TY - CONF TI - Configuration Management at Massive Scale: System Design and Experience AU - Enck, William AU - McDaniel, Patrick AU - Sen, Subhabrata AU - Sebos, Panagiotis AU - Spoerel, Sylke AU - Greenberg, Albert AU - Rao, Sanjay AU - Aiello, William T2 - USENIX Annual Technical Conference C2 - 2007/// C3 - Proceedings of the USENIX Annual Technical Conference CY - Santa Clara, CA DA - 2007/// PY - 2007/// SP - 73-86 UR - https://www.usenix.org/legacy/events/usenix07/tech/enck.html ER - TY - CONF TI - Protecting users from themselves AU - Enck, William AU - Rueda, Sandra AU - Schiffman, Joshua AU - Sreenivasan, Yogesh AU - St Clair, Luke AU - Jaeger, Trent AU - McDaniel, Patrick T2 - ACM C2 - 2007/// C3 - Proceedings of the 2007 ACM workshop on Computer security architecture DA - 2007/// SP - 29-36 ER - TY - CONF TI - Limiting sybil attacks in structured p2p networks AU - Rowaihy, Hosam AU - Enck, William AU - McDaniel, Patrick AU - La Porta, Thomas T2 - IEEE C2 - 2007/// C3 - INFOCOM 2007. 26th IEEE International Conference on Computer Communications. IEEE DA - 2007/// SP - 2596-2600 ER - TY - RPRT TI - Grains of SANs: Building Storage Area Networks from Memory Spots AU - Johansen, Lisa AU - Butler, Kevin AU - Enck, William AU - Traynor, Patrick AU - McDaniel, Patrick A3 - Technical Report NASTR-0060-2007, Network and Security Research Center … DA - 2007/// PY - 2007/// PB - Technical Report NASTR-0060-2007, Network and Security Research Center … ER - TY - CONF TI - Using groupings of static analysis alerts to identify files likely to contain field failures AU - Sherriff, Mark S AU - Heckman, Sarah Smith AU - Lake, J Michael AU - Williams, Laurie A C2 - 2007/// C3 - The 6th Joint Meeting on European software engineering conference and the ACM SIGSOFT symposium on the foundations of software engineering: companion papers DA - 2007/// SP - 565-568 ER - TY - CONF TI - Identifying fault-prone files using static analysis alerts through singular value decomposition AU - Sherriff, Mark AU - Heckman, Sarah Smith AU - Lake, Mike AU - Williams, Laurie T2 - IBM Corp. C2 - 2007/// C3 - Proceedings of the 2007 conference of the center for advanced studies on Collaborative research DA - 2007/// SP - 276-279 ER - TY - JOUR TI - Adaptively ranking alerts generated from automated static analysis AU - Heckman, Sarah Smith T2 - XRDS: Crossroads, The ACM Magazine for Students DA - 2007/// PY - 2007/// VL - 14 IS - 1 SP - 1-11 ER - TY - CONF TI - Adaptive probabilistic model for ranking code-based static analysis alerts AU - Heckman, Sarah Smith T2 - IEEE C2 - 2007/// C3 - 29th International Conference on Software Engineering (ICSE'07 Companion) DA - 2007/// SP - 89-90 ER - TY - CONF TI - Proceedings of the ACM/SIGSOFT International Symposium on Software Testing and Analysis, ISSTA 2007, London, UK, July 9-12, 2007 A2 - Rosenblum, David S. A2 - Elbaum, Sebastian G. C2 - 2007/// DA - 2007/// DO - 10.1145/1273463 PB - ACM UR - http://doi.acm.org/10.1145/1273463 ER - TY - CONF TI - Delta execution for efficient state-space exploration of object-oriented programs AU - d’Amorim, Marcelo AU - Lauterburg, Steven AU - Marinov, Darko AB - State-space exploration is the essence of model checking and an increasingly popular approach for automating test generation. A key issue in exploration of object-oriented programs is handling the program state, in particular the heap. Previous research has focused on standard program execution that operates on one state/heap. We present Delta Execution, a technique that simultaneously operates on several states/heaps. It exploits the fact that many execution paths in state-space exploration partially overlap and speeds up the exploration by sharing the common parts across the executions and separately executing only the "deltas" where the executions differ. C2 - 2007/// C3 - Proceedings of the ACM/SIGSOFT International Symposium on Software Testing and Analysis, ISSTA 2007, London, UK, July 9-12, 2007 DA - 2007/// DO - 10.1145/1273463.1273472 SP - 50-60 UR - http://doi.acm.org/10.1145/1273463.1273472 ER - TY - JOUR TI - The SILO architecture for services integration, control, and optimization for the future Internet AU - Dutta, Rudra AU - Rouskas, George N. AU - Baldine, Ilia AU - Bragg, Arnold AU - Stevenson, Dan AU - IEEE T2 - 2007 Ieee International Conference on Communications, Vols 1-14 AB - We propose a new internetworking architecture that represents a departure from current philosophy and practice, as a contribution to the ongoing debate regarding the future Internet. Building upon our experience with the design and prototyping of the just-in-time protocol suite, we outline a framework consisting of (1) building blocks of fine-grain functionality, (2) explicit support for combining elemental blocks to accomplish highly configurable complex communication tasks, and (3) control elements to facilitate (what is currently referred to as) cross-layer interactions. In this position paper, we take a holistic view of network design, allowing applications to work synergistically with the network architecture and physical layers to select the most appropriate functional blocks and tune their behavior so as to meet the application's needs within resource availability constraints. The proposed architecture is flexible and extensible so as to foster innovation and accommodate change, it supports a unified Internet, it allows for the integration of security and management features at any point in (what is now referred to as) the networking stack, and it is positioned to take advantage of hardware-based performance-enhancing techniques. DA - 2007/// PY - 2007/// DO - 10.1109/ICC.2007.316 SP - 1899-1904 ER - TY - JOUR TI - TDM emulation in packet-switched networks AU - Rouskas, George N. AU - BaradwaJ, Nikhil AU - IEEE T2 - 2007 Ieee International Conference on Communications, Vols 1-14 AB - Many network operators offer some type of tiered service, in which users may select only from a small set of service levels (tiers). In this work, we study the problem of designing a tiered-service network that allocates bandwidth in multiples of a basic bandwidth unit. Such a packet-switched network can enjoy many of the benefits, in terms of control and management, of a TDM network, but without the associated data plane rigidities. DA - 2007/// PY - 2007/// DO - 10.1109/ICC.2007.318 SP - 1911-1916 ER - TY - JOUR TI - On the suitability of composable services for the assurable future Internet AU - Stevenson, Daniel AU - Dutta, Rudra AU - Rouskas, George AU - Reeves, Douglas AU - Baldine, Ilia AU - IEEE T2 - 2007 Ieee Military Communications Conference, Vols 1-8 DA - 2007/// PY - 2007/// SP - 3695-3701 ER - TY - JOUR TI - Hierarchical Grooming in Multigranular Networks AU - Iyer, Mohan AU - Rouskas, George N. AU - Dutta, Rudra AU - IEEE T2 - 2007 First International Symposium on Advanced Networks and Telecommunication Systems DA - 2007/// PY - 2007/// SP - 35-36 ER - TY - JOUR TI - Framework for tiered service in MPLS networks AU - Rouskas, George N. AU - Baradwaj, Nikhil AU - IEEE T2 - Infocom 2007, Vols 1-5 AB - Many network operators offer some type of tiered service, in which users may select only from a small set of service levels (tiers). Such a service has the potential to simplify a wide range of core network functions, allowing the providers to scale their operations efficiently. In this work, we provide a theoretical framework for reasoning about and tackling algorithmically the general problem of service tier selection. Drawing upon results from discrete location theory, we formulate the problem as a p -median problem under a new directional distance measure, and we develop efficient algorithms for a number of important variants. Our main finding is that, by appropriately selecting the set of service levels, network providers may realize the benefits of tiered service with only a small sacrifice in network resources. DA - 2007/// PY - 2007/// DO - 10.1109/INFCOM.2007.185 SP - 1577-1585 ER - TY - CHAP TI - Clustering for hierarchical traffic grooming in large scale mesh WDM networks AU - Chen, Bensong AU - Dutta, Rudra AU - Rouskas, George N. AU - Tomkos, I AU - Neri, F AU - Pareta, JS AU - Bruin, XM AU - Lopez, SS T2 - Optical Network Design and Modeling, Proceedings PY - 2007/// VL - 4534 SP - 249-258 PB - SE - ER - TY - CHAP TI - A unified software architecture to enable cross-layer design in the future Internet AU - Baldine, Ilia AU - Vellala, Manoj AU - Wang, Anjing AU - Rouskas, George AU - Dutta, Rudra AU - Stevenson, Daniel AU - IEEE T2 - Proceedings - 16th International Conference on Computer Communications and Networks, Vols 1-3 PY - 2007/// SP - 26-32 PB - SE - ER - TY - JOUR TI - A practical and efficient implementation of WF(2)Q+ AU - Rouskas, George N. AU - Dwekat, Zyad AU - IEEE T2 - 2007 Ieee International Conference on Communications, Vols 1-14 AB - The WF 2 Q+ scheduler combines all three properties that are important to a fair queueing algorithm: a tight delay bound, a small worst-case fair index value, and a relatively low worst-case complexity of O ( log n ) for a link with n flows. We present a new implementation of WF 2 Q+ in which both the number of packet sorting operations and the computation of the virtual time function are independent of the number n of flows. Our implementation exploits two widely observed characteristics of the Internet, namely that service providers offer some type of tiered service with a small number of service levels, and that a small number of packet sizes dominate. Our scheduler combines provably good performance with amenability to hardware implementation in high-speed routers. DA - 2007/// PY - 2007/// DO - 10.1109/ICC.2007.36 SP - 172-176 ER - TY - RPRT TI - THU and ICRC at TRECVID 2007 AU - Yuan, Jinhui AU - Guo, Zhishan AU - Lv, Li AU - Wan, Wei AU - Zhang, Teng AU - Wang, Dong AU - Liu, Xiaobing AU - Liu, Cailiang AU - Zhu, Shengqi AU - Wang, Duanpeng AU - Pang, Yang AU - Ding, Nan AU - Liu, Ying AU - Wang, Jiangping AU - Zhang, Xiujun AU - Tie, Xiaozheng AU - Wang, Zhikun AU - Wang, Huiyi AU - Xiao, Tongchun AU - Liang, Yinyu AU - Li, Jianmin AU - Lin, Fuzong AU - Zhang, Bo AU - Li, JianGuo AU - Wu, WeiXin AU - Tong, XiaoFeng AU - Ding, DaYong AU - Chen, YuRong AU - Wang, Tao AU - Zhang, Yimin A3 - National Institute of Standards and Technology DA - 2007/// PY - 2007/// PB - National Institute of Standards and Technology ER - TY - JOUR TI - Session details: Embedded systems and architecture AU - Gehringer, Edward T2 - ACM SIGCSE Bulletin AB - No abstract available. DA - 2007/3/7/ PY - 2007/3/7/ DO - 10.1145/3263059 VL - 39 IS - 1 ER - TY - CONF TI - Lower bounds for approximate factorizations via semidefinite programming AU - Kaltofen, Erich AU - Li, Bin AU - Sivaramakrishnan, Kartik AU - Yang, Zhengfeng AU - Zhi, Lihong T2 - International Workshop on Symbolic-Numeric Computation A2 - Verschelde, Jan A2 - Watt, Stephen M. C2 - 2007/// C3 - Proceedings of the 2007 International Workshop on Symbolic-Numeric Computation (SNC '07) CY - London, Ontario, Canada DA - 2007/// PY - 2007/7/25/ SP - 203–204 PB - ACM Press SN - 9781595937445 ER - TY - ER - TY - ER - TY - CHAP TI - Performance Analysis of Traffic-Groomed Optical Networks Employing Alternate Routing Techniques AU - Washington, Nicki AU - Perros, Harry T2 - Managing Traffic Performance in Converged Networks. ITC 2007 A2 - Mason, L. A2 - Drwiega, T. A2 - Yan, J. T3 - Lecture Notes in Computer Science PY - 2007/9/1/ DO - 10.1007/978-3-540-72990-7_90 SP - 1048–1059 PB - Springer SN - 9783540729891 SV - 4516 UR - http://dx.doi.org/10.1007/978-3-540-72990-7_90 ER - TY - CHAP TI - Analysis and Provisioning of a Circuit-Switched Link with Variable-Demand Customers AU - Tian, Wenhong AU - Perros, Harry T2 - Managing Traffic Performance in Converged Networks. ITC 2007 A2 - Mason, L. A2 - Drwirga, T. A2 - Yan, J. T3 - Lecture Notes in Computer Science AB - We consider a single circuit-switched communication link, depicted by a Erlang multi-class loss queue, where a customer may vary its required bandwidth during its service. We obtain approximately the steady-state blocking probability of each class of customer. Comparisons with simulation results show that the approximation solution has a good accuracy. For the proposed model, we also provide an efficient capacity provisioning algorithm. PY - 2007/9/1/ DO - 10.1007/978-3-540-72990-7_77 SP - 890–900 PB - Springer SN - 9783540729891 SV - 4516 UR - http://dx.doi.org/10.1007/978-3-540-72990-7_77 ER - TY - CHAP TI - Roadmapping Working Group 4 Results AU - Williams, Laurie AU - Erdogmus, Hakan AU - Selby, Rick T2 - Empirical Software Engineering Issues. Critical Assessment and Future Directions A2 - Basili, V.R. A2 - Rombach, D. A2 - Schneider, K. A2 - Kitchenham, B. A2 - Pfahl, D. A2 - Selby, R.W. T3 - Lecture Notes in Computer Science PY - 2007/6/10/ DO - 10.1007/978-3-540-71301-2_53 SP - 181–183 PB - Springer SN - 9783540713005 9783540713012 SV - 4336 UR - http://dx.doi.org/10.1007/978-3-540-71301-2_53 ER - TY - CHAP TI - Industry-Research Collaboration Working Group Results AU - Prechelt, Lutz AU - Williams, Laurie T2 - Empirical Software Engineering Issues. Critical Assessment and Future Directions A2 - Basili, V.R. A2 - Rombach, D. A2 - Schneider, K. A2 - Kitchenham, B. A2 - Pfahl, D. A2 - Selby, R.W. T3 - Lecture Notes in Computer Science PY - 2007/6/10/ DO - 10.1007/978-3-540-71301-2_46 SP - 153–157 PB - Springer SN - 9783540713005 9783540713012 SV - 4336 UR - http://dx.doi.org/10.1007/978-3-540-71301-2_46 ER - TY - CHAP TI - Structuring Families of Industrial Case Studies AU - Williams, Laurie T2 - Empirical Software Engineering Issues. Critical Assessment and Future Directions A2 - Basili, V.R. A2 - Rombach, D. A2 - Schneider, K. A2 - Kitchenham, B. A2 - Pfahl, D. A2 - Selby, R.W. T3 - Lecture Notes in Computer Science AB - Practitioners are most influenced by results of research conducted in industrial settings. Evidence of the efficacy of a software development practice or process is best obtained through a triangulation of research findings obtained through a variety of empirical studies in various contexts. The use of an evaluation framework can enable a family of related industrial case studies in different contexts to be metaanalyzed and/or combined. Such an evaluation framework could consists of templates for specific quantitative measures to collect with associated instructions on what to include/exclude for consistent measurement collection as well as protocols for surveys and/or interviews. Groups of researchers interested in the same research question(s) can customize and evolve an evaluation framework for the technology under study. PY - 2007/6/10/ DO - 10.1007/978-3-540-71301-2_41 SP - 134–134 PB - Springer SN - 9783540713005 9783540713012 SV - 4336 UR - http://dx.doi.org/10.1007/978-3-540-71301-2_41 ER - TY - RPRT TI - Modeling Relations Between Inputs and Dynamic Behavior for General Programs AU - Shen, Xipeng AU - Mao, Feng A3 - Computer Science Department, The College of William and Mary DA - 2007/7// PY - 2007/7// M1 - WM-CS-2007-07 PB - Computer Science Department, The College of William and Mary SN - WM-CS-2007-07 ER - TY - RPRT TI - CAPS: Contention-Aware Proactive Scheduling for CMPs AU - Shen, Xipeng AU - Jiang, Yunlian AU - Mao, Feng A3 - Computer Science Department, The College of William and Mary DA - 2007/// PY - 2007/// M1 - WM-CS-2007-09 M3 - Technical Report PB - Computer Science Department, The College of William and Mary SN - WM-CS-2007-09 ER - TY - RPRT TI - Study of the Effects of Program Inputs on Co-Scheduling AU - Jiang, Yunlian AU - Shen, Xipeng A3 - Computer Science Department, The College of William and