• 산업공학
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• 제12권2호
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• pp.193-204
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• 1999

Development of high technology especially in telecommunication and precise weapon systems will impact the future battle field environment. So it is not difficult to anticipate the environment of military command and control system will be changed rapidly. Considering these future battle field environment, military needs automated C4I (Command, Control, Communication, Computer and Intelligence) system, namely real time decision support system which is combined high technologies. Most of advanced countries have been studied and developed these kinds of systems and already applied these systems in real military operations. In order to take a military initiative in Korea peninsula it is essential to catch up with this trend and procure C4I system. The purpose of this research is to present the method and the direction of optimal C4I system development model. First we survey the related theory about C4I systems. Second we present the conceptual framework for C4I system concept development. Third we model the system using Timed Petri-Net and perform simulation. Finally we analyze the through-put time and suggest alternatives. If we model using the real organization structure, operational tasks and various situations then optimal C4I system would be developed.

• 한국자동차공학회논문집
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• 제3권1호
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• pp.33-44
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• 1995

As the occupant safety receives more attention from automobile industries. protection systems have been developed quite well. Developed protection systems must be evaluated through real tests in crash environment Since the real tests are extremely expensive. computer simulations are replaced for some prediction of the real test In the computer simulation. it is very crucial to express the real environment precisely in the modeling precess. The energy absorbing(EA) steering system has a very important rote in vehicle crashes because the occupant can hit the system directly. In this study. the EA steering system is modeled precisely. analyzed for the safely and designed by an optimization technology. First. the EA steering system is disassembled by parts and modeled by segments and joints. The segments are modeled by rigid bodies in motion and they have resistances in contact. Spring-damper elements and force-deflection curves are utilized to represent the joints. The body block test is cal lied out to validate. the modeling. When the test results are not enough for the detailed modeling. the differences between tests and simulations are minimized to calculate unknown parameters using optimization. The established model is applied to a crash simulation of a full-car model and tuned again. After the modeling is finished. components of the steering system are designed by an optimization algorithm. In the optimization process. the compound injury of a driver is defined and minimized to determine the chracteristics of the components. The second. order approximation algorithm has been adopted for the optimization.

• 대한화학회지
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• 제43권4호
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• pp.469-474
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• 1999

본 연구에서는 Randomwalk 이론을 이용하여 동영상 프로그램을 개발하였다. 보통 화학 교과는 원자, 분자와 같은 입자의 행동을 이해하는데 어려움이 많아 이에 관한 학생들의 오개념이 많이 나타나고 있다. Randomwalk 이론을 도입한 동영상으로 분자 운동을 표현한 본 프로그램은 실제 분자 운동의 과정을 제대로 이해하는데 도움을 줄 것이다. 본 연구에서는 특히 JAVA 언어를 사용하여 Web 상에 프로그램을 구현함으로써 누구나 쉽게 이용할 수 있게 하였다. 이들 프로그램은 두가지의 프로그램으로 짜여져 있다. 하나는'Diffusion' 프로그램이며, 입자의 확산 과정을 실제와 같이 동영상으로 구현되도록 하였다. 또 다른 하나는 'Randomwalk' 프로그램으로 입자의 운동 과정에 대한 궤적을 표현함으로써 분자 운동에 대한 분명한 이해를 가능하게 하였다.

• 전산구조공학
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• 제10권4호
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• pp.143-154
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• 1997

본 연구에서는 지하암반구조물의 구조해석시 불연속암반체의 물성변이를 고려할 수 있는 확률론적 해석기법을 개발하였다. 수치해석적 접근은 몬테칼로모사기법의 단점을 보완한 LHS기법을 사용하였고, 불연속면의 영향은 단층, 벽개 등과 같이 불연속성이 뚜렷한 지역에서 적용성이 높은 절리유한요소모델을 사용하였다. 재료특성에 대한 확률변수는 불연속면의 수직강성과 전단강성을 다확률변수로 사용하였으며, 이들은 확률공간에서 정규분포를 갖는 경우에 대하여 고려하였다. 본 연구에서 개발된 수치해석프로그램은 검증예제를 통하여 타당성을 확인하였으며, 가상의 불연속면군이 존재하는 지하원형공동에 대한 해석을 통하여 프로그램의 적용성을 확인하였다.

• Preventive Nutrition and Food Science
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• 제20권1호
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• pp.60-66
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• 2015

The aim of this study was to determine the heat-penetration characteristics using stationary and rotary retorts to manufacture Kimchi soup. Both heat-penetration tests and computer simulation based on mathematical modeling were performed. The sterility was measured at five different positions in the pouch. The results revealed only a small deviation of $F_0$ among the different positions, and the rate of heat transfer was increased by rotation of the retort. The thermal processing of retort-pouched Kimchi soup was analyzed mathematically using a finite-element model, and optimum models for predicting the time course of the temperature and $F_0$ were developed. The mathematical models could accurately predict the actual heat penetration of retort-pouched Kimchi soup. The average deviation of the temperature between the experimental and mathematical predicted model was 2.46% ($R^2=0.975$). The changes in nodal temperature and $F_0$ caused by microbial inactivation in the finite-element model predicted using the NISA program were very similar to that of the experimental data of for the retorted Kimchi soup during sterilization with rotary retorts. The correlation coefficient between the simulation using the NISA program and the experimental data was very high, at 99%.

