• Earthquakes and Structures
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• 제21권5호
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• pp.505-514
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• 2021

A formulation based on structural reliability and cost effectiveness is proposed to provide recommendations to select the best retrofit strategy for schools with reinforced concrete frames and masonry walls, among three proposed alternatives. The cost calculation includes the retrofit cost and the expected costs of failure consequences. Also, the uncertainty of the seismic hazard is considered for each school site. The formulation identifies the potential failure modes, among shear and bending forces for beams, and flexure-compression forces for columns, for each school, and the seismic damages suffered by the schools after the earthquake of September 17, 2017 are taken into account to calibrate the damaged conditions per school. The school safety level is measured through its global failure probability, instead of only the local failure probability. The proposed retrofit alternatives are appraised in terms of the cost/benefit balance under future earthquakes, for the respective site seismic hazard, as opposed to the current practice of just restoring the structure original resistance. The best retrofit is the one that corresponds to the minimum value of the expected life cycle cost. The study, with further developments, may be used to develop general recommendations to retrofit schools located at seismic zones.

• 한국항해항만학회지
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• 제44권6호
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• pp.524-533
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• 2020

자유무역지역제도는 1970년부터 제조업 중심으로 산업단지형 자유무역지역에서 시행되어 왔으며, 입주기업에게 조세 감면 및 규제 완화 등의 혜택을 제공함으로써 외국인 투자를 유치하고 무역물동량 증가를 창출하는데 큰 역할을 해 왔다. 그러나 산업단지형 자유무역지역의 외국인투자 유치실적이 현저히 떨어지고 있는 실정이다. 한편으로, 항만형 자유무역지역에서는 항만 물동량의 증가로 발전 가능성을 크게 내포하고 있어, 현재까지 제조업 중심으로 시행되어 온 자유무역지역제도의 발전 방향을 점검해 볼 필요가 있다. 본 논문에서는 자유무역지역의 역할과 운영 실태를 파악하고 이에 대한 문제점을 도출하고자 한다. 이를 위해, 항만형 자유무역지역에 특화된 비즈니스 모델을 분석하여 문제점을 파악하고, 물품보관을 목적으로 한 내국 물품의 관세영역으로 재반출에 대한 제도 개선방안을 제시하며, 간이 시뮬레이션을 통하여 개선방안에 대한 효과를 분석하였다. 본 연구에서 제시한 제도 개선으로 자유무역지역을 국제물류허브 및 글로벌배송센터로 이용하고자 하는 외국기업을 유치하는데 매우 중요한 요소로 작용할 것이다.

• Journal of Electrical Engineering and Technology
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• 제6권6호
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• pp.750-759
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• 2011

This paper focuses on the control of bidirectional power flow in the electric shipboard power systems, especially in the Medium-Voltage Direct Current (MVDC) shipboard power system. Bidirectional power control between the main MVDC bus and the local zones can improve the energy efficiency and control flexibility of electric ship systems. However, since the MVDC system contains various nonlinear loads such as pulsed power load and radar in various subsystems, the voltage of the MVDC and the local zones varies significantly. This voltage variation affects the control performance of the bidirectional DC-DC converters as exogenous disturbances. To improve the control performance regardless of uncertainties and disturbances, this paper proposes a novel controller design method of the bidirectional DC-DC converters using $L_1$ control theory and intelligent optimization algorithm. The performance of the proposed method is verified via large-scale real-time digital simulation of a notional shipboard MVDC power system.

• 한국방재학회 논문집
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• 제8권4호
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• pp.31-38
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• 2008

본 연구는 어린이 교통사고의 심각성과 현재 활발하게 추진되고 있는 어린이보호구역의 가변속도표출기(drive feedback sign, 이하 DFS) 설치 및 운영을 배경으로 부천시 어린이보호구역의 DFS 사전 사후 속도조사를 통해 평균속도감속이 교통사고 감소율에 미치는 영향을 조사하여 부천시의 각 초등학교 대상지별 평균속도감소에 따른 교통사고 감소율을 예측한다. 그리고 조사 결과를 바탕으로 부천시 어린이보호구역 지정 초등학교의 DFS운영에 따른 교통사고로 인한 인적재난 감소효과를 알아보는데 그 목적이 있다.

• Transactions on Electrical and Electronic Materials
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• 제7권2호
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• pp.53-57
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• 2006

In this paper, a Symmetric Dual-gate Single-Si TFT, which includes three split floating n+ zones, is simulated. This structure drastically reduces the kink-effect and improves the on-current. This is due to the separated floating n+ zones, the transistor channel region is split into four zones with different lengths defined by a floating n+ region. This structure allows effective reduction in the kink-effect, depending on thy length of the two sub-channels. The on-current of the proposed dual-gate structure is 0.9 mA, while that of the conventional dual-gate structure is 0.5 mA, at both 12 V drain and 7 V gate voltages. This result shows an 80% enhancement in on-current. In addition, the reduction of electric field in the channel region compared to a conventional single-gate TFT and the reduction of the output conductance in the saturation region, is observed. In addition, the reduction in hole concentration, in the channel region, in order for effectively reducing the kink-effect, is also confirmed.

