Papers by Jacques Erschler
Special Session on Cooperative and Coordinated Decision in Distributed Enterprise
IFAC Proceedings Volumes, 2000
Abstract This session concern the Organization and the Management of Distributed manufacturing sy... more Abstract This session concern the Organization and the Management of Distributed manufacturing systems, as well in an intra-enterprise context as in an interenterprises context. In this distributed decision making and extended enterprise context, decision systems joining hierarchical structures and network structures are implemented. These new organizational fonns can not be considered on the unique point of view of local operational management. It is necessary to define and to implement new coordinating and cooperating mechanisms to ensure the flows synchronization and the decisions coherence in a reactive and proactive way.
Planning by Repairing and Cooperation in Multi-Project Management
IFAC Proceedings Volumes, 2000
Abstract Based on a real-world industrial case-study, the DIDOM project investigates new forms of... more Abstract Based on a real-world industrial case-study, the DIDOM project investigates new forms of industrial production strategies, having a dual trade-project structure, and involving distributed decisions, with a view to specify realistic decision-support tools adapted to such contexts. After introducing some features of multi-project management and our methodology, the paper presents the main results achieved in two main areas: on the one hand, the crucial role, in the decision process, of a workplan involving temporal landmarks, its construction and its repair, and, on the other hand, the cooperation procedures appearing in a distributed decision framework.
A Generic Design Framework for Decentralized Management: The DMU Model
IFAC Proceedings Volumes, 2000
Abstract A study of a state-of-the-art shows that most of proposed models and methods in the doma... more Abstract A study of a state-of-the-art shows that most of proposed models and methods in the domain of decentralized management are designed according to specific contexts although decentralization of decisions is very widespread at every level, inside or outside complex systems such as production systems or enterprises. As a consequence, the aim of this paper is to provide a generic framework for the design and the exploitation of decentralized management systems based on the model of DMU. The genericity of our model and associated design method support the diversity of contexts, decisions, management structures and constraints from the environment and the possible integration of existing tools and methods. An example in the domain of production is provided.
RAIRO - Operations Research, 1993
Revue française d'automatique, d'informatique et de recherche opérationnelle. Recherche opération... more Revue française d'automatique, d'informatique et de recherche opérationnelle. Recherche opérationnelle, tome 27, n o 1 (1993), p. 77-150. <http © AFCET, 1993, tous droits réservés. L'accès aux archives de la revue « Revue française d'automatique, d'informatique et de recherche opérationnelle. Recherche opérationnelle » implique l'accord avec les conditions générales d'utilisation (). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques
RAIRO - Operations Research, 1979
Potentiels sur un graphe non conjonctif et analyse d'un problème d'ordonnancement à moyens limite... more Potentiels sur un graphe non conjonctif et analyse d'un problème d'ordonnancement à moyens limites RAIRO. Recherche opérationnelle, tome 13, n o 4 (1979), p. 363-378 <http © AFCET, 1979, tous droits réservés. L'accès aux archives de la revue « RAIRO. Recherche opérationnelle » implique l'accord avec les conditions générales d'utilisation (). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques
RAIRO - Operations Research, 1985
L'accès aux archives de la revue « RAIRO. Recherche opérationnelle » implique l'accord avec les c... more L'accès aux archives de la revue « RAIRO. Recherche opérationnelle » implique l'accord avec les conditions générales d'utilisation (). Toute utilisation commerciale ou impression systématique est constitutive d'une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright. Article numérisé dans le cadre du programme Numérisation de documents anciens mathématiques
Interaction between constraints and decision making in scheduling problems
1981 20th IEEE Conference on Decision and Control including the Symposium on Adaptive Processes, 1981
ABSTRACT The main objectives of a scheduling problem result from a decision taken at an upper lev... more ABSTRACT The main objectives of a scheduling problem result from a decision taken at an upper level. In the presented approach, these objectives are taken into account through constraints in order to ensure a rigorous coordination between two successive decision levels. This paper looks at some questions which result from this problem definition : the characterization of feasible schedules, the comparison of schedules according to feasibility.
