• Journal of Korean Society of Transportation
• /
• v.12 no.3
• /
• pp.49-64
• /
• 1994

The development of a mathematical modular framework based on Petri Network theory to model a traffic network is the subject of this paper. Traffic intersections are the primitive elements of a transportation network and are characterized as event driven and asynchronous systems. Petri network have been utilized to model these discrete event systems; further analysis of their structure can reveal information relevant to the concurrency, parallelism, synchronization, and deadlock avoidance issuse. The Petri-net based model of a generic traffic junction is presented. These modular networks are effective in synchronizing their components and can be used for modeling purposes of an asynchronous large scale transportation system. The derived model is suitable for simulations on a multiprocessor computer since its program execution safety is secured. The software pseudocode for simulating a transportation network model on a multiprocessor system is presented.

• Journal of Korea Spatial Information System Society
• /
• v.12 no.1
• /
• pp.28-36
• /
• 2010

Some context is characterized by a single event in computing environment, but many other contexts are determined by a lot of things which occur with a space and a time. The Realtime Sensor Network context-awareness service that interacts with the physical space can have property such as time. A methodology that is specified the relationship between the contexts and the service needs to be developed to Realtime context-awareness deal with spatio-temporal. In this paper, we propose an approach which should include spatio-temporal property in the context model, and verify its effectiveness using enhanced Petri-Net. The context-awareness service modeling of Realtime Sensor Network is discussed the properties of model such as basic Petri-Net, patterned Petri-Net, or Spatio-temporal Petri-Net. The proposed methodology demonstrated using an example that is SAEMANGUEM warming watching system. The use of Spatio-temporal Petri-Net will contribute not only to develop the application but also to model the spatio-temporal context awareness.

• Journal of Institute of Control, Robotics and Systems
• /
• v.2 no.3
• /
• pp.209-219
• /
• 1996

Fieldbus provides a real-time data communication among field devices in the process control and manufacturing automation systems. In this paper, a Petri Net model of the 1993 draft of IEC/ISA fieldbus which is proposed as an international standard of fieldbus network is developed. Based on the Petri Net model, discrete-event simulation model of IEC/ISA fieldbus network is developed. This paper evaluates the network induced delay in the data link layer of IEC/ISA fieldbus using the simulation model. In addition, an integrated discrete-event/continuous-time simulation model of fieldbus system and distributed control system is developed. This paper investigates the real-time data processing capability of IEC/ISA fieldbus and the effect of network-induced delay to the performance of control system.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1992.04b
• /
• pp.436-443
• /
• 1992

Presented in the paper is a systematic approach to constructing a Petri net model of FAS (flexible assembly system). Petri net is widely used in modeling automated manufacturing systems. But, it found to be very difficult for an FA engineer to build a correct model of an FAS with Petri net symbols (ie, place, transition, and token) from the beginning. An automated manufacturing system in general is built from a set of "standard" hardware components. An FAS in particular is usually composed of assembly robots, work tables, conveyor lines, buffer storages, part feeders, etc. In the proposed modeling scheme, each type of standard resources is represented as a standard "module" which is a sub Petri net. Then, the model of a FAS can be conveniently constructed using the predefined modules the same way the FAS itself is built from the standard components. The network representation of a FAS is termed a JR-net (job resource relation net) which is easy to construct. This JR net is then mechanically converted to a formal Petri net (to simulate the behavior of the FAS). The proposed modeling scheme may easily be extended to the modeling of other types of automated manufacturing systems such as FMS and AS/RS.ch as FMS and AS/RS.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.10 no.2
• /
• pp.107-114
• /
• 2007

This paper describes the Petri Net(PN) model for reliability analysis of fault-tolerant dual Ethernet which Is applied in Naval Combat System. The network for Naval Combat System performs failure detection and auto path recovery by handling redundant path in case of temporary link failure. After studying the behavior of this kind of network, the reliability analysis model is proposed using stochastic Petri Net and continuous-time Markov chains. Finally, the numerical result is analyzed according to changing the failure rate and the recover rate of link.

