• Journal of Korea Game Society
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• v.15 no.6
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• pp.97-106
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• 2015

In an Unity engine for multi-player online games, the main thread processing game logic must be separated from the network thread that is responsible for network packet communication. Packet communication between the network threads needs to drop packets that overlap in order to improve the rendering speed. In this paper, the packet discard policy of network thread is proposed for an Unity engine for multi-player online games. The proposed method is the hybrid method of both Partial Packet Discard and Periodic Packet Discard methods to improve the rendering speed by periodically discarding overlapped network packets managed by the queue. The rendering speed of the proposed method is analyzed and its effectiveness is verified by various packet generating simulations of the Unity engine for multi-player online games.

• Journal of Korea Game Society
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• v.11 no.6
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• pp.71-80
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• 2011

Recent terrain rendering applications such as 3D games and virtual reality, use GPU-based ray-casting method for rendering high-quality scenes in realtime. As the size of terrain dataset grows bigger, the rendering speed will be decreased by the increase of the number of texture samplings. To accelerate the conventional ray-casting, we propose an efficient ray casting method with subdivided bounding boxes which are based-on GPU quadtree traversal. The subdivision of the terrain's bounding box can reduce the empty spaces effectively. By performing the ray-casting with this compact bounding box, we can efficiently reduce computation with empty space skipping. Unlike the recent quadtree-based empty space skipping techniques which perform the tree traversal at each ray, our method traverses the tree only once per frame. Therefore, we can save much computational time.

• Journal of the Korea Society for Simulation
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• v.16 no.3
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• pp.57-63
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• 2007

In real time rendering of fetus the empty space leaping while traversing a ray is most frequently used accelerating technique. The main idea is to skip empty voxel samples which do not contribute the result image and it speeds up the rendering time by avoiding sampling data while traversing a ray in the empty region, saving a substantial number of interpolations. Calculating the distance from the nearest object boundary for every yokel can reduce the sampling operation. Among widely-well-known distance maps, those estimates the true distance, such as euclidean distance, takes a long time to compute because of the complicated floating-point operations, and others which uses approximated distance functions, such as city-block and chessboard, provides faster computation time but sampling error may can occur. In this paper, therefore, we analyze the characteristics of several distance maps and compare the number of samples and rendering time. And we aim to suggest the most appropriate distance map for rendering of fetus in ultrasound image.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.7
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• pp.1363-1368
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• 2016

Fast rendering speed is one of key functions to provide realistic scenes in flight simulator. However, since flight simulator mostly operates with high volume terrain data, rendering speed is reduced and changed very rapidly when it handles file containing too much vertexs. So, previous schemes make use of Level of Details (LOD) scheme to prevent this problem. But, since LOD is applied after the large number of vertexs are detected, transition between scenes is not completely smooth. To solve this problem, in this paper, we propose a new dynamic LOD scheme which controls LOD level in advance through prediction of vertex overload. To verify the proposed scheme, we implement the proposed scheme in our flight simulation through OpenSceneGraph(OSG) and identify the reduced number of vertexs and enhanced Frame Per Second (FPS) by comparing real data with predicted one.

• Journal of the Korea Computer Graphics Society
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• v.17 no.2
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• pp.1-9
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• 2011

In recent researches, several LOD techniques are used for real-time visualization of large sized terrain data. However, during mesh simplification, geometry popping may occur in consecutive frames, because of the geometric error. We propose an efficient method for reducing the geometry popping using roughness map and bias map. A roughness map and a bias map are used to move vertices of the terrain mesh to appropriate position where they minimize the geometry errors. A roughness map and a bias map are represented as a texture suitable for GPU processing. Moving vertices using bias map is processed on the GPU, so the high-speed visualization can be possible.

