• Journal of the Korea Computer Graphics Society
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• v.26 no.4
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• pp.9-15
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• 2020

Having a virtual talking face along with a virtual body increases immersion in VR applications. As virtual reality (VR) techniques develop, various applications are increasing including multi-user social networking and education applications that involve talking avatars. Due to a lack of sensory information for full face and body motion capture in consumer-grade VR, most VR applications do not show a synced talking face and body. We propose a novel method, targeted for VR applications, for talking face synced with audio with an upper-body inverse kinematics. Our system presents a mirrored avatar of a user himself in single-user applications. We implement the mirroring in a single user environment and by visualizing a synced conversational partner in multi-user environment. We found that a realistic talking face avatar is more influential than an un-synced talking avatar or an invisible avatar.

• Journal of the Korea Computer Graphics Society
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• v.24 no.2
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• pp.11-20
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• 2018

We propose a new method particle-based method that explicitly preserves thin liquid sheets for animating liquids on CPU-GPU heterogeneous computing framework. Our primary contribution is a particle-based framework that splits at thin points and collapses at dense points to prevent the breakup of liquid on GPU. In contrast to existing surface tracking methods, the our method does not suffer from numerical diffusion or tangles, and robustly handles topology changes on CPU-GPU framework. The thin features are detected by examining stretches of distributions of neighboring particles by performing PCA(Principle component analysis), which is used to reconstruct thin surfaces with anisotropic kernels. The efficiency of the candidate position extraction process to calculate the position of the fluid particle was rapidly improved based on the CPU-GPU heterogeneous computing techniques. Proposed algorithm is intuitively implemented, easy to parallelize and capable of producing quickly detailed thin liquid animations.

• Journal of the Korea Computer Graphics Society
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• v.18 no.2
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• pp.55-62
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• 2012

This paper presents a new method to represent the secondary deformation effect using simple mass-spring simulation on the vertex shader of the GPU. For each skin vertex of a 3D character, a zero-length spring is connected to a virtual vertex that is to be rendered. When a skin vertex changes its position and velocity according to the character motion, the position of the corresponding virtual vertex is computed by mass-spring simulation in parallel on the GPU. The proposed method represents the secondary deformation effect very fast that shows the material property of a character skin during the animation. Applying the proposed technique dynamically can represent squash-and-stretch and follow-through effects which have been frequently shown in the traditional 2D animation, within a very small amount of additional computation. The proposed method is applicable to represent elastic skin deformation of a virtual character in an interactive animation environment such as games.

• The Journal of the Korea Contents Association
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• v.11 no.11
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• pp.19-27
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• 2011

In this paper, we present an emulation library for the essential features and their API function calls provided by Direct3D, the most actively used API for computer game-related application programs on the MS-Windows-based desktop's, with OpenGL library in the Linux environment. In typical Linux-based systems, only the X window system and OpenGL graphics library are available. There are lots of needs for this kind of emulation library to convert the Direct3D-based game applications and user interfaces on these systems. Through carefully selecting the essential API functions from the DirectX version 9.0, we obtained the prototype implementation of that emulation library, to finally get the final full-scale DirectX implementation. Our implementation currently covers 3D coordinate transformations, light and material processing, texture mapping, simple animation features and more. We showed its feasibility through successfully executing a set of Direct3D demonstration programs including a real-world game character animation on our implementation.

• Proceedings of the Korean Information Science Society Conference
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• 2006.10d
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• pp.750-753
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• 2006

e-Learning 분야는 정부, 기업, 학교 등 많은 조직에서 교육을 위한 수단으로 사용되어지고 있다. 이러한 e-Learning은 독립적인 운영플렛폼의 개발부터 웹 기반의 코스웨어(Courseware)까지 발전해왔다. 코스웨어는 컴퓨터 전달 체제를 통하여 교수-학습 과정을 촉진시켜 명시된 교수 목표 하에 학습자의 지식과 기능의 바람직한 변화를 목적으로 설계 및 개발된 교육용 소프트웨어와 데이터라고 할 수 있다. 또한 컴퓨터 언어 및 저작도구(Authoring Tools)를 이용하여 각 과목별 교육내용을 음성, 그림, 애니메이션, 동영상 등의 다양한 형태로 제시될 수 있도록 저작된 프로그램으로 주로 눈으로 보고 귀로 들으면서 학습하는 유형이다. 현재 코스웨어에서 제공되는 정보는 학습에 대한 정보와 교수정보 그리고 Client의 학습 진행 상황 등을 제공한다. 하지만 학습에 연관된 다른 학습이나 학습에 관련된 교수들의 전공정보, 또한 학습에 관련된 어플리케이션 등을 검색하려 할 때는 하나하나 따로 검색을 해야 하는 어려움이 따른다. 본 논문에서는 이러한 문제점을 해결하기 위하여 학습에 대한 목적과 관련학습, 관련교수, 관련연구, 관련 어플리케이션 등의 연관성을 토픽맵(TopicMap)을 이용하여 학습에 대한 더 정확한 정보를 쉽게 검색할 수 있게 한다. Client가 찾으려는 토픽을 중심으로 연관된 토픽과 카테고리를 나열하여 수작업으로 인한 검색시간과 잘못된 키워드 검색을 해결하였다.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.253-261
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• 2008

