-
Yan Chen entered the IEOR PhD program in 2017.
Here are our first four published papers:
-
Algorithms for the Upper Bound Mean Waiting Time in the GI/GI/1 Queue.
Queueing Systems, vol. 94, 2020, pp. 327-356.
[PDF].
-
Online supplement: ``Supplement to Algorithms for the Upper Bound Mean Waiting Time in the GI/GI/1 Queue''.
[PDF]
-
Extremal Models for the GI/GI/K Waiting-Time Tail-Probability Decay Rate.
Operations Research Letters, vol. 48, 2020, pp. 770-776.
[PDF].
-
Set-Valued Performance Approximations for the GI/GI/K Queue Given Partial Information.
Probability in the Engineering and Informational Sciences, published online September 25, 2020.
[PDF]
-
Appendix to Set-Valued Performance Approximations for the GI/GI/K Queue Given Partial Information.
[PDF]
-
Extremal GI/GI/1 Queues Given Two Moments:
Exploiting Tchebycheff Systems.
Queueing Systems, Queueing Systems, vol. 97, 2021, pp. 101-124, doi/10.1007/s11134-020-09675-7.
[PDF].
Here are our other completed papers:
-
Applying Optimization to Study Extremal GI/GI/1 Transient Mean Waiting Times. To appear in
Queueing Systems-->
[PDF].
-
Extremal GI/GI/1 Queues Given Two Moments: Three-Point and Two-Point Distributions.
[PDF].
-
Itai
received his PhD degree from Columbia University in May 2008 and joined the Kellogg School of Management at Northwestern University in the following summer.
He joined Cornell Tech in 2016 after spending eight years at Kellogg. Her returned to Kellogg in 2021.
Itai was in the doctoral program in the
Division of Decision, Risk and Operations
in the Graduate School of Business at Columbia University, starting in 2004.
While I served as Itay's principal dissertation advisor, Itay was also co-advised, and wrote papers with,
Mor Armony
from NYU and
Costis Maglaras
and Assaf Zeevi in the Division of Decision, Risk and Operations
in the Graduate School of Business at Columbia University.
Before coming to Columbia, Itai completed a masters degree at the Technion in Haifa, Israel,
writing a thesis with
Avishai Mandelbaum.
In November 2006 Itay won the Manufacturing and Services Operations Management (MSOM) student paper competition for his work with Mor Armony on cross selling and its effect on call center performance.
Here are our completed papers:
-
Queue-and-Idleness-Ratio Controls in Many-Server Service Systems.
Mathematics of Operations Research, vol. 34, No. 2, May 2009, pp. 363-396.
[PDF]
-
Service-Level Differentiation in Many-Server Service Systems
Via Queue-Ratio Routing.
Operations Research, vol. 58, No. 2, March-April 2010, 316-328.
(with Itay Gurvich)
[PDF].
-
Scheduling Flexible Servers with Convex Delay Costs in Many-Server
Service Systems.
Manufacturing and Service Operations Management), vol. 11, No. 2, Spring 2009, pp. 237-253.
published PDF.
-
Rouba received her Ph.D. from the IEOR Department
at Columbia in 2010. She completed postdoctoral fellowships with Pierre L'Ecuyer at the University of Montreal in 2010-20111
and in the CREATE program at McGill University with Vedat Verter in 2011-2012. She is on the faculty of University College London (UCL) School of Management
Here are our completed papers (and supplements):
-
Real-Time Delay Estimation Based on Delay History.
Manufacturing and Service Operations Management, vol. 11, No. 3, Summer 2009, pp. 397-415.
[PDF].
Articles in Advance from MSOM
-
Journal Online Appendix to "Real-Time Delay Estimation Based on Delay History."
Supporting material for paper above maintained on journal web page.
[PDF].
-
Supplement to "Real-Time Delay Estimation Based on Delay History."
Supporting material for paper above.
[PDF].
-
Real-Time Delay Estimation in Overloaded Multiserver Queues with Abandonment.
Management Science, vol. 55, No. 10, October 2009, pp. 1729-1742.
