• 한국가스학회지
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• 제9권2호
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• pp.28-33
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• 2005

화학 산업시설은 위험 물질을 대규모로 취급하기 때문에 사고 발생 시 사업장 근로자뿐만 아니라 사업장 주변의 주민들에게까지 피해를 끼칠 수 있다. 이러한 대형사고를 효과적으로 제어하고 대응하기 위해서 국내 화학산업단지의 위험성을 객관적으로 수치화하여 묘사할 수 있는 위험도 표현 시스템의 개발이 필요하다. 이에 본 연구에서는 사업장별 위험도를 전자 지도 망에 표기하여 실제 위험성을 파악하고 파악된 위험성을 감소시킬 수 있는 대책을 강구 할 수 있도록 위험도 표현 시스템(S/W)을 개발하였다.

• International Journal of Control, Automation, and Systems
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• 제5권3호
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• pp.295-306
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• 2007

It is well known that mathematical solutions for multi-agent planning problems are very difficult to obtain due to the complexity of mutual interactions among multi-agents. Most of the past research results are thus based on the probabilistic completeness. However, the practicality and effectiveness of the solution from the probabilistic completeness is significantly reduced by heavy computational burden. In this paper, we propose a practically applicable solution technique for multi-agent planning problems, which assures a reasonable computation time and a real world application for more than 3 multi-agents, for the case of general shaped paths in agent movement. First, to reduce the computation time, an extended collision map is developed and utilized for detecting potential collisions and obtaining collision-free solutions for multi-agents. Second, a priority for multi-agents is considered for successive and interactive modifications of the agent movements with lower priority. Various solutions using speed reduction and time delay of the relevant agents are investigated and compared in terms of the computation time. A practical implementation is finally provided for three different types of agents to emphasize the effectiveness of the proposed interactive approach to multi-agent planning problems.

• 제어로봇시스템학회논문지
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• 제15권5호
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• pp.519-524
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• 2009

This paper describes a new sensor system for 3D environment perception using stereo structured infrared light sources and a camera. Environment and obstacle sensing is the key issue for mobile robot localization and navigation. Laser scanners and infrared scanners cover $180^{\circ}$ and are accurate but too expensive. Those sensors use rotating light beams so that the range measurements are constrained on a plane. 3D measurements are much more useful in many ways for obstacle detection, map building and localization. Stereo vision is very common way of getting the depth information of 3D environment. However, it requires that the correspondence should be clearly identified and it also heavily depends on the light condition of the environment. Instead of using stereo camera, monocular camera and two projected infrared light sources are used in order to reduce the effects of the ambient light while getting 3D depth map. Modeling of the projected light pattern enabled precise estimation of the range. Two successive captures of the image with left and right infrared light projection provide several benefits, which include wider area of depth measurement, higher spatial resolution and the visibility perception.

• Nuclear Engineering and Technology
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• 제48권1호
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• pp.259-267
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• 2016

Most manufacturing processes, including welding, create residual stresses. Residual stresses can reduce material strength and cause fractures. For estimating the reliability and aging of a welded structure, residual stresses should be evaluated as precisely as possible. Optical techniques such as holographic interferometry, electronic speckle pattern interferometry (ESPI), Moire interferometry, and shearography are noncontact means of measuring residual stresses. Among optical techniques, ESPI is typically used as a nondestructive measurement technique of in-plane displacement, such as stress and strain, and out-of-plane displacement, such as vibration and bending. In this study, ESPI was used to measure the residual stress on the welded part of butt-welded American Society for Testing and Materials (ASTM) A36 specimens with $CO_2$ welding. Four types of specimens, base metal specimen (BSP), tensile specimen including welded part (TSP), compression specimen including welded part (CSP), and annealed tensile specimen including welded part (ATSP), were tested. BSP was used to obtain the elastic modulus of a base metal. TSP and CSP were used to compare residual stresses under tensile and compressive loading conditions. ATSP was used to confirm the effect of heat treatment. Residual stresses on the welded parts of specimens were obtained from the phase map images obtained by ESPI. The results confirmed that residual stresses of welded parts can be measured by ESPI.

• 한국측량학회지
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• 제20권2호
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• pp.191-197
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• 2002

최근 컴퓨터 관련분야의 눈부신 발전과 더불어 고해상도 디지털 카메라의 개발은 수치사진측량분야에서도 보다 정확한 위치측정을 가능하게 하였으며, 이의 활용에 관심이 집중되고 있다. 본 연구는 사진실측을 통해 근대문화유산 건축물의 수치도면을 작성함에 있어서 수치영상을 이용한 영상선점 기법을 토대로 보다 손쉽게 3차원 위치측정이 가능한 알고리즘을 개발하고 시스템을 구축하여 기준점 측량작업 및 촬영조건 제약을 획기적으로 줄일 수 있었으며 보다 효율적으로 건축물의 수치도면화 및 3차원 모델을 구축할 수 있었다.

