DE / EN
Dr. Justus Arne Schwarz

Dr. Justus Arne Schwarz

Assistant Professor at the Chair of Production Management
University of Mannheim
Schloss Schneckenhof Ost, SO 229
68161 Mannheim
Phone:+49 621 181-1371
Fax: +49 621 181-1579
E-mail: schwarz(at)bwl.uni-mannheim.de

Research interests

Production systems, such as flow lines, operate in an uncertain environment. Therefore, robust planning approaches need to consider stochastic effects like random machine breakdowns, variable demand and supply. It is often assumed that production systems operate in steady-state. However, in many cases the production process is highly time-dependent, due to the influence of capacity ramp ups, seasonal demand patterns and deterioration. Hence, the analysis of time dependent system behavior is of special interest. In order to provide decision makers with adequate analysis tools and performance measures, innovative modeling approaches towards stochastic and dynamic systems are necessary. My research focuses on the development of time-dependent stochastic models for flow lines in continuous and discrete time domain, especially using fluid and diffusion approximations. The models aim to support decisions from the strategic down to the operational level. E.g. the decision about the number of parallel machines (design phase) or choosing the optimal number of Kanban cards (operational phase).

Refereed publications

Working Paper

Other publications

Presentations at conferences, workshops, and research seminars

  • Schwarz, J. A., G. P Kiesmüller, and R. Stolletz (2018): Optimal repair decisions in capacitated repair shops for flow lines, SMMSO 2019, Goslar, Germany, June 2019  
  • Schwarz, J. A. (2019): Optimizing Sales and Production Rollover Strategies Under Stochastic Demand and Random Yield. POMS 2019 28th Annual Conference, Washington D.C., USA, May 2019 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung)
  • Schwarz, J. A. and O. Karabag  (2019): Optimal rollover strategies under consideration of capacity constraints, Research seminar – TU Eindhoven, TU Eindhoven, Eindhoven, The Netherlands, April 2019.
  • Schwarz J. A. and R. Stolletz (2019): Impact of stochastic yield with learning on start of production.  11th Workshop for Supply Chain Management and Production, Obergurgl, Austria, March 2019.
  • Schnitzler, J. M., Schwarz, J. A., and R. Stolletz (2019): Impact of stochastic yield with learning on start of production. Productive4.0 Research Workshop, Istanbul, Turkey, January 2019.
  • Schwarz, J. A.  and R. Stolletz (2018):  Optimal repair decisions in capacitated repair shops for flow lines: First results. 7th Workshop on Queueing Theory, Obergurgl, Austria, December 2018.
  • Schwarz, J. A. and B. Tan (2018): Sales and Operations Planning for Product Rollovers under Limited Capacity, INFORMS Annual Meeting, Phoenix, USA, November 2018 (supported by DAAD)
  • Schwarz, J. A. (2018): Analyzing the impact of finite capacity on sales and operations planning for product rollovers. EURO 2018, Valencia, Spain, July 2018.
  • Schwarz, J. A. (2018): Sales and operations planning for product rollovers with finite production capacities. Manufacturing and Service Operations Management 2018 Conference, Dallas, USA, July 2018 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).
  • Schwarz, J. A. and R. Stolletz (2018): Structural properties of time-dependent flow production systems. StochMod18, Lancaster, UK, June 2018.
  • Schwarz, J. A. (2018): Sales and operations planning for product rollovers: Structural insights. 28. Workshop der Quantitativen Betriebswirtschaftslehre, Hoechst, Germany, March 2018.
  • Schwarz, J. A. (2018): Sales and operations planning for product rollovers, Research seminar - Mercator School of Management, University of Duisburg-Essen, Duisburg, Germany, January 2018.
  • Schwarz, J. A. and R. Stolletz (2017): Minimizing work-in-process inventory in time-dependent flow lines by proactive Kanban control, Automotive Workshop, Brunswick, September 2017.
  • Schwarz, J. A. and R. Stolletz (2017): Minimizing work-in-process inventory in dynamic Kanban systems. OR2017, Berlin, September 2017.
  • Schwarz, J. A. and R. Stolletz (2017): Structural properties of flow production with time-dependent processing rates. INFORMS Applied Probability Society Conference 2017, Evanston, Illinois, USA, July 2017.