[PDF].
-
e-Companion to Real-Time Delay Estimation in Overloaded Multiserver Queues with Abandonment.
Management Science, 15 pages.
[PDF].
-
Supplement to "Real-Time Delay Estimation in Overloaded Multiserver Queues with Abandonment"
Supporting material for paper above.
[PDF].
-
Real-Time Delay Estimation in Call Centers.
Proceedings of the 2008 Winter Simulation Conference, Miami, Fl., December 7-10, 2008,
S. J. Mason, R. R. Hill, L. Moench, O. Rose (editors),
vol. I, 2009, pp. 2876-2883.
[PDF].
-
Real-Time Delay Estimation Based on Delay History in Many-Server Queues with Time-Varying Arrivals.
Production and Operations Management, vol. 20, No. 5, September-October 2011, pp. 654-667.
[PDF].
-
Delay Predictors for Customer Service Systems with Time-Varying Parameters.
Proceedings of 2010 Winter Simulation Conference}, December 2010 .
[PDF].
-
Wait-Time Predictors for Customer Service Systems with Time-Varying Demand and Capacity.
Operations Research, vol. 59, September-October 2011, pp. 1106-1118.
[PDF]
-
Song-Hee (also known as Hailey) completed her doctoral studies at Columbia in 2014.
After spending a year as a Postdoctoral Associate in Operations Management, at the Yale School of Managment, she joined Marshall School of Business at USC. Song-Hee joined SNU in 2021.
At Columbia Song-Hee focused on service systems with special attention to healthcare operations management. She was co-advised by Carri Chan and Marcelo Olivares from the Decision, Risk and Operations (DRO) Division of the Columbia Business School.
Here are our completed papers:
-
Statistical Analysis with Little's Law.
Operations Research, vol. 61, No. 4, July-August 2013, pp. 1030-1045.
[PDF].
-
Statistical Analysis with Little's Law, Supplementary Material: Technical Report.
[PDF].
-
Estimating Waiting Times with the Time-Varying Little's Law.
Probability in the Engineering and Informational Sciences, vol. 27, 2013, pp. 471-506.
[PDF].
-
Appendix to Estimating Waiting Times with the Time-Varying Little's Law.
[PDF].
-
Using Simulation to Study Statistical Tests for Arrival Processes
and Service Time Models for Service Systems.
Proceedings of the 2013 Winter Simulation Conference,
R. Pasupathy, S.-H. Kim, A. Tolk, R. Hill, and M. E. Kuhl, eds., Washington, D.C.
(with Song-Hee Kim)
[PDF].
-
Choosing Arrival Process Models for Service Systems:
Tests of a Nonhomogeneous Poisson Process.
Naval Research Logistics, vol. 61, No. 1, 2014, pp. 66-90.
[PDF].
-
Appendix to "Choosing Arrival Process Models for Service Systems:
Tests of a Nonhomogeneous Poisson Process".
[PDF].
-
Are Call Center and Hospital Arrivals Well Modeled by Nonhomogeneous Poisson Processes?
Manufacturing and Service Operations Management
[PDF].
-
Short online supplement to: "Are Call Center and Hospital Arrivals Well Modeled by Nonhomogeneous Poisson Processes?"
[PDF].
-
Appendix to: "Are Call Center and Hospital Arrivals Well Modeled by Nonhomogeneous Poisson Processes?"
[PDF].
-
The Power of Alternative Kolmogorov-Smirnov Tests Based on Transformations of the Data.
ACM Transactions on Modeling and Computer Simulation (TOMACS)
[PDF].
-
Appendix to The Power of Alternative Kolmogorov-Smirnov Tests Based on Transformations of the Data.
[PDF].
-
Poisson and Non-Poisson Properties in Appointment-Generated Arrival Processes: the Case of an Endocrinology Clinic.
Operations Research Letters, vol 43, 2015, pp. 247-253 (with Ponni Vel and Won Chul Cha).
[PDF].
-
A Data-Driven Model of an Appointment-Generated Arrival Processes at an Outpatient Clinic.
