• Journal of the Korea Institute of Information Security & Cryptology
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• v.31 no.5
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• pp.959-972
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• 2021

Decentralized Identity is based on the concept of self-sovereign identity, in which holders manage and provide their own credentials. However, a procedure is required to obtain credentials from issuers, and there is a risk of mess personal information leaking due to negligence of the issuers. In this paper, we propose a peer decentralized identity system based on Peer DID technology that allows only participants to verify their identity in 1:1 or 1:N small groups by matching the holder with the issuer. It is directly connected to a mobile device using short-range wireless communications such as bluetooth, and the holders create and provide their own credentials in person to the other party, thus fully realizing the self-sovereignty identity. The proposed system can simplify the identification process, improve security and privacy, and reduce costs. Furthermore, an extended architecture is possible to connect the proposed system and the distributed ledger to identify users in other domains. In the future, based on various technologies, it is also necessary to expand research on identity systems that can be utilized for human-to-thing and things-to-things authentication.

• Journal of the Korea Society of Computer and Information
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• v.26 no.9
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• pp.133-141
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• 2021

The development and demand for the system that provides users with traffic information and efficient road use have continued. also, this system provides the basic technology of the Intelligent Transport System (ITS). The most used traffic information collection tools are Vehicle detectors (VDS) and short-range wireless communication (DSRC) on express way. In order to generate reliable traffic information, it is necessary to efficiently manage and utilize the collected data as well as high-quality traffic data collection and processing technology. In this study, traffic information collection·processing·provision systems were investigated, and analyze the current status and problems of traffic information collected through VDS. Based on this, we would like to present an improved collection algorithm that utilizes the Kalman filter for vehicle information measurement of VDS data. By using the algorithm of this study, it is possible to minimize the time delay of the estimated value as well as the noise removal that inevitably occurs during measurement.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.1B
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• pp.175-182
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• 2000

(A hybrid-type wireless infrared data communication module was fabricated by using the light emitting andabsorption diodes with the one-chip of integrated digital circuits. The light emitting diode with the peak spectrum of 850 nm was made from compound semiconductor material of AIGaAs and shows high speed signal transmission with the delay time of 60 nsec for the light direction angle of 30". The Si PIN photodiode showsthe good absorption rate for the range of wavelength of 450-1050 nm and convex-type epoxy lens was utilized for the spectrum filtering on the visible-range spectrum below 750 nm, The data transmission speed is 115.2 kbps and the fabricated module satisfies on the IrDA 1.0 SIR standard requirements.)ments.)

• 한국정보통신설비학회:학술대회논문집
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• 2002.08a
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• pp.220-230
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• 2002

고속으로 주행하는 차량으로부터 차량의 일시정지함이 없이 자동으로 통행요금을 징수하기 위한 ETC(Electronic Toll Collection, 통행요금자동징수)서비스는 전용의 무선통신방식, 전자지불수단, 암호화, 영상인식, 실시간제어등의 다양한 기술을 필요로 한다. KT ETC 시스템은 능동형 DSRC(Dedicated Short Range Communication, 단거리전용통신)를 이용한 상용의 ETC 시스템이다. 본 논문에서는 KT ETC 시스템의 개발과 관련하여 핵심 기술인 능동형 DSRC와 ETC 서비스를 위한 스마트카드 기술등을 소개하고, KT ETC 시스템에 고유한 ETC 서비스 처리절차를 소개한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3998-4004
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• 2010

This study investigated the agents for self-healing system that could be developed to prevent UST(underground storage tank) from leaking. The system involves short range wireless communication to locate a leakage. Four commercially available silicons are arbitrarily chosen to evaluate suitability as a self-healing agent through a series of laboratory experiments. finally the experiments are simulated using computational Fluid Dynamic Program.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.7 no.3
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• pp.263-271
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• 1996

The frequency band above 20GHz is the great radio resource which has not been used. But the attenuation by atmosphere is so large that the radio systems using this frequency band must have shorter hops. There are few studies of optimal hop length for these millimetric wave radio links in Korea. In this paper we analyzed the millimetric wave propagation characteristics in atmosphere and estimated rain attenuation which have a great effect on hop length. Furthermore, we present a rainfall rate(mm/h) of the cities including Seoul and Pusan using the data collected by several rainfall gauges. This paper presents a method of obtaining the optimum hop length for millimer wave radio links based on the rain rate date.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.8
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• pp.1030-1036
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• 2020

The DSRC method currently in use has a limitation in providing various ITS services by short-distance wireless communication. Therefore, the WAVE/DSRC hybrid wireless platform, which was developed by applying WAVE technology in-house, improved the data transmission speed and greatly expanded the transmission range. The summary H/W and S/W technologies are summarized in the text. In this paper, various services such as BSM, SPAT, MAP, and road video information related to ITS services have been implemented, and various tests are conducted based on scenarios considering the environment in the actual field by utilizing the previously developed WAVE/DSRC composite wireless platform. Through this emulation process in the real field, we were able to verify the excellence of the WAVE/DSRC composite wireless platform once again and predict the usefulness and potential of development services in real field operations.

• Proceedings of the Korean Society of Computer Information Conference
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• 2018.07a
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• pp.151-152
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• 2018

Dedicated Short-Range Communication은 단거리 무선 고속 패킷 통신 기능을 제공하며, 신뢰성, 안전한 데이터 전송 및 낮은 대기 시간으로 인해 Road Safety Application에서 널리 사용되고 있다. 본 논문에서는 SDN의 분산 컨트롤러를 이용하여 DSRC 통신을 제어하는 방식을 제안하였다. 제안한 기법을 실용화한다면 차량을 기반으로 한 실시간 교통 정보 수집이 보다 효과적으로 이루어질 것으로 기대된다.

• The Journal of the Korea institute of electronic communication sciences
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• v.11 no.8
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• pp.735-742
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• 2016

The Low-Rate WPAN is a short range wireless networking technology characterized by low-rate, low-power, low complexity and low-cost. The LR-WPAN controls wireless channel access among network devices based on the contention-based CSMA/CA algorithm. Therefore, frame collisions may take place at any time, leading to the severe degradation of network performance. This paper proposes a new algorithm that changes back-off periods adaptively in the CSMA/CA process depending on network conditions, resulting in the reduction of frame collisions. Throughout extensive simulations, it turns out that varying the back-off periods dynamically shows better performance than maintaining the fixed back-off periods.

• The Journal of the Acoustical Society of Korea
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• v.26 no.7
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• pp.366-374
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• 2007

In underwater wireless communication, needs for long distance communication using the high frequency are surpassing ones of short range communication by ultrasonic wave, and demands for transmitting and receiving various data such as voice or high resolution image data are increasing as well. In this work, we studied the effects on the real underwater communication depending on the difference of digital modulation methods. Simulation shows that only the performance of GMSK among many other PSK based modulation schemes(BPSK, QPSK, MSK, GMSK) is significant. Test condition simulates the oceanographic conditions along the 207-survey line, 15Km south of Busan and SNR is maintained 35dB or below. Simulated tests are composed of both transmitting image data($3{\times}10^5$ pixel, 4 bit per pixel) and voice communication($10^{-2}$BER, channel capacity of 1Kbps). Test results show that there are gain of about 7 seconds in transmission time in image transmission case, where channel capacity for BPSK, QPSK, and MSK and for GMSK were 65 Kbps and 45 Kbps, respectively and gain of about 8Km in distances in voice communication case.