TY - CHAP TI - Android’s Security Framework--Understanding the Security of Mobile Phone Platforms AU - Enck, William T2 - Encyclopedia of Cryptography and Security PY - 2011/// SP - 34-37 PB - Springer US ER - TY - THES TI - Analysis Techniques for Mobile Operating System Security AU - Enck, William Harold DA - 2011/// PY - 2011/// PB - The Pennsylvania State University ER - TY - RPRT TI - Seeding a Security-Enhancing Infrastructure for Multi-market Application Ecosystems AU - Barrera, David AU - Enck, William AU - Oorschot, Paul C A3 - Technical report, School of Computer Science, Carleton University, http … DA - 2011/// PY - 2011/// PB - Technical report, School of Computer Science, Carleton University, http … ER - TY - CHAP TI - ARP Spoofing AU - Enck, William T2 - Encyclopedia of Cryptography and Security PY - 2011/// SP - 48-49 PB - Springer US ER - TY - CONF TI - A Study of Android Application Security. AU - Enck, William AU - Octeau, Damien AU - McDaniel, Patrick AU - Chaudhuri, Swarat C2 - 2011/// C3 - USENIX Security Symposium DA - 2011/// ER - TY - ER - TY - JOUR TI - A systematic literature review of actionable alert identification techniques for automated static code analysis AU - Heckman, Sarah AU - Williams, Laurie T2 - Information and Software Technology DA - 2011/// PY - 2011/// VL - 53 IS - 4 SP - 363-387 ER - TY - CONF TI - Tainted Flow Analysis on e-SSA-Form Programs AU - Rimsa, Andrei AU - d’Amorim, Marcelo AU - Pereira, Fernando Magno Quintão AB - Tainted flow attacks originate from program inputs maliciously crafted to exploit software vulnerabilities. These attacks are common in server-side scripting languages, such as PHP. In 1997, Ørbæk and Palsberg formalized the problem of detecting these exploits as an instance of type-checking, and gave an O(V 3) algorithm to solve it, where V is the number of program variables. A similar algorithm was, ten years later, implemented on the Pixy tool. In this paper we give an O(V 2) solution to the same problem. Our solution uses Bodik et al.’s extended Static Single Assignment (e-SSA) program representation. The e-SSA form can be efficiently computed and it enables us to solve the problem via a sparse data-flow analysis. Using the same infrastructure, we compared a state-of-the-art data-flow solution with our technique. Both approaches have detected 36 vulnerabilities in well known PHP programs. Our results show that our approach tends to outperform the data-flow algorithm for bigger inputs. We have reported the bugs that we found, and an implementation of our algorithm is now publicly available. C2 - 2011/// C3 - Compiler Construction - 20th International Conference, CC 2011, Held as Part of the Joint European Conferences on Theory and Practice of Software, ETAPS 2011, Saarbrücken, Germany, March 26-April 3, 2011. Proceedings DA - 2011/// DO - 10.1007/978-3-642-19861-8_8 SP - 124-143 UR - https://doi.org/10.1007/978-3-642-19861-8_8 ER - TY - CONF TI - NASA Formal Methods - Third International Symposium, NFM 2011, Pasadena, CA, USA, April 18-20, 2011. Proceedings A2 - Bobaru, Mihaela Gheorghiu A2 - Havelund, Klaus A2 - Holzmann, Gerard J. A2 - Joshi, Rajeev AB - This book constitutes the refereed proceedings of the Third International Symposium on NASA Formal Methods, NFM 2011, held in Pasadena, CA, USA, in April 2011. The 26 revised full papers presented tog C2 - 2011/// DA - 2011/// DO - 10.1007/978-3-642-20398-5 VL - 6617 PB - Springer UR - https://doi.org/10.1007/978-3-642-20398-5 ER - TY - CONF TI - Fault-localization using dynamic slicing and change impact analysis AB - Spectrum-based fault-localization tools, such as Tarantula, have been developed to help guide developers towards faulty statements in a system under test. These tools report statements ranked in order of suspiciousness. Unfortunately, the reported statements can often be unrelated to the error. This paper evaluates the impact of several approaches to ignoring such unrelated statements in order to improve the effectiveness of fault-localization tools. C2 - 2011/// C3 - 26th IEEE/ACM International Conference on Automated Software Engineering (ASE 2011), Lawrence, KS, USA, November 6-10, 2011 DA - 2011/// DO - 10.1109/ASE.2011.6100114 SP - 520-523 UR - https://doi.org/10.1109/ASE.2011.6100114 ER - TY - CONF TI - Compiler Construction - 20th International Conference, CC 2011, Held as Part of the Joint European Conferences on Theory and Practice of Software, ETAPS 2011, Saarbrücken, Germany, March 26-April 3, 2011. Proceedings A2 - Knoop, Jens C2 - 2011/// DA - 2011/// DO - 10.1007/978-3-642-19861-8 VL - 6601 PB - Springer UR - https://doi.org/10.1007/978-3-642-19861-8 ER - TY - CONF TI - 26th IEEE/ACM International Conference on Automated Software Engineering (ASE 2011), Lawrence, KS, USA, November 6-10, 2011 A2 - Alexander, Perry A2 - Pasareanu, Corina S. A2 - Hosking, John G. C2 - 2011/// DA - 2011/// PB - IEEE Computer Society UR - http://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=6093623 ER - TY - CONF TI - CORAL: Solving Complex Constraints for Symbolic PathFinder AU - Souza, Matheus AU - Borges, Mateus AU - d’Amorim, Marcelo AU - Pasareanu, Corina S. AB - Symbolic execution is a powerful automated technique for generating test cases. Its goal is to achieve high coverage of software. One major obstacle in adopting the technique in practice is its inability to handle complex mathematical constraints. To address the problem, we have integrated CORAL’s heuristic solvers into NASA Ames’ Symbolic PathFinder symbolic execution tool. CORAL’s solvers have been designed to deal with mathematical constraints and their heuristics have been improved based on examples from the aerospace domain. This integration significantly broadens the application of Symbolic PathFinder at NASA and in industry. C2 - 2011/// C3 - NASA Formal Methods - Third International Symposium, NFM 2011, Pasadena, CA, USA, April 18-20, 2011. Proceedings DA - 2011/// DO - 10.1007/978-3-642-20398-5_26 SP - 359-374 UR - https://doi.org/10.1007/978-3-642-20398-5_26 ER - TY - JOUR TI - Worst-Case Fair Bin Sort Queuing (WBSQ): An O(1) Worst-Case Fair Scheduler AU - Dwekat, Zyad A. AU - Rouskas, George N. AU - IEEE T2 - 2011 Ieee International Conference on Communications (Icc) DA - 2011/// PY - 2011/// ER - TY - JOUR TI - On Optimal Tiered Structures for Network Service Bundles AU - Lv, Qian AU - Rouskas, George N. AU - IEEE T2 - 2011 Ieee Global Telecommunications Conference (Globecom 2011) DA - 2011/// PY - 2011/// ER - TY - JOUR TI - Hybrid FRR/p-Cycle MPLS Link Protection Design AU - Cao, Chang AU - Rouskas, George N. AU - IEEE T2 - 2011 Ieee Global Telecommunications Conference (Globecom 2011) DA - 2011/// PY - 2011/// ER - TY - JOUR TI - Flow Isolation in Optical Networks AU - Wang, Hui AU - Rouskas, George N. AU - IEEE T2 - 2011 18th Ieee Workshop on Local and Metropolitan Area Networks (Lanman) DA - 2011/// PY - 2011/// ER - TY - JOUR TI - Demonstration of QoS-Aware Video Streaming over a Metro-Scale Optical Network Using a Cross-Layer Architectural Design AU - Wang, Michael S. AU - Wang, Anjing AU - Bathula, Balagangadhar G. AU - Lai, Caroline P. AU - Baldine, Ilia AU - Chen, Cathy AU - Majumder, Debjyoti AU - Gurkan, Deniz AU - Rouskas, George N. AU - Dutta, Rudra AU - Bergman, Keren AU - America, Optical Society T2 - 2011 Optical Fiber Communication Conference and Exposition (Ofc/nfoec) and the National Fiber Optic Engineers Conference DA - 2011/// PY - 2011/// ER - TY - JOUR TI - A One-Layer Recurrent Neural Network for Pseudoconvex Optimization Subject to Linear Equality Constraints AU - Guo, Zhishan AU - Liu, Qingshan AU - Wang, Jun T2 - IEEE Transactions on Neural Networks AB - In this paper, a one-layer recurrent neural network is presented for solving pseudoconvex optimization problems subject to linear equality constraints. The global convergence of the neural network can be guaranteed even though the objective function is pseudoconvex. The finite-time state convergence to the feasible region defined by the equality constraints is also proved. In addition, global exponential convergence is proved when the objective function is strongly pseudoconvex on the feasible region. Simulation results on illustrative examples and application on chemical process data reconciliation are provided to demonstrate the effectiveness and characteristics of the neural network. DA - 2011/12// PY - 2011/12// DO - 10.1109/tnn.2011.2169682 VL - 22 IS - 12 SP - 1892-1900 J2 - IEEE Trans. Neural Netw. OP - SN - 1045-9227 1941-0093 UR - http://dx.doi.org/10.1109/tnn.2011.2169682 DB - Crossref ER - TY - ER - TY - ER - TY - ER - TY - CONF TI - Building human-level AI for real-time strategy games AU - Weber, B.G. AU - Mateas, M. AU - Jhala, A. C2 - 2011/// C3 - AAAI Fall Symposium - Technical Report DA - 2011/// VL - FS-11-01 SP - 329-336 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84856478459&partnerID=MN8TOARS ER - TY - CONF TI - A particle model for state estimation in real-time strategy games AU - Weber, B.G. AU - Mateas, M. AU - Jhala, A. C2 - 2011/// C3 - Proceedings of the 7th AAAI Conference on Artificial Intelligence and Interactive Digital Entertainment, AIIDE 2011 DA - 2011/// SP - 103-108 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84871961742&partnerID=MN8TOARS ER - TY - CONF TI - Modeling player retention in Madden NFL 11 AU - Weber, B.G. AU - John, M. AU - Mateas, M. AU - Jhala, A. C2 - 2011/// C3 - Proceedings of the National Conference on Artificial Intelligence DA - 2011/// VL - 2 SP - 1701-1706 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80055032087&partnerID=MN8TOARS ER - TY - CONF TI - Symmetric determinantal representation of weakly skew circuits AU - Grenet, Bruno AU - Kaltofen, Erich L. AU - Koiran, Pascal AU - Portier, Natacha T2 - Symposium on Theoretical Aspects of Computer Science (STACS 2011) A2 - Dürr, Christoph A2 - Schwentick, Thomas C2 - 2011/// C3 - Proceedings of the Symposium on Theoretical Aspects of Computer Science (STACS 2011) CY - Dortmund, Germany DA - 2011/// PY - 2011/3// SP - 543–554 ER - TY - CONF TI - Automatic Generation of Proof Problems in Deductive Logic AU - Mostafavi, Behrooz AU - Barnes, Tiffany AU - Croy, Marvin T2 - 4th International Conference on Educational Data Mining C2 - 2011/// C3 - Proceedings of the 4th International Conference on Educational Data Mining (EDM 2011) CY - Eindhoven, Netherlands DA - 2011/// PY - 2011/7/6/ SP - 289–294 ER - TY - CONF TI - The EDM Vis Tool AU - Johnson, Matt AU - Eagle, Michael AU - Joseph, Leena AU - Barnes, Tiffany T2 - EDM 2011 C2 - 2011/// C3 - Electronic Data Mining DA - 2011/// PY - 2011/// SP - 349–350 ER - TY - JOUR TI - Enhancing the Automatic Generation of Hints with Expert Seeding AU - Stamper, John AU - Barnes, Tiffany AU - Croy, Marvin T2 - International Journal of Artificial Intelligence in Education DA - 2011/// PY - 2011/// VL - 21 IS - 1-2 SP - 153-167 ER - TY - JOUR TI - Quality of service-based multi-domain routing under multiple quality of service metrics AU - Yiltas, D. AU - Perros, H. T2 - IET Communications AB - Applications such as voice and video require network paths that satisfy several different quality of service (QoS) metrics, such as delay, jitter, packet loss rate and availability. The calculation of paths under multiple QoS metrics, such as the above four metrics, is a difficult problem since these metrics are in general incompatible. The authors propose a simple method for combining the above four QoS metrics into a single composite QoS metric which can be used as a link cost in Dijkstra's algorithm in order to calculate a path. The authors evaluated the proposed method in a multi-domain routing environment where domain reachability information is available through a service oriented architecture paradigm, and they show that it outperforms two commonly used methods. The results are also applicable to routing within a single domain. DA - 2011/2/11/ PY - 2011/2/11/ DO - 10.1049/iet-com.2010.0144 VL - 5 IS - 3 SP - 327-336 LA - en OP - SN - 1751-8628 1751-8636 UR - http://dx.doi.org/10.1049/iet-com.2010.0144 DB - Crossref ER - TY - CONF TI - High-performing scale-out solution for deep packet processing via adaptive load-balancing AU - Battestilli, Lina AU - Nelms, Terry AU - Hunter, Steven W. AU - Shippy, Gary T2 - Metropolitan Area Networks (LANMAN) AB - We propose a scale-out solution for deep packet processing (DPP) appliances, which uses a standard Ethernet switch in combination with a load balancing controller. The majority of the data-plane traffic is distributed via the switch's built-in traffic distribution function and no connection state is kept. If the load balancing controller detects a skew in the load of the DPP appliances, it updates the traffic rules in the switch to redirect new connections to less busy DPP appliances. This adaptive solution is beneficial for load-balancing at high data rates because state is kept for only the redirected connections. For typical traffic patterns, our solution reduces the packet drops with minimal connection redirection. We show an example capture, where we are able to improve the packet drop rate by 94.8% with only 3% of the connections being redirected. C2 - 2011/10// C3 - 2011 18th IEEE Workshop on Local & Metropolitan Area Networks (LANMAN) DA - 2011/10// DO - 10.1109/lanman.2011.6076946 PB - IEEE SN - 9781457712647 UR - http://dx.doi.org/10.1109/lanman.2011.6076946 DB - Crossref ER - TY - CONF TI - Poster: What's on your mind?: a mind-based driving alert system AU - Navuluri, Karthik AU - Padia, Kalpesh AU - Gupta, Ajay AU - Nadeem, Tamer T2 - ACM C2 - 2011/// C3 - Proceedings of the 9th international conference on Mobile systems, applications, and services DA - 2011/// SP - 415-416 ER - TY - CONF TI - A student-written wiki textbook supplement for a parallel-architecture course AU - Gehringer, Edward F. AU - Navalakha, Karishma AU - Kadanjoth, Reejesh T2 - Workshop on Computer Architecture Education, associated with HPCA-17, High-Performance Computer Architecture C2 - 2011/// C3 - Proceedings of the HPCA-17: Workshop on Computer Architecture Education CY - San Antonio, TX DA - 2011/// PY - 2011/2/13/ ER - TY - JOUR TI - Astrojumper: Motivating Exercise with an Immersive Virtual Reality Exergame AU - Finkelstein, Samantha L. AU - Nickel, Andrea AU - Lipps, Zachary AU - Barnes, Tiffany AU - Wartell, Zachary AU - Suma, Evan A. T2 - Presence: Teleoperators and Virtual Environments AB - We present the design and evaluation of Astrojumper, an immersive virtual reality exergame developed to motivate players to engage in rigorous, full-body exercise. We performed a user study with 30 people between the ages of 6 and 50 who played the game for 15 min. Regardless of differences in age, gender, activity level, and video game experience, participants rated Astrojumper extremely positively and experienced a significant increase in heart rate after gameplay. Additionally, we found that participants' ratings of perceived workout intensity positively correlated with their level of motivation. Overall, our results demonstrate that Astrojumper effectively motivates both children and adults to exercise through immersive virtual reality technology and a simple, yet engaging, game design. DA - 2011/2// PY - 2011/2// DO - 10.1162/pres_a_00036 VL - 20 IS - 1 SP - 78-92 SN - 1054-7460 1531-3263 UR - http://dx.doi.org/10.1162/pres_a_00036 ER - TY - JOUR TI - Guest editorial: learning to organize testing AU - Bener, Ayse AU - Menzies, Tim T2 - Automated Software Engineering AB - At the start of the decade, two publications (Shull et al. 2002; Boehm and Basili 2001) described the start-of-the art in defect reduction. Since then, there has been considerable research into data mining of defect data; e.g. Menzies et al. (2007). The data mining work has become less about defect reduction, and more about how to organize a project’s test resources in order to improve product quality by (say) defining a procedure such that the modules most likely to contain defects are inspected first (Menzies et al. 2010). After a decade of intensive work into data mining to make best use of testing resources, it is time to ask: what have we learned from all that research? Some of that research offers success stories with (e.g.) • Reducing the costs to find defects (Menzies et al. 2010); • Generalizing defect predictors to other projects (Tosun et al. 2011); • Tuning those predictors to different business goals (Turhan et al. 2009). DA - 2011/10/7/ PY - 2011/10/7/ DO - 10.1007/S10515-011-0095-Y VL - 19 IS - 2 SP - 137-140 J2 - Autom Softw Eng LA - en OP - SN - 0928-8910 1573-7535 UR - http://dx.doi.org/10.1007/S10515-011-0095-Y DB - Crossref ER - TY - JOUR TI - Kernel methods for software effort estimation AU - Kocaguneli, Ekrem AU - Menzies, Tim AU - Keung, Jacky W. T2 - Empirical Software Engineering DA - 2011/12/10/ PY - 2011/12/10/ DO - 10.1007/S10664-011-9189-1 VL - 18 IS - 1 SP - 1-24 J2 - Empir Software Eng LA - en OP - SN - 1382-3256 1573-7616 UR - http://dx.doi.org/10.1007/S10664-011-9189-1 DB - Crossref KW - Effort estimation KW - Data mining KW - Kernel function KW - Bandwidth ER - TY - CONF TI - Commitments with Regulations: Reasoning about Safety and Control in R EGULA AU - Marengo, Elisa AU - Baldoni, Matteo AU - Chopra, Amit K. AU - Baroglio, Cristina AU - Patti, Viviana AU - Singh, Munindar P. T2 - International Conference on Autonomous Agents and MultiAgent Systems C2 - 2011/5// C3 - Proceedings of the 10th International Conference on Autonomous Agents and MultiAgent Systems (AAMAS) CY - Taipei, Taiwan DA - 2011/5// PY - 2011/5// SP - 467–474 PB - IFAAMAS ER - TY - CONF TI - A Unified Framework for Trust in Composite Networks AU - Adalı, Sibel AU - Wallace, William A. AU - Qi, Yi AU - Vijayakumar, Priyankaa AU - Singh, Munindar P. T2 - Autonomous Agents & Multi-Agent Systems Workshop on Trust in Agent Societies C2 - 2011/// C3 - Proceedings of the 13th Autonomous Agents & Multi-Agent Systems Workshop on Trust in Agent Societies CY - Taipei, Taiwan DA - 2011/// PY - 2011/5/2/ SP - 1–12 ER - TY - CHAP TI - Affect, Learning, and Delight AU - Lester, James C. T2 - Affective Computing and Intelligent Interaction. ACII 2011 A2 - D'Mello, S. A2 - Graesser, A. A2 - Schuller, B. A2 - Martin, J.C. T3 - Lecture Notes in Computer Science AB - Because of the growing recognition of the role that affect plays in learning, affective computing has become the subject of increasing attention in research on interactive learning environments. The intelligent tutoring systems community has begun actively exploring computational models of affect, and game-based learning environments present a significant opportunity for investigating student affect in interactive learning. One family of game-based learning environments, narrative-centered learning environments, offer a particularly compelling laboratory for investigating student affect. In narrative-centered environments, learning activities play out in dynamically generated interactive narratives and training scenarios. These afford significant opportunities for investigating computational models of student emotion. In this talk, we explore the role that affective computing can play in next-generation interactive learning environments, with a particular focus on affect recognition, affect understanding, and affect synthesis in game-based learning. PY - 2011/// DO - 10.1007/978-3-642-24600-5_2 SP - 2–2 PB - Springer SN - 9783642245992 9783642246005 SV - 6974 UR - http://dx.doi.org/10.1007/978-3-642-24600-5_2 ER - TY - JOUR TI - A hybrid classification scheme for mining multisource geospatial data AU - Vatsavai, Ranga Raju AU - Bhaduri, Budhendra T2 - GeoInformatica DA - 2011/1// PY - 2011/1// DO - 10.1007/S10707-010-0113-4 VL - 15 IS - 1 SP - 29–47 SN - 1384-6175 1573-7624 UR - http://dx.doi.org/10.1007/S10707-010-0113-4 KW - MLC KW - EM KW - Semi-supervised learning ER - TY - JOUR TI - Resumption strategies for interrupted programming tasks AU - Parnin, Chris AU - Rugaber, Spencer T2 - Software Quality Journal DA - 2011/// PY - 2011/// DO - 10.1007/S11219-010-9104-9 VL - 19 IS - 1 SP - 5–34 SN - 0963-9314 1573-1367 UR - http://dx.doi.org/10.1007/S11219-010-9104-9 KW - Interruption KW - Resumption strategies KW - Task context KW - Task knowledge ER - TY - CHAP TI - Array Regrouping on CMP with Non-uniform Cache Sharing AU - Jiang, Yunlian AU - Zhang, Eddy Z. AU - Shen, Xipeng AU - Gao, Yaoqing AU - Archambault, Roch T2 - Languages and Compilers for Parallel Computing AB - Array regrouping enhances program spatial locality by interleaving elements of multiple arrays that tend to be accessed closely. Its effectiveness has been systematically studied for sequential programs running on unicore processors, but not for multithreading programs on modern Chip Multiprocessor (CMP) machines. On one hand, the processor-level parallelism on CMP intensifies memory bandwidth pressure, suggesting the potential benefits of array regrouping for CMP computing. On the other hand, CMP architectures exhibit extra complexities—especially the hierarchical, heterogeneous cache sharing among hyperthreads, cores, and processors—that impose new challenges to array regrouping. In this work, we initiate an exploration to the new opportunities and challenges. We propose cache-sharing-aware reference affinity analysis for identifying data affinity in multithreading applications. The analysis consists of affinity-guided thread scheduling and hierarchical reference-vector merging, handles cache sharing among both hyperthreads and cores, and offers hints for array regrouping and the avoidance of false sharing. Preliminary experiments demonstrate the potential of the techniques in improving locality of multithreading applications on CMP with various pitfalls avoided. PY - 2011/// DO - 10.1007/978-3-642-19595-2_7 SP - 92-105 OP - PB - Springer Berlin Heidelberg SN - 9783642195945 9783642195952 UR - http://dx.doi.org/10.1007/978-3-642-19595-2_7 DB - Crossref ER - TY - JOUR TI - Data Mining in Earth System Science (DMESS 2011) AU - Hoffman, Forrest M. AU - Larson, J. Walter AU - Mills, Richard Tran AU - Brooks, Bjørn-Gustaf J. AU - Ganguly, Auroop R. AU - Hargrove, William W. AU - Huang, Jian AU - Kumar, Jitendra AU - Vatsavai, Ranga R. T2 - Procedia Computer Science AB - From field-scale measurements to global climate simulations and remote sensing, the growing body of very large and long time series Earth science data are increasingly difficult to analyze, visualize, and interpret. Data mining, information theoretic, and machine learning techniques—such as cluster analysis, singular value decomposition, block entropy, Fourier and wavelet analysis, phase-space reconstruction, and artificial neural networks—are being applied to problems of segmentation, feature extraction, change detection, model-data comparison, and model validation. The size and complexity of Earth science data exceed the limits of most analysis tools and the capacities of desktop computers. New scalable analysis and visualization tools, running on parallel cluster computers and supercomputers, are required to analyze data of this magnitude. This workshop will demonstrate how data mining techniques are applied in the Earth sciences and describe innovative computer science methods that support analysis and discovery in the Earth sciences. DA - 2011/// PY - 2011/// DO - 10.1016/j.procs.2011.04.157 VL - 4 SP - 1450-1455 J2 - Procedia Computer Science LA - en OP - SN - 1877-0509 UR - http://dx.doi.org/10.1016/j.procs.2011.04.157 DB - Crossref KW - Data mining KW - remote sensing KW - high performance computing KW - segmentation KW - change detection KW - synthesis KW - visualization ER - TY - JOUR TI - GX-Means: A model-based divide and merge algorithm for geospatial image clustering AU - Vatsavai, Ranga R. AU - Symons, Christopher T. AU - Chandola, Varun AU - Jun, Goo T2 - Procedia Computer Science AB - One of the practical issues in clustering is the specification of the appropriate number of clusters, which is not obvious when analyzing geospatial datasets, partly because they are huge (both in size and spatial extent) and high dimensional. In this paper we present a computationally effcient model-based split and merge clustering algorithm that incrementally finds model parameters and the number of clusters. Additionally, we attempt to provide insights into this problem and other data mining challenges that are encountered when clustering geospatial data. The basic algorithm we present is similar to the G-means and X-means algorithms; however, our proposed approach avoids certain limitations of these well-known clustering algorithms that are pertinent when dealing with geospatial data. We compare the performance of our approach with the G-means and X-means algorithms. Experimental evaluation on simulated data and on multispectral and hyperspectral remotely sensed image data demonstrates the effectiveness of our algorithm. DA - 2011/// PY - 2011/// DO - 10.1016/j.procs.2011.04.020 VL - 4 SP - 186-195 J2 - Procedia Computer Science LA - en OP - SN - 1877-0509 UR - http://dx.doi.org/10.1016/j.procs.2011.04.020 DB - Crossref KW - Clustering KW - EM KW - GMM KW - K-means KW - G-means KW - X-means ER - TY - JOUR TI - A scalable gaussian process analysis algorithm for biomass monitoring AU - Chandola, Varun AU - Vatsavai, Ranga Raju T2 - Statistical Analysis and Data Mining AB - Abstract Biomass monitoring is vital for studying the carbon cycle of earth's ecosystem and has several significant implications, especially in the context of understanding climate change and its impacts. Recently, several change detection methods have been proposed to identify land cover changes in temporal profiles (time series) of vegetation collected using remote sensing instruments, but do not satisfy one or both of the two requirements of the biomass monitoring problem, that is, operating in online mode and handling periodic time series . In this paper, we adapt Gaussian process (GP) regression to detect changes in such time series in an online fashion. While GP have been widely used as a kernel‐based learning method for regression and classification, their applicability to massive spatiotemporal data sets, such as remote sensing data, has been limited owing to the high computational costs involved. We focus on addressing the scalability issues associated with the proposed GP based change detection algorithm. This paper makes several significant contributions. First, we propose a GP based online time series change detection algorithm and demonstrate its effectiveness in detecting different types of changes in Normalized Difference Vegetation Index (NDVI) data obtained from a study area in IA, USA. Second, we propose an efficient Toeplitz matrix based solution which significantly improves the computational complexity and memory requirements of the proposed GP based method. Specifically, the proposed solution can analyze a time series of length t in O ( t 2 ) time while maintaining a O ( t ) memory footprint, compared to the O ( t 3 ) time and O ( t 2 ) memory requirement of standard matrix manipulation based methods. Third, we describe a parallel version of the proposed solution which can be used to simultaneously analyze a large number of time series. We study three different parallel implementations: using threads, Message Passing Interface (MPI), and a hybrid