Advanced Information Technologies for Industrial Material Flow Systems, 1989
Real time production items to be performed have scheduling decision process is search for charact... more Real time production items to be performed have scheduling decision process is search for characteristics France scheduling problems are considered, when the release times and due dates. The real time based on an original approach, aiming at the of schedules compatible with the main manufacturing constraints to be satisfied (limit times, item routings, limited amount of available resources). At any time when a decisionhas to be made in real time, these characteristics allow to select actions which are coherent with the constraints. Two procedures to search for these characteristics and to use then for real time scheduling are described
Limited resource scheduling with execution time constraints
Task scheduling under constraints: An energy-based approach
Scheduling problems
RAIRO - Operations Research
Although recent methods used for designing production systems tend to reduce the size of some sch... more Although recent methods used for designing production systems tend to reduce the size of some scheduling problems by dividing production systems into elementary flexible cells, the diversity, the complexity and the existence in the industrial world of scheduling problems remain very important. The scientific literature is filled with papers on the subject with some very concentrated points upon particular problems or methods. This paper is a state of the art written by eleven French researchers. It tries to present the whole domain in a pedagogic form and to make the reader take advantage of the peculiar experience of each writer. This explains the development more important of some parts while other aspects are only recalled with references to complementary specific surveys or papers.
Decision-aid in job shop scheduling: A knowledge based approach
Proceedings. 1986 IEEE International Conference on Robotics and Automation
ABSTRACT This paper deals with operation scheduling on machines in a job shop. The jobs which con... more ABSTRACT This paper deals with operation scheduling on machines in a job shop. The jobs which consist of a set of related operations are supposed to be constrained by limit times (earliest starting times and due dates). The approach aims at generating restrictions on local scheduling decisions by only considering limit times and resource availability constraints (constraint based analysis). This is achieved through an inference process which is defined from generic knowledge arising in scheduling problems : limit times associated with each operation, logical sequencing conditions between operations, inference rules relating to limit times and sequencing conditions. A software implementation in PROLOG of a constraint-based analysis module is presented. Such a module may be used either in a static way in order to generate a plan over a certain horizon or in a dynamic way in order to help in making real time decisions. In this last case it can be held to act the part of a flexible planning function.
Production Planning & Control, 1994
This paper deals with decisions of workload temporal distribution in scheduling discrete and dive... more This paper deals with decisions of workload temporal distribution in scheduling discrete and diversified productions. A new way of formulating the scheduling problem is proposed, from which some concepts and tools are presented: The notion of Time Resource Interval objects, TRIs, allows the management of some technical (time and resource) aspects at the different levels of a hierarchical structuration of the set of decisions taken in the workshop, from "load distribution" ones, to "effective realization of the operations" others. Constraint-based reasoning handles different TRIs corresponding to a given kind of decisions. It helps to highlight the bounds or limits to be respected while deciding, to remain consistent according to an initial set of constraints, issued for example from an upper level of decisions. Decisions of load temporal distribution consist in readjustments of some time constraints on a set of planned operations, by taking into account the (or some more detailed) constraints on the resource(s) on which they have been planned, as finite capacity one, and/or minimal profitability. The analysis on temporal proximities of the planned operations, involves some particular structurations of the time axis into successive time intervals: those structurations are associated with sets of temporal bounds, and are called adjacent decompositions of time axis. Such a decomposition introduces some specific TRIs, associated with load constraints (coming from the planned operations), and resource constraints (coming from limited quantities of resource, or profitability concerns). By respecting the given time and resource constraints, they can "exchange" some quantities of load according to communicating vessels processes. Those phenomena have been modeled as bounded flows in a temporal network, and offer new flexible curves of load with finite capacities, to help the decision.