• 한국정보통신학회논문지
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• 제8권4호
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• pp.950-954
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• 2004

컴퓨터와 통신 기술의 빠른 발전으로 모바일 인터넷 서비스의 요구가 급격히 증대하고 있다. 그러나 모바일 벡터 지도 서비스 환경에서의 가장 큰 걸림돌은 큰 데이터 용량과 제한된 대역폭이다. 많은 가능한 해결방안 중 공간 데이터 압축 기법이 대역폭과 클라이언트에서의 대기 시간 축소에 공헌할 수 있을 것으로 기대된다. 본 논문은 공간 데이터를 압축하기 위한 2가지 기법을 제시한다. 하나는 공간 객체별로 기준 좌표 및 상대 좌표를 전송하는 상대좌표 변환 압축 기법이고 또 하나는 클라이언트 좌표로 서버에서 미리 좌표 변환하는 클라이언트좌표 변환 압축 기법이다. 이 두 압축 기법은 압축 효율과 응답시간을 측정하여 평가할 수 있다.

• 한국정보통신학회논문지
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• 제13권3호
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• pp.556-563
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• 2009

MIP의 확장 버전인 HMIP는 동일 지역 내에서 이동할 경우 외부 시그널링을 줄일 수 있다. 그러나 다른 MAP 영역으로 이동하는 매크로 핸드오버일 경우 바인딩 갱신을 위한 많은 시그널링으로 인해 전송 지연과 패킷 손실이 발생한다. 이를 해결하기 위해 계층적 구조에서 주소 보장과 선택적 버퍼링을 이용한 핸드오버를 제안한다. 이 방식은 매크로 핸드오버가 발생할 때 패킷 손실과 전송 지연을 줄이고 QoS가 높은 트래픽이나 실시간 멀티미디어 트래픽의 전송에 우수한 성능을 제공한다. 시뮬레이션 결과는 제안하는 핸드오버가 기존 핸드오버보다 전송 지연과 패킷 손실에 대하여 크게 감소함을 보였다.

• International Journal of Automotive Technology
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• 제7권3호
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• pp.361-367
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• 2006

This paper describes a novel stereo vision based localization of free parking site, which recognizes the target position of automatic parking system. Pixel structure classification and feature based stereo matching extract the 3D information of parking site in real time. The pixel structure represents intensity configuration around a pixel and the feature based stereo matching uses step-by-step investigation strategy to reduce computational load. This paper considers only parking site divided by marking, which is generally drawn according to relevant standards. Parking site marking is separated by plane surface constraint and is transformed into bird's eye view, on which template matching is performed to determine the location of parking site. Obstacle depth map, which is generated from the disparity of adjacent vehicles, can be used as the guideline of template matching by limiting search range and orientation. Proposed method using both the obstacle depth map and the bird's eye view of parking site marking increases operation speed and robustness to visual noise by effectively limiting search range.

• 대한원격탐사학회지
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• 제25권3호
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• pp.295-309
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• 2009

In this study, an iterative maximum a posteriori (MAP) approach using a Bayesian model of Markovrandom field (MRF) was proposed for despeckling images that contains speckle. Image process is assumed to combine the random fields associated with the observed intensity process and the image texture process respectively. The objective measure for determining the optimal restoration of this "double compound stochastic" image process is based on Bayes' theorem, and the MAP estimation employs the Point-Jacobian iteration to obtain the optimal solution. In the proposed algorithm, MRF is used to quantify the spatial interaction probabilistically, that is, to provide a type of prior information on the image texture and the neighbor window of any size is defined for contextual information on a local region. However, the window of a certain size would result in using wrong information for the estimation from adjacent regions with different characteristics at the pixels close to or on boundary. To overcome this problem, the new method is designed to use less information from more distant neighbors as the pixel is closer to boundary. It can reduce the possibility to involve the pixel values of adjacent region with different characteristics. The proximity to boundary is estimated using a non-uniformity measurement based on standard deviation of local region. The new scheme has been extensively evaluated using simulation data, and the experimental results show a considerable improvement in despeckling the images that contain speckle.

• International Journal of Advanced Culture Technology
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• 제11권1호
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• pp.337-342
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• 2023

Since the electric vehicle uses an electric motor, problems have arisen as the driver hears the inherent noise of the motor or external noise, which was not a problem in the past, due to the overall lower noise environment than when using an internal combustion engine. Therefore, the purpose of this paper is to reduce the noise and vibration of electric motors for electric vehicles, and recently, to increase the speed of high-power, high-efficiency electric motors in a small size, and to develop low-noise motors, IPM motors are applied to produce 35KW electric motors for electric vehicles. A motor for low noise was designed and implemented. N-T Curve and efficiency map were confirmed as the final result of developing a 35KW low-noise motor for electric vehicles by applying the IPM motor applied in this paper. Based on 3500 rpm, Max Torque [Nm]: 121.15, Max Power [KW]: 44.04, and Max Efficiency [%]: 97.65, showing high efficiency.