• Journal of the Korea Computer Graphics Society
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• v.26 no.4
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• pp.17-26
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• 2020

We present a real-time GPU(Graphic Processing Unit) marching tetrahedra technique that extracts isosurfaces in the indexed mesh format from BCC(Body Centered Cubic) volume datasets. Compared to classical marching tetrahedra, our method shows better performance with little memory overhead. Our technique is composed of five stages. In the first stage, which needs to be done only once, we build min/max blocks that is to be used for empty space skipping to boost the performance. Next, we extract active blocks that contain the current isovalue. In the next two stages, we extract the edges and cells that contain the isosurface and then the final triangular mesh is generated in the last stage. When applied 512³ or higher resolution volume dataset, our technique shows up to 5 times speed improvement compared to the classical marching tetrahedra algorithm.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.24 no.12B
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• pp.2391-2400
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• 1999

Vector quantizer (VQ) is an efficient data compression technique for low bit rate applications. However, the major disadvantage of VQ is its encoding complexity which increases dramatically as the vector dimension and bit rate increase. Even though one can use a modified VQ to reduce the encoding complexity, it is nearly impossible to implement such a VQ at a high bit rate or for a large vector dimension because of the enormously large memory requirement for the codebook and the very large training sequence (TS) size. To overcome this difficulty, in this paper we propose a novel structurally constrained VQ for the high bit rate and the large vector dimension cases in order to obtain VQ-level performance. Furthermore, this VQ can be extended to the low bit rate applications. The proposed quantization scheme has a form of feed-forward adaptive quantizer with a short adaptation period. Hence, we call this quantization scheme sample-adaptive product quantizer (SAPQ). SAPQ can provide a 2 ~3dB improvement over the Lloyd-Max scalar quantizers.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.25 no.2
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• pp.241-251
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• 2015

In public-key cryptographic system based on finite field arithmetic, it is very important to challenge for implementing high speed operation. In this paper, we focused on 8-bit ATmega128 processor and concentrated on enhancing efficiency of reduction operation which uses irreducible polynomial $f(x)=x^{271}+x^{207}+x^{175}+x^{111}+1$ and $f(x)=x^{193}+x^{145}+x^{129}+x^{113}+1$. We propose optimized reduction algorithms which are designed to reduce repeated memory accesses by calculating final reduced values of Fast reduction. There are 53%, 55% improvement when proposed algorithm is implemented using assembly language, compare to previous Fast reduction algorithm.

• 한국HCI학회:학술대회논문집
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• 2008.02b
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• pp.460-464
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• 2008

To improve and optimize user interfaces of the system, the accurate understanding of users' behavior is an essential prerequisite. Direct questions depend on user' s ambiguous memory and usability tests depend on the researchers' intention instead of users'. Furthermore, they do not provide with natural context of use. In this paper we described the work which examined users' behavior through log analysis in their own environment. 50 users were recruited by consumer segmentation and they were downloaded logging-software in their mobile phone. After two weeks, logged data were gathered and analyzed. The complementary methods such as a user diary and an interview were conducted. The result of the analysis showed the frequency of menu and key access, used time, data storage and several usage patterns. Also, it was found that users could be segmented into new groups by their usage patterns. The improvement of the mobile phone user interface was proposed based on the result of this study.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.3
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• pp.195-202
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• 1998

The LPCVD system of batch type for the massproduction of semiconductor fabrication has a problem of phosphorous concentration uniformity in the boat. In this paper we study an improvement of the uniformity for phosphorous concentration and sheet resistance. These property was improved by using the nitrogen process and modified long nozzle for gas injection tube in the doped polysilicon deposition system. The phosphorous concentration and its uniformity for polysilicon film are measured by XRF(X-ray Fluorescence) for the conventional process condition and nitrogen process. In conventional process condition, the phosphorous concentration, it uniformity and sheet resistance for polysilicon film are in the range of 3.8~5.4$\times$10\ulcorner atoms/㎤, 17.3% and 59~$\Omega$/ , respectively. For the case of nitrogen process the corresponding measurements exhibited between 4.3~5.3$\times$10\ulcorner atoms/㎤, 10.6% and 58~81$\Omega$/ . We find that in the nitrogen process the uniformity of phosphorous concentration improved compared with conventional process condition, however, the sheet resistance in the up zone of the boat increased about 12 $\Omega$/ . In modified long nozzle, the phosphorous concentration, its uniformity and sheet resistance for polysilicon films are in the range of 4.5~5.1$\times$10\ulcorner atoms/㎤, 5.3% and 60~65$\Omega$/ respectively. Annealing after $N_2$process gives the increment of grain size and the decrement of roughness. Modification of nozzle gives the increment of injection amount of PH$_3$. Both of these suggestion result in the stable phosphorous concentration and sheet resistance. The results obtained in this study are also applicable to process control of batch type system for memory device fabrication.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.46 no.2
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• pp.38-44
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• 2009

