• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.202-214
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• 1994

A functional reduction method of Petri nets is proposed. The method is based on interpretation of relations and transitions with functions which map one series of a relation a another. In particular, we propose CF-join which combines two transitions to new one after reduction of the common places, CE-join which superpose two transitions to one after superposition of the common places, and EQ-join which reduces the common places, after the Petri nets were explained be a relational scheme. A reduced net can be obtained without changing the properties such as liveness and boundness.

• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.891-900
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• 2002

Timed Petri nets are one of the most important formalisms used to specify concurrent systems, However, timed Petri nets cannot represent the dynamics of systems within the formalism explicitly. Such incomplete formalisms make the modeling very difficult because modelers should know not only the formalism itself but also its problem-specific simulation algorithm. In this paper we present a formalism which can express the dynamics of systems and an simulator.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1994.10a
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• pp.653-657
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• 1994

A symbolic performance analysis approach for flexible for manufactring systems (FMS) can be formulated based on the integration of Petri Nets (PN) and moment generating function (MGF) concept. In this method, generalized stochastic Petri Nets are used to define performance models for FMS, then MGF nased approach for evaluating stochastic PN is used to derive performance parameters of PN, and finally system performance is calculated. A GSPN model of machine cell is shown to illustrate the proposed method for evaluating such performance indices as production rate, utilization, work-in-process and lead time. The major advantage of this method over existing performance evaluation of FMS is the ability to compute symbolic solutions for performance. Finally future research toward automating performance measure for GSPN models of FMS is discussed.

• Journal of Mechanical Science and Technology
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• v.19 no.5
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• pp.1123-1130
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• 2005

In view of the lack of efficient coordination of interdependent task in the collaborative design system, the mechanisms for temporal and resource coordination problems are established based on Petri Nets, respectively. Both of the mechanisms are encapsulated and implemented in the coordination component so as to increase the flexibility and acceptability of the system. We model the CSCW system based on Petri Nets for simulation, analysis and optimization. A case study on the overhead traveling crane is given to demonstrate and validate our theory.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.22 no.51
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• pp.231-240
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• 1999

A major concern in Concurrent Engineering is the control and management of workload in a period of process. As a general rule, leveling the peak of workload in certain period is difficult because concurrent processing is comprised of various processes, including overlapping, paralleling looping and so on. Therefore, the workload management with resource constraints is so beneficial that effective methods to analyze design process are momentous. This study presents the Timed Petri Nets approach of precedence logic networks, and provides an alternative for users to analyze constraint processes to resolve conflicts of resources. Another approach to Continuous Time Markov Chain using Stochastic Petri Nets is also proposed. These approaches are expected to facilitate resolving resource constrained scheduling problems more systematically in Concurrent Engineering environment.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.193-209
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• 1998

The objective of this paper is to present a methodology for design of the FMS by using a new modeling tool which is called SE&TPN(Safe Extended & Timed Petri Net). A FMS, which consists of various machine groups, may produce machine parts in different physical dimensions and lot size. The approach involves the SE&TPN modeling by Petri-nets. The proposed algorithm can handle determining of firing count vector by incidence matrix and adjustment of conflict using the marking of SE&TPN. The SE&TPN is defined as nets that can have at most one token in one place and can have elements such as permissive arcs and inhibitor arcs in addition to elements. The SE&TPN with permissive arcs and inhibitor arcs are intuitively direct approach to increase the modeling power of the SE&TPN. Finally, this paper is to develop a modulation to optimize the system problems of FMS using SE&TPN which describes exactly features of Petri Nets.

• The Transactions of the Korea Information Processing Society
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• v.2 no.3
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• pp.335-342
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• 1995

In this pater, we present a syntactic software complexity measure based on program control structure using Petri Nets. Since control structure in program may be segregated by three structures such as sequence, condition and iteration structures, we are proposed a structured complexity measure based on program control structure after represented by Petri Nets. Finally, we compare our result with other measures of program complexity.

• Journal of the Korea Society for Simulation
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• v.1 no.1
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• pp.37-47
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• 1992

This paper proposes an analysis method of petri nets(PNs) using the relational algebra(RA). More wpecifically, we represent PNs in relations of the relational model. Based on such representation, we first develop an algorithm for generating reachability trees of PNs. we then develop an algorithm for generating reachability trees of PNs. We then develop algorithms for analyzing properties of PNs, such as boundedness, conservation, coverability, reachability, and liveness. The advantage of this approach is as follows: First, the algorithms represented by RA can be easity converted to a query language such as SQL of the widely used, commerical relational database management systems(DBMSs). Second, we can alleviate the problem of state space explosion because relational DBMSs can handle large amounts of data efficiently. Finally, we can use the DBMS's query language to interpret the Petri nets and make simulation.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1289-1296
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• 2019

Non-functional requirements plays a critical role in designing variety of applications domain ranges from safety-critical systems to simple gaming applications. Performance is one of the crucial non-functional requirement, especially in control and safety systems, that validates the design. System risk can be quantified as a product of probability of system failure and severity of its impact. In this paper, we devise a technique to do the performance analysis of safety critical and control systems and to estimate performance based risk factor. The technique elaborates Petri nets to estimate performability to ensure system dependability requirements. We illustrate the technique on a case study of Nuclear Power Plant system. The technique has been validated on 17 safety critical and control systems of Nuclear Power Plant.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.433-437
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• 2005

The goal of our research is to develop a formal modeling methodology for supervisory and controlling systems that have artificially intelligent features. This approach is agent-based and central to the development of the model of mobility agent considering reactivity for real-time purpose and deliberation for optimal realization and safe-fail problems for critical systems like Intelligent Transportation Systems by high-level Petri net. By using nets within nets we investigate the concurrency of the system and the agent in one model without losing the needed abstraction, and synchronous channels are introduced to denote the coordination and communication. Finally an example is demonstrated.