• Journal of the HCI Society of Korea
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• v.1 no.1
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• pp.9-20
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• 2006

This paper describes a framework for multimodal object manipulation in virtual environments. The gist of the proposed framework is the semantic integration of multimodal input using spatial ontology and user context to integrate the interpretation results from the inputs into a single one. The spatial ontology, describing the spatial relationships between objects, is used together with the current user context to solve ambiguities coming from the user's commands. These commands are used to reposition the objects in the virtual environments. We discuss how the spatial ontology is defined and used to assist the user to perform object placements in the virtual environment as it will be in the real world.

• Journal of KIBIM
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• v.9 no.4
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• pp.1-9
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• 2019

Visualized information platforms through building information modeling (BIM) such as virtual reality (VR) and augmented reality (AR) improves the efficiency of architectural information exchange. Despite that, less effort has been directed to evaluate the effectiveness of different BIM visualization platforms for architectural design review. This study fills these gaps and compares three BIM visualization tools for reviewing diverse architectural review factors and technology acceptance degree. Three main BIM visualization tools, which are desktop-based, virtual reality-based and augmented reality-based, were employed and different architectural review factors and user's technology acceptance degree was measured. As a result, VR and AR environment showed better visual presentation than desktop environment during design review. In terms of the technology acceptance level, VR and AR environments have received higher ratings compared to desktop environments. The detailed findings provide guidelines for participants and researchers involved in design review process to selectively adopt VR and AR system to various architectural design review components.

• International Journal of Advanced Culture Technology
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• v.10 no.4
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• pp.518-528
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• 2022

Virtual Reality (VR) has been widely used in various applications to generate realistic virtual environments. A sense of immersion can be increased by providing additional stimuli such as tactile sensation to VR contents. However, it is still challenging to provide a realistic feel for the wind blowing over the whole body by smoothly controlling the airflow. To address this issue, we employ a household electric fan as a wind generating device to provide users with wind experience in VR environments. The wind generating device targets the whole body to mimic the wind we feel outside in our daily life. To do so, we present a low-cost method to smoothly control household fan speed using an Arduino microcontroller. Here, we use the Sinusoidal Pulse Width Modulation (SPWM) technique to generate the sinusoidal voltage required to drive the fan motor. Our experimental results show how Variable Voltage Variable Frequency (VVVF) is implemented at a low cost using our method for household fan speed control. The results can be applied to various VR applications to enhance the sense of immersion by providing users with realistic wind.

• Korean Journal of Computational Design and Engineering
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• v.21 no.1
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• pp.20-30
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• 2016

Recently immersive virtual reality (VR) becomes popular due to the advanced development of I/O interfaces and related SWs for effectively constructing VR environments. In particular, natural and intuitive manipulation of 3D virtual objects is still considered as one of the most important user interaction issues. This paper presents a comparative study on the manipulation and interaction of 3D virtual objects using different interfaces and interactions in three VR environments. The comparative study includes both quantitative and qualitative aspects. Three different experimental setups are 1) typical desktop-based VR using mouse and keyboard, 2) hand gesture-supported desktop VR using a Leap Motion sensor, and 3) immersive VR by wearing an HMD with hand gesture interaction using a Leap Motion sensor. In the desktop VR with hand gestures, the Leap Motion sensor is put on the desk. On the other hand, in the immersive VR, the sensor is mounted on the HMD so that the user can manipulate virtual objects in the front of the HMD. For the quantitative analysis, a task completion time and success rate were measured. Experimental tasks require complex 3D transformation such as simultaneous 3D translation and 3D rotation. For the qualitative analysis, various factors relating to user experience such as ease of use, natural interaction, and stressfulness were evaluated. The qualitative and quantitative analyses show that the immersive VR with the natural hand gesture provides more intuitive and natural interactions, supports fast and effective performance on task completion, but causes stressful condition.

