TY - JOUR TI - Mixed integer linear programming model for multi-commodity multi-depot inventory routing problem AU - Ramkumar, N. AU - Subramanian, P. AU - Narendran, T. T. AU - Ganesh, K. T2 - OPSEARCH DA - 2012/5/22/ PY - 2012/5/22/ DO - 10.1007/s12597-012-0087-0 VL - 49 IS - 4 SP - 413-429 J2 - OPSEARCH LA - en OP - SN - 0030-3887 0975-0320 UR - http://dx.doi.org/10.1007/s12597-012-0087-0 DB - Crossref ER - TY - JOUR TI - A technical note on ‘Analysis of closed loop supply chain using genetic algorithm and particle swarm optimisation’ AU - Subramanian, P. AU - Ramkumar, N. AU - Narendran, T.T. AU - Ganesh, K. T2 - International Journal of Production Research AB - This study analyses the mixed-integer linear program (MILP) proposed by Kannan et al. [Kannan, G., Noorul Hag, A., and Devika, M., 2009. Analysis of closed loop supply chain using genetic algorithm and particle swarm optimization. International Journal of Production Research, 47 (5), 1175–1200] in their paper entitled ‘Analysis of closed loop supply chain using genetic algorithm and particle swarm optimisation’. Since we find inconsistencies in the model, we propose modifications to rectify the flaws. The revised model is presented and tested using a hypothetical problem. DA - 2012/1/15/ PY - 2012/1/15/ DO - 10.1080/00207543.2011.593348 VL - 50 IS - 2 SP - 593-602 J2 - International Journal of Production Research LA - en OP - SN - 0020-7543 1366-588X UR - http://dx.doi.org/10.1080/00207543.2011.593348 DB - Crossref ER - TY - JOUR TI - DESIGN OF A HIGH-BANDWIDTH XY NANOPOSITIONING STAGE FOR HIGH-THROUGHPUT MICRO/NANO MANUFACTURING AU - Polit, Sebastian AU - Dong, Jingyan AU - ASME T2 - Proceedings of the Asme International Mechanical Engineering Congress and Exposition 2010, Vol 3, Pts a and B DA - 2012/// PY - 2012/// SP - 709-718 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000320286400084&KeyUID=WOS:000320286400084 ER - TY - JOUR TI - DIRECT-DEPOSITION AND MULTIPLE MATERIALS INTEGRATION OF TISSUE ENGINEERING SCAFFOLDS AU - Wei, Chuang AU - Sonawane, Bhushan AU - Cai, Lei AU - Wang, Shanfeng AU - Dong, Jingyan AU - ASME T2 - Proceedings of the Asme International Mechanical Engineering Congress and Exposition 2010, Vol 3, Pts a and B DA - 2012/// PY - 2012/// SP - 1083-1088 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000320286400130&KeyUID=WOS:000320286400130 ER - TY - CONF TI - Multi-material fabrication of tissue engineering scaffold AU - Wei, C. AU - Lei, C. AU - Wang, S. AU - Dong, J. C2 - 2012/// C3 - Transactions of the North American Manufacturing Research Institution of SME DA - 2012/// VL - 40 SP - 126-132 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84869826114&partnerID=MN8TOARS ER - TY - CONF TI - Ultrasonic vibration assisted nanomachining on PMMA with an AFM AU - Zhang, L. AU - Dong, J. C2 - 2012/// C3 - Technical Paper - Society of Manufacturing Engineers DA - 2012/// VL - TP12PUB71 SP - 631-637 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84880696152&partnerID=MN8TOARS ER - TY - JOUR TI - A SOI-MEMS-BASED SINGLE AXIS ACTIVE PROBE FOR CELLULAR FORCE SENSING AND CELL MANIPULATION AU - Zhang, Li AU - Dong, Jingyan AU - ASME T2 - Proceedings of the Asme International Mechanical Engineering Congress and Exposition (Imece 2010), Vol 10 AB - This paper presents the design, analysis, fabrication, and characterization of an electrostatically driven single axis active probing device for cellular force sensing and cell manipulation applications. The active probe is actuated by linear comb driver to create the motion in the probing direction. Both actuation and sensing comb drives are designed for the probing stage. The sensing comb structures enable us to sense the probe displacement when it is actuated, which enables application of force balanced sensing. The designed active probing device has an overall size of 5 mm × 4.5 mm, is fabricated on a silicon-on-insulator (SOI) substrate through surface micromachining technologies and deep reactive-ion etching (DRIE) process. The probe stage structure is fabricated on the 10-μm-thick device layer of SOI wafer. The handle layer beneath probe stage is etched away by DRIE process to decrease the film damping between the stage and the handle wafer thus achieving high quality factor. The proposed single axis probe is aimed at sensing cellular force which ranges from pN to μN and cell manipulation applications. DA - 2012/// PY - 2012/// DO - 10.1115/IMECE2010-37924 SP - 537-542 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000320481100072&KeyUID=WOS:000320481100072 ER - TY - CONF TI - Performance of an Iterative Production Planning Approach for Production Systems with Manufacturing Flexibility AU - Albey, E. AU - Bilge, U. AU - Uzsoy, R. T2 - Workshop on Production Economics C2 - 2012/2// CY - Innsbruck, Austria DA - 2012/2// PY - 2012/2// ER - TY - CONF TI - Modeling for Equitable Food Distribution Under Capacity Constraints AU - Ivy, J.S. AU - Sengul, I. AU - Uzsoy, R. T2 - Industrial and Systems Engineering Research Conference C2 - 2012/5// CY - Orlando, FL DA - 2012/5// PY - 2012/5// ER - TY - CONF TI - Engineering Process Improvement for Wafer Fabrication AU - Kim, S. AU - Uzsoy, R. T2 - 23rd Advanced Semiconductor Manufacturing Conference C2 - 2012/5// CY - Saratoga Springs, NY DA - 2012/5// PY - 2012/5// ER - TY - JOUR TI - Multiple Time Scales in Production Planning: Clearing Functions, Discrete-Event Simulation and Partial Differential Equations AU - Armbruster, D. AU - Uzsoy, R. T2 - Tutorials in Operations Research DA - 2012/// PY - 2012/// ER - TY - ER - TY - BOOK TI - Optimizing Risk Management in Services A3 - Fang, S. A3 - Wu, D. A3 - Olson, D.L. A3 - Birge, J.R. DA - 2012/// PY - 2012/// VL - 61 ER - TY - BOOK TI - The First World Congress on Global Optimization in Engineering and Science A3 - Floudas, A. A3 - Fang, S. A3 - Gao, David Y. DA - 2012/// PY - 2012/// VL - 54 ER - TY - JOUR TI - Analysis on Transport Costs and China’s Exports AU - Transport Costs, Analysis AU - Exports, China’s AU - Xu, L. Z. AU - Wang, S.Y. T2 - Systems Engineering Theory and Practice DA - 2012/// PY - 2012/// VL - 32 IS - 5 SP - 1057–1067 ER - TY - JOUR TI - Modeling and grinding large sculptured surface by robotic digitization AU - Park, J. W. AU - Cho, H. U. AU - Chung, C. W. AU - Lee, Y. S. AU - Jeon, D. J. T2 - Journal of Mechanical Science and Technology DA - 2012/7// PY - 2012/7// DO - 10.1007/S12206-012-0520-6 VL - 26 IS - 7 SP - 2087-2091 J2 - J Mech Sci Technol LA - en OP - SN - 1738-494X 1976-3824 UR - http://dx.doi.org/10.1007/S12206-012-0520-6 DB - Crossref KW - Robot KW - Digitization KW - Surface modeling KW - Grinding KW - Marine propeller ER - TY - CHAP TI - Modeling equity for allocation in public resources AU - Leclerc, P.D. AU - McLay, L.A. AU - Mayorga, M.E. T2 - Community-Based Operations Research: Decision Modeling for Local Impact and Diverse Populations A2 - Johnson, M. T3 - International Series in Operations Research & Management Science PY - 2012/// ET - 1 SP - 97-118 PB - Springer SV - 167 ER - TY - CONF TI - BrailleKey: An alternative Braille text input system: Comparative study of an innovative simplified text input system for the visually impaired AU - Subash, N.S. AU - Nambiar, S. AU - Kumar, V. AB - This paper explores the efficacy of using an alternate text input system for the blind, based entirely on Braille alphabets for touch-screen mobile devices. A comparative study was performed wherein a prototype application developed by the authors was compared against the Voice-Over technology developed for iOS (Apple's mobile operating system. The study conducted on five blind subjects show that this system can be used as a viable alternative to the existing input methods that have been developed for this purpose. C2 - 2012/// C3 - 4th International Conference on Intelligent Human Computer Interaction: Advancing Technology for Humanity, IHCI 2012 DA - 2012/// DO - 10.1109/IHCI.2012.6481790 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84875701592&partnerID=MN8TOARS ER - TY - CHAP TI - A Study on the Relationship between Pleasures and Design Attributes of Digital Appliances AU - Bahn, S. AU - Song, J. AU - Yun, M.H. AU - Nam, C.S. T2 - Advances in Affective and Pleasurable Design A2 - Ji, Y.G. PY - 2012/// SP - 222–230 PB - CRC Press SN - 9780429064890 ER - TY - JOUR TI - Maternal Pre-Pregnancy Weight and Gestational Weight Gain and Their Association with Birthweight with a Focus on Racial Differences AU - Hunt, Kelly J. AU - Alanis, Mark C. AU - Johnson, Erica R. AU - Mayorga, Maria E. AU - Korte, Jeffrey E. T2 - Maternal and Child Health Journal AB - Our objectives were to examine the interaction between maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) and their association with birthweight, with a focus on racial differences. We used birth certificate data from live singleton births of South Carolina resident mothers, who self-reported their race as non-Hispanic white (NHW, n = 140, 128) or non-Hispanic black (NHB, n = 82,492) and who delivered at 34–44 weeks of gestation between 2004 and 2008 to conduct a cross-sectional study. Linear regression was used to examine the relationship between our exposures (i.e., race, BMI and GWG) and our outcome birthweight. Based on 2009 Institute of Medicine guidelines, the prevalence of adequate, inadequate and excessive GWG was 27.1, 24.2 and 48.7%, respectively, in NHW women and 24.2, 34.8 and 41.0%, respectively, in NHB women. Adjusting for infant sex, gestational age, maternal age, tobacco use, education, prenatal care, and Medicaid, the difference in birthweight between excessive and adequate GWG at a maternal BMI of 30 kg/m2 was 118 g (95% CI: 109, 127) in NHW women and 101 g (95% CI: 91, 111) in NHB women. Moreover, excessive versus adequate GWG conveyed similar protection from having a small for gestational age infant in NHW [OR = 0.64 (95% CI 0.61, 0.67)] and NHB women [OR = 0.68 (95% CI: 0.65, 0.72)]. In conclusion, we report a strong association between excessive GWG and higher infant birthweight across maternal BMI classes in NHW and NHB women. Given the high prevalence of excessive GWG even a small increase in birthweight may have considerable implications at the population level. DA - 2012/2/11/ PY - 2012/2/11/ DO - 10.1007/s10995-012-0950-x VL - 17 IS - 1 SP - 85-94 J2 - Matern Child Health J LA - en OP - SN - 1092-7875 1573-6628 UR - http://dx.doi.org/10.1007/s10995-012-0950-x DB - Crossref KW - Gestational weight gaink KW - Racial/ethnic health differences KW - Obesity KW - Birthweight ER - TY - JOUR TI - Preface: Cognitive engineering for next generation transportation systems AU - Kaber, David B. T2 - Human Factors and Ergonomics in Manufacturing & Service Industries DA - 2012/9// PY - 2012/9// DO - 10.1002/HFM.20505 VL - 22 IS - 5 SP - 375-377 J2 - Hum. Factors Man. LA - en OP - SN - 1090-8471 UR - http://dx.doi.org/10.1002/HFM.20505 DB - Crossref ER - TY - JOUR TI - Simulating Public Health Capacity to Measure Performance:E. coliO157 at the North Carolina State Fair AU - Winter, Sharolyn A. AU - Ivy, Julie S. AU - Horney, Jennifer A. T2 - Risk, Hazards & Crisis in Public Policy AB - Abstract Despite the investment of billions of dollars in federal funding for emergency preparedness and response initiatives, broadly accepted performance measures for determining the efficacy of these systems have yet to be established. The inability to accurately capture this information hinders the ability to measure the true degree of preparedness. The North Carolina Public Health Information Network (NC PHIN), a key component of North Carolina's public health system, has promise as a means to measure emergency preparedness and response. In this paper, we look at how NC PHIN has increased emergency preparedness and response capacity by presenting a simulation of the 2004 State Fair Escherichia coli outbreak. We found that although the capacity exists within NC PHIN to increase emergency preparedness and response, some factors limit NC PHIN's effectiveness. Our findings suggest that proper resource allocation will be necessary in order to realize the potential of NC PHIN. DA - 2012/9// PY - 2012/9// DO - 10.1002/RHC3.12 VL - 3 IS - 3 SP - 69-82 J2 - RHC3 LA - en OP - SN - 1944-4079 UR - http://dx.doi.org/10.1002/RHC3.12 DB - Crossref KW - public health KW - performance measures KW - E. coli O157 ER - TY - CONF TI - Infinite horizon periodic review perturbed demand model with lead time AU - Lavin, J.A. AU - King, R.E. AU - Vila-Parrish, A.R. AU - Warsing, D.P. AU - Ahiska, S.S. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 540-547 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900339479&partnerID=MN8TOARS ER - TY - CONF TI - An inventory model with restricted replenishment opportunities and re-estimated demand AU - Buch, N. AU - King, R.E. AU - Vila-Parrish, A.R. AU - Warsing, D.P. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 531-539 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900300196&partnerID=MN8TOARS ER - TY - CONF TI - Unreliable supplier selection with fixed costs and order constraints AU - Wang, Y. AU - Warsing, D.P. AU - King, R.E. AU - Vila-Parrish, A. AU - Sebnem Ahiska, S. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 280-289 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900342003&partnerID=MN8TOARS ER - TY - JOUR TI - Effects of etiquette strategy on human–robot interaction in a simulated medicine delivery task AU - Zhu, Biwen AU - Kaber, David T2 - Intelligent Service Robotics DA - 2012/6/16/ PY - 2012/6/16/ DO - 10.1007/S11370-012-0113-3 VL - 5 IS - 3 SP - 199-210 J2 - Intel Serv Robotics LA - en OP - SN - 1861-2776 1861-2784 UR - http://dx.doi.org/10.1007/S11370-012-0113-3 DB - Crossref KW - Human-robot etiquette KW - Patient-robot interaction KW - Medicine delivery KW - Patient compliance ER - TY - JOUR TI - Preface AU - Fang, Shu-Cherng AU - Floudas, Christodoulos A. AU - Gao, David Y. T2 - Journal of Global Optimization DA - 2012/9/12/ PY - 2012/9/12/ DO - 10.1007/S10898-012-9977-1 VL - 54 IS - 2 SP - 219-220 J2 - J Glob Optim LA - en OP - SN - 0925-5001 1573-2916 UR - http://dx.doi.org/10.1007/S10898-012-9977-1 DB - Crossref ER - TY - JOUR TI - Impact of maternal diabetes on birthweight is greater in non-Hispanic blacks than in non-Hispanic whites AU - Hunt, K. J. AU - Marlow, N. M. AU - Gebregziabher, M. AU - Ellerbe, C. N. AU - Mauldin, J. AU - Mayorga, M. E. AU - Korte, J. E. T2 - Diabetologia AB - To determine the impact of maternal diabetes during pregnancy on racial disparities in fetal growth.Using linked birth certificate, inpatient hospital and prenatal claims data we examined live singleton births of mothers resident in South Carolina who self-reported their race as non-Hispanic white (NHW; n = 140,128) or non-Hispanic black (NHB; n = 82,492) and delivered at 28-42 weeks' gestation between 2004 and 2008.Prepregnancy diabetes prevalence was higher in NHB (3.0%) than in NHW (1.7%), while the prevalence of gestational diabetes mellitus (GDM) was similar in NHB (6.1%) and NHW (6.3%). At a delivery BMI of 35 kg/m(2), GDM exposure was associated with an average birthweight only 17 g (95% CI 4, 30) higher in NHW, but 78 g (95% CI 61, 95) higher in NHB (controlling for gestational age, maternal age, infant sex and availability of information on prenatal care). Figures for prepregnancy diabetes were 58 g (95% CI 34, 81) in NHW and 60 g (95% CI 37, 84) in NHB. GDM had a greater impact on birthweight in NHB than in NHW (60 g racial difference [95% CI 39, 82]), while prepregnancy diabetes had a large but similar impact. Similarly, the RR for GDM of having a large- relative to a normal-weight-for-gestational-age infant was lower in NHW (RR 1.41 [95% CI 1.34, 1.49]) than in NHB (RR 2.24 [95% CI 2.05, 2.46]).These data suggest that the negative effects of GDM combined with obesity during pregnancy may be greater in NHB than in NHW individuals. DA - 2012/1/12/ PY - 2012/1/12/ DO - 10.1007/s00125-011-2430-z VL - 55 IS - 4 SP - 971-980 J2 - Diabetologia LA - en OP - SN - 0012-186X 1432-0428 UR - http://dx.doi.org/10.1007/s00125-011-2430-z DB - Crossref KW - Birthweight KW - Diabetes KW - Gestational diabetes mellitus KW - Non-Hispanic black KW - Non-Hispanic white KW - Pregnancy KW - Prepregnancy diabetes ER - TY - JOUR TI - Optimal dispatching strategies for emergency vehicles to increase patient survivability AU - Bandara, Damitha AU - Mayorga, Maria E. AU - McLay, Laura A. T2 - International Journal of Operational Research AB - A major focus of emergency medical service (EMS) systems is to save lives and to minimise the effect of an emergency health incident. The objective of this research is to determine how to optimally dispatch paramedic units to emergency calls to maximise patients’ survivability. We formulate the problem as Markov decision process to obtain the optimal dispatching policies. These dispatching policies are developed incorporating the degree of the urgency of the call. The optimal policy provides an ordered preference (priority) list of ambulances to dispatch. The performance of the proposed dispatching rules is evaluated in terms of patients’ survivability rather than measuring the response time thresholds, as survival probability more directly mirrors patient outcomes. Computational examples show that dispatching the closest vehicle is not always optimal and that dispatching vehicles considering the priority of the call leads to an increase in the average survival probability of patients. DA - 2012/// PY - 2012/// DO - 10.1504/ijor.2012.048867 VL - 15 IS - 2 SP - 195 J2 - IJOR LA - en OP - SN - 1745-7645 1745-7653 UR - http://dx.doi.org/10.1504/ijor.2012.048867 DB - Crossref ER - TY - JOUR TI - A dynamic programming approach to solving the assortment planning problem with multiple quality levels AU - McElreath, Mark H. AU - Mayorga, Maria E. T2 - Computers & Operations Research AB - While the assortment planning problem, in which a firm selects a set of products to offer, has been widely studied, several problem instances exist which have not yet been solved to optimality. In particular, we consider an assortment planning problem under a locational choice model for consumer choice with both vertical and horizontal differentiation. We present a combined dynamic programming/line search approach which finds an optimal solution when customer preference for the horizontal attributes are distributed according to a unimodal distribution. The dynamic program makes use of new analytical results, which show that high quality products will be distributed near the mode. This enables significant state reduction and therefore efficient solution times. Efficient computation times allow us to study the solution for a wide range of system parameters and thereby draw several managerial conclusions. DA - 2012/7// PY - 2012/7// DO - 10.1016/j.cor.2011.08.023 VL - 39 IS - 7 SP - 1521-1529 J2 - Computers & Operations Research LA - en OP - SN - 0305-0548 UR - http://dx.doi.org/10.1016/j.cor.2011.08.023 DB - Crossref KW - Assortment planning KW - Dynamic programming KW - Line search KW - Locational choice ER - TY - JOUR TI - Two-stage quadratic integer programs with stochastic right-hand sides AU - ÖzaltIn, O.Y. AU - Prokopyev, O.A. AU - Schaefer, A.J. T2 - Mathematical Programming DA - 2012/// PY - 2012/// DO - 10.1007/s10107-010-0412-4 VL - 133 IS - 1-2 SP - 121-158 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84862285520&partnerID=MN8TOARS KW - Stochastic integer programming KW - Quadratic integer programming KW - Value functions KW - Superadditive duality ER - TY - JOUR TI - Electrical conductivity of hexagonal periodic lattice structures AU - Kumar, Vikas AU - Cormier, Denis AU - Harrysson, Ola T2 - Virtual and Physical Prototyping AB - Abstract Periodic lattice structures are three-dimensional arrays of unit cells having carefully engineered geometric properties. Solid Freeform Fabrication (SFF) processes have made it possible to tailor structural, thermal, or electrical properties by varying the shape and density of the unit-cell geometry. In this paper, the electrical conductivity of a hexagonal lattice structure is analytically derived using an effective unit-cell approach. The relationship between ligament length, ligament radius, relative density and electrical conductivity has been derived. The analysis indicates that the electrical conductivity increases with relative density and is linearly dependent on relative density at low lattice densities. Conductivity measurements of Ti-6Al-4V hexagonal lattices made via the Electron Beam Melting (EBM) process over a range of relative densities from 4% to 16% were taken in order to experimentally validate the analytical models. Keywords: lattice structurecellular materialelectron beam melting DA - 2012/3// PY - 2012/3// DO - 10.1080/17452759.2012.668784 VL - 7 IS - 1 SP - 81-90 J2 - Virtual and Physical Prototyping LA - en OP - SN - 1745-2759 1745-2767 UR - http://dx.doi.org/10.1080/17452759.2012.668784 DB - Crossref KW - lattice structure KW - cellular material KW - electron beam melting ER - TY - CHAP TI - Deterministic View Selection for Data-Analysis Queries: Properties and Algorithms AU - Huang, Rong AU - Chirkova, Rada AU - Fathi, Yahya T2 - Advances in Databases and Information Systems AB - The view-selection problem is a combinatorial optimization problem that arises in the context of on-line analytical processing (OLAP) in database management systems. We pose the problem as an integer programming (IP) model, study its structural properties, and propose effective techniques for reducing the search space of views and thus the size of the corresponding IP model. We then use these results to design both exact methods and heuristic algorithms that are effective for solving relatively large realistic-size instances of the problem. PY - 2012/// DO - 10.1007/978-3-642-33074-2_15 SP - 195-208 OP - PB - Springer Berlin Heidelberg SN - 9783642330735 9783642330742 UR - http://dx.doi.org/10.1007/978-3-642-33074-2_15 DB - Crossref ER - TY - JOUR TI - Su1270 Discrete Event Simulation Modeling: A Valuable Tool to Optimize Endoscopy Unit Efficiency AU - Gellad, Ziad F. AU - Taheri, Javad AU - Burchfield, Dariele AU - Cooper, Kevin AU - Lothrop, Sarah AU - AL-Kawas, Firas H. T2 - Gastrointestinal Endoscopy AB - Increasing demand for endoscopic procedures, coupled with decreasing reimbursement, has necessitated improvement in endoscopy unit efficiency. Discrete event simulation is a modeling methodology which has been used to optimize manufacturing processes for several decades. Our aim for this pilot study was to demonstrate the value of discrete event simulation in optimizing endoscopy unit efficiency. DA - 2012/4// PY - 2012/4// DO - 10.1016/j.gie.2012.03.695 VL - 75 IS - 4 SP - AB273-AB274 J2 - Gastrointestinal Endoscopy LA - en OP - SN - 0016-5107 UR - http://dx.doi.org/10.1016/j.gie.2012.03.695 DB - Crossref ER - TY - JOUR TI - Patient-based pharmaceutical inventory management: a two-stage inventory and production model for perishable products with Markovian demand AU - Vila-Parrish, Ana R AU - Ivy, Julie S AU - King, Russell E AU - Abel, Steven R T2 - Health Systems AB - Drug shortages have increased over the past decade, tripling since 2006. Pharmacy material managers are challenged with developing inventory policies given changing demand, limited suppliers, and regulations affecting supply. Pharmaceutical inventory management and patient care are inextricably linked; suboptimal control impacts both patient treatment and the cost of care. We study a perishable inventory problem motivated by challenges in pharmaceutical management. Inpatient hospital pharmacies stock medications in two stages, raw material and finished good (e.g. intravenous). While both stages of material are perishable, the finished form is highly perishable. Pharmacy demand depends on the population and patient conditions. We use a stochastic ‘demand state’ as a surrogate for patient condition and develop a Markov decision process to determine optimal, state-dependent two-stage inventory and production policies. We define two ordering and production scenarios, prove the existence of optimal solutions for both scenarios, and apply this framework to the management of Meropenem. DA - 2012/6// PY - 2012/6// DO - 10.1057/hs.2012.2 VL - 1 IS - 1 SP - 69-83 J2 - Health Systems LA - en OP - SN - 2047-6965 2047-6973 UR - http://dx.doi.org/10.1057/hs.2012.2 DB - Crossref KW - Markov decision process KW - perishable inventory KW - pharmacy KW - medication inventory management ER - TY - JOUR TI - Estimated Number of Preterm Births and Low Birth Weight Children Born in the United States Due to Maternal Binge Drinking AU - Truong, Khoa D. AU - Reifsnider, Odette S. AU - Mayorga, Maria E. AU - Spitler, Hugh T2 - Maternal and Child Health Journal AB - The objective of this study was to estimate the aggregate burden of maternal binge drinking on preterm birth (PTB) and low birth weight (LBW) across American sociodemographic groups in 2008. To estimate the aggregate burden of maternal binge drinking on preterm birth (PTB) and low birth weight (LBW) across American sociodemographic groups in 2008. A simulation model was developed to estimate the number of PTB and LBW cases due to maternal binge drinking. Data inputs for the model included number of births and rates of preterm and LBW from the National Center for Health Statistics; female population by childbearing age groups from the U.S. Census; increased relative risks of preterm and LBW deliveries due to maternal binge drinking extracted from the literature; and adjusted prevalence of binge drinking among pregnant women estimated in a multivariate logistic regression model using Behavioral Risk Factor Surveillance System survey. The most conservative estimates attributed maternal binge drinking to 8,701 (95% CI: 7,804-9,598) PTBs (1.75% of all PTBs) and 5,627 (95% CI 5,121-6,133) LBW deliveries in 2008, with 3,708 (95% CI: 3,375-4,041) cases of both PTB and LBW. The estimated rate of PTB due to maternal binge drinking was 1.57% among all PTBs to White women, 0.69% among Black women, 3.31% among Hispanic women, and 2.35% among other races. Compared to other age groups, women ages 40-44 had the highest adjusted binge drinking rate and highest PTB rate due to maternal binge drinking (4.33%). Maternal binge drinking contributed significantly to PTB and LBW differentially across sociodemographic groups. DA - 2012/6/19/ PY - 2012/6/19/ DO - 10.1007/s10995-012-1048-1 VL - 17 IS - 4 SP - 677-688 J2 - Matern Child Health J LA - en OP - SN - 1092-7875 1573-6628 UR - http://dx.doi.org/10.1007/s10995-012-1048-1 DB - Crossref KW - Maternal binge drinking KW - Preterm birth KW - Low birth weight KW - Racial/ethnic disparities KW - Simulation ER - TY - CONF TI - A novel fabrication method for embedding metal structures into polymers for flexible electronics AU - Carrion, H. AU - Joshi, S. AU - Shirwaiker, R. AU - Fonash, S.J. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 3212-3221 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900336522&partnerID=MN8TOARS ER - TY - CONF TI - A review of emerging industrial and systems engineering trends and future directions in biomanufacturing AU - Tan, Z. AU - Shirwaiker, R.A. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 2354-2361 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900322032&partnerID=MN8TOARS ER - TY - CONF TI - A process engineering perspective of scaffold fabrication methods in regenerative medicine: A review AU - Kazemi-Tutunchi, G. AU - Wei, C. AU - Shirwaiker, R.A. AU - Dong, J. C2 - 2012/// C3 - 62nd IIE Annual Conference and Expo 2012 DA - 2012/// SP - 3096-3105 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84900330276&partnerID=MN8TOARS ER - TY - JOUR TI - Modeling the Impact of Integrating HIV and Outpatient Health Services on Patient Waiting Times in an Urban Health Clinic in Zambia AU - Deo, Sarang AU - Topp, Stephanie M. AU - Garcia, Ariel AU - Soldner, Mallory AU - Yagci, Kezban AU - Chipukuma, Julien AU - Wamulume, Chibesa S. AU - Reid, Stewart AU - Swann, Julie T2 - SSRN Electronic Journal AB - Background: Rapid scale up of HIV treatment programs in sub-Saharan Africa has refueled the long-standing health policy debate regarding the merits and drawbacks of vertical and integrated system. Recent pilots of integrating outpatient and HIV services have shown an improvement in some patient outcomes but deterioration in waiting times, which can lead to worse health outcomes in the long run. Methods: A pilot intervention involving integration of outpatient and HIV services in an urban primary care facility in Lusaka, Zambia was studied. Data on waiting time of patients during two seven-day periods before and six months after the integration were collected using a time and motion study. Statistical tests were conducted to investigate whether the two observation periods differed in operational details such as staffing, patient arrival rates, mix of patients etc. A discrete event simulation model was constructed to facilitate a fair comparison of waiting times before and after integration. The simulation model was also used to develop alternative configurations of integration and to estimate the resulting waiting times. Results: Comparison of raw data showed that waiting times increased by 32% and 36% after integration for OPD and ART patients respectively (p Conclusions: Integrating health services has the potential of reducing waiting times due to more efficient use of resources. However, one needs to ensure that other operational factors such as staff availability are not adversely affected due to integration. DA - 2012/// PY - 2012/// DO - 10.2139/ssrn.1699566 ER - TY - CHAP TI - Humanitarian Logistics AU - Çelik, Melih AU - Ergun, Özlem AU - Johnson, Ben AU - Keskinocak, Pinar AU - Lorca, Álvaro AU - Pekgün, Pelin AU - Swann, Julie T2 - 2012 TutORials in Operations Research AB - Free AccessAboutSectionsView PDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked InEmail Go to SectionFree Access HomeINFORMS TutORials in Operations ResearchNew Directions in Informatics, Optimization, Logistics, and Production Humanitarian LogisticsMelih Çelik, Özlem Ergun, Ben Johnson, Pınar Keskinocak, Álvaro Lorca, Pelin Pekgün, Julie SwannMelih Çelik, Özlem Ergun, Ben Johnson, Pınar Keskinocak, Álvaro Lorca, Pelin Pekgün, Julie SwannPublished Online:14 Oct 2014Abstract The increase in natural and man-made disasters in the recent years has highlighted challenging problems in humanitarian operations, in addition to major long-term humanitarian development challenges. Humanitarian logistics plays an important role in preparing for, responding to, and recovering from sudden-onset disasters and addressing long-term development issues. The management of humanitarian logistics operations involves many challenges such as conflicting objectives from multiple stakeholders, coordination and collaboration, high uncertainty, and scarcity of resources. In this tutorial, we provide an introduction to humanitarian logistics and its main application areas while outlining current research trends and the major challenges faced in the area today. We also present four decision aid tools addressing typical applications of humanitarian logistics: network design for donated human breast milk delivery in South Africa, port simulation and shipment scheduling for a large international agency, demand estimation and emergency procurement for CARE, and postdisaster medical response under accessibility issues. In presenting these decision aid tools, we aim to underline the differences in issues arising from sudden-onset disasters and long-term development problems, various stages of the life cycle of disasters, and different decision levels, while also pointing to general aspects in modeling humanitarian logistics problems. This publication has no references to display. Previous Back to Top Next FiguresReferencesRelatedInformationCited ByThe Nutritious Supply Chain: Optimizing Humanitarian Food AssistanceKoen Peters, Sérgio Silva,Rui Gonçalves,Mirjana Kavelj,Hein Fleuren, Dick den Hertog, Ozlem Ergun, Mallory Freeman21 June 2021 | INFORMS Journal on Optimization, Vol. 3, No. 2Harvest Hope Food Bank Optimizes Its Promotional Strategy to Raise Donations Using Integer ProgrammingSanjay L. Ahire, Pelin Pekgün16 August 2018 | INFORMS Journal on Applied Analytics, Vol. 48, No. 4Humanitarian LogisticsBahar Yetis Kara, Sinem Savaşer3 October 2017 New Directions in Informatics, Optimization, Logistics, and ProductionSeptember 2012 Article Information Metrics Downloaded 1,077 times in the past 12 months Information Published Online:October 14, 2014 Copyright © 2012, INFORMSCite asMelih ÇelikÖzlem ErgunBen JohnsonPınar KeskinocakÁlvaro LorcaPelin PekgünJulie Swann (2014) Humanitarian Logistics. INFORMS TutORials