• The Bulletin of The Korean Astronomical Society
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• v.40 no.1
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• pp.82.1-82.1
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• 2015

We investigate the long-term spatial drift of the center and the temporal variation of the shutter delay time map of Y4KCam mounted on the CTIO 1.0m telescope. We have collected shutter delay time maps for over 7 years as a part of long-term survey program. We find that the center of the shutter delay time map can drift up to $450{\mu}m$ on the CCD. This effect can result in a small amount of error unless the proper shutter delay time correction, but it does not appear to cause any significant problems in photometric measurements. We obtain the mean value of the shutter delay time of $69.1{\pm}0.9$ msec and find no temporal variation of the shutter delay time of Y4KCam for over 7 years, indicative of the mechanical stability of the shutter. We suggest that using a master shutter delay time correction frame would be sufficient to achieve high precision photometry and this does not add up errors more than ~ 2.5 mmag across the CCD frame with exposure times longer than 1 sec.

• Journal of Information Processing Systems
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• v.13 no.4
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• pp.818-833
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• 2017

This paper introduces a new algorithm that renders motion blur using triangular motion paths. A triangle occupies a set of pixels when moving from a position in the start of a frame to another position in the end of a frame. This is a motion path of a moving triangle. For a given pixel, we use a motion path of each moving triangle to find a range of time that this moving triangle is visible to the camera. Then, we sort visible time ranges in the depth-time dimensions and use bitwise operations to solve the occlusion problem. Thereafter, we compute an average color of each moving triangle based on its visible time range. Finally, we accumulate an average color of each moving triangle in the front-to-back order to produce the final pixel color. Thus, our algorithm performs shading after the visibility test and renders motion blur in real time.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.10a
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• pp.348-355
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• 2000

The characteristics on non linear behavior and the failure mechanism of RC space frame structure serving railway under seismic action have been investigated by numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and RC frame elements with fibers are employed. Fibers are characterized as RC one and PL one to distinguish different energy release after cracking. Due to deviation of mass center and stiffness center of entire structure the complex behavior under seismic action is shown. The excessive shear force is concentrated on the pier beside flexible one relatively, which leads to failure of bridge concerned.

• Proceedings of the IEEK Conference
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• 1999.06a
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• pp.1075-1078
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• 1999

In this paper, we propose a hybrid watermarking algorithm for MPEG bitstream. Hybrid watermarking technique uses Spread Spectrum technique for I-frame and Motion Vector technique for P, B-frame. Thus, it enables all MPEG frame to be watermarked. By applying above technique, it is possible not only to protect intellectual property right but also to be robust to all kinds of attacks. And this scheme requires partial decoding of MPEG bitstream, so it can be applied to real time watermarking applications.

• Journal of Satellite, Information and Communications
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• v.7 no.3
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• pp.145-148
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• 2012

In applying LCD to TV application, one of the most significant factors to be improved is image sticking on the moving picture. LCD is different from CRT in the sense that it's continuous passive device, which holds images in entire frame period, while impulse type device generate image in very short time. To reduce image sticking problem related to hold typedisplay mode, we made an experiment to drive TN-LCD like CRT. We made articulate images by turn on-off backlight, and we realized the ratio of Back Light on-off time by counting between on time and off time for video signal input during 1 frame (16.7ms). Conventional CCFL (cold cathode fluorescent lamp) cannot follow fast on-off speed, so we evaluated new fluorescent substances of light source to improve residual light characteristic of CCFL. We realized articulate image generation similar to CRT by CCFL blinking drive and TN-LCD overdriving. As a result, reduced image sticking phenomenon was validated by naked eye and response time measurement.

• Journal of Science and Technology Studies
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• v.12 no.1
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• pp.79-106
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• 2012

The paper discusses the issue of reality related to interaction between users and electronic figures that mediate by online game system. MMORPG(Massively Multiple Online Role Playing Game) has been known as virtual world that physically and electronically interconnect users and mechanical elements over huge area. Already game items have became a kind of reality for some users long time ago. How these figures could have been regarded as realities? It suggests to take place the temporality of practice around game world. Tremendous practices of human and machines produce their relations and these relations are reinforced self-referentialy. They could constitute their time-space frame that be situated a figure as the something in it.

