• Nuclear Engineering and Technology
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• 제24권3호
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• pp.297-310
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• 1992

RELAP5/MOD3 5M5코드의 Apollo version을 이용하여 FLECHT SEASET 강제 재관수 실험을 평가하였다. 이 연구의 주 목적은 출력과 관수율의 초기값이 각기 다른 강제 재관수 조건하에서의 코드치 예측능력을 검사하는 것이 다. 많은 실험 중에서 8가지 경우에 대해 평가하였다. 이 8 가지 경우는 출력과 관수율외의 다른 초기 조건들은 유사한 값들을 갖는 것들이다. 또한 RELAP5/MOD3의 개선된 모델(model)들에 대해 여러 가지 민감도분석을 하였다. 즉 test section의 outlet junction에서의 Counter Current Flow Limit (CCFL) option의 영향과 heat structure와 interfacial drag의 계산에 미치는 grid modelling의 영향과 nodalization의 영향 및 time step size 의 영향등을 분석하였다. 이러한 민감도분석을 통해 코드의 예측능력을 향상시킬 수 있었다. 평가 결과로는 RELAP5/MOD3가 국소최대온도 (turn around temperature)와 그때의 시간 (turn around time)을 일반적으로 낮게 예측하나 관수율이 큰경우에는 국소최대온도를 약간 과대 평가 하였다. 또한 출력이 증가하고 관수율이 감소할수록 RELAP5/MOD3가 quenching을 상대적으로 지연시킴을 알 수 있었다.

• 한국도로학회논문집
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• 제19권2호
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• pp.153-165
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• 2017

PURPOSES : With the increasing number of older drivers in an aging society, there is a growing need for research and planning on traffic safety for the older drivers using an improved road geometry design. This study also proposed a modified urban road interchange design, which aims to keep the older drivers away from accident-prone and high-traffic areas of the city. METHODS : In this study, we examined accident data records of older drivers to identify accident-prone zones and intersections; we studied the road geometry at these zones and analyzed if it was an underlying cause for higher number of accidents. Based on the research and subsequent analysis, we suggested plans for improvement of road geometry design at these intersections. RESULTS :By studying historic data and analyzing factors that affect the likelihood of accidents of vehicles driven by older drivers and after studying suitable traffic accident prediction models, we identified the major variables that need to be modified at accident-prone intersections, such as the width of a left turn lane at an intersection and the radius of the right turn lane at a street corner. The results have a significance probability of less than 0.001 and a 95% confidence level. To improve safety at the identified intersection, this study suggests the installation of a left-turn-lane-shaped Positive Offset and a right-turn-lane-shaped Slip Lane concept and an adjustment of intervals between intersections.

• 과학기술학연구
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• 제12권2호
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• pp.33-79
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• 2012

이 논문의 첫 번째 목표는 참여적 전환이라는 최근 STS의 흐름 속에 미묘한 차이를 가지는 여러 입장들이 존재한다는 것을 드러내는 데 있다. 이러한 차이를 이해하는 것은 STS에서 논하는 과학기술 거버넌스와 위험 연구자들이 발전시킨 위험 거버넌스의 여러 모델 사이의 차이와 공통점, 그리고 접점을 모색해 보는 작업을 위해 매우 중요한 선행 작업이 될 수 있다. 이 논문의 두 번째 목표는 그 차이를 이해하기 위해서 2000년대가 아니라 1970년대와 1980년대로 거슬러 올라가서 당시 STS의 서로 다른 방법론들이 만들어지면서 나타났던 이론적인 차이가 2000년대 이후의 참여의 문제에서 상이한 입장의 근거가 되었음을 보이는 것이다. 모든 사상과 이론은 역사성을 가지고 있고, 실타래처럼 엉켜있는 그 역사적 과정을 풀어 헤쳐 보는 것은 지금의 차이의 연원을 이해하고, 궁극적으로 그 차이를 좁힐 수 있는 가능성을 모색하기 위해서 필요한 것이기 때문이다. 이 논문은 STS 참여적 전환의 '역사적 인식론'(historical epistemology)에 대한 것이며, 그 목표는 STS가 공유할 수 있는 미래의 정치적 인식론(political epistemology)을 모색해 보는 것이다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2005년도 하계학술대회 논문집 Vol.6
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• pp.623-626
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• 2005

