Frantisek Capkovic - Academia.edu (original) (raw)

Papers by Frantisek Capkovic

Computers in Industry, 1988

Abstract An application of a modification of Petri nets to mathematical modeling of discrete prod... more Abstract An application of a modification of Petri nets to mathematical modeling of discrete production processes utilized for a simulation of the flexible manufacturing systems is presented and an algorithm for the support of decision making in the control process of such systems based on the system model analysis is created. The algorithm makes the choice of a suitable control strategy possible in such a way that it automatically generates all potentially possible control strategies, automatically chooses the really possible ones and gives to an operator the chance to choose the most suitable realizable control strategy from the technological point of view.

Future Internet

Automated Manufacturing Systems (AMS) consisting of many cooperating devices incorporated into mu... more Automated Manufacturing Systems (AMS) consisting of many cooperating devices incorporated into multiple cooperating production lines, sharing common resources, represent industrial Multi-Agent Systems (MAS). Deadlocks may occur during operation of such MAS. It is necessary to deal with deadlocks (more precisely said, to prevent them) to ensure the correct behavior of AMS. For this purpose, among other methods, methods based on Petri nets (PN) are used too. Because AMS are very often described by PN models, two PN-based methods will be presented here, namely based on (i) PN place invariants (P-invariants); and (ii) PN siphons and traps. Intended final results of usage these methods is finding a supervisor allowing a deadlock-free activity of the global MAS. While the former method yields results in analytical terms, latter one need computation of siphons and traps.

Acta Polytechnica Hungarica, 2022

In Discrete-Event Systems (DES), deadlocks frequently occur. Flexible Manufacturing Systems (FMS)... more In Discrete-Event Systems (DES), deadlocks frequently occur. Flexible Manufacturing Systems (FMS) have the character of DES. Namely, FMS consist of many cooperating devices (like robots, machine tools, transport belts, etc.). Frequently, deadlocks occur because of insufficient resources. Petri Nets (PN) are often used to model FMS and to synthesize control for them. To deal with deadlocks, first of all, it is necessary to find and/or avoid them. There are several principal approaches for doing this-either by computing and analyzing the PN reachability tree (RT) or by finding PN model siphons. Then, in the former concept, the supervisor is synthesized by means of P-invariants of the PN model used, while in the latter concept the supervisor, based on siphons, is synthesized. In addition to these approaches, additional techniques can sometimes, be applied-e.g. a suitable utilization of added PN transitions.

Computing and Informatics, 2021

Solving the deadlocks avoidance problem in Resource Allocation Systems (RAS) in Discrete-Event Sy... more Solving the deadlocks avoidance problem in Resource Allocation Systems (RAS) in Discrete-Event Systems (DES) is a rife problem, especially in Flexible Manufacturing Systems (FMS), alias Automated Manufacturing Systems (AMS). Petri Nets (PN) are an effectual tool often used at this procedure. In principle, there are two basic approaches how to deal with deadlocks in RAS based on PN. They are listed and illustrated here. First of the approaches is realized by means of the supervisor based on P-invariants of PN, while the second one is realized by means of the supervisor based on PN siphons. While the first approach needs to know the reachability graph/tree (RG/RT) expressing the causality of the development of the PN model of RAS, in order to find (after its thorough analysis) the deadlocks, the second approach needs the thorough analysis of the PN model structure by means of finding siphons and traps. Next, both approaches will be applied on the same PN model of RAS and the effectiveness of the achievement of their results will be compared and evaluated. Several simple illustrative examples will be introduced. For the in-depth analysis of the problem of deadlock avoiding, next Part 2 of this paper is prepared, where the newest research will be introduced and illustrated on more complicated examples. If necessary (because of the limited length of particular papers), also the third part-Part 3, will be prepared.

