• 한국정보과학회논문지:시스템및이론
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• 제33권1_2호
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• pp.119-127
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• 2006

가상환경에서의 실시간 캐릭터 애니메이션은 컴퓨터 게임 및 가상현실 분야에서 중요한 문제이다. 최근에는 캐릭터 애니메이션의 사실성을 높이기 위해 대규모 동작 캡쳐 데이타를 활용하고 있다. 그러나 거대하고 복잡한 가상환경을 만들기 위해서는 현실 환경에서 동작을 캡쳐하고 이를 넓은 가상환경에 적용해야하는 어려움이 따른다. 본 논문에서는 애니메이션 캐릭터가 몇 가지 빌딩 블록(building block)들로 건설된 넓은 가상공간에서 자유롭게 활동하게 하는 새로운 방법을 제안한다. 빌딩 블록들은 반복적인 형태로 배열되어 더 큰 환경을 생성할 수 있다. 이러한 각각의 블록들을 모션 패치(motion patch)라고 부른다. 모션 패치는 해당 블록 내부에서 캐릭터가 수행할 수 있는 동작들에 대한 정보를 가지고 있다. 본 논문은 다수의 캐릭터가 방대하고 복잡한 가상환경 속에서 실시간으로 애니메이션되고 제어되는 예제들을 통해 이 논문에서 제시하는 방법이 다양한 목적에 유용하게 사용될 수 있음을 보인다.

• 로봇학회논문지
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• 제3권2호
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• pp.137-145
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• 2008

We present the initial results of on-going research for building a novel Mobile Haptic Interface (MHI) that can provide an unlimited haptic workspace in large immersive virtual environments. When a user explores a large virtual environment, the MHI can sense the position and orientation of the user, place itself to an appropriate configuration, and deliver force feedback, thereby enabling a virtually limitless workspace. Our MHI (PoMHI v0.5) features with omnidirectional mobility, a collision-free motion planning algorithm, and force feedback for general environment models. We also provide experimental results that show the fidelity of our mobile haptic interface.

• Educational Technology International
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• 제22권1호
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• pp.1-21
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• 2021

This study examined the effects of egocentric distance and screen size on learners' perceived virtual presence in a virtual reality environment with a large-screen display. Sixty-four undergraduate students participated in the study, which used a 3×2 randomized-block factorial design with repeated measures. Two independent variables were included: 1) egocentric distance, or the physical distance between the viewer's position and a screen display, and 2) screen size, or different screen heights with fixed width. Learners' perceived virtual presence, comprising involvement, spatial presence, and realness, was the dependent variable. Results showed that egocentric distance had significant effects on virtual presence, while screen size had none. A detailed discussion and implications are provided.

• 대한인간공학회지
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• 제23권1호
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• pp.23-38
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• 2004

This study examines different types of navigation aids when a navigator performs target search tasks in Virtual Environments. The factors manipulated in this study include target information (None/Landmark). navigational difficulty (Easy/Difficult). and map types (None/2D Map/3D Map). Navigation performance was measured by using task completion time and the number of target locations that was remembered by the navigator. In addition, user satisfaction on the navigation aids was also measured by using a 7-point Likert's scale. The results showed that the user satisfaction on the landmark was high when the 3D Map was provided. The task completion time shortened when navigational difficulty was set at "easy." The number of remembered target locations was large when there was no landmark. It was also large with an easy navigation task. or a map (20 or 3D) provided. Guidelines for selecting navigation aids were proposed based on the results.

• Journal of Information Processing Systems
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• 제9권3호
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• pp.489-498
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• 2013

In this paper, we propose a common simulation model that can be reused for different performance evaluations of networked virtual environments. To this end, we analyzed the common features of NVEs, in which multiple regions compose a shared space, and where a user has his/her own interest area. Communication architecture can be client-server or peer-server models. In usual simulations, users move around the world while the number of users varies with the system. Our model provides various simulation parameters to customize the region configuration and user movement pattern. Furthermore, our model introduces a way to mimic a lot of users in a minimal experiment environment. The proposed model is integrated with our network framework, which supports various scalability approaches. We specifically applied our model to the interest management and load distribution schemes to evaluate communication overhead. With the proposed simulation model, a new simulation can be easily designed in a large-scale environment.

• 한국멀티미디어학회논문지
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• 제12권12호
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• pp.1819-1826
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• 2009

To enhance the automatic performance of existing predicting and planning algorithms that require a predefined probability of the states' transition, this paper proposes a multiple sequence generation system. When interacting with unknown environments, a virtual agent needs to decide which action or action order can result in a good state and determine the transition probability based on the current state and the action taken. We describe a sequential behavior generation method motivated from the change in the agent's state in order to help the virtual agent learn how to adapt to unknown environments. In a sequence learning process, the sensed states are grouped by a set of proposed motivation filters in order to reduce the learning computation of the large state space. In order to accomplish a goal with a high payoff, the learning agent makes a decision based on the observation of states' transitions. The proposed multiple sequence behaviors generation system increases the complexity and heightens the automatic planning of the virtual agent for interacting with the dynamic unknown environment. This model was tested in a virtual library to elucidate the process of the system.

