• Journal of Broadcast Engineering
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• 제4권2호
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• pp.87-102
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• 1999

We propose an algorithm for augmenting a real video sequence with views of graphics ojbects without metric calibration of the video camera by representing the motion of the video camera in projective space. We define a virtual camera, through which views of graphics objects are generated. attached to the real camera by specifying image locations of the world coordinate system of the virtual world. The virtual camera is decomposed into calibration and motion components in order to make full use of graphics tools. The projective motion of the real camera recovered from image matches has a function of transferring the virtual camera and makes the virtual camera move according to the motion of the real camera. The virtual camera also follows the change of the internal parameters of the real camera. This paper shows theoretical and experimental results of our application of non-metric vision to augmented reality.

• Journal of the Korea Computer Graphics Society
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• 제29권3호
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• pp.21-31
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• 2023

In this paper, we introduce a case study of cinematography using digital human in virtual production. This case study deals with the system overview of virtual production using LEDs and an efficient filming pipeline using digital human. Unlike virtual production using LEDs, which mainly project the background on LEDs, in this case, we use digital human as a virtual actor to film scenes communicating with a real actor. In addition, to film the dialogue scene between the real actor and the digital human using a real-time engine, we automatically generated speech animation of the digital human in advance by applying our Korean lip-sync technology based on audio and text. We verified this filming case by using a real-time engine to produce short drama content using real actor and digital human in an LED-based virtual production environment.

• Journal of KIBIM
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• 제12권4호
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• pp.80-92
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• 2022

Recently, remote work has arisen due to the social atmosphere and advancement of digital technology. Although effective in premeditated communications such as conferences or meetings, the current technology such as messengers and video chats insufficiently supports impromptu communications like a chance encounter, daily conversation with colleagues, or brief instant meetings. This causes various problems such as a decrease in social belonging and an increase in social isolation. The virtual workplace, which emerged as an alternative to this technology, is merely replicating the workplace layouts in reality with an absence of the proper design guideline. Therefore, this paper aims to establish the foundation for the better design of the virtual workplace for remote-work employees. The research compared 12 current workplace cases with the analysis with 5 categories(Spatial Composition, Scale, Individual & Collaboration Workplace, Socializing Space), and discovered the following results: 1) some design principles of the real workplace can be applied on the virtual workplace design, 2) the architectural components of the virtual workplace can differ from them of the real. Based on the results, the research suggests both the appropriate design methodologies of the virtual workplace considering the design principles of the real office layouts, and the design direction for the future of the virtual workplace. This research will be the foundation for the future design of the virtual workplace.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.801-806
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• 2008

This paper proposes an augmented reality application called augmented book. The augmented book provides an interface to the virtual objects and virtual environments using a real book. In the augmented book a user observes and manipulates the 3D visualization of virtual objects. Three different types of markers are introduced for the manipulation of virtual objects. By moving the control marker, the user controls the virtual objects. Our augmented book can be used as an interface for various kinds of 3D contents such as contents of real books or product catalogs.

• Journal of Korea Multimedia Society
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• 제7권8호
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• pp.1097-1106
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• 2004

The typical web cluster architecture consists of replicated real servers and a virtual server that routes client requests among the real servers. In this paper, we proposed an efficient dynamic load distribution method with load prediction for the web cluster systems. The virtual server transmit status request message to real servers in other to get load states. However the load states dose not accurate during load distribution, thus the virtual server predict the load status of real servers and assign a request of the client to the minimum loaded real server. The proposed distribution methods works not related to partial breakdown of real servers, thus the system works with high availability. We also show that the proposed distribution method preserve scalable property and improve the throughput through a set of simulations.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2009년도 학술대회
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• pp.310-314
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• 2009

In this paper we propose the U-VR Simulator which seamlessly connects entities in real and virtual environments by exploiting context, based on the concept of ubiquitous virtual reality. Using the U-VR Simulator, a smart home environment can be simulated and new virtual entities such as sensors, actuators, and services can be added to existing real entities. The proposed approach is fast and cost-effective because the simulator effectively utilizes both existing and simulated devices. In addition, our approach allows application developers to rapidly develop U-VR applications and extend them to relevant domains. As a future work, we will expand our simulator to intelligently augment virtual entities into real environments.