Toward the practical applications, on operation of conduction-cooled HTS SMES at temperatures well below 77 K should be investigated, in order to take advantage of a greater critical current density of HTS and considerably reduce the size and weight of the system. Recently, research and development concerning application of the conduction-cooled HTS SMES that is easily movement are actively progressing in Korea. Electrical insulation under cryogenic temperature is a key and an important element in the application of this apparatus. Using multi wrapped copper by polyimide film for HIS SMES, the breakdown characteristics of models for turn-to-turn, that is surface contact model, were investigated under ac and impulse voltage at 77 K. A material that is Polyimide film (Kapton) 0.025 mm thickness is used for multi wrapping of the electrode. Statistical analysis of the results using Weibull distribution to examine the wrapping number effects on breakdown voltage under ac and impulse voltage in $LN_2$ was carried.

• Journal of Electrical Engineering and Technology
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• 제12권4호
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• pp.1566-1574
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• 2017

When the inter-turn short circuit (ITSC) fault occurs, the distortion of the magnetic field is serious. The motor loss variations of each part are obvious, and the motor temperature field is also affected. In order to obtain the influence of the ITSC fault on the motor temperature distribution, firstly, the normal and the fault finite element models of the permanent magnet synchronous motor (PMSM) were established. The magnetic density distribution and the eddy current density distribution were analyzed, and the mechanism of loss change was revealed. The effects of different forms and degrees of the fault on the loss were obtained. Based on the loss analysis, the motor temperature field calculation model was established, and the motor temperature change considering the loop current was analyzed. The influence of the fault on the motor temperature distribution was revealed. The sensitivity factors that limit the motor continuous operation were obtained. Finally, the correctness of the simulation was verified by experiments. The conclusions obtained are of great significance for the fault and high temperature demagnetization of the permanent magnet analysis.

• 한국도로학회논문집
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• 제19권5호
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• pp.143-151
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• 2017

PURPOSES : The purpose of this study is to develop models of accidents occurring at circular intersections related to the time of day and night and driver gender, and to provide countermeasures for safer circular intersections. METHODS : Seventy intersections built before 2008 were surveyed for inclusion in the modeling. Traffic accident data from 2008 to 2014 were collected from the TAAS data set of the Road Traffic Authority. Sixteen variables explaining the accidents including geometry and traffic volume were selected from the literature and seven multiple linear regression models were developed using SPSS 20.0. RESULTS : First, the null hypotheses, that the number of traffic accidents are not related to driver gender or time of day, were rejected at a 5% level of significance. Second, seven statistically significant accident models with $R^2$ value of 0.643-0.890 were developed. Third, in daytime models by gender, when the right-turn-only lane was selected as the common variable, the number of lanes, presence of driveways and speed humps, diagrammatic exit destination sign, and total entering traffic volume were evaluated as specific variables. Finally, in nighttime models by gender, when the diagrammatic exit destination sign was selected as the common variable, total entering traffic volume, presence of right-turn-only lanes, number of circulatory road way lanes, and presence of splitter islands and driveways were identified as specific variables. CONCLUSIONS:This study developed seven accident models and analyzed the common and specific variables by time of day and gender. The results suggest approaches to providing countermeasures for safer circular intersections.

