2015 Informs Annual Meeting

POSTER SESSION

INFORMS Philadelphia – 2015

61 - Fast, Provable Algorithms for Isotonic Regression in All Lp-norms (to Appear At Nips 2015) Sushant Sachdeva, Postdoctoral Associate, Yale University, Yale Institute of Network Sciences, P O Box 208263, New Haven, CT, 06520, United States of America, sachdevasushant@gmail.com, Rasmus Kyng, Anup Rao Given a directed acyclic graph G, and values y on the vertices, the Isotonic Regression of y is a vector x that respects the partial ordering given by G, and minimizes ||x - y||, for a given norm. We present improved algorithms for Isotonic Regression for all weighted Lp norms, with rigorous performance guarantees. Our algorithms combine interior point methods with provable fast solvers for the associated linear systems. The algorithms are practical and lend themselves to fast implementations. 62 - Mathematical Modelling and Analysis of New Zealand Legislation Network In 2015 the concept of Legislation Network is proposed as a mathematical tool for studying the current and future status of the legislation system in European Union. Unlike perhaps the relations between documents are at least as important as the content. This type of network has some novel features which make it an excellent test case for new network science tools. 63 - Deadhead Selection Strategies for Crew Recovery Sujeevraja Sanjeevi, Senior Operations Research, Sabre Holdings, Crew recovery is the problem of minimizing the impact of a disruption to an airline by getting disrupted crews back on plan while minimizing incurred costs. Deadheads are flights that transport crew members as passengers and are a critical part of crew recovery. Consideration of all available deadheads to recovery makes problem sizes prohibitive. We present a few deadhead selection strategies that significantly improve solution quality without impacting run-time for real-world scenarios. 64 - Talk is Cheap - Action is Expensive Simone Schmid, University of Chemnitz, Huebschmanntrasse 24, Chemnitz, 09112, Germany, simone.schmid@wirtschaft.tu- chemnitz.de, Peter Pawlowsky Adequate response to uncertain and unpredictable environmental changes requires innovative, agile, and adaptive team competencies. We use an interdisciplinary approach to assess and evaluate team competencies. From theory and previous research we derive indicators and test these by training teams accordingly. Experimental groups were given theoretical and practical trainings with regard to these team competencies. Control groups acted as usual. A succeeding standardized simulation in a high fidelity simulation environment showed significant effects with regard to team performance. From these results we propose behavioral markers for team competencies that can be used to assess team performance in critical situations. 65 - Euro/Roadef Challenge Tejinder Singh, Air Liquide, 12800 W. Little York Rd, Houston, TX, United States of America, tejinder.singh@airliquide.com, Jean Andre, Michele Quattrone, Rodrigue Fokouop, Jeffrey Arbogast The French OR Society (ROADEF) along with EURO, periodically organizes an OR challenge dedicated to industrial applications. This year, Air Liquide proposes the challenge problem concerning an IRP for the bulk distribution of liquefied gases. The challenge is open to everyone and will be presented during the EURO 2015 in Glasgow, Scotland in July 2015 and the results will be announced at EURO 2016 in Poznan, Poland. Prizes totaling 20,000 Euros will be awarded to the best teams. 66 - Usability Evaluation of a Mobile App to Reduce Congestive Heart Failure (CHF) Readmissions Minal Singhee, Master’s Student, H. John Heinz III College, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA, 15213, United States of America, msinghee@andrew.cmu.edu, Daniel Gartner, Rema Padman, Jina Lee, Sriram Iyengar Congestive Heart Failure (CHF) is a major chronic condition affecting more than 5 million people in the US. CHF readmissions is one of the major contributors to the burgeoning healthcare cost. In our study, we evaluate factors associated with the usability and acceptability of a mobile application intended to reduce CHF readmissions. A fixed protocol was developed which included Think Aloud Protocol, Quiz and a Questionnaire. Qualitative and quantitative analyses were performed. Neda Sakhaee, University of Auckland, 38 Princes Street, Auckland, New Zealand, nsak206@aucklanduni.ac.nz 3150 Sabre Drive, Southlake, TX, 76092, United States of America, sujeevraja.sanjeevi@sabre.com, Chunhua Gao, Helder Inacio