  • Schwarz, J. A. and Stolletz, R. (2017): Numerical comparison of Kanban mechanisms for production systems with time-dependent processing times. SMMSO 2017, Acaya (Lecce), Italy, June 2017 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).
  • Schwarz, J. A. (2017): Product rollovers with finite production capacities: first results. 9. Workshop für Supply Chain Management und Produktion, Obergurgl, Austria, March 2017.
  • Schwarz, J. A. and R. Stolletz (2016): Structural properties of flow production lines for stationary, transient and time-dependent settings. 5th Workshop on Queueing Theory, Obergurgl, Austria, December 2016.
  • Schwarz, J. A. and R. Stolletz (2016): Minimizing work-in-process inventory in stochastic and time-dependent flow lines. OR 2016, Hamburg, Germany, September 2016.
  • Schwarz, J. A. and R. Stolletz (2016): A proactive approach to Kanban allocation in stochastic and time-dependent flow lines. POMS 2016 27th Annual Conference, Orlando, USA, May 2016 (supported by DAAD).
  • Schwarz, J. A. and R. Stolletz (2016): BAPLib - A library and classification of Buffer Allocation Problem instances in serial flow lines. 8. Forschungsseminar für Supply Chain Management und Produktion, Obergurgl, Austria, March 2016.
  • J. A. Schwarz and R. Stolletz (2015): Structural properties in stochastic and time-dependent flow lines. 4th Workshop on Queueing Theory, Obergurgl, Austria, December 2015.
  • Schwarz, J. A. and R. Stolletz (2015): The allocation of Kanban cards in stochastic and time-dependent production systems. OR 2015, Vienna, Austria, September 2015 (supported by IPID4all funds of the DAAD).
  • Schwarz, J. A. and R. Stolletz (2015): Performance analysis of time-dependent queueing systems: Survey and classification. 18th INFORMS Applied Probability Society Conference, Istanbul, Turkey, July 2015 (supported by IPID4all funds of the DAAD).
  • Weiss, S., J. A. Schwarz, and R. Stolletz (2015): Buffer Allocation Problems for stochastic flow lines with unreliable machines. SMMSO 2015, Volos, Greece, June 2015 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).
  • Schwarz, J. A. and R. Stolletz (2014): Performance analysis of time-dependent queueing systems: A survey and classification. 3rd Workshop on Queueing Theory, Obergurgl, Austria, December 2014.
  • Schwarz, J. A. (2014): A classification of approaches to the performance evaluation of time-dependent queues. 8th Young European Queueing Theorists Workshop, Eindhoven, Netherlands, November 2014 (invited talk).
  • Schwarz, J. A. and R. Stolletz (2014): Setting Kanban cards for non-stationary and stochastic flow lines via sampling. OR 56 - 56th Conference of the UK Operational Research Society, London, UK, September 2014 (supported by Julius-Paul-Stiegler-Gedächtnis-Stiftung).
  • Schwarz, J. A. and R. Stolletz (2014): Setting Kanban cards for production systems under non-stationary and stochastic operating environments. OR 2014, Aachen, September 2014.
  • Schwarz, J. A., G. Selinka, and R. Stolletz (2014): Analytical performance evaluation of time-dependent queues: A classification.  StochMod14, Mannheim, July 2014.
  • Schwarz, J. A. and R. Stolletz (2013): Setting Kanban cards for production systems under non-stationary and stochastic operating environments. 2nd Workshop on Queueing Theory, Obergurgl, Austria, December 2013.
  • Schwarz, J. A. and R. Stolletz (2013): A sampling approach for the analysis of time-dependent stochastic flow lines. SMMSO 2013, Kloster Seeon, May 2013.
  • Schwarz, J. A. and R. Stolletz (2013): Evaluation and optimization of buffer allocations in time-dependent stochastic flow lines. 23. Workshop für Quantitative Betriebswirtschaftslehre, Altleiningen, February 2013.
  • Schwarz, J. A. and R. Stolletz (2012): Time-dependent stochastic flow lines. Workshop on Queueing Theory, Obergurgl, Austria, December 2012.
  • Schwarz, J. A., R. Stolletz, and S. Göttlich (2012): Time-dependent stochastic tandem queues. Brownbag Seminar Operations Management & Operations Research, Mannheim, November 2012.
  • Schwarz, J. A. (2012): A discrete time approach to analyze the behavior of Milkrun supplied inventories. OR 2012, Hanover, September 2012.