in Operations Research null(null):18-49. https://doi.org/10.1287/educ.1120.0100 Keywordshumanitarian logisticsdisaster managementlong-term developmentequitynonprofit operationsrelief distributionPDF download PY - 2012/10/1/ DO - 10.1287/educ.1120.0100 SP - 18-49 OP - PB - INFORMS SN - 9780984337835 UR - http://dx.doi.org/10.1287/educ.1120.0100 DB - Crossref ER - TY - JOUR TI - Dynamic switching times from season to single tickets in sports and entertainment AU - Duran, Serhan AU - Swann, Julie L. AU - Yakıcı, Ertan T2 - Optimization Letters DA - 2012/// PY - 2012/// DO - 10.1007/s11590-011-0361-8 VL - 6 IS - 6 SP - 1185-1206 KW - Revenue management KW - Sports and entertainment industry KW - Stopping times KW - Bundled tickets ER - TY - JOUR TI - Modeling the impact of integrating HIV and outpatient health services on patient waiting times in an urban health clinic in Zambia. AU - Deo, S AU - Topp, SM AU - Garcia, A AU - Soldner, M AU - Yagci, Sokat K AU - Chipukuma, J AU - Wamulume, CS AU - Reid, SE AU - Swann, J T2 - PloS one AB - Rapid scale up of HIV treatment programs in sub-Saharan Africa has refueled the long-standing health policy debate regarding the merits and drawbacks of vertical and integrated system. Recent pilots of integrating outpatient and HIV services have shown an improvement in some patient outcomes but deterioration in waiting times, which can lead to worse health outcomes in the long run.A pilot intervention involving integration of outpatient and HIV services in an urban primary care facility in Lusaka, Zambia was studied. Data on waiting time of patients during two seven-day periods before and six months after the integration were collected using a time and motion study. Statistical tests were conducted to investigate whether the two observation periods differed in operational details such as staffing, patient arrival rates, mix of patients etc. A discrete event simulation model was constructed to facilitate a fair comparison of waiting times before and after integration. The simulation model was also used to develop alternative configurations of integration and to estimate the resulting waiting times.Comparison of raw data showed that waiting times increased by 32% and 36% after integration for OPD and ART patients respectively (p<0.01). Using simulation modeling, we found that a large portion of this increase could be explained by changes in operational conditions before and after integration such as reduced staff availability (p<0.01) and longer breaks between consecutive patients (p<0.05). Controlling for these differences, integration of services, per se, would have resulted in a significant decrease in waiting times for OPD and a moderate decrease for HIV services.Integrating health services has the potential of reducing waiting times due to more efficient use of resources. However, one needs to ensure that other operational factors such as staff availability are not adversely affected due to integration. DA - 2012/// PY - 2012/// DO - 10.1371/journal.pone.0035479 VL - 7 IS - 4 SP - 35479 UR - http://europepmc.org/abstract/med/22545108 ER - TY - JOUR TI - The effect speed and replenishment flexibility has on overall costs of sourcing apparel products AU - Hartman, Lisa AU - Joines, Jeffrey A. AU - Thoney, Kristin A. AU - King, Russell E. T2 - Journal of the Textile Institute AB - This research investigates the sourcing of basic and seasonal garments as a function of lead time as well as the ability that providing in-season replenishment orders has on overall costs. Most sourcing decisions are made on the basis of the first cost of the garment with little regard to the potential impact of large hidden costs (i.e. lost sales, inventory costs, markdowns, etc.). A small survey administered to apparel manufacturers and retailers is used to gather perspectives on sourcing from various regions of the world. However, its primary purpose is to gather information and data to drive a variety of case studies. The Sourcing Simulator™ is used to determine the effect that lead times, forecasting error, product drift and seasonality have on retail performance (i.e. service levels, gross margins and inventory levels) for these case studies. Analysis is performed to attempt to quantify some of these hidden costs. Results show that choosing suppliers with shorter lead times provides significant advantages for basic goods as well as seasonal goods, which in some instances justify using more expensive suppliers in terms of first cost. These advantages take on the form of smaller inventory levels for achieving the same service, as well as minimizing the impact of errors in forecast and product mix for basic goods while increasing margins by using in-season replenishments for seasonal products. DA - 2012/6// PY - 2012/6// DO - 10.1080/00405000.2011.595106 VL - 103 IS - 6 SP - 604-621 J2 - Journal of The Textile Institute LA - en OP - SN - 0040-5000 1754-2340 UR - http://dx.doi.org/10.1080/00405000.2011.595106 DB - Crossref KW - supply chain KW - sourcing decision KW - inventory models KW - lead time ER - TY - JOUR TI - Literature review on superhydrophobic self-cleaning surfaces produced by electrospinning AU - Sas, Iurii AU - Gorga, Russell E. AU - Joines, Jeff A. AU - Thoney, Kristin A. T2 - JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS AB - Abstract Self‐cleaning surface is potentially a very useful addition for many commercial products due to economic, aesthetic, and environmental reasons. Super‐hydrophobic self‐cleaning, also called Lotus effect, utilizes right combination of surface chemistry and roughness to force water droplets to form high contact angle on a surface, easily roll off a surface and pick up dirt particles on its way. Electrospinning is a promising technique for creation of superhydrophobic self‐cleaning surfaces owing to a wide set of parameters that allow effectively controlling roughness of resulted webs. This article gives a brief introduction to the theory of super‐hydrophobic self‐cleaning and basic principles of the electrospinning process and reviews the scientific literature where electrospinning was used to create superhydrophobic surfaces. The article reviewed are categorized into several groups and their results are compared in terms of superhydrophobic properties. Several issues with current state of the art and highlights of important areas for future research are discussed in the conclusion. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012 DA - 2012/6/15/ PY - 2012/6/15/ DO - 10.1002/polb.23070 VL - 50 IS - 12 SP - 824-845 SN - 1099-0488 KW - biomimetic KW - electrospinning KW - fibers KW - functionalization of polymers KW - lotus effects KW - microstructure KW - nanotechnology KW - self-cleaning KW - superhydrophobic KW - surfaces KW - textiles ER - TY - JOUR TI - Assessing manual lifting tasks based on segment angle interpolations AU - Chang, C. C. AU - Xu, X. AU - Faber, G. S. AU - Kingma, I. AU - Dennerlein, J. T. T2 - Work (Reading, Mass.) DA - 2012/// PY - 2012/// VL - 41 Suppl 1 SP - 2360-2363 ER - TY - JOUR TI - Two linear regression models predicting cumulative dynamic L5/S1 joint moment during a range of lifting tasks based on static postures AU - Xu, Xu AU - Chang, Chien-Chi AU - Lu, Ming-Lun T2 - ERGONOMICS AB - Previous studies have indicated that cumulative L5/S1 joint load is a potential risk factor for low back pain. The assessment of cumulative L5/S1 joint load during a field study is challenging due to the difficulty of continuously monitoring the dynamic joint load. This study proposes two regression models predicting cumulative dynamic L5/S1 joint moment based on the static L5/S1 joint moment of a lifting task at lift-off and set-down and the lift duration. Twelve men performed lifting tasks at varying lifting ranges and asymmetric angles in a laboratory environment. The cumulative L5/S1 joint moment was calculated from continuous dynamic L5/S1 moments as the reference for comparison. The static L5/S1 joint moments at lift-off and set-down were measured for the two regression models. The prediction error of the cumulative L5/S1 joint moment was 21 ± 14 Nm × s (12% of the measured cumulative L5/S1 joint moment) and 14 ± 9 Nm × s (8%) for the first and the second models, respectively. Practitioner Summary: The proposed regression models may provide a practical approach for predicting the cumulative dynamic L5/S1 joint loading of a lifting task for field studies since it requires only the lifting duration and the static moments at the lift-off and/or set-down instants of the lift. DA - 2012/// PY - 2012/// DO - 10.1080/00140139.2012.693627 VL - 55 IS - 9 SP - 1093-1103 SN - 1366-5847 KW - manual materials handling KW - low back pain KW - cumulative L5/S1 moment KW - static moment ER - TY - JOUR TI - Transformation between different local coordinate systems of the scapula AU - Xu, Xu AU - Lin, Jia-Hua AU - Li, Kang AU - Tan, Virak T2 - JOURNAL OF BIOMECHANICS AB - The existence of multiple local coordinate systems (LCSs) for the scapula makes it difficult to compare the kinematics of the scapula across various studies and reports. This study aimed to build transformation matrices between different LCSs for the scapula and to provide the coordinates of previously measured muscles and ligaments around the scapula with respect to the International Society of Biomechanics (ISB) recommended LCS. The bony landmarks necessary for building various local coordinate systems were digitized on 13 CT scanned scapulae. The LCSs were built based on the digitized bony landmarks and then used for calculating the transformation equations. The approximate coordinates of 28 muscles and ligaments of the scapula were expressed with respect to the ISB-recommended LCS using the derived transformation equations. The results of this study may be used for the comparison of scapula kinematics data with respect to various LCSs and for building a scapula biomechanical model with respect to ISB-recommended LCS. DA - 2012/10/11/ PY - 2012/10/11/ DO - 10.1016/j.jbiomech.2012.08.021 VL - 45 IS - 15 SP - 2724-2727 SN - 0021-9290 KW - Scapula KW - Coordinate system transformation KW - Muscle and ligament parameters KW - CT scan ER - TY - JOUR TI - Estimation of 3-D peak L5/S1 joint moment during asymmetric lifting tasks with cubic spline interpolation of segment Euler angles AU - Xu, Xu AU - Chang, Chien-Chi AU - Faber, Gert S. AU - Kingma, Idsart AU - Dennerlein, Jack T. T2 - APPLIED ERGONOMICS AB - Previous research proposed a method using interpolation of the joint angles in key frames extracted from a field-survey video to estimate the dynamic L5/S1 joint loading for symmetric lifting tasks. The advantage of this method is that there is no need to use unwieldy equipment for capturing full body movement for the lifting tasks. The current research extends this method to asymmetric lifting tasks. The results indicate that 4-point cubic spline interpolation of segment Euler angles combined with a biomechanical model can provide a good estimation of 3-D peak L5/S1 joint moments for asymmetric lifting tasks. The average absolute error in the coronal, sagittal, and transverse planes with respect to the local pelvis axes was 16Nm, 22Nm, and 11Nm, respectively. It was also found that the dynamic component of the peak L5/S1 joint moment was not monotonously convergent when the number of interpolation points was increased. These results can be helpful for developing applied ergonomic field-survey tools such as video bases systems for estimating L5/S1 moments of manual materials handling tasks. DA - 2012/1// PY - 2012/1// DO - 10.1016/j.apergo.2011.04.002 VL - 43 IS - 1 SP - 115-120 SN - 1872-9126 KW - Lifting tasks KW - 3-D L5/S1 joint moments KW - Interpolation KW - Euler angles ER - TY - JOUR TI - Estimating 3-D L5/S1 Moments During Manual Lifting Using a Video Coding System: Validity and Interrater Reliability AU - Xu, Xu AU - Chang, Chien-Chi AU - Faber, Gert S. AU - Kingma, Idsart AU - Dennerlein, Jack T. T2 - HUMAN FACTORS AB - Objective: The aim of the study was to investigate the validity and interrater reliability of using a proposed video coding system to estimate the dynamical 3-D L5/S1 joint moment on the basis of four key frames from video clips of asymmetric lifting tasks. Background: L5/S1 joint loading has been widely adopted to quantify low-back loading during lifting tasks. However, the measurement of L5/S1 joint loading usually requires a laboratory environment, which cannot be applied during field surveys. Method: The validity of this system was investigated by comparing the estimated L5/S1 joint moments of various simulated lifting tasks with motion tracking system-based reference L5/S1 joint moments. Results: The comparison showed that the video coding system yielded good estimates on peak moment ( r = .91, average absolute error [AAE] = 20.3 Nm) and cumulative moment ( r = .88, AAE = 22.5 Nm·sec) of the sagittal plane. The interrater reliability of this system was assessed among 10 raters who used this system. The intraclass correlation ranged between .51 and .89 for the moments of different planes. Conclusion: The results of the validity and interrater reliability analyses showed that the proposed video coding system could provide a good estimate of total L5/S1 joint loading on the basis of side-view video clips of the simulated lifting tasks. Application: Although it was not as accurate as a motion tracking system for L5/S1 joint loading calculations, this approach can be an alternative for back load estimation for some lifting configurations when the use of motion tracking systems is not possible. DA - 2012/12// PY - 2012/12// DO - 10.1177/0018720812441945 VL - 54 IS - 6 SP - 1053-1065 SN - 0018-7208 KW - video coding KW - lifting KW - L5/S1 moment ER - TY - JOUR TI - Coordinate transformation between shoulder kinematic descriptions in the Holzbaur et al. model and ISB sequence AU - Xu, Xu AU - Lin, Jia-Hua AU - McGorry, Raymond W. T2 - JOURNAL OF BIOMECHANICS AB - Holzbaur et al. (2005) proposed a comprehensive 3-D biomechanical upper extremity model. Since then, this model has been adopted by many other studies for kinetic and kinematic analysis of the shoulder joint. Because of the 3-D anatomical structure, three angles are necessary to define or describe shoulder kinematics. In the Holzbaur et al. model, the three angles are shoulder elevation, elevation angle, and shoulder rotation. The computational implementation of the elevation angle degree of freedom is considered in a different way than described in the recommendation of the International Society of Biomechanics (ISB). This paper presents an analysis of the transformation between the coordinates of the shoulder kinematic defined in the Holzbaur et al. upper extremity model and those defined by the ISB. The results of this study could be used for comparing the coordinates between the different descriptions of the shoulder kinematics. DA - 2012/10/11/ PY - 2012/10/11/ DO - 10.1016/j.jbiomech.2012.08.018 VL - 45 IS - 15 SP - 2715-2718 SN - 1873-2380 KW - Shoulder KW - Kinematics KW - Reference frames KW - Computational KW - Biomechanical model ER - TY - JOUR TI - Effect of touch screen button size and spacing on disabled and non-disabled user touch characteristics AU - Sesto, M. E. AU - Irwin, C. B. AU - Chen, K. B. AU - Wiegmann T2 - Human Factors DA - 2012/// PY - 2012/// VL - 54 IS - 3 SP - 425-436 ER - TY - CONF TI - Effect of posture, button size and spacing on touch characteristics for disabled and non-disabled participants AU - Chourasia, A. O. AU - Chen, K. B. AU - Wiegmann, D. A. AU - Sesto, M. E. C2 - 2012/// C3 - International Conference on Applied Human Factors and Ergonomics DA - 2012/// ER - TY - JOUR TI - Development of a web-based survey tool to assess change in breast cancer (BrCa) survivor knowledge after receipt of cancer treatment summary and survivorship care plan (SCP) AU - Custer, J. L. AU - Rocque, G. B. AU - Wisinski, K. B. AU - Jones, N. R. AU - Donohue, S. AU - Koehn, T. M. AU - Champeny, T. L. AU - Terhaar, A. R. AU - Chen, K. B. AU - Peck, K. A. AU - Tun, M. T. AU - Wiegmann, D. A. AU - Sesto, M. E. AU - Tevaarwerk, A. J. T2 - Cancer Research (Chicago, Ill. Online) DA - 2012/// PY - 2012/// VL - 72 IS - 24 Suppl. SP - 2-11 ER - TY - BOOK TI - Simulation Modeling with SIMIO: A Workbook AU - Joines, J.A. AU - Roberts, S.D. DA - 2012/// PY - 2012/// ET - 2nd PB - Sewickley, PA: SIMIO LLC ER - TY - BOOK TI - Materialized views AU - Chirkova, R. AU - Yang, J. DA - 2012/// PY - 2012/// PB - Boston, [Massachusetts]: now Pub. ER - TY - BOOK TI - Engineering economic analysis AU - Newnan, D. G. AU - Eschenbach, T. G. AU - Lavelle, J. P. DA - 2012/// PY - 2012/// PB - New York: Oxford University Press ER - TY - CONF TI - Direct-deposition and multiple materials integration of tissue engineering scaffolds AU - Wei, C. AU - Sonawane, B. AU - Cai, L. AU - Wang, S. F. AU - Dong, J. Y. C2 - 2012/// C3 - Proceedings of the ASME International Mechanical Engineering Congress and Exposition 2010, vol 3, pts A and B DA - 2012/// SP - 1083-1088 ER - TY - CONF TI - Design of a high-bandwidth XY nanopositioning stage for high-throughput micro/nano manufacturing AU - Polit, S. AU - Dong, J. Y. C2 - 2012/// C3 - Proceedings of the ASME International Mechanical Engineering Congress and Exposition 2010, vol 3, pts A and B DA - 2012/// SP - 709-718 ER - TY - CONF TI - Analytical modeling and excimer laser micromachining of microchannel for medical devices development AU - Kim, E. AU - Narayan, R. J. AU - Lee, Yuan-Shin AB - In this paper, an analytical modeling of microchannel design and manufacturing with excimer laser micromachining is presented for medical devices development. Micro/Nano fabrication methods have made possible the creation of extremely tiny structures and systems which cannot be generated using traditional manufacturing processes. Current fabrication methods of microchannels generally require serial fabrication processes including a masking process. To overcome the drawbacks of current methods, we propose to use excimer laser micromachining to directly create microfluidic structures. Parametric study of laser machining was conducted before fabrication of microfluidic systems on polyethylene. An analytic modeling of the laser micromachining is presented to predict the machined microstructures and the surface finish. The liquid flow was visualized and studied using fluorescent dye and the velocity was measured to compare liquid behavior in each channel. The presented techniques can be used for the design and manufacturing of micro-scale medical devices development. C2 - 2012/// C3 - Proceedings of the ASME International Mechanical Engineering Congress and Exposition 2010, vol 3, pts A and B DA - 2012/// DO - 10.1115/imece2010-40985 SP - 1037–1047 ER - TY - CONF TI - Laser micromachining modeling and laser machined surface errors prediction for biomedical applications AU - Wongwiwat, P. AU - Narayan, R. J. AU - Lee, Yuan-Shin AB - This paper presents an analytical modeling and laser micromachining technique of microchannel and micro-structures for bio-devices manufacturing and biomedical applications. The ablation of the laser micromachining with direct-write method has been modeled and simulated for micro-channels or microstructures in bio-devices microfabrication. In this paper, the analytical model was adapted from the linear function for beam propagation in our previous research by using the Gaussian function to improve modeling accuracy. Basically, the new laser ablation model based on Gaussian distribution, beam propagation modeling and Beer’s law were used to formulate and model the laser ablation phenomenon. After the simulation with MATLAB programming, the actual experiment on laser micromachining has been conducted to compare the simulated results with the actual ones. Finally, the purposed modeling technique can be applied in the surface error analysis and biomedical applications. The example case in this paper showed how the modeling could solve the complex phenomenon of the overlapping in laser micromachining. C2 - 2012/// C3 - Proceedings of the ASME International Manufacturing Science and Engineering Conference, 2012 DA - 2012/// DO - 10.1115/msec2012-7370 SP - 59–68 ER - TY - CONF TI - A soi-mems-based single axis active probe for cellular force sensing and cell manipulation AU - Zhang, L. AU - Dong, J. Y. C2 - 2012/// C3 - Proceedings of the ASME International Mechanical Engineering Congress and Exposition (IMECE 2010), vol 10 DA - 2012/// SP - 537-542 ER - TY - CONF TI - A simulation study to reduce nurse overtime and improve patient flow time at a hospital endoscopy unit AU - Taheri, J. AU - Gellad, Z. AU - Burchfield, D. AU - Cooper, K. AB - Increasing demand for endoscopic procedures, coupled with decreasing insurance reimbursement, has necessitated improvement in endoscopy unit operational performance measures, such as increasing throughput and reducing staff overtime without an increase in patient waiting time. In pursuit of improving these measurements, maintaining the nurse-to-patient ratio requirements in the recovery area throughout the clinic's operation time is a challenging problem for endoscopy units. To maintain compliance with this ratio, patients occasionally have to be held in the procedure rooms during the clinic's peak time. On the other hand, level loading could potentially increase the amount of overtime. In this paper, we describe our efforts to use discrete event simulation to investigate the impact of several strategies to address the minimum recovery nurse requirements in the endoscopy unit of Duke University Medical Center. Our objective was to minimize patient flow times and nurse overtime while sustaining the required nurse-patient staffing ratio in recovery. C2 - 2012/// C3 - 2012 winter simulation conference (wsc) DA - 2012/// DO - 10.1109/wsc.2012.6465136 ER - TY - JOUR TI - Simulator study of driver responses to pedestrian treatments at multilane roundabouts AU - Salamati, K. AU - Schroeder, B. AU - Rouphail, N. M. AU - Cunningham, C. AU - Zhang, Y. AU - Kaber, D. T2 - Transportation Research Record DA - 2012/// PY - 2012/// IS - 2312 SP - 67-75 ER - TY - JOUR TI - A comparison of decision-maker perspectives for optimal cholesterol treatment AU - Mason, J. E. AU - Denton, B. T. T2 - IBM JOURNAL OF RESEARCH AND DEVELOPMENT AB - Medical decisions often involve tradeoff among competing criteria. For example, patients with third-party health insurance are primarily concerned about maximizing their quality-adjusted lifespan, since the majority of the cost burden typically falls on the third-party payer. On the other hand, third-party payers are incented to minimize total healthcare-related costs. Therefore, third-party payers must weigh the short-term cost of treatment against the long-term benefits of avoiding more costly health outcomes associated with disease progression and adverse events. The goal of the societal perspective is to achieve a reasonable balance among these competing criteria of quality-adjusted lifespan and costs. Treatment of diabetes provides a good example of the need to apply multicriteria decision-making models to treatment decisions. Chronic diseases such as diabetes are associated with high medical costs and a large number of available treatment options. In this paper, we use a Markov decision process (MDP) to show how decision-maker perspectives can influence medical treatment decisions related to cardiovascular risk management in patients with type 2 diabetes. We compare optimal treatment decisions from three different perspectives: societal, patient, and third-party payer. We further formulate an inverse MDP model to estimate the implied monetary value of a year of life, from the societal perspective, according to current U.S. treatment guidelines. DA - 2012/// PY - 2012/// DO - 10.1147/jrd.2012.2201849 VL - 56 IS - 5 SP - SN - 2151-8556 ER - TY - JOUR TI - A Markov Chain Framework for Cycle Time Approximation of Toolsets AU - Akhavan-Tabatabaei, Raha AU - Fathi, Yahya AU - Shanthikumar, J. George T2 - IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING AB - Cycle time is a key performance measure in semiconductor manufacturing. Currently, discrete event simulation and queueing theory are the most common approaches to estimating the cycle time of a fabrication facility. However, the performance of both approaches has been unsatisfactory due to many factors, including the inability to perform in an environment where informal and unwritten operational rules exist. Such rules create dependence between the arrival and service processes of a toolset, and, hence, render the classical queueing models inaccurate. We propose a Markov chain framework that attempts to approximate the cycle time of a toolset in the presence of informal operational rules, and we compare our approach with classical queueing models through a series of numerical examples. DA - 2012/11// PY - 2012/11// DO - 10.1109/tsm.2012.2202252 VL - 25 IS - 4 SP - 589-597 SN - 1558-2345 KW - Markov processes KW - queueing analysis KW - stochastic processes ER - TY - JOUR TI - Biodegradable Photo-Crosslinked Polymer Substrates with Concentric Microgrooves for Regulating MC3T3-E1 Cell Behavior AU - Wang, Kan AU - Cai, Lei AU - Zhang, Li AU - Dong, Jingyan AU - Wang, Shanfeng T2 - ADVANCED HEALTHCARE MATERIALS AB - Abstract Both intrinsic material properties and topographical features are critical in influencing cell‐biomaterial interactions. We present a systematic investigation of regulating mouse pre‐osteoblastic MC3T3‐E1 cell behavior on biodegradable polymer substrates with distinct mechanical properties and concentric microgrooves. The precursors for fabricating substrates used here were two poly(ϵ‐caprolactone) triacrylates (PCLTAs) synthesized from poly(ϵ‐caprolactone) triols with molecular weights of ∼7000 and ∼10000 g mol −1 . These two PCLTAs were photo‐crosslinked into PCL networks with distinct thermal, rheological, and mechanical properties at physiological temperature because of their different crystallinities and melting temperatures. Microgrooved substrates with four groove widths of 7.5, 16.1, 44.2, and 91.2 μm and three groove depths of 0.2, 1, and 10 μm were prepared through replica molding, i.e., photo‐crosslinking PCLTA on micro‐fabricated silicon wafers with pre‐designed concentric groove patterns. MC3T3‐E1 cell attachment and proliferation could be better supported by the stiffer substrates while not significantly influenced by the microgrooves. Microgroove dimensions could regulate MC3T3‐E1 cell alignment, nuclear shape and distribution, mineralization, and gene expression. Among the microgrooves with a fixed depth of 10 μm, the smallest width of 7.5 μm could align and elongate the cytoskeleton and nuclei most efficiently. Strikingly, higher mineral deposition and upregulation of osteocalcin gene expression were found in the narrower microgrooves when the groove depth was 10 μm. DA - 2012/5// PY - 2012/5// DO - 10.1002/adhm.201200030 VL - 1 IS - 3 SP - 292-301 SN - 2192-2659 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84878117340&partnerID=MN8TOARS ER - TY - JOUR TI - The nearest point problem in a polyhedral set and its extensions AU - Liu, Zhe AU - Fathi, Yahya T2 - COMPUTATIONAL OPTIMIZATION AND APPLICATIONS DA - 2012/9// PY - 2012/9// DO - 10.1007/s10589-011-9448-5 VL - 53 IS - 1 SP - 115-130 SN - 1573-2894 KW - Quadratic programming KW - Pos cone KW - Projection face KW - Active constraint ER - TY - JOUR TI - The G(t)/GI/s(t)+GI many-server fluid queue AU - Liu, Yunan AU - Whitt, Ward T2 - QUEUEING SYSTEMS AB - This paper introduces a deterministic fluid model that approximates the many-server G t /GI/s t +GI queueing model, and determines the time-dependent performance functions. The fluid model has time-varying arrival rate and service capacity, abandonment from queue, and non-exponential service and patience distributions. Two key assumptions are that: (i) the system alternates between overloaded and underloaded intervals, and (ii) the functions specifying the fluid model are suitably smooth. An algorithm is developed to calculate all performance functions. It involves the iterative solution of a fixed-point equation for the time-varying rate that fluid enters service and the solution of an ordinary differential equation for the time-varying head-of-line waiting time, during each overloaded interval. Simulations are conducted to confirm that the algorithm and the approximation are effective. DA - 2012/8// PY - 2012/8// DO - 10.1007/s11134-012-9291-0 VL - 71 IS - 4 SP - 405-444 SN - 1572-9443 KW - Queues with time-varying arrivals KW - Nonstationary queues KW - Transient behavior KW - Many-server queues KW - Deterministic fluid model KW - Customer abandonment KW - Non-Markovian queues ER - TY - JOUR TI - Simulation optimization of PSA-threshold based prostate cancer screening policies AU - Underwood, Daniel J. AU - Zhang, Jingyu AU - Denton, Brian T. AU - Shah, Nilay D. AU - Inman, Brant A. T2 - HEALTH CARE MANAGEMENT SCIENCE AB - We describe a simulation optimization method to design PSA screening policies based on expected quality adjusted life years (QALYs). Our method integrates a simulation model in a genetic algorithm which uses a probabilistic method for selection of the best policy. We present computational results about the efficiency of our algorithm. The best policy generated by our algorithm is compared to previously recommended screening policies. Using the policies determined by our model, we present evidence that patients should be screened more aggressively but for a shorter length of time than previously published guidelines recommended. DA - 2012/12// PY - 2012/12// DO - 10.1007/s10729-012-9195-x VL - 15 IS - 4 SP - 293-309 SN - 1572-9389 KW - Prostate cancer screening KW - Simulation optimization KW - Genetic algorithm KW - Ranking and selection ER - TY - JOUR TI - Radiographic Evaluation of Early Periprosthetic Femoral Bone Contrast and Prosthetic Stem Alignment after Uncemented and Cemented Total Hip Replacement in Dogs AU - Mostafa, Ayman A. AU - Drueen, Svenja AU - Nolte, Ingo AU - Wefstaedt, Patrick T2 - VETERINARY SURGERY AB - Objective To radiographically evaluate periprosthetic femoral bone contrast and assess alignment of the prosthetic stem after uncemented and cemented total hip replacement ( THR ). Study Design Prospective clinical study. Animals Dogs (n = 15). Methods Dogs were classified into uncemented (n = 8) and cemented (n = 7) THR groups. Radiographs were analyzed using image processing software to evaluate femoral bone contrast (gray scale value, GV ) for each and combined modified G ruen zone(s) immediately and 4 months after THR . Modified G ruen zones were classified into 5 zones to analyze retrospectively the regional radiographic GV of the femur around uncemented and cemented prosthetic stem. Alignment of prosthetic stem was assessed immediately and 4 months postoperatively. Variables were compared by use of 2‐tailed t‐test, with P < .05 considered significant. Results Zone 1 showed significant decrease in the mean bone GV 4 months after uncemented THR . No differences in zones 1–5 after 4 months of cemented THR . Combined zones showed significant decrease in overall mean bone GV 4 months after uncemented THR . No changes were observed 4 months after cemented THR . Number of limbs with varus‐aligned femoral stem markedly increased after 4 months of uncemented THR . Conclusions Regional bone contrast and prosthetic stem alignment vary with the design of THR . DA - 2012/1// PY - 2012/1// DO - 10.1111/j.1532-950x.2011.00931.x VL - 41 IS - 1 SP - 69-77 SN - 1532-950X ER - TY - JOUR TI - Quantitative assessment of workload and stressors in clinical radiation oncology AU - Mazur, L. M. AU - Mosaly, P. R. AU - Jackson, M. AU - Chang, S. X. AU - Burkhardt, K. D. AU - Adams, R. D. AU - Jones, E. L. AU - Hoyle, L. AU - Xu, J. AU - Rockwell, J. AU - Marks, L. B. T2 - International Journal of Radiation Oncology, Biology, Physics DA - 2012/// PY - 2012/// VL - 83 IS - 5 SP - E571-576 ER - TY - JOUR TI - Measurement and Modeling of Display Clutter in Advanced Flight Deck Technologies AU - Alexander, Amy L. AU - Kaber, David B. AU - Kim, Sang-Hwan AU - Stelzer, Emily M. AU - Kaufmann, Karl AU - Prinzel, Lawrence J., III T2 - INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY AB - Abstract Clutter is a key concern in the design of complex displays, particularly in safety-critical domains such as aviation. The objective of this research was to investigate techniques for measuring subjective perceptions of clutter and to model the predicted impacts of clutter on pilot performance within the context of advanced flight deck technologies. Six commercial pilots flew simulated approaches under varied workload conditions with low-, medium-, and