Mary DA - 2007/7// PY - 2007/7// M1 - WM-CS-2007-13 M3 - Technical Report PB - Computer Science Department, The College of William and Mary SN - WM-CS-2007-13 ER - TY - RPRT TI - A Hybrid Framework Bridging Locality Analysis and Cache-Aware Scheduling for CMPs AU - Shen, Xipeng A3 - Computer Science Dept., The College of William and Mary DA - 2007/1// PY - 2007/1// M1 - WM-CS-2007-01 M3 - Technical Report PB - Computer Science Dept., The College of William and Mary SN - WM-CS-2007-01 ER - TY - CONF TI - Engaging viewers through nonphotorealistic visualizations AU - Tateosian, Laura G. AU - Healey, Christopher G. AU - Enns, James T. T2 - the 5th international symposium AB - Research in human visual cognition suggests that beautiful images can engage the visual system, encouraging it to linger in certain locations in an image and absorb subtle details. By developing aesthetically pleasing visualizations of data, we aim to engage viewers and promote prolonged inspection, which can lead to new discoveries within the data. We present three new visualization techniques that apply painterly rendering styles to vary interpretational complexity (IC), indication and detail (ID), and visual complexity (VC), image properties that are important to aesthetics. Knowledge of human visual perception and psychophysical models of aesthetics provide the theoretical basis for our designs. Computational geometry and nonphotorealistic algorithms are used to preprocess the data and render the visualizations. We demonstrate the techniques with visualizations of real weather and supernova data. C2 - 2007/// C3 - Proceedings of the 5th international symposium on Non-photorealistic animation and rendering - NPAR '07 DA - 2007/// DO - 10.1145/1274871.1274886 PB - ACM Press SN - 9781595936240 UR - http://dx.doi.org/10.1145/1274871.1274886 DB - Crossref ER - TY - JOUR TI - A performance study on optical burst switched networks: the ring topology AU - Xin, Yufeng AU - Battestilli, Lina T2 - Photonic Network Communications DA - 2007/6/13/ PY - 2007/6/13/ DO - 10.1007/s11107-007-0061-6 VL - 14 IS - 1 SP - 63-70 J2 - Photon Netw Commun LA - en OP - SN - 1387-974X 1572-8188 UR - http://dx.doi.org/10.1007/s11107-007-0061-6 DB - Crossref KW - optical burst switched networks KW - performance study ER - TY - JOUR TI - An efficient spatial semi-supervised learning algorithm AU - Vatsavai, Ranga Raju AU - Shekhar, Shashi AU - Burk, Thomas E. T2 - International Journal of Parallel, Emergent and Distributed Systems AB - We began by developing a semi-supervised learning method based on the expectation-maximization (EM) algorithm, and maximum likelihood and maximum a posteriori classifiers (MLC and MAP). This scheme utilizes a small set of labeled and a large number of unlabeled training samples. We conducted several experiments on multi-spectral images to understand the impact of unlabeled samples on the classification performance. Our study shows that although, in general, classification accuracy improves with the addition of unlabeled training samples, it is not guaranteed to achieve consistently higher accuracies unless sufficient care is exercised when designing a semi-supervised classifier. We also extended this semi-supervised framework to model spatial context through Markov random fields (MRF). Initial experiments showed an improved accuracy of the spatial semi-supervised algorithm (SSSL) over MLC, semi-supervised, and MRF classifiers. An efficient implementation is provided so that the SSSL can be applied in production environments. We also discuss some open research problems. DA - 2007/12// PY - 2007/12// DO - 10.1080/17445760701207546 VL - 22 IS - 6 SP - 427-437 J2 - International Journal of Parallel, Emergent and Distributed Systems LA - en OP - SN - 1744-5760 1744-5779 UR - http://dx.doi.org/10.1080/17445760701207546 DB - Crossref KW - Semi-supervised learning KW - MLC KW - MAP KW - EM KW - Random fields KW - image analysis KW - 62M40 KW - 68U10 ER - TY - JOUR TI - Miss Rate Prediction Across Program Inputs and Cache Configurations AU - Zhong, Yutao AU - Dropsho, Steven G. AU - Shen, Xipeng AU - Studer, Ahren AU - Ding, Chen T2 - IEEE Transactions on Computers AB - Improving cache performance requires understanding cache behavior. However, measuring cache performance for one or two data input sets provides little insight into how cache behavior varies across all data input sets and all cache configurations. This paper uses locality analysis to generate a parameterized model of program cache behavior. Given a cache size and associativity, this model predicts the miss rate for arbitrary data input set sizes. This model also identifies critical data input sizes where cache behavior exhibits marked changes. Experiments show this technique is within 2 percent of the hit rate for set associative caches on a set of floating-point and integer programs using array and pointer-based data structures. Building on the new model, this paper presents an interactive visualization tool that uses a three-dimensional plot to show miss rate changes across program data sizes and cache sizes and its use in evaluating compiler transformations. Other uses of this visualization tool include assisting machine and benchmark-set design. The tool can be accessed on the Web at http://www.cs.rochester.edu/research/locality DA - 2007/3// PY - 2007/3// DO - 10.1109/tc.2007.50 VL - 56 IS - 3 SP - 328-343 J2 - IEEE Trans. Comput. OP - SN - 0018-9340 UR - http://dx.doi.org/10.1109/tc.2007.50 DB - Crossref KW - cache memories KW - modeling techniques KW - performance analysis and design aids KW - compilers KW - optimization ER - TY - JOUR TI - Predicting locality phases for dynamic memory optimization AU - Shen, Xipeng AU - Zhong, Yutao AU - Ding, Chen T2 - Journal of Parallel and Distributed Computing AB - Dynamic data, cache, and memory adaptation can significantly improve program performance when they are applied on long continuous phases of execution that have dynamic but predictable locality. To support phase-based adaptation, this paper defines the concept of locality phases and describes a four-component analysis technique. Locality-based phase detection uses locality analysis and signal processing techniques to identify phases from the data access trace of a program; frequency-based phase marking inserts code markers that mark phases in all executions of the program; phase hierarchy construction identifies the structure of multiple phases; and phase-sequence prediction predicts the phase sequence from program input parameters. The paper shows the accuracy and the granularity of phase and phase-sequence prediction as well as its uses in dynamic data packing, memory remapping, and cache resizing. DA - 2007/7// PY - 2007/7// DO - 10.1016/j.jpdc.2007.01.010 VL - 67 IS - 7 SP - 783-796 J2 - Journal of Parallel and Distributed Computing LA - en OP - SN - 0743-7315 UR - http://dx.doi.org/10.1016/j.jpdc.2007.01.010 DB - Crossref KW - program phase prediction KW - phase hierarchy KW - locality analysis and optimization KW - reconfigurable architecture KW - dynamic optimization ER - TY - CONF TI - Locality approximation using time AU - Shen, Xipeng AU - Shaw, Jonathan AU - Meeker, Brian AU - Ding, Chen T2 - the 34th annual ACM SIGPLAN-SIGACT symposium AB - Reuse distance (i.e. LRU stack distance) precisely characterizes program locality and has been a basic tool for memory system research since the 1970s. However, the high cost of measuring has restricted its practical uses in performance debugging, locality analysis and optimizations of long-running applications.In this work, we improve the efficiency by exploring the connection between time and locality. We propose a statistical model that converts cheaply obtained time distance to the more costly reuse distance. Compared to the state-of-the-art technique, this approach reduces measuring time by a factor of 17, and approximates cache line reuses with over 99% accuracy and the cache miss rate with less than 0.4% average error for 12 SPEC 2000 integer and floating-point benchmarks. By exploiting the strong correlations between time and locality, this work makes precise locality as easy to obtain as data access frequency, and opens new opportunities for program optimizations. C2 - 2007/// C3 - Proceedings of the 34th annual ACM SIGPLAN-SIGACT symposium on Principles of programming languages - POPL '07 DA - 2007/// DO - 10.1145/1190216.1190227 PB - ACM Press SN - 1595935754 UR - http://dx.doi.org/10.1145/1190216.1190227 DB - Crossref ER - TY - CONF TI - Software behavior oriented parallelization AU - Ding, Chen AU - Shen, Xipeng AU - Kelsey, Kirk AU - Tice, Chris AU - Huang, Ruke AU - Zhang, Chengliang T2 - the 2007 ACM SIGPLAN conference AB - Many sequential applications are difficult to parallelize because of unpredictable control flow, indirect data access, and input-dependent parallelism. These difficulties led us to build a software system for behavior oriented parallelization (BOP), which allows a program to be parallelized based on partial information about program behavior, for example, a user reading just part of the source code, or a profiling tool examining merely one or few executions. C2 - 2007/// C3 - Proceedings of the 2007 ACM SIGPLAN conference on Programming language design and implementation - PLDI '07 DA - 2007/// DO - 10.1145/1250734.1250760 PB - ACM Press SN - 9781595936332 UR - http://dx.doi.org/10.1145/1250734.1250760 DB - Crossref KW - speculative parallelization KW - program behavior ER - TY - JOUR TI - TARP: Ticket-based address resolution protocol AU - Lootah, Wesam AU - Enck, William AU - McDaniel, Patrick T2 - Computer Networks AB - IP networks fundamentally rely on the Address Resolution Protocol (ARP) for proper operation. Unfortunately, vulnerabilities in ARP enable a raft of Internet Protocol (IP)-based impersonation, man-in-the-middle, or Denial of Service (DoS) attacks. Proposed countermeasures to these vulnerabilities have yet to simultaneously address backward compatibility and cost requirements. This paper introduces the Ticket-based Address Resolution Protocol (TARP). TARP implements security by distributing centrally issued secure IP/Medium Access Control (MAC) address mapping attestations through existing ARP messages. We detail TARP and its implementation within the Linux operating system. We also detail the integration of TARP with the Dynamic Host Configuration Protocol (DHCP) for dynamic ticket distribution. Our experimental analysis shows that TARP improves the costs of implementing ARP security by as much as two orders of magnitude over existing protocols. We conclude by exploring a range of operational issues associated with deploying and administering ARP security. DA - 2007/10// PY - 2007/10// DO - 10.1016/j.comnet.2007.05.007 VL - 51 IS - 15 SP - 4322-4337 J2 - Computer Networks LA - en OP - SN - 1389-1286 UR - http://dx.doi.org/10.1016/j.comnet.2007.05.007 DB - Crossref KW - network security KW - ARP security ER - TY - JOUR TI - Sampling streaming data with replacement AU - Park, Byung-Hoon AU - Ostrouchov, George AU - Samatova, Nagiza F. T2 - Computational Statistics & Data Analysis AB - Simple random sampling is a widely accepted basis for estimation from a population. When data come as a stream, the total population size continuously grows and only one pass through the data is possible. Reservoir sampling is a method of maintaining a fixed size random sample from streaming data. Reservoir sampling without replacement has been extensively studied and several algorithms with sub-linear time complexity exist. Although reservoir sampling with replacement is previously mentioned by some authors, it has been studied very little and only linear algorithms exist. A with-replacement reservoir sampling algorithm of sub-linear time complexity is introduced. A thorough complexity analysis of several approaches to the with-replacement reservoir sampling problem is also provided. DA - 2007/10// PY - 2007/10// DO - 10.1016/j.csda.2007.03.010 VL - 52 IS - 2 SP - 750-762 J2 - Computational Statistics & Data Analysis LA - en OP - SN - 0167-9473 UR - http://dx.doi.org/10.1016/j.csda.2007.03.010 DB - Crossref KW - data stream mining KW - random sampling with replacement KW - reservoir sampling ER - TY - CHAP TI - Measuring Bandwidth Signatures of Network Paths AU - Neginhal, Mradula AU - Harfoush, Khaled AU - Perros, Harry T2 - NETWORKING 2007. Ad Hoc and Sensor Networks, Wireless Networks, Next Generation Internet A2 - Akyildiz, I.F. A2 - Sivakumar, R. A2 - Ekici, E. A2 - Oliveira, J.C. A2 - McNair, J. T3 - Lecture Notes in Computer Science AB - In this paper, we propose a practical and efficient technique, Forecaster, to estimate (1) the end-to-end available bandwidth, and (2) the speed of the most congested (tight) link along an Internet path. Forecaster is practical since it does not assume any a priori knowledge about the measured path, does not make any simplifying assumptions about the nature of cross-traffic, does not assume the ability to capture accurate packet dispersions or packet queueing delays, and does not try to preserve inter-packet spacing along path segments. It merely relies on a simple binary test to estimate whether each probe packet has queued in the network or not. Forecaster is efficient as it only requires two streams of probe packets that are sent end-to-end at rates that are much lower than the available bandwidth of the investigated path, thus avoiding path saturation. Theoretical analysis and experimental results validate the efficacy of the proposed technique. PY - 2007/// DO - 10.1007/978-3-540-72606-7_92 SP - 1072–1083 OP - PB - Springer SN - 9783540726050 9783540726067 SV - 4479 UR - http://dx.doi.org/10.1007/978-3-540-72606-7_92 DB - Crossref ER - TY - CHAP TI - Early Prediction of Student Frustration AU - McQuiggan, Scott W. AU - Lee, Sunyoung AU - Lester, James C. T2 - Affective Computing and Intelligent Interaction AB - Affective reasoning has been the subject of increasing attention in recent years. Because negative affective states such as frustration and anxiety can impede progress toward learning goals, intelligent tutoring systems should be able to detect when a student is anxious or frustrated. Being able to detect negative affective states early, i.e., before they lead students to abandon learning tasks, could permit intelligent tutoring systems sufficient time to adequately prepare for, plan, and enact affective tutorial support strategies. A first step toward this objective is to develop predictive models of student frustration. This paper describes an inductive approach to student frustration detection and reports on an experiment whose results suggest that frustration models can make predictions early and accurately. PY - 2007/9/1/ DO - 10.1007/978-3-540-74889-2_61 SP - 698-709 OP - PB - Springer Berlin Heidelberg SN - 9783540748885 9783540748892 UR - http://dx.doi.org/10.1007/978-3-540-74889-2_61 DB - Crossref ER - TY - CHAP TI - Inducing User Affect Recognition Models for Task-Oriented Environments AU - Lee, Sunyoung AU - McQuiggan, Scott W. AU - Lester, James C. T2 - User Modeling 2007 AB - Accurately recognizing users’ affective states could contribute to more productive and enjoyable interactions, particularly for task-oriented learning environments. In addition to using physiological data, affect recognition models can leverage knowledge of task structure and user goals to effectively reason about users’ affective states. In this paper we present an inductive approach to recognizing users’ affective states based on appraisal theory, a motivational-affect account of cognition in which individuals’ emotions are generated in response