• 한국컴퓨터정보학회논문지
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• 제24권8호
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• pp.137-142
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• 2019

This paper proposed bitmap based spatial data transmission scheme in need of rapid transmission through network in mobile environment that use and creation of data are frequently happen. Former researches that used clustering algorithms, focused on providing service using spatial data can cause delay since it doesn't consider the transmission speed. This paper guaranteed rapid service for user by convert spatial data to bit, leads to more transmission of bit of MTU, the maximum transmission unit. In the experiment, we compared arithmetically default data composed of 16 byte and spatial data converted to bitmap and for simulation, we created virtual data and compared its network transmission speed and conversion time. Virtual data created as standard normal distribution and skewed distribution to compare difference of reading time. The experiment showed that converted bitmap and network transmission are 2.5 and 8 times faster for each.

• 대한건축학회논문집:계획계
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• 제35권12호
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• pp.13-20
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• 2019

The purpose of this study was to investigate the effects of visual properties on the human movement behavior experimentally and empirically using spatial analysis technique based on ecological perception theory. For the survey of choosing behaviors of heading direction in built environments, the experiment was conducted in which the subjects were made to choose moving directions in some spaces using the virtual environment simulation tool, and then comparative analysis was conducted on the interrelation between the experiment results and various visual properties in existing spatial analysis techniques based on ecological perception theory. As a result, the occlusivity of the isovist theory was found to be the most significant index in the human choice of heading direction, and the longest radial also showed somewhat significant effect on it.

• 한국정보과학회논문지:시스템및이론
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• 제30권11호
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• pp.675-690
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• 2003

시스템과 네트워크 클라이언트의 제한된 리소스를 이용하여 다수의 사용자가 참여 가능하고 사용자의 QoS를 만족시키는 분산 가상 시스템에 대한 연구가 활발히 진행되고 있다. 이러한 분산 가상 시스템을 구현하기 위해서는 사용자의 증가에 따른 네트워크 트래픽 증가 문제, 네트워크 지연으로 발생하는 클라이언트간의 동기화 문제, 가상 환경 렌더링에 따른 시스템 부하 등의 문제를 해결해야 한다. 본 논문에서는 3인칭 시점의 가상 댄싱 공간을 구성하여 아바타간의 상호 작용을 지원하고 사용자가 느끼는 화질에 따라 네트워크를 통해 전송되는 데이타의 양을 달리하는 계층적 QoS 모델을 제안한다. 계층적 QoS 모델은 화면을 보는 사용자의 시점에 기반하여 가상 댄싱 공간에서 보여지는 아바타의 화질을 조절하는 Visual QoS와 아바타의 영향 범위 및 아바타간의 거리에 의해 사용자에게 들리는 소리의 크기를 조절하는 Audio QoS로 구성된다. 이 기법의 효율성을 검증하고자 Sun사의 JMF와 Java3D를 이용하여 사용자의 실영상과 3D CG 아바타가 참여하는 가상 댄싱 공간을 구현한다. 본 논문에서 제안한 계층적 QoS 모델이 다수의 아바타가 참여하고 아바타의 밀집도가 높은 가상 댄싱 공간을 효과적으로 지원할 수 있다는 것을 TIE 시스템의 성능 실험과 시뮬레이션을 통해 확인한다.

• 산업경영시스템학회지
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• 제39권1호
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• pp.31-36
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• 2016

Recently, Live-Virtual-Constructive (L-V-C) integrate training system has proposed as a solution for the problems such as limitation of training areas, increase of mission complexity, rise in oil prices. In order to integrate each training system into the one effectively, we should solve the issue about stress of pilots by the environmental differences between Live and Virtual simulation which could be occurred when each system is connected together. Although it was already examined in previous study that the psychological effects on pilots was occurred by the environmental differences between actual and simulated flights, the study did not include what the causal factors affecting psychological effects are. The aim of this study is to examine which environmental factors that cause pilots' psychological effects. This study analyzed the biochemical stress hormone, cortisol to measure the pilots' psychological effects and cortisol was measured using Enzyme-linked immunoassay (EIA). A total of 40 pilots participated in the experiment to compare the differences in pilots' cortisol response among live simulation, virtual simulation, and the virtual simulation applying three environmental factors (gravity force, noise, and equipment) respectively. As a result, there were significant differences in cortisol level when applied the gravity force and equipment factors to the virtual simulation, while there was no significant difference in the case of the noise factor. The results from this study can be used as a basis for the future research on how to make L-V system by providing minimum linkage errors and design the virtual simulator that can reduce the differences in the pilots' psychological effects.

• 공학교육연구
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• 제5권1호
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• pp.19-26
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• 2002

본 논문에서는 학습자와 교수자간의 상호작용을 극대화하여 웹 상에서 효과적인 학습이 일어날 수 있도록 하는 기초전기회로 가상실험실을 자바 애플릿을 이용하여 구현하였다. 제안된 가상 실험실은 크게 실험원리학습실, 모의실험학습실, 자바가상실험학습실 및 가상실험실 관리 및 평가시스템으로 구성되어 있어 학습자로 하여금 흥미를 유발하여 전기회로실험을 간단한 마우스 조작만으로 수행하여 예비실험 결과를 데이터베이스에 저장하여 PHP를 이용하여 예비보고서 형태로 작성하여 학습자로 하여금 출력하여 프린트할 수 있도록 하였다. 본 논문에서 구현된 효율적인 기초전기회로 가상실험실은 수많은 방법중의 하나로써 향후 많은 수정과 보완이 이루어지리라 기대하며 기존의 교육시스템에서 발생되는 문제를 상당부분 보완할 수 있을 것으로 생각된다.

