• The Journal of Korean Institute of Communications and Information Sciences
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• v.14 no.3
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• pp.197-206
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• 1989

In this paper, we represent an improved algorithm of performance evaluation for communication protocol. It is an algorithm that analyzes Extended Timed Perti Net models including time which have been successfully used to model and evaluate the performance of distributed system. While Timed Petri Nets generally limted to free-choice and safe nets, our algorithm permits the construnction of elegant models of restricted concurrent processing. Furthermore, to reduce the state space size of Timed Reachability Graph, we improve the algorithm by using Maximum Firing Rule and sets of simultaneously firing transitions. Procedures for constructing of Timed Reachability Graphs and analyzing are presented, and we demonstrate the usefulness of this algorithm by applying it to the analysis of the communication protocol.

• The KIPS Transactions:PartD
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• v.11D no.1
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• pp.115-122
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• 2004

Software system modeling has a goal for finding and solving system's problems by describing and analyzing system model in formal notations. Petri nets, as graphical formalism, have been used in describing and analyzing the software systems such as parallel systems, real-time system, and protocols. In the analysis of Petri nets, general system properties such as deadlock and liveness are analyzed by the reachability analysis. On the other side, specific properties such as functional requirements and constraints are checked by model-checking. However, since these analysis methods are based on enumeration of ail possible states, there nay be state explosion problem, which means that system states exponentially increase as the size of system is larger. In this paper, we propose a new method for mechanically checking system properties with avoiding state explosion problem. At first, system properties are described in property nets then the system model and the property net are composed and analyzed. In the compositional analysis, system parts irrelevant to the specific property are reduced to minimize the analysis domain of the system. And it is possible to mechanically check whether a specific property is satisfied or not.

• Journal of the Korea Society for Simulation
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• v.14 no.1
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• pp.19-32
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• 2005

In this study, a distributed simulation of Petri net models under HLA/RTI framework is considered. Throughout our modeling experiences, it is recognized that the proper use of interface specification and time management services are important in order to achieve successful implementation of RTI. The interfacing tokens between Petri net models are distinguished as information entity and physical entity. Both entities are modeled as InteractionClass in order to send and receive messages. For the synchronization of local simulation clocks, a conservative method with NERA service is considered. A cell manufacturing system is modeled and implemented with RTI to illustrate the distributed simulation of Petri net models.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.1727-1731
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• 2003

In this paper we proposed backward fuzzy Petri-net to diagnoses faults in power systems by using the time sequence information of protection system. As the complexity of power systems increases, especially in the case of multiple faults or incorrect operation of protective devices, fault diagnosis requires new and systematic methods to the reasoning process, which improves both its accuracy and its efficiency. The fuzzy Petri-net models of protection system are composed of the operating process of protective devices and the fault diagnosis process. Fault diagnosis model, which makes use of the nature of fuzzy Petri-net, is developed to overcome the drawbacks of methods that depend on operator knowledge. The proposed method can reduce processing time and increase accuracy when compared with the traditional methods. And also this method covers online processing of real-time data from SCADA (Supervisory Control and Data Acquisition)

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.5
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• pp.695-707
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• 1993

Marked Petri Net(MPN) is used to analyze communication complexity with respect to the maximum number of concurrently active rendezvous. But, because it cannot represent timed & probability characteristics explicitly, it is not used to analyze the new execution time of complexity with respect to the communication. Thus to effectively analyze that execution time complexity, we propose Ada Tasking Structure Nets (ATSN) introduced restrictive conditions : net reduction rules, execution time, and probability. Finally, we show the powers of analyze of communication complexity with ATSN.

• The Transactions of the Korea Information Processing Society
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• v.6 no.10
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• pp.2797-2808
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• 1999

Timing Constraint Petri Nets(TCPN) extend petri nets by adding timing constraints, it is provide a formal method for the modeling and analysis of real-time system. A real-time schedulability analysis decide that a set of concurrent processes will always meet its deadline. In this paper, we present TCPN model for real-time system include timing constraints and propose a schedulability analysis algorithm using them. Also, When the TCPN model is unscheduleable under the imposed timing constraints, we propose a recovery technique that will be scheduleable by the system specification modifying or timing constraints relaxing in the optimized time.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.5
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• pp.9-18
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• 1997

The petri net is a graphic model which is adaptable in modeling a complex concurrent parallel ssystem, and it is widely used in the fields of industrial enginering, computer science, electric engineeringand chemistry. Recently, the net is applied to the communication protocol, and extended to represent complex systems. There are several extended petri nets named as TPN (timed petri net), SPN (stochastic petri net), FPN(fuzzy petri net) and TFPN(timed fuzzy petri net). Accodingly, this SPN (stochastic petri net), FPN (fuzzy petri net) and TFPN(timed fuzzy petri net). Accodingly, this paper proposes an advanced communication protocol modeling method using the fuzzy value of the transition and firing delay time as the arguments of the function. The proposed method can produce clearer firing rules, and it is supposed to be used to design and analyse communication protocols in great effection.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.66-66
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• 2000

In this parer, we introduce an algorithm to control flows of the traffic in multi-intersections. It is pointed out that the main problem in traffic control is how to resolve the congested situations for the particular time-durations and directions. The heavy load to a certain direction usually leads the intersection to congested situations, and the adjacent intersections are affected. We control and analyze the traffic flow of multi-intersections consisting of five intersections, in which four intersections are linked to the four directions of the central one. The entrance of vehicles of each direction is described using the concept of probability. We compare the performance of the pretimed signal controls to the traffic adaptive signal controller using a Petri Net simulation tool, Exspect.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.6
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• pp.540-549
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• 2001

An implementation method for chip-mounter simulator is proposed to improve the productivity and utility of electronic assembly lines. The simulator emulates the assembly sequence graphically to verify the chip mounter program in offline. It also presents functions of time estimation and productivity analysis considering the error probability. To increase the flexibility of simulator, stochastic petri nets are applied to modeling of the assembly sequence. The sequence model is then implemented as extendable classes by an object oriented language. The simulator is applied to a commercial chip mounter to verify the usefulness of the method proposed.

• Journal of Computing Science and Engineering
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• v.9 no.1
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• pp.9-19
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• 2015

The most important challenge in the region-based abstraction method as an approach to compute the state space of time Petri Nets (TPNs) for model checking is that the method results in a huge number of regions, causing a state explosion problem. Thus, region-based abstraction methods are not appropriate for use in developing practical tools. To address this limitation, this paper applies a modification to the basic region abstraction method to be used specially for computing the state space of TPN models, so that the number of regions becomes smaller than that of the situations in which the current methods are applied. The proposed approach is based on the special features of TPN that helps us to construct suitable and small region graphs that preserve the time properties of TPN. To achieve this, we use TPN-TCTL as a timed extension of CTL for specifying a subset of properties in TPN models. Then, for model checking TPN-TCTL properties on TPN models, CTL model checking is used on TPN models by translating TPN-TCTL to the equivalent CTL. Finally, we compare our proposed method with the current region-based abstraction methods proposed for TPN models in terms of the size of the resulting region graph.