implementation using threads and MPI. Experimental results show that the hybrid implementation scales better than the multithreaded and MPI based implementations. The application of the proposed scalable algorithm is demonstrated in analyzing massive remote sensing observation data. The hybrid implementation, using 1536 computing cores, can analyze an NDVI data set for the Iowa study area in nearly 5 s, while a serial algorithm, using standard Cholesky decomposition based routines, takes several days to process the same data set. © 2011 Wiley Periodicals, Inc. Statistical Analysis and Data Mining 4: 430–445, 2011 DA - 2011/7/8/ PY - 2011/7/8/ DO - 10.1002/sam.10129 VL - 4 IS - 4 SP - 430-445 J2 - Statistical Analy Data Mining LA - en OP - SN - 1932-1864 UR - http://dx.doi.org/10.1002/sam.10129 DB - Crossref ER - TY - JOUR TI - The Complexity of Optimal Job Co-Scheduling on Chip Multiprocessors and Heuristics-Based Solutions AU - Jiang, Yunlian AU - Tian, Kai AU - Shen, Xipeng AU - Zhang, Jinghe AU - Chen, Jie AU - Tripathi, Rahul T2 - IEEE Transactions on Parallel and Distributed Systems AB - In Chip Multiprocessors (CMPs) architecture, it is common that multiple cores share some on-chip cache. The sharing may cause cache thrashing and contention among co-running jobs. Job co-scheduling is an approach to tackling the problem by assigning jobs to cores appropriately so that the contention and consequent performance degradations are minimized. Job co-scheduling includes two tasks: the estimation of co-run performance, and the determination of suitable co-schedules. Most existing studies in job co-scheduling have concentrated on the first task but relies on simple techniques (e.g., trying different schedules) for the second. This paper presents a systematic exploration to the second task. The paper uncovers the computational complexity of the determination of optimal job co-schedules, proving its NP-completeness. It introduces a set of algorithms, based on graph theory and Integer/Linear Programming, for computing optimal co-schedules or their lower bounds in scenarios with or without job migrations. For complex cases, it empirically demonstrates the feasibility for approximating the optimal effectively by proposing several heuristics-based algorithms. These discoveries may facilitate the assessment of job co-schedulers by providing necessary baselines, as well as shed insights to the development of co-scheduling algorithms in practical systems. DA - 2011/7// PY - 2011/7// DO - 10.1109/TPDS.2010.193 VL - 22 IS - 7 SP - 1192-1205 J2 - IEEE Trans. Parallel Distrib. Syst. OP - SN - 1045-9219 UR - http://dx.doi.org/10.1109/TPDS.2010.193 DB - Crossref KW - Co-scheduling KW - shared cache KW - CMP scheduling KW - cache contention KW - perfect matching KW - integer programming ER - TY - CONF TI - On-the-fly elimination of dynamic irregularities for GPU computing AU - Zhang, Eddy Z. AU - Jiang, Yunlian AU - Guo, Ziyu AU - Tian, Kai AU - Shen, Xipeng T2 - the sixteenth international conference AB - The power-efficient massively parallel Graphics Processing Units (GPUs) have become increasingly influential for general-purpose computing over the past few years. However, their efficiency is sensitive to dynamic irregular memory references and control flows in an application. Experiments have shown great performance gains when these irregularities are removed. But it remains an open question how to achieve those gains through software approaches on modern GPUs.This paper presents a systematic exploration to tackle dynamic irregularities in both control flows and memory references. It reveals some properties of dynamic irregularities in both control flows and memory references, their interactions, and their relations with program data and threads. It describes several heuristics-based algorithms and runtime adaptation techniques for effectively removing dynamic irregularities through data reordering and job swapping. It presents a framework, G-Streamline, as a unified software solution to dynamic irregularities in GPU computing. G-Streamline has several distinctive properties. It is a pure software solution and works on the fly, requiring no hardware extensions or offline profiling. It treats both types of irregularities at the same time in a holistic fashion, maximizing the whole-program performance by resolving conflicts among optimizations. Its optimization overhead is largely transparent to GPU kernel executions, jeopardizing no basic efficiency of the GPU application. Finally, it is robust to the presence of various complexities in GPU applications. Experiments show that G-Streamline is effective in reducing dynamic irregularities in GPU computing, producing speedups between 1.07 and 2.5 for a variety of applications. C2 - 2011/// C3 - Proceedings of the sixteenth international conference on Architectural support for programming languages and operating systems - ASPLOS '11 DA - 2011/// DO - 10.1145/1950365.1950408 PB - ACM Press SN - 9781450302661 UR - http://dx.doi.org/10.1145/1950365.1950408 DB - Crossref ER - TY - CONF TI - A step towards transparent integration of input-consciousness into dynamic program optimizations AU - Tian, Kai AU - Zhang, Eddy AU - Shen, Xipeng T2 - the 2011 ACM international conference AB - Dynamic program optimizations are critical for the efficiency of applications in managed programming languages and scripting languages. Recent studies have shown that exploitation of program inputs may enhance the effectiveness of dynamic optimizations significantly. However, current solutions for enabling the exploitation require either programmers' annotations or intensive offline profiling, impairing the practical adoption of the techniques. C2 - 2011/// C3 - Proceedings of the 2011 ACM international conference on Object oriented programming systems languages and applications - OOPSLA '11 DA - 2011/// DO - 10.1145/2048066.2048103 PB - ACM Press SN - 9781450309400 UR - http://dx.doi.org/10.1145/2048066.2048103 DB - Crossref ER - TY - CONF TI - Correctly Treating Synchronizations in Compiling Fine-Grained SPMD-Threaded Programs for CPU AU - Guo, Ziyu AU - Zhang, Eddy Zheng AU - Shen, Xipeng T2 - 2011 International Conference on Parallel Architectures and Compilation Techniques (PACT) AB - Automatic compilation for multiple types of devices is important, especially given the current trends towards heterogeneous computing. This paper concentrates on some issues in compiling fine-grained SPMD-threaded code (e.g., GPU CUDA code) for multicore CPUs. It points out some correctness pitfalls in existing techniques, particularly in their treatment to implicit synchronizations. It then describes a systematic dependence analysis specially designed for handling implicit synchronizations in SPMD-threaded programs. By unveiling the relations between inter-thread data dependences and correct treatment to synchronizations, it presents a dependence-based solution to the problem. Experiments demonstrate that the proposed techniques can resolve the correctness issues in existing compilation techniques, and help compilers produce correct and efficient translation results. C2 - 2011/10// C3 - 2011 International Conference on Parallel Architectures and Compilation Techniques DA - 2011/10// DO - 10.1109/pact.2011.62 PB - IEEE SN - 9781457717949 9780769545660 UR - http://dx.doi.org/10.1109/pact.2011.62 DB - Crossref ER - TY - CONF TI - Enhancing Data Locality for Dynamic Simulations through Asynchronous Data Transformations and Adaptive Control AU - Wu, Bo AU - Zhang, Eddy Z. AU - Shen, Xipeng T2 - 2011 International Conference on Parallel Architectures and Compilation Techniques (PACT) AB - Many dynamic simulation programs contain complex, irregular memory reference patterns, and require runtime optimizations to enhance data locality. Current approaches periodically stop the execution of an application to reorder the computation or data based on the current program state to improve the data locality for the next period of execution. In this work, we examine the implications that modern heterogeneous Chip Multiprocessors (CMP) architecture imposes on the optimization paradigm. We develop three techniques to enhance the optimizations. The first is asynchronous data transformation, which moves data reordering off the critical path through dependence circumvention. The second is a novel data transformation algorithm, named TLayout, designed specially to take advantage of modern throughput-oriented processors. Together they provide two complementary ways to attack a benefit-overhead dilemma inherited in traditional techniques. Working with a dynamic adaptation scheme, the techniques produce significant performance improvement for a set of dynamic simulation benchmarks. C2 - 2011/10// C3 - 2011 International Conference on Parallel Architectures and Compilation Techniques DA - 2011/10// DO - 10.1109/pact.2011.56 PB - IEEE SN - 9781457717949 9780769545660 UR - http://dx.doi.org/10.1109/pact.2011.56 DB - Crossref ER - TY - CHAP TI - Intelligent Machinima Generation for Visual Storytelling AU - Jhala, Arnav AU - Young, R. Michael T2 - Artificial Intelligence for Computer Games PY - 2011/// DO - 10.1007/978-1-4419-8188-2_7 SP - 151-170 OP - PB - Springer New York SN - 9781441981875 9781441981882 UR - http://dx.doi.org/10.1007/978-1-4419-8188-2_7 DB - Crossref ER - TY - CHAP TI - Escape from Monkey Island: Evading High-Interaction Honeyclients AU - Kapravelos, Alexandros AU - Cova, Marco AU - Kruegel, Christopher AU - Vigna, Giovanni T2 - Detection of Intrusions and Malware, and Vulnerability Assessment AB - High-interaction honeyclients are the tools of choice to detect malicious web pages that launch drive-by-download attacks. Unfortunately, the approach used by these tools, which, in most cases, is to identify the side-effects of a successful attack rather than the attack itself, leaves open the possibility for malicious pages to perform evasion techniques that allow one to execute an attack without detection or to behave in a benign way when being analyzed. In this paper, we examine the security model that high-interaction honeyclients use and evaluate their weaknesses in practice. We introduce and discuss a number of possible attacks, and we test them against several popular, well-known high-interaction honeyclients. Our attacks evade the detection of these tools, while successfully attacking regular visitors of malicious web pages. PY - 2011/// DO - 10.1007/978-3-642-22424-9_8 SP - 124-143 OP - PB - Springer Berlin Heidelberg SN - 9783642224232 9783642224249 UR - http://dx.doi.org/10.1007/978-3-642-22424-9_8 DB - Crossref ER - TY - JOUR TI - Learning patterns of university student retention AU - Nandeshwar, Ashutosh AU - Menzies, Tim AU - Nelson, Adam T2 - Expert Systems with Applications AB - Learning predictors for student retention is very difficult. After reviewing the literature, it is evident that there is considerable room for improvement in the current state of the art. As shown in this paper, improvements are possible if we (a) explore a wide range of learning methods; (b) take care when selecting attributes; (c) assess the efficacy of the learned theory not just by its median performance, but also by the variance in that performance; (d) study the delta of student factors between those who stay and those who are retained. Using these techniques, for the goal of predicting if students will remain for the first three years of an undergraduate degree, the following factors were found to be informative: family background and family’s social-economic status, high school GPA and test scores. DA - 2011/11// PY - 2011/11// DO - 10.1016/j.eswa.2011.05.048 VL - 38 IS - 12 SP - 14984-14996 J2 - Expert Systems with Applications LA - en OP - SN - 0957-4174 UR - http://dx.doi.org/10.1016/j.eswa.2011.05.048 DB - Crossref KW - Data mining KW - Student retention KW - Predictive modeling KW - Financial aid ER - TY - JOUR TI - Empirically evaluating the application of reinforcement learning to the induction of effective and adaptive pedagogical strategies AU - Chi, Min AU - VanLehn, Kurt AU - Litman, Diane AU - Jordan, Pamela T2 - User Modeling and User-Adapted Interaction DA - 2011/1/5/ PY - 2011/1/5/ DO - 10.1007/S11257-010-9093-1 VL - 21 IS - 1-2 SP - 137-180 J2 - User Model User-Adap Inter LA - en OP - SN - 0924-1868 1573-1391 UR - http://dx.doi.org/10.1007/S11257-010-9093-1 DB - Crossref KW - Reinforcement learning KW - Pedagogical strategy KW - Machine learning KW - Human learning ER - TY - CHAP TI - A Method for Transferring Probabilistic User Models between Environments AU - Roberts, David L. AU - Roberts, Fred T2 - Interactive Storytelling AB - Chief among the inputs to decision making algorithms in narrative or game environments is a model of player or opponent decision making. A challenge that will always face designers is to specify that model ahead of time, when actual data from the environment is likely not to be available. Absent corpora of data, designers must intuit these models as best they can, incorporating domain or expert knowledge when available. To make this process more precise, we derive a theoretically grounded technique to transfer an observed user model from one domain to another. We answer the question: “How can a model obtained from observations of one environment inform a model for another environment?” We verify the accuracy of our techniques using data from previous user studies. PY - 2011/// DO - 10.1007/978-3-642-25289-1_6 SP - 43-54 OP - PB - Springer Berlin Heidelberg SN - 9783642252884 9783642252891 UR - http://dx.doi.org/10.1007/978-3-642-25289-1_6 DB - Crossref ER - TY - JOUR TI - Quantitative proteomic analyses of the response of acidophilic microbial communities to different pH conditions AU - Belnap, Christopher P AU - Pan, Chongle AU - Denef, Vincent J AU - Samatova, Nagiza F AU - Hettich, Robert L AU - Banfield, Jillian F T2 - The ISME Journal AB - Extensive genomic characterization of multi-species acid mine drainage microbial consortia combined with laboratory cultivation has enabled the application of quantitative proteomic analyses at the community level. In this study, quantitative proteomic comparisons were used to functionally characterize laboratory-cultivated acidophilic communities sustained in pH 1.45 or 0.85 conditions. The distributions of all proteins identified for individual organisms indicated biases for either high or low pH, and suggests pH-specific niche partitioning for low abundance bacteria and archaea. Although the proteome of the dominant bacterium, Leptospirillum group II, was largely unaffected by pH treatments, analysis of functional categories indicated proteins involved in amino acid and nucleotide metabolism, as well as cell membrane/envelope biogenesis were overrepresented at high pH. Comparison of specific protein abundances indicates higher pH conditions favor Leptospirillum group III, whereas low pH conditions promote the growth of certain archaea. Thus, quantitative proteomic comparisons revealed distinct differences in community composition and metabolic function of individual organisms during different pH treatments. Proteomic analysis revealed other aspects of community function. Different numbers of phage proteins were identified across biological replicates, indicating stochastic spatial heterogeneity of phage outbreaks. Additionally, proteomic data were used to identify a previously unknown genotypic variant of Leptospirillum group II, an indication of selection for a specific Leptospirillum group II population in laboratory communities. Our results confirm the importance of pH and related geochemical factors in fine-tuning acidophilic microbial community structure and function at the species and strain level, and demonstrate the broad utility of proteomics in laboratory community studies. DA - 2011/1/13/ PY - 2011/1/13/ DO - 10.1038/ismej.2010.200 VL - 5 IS - 7 SP - 1152-1161 J2 - ISME J LA - en OP - SN - 1751-7362 1751-7370 UR - http://dx.doi.org/10.1038/ismej.2010.200 DB - Crossref KW - acid mine drainage KW - communities KW - genotyping KW - perturbation KW - proteomics ER - TY - CHAP TI - Compressing the Incompressible with ISABELA: In-situ Reduction of Spatio-temporal Data AU - Lakshminarasimhan, Sriram AU - Shah, Neil AU - Ethier, Stephane AU - Klasky, Scott AU - Latham, Rob AU - Ross, Rob AU - Samatova, Nagiza F. T2 - Euro-Par 2011 Parallel Processing AB - Modern large-scale scientific simulations running on HPC systems generate data in the order of terabytes during a single run. To lessen the I/O load during a simulation run, scientists are forced to capture data infrequently, thereby making data collection an inherently lossy process. Yet, lossless compression techniques are hardly suitable for scientific data due to its inherently random nature; for the applications used here, they offer less than 10% compression rate. They also impose significant overhead during decompression, making them unsuitable for data analysis and visualization that require repeated data access. To address this problem, we propose an effective method for In-situ Sort-And-B-spline Error-bounded Lossy Abatement (ISABELA) of scientific data that is widely regarded as effectively incompressible. With ISABELA, we apply a preconditioner to seemingly random and noisy data along spatial resolution to achieve an accurate fitting model that guarantees a ≥ 0.99 correlation with the original data. We further take advantage of temporal patterns in scientific data to compress data by ≈ 85%, while introducing only a negligible overhead on simulations in terms of runtime. ISABELA significantly outperforms existing lossy compression methods, such as Wavelet compression. Moreover, besides being a communication-free and scalable compression technique, ISABELA is an inherently local decompression method, namely it does not decode the entire data, making it attractive for random access. PY - 2011/// DO - 10.1007/978-3-642-23400-2_34 SP - 366-379 OP - PB - Springer Berlin Heidelberg SN - 9783642233999 9783642234002 UR - http://dx.doi.org/10.1007/978-3-642-23400-2_34 DB - Crossref ER - TY - CHAP TI - Lessons Learned from Exploring the Backtracking Paradigm on the GPU AU - Jenkins, John AU - Arkatkar, Isha AU - Owens, John D. AU - Choudhary, Alok AU - Samatova, Nagiza F. T2 - Euro-Par 2011 Parallel Processing AB - We explore the backtracking paradigm with properties seen as sub-optimal for GPU architectures, using as a case study the maximal clique enumeration problem, and find that the presence of these properties limit GPU performance to approximately 1.4–2.25 times a single CPU core. The GPU performance “lessons” we find critical to providing this performance include a coarse-and-fine-grain parallelization of the search space, a low-overhead load-balanced distribution of work, global memory latency hiding through coalescence, saturation, and shared memory utilization, and the use of GPU output buffering as a solution to irregular workloads and a large solution domain. We also find a strong reliance on an efficient global problem structure representation that bounds any efficiencies gained from these lessons, and discuss the meanings of these results to backtracking problems in general. PY - 2011/// DO - 10.1007/978-3-642-23397-5_42 SP - 425-437 OP - PB - Springer Berlin Heidelberg SN - 9783642233968 9783642233975 UR - http://dx.doi.org/10.1007/978-3-642-23397-5_42 DB - Crossref ER - TY - CHAP TI - On the Expressiveness of Return-into-libc Attacks AU - Tran, Minh AU - Etheridge, Mark AU - Bletsch, Tyler AU - Jiang, Xuxian AU - Freeh, Vincent AU - Ning, Peng T2 - Lecture Notes in Computer Science AB - Return-into-libc (RILC) is one of the most common forms of code-reuse attacks. In this attack, an intruder uses a buffer overflow or other exploit to redirect control flow through existing (libc) functions within the legitimate program. While dangerous, it is generally considered limited in its expressive power since it only allows the attacker to execute straight-line code. In other words, RILC attacks are believed to be incapable of arbitrary computation—they are not Turing complete. Consequently, to address this limitation, researchers have developed other code-reuse techniques, such as return-oriented programming (ROP). In this paper, we make the counterargument and demonstrate that the original RILC technique is indeed Turing complete. Specifically, we present a generalized RILC attack called Turing complete RILC (TC-RILC) that allows for arbitrary computations. We demonstrate that TC-RILC satisfies formal requirements of Turing-completeness. In addition, because it depends on the well-defined semantics of libc functions, we also show that a TC-RILC attack can be portable between different versions (or even different families) of operating systems and naturally has negative implications for some existing anti-ROP defenses. The development of TC-RILC on both Linux and Windows platforms demonstrates the expressiveness and practicality of the generalized RILC attack. PY - 2011/// DO - 10.1007/978-3-642-23644-0_7 SP - 121-141 OP - PB - Springer Berlin Heidelberg SN - 9783642236433 9783642236440 UR - http://dx.doi.org/10.1007/978-3-642-23644-0_7 DB - Crossref ER - TY - CHAP TI - Taming Information-Stealing Smartphone Applications (on Android) AU - Zhou, Yajin AU - Zhang, Xinwen AU - Jiang, Xuxian AU - Freeh, Vincent W. T2 - Trust and Trustworthy Computing AB - Smartphones have been becoming ubiquitous and mobile users are increasingly relying on them to store and handle personal information. However, recent studies also reveal the disturbing fact that users’ personal information is put at risk by (rogue) smartphone applications. Existing solutions exhibit limitations in their capabilities in taming these privacy-violating smartphone applications. In this paper, we argue for the need of a new privacy mode in smartphones. The privacy mode can empower users to flexibly control in a fine-grained manner what kinds of personal information will be accessible to an application. Also, the granted access can be dynamically adjusted at runtime in a fine-grained manner to better suit a user’s needs in various scenarios (e.g., in a different time or location). We have developed a system called TISSA that implements such a privacy mode on Android. The evaluation with more than a dozen of information-leaking Android applications demonstrates its effectiveness and practicality. Furthermore, our evaluation shows that TISSA introduces negligible performance overhead. PY - 2011/// DO - 10.1007/978-3-642-21599-5_7 SP - 93-107 OP - PB - Springer Berlin Heidelberg SN - 9783642215988 9783642215995 UR - http://dx.doi.org/10.1007/978-3-642-21599-5_7 DB - Crossref ER - TY - CHAP TI - Performatology: A Procedural Acting Approach for Interactive Drama in Cinematic Games AU - Maraffi, Chris Topher AU - Jhala, Arnav T2 - Interactive Storytelling AB - We define a Performatology approach as combining performing arts theory with AI to design Performative Embodied Agents (PEAs) that simulate skilled acting. Our position is that NPC characters for interactive drama, in the traditions of theater and cinema, should be animated by agent behavior modeled on the physical acting of live performers. We propose that agent behavior problems related to generating embodied fictive characterizations are at least in part gestural acting problems that have been addressed in the arts domain. Actors, puppeteers, and animators have successfully portrayed fictive characters that are both believable and appealing to audiences, and therefore similar agent generated characters should attempt to simulate their techniques. PY - 2011/// DO - 10.1007/978-3-642-25289-1_39 VL - 7069 LNCS SP - 322-325 OP - PB - Springer Berlin Heidelberg SN - 9783642252884 9783642252891 UR - http://dx.doi.org/10.1007/978-3-642-25289-1_39 DB - Crossref ER - TY - CHAP TI - Director Agent Intervention Strategies for Interactive Narrative Environments AU - Lee, Seung Y. AU - Mott, Bradford W. AU - Lester, James C. T2 - Interactive Storytelling AB - Interactive narrative environments offer significant potential for creating engaging narrative experiences. Increasingly, applications in education, training, and entertainment are leveraging narrative to create rich interactive experiences in virtual storyworlds. A key challenge posed by these environments is building an effective model of the intervention strategies of director agents that craft customized story experiences for users. Identifying factors that contribute to determining when the next director agent decision should occur is critically important in optimizing narrative experiences. In this work, a dynamic Bayesian network framework was designed to model director agent intervention strategies. To create empirically informed models of director agent intervention decisions, we conducted a Wizard-of-Oz (WOZ) data collection with an interactive narrative-centered learning environment. Using the collected data, dynamic Bayesian network and naïve Bayes models were learned and compared. The performance of the resulting models was evaluated with respect to classification accuracy and produced promising results. PY - 2011/// DO - 10.1007/978-3-642-25289-1_15 SP - 140-151 OP - PB - Springer Berlin Heidelberg SN - 9783642252884 9783642252891 UR - http://dx.doi.org/10.1007/978-3-642-25289-1_15 DB - Crossref ER - TY - CHAP TI - Modeling Learner Affect with Theoretically Grounded Dynamic Bayesian Networks AU - Sabourin, Jennifer AU - Mott, Bradford AU - Lester, James C. T2 - Affective Computing and Intelligent Interaction AB - Evidence of the strong relationship between learning and emotion has fueled recent work in modeling affective states in intelligent tutoring systems. Many of these models are based on general models of affect without a specific focus on learner emotions. This paper presents work that investigates the benefits of using theoretical models of learner emotions to guide the development of Bayesian networks for prediction of student affect. Predictive models are empirically learned from data acquired from 260 students interacting with the game-based learning environment, Crystal Island. Results indicate the benefits of using theoretical models of learner emotions to inform predictive models. The most successful model, a dynamic Bayesian network, also highlights the importance of temporal information in predicting learner emotions. This work demonstrates the benefits of basing predictive models of learner emotions on theoretical foundations and has implications for how these models may be used to validate theoretical models of emotion. PY - 2011/// DO - 10.1007/978-3-642-24600-5_32 SP - 286-295 OP - PB - Springer Berlin Heidelberg SN - 9783642245992 9783642246005 UR - http://dx.doi.org/10.1007/978-3-642-24600-5_32 DB - Crossref ER - TY - CHAP TI - Predicting Facial Indicators of Confusion with Hidden Markov Models AU - Grafsgaard, Joseph F. AU - Boyer, Kristy Elizabeth AU - Lester, James C. T2 - Affective Computing and Intelligent Interaction AB - Affect plays a vital role in learning. During tutoring, particular affective states may benefit or detract from student learning. A key cognitive-affective state is confusion, which has been positively associated with effective learning. Although identifying episodes of confusion presents significant challenges, recent