• Journal of the KSME
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• v.32 no.10
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• pp.837-846
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• 1992

고령화 혹은 국제화와 같은 변화 양상은 다가오는 21세기의 새 시대를 가치기준에서 뿐만 아니라 사회환경까지도 새로운 것을 추구하도록 요구해 가고 있다. 이것은 도로교통에 있어서도 마찬 가지로 지금까지 양적인 팽창 위주로 전개되던 것이 효율을 중시하지 않으면 안 되게 되었으며 특히 20세기 후반들어 반도체 기술과 함께 급격한 발전을 거듭하고 있는 컴퓨터 기술은 정보 통신 기술과 함께 도로교통의 새로운 장을 열어 갈 것으로 예측된다. 21세기의 도로 교통을 생 각할 때, 차량 보급 대수의 증가와 함께 지금도 교통사고가 커다란 사회 문제로 대두되고 있는 추세로 볼 때, 중심이 되는 단어는 역시 '안전'과 '환경'이겠지만 그 가운데에도 교통 사고의 저 감은 무엇보다 시급한 과제라 할 수 있으며 대기 오염을 비롯한 물리적 환경의 개선과 보다 원 활하고 쾌적하게 달릴 수 있는 교통 환경의 실현도 중요한 과제가 될 것이다. 이 글에서는 이 러한 관점에서 21세기의 도로교통과 이를 이루어가기 위한 기술적 과제들을 살펴보고자 한다.

• Journal of Korea Multimedia Society
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• v.10 no.4
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• pp.483-491
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• 2007

This paper proposes a Situation Simulation Framework for implementing computer game and describes the possibility of analyzing game with unfolding situation. In last few years game systems have been evolving from the performance of physical engine, network traffic in the on line game to the representation of rendering physical phenomena. In computer game, a situation hierarchy structure which allows the designer for simulating high-level specifications of game structure. Logically simulated environment is created by defining situations and events based on hierarchy structure of the situation. We classify events into explicit event is occurred by user and implicit event is occurred by system. Our study defines the existence of objects is the most prevalent factor applied to any event in game world. The advantages of this approach are able to allow for providing the conceptual design for simulation game and analyzing the situation in the game world. And this method allows us to decrease the complexity of system design and abstraction modeling for the simulation game. Specially, the introduction of the definition of events allows us to approach game design in a structural manner rather than by their classification. The proposed method was implemented in the "Shooting BaDuk" among games.

• The Journal of Korean Institute for Practical Engineering Education
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• v.2 no.2
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• pp.55-60
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• 2010

We usually encounter Electro-magnetics phenomenons and only feel some part of that, but it is hard to feel it visually. Moreover understanding physically and quantitatively is not a easy work. These electrostatic field theory, magnetostatic field theory and interchange magnetic field theory combined with electromagnetic field are formulated experimentally and theoretically by James Clerk Maxwell in 1873. Electromagnetic field takes electro-magnetic phenomenons as a expansion of formula originated in Maxwell equations. Since this is based on expansion of formula, it is hard to understand for many students not only middle school and high school students learning it at the first time but also college students studying physics as a elementary class and even majors in electromagnetic field. The program is developed as a visual aid to cope with these problems, and even to deal with complex problem to estimate solution using numerical method.

• Journal of the Korean Geophysical Society
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• v.6 no.3
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• pp.155-164
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• 2003

The validity and efficiency of the roll-along technique widely used in 2-D electrical resistivity survey are analyzed in case of the dipole-dipole and the Wenner-Schlumberger arrays by numerical modelling. The shallow anomalous resistivity bodies are successfully inverted both in the dipole-dipole and in the Wenner-Schlumberger arrays because the shallow data of pseudosection are not omitted by the roll-along technique. However, the deep anomalous resistivity bodies can not be well resolved due to the skip of observed data which is more significant in the Wenner-Schlumberger array having relatively poor horizontal coverage of obtaining data. Carrying out electrical survey adopting the dipole-dipole array, the skip of data is insignificant because it is unfeasible to expand the electrodes to the maximum electrode separation coefficient($n_max$) owing to low S/N ratio. In case of the Wenner-Schlumberger array, however, because it is generally feasible to expand the electrodes $n_max$ to the owing to high S/N ratio, it is highly possible that skip of data from the roll-along technique causes significant distortion of inversion results. Therefore, adopting the Wenner-Schlumberger array having deeper median depth(Edwards, 1977) than do the dipole-dipole array on condition of the same unit electrode spacing( ($a$) ) and $n_max$, it is recommended to determine $a$ based on not $n_max$but $n_prob$free from the skip of observing data and forward electrodes with keeping overlap interval 3/4 of the survey line length in order to reduce the distortion of resistivity structure and perform resistivity survey efficiently. These results are confirmed by numerical modelling.