Comput. Informatics, 2015

Timed Petri nets (TPN) and hybrid Petri nets (HPN), more precisely first-order HPN (FOHPN), are u... more Timed Petri nets (TPN) and hybrid Petri nets (HPN), more precisely first-order HPN (FOHPN), are used here in order to model, analyse and control discrete-event systems (DES) and hybrid systems (HS) of different kinds consisting of cooperating subsystems (modules, agents). Foremost, principles of the particular kinds of Petri nets (PN), including the primary place/transition PN (P/T PN), are explained. Then, two methods of the supervision are introduced. Finally, the corresponding kinds of PN are applied in four case studies in order to solve the problems of modelling, analysing and control. Namely, the throughput of transport systems (rail and road), flexible manufacturing systems (FMS) and the workflow (WF) of the evacuation process from an endangered area (EA) are handled.

Discrete event systems (DES) control based on interpreted Petri nets (IPN) is presented in this p... more Discrete event systems (DES) control based on interpreted Petri nets (IPN) is presented in this paper. While place/transition Petri nets (P/T PN) are usually used for modelling and control in case of controllable transitions and measurable places, the IPN-based models yield the possibility for the control synthesis also in case when P/T PN models contain some uncontrollable transitions and unmeasurable places. The creation of the IPN model from such a P/T PN model is introduced and the control synthesis is performed. The illustrative examples as well as the case study on a robotized assembly cell are introduced.

Vietnam Journal of Computer Science, 2018

An approach based on Petri nets pointing to the manner how to deal with failures in discrete-even... more An approach based on Petri nets pointing to the manner how to deal with failures in discrete-event systems is presented. It uses the reachability tree and/or reachability graph of the Petri net-based model of the real system as well as the synthesis of a supervisor to remove the possible deadlock(s). To illustrate the applicability of the approach to the detection and recovery of failures in DES modelled by Petri nets the case study on a railroad crossing is introduced.

Computing and Informatics, 2018

Discrete-Event Systems are discrete in nature, driven by discrete events. Petri Nets are one of t... more Discrete-Event Systems are discrete in nature, driven by discrete events. Petri Nets are one of the mostly used tools for their modelling and control synthesis. Place/Transitions Petri Nets, Timed Petri Nets, Controlled Petri Nets are suitable when a modelled object is deterministic. When the system model contains uncontrollable/unobservable transitions and unobservable/unmeasurable places or other failures, such kinds of Petri Nets are insufficient for the purpose. In such a case Labelled Petri Nets and/or Interpreted Petri Nets have to be used. Particularities and mutual differences of individual kinds of Petri Nets are pointed out and their applicability to modelling and control of Discrete-Event Systems are described and tested.

IFAC Proceedings Volumes, 1997

An alternative approach to modelling the discrete-event dynamic systems (DEDS) and to knowledge-b... more An alternative approach to modelling the discrete-event dynamic systems (DEDS) and to knowledge-based control of them is presented in this paper. Petri nets and oriented graphs are simultaneously used in order to express in analytical terms the new combined model of DEDS and to represent analytically knowledge about the control task specifications (like criteria, constraints, etc.) by means of such a new combine approach. Both the DEDS model and the knowledge base are simultaneously used in the procedure of the control system synthesIs.

Proceedings of the Fifth International Symposium on Business Modeling and Software Design, 2015

The present research aims to detect certain correlations between four economic indicators, agains... more The present research aims to detect certain correlations between four economic indicators, against which have been evaluated the economic entities of the European Union with 27 Member States, as split into four categories: micro, small, medium and large enterprises. The mathematical formalism employed for revealing these dependencies, particularly termed here 'positive' and 'negative consonances', is a novel decision support approach, called InterCriteria Analysis, which is based on the theoretical foundations of the intuitionistic fuzzy sets and the augmented matrix calculus of index matrices. The proposed approach can be useful in processes of decision making and policy making, and it can be seamlessly integrated and further extended to other related application areas and problems, where it is reasonable to seek correlations between a variety of economic and other indicators.

