Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167701
A. Ghariani, A. Toguyéni, E. Craye
Alarm processing is one of the functions of the monitoring and the supervision of automated productions systems. However, these systems become more and more complex. Actually, this induces that standard alarm processors do not manage efficiently all the alarms that occur. This paper deals with intelligent alarm processing system (IAPS). The goal of this type of system is to reduce the number of alarms that are presented to the operators and to assist them to select corrective actions in case of fault occurrence. In this paper, we propose a prototype developed under PROLOG. Different concepts such as validation, causal inhibition or synthesis alarms characterize this prototype features. The filtering process is independent of the nature of the process (continuous or discrete) and of the way the raw alarms are produced.
{"title":"A functional graph approach for alarm filtering and fault recovery for automated production systems","authors":"A. Ghariani, A. Toguyéni, E. Craye","doi":"10.1109/WODES.2002.1167701","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167701","url":null,"abstract":"Alarm processing is one of the functions of the monitoring and the supervision of automated productions systems. However, these systems become more and more complex. Actually, this induces that standard alarm processors do not manage efficiently all the alarms that occur. This paper deals with intelligent alarm processing system (IAPS). The goal of this type of system is to reduce the number of alarms that are presented to the operators and to assist them to select corrective actions in case of fault occurrence. In this paper, we propose a prototype developed under PROLOG. Different concepts such as validation, causal inhibition or synthesis alarms characterize this prototype features. The filtering process is independent of the nature of the process (continuous or discrete) and of the way the raw alarms are produced.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126480885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167665
J. Komenda
Coalgebraic techniques are applied for the supervisory control of discrete-event systems (DES) with partial observations. The paper is based on the formalism developed for supervisory control of DES in the full observation case, i.e., the notion of bisimulation, its generalizations (partial bisimulation and control relation), and the finality of the automaton of partial languages. The introduced concept of nondeterministic weak transitions yields a new concept of deterministic weak transitions. These are shown to be useful in the study of partially observed DES. They give rise to the relational characterizations of normality and observability. These characterizations lead to new algorithms for supremal sublanguages that are compared to the known ones in the literature.
{"title":"Computation of supremal sublanguages of supervisory control using coalgebra","authors":"J. Komenda","doi":"10.1109/WODES.2002.1167665","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167665","url":null,"abstract":"Coalgebraic techniques are applied for the supervisory control of discrete-event systems (DES) with partial observations. The paper is based on the formalism developed for supervisory control of DES in the full observation case, i.e., the notion of bisimulation, its generalizations (partial bisimulation and control relation), and the finality of the automaton of partial languages. The introduced concept of nondeterministic weak transitions yields a new concept of deterministic weak transitions. These are shown to be useful in the study of partially observed DES. They give rise to the relational characterizations of normality and observability. These characterizations lead to new algorithms for supremal sublanguages that are compared to the known ones in the literature.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129716757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167711
J. Sadr, R. Malhamé
Given a transfer line with individual machines reliability data, and given fixed size buffer zones for work in process across the transfer line, the objective is to determine the transfer line maximal sustainable mean production rate. We present a recursive algorithm based on a recently developed transfer line decomposition technique to evaluate a maximal sustainable throughput. The algorithm derived provably converges. Numerical results are compared with those obtained based on other competing algorithms in the literature for similar transfer lines.
{"title":"Unreliable transfer lines throughput maximization","authors":"J. Sadr, R. Malhamé","doi":"10.1109/WODES.2002.1167711","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167711","url":null,"abstract":"Given a transfer line with individual machines reliability data, and given fixed size buffer zones for work in process across the transfer line, the objective is to determine the transfer line maximal sustainable mean production rate. We present a recursive algorithm based on a recently developed transfer line decomposition technique to evaluate a maximal sustainable throughput. The algorithm derived provably converges. Numerical results are compared with those obtained based on other competing algorithms in the literature for similar transfer lines.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"57 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134295789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167708
A. Bemporad, A. Giua, C. Seatzu
For continuous-time switched linear systems, this paper proposes an approach for solving infinite-horizon optimal control problems where the decision variables are the switching instants and the sequence of operating modes. The procedure iterates between a "master" procedure that finds an optimal switching sequence of modes, and a "slave" procedure that finds the optimal switching instants. The effectiveness of the approach is shown through simple simulation examples.