• 대한교통학회지
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• 제26권1호
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• pp.145-153
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• 2008

기존의 최단경로 탐색모형들은 주로 경로의 단일 속성만을 고려한다. 그러나 실제로 통행자가 단일 속성만을 고려하여 경로를 선택하는 경우는 드물며, 대부분의 경로는 통행시간이나 경로길이 또는 통행자의 개인적인 선호 등과 같은 다양한 속성들이 종합적으로 고려되어 선택되어진다. 따라서 최적경로를 탐색하기 위해서는 이와 같은 다양한 속성들을 종합적으로 고려하여야 한다. 본 논문에서는 다양한 경로속성들을 고려하기 위하여 이산선택모형을 사용하여 네트워크의 노드별 효용을 산출하고, 이를 이용하여 최대의 효용을 가지는 경로를 탐색한다. 경로선택모형을 구축하기 위하여 경로선택에 영향을 미치는 요소들을 통행시간, 지체시간, 경로길이, 신호교차로수, 회전수, 전용도로의 포함비율 6가지로 선정하고, 모형의 모수를 추정하기 위한 현시선호자료를 구하기 위하여 서울시와 인접 신도시 간의 기종점 5개에 대한 경로를 선정하여 설문조사를 실시하였다. 경로선택모형의 함수형태로는 다항로짓모형을 사용하였으며, 모수추정 결과 통행시간과 신호 교차로수, 전용도로의 포함비율을 제외한 경로길이, 지체시간, 회전수를 가지고 모수를 추정한 결과가 통계적 유의성이 가장 높은 모형으로 도출되었다. 경로탐색 알고리즘으로는 도심부에서 U-turn과 회전제한의 반영이 가능한 기존의 수정형 덩굴망 알고리즘을 사용하였으며, 이를 구현하여 실제 네트워크에 적용하였다.

• International Journal of Control, Automation, and Systems
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• 제3권2호
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• pp.173-182
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• 2005

In this paper, a target tracking algorithm for tracking maneuvering vehicles is presented. The overall algorithm belongs to the category of an interacting multiple-model (IMM) algorithm used to detect multiple targets using fused information from multiple sensors. First, two kinematic models are derived: a constant velocity model for linear motions, and a constant-speed turn model for curvilinear motions. Fpr the constant-speed turn model, a nonlinear information filter is used in place of the extended Kalman filter. Being equivalent to the Kalman filter (KF) algebraically, the information filter is extended to N-sensor distributed dynamic systems. The model-matched filter used in multi-sensor environments takes the form of a federated nonlinear information filter. In multi-sensor environments, the information-based filter is easier to decentralize, initialize, and fuse than a KF-based filter. In this paper, the structural features and information sharing principle of the federated information filter are discussed. The performance of the suggested algorithm using a Monte Carlo simulation under the two patterns is evaluated.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 추계학술대회 논문집
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• pp.93-95
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• 2007

Studies on ski-end shape control at the top end of rolling plate in heavy thick plate mill by using FEM analysis and measuring system have been performed. Plate shape behaviour at the top-end on rolling by the two different methods in finishing rolling process has been observed. One is to minimize the height of ski-end by using pass line based on the relational model between shape factor and pick-up and the other one is to prevent turn down problem caused by the impact between table roller and down bended plate on rolling by using roll speed difference. To minimize the height of ski-end, the prediction models based on the FEM analysis and measuring data was developed. The control method of ski - end shape on finishing rolling process was applied in actual mill and the height of ski-end was reduced by about 50% compared with conventional operation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1669-1674
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• 2004

In this paper, a nonlinear information filter (IF) for curvilinear motions in an interacting multiple model (IMM) algorithm to track a maneuvering vehicle on a road is investigated. Driving patterns of vehicles on a road are modeled as stochastic hybrid systems. In order to track the maneuvering vehicles, two kinematic models are derived: A constant velocity model for linear motions and a constant-speed turn model for curvilinear motions. For the constant-speed turn model, a nonlinear IF is used in place of the extended Kalman filter in nonlinear systems. The suggested algorithm reduces the root mean squares error for linear motions and rapidly detects possible turning motions.