INFORMS Journal on Computing, vol. 30, No. 1, 2018, pp. 181-199.
(with Won Chul Cha).
[PDF].
-
Appendix to "A Data-Driven Model of an Appointment-Generated Arrival Processes at an Outpatient Clinic". (with Won Chul Cha).
[PDF].
-
Slides for talk at INFORMS 2015 in Philadelphia (with Song-Hee Kim and Won Chul Cha).
[PDF].
-
Yunan completed his thesis defense in July 2011
and joined the faculty of the Department of Industrial Engineering at the North Carolina State University in Raleigh
in August 2011, where has been ever since.
Here are our completed papers:
-
The G_t/GI/s_t+GI Many-Server Fluid Queue.
Queueing Systems, vol. 71, No. 4, 2012, pp. 405-444.
[PDF].
-
The G_t/GI/s_t+GI Many-Server Fluid Queue: Longer Online Version with Appendix.
[PDF].
-
Stabilizing Customer Abandonment in Many-Server Queues with Time-Varying Arrivals.
Operations Research, vol. 60, No. 6, November-December 2012, pp. 1551-1564, doi:10.1287/opre.1120.1104.
[PDF].
-
e-Companion.
[PDF].
-
Longer version with additional appendix.
[PDF].
-
A Network of Time-Varying Many-Server Fluid Queues with Customer Abandonment.
Operations Research, vol. 59, July-August 2011, pp. 835-846.
[PDF].
-
e-companion.
[PDF].
-
Longer version with additional appendix.
[PDF].
-
Large-Time Asymptotics for the G_t/M_t/s_t+GI_t Many-Server Fluid Queue with Abandonment.
Queueing Systems, vol. 67, 2011, pp. 145-182.
[PDF].
-
A Fluid Approximation for Large-Scale Service Systems: Extended Abstract.
Performance Evaluation Review, Special issue on 2010 MAMA conference.
[PDF].
-
Nearly Periodic Behavior in the The Overloaded G/D/S+GI Queue.
Stochastic Systems, vol. 1, No. 2, 2011, p. 340-410.
[PDF].
-
Many-Server Heavy-Traffic Limits for Queues with Time-Varying Parameters.
Annals of Applied Probability, vol. 24, No. 1, 2014, pp. 378-421.
[PDF].
-
A Many-Server Fluid Limit for the G_t/GI/s_t+GI Queueing Model Experiencing Periods of Overloading.
Operations Research Letters, vol. 40, 2012, pp. 307-312.
[PDF].
-
Algorithms for Time-Varying Networks of Many-Server Fluid Queues.
Informs Journal on Computing, vol. 26, No. 1, 2014, pp. 59-73.
[PDF].
- e-Companion
Algorithms for Time-Varying Networks of Many-Server Fluid Queues: e-Companion.
Informs Journal on Computing, vol. 26, No. 1, 2014.
[PDF].
-
Stabilizing Performance in Networks of Queues with Time-Varying Arrival Rates.
Probability in the Engineering and Informational Sciences, vol. 28, No. 4, 2014, pp. 419-449.
[PDF].
-
Approximations for Heavily-Loaded G/GI/n+GI Queues.
Naval Research Logistics, vol. 63, No. 3, April 2016, pp. 187-217, DOI: 10.1002/nav.21688
(with Yao Yu).
[PDF].
-
Appendix to "Approximations for Heavily-Loaded G/GI/n+GI Queues". (with Yao Yu)
[PDF].
-
Staffing a Service System with Non-Poisson Nonstationary Arrivals.
Probability in the Engineering and Informational Sciences,
vol. 30, June 2016, pp. 593-621.
(with Beixiang He).
[PDF].
-
Stabilizing Performance in a Service System with Time-Varying Arrivals and Customer Feedback.
European Journal of Operations Research, vol. 256, No. 2, 2017, pp. 473-486.
[PDF].
-
Appendix to: "Stabilizing Performance in Many-Server Queues with Time-Varying Arrivals and Customer Feedback".