high-clutter head-up displays, rating the perceived clutter and subjective mental workload associated with each display configuration. Results revealed that high-clutter displays produced elevated reports of perceived clutter and workload due to information density or redundancy, whereas low-clutter displays were perceived as less cluttered but challenging to use due to lack of relevant information typically used during flight. A multidimensional measure of clutter was found to be more sensitive to display differences than an overall perceived rating of clutter, and low-level visual display properties were successful in predicting clutter perceptions and pilot performance. Finalized products of this research could support optimized display design through the identification of clutter thresholds and the implementation of clutter alerts, decluttering mechanisms, or both, and could be used to support display certification and acquisitions processes. ACKNOWLEDGMENTS This article is based on work supported by the National Aeronautics and Space Administration (NASA) under Contract Number NNL06AA21A issued through the Integrated Intelligent Flight Deck (IIFD) project under the Aviation Safety Program. Any opinions, findings, and conclusions or recommendations expressed in this article are those of the authors and do not necessarily reflect the views of NASA. This research was conducted while Amy L. Alexander and Emily M. Stelzer were employed by Aptima, Inc., and Sang-Hwan Kim was a graduate student at North Carolina State University. We would like to thank Mr. Randy Bailey and Dr. Steve Young for committing substantial NASA Langley Research Center resources to this project; Mr. Jerry Karwac, Ms. Wei Anderson, and Mr. Dennis Frasca for providing simulation support; Mr. Mike Norman for providing pilot subject matter expertise in the implementation of the display configurations; Ms. Angela Allamandola for serving as a confederate copilot during the simulator test trials; and Mr. Theo Veil for his assistance with experiment planning and data collection and the pixel analyzer software development. Portions of this research were reported at the 53rd annual meeting of the Human Factors and Ergonomics Society, October 19–23, 2009, San Antonio, TX. DA - 2012/// PY - 2012/// DO - 10.1080/10508414.2012.718233 VL - 22 IS - 4 SP - 299-318 SN - 1050-8414 ER - TY - JOUR TI - Introduction to the special issue on optimizing risk management in services AU - Wu, Desheng Dash AU - Fang, Shu-Cherng AU - Olson, David L. AU - Birge, John R. T2 - OPTIMIZATION AB - In recent years, risk management has attracted a great deal of attention from both researchers and practitioners. Complexity and uncertainty in many practical problems require new methods and tools. Risk management can be used as a tool for greater rewards, not just for control against loss. Risks are studied from different silo disciplinary perspectives, with a discussion of how various methods and tools are used to optimize risk management. Enterprise risk management has become an important topic in today's more complex, interrelated global business environment, replete with threats from natural, political, economic and technical sources. DA - 2012/// PY - 2012/// DO - 10.1080/02331934.2012.724795 VL - 61 IS - 10 SP - 1175-1177 SN - 0233-1934 KW - risk management KW - optimization ER - TY - JOUR TI - An Accessible Cognitive Modeling Tool for Evaluation of Pilot-Automation Interaction AU - Gil, Guk-Ho AU - Kaber, David B. T2 - INTERNATIONAL JOURNAL OF AVIATION PSYCHOLOGY AB - Abstract Various cognitive modeling techniques and tools have been developed to support description and prediction of human behavior in complex systems. GOMS (Goals, Operators, Methods and Selection rules) modeling methods have been used in human–computer interaction (HCI) analysis for many years and are considered easy to learn. GOMS has several limitations, including representing only expert behavior in tasks and not supporting detailed modeling of visual and motor operations or parallel processing. Another limitation is that operation time estimates are deterministic. This research developed an enhanced GOMS language and computational cognitive modeling tool to address the existing GOMS limitations to aid cockpit automation designers in assessing the potential for automation-induced pilot performance problems. Output of the tool for a specific flight and automation use scenario was compared with experiment data for validation purposes. Results demonstrated significant correlations of model-based pilot performance and cognitive workload predictions with observations on pilots using a flight simulator. The new enhanced cognitive modeling approach is expected to provide accurate explanations and predictions of user behaviors during the design of complex systems and interfaces in various domains involving interactive task performance. ACKNOWLEDGMENTS This research was supported by NASA Ames Research Center under Grant No. NNH06ZNH001. Mike Feary was the technical monitor. A team from APTIMA Corporation, led by Paul Picciano, programmed the CDA tool prototype used in this experiment. The opinions and conclusions expressed in this article are those of the authors and do not necessarily reflect the views of NASA. DA - 2012/// PY - 2012/// DO - 10.1080/10508414.2012.718236 VL - 22 IS - 4 SP - 319-342 SN - 1532-7108 ER - TY - JOUR TI - A many-server fluid limit for the G(t)/GI/s(t) + GI queueing model experiencing periods of overloading AU - Liu, Yunan AU - Whitt, Ward T2 - OPERATIONS RESEARCH LETTERS AB - A many-server heavy-traffic functional weak law of large numbers is established for the Gt/GI/st+GI queueing model, which has customer abandonment (the +GI), time-varying arrival rate and staffing (the subscript t) and non-exponential service and patience distributions (the two GI’s). This limit provides support for a previously proposed deterministic fluid approximation, and extends a previously established limit for the special case of exponential service times. DA - 2012/9// PY - 2012/9// DO - 10.1016/j.orl.2012.05.010 VL - 40 IS - 5 SP - 307-312 SN - 1872-7468 KW - Many-server heavy-traffic limit KW - Functional weak law of large numbers KW - Queues with time-varying arrivals KW - Nonstationary queues KW - Deterministic fluid model KW - Non-Markovian queues ER - TY - JOUR TI - Photocured Biodegradable Polymer Substrates of Varying Stiffness and Microgroove Dimensions for Promoting Nerve Cell Guidance and Differentiation AU - Cai, Lei AU - Zhang, Li AU - Dong, Jingyan AU - Wang, Shanfeng T2 - LANGMUIR AB - Photocross-linkable and biodegradable polymers have great promise in fabricating nerve conduits for guiding axonal growth in peripheral nerve regeneration. Here, we photocross-linked two poly(ε-caprolactone) triacrylates (PCLTAs) with number-average molecular weights of ∼7000 and ∼10 000 g mol–1 into substrates with parallel microgrooves. Cross-linked PCLTA7k was amorphous and soft, while cross-linked PCLTA10k was semicrystalline with a stiffer surface. We employed different dimensions of interests for the parallel microgrooves, that is, groove widths of 5, 15, 45, and 90 μm and groove depths of 0.4, 1, 5, and 12 μm. The behaviors of rat Schwann cell precursor line (SpL201) cells with the glial nature and pheochromocytoma (PC12) cells with the neuronal nature were studied on these microgrooved substrates, showing distinct preference to the substrates with different mechanical properties. We found different threshold sensitivities of the two nerve cell types to topographical features when their cytoskeleton and nuclei were altered by varying the groove depth and width. Almost all of the cells were aligned in the narrowest and deepest microgrooves or around the edge of microgrooves. Oriented SpL201 cell movement had a higher motility as compared to unaligned ones. After forskolin treatment, SpL201 cells demonstrated significantly upregulated S-100 and O4 on stiffer substrates or narrower microgrooves, suggesting more differentiation toward early Schwann cells (SCs). PC12 neurites were oriented with enhanced extension in narrower microgrooves. The present results not only improve our fundamental understanding on nerve cell–substrate interactions, but also offer useful conduit materials and appropriate feature dimensions to foster guidance for axonal growth in peripheral nerve regeneration. DA - 2012/8/28/ PY - 2012/8/28/ DO - 10.1021/la302868q VL - 28 IS - 34 SP - 12557-12568 SN - 0743-7463 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000307988700018&KeyUID=WOS:000307988700018 ER - TY - JOUR TI - Optimization of Prostate Biopsy Referral Decisions AU - Zhang, Jingyu AU - Denton, Brian T. AU - Balasubramanian, Hari AU - Shah, Nilay D. AU - Inman, Brant A. T2 - M&SOM-MANUFACTURING & SERVICE OPERATIONS MANAGEMENT AB - Prostate cancer is the most common solid tumor in American men and is screened for using prostate-specific antigen (PSA) tests. We report on a nonstationary partially observable Markov decision process (POMDP) for prostate biopsy referral decisions. The core states are the patients' prostate cancer related health states, and PSA test results are the observations. Transition probabilities and rewards are inferred from the Mayo Clinic Radical Prostatectomy Registry and the medical literature. The objective of our model is to maximize expected quality-adjusted life years. We solve the POMDP model to obtain an age and belief (probability of having prostate cancer) dependent optimal biopsy referral policy. We also prove a number of structural properties including the existence of a control-limit type policy for the biopsy referral decision. Our empirical results demonstrate a nondecreasing belief threshold in age, and we provide sufficient conditions under which PSA screening should be discontinued for older patients. Finally, the benefits of screening under the optimal biopsy referral policy are estimated, and sensitivity analysis is used to prioritize the model parameters that would benefit from additional data collection. DA - 2012/// PY - 2012/// DO - 10.1287/msom.1120.0388 VL - 14 IS - 4 SP - 529-547 SN - 1526-5498 KW - partially observable Markov decision process KW - PSA screening KW - biopsy KW - control-limit policy KW - stopping time problem ER - TY - JOUR TI - Haptic User Interfaces for the Visually Impaired: Implications for Haptically Enhanced Science Learning Systems AU - Nam, Chang S. AU - Li, Yueqing AU - Yamaguchi, Takehiko AU - Smith-Jackson, Tonya L. T2 - INTERNATIONAL JOURNAL OF HUMAN-COMPUTER INTERACTION AB - The overall quality of haptic user interfaces designed to support visually impaired students' science learning through sensorial feedback was systematically studied to investigate task performance and user behavior. Fourteen 6th- to 11th-grade students with visual impairments recruited from a state-funded blind school were asked to perform three main tasks (i.e., menu selection, structure exploration, and force recognition) using haptic user interfaces and a haptic device. This study used several dependent measures that are categorized into three types of variables: (a) task performance including success rate, workload, and task completion time; (b) user behavior defined as cursor movements proportionately represented from the user's cursor positional data; and (c) user preference. Results showed that interface type has significant effects on task performance, user behavior, and user preference, with varying degree of impact to participants with severe visual impairments performing the tasks. The results of this study as well as a set of refined design guidelines and principles should provide insights to the future research of haptic user interfaces that can be used when developing haptically enhanced science learning systems for the visually impaired. DA - 2012/// PY - 2012/// DO - 10.1080/10447318.2012.661357 VL - 28 IS - 12 SP - 784-798 SN - 1532-7590 ER - TY - JOUR TI - Design, Fabrication, and Testing of a SOI-MEMS-Based Active Microprobe for Potential Cellular Force Sensing Applications AU - Zhang, Li AU - Dong, Jingyan T2 - Advances in Mechanical Engineering AB - This paper presents the design, analysis, fabrication, and characterization of an electrostatically driven single-axis active probing device for the applications of cellular force sensing and materials characterization. The active microprobe is actuated by linear comb drivers to generate the motion in the probing direction. Both actuation and sensing comb-drive structures are designed for the probing stage. The sensing comb structures enable us to sense the probe displacement when the device is actuated, which enables applications of force-balanced sensing and provides the capability of closed-loop control towards better accuracy. The designed active probing device is fabricated on a silicon-on-insulator (SOI) substrate with a 10 μm thick device layer through surface micromachining technologies and deep reactive-ion etching (DRIE) process. The handle layer beneath probe stage is etched away by DRIE process to decrease the film damping between the stage and the handle wafer thus achieving high-quality factor. The fabricated stage provides a motion range of 14 μm at actuation voltage of 140 V. The measured natural frequency of the stage is 1.5 kHz under ambient conditions. A sensitivity of 6 fF/ μm has been achieved. The proposed single-axis probe is aimed at sensing cellular force which ranges from a few nano-Newton to μN and micromanipulation applications. DA - 2012/// PY - 2012/// DO - 10.1155/2012/785798 VL - 2012 SP - 324–349 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000308153700001&KeyUID=WOS:000308153700001 ER - TY - JOUR TI - An examination of the dynamic changes in prostate-specific antigen occurring in a population-based cohort of men over time AU - Inman, B. A. AU - Zhang, J. Y. AU - Shah, N. D. AU - Denton, B. T. T2 - BJU International AB - • To determine whether prostate-specific antigen velocity (PSA-V), PSA doubling time (PSA-DT), or PSA percentage change (PSA-PC) add incremental information to PSA alone for community-based men undergoing prostate cancer (PCa) screening.• A population-based cohort of 11 872 men from Olmsted County, MN undergoing PSA screening for PCa from 1993 to 2005 was analysed for PSA, PSA-DT, PSA-PC and PSA-V and subsequent PCa. • Receiver-operating characteristics curves and logistic regression were used to calculate the area under the curve (AUC) and Aikaike's information criterion. • Reclassification analysis was performed and the net reclassification improvement and integrated discrimination improvement were measured. • The method of Begg and Greenes was used to adjust for verification bias.• The single best predictor of future PCa was PSA (AUC = 0.773) with PSA-V (AUC = 0.729) and PSA-DT/PSA-PC (AUC = 0.689) performing worse. • After age adjustment, combining PSA with PSA-V (AUC = 0.773) or PSA-DT/PSA-PC (AUC = 0.773) resulted in no better predictions than PSA alone. • Reclassification analysis showed that adding PSA-V or PSA-DT/PSA-PC to PSA did not result in a meaningful amount of reclassification.