• Journal of the Korea Society for Simulation
• /
• v.18 no.1
• /
• pp.9-16
• /
• 2009

Since a deadlock is a condition in which the excessive demand for the resources being used by others causes activities to stop, it is very important to detect and prevent a deadlock. About the deadlock detection analysis methods are may divide like as Siphon, DAPN and transitive matrix, but it's very difficult to evaluate the performance. Since DES (Discrete Event Systems) is NP-hard, and these detection and avoidance methods used various factors in each technique, it's made difficult to compare with each other's. In this paper, we are benchmarked these deadlock detection analyze methods based on the complexity, the detection time and the understanding after approached to one example.

• Journal of Institute of Control, Robotics and Systems
• /
• v.7 no.4
• /
• pp.344-350
• /
• 2001

In this paper, we are focused on the analysis of acyclic schedule for the determination of the opti-mal cycle time and minimization of work in process. Especially, this paper deals with the product ratio-driven cyclic scheduling problem in FMS with different products and ratio using the TPN(Time Petri Nets)un-folding.

• 전기의세계
• /
• v.43 no.3
• /
• pp.10-17
• /
• 1994

패트리네트는 시스템의 관계를 시작적으로 보여주어 시스템의 모델링을 쉽게 만든다. 시스템의 각 부분에 관한 정보를 가지고 전체와 부분에 대하여 하향식(top-down)과 상향식(bottom-up) 설계를 할 수 있게 해준다. 패트리네트는 그래프 표현이므로 FMS(flexible manufacturing systems)등과 같은 실시간 제어(real-time control)의 구현에 사용될 수 있으며 토큰 정보로부터 시스템의 각 부분의 상태를 실시간 감시(monitoring)할 수 있다. 패트리네트는 PLC(programmable logic controller)와 같이 여러 요소시스템(subsystem)을 순서대로 동작시키고 조정한다. 시스테메 대한 페트리네트 모델로부터 시뮬레이션(simulation)을 할 수 있고, 이로부터 성능 평가를 할 수 있다.

• Proceedings of the IEEK Conference
• /
• 2000.07b
• /
• pp.649-652
• /
• 2000

Beyond free choice net system this paper presents some liveness knowledge in asymmetric net system including necessary and sufficient condition for an asymmetric net system being live and having liveness monotonicity, and an algorithm, polynomial time complexity, for such deciding. Also two conjectures about system livenss are in the contribution.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.36 no.4B
• /
• pp.354-361
• /
• 2011

Increasing interest and technological advances in smart home has led to active research on context-awareness service and prediction algorithms such as Bayesian Networks, Tree-Dimensional Structures and Genetic prediction algorithms. Context-awareness service presents that providing automatic customized service regarding individual user's pattern surely helps users improve the quality of life. However, it is difficult to implement context-awareness service because the problems are that handling coincidence with context information and exceptional cases have to consider. To overcome this problem, we proposes an Intelligent Sequential Matching Algorithm(ISMA), models context-awareness service using Timed Petri-net(TPN) which is petri-net to have time factor. The example scenario illustrates the effectiveness of the Timed Petri-net model and our proposed algorithm improves average 4~6% than traditional in the accuracy and reliability of prediction.

• International Journal of Contents
• /
• v.6 no.4
• /
• pp.30-34
• /
• 2010

Effective job scheduling scheme is a crucial part of complex heterogeneous distributed systems. Gang scheduling is a scheduling algorithm for grid systems that schedules related grid jobs to run simultaneously on servers in different local sites. In this paper, we address grid jobs (gangs) schedule modeling using Stochastic reward nets (SRNs), which is concerned for static and dynamic scheduling policies. SRN is an extension of Stochastic Petri Net (SPN) and provides compact modeling facilities for system analysis. Threshold queue is adopted to smooth the variations of performance measures. System throughput and response time are compared and analyzed by giving reward measures in SRNs.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 2000.10a
• /
• pp.161-164
• /
• 2000

A cyclic shop is a production system that repeatedly produces identical sets of jobs, called minimal part sets, in the same loading and processing sequence. We consider a version of cyclic shop where the operations are processed and unloaded within time limits, so called a time window. We model the shop using an event graph model, a class of Petri nets. To represent the time window constraint, we introduce places with negative time delays. From the shop modeling graph, we develop a linear system model based on the max- plus algebra and characterize the conditions on the existence of a stable schedule.

• Journal of Information Technology Application
• /
• v.2 no.1
• /
• pp.113-137
• /
• 2000

Even though there is no doubt that ERP(Enterprise Resource Planing) system is a prevailing solution for integrating corporate information, many companies still hesitate adopting ERP system because of a great deal of cost including maintenance cost. In special, unless consulting knowledge that is infused into process reengineering phase or adequately embedded in customized ERP system is upgraded on time, then we cannot guarantee the optimality of system performance. Hence, this paper aims to construct an ERP system that adapts itself to environmental changes that are issued by database and users. To do so, we adopt intelligent agent technology and Petri net theory. The agents autonomously cooperate each other to investigate databases and to find any exceptional changes and analyze how the changes will affect ERP performance. The dynamics of the agents are represented as Petri nets. The newly proposed ERP system is to make corresponding BPR processes maintain optimality. To show the feasibility of the proposed ERP maintenance system, logistics component is described as an illustrative example.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.14 no.5
• /
• pp.511-520
• /
• 1989

Generally, Intelliget link is made of drawing picture that is amalgated in two conception of communication and processing. This is a new system of information transmission having fuction being able to handle een though the former information transmission can not be possible. That Intelligent link is to say that function of each segment by working software can be anailable at general purposed pipeline processing system, general purpose pipeline have a different working time in function of segmant, work asynchronizing pipeline. in the papers, graphic design is easy to understand the sense of sight model by Petri Net that is simple regulation. it can translate into working of asynchronzing pipeline by working of calculator of simulation.

• Journal of Korean Society for Quality Management
• /
• v.27 no.2
• /
• pp.251-262
• /
• 1999

In the automated manufacturing systems, the problem regarding how to make production activities flexible is even more important and critical than that regarding how to product large quantities, and the more flexible, if possible, the manufacturing system is, the more competitiveness and profitable factors it gets. This research, therefore, concentrated on establishing the flexibility and evaluating performance on the manufacturing system, operational flexibility is considered because of enabling the manufacturing system to get both the improvement of production rate and the adaptive ability of environment changes. For it, we used the analytical tool, GSPNs, which is a kind of timed Petri-Nets. GSPNs is competent enough to consider practical situations just like operation priorities, machine failure, randomness, concurrency and so on. Through the GSPNs analysis, it is confirmed that in the manufacturing system with operational flexibility is compatible with the traditional performances such as production rate or mean waiting time.