• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.119.3-119
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• 2001

When building a network-based real-time control system, a network-induced delay time should be surly considered for real time schedulability to be guaranteed. The network delay time on end-to-end communication has been analyzed theoretically and modeled mathematically from many previous works. There also exist any other delay element not considered before. In this paper, the remote feedback control system using the CAN protocol is proposed to control three axes´ manipulator arm and the application layer of CAN is modeled to analyze the delay elements defined by three types of time delay: Software delay time, Controller delay time, and Access delay time, in details. The analyzed results are used as an important component to determine PID gains of the proposed system. The effect of the delay time on the control performance is evaluated by com paring the response characteristics of the control system through simulation.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.639-641
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• 2002

In this paper, we proposed the multiple access control of RS232C Serial Communications protocol using collision sense method. The communications wires of data transmission and reception are tied together through the buffer each to connect to the multiple communication channels. The hardware interface and control program are designed to build the prototype system and the experimental multiple access communications network is built by multiple PC systems and the transfer completion rate results are shown.

• The Journal of the Korea Contents Association
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• v.22 no.9
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• pp.64-75
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• 2022

The method of accessing multiple control systems in the OT control network centered on operation technology uses the operator authentication technology of each control system. An example is ID/PW operator authentication technology. In this case, since the OT control network is composed of multiple control systems, operator authentication technology must be applied to each control system. Therefore, the operator must bear the inconvenience of having to manage authentication information for each control system he manages. To solve these problems, SSO technology is used in business-oriented IT networks. However, if this is introduced into the OT control network as it is, the characteristics of the limited size of the OT control network and rapid operator authentication are not reflected, so it cannot be seen as a realistic alternative. In this paper, a public key-based authentication mechanism was newly proposed as an operator authentication technology to solve this problem. In other words, an integrated public key certificate that applies equally to all control systems in the OT control network was issued and used to access all control systems, thereby simplifying the authentication information management and making access to the control system more efficient and secure.

• Proceedings of the IEEK Conference
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• 2007.07a
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• pp.167-168
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• 2007

It is necessary to control resource not only on access network also core network to guarantee the QoS certainly. This paper describes the RACF architecture and implements and analyzes the resource control system based on Y.2111, standardization documents of ITU-T SG13.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.73-76
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• 2005

The advanced information and communication technology gives vehicles another role of the third digital space, merging a physical space with a virtual space in a ubiquitous society. In the ubiquitous environment, the vehicle becomes a sensor node, which has a computing and communication capability in the digital space of wired and wireless network. An intelligent vehicle information system with a remote control and diagnosis is one of the future vehicle systems that we can expect in the ubiquitous environment. However, for the intelligent vehicle system, many issues such as vehicle mobility, in-vehicle communication, service platform and network convergence should be resolved. In this paper, an in-vehicle gateway is presented for an intelligent vehicle information system to make an access to heterogeneous networks. It gives an access to the server systems on the internet via CDMA-based hierarchical module architecture. Some experiments was made to find out how long it takes to communicate between a vehicle's intelligent information system and an external server in the various environment. The results show that the average response time amounts to 776ms at fixec place, 707ms at rural area and 910ms at urban area.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2419-2422
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• 2000

A distributed real-time system that is being used now is usually divided into three level : higher level, middle level, and lower level. The higher level network is usually called an information network, the middle level is called a control network, and the lower level is called a field network or a divice network. This dissertation suggests and implements a middle level network which is called PICNET-NP (Plant Implementation and Control Network for Nuclear Power Plant). PICNET-NP is based partly on IEEE 802.4 token-passing bus access methed and partly on IEEE 802.3 physical layer. For this purpose a new interface, a physical layer service translater, is introduced. A control network using this method is implemented and applied to a distributed real-time system.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.11a
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• pp.143-148
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• 1999

A distributed real-time system that is being wed now is usually divided into three level : higher level, middle level, and lower level. The higher level network is usually called an information network, the middle level is called a control network, and the lower level is called a field network or a divice network. This dissertation suggests and implements a middle level network which is called PICNET-NP (Plant Implementation and Control Network for Nuclear Power Plant). PICNET-NP is based partly on IEEE 802.4 token-passing bus access method and partly on IEEE 802.3 physical layer. For this purpose a new interface, a physical layer service translator, is introduced. A control network using this method is implemented and applied to a distributed real-time system.

• The KIPS Transactions:PartC
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• v.13C no.5 s.108
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• pp.567-574
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• 2006

VG-AnyLAN is a local area network standard developed by the IEEE 802.12 project. While preserving the frame format of IEEE 802.3, VG-AnyLAN adopts a new medium access control called Demand Priority where transmission requests of stations are arbitrated by a control hub in a round-robin manner. Unlike CSMA/CD which is the medium access control of IEEE 802.3, the Demand Priority, while providing the maximum bound on the packet delay, does not put the limit on the network segment size. In this paper, we analyze the delay and the channel utilization performances of the medium access control of IEEE 802.12 VG-AnyLAN. We develope an analytic model of the system under assumptions that each station generates traffic of the equal priority and that the packets are of fixed length. Using the analytic model, we obtain the recursive expression of the average channel utilization and the average access delay The numerical results obtained via analysis are compared to the simulation results of the system for a partial validation of our analysis.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.10
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• pp.1003-1008
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• 2016

Recently hospitals have divided into many divisions, specialized the medical service, and shown organic cooperation, all to provide patients with various and high quality medical service. They have also showed improvement in information protection by introducing an information protection system to regulate the access to patients' medical and personal information. The purpose of this paper is to present a case study to implement of a limited hospital medical information system that can regulate the access to medical information. For this, a router-based virtual network applying an ACL(: Access Control List) to regulate access to information was made using a packet tracer.

• Proceedings of the KIEE Conference
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• 2005.07d
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• pp.2771-2773
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• 2005

In network human-robot interaction, human can access services of a robot system through the network The communication is done by interacting with the distributed sensors via voice, gestures or by using user network access device such as computer, PDA. The service organization and exploration is very important for this distributed system. In this paper we propose a new agent-based framework to integrate partners of this distributed system together and help users to explore the service effectively without complicated configuration. Our system consists of several robots. users and distributed sensors. These partners are connected in a decentralized but centralized control system using agent-based technology. Several experiments are conducted successfully using our framework The experiments show that this framework is good in term of increasing the availability of the system, reducing the time users and robots needs to connect to the network at the same time. The framework also provides some coordination methods for the human robot interaction system.