[PDF].
-
Heavy-Traffic Limit for the Initial Content Process.
Stochastic Systems,
vol. 7, No. 1, 2017, pp. 95-142. (with A. Korhan Aras)
[PDF].
Here are slides from talks based on our work.
-
Multi-Server Queues with Time-Varying Arrival Rates,
Markov Lecture, INFORMS Applied Probability Society, presented at the INFORMS
national conference, Austin, TX, November 8, 2010.
(with Yunan Liu).
[PDF].
-
Queueing Models for Large-Scale Service Systems
Experiencing Periods of Overloading,
Seminar at MIT Operations Research Center, April 5, 2012
[PDF].
-
Ni Ma (2019) at Bloomberg AI
Ni Ma entered the IEOR PhD program in 2013 after receiving her MSFE degree from the Columbia masters program in financial engineering (MSFE).
She completed her dissertation defense and will be graduating in May 2019. She has joined Bloomberg AI.
Here are our completed papers:
-
Using Simulation to Study Service-Rate Controls to Stabilize Performance in
a Single-Server Queue with Time-Varying Arrival Rate
Proceedings of the 2015 Winter Simulation Conference, Huntington Beach, CA, December 6-9, 2015,
L. Yilmaz, W. K. V. Chan, I. Moon, T. M. K. Roeder, C. Macal, and M. D. Rossetti, eds. (with Ni Ma)
[PDF].
-
Slides for talk at WSC 2015 in Huntington Beach, CA (with Ni Ma).
[PDF].
-
Efficient Simulation of Non-Poisson Non-Stationary
Point Processes to Study Queueing Approximations,
Statistics and Probability Letters, vol. 102, 2016, pp. 202-207
(with Ni Ma)
[PDF].
-
A Rare-Event Simulation Algorithm for Periodic Single-Server Queues..
INFORMS Journal on Computing, vol. 30, No. 1, Winter 2018, pp. 71-89 (with Ni Ma).
[PDF].
-
Online Supplement to ``A Rare-Event Simulation Algorithm for Periodic Single-Server Queues''.
INFORMS Journal on Computing, vol. 30, No. 1, Winter 2018, pp. 71-89 (with Ni Ma).
[PDF].
-
Minimizing the Maximum Expected Waiting Time in a Periodic Single-Server Queue with a Service-Rate Control.
Stochastic Systems, under review(with Ni Ma).
[PDF].
-
Guodong received his Ph.D. form the IEOR Department at Columbia in 2010.
Guodong joined the faculty of the Department of industrial Engineering at the Pennsylvania State University in August 2010 and has been there ever since.
He is a tenured Associate Professor in the Harold and Inge Marcus Department of Industrial and Manufacturing Engineering at Penn State University. He is also an Associate Professor in Mathematics by courtesy.
Here are our completed papers:
-
Martingale Proofs of Many-Server Heavy-Traffic Limits for
Markovian Queues.
Probability Surveys, vol. 4, 2007, pp. 193-267. (with Rishi Talreja)
[PDF]. Alternative sources: DOI link.
arXiv link.
-
Service Interruptions in Large-Scale Service Systems.
Management Science, vol. 55, No. 9, September 2009, pp. 1499-1512.
[PDF].
-
Continuity of a Queueing Integral Representation in the M1 Topology.
Annals of Applied Probability, vol. 20, No. 1, January 2010, pp. 214-237.
[PDF].
-
Heavy-Traffic Limits for Many-Server Queues with Service Interruptions.
Queueing Systems, vol. 61, pp. 167-202.
[PDF].
-
Two-Parameter Heavy-Traffic Limits for Infinite-Server Queues.
Queueing Systems, vol. 65, 2010, pp. 325-364.
[PDF].
-
Two-Parameter Heavy-Traffic Limits for Infinite-Server Queues: Longer Version.
Supporting material for paper above.
[PDF].
-
Heavy-Traffic Extreme-Value Limits for Erlang Models.
Queueing Systems, vol. 63, 2009, pp. 13-32.
