• Journal of KIISE:Computer Systems and Theory
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• v.27 no.7
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• pp.619-628
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• 2000

Abstract Perspective views provide a powerful depth cue and thus aid the interpretation of complicated images. The main drawback of current perspective volume rendering is the long execution time. In this paper, we present an efficient perspective volume rendering algorithm based on coherency between rays. Two sets of templates are built for the rays cast from horizontal and vertical scanlines in the intermediate image which is parallel to one of volume faces. Each sample along a ray is calculated by interpolating neighboring voxels with the pre-computed weights in the templates. We also solve the problem of uneven sampling rate due to perspective ray divergence by building more templates for the regions far away from a viewpoint. Since our algorithm operates in object-order, it can avoid redundant access to each voxel and exploit spatial data coherency by using run-length encoded volume. Experimental results show that the use of templates and the object-order processing with run-length encoded volume provide speedups, compared to the other approaches. Additionally, the image quality of our algorithm improves by solving uneven sampling rate due to perspective ray di vergence.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.6
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• pp.273-282
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• 2016

Visualization tool can be divided by three components - data I/O, visual transformation and interactive rendering. In this paper, we present requirements of three major components on visualization tools for massive scientific dataset and propose strategies to develop the tool which satisfies those requirements. In particular, we present how to utilize open source softwares to efficiently realize our goal. Furthermore, we also study the way to combine several open source softwares which are separately made to produce a single visualization software and optimize it for realtime visualization of massiv espatio-temporal scientific dataset. Finally, we propose a distributed shared memory based scientific visualization tool which is called "GLOVE". We present a performance comparison among GLOVE and well known open source visualization tools such as ParaView and VisIt.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1885-1888
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• 2004

In order to render 3D model of the bone, the stack of cross-sectional images must be reconstructed from a series of X-ray radiographs, served as the projections. In the case where the distance between x-ray source and detector is not infinite, image reconstruction from projection based on parallel-beam geometry provides an error in the cross-sectional image. In such case, image reconstruction from projection based on conebeam geometry must be exercised instead. This paper is devoted to the determination of detector center for SART conebeam Technique which is critically effect the performance of the resulting 3D modeling.

• Journal of KIISE:Computer Systems and Theory
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• v.26 no.1
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• pp.82-97
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• 1999

3차원 그래픽 렌더링은 화면상의 각 화소에 대하여 색깔뿐만 아니라 깊이 정보가지 계산해야 하기 때문에 방대한 계산량과 메모리 접근, 그리고 데이터 전송량을 필요로 하기 때문이다. 따라서 실시간 3차원 그래픽 처리를 위해서 병렬 처리 기법을 도입한다. 그러나 기존 그래픽 가속엔진은 병렬처리 기법으로 영상-병렬성을 이용한 화면 분할 방식을 사용하기 때문에 크게 두 가지 단점이 발생한다. 첫 번재는 화면 영역의 경게에 위치하는 다각형들에 대한 중복계산이고, 두 번째는 낮은 PE(Processing Element) 활용도이다. 본 논문에서는 이러한 문제를 해결하기 위한 방법으로 객체 기반 렌더링(OBR : Object Based Rendering)방식을 바탕으로 하는 그래픽 가속엔진을 제안하였다. OBR 시스템의 목적은 화면 분할 방식의 불필요한 오버헤드를 제거하여 수행 성능을 높이고, 자원을 효율적으로 사용하여 하드웨어 구성비용을 줄이는 것이다. 본 논문에서는 시뮬레이션을 통하여 OBR 시스템이 화면 분할 방식의 대표적인 그래픽 가속기인 PixelFlow와의 성능을 상대적으로 비교하였다. 결론적으로 OBR 시스템은 화면 분할 방식보다 더 적은 하드웨어 자원으로 보다 효율적으로 렌더링을 수해하였다.

• Journal of the HCI Society of Korea
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• v.1 no.1
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• pp.37-44
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• 2006

Specular reflections provide the visual feedback that describes the material type of an object, its local shape, and lighting environment. In photorealistic rendering, there have been a number of research available to render specular reflections effectively based on a local reflection model. In traditional cel animations and cartoons, specular reflections plays important role in representing artistic intentions for an object and its related environment reflections, so the shapes of highlights are quite stylistic. In this paper, we present a method to render and control stylized specular reflections using projective textures based on principal curvature analysis. Specifying a texture as a pattern of a highlight and projecting the texture on the specular region of a given 3D model, we can obtain a stylized representation of specular reflections. For a given polygonal model, a view point, and a light source, we first find the maximum specular intensity point, and then locate the texture projector along the line parallel to the normal vector and passing through the point. The orientation of the projector is determined by the principal directions at the point. Finally, the size of the projection frustum is determined by the principal curvatures corresponding to the principal directions. The proposed method can control the position, orientation, and size of the specular reflection efficiently by translating the projector along the principal directions, rotating the projector about the normal vector, and scaling the principal curvatures, respectively. The method is be applicable to real-time applications such as cartoon style 3D games. We implement the method by Microsoft DirectX 9.0c SDK and programmable vertex/pixel shaders on Nvidia GeForce FX 7800 graphics subsystems. According to our experimental results, we can render and control the stylized specular reflections for a 3D model of several ten thousands of triangles in real-time.