to their assessment of how their actions and events in the environment relate to their goals. Rather than manually creating the models, the models are learned from training sessions in which (1) physiological data, (2) information about users’ goals and actions, and (3) environmental information are recorded from traces produced by users performing a range of tasks in a virtual environment. An empirical evaluation with a task-oriented learning environment testbed suggests that an inductive approach can learn accurate models and that appraisal-based models exploiting knowledge of task structure and user goals can outperform purely physiologically-based models. PY - 2007/8/27/ DO - 10.1007/978-3-540-73078-1_49 SP - 380-384 OP - PB - Springer Berlin Heidelberg SN - 9783540730774 9783540730781 UR - http://dx.doi.org/10.1007/978-3-540-73078-1_49 DB - Crossref ER - TY - CHAP TI - Clustering for Hierarchical Traffic Grooming in Large Scale Mesh WDM Networks AU - Chen, Bensong AU - Dutta, Rudra AU - Rouskas, George N. T2 - Optical Network Design and Modeling AB - We present a clustering algorithm for hierarchical traffic grooming in large WDM networks. In hierarchical grooming, the network is decomposed into clusters, and one hub node in each cluster is responsible for grooming traffic from and to the cluster. Hierarchical grooming scales to large network sizes and facilitates the control and management of traffic and network resources. Yet determining the size and composition of clusters so as to yield good grooming solutions is a challenging task. We identify the grooming-specific factors affecting the selection of clusters, and we develop a parameterized clustering algorithm that can achieve a desired tradeoff among various goals. PY - 2007/7/20/ DO - 10.1007/978-3-540-72731-6_28 SP - 249-258 OP - PB - Springer Berlin Heidelberg SN - 9783540727293 UR - http://dx.doi.org/10.1007/978-3-540-72731-6_28 DB - Crossref ER - TY - JOUR TI - Component-based end-user database design for ecologists AU - Cushing, Judith Bayard AU - Nadkarni, Nalini AU - Finch, Michael AU - Fiala, Anne AU - Murphy-Hill, Emerson AU - Delcambre, Lois AU - Maier, David T2 - Journal of Intelligent Information Systems DA - 2007/2/27/ PY - 2007/2/27/ DO - 10.1007/S10844-006-0028-6 VL - 29 IS - 1 SP - 7-24 J2 - J Intell Inf Syst LA - en OP - SN - 0925-9902 1573-7675 UR - http://dx.doi.org/10.1007/S10844-006-0028-6 DB - Crossref KW - ecosystem informatics KW - end-user programming KW - domain-specific data structures KW - spatial databases KW - scientific visualization ER - TY - CONF TI - SPARQ2L AB - Many applications in analytical domains often have the need to connect the dots i.e., query about the structure of data. In bioinformatics for example, it is typical to want to query about interactions between proteins. The aim of such queries is to extract relationships between entities i.e. paths from a data graph. Often, such queries will specify certain constraints that qualifying results must satisfy e.g. paths involving a set of mandatory nodes. Unfortunately, most present day Semantic Web query languages including the current draft of the anticipated recommendation SPARQL, lack the ability to express queries about arbitrary path structures in data. In addition, many systems that support some limited form of path queries rely on main memory graph algorithms limiting their applicability to very large scale graphs. In this paper, we present an approach for supporting Path Extraction queries. Our proposal comprises (i) a query language SPARQ2L which extends SPARQL with path variables and path variable constraint expressions, and (ii) a novel query evaluation framework based on efficient algebraic techniques for solving path problems which allows for path queries to be efficiently evaluated on disk resident RDF graphs. The effectiveness of our proposal is demonstrated by a performance evaluation of our approach on both real world based and synthetic dataset. C2 - 2007/// C3 - Proceedings of the 16th international conference on World Wide Web - WWW '07 DA - 2007/// DO - 10.1145/1242572.1242680 UR - http://dx.doi.org/10.1145/1242572.1242680 ER - TY - CONF TI - Estimating the cardinality of RDF graph patterns AB - Most RDF query languages allow for graph structure search through a conjunction of triples which is typically processed using join operations. A key factor in optimizing joins is determining the join order which depends on the expected cardinality of intermediate results. This work proposes a pattern-based summarization framework for estimating the cardinality of RDF graph patterns. We present experiments on real world and synthetic datasets which confirm the feasibility of our approach. C2 - 2007/// C3 - Proceedings of the 16th international conference on World Wide Web - WWW '07 DA - 2007/// DO - 10.1145/1242572.1242782 UR - http://dx.doi.org/10.1145/1242572.1242782 ER - TY - CONF TI - High-contrast algorithm behavior AU - Stallmann, Matthias F. AU - Brglez, Franc T2 - the 2007 workshop AB - After extensive experiments with two algorithms, CPLEX and our implementation of all-integer dual simplex, we observed extreme differences between the two on a set of design automation benchmarks. In many cases one of the two would find an optimal solution within seconds while the other timed out at one hour. C2 - 2007/// C3 - Proceedings of the 2007 workshop on Experimental computer science - ExpCS '07 DA - 2007/// DO - 10.1145/1281700.1281712 PB - ACM Press SN - 9781595937513 UR - http://dx.doi.org/10.1145/1281700.1281712 DB - Crossref ER - TY - CHAP TI - ChipViz: Visualizing Memory Chip Test Data AU - Sawant, Amit P. AU - Raina, Ravi AU - Healey, Christopher G. T2 - Advances in Visual Computing AB - This paper presents a technique that allows test engineers to visually analyze and explore within memory chip test data. We represent the test results from a generation of chips along a traditional 2D grid and a spiral. We also show correspondences in the test results across multiple generations of memory chips. We use simple geometric “glyphs” that vary their spatial placement, color, and texture properties to represent the critical attribute values of a test. When shown together, the glyphs form visual patterns that support exploration, facilitate discovery of data characteristics, relationships, and highlight trends and exceptions in the test data that are often difficult to identify with existing statistical tools. PY - 2007/// DO - 10.1007/978-3-540-76856-2_70 SP - 711-720 OP - PB - Springer Berlin Heidelberg SN - 9783540768555 9783540768562 UR - http://dx.doi.org/10.1007/978-3-540-76856-2_70 DB - Crossref ER - TY - JOUR TI - Simulation of Fusion Plasmas: Current Status and Future Direction AU - Batchelor, D A AU - Beck, M AU - Becoulet, A AU - Budny, R V AU - Chang, C S AU - Diamond, P H AU - Dong, J Q AU - Fu, G Y AU - Fukuyama, A AU - Hahm, T S AU - Keyes, D E AU - Kishimoto, Y AU - Klasky, S AU - Lao, L L AU - Li, K AU - Lin, Z AU - Ludaescher, B AU - Manickam, J AU - Nakajima, N AU - Ozeki, T AU - Podhorszki, N AU - Tang, W M AU - Vouk, M A AU - Waltz, R E AU - Wang, S J AU - Wilson, H R AU - Xu, X Q AU - Yagi, M AU - Zonca, F T2 - Plasma Science and Technology AB - I. Introduction (Z. Lin, G. Y. Fu, J. Q. Dong) II. Role of theory and simulation in fusion sciences 1. The Impact of theory and simulation on tokomak experiments (H. R. Wilson, T.S. Hahm and F. Zonca) 2. Tokomak Transport Physics for the Era of ITER: Issues for Simulations (P.H. Diamond and T.S. Hahm) III. Status of fusion simulation and modeling 1. Nonlinear Governing Equations for Plasma Simulations (T. S. Hahm) 2. Equilibrium and stability (L.L. Lao, J. Manickam) 3. Transport modeling (R.E. Waltz) 4. Nonlinear MHD (G.Y. Fu) 5. Turbulence (Z. Lin and R.E. Waltz) 6. RF heating and current drive (D.A. Batchelor) 7. Edge physics Simulations (X.Q. Xu and C.S. Chang) 8. Energetic particle physics (F. Zonca, G.Y. Fu and S.J. Wang) 9. Time-dependent Integrated Modeling (R.V. Budny) 10. Validation and verification (J. Manickam) IV. Major initiatives on fusion simulation 1. US Scientific Discovery through Advanced Computing (SciDAC) Program & Fusion Energy Science (W. Tang) 2. EU Integrated Tokamak Modelling (ITM) Task Force (A. Becoulet) 3. Fusion Simulations Activities in Japan (A. Fukuyama, N. Nakajima, Y. Kishimoto, T. Ozeki, and M. Yagi) V. Cross-disciplinary research in fusion simulation 1. Applied mathematics: Models, Discretizations, and Solvers (D.E. Keyes) 2. Computational Science (K. Li) 3. Scientific Data and Workflow Management (S. Klasky, M. Beck, B. Ludaescher, N. Podhorszki, M.A. Vouk) 4. Collaborative tools (J. Manickam) DA - 2007/6// PY - 2007/6// DO - 10.1088/1009-0630/9/3/13 VL - 9 IS - 3 SP - 312-387 J2 - Plasma Sci. Technol. OP - SN - 1009-0630 UR - http://dx.doi.org/10.1088/1009-0630/9/3/13 DB - Crossref ER - TY - CHAP TI - Automation of Network-Based Scientific Workflows AU - Vouk, M. A. AU - Altintas, I. AU - Barreto, R. AU - Blondin, J. AU - Cheng, Z. AU - Critchlow, T. AU - Khan, A. AU - Klasky, S. AU - Ligon, J. AU - Ludaescher, B. AU - Mouallem, P. A. AU - Parker, S. AU - Podhorszki, N. AU - Shoshani, A. AU - Silva, C. T2 - IFIP The International Federation for Information Processing AB - Comprehensive, end-to-end, data and workflow management solutions are needed to handle the increasing complexity of processes and data volumes associated with modern distributed scientific problem solving, such as ultrascale simulations and high-throughput experiments. The key to the solution is an integrated network-based framework that is functional, dependable, faulttolerant, and supports data and process provenance. Such a framework needs to make development and use of application workflows dramatically easier so that scientists’ efforts can shift away from data management and utility software development to scientific research and discovery. An integrated view of these activities is provided by the notion of scientific workflows - a series of structured activities and computations that arise in scientific problem-solving. An information technology framework that supports scientific workflows is the Ptolemy II based environment called Kepler. This paper discusses the issues associated with practical automation of scientific processes and workflows and illustrates this with workflows developed using the Kepler framework and tools. PY - 2007/11/16/ DO - 10.1007/978-0-387-73659-4_3 SP - 35-61 OP - PB - Springer US SN - 9780387736587 UR - http://dx.doi.org/10.1007/978-0-387-73659-4_3 DB - Crossref ER - TY - BOOK TI - Evaluating a simulated student using real students data for training and testing AU - Matsuda, N. AU - Cohen, W.W. AU - Sewall, J. AU - Lacerda, G. AU - Koedinger, K.R. DA - 2007/// PY - 2007/// VL - 4511 LNCS SE - 107-116 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-37249054311&partnerID=MN8TOARS ER - TY - CHAP TI - Size Competitive Meshing Without Large Angles AU - Miller, Gary L. AU - Phillips, Todd AU - Sheehy, Donald T2 - Automata, Languages and Programming AB - We present a new meshing algorithm for the plane, Overlay Stitch Meshing (OSM), accepting as input an arbitrary Planar Straight Line Graph and producing a triangulation with all angles smaller than 170°. The output triangulation has competitive size with any optimal size mesh having equally bounded largest angle. The competitive ratio is O(log(L/s)) where L and s are respectively the largest and smallest features in the input. OSM runs in O(n log(L/s) + m) time/work where n is the input size and m is the output size. The algorithm first uses Sparse Voronoi Refinement to compute a quality overlay mesh of the input points alone. This triangulation is then combined with the input edges to give the final mesh. PY - 2007/8/25/ DO - 10.1007/978-3-540-73420-8_57 SP - 655-666 OP - PB - Springer Berlin Heidelberg SN - 9783540734192 9783540734208 UR - http://dx.doi.org/10.1007/978-3-540-73420-8_57 DB - Crossref ER - TY - CONF TI - Representing and reasoning about commitments in business processes AU - Desai, N. AU - Chopra, A.K. AU - Singh, M.P. C2 - 2007/// C3 - Proceedings of the National Conference on Artificial Intelligence DA - 2007/// VL - 2 SP - 1328-1333 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36349027545&partnerID=MN8TOARS ER - TY - CONF TI - Toward verification of commitment protocols and their compositions AU - Desai, N. AU - Cheng, Z. AU - Chopra, A.K. AU - Singh, M.P. AB - Commitment protocols have been proposed as a basis for modeling and enacting interactions among agents, such as those needed to carry out business processes. A central idea is that protocols would be developed and shared via libraries, and refined and composed to produce protocols that serve specific needs. Success in this program, therefore, presupposes that individual protocols and their compositions can be formally verified with respect to the properties of interest. This paper outlines an approach for verifying the correctness of commitment protocols and their compositions that exploits the well-known software engineering technique of model checking. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329165 SP - 144-146 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-60349102464&partnerID=MN8TOARS ER - TY - JOUR TI - Governance of cross-organizational service agreements: A policy-based approach T2 - IEEE INTERNATIONAL CONFERENCE ON SERVICES COMPUTING, PROCEEDINGS DA - 2007/// PY - 2007/// UR - https://publons.com/publon/21294458/ ER - TY - JOUR TI - Formalizing Communication Protocols for Multiagent Systems T2 - 20TH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE DA - 2007/// PY - 2007/// UR - https://publons.com/publon/21294460/ ER - TY - JOUR TI - Formal Trust Model for Multiagent Systems T2 - 20TH INTERNATIONAL JOINT CONFERENCE ON ARTIFICIAL INTELLIGENCE DA - 2007/// PY - 2007/// UR - https://publons.com/publon/21294461/ ER - TY - CONF TI - Governance of cross-organizational service agreements: A policy-based approach AU - Udupi, Y.B. AU - Singh, M.P. AB - Many real-life organizations are hierarchies of largely autonomous, heterogeneous members (individuals or other organizations), often exhibiting rich policies. We restrict our attention to organizations that monitor their environment, collate events, determine compliance of their behaviors with their policies, and potentially act in anticipation of events to ensure the satisfaction of their policies. This paper models cross-organizational service agreements as resulting in the formation of organizations. This paper emphasizes the importance of proactive policy-based governance in organizations (modeled as multiagent systems) and provides a novel architecture supporting policy monitoring, governance, and enactment. This paper provides an initial formalization and discusses the compliance and completeness of behaviors produced from specified policies. To demonstrate the practical utility of this approach, it is implemented using an existing policy engine and messaging middleware. C2 - 2007/// C3 - Proceedings - 2007 IEEE International Conference on Services Computing, SCC 2007 DA - 2007/// DO - 10.1109/SCC.2007.63 SP - 36-43 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35248815169&partnerID=MN8TOARS ER - TY - CONF TI - Engineering foreign exchange processes via commitment protocols AU - Desai, N. AU - Chopra, A.K. AU - Arrott, M. AU - Spechte, B. AU - Singh, M.P. AB - Foreign exchange (FX) markets see a transaction volume of over $2 trillion per day. A number of standard ways of conducting business have been developed in the FX industry. However, current FX specifications are informal and their business semantics unclear. The resulting implementations tend to be complex and compliance with the standards unverifiable. This results in potential loss of value due to incompatible business processes and possible trades not consummated. This paper validates a formal, protocol-based approach by specifying foreign exchange processes as standardized by the TWIST consortium. The proposed approach formalizes a small, core set of foreign exchange interaction protocols on which the desired processes can be based. The core protocols can be composed to yield a large variety of possible processes. Each protocol is rigorously defined in terms of the commitments undertaken and manipulated by the parties involved. By contrast, traditional approaches as used in the current TWIST specification lead to redundancy in specification and difficulty in understanding the import of the interactions involved. In addition, our approach discovered interesting business scenarios that traditional approaches would have missed. C2 - 2007/// C3 - Proceedings - 2007 IEEE International Conference on Services Computing, SCC 2007 DA - 2007/// DO - 10.1109/SCC.2007.58 SP - 514-521 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-35248848926&partnerID=MN8TOARS ER - TY - JOUR TI - Logic-Based Agent Verification AU - Fisher, M. AU - Singh, M. AU - Spears, D. AU - Wooldridge, M. T2 - Journal of Applied Logic DA - 2007/// PY - 2007/// DO - 10.1016/j.jal.2005.12.012 VL - 5 IS - 2 SP - 193-195 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-34247135747&partnerID=MN8TOARS ER - TY - CONF TI - InterPol: A policy framework for managing trust and privacy in referral networks AU - Udupi, Y.B. AU - Singh, M.P. AB - Referral networks are a kind of P2P system consisting of autonomous agents who seek, provide services, or refer other service providers. Key applications include service discovery and selection, and knowledge sharing. This use of referrals is inspired by human interactions, where referrals are a key basis for judging the trustworthiness of a given service. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329332 SP - 1095-1097 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-60349089685&partnerID=MN8TOARS ER - TY - CONF TI - An event-driven approach for agent-based business process enactment AU - Chakravarty, P. AU - Singh, M.P. AB - Agents enacting business processes in large open environments need to adaptively accommodate exceptions. Work on multiagent approaches can flexibly model business processes. This paper proposes an event-driven architecture that enriches such models with events resulting in a more robust and proactive system. Specifically, we place this architecture in a business process framework based on protocols and policies, where agents' behaviors are specified via rules. The contributions of this paper include (1) an event-driven architecture, (2) a specification language that combines event logic with rules and (3) a methodology to incorporate events into a process (such as for fine-grained monitoring), (4) a way to manage subscriptions to simple events efficiently. This approach is applied on a well-known business scenario. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329383 SP - 1269-1271 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-60349117905&partnerID=MN8TOARS ER - TY - CONF TI - A modular action description language for protocol composition AU - Desai, N. AU - Singh, M.P. C2 - 2007/// C3 - Proceedings of the National Conference on Artificial Intelligence DA - 2007/// VL - 2 SP - 962-967 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36349036553&partnerID=MN8TOARS ER - TY - CONF TI - Enacting protocols by commitment concession AU - Yolum, P. AU - Singh, M.P. AB - Commitment protocols formalize interactions among autonomous, heterogeneous agents, leaving the agents' local policies unspecified. This paper studies the problem of agents enacting commitment protocols, which inherently requires that their policies cohere with the given protocols. Specifically, in many important settings, if agents incautiously create and discharge commitments, they can expose themselves to certain risk; conversely, if the agents are (excessively) cautious, a protocol enactment may deadlock. This paper adopts the well-known idea of monotonic concession, but specializes and enhances it with the particular features of commitments. Specifically, this paper formulates inference rules for commitment concession that respect the nature of commitments. Next, it shows how commitments can be systematically revised as the agents incrementally engage each other in enacting their protocol. This paper demonstrates how such rules can be applied in practice, and identifies conditions under which progress and termination of protocol enactment can be guaranteed. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329158 SP - 116-123 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-45449096030&partnerID=MN8TOARS ER - TY - CONF TI - Dynamics of contracts-based organizations: A formal approach based on institutions AU - Udupi, Y.B. AU - Singh, M.P. AB - An organization comprises a group of collaborating agents (individual agents or nested organizations) that exhibit complex behaviors. Of particular interest are dynamic organizations that form and dissolve as their members' needs change. Such organizations are important in many applications, including scientific and business computing. Contracts among autonomous agents have long been used to facilitate their collaboration. This paper provides a contracts-based approach for managing organizations. The proposed approach places organizations within institutions, themselves modeled as specialized organizations. Commitments form the basis of contracts and this paper establishes some important dynamic aspects by providing a commitment life cycle analysis. This approach has been applied in a prototype tool to manage organizations. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329149 SP - 82-84 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-60349099664&partnerID=MN8TOARS ER - TY - CONF TI - Choice and interoperation in protocol enactment AU - Chopra, A.K. AU - Singh, M.P. AB - Protocols describe interactions among agents and thus underlie the engineering of multiagent systems. However, protocols are enacted by agents in physical systems. In particular, considerations of communication models and how distributed agents are able to make compatible choices would greatly affect whether a protocol may in fact be enacted successfully. The objective of this paper is to study the conceptual underpinnings of protocol enactment in multiagent systems. It seeks to characterize the operationalization of agents so as to determine whether and when agents may be interoperable. C2 - 2007/// C3 - Proceedings of the International Conference on Autonomous Agents DA - 2007/// DO - 10.1145/1329125.1329161 SP - 132-134 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-60349125584&partnerID=MN8TOARS ER - TY - CONF TI - Interest-matching comparisons using CP-nets AU - Wicker, A.W. AU - Doyle, J. C2 - 2007/// C3 - Proceedings of the National Conference on Artificial Intelligence DA - 2007/// VL - 2 SP - 1914-1915 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36348991910&partnerID=MN8TOARS ER - TY - JOUR TI - AAAI-07 workshop reports AU - Anand, S.S. AU - Bahls, D. AU - Burghart, C.R. AU - Burstein, M. AU - Chen, H. AU - Collins, J. AU - Dietterich, T. AU - Doyle, J. AU - Drummond, C. AU - Elazmeh, W. AU - Geib, C. AU - Goldsmith, J. AU - Guesgen, H.W. AU - Hendler, J. AU - Jannach, D. AU - Japkowicz, N. AU - Junker, U. AU - Kaminka, G.A. AU - Kobsa, A. AU - Lang, J. AU - Leake, D.B. AU - Lewis, L. AU - Ligozat, G. AU - Macskassy, S. AU - McDermott, D. AU - Metzler, T. AU - Mobasher, B. AU - Nambiar, U. AU - Nie, Z. AU - Orsvarn, K. AU - O’Sullivan, B. AU - Pynadath, D. AU - Renz, J. AU - Rodriguez, R.V. AU - Roth-Berghofer, T. AU - Schulz, S. AU - Studer, R. AU - Wang, Y. AU - Wellman, M. T2 - AI Magazine DA - 2007/// PY - 2007/// VL - 28 IS - 4 SP - 119-128 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-39049150323&partnerID=MN8TOARS ER - TY - CONF TI - AAAI Workshop - Technical Report: Preface AU - Doyle, J. AU - Goldsmith, J. AU - Junker, U. AU - Lang, J. C2 - 2007/// C3 - AAAI Workshop - Technical Report DA - 2007/// VL - WS-07-10 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-51849090045&partnerID=MN8TOARS ER - TY - RPRT TI - View and index selection for query-performance improvement: Algorithms, heuristics and complexity AU - Kormilitsin, Maxim AU - Chirkova, Rada Y AU - Fathi, Yahya AU - Stallmann, Matthias F A3 - North Carolina State University. Dept. of Computer Science DA - 2007/// PY - 2007/// PB - North Carolina State University. Dept. of Computer Science ER - TY - CONF TI - Proofchecker: an accessible environment for automata theory correctness proofs AU - Stallmann, Matthias F AU - Balik, Suzanne P AU - Rodman, Robert D AU - Bahram, Sina AU - Grace, Michael C AU - High, Susan D T2 - ACM C2 - 2007/// C3 - ACM SIGCSE Bulletin DA - 2007/// VL - 39 SP - 48-52 M1 - 3 ER - TY - CONF TI - High-contrast algorithm behavior: observation, hypothesis, and experimental design AU - Stallmann, Matthias F AU - Brglez, Franc T2 - ACM C2 - 2007/// C3 - Proceedings of the 2007 workshop on Experimental computer science DA - 2007/// SP - 12 ER - TY - JOUR TI - A case for smaller class size with integrated lab for introductory computer science AU - Boyer, Kristy Elizabeth AU - Dwight, Rachael S AU - Miller, Carolyn S AU - Raubenheimer, C Dianne AU - Stallmann, Matthias F AU - Vouk, Mladen A T2 - ACM SIGCSE Bulletin DA - 2007/// PY - 2007/// VL - 39 IS - 1 SP - 341-345 ER - TY - JOUR TI - Irreducible polynomials and barker sequences AU - Borwein, Peter AU - Kaltofen, Erich AU - Mossinghoff, Michael J. T2 - ACM Communications in Computer Algebra AB - A Barker sequence is a finite sequence a o , ..., a n -1 , each term ±1, for which every sum Σ i a i a i +k with 0 < k < n is either 0, 1, or -- 1. It is widely conjectured that no Barker sequences of length n > 13 exist, and this conjecture has been verified for the case when n is odd. We show that in this case the problem can in fact be reduced to a question of irreducibility for a certain family of univariate polynomials: No Barker sequence of length 2 m + 1 exists if a particular integer polynomial of degree 4 m is irreducible over Q. A proof of irreducibility for this family would thus provide a short, alternative proof that long Barker sequences of odd length do not exist. However, we also prove that the polynomials in question are always reducible modulo p , for every prime p . DA - 2007/12/1/ PY - 2007/12/1/ DO - 10.1145/1358183.1358185 VL - 41 IS - 4 SP - 118 J2 - ACM Commun. Comput. Algebra LA - en OP - SN - 1932-2240 UR - http://dx.doi.org/10.1145/1358183.1358185 DB - Crossref ER - TY - CHAP TI - Structured Low Rank Approximation of a Sylvester Matrix AU - Kaltofen, Erich AU - Yang, Zhengfeng AU - Zhi, Lihong T2 - Trends in Mathematics AB - The task of determining the approximate greatest common divisor (GCD) of univariate polynomials with inexact coefficients can be formulated as computing for a given Sylvester matrix a new Sylvester matrix of lower rank whose entries are near the corresponding entries of that input matrix. We solve the approximate GCD problem by a new method based on structured total least norm (STLN) algorithms, in our case for matrices with Sylvester structure. We present iterative algorithms that compute an approximate GCD and that can certify an approximate ∈-GCD when a tolerance ∈ is given on input. Each single iteration is carried out with a number of floating point operations that is of cubic order in the input degrees. We also demonstrate the practical performance of our algorithms on a diverse set of univariate pairs of polynomials. PY - 2007/6/24/ DO - 10.1007/978-3-7643-7984-1_5 SP - 69-83 OP - PB - Birkhäuser Basel SN - 9783764379834 UR - http://dx.doi.org/10.1007/978-3-7643-7984-1_5 DB - Crossref KW - Sylvester matrix KW - approximate greatest common divisor KW - structured total least norm KW - hybrid symbolic/numeric algorithm ER - TY - CONF TI - Using independent-study projects in your research and teaching program AU - Gehringer, Edward F. T2 - 2007 ASEE Annual Conference and Exposition C2 - 2007/// C3 - Proceedings of the 2007 ASEE Annual Conference and Exposition CY - Honolulu, HI DA - 2007/// PY - 2007/6/24/ PB - American Society for Engineering Education ER - TY - CONF TI - Active and collaborative learning strategies for teaching computing AU - Gehringer, Edward F. T2 - 2007 ASEE Annual Conference and Exposition C2 - 2007/// C3 - Proceedings of the 2007 ASEE Annual Conference and Exposition CY - Honolulu, HI DA - 2007/// PY - 2007/6/24/ PB - American Society for Engineering Education ER - TY - JOUR TI - Reusable learning objects through peer review: The Expertiza approach AU - Gehringer, Edward F. AU - Ehresman, Luke M. AU - Conger, Susan G. AU - Wagle, Prasad A. T2 - Innovate—Journal of Online Education DA - 2007/8// PY - 2007/8// VL - 3 IS - 6 ER - TY - CONF TI - Animations of important concepts in parallel computer architecture AU - Gambhir, Mohit AU - Gehringer, Edward F. AU - Solihin, Yan T2 - the 2007 workshop AB - Resources for teaching parallel computer architecture--specifically, cache coherence and memory consistency--are increasing in importance. Through instructor-created templates, followed by peer-reviewed student work, we have produced a set of animations that can be used for classroom presentation or self-study. These animations cover bus-based coherence protocols, such as MSI, MOESI, and Dragon; and network-based protocols, such as the full bit-vector scheme and a simplified version of SCI. Some animations illustrate the operation of a particular protocol, while others compare protocols against each other. Other animations cover memory-consistency models, such as sequential consistency, processor consistency, weak ordering, and release consistency. C2 - 2007/// C3 - Proceedings of the 2007 workshop on Computer architecture education - WCAE '07 DA - 2007/// DO - 10.1145/1275633.1275638 PB - ACM Press SN - 9781595937971 UR - http://dx.doi.org/10.1145/1275633.1275638 DB - Crossref ER - TY - CONF TI - Unc-ch at duc 2007: Query expansion, lexical simplification and sentence selection strategies for multi-document summarization AU - Blake, Catherine AU - Kampov, Julia AU - Orphanides, Andreas K AU - West, David AU - Lown, Cory C2 - 2007/// C3 - Proceedings of Document Understanding Conference (DUC) Workshop DA - 2007/// ER - TY - JOUR TI - AN EXPERIMENTAL STUDY ON SECURITY PROTOCOLS IN WLANS AU - Agarwal, Avesh Kumar AU - Wang, Wenye T2 - WIRELESS NETWORK SECURITY DA - 2007/// PY - 2007/// DO - 10.1007/978-0-387-33112-6_12 SP - 295-322 SN - 1860-4862 ER - TY - CONF TI - Formalizing communication protocols for multiagent systems AU - Singh, M.P. C2 - 2007/// C3 - IJCAI International Joint Conference on Artificial Intelligence DA - 2007/// SP - 1519-1524 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-75649138061&partnerID=MN8TOARS ER - TY - CONF TI - Formal trust model for multiagent systems AU - Wang, Y. AU - Singh, M.P. C2 - 2007/// C3 - IJCAI International Joint Conference on Artificial Intelligence DA - 2007/// SP - 1551-1556 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84880909594&partnerID=MN8TOARS ER - TY - JOUR TI - Dense-timed petri nets: Checking zenoness, token liveness and boundedness AU - Abdulla, P. A. AU - Mahata, P. AU - Mayr, R. T2 - Logical Methods in Computer Science DA - 2007/// PY - 2007/// VL - 3 IS - 1 ER - TY - JOUR TI - Decisive Markov chains