• PSA is a better predictor of future PCa than PSA-V, PSA-DT, or PSA-PC. • Adding PSA-V, PSA-DT, or PSA-PC to PSA does not result in clinically relevant improvements in the ability to predict future PCa. DA - 2012/// PY - 2012/// DO - 10.1111/j.1464-410x.2011.10925.x VL - 110 IS - 3 SP - 375-381 ER - TY - JOUR TI - Non-stochastic Ti-6Al-4V foam structures with negative Poisson's ratio AU - Yang, Li AU - Cormier, Denis AU - West, Harvey AU - Harrysson, Ola AU - Knowlson, Kyle T2 - MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING AB - This paper details the design, fabrication, and testing of non-stochastic auxetic lattice lattice structures. All Ti–6Al–4V samples were created via the Electron Beam Melting (EBM) additive manufacturing process. It was found that the Poisson's ratio values significantly influence the mechanical properties of the structures. The bending properties of the auxetic samples were significantly higher than those of currently commercialized metal foams. The compressive strength was moderately higher than available metal foams. These results suggest that metallic auxetic structures have considerable promise for use in a variety of applications in which tradeoffs between mass and mechanical properties are crucial. DA - 2012/12/15/ PY - 2012/12/15/ DO - 10.1016/j.msea.2012.08.053 VL - 558 SP - 579-585 SN - 1873-4936 KW - Cellular materials KW - Porous materials KW - Titanium alloys KW - Failure ER - TY - JOUR TI - Investigating Human Performance in a Virtual Reality Haptic Simulator as Influenced by Fidelity and System Latency AU - Kaber, David B. AU - Li, Yingjie AU - Clamann, Michael AU - Lee, Yuan-Shin T2 - IEEE TRANSACTIONS ON SYSTEMS MAN AND CYBERNETICS PART A-SYSTEMS AND HUMANS AB - The objective of this study was to demonstrate the utility of an established model of human motor behavior for assessing the fidelity of a virtual reality (VR) and haptic-based simulation for fine motor task performance. This study was also to serve as a basis for formulating general performance-based simulator-design guidelines toward balancing perceived realism with simulator limitations, such as latency resulting from graphic and haptic renderings. A low-fidelity surgical simulator was developed as an example VR for study, and user performance was tested in a simplified tissue-cutting task using a virtual scalpel. The observed aspect of the simulation included a discrete-movement task under different system-lag conditions and settings of task difficulty. Results revealed user performance in the VR to conform with Fitts' law of motor behavior and for performance to degrade with increasing task difficulty and system time lag. In general, the findings of this work support predictions on human performance under various simulator-design conditions using an established model of motor-control behavior and formulation of human-performance-based simulator-design principles. DA - 2012/11// PY - 2012/11// DO - 10.1109/tsmca.2012.2201466 VL - 42 IS - 6 SP - 1562-1566 SN - 1558-2426 KW - Haptic interfaces KW - medical simulation KW - modeling KW - virtual reality ER - TY - JOUR TI - A Conceptual Framework for Future Research on Mode of Delivery AU - Wu, Jennifer M. AU - Viswanathan, Meera AU - Ivy, Julie S. T2 - MATERNAL AND CHILD HEALTH JOURNAL DA - 2012/10// PY - 2012/10// DO - 10.1007/s10995-011-0910-x VL - 16 IS - 7 SP - 1447-1454 SN - 1092-7875 KW - Cesarean delivery on maternal request KW - Conceptual framework KW - Mode of delivery KW - Research priorities ER - TY - JOUR TI - Stabilizing Customer Abandonment in Many-Server Queues with Time-Varying Arrivals AU - Liu, Yunan AU - Whitt, Ward T2 - OPERATIONS RESEARCH AB - An algorithm is developed to determine time-dependent staffing levels to stabilize the time-dependent abandonment probabilities and expected delays at positive target values in the M t /GI/s t + GI many-server queueing model, which has a nonhomogeneous Poisson arrival process (the M t ), has general service times (the first GI), and allows customer abandonment according to a general patience distribution (the +GI). New offered-load and modified-offered-load approximations involving infinite-server models are developed for that purpose. Simulations show that the approximations are effective. A many-server heavy-traffic limit in the efficiency-driven regime shows that (i) the proposed approximations achieve the goal asymptotically as the scale increases, and (ii) it is not possible to simultaneously stabilize the mean queue length in the same asymptotic regime. DA - 2012/// PY - 2012/// DO - 10.1287/opre.1120.1104 VL - 60 IS - 6 SP - 1551-1564 SN - 0030-364X ER - TY - JOUR TI - Prevalence and associated risk factors of low-back pain in textile fishing net manufacturing AU - Keawduangdee, Petcharat AU - Puntumetakul, Rungthip AU - Chatchawan, Uraiwon AU - Kaber, David AU - Siritaratiwat, Wantana T2 - HUMAN FACTORS AND ERGONOMICS IN MANUFACTURING & SERVICE INDUSTRIES AB - Abstract This study examined the 7‐day prevalence of low‐back pain (LBP; i.e., pain within the preceding week of the survey) and identified associated factors, including working posture, for a population of fishing net assembly workers. LBP is a serious problem in manual work with high prevalence and affects worker absenteeism. A cross‐sectional survey study was conducted among textile fish net industrial workers using a structured questionnaire (hand delivered by researchers and independently completed by workers). The 7‐day prevalence of LBP in this study was 68.6% (95% confidence interval [CI]: 65 to 72%). Work factors significantly related to LBP included prolonged standing and walking. Workers 35 years old or greater were significantly more likely to experience LBP within the past 7 days preceding the survey than were those 34 years old or less (adjusted odds ratio [ORadj] = 4.9; 95% CI: 2.4 to 10.3; p = .0001). Other significant factors associated with LBP included posture position, specifically stooping (ORadj = 1.6; 95% CI: 1.0 to 2.3; p = .033), lifting (ORadj = 1.6; 95% CI: 1.1 to 2.4; p = .025), and high concentration jobs (ORadj = 1.9; 95% CI: 1.3 to 2.7; p = .001), respectively. LBP among textile fish net workers is a serious problem meriting ergonomic evaluation and design of control measures for reducing worker exposure to risk factors. Work characteristics were more significantly associated with LBP than were individual characteristics. Factories need to consider adjusting work conditions to prevent worker low‐back injuries. © 2012 Wiley Periodicals, Inc. DA - 2012/// PY - 2012/// DO - 10.1002/hfm.20375 VL - 22 IS - 6 SP - 562-570 SN - 1520-6564 KW - Low-back pain (LBP) KW - Ergonomic risk factors KW - Individual differences KW - Fishing net manufacturing ER - TY - JOUR TI - Monitoring nonlinear profiles using a wavelet-based distribution-free CUSUM chart AU - Lee, Joongsup AU - Hur, Youngmi AU - Kim, Seong-Hee AU - Wilson, James R. T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH AB - WDFTC is a wavelet-based distribution-free CUSUM chart for detecting shifts in the mean of a profile with noisy components. Exploiting a discrete wavelet transform (DWT) of the mean in-control profile, WDFTC selects a reduced-dimension vector of the associated DWT components from which the mean in-control profile can be approximated with minimal weighted relative reconstruction error. Based on randomly sampled Phase I (in-control) profiles, the covariance matrix of the corresponding reduced-dimension DWT vectors is estimated using a matrix-regularisation method; then the DWT vectors are aggregated (batched) so that the non-overlapping batch means of the reduced-dimension DWT vectors have manageable covariances. To monitor shifts in the mean profile during Phase II operation, WDFTC computes a Hotelling's T 2-type statistic from successive non-overlapping batch means and applies a CUSUM procedure to those statistics, where the associated control limits are evaluated analytically from the Phase I data. Experimentation with several normal and non-normal test processes revealed that WDFTC was competitive with existing profile-monitoring schemes. DA - 2012/// PY - 2012/// DO - 10.1080/00207543.2012.655865 VL - 50 IS - 22 SP - 6574-6594 SN - 1366-588X KW - SPC KW - quality control KW - statistical methods KW - profile KW - CUSUM chart KW - wavelet transform ER - TY - JOUR TI - Effects of modes of cockpit automation on pilot performance and workload in a next generation flight concept of operation AU - Gil, G. H. AU - Kaber, D. AU - Kaufmann, K. AU - Kim, S. H. T2 - Human Factors and Ergonomics in Manufacturing AB - Abstract The objective of this study was to compare the effects of various forms of advanced cockpit automation for flight planning on pilot performance and workload under a futuristic concept of operation. A lab experiment was conducted in which airline pilots flew simulated tailored arrivals to an airport using three modes of automation (MOAs), including a control‐display unit (CDU) to the aircraft flight management system, an enhanced CDU (CDU+), and a continuous descent approach (CDA) tool. The arrival scenario required replanning to avoid convective activity and was constrained by a minimum fuel requirement at the initial approach fix. The CDU and CDU+ modes allowed for point‐by‐point path planning or selection among multiple standard arrivals, respectively. The CDA mode completely automated the route replanning for pilots. It was expected that the higher‐level automation would significantly reduce pilot workload and improve overall flight performance. In general, results indicated that the MOAs influenced pilot performance and workload responses according to hypotheses. This study provides new knowledge about the relationship of cockpit automation and interface features with pilot performance and workload in a novel next generation–style flight concept of operation. © 2012 Wiley Periodicals, Inc. DA - 2012/// PY - 2012/// DO - 10.1002/hfm.20377 VL - 22 IS - 5 SP - 395-406 ER - TY - JOUR TI - Effects of hazard exposure and roadway complexity on young and older driver situation awareness and performance AU - Kaber, David AU - Zhang, Yu AU - Jin, Sangeun AU - Mosaly, Prithima AU - Garner, Megan T2 - TRANSPORTATION RESEARCH PART F-TRAFFIC PSYCHOLOGY AND BEHAVIOUR AB - Few previous studies of driver situation awareness (SA) have focused on behavior in hazard negotiation. The objective of this research was to assess the effect of hazard exposure on driver SA and interactions with age and roadway complexity. Ten young (18–25 yrs) and ten older (65–81 yrs) participants drove in a simulator under two levels of environment complexity (simple – rural vs. complex – city) with two types of hazard exposure (static vs. dynamic). Situation awareness was measured using real-time probes posed by a confederate passenger. Driving performance was assessed in terms of lane maintenance and speed control. Results revealed hazards to cause degradations in high level of driver SA and speed control or to trigger adaptation, and vulnerability to hazard type was dependent on driver age. Older drivers exhibited greater speed reduction in response to dynamic hazards; whereas, young driver maintained higher speed, as compared to normal driving, when confronted with static hazards. In addition, increased roadway environment complexity compounded decrements in performance caused by hazard exposure. These findings are applicable to modeling driver behavior and SA under hazardous conditions and may support the design of new in-vehicle assistive technologies for hazard avoidance. DA - 2012/9// PY - 2012/9// DO - 10.1016/j.trf.2012.06.002 VL - 15 IS - 5 SP - 600-611 SN - 1873-5517 KW - Situation awareness KW - Roadway hazards KW - Roadway complexity KW - Age ER - TY - JOUR TI - Driver performance effects of simultaneous visual and cognitive distraction and adaptation behavior AU - Kaber, David B. AU - Liang, Yulan AU - Zhang, Yu AU - Rogers, Meghan L. AU - Gangakhedkar, Shruti T2 - TRANSPORTATION RESEARCH PART F-TRAFFIC PSYCHOLOGY AND BEHAVIOUR AB - Driver distraction has become a major concern for transportation safety due to increasing use of infotainment systems in vehicles. To reduce safety risks, it is crucial to understand how fundamental aspects of distracting activities affect driver behavior at different levels of vehicle control. This study used a simulator-based experiment to assess the effects of visual, cognitive and simultaneous distraction on operational (braking, accelerating) and tactical (maneuvering) control of vehicles. Twenty drivers participated in the study and drove in lead-car following or passing scenarios under four distraction conditions: without distraction, with visual distraction, with cognitive distraction, and with simultaneous distraction. Results revealed higher perceived workload for passing than following. Simultaneous distraction was most demanding and also resulted in the greatest steering errors among distraction conditions during both driving tasks. During passing, drivers also appeared to slow down their responses to secondary distraction tasks as workload increased. Visual distraction was associated with more off-road glances (to an in-vehicle device) and resulted in high workload. Longer headway times were also observed under visual distraction, suggesting driver adaptation to the workload. Similarly, cognitive distraction also increased driver workload but this demand did not translate into steering errors as high as for visual distraction. In general, findings indicate that tactical control of a vehicle demands more workload than operational control. Visual and cognitive distractions both increase driver workload, but they influence vehicle control and gaze behavior in different ways. DA - 2012/9// PY - 2012/9// DO - 10.1016/j.trf.2012.05.004 VL - 15 IS - 5 SP - 491-501 SN - 1369-8478 KW - Visual distraction KW - Cognitive distraction KW - Operational vehicle control KW - Tactical vehicle control KW - Driving behavior ER - TY - JOUR TI - Canonical dual approach to solving the maximum cut problem AU - Wang, Zhenbo AU - Fang, Shu-Cherng AU - Gao, David Y. AU - Xing, Wenxun T2 - JOURNAL OF GLOBAL OPTIMIZATION DA - 2012/10// PY - 2012/10// DO - 10.1007/s10898-012-9881-8 VL - 54 IS - 2 SP - 341-351 SN - 1573-2916 KW - Global optimization KW - Maximum cut KW - Canonical duality KW - Perturbation method ER - TY - JOUR TI - Effects of handicraft sitting postures on lower trunk muscle fatigue AU - Areeudomwong, Pattanasin AU - Puntumetakul, Rungthip AU - Kaber, David B. AU - Wanpen, Sawitri AU - Leelayuwat, Naruemon AU - Chatchawan, Uraiwan T2 - ERGONOMICS AB - The purpose of this study was to assess trunk muscle fatigue in seated handicraft tasks using surface electromyography (sEMG) and visual analogue scale (VAS) ratings for trunk discomfort, and to assess the relationship of these responses. Twenty-three participants were randomly assigned to assumed crossed-leg and heel sitting postures for 30 min. Normalised median frequency (NMF) slopes for lumbar multifidus (LM) and internal oblique (IO) muscles and VAS ratings were recorded. Results revealed that the crossed-leg posture produced significantly steeper NMF slopes for both sides of the LM and IO muscles than heel sitting. Greater VAS ratings were found in crossed-leg sitting posture than the heel sitting posture. The NMF slopes and the VAS ratings had significant negative correlations for both postures. Findings support heel sitting in handicraft tasks over crossed-leg sitting due to greater trunk muscle fatigue and discomfort during the latter posture. Results support VAS ratings as a complementary method to sEMG for identifying trunk muscle fatigue. DA - 2012/// PY - 2012/// DO - 10.1080/00140139.2012.658086 VL - 55 IS - 6 SP - 693-703 SN - 1366-5847 KW - trunk muscle fatigue KW - body discomfort KW - surface electromyography KW - visual analogue scale KW - normalised median frequency slope ER - TY - JOUR TI - Compressive properties of Ti-6Al-4V auxetic mesh structures made by electron beam melting AU - Yang, Li AU - Harrysson, Ola AU - West, Harvey AU - Cormier, Denis T2 - ACTA MATERIALIA AB - In this current work, a Ti–6Al–4V 3-D re-entrant lattice auxetic structure is manufactured by the electron beam melting (EBM) process. Four different design configurations (two negative Poisson’s ratio values × two relative densities) were manufactured and tested under compressive stress. Two failure modes were observed whose occurrence appeared to be dependent on the ratio of vertical strut length to re-entrant strut length. A small deflection analytical model is presented that predicts yield strength and modulus for one type of design with good accuracy. Results also show that the re-entrant lattice structure possesses superior mechanical properties compared to regular foam structures. Limitations of the analytical model are also discussed. DA - 2012/5// PY - 2012/5// DO - 10.1016/j.actamat.2012.03.015 VL - 60 IS - 8 SP - 3370-3379 SN - 1873-2453 KW - Cellular solids KW - Metal foam KW - Poisson's ratio KW - Laser deposition KW - Compression test ER - TY - JOUR TI - Comparison of Body Weight Distribution, Peak Vertical Force, and Vertical Impulse as Measures of Hip Joint Pain and Efficacy of Total Hip Replacement AU - Seibert, Rachel AU - Marcellin-Little, Denis J. AU - Roe, Simon C. AU - DePuy, Venita AU - Lascelles, B. Duncan X. T2 - VETERINARY SURGERY AB - Objective To determine whether there is a difference between the ability of peak vertical force ( PVF ), vertical impulse ( VI ), and percentage body weight distribution (% BW dist ) in differentiating which leg is most affected by hip joint pain before total hip replacement ( THR ) surgery, and for measuring changes