• 한국시뮬레이션학회논문지
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• 제30권1호
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• pp.139-152
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• 2021

시뮬레이션을 통하여 경험하기 어려운 사건을 가상적으로 체험할 수도 있으며, 분석을 수행할 수도 있다. 국방시뮬레이션 분야에서 이런 체험을 기반으로 Virtual 시뮬레이션이 연구 개발되고 있으며, 분석을 위하여 Constructive 시뮬레이션이 연구 개발되고 있다. 이런 시뮬레이션을 연동하여, VC(Virtual-Constructive) 시뮬레이션 환경을 구성할 수 있고, VC 시뮬레이션 환경은 전투 환경의 가상적인 경험과 교전개체의 지능적인 전술을 동시에 시험할 수 있는 환경이다. 또한, 최근의 인공지능 연구를 위해, 사람의 행동을 학습하는 이미테이션 학습 혹은 역강화학습 분야는 VC 환경에서 수집된 인간 행동 데이터를 필요로 한다. 제시된 연구는 공중전 분야에 VC 시뮬레이션 환경의 사례를 보여주며, 이를 통해 수집된 인간 행동 데이터의 특징을 분석하고 있다. 본 논문을 통하여, 공중전 분야 VC 시뮬레이션 환경이 어떻게 구축될 수 있으며, 인공지능 학습을 위하여 어떻게 활용될 수 있는지 보여준다.

• 전력전자학회논문지
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• 제4권5호
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• pp.455-461
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• 1999

본 논문에서는 가상환경 내의 물체로부터 역감을 얻을 수 있는 3자유도 힘 반향 장치를 제안한다. 이 시스템은 디바이스와 가상환경의 모델과 힘 반향 렌더링 알고리즘 등으로 구성되었다. 평행링크 메커니즘과 와이어에 의한 토크전달 그리고 임피던스 제어가 가능한 제어기를 사용해 3자유도 힘 반향 역감장치(Force-reflecting device)를 설계하였다. 위치 함수만으로 계산되는 힘 반향동작은 God-Object 알고리즘을 사용했다. 3차원 가상물체와 시험 제작한 역감장치(Force-reflecting device)를 인터페이스 실험을 통해 3차원 가상물체와 접촉과 비접촉 그리고 푸쉬 버튼을 만지는 느낌을 검출하였다.

• 한국자동차공학회논문집
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• 제23권5호
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• pp.486-493
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• 2015

In this paper, a battery model for electric vehicle virtual platform was developed. A battery model consisted of a battery cell model and battery thermal management system. A battery cell model was developed based on Randles equivalent circuit model. Circuit parameters in the form of 3D map data was obtained by charge-discharge experiment of Li-Polymer battery in various temperature condition. The developed battery cell model was experimentally verified by comparing voltages. Thermal management system model was also developed using heat generator, heat transfer and convection model, and cooling fan. For verification of the developed battery model in vehicle level, the integrated battery model was applied in to EV(electric vehicle) virtual platform, and virtual driving simulation using UDDS velocity profile was conducted. The accuracy of the developed battery model has been verified by comparing the simulation results from EV platform with the experimental data.

• 한국IT서비스학회지
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• 제19권3호
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• pp.75-87
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• 2020

This study empirically investigates the design factors that could engender positive impacts on consumers' user experiences with respect to trust, attitude, and intent to purchase a product promoted in the virtual reality (VR) e-commerce environment. Guided by previous literature, we specifically test the role of schema congruity due to the design of the space and virtual agent on trust, attitude, and purchase intention in the context of VR e-commerce. To test the effect of the congruency between user's schema and virtual environment design on user intentions, a 2 × 2 mixed ANOVA design experiment was conducted with place creativity (Low vs. High) as a within factor and workplace attire (Casual vs. Formal) as a between factor. The result showed support for the effect of schema congruity on trust, in that interaction of the two factors were found. Significant positive relationship between trust, attitude, and purchase intention was found. Further implications are discussed based on results.

• Journal of Radiation Protection and Research
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• 제45권1호
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• pp.35-44
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• 2020

Background: Cadmium zinc telluride (CZT) is a promising material because of a high detection efficiency, good energy resolution, and operability at room temperature. However, the cost of CZT dramatically increases as its size increases. In this study, to achieve a large effective volume with relatively low cost, an array structure comprised of individual virtual Frisch-grid CZT detectors was proposed. Materials and Methods: The prototype consisted of 2 × 2 CZTs, a holder, anode and cathode printed circuit boards (PCBs), and an application-specific integrated circuit (ASIC). CZTs were used and the non-contacting shielding electrode method was applied for virtual Frisch-grid effect. An ASIC was used, and the holder and the PCBs were fabricated. In the current system, because the CZTs formed a common cathode, a total of 5 channels were assigned for data processing. Results and Discussion: An experiment using ¹³⁷Cs at room temperature was conducted for 10 minutes. Energy and timing information was acquired and the depth of interaction was calculated by the timing difference between the signals of both electrodes. Based on obtained three-dimensional position information, the energy correction was carried out, and as a result the energy spectra showed the improvements. In addition, a Compton image was reconstructed using the iterative method. Conclusion: The virtual Frisch-grid CZT detector based on the array structure was developed and the energy spectra and the Compton image were successfully acquired.