Education

03/2012-04/2016    
Doctoral Studies in Business Administration, Chair of Production Management (Prof. Stolletz), University of Mannheim

10/2006-12/2011 
Studies in Business Engineering (Diploma), Karlsruhe Institute of Technology (KIT)

09/2009-06/2010 
Studies in Engineering and Technology Management (M.S.), Portland State University

07/2006 
Abitur, Gymnasium Oberalster, Hamburg

Awards and grants

  • Südwestmetall Förderpreis 2016, awarded by the Baden-Wuerttemberg Employers’ Association of the Metal and Electrical Industry,  for the Ph.d. thesis “Analysis of buffer allocations in time-dependent and stochastic flow lines”
  • Dieter Arnold Preis 2012, awarded by the “Wissenschaftliche Studiengesellschaft für Fördertechnik Karlsruhe e.V.“,  for the diploma thesis “Modellierung einer Serienfertigung mit Kanban-Heijunka-Steuerung und Materialbereitstellung über Milkrun-Zyklen” (Modeling of a Heijunka leveled Kanban controlled production system, with auxiliary materials distributed by Milkrun cycles)
  • Camelot Innovative Value Chain Thesis Award for the diploma thesis “Modellierung einer Serienfertigung mit Kanban-Heijunka-Steuerung und Materialbereitstellung über Milkrun-Zyklen” (Modeling of a Heijunka leveled Kanban controlled production system, with auxiliary materials distributed by Milkrun cycles)
  • GfPM Thesis Award 2012 for the diploma thesis “Modellierung einer Serienfertigung mit Kanban-Heijunka-Steuerung und Materialbereitstellung über Milkrun-Zyklen” (Modeling of a Heijunka leveled Kanban controlled production system, with auxiliary materials distributed by Milkrun cycles)
  • BVL Thesis Award 2012 for the diploma thesis “Modellierung einer Serienfertigung mit Kanban-Heijunka-Steuerung und Materialbereitstellung über Milkrun-Zyklen” (Modeling of a Heijunka leveled Kanban controlled production system, with auxiliary materials distributed by Milkrun cycles)
  • Fulbright Scholarship, 2009-2010
  • Scholarship of the Konrad Adenauer Stiftung, 2006-2011

Professional experience

09/2016-present
Assistant Professor (Akademischer Rat auf Zeit), Chair of Production Management (Prof. Stolletz), University of Mannheim

06/2016–08/2016         
Visiting Scholar, Koc University, College of Administrative Sciences and Economics, Turkey

05/2016–06/2016        
Visiting Scholar, Massachusetts Institute of Technology, Laboratory for Manufacturing and Productivity, USA

03/2012-04/2016          
Research Assistant, Chair of Production Management (Prof. Stolletz), University of Mannheim

04/2011-06/2011
Internship, The Boston Consulting Group GmbH, Johannesburg South Africa

11/2010-02/2011 
Internship, Robert Bosch GmbH, Karlsruhe

09/2008-10/2008 
Internship, Preh GmbH, Bad Neustadt a. d. Saale