2015 Informs Annual Meeting

MA10

INFORMS Philadelphia – 2015

MA11 11-Franklin 1, Marriott Convexification Techniques in Mixed-Integer Programming Sponsor: Optimization/Integer and Discrete Optimization Sponsored Session Chair: Sercan Yildiz, PhD Student, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, United States of America, syildiz@andrew.cmu.edu 1 - Sparce Cuts for Sparse Integer Programs Qianyi Wang, Georgia Institute of Technology, 755 Ferst Drive, In this talk, we present an analysis of the quality of sparse cuts for IPs with sparse formulations. In order to accomplish this analysis, we define a notion of an induced graph based on the constraint matrix. Then, we are able to relate the strength of sparse cutting-planes to graph-theoretic parameters of the induced graph. 2 - Envelopes of Bilinear Functions over Polytopes with Application to Network Interdiction Danial Davarnia, University of Florida, 303 Weil Hall, Gainesville, FL, United States of America, d.davarnia@ufl.edu, Mohit Tawarmalani, Jean-philippe P Richard We present a convexification technique to obtain, in the space of their defining variables, a linear description of the convex hull of graphs of bilinear functions over the Cartesian product of a general polytope and a simplex. We apply this procedure to study envelopes of various bilinear functions over certain polytopes. For network interdiction, our procedure yields an improved set of linearization constraints for bilinear objective terms that is cognizant of paths and cycles in the network. 3 - Convexification Techniques for Disjunctive Conic Sets Sercan Yildiz, PhD Student, Carnegie Mellon University, 5000 Forbes Ave, Pittsburgh, PA, 15213, United States of America, syildiz@andrew.cmu.edu, Fatma Kilinc Karzan We study the convex hull of disjunctions applied to a set defined as the intersection of a cone with an affine subspace. The resulting nonconvex sets are of fundamental importance in mixed-integer conic programming where they are used to derive valid inequalities. We identify and study the cases where a single convex inequality is sufficient to describe the convex hull and where this inequality can equivalently be expressed in an appropriate conic form. 4 - How to Convexify the Intersection of a Second Order Cone and a Nonconvex Quadratic Samuel Burer, Professor, University of Iowa, S346 Pappajohn Business Building, Iowa City, IA, 52242-1994, United States of America, samuel-burer@uiowa.edu, Fatma Kilinc Karzan We study how to convexify the intersection of a second-order cone and a nonconvex quadratic. Under several easy-to-verify conditions, we derive a simple, computable convex relaxation. Under further conditions, we prove that this relaxation captures precisely the corresponding convex hull. Our approach unifies and extends previous results, and we illustrate its applicability and generality with many examples. MA13 13-Franklin 3, Marriott Distributionally Robust Optimization Sponsor: Optimization/Optimization Under Uncertainty Sponsored Session Chair: Karthik Natarajan, Singapore University of Technology and Design, Singapore, Singapore, 487372, Singapore, karthik_natarajan@sutd.edu.sg 1 - Robust Optimization using Inconsistent Overlapping Marginals Anulekha Dhara, Postdoctoral Fellow, Singapore University of Technology and Design, 8 Somapah Road, Singapore, 487372, Singapore, anulekha@sutd.edu.sg, Karthik Natarajan In this paper, we consider a robust linear optimisation problem with random objective coefficients belonging to a Frechet class of distributions with inconsistent overlapping marginal. For this class of problem the goal is to find the tightest possible bound on the expected optimal value. To solve this problem we apply the notion of closest consistent marginal to obtain an approximate upper bound. NW, Atlanta, GA, 30332, United States of America, crown200x@gmail.com, Marco Molinaro, Santanu Dey

3 - Politics as an Impediment to Technology Strategy Implementation Marc Finkelstein, IE Business School, 52 Lawrence Ave West, Toronto, ON, M5M1A4, Canada, marcfinkelstein@gmail.com Organizations expend significant resources to develop a technology strategy, yet too often fail to accomplish it. They commonly perceive the failure to stem from a lack of resources and capabilities, yet exploratory research suggests that organizational politics are significantly more impactful. Research will outline the types of political maneuvering exhibited and how it is impactful to the achievement of the technology strategy.

MA10 10-Room 310, Marriott Economics of Digital Channels

Sponsor: E-Business Sponsored Session Chair: Yi-Chun (Chad) Ho, Assistant Professor, George Washington University, 2201 G Street NW, Washington, DC, 20052, United States of America, chadho@gwu.edu 1 - Loyalty Program: The Dilemma of Shipping Fee Xue Tan, University of Washington, 4747 30th Ave NE J171, Seattle, WA, 98105, United States of America, xuetan@uw.edu, Yi-chun (chad) Ho, Yong Tan Loyalty programs that offer one year of free shipping after consumers prepay a membership fee has become prevalent in recent years. This paper studies the mechanism of membership free shipping and compare it with contingent free shipping which waives the shipping fee when the order size reaches a threshold in a game theoretical setting. By changing the speed consumers receive their products, membership free shipping changes the product value. 2 - Help Doesn’t Help: A Partially Ordinal Discrete Choice Model on Review with Review in Review Jinyang Zheng, PhD Student, University of Washington, Mackenzie Hall (MKZ), Room 342, University of Washington, Seattle, WA, 98105, United States of America, zhengjy@uw.edu, Yong Tan, Guopeng Yin We investigate the objectivity of content on review platform with review in review function. By applying a partially ordinal discrete choice model, our research identifies the social capital maximization behavior when user gives rating. We find that rating giving distribution is generated by a mixed distribution of quality driven incentives and expected RIR performance driven incentives, which indicates a consequence of less objectivity of reviewers and less variety of the system. 3 - Corporate Information Disclosure: Social Media Vs. Investor Website Behnaz Bojd, University of Washington, Seattle WA, United States of America, behnaz@uw.edu, Yong Tan, Qixing Qu Traditionally, investors’ had access to key information only through the company’s websites. Nowadays, companies can also use social media platforms such as Twitter and Facebook, to release information and communicate with the market and shareholders. In this study we compare the nature of information disseminated on each channel and estimate their effectiveness on market behavior. 4 - Incentive Pricing and Quality Screening in Two-sided Markets: The Case of Zocdoc.com Yuan Jin, University of Connecticut, School of Business, OPIM, 2100 Hillside Road Unit 1041, Storrs, CT, 06269, United States of America, yuan.jin@business.uconn.edu Patients and doctors can schedule appointments on an online two-sided market platform, ZocDoc.com. ZocDoc’s profits depend on its doctors’ market quantity, and this quantity is associated with patients’ market quantity, which is in turn determined by doctors’ market quantity and quality. In this paper, I study the effect of pricing in ZocDoc’s case, and conclude that the addition of monetary incentives for high-quality doctors can improve both profits and overall doctor quality.

148