• Environmental Engineering Research
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• 제19권3호
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• pp.197-203
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• 2014

This study estimated spatial and seasonal variation of water quality to understand characteristics of Nakdong river basin, Korea. All together 11 parameters (discharge, water temperature, dissolved oxygen, 5-day biochemical oxygen demand, chemical oxygen demand, pH, suspended solids, electrical conductivity, total nitrogen, total phosphorus, and total organic carbon) at 22 different sites for the period of 2003-2011 were analyzed using multivariate statistical techniques (cluster analysis, principal component analysis and factor analysis). Hierarchical cluster analysis grouped whole river basin into three zones, i.e., relatively less polluted (LP), medium polluted (MP) and highly polluted (HP) based on similarity of water quality characteristics. The results of factor analysis/principal component analysis explained up to 83.0%, 81.7% and 82.7% of total variance in water quality data of LP, MP, and HP zones, respectively. The rotated components of PCA obtained from factor analysis indicate that the parameters responsible for water quality variations were mainly related to discharge and total pollution loads (non-point pollution source) in LP, MP and HP areas; organic and nutrient pollution in LP and HP zones; and temperature, DO and TN in LP zone. This study demonstrates the usefulness of multivariate statistical techniques for analysis and interpretation of multi-parameter, multi-location and multi-year data sets.

• 분석과학
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• 제34권2호
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• pp.56-67
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• 2021

Due to the difficulty of grading visualized fingerprints with previously known evaluation methods for the comparison of split fingerprints, a preliminary study was performed with the densitometric image analysis (DIA) method as a potential quantitative and supplementary evaluation method. Each image of inked split fingerprints was divided into 4 zones for analysis. Weekly intra- and inter- analysis by two analysts with three whole fingerprints that were constructed by combining inked split fingerprints showed that the average area values and the ranges of difference fluctuation were not significantly different between strong fingerprints and strong-weak pairs, while they were different in weak fingerprints and weak-weak pairs. In the case of weak fingerprints, the exact acquisition of ridges was difficult and this seemed to influence the results. An additional study is needed for the improved reliability using DIA method with weak fingerprints such as 8 zones division rather than 4 zones. In addition, the analysis results performed by several analysts at different times should be used to improve the reliability of the analysis method further. Based on the above result, it can be judged that utilizing the DIA method as a secondary evaluation method of the existing scoring system would be effective with the additional studies especially on weak fingerprints.

• Steel and Composite Structures
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• 제47권4호
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• pp.451-454
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• 2023

Landslides are one of the natural disasters that cause a lot of financial and human losses every year It will be all over the world. China, especially. The Mainland China can be divided into 12 zones, including 4 high susceptibility zones, 7 medium susceptibility zones and 1 low susceptibility zone, according to landslide proneness. Climate and physiography are always at risk of landslides. The purpose of this research is to prepare a landslide hazard map using the Hierarchical Analysis Process method. In the GIS environment, it is in a part of China watershed. In order to prepare a landslide hazard map, first with Field studies, a distribution map of landslides in the area and then a map of factors affecting landslides were prepared. In the next stage, the factors are prioritized using expert opinion and hierarchical analysis process and nine factors including height, slope, slope direction, geological units, land use, distance from Waterway, distance from the road, distance from the fault and rainfall map were selected as effective factors. Then Landslide risk zoning in the region was done using the hierarchical analysis process model. The results showed that the three factors of geological units, distance from the road and slope are the most important have had an effect on the occurrence of landslides in the region, while the two factors of fault and rainfall have the least effect The landslide occurred in the region.

• 한국정보통신학회논문지
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• 제26권8호
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• pp.1248-1254
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• 2022

스쿨존에서 교통사고를 사전에 예방하려고 노력하고 있다. 하지만, 스쿨존 내 교통사고는 계속 발생하고 있다. 운전자가 어린이보호구역 내 상황 정보를 미리 알 수 있으면, 사고를 줄일 수 있다. 본 논문에서는 스쿨존 내 사각지대를 없애는 카메라, 사전 교통정보를 수집할 수 있는 번호인식 카메라 시스템을 설계한다. 차량속도 및 보행자를 인식하는 LIDAR 시스템을 개선하여 설계한다. 카메라 및 LIDAR에서 인식된 보행자 및 차량 영상 정보를 수집하고 가공하여, 인공지능 시계열 분석 및 인공지능 알고리즘을 적용한다. 본 논문에서 제안한 딥러닝으로 학습된 인공지능 교통사고 예방 시스템은, 스쿨존 진입 전 차량 내 모바일 장치에 스쿨존의 정보를 운전자에게 전달하는 강제 푸시서비스를 한다. 그리고 LED 안내판에 스쿨존 교통정보를 알람으로 제공한다.

• 자동차안전학회지
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• 제15권3호
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• pp.7-16
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• 2023

In 2019, a child died by a school zone traffic accident in Asan, Chungcheongnam-do, the Republic of Korea. Just after the accident, under the name of the "Minsik Law", the Road Traffic Act and the Specific Crime Aggravated Punishment Act were partially revised and went into effect in Korea on March 25, 2020. The new Korean law providing for harsh penalties is designed to reduce automobile accidents in school zones. However, the penalties under the new law seems to be unconstitutionally and unduly harsh. Under the new law, a negligent driver who kills a child at a school zone could be sentenced to indefinite imprisonment, or imprisonment for 3 years or more. The criminal responsibility of a negligent driver at a school zone is the same as serious intentional felonies such as rape, robbery, abandonment resulting in death. Also, even in the case of a school zone accident, if an accident driver complies with the speed limit and other traffic laws and it is impossible to avoid the accident, the driver should not be punished. So, in order to meet the principle of proportionality, the new Korean law should be revised again. In order to find out the appropriate level and punishment method for drivers who cause accidents in school zones, this thesis will compare and analyze the laws of Korea with those of the United States, Germany, and Japan. This paper also reviews the decision of the Constitutional Court of the Republic of Korea in February 2023 that the "Minsik Law" was constitutional. Based on these analyses, this thesis seeks the direction and amendments to properly revise Korean law. In addition, this thesis is intended to present exemplary measures to improve the school zone safety.