• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.19-24
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• 2010

This paper analyzes potential interference effect of DTV service on Radio Microphone in adjacent channel. For analysis, we assume that DTV operates on CH 51(692 MHz ~ 698 MHz) and radio microphone operates on CH 52 (698 MHz ~ 704 MHz) according to the Korea Communications Commission policy. Minimum Coupling Loss(MCL) method is used to determine the required protection distance and Monte Carlo method is used to determine guard band to meet interference probability of 0 % below. In conclusions, protection distance of 1.71 km and guard band of 2.4 MHz are required for indoor and protection distance of 18.86 km and guard band of 5.7 MHz are required for outdoor.

• Journal of Satellite, Information and Communications
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• v.6 no.1
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• pp.103-108
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• 2011

This paper is related radio interference from inductive system to radio device in home and industrial environment according to increasing the usage of inductive system. In order to analyze interference from magnetic field strength of inductive system, interference model was suggested and explain the method to calculate separation distance by using conversion that from magnetic field strength to magnetic dipole moment based on suggested interference model. Also, scenario that interference occur between inductive system and radio device was shown and the separation distance between inductive system and radio device was calculate with that scenario. The suggested method in this paper will be used to secure the compatibility between inductive system and radio device.

• Journal of Korean Society of Transportation
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• v.33 no.4
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• pp.337-347
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• 2015

Since the application of roundabouts by 2010 have been started, more than 350 roundabouts were installed in Korea. Recently the types of constructed roundabouts become various, and the intersection conditions for installing roundabouts were also various. However, there were some difficulties to install roundabouts around school zone due to safety problems. In this study, appropriate distance from adjacent signal crosswalks to roundabouts were estimated for securing pedestrian safety and operation efficiency around school zone. With the analyses, the minimum distance standard was suggested to obtain operational effectiveness of roundabout according to traffic volume, traffic flow, pedestrian green time and secures pedestrian safety and convenience. In this paper, average delay of roundabout as various length of distances between an adjacent crosswalk and a roundabout as different pedestrian signal times, traffic volumes, traffic flow rates were analyzed. Through this study, it was found that about four times of delay in a roundabout was generated if there was adjacent signal crosswalk. However if there is enough distance between an adjacent crosswalk and a roundabout, the value of increasing delay on roundabouts with adjacent a signalized crosswalk can be considerably reduced. Critical value of the distance between a roundabout and a signal crosswalk in case of roundabouts within 200-500 vehicle/hour/lane entry traffic flow, 20-40% of left turn traffic, and over 15 seconds pedestrian green time was about 50 meters. In conclusion, if there is minimum 40 meter distance from roundabouts, adjacent signal crosswalks can be installed and operated for students' safety around school zone.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.135-135
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• 2019

수제는 만곡부의 유로 조정이나 하상보호와 같은 하천공학적인 목적을 가진 수공구조물이다. 본 연구에서는 개수로 만곡부에 수제 설치 시 외측벽과 수제 사이의 거리에 따라 하상변동이 어떤 차이가 있는지를 파악하기 위해 이동상 수리실험을 했다. 본 연구에서는 폭 1.45 m, 길이 24 m인 $90^{\circ}$ 만곡수로에 $4.2{\times}8.4cm$의 직사각형 단면 수제를 외측으로부터 이격하여 2열로 설치하였다. 하상재료는 $d_{50}$이 3.3 mm인 잔자갈을 사용했고 하상경사는 1/300로 하였다. 실험은 평균 유량 163 l/s를 3시간 동안 공급했고, 종료 후 만곡부의 주요횡단면별 하상고를 측정했다. 여기서 실험별 이격거리는 8.4 cm, 14 cm, 19.6 cm로 하였다. 실험 결과 외측벽과 수제 사이의 거리가 멀어질수록 만곡부의 최대세굴심은 커지고 그 발생 위치는 하류로 이동하는 경향을 보였다. 만곡부 최대세굴이 발생한 횡단면 형상은 만곡 내측에서 외측방향으로 무차원 위치 $y_1$(=내측에서의거리/폭)가 0.27보다 작으면 퇴적에 의해 하상이 상승하고, 0.35보다 클 때는 세굴에 따른 하상저하가 나타났다. 만곡 외측벽 부근 하상은 이격거리가 짧을수록 수제 설치에 의한 하상고 변화가 작았다.

• Proceedings of the KIEE Conference
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• 2004.05b
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• pp.203-206
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• 2004

IEC에 의하면 낙뢰의 보호효율은 1등급(최대98%), 2등급(최대95%), 3등급(최대90%), 4등급(최대80%)으로 나타내고 있으며, 광역피뢰침은 다수설치해야 하는 돌침형 피뢰침의 수량을 기술적으로 최소화 하여 건축물의 안전성과 경제성 등을 향상시키는 역할을 담당하고 있다. 그러나 이런 보호 능력은 설계 및 시공시 세심한 배려가 필요하다. 프랑스에서는 피격거리 60M를 한계로 하며 미국에서는 안전성을 좀더 신경 써 괴격거리 45M를 한계로 가능한 보호효율을 높이고 있는 실정이다. 광역피뢰침의 선정시 보호범위의 최대치 적용은 지양하고 보호 효율을 높여 적용함이 바람직하다. 또한 초고층 빌딩 및 APT단지의 경우 가급적 보호등급을 1등급으로 적용하는 세심한 배려가 필요하다. 시공시 광역피뢰침은 수평면 최고 돌출물(예:옥탈 및 안테나 등)의 설치 높이의 차는 2M이상이 필요하며 이격거리 또한 가급적 최대로 하는 것이 바람직하다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.75-82
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• 2010

