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Operations and Logistics Research Seminars

Past Operations and Logistics Division and Centre for Operations Excellence Seminars

Past OPLOG Division Seminars - September 2016 - July 2017
Past OPLOG Division and COE Seminars - September 2015 - August 2016

Past OPLOG Seminars January 2015 -  August 2015
Past OPLOG Seminars - August 2014 - December 2014
Past OPLOG Seminars September 2013 - May 2014

Past OPLOG Seminars - September 2012 - May 2013

OPLOG Division Seminars from September 2017 - ONWARDS
 



Date: Monday, February 26th, 2018

Speaker: Varun Gupta, University of Chicago Booth School of Business
Title: "Designing load balancing and admission control policies: lessons from NDS regime"
Time: 2:30PM - 3:30PM
Place: Henry Angus 969

Abstract:  We will consider two problems in control of queueing systems: (1) load balancing policies for a multi-server system, and (2) admission control into a server with state-dependent service rates. For the first, our goal is to study the performance of simple heuristics such as Join-Shortest-Queue and Join-Idle-Queue, and the effect of service distribution on the performance. For the second system, our goal is to design admission control policies tailored specifically to the service distribution. I will try to illustrate why the recently introduced  NDS (non-degenerate slowdown) scaling regime is the right regime in which to study these questions - giving non-trivial control policies, as well as insights which are robust to the scale and traffic intensity of the system.



Date
: Friday, March 2nd, 2018

Speaker: Abraham Punnen, Simon Fraser University
Title: TBA
Time: 12:30PM - 1:30PM
Place: Henry Angus 968

Abstract: TBA



Date: Monday, March 12th, 2018

Speaker: Robert Batt, Wisconsin School of Business
Title: 
"The Effects of Discrete Work Shifts on a Nonterminating Service System"
Time: 2:30PM - 3:30PM
Place: David Lam - DL 125

Abstract: Hospital emergency departments (EDs) provide around-the-clock medical care and as such are generally modeled as nonterminating queues.  However, from the care provider’s point of view, ED care is not a never-ending process, but rather occurs in discrete work shifts and may require passing unfinished work to the next care provider at the end of the shift. We use data from a large, academic medical center ED to show that the patients’ rate of service completion varies over the course of the physician shift. Further, patients that have experienced a physician handoff have a higher rate of service completion than non-handed off patients. As a result, a patient’s expected treatment time is impacted by when in the physician’s shift treatment begins. Lastly, we show that patients that have been handed off are more likely to revisit the ED within three days, suggesting that patient handoffs lower clinical quality. 

This is joint work with Diwas S. KC (Emory University), Bradley R. Staats (University of North Carolina-Chapel Hill), Brian W. Patterson (University of Wisconsin-Madison).




Date: Monday, March 19th, 2018

Speaker: Dan Adelman, University of Chicago Booth School of Business
Title: TBA
Time: 2:30PM - 3:30PM
Place: Henry Angus 968

Abstract: TBA



Date: Monday, March 26th, 2018

Speaker: Jaelynn Oh, University of Utah
Title: TBA
Time: 2:30PM - 3:30PM
Place: Henry Angus 968

Abstract: TBA



Date: Monday, April 30th, 2018

Speaker: Tava Olsen, The University of Auckland
Title:  "Modelling Contracts and Incentives in Agricultural Cooperative Supply Chains"
Time: 2:30PM - 3:30PM
Place: Henry Angus 968

Abstract: In agricultural marketing co-operatives (co-ops), a group of farmers, or growers, collaborate under a single cooperative organizational structure to process and market their products. The trade-offs faced within the supply chain are often different to those faced by traditional investor-owned firms.  For example, most co-ops pledge to take all product produced by farmers, rather than being able to place specific orders with suppliers. Further, operational and financial decisions become inseparable because capital investment decisions are linked to the co-op's economic transactions with its members. This is particularly true for so-called proportional investment co-ops, where farmers' equity is required to be in proportion to their patronage. That is, farmers who supply a greater quantity of the given product are required to supply a proportionately higher amount of equity for the co-op. Supply yield uncertainty adds another dimension to the difficulty of coordinating the supply chain. In this talk we consider contacts and incentives in the agricultural supply chain. We present two specific models. The first is a game-theoretic model when farmers' efforts lead to higher quality. The second is a Markov decision process wherein the decisions of processing quantity interact with the financial decisions of retained earnings and short term loans.



Date
: Monday, May 7th, 2018

Speaker: Jonathan Li, University of Ottawa
Title:  "Optimization for measuring risk in stochastic programs"
Time: 2:30PM - 3:30PM
Place: Henry Angus 969

Abstract: Accounting for the adverse impact of "non-average" events has become essential in many applications involving decision making under uncertainty. Its implementation through decision models, namely stochastic programs, requires careful measurement of risk that reflects one's concern about uncertain outcomes. Important theories such as convex risk measures outline conditions required for risk measurement but provide little guidance for cases not meeting the conditions. Unfortunately, such cases are more than common in real-life situations. In particular, in this talk, we study cases where the distribution required by a law invariant risk measure is not available and/or the risk preference required by a risk measure cannot be identified. We aim to provide theoretical, computational, and empirical evidence that in these cases optimization can be a powerful tool to measure risk in a systematic fashion that is hard to achieve otherwise.  Applications to operation management and finance will be presented.