• 한국자동차공학회논문집
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• 제16권2호
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• pp.136-142
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• 2008

Thermal management of a junction box of a passenger car has recently become more challenging due to its smaller size and larger current capacity. Thus, it is essential to perform the thermal optimization of a junction box in its design on an early stage of vehicle design. In this study, 3 dimensional CFD simulation with experimental measurement has been done to study for better thermal management of the junction box. First, the study of thermal characteristics of electric relays in the junction box has revealed that each surface of the relay has very different thermal resistance. In addition, an idea to install a cooling fan on the junction box has been studied and it was found that the forced cooling method was not effective on the system to keep the thermal resistance to the reasonable level of the junction box. Finally, the effect of external flows around the junction box on the temperatures of the relays, fuses, etc. has been studied and the result shows that the installation of the junction box at the proper place in an engine room can avoid any unnecessary overdesign in thermal management.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.1334-1338
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• 2005

A limit switch box is used for an indicator of a valve actuator. This device indicates an opening and closing of a valve or a throttle in the valve actuator. In a ship, equipments require safety and robustness because of a rough environment and a specific condition during a voyage. However, the limit switch box has been used in an indoor environment generally. This study developed a new limit switch box which can be used at an outdoor environment. This study designed the new limit switch box. The housing of the limit switch box was made by an aluminum die cast method with surface painting after anodizing or chromate coating. In order to evaluate the endurance of the housing, the endurance tests against salt water have been conducted. Experiment results showed that the proposed device provides a reliable performance against salt water.

• 대한수학회지
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• 제33권4호
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• pp.955-982
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• 1996

In surface compression applications, one of the main issues is how to efficiently store and calculate the computer representation of certain surfaces. This leads us to consider a nonlinear approximation by box splines with free knots since, for instance, the nonlinear method based on wavelet decomposition gives efficient compression and recovery algorithms for such surfaces (cf. [12]).

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.436-441
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• 1997

A Formulation based on macroelement concept is developed to analysis the prestressed concrete box girder bridges. The proposed method enables to model the arbitrary shapes and boundary conditions of prestressed concrete box girder bridges. The validity of the algoriyhm is demonstrated through comparisons with other results.

• 대한토목학회논문집
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• 제26권4A호
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• pp.693-700
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• 2006

정적 손상 탐지방법은 동적 방법과 비교해서 실제 적용하기에 단순하고 효과적이다. 본 논문에서는 정적데이타를 이용하는 방법으로 변위, 처짐각, 곡률을 이용한 강박스 교량의 손상 탐지 방법에 대해서 연구하였다. 변위는 유한요소 해석에서 얻고, 처짐각과 곡률은 변위로부터 중앙차분법을 이용하여 구하였다. 손상되지 않은 경우와 손상된 경우의 응답차의 절대값으로 손상의 위치를 탐지하였다. 손상은 박스의 모서리 균열을 singular 요소를 사용하여 직접 모델링하여, 실질적인 거동을 분석하였다. 해석 결과 응답차의 절대값으로 손상의 위치를 탐지하기에 매우 효과적이었다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제15권1호
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• pp.66-72
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• 2010

The partitioning tracer method is to estimate the residual saturation of nonaqueous phase liquid (NAPL) in soils by analyzing tracer's retardation induced by the reversible partitioning of tracer with NAPL. This study is to estimate the residual diesel saturation in soils using the partitioning tracer method. Two-dimensional soil box was used to represent the 2-dimensional flows of groundwater and tracer solution in the saturated aquifer, and the soil box was filled with soil and then saturated with water. The residual diesel saturation was induced in saturated soil, and the partitioning tracer method was applied. The results from batch-partitioning experiment indicated that the diesel-water partitioning was linear with respect to tracer's concentration, and the partition coefficient of tracer between diesel and water was measured by their linearities. The groundwater flow in the saturated aquifer was simulated in the 2-dimensional soil box, and the residual diesel contamination was visually identified. The results from the partitioning tracer method with or without diesel in soils confirmed that 4-methyl-2-pentanol, 2-ethyl-1-butanol and 1-hexanol, can be used as a detecting method for diesel contamination. By the accuracies of estimations for diesel contamination using the partitioning tracer method, 2-ethyl-1- butanol showed the highest accuracy with 83%.

