Informs 2015

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INFORMS Philadelphia – 2015
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SA26
3 - Learning from the Offline Trace: A Case Study of the Taxi Industry
Yingjie Zhang, Carnegie Mellon University, 5000 Forbes Avenue,
Pittsburgh, PA, 15213, United States of America,
Ramayya Krishnan,
Siyuan Liu, Beibei Li
The growth of mobile and sensor technologies leads to the digitization of
individual’s offline behavior. We instantiate our research by analyzing the
digitized taxi tails to study the impact of different type and scale of information on
driver behavior. We propose a Bayesian learning model and validate it on a
unique data set containing complete information on 10.6M trip records from
11,196 taxis in a large Asian city in 2009. We find strong heterogeneity in
individual learning behavior.
SA26
26-Room 403, Marriott
Biotechnology and Bioinformatics
Contributed Session
Chair: Kan Wang, Georgia Institute of Technology, 813 Ferst Drive NW,
Atlanta, GA, 30332, United States of America,
1 - Convex: De Novo Transcriptome Error Correction
by Convexification
Meisam Razaviyayn, Stanford University, Packard Building,
Palo Alto, CA, 94305, United States of America,
David Tse, Elizabeth Tseng
De novo RNA sequencing with long reads requires accurate denoising as the first
step. Unlike the initial combinatorial formulation, we propose an iterative convex
reformulation which leads to a parallel algorithm for joint error correction and
abundance estimation. The numerical experiments on the heart tissue PacBio
samples show that, in addition to computational gain, the proposed algorithm
results in 10% improvement in the number of denoised reads as compared to the
existing software TOFU.
2 - Collection and Distribution of Cord Blood (CB) and Stem Cells
(SC) by EU Blood Banks
Katrina Nordstrom, Professor, Aalto University School of
Chemical Technology, Department of Biotechnology, Kemistintie
1A, Espoo, 02150, Finland, ,
Ari Vepsäläinen
Novel biomedical therapies call for expanding involvement of blood banks in
collection, storage and distribution of cells. This study examines operations
involving UB and SC in several EU countries. Wide variations are evident with
major differences in amounts of cells collected and discarded. Most efficient
operators are identified by minimized unnecessary collections.
3 - An Extended Formulation of the Convex Recoloring Problem
on a Tree
Sangho Shim, Northwestern University, 2001 Sheridan Road
Suite 548, Kellogg School of Management, Evanston, IL, 60208,
United States of America, ,
Kangbok Lee, Minseok Ryu, Sunil Chopra
We introduce a strong extended formulation of the convex recoloring problem on
a tree, which has an application in analyzing a phylogenetic tree. The extended
formulation has only polynomial number of constraints, but dominates the
conventional formulation and the exponentially many valid inequalities which
are previously known. The extended formulation solves the problem instances
from at the root node of the branch-and-bound tree without
branching.
4 - Dual-material 3d Printed Metamaterials with Tunable Mechanical
Property for Patient-Specific Phantom
Kan Wang, Georgia Institute of Technology, 813 Ferst Drive NW,
Atlanta, GA, 30332, United States of America,
, Mani Vannan, Changsheng Wu,
Zhen Qian, Chuck Zhang, Ben Wang
Patient-specific phantoms have a wide range of biomedical applications. Current
3D printed phantoms can only mimic Mechanical properties of soft tissues at
small strain situations. This study investigated the feasibility of mimicking the
strain-stiffening behavior of soft tissues using dual-material 3D printed
metamaterials. Both FEA and tensile experiments indicated that those dual-
material designs were able to exhibit strain-stiffening effects. Property tuning was
also demonstrated.
SA27
27-Room 404, Marriott
Multi-objective Combinatorial Problems
Sponsor: Multiple Criteria Decision Making
Sponsored Session
Chair: Banu Lokman, Assistant Professor, Middle East Technical
University, Department of Industrial Engineering, Cankaya, Ankara,
06800, Turkey,
1 - A Line Rebalancing Problem with Disruption Cost and Production
Rate Criteria
Ece Sanci, Research Assistant, Middle East Technical University
(1100004144), ODTU Endustri Muhendisligi 325, Ankara, 06800,
Turkey, Meral Azizoglu
In this study, we consider a line rebalancing problem with two objectives. We
assume that there is an initial set of assignments and a disruption on one or more
workstations that could alter the initial assignments. Our stability objective is to
minimize the disruption cost which is defined as the weighted distance between
the original and new workstations. Our efficiency objective is to maximize the
production rate. We develop some exact and heuristic procedures and report on
the results.
2 - Optimizing a Linear Function over the Nondominated Set of
Multi-objective Optimization Problems
Banu Lokman, Assistant Professor, Middle East Technical
University, Department of Industrial Engineering, Cankaya,
Ankara, 06800, Turkey,
We present an algorithm to optimize a linear function over the nondominated set
of multi-objective optimization problems. The algorithm iteratively generates
nondominated points and converges to the optimal solution. We also develop a
variation of this algorithm to approximate the optimal point with a desired level
of accuracy. We conduct experiments on multi-objective combinatorial
optimization problems and show that the algorithm works well.
3 - Representative Nondominated Sets in Multi-objective
Integer Programs
Gokhan Ceyhan, Middle East Technical University,
Department of Industrial Engineering, Ankara, 06800, Turkey,
, Banu Lokman, Murat Koksalan
We develop an algorithm to generate a representative nondominated set for
multi-objective integer programs. We define a density based representation
measure that evaluates the representativeness of a nondominated set considering
the estimated regional densities of the nondominated frontier. We also develop a
web application that is available to researchers to generate all or a representative
subset of nondominated points.
4 - Iterative Method for Finding Pareto-dominant Shift Schedules for
a Pediatric Emergency Department
Young-chae Hong, University of Michigan, 1205 Beal Avenue,
Ann Arbor, MI, 48109, United States of America,
, Amy Cohn
Building resident shift schedules for the U-M Pediatric Emergency Department is
a multi-objective combinatorial problem. Chiefs cannot provide a single objective
function or weights to trade off metrics of patient safety, educational training
requirements, and resident satisfaction. We have developed an algorithm for
generating Pareto-dominant schedules to reduce the solution space for Chief
Residents to review and to help elicit their preferences.
SA28
28-Room 405, Marriott
Combinatorial Auctions
Cluster: Auctions
Invited Session
Chair: Richard Steinberg, Chair In Operations Research, London School
of Economics, Department of Management, NAB 3.08, Houghton
Street, London, WC2A 2AE, United Kingdom,
1 - The Performance of Deferred-acceptance Auctions
Vasilis Gkatzelis, Stanford University, 474 Gates Building,
353 Serra Mall, Stanford, CA, 94305, United States of America,
, Paul Duetting, Tim Roughgarden
Milgrom and Segal recently introduced deferred-acceptance auctions and proved
that they satisfy a remarkable list of incentive guarantees. We study these
auctions through the lens of two canonical welfare-maximization problems. For
knapsack auctions, we show a strong separation between deferred-acceptance
mechanisms and arbitrary strategyproof mechanisms. For single-minded
combinatorial auctions, we design novel deferred-acceptance mechanisms with
near-optimal approximation guarantees.