• 대한교통학회지
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• 제26권6호
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• pp.93-101
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• 2008

무선 통신 장비의 빠른 확산과 함께 교통 분야에도 새로운 시도가 이루어지고 있다. 무선 통신 기술의 하나인 애드혹 네트워크를 차량에 적용한 Vehicular Ad hoc Networks (VANETs)은 주행중인 차량간의 통신을 가능하게 하여 교통 안전, 혼잡 정보 등의 교통 정보 전달에 활용이 검토되고 있다. 하지만, VANET 기술은 아직 연구 수준이고, 실험에 있어 시간과 비용의 한계 때문에 컴퓨터 모의실험에 의존하고 있다. VANET 기반은 교통과 통신의 통합된 환경임에도 불구하고, 이전 연구에서는 한 분야만의 환경을 고려하였거나, 현실적인 통합 환경을 이루지 못하였다. 본 연구에서는 기존 실험의 한계를 극복하기 위하여, 실제 VANET 기반 교통 시스템에서 발생하는 차량의 움직임과 무선 통신 특성을 표현하기 위한 미시적 교통 모의실험 모형과 통신 모의실험 모형을 시 공간적으로 동기화한 모의실험 환경을 설계하였다. 사례 연구로, 실제 도로 및 교통 수요 자료를 사용하여 설계된 모의실험 환경을 적용하였고, 교통 특성과 통신 특성을 잘 반영하는 결과를 얻었다. 향후, 본 연구에서 설계된 모의실험 환경은 VANET 기반 교통 시스템의 다양한 설계에 활용될 것으로 기대된다.

• 대한안전경영과학회지
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• 제11권3호
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• pp.19-26
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• 2009

It is becoming more and more important to develop safety-critical systems with special attention. Examples of the safety-critical systems include the mass transportation systems such as high speed trains, airplanes, ships and so forth. Safety critical issues can also exist in the development of atomic power plants that are attracting a great deal of attention recently as oil prices are sky-rocketing. Note that the safety-critical systems are in general large-scale and very complex for which case the effects of adopting the systems engineering (SE) approach has been quite phenomenal. Furthermore, safety-critical requirements should necessarily be realized in the design phase and be effectively maintained thereafter. In light of these comments, we have considered our approach to developing safety-critical systems to be based on the method combining the systems engineering and safety management processes. To do so, we have developed a design environment by constructing a whole life cycle model in two steps. In the first step, the integrated process model was developed by integrating the SE (ISO/IEC 15283) and systems safety (e.g., hazard analysis) activities and implemented in a computer-aided SE tool environment. The model was represented by three hierarchical levels: the life-cycle level, the process level, and the activity level. As a result, one can see from the model when and how the required SE and safety processes have to be carried out concurrently and iterately. Finally, the design environment was verified by the computer simulation.

• 한국실내디자인학회논문집
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• 제15권5호
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• pp.306-313
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• 2006

Digital simulation which was introduced to the architectural field due to the rapid growth of computer graphics, gave birth to a new type of contents called 'virtual reality', led by the interaction with the users and real time processing. The public attention is drawn to the virtual reality's potential as a next generational space simulation it, having the unique characteristics of 'simulation', 'interactivity', 'tole-presence', and 'immersion', is capable of taking a virtual tour of a space with a size equivalent to that of a real space, as well as proceeding with the design progress. Nonetheless, many problems impeding CPU's real time processing of an excessively loaded architectural model data have been pinpointed over the time. Yet such GPU based game engines as 'DirectX' and 'OpenGL', developed to deal with these impediments, have not been easily applied to the architectural simulation in the design process, due to the high license cost and the specific technical requirements for the system. The virtual reality has been developed and distributed centering around the gaming field, and game developers recently show a greater tendency to include level editors in the package for the expandability purpose. Thus, we plan to propose architecture simulation which utilizes level editors in this study. In addition, the compatibility of the game engine based level editors of Quake and Unreal which form the standards for the open source FPS games, based on VRML, the standard format for the virtual reality, was compared and analyzed. Taking the example of Villa Savoye of Le Corbusier, its application possibility as an architecture simulation was assessed, by measuring the extent to which the performance of such characteristic features of the virtual reality as interactivity, immersion, and tele-presence, was improved.

• Journal of Biosystems Engineering
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• 제21권3호
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• pp.293-305
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• 1996

Effects on the tractor vibrations of tread, wheelbase and axle load distribution were analyzed by using mathematical models of tractor and random road surface. A 4 degrees of freedom tractor model was developed to predict the bounce, pitch and roll motions of tractor. The front axle which is constrained to roll with respect to tractor body was also included in the model. A random road profile was generated and used as an excitation input to the tractor. Output vibrations of the model were predicted and analyzed by a computer simulation method. In general, longer tread tends to reduce rolling and longer wheelbase does bouncing and pitching motions. Tractor vibrations were minimum when the ratio of front to rear axle loads was in the range of 30:70-35:65. Sensitivity analysis showed that rolling and pitching motions most sensitively varied with changes in tread and wheelbase while bouncing motion did with the location of mass center.

• 한국시뮬레이션학회:학술대회논문집
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• 한국시뮬레이션학회 2003년도 추계학술대회 및 정기총회
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• pp.3-10
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• 2003

Developments in science and technology based on computer technology influenced military fields and created up-to-date weapons and equipment, and as a result, which is changing the war accomplishing methods of the future warfare. Due to these changes in the war accomplishing methods, the army command centers are requested to make changes in their decision-making process. In other words, they need to apply more scientific methods rather than just build a scheme by the mere analysis of commanders and the staffs as in the past. Consequently, we propose a model, Vision 21 we developed as a war game model for division-size unit analysis use, in the COA development process, which is the most important part in establishing the OPLAN for mission accomplishment. Vision 21, with a comparative analysis of the other COA built in the COA development process, can be applied to making the best COA. Model employment concept can let us choose the best COA, operating war games on condition that the COA of the opposite forces is fixed and ours sequentially opposed against, and with a comparative analysis also. Moreover, if the time available is limited, before establishing several courses, we can apply the COA to the process for making the best decision, analysing in stages or by main phases and not establishing several courses for a special purpose.