Development of a Mathematical Model for the Calculation of the Tool Appropriation Delay depending on the Tool Inventory

Compliance with punctual delivery under the high pressure of costs can be implemented through the optimization of the in-house tool supply. Within the Transfer Project 13 of the Collaborative Research Centre 489 using the example of the forging industry, a mathematical model was developed which determines the minimum inventory of forging tools required for production, considering the tool appropriation delay.

Cloud-Architektur für Privacy-Management in kollaborativen Logistikprozessen

Durch den großen Erfolg des Cloud Computing und der hohen Geschwindigkeit, mit der Cloud-Innovationen seither Einzug in die Praxis finden, eröffnen sich für die Industrie neue Chancen im Wettbewerb. Von besonderer Bedeutung sind die Möglichkeiten, Cloud-gestützte Geschäftsprozesse dynamisch, als direkte Reaktion auf einen Kundenauftrag, anzupassen und auszuführen. Dies gilt insbesondere auch für kooperative und unternehmensübergreifende Anwendungen, welche aus mehreren IT-Diensten verschiedener Partner bestehen. Gegenstand dieses Artikels ist die Vorstellung eines Konzeptes und einer Architektur für eine zentrale Cloud-Plattform zur Konfiguration, Ausführung und Überwachung von kollaborativen Logistik-Prozessen. Auf dieser Plattform können Geschäftsprozesse modelliert und in ihren Privacy-Eigenschaften parametrisiert werden. Die einzelnen Prozesselemente werden dabei mit IT-Diensten verknüpft, die beispielsweise auf externen Cloud-Plattformen ausgeführt werden. Ein Schwerpunkt der Veröffentlichung liegt in der Betrachtung der Erstellung, Umsetzung und Überwachung von Privacy-Anforderungen.

Fuzzy Multi-Objective Linear Programming and Simulation Approach to the Development of Valid and Realistic Master Production Schedule

Master production schedule (MPS) plays an important role in an integrated production planning system. It converts the strategic planning defined in a production plan into the tactical operation execution. The MPS is also known as a tool for top management to control over manufacture resources and becomes input of the downstream planning levels such as material requirement planning (MRP) and capacity requirement planning (CRP). Hence, inappropriate decision on the MPS development may lead to infeasible execution, which ultimately causes poor delivery performance. One must ensure that the proposed MPS is valid and realistic for implementation before it is released to real manufacturing system. In practice, where production environment is stochastic in nature, the development of MPS is no longer simple task. The varying processing time, random event such as machine failure is just some of the underlying causes of uncertainty that may be hardly addressed at planning stage so that in the end the valid and realistic MPS is tough to be realized. The MPS creation problem becomes even more sophisticated as decision makers try to consider multi-objectives; minimizing inventory, maximizing customer satisfaction, and maximizing resource utilization. This study attempts to propose a methodology for MPS creation which is able to deal with those obstacles. This approach takes into account uncertainty and makes trade off among conflicting multi-objectives at the same time. It incorporates fuzzy multi-objective linear programming (FMOLP) and discrete event simulation (DES) for MPS development.

Integration of Truncated Distributions in Exponential Family with Simulation Models of Logistics and Supply Chain Management

Truncated distributions of the exponential family have great influence in the simulation models. This paper discusses the truncated Weibull distribution specifically. The truncation of the distribution is achieved by the Maximum Likelihood Estimation method or combined with the expectation and variance expressions. After the fitting of distribution, the goodness-of-fit tests (the Chi-Square test and the Kolmogorov-Smirnov test) are executed to rule out the rejected hypotheses. Finally the distributions are integrated in various simulation models, e. g. shipment consolidation model, to compare the influence of truncated and original versions of Weibull distribution on the model.