[PDF].
-
Two-Parameter Heavy-Traffic Limits for Infinite-Server Queues
with Dependent Service Times.
Queueing Systems, forthcoming.
[PDF].
- earlier version.
Heavy-Traffic Limits for Infinite-Server Queues in Series
with Time-Varying Arrival Rates and Splitting,
Allowing Dependent Service Times at Each Queue.
[PDF].
-
The Impact of Dependent Service Times on Large-Scale Service Systems.
Manufacturing and Service Operations Management, vol. 14, No. 2, Spring 2012, pp. 262-278.
[PDF].
-
Infinite-Server Queues with Batch Arrivals and Dependent Service Times.
Probability in the Engineering and Information Sciences, vol. 26, 2012, pp.197-220.
[PDF].
- Prepublished version with correct references to our previous papers;
reference [17] missing in published version.
-
Two-Parameter Heavy-Traffic Limits for Infinite-Server Queues
with Dependent Service Times.
Queueing Systems, vol. 73, No. 2, 2013, pp. 119-146.
[PDF].
Here is a previous paper by Guodong with Professor Martin Day from VPI:
-
Fluid Limits for Optimally Controlled Queueing Networks.
Journal of Applied Mathematics and Stochastic Analysis, vol. 2007, paper ID 68958, 19 pages,
doi:10.1155/2007/68958 (by Guodong Pang and Martin Day)
[PDF].
-
Kun Soo successfully defended his thesis in October, 2009, after which he received his Ph.D. from
the IEOR Department at Columbia. We conducted research on stochastic models in finance jointly with Professor Emanuel Derman.
Kun Soo also was co-advised and did research with Professor Tim Huh, now at the University of British Columbia. Kun Soo joined the faculty of the College of Business
in the the Korean Advanced Institute for Science and Technology (KAIST) in Seoul and then moved to the Department of Industrial Engineering at
Seoul National University in 2017.
Here are our three completed papers with appendices:
-
Markov Chain Models to Estimate the Premium for Extended Hedge Fund Lockups.
Wilmott Journal, vol. 1, No. 5-6, October-December 2009, pp. 263-293 (with Emanuel Derman).
[PDF].
-
A Stochastic-Difference-Equation Model for Hedge-Fund Relative Returns.
Quantitative Finance, vol. 10, 2010, pp. 701-733,
(with Emanuel Derman)
[PDF].
-
Continuous-Time Markov Chain Models to Estimate the Premium for Extended Hedge Fund Lockups.
Annals of Operations Research, vol. 211, No. 1, 2013, pp. 357-379.
[PDF].
-
Ohad received his Ph.D. from the IEOR Department in Columbia in 2010.
In 2010-2011 Ohad was a postdoctoral fellow with Bert Zwart at the C.W.I. in Amsterdam. In August 2011 Ohad joined the faculty of the Department of Industrial Engineering and Management Sciences at Northwestern University, where he has been ever since.
Here are our completed papers:
-
Responding to Unexpected Overloads in Large-Scale Service Systems.
Management Science, vol. 55, No. 8, August 2009, pp. 1353-1367.
[PDF].
-
A Fluid Approximation for Service Systems Responding to Unexpected Overloads.
Operations Research, vol. 59, September-October 2011, pp. 1159-1170.
Journal version: [PDF].
Longer version: [PDF].
-
An ODE for an Overloaded X Model Involving a Stochastic Averaging Principle.
Stochastic Systems, vol. 1, No. 1, 2011, pp. 59-108.
[PDF].
-
Longer version with additional appendix.
[PDF].
-
A Fluid Limit for an Overloaded X Model Via a Stochastic Averaging Principle.
Mathematics of Operations Research, vol. 38, No. 2, May 2013, pp. 294-349 (with Ohad Perry).
[PDF].
-
Diffusion Approximation for an Overloaded X Model Via a Stochastic Averaging Principle.
Queueing Systems, vol. 76, 2014, pp. 347-401.
[PDF].
-
Achieving Rapid Recovery in an Overload Control for a Large-Scale Service System.