investigations have identified correlations between confusion and specific facial movements. This paper builds on those findings to create a predictive model of learner confusion during task-oriented human-human tutorial dialogue. The model leverages textual dialogue, task, and facial expression history to predict upcoming confusion within a hidden Markov modeling framework. Analysis of the model structure also reveals meaningful modes of interaction within the tutoring sessions. The results demonstrate that because of its predictive power and rich qualitative representation, the model holds promise for informing the design of affective-sensitive tutoring systems. PY - 2011/// DO - 10.1007/978-3-642-24600-5_13 SP - 97-106 OP - PB - Springer Berlin Heidelberg SN - 9783642245992 9783642246005 UR - http://dx.doi.org/10.1007/978-3-642-24600-5_13 DB - Crossref ER - TY - CHAP TI - Generalizing Models of Student Affect in Game-Based Learning Environments AU - Sabourin, Jennifer AU - Mott, Bradford AU - Lester, James C. T2 - Affective Computing and Intelligent Interaction AB - Evidence of the strong relationship between learning and emotion has fueled recent work in modeling affective states in intelligent tutoring systems. Many of these models are designed in ways that limit their ability to be deployed to a large audience of students by using expensive sensors or subject-dependent machine learning techniques. This paper presents work that investigates empirically derived Bayesian networks for prediction of student affect. Predictive models are empirically learned from data acquired from 260 students interacting with the game-based learning environment, Crystal Island. These models are then tested on data from a second identical study involving 140 students to examine issues of generalizability of learned predictive models of student affect. The findings suggest that predictive models of affect that are learned from empirical data may have significant dependencies on the populations on which they are trained, even when the populations themselves are very similar. PY - 2011/// DO - 10.1007/978-3-642-24571-8_73 SP - 588-597 OP - PB - Springer Berlin Heidelberg SN - 9783642245701 9783642245718 UR - http://dx.doi.org/10.1007/978-3-642-24571-8_73 DB - Crossref ER - TY - CHAP TI - When Off-Task is On-Task: The Affective Role of Off-Task Behavior in Narrative-Centered Learning Environments AU - Sabourin, Jennifer AU - Rowe, Jonathan P. AU - Mott, Bradford W. AU - Lester, James C. T2 - Lecture Notes in Computer Science AB - Off-task behavior is the subject of increasing interest in the AI in Education community. This paper reports on an investigation of the role of off-task behavior in narrative-centered learning environments by examining its interactions with student learning gains and affect. Results from an empirical study of students interacting with the Crystal Island environment indicate that off-task behavior generally has negative impacts on learning. However, further analyses of students’ affective transitions suggest that some students may be using off-task behavior as a strategy to regulate negative emotions. PY - 2011/// DO - 10.1007/978-3-642-21869-9_93 SP - 534-536 OP - PB - Springer Berlin Heidelberg SN - 9783642218682 9783642218699 UR - http://dx.doi.org/10.1007/978-3-642-21869-9_93 DB - Crossref ER - TY - CHAP TI - Early Prediction of Cognitive Tool Use in Narrative-Centered Learning Environments AU - Shores, Lucy R. AU - Rowe, Jonathan P. AU - Lester, James C. T2 - Lecture Notes in Computer Science AB - Narrative-centered learning environments introduce novel opportunities for supporting student problem solving and learning. By incorporating cognitive tools into plots and character roles, narrative-centered learning environments can promote self-regulated learning in a manner that is transparent to students. In order to adapt narrative plots to explicitly support effective cognitive tool-use, narrative-centered learning environments need to be able to make early predictions about how effectively students will utilize learning resources. This paper presents results from an investigation into machine-learned models for making early predictions about students’ use of a specific cognitive tool in the Crystal Island learning environment. Multiple classification models are compared and discussed. Findings suggest that support vector machine and naïve Bayes models offer considerable promise for generating useful predictive models of cognitive tool use in narrative-centered learning environments. PY - 2011/// DO - 10.1007/978-3-642-21869-9_42 SP - 320-327 OP - PB - Springer Berlin Heidelberg SN - 9783642218682 9783642218699 UR - http://dx.doi.org/10.1007/978-3-642-21869-9_42 DB - Crossref ER - TY - CHAP TI - Modeling Narrative-Centered Tutorial Decision Making in Guided Discovery Learning AU - Lee, Seung Y. AU - Mott, Bradford W. AU - Lester, James C. T2 - Lecture Notes in Computer Science AB - Interactive narrative-centered learning environments offer significant potential for scaffolding guided discovery learning in rich virtual storyworlds while creating engaging and pedagogically effective experiences. Within these environments students actively participate in problem-solving activities. A significant challenge posed by narrative-centered learning environments is devising accurate models of narrative-centered tutorial decision making to craft customized story-based learning experiences for students. A promising approach is developing empirically driven models of narrative-centered tutorial decision-making. In this work, a dynamic Bayesian network has been designed to make narrative-centered tutorial decisions. The network parameters were learned from a corpus collected in a Wizard-of-Oz study in which narrative and tutorial planning activities were performed by humans. The performance of the resulting model was evaluated with respect to predictive accuracy and yields encouraging results. PY - 2011/// DO - 10.1007/978-3-642-21869-9_23 SP - 163-170 OP - PB - Springer Berlin Heidelberg SN - 9783642218682 9783642218699 UR - http://dx.doi.org/10.1007/978-3-642-21869-9_23 DB - Crossref ER - TY - CHAP TI - Modeling Confusion: Facial Expression, Task, and Discourse in Task-Oriented Tutorial Dialogue AU - Grafsgaard, Joseph F. AU - Boyer, Kristy Elizabeth AU - Phillips, Robert AU - Lester, James C. T2 - Lecture Notes in Computer Science AB - Recent years have seen a growing recognition of the importance of affect in learning. Efforts are being undertaken to enable intelligent tutoring systems to recognize and respond to learner emotion, but the field has not yet seen the emergence of a fully contextualized model of learner affect. This paper reports on a study of learner affect through an analysis of facial expression in human task-oriented tutorial dialogue. It extends prior work through in-depth analyses of a highly informative facial action unit and its interdependencies with dialogue utterances and task structure. The results demonstrate some ways in which learner facial expressions are dependent on both dialogue and task context. The findings also hold design implications for affect recognition and tutorial strategy selection within tutorial dialogue systems. PY - 2011/// DO - 10.1007/978-3-642-21869-9_15 SP - 98-105 OP - PB - Springer Berlin Heidelberg SN - 9783642218682 9783642218699 UR - http://dx.doi.org/10.1007/978-3-642-21869-9_15 DB - Crossref ER - TY - CHAP TI - Defending against Sybil Nodes in BitTorrent AU - So, Jung Ki AU - Reeves, Douglas S. T2 - NETWORKING 2011 AB - BitTorrent and its derivatives contribute a major portion of Internet traffic due to their simple and scalable operation. However, the lack of security mechanisms makes them vulnerable to attacks such as file piece pollution, connection slot consumption, and bandwidth exhaustion. These effects are made worse by the ability of attackers to manufacture new identities, or Sybil nodes, at will. The net effect of Sybil nodes and weak security leads to inefficient BitTorrent operation, or collapse. In this paper, we present defenses against threats from Sybil attackers in BitTorrent. A simple, direct reputation scheme called GOLF fosters peer cooperation to exclude potential attackers. Locality filtering tentatively identifies Sybil nodes based on patterns in IP addresses. Under the proposed scheme, Sybil attackers may still continue malicious behaviors, but their effect sharply decreases. Comparison to existing reputation models shows GOLF effectively detects and blocks potential attackers, despite false accusation. PY - 2011/// DO - 10.1007/978-3-642-20798-3_3 SP - 25-39 OP - PB - Springer Berlin Heidelberg SN - 9783642207976 9783642207983 UR - http://dx.doi.org/10.1007/978-3-642-20798-3_3 DB - Crossref ER - TY - JOUR TI - CAUSES OF FOURTH AGED PATIENTS HOSPITALIZATION IN AN INTERNAL MEDICINE HOSPITAL CLINIC AU - Bristianou, Magdalini AU - Panou, Charalambos AU - Chatzidakis, Ioannis AU - Tsiligrou, Vaina AU - Theodosopoulos, Ioannis AU - Rouskas, Georgios AU - Liaskoni, Constantina AU - Lanaras, Leonidas T2 - European Journal of Internal Medicine DA - 2011/10// PY - 2011/10// DO - 10.1016/S0953-6205(11)60442-1 VL - 22 SP - S108-S109 J2 - European Journal of Internal Medicine LA - en OP - SN - 0953-6205 UR - http://dx.doi.org/10.1016/S0953-6205(11)60442-1 DB - Crossref ER - TY - JOUR TI - Elsevier OSN is Sad to Announce the Loss of Fabio Neri, co-Editor-in-Chief of the Journal, Distinguished Professor and Researcher AU - Bianco, Andrea AU - Jukan, Admela AU - Rouskas, George T2 - Optical Switching and Networking DA - 2011/12// PY - 2011/12// DO - 10.1016/j.osn.2011.09.001 VL - 8 IS - 4 SP - 286-287 J2 - Optical Switching and Networking LA - en OP - SN - 1573-4277 UR - http://dx.doi.org/10.1016/j.osn.2011.09.001 DB - Crossref ER - TY - JOUR TI - On an identity of Gessel and Stanton and the new little Göllnitz identities AU - Savage, Carla D. AU - Sills, Andrew V. T2 - Advances in Applied Mathematics AB - We show that an identity of Gessel and Stanton [I. Gessel, D. Stanton, Applications of q -Lagrange inversion to basic hypergeometric series, Trans. Amer. Math. Soc. 277 (1983) 197, Eq. (7.24)] can be viewed as a symmetric version of a recent analytic variation of the little Göllnitz identities. This is significant, since the Göllnitz–Gordon identities are considered the usual symmetric counterpart to little Göllnitz theorems. Is it possible, then, that the Gessel–Stanton identity is part of an infinite family of identities like those of Göllnitz–Gordon? Toward this end, we derive partners and generalizations of the Gessel–Stanton identity. We show that the new little Göllnitz identities enumerate partitions into distinct parts in which even-indexed (resp. odd-indexed) parts are even, and derive a refinement of the Gessel–Stanton identity that suggests a similar interpretation is possible. We study an associated system of q -difference equations to show that the Gessel–Stanton identity and its partner are actually two members of a three-element family. DA - 2011/1// PY - 2011/1// DO - 10.1016/j.aam.2009.12.009 VL - 46 IS - 1-4 SP - 563-575 J2 - Advances in Applied Mathematics LA - en OP - SN - 0196-8858 UR - http://dx.doi.org/10.1016/j.aam.2009.12.009 DB - Crossref KW - Integer partitions KW - q-Series identities KW - q-Gauss summation KW - Little Gollnitz partition theorems KW - Gollnitz-Gordon partition theorem KW - Lebesgue identity ER - TY - CHAP TI - Defending Users against Smartphone Apps: Techniques and Future Directions AU - Enck, William T2 - Information Systems Security AB - Smartphone security research has become very popular in response to the rapid, worldwide adoption of new platforms such as Android and iOS. Smartphones are characterized by their ability to run third-party applications, and Android and iOS take this concept to the extreme, offering hundreds of thousands of “apps” through application markets. In response, smartphone security research has focused on protecting users from apps. In this paper, we discuss the current state of smartphone research, including efforts in designing new OS protection mechanisms, as well as performing security analysis of real apps. We offer insight into what works, what has clear limitations, and promising directions for future research. PY - 2011/// DO - 10.1007/978-3-642-25560-1_3 SP - 49-70 OP - PB - Springer Berlin Heidelberg SN - 9783642255595 9783642255601 UR - http://dx.doi.org/10.1007/978-3-642-25560-1_3 DB - Crossref ER - TY - JOUR TI - A control system testbed to validate critical infrastructure protection concepts AU - Morris, Thomas AU - Srivastava, Anurag AU - Reaves, Bradley AU - Gao, Wei AU - Pavurapu, Kalyan AU - Reddi, Ram T2 - International Journal of Critical Infrastructure Protection AB - This paper describes the Mississippi State University SCADA Security Laboratory and Power and Energy Research laboratory. This laboratory combines model control systems from multiple critical infrastructure industries to create a testbed with functional physical processes controlled by commercial hardware and software over common industrial control system routable and non-routable networks. Laboratory exercises, functional demonstrations, and lecture material from the testbed have been integrated into a newly developed industrial control system cybersecurity course, into multiple other engineering and computer science courses, and into a series of short courses targeted to industry. Integration into the classroom allows the testbed to provide a workforce development function, prepares graduate students for research activities, and raises the profile of this research area with students. The testbed enables a research process in which cybersecurity vulnerabilities are discovered, exploits are used to understand the implications of the vulnerability on controlled physical processes, identified problems are classified by criticality and similarities in type and effect, and finally cybersecurity mitigations are developed and validated against within the testbed. Overviews of research enabled by the testbed are provided, including descriptions of software and network vulnerability research, a description of forensic data logger capability developed using the testbed to retrofit existing serial port MODBUS and DNP3 devices, and a description of intrusion detection research which leverages unique characteristics of industrial control systems. DA - 2011/8// PY - 2011/8// DO - 10.1016/j.ijcip.2011.06.005 VL - 4 IS - 2 SP - 88-103 J2 - International Journal of Critical Infrastructure Protection LA - en OP - SN - 1874-5482 UR - http://dx.doi.org/10.1016/j.ijcip.2011.06.005 DB - Crossref KW - Testbed KW - Industrial control system KW - SCADA KW - Smart grid KW - Cybersecurity ER - TY - JOUR TI - From SPARQL to MapReduce: The Journey Using a Nested TripleGroup Algebra AU - Kim, HyeongSik AU - Ravindra, Padmashree AU - Anyanwu, Kemafor T2 - Proc. VLDB Endow. DA - 2011/// PY - 2011/// VL - 4 IS - 12 SP - 1426-1429 UR - http://www.vldb.org/pvldb/vol4/p1426-kim.pdf ER - TY - CHAP TI - Efficiently Evaluating Skyline Queries on RDF Databases AU - Chen, Ling AU - Gao, Sidan AU - Anyanwu, Kemafor T2 - The Semanic Web: Research and Applications AB - Skyline queries are a class of preference queries that compute the pareto-optimal tuples from a set of tuples and are valuable for multi-criteria decision making scenarios. While this problem has received significant attention in the context of single relational table, skyline queries over joins of multiple tables that are typical of storage models for RDF data has received much less attention. A naïve approach such as a join-first-skyline-later strategy splits the join and skyline computation phases which limit opportunities for optimization. Other existing techniques for multi-relational skyline queries assume storage and indexing techniques that are not typically used with RDF which would require a preprocessing step for data transformation. In this paper, we present an approach for optimizing skyline queries over RDF data stored using a vertically partitioned schema model. It is based on the concept of a “Header Point” which maintains a concise summary of the already visited regions of the data space. This summary allows some fraction of non-skyline tuples to be pruned from advancing to the skyline processing phase, thus reducing the overall cost of expensive dominance checks required in the skyline phase. We further present more aggressive pruning rules that result in the computation of near-complete skylines in significantly less time than the complete algorithm. A comprehensive performance evaluation of different algorithms is presented using datasets with different types of data distributions generated by a benchmark data generator. PY - 2011/// DO - 10.1007/978-3-642-21064-8_9 SP - 123-138 OP - PB - Springer Berlin Heidelberg SN - 9783642210631 9783642210648 UR - http://dx.doi.org/10.1007/978-3-642-21064-8_9 DB - Crossref ER - TY - CHAP TI - Effectively Interpreting Keyword Queries on RDF Databases with a Rear View AU - Fu, Haizhou AU - Anyanwu, Kemafor T2 - The Semantic Web – ISWC 2011 AB - Effective techniques for keyword search over RDF databases incorporate an explicit interpretation phase that maps keywords in a keyword query to structured query constructs. Because of the ambiguity of keyword queries, it is often not possible to generate a unique interpretation for a keyword query. Consequently, heuristics geared toward generating the top-K likeliest user-intended interpretations have been proposed. However, heuristics currently proposed fail to capture any user-dependent characteristics, but rather depend on database-dependent properties such as occurrence frequency of subgraph pattern connecting keywords. This leads to the problem of generating top-K interpretations that are not aligned with user intentions. In this paper, we propose a context-aware approach for keyword query interpretation that personalizes the interpretation process based on a user's query context. Our approach addresses the novel problem of using a sequence of structured queries corresponding to interpretations of keyword queries in the query history as contextual information for biasing the interpretation of a new query. Experimental results presented over DBPedia dataset show that our approach outperforms the state-of-the-art technique on both efficiency and effectiveness, particularly for ambiguous queries. PY - 2011/// DO - 10.1007/978-3-642-25073-6_13 SP - 193-208 OP - PB - Springer Berlin Heidelberg SN - 9783642250729 9783642250736 UR - http://dx.doi.org/10.1007/978-3-642-25073-6_13 DB - Crossref ER - TY - CHAP TI - An Intermediate Algebra for Optimizing RDF Graph Pattern Matching on MapReduce AU - Ravindra, Padmashree AU - Kim, HyeongSik AU - Anyanwu, Kemafor T2 - The Semanic Web: Research and Applications AB - Existing MapReduce systems support relational style join operators which translate multi-join query plans into several Map-Reduce cycles. This leads to high I/O and communication costs due to the multiple data transfer steps between map and reduce phases. SPARQL graph pattern matching is dominated by join operations, and is unlikely to be efficiently processed using existing techniques. This cost is prohibitive for RDF graph pattern matching queries which typically involve several join operations. In this paper, we propose an approach for optimizing graph pattern matching by reinterpreting certain join tree structures as grouping operations. This enables a greater degree of parallelism in join processing resulting in more “bushy” like query execution plans with fewer Map-Reduce cycles. This approach requires that the intermediate results are managed as sets of groups of triples or TripleGroups. We therefore propose a data model and algebra - Nested TripleGroup Algebra for capturing and manipulating TripleGroups. The relationship with the traditional relational style algebra used in Apache Pig is discussed. A comparative performance evaluation of the traditional Pig approach and RAPID+ (Pig extended with NTGA) for graph pattern matching queries on the BSBM benchmark dataset is presented. Results show up to 60% performance improvement of our approach over traditional Pig for some tasks. PY - 2011/// DO - 10.1007/978-3-642-21064-8_4 SP - 46-61 OP - PB - Springer Berlin Heidelberg SN - 9783642210631 9783642210648 UR - http://dx.doi.org/10.1007/978-3-642-21064-8_4 DB - Crossref ER - TY - CONF TI - CoSi AB - The demo will present CoSi, a system that enables context-sensitive interpretation of keyword queries on RDF databases. The techniques for representing, managing and exploiting query history are central to achieving this objective. The demonstration will show the effectiveness of our approach for capturing a user's querying context from their query history. Further, it will show how context is utilized to influence the interpretation of a new query. The demonstration is based on DBPedia, the RDF representation of Wikipedia. C2 - 2011/// C3 - Proceedings of the 20th international conference companion on World wide web - WWW '11 DA - 2011/// DO - 10.1145/1963192.1963291 UR - http://dx.doi.org/10.1145/1963192.1963291 ER - TY - BOOK TI - Learning by teaching simstudent - Interactive event AU - Matsuda, N. AU - Keiser, V. AU - Raizada, R. AU - Stylianides, G. AU - Cohen, W.W. AU - Koedinger, K.R. AB - SimStudent is an educational software infrastructure which is designed to leverage the tutor effect in an on-line learning environment. Tutor effect is the phenomenon that students learn when they teach others. SimStudent allows students to learn by teaching a computer agent instead of their peers. SimStudent is a lively computer agent that inductively learns skills through its own tutored-problem solving experience. SimStudent is integrated into an on-line learning environment where students can interactively tutor SimStudent in how to solve equations [1]. DA - 2011/// PY - 2011/// DO - 10.1007/978-3-642-21869-9_124 VL - 6738 LNAI SE - 623 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959303781&partnerID=MN8TOARS ER - TY - BOOK TI - Learning by teaching simstudent - An initial classroom baseline study comparing with cognitive tutor AU - Matsuda, N. AU - Yarzebinski, E. AU - Keiser, V. AU - Raizada, R. AU - Stylianides, G.J. AU - Cohen, W.W. AU - Koedinger, K.R. AB - This paper describes an application of a machine-learning agent, SimStudent, as a teachable peer learner that allows a student to learn by teaching. SimStudent has been integrated into APLUS (Artificial Peer Learning environment Using SimStudent), an on-line game-like learning environment. The first classroom study was conducted in local public high schools to test the effectiveness of APLUS for learning linear algebra equations. In the study, learning by teaching (i.e., APLUS) was compared with learning by tutored-problem solving (i.e., Cognitive Tutor). The results show that the prior knowledge has a strong influence on tutor learning – for students with insufficient training on the target problems, learning by teaching may have limited benefits compared to learning by tutored problem solving. It was also found that students often use inappropriate problems to tutor SimStudent that did not effectively facilitate the tutor learning. DA - 2011/// PY - 2011/// DO - 10.1007/978-3-642-21869-9_29 VL - 6738 LNAI SE - 213-221 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959316637&partnerID=MN8TOARS ER - TY - CONF TI - A machine learning approach for automatic student model discovery AU - Li, N. AU - Matsuda, N. AU - Cohen, W.W. AU - Koedinger, K.R. C2 - 2011/// C3 - EDM 2011 - Proceedings of the 4th International Conference on Educational Data Mining DA - 2011/// SP - 31-40 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84863408562&partnerID=MN8TOARS ER - TY - JOUR TI - A mathematical analysis of the R-MAT random graph generator AU - Groër, Chris AU - Sullivan, Blair D. AU - Poole, Steve T2 - Networks AB - Abstract The R‐MAT graph generator introduced by Chakrabarti et al (Int Conf Data Mining, 2004) offers a simple, fast method for generating very large directed graphs. These properties have made it a popular choice as a method of generating graphs for objects of study in a variety of disciplines, from social network analysis to high performance computing. We analyze the graphs generated by R‐MAT and model the generator in terms of occupancy problems to prove results about the degree distributions of these graphs. We prove that the limiting degree distributions can be expressed as a mixture of normal distributions with means and variances that can be easily calculated from the R‐MAT parameters. Additionally, this article offers an efficient computational technique for computing the exact degree distribution and concise expressions for a number of properties of R‐MAT graphs. ©2011 Wiley Periodicals, Inc. * . NETWORKS, 2011 DA - 2011/4/5/ PY - 2011/4/5/ DO - 10.1002/net.20417 VL - 58 IS - 3 SP - 159-170 J2 - Networks LA - en OP - SN - 0028-3045 UR - http://dx.doi.org/10.1002/net.20417 DB - Crossref KW - random graph KW - scale-free graph KW - R-MAT generator KW - occupancy problem ER - TY - CHAP TI - Leveraging Card-Based Collaborative Activities as Culturally Situated Design Tools AU - McCrickard, D. Scott AU - Townsend, DeMarcus AU - Winchester, Woodrow W. AU - Barnes, Tiffany T2 - Communications in Computer and Information Science AB - This paper describes two examples of virtual card games serving as Culturally Situated Design Tools (CSDTs) for young people. CSDTs have promise in helping people to learn by connecting principles from computing with aspects of their heritage or gender. The development and deployment of card games on two cutting-edge platforms (mobile devices and multitouch tables) revealed novel ways to display information to users and important lessons for deploying them to young people. PY - 2011/// DO - 10.1007/978-3-642-22098-2_47 SP - 232-236 OP - PB - Springer Berlin Heidelberg SN - 9783642220975 9783642220982 UR - http://dx.doi.org/10.1007/978-3-642-22098-2_47 DB - Crossref ER - TY - CHAP TI - Experimental Evaluation of Automatic Hint Generation for a Logic Tutor AU - Stamper, John C. AU - Eagle, Michael AU - Barnes, Tiffany AU - Croy, Marvin T2 - Lecture Notes in Computer Science AB - In our prior work we showed it was feasible to augment a logic tutor with a data-driven Hint Factory that uses data to automatically generate context-specific hints for an existing computer aided instructional tool. Here we investigate the impact of automatically generated hints on educational outcomes in a robust experiment that shows that hints help students persist in deductive logic courses. Three instructors taught two semester-long courses, each teaching one semester using a logic tutor with hints, and one semester using the tutor without hints, controlling for the impact of different instructors on course outcomes. Our results show that students in the courses using a logic tutor augmented with automatically generated hints attempted and completed significantly more logic proof problems, were less likely to abandon the tutor, and performed significantly better on a post-test implemented within the tutor. PY - 2011/// DO - 10.1007/978-3-642-21869-9_45 SP - 345-352 OP - PB - Springer Berlin Heidelberg SN - 9783642218682 9783642218699 