67 - An Optimization Approach to Warehouse Line Striping Sudharshana Srinivasan, Research Scientist, Altria Client Services, 601 E. Jackson St., Richmond, VA, 23219, United States of America, sudharshana.srinivasan@altria.com, David Kane We present a mixed-integer programming model to optimize product storage at an industrial warehouse, while adhering to safety standards stipulated by the county and the business. The model is applied to a tobacco warehouse and the results provide a storage solution comparable to current practice with an improved operational efficiency. The model recommends more walking aisles to facilitate increased spacing and airflow around the product; both of which are valued business objectives. 68 - Testing the Applicability of Genetic Algorithms for Simulation-based Healthcare Optimization Cory Stasko, MIT, 4 Garden Court, Apt. #4, Cambridge, MA, 02138, United States of America, cstasko@mit.edu We apply genetic algorithms to three distinct cases of highly non-linear healthcare optimization problems. In the first problem, OR schedules are designed to minimize downstream bottlenecks. The second problem involves network management for an accountable care organization. The third problem involves promoting the spread of ideas among connected professionals. In each case, the objective (fitness) function is the output of a simulation, and a brute force solution search is not feasible. 69 - How Do We Capture the Potential Risk of Intravenous Drug Infusion using Alert Data? Wan-ting Su, Graduate Student, Purdue University, 3376 Peppermill Drive, West Lafayette, IN, 47906, United States of America, su33@purdue.edu, Poching Delaurentis, Mark Lehto The use of smart infusion pumps is one such mechanism in ensuring the safety of medication infusions in clinical settings. We aim to utilize the data of different alert types from the Infusion Pump Informatics system to capture averted or potential medication errors and define and determine the overall risk of potential harm within a certain period of time in a medical facility. Our analysis can be used as a measure in improving intravenous medication safety and infusion drug- delivery process. 70 - Developing Freeway Demand Estimation Alternatives with Mixed Integer Linear Programming Joseph Trask, North Carolina State University, 909 Capability Drive, Raleigh, NC, United States of America, jltrask@ncsu.edu, Behzad Aghdashi, John Baugh, Nagui Rouphail This research presents a Mixed Integer Linear Programming optimization model for traffic demand estimation based on the methodology developed in the Highway Capacity Manual (HCM). Due to a lack of uniqueness for solution demand sets, a Modeling to Generate Alternatives (MGA) approach is developed to investigate the wide ranges of optimal solution sets. These solution sets can be compared through their effects on intermediate performance measures and sensitivity analysis. 71 - Batch Testing of a Series System Tonguç ‹nlöyurt, Sabanci University, Orhanli, Tuzla, Istanbul, Turkey, tonguc@sabanciuniv.edu, Ozgur Ozluk, Rebi Daldal, Baris Selcuk, Zahed Shahmoradi We consider the problem of determining the correct value of an AND function when it is costly to learn the values of its variables, with the minimum expected cost. We refer to a subset of variables whose values can be learnt at the same time a meta-test. The cost of learning the values of the variables in a meta-test includes a fixed cost plus the costs of the tests in the meta-test. 72 - Shape-preserving L1 Spline Fits: Calculation and Capability Ziteng Wang, Department of Industrial and Systems Engineering, North Carolina State University, 3120 Walnut Creek Parkway, L1 spline fits have been developed over the past decades to approximate multi- scale data and have been shown to preserve shapes well. Local approaches are designed for efficient calculation. Quantitative measures are proposed to evaluate the shape-preserving capability of different types of L1 spline fits. 73 - Evolutionary Optimization Tools of Nanostructures for Solar Cells Baomin Wang, University of Pittsburgh, 1048 Benedum Hall 3700 O’Hara Street, Pittsburgh, PA, 15261, United States of America, baw57@pitt.edu Simulation plays a significant role in optimizing solar cell efficiency. Current used optimization is exhaust search, only feasible for small group of parameters, 3 or 4. But for 7 or 8, it takes months. In this work, we integrate genetic algorithm with FDTD methods to optimize the nanostructure. This evolutionary method can decrease the simulation time to 1/6 of original time. This work demonstrates the ability of genetic algorithm technique to quickly search through a large parameter space. Apt. E, Raleigh, NC, 27606, United States of America, zwang23@ncsu.edu, Tiantian Nie, Shu-cherng Fang

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