DE / EN
Johannes Diefenbach (né Schnitzler), M.Sc.

Johannes Diefenbach (né Schnitzler), M.Sc.

Research Assistant at the Chair of Production Management
University of Mannheim
Schloss Schneckenhof Ost SO 213
68161 Mannheim
Phone: +49 621 181-1482
Fax: +49 621 181-1579
E-mail: diefenbach(at)bwl.uni-mannheim.de

My research focuses on the design and control of stochastic manufacturing systems. Problems include the optimal design of an assembly line with generally distributed task times or the start of production decision in the ramp-up of semiconductor manufacturing. 

  • Research interests

    Our research focuses on the design and control of stochastic manufacturing systems. Flow lines are common in many industries producing in large quantities. We analyze the assembly line balancing problem with stochastic task times. We consider the optimization problem of minimizing the number of stations with a constraint on the probability of finishing a work piece within the given cycle time. Technical precedence relations have to be fulfilled and each task has to be assigned to exactly one station.

    In addition to this design problem, we analyze the optimal start of production in a ramp-up process which faces stochastic yield. Yield problems occur when some of the produced products do not meet the specifications and can therefore not be used to fulfill demand. The yield distribution of a production process could change over time, depending on the past production volume.

  • Working papers

    •  Diefenbach, J, Stolletz, R, Stochastic Assembly Line Balancing: General Bounds and Reliability-based Branch-and-Bound

     

  • Presentations at conferences, workshops, and research seminars

    Diefenbach, J. M., Schwarz, J. A., and R. Stolletz (2019): Second thoughts on not so random sampling. 8th Workshop on Queueing Theory, Obergurgl, Austria, December 2019.

    Diefenbach, J. M. and R. Stolletz (2019): Data-driven line balancing: bounds and optimization. Young European Queueing Theorists, Eindhoven, Netherlands, October 2019

    Schnitzler, J. M., Schwarz, J. A., and R. Stolletz (2019): Impact of stochastic yield with learning on start of production. SMMSO 2019, Goslar, Germany, June 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.

    Schnitzler, J. M., Schwarz, J. A., and R. Stolletz (2018): First “random thoughts” on not so random sampling. 7th Workshop on Queueing Theory, Obergurgl, Austria, December 2018.

    Schnitzler, J. M. and R. Stolletz (2018): A branch and bound procedure for the chance-constrained stochastic assembly line balancing problem. Automotive Workshop, Frankfurt (Oder), November 2018

    Schnitzler, J. M. and R. Stolletz (2018): A branch and bound procedure for the stochastic assembly line balancing problem. EURO 2018, Valencia, Spain, July 2018.

    Schnitzler, J. M. and R. Stolletz (2018): A branch and bound procedure for the stochastic assembly line balancing problem. 28. Workshop der Quantitativen Betriebswirtschaftslehre, Hoechst, Germany, March 2018.   

    Schnitzler, J. M. and R. Stolletz (2017): A branch and bound procedure for the stochastic assembly line balancing problem. 6th Workshop on Queueing Theory, Obergurgl, Austria, December 2017.

    Schnitzler, J. M. and R. Stolletz (2017): A sampling approach for line balancing with stochastic task completion times. 27. Workshop der Quantitativen Betriebswirtschaftslehre, Klappholttal (Sylt), March 2017.

    Schnitzler, J. M. and R. Stolletz (2016): A sampling approach for line balancing with stochastic task completion times. 5th Workshop on Queueing Theory, Obergurgl, Austria, December 2016.

    Schnitzler, J. M. and R. Stolletz (2016): Line balancing with stochastic task completion times - numerical investigation of a sampling approach. Automotive Workshop, Hagen, September 2016.

  • Education

    09/2016 - present
    Doctoral Studies in Business Administration, Chair of Production Management (Prof. Stolletz), University of Mannheim

    09/2016 - present
    Doctoral Studies in Operations (Ph.D. Program), Center for Doctoral Studies in Business (CDSB), University of Mannheim

    09/2014 – 08/2016
    Mannheim Master Management (M. Sc.), University of Mannheim

    09/2011 – 08/2014
    Studies in Business Administration (B. Sc.), University of Mannheim

    08/2013 – 12/2013
    Studies in Business Administration (semester abroad), Montana State Univeristy

    09/2001 – 06/2010
    Abitur, Carl-Benz Gymnasium, Ladenburg

  • Awards and grants

    Scholarship of the Graduate School of Economic & Social Sciences (GESS), University of Mannheim (funded by the German Research Foundation (DFG) as part of the 'Excellence Initiative'), September 2016 - October 2017.

  • Professional experience

    09/2016 - present
    Research Assistant, Chair of Production Management (Prof. Stolletz), University of Mannheim

    03/2015 – 07/2016
    Working Student, Daimler AG, Mannheim - Production Scheduling

    07/2014 – 12/2014
    Intern, Daimler AG, Mannheim - Production Scheduling

    01/2013 – 2/2013
    Intern, PERI GmbH, Weißenhorn – Corporate Development

    06/2012 – 05/2012
    President of the Chapter Mannheim of MTP e.V.