Informs 2015

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INFORMS Philadelphia – 2015
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3 - Estimation of Servers Utilization in an Unreliable Queueing
System with Stacked Servers
Maboubeh Madadi, University of Arkansas, Fayetteville, AR,
United States of America, , Richard Cassady,
Shengfan Zhang, Lisa Maillart
We consider a queueing system comprised of a set of identical servers that are
stored in a stack when not in use. In such cases, customers may find it more
convenient to select the server that is on top of the stack. We develop a
continuous-time Markov chain model to compute the cumulative, transient
utilization and age of each server based on the number of servers in the system,
the server’s initial position in the stack, the arrival rate and the service rate.
4 - Optimal Preventive Maintenance Planning in Anticipation of
Imperfect Implementation
Kai He, University of Pittsburgh, 1048 Benedum Hall 3700
O’Hara Street, Pittsburgh, PA, 15261, United States of America,
, Oleg Prokopyev, Lisa Maillart
Maintenance planners usually assume perfect implementation of their prescribed
preventive maintenance (PM) policies. However, the maintenance workers often
deviate from the intended PM policy resulting in imperfectly timed PM actions.
We formulate cost rate-minimizing models to investigate the impact of such
deviations, assuming that the actual PM time differs from the scheduled PM time
in a probabilistic manner. We establish results for age replacement with and
without minimal repair policies.
WD74
74-Room 204A, CC
Reliability III
Contributed Session
Chair: Faranak Fathi Aghdam, The University of Arizona, 3125 E.
Bellevue Street, Tucson, AZ, 85716, United States of America,
1 - A Reliability Model for Multi-State Systems with Multi-State
Components with Different Failures
Carlos Solorio, Assistant Professor, CETYS Universidad,
Calzada S/N, Mexicali, Mexico,
A general model that evaluates the reliability of complex engineering systems that
suffer soft failures due to common degradation of physical systems and
catastrophic failures due to sudden shocks that provoke powerful stresses is
presented. The general reliability model considers multi-state systems with multi-
state components, where system reliability is evaluated based on the states of the
components. Performance measures are presented that help us decide which
system is better.
2 - Optimal CBM Policies under the Gamma Degradation Process
David Han, University of Texas, One UTSA Circle, San Antonio,
TX, United States of America,
CBM is an effective method to reduce unexpected failures as well as the O&M
costs. This talk discusses the CBM policy with optimal inspection points under the
gamma degradation process. A random effect parameter is used to account for
population heterogeneities and its distribution is continuously updated at each
inspection epoch. The observed degradation level along with the system age is
utilized for making the optimal maintenance decision, and the structure of the
optimal policy is examined.
3 - An Opportunistic Condition-Based Maintenance Policy with Two
Degradation Thresholds
Joeri Poppe, KU Leuven, Naamsestraat 69, Leuven, 3000,
Belgium, , Robert Boute,
Marc Lambrecht
Condition-based maintenance (CBM) is a maintenance strategy that makes uses
of the actual condition of the component. We introduce CBM in combination
with preventive and corrective maintenance. We propose a CBM policy that relies
on two thresholds of the degradation level, which can initiate a maintenance
action on the monitored component. We find that major reductions in both
maintenance cost and system unavailability can be realised, compared to the
established maintenance policies.
4 - Reliability Study of High-k Bi-layer Dielectrics with Non-weibullian
Failure Time Distribution
Faranak Fathi Aghdam, The University of Arizona, 3125 E.
Bellevue Street, Tucson, AZ, 85716, United States of America,
Haitao Liao
As electronic devices get smaller, reliability issues pose new challenges due to
unknown underlying physics of failure. This necessitates new reliability analysis
approaches related to nano-scale devices. The time-dependent breakdown of
dielectric films is one of the most important reliability issues. In this research, we
study two new approaches for modeling the time to breakdown of high-k bi-layer
dielectrics.
WD76
76-Room 204C, CC
Simulation and Optimization
Contributed Session
Chair: Siyang Gao, Assistant Professor, City University of Hong Kong,
Tat Chee Avenue, P6605, AC1, Kowloon, Hong Kong - PRC,
1 - A Simulation Based Traffic Control Policy for Hazardous
Materials Transportation
Sara Masoud, The University of Arizona, A214, 1300 E. Fort
Lowell Rd,, Tucson, AZ, 85719, United States of America,
, Sojung Kim, Young-jun Son
A simulation-based traffic control policy for hazardous materials (hazmat)
vehicles is devised to enhance public safety without sacrificing traffic efficiency, by
considering two traffic control policies simultaneously: 1) Network Design which
restricts hazmat vehicles from freeways; and 2) Dual Toll Pricing which levies toll
on both hazmat vehicles and regular vehicles in tollways. The proposed approach
is demonstrated via AnyLogicÆ ABS software with a real traffic data of San
Antonio, Texas.
2 - General-Purpose Ranking and Selection
Soonhui Lee, UNIST, UNIST-gil 50, Ulsan, Korea, Republic of,
Barry Nelson
In this study we take a step toward general-purpose Ranking & Selection
procedures that work for many types of performance measures and output
distributions, including situations in which different simulated alternatives have
entirely different output distribution families. To obtain the required PCS we
exploit intense computation via bootstrapping, and establish the asymptotic PCS
of these procedures.
3 - Convex Risk Measures: Efficient Computations via Monte Carlo
Zhaolin Hu, Associate Professor, Tongji University,
School of Economics and Management, Shanghai, China,
In this paper, we study an important class of convex risk measures called utility-
based shortfall risk (SR). We develop efficient Monte Carlo methods for
estimation of SR, sensitivity analysis of SR, and optimization of SR. Numerical
experiments are studied extensively, which further demonstrate the effectiveness
of our methods.
4 - Territory Design under Uncertainty
Peter Verderame, Air Products and Chemicals, Inc., 7201
Hamilton Boulevard, Allentown, PA, United States of America,
, Subhajit Ghoshal, Erdem Arslan,
Pratik Misra
Territory design looks to maximize the efficiency of a company’s resources
through intelligent, objective placement and allocation of assets. Balancing
workload across territories is a critical factor for successful deployment; however,
projected workload is often uncertain which in turn greatly impacts design
robustness. We developed a sophisticated optimization-and-simulation-based
framework which explicitly considers the parametric or nonparametric
uncertainty surrounding workload forecasts.
5 - Efficient Feasibility Determination with Multiple Performance
Measure Constraints
Siyang Gao, Assistant Professor, City University of Hong Kong, T
at Chee Avenue, P6605, AC1, Kowloon, Hong Kong - PRC,
, Weiwei Chen
Feasibility determination has emerged as a widely applied problem in simulation
optimization. It seeks to provide all the feasible designs from a finite set of design
alternatives. In this paper, we consider the this problem in presence of multiple
performance measure constraints. The optimal solution to maximize the
probability of correct selection is derived under asymptotic approximation. The
numerical testing shows that our approach can enhance the simulation efficiency
significantly.
WD76