• Journal of the Korean Society of Marine Environment & Safety
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• v.10 no.2 s.21
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• pp.61-67
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• 2004

The development motive and maintenance of navigation system were military strategy purpose since middle of 20th century. During cold war period between the United States and the Soviet since the Second World War, advanced navigation system that two countries are responded individually have done development competitively. These systems are exhibited on general except military purpose gradually and are taking charge of point role in economy transport activity such as transportation of logistics between the country. Navigation system can divide into ground system and satellite system. Representative system of ground system is Loran-C(Long Range Navigation), and representative system of satellite system is GPS(Global Position System). Loran-C system is a system that use much in all the world country sea and ground, but GPS and DGPS that present is a satellite navigation system are used much. According to development of satellite system, examine about actual conditions of Loran-C navigation system and practical use plan in this paper because there is controversy about role of Loran-C navigation device along with Loran-C's operation and user decrease, and discusses for Loran-C's development direction.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.1
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• pp.123-133
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• 2018

Cyber-Physical System (CPS) is a system in which a physical system and a cyber system are strongly integrated. In order to operate the target physical system stably, the CPS constantly monitors the physical system through the sensor and performs control using the actuator according to the current state. If a malicious attacker performs a forgery attack on the measured values of the sensors in order to conceal their attacks, the cyber system operated based on the collected data can not recognize the current operation status of the physical system. This causes the delay of the response of the automation system and the operator, and then more damage will occur. To protect the CPS from increasingly sophisticated and targeted attacks, countermeasures must be developed that can detect stealthy deception attacks. However, in the CPS environment composed of various heterogeneous devices, the process of analyzing and demonstrating the vulnerability to actual field devices requires a lot of time. Therefore, in this study, we propose a method of constructing the experiment environment of the PLCitM (PLC in the middle) which can verify the performance of the techniques to detect the CPS stealthy deception attack and present the experimental results.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1713-1720
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• 2009

An local area weather condition monitoring system to minimize many disasters from the sudden change of weather condition in local and mountain ales is proposed. Firstly, the comparison of present state of the related monitoring systems and the possibility of realization with some merits are investigated. Moreover, this paper present direction of local area weather condition monitoring system based on integration of wireless sensor network and CDMA network following some case study. The sensor node for wireless sensor network and an interface dongle are fabricated for the system. The stand-alone software in cellular phone is also developed. Through the efficient integration of both networks, the measured weather condition data from sensors can be transmitted to the server or mobile to monitor with high reliability. The proposed monitoring system will guide new type of project in wireless sensor network and support alarm service of the sudden change of weather condition to mobile user from central official regulations.

• Journal of Digital Convergence
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• v.15 no.7
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• pp.41-53
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• 2017

This study focuses on the current state of Smart Grid policy in Japan and its problems while the interest in Smart Grid has been increasing since the March 2011 earthquake in East Japan. As a result of the analysis, Japan introduced the fixed price buying system of new and renewable energy in response to the power supply and demand problem caused by the 2011 earthquake in East Japan, and established a decentralized green electricity trading market in which electricity generated from new and renewable energy is traded Smart Grid-related projects were implemented as a solution to solve energy crisis and environmental problems at the same time. As a result, we achieved visible results such as suppressing peak power, reducing CO2 emissions, and securing stable supply and demand of energy using renewable energy sources. On the other hand, the improvement of current Smart Grid policy operation in Japan and the introduction of stabilization system of power system, promotion of international standards of domestic technology related to smart grid, and support for strengthening security of smart grid.

• Journal of Navigation and Port Research
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• v.37 no.6
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• pp.581-586
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• 2013

The sea traffic volume in Southwest sea including Wando area have increased every year. However the improvement of the facilities for convenience and safety in port and sea was not enough to meet the increasing demand of traffic and passengers' need. This study dealt with the situations and status of passenger ship traffic system in Wando area. In addition to, questionnaire survey of passenger ship user in Wando area was carried out in order to research the improvement of marine traffic system. On the basis of the result, navigation risks in the area was analysed. The institutional system such as passenger ship fare, enhanced traffic system that can improve marine traffic environment in the area were suggested and examined. The urgent issue was the scattered fishing ground near fairway which makes narrow passage and can cause risky passeger ship's navigation. In the side of passeger ship's operation, the wage of cargo handling was relatively expensive that needed to be improved.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.1362-1366
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• 2006