{"title":"An iterative algorithm for the optimal control of continuous-time switched linear systems","authors":"A. Bemporad, A. Giua, C. Seatzu","doi":"10.1109/WODES.2002.1167708","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167708","url":null,"abstract":"For continuous-time switched linear systems, this paper proposes an approach for solving infinite-horizon optimal control problems where the decision variables are the switching instants and the sequence of operating modes. The procedure iterates between a \"master\" procedure that finds an optimal switching sequence of modes, and a \"slave\" procedure that finds the optimal switching instants. The effectiveness of the approach is shown through simple simulation examples.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":" 16","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132011622","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167673
B. Trouillet, A. Benasser, J. Gentina
We show that Petri net is a pertinent model to compute analytically the cyclic scheduling of flexible manufacturing system (FMS) with shared non-preemptive resources and assembly or disassembly of multiple components. The proposed method is based on two techniques: 1) the linearization of Petri net conflicts on resources; and 2) the linearization of weighted T-system will give a deterministic marked graph if a specific condition of normalization of the transitions is satisfied. We show that it is possible to compute the best cyclic scheduling in p steps with respect to the cycle time by means of an optimal (min,+) set of linear equations. By using (max,+) algebra it is possible to discriminate among the candidate solutions, the solutions giving the minimum time cycle.
{"title":"Transformation of the cyclic scheduling problem of a large class of FMS into the search of an optimized initial marking of a linearizable weighted T-system","authors":"B. Trouillet, A. Benasser, J. Gentina","doi":"10.1109/WODES.2002.1167673","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167673","url":null,"abstract":"We show that Petri net is a pertinent model to compute analytically the cyclic scheduling of flexible manufacturing system (FMS) with shared non-preemptive resources and assembly or disassembly of multiple components. The proposed method is based on two techniques: 1) the linearization of Petri net conflicts on resources; and 2) the linearization of weighted T-system will give a deterministic marked graph if a specific condition of normalization of the transitions is satisfied. We show that it is possible to compute the best cyclic scheduling in p steps with respect to the cycle time by means of an optimal (min,+) set of linear equations. By using (max,+) algebra it is possible to discriminate among the candidate solutions, the solutions giving the minimum time cycle.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132110321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167690
G. Schullerus, V. Krebs
This contribution addresses the estimation problem of holding times in timed event graphs. Based on the known Petri net topology the holding times are determined such that an equation error is minimized. The paper investigates the important issue of convergence of the estimated parameters to the true parameter values and shows that this objective can be achieved by applying particularly chosen input signals. A new iterative estimation procedure is proposed using these suitably designed input signals.
{"title":"A method for estimating the holding times in timed event graphs","authors":"G. Schullerus, V. Krebs","doi":"10.1109/WODES.2002.1167690","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167690","url":null,"abstract":"This contribution addresses the estimation problem of holding times in timed event graphs. Based on the known Petri net topology the holding times are determined such that an equation error is minimized. The paper investigates the important issue of convergence of the estimated parameters to the true parameter values and shows that this objective can be achieved by applying particularly chosen input signals. A new iterative estimation procedure is proposed using these suitably designed input signals.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134114146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167705
T. Ushio, S. Takai
This paper deals with a state feedback control problem for hybrid systems described by hybrid automata with forcible events. First, we introduce two semantics of the controlled hybrid automata using labeled transition systems. Next, we show necessary and sufficient conditions for the existence of state feedback controllers. The conditions are based on the transition systems. It is also shown that the conditions are preserved under a bisimilarity relation so that synthesis methods of state feedback controllers in discrete event systems can be applied in the hybrid systems if the bisimilarity relation is finitary. Finally, we show that there always exists the supremal subpredicate for which state feedback controllers exist.
{"title":"State feedback control of hybrid automata with forcible events","authors":"T. Ushio, S. Takai","doi":"10.1109/WODES.2002.1167705","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167705","url":null,"abstract":"This paper deals with a state feedback control problem for hybrid systems described by hybrid automata with forcible events. First, we introduce two semantics of the controlled hybrid automata using labeled transition systems. Next, we show necessary and sufficient conditions for the existence of state feedback controllers. The conditions are based on the transition systems. It is also shown that the conditions are preserved under a bisimilarity relation so that synthesis methods of state feedback controllers in discrete event systems can be applied in the hybrid systems if the bisimilarity relation is finitary. Finally, we show that there always exists the supremal subpredicate for which state feedback controllers exist.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120960195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167677
A. Khatab, É. Niel
While being placed resolutely within the reactive systems framework, this article approaches two techniques of failure recovery making it possible to characterize the essential properties of a safe controller but also to be able to generate its expression formally. The system, modeled as a timed discrete event system (TDES), will be characterized by two operating modes: nominal and degraded. When a failure occurs, the system continues its service on the basis of controllers that provide switching from the nominal to the degraded operating mode. In this spirit, concepts of controllability and stability may arise and we propose to investigate them within TDES. On the basis of these concepts, an algorithm is proposed for the synthesis of controllers able to carry out the system from its state of breakdown towards one of these operating modes.
