• Journal of information and communication convergence engineering
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• 제4권2호
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• pp.53-57
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• 2006

The objective of this paper is to propose a system by means of which the utilization of radio frequency. spectrum may be improved from the state of extreme inefficiency at the present time in Kazakhstan to a state of efficiency and equilibrium in the future.

• Journal of the Korean Society for Railway
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• 제10권5호
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• pp.589-595
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• 2007

Korea Railroad Research Institute has developed the driverless rubber-tired K-AGT (Korean-Automated Guideway Transit) system from 1999 to 2005 and has done its performance and reliability tests on the test line at Gyeongsan-city. Radio Frequency Communication-Based Train Control system of K-AGT, which employed Advanced Automated Train Control scheme, detects train position using the radio propagation delay between wayside and vehicle radio equipment. In this paper, we investigate whether the transmission power of radio system can be reduced to the permitted level announced by the Ministry of Information and Communication for license-free ISM(Industrial Scientific Medical) frequency bands. We first determine radio propagation model, using the measured data at test line, and perform simulation for radio coverage prediction. From the simulation results, we identify that the radio system operated with reduced power can provide good link quality in total test line.

• The Journal of the Korea institute of electronic communication sciences
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• 제11권5호
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• pp.441-450
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• 2016

The International Telecommunications Union(: ITU) Radio Regulations(: RR) and in which is defined as the frequency of electromagnetic waves below 3000GHz spread in space without artificial guidance, our country also follows the international definition. As radio waves are electromagnetic waves spreading in space without artificial induction means having a frequency within the range set by the ITU. Frequency distribution for dual-work is to inde 300GHz, among the divided frequency is our daily or less than 90% of the frequency band is in contact saenghwalyong 3GHz. Propagation, but can occur indefinitely without depleting that anyone can create only gatchumyeon transmission equipment, if the radio frequency to use at the same time and space, the soul is the interference occurs is not available radio resources. Due to the physical finiteness used in our country for the first time on such a propagation laws enacted in 1961 and to the state radio resource management, and rules to be used for propagation only if granted the rights.

• Proceedings of the KSR Conference
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.594-601
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• 2000

Communication Based Train Control System supports the easy maintenance ＆ management and also have the capability to send more informations than the existing one but is less expensive. Tolerance against fault/failure and reliable data transmission are very important issues with this system since it has the responsibility of man's safety. In this paper, we suggested the schemes to support the reliable transmission quality and fault safety. Also we verified through simulation.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 한국통신학회 2004년도 추계종합학술대회 논문 초록집
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• pp.339-339
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• 2004

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.116-122
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• 2004

The HF band communication of roast radio station had operated with principal axis of maritime communication until early in the 1990. But, that is changed with development of data communication and satellite technique, which have operated a few by rapidly decrement of user with accomplishment of the GMDSS. Recently, the radio system of 11u band is expanded to globe maritime communication, which is support to maritime safety information and data traffic service by low charge with the SSB high speed modem. This study have proposed the digitalize method for maritime communication system using HF band in domestic.

• Proceedings of the Korea Information Processing Society Conference
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• 한국정보처리학회 2009년도 춘계학술발표대회
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• pp.1277-1280
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• 2009

본 논문은 ITU-T 권고안 J-38 부록 B에 명시된 전송방식의 분석 및 시뮬레이션을 토대로 성능을 분석 하였으며 FPGA 구현시 야기되는 문제점을 나타내고, 해결방안을 제시하였다. 구현상의 문제점으로는 크게 두 가지로 분류되는데, 첫째로 다양한 부호화 방식과 변조방식 그리고 심볼 단위 및 비트 단위의 처리로 인해 많은 클럭수를 요구하는데 본 논문에서는 읽기/쓰기 메모리를 이용하여 필요한 클럭수를 줄였다. 둘째로는 펑쳐링 부호화된 TCM 복호기에 펑처링 패턴에 정확한 동기를 얻지 못하면 프레임 동기 심볼인 UW(Unique sync-Word)를 획득하지 못하여 모든 데이터가 에러 처리되기 때문에 본 논문에서는 펑처링 패턴과 UW 심볼의 동기를 맞추는 알고리즘을 제시하였다. 이러한 알고리즘 분석 및 구현상의 문제점 해결을 토대로 본 논문에서는 ITU-T J38 annex B의 하향 스트림 채널 부호화 시스템을 VHDL 언어를 사용하여 FPGA 칩에 직접 구현하였다.

• Journal of electromagnetic engineering and science
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• 제15권3호
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• pp.158-166
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• 2015

The early detection of breast cancer is very important. The final goal of this study is to develop an inexpensive portable device for simply detecting the existence of breast cancer using microwaves. In this study, we proposed a detection algorithm and the system configuration of such a device. The feasibility of the proposed method was investigated by numerical simulation and actual measurement. A prototype sensing module was fabricated, and the measurement results for tumor phantoms were presented. The measurement results showed that the prototype sensing module worked well, and the simulation results revealed that the detection rate of the device could be about 60% for a 4 mm tumor and almost 100% for a 6 mm tumor. The proposed device can be used for the self-diagnosis of breast cancer. Further study is required to reduce the size of the sensing module.

• Journal of IKEEE
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• 제13권3호
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• pp.87-94
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• 2009

TETRA(TErrestrial Trunked RAdio) is the wireless communication system generally adopted to public network and backbone network, as the technology of Trunked Radio System specified by ETSI(European Telecommunications Standards Institute) and currently adopted to the Electric Power IT Backbone Network in Korea. IEC 61850 is the protocol proposed for SAS(Substation Automation System) of SCADA(Supervisory Control And Data Acquisition) system. In this paper, IEC 61850 Server and Client simulator are used based on Linux operating system. The multi-functional gateway, which transforms the communication based on TCP/IP between IEC 61850 Server Simulator and Client Simulator to the one based on TETRA Packet Data Service, is developed such that IEC 61850 SCADA system is constructed based on TETRA.

• International Journal of Internet, Broadcasting and Communication
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• 제8권3호
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• pp.69-77
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• 2016

Maximum utilization of unused license spectrum is one of key factor in cognitive radio network which can handle the large number of systems and devices connected on smart grid AMI network. The central intelligence control system has responsibility to accept new technologies and users for automation. To ensure a reliable communication in smart grid system through cognitive network, a minimum mean square error (MSE) signal using unused licensed spectrum (or frequency) is necessary to be detected with small decision error. In this paper, we introduce a user control wireless smart grid system with minimum MSE using LMS algorithm.