우리나라에서는 하천법 제11조에 의거하여 10년마다 한 번씩 수자원장기종합계획을 수립하고 있으며, 필요에 따라 5년마다 이를 수정 보완하고 있다. 2001년 7월 수자원장기종합계획(Water Vision 2020)이 수립된 이후 잦은 봄 가뭄 등 이수측면에서의 사회, 경제, 환경의 변화와 최근 이상홍수 등으로 인한 대규모 홍수피해 발생에 따른 치수측면의 종합적인 대책의 제시가 요구되면서 2001년 수립된 계획에 대한 보완 필요성이 제기되었다. 또한 수자원계획의 신뢰성에 대한 시민단체 등의 문제제기와 지역 차원의 수자원계획 및 수자원환경에 대한 국민적 관심 증대로 인해 계획 수립 과정과 결과에 대한 국민적인 공감대 형성을 위한 체제의 구축이 금번 보완 계획의 수립을 통해 추진되고 있다. 금번 수자원장기종합계획 보완은 투명성 확보라는 큰 목표를 가지고 수행되고 있으며, 이를 통해 국가 수자원 관리의 청사진을 제시하고 물 수급 전망 및 용수수급 계획을 수립하는 과정에 있다. 기 개발된 한국형 통합수자원평가계획 모형인 K-WEAP 모형을 보완 계획 수립 과정에서 활용하고 있으며, K-WEAP 모형을 통해 물 수지 분석을 수행하여 수급 균형을 판단함으로써 일반 대중에게 물 수급 관련 상황에 대한 이해력을 높일 수 있다는 장점을 확보할 수 있다. 본 연구에서는 K-WEAP 모형을 이용하여 각 권역별로 2003년의 물 수급 현황을 분석하여 이를 하천의 관측유량과 비교해봄으로써 모형의 검증을 수행하였으며, 각 권역에서 시나리오별로 추정된 용수수요량을 이용하여 물 수지 분석을 수행함으로써 목표연도별 물 수급 분석결과를 제시하였다. 물 수급 분석 시 지하수 및 농업용 저수지 등 하천과 다목적댐 이외의 지역 공급원에 대해서도 고려하였으며, 이를 통해 수자원계획 수립 시 도움이 될 수 있는 기초적인 자료를 제공할 수 있었다. 인공순환에 의한 저감효과가 크지는 않을 것으로 예측된다. 조사 기간중 H호의 현존 식물플랑크톤량의 $60%{\sim}87%$가 수심 10m 이내에 분포하였고, 녹조강과 남조강이 우점하는 하절기에는 5m 이내에 주로 분포하였다. 취수탑 지점의 수심이 연중 $25{\sim}35m$를 유지하는 H호의 경우 간헐식 폭기장치를 가동하는 기간은 물론 그 외 기간에도 취수구의 심도를 표층 10m 이하로 유지 할 경우 전체 조류 유입량을 60% 이상 저감할 수 있을 것으로 조사되었다.심볼 및 색채 디자인 등의 작업이 수반되어야 하며, 이들을 고려한 인터넷용 GIS기본도를 신규 제작한다. 상습침수지구와 관련된 각종 GIS데이타와 각 기관이 보유하고 있는 공공정보 가운데 공간정보와 연계되어야 하는 자료를 인터넷 GIS를 이용하여 효율적으로 관리하기 위해서는 단계별 구축전략이 필요하다. 따라서 본 논문에서는 인터넷 GIS를 이용하여 상습침수구역관련 정보를 검색, 처리 및 분석할 수 있는 상습침수 구역 종합정보화 시스템을 구축토록 하였다.N, 항목에서 보 상류가 높게 나타났으나, 철거되지 않은 검전보나 안양대교보에 비해 그 차이가 크지 않은 것으로 나타났다.의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에 있어서 시장수익률을 평균적으로 초과할 수 있는 거래전략은 존재하므로 이러한 전략을 개발 및 활용할 수 있으며, 특히, 한국주