AU - Abdulla, P. A. AU - Ben Henda, N. AU - Mayr, R. T2 - Logical Methods in Computer Science DA - 2007/// PY - 2007/// VL - 3 IS - 4 ER - TY - CONF TI - Comparisons of SiC MOSFET and Si IGBT based motor drive systems AU - Zhao, T. F. AU - Wang, J. AU - Huang, A. Q. AU - Agarwal, A. AB - With the rapid development of silicon carbide (SiC) material quality, SiC power devices are gaining tremendous attentions in power electronics. In this paper, a SiC device based motor drive system is performed to provide a quantitative estimate of the system improvement. Two 60 kW motor drive systems based on SiC MOSFET/Schottky diode and Si IGBTs are designed. The power losses of the two inverters with sinusoidal pulse width modulation (SPWM) control are calculated analytically. By comparing the efficiencies, sizes and temperatures of the two designed systems, SiC device shows the superior advantages of smaller loss, better efficiency and smaller size in the same motor drive application. C2 - 2007/// C3 - Conference record of the 2007 IEEE Industry Applications Conference forty-second IAS annual meeting DA - 2007/// DO - 10.1109/07ias.2007.51 SP - 331-335 PB - New York: IEEE SN - 9781424412600 ER - TY - JOUR TI - Efficient software implementation of embedded communication protocol controllers using asynchronous software thread integration with time- and space-efficient procedure calls AU - Kumar, Nagendra J. AU - Asokan, Vasanth AU - Shivshankar, Siddhartha AU - Dean, Alexander G. T2 - ACM TRANSACTIONS ON EMBEDDED COMPUTING SYSTEMS AB - The overhead of context switching limits efficient scheduling of multiple concurrent threads on a uniprocessor when real-time requirements exist. A software-implemented protocol controller may be crippled by this problem. The available idle time may be too short to recover through context switching, so only the primary thread can execute during message activity, slowing the secondary threads and potentially missing deadlines. Asynchronous software thread integration (ASTI) uses coroutine calls and integration, letting threads make independent progress efficiently, and reducing the needed context switches. We demonstrate the methods with a software implementation of an automotive communication protocol (J1850) and several secondary threads. DA - 2007/2// PY - 2007/2// DO - 10.1145/1210268.1210270 VL - 6 IS - 1 SP - SN - 1558-3465 KW - algorithms KW - design KW - experimentation KW - asynchronous software thread integration KW - hardware to software migration KW - fine-grain concurrency KW - software-implemented communication protocol controllers KW - J1850 ER - TY - PAT TI - Methods and systems for rate-based flow control between a sender and a receiver AU - Rhee, I C2 - 2007/// DA - 2007/// PY - 2007/// ER - TY - JOUR TI - Interleaved hop-by-hop authentication against false data injection attacks in sensor networks AU - Zhu, Sencun AU - Setia, Sanjeev AU - Jajodia, Sushil AU - Ning, Peng T2 - ACM TRANSACTIONS ON SENSOR NETWORKS AB - Sensor networks are often deployed in unattended environments, thus leaving these networks vulnerable to false data injection attacks in which an adversary injects false data into the network with the goal of deceiving the base station or depleting the resources of the relaying nodes. Standard authentication mechanisms cannot prevent this attack if the adversary has compromised one or a small number of sensor nodes. We present three interleaved hop-by-hop authentication schemes that guarantee that the base station can detect injected false data immediately when no more than t nodes are compromised, where t is a system design parameter. Moreover, these schemes enable an intermediate forwarding node to detect and discard false data packets as early as possible. Our performance analysis shows that our scheme is efficient with respect to the security it provides, and it also allows a tradeoff between security and performance. A prototype implementation of our scheme indicates that our scheme is practical and can be deployed on the current generation of sensor nodes. DA - 2007/8// PY - 2007/8// DO - 10.1145/1267060.1267062 VL - 3 IS - 3 SP - SN - 1550-4867 KW - security KW - algorithm KW - design KW - authentication KW - filtering false data KW - interleaved hop-by-hop KW - sensor networks ER - TY - PAT TI - Gallium nitride material devices and methods of forming the same AU - Weeks, T. W. AU - Linthicum, K. J. C2 - 2007/// DA - 2007/// PY - 2007/// ER - TY - JOUR TI - A novel optimization approach for minimum cost design of trusses AU - Kripakaran, Prakash AU - Gupta, Abhinav AU - Baugh, John W., Jr. T2 - COMPUTERS & STRUCTURES AB - This paper describes new optimization strategies that offer significant improvements in performance over existing methods for bridge-truss design. In this study, a real-world cost function that consists of costs on the weight of the truss and the number of products in the design is considered. We propose a new sizing approach that involves two algorithms applied in sequence – (1) a novel approach to generate a “good” initial solution and (2) a local search that attempts to generate the optimal solution by starting with the final solution from the previous algorithm. A clustering technique, which identifies members that are likely to have the same product type, is used with cost functions that consider a cost on the number of products. The proposed approach gives solutions that are much lower in cost compared to those generated in a comprehensive study of the same problem using genetic algorithms (GA). Also, the number of evaluations needed to arrive at the optimal solution is an order of magnitude lower than that needed in GAs. Since existing optimization techniques use cost functions like those of minimum-weight truss problems to illustrate their performance, the proposed approach is also applied to the same examples in order to compare its relative performance. The proposed approach is shown to generate solutions of not only better quality but also much more efficiently. To highlight the use of this sizing approach in a broader optimization framework, a simple geometry optimization algorithm that uses the sizing approach is presented. This algorithm is also shown to provide solutions better than the existing results in literature. DA - 2007/12// PY - 2007/12// DO - 10.1016/j.compstruc.2007.04.006 VL - 85 IS - 23-24 SP - 1782-1794 SN - 1879-2243 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36049020582&partnerID=MN8TOARS KW - truss design KW - structural optimization KW - hybrid search KW - genetic algorithms KW - member grouping KW - discrete sizing optimization KW - cost minimization ER - TY - JOUR TI - The joint distribution of descent and major index over restricted sets of permutations AU - Corteel, Sylvie AU - Gessel, Ira M. AU - Savage, Carla D. AU - Wiif, Herbert S. T2 - ANNALS OF COMBINATORICS DA - 2007/// PY - 2007/// DO - 10.1007/s00026-007-0325-y VL - 11 IS - 3-4 SP - 375-386 SN - 0219-3094 KW - permutation enumeration KW - q-Eulerian polynomials KW - P-partitions ER - TY - JOUR TI - The ChoicePoint dilemma - How data brokers should handle the privacy of personal information AU - Otto, Paul N. AU - Anton, Annie I. AU - Baumer, David L. T2 - IEEE SECURITY & PRIVACY AB - Before 2005, data broker ChoicePoint suffered fraudulent access to its databases that exposed thousands of customers' personal information. We examine Choice-Point's data breach, explore what went wrong from the perspective of consumers, executives, policy, and IT systems, and offer recommendations for the future. DA - 2007/// PY - 2007/// DO - 10.1109/MSP.2007.126 VL - 5 IS - 5 SP - 15-23 SN - 1558-4046 ER - TY - JOUR TI - Optimal wavelength sharing policies in OBS networks subject to QoS constraints AU - Yang, Li AU - Rouskas, George N. T2 - IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS AB - We consider the general problem of optimizing the performance of OBS networks with multiple traffic classes subject to strict (absolute) QoS constraints in terms of the end-to-end burst loss rate of each guaranteed class of traffic. We employ Markov decision process (MDP) theory to obtain optimal wavelength sharing policies for two performance objectives, namely, maximization of weighted network throughput and minimization of the loss rate of best-effort traffic, while meeting the QoS guarantees. The randomized threshold policies we obtain are simple to implement and operate, and make effective use of statistical multiplexing. In particular, the threshold randomization feature enables the policies to allocate bandwidth at arbitrarily fine sub-wavelength granularity, hence making effective use of the available network capacity. DA - 2007/12// PY - 2007/12// DO - 10.1109/JSAC-OCN.2007.029707 VL - 25 IS - 9 SP - 40-49 SN - 1558-0008 KW - optical burst switching (OBS) networks KW - wavelength reservations KW - quality of service KW - Markov decision process KW - randomized threshold policies ER - TY - JOUR TI - Closure to "optimal design of redundant water distribution networks using a cluster of workstations" by Sujay V. Kumar, Troy A. Doby, John W. Baugh Jr., E. Downey Brill, and S. Ranji Ranjithan AU - Kumar, S. V. AU - Doby, T. A. AU - Baugh, J. W. AU - Brill, E. D. AU - Ranjithan, S. R. T2 - Journal of Water Resources Planning and Management DA - 2007/// PY - 2007/// DO - 10.1061/(asce)0733-9496(2007)133:6(580) VL - 133 IS - 6 SP - 580-581 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-36349011269&partnerID=MN8TOARS ER - TY - JOUR TI - Limitations of equation-based congestion control AU - Rhee, Injong AU - Xu, Lisong T2 - IEEE-ACM TRANSACTIONS ON NETWORKING AB - We study limitations of an equation-based congestion control protocol, called TCP-friendly rate control (TFRC). It examines how the three main factors that determine TFRC throughput, namely, the TCP-friendly equation, loss event rate estimation, and delay estimation, can influence the long-term throughput imbalance between TFRC and TCP. Especially, we show that different sending rates of competing flows cause these flows to experience different loss event rates. There are several fundamental reasons why TFRC and TCP flows have different average sending rates, from the first place. Earlier work shows that the convexity of the TCP-friendly equation used in TFRC causes the sending rate difference. We report two additional reasons in this paper: 1) the convexity of where is a loss event period and 2) different retransmission timeout period (RTO) estimations of TCP and TFRC. These factors can be the reasons for TCP and TFRC to experience initially different sending rates. But we find that the loss event rate difference due to the differing sending rates greatly amplifies the initial throughput difference; in some extreme cases, TFRC uses around 20 times more, or sometimes 10 times less, bandwidth than TCP. Despite these factors influencing the throughput difference, we also find that simple heuristics can greatly mitigate the problem. DA - 2007/8// PY - 2007/8// DO - 10.1109/TNET.2007.893883 VL - 15 IS - 4 SP - 852-865 SN - 1558-2566 KW - congestion control KW - equation-based rate control ER - TY - JOUR TI - Current update on drugs for game bird species AU - Needham, Martha L. AU - Webb, Alistair I. AU - Baynes, Ronald E. AU - Riviere, Jim E. AU - Craigmill, Arthur L. AU - Tell, Lisa A. T2 - JAVMA-JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION DA - 2007/11/15/ PY - 2007/11/15/ DO - 10.2460/javma.231.10.1506 VL - 231 IS - 10 SP - 1506-1508 SN - 1943-569X ER - TY - JOUR TI - An evolution of virtual reality training designs for children with autism and fetal alcohol spectrum disorders AU - Strickland, Dorothy C. AU - McAllister, David AU - Coles, Claire D. AU - Osborne, Susan T2 - TOPICS IN LANGUAGE DISORDERS AB - This article describes an evolution of training programs to use first-person interaction in virtual reality (VR) situations to teach safety skills to children with autism spectrum disorder (ASD) and fetal alcohol spectrum disorder (FASD). Multiple VR programs for children aged 2 to 9 were built and tested between 1992 and 2007. Based on these results, a learning design evolved that uses practice in virtual space with guidance and correction by an animated character, strategic limitations on allowed actions to force correct patterning, and customization of worlds and responses to simplify user controls. This article describes program evolution by comparing design details and results as variations in behavioral responses between disorders, differences in skill set complexity between different safety skills being taught, and improved technology required changes in the virtual training methodology. A series of research projects are summarized in which the VR programs proved effective for teaching children with ASD and FASD new skills in the virtual space and, where measured, most children generalized the actions to the real world. DA - 2007/// PY - 2007/// DO - 10.1097/01.TLD.0000285357.95426.72 VL - 27 IS - 3 SP - 226-241 SN - 1550-3259 ER - TY - JOUR TI - Model-based evaluation of expert cell phone menu interaction AU - Amant, R. S. AU - Horton, T. E. AU - Ritter, F. E. T2 - ACM Transactions on Computer-human Interaction DA - 2007/// PY - 2007/// VL - 14 IS - 1 ER - TY - JOUR TI - KERNELPOP, a spatially explicit population genetic simulation engine AU - Strand, Allan E. AU - Niehaus, James M. T2 - MOLECULAR ECOLOGY NOTES AB - Abstract Individual‐based, spatially explicit models provide a mechanism to understand distributions of individuals on the landscape; however, few models have been coupled with population genetics. The primary benefits of such a combination is to assess performance of population‐genetic estimators in realistic situations. kernelpop represents a flexible framework to implement almost any arbitrary population‐genetic and demographic model in a spatially explicit context using a variety of dispersal kernels. Estimates of type I error associated with genome scans in metapopulations are provided as an illustration of this software's utility. DA - 2007/11// PY - 2007/11// DO - 10.1111/j.1471-8286.2007.01832.x VL - 7 IS - 6 SP - 969-973 SN - 1471-8278 KW - dispersal KW - genome-scan KW - individual-based KW - neutral model ER - TY - JOUR TI - How much energy saving does topology control offer for wireless sensor networks? - A practical study AU - Warrier, Ajit AU - Park, Sangjoon AU - Min, Jeongki AU - Rhee, Injong T2 - COMPUTER COMMUNICATIONS AB - Topology control is an important feature for energy saving, and many topology control protocols have been proposed. Yet, little work has been done on quantitatively measuring practical performance gains that topology control achieves in a real sensor network. This is because many existing protocols either are too complex or make too impractical assumptions for a practical implementation and analysis. A rule of thumb or a practical upper bound on the energy saving gains achievable by topology control would assist engineers in estimating the overall energy budget of a real sensor system. This paper proposes a new topology control protocol simple enough to permit a straightforward stochastic analysis and also a real implementation in Mica2. This protocol is currently deployed in our testbed network of 42 Mica2 nodes. Our contribution is not on the novelty of this protocol but on a practical performance bound we can study using this protocol. The stochastic analysis reveals that topology control can achieve a power gain proportional to network density divided by a factor of eight to ten. Our experiment result from the real testbed tests confirms this finding. We also find a tradeoff in terms of throughput loss