• 한국BIM학회 논문집
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• 제14권1호
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• pp.1-10
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• 2024

Virtual reality is one of the key emerging technologies of the 21th century and it has been used in a variety of ways in the fields of architectural research. Virtual reality is presented as an ideal alternative for studying the interaction between space and humans because it provides a realistic spacial experience while allowing experimenters to control environmental variables at a low cost easily. It allowed us to deepen our knowledge of human spatial experience in the built environment. However, existing reviews do not include the following points: 1) previous review research has been focused on using virtual reality technology in construction and engineering, not spatial experience, 2) recently, some review researches started to study the interaction between space and humans in the built environment, however, they do not suggest specific concepts of spatial experience. The present review aims to examine the existing literature about measuring spatial experience using virtual reality in architectural design. The study conducted a systematic qualitative review that analyzes and synthesizes the evolving literature regarding design elements, methodology, and usability. The study concludes with an overall discussion and their potential for providing further directions for future research.

• Journal of Power Electronics
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• 제16권4호
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• pp.1513-1525
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• 2016

Rapid and accurate phase synchronization is critical for the reliable control of grid-tied inverters. However, the commonly used software phase-locked loop methods do not always satisfy the need for high-speed and accurate phase synchronization under severe grid imbalance conditions. To address this problem, this study develops a novel open-loop phase locking scheme based on a synchronous reference frame. The proposed scheme is characterized by remarkable response speed, high accuracy, and easy implementation. It comprises three functional cascaded blocks: fast orthogonal signal generation block, fast fundamental-frequency positive sequence component construction block, and fast phase calculation block. The developed virtual orthogonal signal generation method in the first block, which is characterized by noise immunity and high accuracy, can effectively avoid approximation errors and noise amplification in a wide range of sampling frequencies. In the second block, which is the foundation for achieving fast phase synchronization within 3 ms, the fundamental-frequency positive sequence components of unsymmetrical grid voltages can be achieved with the developed orthogonal signal construction strategy and the symmetrical component method. The real-time grid phase can be consequently obtained in the third block, which is free from self-tuning closed-loop control and thus improves the dynamic performance of the proposed scheme. The proposed scheme is adaptive to severe unsymmetrical grid voltages with sudden changes in magnitude, phase, and/or frequency. Moreover, this scheme is able to eliminate phase errors induced by harmonics and random noise. The validity and utility of the proposed scheme are verified by the experimental results.

• 한국시뮬레이션학회논문지
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• 제13권2호
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• pp.45-52
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• 2004

This paper presents a prototype visualization system of mixed reality for a VR flight simulator. The chroma key technique is used to build the mixed reality model for a VR flight simulator. The Daedeok science town can be visualized in real time according to the rider control. He can also see his own hand/foot operating the control stick/rudder as well as virtual environment projected to the blue-screen using a video-see-through HMD.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 추계종합학술대회
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• pp.791-794
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• 2005

In this paper, we describe security for a virtual heterogeneous machine. Our security architecure is based on separation of services into for distinct system support for domains, where available. We have chosen to use emergong public key technology as an interim solution to provide domain seperation. Th proposed architecture has been analysed in numerically.

• International Journal of Naval Architecture and Ocean Engineering
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• 제9권3호
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• pp.256-265
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• 2017

In this paper, an ascheme is proposed for multiuser underwater acoustic communication by using the multi-chirp rate signals. It differs from the well known TDMA (Time Division Multiple Access), FDMA (Frequency Division Multiple Access) or CDMA (Code Division Multiple Access), by assigning each users with different chirp-rate carriers instead of the time, frequency or PN code. Multi-chirp rate signals can be separated from each other by FrFT (Fractional Fourier Transform), which can be regarded as the chirp-based decomposing, and superior to the match filter in the underwater acoustic channel. VTRM (Virtual Time Reverse Mirror) is applied into the system to alleviate the ISI caused by the multipatch and make the equalization more simple. Results of computer simulations and pool experiments prove that the proposed multiuser underwater acoustic communication based on the multi-chirp rate exhibit well performance. Outfield experments carrie out in Xiamen Port show that using about 10 kHz bandwidth, four users could communicate at the same time with 425 bps with low BER and can match the UAC application.

