• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.33 no.8B
• /
• pp.657-666
• /
• 2008

The intersection collision avoidance service among various telematics application services is regarded as one of the most critical services with regard to safety. In such safety applications, real-time, correct transmission of service is required. In this paper, we study on efficient infrastructure architecture for intersection collision avoidance using a cooperative mechanism between vehicles and wireless infrastructure. In particular, we propose an infrastructure, called CISN (Cooperative Infrastructure associated with Sensor Networks), in which proper numbers of sensor nodes are deployed on each road, surrounding the intersection. In the proposed architecture, overall service performance is influenced by various parameters consisting of the infrastructure, such as the number of deployed sensor nodes, radio range and broadcast interval of base station, and so on. In order to test the feasibility of the CISN model in advance, and to evaluate the correctness and real-time transmission ability, an intersection sensor deployment simulator is developed. Through various simulations on several environments, we identify optimal points of some critical parameters to build the most desirable CISN.

• Proceedings of the KSRS Conference
• /
• 2004.10a
• /
• pp.283-286
• /
• 2004

This paper refers and implements XML Web services, which supports networked interchanges of moving object information. XML Web services are expected to be fundamental building blocks in the move to distributed computing on the Internet. As an interchange format, GML encodes semantics, syntax, and schema of geospatial and geoprocessing-related information resources. It can give great benefits to utilize raw data easily as an XML encoding format does. This paper proposes a full coverage of interoperable location trajectory services consisting of 3 independent modules: a moving object database, a data processing server, and a web services interface module. For communications, SOAP protocols and WSDL documents are used, which can guarantee an interoperability of a system regardless of different platforms and service channels. This paper also designs a GML data format that represents location information of probe cars.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.31 no.1B
• /
• pp.39-45
• /
• 2006

In this paper, existing technology that uses broadcasting and multicasting IP addrsses at the wireless access network, based on Internet as a core network, is upgraded. By employing broadcasting service request by receivers, convergence of multicasting and broadcasting, and lower level filtering of broadcast data, the load and traffic of network, server, base station, and receiver is substantially reduced. The technology proposed in this paper could be useful for general broadcasting services, and especially optimum for LBS and Telematics services.

• Journal of Communications and Networks
• /
• v.5 no.3
• /
• pp.202-214
• /
• 2003

The central challenge in the design of ad-hoc networks is the development of dynamic routing protocol that efficiently finds route between mobile nodes. Several routing protocols such as DSR, AODV and DSDV have been proposed in the literature to facilitate communication in such dynamically changing network topology. In this paper, a Node Transition Probability (NTP) based routing algorithm, which determines stable routes using the received power from all other neighboring nodes is proposed. NTP based routing algorithm is designed and implemented using Global Mobile Simulator (GloMoSim), a scalable network simulator. The performance of this routing algorithm is studied for various mobility models and throughput, control overhead, average end-to-end delay, and percentage of packet dropped are compared with the existing routing protocols. This algorithm shows acceptable performance under all mobility conditions. The results show that this algorithm maximizes the bandwidth utilization during heavy traffic with lesser overhead.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.29 no.3A
• /
• pp.288-292
• /
• 2004

Recently the application area of wireless LAN has been increased, rapidly. The application area was limited in indoor, but as the data throughput and performance of wireless LAN becomes better the application is to extend to the Internet connection and wireless bridge in outdoor. In this paper, the data throughput of wireless LAN in mobile environment is measured, and the usability of wireless LAN for ITS, Telematics, and LBS is confirmed.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.23 no.1
• /
• pp.10-19
• /
• 1986

This is the last part of the four-part describing the development of a packet-switched computer communication network named the KORNET. In this paper we describe the design and implementation of the packet assembler/dissassembler (PAD) protocol for the asynchronous channel service, and of the network management softwares. The line processing module-B(LPMB) system supporting the asynchronous line includes a PAD protocol, a packet mode DTE/DCE protocol converting to the X.25 protocol, and the asynchronous receiver/transmitter(ART) software. The network management software is operated in master central processing module(MCPM) which includes virtual circuit management (VCM) managing the user channel, the routing management and the high level protocol for communication between the network management center (NMC) and the network node processor(NNP). In this paper, the design, implementation and operation of the softwares for the above service functions will be described in detail.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.16 no.5
• /
• pp.1-11
• /
• 1979

Since the second half of 1960's one of the information industry's most vital, yet least-well-understood areas has evolved-Data communications/Computer communications. To successfully realize this field we have to identity and reveal a variety of fundermental characteristics of communications channels and see their high reliability as prerequisites. This paper has accumulated related data from 1973 on, systematically analyzed them and provided some basic back ground and suggestions. Error rate which is the final and external characteristics of communication lines according to channal types, communication types and speed, block length and geographical difference between test points was extensively examined as well as their frequency response and d-c characteristics. The perspective of 9600BPS high speed data communications was also discussed.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.34S no.7
• /
• pp.19-27
• /
• 1997

This paper presents the performance analysis of MC-CDMA system in reverse links acquired through the computer simulation. For channel estimation which is essential component of mobile communications, a modified alpha algorithm is proposed to estimate the channel sate for MC-CDMA system. In order to update the channel estimator of each subchannel, the modified algorithm uses the final hard-decision value in the receiver.

• Information and Communications Magazine
• /
• v.20 no.12
• /
• pp.14-31
• /
• 2003

텔레매틱스(Telematics)는 자동차와 컴퓨터.이동통신 등 다수의 이종기술의 결합을 의미한다. 텔레매틱스는 또한 유, 무선통신망 등을 통해서 운전자가 정보를 교환하여 운전자 및 차량의 안전 및 편의성을 향상시킬 수 있는 장치 및 서비스를 통칭한다. 휴대용 개인 단말기와 달리 차량에 장착되는 텔레매틱스 단말기는 차량 정보 네트워크에 연결되어 주행 안전이 가장 우선 되어야 하고 부가적인 운전자 정보 서비스가 이루어 져야 한다. 이제까지 제안 또는 적용 되고 있는 기술을 중심으로 텔레매틱스 기술 동향을 요약하였다. 주행 중에 제공되는 서비스로서 텔레매틱스는 안전 관련 제도적 보완이 필요하고 특히 국가 차원의 공공 인프라 지원 정책이 뒷받침되어야만 하는 국가 정책 차원의 지원이 반드시 이루어 져야 한다.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.35C no.5
• /
• pp.59-68
• /
• 1998

This paper proposes a neural network algorithm for a channel assignment in cellular mobile communications. The proposed algorithm is developed base on hopfield neural network in order to minimize the number of channel without a confliction between cells. To compare the performance of the proposed algorithm, we used seven benchmark problems selected from kunz's and funabiki's papers. Experimental results show that the convergence times are reduced form 27% to 66% compared with Kunz's and funabiki's algorithm and vonvergence rates are improved to 100%.