due to reduced density by topology control which amounts to about 50% throughput loss. These performance figures represent rough rules of thumb on energy efficiency achievable even by a very simple, unoptimized protocol. DA - 2007/10/15/ PY - 2007/10/15/ DO - 10.1016/j.comcom.2007.05.019 VL - 30 IS - 14-15 SP - 2867-2879 SN - 1873-703X KW - topology control KW - wireless sensor networks KW - cluster ER - TY - JOUR TI - Generalizing parametric timing analysis AU - Coffman, Joel AU - Healy, Christopher AU - Mueller, Frank AU - Whalley, David T2 - ACM SIGPLAN NOTICES AB - In the design of real-time and embedded systems, it is important to establish a bound on the worst-case execution time (WCET) of programs to assure via schedulability analysis that deadlines are not missed. Static WCET analysis is performed by a timing analysis tool. This paper describes novel improvements to such a tool, allowing parametric timing analysis to be performed. Parametric timing analyzers receive an upper bound on the number of loop iterations in terms of an expression which is used to create a parametric formula. This parametric formula is later evaluated to determine the WCET based on input values only known at runtime. Effecting a transformation from a numeric to a parametric timing analyzer requires two innovations: 1) a summation solver capable of summation non-constant expressions and 2) a polynomial data structure which can replace integers as the basis for all calculations. Both additions permit other methods of analysis (e.g. caching, pipeline, constraint) to occur simultaneously. Combining these techniques allows our tool to statically bound the WCET for a larger class of benchmarks. DA - 2007/7// PY - 2007/7// DO - 10.1145/1273444.1254795 VL - 42 IS - 7 SP - 152-154 SN - 1558-1160 KW - verification KW - reliability KW - worst-case execution time (WCET) analysis KW - parametric timing analysis ER - TY - JOUR TI - DVSleak: Combining leakage reduction and voltage scaling in feedback EDF scheduling AU - Zhu, Yifan AU - Mueller, Frank T2 - ACM SIGPLAN NOTICES AB - Recent trends in CMOS fabrication have the demand to conserve power of processors. While dynamic voltage scaling (DVS) is effective in reducing dynamic power, microprocessors produced in ever smaller fabrication processes are increasingly dominated bystatic power. For such processors, voltage/frequency pairs below acritical speed result in higher energy per cycle than entering a processor sleep mode. Yet, computational demand above this critical speed is best met by DVS techniques while still conserving power. We develop a novel combined leakage and DVS scheduling algorithm forreal-time systems, DVS leak, based on earliest-deadline-first scheduling (EDF). Our method trades off DVS with leakage, where the former slows down execution while the latter intelligently defers dispatching of jobs when sleeping is beneficial. We further capitalize on feedback knowledge about actual execution times to anticipate computational demands without sacrificing deadline guarantees. As such, we contribute a novel feedback delay policy for leakage awareness, which addresses structural limitations of prior approaches. Experiments show that this combined DVS/leakage algorithm results in an average of (a) 50% additional energy savings over a leakage-oblivious DVS algorithm, (b) 20% more energy savings over a more simplistic combination of DVS and sleep policies and (c) 8.5% or more over dynamic slack reclamation with procrastination. Particularly task sets with periods shorter than ten milliseconds profit from our approach with 15% energy savings over best prior schemes. This makes DVS leak the best combined DVS/leakage regulation approach for real-time systems that we know of. DA - 2007/7// PY - 2007/7// DO - 10.1145/1273444.1254772 VL - 42 IS - 7 SP - 31-40 SN - 1558-1160 KW - real-time systems KW - scheduling KW - dynamic voltage scaling KW - leakage KW - feedback control KW - algorithms KW - experimentation ER - TY - JOUR TI - A study of the variation of urban mixed layer heights AU - Simpson, Matthew AU - Raman, Sethu AU - Lundquist, Julie K. AU - Leach, Martin T2 - ATMOSPHERIC ENVIRONMENT AB - The AERMET model is used to estimate hourly mixing heights during the Joint URBAN (2003) experiment in Oklahoma City, Oklahoma. AERMET is a simple 2-D model that requires only routine meteorological observations and an early morning atmospheric sounding to estimate convective boundary layer (CBL) growth. Estimated mixing heights are compared with observed mixing heights measured during Joint URBAN 2003. Observed CBL heights are derived from profiler data using a peak signal-to-noise ratio method. The method of deriving mixing heights from profiler data is validated using daily atmospheric sounding data. Estimated mixing heights using AERMET show good agreement with observations on days of varying temperature and cloud cover. AERMET was able to estimate the rapid boundary layer growth observed in the late morning and early afternoon hours during highly convective conditions. CBL heights of over 3000 m are observed in sounding data during the late afternoon. Estimated CBL heights of over 3000 m during the late afternoon agreed well with observations from the sounding and profiler data. DA - 2007/10// PY - 2007/10// DO - 10.1016/j.atmosenv.2006.08.029 VL - 41 IS - 33 SP - 6923-6930 SN - 1352-2310 KW - AERMET KW - convective boundary layer KW - profiler KW - joint URBAN (2003) KW - signal-to-noise ratio ER - TY - JOUR TI - Weaving versus blending: a quantitative assessment of the information carrying capacities of two alternative methods for conveying multivariate data with color AU - Hagh-Shenas, Haleh AU - Kim, Sunghee AU - Interrante, Victoria T2 - IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS AB - In many applications, it is important to understand the individual values of, and relationships between, multiple related scalar variables defined across a common domain. Several approaches have been proposed for representing data in these situations. In this paper we focus on strategies for the visualization of multivariate data that rely on color mixing. In particular, through a series of controlled observer experiments, we seek to establish a fundamental understanding of the information-carrying capacities of two alternative methods for encoding multivariate information using color: color blending and color weaving. We begin with a baseline experiment in which we assess participants' abilities to accurately read numerical data encoded in six different basic color scales defined in the L*a*b* color space. We then assess participants' abilities to read combinations of 2, 3, 4 and 6 different data values represented in a common region of the domain, encoded using either color blending or color weaving. In color blending a single mixed color is formed via linear combination of the individual values in L*a*b* space, and in color weaving the original individual colors are displayed side-by-side in a high frequency texture that fills the region. A third experiment was conducted to clarify some of the trends regarding the color contrast and its effect on the magnitude of the error that was observed in the second experiment. The results indicate that when the component colors are represented side-by-side in a high frequency texture, most participants' abilities to infer the values of individual components are significantly improved, relative to when the colors are blended. Participants' performance was significantly better with color weaving particularly when more than 2 colors were used, and even when the individual colors subtended only 3 minutes of visual angle in the texture. However, the information-carrying capacity of the color weaving approach has its limits. We found that participants' abilities to accurately interpret each of the individual components in a high frequency color texture typically falls off as the number of components increases from 4 to 6. We found no significant advantages, in either color blending or color weaving, to using color scales based on component hues thatare more widely separated in the L*a*b* color space. Furthermore, we found some indications that extra difficulties may arise when opponent hues are employed. DA - 2007/// PY - 2007/// DO - 10.1109/TVCG.2007.70623 VL - 13 IS - 6 SP - 1270-1277 SN - 1941-0506 KW - color KW - perception KW - visualization KW - color weaving KW - color blending ER - TY - JOUR TI - Spare capacity provisioning for quasi-static traffic AU - Huang, Shu AU - Dutta, Rudra T2 - COMPUTER NETWORKS AB - Resource provisioning has for long been an important area of research in network design. The traffic grooming problem in optical networks is a design problem of aggregating sub-wavelength traffic demands onto lightpaths and lightpaths onto fiber links such that the required electronic switching capability, hence network cost, can be minimized. Because of the reconfiguration cost in optical grooming networks, a reactive resource provisioning approach may become inefficient, and result in revenue loss. In this paper, we propose an over-provisioning scheme, which pre-allocates the spare capacity of lightpaths to dynamic sub-wavelength traffic demands such that the network can be more agile in responding to traffic increment requests. For the single-link case, we formulate the problem as a non-linear programming problem, and for under reasonable assumptions, we prove the objective function is convex. We provide an exact algorithm to find the optimal solution. The problem with general topologies is then studied. We prove the NP-hardness in this case, and propose heuristics. Numerical results show our heuristics perform well. DA - 2007/12/19/ PY - 2007/12/19/ DO - 10.1016/j.comnet.2007.08.006 VL - 51 IS - 18 SP - 5011-5035 SN - 1872-7069 KW - networking KW - optical networking KW - resource provisioning KW - overprovisioning KW - reconfiguration ER - TY - CONF TI - On probabilistic analysis of randomization in hybrid symbolic-numeric algorithms AU - Kaltofen, E. AU - Yang, Z.-F. AU - Zhi, L.-H. C2 - 2007/// C3 - International Workshop on Symbolic-Numeric Computation: Proceedings DA - 2007/// PB - New York: ACM Press SN - 9781595937445 ER - TY - PAT TI - Methods, computer program products, and devices for calibrating chronically tissue implanted sensors using chronically tissue AU - Scarantino, C. W. AU - Nagle, H. T. AU - Kim, C.-S. AU - Ufer, S. AU - Fiering, J. AU - Kermani, B. G. C2 - 2007/// DA - 2007/// PY - 2007/// ER - TY - JOUR TI - Complexity of path traffic grooming AU - Iyer, Prashant AU - Dutta, Rudra AU - Savage, Carla D. T2 - JOURNAL OF OPTICAL NETWORKING AB - Feature Issue on Transmission in Optically Transparent Core NetworksThe problem of efficiently designing lightpaths and routing traffic on them in hybrid electro-optic data communication networks so that optical pass-through is maximized and the electronic switching cost is minimized is known as traffic grooming and has been studied extensively. Traffic grooming is known to be an inherently difficult problem. It has been shown to be NP-complete even for path networks, a simple topology in which lightpath wavelength assignment is tractable. In this paper, we explore the borderline between tractability and intractability by considering grooming in unidirectional path networks in which all traffic requests are destined for a single egress node. Whether the complete grooming problem is NP-hard with this restriction is an open question. We show that at least the problem of routing traffic on a given virtual topology to minimize electronic switching (NP-hard for path networks with arbitrary traffic matrices) becomes polynomial on the egress model. We also show that in the egress model, if the capacity constraint is relaxed, the entire problem becomes polynomial. If, in addition, traffic requests are uniform, we provide an explicit combinatorial formula for the optimum solution as well as an algorithm that constructs a routing that achieves this optimum. For the case of finite capacity and unit traffic requests, we show how to polynomially find a feasible solution that is optimal under reasonable assumptions. DA - 2007/11/1/ PY - 2007/11/1/ DO - 10.1364/JON.6.001270 VL - 6 IS - 11 SP - 1270-1281 SN - 1536-5379 ER - TY - JOUR TI - Source-code-correlated cache coherence characterization of OpenMP benchmarks AU - Marathe, Jaydeep AU - Mueller, Frank T2 - IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS AB - Cache coherence in shared-memory multiprocessor systems has been studied mostly from an architecture viewpoint, often by means of aggregating metrics. In many cases, aggregate events provide insufficient information for programmers to understand and optimize the coherence behavior of their applications. A better understanding would be given by source code correlations of not only aggregate events, but also finer granularity metrics directly linked to high-level source code constructs, such as source lines and data structures. In this paper, we explore a novel application-centric approach to studying coherence traffic. We develop a coherence analysis framework based on incremental coherence simulation of actual reference traces. We provide tool support to extract these reference traces and synchronization information from OpenMP threads at runtime using dynamic binary rewriting of the application executable. These traces are fed to ccSIM, our cache-coherence simulator. The novelty of ccSIM lies in its ability to relate low-level cache coherence metrics (such as coherence misses and their causative invalidations) to high-level source code constructs including source code locations and data structures. We explore the degree of freedom in interleaving data traces from different processors and assess simulation accuracy in comparison to metrics obtained from hardware performance counters. Our quantitative results show that: 1) Cache coherence traffic can be simulated with a considerable degree of accuracy for SPMD programs, as the invalidation traffic closely matches the corresponding hardware performance counters. 