Sunday

SA59
■ SA59
59- Phoenix West- Hyatt
Many-server Queues: Approximations and Control
Sponsor: Applied Probability
Sponsored Session
Chair: Itai Gurvich, Northwestern University - Kellogg School of
Management, Evanston, IL, United States of America,
i-gurvich@kellogg.northwestern.edu
1 - Impatience Differentiation in Large-scale Service Systems with
Customer Reentrance
Guodong Pang, Assistant Professor, Pennsylvania State University,
University Park, PA, United States of America, gup3@engr.psu.edu,
Weining Kang
We consider large-scale service systems where customers need to reenter the
system to fulfill their further service requests and the reentry may happen after
some random delay time. We assume that the patience times of new and
reentrant customers may have different distributions. Under mild assumptions on
the general interarrival, service, delay and patience delay times, we investigate the
impact of the impatience differentiation upon the service performance in such
systems.
2 - Staffing and Control for Call Center Outsourcing with Rework
Jiheng Zhang, Hong Kong University of Science and Technology,
Clear Water Bay, Hong Kong, Hong Kong-PRC, j.zhang@ust.hk, Jin
Fang, Eser Kirkizlar
We study a system with both in-house and outsourcer call centers. With certain
probability, customers need to be rerouted to the in-house call center for further
help after receiving service at the outsourcer. The pooling of the two call centers is
allowed. Using a fluid approximation in a heavy traffic regime, we jointly
determine the optimal control rule and the staffing policy that asymptotically
minimize the staffing cost and long run holding cost subject to a service level
constraint.
3 - Non-FCFS Scheduling in Fluid Many-server Queues
Petar Momcilovic, Associate Professor, University of Florida,
303 Weil Hall, P.O. Box 116595, Gainesville, FL, 32611,
United States of America, petar@ise.ufl.edu, Avishai Mandelbaum
We consider non-FCFS scheduling policies in many-server fluid queues. In
particular, we examine time-varying queues under the assumption that the
scheduler knows realizations of customer patience/service times. Implementing a
non-FCFS policy improves the overall system performance in terms of the number
of customers that abandon during overloaded periods.
4 - Scheduling Parallel Servers in the Non-degenerate Slowdown
Diffusion Regime: Asymptotic Optimality
Itai Gurvich, Northwestern University-Kellogg School of
Management, Evanston, IL, United States of America,
i-gurvich@kellogg.northwestern.edu, Rami Atar
We consider the problem of minimizing holding costs in a parallel-server system
operating in a many-server heavy-traffic regime with non-degenerate slowdown
(NDS). The NDS many-server regime is distinct from existing heavy-traffic
regimes. As in the conventional heavy-traffic regime, the asymptotics are captured
by a Brownian control problem, the solution of which exhibits state-space
collapse. We prove an asymptotic lower bound and construct a sequence of
asymptotically optimal policies.
■ SA60
60- Remington- Hyatt
Joint Session RM/Aviation: Robust Airline
Optimization, Alliances and Revenue Sharing
Sponsor: Revenue Management & Pricing & Aviation Applications
Sponsored Session
Chair: Milind Sohoni, Indian School of Business, Gachibowli,
Hyderabad, 500032, India, milind_sohoni@isb.edu
1 - Reducing Flight Delays by Optimizing Block-time Allocation
Mazhar Arikan, University of Kansas, School of Business,
Lawrence, KS, United States of America, mazhar@ku.edu,
Vinayak Deshpande, Milind Sohoni
In this paper, we develop an approach to reallocate block-times across the
network of an airline and analyze the trade-off between total network arrival
delay minutes and network-wide block-time budget based on a stochastic traveltime
model. Using data acquired from a major U.S. airline, we construct an
efficient frontier by optimally allocating block-times while considering target ontime
arrival probability for each flight in the network.