in limb use after THR surgery. Study Design Prospective clinical study. Animals Dogs (n = 47). Methods Ground reaction force ( GRF ) data were collected using a pressure‐sensitive walkway the day before THR surgery and at ∼3, 6, and 12 months postoperatively. PVF and VI expressed as a percentage of body weight (% PVF , % VI ), and % BW dist were recorded. Regression models performed separately for each outcome were used for statistical analysis. Results When comparing limb use between the affected limb ( AP ) and the nonaffected limb ( NP ) preoperatively, differences between limbs were statistically significant when evaluated using PVF ( P = .023), VI ( P = .010), and % BW dist ( P = .012). When evaluating the magnitude of absolute and percentage change difference in AP limb use preoperatively versus postoperatively, differences were statistically significant when evaluated using PVF ( P < .001 and P = .001, respectively), VI ( P = .001 and P < .001) and % BW dist ( P < .001 and P < .001). Conclusion There appeared to be no difference in the sensitivity of VI , PVF , and % BW dist for evaluating limb use before and after THR . DA - 2012/5// PY - 2012/5// DO - 10.1111/j.1532-950x.2012.00957.x VL - 41 IS - 4 SP - 443-447 SN - 0161-3499 ER - TY - JOUR TI - Tractable XML data exchange via relations AU - Chirkova, Rada AU - Libkin, Leonid AU - Reutter, Juan L. T2 - FRONTIERS OF COMPUTER SCIENCE AB - We consider data exchange for XML documents: given source and target schemas, a mapping between them, and a document conforming to the source schema, construct a target document and answer target queries in a way that is consistent with the source information. The problem has primarily been studied in the relational context, in which data-exchange systems have also been built. Since many XML documents are stored in relations, it is natural to consider using a relational system for XML data exchange. However, there is a complexity mismatch between query answering in relational and in XML data exchange. This indicates that to make the use of relational systems possible, restrictions have to be imposed on XML schemas and mappings, as well as on XML shredding schemes. We isolate a set of five requirements that must be fulfilled in order to have a faithful representation of the XML data-exchange problem by a relational translation. We then demonstrate that these requirements naturally suggest the in-lining technique for data-exchange tasks. Our key contribution is to provide shredding algorithms for schemas, documents, mappings and queries, and demonstrate that they enable us to correctly perform XML data-exchange tasks using a relational system. DA - 2012/6// PY - 2012/6// DO - 10.1007/s11704-012-2023-0 VL - 6 IS - 3 SP - 243-263 SN - 2095-2236 KW - data exchange KW - XML KW - XML shredding KW - inlining ER - TY - JOUR TI - Relationship of orthopedic examination, goniometric measurements, and radiographic signs of degenerative joint disease in cats AU - Lascelles, B. Duncan X. AU - Dong, Yaa-Hui AU - Marcellin-Little, Denis J. AU - Thomson, Andrea AU - Wheeler, Simon AU - Correa, Maria T2 - BMC VETERINARY RESEARCH AB - Available information suggests a mismatch between radiographic and orthopedic examination findings in cats with DJD. However, the extent of the discrepancy between clinical and radiographic signs of OA in companion animals has not been described in detail. This study aimed to evaluate the relationship between orthopedic examination findings, joint goniometry, and radiographic signs of DJD in 100 cats, in a prospective observational design. Cat temperament, pain response to palpation, joint crepitus, effusion and thickening were graded. Radiographs of appendicular joints and the axial skeleton were made under sedation. Joint motion was measured by use of a plastic goniometer before and after sedation. Associations between radiographic degenerative joint disease (DJD) and examination findings were assessed to determine sensitivity, specificity and likelihood estimations.Pain response to palpation was elicited in 0-67% of the joints with DJD, with a specificity ranging from 62-99%; crepitus was detected in 0-56% of the joints and its specificity varied between 87 and 99%; for effusion, values ranged between 6 and 38% (specificity, 82-100%), and thickening, 0-59% (specificity, 74-99%). Joints with DJD tended to have a decreased range of motion. The presence of pain increased the odds of having DJD in the elbow (right: 5.5; left: 4.5); the presence of pain in the lower back increased the odds of spinal DJD being present (2.97 for lumbar; 4.67 for lumbo-sacral).Radiographic DJD cannot be diagnosed with certainty using palpation or goniometry. However, negative findings tend to predict radiographically normal joints. Palpation and goniometry may be used as a tool to help to screen cats, mostly to rule out DJD. DA - 2012/1/27/ PY - 2012/1/27/ DO - 10.1186/1746-6148-8-10 VL - 8 SP - SN - 1746-6148 KW - Pain KW - Degenerative joint disease KW - Osteoarthritis KW - Feline KW - Goniometry KW - Orthopedic KW - Joint ER - TY - JOUR TI - Global optimal solutions to a class of quadrinomial minimization problems with one quadratic constraint AU - Yuan, Y. -B AU - Fang, S. -C. AU - Gao, D. Y. T2 - JOURNAL OF GLOBAL OPTIMIZATION DA - 2012/2// PY - 2012/2// DO - 10.1007/s10898-011-9658-5 VL - 52 IS - 2 SP - 195-209 SN - 1573-2916 KW - Nonconvex optimization KW - Canonical duality KW - Triality theory KW - NP-hard problem KW - Global optimization ER - TY - JOUR TI - Setup Planning Automation for Six-Axis Wire Electrical Discharge Machining AU - Yang, Zhi AU - Wysk, Richard A. AU - Joshi, Sanjay T2 - JOURNAL OF MANUFACTURING SCIENCE AND ENGINEERING-TRANSACTIONS OF THE ASME AB - A modern six-axis wire electrical discharge machining (WEDM) system is capable of producing more complex geometries than 2D, 2½D, or ruled surface parts. The rotational axis on a six-axis WEDM system allows a part to be rotated while using a cutting wire to fabricate it. However, limited automation for process planning six-axis WEDM systems requires significant time and effort must be put into process planning. Even with commercially-available computer-aided design (CAD) software, it is difficult to produce process plans for a six-axis WEDM system. Toward automatic development of process plans, a method of determining such setup plans, including the number of setup orientations and rotational axis movements, is presented in this paper. Tangent visibility analysis results presented in our prior research are used to guide the setup, and intermediate coordinate systems are defined in order to classify the tangent visibility results. A greedy algorithm is developed to determine the set of intermediate coordinates and setup orientations for six-axis WEDM. DA - 2012/4// PY - 2012/4// DO - 10.1115/1.4005801 VL - 134 IS - 2 SP - SN - 1528-8935 ER - TY - JOUR TI - An efficient model for the crosscut optimisation problem in a wood processing mill AU - Fathi, Yahya AU - Kianfar, Kiavash T2 - INTERNATIONAL JOURNAL OF PRODUCTION RESEARCH AB - We propose a dynamic programming model for the crosscut optimisation problem. This problem arises in the context of cutting lumber (rip-first) in order to obtain cubic blocks (cut-pieces) with required dimensions and surface characteristics. We propose a novel approach for matching the pattern of defects on all four surfaces of an incoming strip of wood with the surface requirements of the cut-pieces as specified in a given cut-bill, and determine an effective cutting pattern for each incoming strip accordingly. Our proposed dynamic programming model results in fast execution times as shown by the results of a computational experiment. The model is deployed in a software package that has been implemented successfully in several major rough mills. DA - 2012/// PY - 2012/// DO - 10.1080/00207543.2010.538446 VL - 50 IS - 2 SP - 485-497 SN - 0020-7543 KW - dynamic programming KW - cutting stock problem KW - cutting lumber ER - TY - JOUR TI - The influence of learning and updating speed on the growth of commercial websites AU - Wan, X. J. AU - Deng, G. S. AU - Bai, Y. AU - Xue, S. W. T2 - Physica (Hague, Netherlands). A DA - 2012/// PY - 2012/// VL - 391 IS - 15 SP - 4018-4030 ER - TY - JOUR TI - Severe motor disability affects functional cortical integration in the context of brain-computer interface (BCI) use AU - Nam, Chang S. AU - Woo, Jincheol AU - Bahn, Sangwoo T2 - ERGONOMICS AB - The purpose of this study was to investigate cortical interaction between brain regions in people with and without severe motor disability during brain–computer interface (BCI) operation through coherence analysis. Eighteen subjects, including six patients with cerebral palsy (CP) and three patients with amyotrophic lateral sclerosis (ALS), participated. The results showed (1) the existence of BCI performance difference caused by severe motor disability; (2) different coherence patterns between participants with and without severe motor disability during BCI operation and (3) effects of motor disability on cortical connections varying in the brain regions for the different frequency bands, indicating reduced cortical differentiation and specialisation. Participants with severe neuromuscular impairments, as compared with the able-bodied group, recruited more cortical regions to compensate for the difficulties caused by their motor disability, reflecting a less efficient operating strategy for the BCI task. This study demonstrated that coherence analysis can be applied to examine the ways cortical networks cooperate with each other during BCI tasks. DA - 2012/// PY - 2012/// DO - 10.1080/00140139.2011.647095 VL - 55 IS - 5 SP - 581-591 SN - 0014-0139 KW - electroencephalography KW - EEG coherence KW - motor disability KW - brain-computer interface ER - TY - JOUR TI - Optimization of PSA Screening Policies: A Comparison of the Patient and Societal Perspectives AU - Zhang, Jingyu AU - Denton, Brian T. AU - Balasubramanian, Hari AU - Shah, Nilay D. AU - Inman, Brant A. T2 - MEDICAL DECISION MAKING AB - Objective. To estimate the benefit of PSA-based screening for prostate cancer from the patient and societal perspectives. Method. A partially observable Markov decision process model was used to optimize PSA screening decisions. Age-specific prostate cancer incidence rates and the mortality rates from prostate cancer and competing causes were considered. The model trades off the potential benefit of early detection with the cost of screening and loss of patient quality of life due to screening and treatment. PSA testing and biopsy decisions are made based on the patient’s probability of having prostate cancer. Probabilities are inferred based on the patient’s complete PSA history using Bayesian updating. Data Sources. The results of all PSA tests and biopsies done in Olmsted County, Minnesota, from 1993 to 2005 (11,872 men and 50,589 PSA test results). Outcome Measures. Patients’ perspective: to maximize expected quality-adjusted life years (QALYs); societal perspective: to maximize the expected monetary value based on societal willingness to pay for QALYs and the cost of PSA testing, prostate biopsies, and treatment. Results. From the patient perspective, the optimal policy recommends stopping PSA testing and biopsy at age 76. From the societal perspective, the stopping age is 71. The expected incremental benefit of optimal screening over the traditional guideline of annual PSA screening with threshold 4.0 ng/mL for biopsy is estimated to be 0.165 QALYs per person from the patient perspective and 0.161 QALYs per person from the societal perspective. PSA screening based on traditional guidelines is found to be worse than no screening at all. Conclusions. PSA testing done with traditional guidelines underperforms and therefore underestimates the potential benefit of screening. Optimal screening guidelines differ significantly depending on the perspective of the decision maker. DA - 2012/// PY - 2012/// DO - 10.1177/0272989x11416513 VL - 32 IS - 2 SP - 337-349 SN - 1552-681X KW - prostate cancer KW - PSA KW - partially observable Markov decision process KW - patient perspective KW - societal perspective ER - TY - JOUR TI - High-precision flexible fabrication of tissue engineering scaffolds using distinct polymers AU - Wei, Chuang AU - Cai, Lei AU - Sonawane, Bhushan AU - Wang, Shanfeng AU - Dong, Jingyan T2 - Biofabrication AB - Three-dimensional porous structures using biodegradable materials with excellent biocompatibility are critically important for tissue engineering applications. We present a multi-nozzle-based versatile deposition approach to flexibly construct porous tissue engineering scaffolds using distinct polymeric biomaterials such as thermoplastic and photo-crosslinkable polymers. We first describe the development of the deposition system and fabrication of scaffolds from two types of biodegradable polymers using this system. The thermoplastic sample is semi-crystalline poly(ε-caprolactone) (PCL) that can be processed at a temperature higher than its melting point and solidifies at room temperature. The photo-crosslinkable one is polypropylene fumarate (PPF) that has to be dissolved in a reactive solvent as a resin for being cured into solid structures. Besides the direct fabrication of thermoplastic PCL scaffolds, we specifically develop a layer molding approach for the fabrication of crosslinkable polymers, which traditionally can only be fabricated by stereolithography. In this approach, a thermoplastic supporting material (paraffin wax) is first deposited to make a mold for each specific layer, and then PPF is deposited on demand to fill the mold and cured by the UV light. The supporting material can be removed to produce a porous scaffold of crosslinked PPF. Both PCL and crosslinked PPF scaffolds fabricated using the developed system have been characterized in terms of compressive mechanical properties, morphology, pore size and porosity. Mouse MC3T3-E1 pre-osteoblastic cell studies on the fabricated scaffolds have been performed to demonstrate their capability of supporting cell proliferation and ingrowth, aiming for bone tissue engineering applications. DA - 2012/// PY - 2012/// DO - 10.1088/1758-5082/4/2/025009 VL - 4 IS - 2 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000304524700010&KeyUID=WOS:000304524700010 ER - TY - JOUR TI - Brain-computer interface (BCI) and ergonomics AU - Nam, Chang S. T2 - ERGONOMICS AB - Nearly two million people in the United States – and many more worldwide – suffer from severe motor disabilities brought on by neuromuscular impairments, such as amyotrophic lateral sclerosis (ALS)... DA - 2012/// PY - 2012/// DO - 10.1080/00140139.2012.676675 VL - 55 IS - 5 SP - 513-515 SN - 1366-5847 ER - TY - JOUR TI - Acute effects of traditional Thai massage on electroencephalogram in patients with scapulocostal syndrome AU - Buttagat, Vitsarut AU - Eungpinichpong, Wichai AU - Kaber, David AU - Chatchawan, Uraiwon AU - Arayawichanon, Preeda T2 - COMPLEMENTARY THERAPIES IN MEDICINE AB - To investigate acute effects of traditional Thai massage (TTM) on brain electrical activity (electroencephalogram (EEG) signals), anxiety and pain in patients with scapulocostal syndrome (SCS). A single-blind, randomized clinical trial. The School of Physical Therapy, Faculty of Associated Medical Sciences, Khon Kaen University, Thailand. Forty patients, who were diagnosed with SCS, were randomly allocated to receive a 30-min session of either TTM or physical therapy (PT) using ultrasound therapy and hot packs. Electroencephalogram (EEG), State Anxiety Inventory (STAI), and pain intensity rating. Results showed that both TTM and PT were associated with significant decreases in anxiety and pain intensity (p < 0.01). However, there was a significantly greater reduction in anxiety and pain intensity for the TTM group when compared with the PT group. Analysis of EEG in the TTM group showed a significant increase in relaxation, manifested as an increase in delta activity (p < 0.05) and a decrease in theta, alpha and beta activity (p < 0.01). Similar changes were not found in the PT group. The EEG measures were also significantly different when compared between the groups (p < 0.01), except for delta activity (p = 0.051), indicating lower states of arousal with the TTM treatment. It is suggested that TTM provides acute neural effects that increase relaxation and decrease