2) Detailed, high-level coherence statistics are very useful in detecting, isolating, and understanding coherence bottlenecks. We use ccSIM with several well-known benchmarks and find coherence optimization opportunities leading to significant reductions in coherence traffic and savings in wall-clock execution time DA - 2007/6// PY - 2007/6// DO - 10.1109/TPDS.2007.1058 VL - 18 IS - 6 SP - 818-834 SN - 1558-2183 KW - cache memories KW - simulation KW - dynamic binary rewriting KW - program instrumentation KW - SMPs KW - coherence protocols ER - TY - JOUR TI - Non-monotonic dose-response relationship in steroid hormone receptor-mediated gene expression AU - Li, Li AU - Andersen, Melvin E. AU - Heber, Steffen AU - Zhang, Qiang T2 - JOURNAL OF MOLECULAR ENDOCRINOLOGY AB - Steroid hormone receptors are the targets of many environmental endocrine active chemicals (EACs) and synthetic drugs used in hormone therapy. While most of these chemical compounds have a unidirectional and monotonic effect, certain EACs can display non-monotonic dose-response behaviors and some synthetic drugs are selective endocrine modulators. Mechanisms underlying these complex endocrine behaviors have not been fully understood. By formulating an ordinary differential equation-based computational model, we investigated in this study the steady-state dose-response behavior of exogenous steroid ligands in an endogenous hormonal background under various parameter conditions. Our simulation revealed that non-monotonic dose-responses in gene expression can arise within the classical genomic framework of steroid signaling. Specifically, when the exogenous ligand is an agonist, a U-shaped dose-response appears as a result of the inherently nonlinear process of receptor homodimerization. This U-shaped dose-response curve can be further modulated by mixed-ligand heterodimers formed between endogenous ligand-bound and exogenous ligand-bound receptor monomers. When the heterodimer is transcriptionally inactive or repressive, the magnitude of U-shape increases; conversely, when the heterodimer is transcriptionally active, the magnitude of U-shape decreases. Additionally, we found that an inverted U-shaped dose-response can arise when the heterodimer is a strong transcription activator regardless of whether the exogenous ligand is an agonist or antagonist. Our work provides a novel mechanism for non-monotonic, particularly U-shaped, dose-response behaviors observed with certain steroid mimics, and may help not only understand how selective steroid receptor modulators work but also improve risk assessment for EACs. DA - 2007/// PY - 2007/// DO - 10.1677/JME-07-0003 VL - 38 IS - 5-6 SP - 569-585 SN - 1479-6813 ER - TY - JOUR TI - Efficiently querying large XML data repositories: A survey AU - Gou, Gang AU - Chirkova, Rada T2 - IEEE TRANSACTIONS ON KNOWLEDGE AND DATA ENGINEERING AB - Extensible markup language (XML) is emerging as a de facto standard for information exchange among various applications on the World Wide Web. There has been a growing need for developing high-performance techniques to query large XML data repositories efficiently. One important problem in XML query processing is twig pattern matching, that is, finding in an XML data tree D all matches that satisfy a specified twig (or path) query pattern Q. In this survey, we review, classify, and compare major techniques for twig pattern matching. Specifically, we consider two classes of major XML query processing techniques: the relational approach and the native approach. The relational approach directly utilizes existing relational database systems to store and query XML data, which enables the use of all important techniques that have been developed for relational databases, whereas in the native approach, specialized storage and query processing systems tailored for XML data are developed from scratch to further improve XML query performance. As implied by existing work, XML data querying and management are developing in the direction of integrating the relational approach with the native approach, which could result in higher query processing performance and also significantly reduce system reengineering costs. DA - 2007/10// PY - 2007/10// DO - 10.1109/tkde.2007.1060 VL - 19 IS - 10 SP - 1381-1403 SN - 1041-4347 KW - XML query processing KW - twig pattern matching ER - TY - JOUR TI - Analyzing the energy-time trade-off in high-performance computing applications AU - Freeh, Vincent W. AU - Lowenthal, David K. AU - Pan, Feng AU - Kappiah, Nandini AU - Springer, Rob AU - Rountree, Barry L. AU - Femal, Mark E. T2 - IEEE TRANSACTIONS ON PARALLEL AND DISTRIBUTED SYSTEMS AB - Although users of high-performance computing are most interested in raw performance both energy and power consumption has become critical concerns. One approach to lowering energy and power is to use high-performance cluster nodes that have several power-performance states so that the energy-time trade-off can be dynamically adjusted. This paper analyzes the energy-time trade-off of a wide range of applications-serial and parallel-on a power-scalable cluster. We use a cluster of frequency and voltage-scalable AMD-64 nodes, each equipped with a power meter. We study the effects of memory and communication bottlenecks via direct measurement of time and energy. We also investigate metrics that can, at runtime, predict when each type of bottleneck occurs. Our results show that, for programs that have a memory or communication bottleneck, a power-scalable cluster can save significant energy with only a small time penalty. Furthermore, we find that, for some programs, it is possible to both consume less energy and execute in less time by increasing the number of nodes while reducing the frequency-voltage setting of each node DA - 2007/6// PY - 2007/6// DO - 10.1109/TPDS.2007.1026 VL - 18 IS - 6 SP - 835-848 SN - 1558-2183 KW - high-performance computing KW - power-aware computing ER - TY - JOUR TI - A roadmap for COMPREHENSIVE online privacy policy management AU - Anton, Annie I. AU - Bertino, Elisa AU - Li, Ninghui AU - Yu, Ting T2 - COMMUNICATIONS OF THE ACM AB - A framework supporting the privacy policy life cycle helps guide the kind of research to consider before sound privacy answers may be realized. DA - 2007/7// PY - 2007/7// DO - 10.1145/1272516.1272522 VL - 50 IS - 7 SP - 109-116 SN - 1557-7317 ER - TY - JOUR TI - View selection for real conjunctive queries AU - Afrati, Foto AU - Chirkova, Rada AU - Gergatsoulis, Manolis AU - Pavlaki, Vassia T2 - ACTA INFORMATICA DA - 2007/9// PY - 2007/9// DO - 10.1007/s00236-007-0046-z VL - 44 IS - 5 SP - 289-321 SN - 1432-0525 ER - TY - JOUR TI - Reflections on 10 years of sponsored senior design projects: Students win-clients win! AU - Fornaro, Robert J. AU - Heil, Margaret R. AU - Tharp, Alan L. T2 - JOURNAL OF SYSTEMS AND SOFTWARE AB - Undergraduate computer science degree programs often provide an opportunity for students to experience real software projects as a part of their programs of study. These experiences frequently reside in a course in which students form software development teams, are assigned to a project offered by a corporate sponsor and devote one or two semesters to the task of making progress on the project. In an ideal model, faculty mentor student teams who, in turn, behave as subcontractors or consultants to the sponsor. Students work for a grade, not directly for the sponsor as a true subcontractor would. In the ideal model, students demonstrate what they have learned about software engineering process, as well as their ability to implement programmed solutions. Student teams provide progress reports, both oral and written, and directly experience many of the challenges and successes of true software engineering professionals. This paper reports on one such program after 10 years of operation. The technologies and software development processes of student projects are summarized and presented as an informal survey. Student response is discussed in terms of software systems they produced and how they went about producing them. The maturation of these students as software engineering professionals is also discussed. DA - 2007/8// PY - 2007/8// DO - 10.1016/j.jss.2006.09.052 VL - 80 IS - 8 SP - 1209-1216 SN - 1873-1228 KW - capstone course KW - software engineering KW - professional communication ER - TY - JOUR TI - On the design of more secure software-intensive systems by use of attack patterns AU - Gegick, Michael AU - Williams, Laurie T2 - INFORMATION AND SOFTWARE TECHNOLOGY AB - Retrofitting security implementations to a released software-intensive system or to a system under development may require significant architectural or coding changes. These late changes can be difficult and more costly than if performed early in the software process. We have created regular expression-based attack patterns that show the sequential events that occur during an attack. By performing a Security Analysis for Existing Threats (SAFE-T), software engineers can match the symbols of a regular expression to their system design. An architectural analysis that identifies security vulnerabilities early in the software process can prepare software engineers for which security implementations are necessary when coding starts. A case study involving students in an upper-level undergraduate security course suggests that SAFE-T can be performed by relatively inexperienced engineers who are not experts in security. Data from the case study also suggest that the attack patterns do not restrict themselves to vulnerabilities in specific environments. DA - 2007/4// PY - 2007/4// DO - 10.1016/j.infsof.2006.06.002 VL - 49 IS - 4 SP - 381-397 SN - 1873-6025 KW - software and system safety KW - patterns ER - TY - CONF TI - On exact and approximate interpolation of sparse rational functions AU - Kaltofen, E. AU - Yang, Z.-F. AB - The black box algorithm for separating the numerator from the denominator of a multivariate rational function can be combined with sparse multivariate polynomial interpolation algorithms to interpolate a sparse rational function. domization and early termination strategies are exploited to minimize the number of black box evaluations. In addition, rational number coefficients are recovered from modular images by rational vector recovery. The need for separate numerator and denominator size bounds is avoided via correction, and the modulus is minimized by use of lattice basis reduction, a process that can be applied to sparse rational function vector recovery itself. Finally, one can deploy sparse rational function interpolation algorithm in the hybrid symbolic-numeric setting when the black box for the function returns real and complex values with noise. We present and analyze five new algorithms for the above problems and demonstrate their effectiveness on a mark implementation. C2 - 2007/// C3 - ISSAC 2007: International Symposium for Symbolic and Algebraic Computation: Proceedings DA - 2007/// DO - 10.1145/1277548.1277577 PB - New York: ACM Press SN - 9781595937438 ER - TY - JOUR TI - Modeling and evaluating empathy in embodied companion agents AU - McQuiggan, Scott W. AU - Lester, James C. T2 - INTERNATIONAL JOURNAL OF HUMAN-COMPUTER STUDIES AB - Affective reasoning plays an increasingly important role in cognitive accounts of social interaction. Humans continuously assess one another's situational context, modify their own affective state accordingly, and then respond to these outcomes by expressing empathetic behaviors. Synthetic agents serving as companions should respond similarly. However, empathetic reasoning is riddled with the complexities stemming from the myriad factors bearing upon situational assessment. A key challenge posed by affective reasoning in synthetic agents is devising empirically informed models of empathy that accurately respond in social situations. This paper presents Care, a data-driven affective architecture and methodology for learning models of empathy by observing human–human social interactions. First, in Care training sessions, one trainer directs synthetic agents to perform a sequence of tasks while another trainer manipulates companion agents’ affective states to produce empathetic behaviors (spoken language, gesture, and posture). Care tracks situational data including locational, intentional, and temporal information to induce a model of empathy. At runtime, Care uses the model of empathy to drive situation-appropriate empathetic behaviors. Care has been used in a virtual environment testbed. Two complementary studies investigating the predictive accuracy and perceived accuracy of Care-induced models of empathy suggest that the Care paradigm can provide the basis for effective empathetic behavior control in embodied companion agents. DA - 2007/4// PY - 2007/4// DO - 10.1016/j.ijhcs.2006.11.015 VL - 65 IS - 4 SP - 348-360 SN - 1095-9300 ER - TY - JOUR TI - Impact of background traffic on performance of high-speed TCP variant protocols AU - Ha, S. T. AU - Le, L. AU - Rhee, I. AU - Xu, L. S. T2 - Computer Networks (Amsterdam, Netherlands : 1999) AB - This paper examines the effect of background traffic on the performance of existing high-speed TCP variant protocols, namely BIC-TCP, CUBIC, FAST, HSTCP, H-TCP and Scalable TCP. We demonstrate that the stability, link utilization, convergence speed and fairness of the protocols are clearly affected by the variability of flow sizes and round-trip times (RTTs), and the amount of background flows competing with high-speed flows in a bottleneck router. Our findings include: (1) the presence of background traffic with variable flow sizes and RTTs improves the fairness of most high-speed protocols, (2) all protocols except FAST and HSTCP show good intra-protocol fairness regardless of the types of background traffic, (3) HSTCP needs a larger amount of background traffic and more variable traffic than the other protocols to achieve convergence, (4) H-TCP trades stability for fairness; that is, while its fairness is good independent of background traffic types, larger variance in the flow sizes and RTTs of background flows causes the protocol to induce a higher degree of global loss synchronization among competing flows, lowering link utilization and stability, (5) FAST suffers unfairness and instability in small buffer or long delay networks regardless of background traffic types, and (6) the fairness of high-speed protocols depends more on the amount of competing background traffic rather than its rate variability. We also find that the presence of high-speed flows does not greatly reduce the bandwidth usage of background Web traffic. DA - 2007/// PY - 2007/// DO - 10.1016/j.comnet.2006.11.005 VL - 51 IS - 7 SP - 1748-1762 ER - TY - JOUR TI - An independent component analysis approach for minimizing effects of recirculation in dynamic susceptibility contrast magnetic resonance imaging AU - Wu, Yang AU - An, Hongyu AU - Krim, Hamid AU - Lin, Weili T2 - JOURNAL OF CEREBRAL BLOOD FLOW AND METABOLISM AB - In dynamic susceptibility contrast (DSC) perfusion-weighted imaging, effects of recirculation are normally minimized by a gamma-variate fitting procedure of the concentration curves before estimating hemodynamic parameters. The success of this method, however, hinges largely on the extent to which magnetic resonance signal is altered in the presence of a contrast agent and a temporal separation between the first and subsequent passages of the contrast agent. Moreover, important physiologic information might be compromised by imposing an analytic equation to all measured concentration curves. This investigation proposes to exploit independent component analysis to minimize effects of recirculation in DSC. Results obtained from simulation, normal healthy volunteers, and acute stroke patients show that such a technique can greatly minimize the effects of recirculation despite a substantial overlap between the first passage and recirculation. This in turn should improve estimation of cerebral hemodynamics particularly when an overlap between the first passage and recirculation is suspected as in an ischemic lesion. DA - 2007/3// PY - 2007/3// DO - 10.1038/sj.jcbfm.9600374 VL - 27 IS - 3 SP - 632-645 SN - 1559-7016 KW - cerebral ischemia KW - dynamic susceptibility contrast KW - gamma-variate fitting KW - independent component analysis KW - perfusion-weighted imaging KW - recirculation ER - TY - JOUR TI - Performance analysis of an ingress switch in a JumpStart optical burst switching network AU - Xu, Lisong AU - Perros, Harry G. T2 - PERFORMANCE EVALUATION AB - We consider an ingress optical burst switching (OBS) node employing the JumpStart signaling protocol. The switch serves a number of users, each connected to the switch with a fiber link that supports multiple wavelengths. Each wavelength is associated with a 3-state Markovian burst arrival process which permits short and long bursts to be modeled. We model the ingress switch as a closed multi-class non-product-form queueing network, which we analyze approximately by decomposition. Specifically, we develop new techniques to analyze the queueing network, first assuming a single class of customers, and subsequently multiple classes of customers. These analytical techniques have