• International Journal of Highway Engineering
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• v.11 no.2
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• pp.37-44
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• 2009

Currently the reasonability of threshold values for rutting and cracking does not clearly defined at the Pavement Rehabilitation Decision Tree on national highway PMS(Pavement Management System). The goal of this study is to provide the reasonable threshold values for the national highway asphalt concrete pavement rehabilitation. To achieve this goal, test section that represents typical asphalt concrete pavement of national highway was selected and pavement export were participated. Pavement condition survey has been conducted and pavement performance data at the selected roadway section were analyzed. From this study, reasonable threshold values of Pavement Rehabilitation Decision Tree were suggested based on the pavement expert's engineering judgement. In terms of crack repairs, the application of overlay after cutting is required to deteriorated area where existing crack ratio is over 35% and just overlay is required to where crack ratio is over 20%. On rutting, rut depth over 13mm is required to overlay after cutting and rut depth over 10mm is just needed to overlay.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.6
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• pp.453-460
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• 2014

We analyze fault detection algorithm of ephemeris included in navigation message, which is one of the GNSS risk factors. This algorithm uses carrier-phase measurement and baseline vector of two reference stations and is alternative method for uncertainty condition of previous ephemeris. Even though same ephemeris fault is occurred, the geometry condition, between baseline vector of reference stations and satellites, effects on performance of algorithm. Also, we introduce the suitable geometry of reference stations, threshold and performance index (MDE : Minimum Detectable Error) in jeju international airport.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.06a
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• pp.298-303
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• 2011

최근 한반도의 잇따른 북한의 Jamming(교란신호)으로 인해 무선통신 기반 산업에 피해사례가 늘고 있다. 이에 국토해양부(위성항법중앙사무소)에서 운영중인 위성항법보정시스템(이하 "DGPS") 데이터 분석하였다. 그 결과 2010년도 발생한 재밍과 달리 2011년도에는 DGPS 기준국/감시국에서는 감지가 되지 않은 것으로 분석 되었으나, 피해 현황을 조사하여 이를 토대로 범국가적 대책방안(항행 백업시스템 개발, 유관기관과의 정보공유를 통한 감지 통합시스템 구축) 및 DGPS 운영 효율성 확보방안(감시국 신설, 실시간 감시프로그램 강화 등)에 대하여 제안하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.952-958
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• 1994

In this paper a method calculates the time offset between a binary sequence and its shifted sequence based on the number theoretic approach is presented. Using this method the time offset between a binary sequence and its shifted sequence can be calculated. It has been recongnized that the defining the reference (zero-offset) sequence is important in synchronous code division multiple access(CDMA) system since the same spreading sequence are used by the all base station. The time offset of the sequence with respect to the zero offset sequence are used to distinguish signal received at a mobile station from different base stations. This paper also discusses a method that defines the reference sequence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.59-65
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• 2012

The study conducted the measurement of RTK-GPS with changing the number of observation as the method to differ reference stations of RTK-GPS. Also it aimed to suggest an effective application plan for cadastral surveying based on the accuracy analysis accordingly. According to the result of selecting the study region, observing with different reference stations, and comparing with previous TS performance, the 1st reference station was calculated as ${\pm}0.024m$ for x-coordinate's RMSE and ${\pm}0.029m$ for y-coordinate's RMSE, and the 2nd reference station was calculated as ${\pm}0.040m$ for x-coordinate's RMSE and ${\pm}0.029m$ for y-coordinate's RMSE. All these results (the 1st and the 2nd reference stations) are allowed as acceptable performance within the margin of error according to the existing cadastral regulations, and there was no significant difference between two performances. Therefore, unless there was no problem in receiving GPS satellite data, it would be possible to secure stable performance enough with 1 observation. Depending on surveying environment that has possible problems in receiving data, however, 2 or more observations would be necessary to secure stable performance.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.19 no.5
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• pp.971-980
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• 1994

The need increased capacity in the cellular system has resulted in the adoption of digital technology with CDMA as the channel access method. It has been recognized that the distinction of the base station is important for its performance in CDMA, since the same spreading sequences are used by the all base stations. Time offset of the pseudo-random noise binary code are used to distinguish signals received at a mobile station from different base station. But the start of the zero offset PN sequence is chosen arbitrary without the background of the systematic and mathematical elaboration. This paper proposes a mothed that define the start of the zero offset PN sequence mathematically. This paper also discusses a method that can easily calculate the time offset of the received spreading sequence with respect to the zero offset PN sequence.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.119-121
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• 2020

해양사고는 많은 인명과 재산의 피해를 초래하고, 특히 유조선과 같은 위험물운반선의 사고는 대형오염사고를 수반하게 되어 연안국에 막대한 해양환경 피해를 주게 됩니다. 이러한 외국적 기준 미달선에 의한 해양사고 예방을 위한 항만국 PSC 점검 시 해당선박에 대한 PSC 결함항목 Checklist와 결함항목과 관련된 국제협약 근거를 즉시 제공함으로써 PSC 점검율 제고를 통한 우리 항만에서의 해양사고 예방 및 해양환경을 보호하기 위한 PSC 점검지원 서비스에 대한 연구를 하였습니다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.429-431
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• 2022

해양사고는 많은 인명과 재산의 피해를 초래하고, 특히 유조선과 같은 위험물운반선의 사고는 대형오염사고를 수반하게 되어 연안국에 막대한 해양환경 피해를 주게 된다. 이러한 외국적 기준 미달선에 의한 해양사고 예방을 위한 항만국 PSC 점검 시 해당선박에 대한 PSC 결함항목 Checklist와 결함항목과 관련된 국제협약 근거를 즉시 제공함으로써 PSC 점검율 제고를 통한 우리 항만에서의 해양사고 예방 및 해양환경을 보호하기 위한 PSC 점검지원 서비스에 대한 연구를 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2023.05a
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• pp.93-95
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• 2023

해양사고는 많은 인명과 재산의 피해를 초래하고, 특히 유조선과 같은 위험물운반선의 사고는 대형오염사고를 수반하게 되어 연안국에 막대한 해양환경 피해를 주게 된다. 이러한 외국적 기준 미달선에 의한 해양사고 예방을 위한 항만국 PSC 점검 시 해당선박에 대한 PSC 결함항목 Checklist와 결함항목과 관련된 국제협약 근거를 즉시 제공함으로써 PSC 점검율 제고를 통한 우리 항만에서의 해양사고 예방 및 해양환경을 보호하기 위한 PSC 점검지원 서비스에 대한 연구를 하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2021.11a
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• pp.207-209
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• 2021

해양사고는 많은 인명과 재산의 피해를 초래하고, 특히 유조선과 같은 위험물운반선의 사고는 대형오염사고를 수반하게 되어 연안국에 막대한 해양환경 피해를 주게 된다. 이러한 외국적 기준 미달선에 의한 해양사고 예방을 위한 항만국 PSC 점검 시 해당선박에 대한 PSC 결함항목 Checklist와 결함항목과 관련된 국제협약 근거를 즉시 제공함으로써 PSC 점검율 제고를 통한 우리 항만에서의 해양사고 예방 및 해양환경을 보호하기 위한 PSC 점검지원 서비스에 대한 연구를 하였다.