• Journal of the Korean Society for information Management
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• v.25 no.4
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• pp.131-148
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• 2008

The purposes of the study are to design a key-frame extraction algorithm for constructing the virtual storyboard surrogates and to evaluate the efficiency of the proposed algorithm. To do this, first, the theoretical framework was built by conducting two tasks. One is to investigate the previous studies on relevance and image recognition and classification. Second is to conduct an experiment in order to identify their frames recognition pattern of 20 participants. As a result, the key-frame extraction algorithm was constructed. Then the efficiency of proposed algorithm(hybrid method) was evaluated by conducting an experiment using 42 participants. In the experiment, the proposed algorithm was compared to the random method where key-frames were extracted simply at an interval of few seconds(or minutes) in terms of accuracy in summarizing or indexing a video. Finally, ways to utilize the proposed algorithm in digital libraries and Internet environment were suggested.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.8
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• pp.1199-1203
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• 2012

H.264 adopted many compression tools to increase image data compression efficiency such as B frame bi-directional predictions, the direct mode coding and so on. Despite its high compression efficiency, H.264 can suffer from its long coding time due to the complicated tools of H.264. To realize a high performance H.264, several fast algorithms were proposed. One of them is adaptive fast direct mode decision algorithm using mode and Lagrangian cost prediction for B frame in H.264/AVC (MLP) algorithm which can determine the direct coding mode for macroblocks without a complex mode decision process. However, in this algorithm, macroblocks not satisfying the conditions of the MLP algorithm are required to process the complex mode decision calculation, yet suffering a long coding time. To overcome the problem, this paper proposes a fast direct mode prediction algorithm. Simulation results show that the proposed algorithm can determine the direct mode coding without a complex mode decision process for 42% more macroblocks and, this algorithm can reduce coding time by up to 23%, compared with Jin's algorithm. This enables to encode B frames fast with a less quality degradation.

• Smart Structures and Systems
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• v.16 no.1
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• pp.1-26
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• 2015

Minimizing construction cost and reducing seismic damage are two conflicting objectives in the design of any new structure. In the present work, we try to develop a framework in order to solve the optimum performance-based design problem considering the construction cost and the seismic damage of steel moment-frame structures. The Park-Ang damage index is selected as the seismic damage measure because it is one of the most realistic measures of structural damage. The non-dominated sorting genetic algorithm (NSGA-II) is employed as the optimization algorithm to search the Pareto optimal solutions. To improve the time efficiency of the proposed framework, three simplifying strategies are adopted: first, simplified nonlinear modeling investigating minimum level of structural modeling sophistication; second, fitness approximation decreasing the number of fitness function evaluations; third, wavelet decomposition of earthquake record decreasing the number of acceleration points involved in time-history loading. The constraints of the optimization problem are considered in accordance with Federal Emergency Management Agency's (FEMA) recommended seismic design specifications. The results from numerical application of the proposed framework demonstrate the efficiency of the framework in solving the present multi-objective optimization problem.

• Composites Research
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• v.34 no.6
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• pp.400-405
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• 2021

In this study, a composite material frame was designed to increase the energy harvesting efficiency of polyvinylidene fluoride (PVDF) ribbon harvesters which are installed inside smart shoes. In order to minimize the amount of deformation in the load direction of the frame, it was designed using carbon continuous fiber composites and its complex shaped structure was manufactured using a 3D printer. In order to calculate the amount of deformation of the insole and midsole of the shoes under the condition of the load generated during walking, the insole and midsole were modeled using the distributed spring elements. Using finite element analysis, the elongation of ribbon-type harvesters mounted on smart shoes was calculated during walking. It is expected that the predicted elongation of the harvester can be utilized to increase the energy harvesting efficiency of smart shoes.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.425-428
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• 1999

Turbo decoder were shown to achieve performance within 0.7㏈ of the Shannon capacity limit. This constituted a significant gain in power efficiency over other coding techniques known at the time. In this paper, Turbo code with constraint length K＝4, code rate 1/3, frame size 196bits(6 tail bits), 20㎳ frame and 6bit MAP decoder is implemented using VHDL. The designed Turbo code is used for voice service. Interactions of the system are used to attain large performance improvements.

• Broadcasting and Media Magazine
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• v.18 no.2
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• pp.92-99
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• 2013

기존의 Full HD보다 4배 이상 많은 화소를 한 화면에 담은 고품질의 디스플레이 장치가 출시되었고, 고해상도의 영상을 실어 보낼 수 있는 차세대 압축 기술인 HEVC(High Efficiency Video Coding)가 표준화 승인을 받았다. 또한 최근 고품질의 콘텐츠를 위해 영화에서는 프레임 레이트(frame rate) 변화가 일어나고 있으며, 디스플레이 환경 또한 하이 프레임 레이트(high frame rate, HFR)가 지원되고 있는 추세이다. 가정에서도 영화관 수준의 콘텐츠를 볼 수 있는 환경의 변화가 생겼음을 고려하였을 때, 해상도와 함께 프레임 레이트에 대한 연구가 필요하다. 따라서 본 기고에서는 UHD(Ultra High Definition)와 HFR의 의미, 그리고 고품질의 콘텐츠 제작 프로세스의 변화에 대해 알아본다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1992.10a
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• pp.52-57
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• 1992

The purpose of this study is that to develop computer program, which is about to analy size nonlinear behaviour of elastic framed structures include to geometric & material nonlineality, and to formulate between stress-strain relationship. In order to examplity the efficiency of this program, a few analytical results have been obtained on : (1) nonlinear behaviour of beam which is subject to vertical force (2) nonlinear behaviour of portal frame which is subject to vertical & horizontal force.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2001.05a
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• pp.57-60
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• 2001

In this paper, we propose growing algorithm of wavelet neural network. It is growing algorithm that adds hidden nodes using wavelet frame which approximately supports orthogonality in wavelet neural network based on wavelet theory. The result of this processing can be reduced global error and progresses performance efficiency of wavelet neural network. We apply the proposed algorithm to approximation problem and evaluate effectiveness of proposed algorithm.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.1041-1046
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• 1989

In this paper, we attempt to control induction motors with high power efficiency as well as high dynamic performance by utilizing the recently developed theories: singular perturbation technique and noninteracting feedback control. Our controller does not need the transformation between a d-q synchronously rotating frame and a x-y stator-fixed frame. It is computationally quite simple. Furthermore, it does not depend on the rotor resistance. To illuminate the practical significance of our results, we present simulation and experimental results as well as mathematical performance analysis.

• International Journal of Fluid Machinery and Systems
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• v.2 no.2
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• pp.136-146
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• 2009

Small axial fans have become widely used as cooling devices in recent years. Because of their increasing importance, studies have been conducted on ways to improve the performance and reduce the noise of such fans. In this report, a small axial fan with a diameter of 85 mm (a type popularity used in personal computer or workstation) was selected for further examination. The influence on aerodynamic performance and noise of such frame design parameters as blade tip clearance results in a decrease of discrete frequency noise and an increase of broad-spectrum noise. As for the most suitable design refinement in terms of fan efficiency, we found that the treatment of outlet corner roundness and altering spoke skew to the direction counter to that of fan rotation was effective.