• 한국정보컨버전스학회:학술대회논문집
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• 한국정보컨버전스학회 2008년도 International conference on information convergence
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• pp.117-120
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• 2008

If the management through the center server is unnecessary and JXTA is connected to a network, a communication with any kind of devices or some device is possible. And features that a communication with heterogeneous P2P systems is possible have. The important module of the designed Data exchange system an interworking between the P2P system which it is made we used API and the each other different protocol the possible data for replacement Data exchange system were designed this kind of a feature was to the utmost utilized may account for the XML Parser Component(XPC) which we use it parses the or about a request and the generated request, and the structure of the XML Making Component(XMC) which we use in generating the inappropriate a request and response.

• 한국컴퓨터산업학회논문지
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• 제2권10호
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• pp.1269-1284
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• 2001

SSL은 인터넷의 표준 프로토콜인 TCP/IP 트래픽의 암호화를 위해, 기밀성과 인증, 그리고 데이터 무결성을 제공하는 프로토콜이다. 또한 SSL은 인터넷 클라이언트/서버 통신 보안을 위해, 여러 어플리케이션 계층에 적용할 수 있는 연결 중심형 메커니즘을 제공하기 위한 것을 목적으로 한다. 넷스케이프사에 의해 개발된 SSL은 현재 모든 클라이언트의 브라우저와 보안을 제공하는 서버에 의해 지원된다. 현재 SSL의 버전은 3.0이며, 1999년 1월 IETF의 TLS 작업 그룹이 TLS v1.0 명세서를 발표하였다. SSL은 여러 버전을 거치면서, 많은 취약성을 드러내었다. SSL과 TLS는 핸드쉐이크 프로토콜을 이용하여 암호학적 파라미터들을 교환하여 비밀키를 생성하는데, 이 과정에서 많은 공격이 취해질 수 있으며, 또한 레코드 프로토콜에서도 공격이 일어날 수 있다. 본 논문에서는 SSL 프로토콜을 분석하고, TLS와의 차이점을 비교하였으며, 현재 알려진 공격들을 자세히 분석하여, 개발자들이 구현 시 주의해야 할 것들을 제시하였다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.511-514
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• 2002

In may automated systems such as manufacturing systems and process plants, an industrial network or 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 TTR and the traffic characteristics are given. The results of this model is compared to those from experiments to assess the model's validity.

• 한국정밀공학회지
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• 제16권3호통권96호
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• pp.91-102
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• 1999

Fieldbus provides real-time data communication among field devices in the manufacturing automation and process control systems. In this study, an experimental model of fieldbus-based manufacturing automation system is developed. Experimental model consists of two robots, two conveyor belts, NC machine, PLC, sensors and operator station. These machines are interconnected into the Profibus network, and exchange their data through the services provided by FMS(Fieldbus Message Specification), which is the application layer protocol of Profibus. The experimental model is used to measure the network-induced delay of variable and file data transmitted through FMS services. Network-induced delays are collected and analyzed on each sublayer of Profibus protocol stack. The results obtained from the experiment of this study can be effectively utilized when fieldbus is implemented on the practical manufacturing automation systems.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2003년도 추계학술대회 논문집(III)
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• pp.204-209
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• 2003

Recently, The TCN(Train Communication Network} as the distributed control systems for electric vehicles, which is the international standard of the intra vehicle communication, actively recognizes variations and supports reconfiguration of the train network when a vehicle is separated or recombined. The technique of reconfiguration to take variety and interoperability of a vehicle constitution is used when the vehicle constitution is changed. At the time, each node making up vehicle network shares the information about the variation of vehicle constitutions and the state of nodes. In the hierarchical TCN structure, an exchange of data becomes available as a work to transmit information between components is performed at the node playing a role of gateway. This paper proposes a protocol to transmit the information of the train reconfiguration. The protocol gives an application to renew a list for transmitting information and to perform the transmission that can guarantee periodic and non-periodic data transmission between nodes when the network nodes changed by a variation of the network state are reconfigured. If use this protocol, can use functions that are offered in the electric railcar at the same time that composition of vehicles is completed without delay. And when driver of the electric railcar inspect before running of vehicles, can confirm state of vehicles visually through monitor in driver's room.

• Journal of Multimedia Information System
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• 제5권3호
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• pp.163-170
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• 2018

We developed a multicast communication packet radio protocol using a time-sharing tablet system ("wireless token ring") to achieve the efficient exchange of files among packet radio terminals attached to swans. This paper provides an overview of the system and the protocol of the packet communications. The packet device forming the main part of the transceiver developed is the Texas Instruments CC2500. This device consists of one call-up channel and one data transmission channel and could improve error frame correction using FEC (forward error correction) with 34.8 kbps MSK and receiving power of at least -64 dBm (output 1 dBm at distance of 200 m using 3 dBi antenna). A time-sharing framework was determined for the wireless token ring using call sign ordinals to prevent transmission right loss. Tests using eight stations showed that resend requests with the ARQ (automatic repeat request) system are more frequent for a receiving power supply of -62 dBm or less. A wireless token ring system with fixed transmission times is more effective. This communication protocol is useful in cases in which frequency resources are limited; the energy consumed is not dependent on the transmission environment (preset transmission times); multiple terminals are concentrated in a small area; and information (position data and vital data) is shared among terminals under circumstances in which direct communication between a terminal and the center is not possible. The method allows epidemiological predictions of avian influenza infection routes based on vital data and relationships among individual birds based on the network topology recorded by individual terminals. This communication protocol is also expected to have applications in the formation of multiple in vivo micromachines or terminals that are inserted into living organisms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제6권6호
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• pp.1689-1706
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• 2012