Singapore International Conference on Intelligent Control and Instrumentation [Proceedings 1992]

See back inner page for a list of recent BRICS Report Series publications. Copies may be obtained... more See back inner page for a list of recent BRICS Report Series publications. Copies may be obtained by contacting:

Proceedings of the 2000 IEEE International Symposium on Intelligent Control. Held jointly with the 8th IEEE Mediterranean Conference on Control and Automation (Cat. No.00CH37147), 2000

ABSTRACT A new view on discrete event dynamic systems (DEDS) modelling and control synthesis is p... more ABSTRACT A new view on discrete event dynamic systems (DEDS) modelling and control synthesis is presented. The adjacency matrix of an oriented graph is successfully utilized in the DEDS control synthesis procedure. The state reachability tree in both the straight-line system dynamics development and the backtracking one are generated. To solve the DEDS control synthesis problem a suitable combination of both these kinds of model dynamics development is utilized, namely, the intersection of both the state reachability trees yields all feasible trajectories of the system dynamics development, i.e., all realizable possibilities of how to reach the prescribed terminal state from the given initial one, are automatically found. To choose the most suitable solution of the control synthesis problem, rule-based knowledge about the control task specifications is utilized

Advances in Intelligent Systems and Computing, 2014

Timed Petri nets (TPN) and first order hybrid Petri nets (FOHPN) are tested here in order to mode... more Timed Petri nets (TPN) and first order hybrid Petri nets (FOHPN) are tested here in order to model transport systems and to find the suitable travel routes in different non-standard situations during the increased traffic density (i.e. at the bounded traffic or congestion). This work extends our previous work where the flexible routes in transport systems were found by means of the place/transition Petri nets (P/T PN). While at usage of the TPN only the time parameters are assigned to the P/T PN model transitions, the FOHPN model is different and it yields the continuous flows of vehicles.

Vietnam Journal of Computer Science, 2014

The evacuation process from endangered areas (EA) into safe spaces in crisis situations is modell... more The evacuation process from endangered areas (EA) into safe spaces in crisis situations is modelled by means of simple agents (gate-ways equipped by sensors). Petri nets (PN) are utilized here to model the EA structure as well as the agents and their cooperation. More precisely, timed PN (TPN) and first-order hybrid PN (FOHPN) are used to do this. Rooms, other spaces to be evacuated (corridors) and the safe spaces out of EA (where people are evacuated) are modelled by TPN places and FOHPN continuous places. Gateways are modelled by TPN subnets and by FOHPN continuous transitions. While the supervisor for the TPN gateways can be synthesized by means of place/transition PN (P/T PN), the blocks of FOHPN discrete places and transitions are used to affect the gateways. Depending on the immediate throughput of the gateways the escape time behaviour is found in the process of simulation. This paper is the extended version of the paper (Čapkovič Intelligent Information and Database Systems. LNAI. Springer, Cham Heidelberg 2014) presented in the ACIIDS 2014 conference.

Intelligent Systems Reference Library, 2015

Three kinds of Petri nets are utilized here in order to model and simulate segments of a transpor... more Three kinds of Petri nets are utilized here in order to model and simulate segments of a transport network . The segments are understood to be agents. A suitable cooperation of the agents makes it possible to model and simulate the vehicle flow propagation in the network. Place/transitions Petri nets (P/T PN) are utilized in order to find the safe and unambiguous structure of the controller for the traffic lights placed at the road intersections . After finding such a structure the time specifications are assigned to the P/T PN . Thus, timed Petri nets (TPN) arise from P/T PN . The TPN model yields the possibility to analyze the time relations among the traffic lights . Subsequently, hybrid Petri nets , more precisely first-order hybrid Petri nets , are used for finding the flows of vehicles moving on the roads within the bounds of possibility determined by the traffic lights . A generalization towards the more complicated segment is pointed out too. A possibility of the modular interconnection of the segments is mentioned in connection with the vehicle flow propagation in the transport network .

