• Journal of the Korea Computer Graphics Society
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• v.22 no.3
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• pp.89-99
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• 2016

One of the fundamental elements in developing mixed reality applications is to effectively analyze and apply the environmental lighting information to image synthesis. In particular, interactive applications require to process dynamically varying lighting sources in real-time, reflecting them properly in rendering results. Previous related works are not often appropriate for this because they are usually designed to synthesize photorealistic images, generating too many, often exponentially increasing, light sources or having too heavy a computational complexity. In this paper, we present a fast light source estimation technique that aims to search for primary light sources on the fly from a sequence of video images taken by a camera equipped with a fisheye lens. In contrast to previous methods, our technique can adust the number of found light sources approximately to the size that a user specifies. Thus, it can be effectively used in Phong-illumination-model-based direct illumination or soft shadow generation through light sampling over area lights.

• Journal of Korea Multimedia Society
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• v.14 no.3
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• pp.440-448
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• 2011

The needs for the OpenGL-family of the rendering library standards are highly increasing, especially for the graphical human-machine Interface on the various systems including smart phones and personal information devices. Additionally, in the case of safety-critical market for avionics, military, medical and automotive applications, OpenGL SC, the safety critical profile of the OpenGL library plays the major role for the graphical interfaces. In this paper, we represent our OpenGL SC emulation library on the OpenGL 1.x rendering pipeline which is widely available on the existing embedded systems, to provide the features of OpenGL SC standard cost-effectively. Our method can provide the OpenGL SC features at the low development cost on the embedded systems, and its implementation is also one of the fundamental elements for the emulation of embedded systems in the PC environment. Our final result now works on both of Linux-based and VxWORKS systems, showing correct execution results at the reasonable speed.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.5
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• pp.79-86
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• 2005

The Qis visualizational spreadsheet environment is shown to be extremely effective in supporting the organized visualization of multi-dimensional data sets. The Qis consists of the reconfigurative 2D arrangement of spreadsheet elements at run time and each spreadsheet element has a novel framestack. As the feature, it supports 3D data structure of each element on the Qis. It enables the visualization spreadsheet to effectively manage, rapidly organize, and compactly encapsulate multi-dimensional data sets for visualization. Using several experiments with scientific users, the Qis has been demonstrated to be a highly interactive visual browsing tool for the analysis of multidimensional data, displaying 2D and 3D graphics, and rendering in each frame of the spreadsheet.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.177-186
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• 2006

This paper presents the development of a certain highly efficient authoring tool for constructing realistic 3D virtual space using image-based rendering techniques based on a virtual space map. Unlike conventional techniques such as TIP, for constructing a small 3D virtual space using single image, the authoring tool developed herein produces a wide 3D virtual space using multiple images. This tool is designed for constructing each small 3D virtual space for each input image, and for interconnecting these 3D virtual spaces into a wide 3D virtual space using a virtual space map. The map consists of three elements such as specific room, link point and passageway, and three directions. It contains various information such as the connection structure, the navigation information and so on. Also, the tool contains a user interface that let users construct the wide 3D virtual space easily.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1442-1449
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• 2007

Shadows are important elements for realistic rendering of the 3D scene. We cannot recognize the distance of objects in the 3D scene without shadows. Two methods, image-based medthods and object-based methods, are largely used for the rendering of shadows. Object based methods can generate accurate shadow boundaries. However, it cannot be used to generate the realtime shadows because the time complexity defends on the complexity of the 3D scene. Image based methods which are techniques to generate shadows are widely used because of fast calculation time. However, this algorithm has aliasing problems. PCF is a method to solve the aliasing problem. Using PCF technique, antialiased shadow boundaries can be generated. However, PCF with large filter size requires more time to calculate antialiased shadow boundaries. This paper proposes an improved PCF technique which generates antialiased shadow boundaries similar to that of PCF. Compared with PCF, this technique can generate antialiased shadows in less time.

• Archives of design research
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• no.18
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• pp.25-34
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• 1996

Industrial design development methods and processes have changed in accordance with Industrial Information Age. These days, problems are created by existing methods and evaluation of design value , all problems concerned with time and finances sitaution have been made a subject of discussion. Development of design processes have been changed by the development of problem recognition and solving tools, and dpsign tpchnulugy havp hppn replaced by computer technology,Thus. software design processes linking thoughtware to hardware are used in the solution of design problems with many parts. In this study, 3D Modeling samples are presented, 3D Modeling can realise ' Ideas' to '3Dimentional Virtual Ohjects'. These effect and value are anle to decisively influence the process of design problem conference-ebealuation-solution.Proxesses of actual modeling and rendering are made as follows. By compusition of simple 20 drawings and shaping them into 30 objects, 30 solid models can be made. To prssent effectivley, we can make a sample model by varying camera views,light sourses,materials and colours etc. This sample is evaluated by various cumposition, methods and PERT(Program Evaluation and Review Technique). This cuncrete sample (tentative plan)is changed within the CAD SYSTEM by design evaluation, and then converted to flowchart of mass productive conception through refined data. So, that tentative plan can be conformed to design desire actuillly, to the utmost degree. Finally, this design process can be proposed as il new method in cuntrast with current methods. The aim of this study is to suggest effective evaluation methods of design outcome among many evaluating elements.

