• Journal of Institute of Control, Robotics and Systems
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• v.13 no.6
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• pp.596-602
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• 2007

Recently, many ECUs(Electronic Control Units) have been used to enhance the vehicle safety, which leads to a distributed real-time control system. The distributed real-time control system requires to reduce the network delay for dependable real-time performance. There are two different paradigms by which a network protocol operates: event-triggered and time-triggered. This paper focuses on implementation of a time-triggered protocol. i.e. TTP/C(Time-Triggered Protocol/class C). This paper presents a design method of TTP control network and performance evaluation of distributed real-time control system using TTP protocol.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.4
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• pp.692-700
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• 2012

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and Wireless USB. In this paper, firstly, the fair SoQ-based Distributed Reservation Protocol (DRP) for D-MAC is analyzed. And a novel SoQ-based relay transmission protocol is proposed to overcome DRP conflicts fast. In the proposed protocol, each device executes the Satisfaction of QoS (SoQ) time slot allocation algorithm independently. And, in order to give the loser device due to DRP conflicts another chance to maintain QoS resources, the proposed relay transmission protocol helps the device reserve another indirect link maintaining the required QoS resources via a relay node.

• Journal of the Korea Society of Computer and Information
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• v.21 no.8
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• pp.41-48
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• 2016

In this paper, we propose an election protocol based on mobile ad-hoc network. In distributed systems, a group of computer should continue to do cooperation in order to finish some jobs. In such a system, an election protocol is especially practical and important elements to provide processes in a group with a consistent common knowledge about the membership of the group. Whenever a membership change occurs, processes should agree on which of them should do to accomplish an unfinished job or begins a new job. The problem of electing a leader is very same with the agreeing common predicate in a distributed system such as the consensus problem. Based on the termination detection protocol that is traditional one in asynchronous distributed systems, we present the new election protocol in distributed systems that are based on MANET, i.e. mobile ad hoc network.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.582-585
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• 2001

Requirements for device networks differ greatly from those of data(business) networks. Consequently, any control network technology which uses a fieldbus protocol is, in general, different from IP network protocol TCP/IP. One needs to integrate fieldbus protocol and TCP/IP to realize distributed control over IP network or internet. This paper suggests a basic concept that can be applied to distributed control over IP network or internet. Specifically, LonWorks technology that uses LonTalk protocol is reviewed as device network. LonWorks technology provides networked intelligent I/O and controllers which make it a powerful, expandable solution. It is also addressed that many hardwired PLCs can be replaced by LonWorks devices. Connecting these remote LonWorks networks to the Internet can provide a powerful, integrated, distributed control system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.3
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• pp.460-469
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• 2012

The WiMedia Alliance has specified a Distributed Medium Access Control (D-MAC) protocol based on UWB for high speed wireless home networks and WPANs. In this paper, we propose a novel cooperative communication protocol adaptive to current UWB link transmission rate. The proposed cooperative communication protocol has compatibility with current WiMedia D-MAC and Wireless USB standard and is executed at each device according to a Relay Node Selection (RNS) criterion.

• Journal of the Korea Society for Simulation
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• v.5 no.1
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• pp.81-90
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• 1996

In this paper, we propose a new events ordering mechanism for the optimistic distributed simulation of DEVS models. To simulate DEVS models in a distributed environment, a synchronization protocol is required for correct simulation. Time Warp is the most well-known optimistic synchronization protocol for distributed simulation. However, employing the Time Warp protocol in distributed simulation of DEVS models incurs events ordering problem due to the semantic difference between Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.Time Warp and DEVS, Thus, to resolve such semantic difference, we devise the time-and-priority-stamp and $\varepsilon$ -delay schemes. The proposed schemes can order simultaneous events correctly in Time Warp-based distributed simulation of DEVS models.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.4
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• pp.371-376
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• 2004

Distributed Network Protocol Version 3.0 (DNP3.0) is the communication protocol developed for the interoperability between a RTU and a central control station of SCADA in the power utility industry. In this paper DNP3.0 is implemented by using HDL with FPGA and C program on Hitachi H8/532 processor. DNP3.0 is implemented from physical layer to network layer in hardware level to reduce the computing load on a CPU. Finally, the ASIC for DNP3.0 has been manufactured from Hynix Semiconductor. The commercial feasibility of the hardware through the communication test with ASE2000 and DNP Master Simulator is performed. The developed protocol becomes one of IP, and can be used to implement SoC for the terminal device in SCADA systems. Also, the result can be applicable to various industrial controllers because it is implemented in HDL.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.52 no.3
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• pp.95-99
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• 2003

In this paper, the power system automation based on CAN communication protocol is introduced. Along with digitalization of electrical device, the various on-line services such as remote control, remote monitoring, remote parameter setting, fault data recording and remote diagnostic have been realized and become available. Therefore, it is necessary for those electrical devices to have real-time and reliable communication protocols. Author proposes DNPC(Distributed Network Protocol with CAN) which is proper to the power system SCADA (Supervisory Control And Data Acquisition) and DCS (Distributed Control System). The physical and datalink layer of DNPC protocol consists of the CAN2.0B which has the real-time characteristics and powerful error control scheme. As the transport and application layer, DNP3.0 is adopted because of its flexibility and compatible feature. Using the DNPC protocol, the power system automation is realized.

• The Transactions of the Korea Information Processing Society
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• v.3 no.4
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• pp.926-937
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• 1996

A graph traversal technique is a certain pattern of visiting nodes of a graph. Many special traversal techniques have been applied to solve graph related problems. For example, the depth first search technique has been used for finding strongly onnected components of a directed graph or biconnected components of a general graph. The distributed protocol to implement his depth first search technique on the distributed network can be divided into a fixed topology problem where there is no topological change and a dynamic topology problem which has some topological changes. Therefore, in this paper, we present a more efficient distributed depth first search protocol with fixed topology and a resilient distributed depth first search protocol where there are topological changes for the distributed network. Also, we analysed the message and time complexity of the presented protocols and showed the improved results than the complexities of the other distributed depth first search protocols.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.3
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• pp.526-534
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• 2014

In this paper, for the WiMedia Distributed Medium Access Control (D-MAC) protocol based on UWB. performance degradation due to the Distributed Reservation Protocol (DRP) conflict problem caused by devices' mobility is analyzed. And a DRP relay protocol and a DRP conflict resolution (CR) are proposed to overcome the performance degradation at DRP conflicts. In order to give the loser device at DRP conflicts a chance to maintain resources, the proposed DRP relay protocol executed at each device helps the loser device reserve an indirect link maintaining the required resources via a relay node. Simulation results considering the mobile environment have indicated that the DRP relay combined with the CR prevent the throughput decrease even though mobility of devices increases.