• Archives of design research
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• v.4 no.1
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• pp.61-73
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• 1991

The exhibition activity that a company is rendering to their consumers for the purpose of advertisement, sales promotion and enhancement of company inage get more and more internationalized and specialized. A company is changing from mass production system to small quantity production of various kinds to meet consumer's individualization and differentiation. Also, a company is experiencing a major change in their marketing strategy. As the society is entering on Information Age, the contents that a company intends to give consumer may be different individually. If a consumer is informed wrong information of the goods, a company needs a place to meet consumer face to face where the consumer feels and understands the substance of the goods. This is the current characteristics of Exhibition Media. Based on the result of the current Special Exhibition home and abroad along with background and characteristics of special Exhibition, this study sets a following task reflecting the general trend of social, cultural and economic atmosphere. First, Current Exhibition Industry will be diversified into more Specialized Exhibition, while our Exhibition Industry is very shaky under severe international competition. Also, Exhibition Plan that involves with architecture, interior, graphic, industrial design and advertisement, etc., needs international competitiveness while enhancing identity of Exhibition Plan along with comprehensive marketing strategy in the future. Second, Among most of the local special Exhibitions which invite the general public are normally invited for company public relation contrary to those of U.S.A. and Europe. This signifies of our industrial and social structure's by-product. As the future exhibition become Information Com$$\mu$ication Exhibition which requires specialized technical explanation, the correct description of the goods should be set as a Judgement basis of Exhibition Plan. Third, In parallel with increase of the Exhibition, the equipment expenses of a company goes up continuously. In view of this, a study $$\mu$t be oriented for re-use and curtailment of expenditure of those equipment. Also, as the use of Assembly System B on the rise as a result of diversification of special Exhibition, a study on the development of new material & design for Exhibition Equipment only B required.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37 no.4C
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• pp.277-282
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• 2012

In this paper, we present a real-time eye contact system for realistic telepresence using a Kinect depth camera. In order to generate the eye contact image, we capture a pair of color and depth video. Then, the foreground single user is separated from the background. Since the raw depth data includes several types of noises, we perform a joint bilateral filtering method. We apply the discontinuity-adaptive depth filter to the filtered depth map to reduce the disocclusion area. From the color image and the preprocessed depth map, we construct a user mesh model at the virtual viewpoint. The entire system is implemented through GPU-based parallel programming for real-time processing. Experimental results have shown that the proposed eye contact system is efficient in realizing eye contact, providing the realistic telepresence.

• Journal of the Korean Society for Library and Information Science
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• v.23
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• pp.263-301
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• 1992

In recent years, Korean public libraries, placed under changing circumstances, require that some new and positive financial policies be formulated for the improvement of their services. T he purpose of this study is to propose a scheme to ensure the revenues of Korean public libraries. The main contents of this study are as follows : (1) Public finance theory is applied to the question of why the public library is publicly supported. The public library does not contribute to stabilization, but it does playa role in each of the other public sector functions : allocation of resources and redistribution of income. In public finance terms there is justification for at least partial subsidy of public library services, which have the attributes of public goods, merit goods and externalities. (2) Public libraries in Korea find themselves suffering from limited budgets. They are neglected in national and local budgets. The lack of adequate funding for library collections prevents libraries from rendering efficient services. (3) In order to put the finances of the Korean public library system on a firm basis, the following proposals are made: 1) It is proposed that the parallel administration under which public libraries are organized be unified to be directly under the local governments. 2) It is proposed that the legislative and administrative system for public library finance be strengthened. (1) Library expenses should be itemized independently in the calculation of general grants-in-aid to local governments. (2) A fixed portion of the total municipal revenue should be appropriated for public library services. It can be executed by making provisions expressly in the annual guidelines for budgeting, municipal ordinances, or in the Library Promotion Law. The rate of allocation should be specified as a part of the national public library development plan. (3) Library tax as a local tax can be imposed. An indirect tax is preferable in order to avoid public misunderstanding and antagonism. 3) The augmentation of the specific grants-in-aid for the public library is proposed. The Library Promotion Law and the Law on Budget and Administration of Grants should be amended to oblige the central government to give financial assistance to local public libraries. 4) It is proposed that strategies to encourage private endowments be worked out. Revision of the Law on Tax Reduction and Exemption and the activation of an advisory library committee at each public library are recommended. 5) Funding and utilization of the envisioned Library Promotion Foundation is proposed. Government contributions, contributions from the Culture and Arts Foundation, and donations from individuals, corporations, and enterprises can be considered as the financial resources of the Foundation. 6) It is proposed that the structure of the Korean Library Association be consolidated to exercise greater influence over the formation of national policy on the public library system. 7) It is proposed as an ultimate guarantee of the health of the public libraries that the citizenry be educated to strongly support library services in responce to the active services provided by the public libraries.

• Journal of the Korea Society of Computer and Information
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• v.16 no.11
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• pp.67-76
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• 2011

This paper describes the development of interactive visualization techniques and a program that allow us to visualize the structure of the volume data and interactively select and visualize the isosurface components using contour tree. The main characteristic of this technique is to provide an algorithm that draws the contour tree in 2D plane in a way that users easily understand the tree, and to provide an algorithm that can efficiently extract an isosurface component utilizing GPU's parallel architecture. The main characteristic of the program we developed through implementing the algorithms is to provide us with an interactive user interface based on the contour tree for extracting an isosurface component and visualization that integrates with previous isosurface and volume rendering techniques. To show the excelland vof our methods, we applied 3D biomedical volume data to our algorithms. The results show that we could interactively select the isosurface components that represent a polypeptide chain, a ventricle and a femur respectively using the user interface based on our contour tree layout method, and extract the isosurface components with 3x-4x higher speed compared to previous methods.