Consistency of the Disaggregation Process in Hierarchical Planning
Operations Research, 1986
This paper deals with the planning process of a manufacturing system in which the aggregation of ... more This paper deals with the planning process of a manufacturing system in which the aggregation of products sharing similar characteristics leads to a hierarchical structure. It gives special attention to the consistency of decisions in a two-level structure, and presents necessary and sufficient conditions for consistency of a disaggregation procedure. Using a subset of these conditions improves upon the disaggregation procedure proposed by Bitran and Hax (Bitran, G. R., A. C. Hax. 1981. Disaggregation and resource allocation using convex knapsack problems with bounded variables. Mgmt. Sci. 27 431–441.).
A New Dominance Concept in Scheduling n Jobs on a Single Machine with Ready Times and Due Dates
Operations Research, 1983
Scheduling a set of jobs on a single machine is studied where each job has a specified ready time... more Scheduling a set of jobs on a single machine is studied where each job has a specified ready time and due date (limit times). A dominance relationship is established within the set of possible sequences and results in an important restriction of the number of sequences to be considered in solving the feasibility problem. Establishing the dominance relationship leading to this restriction requires only the ordering of ready times and due dates and is thus independent of job processing times and of any change in limit times which does not affect the given order.
Journal of Scheduling, 2007
This paper describes a robust approach for the single machine scheduling problem 1|r i |L max . T... more This paper describes a robust approach for the single machine scheduling problem 1|r i |L max . The method is said robust since it characterizes a large set of optimal solutions allowing to switch from one solution to another, without any performance loss, in order to face the potential disruptions which occur during the schedule execution. It is based on a dominance theorem that characterizes a set of dominant sequences, using the interval structure defined by the relative order of the release and the due dates of the jobs. The performance of a set of dominant sequences can be determined in polynomial time by computing the most favorable and the most unfavorable sequences associated with each job, with regard to the lateness criterion. A branch and bound procedure is proposed which modifies the interval structure of the problem in order to tighten the dominant set of sequences so that only the optimal sequences are conserved.
A decision-making process for the real time control of a production unit†
International Journal of Production Research, 1976
ABSTRACT The scheduling of jobs on machines in a job-shop is considered using a multilevel decisi... more ABSTRACT The scheduling of jobs on machines in a job-shop is considered using a multilevel decision-making structure. The levels are coordinated by considering as constraints on one level the decision made on the preceding level. For job-shop scheduling a tool is proposed to enable one to find and to analyse the set of feasible schedules in the light of the decision taken on the previous level. The information obtained as to the earliest starting and latest finishing times for performing the operations, as well as the logical sequence constraints acts as decision aids for the scheduling of the operations. The decision is made by choosing, from amongst the actions which are possible in the light of the overall objective, an action which takes into account secondary elements and considerations particular to the job-shop.
Characterizing the set of feasible sequences for n jobs to be carried out on a single machine
European Journal of Operational Research, 1980
... The earliest and latest times of the operations then coin cide with the times of the jobs, in... more ... The earliest and latest times of the operations then coin cide with the times of the jobs, in the case of a first or a last operation, or with intermediate times which account for operations that come before and after in the technical order. ...
European Journal of Operational Research, 2006
This paper focuses on the characterization of a subset of optimal sequences for the famous two-ma... more This paper focuses on the characterization of a subset of optimal sequences for the famous two-machine flowshop problem. Based on the relative order of the job processing times, two particular interval structures are defined so that each job is associated with an interval. Then, using the Allen's algebra, the interval relationships are analysed and a sufficient optimality condition is established providing a characterisation of a large subset of optimal sequences. This set necessarily includes any Johnson's sequences together with numerous other optimal job sequences.
Applying new dominance concepts to job schedule optimization
European Journal of Operational Research, 1982
ABSTRACT This paper deals with scheduling of independent jobs constrained by earliest starting ti... more ABSTRACT This paper deals with scheduling of independent jobs constrained by earliest starting times and latest finishing times on a single machine. The purpose is to find a feasible schedule which minimizes the total elapsed time. Based on the limit times of the jobs, a new dominance concept is defined. Associated with a branch and bound procedure, it significantly reduces the number of solutions to consider for solving the defined optimization problem. The efficiency of the proposed concept has been tested by computational experiments.
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Papers by Jacques Erschler