INFORMS Journal on Computing, vol. 27, No. 3, Summer 2015, pp. 491-506,
published online, August 6, 2015. Permalink: http://dx.doi.org/10.1287/ijoc.2015.0642
[PDF].
-
Online Supplement to "Achieving Rapid Recovery in an Overload Control for a Large-Scale Service System". (with Ohad Perry)
[PDF].
-
Chattering and Congestion Collapse in an Overload Switching Control.
Stochastic Systems, vol. 6, No. 1, 2016.
[PDF].
-
Xu Sun entered the IEOR PhD program in 2014 after completing his MS in Applied Operations Research at the University of Waterloo in Canada. After completing his Ph.D. in 2019, Xu joined the faculty of the Department of Industrial and Systems Engineering, University of Florida, Gainesville.
Here are our completed papers:
-
Creating Work Breaks from Available Idleness.
Manufacturing and Service Operations Management, vol. 20, No. 4, 2018, pp. 721-736, DOI 10.1287/msom.2017.0682.
[PDF].
-
Appendix to: "Creating Work Breaks from Available Idleness" (with Xu Sun).
[PDF].
-
Delay-Based Service Differentiation with Many Servers and Time-Varying Arrival Rates.
Stochastic Systems, vol. 8, No. 3, 2018, pp. 230-263, doi/10.1287/stsy.2018.0015.
[PDF].
-
Online supplement to ``Delay-Based Service Differentiation with Many Servers and Time-Varying Arrival Rates''.
[PDF].
-
Optimal Battery Purchasing and Charging at Electric Vehicle Battery Swap Stations. .
European Journal of Operations Research, vol. 39, 2019, pp. 524-539; https://doi.org/10.1016/j.ejor.2019.06.019 (with Bo Sun and Danny H. K. Tsang).
[PDF].
Xu has also completed other research papers, both by himself alone and with others.
-
Asymmetric Kernel Density Estimation Based on Grouped Data with Applications to Loss Model.
Communications in Statistics-Simulation and Computation, vol. 43, 2014, pp. 657-672.
[PDF].
-
Heavy-Traffic Limits for Server Idle Times with Customary Server-Assignment Rules.
Operations Research Letters , vol. 46, No. 1, 2018, pp. 44-50,
[PDF].
-
A Dynamic Network Model of Interbank Lending - Systemic Risk and Liquidity Provisioning. Mathematics of Operations Research,
forthcoming. (with Agostino Capponi and David D. Yao).
[PDF].
-
Many-Server Service Systems with Autoregressive Inputs. submitted to Queueing Systems.
[PDF].
-
Rishi Talreja (2010) Two Sigma
Rishi successfully defended his thesis on September 11, 2009, after which he received his Ph.D.
for the IEOR Department at Columbia. Rishi is currently a Quantitative Researcher at Two Sigma
Here are our three completed papers and supplements to two:
-
Fluid Models for Overloaded Multi-Class Many-Server Queueing Systems
with FCFS Routing.
Management Science, vol. 54, No. 8, 2008, pp. 1513-1527.
[PDF].
-
Fluid Models for Overloaded Multi-Class Many-Server Queueing Systems
with FCFS Routing: Internet supplement.
Supporting material for paper with same title.
[PDF].
-
Martingale Proofs of Many-Server Heavy-Traffic Limits for
Markovian Queues.
Probability Surveys, vol. 4, 2007, pp. 193-267. (with Guodong Pang)
[PDF]. Alternative sources: DOI link.
arXiv link.
-
Heavy-Traffic Limits for Waiting Times in Many-Server Queues with Abandonments.
Annals of Applied Probability, vol. 19, No. 6, December 2009, pp. 2137-2175
[PDF].
Here is a paper by Rishi on distribution-valued heavy-traffic limits for the G/GI/infinity queue with Professor Josh Reed from NYU:
-
Distribution-valued heavy-traffic limits for the G/GI/infinity queue.
(by Josh Reed and Rishi Talreja). Annals of Applied Probability, vol. 25, No. 3, 2015, pp. 1420-1474.
