INFORMS 2021 Program Book

INFORMS Anaheim 2021

TC22

2 - Optimization for Probability Estimation and Application to Network Reliability Ashish Chandra, Purdue University, West Lafayette, IN, United States, Mohit Tawarmalani We develop optimization techniques to estimate the probability of an event (E) where the optimal value of a convex program exceeds a given threshold. A particular example we consider is the network reliability problem where we determine the probability of failures which result in network utilization exceeding one. The uncertain parameters in the problem are assumed to be drawn from the vertices of a 0/1 polytope and, for the network reliability problem, model the links that fail. Our techniques rely on a new fully polynomial approximate counting and sampling algorithms to compute the probability of an event described as a union of 0/1 knapsack polytopes. TC22 CC Room 204B In Person: Learning Algorithms in Resource Allocation and Healthcare Applications General Session Chair: Pengyi Shi, Purdue University, West Lafayette, 47907, United States 1 - Near-optimal Bayesian Online Assortment of Reusable Resources Yiding Feng, Northwestern University Electrical Engineering and Computer Science, Evanston, IL, United States, Rad Niazadeh, Amin Saberi Motivated by the applications of rental services in e-commerce, we consider revenue maximization in online assortment of reusable resources for a stream of arriving consumers with different types. We design competitive online algorithms with respect to the optimum online policy in the Bayesian setting, in which types are drawn independently from known heterogeneous distributions over time. In the regime where the minimum of initial inventories c_min is large, our main result is a near-optimal 1-min(1/2,\sqrt{log(c_min)/c_min}) competitive algorithm for the general case of reusable resources. For the special case of non-reusable resources, we further show an improved near-optimal 1-1/\sqrt{c_min+3} competitive algorithm. 2 - The Role of Horizontal Physician Integration in Alternative Payment Models Christopher Chen, Indiana University Kelley School of Business, Bloomington, IN, United States, Kraig Delana We analyze the role of consolidation of physicians within physician groups on the effectiveness of Alternative Payment Models. In the context of the Comprehensive Joint Replacement (CJR) program, we examine the extent to which this consolidation, both horizontal and vertical, increases or decreases costs and performance. 3 - The Impact of Vertical Integration on Physician Behavior And Healthcare Delivery: Evidence From Gastroenterology Practices Lina Song, University College London School of Management, London, United Kingdom, Soroush Saghafian, Joseph Newhouse, Mary Beth Landrum, John Hsu The U.S. healthcare system is undergoing a substantial change, with hospitals purchasing many physician practices (“vertical integration”). Integration could improve quality by promoting care coordination, but could also worsen it by impacting the care delivery patterns. We study the impact of vertical integration on quality and spending by examining 2.6 million Medicare patient visits across 5,488 gastroenterologists. We find that integration results in increased spending and worse quality of care. In particular, physicians reduce recommended care processes (e.g., anesthesia with deep sedation) after they integrate, which results in an increase in patients’ post-procedure complications. Policymakers should carefully design the financial incentives of the integrated providers to prevent the unintended consequences of the current integration trends. TC23 CC Room 204C In Person: Towards the Future of Air Traffic Flow Management General Session Chair: Lu Dai, University of California, Berkeley 1 - Evaluation of Wind and Convective Weather Impacts on Trajectory-based Operations (TBO) Gabriele Enea, Technical Staff, MI T. Lincoln Laboratory, Lexington, MA, 02421, United States, Michael McPartland The FAA is evolving the air traffic control system from a tactical, position-based approach, to a more strategic, trajectory-based operations (TBO) approach.

Currently, TBO systems do not have appropriate information about convective weather and extreme wind conditions to continue to operate effectively under these demanding conditions. This presentation will discuss MIT Lincoln Laboratory work in building the TBO Weather Testbed to develop a roadmap of studies and enhancements necessary to support TBO under all wind and weather conditions and the vision to create weather-aware TBO automation. 2 - Requirements Consideration for Commercial Aircraft Formation Flight Safa Saber, King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia, Eric Feron Aircraft have been flying in formation for mutual benefit for about a century. The possibility of commercial aircraft formations are only now becoming a viable option due to modern flight control systems and more capable computation. At the same time, commercial aircraft formations are also becoming a valuable construct due to congested airspace and the desire for greater fuel efficiency. The realization of commercial formations requires serious consideration of aircraft deconfliction and safety during closer-in maneuvering of large aircraft. This paper introduces formation deconfliction of transport category aircraft and presents possible solutions and questions for further research. 3 - Air Travel and COVID-19 Pandemic Spread: A US Case Study Lu Dai, University of California, Berkeley, Berkeley, CA, United States Lu Dai, National Center of Excellence for Aviation Operations Research, Berkeley, CA, United States The COVID-19 pandemic has immensely caused air transportation network disruptions. In this talk, we demonstrate models to quantify the dynamics of the impact of air travel on the spread of the COVID-19 pandemic, using a wide range of datasets covering the period from March to December 2020. Our analysis is built upon the dynamic air transportation network, where the nodes are the operating airports and the links between them inferred from realized daily flight activity. We developed a novel approach to estimate the county-level daily air passenger traffic during the pandemic, and employed cross-sectional models to estimate the impacts over different periods. TC24 CC Room 205A In Person: Innovative Business Models in Supply Chain Management General Session Chair: Xiaoyang Long, University of Wisconsin-Madison, Madison, WI, 53706-1324, United States 1 - Retail Power: A Double Edged Sword for Suppliers Shuya Yin, University of California-Irvine, Paul Merage School of Business, Irvine, CA, 92697-3125, United States, Yuhong He, Saibal Ray In distribution channels, growing power of downstream firms (retailers) is a cause of both pleasure and pain for their upstream partners (suppliers). On one hand, suppliers rely on these key retailers to generate sales. On the other hand, these retailers may have the standing to negotiate vigorously on issues like sharing of channel revenues. We use an analytical model to explore how the level of product competition (whether they are differentiated or similar), the correlation between popularity of the retailers and their bargaining powers and intensity of competition from other channels shape a supplier’s perspective about retail power: specifically, her preference about the structure of downstream retail distribution channel for her own product variants. 2 - Friend or Foe: Search Engine Advertising Strategies when The widespread growth of e-commerce has resulted in proliferation of online search infomediaries (OSIs), who provide consumers with information about products and services sold by different firms (Parents), while also referring interested consumers to the Parents’ website. Very often, both Parent and OSI advertise and compete for a spot on sponsored search page on Parent’s keyword. This leads to an interesting conundrum where Parent and OSI both compete and cooperate at same time. In this unique context, how equilibrium payment and advertising strategies affect factors such as traffic quality, advertising effectiveness, leakage, and nature of contract between two firms, is this study’s focus. Contracting with an Online Search Infomediary Abhishek Roy, Temple University, Philadelphia, PA, United States, Siddharth Bhattacharya

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