Joachim Käschel

Real-time dynamic shop floor scheduling using Evolutionary Algorithms

Abstract Evolutionary Algorithms (EA) possess significant potential for solving manufacturing control problems. Despite the fact that the value of EA has become increasingly apparent over the past years, there are only few real-world applications of these methods. Proponents of the EA approach argue that one reason for this is the potential of these algorithms to adapt to sudden changes like machine breakdowns immediately by defining improved schedules in a continuous process. The new schedules often differ significantly from the previous schedules used by the supervisor before the changes occurred. This contradicts with organizational demands for predictable schedules that fix the work order of a machine at the beginning of a planning period allowing only minor changes afterwards. This is primarily caused by the inability of todays organizational systems to distribute new schedules quickly without causing major disturbance in the manufacturing process. While plant data acquisition (PDA) has been automated for years, distribution of work order information is in most cases still done manually. The authors introduce an evolutionary search algorithm for shop floor scheduling and show how to integrate the scheduler with a bidirectional PDA-system used for data collection as well as distribution of sequencing information. In addition, quality improvements of evolutionary tools by separating the time-consuming scheduling procedure from the EA and distributing it throughout intelligent data terminals is discussed.

An approach for the quantitative consideration of soft-facts for planning and controlling networked production structures

This contribution introduces an approach which makes it possible to take into consideration soft-facts in a quantified form for the establishment and operation of production networks. This approach, called polyhedral analysis, with its two main parameters connectivity and eccentricity, delivers valuable information which makes it possible to generate the promise of successful network cooperation, from a social perspective, and thus to guarantee the long-term satisfaction of the customer. Because of these features, polyhedral analysis might be interpreted as a methodology for making decisions within the scope of the selection of partners in networked production structures. In this connection, the concept of the non-hierarchical regional production network is introduced as a special field for the application of polyhedral analysis and for the integration of soft-facts during the generation of a network. Concerning these marginal conditions, the introduced methodology has an important function for distributed operations and decision-making.

Software zur Verpackungslogistik

ZusammenfassungDer vorliegende Beitrag stellt die Ergebnisse eines Vergleichs von Software zur Verpackungslogistik vor. Es werden vier Programmpakete gegenübergestellt, die von deutschen bzw. englischen Firmen derzeit angeboten werden.SummaryThe experience of comparing software for packing logistics is provided in this paper. Four packages of German and British firms are reviewed.

DYNAMICAL SYNTHESIS AND RECONFIGURATION OF COMPETENCE-CELL-BASED PRODUCTION NETWORKS

Abstract This paper deals with the issues in the dynamical synthesis and reconfiguration of production networks (PN) emerging by customer-oriented, temporary networking of core competencies of small and medium enterprises. The PN require support of the management concepts with information technologies. The paper presents a general concept of production network management called Extended Value Chain Management (EVCM) and the formal statement of the dynamical synthesis and reconfiguration of the competence-cell-based PN. This facilitates comprehensive understanding of design and control of such PN. The research contributes to advancing the theoretical foundations and the developing simulation and interoperability tools for management in PN.

Non-Hierarchical Production Networks — Order Fulfillment and Costing

Non-hierarchical regional production networks represent the conceptual vision of a virtual enterprise which is being researched within the framework of a new collaborative research center established at the Technical University of Chemnitz in January 2000. 11 is intended to improve competitiveness of small- and mediumsized enterprises (SME) through cooperation. In the first part of this study the model of a non-hierarchical production network and its mode of operation are presented. With the demands made on the costing system to be implemented in mind, its applications by SMEs are discussed in the second part.

A conceptual model and an information tool for the establishment of production networks based on small and smallest enterprises

Especially small and medium-sized enterprises possess not sufficient know-how and resources for developing and producing complex products desired by the customer. Collaborations within production networks with equal righted partners offers the chance to solve this problem. To enable the participation within the network, the paper illustrates the evolution and extension of the management and operation concept Extended Value Chain Management (EVCM), by which the whole life-cycle of such production networks, starting from the generation and ending by the decomposition of this network, is covered. Further, an information tool to support the EVCM is presented.

Methodologies for Dividing Profit in Networked Production Structures

This conceptual paper focuses the problem of dividing the profit earned in a production network to the different network members. In this context different theoretical approaches for profit division are introduced and discussed. It is assumed that a high degree of automation is aimed at by using the modern information and communication technology (ICT) intensively. The task of profit division is integrated in a comprehensive approach considering incentive and sanction mechanisms for harmonising the interests of the network members as well. In that context the basic assumptions of the New Institutional Economics serve as a theoretic basis.

A note to the paper “An efficient algorithm for linear programming” of V Ch Venkaiah

In Venkaiah [1] an algorithm for solving linear optimization problems based on the idea of the projective algorithm of Karmarkar, is proposed. The essential simplification in the new algorithm is the use of a fixed projection operator. In this way the algorithm requires onlyO(n2) operations to obtain a sufficient exact solution. In this note it is shown that in some special cases the algorithm of Venkaiah yields a feasible solution that is far from the optimal one.

Adaptation-Based Supply Chain Resilience

In this paper, we develop an adaptation-based supply chain resilience framework based on the control theoretic perspective for supply chain planning domain regarding the agility and disruption-resistance to achieve maximal economic performance and stability in supply chains. We propose a detailed analysis of supply chain resilience based on a mutual classification of flexibility and reliability elements. Subsequently, an algorithm of decision-making on supply chain planning regarding ensuring both supply chain reliability and flexibility is presented. The quantitative approaches and formal tools are based on the modern control theory in combination with operations research techniques, global stability, controlled adaptation and the use of attainable sets.

DIMA — Entscheidungsunterstützung bei der Planung und Steuerung von Produktions- und Logistiknetzwerken auf einer interdisziplinären methodologischen Basis

Planung und Steuerung von Supply Chains, insbesondere innerhalb von temporaren, auftragsbezogenen Netzwerken, werden einerseits wegen ihrer hohen Komplexitat und andererseits wegen groser Unsicherheiten in allen Prozessen erschwert. Die Aktivitat der Netzwerkelemente, eine hohere Strukturdynamik, eine grose Menge an unkontrollierbaren Faktoren, die Wechselbeziehungen zwischen konzeptionellen Modellen, mathematischen Modellen und deren informationstechnischer Umsetzungen sowie die Wechselbeziehungen von Planungs-, Monitoring- und Rekonfigurierungsmodellen gehoren zu den wesentlichen Besonderheiten der Supply Chain Modellierung. Zur Modellierung solcher komplexer Systeme kann nicht auf eine einzelne in sich geschlossene Methode zuruckgegriffen werden. Deshalb wird die Erarbeitung einer einheitlichen methodologischen Basis zur integrierten Analyse und Modellierung komplexer Produktions- und Logistiknetzwerke1 aufgrund eines intelligenten Zusammenspiels verschiedener Modellierungsverfahren angestrebt. Neue Perspektiven eroffnet hierzu die DIMA-Methodologie. Diese stellt einen interdisziplinaren Ansatz zur Modellierung von Produktions- und Logistiknetzwerken dar, der sowohl fur das Generieren solcher Netzwerke als auch fur deren Betreiben geeignet ist.