• 한국정보과학회논문지:정보통신
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• 제27권1호
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• pp.1-11
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• 2000

최근 폭발적으로 늘어난 인터넷의 사용으로 분산 가상 환경(Distributed Virtual Environments: DVE)에 대한 연구가 활발해지고 있다. 분산 가상 환경은 같은 응용을 사용하는 사용자들의 데이타를 실시간으로 공유하게 하는 공유 인터넷 응용 환경을 제공하는 것을 목적으로 한다. 더 많은 사용자가 동시에 하나의 세션에서 사용을 할수록 공유되는 데이타는 늘어나게 되고, 이에 따라 분산 가상 환경의 사용자의 만족도를 충족시킬 수 있는 서비스 품질을 유지하는 것은 매우 어려운 일이다. 기존의 분산가상 환경에 대한 연구들은 이를 응용 수준의 동기화와 데이타 전송의 문제로서 해결하려는 경우가 많았으며 이는 매우 각각의 응용에서 발생하는 개별적 문제에 대한 해결방법의 제시라는 제한적인 접근이었다. 이에 이 논문에서는 네트워크 중심적인 접근으로 대형 분산 가상 환경의 응용을 쉽게 개발 할 수 있는 새로운 구조로서 GAIA(Giga-objects Architecture for Internet Applications)라는 구조와 이에 따른 프로토콜을 제안하고 시뮬레이션으로 이의 유용성을 증명한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권7호
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• pp.2649-2666
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• 2015

In the dynamic cloud computing environment, to ensure, under the terms of service-level agreements, the maximum efficiency of resource utilization, it is necessary to investigate the online dynamic management of virtual machine resources and their operational application systems/components. In this study, the feasibility and properties of the division of virtual machine resources on the cloud platform, using the virtual machine cluster as the management unit, are investigated. First, the definitions of virtual machine clusters are compared, and our own definitions are presented. Then, the feasibility of division using the virtual machine cluster as the management unit is described, and the isomorphism and reconfigurability of the clusters are proven. Lastly, from the perspectives of clustering and cluster segmentation, the dynamics of virtual machines are described and experimentally compared. This study aims to provide novel methods and approaches to the optimization management of virtual machine resources and the optimization configuration of the parameters of virtual machine resources and their application systems/components in large-scale cloud computing environments.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2000년도 Proceeding of CIN-KIN Joint Symposium 2000 on M.E.T. Under STCW 78/95 and SINO-KOREA MARITIME CONTACT IN MID-CENTURIES
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• pp.93-105
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• 2000

This paper describes prototype Virtual Reality Ship Simulator (VRSS) that we have recently developed next-generation training equipment based on the virtual reality (VR) technology. The inherent defects of conventional ship simulators are enormous costs and difficult system upgrade due to the system construction, such as large mock-up bridge system, wide visual presentations, In this paper, to cope with those problems, we explored VR technology that can give realistic environments in a virtual world. Then we constructed prototype VRSS system, which is, consists of PC-based human sensors, and Databases set having 3D object models and coefficients of Head Related Transfer Functions (HRTFs). 3D-WEBMASTER authoring tool was used as Virtual Reality Modeling Language (VRML). Using the VRSS system, we constructed Port an Passage Simulator for the harbor of INCHON in Korea, and Ship and Sea State Simulator for an arbitrary given sea environmental states by user. Through many simulation tests, we testified the efficiency of developed prototype VRSS by subject assessment with five participants. Then, we present results on the simulation experiments and conclude with discussion of evaluation results.

• 한국멀티미디어학회논문지
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• 제3권4호
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• pp.389-398
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• 2000

본 연구에서는 PDS시스템 -HMD와 기타 VDU-이 가상환경에서 인체에 어떠한 영향을 미치는가를 조사하였다. 연구에 관련된 실험은 HMD나 VDU를 착용하고 한시간 정도의 3차원 게임을 한 결과를 분석하였다. 정량적인 측정 및 분석 도구로는 SSQ와 RSSQ, 실험전후의 자세 테스트, 그리고 시각 테스트가 실행되었다. 실험 결과는 피 실험자간의 개인적 차이는 있지만 자세 안정성 테스트 결과와 SSQ 와 RSSQ TS 간의 관계가 크다는 것을 알 수 있었다. HMD의 SSQ, RSSQ 의 TS는 VDU의 TS 보다 1.5배 높았고, 특히 넓은 시야를 가진 MRG 3C의 TS는 SS를 일으킬 가능성이 2배나 많았다. 시뮬레이터의 통제 정도에 따른 Sickness 정도를 조사하기 위하여 수동적 환경과 능동적 환경에서 실험한 결과 PDS간 유의성은 보이지 않았으며 같은 환경의 반복적인 경험을 통하여 sickness유발 가능성이 감소할 것이라는 가정도 유의성이 크지 않았다. 방향감각 상실 증상군과 안구운동 불편 증상군의 TS가 높게 나타났으며 또한 RSSQ를 통하여 긴장/당황증상군의 TS도 높게 나타났다. 이는 가상환경에 노출시 개인적 두려움도 sickness 가능성을 유발하고 있다고 유추할 수 있었다.