UR - http://dx.doi.org/10.1007/978-3-642-21869-9_45 DB - Crossref ER - TY - CONF TI - GameChanger AU - Payton, Jamie AU - Powell, Evie AU - Nickel, Andrea AU - Doran, Katelyn AU - Barnes, Tiffany T2 - Proceeding of the 1st international workshop AB - While the health benefits of exercise are wide-ranging and wellknown, the population of the United States is suffering from a lack of physical activity. We believe that combining elements of social interaction with exercise in video games will lead to increased and sustained engagement in physical activity. In this paper, we present an initial design of GameChanger, a middleware to support the development of a new generation of social exergames that interweave physical activity as a core game mechanic with social elements such as competition and collaboration. The GameChanger middleware provides programming abstractions that are specific to social exergame mechanics, elevating their description so that even non-expert programmers can create interesting social exergames that utilize mobile phones and sensing technology to integrate physical activity into gameplay. In addition, the middleware provides constructs for performing continuous assessment of physical activity during gameplay; these constructs can be used to provide feedback to the gameplayer or to collect datasets for evaluation by health researchers. As such, the GameChanger middleware can also serve as a platform to support scientific experimentation and exploration to determine which combinations of social and physical elements have the greatest impact on physical activity. C2 - 2011/// C3 - Proceeding of the 1st international workshop on Games and software engineering - GAS '11 DA - 2011/// DO - 10.1145/1984674.1984688 PB - ACM Press SN - 9781450305785 UR - http://dx.doi.org/10.1145/1984674.1984688 DB - Crossref ER - TY - CONF TI - Experimental evaluation of BeadLoom game AU - Boyce, Acey Kreisler AU - Campbell, Antoine AU - Pickford, Shaun AU - Culler, Dustin AU - Barnes, Tiffany T2 - the 16th annual joint conference AB - The Virtual Bead Loom (VBL) is a Culturally Situated Design Tool that successfully teaches students middle school math concepts while they learn about and create their own Native American bead artifacts. We developed BeadLoom Game to augment VBL with game elements that encourage players to apply the computational thinking skills of iteration and layering while optimizing the number of steps they take to solve a puzzle. In our prior work, we showed that BeadLoom Game is effective at teaching Cartesian coordinates, iteration, and layering. In this study, we use a switching replications experimental design to compare performance of BeadLoom Game with the VBL. Our results from two summer camps, one for middle school and one for college-bound high school students, show that through the addition of game based objectives, BeadLoom Game teaches Cartesian coordinates as well as the VBL but also teaches the computational thinking practices of iteration and layering. C2 - 2011/// C3 - Proceedings of the 16th annual joint conference on Innovation and technology in computer science education - ITiCSE '11 DA - 2011/// DO - 10.1145/1999747.1999816 PB - ACM Press SN - 9781450306973 UR - http://dx.doi.org/10.1145/1999747.1999816 DB - Crossref ER - TY - CONF TI - BeadLoom Game AU - Boyce, Acey AU - Doran, Katelyn AU - Campbell, Antoine AU - Pickford, Shaun AU - Culler, Dustin AU - Barnes, Tiffany T2 - the 6th International Conference AB - BeadLoom Game (BLG) is an educational puzzle game designed to teach students basic Cartesian coordinates, iteration, and layering. Although this game has been proven to be successful at teaching students these concepts, many participants reported wanting more competitive and free-play creative elements in the game. In response, we augmented the BeadLoom Game with a competitive high score table, a creative custom puzzle mode, and a social network framework. Here we report results of an experiment where middle school students are given versions of the BLG with different combinations of these new features. Based on the in-game metrics and player surveys we show that while both the competitive and the creative game modes increase a majority of the player's motivation it is not until we add both features that we maximize this effect. Through a combination of creative and competitive game modes we are able to have the highest motivation for the largest number of different players. C2 - 2011/// C3 - Proceedings of the 6th International Conference on Foundations of Digital Games - FDG '11 DA - 2011/// DO - 10.1145/2159365.2159384 PB - ACM Press SN - 9781450308045 UR - http://dx.doi.org/10.1145/2159365.2159384 DB - Crossref ER - TY - CONF TI - Snag'em: Creating Community Connections through Games AU - Powell, Evie AU - Stukes, Felesia AU - Barnes, Tiffany AU - Lipford, Heather Richter T2 - 2011 IEEE Third Int'l Conference on Privacy, Security, Risk and Trust (PASSAT) / 2011 IEEE Third Int'l Conference on Social Computing (SocialCom) AB - It is difficult for new community members to make the connections that would be most beneficial to them - connections with seasoned members of the community, or members of other groups. To address this problem, we have created Snag'em, a web-based social networking game that helps people create, monitor, and strengthen connections with one another. In contrast to existing social games, Snag'em facilitates offline interaction to create an online social network. This paper discusses the design of Snag'em, the use of game mechanics to engage academic community members in social interaction, and the results of two preliminary studies along with the design implications of each. C2 - 2011/10// C3 - 2011 IEEE Third Int'l Conference on Privacy, Security, Risk and Trust and 2011 IEEE Third Int'l Conference on Social Computing DA - 2011/10// DO - 10.1109/passat/socialcom.2011.229 PB - IEEE SN - 9781457719318 9780769545783 UR - http://dx.doi.org/10.1109/passat/socialcom.2011.229 DB - Crossref ER - TY - CONF TI - Social user generated content's effect on creativity in educational games AU - Boyce, Acey AU - Doran, Katie AU - Campbell, Antoine AU - Pickford, Shaun AU - Culler, Dustin AU - Barnes, Tiffany T2 - the 8th ACM conference AB - BeadLoom Game (BLG) is an educational puzzle game developed by adding game elements to a free-play educational tool called the Virtual Bead Loom (VBL). To motivate students who prefer the creative freedom of VBL, we added Custom Puzzle mode to BLG so players can create, share, and rate user-generated puzzles. We compare VBL and BLG Custom Puzzles to show that this mode increases the creativity and complexity of student work. C2 - 2011/// C3 - Proceedings of the 8th ACM conference on Creativity and cognition - C&C '11 DA - 2011/// DO - 10.1145/2069618.2069675 PB - ACM Press SN - 9781450308205 UR - http://dx.doi.org/10.1145/2069618.2069675 DB - Crossref ER - TY - JOUR TI - The STARS Alliance AU - Dahlberg, Teresa AU - Barnes, Tiffany AU - Buch, Kim AU - Rorrer, Audrey T2 - ACM Transactions on Computing Education AB - The Students and Technology in Academia, Research, and Service (STARS) Alliance is a nationally-connected system of regional partnerships among higher education, K-12 schools, industry and the community with a mission to broaden the participation of women, under-represented minorities and persons with disabilities in computing (BPC). Each regional partnership is led by a STARS member college or university with partners such as local chapters of the Girl Scouts, the Black Data Processors Association, public libraries, Citizen Schools, and companies that employ computing graduates. STARS goals include retaining and graduating undergraduates and recruiting and bridging undergraduates into graduate programs. The alliance works toward these goals through activities that advance the central values of Technical Excellence, Leadership, Community, and Service and Civic Engagement. In particular, all STARS college and university members implement the STARS Leadership Corps ( SLC ), an innovative model for enveloping a diverse set of BPC practices within a common framework for implementation within multiple organizations, common assessment, and sustainability through curricula integration. Herein, we describe the SLC model and its implementation in the STARS schools, including details of an SLC service-learning course that has been adopted by eight STARS schools. We report the results of our three-year study of the SLC in the 20 STARS schools. Our study found a positive effect of participation in the SLC on important student success variables, including self-efficacy, perceived social relevance of computing, grade point average, and commitment to remain in computing. Results indicate that the SLC model is effective for students under-represented in computing, as well as for those not from under-represented groups. DA - 2011/10/1/ PY - 2011/10/1/ DO - 10.1145/2037276.2037282 VL - 11 IS - 3 SP - 1-25 J2 - TOCE LA - en OP - SN - 1946-6226 UR - http://dx.doi.org/10.1145/2037276.2037282 DB - Crossref ER - TY - JOUR TI - Learning Cultural Conversational Protocols with Immersive Interactive Virtual Humans AU - Babu, Sabarish V. AU - Suma, Evan AU - Hodges, Larry F. AU - Barnes, Tiffany T2 - International Journal of Virtual Reality AB - This paper reports on a study conducted to investi-gate the effects of using immersive virtual humans in natural multi-modal interaction to teach users cultural conversational verbal and non-verbal protocols in south Indian culture. The study was conducted using a between-subjects experimental design. We compared instruction and interactive feedback from immersive virtual humans against instruction based on a written study guide with illustrations of the cultural protocols. Partici-pants were then tested on how well they learned the cultural conversational protocols by exercising the cultural conventions in front of videos of real people. Subjective evaluations of participants' performance was conducted by three south Indian reviewers who were blind to the condition the participants were assigned. Objective evaluations of participants' performance were conducted on the motion tracking log data recorded during the testing session. We also measured the participants' pre and post positive and negative affect of training in both conditions, as well as the effect of co-presence with the life-size virtual south Indians. The results of our subjective evaluation suggest that participants who trained with the virtual humans performed significantly better than the participants who studied from literature. The results also revealed that there were no significant differences in positive or negative affect between conditions. However, overall for all participants in both conditions, positive affect increased and negative affect decreased from before to after instruction. DA - 2011/1/1/ PY - 2011/1/1/ DO - 10.20870/ijvr.2011.10.4.2826 VL - 10 IS - 4 SP - 25-35 J2 - IJVR OP - SN - 1081-1451 UR - http://dx.doi.org/10.20870/ijvr.2011.10.4.2826 DB - Crossref ER - TY - CONF TI - Beating the spread AU - Miller, Gary L. AU - Phillips, Todd AU - Sheehy, Donald R. T2 - the 27th annual ACM symposium AB - We present NetMesh, a new algorithm that produces a conforming Delaunay mesh for point sets in any fixed dimension with guaranteed optimal mesh size and quality. Our comparison-based algorithm runs in O(n log n + m) time, where n is the input size and m is the output size, and with constants depending only on the dimension and the desired element quality. It can terminate early in O(n log n) time returning a O(n) size Voronoi diagram of a superset of P, which again matches the known lower bounds. C2 - 2011/// C3 - Proceedings of the 27th annual ACM symposium on Computational geometry - SoCG '11 DA - 2011/// DO - 10.1145/1998196.1998252 PB - ACM Press SN - 9781450306829 UR - http://dx.doi.org/10.1145/1998196.1998252 DB - Crossref ER - TY - CONF TI - Trust as Dependence: A Logical Approach AU - Singh, Munindar P. T2 - International Conference on Autonomous Agents and Multiagent Systems C2 - 2011/5// C3 - AAMAS '11: Proceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems CY - Taipei, Taiwan DA - 2011/5// PY - 2011/5/2/ VL - 2 SP - 863–870 PB - IFAAMAS UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899408581&partnerID=MN8TOARS ER - TY - CONF TI - Specifying and Applying Commitment-Based Business Patterns AU - Chopra, Amit K. AU - Singh, Munindar P. T2 - International Conference on Autonomous Agents and Multiagent Systems C2 - 2011/5// C3 - AAMAS '11: Proceedings of the 10th International Conference on Autonomous Agents and Multiagent Systems CY - Taipei, Taiwan DA - 2011/5// PY - 2011/5/2/ VL - 1 SP - 475–482 PB - IFAAMAS UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899421820&partnerID=MN8TOARS ER - TY - CONF TI - Information-driven interaction-oriented programming: BSPL, the blindingly simple protocol language AU - Singh, M.P. C2 - 2011/// C3 - 10th International Conference on Autonomous Agents and Multiagent Systems 2011, AAMAS 2011 DA - 2011/// VL - 1 SP - 457-464 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899440400&partnerID=MN8TOARS ER - TY - CONF TI - Kokomo: An empirically evaluated methodology for affective applications AU - Sollenberger, Derek J. AU - Singh, Munindar P. T2 - International Conference on Autonomous Agents and MultiAgent Systems C2 - 2011/5// C3 - Proceedings of the 10th International Conference on Autonomous Agents and MultiAgent Systems (AAMAS) CY - Taipei, Taiwan DA - 2011/5// PY - 2011/5// VL - 1 SP - 293–300 PB - IFAAMAS UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899438815&partnerID=MN8TOARS ER - TY - BOOK TI - Formal methods in agent-oriented software engineering AU - El Fallah-Seghrouchni, A. AU - Gomez-Sanz, J.J. AU - Singh, M.P. AB - There is a growing interest among agent and multiagent system developers for formal methods. Formal methods are means to define and realize correct specifications of multiagent system. The benefits of formal methods become clearer when we recognize the cost of developing a defective multiagent system. This paper seeks to introduce engineers to the possibilities of applying formal methods for multiagent systems. To this end, it discusses selected formal methods approaches for multiagent systems for which there is tool support. These works have been organized into two broad categories: those formal methods constituting a development method in themselves and those intended to complement an existing development method. DA - 2011/// PY - 2011/// DO - 10.1007/978-3-642-19208-1_15 VL - 6038 LNCS SE - 213-228 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952420920&partnerID=MN8TOARS ER - TY - CONF TI - Commitments with regulations: Reasoning about safety and control in REGULA AU - Marengo, E. AU - Baldoni, M. AU - Baroglio, C. AU - Chopra, A.K. AU - Patti, V. AU - Singh, M.P. C2 - 2011/// C3 - 10th International Conference on Autonomous Agents and Multiagent Systems 2011, AAMAS 2011 DA - 2011/// VL - 1 SP - 433-440 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84899444781&partnerID=MN8TOARS ER - TY - BOOK TI - Methodology for engineering affective social applications AU - Sollenberger, D.J. AU - Singh, M.P. AB - Affective applications are becoming increasingly mainstream in entertainment and education. Yet, current techniques for building such applications are limited, and the maintenance and use of affect is in essence handcrafted in each application. The Koko architecture describes middleware that reduces the burden of incorporating affect into applications, thereby enabling developers to concentrate on the functional and creative aspects of their applications. Further, Koko includes a methodology for creating affective social applications, called Koko-ASM. Specifically, it incorporates expressive communicative acts, and uses them to guide the design of an affective social application. With respect to agent-oriented software engineering, Koko contributes a methodology that incorporates expressives. The inclusion of expressives, which are largely ignored in conventional approaches, expands the scope of AOSE to affective applications. DA - 2011/// PY - 2011/// DO - 10.1007/978-3-642-19208-1_7 VL - 6038 LNCS SE - 97-109 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79952381410&partnerID=MN8TOARS ER - TY - CONF TI - LoST: Local State Transfer: An architectural style for the distributed enactment of business protocols AU - Singh, M.P. AB - Local State Transfer (LoST) is a simple, declarative approach for enacting communication protocols. LoST is perfectly distributed and relies only upon the local knowledge of each business partner. It involves a novel treatment of the information bases of protocols, especially in terms of how their parameters are specified. As a result, LoST can capture subtle patterns of interaction that more complex approaches cannot handle well. Further, LoST lends itself to implementations that are robust against unordered and lossy message transmission. C2 - 2011/// C3 - Proceedings - 2011 IEEE 9th International Conference on Web Services, ICWS 2011 DA - 2011/// DO - 10.1109/ICWS.2011.48 SP - 57-64 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80053159719&partnerID=MN8TOARS ER - TY - BOOK TI - Analyzing contract robustness through a model of commitments AU - Chopra, A.K. AU - Oren, N. AU - Modgil, S. AU - Desai, N. AU - Miles, S. AU - Luck, M. AU - Singh, M.P. AB - We address one of the challenges in developing solutions based on multiagent systems for the problems of cross-organizational business processes and commerce generally. Specifically, we study how to gather and analyze requirements embodied within business contracts using the abstractions from multiagent systems. Commerce is driven by business contracts. Each party to a business contract must be assured that the contract is robust, in the sense that it fulfills its goals and avoids undesirable outcomes. However, real-life business contracts tend to be complex and unamenable both to manual scrutiny and domain-independent scientific methods, making it difficult to provide automated support for determining or improving their robustness. As a result, establishing a contract is nontrivial and adds significantly to the transaction costs of conducting business. If the adoption of multiagent systems approaches in supporting business interactions is to be viable, we need to develop appropriate techniques to enable tools to reason about contracts in relation to their robustness. To this end, we propose a powerful approach to assessing the robustness of contracts, and make two main contributions. First, we demonstrate a novel conceptual model for contracts that is based on commitments. Second, we offer a methodology for (i) creating commitment-based models of contracts from textual descriptions, and (ii) evaluating the contract models for robustness. We validate these contributions via a study of real-world contracts. DA - 2011/// PY - 2011/// DO - 10.1007/978-3-642-22636-6_2 VL - 6788 LNCS SE - 17-36 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80054108244&partnerID=MN8TOARS ER - TY - CONF TI - Colaba: Collaborative design of cross-organizational processes AU - Chopra, A.K. AU - Singh, M.P. AB - Cross-organizational processes naturally involve multiple stakeholders with distinct business interests. Yet, current process modeling approaches are conceptually centralized. This paper develops Colaba, a novel approach for the design of a cross-organizational process. Colaba naturally accommodates the requirements of multiple stakeholders. It is realized as a tool and methodology that uses and maintains a repository of business protocols, each describing a business function to the desired level of nuance. Design in Colaba is thus simply a matter of selecting, refining, extending, and composing protocols. Colaba is based on the concepts of Issue-Based Information Systems. It naturally supports stakeholders proposing process models, raising issues about them, and evaluating alternative proposals. Colaba contributes argumentation primitives and a representation relevant to business processes that accommodates the diverse perspectives of the roles in a protocol. This paper includes an evaluation of Colaba via a case study. C2 - 2011/// C3 - 2011 Workshop on Requirements Engineering for Systems, Services and Systems-of-Systems, RESS 2011 - Workshop Co-located with the 19th IEEE International Requirements Engineering Conference DA - 2011/// DO - 10.1109/RESS.2011.6043928 SP - 36-43 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80055038648&partnerID=MN8TOARS ER - TY - CONF TI - An Ontology-based method and tool for cross-domain requirements visualization AU - Ajmeri, Nirav AU - Vidhani, Kumar AU - Bhat, Manoj AU - Ghaisas, Smita A2 - Maalej, Walid A2 - Thurimella, Anil Kumar AB - The complexity associated with understanding the cross-domain scope of a requirement has always been a challenge. Requirement Analysts use their experience in determining the functional scope boundaries of requirements. However, chances of missing out key concepts in domains peripheral to the domain of interest are quite high. Ontologies are increasingly becoming the standard way of representing shared understanding of a domain and their use in understanding and visualizing the cross-domain scope of requirements can be a step towards improving the completeness of requirements. We present a method - based on ontology mapping technique, and an assisting tool that would help Requirement Analysts visualize - how requirements span across multiple domains. C2 - 2011/// C3 - 2011 4th International Workshop on Managing Requirements Knowledge, MaRK'11 - Part of the 19th IEEE International Requirements Engineering Conference, RE'11 CY - United States DA - 2011/// DO - 10.1109/MARK.2011.6046558 SP - 22-23 PB - IEEE UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-80555133306&partnerID=MN8TOARS ER - TY - CONF TI - Intelligent informatics platform for nano-agriculture AU - Rose, Preethu AU - Bhat, Manoj AU - Vidhani, Kumar AU - Ajmeri, Nirav AU - Gole, Anand AU - Ghaisas, Smita AB - The application of nanotechnology in the agricultural sector is likely to facilitate and frame the next stage of development of genetically modified crops, precision farming techniques (remote and local sensing), remediation (water treatment plants, pesticide removal from ground water), nano-sensors, nano-agricultural chemicals and most importantly designing smart delivery systems for nutrients and pesticides[1]. Although most of these applications are still in their infancy, they have a great potential to revolutionalize the entire agricultural value chain [2]. The wide spectrum of applications has resulted into emergence of multiple stakeholders such as nano-agriculture researchers, practitioners (agriculturists/ farmers), manufacturers and regulatory bodies. They would be seeking and using knowledge in this nascent area from different perspectives such as research and technology, consumer safety, environmental impact and ethical, legal and social implications. No informatics platform exists to cater to the knowledge needs of various stakeholders in this field. To address this gap, we have developed an intelligent Nano-Agriculture Informatics System (NAIS), wherein these stakeholders can carry out multiple activities of their interest. NAIS incorporates a collaborative and semantically guided process to facilitate knowledge-based activities. C2 - 2011/// C3 - Proceedings of the IEEE Conference on Nanotechnology DA - 2011/// DO - 10.1109/NANO.2011.6144536 SP - 916-919 PB - IEEE UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84858984936&partnerID=MN8TOARS ER - TY - CONF TI - Quadratic-time certificates in linear algebra AU - Kaltofen, Erich L. AU - Nehring, Michael AU - Saunders, B. David T2 - the 36th international symposium AB - We present certificates for the positive semidefiniteness of an n by n matrix A, whose entries are integers of binary length log ||A||, that can be verified in O(n(2+µ) (log ||A||)(1+µ) binary operations for any µ > 0. The question arises in Hilbert/Artin-based rational sum-of-squares certificates (proofs) for polynomial inequalities with rational coefficients. We allow certificates that are validated by Monte Carlo randomized algorithms, as in Rusins Freivalds's famous 1979 quadratic time certification for the matrix product. Our certificates occupy O(n(3+µ) (log ||A||)(1+µ) bits, from which the verfication algorithm randomly samples a quadratic amount. C2 - 2011/// C3 - Proceedings of the 36th international symposium on Symbolic and algebraic computation - ISSAC '11 DA - 2011/// DO - 10.1145/1993886.1993915 PB - ACM Press SN - 9781450306751 UR - http://dx.doi.org/10.1145/1993886.1993915 DB - Crossref ER - TY - CONF TI - Supersparse black box rational function interpolation AU - Kaltofen, Erich L. AU - Nehring, Michael T2 - the 36th international symposium AB - We present a method for interpolating a supersparse blackbox rational function with rational coefficients, for example, a ratio of binomials or trinomials with very high degree. We input a blackbox rational function, as well as an upper bound on the number of non-zero terms and an upper bound on the degree. The result is found by interpolating the rational function modulo a small prime p, and then applying an effective version of Dirichlet's Theorem on primes in an arithmetic progression progressively lift the result to larger primes. Eventually we reach a prime number that is larger than the inputted degree bound and we can recover the original function exactly. In a variant, the initial prime p is large, but the exponents of the terms are known modulo larger and larger factors of p-1. C2 - 2011/// C3 - Proceedings of the 36th international symposium on Symbolic and algebraic computation - ISSAC '11 DA - 2011/// DO - 10.1145/1993886.1993916 PB - ACM Press SN - 9781450306751 UR - http://dx.doi.org/10.1145/1993886.1993916 DB - Crossref ER - TY - CONF TI - Fast estimates of Hankel matrix condition numbers and numeric sparse interpolation AU - Kaltofen, Erich L. AU - Lee, Wen-shin AU - Yang, Zhengfeng T2 - the 2011 International Workshop AB - We investigate our early termination criterion for sparse polynomial interpolation when substantial noise is present in the values of the polynomial. Our criterion in the exact case uses Monte Carlo randomization which introduces a second source of error. We harness the Gohberg-Semencul formula for the inverse of a Hankel matrix to compute estimates for the structured condition numbers of all arising Hankel matrices in quadratic arithmetic time overall, and explain how false ill-conditionedness can arise from our randomizations. Finally, we demonstrate by experiments that our condition number estimates lead to a viable termination criterion for polynomials with about 20 non-zero terms and of degree about 100, even in the presence of noise of relative magnitude 10-5. C2 - 2011/// C3 - Proceedings of the 2011 International Workshop on Symbolic-Numeric Computation - SNC '11 DA - 2011/// DO - 10.1145/2331684.2331704 PB - ACM Press SN - 9781450305150 UR - http://dx.doi.org/10.1145/2331684.2331704 DB - Crossref ER - TY - ER - TY - CHAP TI - The “Seven Dwarfs” of Symbolic Computation AU - Kaltofen, Erich