anxiety and pain intensity in patients with SCS. DA - 2012/8// PY - 2012/8// DO - 10.1016/j.ctim.2012.02.002 VL - 20 IS - 4 SP - 167-174 SN - 1873-6963 KW - Traditional Thai massage KW - Physical therapy KW - Scapulocostal syndrome KW - Electroencephalogram ER - TY - JOUR TI - Effect of visual displays and locations on laparoscopic surgical training task AU - Rogers, Meghan L. AU - Heath, Will B. AU - Uy, Chad C. AU - Suresh, Sameerajan AU - Kaber, David B. T2 - APPLIED ERGONOMICS AB - The number of minimally invasive surgical (MIS) procedures has substantially increased since its introduction due to health and recovery benefits for patients. However, there are potential performance issues in MIS for surgeons due to perceptual processing demands associated with supporting technologies. Monitor location has been identified as a major factor influencing performance in these types of procedures. This study examined the effect of multiple monitors on performance during a laparoscopic surgical training task (peg transfer among instruments). Twenty-four novice subjects were exposed to different monitor conditions including a default position, a biomechanically compatible position, and a position collocated with the operating surface as well as the combination of the latter two. Subjective rankings and cognitive workload were also assessed. Results revealed a significant effect of monitor position on task time when compared to subjects' baseline training task time using the default monitor setup. Collocating the monitor with the operating surface was shown to be superior in terms of task time. There were no significant differences among monitor positions in terms of perceived workload. The results of this study provide an applicable guide for the design of MIS setups in the operating room to promote surgeon performance. DA - 2012/7// PY - 2012/7// DO - 10.1016/j.apergo.2011.11.010 VL - 43 IS - 4 SP - 762-767 SN - 0003-6870 KW - Minimally invasive surgery KW - Monitor position ER - TY - JOUR TI - Comparison of infant car seat grip orientations and lift strategies AU - Clamann, Michael AU - Zhu, Biwen AU - Beaver, Leah AU - Taylor, Kinley AU - Kaber, David T2 - APPLIED ERGONOMICS AB - The rear-facing Infant Car Seat (ICS) is designed to meet federal requirements for transporting children less than 1 year old. Typical use includes transfer in and out of a vehicle, which is shown to be a difficult lift. Despite the frequency of this lift, manufacturers provide little guidance for users. Review of relevant literature suggested an ICS featuring an angled handle, promoting a neutral wrist posture, would increase grip stability and decrease lifting effort. Popular press suggested a foot-in-car stance for the ICS lift would do the same. An experiment was conducted in which wrist deviations from neutral posture were recorded along with lifting muscle activation levels (multiple flexor muscles and biceps brachii) and overall perceived exertion for straight versus a new bent handle design and conventional stance versus foot-in-car. Foot position was examined to test the recommendations in the popular press. Surprisingly, wrist deviation was not significantly affected by the new bent handle design (due to compensatory behavior with the straight handle) but was related to foot placement (p = 0.04). Results revealed the bent handle to significantly reduce flexor activation compared with the straight handle (p = 0.0003); however, the level of biceps activation increased. Biceps activation also significantly increased for foot-in-car stance (p = 0.035) but not flexor activation. In general, the bent handle enabled the user to lift the ICS with a steadier grip and less effort. DA - 2012/7// PY - 2012/7// DO - 10.1016/j.apergo.2011.10.003 VL - 43 IS - 4 SP - 650-657 SN - 0003-6870 KW - Handle design KW - Lifting task KW - Infant car seat ER - TY - JOUR TI - Randomly generating test problems for fuzzy relational equations AU - Hu, Cheng-Feng AU - Fang, Shu-Cherng T2 - FUZZY OPTIMIZATION AND DECISION MAKING DA - 2012/3// PY - 2012/3// DO - 10.1007/s10700-011-9115-4 VL - 11 IS - 1 SP - 1-28 SN - 1573-2908 KW - Fuzzy relational equations KW - Triangular norms KW - Random generator ER - TY - JOUR TI - Optimizing Statin Treatment Decisions for Diabetes Patients in the Presence of Uncertain Future Adherence AU - Mason, Jennifer E. AU - England, Darin A. AU - Denton, Brian T. AU - Smith, Steven A. AU - Kurt, Murat AU - Shah, Nilay D. T2 - MEDICAL DECISION MAKING AB - Background. Statins are an important part of the treatment plan for patients with type 2 diabetes. However, patients who are prescribed statins often take less than the prescribed amount or stop taking the drug altogether. This suboptimal adherence may decrease the benefit of statin initiation. Objective. To estimate the influence of adherence on the optimal timing of statin initiation for patients with type 2 diabetes. Method. The authors use a Markov decision process (MDP) model to optimize the treatment decision for patients with type 2 diabetes. Their model incorporates a Markov model linking adherence to treatment effectiveness and long-term health outcomes. They determine the optimal time of statin initiation that minimizes expected costs and maximizes expected quality-adjusted life years (QALYs). Results. In the long run, approximately 25% of patients remain highly adherent to statins. Based on the MDP model, generic statins lower costs in men and result in a small increase in costs in women relative to no treatment. Patients are able to noticeably increase their expected QALYs by 0.5 to 2 years depending on the level of adherence. Conclusions. Adherence-improving interventions can increase expected QALYs by as much as 1.5 years. Given suboptimal adherence to statins, it is optimal to delay the start time for statins; however, changing the start time alone does not lead to significant changes in costs or QALYs. DA - 2012/// PY - 2012/// DO - 10.1177/0272989x11404076 VL - 32 IS - 1 SP - 154-166 SN - 1552-681X KW - adherence KW - diabetes KW - statins KW - Markov decision process ER - TY - JOUR TI - CONVEX OPTIMIZATION ON MIXED DOMAINS AU - Adivar, Murat AU - Fang, Shu-Cherng T2 - JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION AB - This paper aims to study convex analysis on some “generalized domains,” in particular, the domain of the product of closed subsets of reals. We introduce the basic concepts and derive analytic properties regarding convex subsets of mixed domains and convex functions defined on convex sets in mixed domains. The results obtained may open an avenue for modeling and solving a new type of optimization problems that involve both discrete and continuous variables at the same time. DA - 2012/2// PY - 2012/2// DO - 10.3934/jimo.2012.8.189 VL - 8 IS - 1 SP - 189-227 SN - 1553-166X KW - Continuous optimization KW - convexity KW - convex optimization KW - discrete optimization KW - generalized convexity KW - subgradient KW - time scales ER - TY - JOUR TI - A TROPICAL CYCLONE-BASED METHOD FOR GLOBAL OPTIMIZATION AU - Chao, Chien-Wen AU - Fang, Shu-Cherng AU - Liao, Ching-Jong T2 - JOURNAL OF INDUSTRIAL AND MANAGEMENT OPTIMIZATION AB - This paper proposes a new heuristic, Tropical Cyclone-based Method (TCM), for solving global optimization problems with box constraints. TCM mimics the formation process of tropical cyclones in the atmosphere to move a set of sample points towards optimality. The formation of a tropical cyclone in nature is still not completely understood by people. Nevertheless, inspired by the known formation factors of a tropical cyclone, TCM is designed to seek optimal solutions by considering airflow, disturbance, and convection in order to traverse the solution space. Experimental results on some well-known nonlinear test functions are included. Compared with the well-known Electromagnetism-like Mechanism (EM), TCM is both effective and efficient for solving the reported test functions. DA - 2012/2// PY - 2012/2// DO - 10.3934/jimo.2012.8.103 VL - 8 IS - 1 SP - 103-115 SN - 1553-166X KW - Global optimization KW - tropical cyclone KW - population-based search KW - heuristics KW - soft computing. ER - TY - JOUR TI - A 2 Degree-of-Freedom SOI-MEMS Translation Stage With Closed-Loop Positioning AU - Koo, Bonjin AU - Zhang, Xuemeng AU - Dong, Jingyan AU - Salapaka, Srinivasa M. AU - Ferreira, Placid M. T2 - JOURNAL OF MICROELECTROMECHANICAL SYSTEMS AB - This paper presents the design, analysis, fabrication, and characterization of a closed-loop XY micropositioning stage. The stage design is based on a 2 degree-of-freedom parallel kinematic mechanism with linear characteristics. Integrated with sensing combs, and fabricated in SOI wafers, the design provides a promising pathway to closed-loop positioning microelectromechanical systems platform with applications in nanomanufacturing and metrology. The XY stage provides a motion range of 20 micrometers in each direction at the driving voltage of 100 V. The resonant frequency of the XY stage under ambient conditions is 600 Hz. The positioning loop is closed using a capacitance-to-voltage conversion IC and a feedback controller is used to control position with an uncertainty characterized by a standard distribution of 5.24 nm and a closed-loop bandwidth of about 30 Hz. DA - 2012/2// PY - 2012/2// DO - 10.1109/jmems.2011.2174425 VL - 21 IS - 1 SP - 13-22 SN - 1941-0158 UR - http://www.scopus.com/inward/record.url?eid=2-s2.0-84858438834&partnerID=MN8TOARS KW - Closed-loop control KW - MEMS-scale nanopositioner KW - nanopositioning KW - parallel kinematic mechanism ER - TY - JOUR TI - Effect of illness severity and comorbidity on patient safety and adverse events AU - Naessens, J. M. AU - Campbell, C. R. AU - Shah, N. AU - Berg, B. AU - Lefante, J. J. AU - Williams, A. R. AU - Culbertson, R. T2 - American Journal of Medical Quality DA - 2012/// PY - 2012/// VL - 27 IS - 1 SP - 48-57 ER - TY - JOUR TI - An Experimental Comparison of Production Planning Using Clearing Functions and Iterative Linear Programming-Simulation Algorithms AU - Kacar, Necip Baris AU - Irdem, Durmus Fatih AU - Uzsoy, Reha T2 - IEEE TRANSACTIONS ON SEMICONDUCTOR MANUFACTURING AB - We compare the performance of three algorithms for production planning with workload-dependent lead times. These include a clearing function model using two different methods for estimating the clearing functions, and two iterative algorithms that combine linear programming and simulation models. Our experimental comparison uses a simulation model of a re-entrant bottleneck system built with attributes of a real-world semiconductor fabrication environment. We vary the bottleneck utilization, demand patterns, the mean time to failure, and the mean time to repair. Results indicate that the clearing function model performs better than the iterative algorithms on the scaled-down system considered, giving less variable production plans and higher profit values. DA - 2012/1// PY - 2012/1// DO - 10.1109/tsm.2011.2176560 VL - 25 IS - 1 SP - 104-117 SN - 0894-6507 KW - Clearing function KW - linear programming (LP) KW - production planning KW - simulation KW - workload-dependent lead times ER - TY - JOUR TI - Univariate cubic L-1 interpolating splines based on the first derivative and on 5-point windows: analysis, algorithm and shape-preserving properties AU - Jin, Qingwei AU - Yu, Lu AU - Lavery, John E. AU - Fang, Shu-Cherng T2 - COMPUTATIONAL OPTIMIZATION AND APPLICATIONS DA - 2012/3// PY - 2012/3// DO - 10.1007/s10589-011-9426-y VL - 51 IS - 2 SP - 575-600 SN - 1573-2894 KW - Cubic L-1 spline KW - First-derivative-based KW - Interpolation KW - Locally calculated KW - Shape preservation ER - TY - JOUR TI - High-rate tunable ultrasonic force regulated nanomachining lithography with an atomic force microscope AU - Zhang, Li AU - Dong, Jingyan T2 - Nanotechnology AB - This paper describes a high-rate tunable nanomachining-based nanolithography technique using an atomic force microscope (AFM). Controlled vibration between the cantilever tip and the sample is introduced to increase the lithographical speed and controllability of the nanomachining process. In this approach, an ultrasonic z vibration of the sample and the resulting ultrasonic force from the nonlinear force-distance interaction between the sample and the cantilever tip are utilized to regulate fabrication depth. A high frequency in-plane circular vibration is introduced between the tip and the sample to control the width of the fabricated features, and to improve the speed of nanolithography. Features (e.g. slots) with dimensions spanning from tens of nanometers to hundreds of nanometers are fabricated in one scan. A lithography speed of tens of microns per second can be achieved, which is significantly higher than other known mechanical-modification-based nanolithography methods. The patterns, that are machined on a thin PMMA film, are transferred to silicon substrate through a reactive ion etching process, which provides a cost-effective tunable approach for the fabrication of nanostructures. DA - 2012/// PY - 2012/// DO - 10.1088/0957-4484/23/8/085303 VL - 23 IS - 8 UR - http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=ORCID&SrcApp=OrcidOrg&DestLinkType=FullRecord&DestApp=WOS_CPL&KeyUT=WOS:000300173200012&KeyUID=WOS:000300173200012 ER - TY - JOUR TI - Development and validation of a canine radius replica for mechanical testing of orthopedic implants AU - Little, Jeffrey P. AU - Horn, Timothy J. AU - Marcellin-Little, Denis J. AU - Harrysson, Ola L. A. AU - West, Harvey A., II T2 - AMERICAN JOURNAL OF VETERINARY RESEARCH AB - Abstract Objective —To design and fabricate fiberglass-reinforced composite (FRC) replicas of a canine radius and compare their mechanical properties with those of radii from dog cadavers. Sample —Replicas based on 3 FRC formulations with 33%, 50%, or 60% short-length discontinuous fiberglass by weight (7 replicas/group) and 5 radii from large (> 30-kg) dog cadavers. Procedures —Bones and FRC replicas underwent nondestructive mechanical testing including 4-point bending, axial loading, and torsion and destructive testing to failure during 4-point bending. Axial, internal and external torsional, and bending stiffnesses were calculated. Axial pullout loads for bone screws placed in the replicas and cadaveric radii were also assessed. Results —Axial, internal and external torsional, and 4-point bending stiffnesses of FRC replicas increased significantly with increasing fiberglass content. The 4-point bending stiffness of 33% and 50% FRC replicas and axial and internal torsional stiffnesses of 33% FRC replicas were equivalent to the cadaveric bone stiffnesses. Ultimate 4-point bending loads did not differ significantly between FRC replicas and bones. Ultimate screw pullout loads did not differ significantly between 33% or 50% FRC replicas and bones. Mechanical property variability (coefficient of variation) of cadaveric radii was approximately 2 to 19 times that of FRC replicas, depending on loading protocols. Conclusions and Clinical Relevance —Within the range of properties tested, FRC replicas had mechanical properties equivalent to and mechanical property variability less than those of radii from dog cadavers. Results indicated that FRC replicas may be a useful alternative to cadaveric bones for biomechanical testing of canine bone constructs. DA - 2012/1// PY - 2012/1// DO - 10.2460/ajvr.73.1.27 VL - 73 IS - 1 SP - 27-33 SN - 1943-5681 ER - TY - JOUR TI - A canonical dual approach for solving linearly constrained quadratic programs AU - Xing, Wenxun AU - Fang, Shu-Cherng AU - Sheu, Ruey-Lin AU - Wang, Ziteng T2 - EUROPEAN JOURNAL OF OPERATIONAL RESEARCH AB - This paper provides a canonical dual approach for minimizing a general quadratic function over a set of linear constraints. We first perturb the feasible domain by a quadratic constraint, and then solve a “restricted” canonical dual program of the perturbed problem at each iteration to generate a sequence of feasible solutions of the original problem. The generated sequence is proven to be convergent to a Karush–Kuhn–Tucker point with a strictly decreasing objective value. Some numerical results are provided to illustrate the proposed approach. DA - 2012/4/1/ PY - 2012/4/1/ DO - 10.1016/j.ejor.2011.09.015 VL - 218 IS - 1 SP - 21-27 SN - 1872-6860 KW - Quadratic programming KW - Global optimization KW - Canonical duality theory ER -