• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.2
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• pp.86-93
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• 2007

This paper proposes two fast calculation methods of ATC. These two methods evaluate ATC with thermal constraints(Thermal ATC) and ATC with voltage stability constraints(Voltage ATC) respectively. The ATC with thermal constraints was based on the linear incremental power flow to account for the line flow thermal loading effects when the n-1 security constraints were included. The ATC with voltage stability constraints used two-bus equivalents of the system to find the maximum load at a load bus before reaching the voltage stability problem. The methods were tested on the IEEE 30bus systems and the results obtained were compared with those found by some other methods.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.621-622
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• 2012

The thermal over-current relay or electronic motor protection relay is mostly used as the open-phase detection device of the three-phase motor or load. When the over-current or overheat of electric line is generated, it detects and operates circuit breaker, but there is the defect that the sensing speed is slow, the operation can be sometimes failed, and the precision is decreased. In order to improve these problems, this paper is proposed a new control circuit topology for open-phase protection using semiconductor devices. Therefore, the proposed open-phase protection device enhances the sensing speed and precision, and has the advantage of simple fitting in the three-phase motor control panel in the field, as it manufactures into small size and light weight.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.10a
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• pp.621-622
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• 2019

본 논문은 도심 환경하에서 운행 가능한 자율주행차량 시스템의 구현 방안에 대해 다루고 있다. 현대자동차가 주최한 2019 대학생 자율주행 경진대회는 도심 환경을 재현한 K-City 에서 열렸고, 도심 환경에서 발생할 수 있는 돌발 장애물 인지, 공사 구간 우회, 교차로 신호등 인지, 사고 차량 회피, 응급 차량에게 차선 양보 및 톨게이트 통과 등의 6 개의 미션을 자율주행차량이 무인운전으로 수행하는 것이었다. 이 대회를 위해 본 연구팀에서 개발한 자율주행 시스템은 리웍된 실제 차량에 탑재되어 대회장의 모든 주행 미션을 성공적으로 수행하였다.

• Korean Journal of Labor Studies
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• v.14 no.2
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• pp.201-229
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• 2008

본 논문에서는 노동자문화정치의 관점에서 파업을 새롭게 정의하고, 파업을 비롯한 노동자 문화실천의 정치적 효과를 분석하기 위한 방법론적 요소들을 검토하였다. 여기서 파업은 참여주체들의 다양한 사고와 합리성들을 중심으로 형성되고 확장되는 내재적인 정치의 장인 동시에, 다양한 기표적 실천들이 전개되는 문화정치의 장으로 정의되었다. 파업의 발생과 전개의 각 과정과 국면에 대한 문화정치적 분석 요소로서 장소성, 공간, 시간, 정서, 기호자원, 담론이 고려되었고, 이 요소들에 초점을 두고 민주노조 파업에서 드러나는 문화정치적 제약들을 H사 노조 사례를 통해 검토하였다. 문화정치적 제약들은 노동자 문화의 생산과 수용에서의 제약으로 드러난다. 노동자문화 관련 텍스트들의 분석과 조사 자료를 통해서 볼 때, 그것들은 첫째로 노동자 문화 활동가들의 생산 실천 상의 제약과 관련있고, 둘째로, 노동자 대중의 노동자 문화 수용 혹은 소비에서의 도구성과 시 공간 상의 제약과 관련있는 것을 확인했다. 본 논문은 이러한 제약들이 70년대 이후에서 90년대 전반에 이르는 시기와는 달리, 현 시기 노동운동의 문화적 자원들이 신기술과 사회문화적 변화에 걸맞게 변화 확장되지 못하고 오히려 축소된 데 기인한다고 추론하였다. 따라서 지속적인 운동의 조건과 기반을 능동적으로 조성하기 위해서는, 파업을 비롯한 노동자 문화의 생산과 수용 전반에 걸쳐서 작용하는 재현체계 상의 제약, 특히 기호자원의 한계라는 근본적인 제약을 넘어서기 위한 노동자 문화정치의 필요성이 제안되었으며, 문화실천에 몸담고 있는 문화활동가나 노조활동가들이 파업과 일상 활동 속에서 문화정치적 주제들을 찾아 이론화하고 정책에 반영하는 문화활동 방안이 제안되었다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.238-246
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• 2012

Once oil is spilled into marine environment, it experiences various weathering processes among which evaporation is the most dominant process in the initial stage of weathering. This study aimed to elucidate the effects of evaporation on the physicochemical properties of spilled oil using standardized laboratory experiments. Laboratory evaporation process was successfully reproduced using controlled rotary evaporation method. In case of Iranian Heavy crude (IHC), evaporation rate after 48 hours was $29.3{\pm}0.4%$ (n=40, p<0.001). Evaporation was simulated using ADIOS2 weathering model and the result was in agreement with laboratory experiment. Chemical composition changes of petroleum hydrocarbons including alkanes, polycyclic aromatic hydrocarbons (PAHs) and biomarkers by evaporation rate were also analyzed. As oil evaporated, low molecular weight alkanes and PAHs decreased, while biomakers showed conservative characteristics. Among biomarkers, $17{\alpha}(H)$, $21{\beta}(H)$-hopane was used for calculation of weathering rates, which matched with evaporative mass losses. Weathering rate calculation using hopane showed that stranded oils of weathering stage I (28.9%) and mesocosm oil weathering experiment till 5 days (26.5%) were mainly affected by evaporation process.