L. T2 - Texts & Monographs in Symbolic Computation AB - We present the Seven Dwarfs of Symbolic Computation, which are sequential and parallel algorithmic methods that today carry a great majority of all exact and hybrid symbolic compute cycles. We will elaborate on each dwarf and compare with Colella’s seven and the Berkeley team’s thirteen dwarfs of scientific computing. PY - 2011/10/12/ DO - 10.1007/978-3-7091-0794-2_5 SP - 95-104 OP - PB - Springer Vienna SN - 9783709107935 9783709107942 UR - http://dx.doi.org/10.1007/978-3-7091-0794-2_5 DB - Crossref ER - TY - CHAP TI - Cm*: The first non-uniform memory access architecture AU - Siewiorek, Daniel P. AU - Gehringer, Edward F. T2 - Encyclopedia of Parallel Computing A2 - Padua, David PY - 2011/// PB - Springer ER - TY - CONF TI - Experience with software support for managing student-authored wiki textbooks AU - Gehringer, Edward F. T2 - 2011 ASEE Annual Conference and Exposition C2 - 2011/// C3 - Proceedings of the 2011 ASEE Annual Conference and Exposition CY - Vancouver, BC DA - 2011/// PY - 2011/6/26/ PB - American Society for Engineering Education ER - TY - CONF TI - Automated Assessment of Review Quality Using Latent Semantic Analysis AU - Ramachandran, Lakshmi AU - Gehringer, Edward F. T2 - 2011 11th IEEE International Conference on Advanced Learning Technologies (ICALT) AB - Quality of a review can be identified by reviewing a review. Quantifiable factors that help identify the quality of a review include quality and tone of review comments, and the number of tokens each contains. We use machine-learning techniques such as latent semantic analysis (LSA) and cosine similarity to classify comments based on their quality and tone. Our paper details experiments that were conducted on student review and metareview data by using different data pre-processing steps. We compare these pre-processing steps and show that when applied to student review data, they help improve data quality by providing better text classification. Our technique helps predict metareview scores for student reviews. C2 - 2011/7// C3 - 2011 IEEE 11th International Conference on Advanced Learning Technologies DA - 2011/7// DO - 10.1109/icalt.2011.46 PB - IEEE SN - 9781612842097 UR - http://dx.doi.org/10.1109/icalt.2011.46 DB - Crossref ER - TY - CONF TI - Determining Degree of Relevance of Reviews Using a Graph-Based Text Representation AU - Ramachandran, Lakshmi AU - Gehringer, Edward F. T2 - 2011 IEEE 23rd International Conference on Tools with Artificial Intelligence (ICTAI) AB - Reviews are text-based feedback provided by reviewers to authors. The quality of a review can be determined by identifying how relevant it is to the work that the review was written for as well as its similarity to existing well-written and coherent reviews. Relevance between two pieces of text can be determined by identifying semantic and syntactic similarities between them. In this paper, we make use of string-based metrics that incorporate concepts of paraphrasing and plagiarism to determine matching between texts. We use a graph-based text representation technique. We use the k-nearest neighbor classification algorithm to build a supervised model and classify text as LOW, MEDIUM or HIGH based on values of the metrics. We evaluate our approach on three data sets from student assignments and show that our model achieves an average accuracy of 63%. C2 - 2011/11// C3 - 2011 IEEE 23rd International Conference on Tools with Artificial Intelligence DA - 2011/11// DO - 10.1109/ictai.2011.72 PB - IEEE SN - 9781457720680 9780769545967 UR - http://dx.doi.org/10.1109/ictai.2011.72 DB - Crossref KW - relevance KW - graph-based representation KW - plagiarism KW - paraphrasing KW - k-nearest neighbor ER - TY - JOUR TI - Lessons in public touchscreen development AU - Orphanides, Andreas K T2 - Code4lib Journal DA - 2011/// PY - 2011/// VL - 15 UR - https://journal.code4lib.org/articles/5832 ER - TY - CONF TI - Restructuring software with gestures AU - Murphy-Hill, E. AU - Ayazifar, M. AU - Black, A. P. AB - Refactoring is the process of changing the structure of code without changing its meaning, and is a frequent practice among developers. Although programmers refactor frequently, they usually do not use refactoring tools to automate this process. We argue that the need to recall the name of a refactoring before the appropriate tool can be invoked makes it unnecessarily hard to initiate a refactoring with a tool. Conventional ways of initiating a tool also make it hard to transition from novice tool user to expert tool user. The contribution of this paper is a memorable mapping from gestures to refactorings, and an implementation of that mapping in the form of marking menus. In the first reported experiment to explore the effect of the position of items in marking menus on people's ability to infer the location of those items, we asked 16 programmers to complete a paper-based evaluation of our mapping. The results suggest that programmers can infer the gesture that will invoke the appropriate refactoring tool, even if they do not know the name of the refactoring. We also illustrate how marking menus might be used for refactoring during development with two other small studies. C2 - 2011/// C3 - 2011 ieee symposium on visual languages and human-centric computing (vl/hcc 2011) DA - 2011/// DO - 10.1109/vlhcc.2011.6070394 SP - 165-172 ER - TY - CONF TI - Jamming attacks in 802.11g-a cognitive radio based approach AU - Prasad, S. AU - Thuente, D. J. AB - Wireless networks are susceptible to jamming attacks, which can severely reduce the network throughput. In this paper, we study the behavior and the performance of 802.11g networks under a hybrid jamming attack of configuring a cognitive radio as a jammer. With characteristics such as fast channel switching, quick response time and software reconfigurability, cognitive radios can be used not only to improve the spectrum sharing management, but also to act as an effective jammer. We use a single cognitive radio to simultaneously jam three networks in an energy efficient manner and also to deny any channel change protocol by the targeted network to avoid jamming. We attack the `g' band OFDM channels directly using the fast channel switching capability of the cognitive radio. The jammer sequentially senses traffic on each of the networks without being part of any network. We present the results of the jamming attacks at the MAC and physical layers. We show how the cognitive radio can dynamically adjust its attack to the traffic on each network. We evaluated the performance of three networks individually and together under intelligent and reactive jamming. C2 - 2011/// C3 - 2011 - Milcom 2011 Military Communications Conference DA - 2011/// DO - 10.1109/milcom.2011.6127467 SP - 1219-1224 ER - TY - CONF TI - From the manager's perspective: Classroom contributions to open-source projects AU - Gehringer, Edward AB - For the past several years, students in computer-science courses have been assigned work on open-source project development. The literature is replete with examples. Yet an instructor desiring to incorporate OSS into a course often has difficulty finding a suitable project and developing a fruitful interaction with its personnel. This paper reports on a survey of managers of OSS projects on how they have interacted with classes and students, and on what faculty can do to work with them effectively. Our findings indicate that instructors need to seek out projects weeks or months in advance, and need to be personally involved in OSS development themselves, and that they need to give their students a good background in design and testing. As a help for instructors looking for a project, we describe several OSS projects that have benefited from student contributions. C2 - 2011/// C3 - 2011 frontiers in education conference (fie) DA - 2011/// DO - 10.1109/fie.2011.6143028 ER - TY - JOUR TI - Efficient alpha, beta-motif finder for identification of phenotype-related functional modules AU - Schmidt, Matthew C. AU - Rocha, Andrea M. AU - Padmanabhan, Kanchana AU - Chen, Zhengzhang AU - Scott, Kathleen AU - Mihelcic, James R. AU - Samatova, Nagiza F. T2 - BMC BIOINFORMATICS AB - Microbial communities in their natural environments exhibit phenotypes that can directly cause particular diseases, convert biomass or wastewater to energy, or degrade various environmental contaminants. Understanding how these communities realize specific phenotypic traits (e.g., carbon fixation, hydrogen production) is critical for addressing health, bioremediation, or bioenergy problems.In this paper, we describe a graph-theoretical method for in silico prediction of the cellular subsystems that are related to the expression of a target phenotype. The proposed (α, β)-motif finder approach allows for identification of these phenotype-related subsystems that, in addition to metabolic subsystems, could include their regulators, sensors, transporters, and even uncharacterized proteins. By comparing dozens of genome-scale networks of functionally associated proteins, our method efficiently identifies those statistically significant functional modules that are in at least α networks of phenotype-expressing organisms but appear in no more than β networks of organisms that do not exhibit the target phenotype. It has been shown via various experiments that the enumerated modules are indeed related to phenotype-expression when tested with different target phenotypes like hydrogen production, motility, aerobic respiration, and acid-tolerance.Thus, we have proposed a methodology that can identify potential statistically significant phenotype-related functional modules. The functional module is modeled as an (α, β)-clique, where α and β are two criteria introduced in this work. We also propose a novel network model, called the two-typed, divided network. The new network model and the criteria make the problem tractable even while very large networks are being compared. The code can be downloaded from http://www.freescience.org/cs/ABClique/ DA - 2011/11/11/ PY - 2011/11/11/ DO - 10.1186/1471-2105-12-440 VL - 12 SP - SN - 1471-2105 ER - TY - CONF TI - Accountability and the use of classroom response devices AU - Gehringer, Edward AU - Narang, M. B. AB - Classroom response devices, such as clickers, have proved effective in improving student engagement during class time. We performed a study to investigate how much of this improvement was due to heightened accountability, either because students were required to take and pass a pre-quiz over the lecture material, or because students were given credit for each answer submitted. We found that the presence of a pre-quiz was associated with a much higher response rate, 38.5% vs. 29.3%. Giving credit for answering questions also boosted the response rate, from 30.3% to 43.2%. We also found that asking more questions during class tended was associated with a lower response rate. When only one question was asked, the response rate was above 60%, but if more than five questions were asked, the response rate was barely 30%. These findings suggest that accountability is important in making effective use of classroom response devices. C2 - 2011/// C3 - 2011 frontiers in education conference (fie) DA - 2011/// DO - 10.1109/fie.2011.6142866 ER - TY - CONF TI - Teaching second-level Java and software engineering with Android AU - Heckman, Sarah AU - Horton, T. B. AU - Sherriff, M. T2 - IEEE AB - Over the past two years, second-year Java and software engineering courses have been taught at the University of Virginia and North Carolina State University utilizing the Android OS platform. Instructors taught a variety of traditional second-year topics, including abstraction, design, requirements, and testing, utilizing a variety of Android-based mobile devices. Anecdotal responses from student surveys and evaluations from five course sessions indicate that teaching lower-level courses with more advanced and current technology, even with a steeper learning curve, is beneficial. In this tutorial proposal, we outline our plan for presenting a session that would help educators incorporate the Android OS into their curriculum and how to use the system even if mobile devices are not available. C2 - 2011/// C3 - 2011 24th IEEE-CS Conference on Software Engineering Education and Training (CSEET) DA - 2011/// DO - 10.1109/cseet.2011.5876144 SP - 540–542 ER - TY - CONF TI - Robustness and expression independence in 3D face recognition AU - Miao, S. AU - Krim, H. AB - We describe a robust method for 3D face recognition under variance of facial expressions. The method utilizes the identical areas on two facial images as the measurement of distance. To segment the identical area, partial shape matching is performed using closest point registration and level set method. The segmentation problem is formalized into an Eikonal equation, which can be efficiently solved by fast marching method. The presented 3D face recognition method shows a very promising recognition rate. C2 - 2011/// C3 - 2011 ieee workshop on signal processing systems (sips) DA - 2011/// DO - 10.1109/sips.2011.6088991 SP - 289-292 ER - TY - JOUR TI - ELT: Efficient Log-based Troubleshooting System for Cloud Computing Infrastructures AU - Kc, Kamal AU - Gu, Xiaohui T2 - 2011 30TH IEEE INTERNATIONAL SYMPOSIUM ON RELIABLE DISTRIBUTED SYSTEMS (SRDS) AB - We present an Efficient Log-based Troubleshooting(ELT) system for cloud computing infrastructures. ELT adopts a novel hybrid log mining approach that combines coarse-grained and fine-grained log features to achieve both high accuracy and low overhead. Moreover, ELT can automatically extract key log messages and perform invariant checking to greatly simplify the troubleshooting task for the system administrator. We have implemented a prototype of the ELT system and conducted an extensive experimental study using real management console logs of a production cloud system and a Hadoop cluster. Our experimental results show that ELT can achieve more efficient and powerful troubleshooting support than existing schemes. More importantly, ELT can find software bugs that cannot be detected by current cloud system management practice. DA - 2011/// PY - 2011/// DO - 10.1109/srds.2011.11 SP - 11-20 SN - 2575-8462 ER - TY - CONF TI - Delay-capacity tradeoffs for mobile networks with levy walks and levy flights AU - Lee, K. AU - Kim, Y. AU - Chong, S. AU - Rhee, I. AU - Yi, Y. AB - This paper analytically derives the delay-capacity tradeoffs for Lévy mobility: Lévy walks and Lévy flights. Lévy mobility is a random walk with a power-law flight distribution. α is the power-law slope of the distribution and 0 <;; α ≤ 2. While in Lévy flight, each flight takes a constant flight time, in Lévy walk, it has a constant velocity which incurs strong spatio-temporal correlation as flight time depends on traveling distance. Lévy mobility is of special interest because it is known that Lévy mobility and human mobility share several common features including heavy-tail flight distributions. Humans highly influence the mobility of nodes (smartphones and cars) in real mobile networks as they carry or drive mobile nodes. Understanding the fundamental delay-capacity tradeoffs of Lévy mobility provides important insight into understanding the performance of real mobile networks. However, its power-law nature and strong spatio-temporal correlation make the scaling analysis non-trivial. This is in contrast to other random mobility models including Brownian motion, random waypoint and i.i.d. mobility which are amenable for a Markovian analysis. By exploiting the asymptotic characterization of the joint spatio-temporal probability density functions of Lévy models, the order of critical delay, the minimum delay required to achieve more throughput than Θ(1/√n) where n is the number of nodes in the network, is obtained. The results indicate that in Lévy walk, there is a phase transition that for 0 <; α <; 1, the critical delay is constantly Θ(n 1/2 ) and for 1 ≤ α ≤ 2, is Θ(n α/2 ). In contrast, Lévy flight has critical delay Θ(n α/2 ) for 0 <; α ≤ 2. C2 - 2011/// C3 - 2011 proceedings ieee infocom DA - 2011/// DO - 10.1109/infcom.2011.5935159 SP - 3128-3136 ER - TY - CONF TI - Contrabass: Concurrent transmissions without coordination for ad hoc networks AU - Yoon, S. AU - Rhee, I. AU - Jung, B. C. AU - Daneshrad, B. AU - Kim, J. H. AB - A practical protocol jointly considering PHY and MAC for MIMO based concurrent transmissions in wireless ad hoc networks, called Contrabass, is presented. Concurrent transmissions refer to simultaneous transmissions by multiple nodes over the same carrier frequency within the same interference range. Contrabass is the first-to-date open-loop based concurrent transmission protocol which implements simultaneous channel training for concurrently transmitting links without any control message exchange. Its MAC protocol is designed for each active transmitter to independently decide to transmit with near optimal transmission probability. Contrabass maximizes the number of successful concurrent transmissions, thus achieving very high aggregate throughput, low delays and scalability even under dynamic environments. The design choices of Contrabass are deliberately made to enable practical implementation which is demonstrated through GNURadio implementation and experimentation. C2 - 2011/// C3 - 2011 proceedings ieee infocom DA - 2011/// DO - 10.1109/infcom.2011.5934890 SP - 1134-1142 ER - TY - CONF TI - Communication genres: Integrating communication into the software engineering curriculum AU - Carter, M. AU - Vouk, M. AU - Gannod, G. C. AU - Burge, J. E. AU - Anderson, P. V. AU - Hoffman, M. E. AB - One way to improve the communication abilities of new software engineering graduates in the workplace is to integrate communication more effectively in the software engineering curriculum. But faculty typically conceive of communication as outside their realm of expertise. Based on the results of an NSF-funded project, we use theories of situated learning and genre to make the case that communication is integral to software engineering and that faculty are in the best position to guide students in becoming better communicators in the field. We identify software engineering genres and show how those genres may be used to integrate communication in the classroom and throughout the curriculum. C2 - 2011/// C3 - 2011 24th IEEE-CS Conference on Software Engineering Education and Training (CSEET) DA - 2011/// DO - 10.1109/cseet.2011.5876091 SP - 21-30 ER - TY - CONF TI - Assessing the accuracy of legal implementation readiness decisions AU - Massey, A. K. AU - Smith, B. AU - Otto, P. N. AU - Anton, A. I. AB - Software engineers regularly build systems that are required to comply with laws and regulations. To this end, software engineers must determine which requirements have met or exceeded their legal obligations and which requirements have not. Requirements that have met or exceeded their legal obligations are legally implementation ready, whereas requirements that have not met or exceeded their legal obligations need further refinement. Research is needed to better understand how to support software engineers in making these determinations. In this paper, we describe a case study in which we asked graduate-level software engineering students to assess whether a set of software requirements for an electronic health record system met or exceeded their corresponding legal obligations as expressed in regulations created pursuant to the U.S. Health Insurance Portability and Accountability Act (HIPAA). We compare the assessment made by graduate students with an assessment made by HIPAA compliance subject matter experts. Additionally, we contrast these results with those generated by a legal requirements triage algorithm. Our findings suggest that the average graduate-level software engineering student is ill-prepared to write legally compliant software with any confidence and that domain experts are an absolute necessity. Our findings also indicate the potential utility of legal requirements metrics in aiding software engineers as they make legal compliance decisions. C2 - 2011/// C3 - 2011 19th ieee international requirements engineering conference (re) DA - 2011/// DO - 10.1109/re.2011.6051661 SP - 207-216 ER - TY - CONF TI - A legal cross-references taxonomy for identifying conflicting software requirements AU - Maxwell, J. C. AU - Anton, A. I. AU - Swire, P. AB - Companies must ensure their software complies with relevant laws and regulations to avoid the risk of costly penalties, lost reputation, and brand damage resulting from noncompliance. Laws and regulations contain internal cross-references to portions of the same legal text, as well as cross-references to external legal texts. These cross-references introduce ambiguities, exceptions, as well as other challenges to regulatory compliance. Requirements engineers need guidance as to how to address cross-references in order to comply with the requirements of the law. Herein, we analyze each external cross-reference within the U.S. Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule to determine whether a cross-reference either: introduces a conflicting requirement, a conflicting definition, and/or refines an existing requirement. Herein, we propose a legal cross-reference taxonomy to aid requirements engineers in classifying cross-references as they specify . Analyzing cross-references enables us to address conflicting requirements that may otherwise thwart legal compliance. We identify five sets of conflicting compliance requirements and recommend strategies for resolving these conflicts. C2 - 2011/// C3 - 2011 19th ieee international requirements engineering conference (re) DA - 2011/// DO - 10.1109/re.2011.6051647 SP - 197-206 ER - TY - CONF TI - A invertible dimension reduction of curves on a manifold AU - Yi, S. AU - Krim, H. AU - Norris, L. K. AB - In this paper, we propose a novel lower dimensional representation of a shape sequence. The proposed dimension reduction is invertible and computationally more efficient in comparison to other related works. Theoretically, the differential geometry tools such as moving frame and parallel transportation are successfully adapted into the dimension reduction problem of high dimensional curves. Intuitively, instead of searching for a global flat subspace for curve embedding, we deployed a sequence of local flat subspaces adaptive to the geometry of both of the curve and the manifold it lies on. In practice, the experimental results of the dimension reduction and reconstruction algorithms well illustrate the advantages of the proposed theoretical innovation. C2 - 2011/// C3 - 2011 IEEE International Conference on Computer Vision Workshops (ICCV Workshops) DA - 2011/// DO - 10.1109/iccvw.2011.6130412 ER - TY - JOUR TI - Synthesizing Method Sequences for High-Coverage Testing AU - Thummalapenta, Suresh AU - Xie, Tao AU - Tillmann, Nikolai AU - Halleux, Jonathan AU - Su, Zhendong T2 - ACM SIGPLAN NOTICES AB - High-coverage testing is challenging. Modern object-oriented programs present additional challenges for testing. One key difficulty is the generation of proper method sequences to construct desired objects as method parameters. In this paper, we cast the problem as an instance of program synthesis that automatically generates candidate programs to satisfy a user-specified intent. In our setting, candidate programs are method sequences, and desired object states specify an intent. Automatic generation of desired method sequences is difficult due to its large search space---sequences often involve methods from multiple classes and require specific primitive values. This paper introduces a novel approach, called Seeker, to intelligently navigate the large search space. Seeker synergistically combines static and dynamic analyses: (1) dynamic analysis generates method sequences to cover branches; (2) static analysis uses dynamic analysis information for not-covered branches to generate candidate sequences; and (3) dynamic analysis explores and eliminates statically generated sequences. For evaluation, we have implemented Seeker and demonstrate its effectiveness on four subject applications totalling 28K LOC. We show that Seeker achieves higher branch coverage and def-use coverage than existing state-of-the-art approaches. We also show that Seeker detects 34 new defects missed by existing tools. DA - 2011/10// PY - 2011/10// DO - 10.1145/2076021.2048083 VL - 46 IS - 10 SP - 189-206 SN - 1558-1160 KW - Languages KW - Experimentation KW - Object-oriented testing KW - Symbolic execution ER - TY - CONF TI - Spatially diffuse pathsets for robust routing in ad hoc networks AU - Biswas, T. AU - Dutta, Rudra AB - Ad hoc wireless networks are characterized by frequent node mobility, limited power reserves and interfering transmissions. On-demand routing proves to be more successful in such networks, as it reduces the traffic overhead of sending periodic updates, but they may be susceptible to both random uncertainty in radio links, and malicious jamming. We consider a network of nodes addressed by their locations, and propose a novel routing technique that we call Petal Routing, which maximizes reliability by using pathsets, made of diverse multiple paths, in place of a single path. Petal Routing takes advantage of the broadcast nature of wireless networks to reduce the number of transmissions for multiple paths by overlapping the multiple diverse paths. Various tunable parameters built into the approach can be used to improve metrics such as delay, number of transmissions and packet delivery ratio. We evaluate the performance of our scheme using extensive simulations, and show that it is viable. C2 - 2011/// C3 - 2011 ieee global telecommunications conference (globecom 2011) DA - 2011/// DO - 10.1109/glocom.2011.6133499 ER - TY - CONF TI - On optimal tiered structures for network service bundles AU - Lv, Q. AU - Rouskas, G. N. AB - Network operators offer a variety of tiered services in which users may select only from a small set of tiers which offer progressively higher levels of service. Service bundling, whereby several services are combined together and sold as a single package, is also common in the telecommunications market. We consider the problem of determining optimal tiering structures for service bundles using tools from economics and utility theory. Our work provides insight into the selection and pricing of Internet tiered services. C2 - 2011/// C3 - 2011 ieee global telecommunications conference (globecom 2011) DA - 2011/// DO - 10.1109/glocom.2011.6133598 ER - TY - JOUR TI - Community-based anomaly detection in evolutionary networks AU - Che, Z. AU - Hendrix, W. AU - Samatova, N. T2 - The Journal of Intelligent Information Systems: Integrating Artificial Intelligence and Database Technologies AB - Networks of dynamic systems, including social networks, the World Wide Web, climate networks, and biological networks, can be highly clustered. Detecting clusters, or communities, in such dynamic networks is an emerging area of research; however, less work has been done in terms of detecting community-based anomalies. While there has been some previous work on detecting anomalies in graph-based data, none of these anomaly detection approaches