The preservation of temporal dependencies among a group of processes that exchange continuous media at runtime is a key issue for emerging mobile distributed systems (MDS), such as monitoring of biosignals and interactive multiuser games. Although several works are oriented to satisfy temporal dependencies, most of them are not suitable for MDSs. In general, an MDS is characterized by the absence of global references (e.g. shared memory and wall clock), host mobility, limited processing and storage capabilities in mobile hosts, and limited bandwidth on wireless communication channels. This paper proposes an asymmetric synchronization protocol to be used at runtime in an MDS without using a common reference. One main aspect of our synchronization protocol is that it translates temporal constraints to causal dependencies of the continuous media data as seen by the mobile hosts. We simulate the protocol by considering a cellular network environment and by using MPEG-4 encoders. The simulation results show that our protocol is effective in reducing the synchronization error. In addition, the protocol is efficient in terms of processing and storage costs at the mobile devices, as well as in the overhead attached per message across the wired and wireless channels.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제11권4호
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• pp.312-333
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• 2005

SIP(Session Initiation Protocol)은 VoIP(Iroice over IP)와 같은 인터넷 멀티미디어 통신 시스템의 세션 제어 프로토콜로 제안되었으며 많은 표준안에서 채택하고 있다. SIP는 다양한 형태의 오디오와 비디오 형식과 품질이 보장된 실시간 데이터 전송을 지원하기 위해 복잡한 세션 제어 단계를 갖는다. 그러나 지금까지의 프로토콜 분석기는 SIP 기반 멀티미디어 통신 시스템에서 발생되는 트래픽을 상세하게 분석해주지 못하고 있다 이에 본 논문에서는 SIP 기반의 멀티미디어 통신 시스템의 세션 설정 단계에서 데이터 교환 및 세션 변경에 따른 세부 정보를 분석하고 진단할 수 있는 도구로 새로운 프로토콜 분석기를 설계하고 구현한다. 제안된 프로토콜 분석기는 STAT(SIP based Traffic Analysis Tool)이라고 부르며 범용성과 확장성이 있도록 PC Windows에서 사용 가능한 소프트웨어로 구현되었다. STAT는 이더넷의 특징인 동보 기능을 이용하여 저수준 패킷을 수집하여 분석함으로써 SIP 기반 통신 시스템에 직접적인 영향 없이 세션 연결 상태와 실시간 트래픽 모니터링 정보를 제공한다. 따라서 본 논문에서 구현한 STAT는 SIP 기반 멀티미디어 통신 시스템의 개발 및 관리 도구로 활용될 수 있다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(1)
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• pp.253-256
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• 2001

This paper describes a high speed MAC(Media Access Control) function chip for IEEE 802.11 MAC layer protocol. The MAC chip has control registers and interrupt scheme for interface with CPU and deals with transmission/reception of data as a unit of frame. The developed MAC chip is composed of protocol control block, transmission block, and reception block which supports the BCF function in IEEE 802.11 specification. The test suite which is adopted in order to verify operation of the MAC chip includes various functions, such as RTS-CTS frame exchange procedure, correct IFS(Inter Frame Space)timing, access procedure, random backoff procedure, retransmission procedure, fragmented frame transmission/reception procedure, duplicate reception frame detection, NAV(Network Allocation Vector), reception error processing, broadcast frame transmission/reception procedure, beacon frame transmission/reception procedure, and transmission/reception FIEO operation. By using this technique, it is possible to reduce the load of CPU and firmware size in high speed wireless LAN system.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제15권7호
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• pp.495-499
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• 2009

위치 기반 라우팅 프로토콜들에 기본 가정인 이웃 노드들간의 주기적인 위치 정보 교환은 다음 두 가지 문제를 갖는다: (1) 데이터 전달이 없는 지역에 노드들의 불필요한 에너지 소비와 (2) 데이터 전달 시점에 이웃 노드 위치 정보의 부정확성. 따라서, 본 논문은 이동 무선 센서 네트워크에서 on-demand 위치 기반 라우팅 프로토콜을 제안한다. 제안 방안에서 송신 노드는 데이터 전달 시점에 필요한 이웃 노드들만의 위치 정보를 획득하고 그 노드들의 이동성을 고려하여 그 이웃 노드들 중에 가장 적합한 노드를 목적지 노드까지 데이터 전달을 위한 수신 노드를 결정한다. 시뮬레이션 결과는 제안 방안이 기존의 위치 기반 라우팅 프로토콜보다 더 효율적임을 보인다.