• Journal of Ubiquitous Convergence Technology
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• 제2권2호
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• pp.67-77
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• 2008

Representation of various types of information in an interactive virtual reality environment on mobile devices had been an attractive and valuable research in this new era. Our main focus is presenting spatial indoor location sensing information in 3D perception in mind to replace the traditional 2D floor map using handheld PDA. Designation of 3D virtual reality by Virtual Reality Modeling Language (VRML) demonstrates its powerful ability in providing lots of useful positioning information for PDA user in real-time situation. Furthermore, by interpolating portal culling algorithm would reduce the 3D graphics rendering time on low power processing PDA significantly. By fully utilizing the CC2420 chipbased sensor nodes, wireless sensor network was established to locate user position based on Received Signal Strength Indication (RSSI) signals. Implementation of RSSI-based indoor tracking method is low-cost solution. However, due to signal diffraction, shadowing and multipath fading, high accuracy of sensing information is unable to obtain even though with sophisticated indoor estimation methods. Therefore, low complexity and flexible accuracy refinement algorithm was proposed to obtain high precision indoor sensing information. User indoor position is updated synchronously in virtual reality to real physical world. Moreover, assignment of magnetic compass could provide dynamic orientation information of user current viewpoint in real-time.

• Proceedings of the Korean Institute of Building Construction Conference
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.224-225
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• 2019

Virtual reality technology can be defined as human-computer interface that makes virtual place of specific environments or situation is an interactive computer-generated experience taking place within a simulated environment. In order to combine virtual reality technology of domestic nuclear power industry, the R&D Project has been developing a virtual/augment reality system for nuclear power plant from April 2018 to March 2021. To effectively apply virtual reality technology of domestic nuclear industry, it is necessary to build virtual space similar to real environment. Therefore, This study is analysed 3d model status for nuclear power plant during the life-cycle, and suggested a method to build 3D cad model close to real environment.

• Journal of Power Electronics
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• 제17권1호
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• pp.282-293
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• 2017

There exists a strong coupling between real and reactive power owing to the complex impedances in droop based islanded microgrids (MGs). The existing virtual impedance methods consider improvements of the impedance matching for sharing of the voltage controlled power (VCP) (reactive power for Q-V droop, and real power for P-V droop), which yields a 1-DOF (degree of freedom) tunable virtual impedance. However, a weak impedance matching for sharing of the frequency controlled power (FCP) (real power for $P-{\omega}$ droop, and reactive power for $Q-{\omega}$ droop) may result in FCP overshoots and even oscillations during load transients. This in turn results in VCP oscillations due to the strong coupling. In this paper, a 2-DOF tunable adaptive virtual impedance method considering impedance matching for both real and reactive power (IM-PQ) is proposed to improve the power sharing performance of MGs. The dynamic response is promoted by suppressing the coupled power oscillations and power overshoots while realizing accurate power sharing. In addition, the proposed power sharing controller has a better parametric adaptability. The stability and dynamic performances are analyzed with a small-signal state-space model. Simulation and experimental results are presented to investigate the validity of the proposed scheme.

• The Journal of the Korea institute of electronic communication sciences
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• 제18권6호
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• pp.1229-1238
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• 2023

Digital twin is a technology that creates a virtual space that replicates the real world and manages the real world efficiently by integrating the real and virtual spaces. The digital twin concept for water facilities is to effectively manage water pipes in the real world by implementing them in a virtual space and augmenting them to the interior space of the building. In the proposed method, the Unity 3D game engine is used to implement the application of digital twin technology in the interior of a building. The AR Foundation toolkit based on ARCore is used as the augmented reality technology for our Digital Twin implementation. In digital twin applications, it is essential to match the real and virtual worlds. In the proposed method, 2D image markers are used to match the real and virtual worlds. The Unity shader program is also applied to make the augmented objects visually realistic. The implementation results show that the proposed method is simple but accurate in placing water pipes in real space, and visually effective in representing water pipes on the wall.