Mobile games will be one of independent industries on game areas and take the fourth standing in the important platform since PC Games, TV Games, and Palm Games. There are several reasons why mobile games will differ in their platform, behaviors, and habits. According to the data of market consultation about the figure of mobile-game players throughout the world, the Mobile game will increase steadily from 780 million in 2007 to 1860 million in 2010. Also, market income will mount up from $42,100 million to $87,000 million. 3D games have been playing important roles in our lives. Satisfying users' needs in high-quality games, they have been growing and attracting more people with their powerful visual effects and the three-dimensional design player. We cannot emphasize their tremendous visual impacts and animation effects too much. This paper displays how to design 3D application based on J2ME (Java 2 Micro Edition) and shows free movement of 3D objects receiving and responding to the keyboard of mobile devices withWTK (Wireless ToolKit) simulator on the 3D screen.

• Journal of the Korea Computer Graphics Society
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• v.23 no.2
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• pp.23-27
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• 2017

We propose an inter-leg collision avoidance method that compensates the disadvantage of the data-driven biped control method. The data-driven biped control technique proposed by Lee et. al [1] sometimes generates the movement that the two legs intersect with each other while walking, which can not be realized in walking of a real person or a biped robot. The proposed method changes the angle of the swing hip so that the swing foot can move inward only after passing the stance foot. This process introduces an additional angle adjustment algorithm to avoid collisions with the stance leg to the original feedback rule of the stance hip. It generates a stable walking simulation without any inter-leg collisions, by adding minimal changes and additional calculations to the existing controller behavior.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.49-55
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• 2010

The analysis of menu preference by different users is one of the important issues in mobile interface design. Current mobile phones do not provide any functionalities to customize the user interface based on use history after they are released by manufacturers or mobile carriers. Though a number of functions are loaded into mobile devices, all the menus are uniformly presented to users regardless of menu preference, and it becomes a reason to decrease the usability of mobile interface. To improve this limitation, this paper suggests how to apply 3D visualization methods to mobile interface, depending on menu use history. In addition, for performance evaluation, 3D mobile interface system was implemented using 3D visualization methods such as depth, transparency, and animation. Finally, experiments for performance evaluation were performed in order to measure and compare menu search times.

• Journal of the Korea Society of Computer and Information
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• v.20 no.5
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• pp.21-29
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• 2015

This paper proposes a shot change detection algorithm by using frame segmentation and the object changes among moving blocks. In order to detect the rapid moving changes of objects between two consecutive frames, the moving blocks on the diagonal are defined, and their histograms are calculated. When a block of the current frame is compared to the moving blocks of the next frame, the block histograms are used and the threshold of a shot change detection is automatically adjusted by Otsu's threshold method. The proposed algorithm was tested for the various types of color or gray videos such as films, dramas, animations, and video tapes in National Archives of Korea. The experimental results showed that the proposed algorithm could enhance the detection rate when compared to the studied methods that use brightness, histogram, or segmentation.

• Journal of the Korea Society of Computer and Information
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• v.10 no.3 s.35
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• pp.55-64
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• 2005

The avatar can be used as an auxiliary methodology of text and image communications in cyber space. An intelligent communication method can also be utilized to achieve real-time communication, where intelligently coded data (joint angles for arm gestures and action units for facial emotions) are transmitted instead of real or compressed pictures. In this paper. for supporting the action of arm and leg gestures, a method of generating the facial expressions that can represent sender's emotions is provided. The facial expression can be represented by Action Unit(AU), in this paper we suggest the methodology of finding appropriate AUs in avatar models that have various shape and structure. And, to maximize the efficiency of emotional expressions, a comic-style facial model having only eyebrows, eyes, nose, and mouth is employed. Then generation of facial emotion animation with the parameters is also investigated.