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Dr. Gregor Selinka

Dr. Gregor Selinka

Dissertation Project

Three Essays on the Performance Evaluation of Queueing Systems with Time-Dependent Parameters

Date of Defense

25 October 2016

Xing profile

Research

Queueing systems are often analyzed under the assumption that the system parameters are static and the queue performance reaches a steady-state after certain time. However, in reality, most queueing systems are characterized by the occurrence of dynamic behavior. Thus the arrival process can be time-dependent, e.g., the arrivals of customers at an airport check-in counter depend on the time of a day. In addition, the processing rate as well as the processing capacity can vary over time, e.g., due to a varying availability of differently skilled staff members in a production system. Therefore, when considering production or service systems, it can be very important to analyze the time-dependent development of the performance measures to gain reliable information about the system's behavior.


My research deals with the analysis of such non-stationary queueing systems and the calculation of their time-dependent performance. To this purpose, different numerical approximations are performed to determine the behavior of several performance measures such as the utilization, the work in process or the cycle time, under non-stationary conditions. Apart from the analysis of simple single-stage queueing systems, more complex systems are analyzed. Thereby the impacts of heterogeneous job types, e.g. passengers of different travel classes at check-in counters, or heterogeneous server types, e.g. machines with different speeds of operation, are considered. Furthermore, larger systems such as networks or queueing systems including characteristics such as abandonments and retrials are considered.

Refereed publications

Schwarz, J. A., G. Selinka, and R. Stolletz (2016): Performance analysis of time-dependent queueing systems: survey and classification. Omega 63, 170-189.

Selinka, G., A. Franz, and R. Stolletz (2016): Time-dependent performance approximation of truck handling operations at an air cargo terminal. Computers & Operations Research 65, 164-173.

Presentations at conferences, workshops, and research seminars

Selinka, G. and R. Stolletz (2015): Performance approximation of time-dependent queueing systems with abandonments. EURO 2015, Glasgow, UK, July 2015 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).

Selinka, G. and R. Stolletz (2015): Performance approximation of time-dependent queueing systems with abandonments. 25. Workshop für Quantitative Betriebswirtschaftslehre, Schwerte, March 2015.

Selinka, G. (2014): Time-dependent performance analysis of heterogeneous queueing systems. European Conference on Queueing Theory (ECQT 2014), Ghent, Belgium, August 2014 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).

Selinka, G. and R. Stolletz (2014): Performance analysis of heterogeneous queueing systems under time-dependent conditions. StochMod14, Mannheim, July 2014.

Schwarz, J. A., G. Selinka, and R. Stolletz (2014): Analytical performance evaluation of time-dependent queues: A classification. StochMod14, Mannheim, July 2014.

Selinka, G. (2013): Performance analysis of heterogeneous queueing systems under time-dependent conditions. OR 2013, Rotterdam, Netherlands, September 2013 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).

Franz, A., G. Selinka, and R. Stolletz (2012): Time-dependent Performance Approximation of Truck Handling Operations at an Air Cargo Terminal. International Conference on Airport Operations Management, Munich, September 2012.

Franz, A., G. Selinka, and R. Stolletz (2012): Time-dependent Performance Approximation of Truck Handling Operations at an Air Cargo Terminal. Brownbag Seminar Operations Management & Operations Research, Mannheim, September 2012.

Selinka, G. and R. Stolletz (2011): Analyzing the dynamic behavior of queueing systems. OR 2011, Zurich, Switzerland, September 2011.

Lerch, C. and G. Selinka (2010): Strategic Planning of Business Models in the Capital Goods Industry - A System Dynamics Approach. OR 2010, Munich, September 2010.

Lerch, C. and G. Selinka (2010): Dynamics of Business Models - Long-ranging Impact Assessment of Business Models in the Capital Goods Industry (Poster presentation). 28th International Conference of the System Dynamics Society, Seoul, Korea, July 2010.

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Education

2011 - 2015

Doctoral studies at the Chair of Production Management, Business School, University of Mannheim

2004 - 2010
Studies in Industrial Engineering and Management (Diploma), Karlsruhe Institute of Technology (KIT)

2002 - 2004
Studies in Aerospace Engineering (Diploma), University of Stuttgart