• Structural Engineering and Mechanics
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• 제54권4호
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• pp.793-807
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• 2015

Constructing the influence lines of forces of statically indeterminate structures is a traditional issue in structural engineering and mechanics. However, the existing kinematic method for establishing these force influence lines is an indirect or mixed approach by combining the force method with the theorem of reciprocal displacements, which is yet inconsistent with the kinematic method for statically determinate structure. This paper proposes the direct kinematic method in conjunction with the load-displacement differential relation for exactly constructing influence lines of reaction and internal forces of indeterminate structures. Firstly, through applying the principle of virtual displacement, the formula for influence lines of reaction and internal forces of indeterminate structure via direct kinematic method is derived based on the released structure. Then, a computational approach with a clear concept and unified procedure as well as wide applicability based on the load-displacement differential relation of beam is suggested to achieve conveniently the closed-form expression of force influence lines, and exactly draw them. Finally, three representative examples for constructing force influence lines of statically indeterminate beams and frame illustrate the superiority of the proposed method.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2013년도 춘계학술발표대회
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• pp.507-510
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• 2013

Cloud computing is an emerging technology, which allows the user to fulfill his needs by outsourcing the resources. With the passage of time, cloud computing has become an essential part of our lives. But it still requires some sort of standardization, specially in terms of user's trust, privacy, and security related things. This study presents different types of cloud computing services and their working domains along with some key virtualization related issues that are encountered by the cloud service provider as well as the user. Those key issues, related with virtual network are discussed in this paper. This study provides a basis to work further on those issues, so that the key concerns are addressed as soon as possible and cloud computing could become standardized and more prevalent.

• 한국컴퓨터정보학회논문지
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• 제27권11호
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• pp.165-172
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• 2022

본 논문에서는 발달 장애 학생이 가상현실 콘텐츠로 직업 훈련을 수행하는 중에 콘텐츠가 부여한 과제를 이해하지 못하여 더 이상의 훈련을 진행하지 못하고 현재의 상태에 머물러 있는 상황이 발생했을 때 문제의 상태에서 스스로 벗어나서 훈련을 진행할 수 있도록 도움을 주는 행위, 즉 중재의 제공이 필요한 시점을 파악하는 방안을 연구하였다. 이를 위해, 선행 연구의 결과를 토대로 가상현실 기반의 바리스타 훈련을 수행할 수 있는 콘텐츠를 이용하여 커피 제조를 교육하는 과정에서 주어진 과제를 성공적으로 완수하기 위해 발달 장애 학생이 반드시 조작하여야 하는 바리스타 도구를 선정하고, 해당 도구와 발달 장애 학생의 왼손과 오른손과의 거리를 측정하여 통계적 분석을 통해 가설을 검증하였다. 손으로부터 관심 바리스타 도구 및 인접 도구들까지의 누적거리가 다른 바리스타 도구까지의 누적거리보다 상대적으로 긴 것으로 분석된 연구 대상자는 관심 바리스타 도구를 사용하고 있지 않을 확률이 크므로 해당 과제를 제대로 수행하고 있지 않다고 인식하고 중재를 제공할 시점이라고 판단할 수 있기 때문이다. 검증 결과, 왼손의 경우는 학생들의 훈련 수행의 성공 또는 실패 여부와 손과 바리스타 도구와의 거리간의 관계는 통계적으로 유의미하지 않은 것으로 분석되었으나, 오른손의 경우는 유의미하였다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2018년도 추계학술대회
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• pp.213-216
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• 2018

인공지능과 음성인식을 기반으로 한 스마트 디바이스의 장점이 부각되면서, 가상 비서(Virtual Assistant)가 인기를 끌고 있다. 가상 비서는 스마트 스피커를 통해 사용자 경험을 제공하며, 일반 소비자들이 가장 사용하기 쉬운 IoT 디바이스로 평가받고 있다. 본 연구는 주요 가상 비서브랜드의 음성인식 플랫폼과 디바이스에 대한 사람들의 인식에 차이가 있는지 살펴보고자 한다. 이를 위해, 트위터에서 가상비서 서비스를 하는 세 기업의 총 6가지 키워드를 포함한 트윗을 수집했다. 수집한 데이터는 의미 연결망 분석 기법(Semantic network analysis)을 적용해 키워드에 대한 사람들의 인식을 분석했다. 추가로 LIWC 감성분석을 통해 사람들의 긍정/부정적 반응을 분석했다. 분석 결과 사람들은 각 키워드에 대한 반응이 다른 것으로 나타났다. 주로 Virtual Assistant가 제공하는 기능과 서비스에 대한 기대와 사용성에 대한 내용이었다. 또한 대부분의 키워드에 긍정적 반응을 보였다.

• 한국과학교육학회지
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• 제21권4호
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• pp.725-737
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• 2001

Virtual reality technology is very useful for the 21C science education, and is able to contribute to the development of new teaching and learning methods in science education. One of these computer-based technologies, virtual reality, is possible to use in many directions. It is a new communication medium that is receiving a lot of attention, and is usually identified by a collection of technological hardware. Virtual reality is defined as a highly interactive, computer-based, multimedia environment in which the user becomes the participant, with the computer in a virtual real world. A key feature of virtual reality is real-time interactivity, in that the computer is able to detect user inputs and instantaneously modify the virtual world. It is being used in a wide variety of fields including physics, chemistry, human biology, biomedical sciences, military, architecture, industry and the entertainment. In classroom, using science educational program developed by virtual reality technology can increase the interests of students, promote understanding of basic science concepts, help laboratory skills, and encourage creative learning for them.