• Journal of KIISE:Computer Systems and Theory
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• v.29 no.5
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• pp.245-256
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• 2002

Shadows are important elements in producing a realistic image. Generation of exact shapes and positions of shadows is essential in rendering since it provides users with visual cues on the scene. It is also very important to be able to create soft shadows resulted from area light sources since they increase the visual realism drastically. In spite of their importance. the existing shadow generation algorithms still have some problems in producing realistic shadows in real-time. While image-based rendering techniques can often be effective1y applied to real-time shadow generation, such techniques usually demand so large memory space for storing preprocessed shadow maps. An effective compression method can help in reducing memory requirement, only at the additional decoding costs. In this paper, we propose a new image-barred shadow generation method based on image warping. With this method, it is possible to generate realistic shadows using only small sizes of pre-generated shadow maps, and is easy to extend to soft shadow generation. Our method will be efficiently used for generating realistic scenes in many real-time applications such as 3D games and virtual reality systems.

• Management Science and Financial Engineering
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• v.14 no.2
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• pp.45-66
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• 2008

Refuse collection, one of important elements in reverse logistics, is an activity rendering recyclables or wastes and moving them to some points where further treatment is required. Among various decisions in the collection activity, we focus on network design, which is the problem of locating collection points as well as allocating refuses at demand points to collection points while satisfying the capacity restriction at each collection point. Here, the collection point is the place where recyclables or wastes near the point are gathered, and locating the collection points is done by selecting them from a given set of potential sites. The objective is to minimize the sum of fixed costs to open collection points and transportation costs to move refuses from demand points to collection points. An integer programming model is developed to represent the problem mathematically and due to the complexity of the problem, two types of heuristics, one with simultaneous and the others with separate location and allocation, are suggested. Computational experiments were done on test problems up to 500 potential sites, and the results are reported. In particular, some heuristics gave near optimal solutions for small-size test problems, i.e., 2% gaps in average from the optimal solution values.

• Journal of the Korean Society of Costume
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• v.41
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• pp.23-47
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• 1998

Ornaments is a province of the fashion. It usually express noble metals and jewel's adorn-ment as the symbol of status and riches for a long time. The ornament design of Jewels drawing project and a product by computer are increased development and as exertion as a realization of automation. Through the use of CAD software(Auto CAD R 13 & Jewel CAD) \circled1 A design development of the jewels in industrial society \circled2 A metals art & design on the dress and it's ornaments - Study about application of principle(liberal curve, arrangement of repeated form, gradual unity, rhythmical harmony) Although Auto CAD don't various expression of Jewels than a Jewel CAD, formative.scientific.funtional development of geometrical form is free. That is (to say), geometrical form is given much weigh in the general CAD, but Jewel CAD made concentrate software on the jewels design for the expression of liberal form. The CAD/CAM software for jewellery program is composed of main menu, icons, hotkeys. Changing form is derived from a definite point, curve elements of a drawing. \circled1 3-Dimensional \circled2 Easy and flexible \circled3 Bulit-in and self created library \circled4 From simple wire frame to full color images. As a CAD can practice all the creation activity effectively, from Design & Drafting Software to Rendering generally can present precise results. A point of view of the connection the scientist and art, this practicableness of CAD have a lot of possiblity of development. That will do much for the related fields of industry. Consequently, subjective intension of a creator & humanity with value plays role in practical application of the design.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.2
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• pp.207-225
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• 1992

The study is concerned with the thermo-viscoplastic finite element analysis of axisymmetric forward hot extrusion through square dies. The problem is treated as a nonsteady state problem because the distribution of temperature and material properties are continuously changing with the punch travel. In square die extrusion, difficulties arise from the severe distortion and die interference of elements at the aperture rim of the die even with a small punch travel. And finite element computation is impossible without intermittent remeshing. Accordingly, an automatic remeshing technique is proposed by employing specially designed mesh structure near the aperture rim. The analysis of temperature distribution includes heat conduction through material interfaces, heat convection and radiation to the atmosphere and is carried out by decoupling the heat analysis from the analysis of the deformation. The extrusion load and the distributions of strain rate and temperature are computed for the given cases rendering reasonable results. Computed grid distortions are found to be in good agreement with the experimental results. It has been thus shown that the proposed method of analysis can be effectively applied to the axisymmetric hot extrusion through square dies.