• Journal of KIISE:Computer Systems and Theory
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• v.28 no.12
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• pp.642-652
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• 2001

Recently, the advent of World-Wide-Web(WWW) and the explosive popularity of the Internet gave birth to collaborative applications which were enabled by computers and networks as their primary media. The progress of 3D computer graphics enabled collaborative application with 3D virtual environments or distributed virtual environments. In this paper, we explain our implementation of the Share collaboration engine which is for collaboration applications based on a distributed virtual environment. We introduce Virtual Architectural Engineering 2000 (VAE2000) that is our pilot application implemented with the Share collaboration engine. The Share collaboration engine proposes a new Share network architecture for management of participants, and it provides some synchronization methods for 3D objects in virtual collaboration. VAE2000 is an experimental application that tries to prevent wastes of human, material and time resources in networked virtual collaboration.

• The Journal of Korean Association of Computer Education
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• v.18 no.2
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• pp.83-90
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• 2015

In an virtualization environment, several virtual machines use physical resources together. If a specific virtual machine uses to much of the computing resources, other machines may not be working properly. There are various method to solve this problem. Most representative study is to migrate a specified virtual machines to a different server, a target server. In this study, server load can be transferred to a target server by the remigrate of the load imposed on virtual machine. It is still problematic that virtual machine has to remigrate to a different server. This thesis has proposed the algorithm determining the remigration targets by applying dynamic thresholds to solve those problems. The migration algorithm applies dynamic thresholds according to the following criteria. Firstly, the usage of CPU, network and memory; secondly, decide the set of artificial machine and the target server based on the resources surpassed thresholds; thirdly, determine artificial machines based on the resource usage in the target server.

• Journal of the Korea Computer Graphics Society
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• v.16 no.3
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• pp.11-19
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• 2010

This paper describes how to define and implement the schema for 3D virtual objects with physical units so that the objects can be compared in virtual environments based on physical properties, such as length, according to the specified units. We define physical units for virtual objects using the International System of Units and based on the X3D (Extensible 3D) specification. The schema must be defined with validation so that it does not violate the original X3D data structure. In this paper, we have extended the original X3D schema with a physical unit specification, and demonstrate the difference between units-specified and non-units-specified 3D scenes using an X3D browser that we developed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.649-654
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• 2019

Stable haptic interaction with virtual environments is essential not only for the safety of the user but also for improving the immersion of the user. If the coefficient of a virtual spring is increased, the system becomes unstable. Therefore, the coefficient of the virtual spring is limited. The haptic system with the high-frequency zero-order-hold (HF-ZOH) is proposed to enhance the stability margin of a virtual spring. In this paper, the relationship among the sampling period of HF-ZOH, the coefficient of the physical damper, and the maximum stable margin of the virtual spring is analyzed. The lager the coefficient of the physical damper is, the shorter the sampling period of the HF-ZOH is, the larger the stable region of the virtual spring becomes. If the ratio N is larger than 40, the stable region of the proposed method is about three times to eight times that of the previous method, according to the coefficient of the physical damper. Hence the method enables to improve the user's realism in virtual environments.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.575-578
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• 2002

With the paradigm shifting from the principal of manufacturing efficiency to business globalization and rapid adaptation to its environments, more and more enterprises are being virtually organized as manufacturing network of different units in web. The formation of these enterprise called as Virtual Enterprise(VE) is becoming a growing trend as enterprises concentrating on core competence and economic benefit. This paper proposes the cooperation methodology for VEs which can be organized by the selection of manufacturing partners, and managed by the information flow infrastructure.

• Journal of the Korea Institute of Military Science and Technology
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• v.26 no.1
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• pp.91-101
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• 2023

Modeling and Simulation(M&S) technology has been widely used to solve constraints such as time, space, safety, and cost when we implement the same development and test environments as real warfare environments to develop, test, and evaluate weapon systems for the last several decades. The integration and test environments employed for development and test & evaluation are required to provide Live Virtual Construction(LVC) simulation environments for carrying out requirement analysis, design, integration, test and verification. Additionally, they are needed to provide computing environments which are possible to reconfigure computing resources and software components easily according to test configuration changes, and to run legacy software components independently on specific hardware and software environments. In this paper, an Integration Test and Simulation for Engagement Control(ITSEC) bed using a bare-metal virtualization mechanism is proposed to meet the above test and simulation requirements, and it is applied and implemented for an air missile defense system. The engagement simulation experiment results conducted on air and missile defense environments demonstrate that the proposed bed is a sufficiently cost-effective and feasible solution to reconfigure and expand application software and computing resources in accordance with various integration and test environments.