Formal DEVS modelling and simulation of a Flow-Shop relocation method without interrupting the production

International audienceThis paper presents an organisational method to keep the production going during the removal of a flow-shop. Assume a flow-shop system is to be moved on a new site and its production has to continue, our method can be applied to follow requests for the removal period. The method works as follows: we segment the removals in groups of machines and move them ones after the others. This method can be successfully executed provided that a prime condition is met: envisaging sufficient stocks’ plug between each group. The role of the latter stocks is to ensure operations’ production continuity between the old and the new site, when the non-operational group is being removed. Removal is then renewed until the whole line is moved and is operational on the new site. To validate this approach, we have used simulation and developed a model of the flow-shop according to coupled DEVS formalism. Our model enables to segment a production line. As a consequence, we can simulate the sequential displacement of machines’ groups towards the new site. Among the solutions suggested, those starting with the final group (finished products) and while finishing with the first group are much more effective. In this paper, we present and discuss some simulation results of an industrial case study. The results demonstrate the compared effectiveness of various strategies of removal, and make possible for the industrialist to envisage a good estimated project management

Environnement G-DEVS/HLA pour la simulation distribuée de systèmes de production multiprocessus

International audienceThis paper presents a simulation environment for manufacturing systems integrating control processes and operational processes. From the operational processes specification according to the JIS Z 8206 norm and from the control processes as Workflows standards, distributed G-DEVS models are generated. At first, the transformation of a process in G-DEVS models is described. Then, the implementation of a global simulation of the set of these models via an HLA architecture allowing interconnection and interoperability between the model components is presented. An illustration of the use of this environment is given in the microelectronic field. We conclude by the application of this approach to the study of the synchronizations between production lines and to the implementation of coupling between simulation and reality

Modeling and Simulation of Manufacturing Processes and Systems: Overview of Tools, Challenges, and Future Opportunities

Manufacturing is an important part of the modern economy. It is characterized by complexity in terms of systems, approaches, and interactions with intrinsic and extrinsic factors. Numerous efforts have been developed to use modeling and simulation tools to improve manufacturing efficiency and productivity and to achieve maximum quality, especially with the different mutations in the factories of today. This paper reviews the conventional and modern tools used in manufacturing system design and production improvement. Challenges that need to be addressed by the simulation community are discussed in depth. Finally, the evolution, advances, current practices, and future opportunities are discussed in the context of the contemporary manufacturing industry

Relocating subcontractor manufacturing and ensuring product quality

Diplomityössä tutkittiin elektroniikkavalmistuksen siirtoprojektin riskien tunnistamista ja hallintaa, sekä valmistuksen laadun varmistamista siirron yhteydessä. Työn tavoitteena oli luoda siirtokonsepti tulevia tuotannonsiirtoja varten ja varmistaa kyseessä olleen tuotannonsiirron onnistumisen ilman asiakasyrityksen tuotannon katkeamista. Tuotteiden laadun varmistamiseksi työssä kehitettiin validointi- ja verifiointisuunnitelma, jonka mukaan uuden tuotantolaitoksen tuotteiden laatu varmistettiin. Laadunvarmistuksen lisäksi siirtokonsepti kattaa myös muut siirtoprojektin vaiheet esivalmisteluista seurantavaiheeseen. Siirtokonsepti testattiin elektroniikkavalmistuksen siirron yhteydessä ja se todettiin toimivaksi ja hyödylliseksi. Konseptin avulla toteutettu tuotannonsiirto onnistui päätavoitteiden osalta hyvin ja kyseistä siirtokonseptia kannattaa diplomityön perusteella käyttää tulevissakin siirroissa.This master’s thesis studied the risk management and product quality ensurance in electronics manufacturing relocation project. The goal of this thesis was to create a project concept for future relocation projects and to ensure continuous operation of the customer’s manufacturing during the relocation project at hand. In order to ensure the product quality of the products from the new manufacturing location a validation and verification plan was created. On top of the quality ensurance the relocation concept covers all project phases from preparations to follow-up. The concept was found useful when it was tested with a relocation project of electronics manufacturing. The relocation project that was carried out using this concept met all the critical goals and based on the test the concept should be used in future relocation projects as well

How To Touch a Running System

The increasing importance of distributed and decentralized software architectures entails more and more attention for adaptive software. Obtaining adaptiveness, however, is a difficult task as the software design needs to foresee and cope with a variety of situations. Using reconfiguration of components facilitates this task, as the adaptivity is conducted on an architecture level instead of directly in the code. This results in a separation of concerns; the appropriate reconfiguration can be devised on a coarse level, while the implementation of the components can remain largely unaware of reconfiguration scenarios. We study reconfiguration in component frameworks based on formal theory. We first discuss programming with components, exemplified with the development of the cmc model checker. This highly efficient model checker is made of C++ components and serves as an example for component-based software development practice in general, and also provides insights into the principles of adaptivity. However, the component model focuses on high performance and is not geared towards using the structuring principle of components for controlled reconfiguration. We thus complement this highly optimized model by a message passing-based component model which takes reconfigurability to be its central principle. Supporting reconfiguration in a framework is about alleviating the programmer from caring about the peculiarities as much as possible. We utilize the formal description of the component model to provide an algorithm for reconfiguration that retains as much flexibility as possible, while avoiding most problems that arise due to concurrency. This algorithm is embedded in a general four-stage adaptivity model inspired by physical control loops. The reconfiguration is devised to work with stateful components, retaining their data and unprocessed messages. Reconfiguration plans, which are provided with a formal semantics, form the input of the reconfiguration algorithm. We show that the algorithm achieves perceived atomicity of the reconfiguration process for an important class of plans, i.e., the whole process of reconfiguration is perceived as one atomic step, while minimizing the use of blocking of components. We illustrate the applicability of our approach to reconfiguration by providing several examples like fault-tolerance and automated resource control