Korea has made a plan to allocate CH 14~CH 51 (470 MHz~698 MHz) for DTV. This paper assumes that DTV operates on CH 51 (692 MHz~698 MHz) and CDMA system operates on CH 52 (698 MHz~704 MHz) in spare band. Minimum Coupling Loss (MCL) method to get protection distance and Spectrum Engineering Advanced Monte Carlo Analysis Tool (SEAMCAT) to get guard band through 5 % interference probability are used. The protection distance is required to be 665.67 km at close frequency offset of 698.625 MHz between DTV transmitter and CDMA Base Station (BS) receiver. The required guard band between DTV transmitter and CDMA Mobile Station (MS) receiver is 5 MHz for the worst case of rural environment. There is no serious impact between CDMA MS transmitter and DTV receiver. The required guard band between CDMA BS transmitter and DTV receiver is 6.25 MHz for the worst case of urban environment. The analysis results may offer a reference and be helpful for considering interference between DTV and other communication systems.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.17 no.4 s.107
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• pp.358-367
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• 2006

In this paper, a mathematical formulation of protection ratio and its calculation method are suggested for a radio relay system with diversity techniques. The analysis of protection ratio and its physical meaning have been performed for the space or frequency diversity system, and in particular protection ratios are reviewed in terms of the parameters of diversity improvement factor, which comprises antenna gain, separation distance between antennas, frequency and its difference between carriers, and distance. As one of simulated results, the co-channel protection ratio of 60 dB is obtained for the space diversity system regarding 6.2 GHz, 60 km, 64-QAM, and 25 m between antennas, which gives 15 dB less than the co-channel protection ratio of the non-space diversity system. In addition, the co-channel protection ratio for the frequency diversity system gives 64 dB in case of frequency offset of 0.5 GHz under the same conditions as the space diversity system, which brings about 11 dB less than the co-channel protection ratio of non-frequency diversity system. In consequency, it is interesting to note that the space diversity system is less sensitive to interference in comparison to the frequency diversity system and provides better quality of service for a given interference.

• Journal of Satellite, Information and Communications
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• v.10 no.3
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• pp.78-83
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• 2015

In this paper, when WLAN repeater of satellite communication package system as a novel wireless disaster communication network connected to LTE D2D mobile terminal, we analyzed radio channel interference from WLAN and WPAN system of adjacent same ISM band using Monte-Carlo method. In this study, WLAN cell radius was determined using Extended Hata Model considering practical environment, and simulated physical protection distance and density in the dense-mode to minimize interference from WLAN, Bluetooth, and ZigBee. Simulation results, WLAN repeater can be operated with 15 WLAN interferer over 130m distance, 23 Bluetooth interferer over 100m distance, and with 62 ZigBee interferer over 83m distance.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2011.11a
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• pp.11-14
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• 2011

산림 인접 시설은 산불의 발화원이자 주요 보호대상으로써, 이에 대한 관리와 소방 우선 순위의 결정은 인명과 재산의 보호를 위해 매우 중요하다고 할 수 있다. 본 연구에서는 산림 인접지의 정의를 위해, 산림으로부터 거리 별로 지역의 시설물의 분포를 분석하고, 해외분류 사례를 조사함으로써, 적절하고, 효과적인 산림 인접지 정의를 위한 기초자료를 제공하고자 하였다. 연구 결과 해외사례와 국내의 지형과 상황을 반영하였을 때, 산림으로부터 30m 혹은 50m의 이격거리 이내 지역을 인접지로 선정하는 것이 타당할 것으로 보이며, 실제 현장 조사 결과, 비화로 인해 피해를 발생한 사례를 제외하고, 전 피해 시설이 인접지 내에서 발생하여, 선정기준이 타당할 것으로 사료된다. 향후 추가적인 연구와 사례검증을 통한 연구를 통한 지속적인 보강이 필요할 것으로 사료된다.

• Ecology and Resilient Infrastructure
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• v.7 no.3
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• pp.160-170
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• 2020

Railroads and roads are typical linear projects, and their networks are expanding nationwide. To minimize the impact of their development on the environment, ecological disconnection due to the parallel lines of railroads and roads is to be avoided as much as possible. In this study, to examine the environmental impact of railroad and road development, the characteristics of railroads and roads and the differences between them were examined through a comparative analysis of key evaluation items. Based on the result, the road development, unlike the railroad project, suggests items for establishing an efficient land use plan and soil protection as the key evaluation items. There are no specific evaluation items and criteria that can be used to examine the environmental impact of railroad lines located adjacent to roads. In this study, eight evaluation items were suggested by reviewing the relevant literature. In particular, in the strategic environmental impact assessment stage, which examines the adequacy and location feasibility of the plan, the minimum separation distance criteria were proposed to examine in advance the environmental impact of railroads located adjacent to the existing roads. The distances were examined for the previously operated routes, and a distance of less than 200 m was suggested to minimize the environmental impact. The results were compared with those in other studies and analyzed. The results of this study can be used as a basis for examining alternative routes that can minimize the environmental impact of adjacent railroads and roads.