have considered an important property of evolutionary networks—their community structure. In this work, we present an approach to uncover community-based anomalies in evolutionary networks characterized by overlapping communities. We develop a parameter-free and scalable algorithm using a proposed representative-based technique to detect all six possible types of community-based anomalies: grown, shrunken, merged, split, born, and vanished communities. We detail the underlying theory required to guarantee the correctness of the algorithm. We measure the performance of the community-based anomaly detection algorithm by comparison to a non–representative-based algorithm on synthetic networks, and our experiments on synthetic datasets show that our algorithm achieves a runtime speedup of 11–46 over the baseline algorithm. We have also applied our algorithm to two real-world evolutionary networks, Food Web and Enron Email. Significant and informative community-based anomaly dynamics have been detected in both cases. DA - 2011/// PY - 2011/// DO - 10.1007/s10844-011-0183-2 ER - TY - CONF TI - Benefits of multi wavelength approach to converter placement to support broadcast with available wavelengths AU - Babaoglu, A. C. AU - Dutta, Rudra AB - Optical networks are widely used in communication systems. Finding optimal converter placement for broadcast on optical networks has been an important area of research. In this problem, the free wavelengths on different links of a optical network are used to support network-wide broadcast, which is useful as a control channel or other OAM tasks. Previous work has articulated the essential difficulty of this problem. In this work, we recognize that bandwidth minimization is not an appropriate goal for this problem, and by using multiple wavelengths, and replicating some transmissions, it is possible to reduce the number of converters. We show example schemas to show that the difference in the optimal number of converters can be arbitrarily large, that adopting multiple wavelength paths whose union contains cycles can strictly reduce the optimal number, and then present a heuristic algorithm for broadcast path assignment to minimize converters under the new model. C2 - 2011/// C3 - 2011 ieee global telecommunications conference (globecom 2011) DA - 2011/// DO - 10.1109/glocom.2011.6134393 ER - TY - CONF TI - Aggregated-DAG Scheduling for Job Flow Maximization in Heterogeneous Cloud Computing AU - Saovapakhiran, B. AU - Michailidis, G. AU - Devetsikiotis, M. AB - Heterogeneous computing platforms such as Grid and Cloud computing are becoming prevalent and available online. As a result, resource management in these platforms is fundamentally critical to their global performance. Under the assumption of jobs comprised of subtasks forming DAG jobs, we focus on how to increase utilization and achieve near-optimal throughput performance on heterogeneous platforms. Our analysis and proposed algorithm are analytically derived and establish that, by aggregating multiple jobs using good scheduling, a near-optimal throughput can be achieved. Consequently, its limit is asymptotically converging to a certain value and can be written in the form of the service time of subtasks. Furthermore, our analysis shows how to explicitly compute the optimal throughput of computing systems, an important task for such a complex scheduling problem. In addition, we derive a simple super-job scheduling and show that its performance in term of throughput is better than the well-known Heterogeneous Earliest-Finish-Time (HEFT) algorithm. C2 - 2011/// C3 - 2011 ieee global telecommunications conference (globecom 2011) DA - 2011/// DO - 10.1109/glocom.2011.6133611 ER - TY - JOUR TI - Adaptive, transparent CPU scaling algorithms leveraging inter-node MPI communication regions AU - Lim, Min Yeol AU - Freeh, Vincent W. AU - Lowenthal, David K. T2 - PARALLEL COMPUTING AB - Although users of high-performance computing are most interested in raw performance, both energy and power consumption have become critical concerns. Because the CPU is often the major power consumer, some microprocessors allow frequency and voltage scaling, which enables a system to efficiently reduce CPU performance and power. When the CPU is not on the critical path, such dynamic frequency and voltage scaling can produce significant energy savings with little performance penalty. This paper presents an MPI runtime system that dynamically reduces CPU frequency and voltage during communication phases in MPI programs. It dynamically identifies such phases and, without a priori knowledge, selects the CPU frequency in order to minimize energy-delay product. All analysis and subsequent frequency and voltage scaling is within MPI and so is entirely transparent to the application. This means that the large number of existing MPI programs, as well as new ones being developed, can use our system without modification. Results show that the median reduction in energy-delay product for twelve benchmarks is 8%, the median energy reduction is 11%, and the median increase in execution time increase is only 2%. DA - 2011/// PY - 2011/// DO - 10.1016/j.parco.2011.07.001 VL - 37 IS - 10-11 SP - 667-683 SN - 1872-7336 KW - Power-aware computing KW - Message passing interface (MPI) ER - TY - CONF TI - Systematizing security test case planning using functional requirements phrases AU - Smith, B. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// SP - 1136-1137 ER - TY - CONF TI - Socio-technical developer networks: Should we trust our measurements? AU - Meneely, A. AU - Williams, L. AB - Software development teams must be properly structured to provide effectiv collaboration to produce quality software. Over the last several years, social network analysis (SNA) has emerged as a popular method for studying the collaboration and organization of people working in large software development teams. Researchers have been modeling networks of developers based on socio-technical connections found in software development artifacts. Using these developer networks, researchers have proposed several SNA metrics that can predict software quality factors and describe the team structure. But do SNA metrics measure what they purport to measure? The objective of this research is to investigate if SNA metrics represent socio-technical relationships by examining if developer networks can be corroborated with developer perceptions. To measure developer perceptions, we developed an online survey that is personalized to each developer of a development team based on that developer's SNA metrics. Developers answered questions about other members of the team, such as identifying their collaborators and the project experts. A total of 124 developers responded to our survey from three popular open source projects: the Linux kernel, the PHP programming language, and the Wireshark network protocol analyzer. Our results indicate that connections in the developer network are statistically associated with the collaborators whom the developers named. Our results substantiate that SNA metrics represent socio-technical relationships in open source development projects, while also clarifying how the developer network can be interpreted by researchers and practitioners. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// DO - 10.1145/1985793.1985832 SP - 281-290 ER - TY - CONF TI - Problem identification for structural test generation: First step towards cooperative developer testing AU - Xiao, X. S. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// SP - 1179-1181 ER - TY - JOUR TI - Predictable Task Migration for Locked Caches in Multi-Core Systems AU - Sarkar, Abhik AU - Mueller, Frank AU - Ramaprasad, Harini T2 - ACM SIGPLAN NOTICES AB - Locking cache lines in hard real-time systems is a common means of achieving predictability of cache access behavior and tightening as well as reducing worst case execution time, especially in a multitasking environment. However, cache locking poses a challenge for multi-core hard real-time systems since theoretically optimal scheduling techniques on multi-core architectures assume zero cost for task migration. Tasks with locked cache lines need to proactively migrate these lines before the next invocation of the task. Otherwise, cache locking on multi-core architectures becomes useless as predictability is compromised. This paper proposes hardware-based push-assisted cache migration as a means to retain locks on cache lines across migrations. We extend the push-assisted migration model with several cache migration techniques to efficiently retain locked cache lines on a bus-based chip multi-processor architecture. We also provide deterministic migration delay bounds that help the scheduler decide which migration technique(s) to utilize to relocate a single or multiple tasks. This information also allows the scheduler to determine feasibility of task migrations, which is critical for the safety of any hard real-time system. Such proactive migration of locked cache lines in multi-cores is unprecedented to our knowledge. DA - 2011/5// PY - 2011/5// DO - 10.1145/2016603.1967696 VL - 46 IS - 5 SP - 131-140 SN - 1558-1160 KW - Design KW - Experimentation KW - Real-Time Systems KW - Multi-Core Architectures KW - Timing Analysis KW - Task Migration ER - TY - CONF TI - Precise identification of problems for structural test generation AU - Xiao, X. S. AU - Xie, T. AU - Tillmann, N. AU - Halleux, J. AB - An important goal of software testing is to achieve at least high structural coverage. To reduce the manual efforts of producing such high-covering test inputs, testers or developers can employ tools built based on automated structural test-generation approaches. Although these tools can easily achieve high structural coverage for simple programs, when they are applied on complex programs in practice, these tools face various problems, such as (1) the external-method-call problem (EMCP), where tools cannot deal with method calls to external libraries; (2) the object-creation problem (OCP), where tools fails to generate method-call sequences to produce desirable object states. Since these tools currently could not be powerful enough to deal with these problems in testing complex programs in practice, we propose cooperative developer testing, where developers provide guidance to help tools achieve higher structural coverage. To reduce the efforts of developers in providing guidance to tools, in this paper, we propose a novel approach, called Covana, which precisely identifies and reports problems that prevent the tools from achieving high structural coverage primarily by determining whether branch statements containing notcovered branches have data dependencies on problem candidates. We provide two techniques to instantiate Covana to identify EMCPs and OCPs. Finally, we conduct evaluations on two open source projects to show the effectiveness of Covana in identifying EMCPs and OCPs. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// DO - 10.1145/1985793.1985876 SP - 611-620 ER - TY - CONF TI - DyTa: Dynamic symbolic execution guided with static verification results AU - Ge, X. AU - Taneja, K. AU - Xie, T. AU - Tillmann, N. AB - Software-defect detection is an increasingly important research topic in software engineering. To detect defects in a program, static verification and dynamic test generation are two important proposed techniques. However, both of these techniques face their respective issues. Static verification produces false positives, and on the other hand, dynamic test generation is often time consuming. To address the limitations of static verification and dynamic test generation, we present an automated defect-detection tool, called DyTa, that combines both static verification and dynamic test generation. DyTa consists of a static phase and a dynamic phase. The static phase detects potential defects with a static checker; the dynamic phase generates test inputs through dynamic symbolic execution to confirm these potential defects. DyTa reduces the number of false positives compared to static verification and performs more efficiently compared to dynamic test generation. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// DO - 10.1145/1985793.1985971 SP - 992-994 ER - TY - CONF TI - Covana: Precise identification of problems in Pex AU - Xiao, X. S. AU - Xie, T. AU - Tillmann, N. AU - Halleux, J. AB - Achieving high structural coverage is an important goal of software testing. Instead of manually producing test inputs that achieve high structural coverage, testers or developers can employ tools built based on automated test-generation approaches, such as Pex, to automatically generate such test inputs. Although these tools can easily generate test inputs that achieve high structural coverage for simple programs, when applied on complex programs in practice, these tools face various problems, such as the problems of dealing with method calls to external libraries or generating method-call sequences to produce desired object states. Since these tools are currently not powerful enough to deal with these various problems in testing complex programs, we propose cooperative developer testing, where developers provide guidance to help tools achieve higher structural coverage. In this demo, we present Covana, a tool that precisely identifies and reports problems that prevent Pex from achieving high structural coverage. Covana identifies problems primarily by determining whether branch statements containing not-covered branches have data dependencies on problem candidates. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// DO - 10.1145/1985793.1985976 SP - 1004-1006 ER - TY - JOUR TI - Bandwidth allocation under end-to-end percentile delay bounds AU - Anjum, Bushra AU - Perros, Harry AU - Mountrouidou, Xenia AU - Kontovasilis, Kimon T2 - INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT AB - SUMMARY We describe an efficient and accurate approximation method for calculating the bandwidth that should be allocated on each link along the path of a point‐to‐point Multiprotocol Label Switching connection, so that the end‐to‐end delay D is less than or equal to a given value T with a probability γ , that is, P ( D ≤ T ) = γ . We model a connection by a tandem queuing network of infinite capacity queues. The arrival process of packets to the connection is assumed to be bursty and correlated and it is depicted by a two‐stage Markov‐Modulated Poisson Process. The service times are exponentially distributed. The proposed method uses only the first queue of the tandem queuing network to construct an upper and lower bound of the required bandwidth so that P ( D ≤ T ) = γ . Subsequently, we estimate the required bandwidth using a simple interpolation function between the two bounds. Extensive comparisons with simulation showed that the results obtained have an average relative error of 1.25%. Copyright © 2011 John Wiley & Sons, Ltd. DA - 2011/// PY - 2011/// DO - 10.1002/nem.783 VL - 21 IS - 6 SP - 536-547 SN - 1099-1190 ER - TY - CONF TI - A case study on refactoring in Haskell programs AU - Lee, D. Y. C2 - 2011/// C3 - 2011 33rd International Conference on Software Engineering (ICSE) DA - 2011/// SP - 1164-1166 ER - TY - JOUR TI - Vehicle Tracking Through the Exploitation of Remote Sensing and LWIR Polarization Science AU - Clouse, Hamilton Scott AU - Krim, Hamid AU - Sakla, Wesam AU - Mendoza-Schrock, Olga T2 - POLARIZATION SCIENCE AND REMOTE SENSING V AB - Vehicle tracking is an integral component in layered sensing exploitation applications. The utilization of a combination of sensing modalities and processing techniques provides better insight about a situation than can be achieved with a single sensing modality. In this work, several robust features are explored for vehicle tracking using data captured in a remote sensing setting. A target area is surveyed by a sensor operating capturing polarization information in the longwave infrared (LWIR) band. We here extend our previous work ([1]) to experimental analysis of several feature sets including three classic features (Stokes images, DoLP, the Degree of Linear Polarization, and AoP, the Angle of Polarization) and several geometry inspired features.1 DA - 2011/// PY - 2011/// DO - 10.1117/12.901556 VL - 8160 SP - SN - 1996-756X KW - layered sensing KW - distributed sensing KW - polarimetric KW - infrared KW - tracking KW - feature-aided KW - fusion KW - multisensor ER - TY - JOUR TI - Maximum likelihood autocalibration AU - Heinrich, Stuart B. AU - Snyder, Wesley E. AU - Frahm, Jan-Michael T2 - IMAGE AND VISION COMPUTING AB - This paper addresses the problem of autocalibration, which is a critical step in existing uncalibrated structure from motion algorithms that utilize an initialization to avoid the local minima in metric bundle adjustment. Currently, all known direct (not non-linear) solutions to the uncalibrated structure from motion problem solve for a projective reconstruction that is related to metric by some unknown homography, and hence a necessary step in obtaining a metric reconstruction is the subsequent estimation of the rectifying homography, known as autocalibration. Although autocalibration is a well-studied problem, previous approaches have relied upon heuristic objective functions, and have a reputation for instability. We propose a maximum likelihood objective and show that it can be implemented robustly and efficiently and often provides substantially greater accuracy, especially when there are fewer views or greater noise. DA - 2011/9// PY - 2011/9// DO - 10.1016/j.imavis.2011.07.003 VL - 29 IS - 10 SP - 653-665 SN - 1872-8138 KW - Autocalibration KW - Self-calibration KW - Maximum likelihood KW - Absolute dual quadric KW - Structure from motion ER - TY - JOUR TI - Designing Fast and Scalable XACML Policy Evaluation Engines AU - Liu, Alex X. AU - Chen, Fei AU - Hwang, JeeHyun AU - Xie, Tao T2 - IEEE TRANSACTIONS ON COMPUTERS AB - Most prior research on policies has focused on correctness. While correctness is an important issue, the adoption of policy-based computing may be limited if the resulting systems are not implemented efficiently and thus perform poorly. To increase the effectiveness and adoption of policy-based computing, in this paper, we propose fast policy evaluation algorithms that can be adapted to support various policy languages. In this paper, we focus on XACML policy evaluation because XACML has become the de facto standard for specifying access control policies, has been widely used on web servers, and is most complex among existing policy languages. We implemented our algorithms in a policy evaluation system called XEngine and conducted side-by-side comparison with Sun Policy Decision Point (PDP), the industrial standard for XACML policy evaluation. The results show that XEngine is orders of magnitude faster than Sun PDP. The performance difference grows almost linearly with the number of rules in an XACML policy. To our best knowledge, there is no prior work on improving XACML policy evaluation performance. This paper represents the first step in exploring this unknown space. DA - 2011/12// PY - 2011/12// DO - 10.1109/tc.2010.274 VL - 60 IS - 12 SP - 1802-1817 SN - 1557-9956 KW - Web servers KW - XACML KW - policy evaluation KW - policy-based computing KW - access control KW - policy decision point ER - TY - JOUR TI - DENSE: efficient and prior knowledge-driven discovery of phenotype-associated protein functional modules AU - Hendrix, Willam AU - Rocha, Andrea M. AU - Padmanabhan, Kanchana AU - Choudhary, Alok AU - Scott, Kathleen AU - Mihelcic, James R. AU - Samatova, Nagiza F. T2 - BMC SYSTEMS BIOLOGY AB - Identifying cellular subsystems that are involved in the expression of a target phenotype has been a very active research area for the past several years. In this paper, cellular subsystem refers to a group of genes (or proteins) that interact and carry out a common function in the cell. Most studies identify genes associated with a phenotype on the basis of some statistical bias, others have extended these statistical methods to analyze functional modules and biological pathways for phenotype-relatedness. However, a biologist might often have a specific question in mind while performing such analysis and most of the resulting subsystems obtained by the existing methods might be largely irrelevant to the question in hand. Arguably, it would be valuable to incorporate biologist's knowledge about the phenotype into the algorithm. This way, it is anticipated that the resulting subsytems would not only be related to the target phenotype but also contain information that the biologist is likely to be interested in.In this paper we introduce a fast and theoretically guranteed method called DENSE (Dense and ENriched Subgraph Enumeration) that can take in as input a biologist's prior knowledge as a set of query proteins and identify all the dense functional modules in a biological network that contain some part of the query vertices. The density (in terms of the number of network egdes) and the enrichment (the number of query proteins in the resulting functional module) can be manipulated via two parameters γ and μ, respectively.This algorithm has been applied to the protein functional association network of Clostridium acetobutylicum ATCC 824, a hydrogen producing, acid-tolerant organism. The algorithm was able to verify relationships known to exist in literature and also some previously unknown relationships including those with regulatory and signaling functions. Additionally, we were also able to hypothesize that some uncharacterized proteins are likely associated with the target phenotype. The DENSE code can be downloaded from http://www.freescience.org/cs/DENSE/ DA - 2011/10/24/ PY - 2011/10/24/ DO - 10.1186/1752-0509-5-172 VL - 5 SP - SN - 1752-0509 ER - TY - JOUR TI - Contextual Decision Making in General Game Playing AU - Sheng, Xinxin AU - Thuente, David T2 - 2011 23RD IEEE INTERNATIONAL CONFERENCE ON TOOLS WITH ARTIFICIAL INTELLIGENCE (ICTAI 2011) AB - General Game Playing refers to designing Artificial Intelligence agents that are capable of playing different games without human intervention. The games are defined by sets of rules represented in logic descriptions and the agent players interact in a multi-agent system with a game server coordinating the legality of the operations and keeping the players informed of the state changes. This paper describes a general game agent that isolates the heuristic search coverage for contextual decision making by efficiently creating dynamic decision trees. The influence of certain game features is evaluated within the current decision context rather than on the whole game scale. The benefit of this approach is shown by performance comparison with agents that do search, learning, and learning with decision trees. We show this for a variety of games and have compared favorably against well known general game players and replicated actions of known human expert strategies. DA - 2011/// PY - 2011/// DO - 10.1109/ictai.2011.108 SP - 679-684 SN - 1082-3409 KW - General Game Playing KW - decision tree KW - machine learning KW - decision making ER - TY - JOUR TI - Selecting and using views to compute aggregate queries AU - Afrati, F. AU - Chirkova, R. T2 - Journal of Computer and System Sciences AB - We consider a workload of aggregate queries and investigate the problem of selecting materialized views that (1) provide equivalent rewritings for all the queries, and (2) are optimal, in that the cost of evaluating the query workload is minimized. We consider conjunctive views and rewritings, with or without aggregation; in each rewriting, only one view contributes to computing the aggregated query output. We look at query rewriting using existing views and at view selection. In the query-rewriting problem, we give sufficient and necessary conditions for a rewriting to exist. For view selection, we prove complexity results. Finally, we give algorithms for obtaining rewritings and selecting views. DA - 2011/// PY - 2011/// DO - 10.1016/j.jcss.2010.10.003 VL - 77 IS - 6 SP - 1079-1107 ER - TY - JOUR TI - ScalaExtrap: Trace-Based Communication Extrapolation for SPMD Programs AU - Wu, Xing AU - Mueller, Frank T2 - ACM SIGPLAN NOTICES AB - Performance modeling for scientific applications is important for assessing potential application performance and systems procurement in high-performance computing (HPC). Recent progress on communication tracing opens up novel opportunities for communication modeling due to its lossless yet scalable trace collection. Estimating the impact of scaling on communication efficiency still remains non-trivial due to execution-time variations and exposure to hardware and software artifacts. This work contributes a fundamentally novel modeling scheme. We synthetically generate the application trace for large numbers of nodes by extrapolation from a set of smaller traces. We devise an innovative approach for topology extrapolation of single program, multiple data (SPMD) codes with stencil or mesh communication. The extrapolated trace can subsequently be (a) replayed to assess communication requirements before porting an application, (b) transformed to auto-generate communication benchmarks for various target platforms, and (c) analyzed to detect communication inefficiencies and scalability limitations. To the best of our knowledge, rapidly obtaining the communication behavior of parallel applications at arbitrary scale with the availability of timed replay, yet without actual execution of the application at this scale is without precedence and has the potential to enable otherwise infeasible system simulation at the exascale level. DA - 2011/8// PY - 2011/8// DO - 10.1145/2038037.1941569 VL - 46 IS - 8 SP - 113-122 SN - 1558-1160 KW - High-Performance Computing KW - Message Passing KW - Tracing KW - Performance Prediction KW - Measurement KW - Performance ER - TY - JOUR TI - A Survey of Network Design Problems and Joint Design Approaches in Wireless Mesh Networks AU - Pathak, Parth H. AU - Dutta, Rudra T2 - IEEE COMMUNICATIONS SURVEYS AND TUTORIALS AB - Over the last decade, the paradigm of Wireless Mesh Networks (WMNs) has matured to a reasonably commonly understood one, and there has been extensive research on various areas related to WMNs such as design, deployment, protocols, performance, etc. The quantity of research being conducted in the area of wireless mesh design has dramatically increased in the past few years, due to increasing interest in this paradigm as its potential for the "last few miles", and the possibility of significant wireless services in metropolitan area networks. This recent work has focused increasingly on joint design problems, together with studies in designing specific aspects of the WMN such as routing, power control etc. in isolation. While excellent surveys and tutorials pertaining to WMNs exist in literature, the explosive growth of research in the area of specific design issues, and especially joint design, has left them behind. Our objective in this paper is to identify the fundamental WMN design problems of interference modeling, power control, topology control, link scheduling, and routing, and provide brief overviews, together with a survey of the recent research on these topics, with special stress on joint