• Journal of the Korean Geophysical Society
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• v.5 no.3
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• pp.233-245
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• 2002

The spectral-analysis-of-surface-waves (SASW) method is a nondestructive testing method based upon generation and detection of elastic stress waves. SASW is widely used as one of the techniques to determine stiffness profile in engineering geophysics. The essential steps involved are construction of an experimental dispersion curve from data collected in situ, and inversion of the dispersion curve to determine the stiffness profile. The main object of this study is to derive an analytical Jacobian for the inversion. If we set the subsurface to N homogeneous layer, it could save 2N times Jacobian calculation compared to numerical jacobian calculation during inversion. To reconstruct a stiffness profile, constrained damped least square method was applied for the inversion. The algorithm was tested for the numerical data and for the real asphalt and tunnel data, which were able to verify the stiffness profile. The stiffness profile reconstructed by the algorithm showed the possibility to appraise the soundness of tunnel with applications SASW.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.38 no.4
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• pp.10-21
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• 2001

This paper develops a logical simulation method for by dyversity of situations. Most existing systems, for example, games and infant tutoring systems lead users to virtual environment with unfolding situations, but are not designed to induce the change of the environment itself. In this paper, a logically simulated environment is created by defining situations and single events based on situation hierarchy structure. We elaborate the occurrence of events by classifying the causality. The occurrence or natural phenomena is dictated by physical laws and natural phenomena are expressed as the transition of the event based on event association. Specifically we define the source of the event for natural phenomena and we consider the existence of objects as a primary factor in event occurrence. The advantages of this approach include the reuse of events, that is, different events can be generated in the same flow with fresh conditions. This allows us to implement a more practical and logical environment. A drawback to this method is the difficulty in dividing a situation into events. The proposed method was implemented in the context of the change of season among natural phenomena.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.59-60
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• 2017

본 논문에서는 하이브리드 / 전기 자동차의 견인용 전동기로 널리 쓰이는 영구자석 동기 전동기를 실시간으로, 실제 전력 상황에서 모의하는 실시간 부하 모의 장치(Real-Time Emulator, RTE)의 구동에 필요한 직류단 전압의 크기에 대하여 분석한다. 운전 주파수 및 스위칭 주파수 전류 모의까지 가능한 부하 모의 장치에서, 모의 전류 및 모의 운전 속도에 따라 필요한 직류단 전압을 구하는 방법을 이론적으로 전개하고, '도요타사(社)'의 하이브리드 자동차 '프리우스'에 내장된 견인 전동기의 모의를 위해 필요한 직류단 전압의 계산에 이를 적용해본다. 실제 물리적 지표를 반영하기 위해 모의하고자 하는 전동기에 대하여 유한요소법 (Finite Element Method, FEM)을 실행하여 얻은 값들을 사용하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2000.11b
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• pp.75-80
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• 2000

본 논문은 영상복원을 역확산 과정으로 해석하여 복원된 영상을 역확산 방정식의 해로 구하는 알고리즘을 제안한다. 역확산 과정은 물리적으로 불량위치(ill-posed)과정이기 때문에, 이를 정규화 해주어야 하는데 이를 위해서 역확산 과정을 고유함수(eigenfunction)들의 전개로 나타낸 후에 고유함수들의 계수들을 조작하였다. 본 논문에서는 계수들을 조작할 때 영상이 가지고 있는 주파수 특성을 고려하여 한계주파수(cut-off frequency)를 넘은 경우에 계수들을 시간과 주파수의 감소함수로 나타내어 불량위치문제를 해결하였다. 계수를 주파수에 대한 감소함수로 나타낸 것은 영상에 저주파 성분이 많고, 고주파 성분이 영상의 형성에 끼치는 영향이 상대적으로 적다는 영상의 특성을 고려한 것이다. 이러한 감소함수를 사용하였을 때 불량위치 문제를 해결할 수 있다는 것을 증명하였고, 실험적으로 양질의 영상을 산출함을 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04d
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• pp.25-27
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• 2003

본 논문은 10GbE로의 망 전개에 따라 구현될 l0Gb 스위치에 필요한 계층2 부가서비스들 중에서 여러개의 물리적인 링크를 하나의 논리적인 링크로 집합하여 대역폭의 증가를 가져오는 링크 집합(Link Aggregation) 기술에 필요한 프레임 분배방식에 대한 것이다. 링크 집합 기술은 분배 알고리즘의 설계에 따라 스위치에서 성능의 차이를 가져오므로 링크 집합의 장정을 살리려면 종은 성능을 가지는 분배 알고리즘이 필요하다. 우선 링크 집합의 간단한 구현 방법을 살펴보고 기존에 제시된 스위치와 스위치 사이에서의 프레임 분배방식인 정적/동적 프레임 분배 방식과 우리가 새로이 제안한 패딩을 이용한 분배방식을 비교한 후, 정적/동적 프레임 분배 방식과 패딩을 이용한 분배방식을 컴퓨터 시뮬레이션을 통해 성능을 비교하였다.

• Nuclear Engineering and Technology
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• v.1 no.2
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• pp.79-85
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• 1969

Determination of a two-point boundary value problem is the key of finding the control function u(f) with the application of the fundamental idea of Minimum principle. The late development shows the discovery of the initial testate vector for the solution of a two-point value problem. As a new technique of determining the optimal control function, Newton's sequential method is examined in this paper.