Informs 2015

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INFORMS Philadelphia – 2015
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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, ,
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
Neda Sakhaee, University of Auckland, 38 Princes Street,
Auckland, New Zealand,
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,
3150 Sabre Drive, Southlake, TX, 76092, United States of
America, , Chunhua Gao,
Helder Inacio
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, -
, 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,
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,
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.
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, 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,
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, , 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,
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, , 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,
Apt. E, Raleigh, NC, 27606, United States of America,
, Tiantian Nie, Shu-cherng Fang
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,
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.
POSTER SESSION