{"title":"State feedback stabilizing controller for the failure recovery of timed discrete event systems","authors":"A. Khatab, É. Niel","doi":"10.1109/WODES.2002.1167677","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167677","url":null,"abstract":"While being placed resolutely within the reactive systems framework, this article approaches two techniques of failure recovery making it possible to characterize the essential properties of a safe controller but also to be able to generate its expression formally. The system, modeled as a timed discrete event system (TDES), will be characterized by two operating modes: nominal and degraded. When a failure occurs, the system continues its service on the basis of controllers that provide switching from the nominal to the degraded operating mode. In this spirit, concepts of controllability and stability may arise and we propose to investigate them within TDES. On the basis of these concepts, an algorithm is proposed for the synthesis of controllers able to carry out the system from its state of breakdown towards one of these operating modes.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124566442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167672
A.E.C. da Cunha, J. Cury, B. Krogh
The construction of a consistent abstraction plays a central role in the hierarchical control of discrete event systems. When constructing a consistent abstraction of a composed system it is first necessary to build the entire system, whose state space grows exponentially with the number of system components. Therefore it is desirable to build this consistent abstraction directly from the composition of consistent abstractions of the subsystems. But the composition of consistent abstractions of the subsystems is not necessarily a consistent abstraction of the composed system. This paper presents a method based on an assume-guarantee reasoning to build a consistent abstraction of the composed system by the composition of modified consistent abstractions of the subsystems. The method is then applied for a case of an Cooperative Adaptive Cruise Controller (CACC) system for an automobile.
{"title":"An assume-guarantee reasoning for hierarchical coordination of discrete event systems","authors":"A.E.C. da Cunha, J. Cury, B. Krogh","doi":"10.1109/WODES.2002.1167672","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167672","url":null,"abstract":"The construction of a consistent abstraction plays a central role in the hierarchical control of discrete event systems. When constructing a consistent abstraction of a composed system it is first necessary to build the entire system, whose state space grows exponentially with the number of system components. Therefore it is desirable to build this consistent abstraction directly from the composition of consistent abstractions of the subsystems. But the composition of consistent abstractions of the subsystems is not necessarily a consistent abstraction of the composed system. This paper presents a method based on an assume-guarantee reasoning to build a consistent abstraction of the composed system by the composition of modified consistent abstractions of the subsystems. The method is then applied for a case of an Cooperative Adaptive Cruise Controller (CACC) system for an automobile.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131656210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-02DOI: 10.1109/WODES.2002.1167700
M. Jafari, H. Darabi, T. Boucher, A. Amini
We treat supply chain of business enterprises as a distributed system of collaborative processes, where the system dynamics is governed by the events that occur within each enterprise and/or across several enterprises. While each enterprise has its own middleware for handling business transactions, we argue that there is also need for a meta-middleware across the whole supply chain. We present a formalism to build the control structure, which must be embedded in such a meta-middleware. We provide an illustrative example.
{"title":"A distributed discrete event dynamic model for supply chain of business enterprises","authors":"M. Jafari, H. Darabi, T. Boucher, A. Amini","doi":"10.1109/WODES.2002.1167700","DOIUrl":"https://doi.org/10.1109/WODES.2002.1167700","url":null,"abstract":"We treat supply chain of business enterprises as a distributed system of collaborative processes, where the system dynamics is governed by the events that occur within each enterprise and/or across several enterprises. While each enterprise has its own middleware for handling business transactions, we argue that there is also need for a meta-middleware across the whole supply chain. We present a formalism to build the control structure, which must be embedded in such a meta-middleware. We provide an illustrative example.","PeriodicalId":435263,"journal":{"name":"Sixth International Workshop on Discrete Event Systems, 2002. Proceedings.","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121565381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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