design methods. We believe this paper will fulfill an outstanding need in informing the interested student and researcher in getting familiar with this abundant recent research area, and starting research. DA - 2011/// PY - 2011/// DO - 10.1109/surv.2011.060710.00062 VL - 13 IS - 3 SP - 396-428 SN - 1553-877X KW - Wireless Mesh Networks KW - Interference Modeling and Mitigation KW - Power Control KW - Topology Control KW - Routing KW - Channel Assignment KW - Scheduling KW - Joint Design Approaches KW - Cross-layer Design KW - Network Capacity and Planning ER - TY - JOUR TI - Retrofitting unit tests for parameterized unit testing AU - Thummalapenta, S. AU - Marri, M. R. AU - Xie, T. AU - Tillmann, N. AU - Halleux, J. T2 - Fundamental approaches to software engineering DA - 2011/// PY - 2011/// VL - 6603 SP - 294-309 ER - TY - JOUR TI - Fast Exact ILP Decompositions for Ring RWA AU - Yetginer, Emre AU - Liu, Zeyu AU - Rouskas, George N. T2 - JOURNAL OF OPTICAL COMMUNICATIONS AND NETWORKING AB - Wavelength division multiplexing rings are now capable of supporting more than 100 wavelengths over a single fiber. Conventional link and path formulations for the routing and wavelength assignment problem are inefficient due to the inherent symmetry in wavelength assignment and the fact that the problem size increases fast with the number of wavelengths. Although a formulation based on maximal independent sets (MIS) does not have these drawbacks, it suffers from exponential growth in the number of variables with increasing network size. We develop a new ILP (integer linear program) formulation based on the key idea of partitioning the path set and representing the MIS in the original network using the independent sets calculated in each of these partitions. This exact decomposition trades off the number of variables with the number of constraints and, as a result, achieves a much better scalability in terms of network dimension. Numerical results on ring networks of various sizes demonstrate that this new ILP decomposition achieves a decrease of several orders of magnitude in running time compared to existing formulations. Our main contribution is a novel and extremely fast technique for obtaining, in a few seconds using commodity CPUs, optimal solutions to instances of maximum size SONET rings with any number of wavelengths; such instances cannot be tackled with classical formulations without vast investments in computational resources and time. DA - 2011/7// PY - 2011/7// DO - 10.1364/jocn.3.000577 VL - 3 IS - 7 SP - 577-586 SN - 1943-0639 KW - Integer linear programming (ILP) KW - Ring networks KW - Routing and wavelength assignment (RWA) ER - TY - JOUR TI - MODEL CHECKING FOR VERIFICATION OF MANDATORY ACCESS CONTROL MODELS AND PROPERTIES AU - Hu, Vincent C. AU - Kuhn, D. Richard AU - Xie, Tao AU - Hwang, Jeehyun T2 - INTERNATIONAL JOURNAL OF SOFTWARE ENGINEERING AND KNOWLEDGE ENGINEERING AB - Mandatory access control (MAC) mechanisms control which users or processes have access to which resources in a system. MAC policies are increasingly specified to facilitate managing and maintaining access control. However, the correct specification of the policies is a very challenging problem. To formally and precisely capture the security properties that MAC should adhere to, MAC models are usually written to bridge the rather wide gap in abstraction between policies and mechanisms. In this paper, we propose a general approach for property verification for MAC models. The approach defines a standardized structure for MAC models, providing for both property verification and automated generation of test cases. The approach expresses MAC models in the specification language of a model checker and expresses generic access control properties in the property language. Then the approach uses the model checker to verify the integrity, coverage, and confinement of these properties for the MAC models and finally generates test cases via combinatorial covering array for the system implementations of the models. DA - 2011/2// PY - 2011/2// DO - 10.1142/s021819401100513x VL - 21 IS - 1 SP - 103-127 SN - 1793-6403 KW - Access control KW - policy KW - model KW - testing ER - TY - JOUR TI - Intertemporal Discount Factors as a Measure of Trustworthiness in Electronic Commerce AU - Hazard, Christopher J. AU - Singh, Munindar P. T2 - IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING AB - In multiagent interactions, such as e-commerce and file sharing, being able to accurately assess the trustworthiness of others is important for agents to protect themselves from losing utility. Focusing on rational agents in e-commerce, we prove that an agent's discount factor (time preference of utility) is a direct measure of the agent's trustworthiness for a set of reasonably general assumptions and definitions. We propose a general list of desiderata for trust systems and discuss how discount factors as trustworthiness meet these desiderata. We discuss how discount factors are a robust measure when entering commitments that exhibit moral hazards. Using an online market as a motivating example, we derive some analytical methods both for measuring discount factors and for aggregating the measurements. DA - 2011/5// PY - 2011/5// DO - 10.1109/tkde.2010.141 VL - 23 IS - 5 SP - 699-712 SN - 1558-2191 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79953171081&partnerID=MN8TOARS KW - Trust KW - reputation KW - intertemporal discounting ER - TY - JOUR TI - False Data Injection Attacks against State Estimation in Electric Power Grids AU - Liu, Yao AU - Ning, Peng AU - Reiter, Michael K. T2 - ACM TRANSACTIONS ON INFORMATION AND SYSTEM SECURITY AB - A power grid is a complex system connecting electric power generators to consumers through power transmission and distribution networks across a large geographical area. System monitoring is necessary to ensure the reliable operation of power grids, and state estimation is used in system monitoring to best estimate the power grid state through analysis of meter measurements and power system models. Various techniques have been developed to detect and identify bad measurements, including interacting bad measurements introduced by arbitrary, nonrandom causes. At first glance, it seems that these techniques can also defeat malicious measurements injected by attackers. In this article, we expose an unknown vulnerability of existing bad measurement detection algorithms by presenting and analyzing a new class of attacks, called false data injection attacks , against state estimation in electric power grids. Under the assumption that the attacker can access the current power system configuration information and manipulate the measurements of meters at physically protected locations such as substations, such attacks can introduce arbitrary errors into certain state variables without being detected by existing algorithms. Moreover, we look at two scenarios, where the attacker is either constrained to specific meters or limited in the resources required to compromise meters. We show that the attacker can systematically and efficiently construct attack vectors in both scenarios to change the results of state estimation in arbitrary ways. We also extend these attacks to generalized false data injection attacks , which can further increase the impact by exploiting measurement errors typically tolerated in state estimation. We demonstrate the success of these attacks through simulation using IEEE test systems, and also discuss the practicality of these attacks and the real-world constraints that limit their effectiveness. DA - 2011/5// PY - 2011/5// DO - 10.1145/1952982.1952995 VL - 14 IS - 1 SP - SN - 1557-7406 KW - Algorithms KW - Security KW - Power grids KW - state estimation KW - attack ER - TY - JOUR TI - Common Intervals of Multiple Permutations AU - Heber, Steffen AU - Mayr, Richard AU - Stoye, Jens T2 - ALGORITHMICA DA - 2011/6// PY - 2011/6// DO - 10.1007/s00453-009-9332-1 VL - 60 IS - 2 SP - 175-206 SN - 1432-0541 KW - Common intervals of permutations KW - Multichromosomal permutations KW - Circular permutations ER - TY - JOUR TI - Adding Percentiles of Erlangian Distributions AU - Anjum, Bushra AU - Perros, Harry T2 - IEEE COMMUNICATIONS LETTERS AB - In networking, enterprise computing and many other areas the issue of adding percentiles of a performance metric, such as the response time, arises regularly. Percentiles cannot be added using the arithmetic sum, and surprisingly there are no known formulae that permit us to do so correctly. In this paper, we obtain an exact analytical expression for adding percentiles of random variables which can be represented by a series of generalized exponential stages (e.g., Erlang, hypoexponential and two-stage Coxian). We demonstrate the applicability of our results by an example in which we use our expressions in the Dijkstra's algorithm to calculate the shortest 'percentile delay' path. DA - 2011/3// PY - 2011/3// DO - 10.1109/lcomm.2011.011011.102143 VL - 15 IS - 3 SP - 346-348 SN - 1089-7798 KW - Adding percentiles KW - Erlang KW - two-stage Coxian KW - quality of service KW - hypoexponential KW - shortest path calculation ER - TY - JOUR TI - A systematic literature review of actionable alert identification techniques for automated static code analysis AU - Heckman, Sarah AU - Williams, Laurie T2 - INFORMATION AND SOFTWARE TECHNOLOGY AB - Automated static analysis (ASA) identifies potential source code anomalies early in the software development lifecycle that could lead to field failures. Excessive alert generation and a large proportion of unimportant or incorrect alerts (unactionable alerts) may cause developers to reject the use of ASA. Techniques that identify anomalies important enough for developers to fix (actionable alerts) may increase the usefulness of ASA in practice. The goal of this work is to synthesize available research results to inform evidence-based selection of actionable alert identification techniques (AAIT). Relevant studies about AAITs were gathered via a systematic literature review. We selected 21 peer-reviewed studies of AAITs. The techniques use alert type selection; contextual information; data fusion; graph theory; machine learning; mathematical and statistical models; or dynamic detection to classify and prioritize actionable alerts. All of the AAITs are evaluated via an example with a variety of evaluation metrics. The selected studies support (with varying strength), the premise that the effective use of ASA is improved by supplementing ASA with an AAIT. Seven of the 21 selected studies reported the precision of the proposed AAITs. The two studies with the highest precision built models using the subject program’s history. Precision measures how well a technique identifies true actionable alerts out of all predicted actionable alerts. Precision does not measure the number of actionable alerts missed by an AAIT or how well an AAIT identifies unactionable alerts. Inconsistent use of evaluation metrics, subject programs, and ASAs in the selected studies preclude meta-analysis and prevent the current results from informing evidence-based selection of an AAIT. We propose building on an actionable alert identification benchmark for comparison and evaluation of AAIT from literature on a standard set of subjects and utilizing a common set of evaluation metrics. DA - 2011/4// PY - 2011/4// DO - 10.1016/j.infsof.2010.12.007 VL - 53 IS - 4 SP - 363-387 SN - 1873-6025 KW - Automated static analysis KW - Systematic literature review KW - Actionable alert identification KW - Unactionable alert mitigation KW - Warning prioritization KW - Actionable alert prediction ER - TY - JOUR TI - A Dynamic Recursive Unified Internet Design (DRUID) AU - Touch, Joe AU - Baldine, Ilia AU - Dutta, Rudra AU - Finn, Gregory G. AU - Ford, Bryan AU - Jordan, Scott AU - Massey, Dan AU - Matta, Abraham AU - Papadopoulos, Christos AU - Reiher, Peter AU - Rouskas, George T2 - COMPUTER NETWORKS AB - The Dynamic Recursive Unified Internet Design (DRUID) is a future Internet design that unifies overlay networks with conventional layered network architectures. DRUID is based on the fundamental concept of recursion, enabling a simple and direct network architecture that unifies the data, control, management, and security aspects of the current Internet, leading to a more trustworthy network. DRUID’s architecture is based on a single recursive block that can adapt to support a variety of communication functions, including parameterized mechanisms for hard/soft state, flow and congestion control, sequence control, fragmentation and reassembly, compression, encryption, and error recovery. This recursion is guided by the structure of a graph of translation tables that help compartmentalize the scope of various functions and identifier spaces, while relating these spaces for resource discovery, resolution, and routing. The graph also organizes persistent state that coordinates behavior between individual data events (e.g., coordinating packets as a connection), among different associations (e.g., between connections), as well as helping optimize the recursive discovery process through caching, and supporting prefetching and distributed pre-coordination. This paper describes the DRUID architecture composed of these three parts (recursive block, translation tables, persistent state), and highlights its goals and benefits, including unifying the data, control, management, and security planes currently considered orthogonal aspects of network architecture. DA - 2011/3/10/ PY - 2011/3/10/ DO - 10.1016/j.comnet.2010.12.016 VL - 55 IS - 4 SP - 919-935 SN - 1872-7069 KW - Network architecture KW - Future internet KW - Recursive networks KW - Dynamic stacks ER - TY - JOUR TI - Truckers drive their own assessment for obstructive sleep apnea: A collaborative approach to online self-assessment for obstructive sleep apnea AU - Smith, B. AU - Phillips, B. A. T2 - Journal of Clinical Sleep Medicine DA - 2011/// PY - 2011/// VL - 7 IS - 3 SP - 238-242 ER - TY - JOUR TI - Taming the elephants: New TCP slow start AU - Ha, Sangtae AU - Rhee, Injong T2 - COMPUTER NETWORKS AB - Standard slow start does not work well under large bandwidth-delay product (BDP) networks. We find two reasons for this problem in three popular existing operating systems: Linux, FreeBSD and Windows XP. The first reason is that heavy packet losses occur because of the exponential increase of the congestion window during standard slow start. Recovering from heavy packet losses puts extremely high loads on end systems, rendering the end systems completely unresponsive for a long period of time, and results in a long blackout period without transmission. This problem commonly occurs with all three operating systems. The second reason is that some proprietary protocol optimizations applied to slow start happen to slow down the loss recovery followed by slow start. Although improving the system bottleneck by optimizing data structures is valuable especially for addressing the processing overload with heavy packet losses, it is not effective for the prolonged loss recovery caused by proprietary optimizations. In addition, a large number of packet losses are not desirable since they waste network bandwidth and lead TCP into frequent timeouts and loss synchronization which results in under-utilization of the network. We propose a new slow start algorithm, called Hybrid Start (HyStart), that finds a “safe” exit point for slow start at which it can terminate and safely advance to the congestion avoidance phase without causing heavy packet loss. HyStart uses ACK trains and RTT delay samples to detect whether (1) the forward path is congested or (2) the current size of the congestion window has reached the available capacity of the forward path. HyStart is a plugin to TCP senders and requires no change on TCP receivers. We implement HyStart for TCP-NewReno and TCP-SACK in Linux and compare its performance with five different slow start schemes on the TCP receivers of the three different operating systems on the Internet and also in lab testbeds. Our results indicate that HyStart works consistently well under diverse network environments, including asymmetric links, wireless networks, and high and low BDP networks. Especially with different operating system receivers (Windows XP and FreeBSD), HyStart improves the start-up throughput of TCP significantly by more than 2 to 3 times and is the default slow start algorithm of CUBIC since Linux 2.6.29. DA - 2011/6/23/ PY - 2011/6/23/ DO - 10.1016/j.comnet.2011.01.014 VL - 55 IS - 9 SP - 2092-2110 SN - 1872-7069 KW - Slow start KW - Congestion control KW - Linux slow start KW - SACK processing KW - High-speed TCP protocols ER - TY - JOUR TI - Anomalous Loss Performance for Mixed Real-Time and TCP Traffic in Routers With Very Small Buffers AU - Vishwanath, Arun AU - Sivaraman, Vijay AU - Rouskas, George N. T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - In the past few years there has been vigorous debate regarding the size of buffers required at core Internet routers. Recent arguments supported by theory and experimentation show that under certain conditions, core router buffer sizes of a few tens of packets suffice for realizing acceptable end-to-end TCP throughputs. This is a significant step toward the realization of optical packet switched (OPS) networks, which are inherently limited in their ability to buffer optical signals. However, prior studies have largely ignored the presence of real-time traffic, which is increasing in importance as a source of revenue for Internet service providers. In this paper, we study the interaction that happens between real-time (open-loop) and TCP (closed-loop) traffic when they multiplex at buffers of very small size (few tens of packets) and make a significant discovery - namely that in a specific range of buffer size, real-time traffic losses increase as buffer size becomes larger. Our contributions pertaining to this anomalous behavior are threefold. First, we exhibit this anomalous loss performance for real-time traffic via extensive simulations using synthetic traffic and real video traces. Second, we develop quantitative models that reveal the dynamics of buffer sharing between real-time and TCP traffic that lead to this behavior. Third, we show how various factors such as the nature of real-time traffic, mixture of long-lived and short-lived TCP flows, and packet sizes impact the severity of the anomaly. Our study is the first to consider interactions between real-time and TCP traffic in very small (potentially all-optical) buffers and informs router manufacturers and network operators of the factors to consider when dimensioning such small buffer sizes for desired performance balance between real-time and TCP traffic. DA - 2011/8// PY - 2011/8// DO - 10.1109/tnet.2010.2091721 VL - 19 IS - 4 SP - 933-946 SN - 1558-2566 KW - Anomalous loss performance KW - mixed TCP and real-time traffic KW - optical packet switched (OPS) networks KW - routers with very small buffers ER - TY - JOUR TI - A study of performance and scalability metrics of a SIP proxy server - a practical approach AU - Subramanian, Sureshkumar V. AU - Dutta, Rudra T2 - JOURNAL OF COMPUTER AND SYSTEM SCIENCES AB - In recent years, Internet Protocol (IP) telephony has been a real alternative to the traditional Public Switched Telephone Networks (PSTN). IP telephony offers more flexibility in the implementation of new features and services. The Session Initiation Protocol (SIP) is becoming a popular signalling protocol for Voice over IP (VoIP) based applications. The SIP proxy server is a software application that provides call routing services by parsing and forwarding all the incoming SIP packets in an IP telephony network. The efficiency of this process can create large scale, highly reliable packet voice networks for service providers and enterprises. We established that the efficient design and implementation of the SIP proxy server architecture can enhance the performance characteristics of a SIP proxy server significantly. Since SIP proxy server performance can be characterised by its transaction states of each SIP session, we emulated the M/M/1 performance model of the SIP proxy server and studied some of the key performance benchmarks such as average response time to process the SIP calls, and mean number of SIP calls in the system. We showed its limitations, and then studied an alternative M/M/c based SIP proxy server performance model with enhanced performance model and studied additional key performance characteristics such as server utilisation, queue size and memory utilisation. Provided the comparative results between the predicted results with the experimental results conducted in a lab environment. DA - 2011/9// PY - 2011/9// DO - 10.1016/j.jcss.2010.08.006 VL - 77 IS - 5 SP - 884-897 SN - 0022-0000 KW - SIP KW - Performance KW - M/M/c KW - M/M/1 ER - TY - JOUR TI - A Scaled, Performance Driven Evaluation of the Layered Sensing Framework Utilizing Polarimetric Infrared Imagery AU - Clouse, Hamilton Scott AU - Krim, Hamid AU - Mendoza-Schrock, Olga T2 - EVOLUTIONARY AND BIO-INSPIRED COMPUTATION: THEORY AND APPLICATIONS V AB - The layered sensing framework, in application, provides a useful, but complex integration of information sources, e.g. multiple sensing modalities and operating conditions. It is the implied trade-off between sensor fidelity and system complexity that we address here. Abstractly, each sensor/source of information in a layered sensing application can be viewed as a node in the network of constituent sensors. Regardless of the sensing modality, location, scope, etc., each sensor collects information locally to be utilized by the system as a whole for further exploitation. Consequently, the information may be distributed throughout the network and not necessarily coalesced in a central node/location. We present, initially, an analysis of polarimetric infrared data, with two novel features, as one of the input modalities to such a system. We then proceed with statistical and geometric analyses of an example network, thus quantifying the advantages and drawbacks of a specific application of the layered sensing framework. DA - 2011/// PY - 2011/// DO - 10.1117/12.886510 VL - 8059 SP - SN - 1996-756X KW - layered sensing KW - distributed sensing KW - polarimetric KW - infrared KW - tracking KW - feature-aided KW - fusion KW - multisensor ER - TY - JOUR TI - Visualizing combinatorial auctions AU - Hsiao, Joe Ping-Lin AU - Healey, Christopher G. T2 - VISUAL COMPUTER DA - 2011/6// PY - 2011/6// DO - 10.1007/s00371-011-0576-9 VL - 27 IS - 6-8 SP - 633-643 SN - 1432-2315 KW - Combinatorial auction KW - Ecommerce KW - Perception KW - Visualization ER - TY - JOUR TI - The local geometry of multiattribute tradeoff preferences AU - McGeachie, Michael AU - Doyle, Jon T2 - ARTIFICIAL INTELLIGENCE AB - Existing representations for multiattribute ceteris paribus preference statements have provided useful treatments and clear semantics for qualitative comparisons, but have not provided similarly clear representations or semantics for comparisons involving quantitative tradeoffs. We use directional derivatives and other concepts from elementary differential geometry to interpret conditional multiattribute ceteris paribus preference comparisons that state bounds on quantitative tradeoff ratios. This semantics extends the familiar economic notion of marginal rate of substitution to multiple continuous or discrete attributes. The same geometric concepts also provide means for interpreting statements about the relative importance of different attributes. DA - 2011/5// PY - 2011/5// DO - 10.1016/j.artint.2010.11.014 VL - 175 IS - 7-8 SP - 1122-1152 SN - 1872-7921 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79954686976&partnerID=MN8TOARS KW - Decision theory KW - Preference representation KW - Multiattribute tradeoffs KW - Ceteris paribus reasoning ER - TY - JOUR TI - Spin-Peierls transition in the S=1/2 compound TiPO4 featuring large intrachain coupling AU - Law, J. M. AU - Hoch, C. AU - Glaum, R. AU - Heinmaa, I. AU - Stern, R. AU - Kang, J. AU - Lee, C. AU - Whangbo, M. -H. AU - Kremer, R. K. T2 - PHYSICAL REVIEW B AB - We investigated the magnetic and structural properties of the quasi-one-dimensional 3${d}^{1}$ quantum chain system TiPO${}_{4}$ ($J~$ 965 K) by magnetic susceptibility, heat capacity, electron spin resonance, x-ray diffraction, and nuclear magnetic resonance (NMR) measurements, and by density functional theory (DFT) calculations. TiPO${}_{4}$ undergoes two magnetostructural phase transitions, one at 111 K and the other at 74 K. Below 74 K, NMR detects two different $^{31}\mathrm{P}$ signals and the magnetic susceptibility vanishes, while DFT calculations evidence a bond alternation of the Ti-Ti distances within each chain. Thus, the 74 K phase transition is a spin-Peierls transition which evolves from an incommensurate phase existing between 111 and 74 K. DA - 2011/5/23/ PY - 2011/5/23/ DO - 10.1103/physrevb.83.180414 VL - 83 IS - 18 SP - SN - 1098-0121 ER - TY - JOUR TI - Special Issue: Green Communications and Networking AU - Dutta, Rudra AU - Schupke, Dominic AU - Somemura, Yoh T2 - OPTICAL SWITCHING AND NETWORKING DA - 2011/7// PY - 2011/7// DO - 10.1016/j.osn.2011.05.001 VL - 8 IS - 3 SP - 129-130 SN - 1573-4277 ER - TY - JOUR TI - QoS routing across multiple autonomous systems using the path computation element architecture AU - Geleji, Geza AU - Perros, Harry G. T2 - ANNALS OF TELECOMMUNICATIONS DA - 2011/6// PY - 2011/6// DO - 10.1007/s12243-010-0206-y VL - 66 IS - 5-6 SP - 293-306 SN - 1958-9395 KW - BGP KW - QoS KW - PCE KW - AS-path calculation algorithm ER - TY - JOUR TI - On the Levy-Walk Nature of Human Mobility AU - Rhee, Injong AU - Shin, Minsu AU - Hong, Seongik AU - Lee, Kyunghan AU - Kim, Seong Joon AU - Chong, Song T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - We report that human walk patterns contain statistically similar features observed in Levy walks. These features include heavy-tail flight and pause-time distributions and the super-diffusive nature of mobility. Human walks are not random walks, but it is surprising that the patterns of human walks and Levy walks contain some statistical similarity. Our study is based on 226 daily GPS traces collected from 101 volunteers in five different outdoor sites. The heavy-tail flight distribution of human mobility induces the super-diffusivity of travel, but up to 30 min to 1 h due to the boundary effect of people's daily movement, which is caused by the tendency of people to move within a predefined (also confined) area of daily activities. These tendencies are not captured in common mobility models such as random way point (RWP). To evaluate the impact of these tendencies on the performance of mobile networks, we construct a simple truncated Levy walk mobility (TLW) model that emulates the statistical features observed in our analysis and under which we measure the performance of routing protocols in delay-tolerant networks (DTNs) and mobile ad hoc networks (MANETs). The results indicate the following. Higher diffusivity induces shorter intercontact times in DTN and shorter path durations with higher success probability in MANET. The diffusivity of TLW is in between those of RWP and Brownian motion (BM). Therefore, the