[PDF].
Here is a paper by Rishi on order book dynamics with Professor Rama Cont from Columbia and Dr. Sasha Stoikov from Cornell:
-
A Stochastic Model for Order Book Dynamics.
(by Rama Cont, Sasha Stoikov and Rishi Talreja)
[SSRN link].
-
Wei You entered the IEOR PhD program in 2014.
Here are our completed papers:
-
Using Robust Queueing to Expose the Impact of Dependence in Single-Server Queues,
Operations Research, vol. 66, No. 1, 2018, pp. 184-199; doi:10.1287/opre.2017.1649.
[PDF].
-
E-companion to: "Using Robust Queueing to Expose the Impact of Dependence in Single-Server Queues"
[PDF].
-
Slides for talk at First Operations Day at NYU in 2018
[PDF].
-
Heavy-Traffic Limit of the GI/GI/1 Stationary Departure Process and its Variance Function
Stochastic Systems, vol. 8, No. 2, 2018, pp. 143-165.
[PDF].
-
Time-Varying Robust Queueing,
Operations Research, vol. 67, No. 6, November-December 2019, pp. 1766-1782; https://doi.org/10.1287/opre.2019.1846
[PDF].
-
The Advantage of Indices of Dispersion in Queueing Approximations.
Operations Research Letters, vol. 47, 2019, pp. 99-104; doi/10.1016/j.orl.2019.01.001.
[PDF].
-
Online supplement: ``Supplement On Robust Queueing Approximations for the GI/GI/1 Queue and Series of These Queues''.
[PDF]
-
Heavy Traffic Limits for Stationary Network Flows.
Queueing Systems, vol. 95, 2020, pp. 53-68; doi/10.1007/s11134-019-09645-8
[PDF].
-
Longer version.
(with Wei You)
[PDF].
-
-
A Robust Queueing Network Analyzer Based on Indices of Dispersion.
Naval Research Logistics, published online on July 4, 2021, https://doi.org/10.1002/nav.22010
[PDF].
-
Xiaopei Zhang entered the IEOR PhD program in 2015 after completing his MS in Statistics from Columbia.
He graduated in 2019 and then joined the New York office of DRW Holdings, Inc.
Here are our completed papers:
-
A Data-Driven Model of an Emergency Department.
Operations Research for Health Care vol. 12, No. 1, 2017, pp. 1-15.
[PDF].
-
A Data-Driven Model of an Emergency Department, Appendix: Additional Details.
[PDF].
-
Periodic Little's Law.
Operations Research, vol. 67, No. 1, January-February 2019, pp. 267-280; doi/10.1287/opre.2018.1766
[PDF].
-
A Central-Limit-Theorem Version of the Periodic Little's Law.
Queueing Systems, Queueing Systems, vol. 91, 2019, pp. 15-47; doi/10.1007/s11134-018-9588-8
[PDF].
-
Forecasting Arrivals and Occupancy Levels in an Emergency Department.
Operations Research for Health Care, vol. 21, 2019, pp. 1-18, https://doi.org/10.1016/j.orhc.2019.01.002
[PDF].
-
Jingtong Zhao entered the IEOR PhD program in 2016 after completing her BS in IEOR from Columbia with a concentration in
financial engineering (BSFE). We completed two papers before she entered our doctoral program.
She completed her Ph.D. advised by Professor Van-Anh Truong.
Here are our completed papers:
-
Staffing to Stabilize Blocking in Loss Models with Time-Varying Arrival Rates,
Probability in the Engineering and Informational Sciences, vol. 30, No. 2, April 2016, pp. 185-211, doi:10.1017/S0269964815000340 (with Andrew Li).
[PDF]
-
Many-Server Loss Models with Non-Poisson Time-Varying Arrivals.
Naval Research Logistics, vol. 64, No. 3, 2017, pp. 177-202.
[PDF]
-
Appendix to ``Many-Server Loss Models with Non-Poisson Time-Varying Arrivals''.
[PDF]