• Journal of the Korea Computer Graphics Society
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• v.18 no.4
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• pp.25-34
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• 2012

This paper presents a real-time GPU (graphics processing unit) ray casting scheme for rendering isosurfaces of BCC (body-centered cubic) volume datasets. A quartic spline field is built using the 7-direction box-spline filter accompanied with a quasi-interpolation prefilter. To obtain an interactive rendering speed on the graphics hardware, the shader code was optimized to avoid lookup table and conditional branches and to minimize data fetch overhead. Compared to previous implementations, our work outperforms the comparable one by more than 20% and the rendering quality is superior than others.

• The KIPS Transactions:PartA
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• v.16A no.3
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• pp.153-158
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• 2009

Analysis of 3-dimensional (3D) protein structure plays an important role of structural bioinformatics. The protein structure visualization is the one of the structural bioinformatics and the most fundamental problem. As the number of known protein structure increases rapidly and the study of protein-protein interaction is prevalent, the fast visualization of large scale protein structure becomes essential. The fast protein structure visualization system we proposed is sophisticated and well designed visualization system using geometry instancing technique. Because this system is optimized for recent 3D graphics hardware using geometry instancing technique, its rendering speed is faster than other visualization tools.

• 한국HCI학회:학술대회논문집
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• 2008.02c
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• pp.224-224
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• 2008

Recent advances in model acquisition, computer-aided design, and simulation technologies have resulted in massive databases of complex geometric data occupying multiple gigabytes and even terabytes. In various graphics/geometric applications, the major performance bottleneck is typically in accessing these massive geometric data due to the high complexity of such massive geometric data sets. However, there has been a consistent lower growth rate of data access speed compared to that of computational processing speed. Moreover, recent multi-core architectures aggravate this phenomenon. Therefore, it is expected that the current architecture improvement does not offer the solution to the problem of dealing with ever growing massive geometric data, especially in the case of using commodity hardware. In this tutorial, I will focus on two orthogonal approaches--multi-resolution and cache-coherent layout techniques--to design scalable graphics/geometric algorithms. First, I will discuss multi-resolution techniques that reduce the amount of data necessary for performing geometric methods within an error bound. Second, I will explain cache-coherent layouts that improve the cache utilization of runtime geometric applications. I have applied these two techniques into rendering, collision detection, and iso-surface extractions and, thereby, have been able to achieve significant performance improvement. I will show live demonstrations of view-dependent rendering and collision detection between massive models consisting of tens of millions of triangles on a laptop during the talk.

• Journal of Broadcast Engineering
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• v.25 no.5
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• pp.655-664
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• 2020

Free viewpoint image synthesis technology is one of the important technologies in the MPEG-I (Immersive) standard. RVS (Reference View Synthesizer) developed by MPEG-I and in use in MPEG group is a DIBR (Depth Information-Based Rendering) program that generates an image at a virtual (intermediate) viewpoint from multiple viewpoints' inputs. RVS uses the mesh surface method based on computer graphics, and outperforms the pixel-based ones by 2.5dB or more compared to the previous pixel method. Even though its OpenGL version provides 10 times speed up over the non OpenGL based one, it still shows a non-real-time processing speed, i.e., 0.75 fps on the two 2k resolution input images. In this paper, we analyze the internal of RVS implementation and modify its structure, achieving 34 times speed up, therefore, real-time performance (22-26 fps), through the 3 key improvements: 1) the reuse of OpenGL buffers and texture objects 2) the parallelization of file I/O and OpenGL execution 3) the parallelization of GPU shader program and buffer transfer.

• Journal of Biomedical Engineering Research
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• v.19 no.2
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• pp.189-198
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• 1998

3D medical image reconstruction techniques are useful to figure out complex 3D structures from the set of 2D sections. In the paper, 3D medical image reconstruction system is constructed under PC environment and programmed based on modular programming by using Visual C++ 4.2. The whole procedures are composed of data preparation, gradient estimation, classification, shading, transformation and ray-casting & compositing. Three speed optimization techniques are used for accelerating 3D medical image reconstruction technique. One is to reduce the rays when cast rays to reconstruct 3D medical image, another is to reduce the voxels to be calculated and the other is to apply early ray termination. To implement 3D medical image reconstruction system based on PC, speed optimization techniques are experimented and applied.