79 research outputs found
A bibliographic review of production line design and balancing under uncertainty
This bibliography reviews the solution methods developed for the design and balancing problems of production lines such as assembly and disassembly lines. The line design problem aims in determining the number of workstations along with the corresponding assignment of tasks to each workstation, while the line balancing problem seeks an assignment of tasks, to the existing workstations of the line, which ensures that the workloads are as equal as possible among the workstations. These two optimisation problems can be also integrated and treated as a multi-objective optimisation problem. This review considers both deterministic and stochastic formulations for disassembly lines and is limited to assembly line design and balancing under uncertainty. This bibliography covers more than 90 publications since 1976 for assembly and 1999 for disassembly
Équilibrage des lignes de désassemblage sous incertitude en présence de composants polluants
International audienceLe problème d'équilibrage d'une ligne de désassemblage consiste en l'affectation des tâches de désassemblage, I = { 1 , 2 ,..., N } , N ∈ N ∗ , à une séquence de postes de travail, J = { 1 , 2 ,..., M } , M ∈ N ∗ , sous les contraintes de précédence et du temps de cycle, C t . Cer- taines tâches impliquent le désassemblage des composants polluants. Les durées des tâches, ζ i , i ∈ I sont des variables aléatoires indépendantes normalement distribuées avec des paramètres connus i.e. ζ i ∼ N ( μ i ,σ i ) , t i > 0 , i ∈ I . Les contraintes de précédence sont modélisées par un graphe AND/OR, [1]. L'objectif est de minimiser le coût total de la ligne, en minimisant le nombre de postes de travail, ainsi que le nombre de postes sur lesquels le désassemblage des composants polluants est effectué. En même temps, il est nécessaire d'assurer que la probabilité d'arrêt de la ligne à cause d'un dépassement du temps de cycle sur un poste de travail soit inférieur à 1 − α , où α représente un seuil fixé par le décideur (de l'ordre de 5% )
Using argumentative agents to manage communities of Web services
This paper presents a framework for specifying Web services communities. A Web service is an accessible application that humans, software agents, and other applications in general can discover, compose, and invoke in order to satisfy users\u27 needs like hotel booking. Web services providing the same functionality are gathered into one community, independently of their origins. This framework shows how software agents that are able to argue, negotiate, and reason about Web services can be used to specify these Web services and to manage their respective communities. The use of what we call argumentative agents helps Web services in being better organized within communities and in achieving the goals for which they are conceived. The community is led by a master component, which among others attracts new Web services to the community, retains existing Web services in the community, and identifies the Web services in the community that will participate in composite Web services. All these operations are managed by interacting agents through flexible conversations made up by argumentation, persuasion, and negotiation phases called dialogue games. © 2007 IEEE
Conception combinatoire des lignes de désassemblage sous incertitudes
This thesis is dedicated to the problem of disassembly line design in uncertain context. A disassembly linecan be represented as a succession of workstations where tasks are performed sequentially at each workstation.The design of such a product recovery system can be reduced to a combinatorial optimization problem which seeksa line configuration that optimizes certain objectives under technical, economical and environmental constraints.We begin by describing the principal product recovery activities especially disassembly. Then, after a literaturereview on the design of production lines under uncertainty of task processing times, we focus our study on the consideration of the disassembly task time uncertainties. Hence, we present three main models as well as the associatedsolution approaches. The first one is interested in minimizing the line stoppages caused by the task processing timeuncertainties. The second one seeks to guarantee an operational level closely related with the line speed. The goal of thethird model is to integrate the line design and sequencing problems. At last, the performances of the proposed solutionapproaches are presented by analyzing the optimization results on a set of instances of industrial size.Les travaux présentés dans ce manuscrit portent sur la conception des lignes de désassemblageen contexte incertain. Une ligne de désassemblage consiste en unesuccession de postes de travail où les tâches sont exécutées séquentiellement au niveau de chaque poste. La conception d'un tel système, de revalorisationdes produits en fin de vie, peut être ramenée à un problème d'optimisation combinatoire.Ce dernier cherche à obtenir une configuration permettant d'optimiser certains objectifs enrespectant des contraintes techniques, économiques et écologiques.Dans un premier temps, nous décrivons les activités principales de la revalorisation des produitsen fin de vie, en particulier le désassemblage. Puis, après présentation des travaux de la littératureportant sur la prise en compte des incertitudes des durées opératoires lors de la conception des lignesde production, nous nous focalisons sur l'étude des incertitudes des durées opératoires des tâches de désassemblage.Ainsi, nous présentons trois modélisations principales avec leurs approches de résolution.La première s'intéresse à la minimisation des arrêts de la ligne causés par les incertitudes des durées des opérationsde désassemblage. La deuxième cherche à garantir un niveau opérationnel de la ligne lié à sa cadence de fonctionnement.Le but de la troisième modélisation est l'intégration des problématiques de conception des ligneset de séquencement des tâches de désassemblage. Enfin, les performances des méthodes de résolutionproposées sont présentées en analysant les résultats d'optimisation sur un ensemble d'instances de taille industrielle
Second order conic approximation for disassembly line design with joint probabilistic constraints
A problem of profit oriented disassembly line design and balancing with possible partial disassembly and presence of hazardous parts is studied. The objective is to design a production line providing a maximal revenue with balanced workload. Task times are assumed to be random variables with known normal probability distributions. The cycle time constraints are to be jointly satisfied with at least a predetermined probability level. An AND/OR graph is used to model the precedence relationships among tasks. Several lower and upper–bounding schemes are developed using second order cone programming and convex piecewise linear approximation. To show the relevance and applicability of the proposed approach, a set of instances from the literature are solved to optimality
Emergent technologies for inter-enterprises collaboration and business evaluation
International audienceConventional manufacturing systems are designed for intra-enterprise process management, and they hardly handle processes with tasks using extra-enterprise boundaries data. Besides, inter-enterprise collaboration and new IT enablers for industry 4.0 are becoming a highly topical issue to study, due to : (a) The emergence of new technologies mainly Internet of Things, big data processing and Cyber-Physical systems (b) The new customers' needs that face the SMEs. Many constraints and issues have to be taken into account before establishing Inter-enterprises collaboration, namely: The product information, the business processes and the heterogeneous data. Moreover, the exponential growth of data coming from all the enterprises causes several challenges regarding their exploitation. In this context, this study is interested in Big Data capabilities to help Small and Medium Enterprises to find out more lurking opportunities. We have focus on the combination between emergent IT technologies, mainly Big Data, and inter-interprises collaboration in order to provide an added value. The result of this study is a new approach, that could be adapted by SMEs, for new project evaluation within a network of enterprises
New Anonymity Notions for Identity-Based Encryption
The original publication is available at www.springerlink.comInternational audienceIdentity-based encryption is a very convenient tool to avoid key management. Recipient-privacy is also a major concern nowadays. To combine both, anonymous identity-based encryption has been proposed. This paper extends this notion to stronger adversaries (the authority itself). We discuss this new notion, together with a new kind of non-malleability with respect to the identity, for several existing schemes. Inter- estingly enough, such a new anonymity property has an independent application to password-authenticated key exchange. We thus come up with a new generic framework for password-authenticated key exchange, and a concrete construction based on pairings
A copula-based flexible-stochastic programming method for planning regional energy system under multiple uncertainties: A case study of the urban agglomeration of Beijing and Tianjin
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