• 한국수자원학회논문집
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• 제36권3호
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• pp.481-494
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• 2003

암거흐름은 지형 및 수리조건에 따라 복잡하고, 다양한 흐름특성을 나타내고 있으며, 이로인해 암거설계는 주로 모노그래프를 이용한 설계방식을 채택하고 있는 실정이다. 이는 개수로 암거의 경우 입구부에서의 수심을 산정하여야 하는 어려움과 복잡한 흐름특성 때문인 것으로 사료된다. 본 연구에서는 사각형 암거 입구부에서의 수심을 베르누이 방정식을 이용하여 결정하였으며, 이를 적용하여 여러 가지 형태의 흐름특성에 따른 암거 설계기준식을 개발하였다. 또한 설계항목을 암거경사${\cdot}$유량${\cdot}$폭${\cdot}$높이로 구분하여 각각의 경우에 대하여 양해법 산정식을 개발하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.989-995
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• 2010

This paper is focused on a simplified measurement of rail irregularity by some axle-box accelerometers for high-speed rail condition monitoring with in-service high-speed trains. Generally, the rail condition monitoring has been done by a special railway inspection vehicle with a 10m versine method. But, the monitoring method needs some expensive measurement system, and have been performed only at night due to its speed limit. In this research, a simplified measurement of rail irregularity using axle-box accelerometers is proposed to monitor the rail condition with in-service high-speed trains. The acceleration is measured by using two accelerometers on a axle-box, and stored in an on-board data acquisition system. The displacement is estimated from the acceleration data by a combination of Kalman filter and the frequency selective filter. The estimated results are compared with the measurement from a laser rail inspection system which is near the axle-box. From the comparison, the proposed method shows promise as a tool for the simplified measurement of rail irregularity at high-speed.

• 로봇학회논문지
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• 제17권4호
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• pp.417-424
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• 2022

In this paper, the developed trunk cargo unloading automation system is introduced, and the RGB-D sensor-based box loading situation recognition method and unloading plan applied to this system are suggested. First of all, it is necessary to recognize the position of the box in a truck. To do this, we first apply CNN-based YOLO, which can recognize objects in RGB images in real-time. Then, the normal vector of the center of the box is obtained using the depth image to reduce misrecognition in parts other than the box, and the inner wall of the truck in an image is removed. And a method of classifying the layers of the boxes according to the distance using the recognized depth information of the boxes is suggested. Given the coordinates of the boxes on the nearest layer, a method of generating the optimal path to take out the boxes the fastest using this information is introduced. In addition, kinematic analysis is performed to move the conveyor to the position of the box to be taken out of the truck, and kinematic analysis is also performed to control the robot arm that takes out the boxes. Finally, the effectiveness of the developed system and algorithm through a test bed is proved.

• 정보보호학회논문지
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• 제32권3호
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• pp.465-475
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• 2022

코로나19의 영향으로 사람들은 편리함, 건강 등에 관심을 두게 되었고, 이를 도와주는 IoT 기기의 사용량은 늘어나고 있다. 리소스가 제한적이지만 민감한 정보를 다뤄야 하는 IoT 기기들에 경량 보안요소를 내장하기 위해서는 경량 S-box의 개발이 필수적이다. 2021년 이전까지 경량 4-bit S-box는 휴리스틱 방법으로 개발하고, 더 큰 크기의 경량 S-box는 확장구조 혹은 같은 연산을 반복하여 개발하는 것이 일반적이었다. 그러나 2022년 1월, MISTY 확장구조로 생성한 S-box보다 더 좋은 차분 균일성(Differential uniformity)과 선형성(Linearity)을 갖는 8-bit S-box를 찾을 수 있는 휴리스틱 알고리즘을 제안한 논문이 게재되었다[1]. 해당 논문에서 제안한 휴리스틱 알고리즘은 AND 연산자를 한 개씩 추가하면서 S-box를 생성하는데, AND 연산자를 추가할 때마다 차분 균일성을 계산하여 원하는 기준에 도달할 수 없는 S-box를 사전에 제거하는 방식을 사용한다. 본 논문에서는 이 휴리스틱 알고리즘의 성능을 향상한다. 차분 균일성뿐만 아니라 또 다른 차분성질을 사용하여 사전제거하는 양을 늘리고, 선형성을 계산하여 사전제거하는 프로세스를 추가함으로써 차분안전성뿐만 아니라 선형안전성까지도 동시에 만족할 수 있게 한다.