• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.120-123
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• 2009

The WiBro to start June 2006 is mobile internet service with 60km/h, 3Mbps. And current WiBro service is used in Seoul, the metropolitan area and the local major cities. This study suggests WiBro technology and analyzes wireless communication technology to vehicle-to-infrastructure communications for the unmanned vehicle control. We were driving vehicle with two laptop computer's WiBro unit for V2I communication environment. So each RAS(Radio Access Station) on center is tested coverage area, transmission rate, latency rate, lost rate and transmission rate to parking area environment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.3
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• pp.590-598
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• 2016

It comes into the spotlight as the new Blue Ocean in which the connected car industry in which the car and mobile communication technology is convergence. All sorts of infortainments services connecting with the portable electronic device(Smart phone, tablet PC, and MP3 player) and car are rapidly grown. The Connected car emphasizes the vehicle connectivity with the concept that the car has communication with the around on a real time basis and it provides the safety and expedience to the operator and using the thing of Internet (IoT) in the car and supports the application, presently, the entertainment service including the real-time Navigation, parking assistant function, not only the remote vehicle control and management service but also Email, multimedia streaming service, SNS and with the platform. Intelligent vehicle network is studied as the kind according to MANET(Mobile Ad Hoc Network) for the safety operation of the cars of the road and improving the efficiency of the driving.

• Electronics and Telecommunications Trends
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• v.26 no.6
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• pp.47-57
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• 2011

DARPA 무인차 대회 우승과 구글 자율주행 자동차로 유명한 세바스찬 스런 스탠포드대 교수는 18살이 되던 해에 가장 친한 친구를 교통사고로 잃었고, 그것을 계기로 계기로 무인차 개발에 나서게 되었다고 한다. 현재 대부분의 교통사고는 운전자의 과실로 발생하며, 기계의 보조나 자동제어가 있다면 대부분 예방할 수 있다. 또한 자동으로 차선을 유지하고 차간거리를 유지하게 해준다면 도로의 교통 수용량을 2배 내지 3배로 높일 수 있으며, 도로에서 보내는 시간과 연료를 절약할 수 있다. 현재 지능형 자동차 및 도로 인프라 기술은 이러한 운전자의 안전성, 편의성, 교통 효율성, 에너지 절약을 달성하기 위한 자동차와 인프라 간의 협력형 ITS(C-ITS: cooperative ITS) 방향으로 기술개발이 이루어지고 있으며, 본 고에서는 이와 관련된 차량 자동유도 요소 기술 및 동향에 대해서 살펴본다.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.19 no.2
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• pp.74-88
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• 2020

A Cooperative Intelligent Transportation System (CITS) provides useful information on upcoming hazards in order to prevent vehicle collisions. In addition, the availability of individual vehicle travel information obtained from the CITS infrastructure allows us to identify the level of road safety in real time and based on analysis of the indicators representing the crash potential. This study proposes a methodology to derive road safety content, and presents evaluation results for its applicability in practice, based on simulation experiments. Both jerk and Stopping Distance Index (SDI) were adopted as safety indicators and were further applied to derive road section safety information. Microscopic simulation results with VISSIM show that 5% and 20% samples of jerk and SDI are sufficient to represent road safety characteristics for all vehicles. It is expected that the outcome of this study will be fundamental to developing a novel and valuable system to monitor the level of road safety in real time.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.10a
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• pp.325-328
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• 2018

With the rapid development of autonomous driving technology, commercialization of freight cars and buses as well as passenger cars has come to the near future. As researches for commercialization of autonomous navigation are being actively carried out in various countries around the world, in accordance with the development of technology, this paper proposes a bus adopting a new concept of community driving technology based on C-V2X for more effective autonomous driving of buses do. In order to realize the cluster bus, we propose a more effective cluster bus using C-V2X, which is the core communication of the cluster driving, which is complementary to the existing V2X for inter-vehicle communication and vehicle-to-infrastructure communication.

• Journal of the Institute of Convergence Signal Processing
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• v.8 no.4
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• pp.266-271
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• 2007

In mobile channel environments, the effect of the multi-path fading reduces the performance of the mobile communication severely. Previous studies on the effect of the multi-path fading show that, only the channel between fixed base stations and mobile terminals are considered. However, the future mobile communication service such as telematics may use the communication between moving mobile terminals, so called mobile ad-hoc communication, the studies on the channel is required for such situations. In this paper we have measured the mobile channel and analyzed the fading characteristics when using the linear array antennas. In the data measurements, we sent the QPSK modulated signal with carrier frequency of 2GHz band and received the signal using the array antennas equipped on moving vehicles. We have analyzed the fading characteristics and the effects of the fading reduction using the CDF of fading depth using data collected from two moving vehicles. The simulation results show that the beamforming technique adds 6 or 7dB to the fading margin than that of the selection diversity depending on channel environments.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.7 no.1
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• pp.92-100
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• 2008

The existing transportation systems is emerged as a major obstacle to solve the problems such as a traffic jam and the increasing cost for a distribution and a traffic safety. In hun, ITS targeting intellectual vehicles and transportation infrastructure like road and signals is getting more important and the standards of ITS wireless communication is also getting attention. New traffic control strategies are being developed to utilize real-time traffic information collected by detection method using ITS wireless technology. Especially, DSRC system is being expanded wit ETCS and the use of OBU is spreading. These infrastructures will have much influence on ITS industry and a profound study on the method of utilizing a present infrastructure is going on in various fields. The optimum traffic signal control system using quality real-time information through these infrastructure is under development and so is WISDOM. Accordingly, this paper proposes communication protocol utilizing DSRC to collect real-time traffic information in WISDOM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.42 no.1
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• pp.67-74
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• 2022

In recent, the number of real-time traffic information sources and providers has increased as increasing smartphone users and intelligent transportation system facilities installed at roadways including vehicle detection system (VDS), dedicated short-ranged communications (DSRC), and global positioning system (GPS) probe vehicle. The accuracy of such traffic information would vary with these heterogeneous information sources or spatiotemporal traffic conditions. Therefore, the purpose of this study is to propose an empirical strategy of heterogeneous information fusion to improve the accuracy of real-time traffic information. To carry out this purpose, travel speed data collection based on the floating car technique was conducted on 227 freeway links (or 892.2 km long) and 2,074 national highway links (or 937.0 km long). The average travel speed for 5 probe vehicles on a specific time period and a link was used as a ground truth measure to evaluate the accuracy of real-time heterogeneous traffic information for that time period and that link. From the statistical tests, it was found that the proposed fusion strategy improves the accuracy of real-time traffic information.