4 Presentations

• 
  10:30 AM - 10:52 AM

  Time-window Optimization of the Home Health Care Services Districting Problem

  • Emna Benzarti, presenter, École Centrale Paris
  • Evren Sahin, École Centrale Paris
  • Yves Dallery, École Centrale Paris

  Home Health Care (HHC) which represents an alternative to the traditional hospitalization aims at maintaining or improving the clinical, psychological and social welfare of patients while containing operations costs. In this work, we are interested in the districting problem within the context of HHC service providers. This problem consists in grouping basic units into larger clusters, i.e. “districts”, so that these districts are “good” according to relevant criteria. The aim of the model developed in the paper is to guarantee the compactness of the districts as well as the continuity of care while balancing at best the workload of the different districts through the districting horizon in order to reach the objectives of quality and costs.

• 
  10:52 AM - 11:14 AM

  A Time-perspective on the Scheduler’s Job

  • José Larco, presenter, School of Industrial Engineering, Eindhoven University of Technology
  • V. Wiers, Eindhoven University of Technology
  • Jan Fransoo, Eindhoven University of Technology

  Time is the most critical resource at the disposal of schedulers. Hence, an adequate management of time from the schedulers may impact positively on the scheduler’s productivity and responsiveness to uncertain scheduling environments. This paper presents a field study of how schedulers make use of their time and makes explicit what time-management decisions and behaviors are available to a scheduler. Based on observations of the field study, we propose a framework to classify and specify key characteristics of common tasks to the scheduling job in terms of their impact on the workflow and workload of a scheduler. We then discuss how such a framework may be used to assess alternative time-management decisions of a scheduler.

• 
  11:14 AM - 11:36 AM

  Finish what you Start: Determinants of Self-interruption

  • José Larco, presenter, School of Industrial Engineering, Eindhoven University of Technology
  • Jan Fransoo, Eindhoven University of Technology
  • V. Wiers, Eindhoven University of Technology

  In white collar work such as the work in planning and scheduling functions, the execution of tasks is fragmented, where tasks are often abandoned without completion to be resumed later. Often such resume is due to selfinterruption of tasks. Using a field study we find evidence that the probability of self-interruption is significantly related to the number of outstanding tasks that have been started but not completed. Implications of this empirical finding to the operations management field are discussed.

• 
  11:36 AM - 11:58 AM

  Modelling Human Impact on Performance

  • A.G. (Ton) de Kok, presenter, Eindhoven University of Technology

  In this paper we discuss an inventory control problem where manufacturing lead times can be shortened in case short-term stockouts are foreseen. This problem occurs in many practical situations where multiple items are produced in a production department using common capacity and customer lead time for the items is positive. In that case the common capacity provides the flexibility of scheduling in production orders of items for which a stockout occurs within the customer lead time, while scheduling out production orders for items that have sufficient stock available to satisfy short-term demand. The exact reschedule-in and -out mechanisms are based on mental models of human planners and modelled as a black box. Using this blackbox model, we derive expressions for the probability of a stockout and the fill rate in case such replanning is allowed. We validate the heuristic analysis of the model by comparing model results with results from a case study. We discuss the importance of measuring the frequency of replanning for the application of the model.