Fakultät Informatik und Mathematik
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Demands of customers for products and of the production for parts are being forecasted quite often in companies. The results are used extensively within the operational production planning and control by IT Systems like the SAP system. Hereby preferably methods based on exponential smoothing are being applied. Especially, in industrial practice it is expected that the pattern of the data change over time in such a way, that the parameters of the exponential smoothing have to be changed. In some companies thousands of items require forecasting, which is very laborious. With an adaptive method the parameters are modified in a controlled manner, as changes in the pattern occur. Two adaptive methods used in industrial practice are explained. Simulation experiments over a huge number of periods show when they should be used.
This paper deals with the problem of varying capacity load factors in master production scheduling. A simulation system of a production planning and control system and of a production system is described and an approach to compute the capacity loads from the simulation results is developed. This approach is used to measure period-specific capacity load factors for master production scheduling. The measured capacity load factors vary over time and show that the common assumption of the load factors being period-independent is inappropriate. A stochastic programming model to cope with this variation is described. This model is compared to a common linear programming model for master production scheduling in a simulation experiment. The results show that the use of the measured capacity load factor scenarios improves the quality of the estimation of the capacity load factors significantly.
Überwachung und Verbesserung von Losgrößenmodifikatoren eines PPS-Systems im laufenden Betrieb
(2010)
Unterstützung einer selbststeuernden Planung durch eine geeignete Erweiterung des SAP Systems.
(2012)
Durch eine Zusammenfassung von Produktionsaufträgen zu Losen werden Rüstaufwände zu Lasten von Beständen reduziert. Für einen möglichst guten Ausgleich dieser Kosten existieren in kommerziell verfügbaren IT-Systemen für die operativen Produktionsplanung und -steuerung eine Vielzahl von Losgrößenverfahren. Der Beitrag erläutert diese kurz und nennt Einstellhinweise unter industriellen Randbedingungen.