• Progress in Medical Physics
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• v.27 no.1
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• pp.46-53
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• 2016

Periodical calibrations of radiation detectors are important for accurate quality assurance of therapeutic linac. The measuring instruments such as ion-chamber, thermometer, barometer, and survey meter should be calibrated periodically. Period of calibration for these instruments is suggested 6 month to one year in Korea and two years in other countries nowadays. Therefore, the determination of reasonable period for calibration is needed. In this study, we plan to utilize the results of these survey; frequent in use, how to use and stability of instruments, to determine the optimized period of calibration for the instruments in the departments of radiation oncology in Korea based on the ILAC-G24. The SurveyMonkey web-based survey tool was used and the objects of survey were 18 department of radiation oncology in university hospitals, and 15 departments were answered. The 64 questionnaires which supposed to be answered in 50 minutes were classified as the information of candidates, the thermometer, the barometer, the surveymeter, and the ion-chamber. The thermometers and the barometers were not under periodical calibration for more than half of candidates. The periods of calibration of surveymeters were 6 month to 1 year. We expect that the calibration period can be determined based on these survey results.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.2
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• pp.78-82
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• 2005

Fishermen have higher risk of occupational injuries and disease due to frequent machine usage and direct contact to live biological materials. Moreover, growing elderly workers makes the susceptibility to occupational injuries and disease higher. This study was performed to investigate the occupational safety and health status among fishermen. The interview was carried out at Jumunjin and Geojin ports which were representative port at North East side of Korea. The structured questionnaire were used to interview the fishermen from AM 6:00 to PM 11:00 and total respondent were 97 workers. The results were followed; 7 fishermen of all respondents experienced occupational injuries during their work, 5 fishermen were needed to admission longer than 4 days. The injury types were contusion(4 persons), fracture(1 persons) and amputation(2 persons). The cause of injury might be the lack of caution and the unstability of working condition. These results suggested the ergonomical evaluation of working condition and proper management. But there was limited concern and studies on the policy on occupational safety and health on fishermen. So, further study was required to establish the sound policy of fishermen's occupational safety and health.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.10a
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• pp.255-258
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• 2011

Wi-Fi is a rapidly spreading communications network with Smart phone's publication, the technology has become Ubiquitous-based core network which is connected to personal computers, laptops, and tablet PC. Wi-Fi can send currently a variety of data standard due to developed wireless LAN communications network. One of Wi-Fi standard protocols, which is IEEE 802.11n, use 2.4GHz and 5GHz band. 2.4GHz band is used for 802.11b/g protocol because wavelength is long, diffraction and receiving distance is enough to connect other device. 5GHz band has more available channels to use than 2.4GHz band, so there is no frequency interference of other wireless device such as Bluetooth, RFID. Moreover, there is low interference between channels due to small users in each bandwidth level. In the thesis, we are going to analyze 802.11a/b/g protocol which has used since the beginning of Wi-Fi protocol and 802.11n protocol which is used lately. Furthermore, we look into development and direction for standardization of the next generation wireless LANs which are 802.11ac and 802.11ad. In addition, we will consider for the security, vulnerabilities and its countermeasure in Wireless LAN.

• Journal of the Korean Regional Science Association
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• v.38 no.2
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• pp.43-57
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• 2022

The Land Suitability Assessment is mandatory by National Land Planning and Utilization Act and the results are considered in the establishment of urban master plan and urban management plan. The study aims to examine whether the application of Land Suitability Assessment in developed urban areas is appropriate. A simulation analysis based on the Seoul's data of environmental ecological, physical, and spatial characteristics was conducted on urban green, the only applicable land for the assessment in Seoul. The results of the assessment shows that all pieces of lands in urban green is suitable for 'development'. This conflicts to the purpose of land use of urban green which needs to be conserved to protect the natural environment and landscape, animals and plants, environmental pollution, and urban sprawl. In the analysis applying optional indicators such as the distance from the area of Biotope Class 1 to prevent this conflict, the results shows little difference. This supports the necessity to review this regulation including an option to exclude developed urban areas such as Seoul in the assessment.