• 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 electromagnetic engineering and science
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• v.12 no.1
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• pp.20-25
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• 2012

In this paper, the EM wave absorber for ETC system was designed and fabricated. We fabricated several samples in different composition ratios of flaked sendust and CPE(Chlorinated Polyethylene). Absorption abilities were simulated in accordance with different thicknesses of the prepared absorbers and changed complex relative permittivity and permeability according to composition ratio. The optimized mixing ratio of flaked sendust and CPE was found as 60 : 40 wt.% by experiments and simulation. Then the EM wave absorber was fabricated and tested using the simulated data. As a result, the developed EM wave absorber has the thickness of 2.75 mm and absorption ability was 22.5 dB in the case of normal incidence at 5.8 GHz. Therefore, it was confirmed that the newly developed absorber can be used for ETC system.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.1272-1277
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• 2004

GPS type portable-alarm-system is composed of satellite receiving equipment, signal transmission equipment, etc. Time errors occur because of the processing methods of the satellite receiving equipment and signal generator, the positional error of GPS itself, etc. With the recent rise of train speed, it becomes very important to secure the stability of portable-alarm-system from time errors, The present study estimated errors caused by the structure of portable-alarm-system, GPS errors. etc., and verified them. In addition, it examined the effects of such errors on portable-alarm-system according to train speed.

• Proceedings of the KIEE Conference
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• 1989.07a
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• pp.251-253
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• 1989

The Battery Storage System (BSS) has been used in foreign country for Load Levelling, Flicker Compensation, Load Frequency Control, etc. because it has easy application characteristics compared to the other storage system such as the Pumped Hydro System, Compressed Air System, etc.. In this paper, the application field and available capacity of BSS is outlined in Korea.

• Proceedings of the CALSEC Conference
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• 2001.08a
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• pp.165-176
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• 2001

* Extension of EC(Electronic Commerce) * Standard of Message -EDI : UN/EDIFACT, ANSI X12, etc -XML : ebXML, CML, MathML, WIDL, etc * Various of Information -Business Transaction Data -Private Data : ID, Password, Personal Information -Charge Data : Accounts, Card, etc * Message Level Security(omitted)

• Transactions of the Korean Society of Automotive Engineers
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• v.18 no.2
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• pp.122-128
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• 2010

To meet the NOx limit without a penalty of fuel consumption, urea-SCR system is currently regarded as promising NOx reduction technology for diesel engines. SCR system has to achieve maximal NOx conversion in combination with minimal $NH_3$ slip. In this study, the performance characteristics of urea-SCR system with open loop control were assessed in the European Transient Cycle(ETC) for heavy duty diesel engine. The SCR inlet temperaure varied in the range of 200 to $340^{\circ}C$ in the ETC cycle. Open loop control calculated the urea flow rate based on the NOx and NSR map which gave for each combination of SCR inlet temperature and space velocity the normalized $NH_3$ to NOx stoichiometric ratio which resulted in a steady-state $NH_3$ slip of 20ppm. During the ETC cycle, the open loop control with the optimized NSR offset achieved NOx reduction of 80% while keeping the average $NH_3$ slip below 10ppm and maximum 20ppm. It was also found that NOx sensor was cross-sensitive to $NH_3$ and a control strategy for cross-sensitivity compensation was required in order to use a NOx sensor as feedback device.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.345-357
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• 1990

Accumulated data on medical care utilization among the insured in Korea Medical Insurance Corporation can explain the health status of the population. The purpose of this study was to analyze a change of the disease-mix and utilization pattern by controlling the size of the population enrollment. Major findings of the study are as follows : 1. The changes of inpatient disease-mix a. Utilization rate was 139.2% in 1988 against 1980. b. Disease groups higher than the average utilization rate included neoplasms, endocrine, nutritional and metabolic diseases and immunity disorders, mental disorders etc. Meanwhile, disease groups seen less often were infections and parasistic diseases, diseases of blood and bloodforming, diseases of the digestive system etc. c. Utilization rate was up 106.3% in 1988 compared to 1985, and diseases above that average level were ill-defined intestinal infections, chronic liver disease and cirrhosis, diabetes mellitus, essential hypertension, etc. d. The disease-mix by institution in 1988 compared to 1985 shows that chronic disorders rank high in general hospitals whereas opthalmologic, obstetric, and orthopedic diseases rank high in private clinics. 2. The changes of outpatient disease-mix a. Utilization rate was up 175.2% in 1988 compared to 1980. b. Disease groups higher than the average utilization rate included neoplasms, endocrine, nutritional and metabolic diseases and immunity disorders, mental disorders etc. And disease groups seen less often were infections and parasistic diseases, diseases of the respiratory system, diseases of the genitourinary system. etc. c. Utilization rate was up 104.0% in 1988 compared to 1985, and diseases above that average level were gastric ulcer, diseases of hard tissues of teeth, etc. And diseases seen below that average level were acute nasopharyngitis(common cold). acute upper respiratory infections of multiple or unspecified sites, etc. It was concluded that medical care utilization level was increased, and that, from 1980 to 1988, disease-mix shifted to the chronic disorders. Chronic disorders accounted for more medical care utilization in general hospitals.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.7
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• pp.1147-1155
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• 2000

The installation of wireless communication system for various services of ITS at 5.8 GHz generates mutual interference. The representative example, the sharing of frequency between DSRC system and ETC system is a cause of communication error or disturbance both sides or one side owing to mutual interference. As a solution, a Shield Plate, Antenna Directionality, Power Control is proposed, but these are not perfect solution, because a RSU doesn't have the information of position of interferer. This paper applies an adaptive array antenna which makes a gain for desired users, makes a null for interferer, to up-link, down-link of DSRC and ETC system. The analysis of BER performance shows the effect of reduced interference about 20 dB.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.6B
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• pp.527-533
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• 2006

In this paper, we analyze the performance of MAC (Media Access Control) layer in DSRC (Dedicated Short Range Communication). It will be widely applied for ITS (Intelligent Transportation System) services; for example ETC (Electric Toll Control), BIS (Bus Information System) etc., needed to small packet size. But If ITS service is evolving to advance ITS, ADIS (Advanced Driver Information Systems) and AVHS (Advanced Vehicle Highway System) etc, be needed larger packet size. In the future, it may offer more various services such as traffic information, collection, and multimedia information. There are two kind of physical media, IR(Infrared) and RF(Radio frequency). And each system has their own protocol that is adaptive in special characteristics of physical medium for using efficiently limited radio resources. In this paper, we analyze the special characteristics of each system. And we study practical use of some related services expected to be used in the near future, by analyzing the transmission efficiency in each DSRC system.

• Journal of Navigation and Port Research
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• v.35 no.9
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• pp.749-753
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• 2011

A leisure ship has a stand-alone type power system, and a generator is in use on this condition. But the generator cannot be operated in condition of leisure activity, ocean measurement and etc, because of environment and noise. Recently, renewable energy system is connected with power system of the leisure-ship for saving energy. The renewable energy system can not supply the stable power to leisure-ship because power generation changes according to weather condition. And most of the leisure ship is operated without methodical power management system. This study's purpose is to develop SPMS(Smart Power Management System) algorithm using the renewable energy (photovoltaic, wind power and etc.). The proposed algorithm is able to supply stable the power according to operation mode. Furthermore, the SPMS manages electric load (sailing and communication equipment, TV, fan, etc.) and reduces operating times of the generator. In this paper, the proposed algorithm is realized and executed by using LabVIEW. As a result, the hour for operating the generator is minimized.