Bus system consists of several masters, slaves, arbiter and decoder in a bus. Master means the processor that performs data command like CPU, DMA, DSP and slave means the memory that responds the data command like SRAM, SDRAM and register. Furthermore, as multiple masters can't use a bus concurrently, arbiter plays an role in bus arbitration. In compliance with the selection of arbitration method bus system performance can be charged definitely. Fixed priority and round-robin are used in general arbitration method and TDMA and Lottery bus methods are proposed currently as the improved arbitration schemes. In this stuff, we proposed the score arbitration method and composed TLM algorithm. Also we analyze the performance compared with general arbitration methods through simulation. In the future, bus arbitration policy will be developed with the basis of the score arbitration method and improve the performance of bus system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.1
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• pp.57-68
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• 2004

Although variable-length codes (VLCs) increase coding efficiency using the statistical characteristics of the source data, they have catastrophic effects from bit errors in noisy transmission environments. In order to overcome this problem with VLCs, reversible variable-length codes (RVLCS) have recently been proposed owing to their data recovering capability. RVLCS can be divided into two categories: symmetrical and asymmetrical RVLCs. Although the symmetrical RVLC has generally more overheads than the asymmetrical RVLC, it has some advantages of simpler design and more efficient memory usage. However, existing symmetrical RVLCs still have high complexity in their code design and some room for improvement in coding efficiency. In this paper, we propose a new algorithm for constructing a symmetrical RVLC from the optimal Huffman code table. The proposed algorithm has a simpler design process and also demonstrates improved performance in terms of the average codeword length relative to the existing symmetrical RVLC algorithms.

• Journal of Broadcast Engineering
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• v.20 no.6
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• pp.827-836
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• 2015

The purpose of this study is to suggest improvement direction of the delivery system through researching the information accepter' recognition and use about warning delivery system. According to the survey, they listen to civil defence alert broadcasting on mass media more than personal media. The frequency of alert broadcasting is significantly very low and they listen to it below 5 times in a year. Also, nearly one in four people says its siren and contents are indistinct. Alert broadcasting's siren shows less memory retrieval and sorting capability than others and the result shows that they will act based on the broadcasting instead of reacting to prior knowledge in real situations. Finally, the result shows that improving public awareness through education and publicity more than social system buildup is important in civil defence alert system.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.24 no.6
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• pp.623-632
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• 2013

Electromagnetic topology simplifies a complex analysis area in accordance with electromagnetic coupling. And then electromagnetic topology divides the simplified continuous area into sub-areas and analyzes electromagnetic problems at the sub-areas. Therefore electromagnetic topology has a merit to analyze the electromagnetic coupling in large and complex systems, however simplified modeling technique can generate large errors. In this paper, power balance method is used to estimate errors and subdivide junctions in the electromagnetic topology. The method is applied to analyze conducted and radiated electromagnetic coupling in two kinds of cavity models. Improvement of accuracy was accomplished in accordance with junction subdivision. Moreover we could save computation time and memory comparing with FDTD results.

• The Journal of the Korea Contents Association
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• v.5 no.5
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• pp.107-114
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• 2005

The next generation of 3D mobile games market is becoming increasingly active, more as a result of improvement in the CPU speed of hardware phone, embarkation of 3D engines and high memory capacity, In response to this trend, popular 3D games of PS2 (PlayStation2) and popular online games are being launched as mobile games. However, mobile units have different hardware characteristics compared to those of other platforms such as the PC or the game console. Therefore, mobile game versions of the popular PC games face many limitations in many aspects such as in battery capacity, size of display, capacity of the game, and other user interface issues. Among these many limitations, study for allowing low capacity storage of the game is becoming important. In addition, realistic animation of the 3D character on the small screen of the mobile unit is more important than any other matter. The purpose of this study is to find a solution to providing realistic 3D character animation, and for decreasing the storage capacity of character animation for application in 3D mobile games.