• International Journal of Computer Science & Network Security
• /
• v.22 no.2
• /
• pp.413-423
• /
• 2022

The NHIS provides free or highly subsidized healthcare to all people by providing financial fortification. However, the financial sustainability of the scheme is threatened by numerous factors. Therefore, this work sought to provide a solution to process claims intelligently. The provided Petri net model demonstrated successful data flow among the various participant. For efficiency, scalability, and performance two main subsystems were modelled and integrated - data input and claims processing subsystems. We provided smart claims processing algorithm that has a simple and efficient error detection method. The complexity of the main algorithm is good but that of the error detection is excellent when compared to literature. Performance indicates that the model output is reachable from input and the token delivery rate is promising.

• The KIPS Transactions:PartC
• /
• v.12C no.4 s.100
• /
• pp.559-570
• /
• 2005

ECN is accurate in determining traffic congestion since it explicitly notifies the incipient congestion. Therefore, ECN method has been thoroughly studied in the field of wireless TCP. This paper introduces a formula to find the optimal threshold for ECN marking. We have implemented a Petri net model of 'TCP with ECN strategy' and performed simulations on it in order to verify the validity of the formula. We have also introduced ideas of applying the formula in practice. The primary contribution of this paper is proposing a formula to find the optimal threshold for ECN marking. However, introducing the Petri net model of 'TCP with ECN strategy' is no less valuable contribution because it can be helpfully used by the researchers in studying network protocols. We have built the Petri net model by modifying the existing Petri net model of TCP. In order to add ECN strategy to the existing model, we have mainly modified the network part. We have also modified sender part and receiver part as well.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.38C no.12
• /
• pp.1170-1178
• /
• 2013

Thanks to various benefits, low-cost real-time communication networks so called fieldbus have been widely used in many industrial applications including military systems, such as aircrafts, submarines, and robots. This paper presents a reliability analysis of dual-channel CAN(Controller Area Network) fieldbus which is used for controlling various equipment of submarine combat system. A submarine combat system playing a critical role to the success of missions and survivability consists of various devices including sensors/actuators and computers. Since a communication network for submarine combat system must satisfy an extremely high level of reliability, a dual channel technique is commonly adopted. In this paper, a Petri Net based reliability model for dual-channel CAN is discussed. A reliability model called generalized stochastic Petri Nets (GSPN) is built by utilizing the information on physical faults with CAN. The effectiveness of the proposed model is analyzed in terms of unreliability with respect to failure rate and repair rate.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.9
• /
• pp.1717-1722
• /
• 2016

Availability, one of the important metrics used to assess the performance of network system, is defined as the probability that a system is operational at a given point in time under a given set of environmental conditions. To improve the availability of the network service, the redundancy models and the rejuvenation schemes are the effective schemes to be typically used. In this paper, we analyse the effect of 2N redundancy model and/or rejuvenation scheme on the availability of network service. The 2N redundancy model consists of one active and one standby component and the performance of time-based rejuvenation scheme mainly depends on its rejuvenation period. We design stochastic reward net model for the 2N redundancy model with time-based rejuvenation scheme and analyse the service availability of the model using stochastic Petri net package. We provide some numerical examples of the service availability, which shows that the system with rejuvenation has higher availability than the system without rejuvenation.

• International Journal of Contents
• /
• v.5 no.4
• /
• pp.88-93
• /
• 2009

It is important for communication networks to possess the capability to overcome failures and provide survivable services. We address modeling and analysis of performability affected by both performance and availability of system components for a token ring network under failure and repair conditions. Stochastic reward nets (SRN) is an extension of stochastic Petri nets and provides compact modeling facilities for system analysis. In this paper, hierarchical SRN modeling techniques are used to overcome state largeness problem. The upper level model is used to compute availability and the lower level model captures the performance. And Normalized Throughput Loss (NTL) is obtained for the composite ring network for each node failures occurrence as a performability measure. One of the key contributions of this paper constitutes the Petri nets modeling techniques instead of complicate numerical analysis of Markov chains and easy way of performability analysis for a token ring network under SRN reward concepts.