INFORMS Phoenix – 2012
76
2 - Robust Gate Assignment to Reduce Tarmac Waiting Time
Amy Cohn, University of Michigan, Ann Arbor, MI,
United States of America, amycohn@umich.edu, Ryan Chen
We study the problem of assigning flights to gates at an airport, with the goal of
reducing delay associated with an inbound flight waiting on the tarmac because
its gate is still occupied by the preceding outbound flight. This can happen
because the outbound flight is late leaving, the inbound flight is early arriving, or
both. We develop MIP models to assign flights to gates so as to recognize the
inherent stochasticity of the system, and provide empirical analysis based on these
models.
3 - Revenue Sharing in Airline Alliances
Xing Hu, Assistant Professor, University of Oregon, 484 Lillis Hall,
1208 University of Oregon, Eugene, OR, 97401, United States of
America, xingh@uoregon.edu, Rene Caldentey, Gustavo Vulcano
We study codeshare, the practice of independent airlines collaboratively
marketing and operating fights. We propose a two-stage hierarchical approach to
study the revenue sharing rules and decentralized inventory controls from both
cooperative and non-cooperative game approach. Through both analytical and
numerical studies, we find that revenue sharing rule affects the system
significantly. We identify the existence and uniqueness of an admissible and
efficient revenue sharing.
■ SA61
61- Russell- Hyatt
Aviation Support Operations
Sponsor: Aviation Applications
Sponsored Session
Chair: Wenwei Cao, Georgia Institute of Technology, 765 Ferst Dr NW,
Atlanta, GA, United States of America, cww@gatech.edu
1 - Cost Allocation in Fractional Jet Ownership Programs
Wenwei Cao, Georgia Institute of Technology, 765 Ferst Dr NW,
Atlanta, GA, United States of America, cww@gatech.edu, Ozlem
Ergun, Lezhou Zhan, Ellis Johnson
Higher charter and reposition costs have plagued the profitability of the fractional
jet industry since its inception. Incentive programs and pricing adjustments are
introduced to offset these common costs incurred to service the customers. A
central problem in designing these programs is establishing a justifiable cost
allocation scheme. Furthermore, accurate estimates of cost-to-serve are valuable
information to other marketing and operational decisions. In this paper we
develop different mechanisms for the cost allocation problem. The
appropriateness and key trade-offs of the mechanisms are also discussed on the
basis of certain principles of equity and computational performance.
2 - An Integrated Optimal Decision Model for Ground Logistics and
Air Cargo Scheduling
Kwon Gi Mun, PhD Student, Rutgers Business School, #1009B, 1
Washington Park, Newark, NJ, 07102, United States of America,
kwongmun@eden.rutgers.edu
The mathematical model of two-tiered generalized scheduling problem has been
formulated. Thus the optimal assignment solution between airports and facilities
will be computed with the minimum transportation cost at the first stage. And
then the minimum total cost will be calculated with the optimal routing solution
of aircrafts. This research will use a mathematical model with practical constraints
and real data.
■ SA62
62- Borein A - Hyatt
Joint Session Auctions/MSOM: Competitive Sourcing
and Procurement
Cluster: Auctions & Manufacturing & Service Oper Mgmt
Invited Session
Chair: Cuihong Li, University of Connecticut, Storrs, CT, 06269,
United States of America, cli@business.uconn.edu
1 - Incentive Functions for Transportation Procurement Auctions
Diwakar Gupta, University of Minnesota, 111 Church Street S. E.,
Minneapolis, MN, 55455, United States of America,
guptad@me.umn.edu, Justin Azadivar, Yibin Chen
State Transportation Agencies (STAs) use variants of the first-price sealed-bid
auction mechanism to realize low cost, high quality, and fast completion of
highway and bridge construction projects. STAs pay incentives based on the
realized value of an attribute of the work, which may or may not be of value, but
bids do not explicitly include this attribute. We present models to identify costminimizing
incentive functions for agencies, net of any benefits that may accrue
from the attribute.