Lecture Notes in Computer Science, 2013

Place/transition Petri Nets (P/T PN) are utilized here to: (i) model modules of the endangered ar... more Place/transition Petri Nets (P/T PN) are utilized here to: (i) model modules of the endangered area (EA) having some attributes of simple agents; (ii) coerce the autonomous modules to a cooperation by means of supervision; (iii) model workflow of the evacuation process from EA. The approach is applied to analyzing the possibilities of evacuation EA being a part of a building and to finding the suitable free and safety escape routes. A supervisor is synthesized in order to force modules (agents) into a cooperation. The supervisor represents a desired goal of the cooperation and ensures its achievement. Thus, it makes the cooperation of modules possible. Its synthesis is based on the supervision methods known in DES (discrete-event systems) control theory. A simple case study of the building evacuation illustrates the proposed approach. The P/T PN based modelling the EA and the P/T PN-based evacuation workflow are proposed there. The differences between them as well as the possibilities of their mutual complementing are pointed out.

Lecture Notes in Computer Science, 2014

The evacuation process from endangered areas (EA) in cri- sis situations is modelled by means of ... more The evacuation process from endangered areas (EA) in cri- sis situations is modelled by means of simple agents (gate-ways equipped by sensors). Timed Petri nets (TPN) and first-order hybrid Petri nets (FOHPN) are utilized here to model the EA structure as well as the agents and their cooperation. Rooms, other spaces to be evacuated (cor- ridors) and safe spaces out of EA (where people are evacuated) are modelled by TPN places and FOHPN continuous places. Gate-ways are modelled by TPN subnets and by FOHPN continuous transitions. While the supervisor for the TPN gate-ways can be synthesized by means of place/transition Petri nets (P/T PN), the blocks of FOHPN discrete places and transitions are used to affect the gate-ways. Depending on the immediate throughput of the gate-ways the escape time behaviour is found in the process of simulation. This paper is a free continuation of (4) where the problem was solved solely by means of P/T PN.

Lecture Notes in Computer Science, 2011

The cooperation of autonomous agents is synthesized in order to satisfy demands imposed on a grou... more The cooperation of autonomous agents is synthesized in order to satisfy demands imposed on a group of agents or on MAS (multi agent systems). Petri nets (PNs), especially place/transition PNs (P/T PNs), are used for modelling the agents. The modular approach is utilized on that way. PN-based methods of discrete event systems (DES) control and supervising are utilized in order to synthesize the cooperation of the agents. The usefulness and applicability of the approach is demonstrated by examples and case studies.

Melecon 2010 - 2010 15th IEEE Mediterranean Electrotechnical Conference, 2010

ABSTRACT The alternative approach to the synthesis of agent cooperation in multi agent systems (M... more ABSTRACT The alternative approach to the synthesis of agent cooperation in multi agent systems (MAS) is proposed and presented. It is based on knowledge in both the area of DES control and the area of agent-based intelligent control. The agents are modelled by place/transition Petri nets (P/T PN). DES control knowledge is based on the P/T PN invariants and the Parikh's vector. The autonomous agents are forced to cooperate in order to achieve a goal prescribed for the whole group of agents. The theoretical introduction (mathematical description) of the approach is introduced and its applicability is illustrated on a case study and two simple examples. The approach seems to be suitable for material agents (inside of transport systems, manufacturing systems, etc.), social agents and so forth.

Proceedings of IEEE Symposium on Computer-Aided Control Systems Design (CACSD)

Thie paper presents a Petri nets-based approach to both modelling the discrete event dynamic syst... more Thie paper presents a Petri nets-based approach to both modelling the discrete event dynamic systems (DEDS) to be controlled and the representation of knowledge about details or specifications concerning the control task. In order to synthetise intelligent control systems for the DEDS a procedure utilizing the Petri nets-baaed model of both the DEDS and the knowledge representation (both of them expressed in analytical terms) is proposed here.