• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.54.3-54
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• 2002

$\textbullet$ Introduction $\textbullet$ Token Passing Protocol : Profibus-FMS $\textbullet$ Performance Model of Profibus Token Passing Protocol $\textbullet$ Calculation of Communication Delay in Performance Model $\textbullet$ Summaries and Conclusions

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.181-184
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• 2003

Recently, the fieldbus becomes an indispensable component for many automated systems. In the fieldbus system, realtime data containing sensor values and control commands has a tendency to rapidly lose its value as time elapses after its creation. In order to deliver these data in time, the fieldbus network should be designed to have short delay compared to the maximum allowable delay. Because the communication delay is affected by performance parameters such as target rotation timer of token passing protocol, it is necessary to select proper parameter settings to satisfy the real-time requirement for communication delay. This paper presents the timer selection method for Profibus token passing networks using genetic algorithm (GA) to meet the delay requirements.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.118-118
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• 2000

This paper suggests the methodology to guarantee the rea1-time service over Ethernet and TCP/IP and to solve the problems such as re-transmission due to collision and platform-transparency and independence. This paper proposes a new mechanism called Real-time Ethernet protocol combined the centralized medium control mechanism with the token passing mechanism. The centralized medium control mechanism is used to get the token, the right to transmit the data, and the token passing mechanism is used to return the token to the token controller and to transmit data within the specified time interval. The proposed Real-Time Ethernet Protocol is based on Java and Java RMI(Remote Method Invocation). The presented protocol is believed to work enough in real-time applications considering latency occurred due to the Java RMI, which is less small than data transmission time.

• 대한전자공학회논문지
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• 제26권3호
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• pp.22-31
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• 1989

본 논문에서는 프로토콜의 시뮬레이션 모델을 통하여 IEEE 802.4 토큰 패싱 버스 프로토콜의 성능을 분석하였다. 정상상태 뿐아니라 초기상태, 과도상태, fault recovery 상태에서 프로토콜의 성능을 분석하기위해 프로토콜의 기능을 다섯개의 프로세스로 나누어 구성하였으며 각 프로세스는 프로토콜에서 정의된 피라미터들에 따라 프로토콜의 동작을 실제적으로 수행한다. 프로토콜의 시뮬레이션을 통한 연구로부터 망의 성능을 좌우하는 프로토콜 피라미터들을 알 수 있었으며 priority가 구현된 경우 토큰에 대한 피라미터 값의 선택이 이 프로토콜의적절한 사용을 위하여 매우 중요함을 알 수 있었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.470-473
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• 2002

Most networks for automation are tuned to an expected traffic at their design stage. During their actual operations, however, the networks experience considerable changes in traffic from time to time. These traffic changes caused by common events like machine failure and production schedule change may adversely affect the network performance and, in turn, the performance of the connected devices. This paper presents communication delay model for Profibus token passing protocol, and introduces TTR selection methods to maintain a uniform level of network performance at all stations under changing network traffic.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.741-744
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• 1990

This paper deals with the implementation of the IEEE 802.4 token passing bus protocol which is the world standard for LAN protocol. We are design station adaptor using MC68824 for data link layer, MC68194 for physical layer, and implemented by IEEE 802.4 and 802.2 type 3. We made three station adaptor and its performance is experimented.

• Journal of Information Processing Systems
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• 제10권1호
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• pp.36-54
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• 2014

Resource sharing is a major advantage of distributed computing. However, a distributed computing system may have some physical or virtual resource that may be accessible by a single process at a time. The mutual exclusion issue is to ensure that no more than one process at a time is allowed to access some shared resource. The article proposes a token-based mutual exclusion algorithm for the clustered mobile ad hoc networks (MANETs). The mechanism that is adapted to handle token passing at the inter-cluster level is different from that at the intra-cluster level. It makes our algorithm message efficient and thus suitable for MANETs. In the interest of efficiency, we implemented a centralized token passing scheme at the intra-cluster level. The centralized schemes are inherently failure prone. Thus, we have presented an intra-cluster token passing scheme that is able to tolerate a failure. In order to enhance reliability, we applied a distributed token circulation scheme at the inter-cluster level. More importantly, the message complexity of the proposed algorithm is independent of N, which is the total number of nodes in the system. Also, under a heavy load, it turns out to be inversely proportional to n, which is the (average) number of nodes per each cluster. We substantiated our claim with the correctness proof, complexity analysis, and simulation results. In the end, we present a simple approach to make our protocol fault tolerant.

• 제어로봇시스템학회논문지
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• 제9권12호
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• pp.1055-1064
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• 2003

In many automated systems, such as manufacturing systems and process plants, a fieldbus is a very important component for the exchange of various and sometimes crucial information. Some of the information has a tendency to rapidly lose its value as time elapses after its creation. Such information or data is called real-time data that includes sensor values and control commands. In order to deliver these data in time, the fieldbus network should be tailored to have short delay with respect to the individual time limit of various data. Fine-tuning the network for a given traffic requires the knowledge on the relationship between the protocol parameters such as timer values and the performance measure such as network delay. This paper presents a mathematical performance model to calculate communication delays of the Profibus-FMS network when the timer value and the traffic characteristics are given.

• 한국정보과학회논문지:시스템및이론
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• 제29권3호
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• pp.125-133
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• 2002

본 논문은 대규모 분산시스템에서 전체 순서화를 유지하는 방송통신 프로토콜을 제안한다. 기존의 토큰기반 방송통신 프로토콜과는 달리 제안된 프로토콜에서 토큰은 방송도메인을 구성하는 링을 묵시적으로 회전하지는 않는다. 대신에 토큰 전송을 위한 세 개의 메시지를 사용한다. 토큰은 방송메시지를 위한 순서번호 정보를 갖고 있으며, 오직 토큰을 소유한 노드만이 방송메시지를 전송할 수 있다. 방송메시지를 전송하려 하는 노드는 토큰을 소유한 토큰노드로 토큰요청메시지를 보내고, 토큰노드는 요청한 노드에게 토큰을 전송한다. 토큰을 요청한 노드가 토큰을 소유하게 되면 토큰의 순서정보를 이용하여 방송메시지를 전송한다. 이 메시지를 수신한 모든 노드는 토큰노드가 변경되었음을 인식하게 되고, 새로운 토큰노드로 토큰을 요청하게 된다. 그러나, 새로운 토큰 노드로부터 방송메시지를 수신하기 전에 과거의 토큰노드로 토큰요청메시지를 전송하는 노드가 존재할 수 있다. 이 문제를 해결하기 위해 제안된 프로토콜은 과거 토큰노드가 새로운 토큰노드에게 다음 토큰요청노드를 알리는 메시지를 사용한다. 시뮬레이션 결과를 통해 기존의 방송통신 프로토콜보다 제안된 프로토콜이 대규모 분산시스템에서 더욱 효율적이라는 것을 알 수 있다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.52.3-52
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• 2001

There are some problems to implement a realtime network system with Ethernet because the MAC(Medium Access Control) of Ethernet uses a CSMA/CD protocol, which introduces unexpected delays. In this paper, we designed a method to solve problems due to the Ethernet MAC. This method introduces a pseudo-MAC in application layer to support the real-time feature. So the presented method doesn´t need any modifications of protocols such as UDP/IP/MAC. The presented pseudo-MAC is based on both a token passing protocol and a publisher-subscriber protocol. The suggested realtime protocol is implemented and tested practically in a local area network. The proposed real-time network consists of a token controller node and general nodes.