• Journal of Digital Convergence
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• v.15 no.11
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• pp.245-250
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• 2017

Flash floods is defined as the flooding of intense rainfall over a relatively small area that flows through river and valley rapidly in short time with no advance warning. So that it can cause damage property and casuality. This study is to establish the flash-flood warning system using 38 accident data, reported from the National Disaster Information Center and Land Surface Model(TOPLATS) between 2009 and 2012. Three variables were used in the Land Surface Model: precipitation, soil moisture, and surface runoff. The three variables of 6 hours preceding flash flood were reduced to 3 factors through factor analysis. Decision tree, random forest, Naive Bayes, Support Vector Machine, and logistic regression model are considered as big data methods. The prediction performance was evaluated by comparison of Accuracy, Kappa, TP Rate, FP Rate and F-Measure. The best method was suggested based on reproducibility evaluation at the each points of flash flood occurrence and predicted count versus actual count using 4 years data.

• Journal of Energy Engineering
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• v.25 no.4
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• pp.124-132
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• 2016

In order to estimate the effect of flow distributors connected to an upper nozzle of CMT(Core Makeup Tank) on the thermal-hydraulic characteristics in the tank, a simplified 2 inch Small Break Loss of Coolant Accident(SBLOCA) was simulated by skipping the decay power and Passive Residual Heat Removal System(PRHRS) actuation. The CMT is a part of safety injection systems in the SMART (System Integrated Modular Advanced Reactor). Each test was performed with reliable boundary conditions. It means that the pressure distribution is provided with repeatable and reproducible behavior during SBLOCA simulations. The maximum flow rates were achieved at around 350 seconds after the initial opening of the isolation valve installed in CMT. After a short period of decreased flow rate, it attained a steady injection flow rate after about 1,250 seconds. This unstable injection period of the CMT coolant is due to the condensation of steam injected into the upper part of CMT. The steady injection flow rate was about 8.4% higher with B-type distributor than that with A-type distributor. The gravity injection during hot condition tests were in good agreement with that during cold condition tests except for the early stages.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.8
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• pp.711-719
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• 2016

In this study, we derived an theoretical equation, using a simplified spring-mass model for the rolling stock, to obtain the overriding behavior of a leading vehicle, which is considered as the main factor in train accidents. To verify the derived equation, we created a simple 2D model based on the theoretical model, and a simple 3D model considering the characteristics of the power bogie. We then compared the theoretical results with the simulation results obtained using LS-DYNA. The maximum relative derivations in the vertical displacements at the first end-buffer, which is the most important point in overriding, were 3.5 [%] and 1.7 [%] between the two results. Further, we evaluated collision-induced overriding displacements using the theoretical equation for a rubber draft gear, a hydraulic buffer under various collision conditions. We have suggested a theoretical approach for the realization of overriding collision accidents or the energy absorption design of the front end of trains.

• Journal of the Society of Disaster Information
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• v.16 no.1
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• pp.96-110
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• 2020

Recently, due to global warming, it is easily exposed to various disasters such as fire, flood, and earthquake. In particular, large-scale disasters have continuously been occurring in crowded areas such as traditional markets, facilities for the elderly and children, and public facilities where various people stay. Purpose: This study aims to detect a fire occurred in crowded facilities early in the event to analyze and provide an optimal evacuation route using big data and advanced technology. Method: The researchers propose a new algorithm through context-aware 3D object model technology and A* algorithm optimization and propose a scenario-based optimal evacuation route selection technique. Result: Using the HPA* E algorithm, the evacuation simulation in the event of a fire was reproduced as a 3D model and the optimal evacuation route and evacuation time were calculated for each scenario. Conclusion: It is expected to reduce fatalities and injuries through the evacuation induction technique that enables evacuation of the building in the shortest path by analyzing in real-time via fire detection sensors that detects the temperature, flame, and smoke.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.10a
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• pp.465-467
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• 2015

This paper implements a dual-mode power strip controller (PSCtrl) with environmental sensors which cooperates with Android-based smartphones. According to the statistics on fires in housing facilities, unidentified electrical fires account for 23.4%. In order to reduce these fire accidents caused by user carelessness and protect life and property, smart power control techniques with improved user convenience are required. For this reason, the implemented dual-mode PSCtrl controls ON-OFF operations of a power strip in two ways (e.g. manual and automatic modes) by cooperating with Android-based smartphones provided with environmental data from light, temperature, and humidity sensors. In manual mode, users check environmental data displayed on Android-based smartphones, forcibly controlling the ON-OFF operations through the dual-mode PSCtrl, and in automatic mode, when environmental data exceeds the threshold set by users in advance, the dual-mode PSCtrl automatically controls the ON-OFF operations. Some experimental tests verify successful dual-mode operations of the implemented dual-mode PSCtrl.