• Coupled systems mechanics
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• v.9 no.4
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• pp.311-323
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• 2020

This paper deals with the effect of the mode shapes on the dynamic response of a multi-storey frame subjected to moving train loads which are modelled as loads of constant intervals with constant velocity using the finite element method. The multi-storey frame is modelled as a number of Bernoulli-Euler beam elements. First, the first few modes of the multi-storey frame are determined. Then, the effects of force span length to beam length ratio and velocity on dynamic magnification factor (DMF) are evaluated via 3D velocity-force span length to beam length ratio-DMF graphics and its 2D projections. By using 3D and 2D graphics, the directions of critical speeds that force the structure under resonance conditions are determined. Last, the mode shapes related to these directions are determined by the time history and frequency response graphs. This study has been limited by the vibration of the frame in the vertical direction.

• Proceedings of the Acoustical Society of Korea Conference
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• 1993.06a
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• pp.229-232
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• 1993

이 논문은 최근에 개발된 실시간 음성부 검출 알고리즘[1]을 TMS320C30 System board와 IBM PC486을 이용한 implementation에 관한 논문이다. 음성부 검출 알고리즘은 Energy와 LCR(Level Crossing Rate)를 이용하여 각 frame을 음성/묵음으로 분류하는 방법을 사용하였고 DSP 보드를 사용하여 한 frame이 입력되면 다음 frame이 입력되기 전에 그 frame에 대한 음성/묵음 분류를 하여 음성입력이 끝남과 동시에 음성이라고 판단되는 부분만을 DPS moemory상에 저장하므로 불필요한 memory의 낭비를 중이고 다음 단계의 음성처리를 위한 시간을 절약하였다. 이 알고리즘의 성능 평가를 위하여 Rabiner와 Sambur의 알고리즘과 한민수의 알고리즘과를 전문가가 수작업으로 찾아낸 결과와 비교 평가하였다. 알고리즘의 오차는 평균 남성 4.925ms, 여성 5.85ms로 1 frame 이내의 오차를 보였다.

• IEIE Transactions on Smart Processing and Computing
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• v.6 no.2
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• pp.93-101
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• 2017

This paper proposes an algorithm for adaptive loop filter (ALF) complexity reduction in the decoding process. In the original ALF algorithm, filtering for I frames is performed in the frame unit, and thus, all of the pixels in a frame are filtered if the current frame is an I frame. The proposed algorithm is designed on top of the local gradient calculation. On both the encoder side and the decoder side, homogeneous areas are checked and skipped in the filtering process, and the filter coefficient calculation is only performed in the inhomogeneous areas. The proposed algorithm is implemented in Joint Exploration Model (JEM) version 3.0 future video coding reference software. The proposed algorithm is applied for frame-level filtering and intra configuration. Compared with the JEM 3.0 anchor, the proposed algorithm has 0.31%, 0.76% and 0.73% bit rate loss for luma (Y) and chroma (U and V), respectively, with about an 8% decrease in decoding time.

• Structural Engineering and Mechanics
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• v.28 no.5
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• pp.571-585
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• 2008

The purpose of this study is to investigate the linear earthquake behavior of the frame structures including subsoil with different stiffening members and to compare the results of each frame considered. These comparisons are made separately for displacement, bending moments and axial forces for frames with different storey and bay numbers for the time history and the modal analyses. The results of both methods are also compared. The results of the frames with subsoil are also compared with the results of the frames without subsoil. It is concluded that all stiffening members considered in this study decrease the lateral displacement of the frame and the bending moment of the columns and increase the axial force in the columns and that configuration of the bracing members come out to be an important parameter in braced frames since the frames with the same type of bracing give different results depending on configuration. It is also concluded that, in general, the absolute maximum displacements of the frames modeled with subsoil are larger than those of the frames modeled without subsoil.