routing performance under RWP as commonly used in mobile network studies and tends to be overestimated for DTNs and underestimated for MANETs compared to the performance under TLW. DA - 2011/6// PY - 2011/6// DO - 10.1109/tnet.2011.2120618 VL - 19 IS - 3 SP - 630-643 SN - 1558-2566 KW - Delay-tolerant network (DTN) KW - human mobility KW - Levy walk KW - mobile ad hoc network (MANET) KW - mobile network KW - mobility model ER - TY - CONF TI - Methodology for engineering affective social applications AU - Sollenberger, D. J. AU - Singh, M. P. C2 - 2011/// C3 - Agent-oriented software engineering x DA - 2011/// VL - 6038 SP - 97-109 ER - TY - JOUR TI - Inferring specifications for resources from natural language API documentation AU - Zhong, Hao AU - Zhang, Lu AU - Xie, Tao AU - Mei, Hong T2 - AUTOMATED SOFTWARE ENGINEERING DA - 2011/12// PY - 2011/12// DO - 10.1007/s10515-011-0082-3 VL - 18 IS - 3-4 SP - 227-261 SN - 1573-7535 KW - Inferring specifications KW - API documentation ER - TY - JOUR TI - Episodic radiations in the fly tree of life AU - Wiegmann, B. M. AU - Trautwein, M. D. AU - Winkler, I. S. AU - Barr, N. B. AU - Kim, J. W. AU - Lambkin, C. AU - Bertone, M. A. AU - Cassel, B. K. AU - Bayless, K. M. AU - Heimberg, A. M. AU - Wheeler, B. M. AU - Peterson, K. J. AU - Pape, T. AU - Sinclair, B. J. AU - Skevington, J. H. AU - Blagoderov, V. T2 - Proceedings of the National Academy of Sciences of the United States of America DA - 2011/// PY - 2011/// VL - 108 IS - 14 SP - 5690-5695 ER - TY - JOUR TI - Alattin: mining alternative patterns for defect detection AU - Thummalapenta, Suresh AU - Xie, Tao T2 - AUTOMATED SOFTWARE ENGINEERING AB - To improve software quality, static or dynamic defect-detection tools accept programming rules as input and detect their violations in software as defects. As these programming rules are often not well documented in practice, previous work developed various approaches that mine programming rules as frequent patterns from program source code. Then these approaches use static or dynamic defect-detection techniques to detect pattern violations in source code under analysis. However, these existing approaches often produce many false positives due to various factors. To reduce false positives produced by these mining approaches, we develop a novel approach, called Alattin, that includes new mining algorithms and a technique for detecting neglected conditions based on our mining algorithm. Our new mining algorithms mine patterns in four pattern formats: conjunctive, disjunctive, exclusive-disjunctive, and combinations of these patterns. We show the benefits and limitations of these four pattern formats with respect to false positives and false negatives among detected violations by applying those patterns to the problem of detecting neglected conditions. DA - 2011/12// PY - 2011/12// DO - 10.1007/s10515-011-0086-z VL - 18 IS - 3-4 SP - 293-323 SN - 1573-7535 KW - Alternative patterns KW - Static defect detection KW - Mining software engineering data KW - Code search engine ER - TY - JOUR TI - Self-Renewing Applications AU - Singh, Munindar P. T2 - IEEE INTERNET COMPUTING AB - Software practice has suffered from and continues to suffer from many shortcomings as a result. Programs are difficult to design and build; they often fail to satisfy user requirements. If they work adequately at all, it's more often due to users adapting to the program than the program meeting users' requirements. The thesis of this column is that software engineering would be well served if we began to think of application-as-use as primary. In particular, if we could develop user interactions correctly, the application-as-use of a software artifact would help renew that artifact. DA - 2011/// PY - 2011/// DO - 10.1109/mic.2011.95 VL - 15 IS - 4 SP - 3-5 SN - 1941-0131 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79959988653&partnerID=MN8TOARS ER - TY - CONF TI - Predictable task migration for locked caches in multi-core systems AU - Sarkar, A. AU - Mueller, F. AU - Ramaprasad, H. AB - Locking cache lines in hard real-time systems is a common means of achieving predictability of cache access behavior and tightening as well as reducing worst case execution time, especially in a multitasking environment. However, cache locking poses a challenge for multi-core hard real-time systems since theoretically optimal scheduling techniques on multi-core architectures assume zero cost for task migration. Tasks with locked cache lines need to proactively migrate these lines before the next invocation of the task. Otherwise, cache locking on multi-core architectures becomes useless as predictability is compromised. C2 - 2011/// C3 - LCTES 11: Proceedings of the ACM Sigplan/Sigbed 2011 Conference on Languages, Complilers, Tools and Theory for Embedded Systems DA - 2011/// DO - 10.1145/1967677.1967696 SP - 131-140 ER - TY - JOUR TI - Making DRAM refresh predictable AU - Bhat, Balasubramanya AU - Mueller, Frank T2 - REAL-TIME SYSTEMS AB - Embedded control systems with hard real-time constraints require that deadlines are met at all times or the system may malfunction with potentially catastrophic consequences. Schedulability theory can assure deadlines for a given task set when periods and worst-case execution times (WCETs) of tasks are known. While periods are generally derived from the problem specification, a task’s code needs to be statically analyzed to derive safe and tight bounds on its WCET. Such static timing analysis abstracts from program input and considers loop bounds and architectural features, such as pipelining and caching. However, unpredictability due to dynamic memory (DRAM) refresh cannot be accounted for by such analysis, which limits its applicability to systems with static memory (SRAM). In this paper, we assess the impact of DRAM refresh on task execution times and demonstrate how predictability is adversely affected leading to unsafe hard real-time system design. We subsequently contribute a novel and effective approach to overcome this problem through software-initiated DRAM refresh. We develop (1) a pure software and (2) a hybrid hardware/software refresh scheme. Both schemes provide predictable timings and fully replace the classical hardware auto-refresh. We discuss implementation details based on this design for multiple concrete embedded platforms and experimentally assess the benefits of different schemes on these platforms. We further formalize the integration of variable latency memory references into a data-flow framework suitable for static timing analysis to bound a task’s memory latencies with regard to their WCET. The resulting predictable execution behavior in the presence of DRAM refresh combined with the additional benefit of reduced access delays is unprecedented, to the best of our knowledge. DA - 2011/9// PY - 2011/9// DO - 10.1007/s11241-011-9129-6 VL - 47 IS - 5 SP - 430-453 SN - 1573-1383 KW - Real-time systems KW - DRAM KW - Worst-case execution time KW - Timing analysis KW - DRAM refresh KW - Timing predictability ER - TY - JOUR TI - A practical fair queuing scheduler: Simplification through quantization AU - Dwekat, Z. AU - Rouskas, G. N. T2 - COMPUTER NETWORKS AB - The design of fair packet schedulers involves a tradeoff between implementation complexity, on one hand, and delay and fairness guarantees, on the other. In this paper, we present tiered-service fair queuing (TSFQ), a new scheduler that exploits certain properties of Internet traffic to speed up the bottleneck operations related to virtual time computation and packet sorting. Specifically, TSFQ makes innovative use of quantization (along the two dimensions of flow weights and packet lengths) her with specialized yet simple queuing structures. TSFQ combines all three properties that are important to a fair queuing algorithm, namely, a tight delay bound, worst-case fairness, and low complexity and amenability to hardware implementation. Hence, we believe that, for network operators, deploying TSFQ scheduling has the potential to enhance their ability to offer and guarantee a wide range of services. DA - 2011/7/14/ PY - 2011/7/14/ DO - 10.1016/j.comnet.2011.04.004 VL - 55 IS - 10 SP - 2392-2406 SN - 1872-7069 KW - Packet scheduling KW - Fair queuing KW - Tiered service ER - TY - JOUR TI - Online algorithms for advance resource reservations AU - Castillo, C. AU - Rouskas, G. N. AU - Harfoush, K. T2 - JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING AB - We consider the problem of providing QoS guarantees to Grid users through advance reservation of resources. Advance reservation mechanisms provide the ability to allocate resources to users based on agreed-upon QoS requirements and increase the predictability of a Grid system, yet incorporating such mechanisms into current Grid environments has proven to be a challenging task due to the resulting resource fragmentation. We use concepts from computational geometry to present a framework for tackling the resource fragmentation, and for formulating a suite of scheduling strategies. We also develop efficient implementations of the scheduling algorithms that scale to large Grids. We conduct a comprehensive performance evaluation study using simulation, and we present numerical results to demonstrate that our strategies perform well across several metrics that reflect both user- and system-specific goals. Our main contribution is a timely, practical, and efficient solution to the problem of scheduling resources in emerging on-demand computing environments. DA - 2011/7// PY - 2011/7// DO - 10.1016/j.jpdc.2011.01.003 VL - 71 IS - 7 SP - 963-973 SN - 1096-0848 KW - Grid computing KW - Advance reservations KW - Scheduling KW - Resource allocation KW - Resource management ER - TY - JOUR TI - Robust Correlation of Encrypted Attack Traffic through Stepping Stones by Flow Watermarking AU - Wang, Xinyuan AU - Reeves, Douglas S. T2 - IEEE TRANSACTIONS ON DEPENDABLE AND SECURE COMPUTING AB - Network-based intruders seldom attack their victims directly from their own computer. Often, they stage their attacks through intermediate “stepping stones” in order to conceal their identity and origin. To identify the source of the attack behind the stepping stone(s), it is necessary to correlate the incoming and outgoing flows or connections of a stepping stone. To resist attempts at correlation, the attacker may encrypt or otherwise manipulate the connection traffic. Timing-based correlation approaches have been shown to be quite effective in correlating encrypted connections. However, timing-based correlation approaches are subject to timing perturbations that may be deliberately introduced by the attacker at stepping stones. In this paper, we propose a novel watermark-based-correlation scheme that is designed specifically to be robust against timing perturbations. Unlike most previous timing-based correlation approaches, our watermark-based approach is “active” in that it embeds a unique watermark into the encrypted flows by slightly adjusting the timing of selected packets. The unique watermark that is embedded in the encrypted flow gives us a number of advantages over passive timing-based correlation in resisting timing perturbations by the attacker. In contrast to the existing passive correlation approaches, our active watermark-based correlation does not make any limiting assumptions about the distribution or random process of the original interpacket timing of the packet flow. In theory, our watermark-based correlation can achieve arbitrarily close to 100 percent correlation true positive rate (TPR), and arbitrarily close to 0 percent false positive rate (FPR) at the same time for sufficiently long flows, despite arbitrarily large (but bounded) timing perturbations of any distribution by the attacker. Our paper is the first that identifies 1) accurate quantitative tradeoffs between the achievable correlation effectiveness and the defining characteristics of the timing perturbation; and 2) a provable upper bound on the number of packets needed to achieve a desired correlation effectiveness, given the amount of timing perturbation. Experimental results show that our active watermark-based correlation performs better and requires fewer packets than existing, passive timing-based correlation methods in the presence of random timing perturbations. DA - 2011/// PY - 2011/// DO - 10.1109/tdsc.2010.35 VL - 8 IS - 3 SP - 434-449 SN - 1941-0018 KW - Network-level security and protection KW - intrusion tracing KW - correlation KW - stepping stone ER - TY - JOUR TI - On the parameterized complexity of the Multi-MCT and Multi-MCST problems AU - Chen, Wenbin AU - Schmidt, Matthew C. AU - Samatova, Nagiza F. T2 - JOURNAL OF COMBINATORIAL OPTIMIZATION DA - 2011/2// PY - 2011/2// DO - 10.1007/s10878-009-9220-2 VL - 21 IS - 2 SP - 151-158 SN - 1573-2886 KW - Multi-MCT KW - Multi-MCST KW - W-hierarchy KW - Parameterized complexity KW - Computational complexity ER - TY - JOUR TI - Digital privacy: theory, policies and technologies AU - Anton, Annie I. AU - Breaux, Travis D. AU - Gritzalis, Stefanos AU - Mylopoulos, John T2 - REQUIREMENTS ENGINEERING AB - 1 Digital privacy: theory, policies and technologiesInformation and communication technologies (ICT) con-tinue to evolve at a remarkably high pace. As a result, moreindividuals use ICT at work and at home, carrying outroutine daily tasks such as on-line shopping, banking andsocial interaction. Unfortunately, increased use of ICT hasresulted in increased risk that individuals’ privacy rightswill be violated. These risks to privacy include violationsof user anonymity during sensitive transactions, unautho-rized disclosures of personal data, misuse of personal datafor unauthorized purposes, misrepresentation of personalcharacter and more.To comply with privacy laws, regulations and policies,we need to develop techniques for identifying, document-ing and testing privacy requirements that are feasible andefficient to implement. Moreover, developers need toupdate their software processes to ensure that privacy is notan afterthought whereby privacy measures become an add-on or employed in an ad hoc or arbitrary fashion. Finally,organizations that manage personal information mustintegrate privacy-enabled technologies and processes intotheir business practices to comply with emerginglegislation.This special issue of the Springer’s RequirementsEngineering journal aims at providing researchers andprofessionals with insights into the state-of-the-art inDigital Privacy from the views of Theory, Policies andTechnologies.2 The content of this special issueThe papers presented in this special issue contribute to theaforementioned research directions. The four papers pre-sented in this special issue have been selected following athorough review process of 16 submissions that respondedto the Call for Papers which was distributed. Each of thepapers was reviewed by at least three reviewers, with arange from three to five reviewers, in two review stages.In their paper entitled ‘A privacy threat analysisframework: Supporting the elicitation and fulfillment ofprivacy requirements’, M. Deng, K. Wuyts, R. Scandariato,B. Preneel and W. Joosen provide a framework to modelprivacy threats in software-based systems, which includes asystematic methodology to model privacy-specific threats.The methodology instructs the analyst on what issuesshould be investigated and where in the model those issues DA - 2011/3// PY - 2011/3// DO - 10.1007/s00766-011-0117-0 VL - 16 IS - 1 SP - 1-2 SN - 1432-010X ER - TY - JOUR TI - Commitment analysis to operationalize software requirements from privacy policies AU - Young, Jessica D. T2 - Requirements Engineering DA - 2011/3// PY - 2011/3// DO - 10.1007/s00766-010-0108-6 VL - 16 IS - 1 SP - 33–46 SN - 0947-3602 1432-010X UR - http://dx.doi.org/10.1007/s00766-010-0108-6 KW - Requirement KW - Privacy policy KW - Compliance KW - Privacy aware KW - Commitment KW - Privilege KW - Right ER - TY - JOUR TI - A Probabilistic Approach for Maintaining Trust Based on Evidence AU - Wang, Yonghong AU - Hang, Chung-Wei AU - Singh, Munindar P. T2 - JOURNAL OF ARTIFICIAL INTELLIGENCE RESEARCH AB - Leading agent-based trust models address two important needs. First, they show how an agent may estimate the trustworthiness of another agent based on prior interactions. Second, they show how agents may share their knowledge in order to cooperatively assess the trustworthiness of others. However, in real-life settings, information relevant to trust is usually obtained piecemeal, not all at once. Unfortunately, the problem of maintaining trust has drawn little attention. Existing approaches handle trust updates in a heuristic, not a principled, manner. This paper builds on a formal model that considers probability and certainty as two dimensions of trust. It proposes a mechanism using which an agent can update the amount of trust it places in other agents on an ongoing basis. This paper shows via simulation that the proposed approach (a) provides accurate estimates of the trustworthiness of agents that change behavior frequently; and (b) captures the dynamic behavior of the agents. This paper includes an evaluation based on a real dataset drawn from Amazon Marketplace, a leading e-commerce site. DA - 2011/// PY - 2011/// DO - 10.1613/jair.3108 VL - 40 SP - 221-267 SN - 1943-5037 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-79956343086&partnerID=MN8TOARS ER - TY - JOUR TI - Trustworthy Service Selection and Composition AU - Hang, Chung-Wei AU - Singh, Munindar P. T2 - ACM Transactions on Autonomous and Adaptive Systems AB - We consider Service-Oriented Computing (SOC) environments. Such environments are populated with services that stand proxy for a variety of information resources. A fundamental challenge in SOC is to select and compose services, to support specified user needs directly or by providing additional services. Existing approaches for service selection either fail to capture the dynamic relationships between services or assume that the environment is fully observable. In practical situations, however, consumers are often not aware of how the services are implemented. We propose two distributed trust-aware service selection approaches: one based on Bayesian networks and the other on a beta-mixture model. We experimentally validate our approach through a simulation study. Our results show that both approaches accurately punish and reward services in terms of the qualities they offer, and further that the approaches are effective despite incomplete observations regarding the services under consideration. DA - 2011/2/1/ PY - 2011/2/1/ DO - 10.1145/1921641.1921646 VL - 6 IS - 1 SP - 1-17 J2 - ACM Trans. Auton. Adapt. Syst. LA - en OP - SN - 1556-4665 UR - http://dx.doi.org/10.1145/1921641.1921646 DB - Crossref KW - Algorithms KW - Experimentation KW - Trust KW - probabilistic modeling KW - service-oriented computing ER - TY - JOUR TI - Transparent runtime parallelization of the R scripting language AU - Li, Jiangtian AU - Ma, Xiaosong AU - Yoginath, Srikanth AU - Kora, Guruprasad AU - Samatova, Nagiza F. T2 - JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING AB - Scripting languages such as R and Matlab are widely used in scientific data processing. As the data volume and the complexity of analysis tasks both grow, sequential data processing using these tools often becomes the bottleneck in scientific workflows. We describe pR, a runtime framework for automatic and transparent parallelization of the popular R language used in statistical computing. Recognizing scripting languages’ interpreted nature and data analysis codes’ use pattern, we propose several novel techniques: (1) applying parallelizing compiler technology to runtime, whole-program dependence analysis of scripting languages, (2) incremental code analysis assisted with evaluation results, and (3) runtime parallelization of file accesses. Our framework does not require any modification to either the source code or the underlying R implementation. Experimental results demonstrate that pR can exploit both task and data parallelism transparently and overall has better performance as well as scalability compared to an existing parallel R package that requires code modification. DA - 2011/2// PY - 2011/2// DO - 10.1016/j.jpdc.2010.08.013 VL - 71 IS - 2 SP - 157-168 SN - 1096-0848 KW - Runtime parallelization KW - Incremental analysis KW - Scripting languages ER - TY - JOUR TI - SeCA: A framework for Secure Channel Assignment in wireless mesh networks AU - Kim, Mihui AU - Ning, Peng T2 - COMPUTER COMMUNICATIONS AB - To maximize the available throughput in multi-channel multi-radio wireless mesh networks (WMNs), it is a critical issue to design a channel assignment scheme efficiently utilizing orthogonal channels. However, most channel assignment schemes are vulnerable to the misbehaviors of nodes participating in channel assignment, and existing secure channel assignment schemes do not address all of the vulnerabilities. In this paper, we address the threats to channel assignment in WMNs resulting from node misbehaviors and present a generic verification framework to detect such misbehaviors. We develop a concrete verification scheme based on this framework and an existing distributed channel assignment scheme. We validate our approach by implementing the verification scheme and evaluating it through simulation. The results show that our approach improves misbehavior detection with minimum performance overhead. DA - 2011/4/1/ PY - 2011/4/1/ DO - 10.1016/j.comcom.2010.05.008 VL - 34 IS - 4 SP - 567-576 SN - 1873-703X KW - Secure channel assignment KW - Multi-channel multi-radio KW - Wireless mesh networks KW - Relay attack resistance KW - Misbehavior resistance ER - TY - JOUR TI - Data-intensive document clustering on graphics processing unit (GPU) clusters AU - Zhang, Yongpeng AU - Mueller, Frank AU - Cui, Xiaohui AU - Potok, Thomas T2 - JOURNAL OF PARALLEL AND DISTRIBUTED COMPUTING AB - Document clustering is a central method to mine massive amounts of data. Due to the explosion of raw documents generated on the Internet and the necessity to analyze them efficiently in various intelligent information systems, clustering techniques have reached their limitations on single processors. Instead of single processors, general-purpose multi-core chips are increasingly deployed in response to diminishing returns in single-processor speedup due to the frequency wall, but multi-core benefits only provide linear speedups while the number of documents in the Internet is growing exponentially. Accelerating hardware devices represent a novel promise for improving the performance for data-intensive problems such as document clustering. They offer more radical designs with a higher level of parallelism but adaptation to novel programming environments. In this paper, we assess the benefits of exploiting the computational power of graphics processing units (GPUs) to study two fundamental problems in document mining, namely to calculate the term frequency-inverse document frequency (TF-IDF) and cluster a large set of documents. We transform traditional algorithms into accelerated parallel counterparts that can be efficiently executed on many-core GPU architectures. We assess our implementations on various platforms, ranging from stand-alone GPU desktops to Beowulf-like clusters equipped with contemporary GPU cards. We observe at least one order of magnitude speedups over CPU-only desktops and clusters. This demonstrates the potential of exploiting GPU clusters to efficiently solve massive document mining problems. Such speedups combined with the scalability potential and accelerator-based parallelization are unique in the domain of document-based data mining, to the best of our knowledge. DA - 2011/2// PY - 2011/2// DO - 10.1016/j.jpdc.2010.08.002 VL - 71 IS - 2 SP - 211-224 SN - 1096-0848 KW - High-performance computing KW - Accelerators KW - Data-intensive computing ER - TY - JOUR TI - Coordinating Computation and I/O in Massively Parallel Sequence Search AU - Lin, Heshan AU - Ma, Xiaosong AU - Feng, Wuchun AU - Samatova, Nagiza F. T2 - IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS AB - With the explosive growth of genomic information, the searching of sequence databases has emerged as one of the most computation and data-intensive scientific applications. Our previous studies suggested that parallel genomic sequence-search possesses highly irregular computation and I/O patterns. Effectively addressing these runtime irregularities is thus the key to designing scalable sequence-search tools on massively parallel computers. While the computation scheduling for irregular scientific applications and the optimization of noncontiguous file accesses have been well-studied independently, little attention has been paid to the interplay between the two. In this paper, we systematically investigate the computation and I/O scheduling for data-intensive, irregular scientific applications within the context of genomic sequence search. Our study reveals that the lack of coordination between computation scheduling and I/O optimization could result in severe performance issues. We then propose an integrated scheduling approach that effectively improves sequence-search throughput by gracefully coordinating the dynamic load balancing of computation and high-performance noncontiguous I/O. DA - 2011/4// PY - 2011/4// DO - 10.1109/tpds.2010.101 VL - 22 IS - 4 SP - 529-543 SN - 1558-2183 KW - Scheduling KW - parallel I/O KW - bioinformatics KW - parallel genomic sequence search KW - BLAST ER - TY - JOUR TI - P(2)DAP - Sybil Attacks Detection in Vehicular Ad Hoc Networks AU - Zhou, Tong AU - Roy, Romit AU - Ning, Choudhury Peng AU - Chakrabarty, Krishnendu T2 - IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS AB - Vehicular ad hoc networks (VANETs) are being increasingly advocated for traffic control, accident avoidance, and management of parking lots and public areas. Security and privacy are two major concerns in VANETs. Unfortunately, in VANETs, most privacy-preserving schemes are vulnerable to Sybil attacks, whereby a malicious user can pretend to be multiple (other) vehicles. In this paper, we present a lightweight and scalable protocol to detect Sybil attacks. In this protocol, a malicious user pretending to be multiple (other) vehicles can be detected in a distributed manner through passive overhearing by s set of fixed nodes called road-side boxes (RSBs). The detection of Sybil attacks in this manner does not require any vehicle in the network to disclose its identity; hence privacy is preserved at all times. Simulation results are presented for a realistic test case to highlight the overhead for a centralized authority such as the DMV, the false alarm rate, and the detection latency. The results also quantify the inherent trade-off between security, i.e., the detection of Sybil attacks and detection latency, and the privacy provided to the vehicles in the network. From the results, we see our scheme being able to detect Sybil attacks at low overhead and delay, while preserving privacy of vehicles. DA - 2011/3// PY - 2011/3// DO - 10.1109/jsac.2011.110308 VL - 29 IS - 3 SP - 582-594 SN - 0733-8716 KW - Coarse-grained hash KW - fine-grained hash KW - privacy KW - security KW - Sybil attack KW - vehicular ad hoc network ER -