applications to general queueing networks beyond the one studied in this paper. We also develop computationally efficient approximate algorithms to analyze an ingress switch in the limiting case where the number of wavelengths is large. The algorithms have a good accuracy, and they provide insight into the effect of various system parameters on the performance of an ingress OBS switch. DA - 2007/5// PY - 2007/5// DO - 10.1016/j.peva.2006.05.012 VL - 64 IS - 4 SP - 315-346 SN - 1872-745X KW - optical burst switching KW - JumpStart project KW - Marie's algorithm KW - multi-class queueing networks KW - closed non-product-form queueing networks ER - TY - JOUR TI - METRIC: Memory tracing via dynamic binary rewriting to identify cache inefficiencies AU - Marathe, Jaydeep AU - Mueller, Frank AU - Mohan, Tushar AU - McKee, Sally A. AU - De Supinski, Bronis R. AU - Yoo, Andy T2 - ACM TRANSACTIONS ON PROGRAMMING LANGUAGES AND SYSTEMS AB - With the diverging improvements in CPU speeds and memory access latencies, detecting and removing memory access bottlenecks becomes increasingly important. In this work we present METRIC, a software framework for isolating and understanding such bottlenecks using partial access traces. METRIC extracts access traces from executing programs without special compiler or linker support. We make four primary contributions. First, we present a framework for extracting partial access traces based on dynamic binary rewriting of the executing application. Second, we introduce a novel algorithm for compressing these traces. The algorithm generates constant space representations for regular accesses occurring in nested loop structures. Third, we use these traces for offline incremental memory hierarchy simulation. We extract symbolic information from the application executable and use this to generate detailed source-code correlated statistics including per-reference metrics, cache evictor information, and stream metrics. Finally, we demonstrate how this information can be used to isolate and understand memory access inefficiencies. This illustrates a potential advantage of METRIC over compile-time analysis for sample codes, particularly when interprocedural analysis is required. DA - 2007/3// PY - 2007/3// DO - 10.1145/1216374.1216380 VL - 29 IS - 2 SP - SN - 1558-4593 KW - algorithms KW - languages KW - performance KW - dynamic binary rewriting KW - program instrumentation KW - data trace generation KW - data trace compression KW - cache analysis ER - TY - JOUR TI - Generalized wavelength sharing policies for absolute QoS guarantees in OBS networks AU - Yang, Li AU - Rouskas, George N. T2 - IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS AB - We consider the problem of supporting absolute QoS guarantees in terms of the end-to-end burst loss in OBS networks. We present a parameterized model for wavelength sharing which provides for isolation among different traffic classes while also making efficient use of wavelength capacity through statistical multiplexing. We develop a heuristic to optimize the policy parameters for a single link of an OBS network. We also develop a methodology for translating the end-to-end QoS requirements into appropriate per-link parameters so as to provide network-wide guarantees. Our approach is easy to implement, it can support a wide variety of traffic classes, and is effective in meeting the QoS requirements and keeping the loss rate of best-effort and overall traffic low DA - 2007/4// PY - 2007/4// DO - 10.1109/TWC.2007.026706 VL - 25 IS - 4 SP - 93-104 SN - 1558-0008 KW - optical burst switching KW - wavelength division multiplexing KW - resource sharing policies KW - quality of service ER - TY - JOUR TI - Story and discourse: A bipartite model of narrative generation in virtual worlds AU - Young, R. Michael T2 - Interaction Studies AB - In this paper, we set out a basic approach to the modeling of narrative in interactive virtual worlds. This approach adopts a bipartite model taken from narrative theory, in which narrative is composed of story and discourse . In our approach, story elements — plot and character — are defined in terms of plans that drive the dynamics of a virtual environment. Discourse elements — the narrative’s communicative actions — are defined in terms of discourse plans whose communicative goals include conveying the story world plan’s structure. To ground the model in computational terms, we provide examples from research under way in the Liquid Narrative Group involving the design of the Mimesis system, an architecture for intelligent interactive narrative incorporating concepts from artificial intelligence, narrative theory, cognitive psychology and computational linguistics. DA - 2007/// PY - 2007/// DO - 10.1075/is.8.2.02you VL - 8 IS - 2 SP - 177-208 J2 - IS LA - en OP - SN - 1572-0373 1572-0381 UR - http://dx.doi.org/10.1075/is.8.2.02you DB - Crossref KW - interactive narrative KW - artificial intelligence KW - planning KW - cognitive models KW - suspense KW - discourse generation ER - TY - JOUR TI - Simulation of fusion plasmas: Current status and future direction AU - Batchelor, D. A. AU - Beck, M. AU - Becoulet, A. AU - Budny, R. V. AU - Chang, C. S. AU - Diamond, P. H. AU - Dong, J. Q. AU - Fu, G. Y. AU - Fukuyama, A. AU - Hahm, T. S. AU - Keyes, D. E. AU - Kishimoto, Y. AU - Klasky, S. AU - Lao, L. L. AU - Li, K. AU - Lin, Z. AU - Ludaescher, B. AU - Manickam, J. AU - Nakajima, N. AU - a, T2 - Plasma Science & Technology DA - 2007/// PY - 2007/// VL - 9 IS - 3 SP - 312-387 ER - TY - JOUR TI - Cost-effective single-hub WDM ring networks: A proposal and analysis AU - Bouabdallah, N. AU - Perros, H. T2 - Computer Networks (Amsterdam, Netherlands : 1999) AB - In this paper, we study a new concept of traffic grooming in wavelength-division multiplexing (WDM) ring networks that aims at eliminating both the bandwidth underutilization and the scalability concerns that are typical of all-optical wavelength routed ring networks. Our objective is to reduce the network cost while preserving the benefits of all-optical WDM ring networks. In order to assess the efficiency of our proposal, all underlying network costs are compared. These costs include that of the transceivers required at node level, as well as the number of wavelengths. Our results show that the proposed aggregation technique can significantly improve the resource utilization while reducing the network cost. DA - 2007/// PY - 2007/// DO - 10.1016/j.comnet.2007.04.014 VL - 51 IS - 13 SP - 3878-3901 ER - TY - JOUR TI - Confronting the American dream: Nicaragua under US imperial rule. AU - Mitchell, N. T2 - International History Review DA - 2007/// PY - 2007/// VL - 29 IS - 2 SP - 382-383 ER - TY - JOUR TI - Incorporating performance testing in test-driven development AU - Johnson, Michael J. AU - Maximilien, E. Michael AU - Ho, Chih-Wei AU - Williams, Laurie T2 - IEEE SOFTWARE AB - Performance design and performance testing are necessarily different from functional test case design. A rigorous test-driven design methodology isn't practical for all performance measurement. A test-first approach to performance provides some advantages in a TDD environment. Experience with applying early performance testing in a TDD framework for a device-driver development project provides insight into the test-first approach. The results show a trend of performance improvement throughout the development life cycle, and better performance compared to an earlier release. Lessons learned include the benefit of having a performance architect on the development team and of tracking performance measurements throughout the development life cycle.This article is part of a special issue on test-driven development. DA - 2007/// PY - 2007/// DO - 10.1109/MS.2007.77 VL - 24 IS - 3 SP - 67-+ SN - 1937-4194 ER - TY - JOUR TI - Ultrasonic assessment of early-age changes in the material properties of cementitious materials AU - Subramaniam, Kolluru V. AU - Lee, Jaejun T2 - MATERIALS AND STRUCTURES DA - 2007/4// PY - 2007/4// DO - 10.1617/s11527-006-9107-y VL - 40 IS - 3 SP - 301-309 SN - 1871-6873 ER - TY - BOOK TI - Security for wireless sensor networks AU - Liu, D.-G. AU - Ning, P. CN - TK7872 .D48 L48 2007 DA - 2007/// PY - 2007/// PB - New York: Springer SN - 9780387327235 ER - TY - JOUR TI - HIPAA's effect on web site privacy policies AU - Anton, Annie I. AU - Earp, Julia B. AU - Vail, Matthew W. AU - Jain, Neha AU - Gheen, Carrie M. AU - Frink, Jack M. T2 - IEEE SECURITY & PRIVACY AB - Healthcare institutions typically post their privacy practices online as privacy policy documents. We conducted a longitudinal study that examines the effects of HIPAA's enactment on a collection of privacy policy documents for a fixed set of organizations over a four-year period. We present our analysis of 24 healthcare privacy policy documents from nine healthcare Web sites, analyzed using goal mining, a content-analysis method that supports extraction of useful information about institutions' privacy practices from documents. We compare our results to our pre-HIPAA study of these same institutions' online privacy practices and evaluate their evolution in the presence of privacy laws DA - 2007/// PY - 2007/// DO - 10.1109/MSP.2007.7 VL - 5 IS - 1 SP - 45-52 SN - 1540-7993 ER - TY - JOUR TI - The directional p-median problem: Definition, complexity, and algorithms AU - Jackson, Laura E. AU - Rouskas, George N. AU - Stallmann, Matthias F. M. T2 - EUROPEAN JOURNAL OF OPERATIONAL RESEARCH AB - An instance of a p-median problem gives n demand points. The objective is to locate p supply points in order to minimize the total distance of the demand points to their nearest supply point. p-Median is polynomially solvable in one dimension but NP-hard in two or more dimensions, when either the Euclidean or the rectilinear distance measure is used. In this paper, we treat the p-median problem under a new distance measure, the directional rectilinear distance, which requires the assigned supply point for a given demand point to lie above and to the right of it. In a previous work, we showed that the directional p-median problem is polynomially solvable in one dimension; we give here an improved solution through reformulating the problem as a special case of the constrained shortest path problem. We have previously proven that the problem is NP-complete in two or more dimensions; we present here an efficient heuristic to solve it. Compared to the robust Teitz and Bart heuristic, our heuristic enjoys substantial speedup while sacrificing little in terms of solution quality, making it an ideal choice for real-world applications with thousands of demand points. DA - 2007/6/16/ PY - 2007/6/16/ DO - 10.1016/j.ejor.2005.06.080 VL - 179 IS - 3 SP - 1097-1108 SN - 0377-2217 KW - directional p-median problem KW - traffic quantization KW - vector quantization ER - TY - BOOK TI - Secure data management in decentralized systems AB - Database security is one of the classical topics in the research of information system security. Ever since the early years of database management systems, a great deal of research activity has been c DA - 2007/// PY - 2007/// DO - 10.1007/978-0-387-27696-0 PB - New York: Springer SN - 0387276947 ER - TY - JOUR TI - On the impact of quality of protection in wireless local area networks with IP mobility AU - Agarwal, Avesh K. AU - Wang, Wenye T2 - MOBILE NETWORKS & APPLICATIONS DA - 2007/2// PY - 2007/2// DO - 10.1007/s11036-006-0009-6 VL - 12 IS - 1 SP - 93-110 SN - 1572-8153 KW - wireless local area networks KW - quality of service KW - quality of protection KW - security protocols KW - mobile IP KW - performance analysis ER - TY - JOUR TI - Correcting base-assignment errors in repeat regions of shotgun assembly AU - Zhi, Degui AU - Keich, Uri AU - Pevzner, Pavel AU - Heber, Steffen AU - Tang, Haixu T2 - IEEE-ACM TRANSACTIONS ON COMPUTATIONAL BIOLOGY AND BIOINFORMATICS AB - Accurate base-assignment in repeat regions of a whole genome shotgun assembly is an unsolved problem. Since reads in repeat regions cannot be easily attributed to a unique location in the genome, current assemblers may place these reads arbitrarily. As a result, the base-assignment error rate in repeats is likely to be much higher than that in the rest of the genome. We developed an iterative algorithm, EULER-AIR, that is able to correct base-assignment errors in finished genome sequences in public databases. The Wolbachia genome is among the best finished genomes. Using this genome project as an example, we demonstrated that EULER-AIR can 1) discover and correct base-assignment errors, 2) provide accurate read assignments, 3) utilize finishing reads for accurate base-assignment, and 4) provide guidance for designing finishing experiments. In the genome of Wolbachia, EULER-AIR found 16 positions with ambiguous base-assignment and two positions with erroneous bases. Besides Wolbachia, many other genome sequencing projects have significantly fewer finishing reads and, hence, are likely to contain more base-assignment errors in repeats. We demonstrate that EULER-AIR is a software tool that can be used to find and correct base-assignment errors in a genome assembly project. DA - 2007/// PY - 2007/// DO - 10.1109/TCBB.2007.1005 VL - 4 IS - 1 SP - 54-64 SN - 1557-9964 KW - fragment assembly KW - finishing KW - expectation maximization ER - TY - JOUR TI - An algebra for commitment protocols AU - Mallya, Ashok U. AU - Singh, Munindar P. T2 - AUTONOMOUS AGENTS AND MULTI-AGENT SYSTEMS DA - 2007/4// PY - 2007/4// DO - 10.1007/s10458-006-7232-1 VL - 14 IS - 2 SP - 143-163 SN - 1573-7454 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-33846465461&partnerID=MN8TOARS KW - commitments KW - interaction protocols KW - formal methods KW - multiagent system modelling and design ER - TY - JOUR TI - Flexible skew-symmetric shape model for shape representation, classification, and sampling AU - Baloch, Sajjad H. AU - Krim, Hamid T2 - IEEE TRANSACTIONS ON IMAGE PROCESSING AB - Skewness of shape data often arises in applications (e.g., medical image analysis) and is usually overlooked in statistical shape models. In such cases, a Gaussian assumption is unrealistic and a formulation of a general shape model which accounts for skewness is in order. In this paper, we present a novel statistical method for shape modeling, which we refer to as the flexible skew-symmetric shape model (FSSM). The model is sufficiently flexible to accommodate a departure from Gaussianity of the data and is fairly general to learn a "mean shape" (template), with a potential for classification and random generation of new realizations of a given shape. Robustness to skewness results from deriving the FSSM from an extended class of flexible skew-symmetric distributions. In addition, we demonstrate that the model allows us to extract principal curves in a point cloud. The idea is to view a shape as a realization of a spatial random process and to subsequently learn a shape distribution which captures the inherent variability of realizations, provided they remain, with high probability, within a certain neighborhood range around a mean. Specifically, given shape realizations, FSSM is formulated as a joint bimodal distribution of angle and distance from the centroid of an aggregate of random points. Mean shape is recovered from the modes of the distribution, while the maximum likelihood criterion is employed for classification. DA - 2007/2// PY - 2007/2// DO - 10.1109/TIP.2006.888348 VL - 16 IS - 2 SP - 317-328 SN - 1941-0042 KW - flexible skew-symmetric distributions (FSSM) KW - principal curves KW - sampling KW - shape classification KW - shape modeling KW - template learning ER -