• 천문학회지
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• 제37권2호
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• pp.87-90
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• 2004

Spectrophotometry of the night sky over Mount Bohyun is presented for the nearly entire visible wavelengths of $3600{\~}$8600{\AA}$. The data was obtained under moonless clear sky in February 2004 with the 1.8-m telescope and the long slit spectrograph. The sky spectrum shows a number of strong emission lines originated from light pollution, especially due to high pressure sodium lamps. When compared to the night sky of Kitt Peak, our sky continuum is 1 to 2 magnitude brighter at all wavelengths, the worst being around the broad emission region near 6000${\AA}$. The night sky spectrum presented here with almost complete line identifications is a useful reference for arc-independent wavelength calibrations to check the gravity flexure of the spectrograph and the wavelength shift between FeNeArHe arc frames and science frames.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.621-624
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• 1999

This paper describes a distance estimation method of object's motion in soccer image sequence by tracking field features. And we quantitatively evaluate the estimation accuracy We suppose that the input image sequence is taken with a camera on static axis and includes only zooming and panning transformation between frames. Adaptive template matching is adopted for non-rigid object tracking. For background compensation, feature templates selected from reference frame image are matched in following frames and the matched feature point pairs are used in computing Affine motion parameters. A perspective displacement field model is used for estimating the real distance between two position on Input Image. To quantitatively evaluate the accuracy of the estimation, we synthesized a 3 dimensional virtual stadium with graphic tools and experimented on the synthesized 2 dimensional image sequences. The experiment shows that the average of the error between the actual moving distance and the estimated distance is 1.84%.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.155-158
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• 2007

In this paper, we solved the underestimation problem of PSNR, which is caused by repeated frames, by easily synchronizing original and decoded frames using the proposed marks. Also we propose full-reference system which can be applied for measuring the quality of various kinds of video communication systems, e.g. wireless handsets, mobile phones and applications for PC. In addition, we propose a new video quality assessment metric using video communication parameters, i.e. frame rate and delay. According to the experiments, the proposed metric is not only appropriate for real-time video communication systems but also shows better correlation with the subjective video quality assessment than PSNR. The proposed measuring system and metric can be effectively used for measuring and standardizing the video quality of future communications.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.199-202
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• 2003

In this paper, we propose a new 3D coding method for heterogeneous systems over enhanced Access Grid (e-AG) with 3D display using spatio-temporal scalability. The proposed encoder produces four bit-streams: one base layer and enhancement layer l, 2 and 3. The base layer represents a video sequence for left eye with lower spatial resolution. An enhancement layer l provides additional bit-stream needed for reproduction of frames produced in base layer with full resolution. Similarly, the enhancement layer 2 represents a video sequence for right eye with lower spatial resolution and an enhancement layer 3 provides additional bit-stream needed for reproduction of its reference pictures with full resolution. In this system, temporal resolution reduction is obtained by dropping B-frames in the receiver according to network condition. The receiver system can select the spatial and temporal resolution of video sequence with its display condition by properly combining bit-streams.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2012년도 하계학술대회
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• pp.269-270
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• 2012

Features which exhibit scale and rotation invariance, such as SIFT, are notorious for expensive computation time, and often overlooked for real-time tracking scenarios. This paper proposes a descriptorless matching algorithm based on motion vectors between consecutive frames to find the geometrically closest candidate to each tracked reference feature in the database. Descriptor-less matching forgoes expensive SIFT descriptor extraction without loss of matching accuracy and exhibits dramatic speed-up compared to traditional, naive matching based trackers. Descriptor-less SIFT tracking runs in real-time on an Intel dual core machine at an average of 24 frames per second.

• 한국컴퓨터정보학회논문지
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• 제12권1호
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• pp.67-72
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• 2007

본 논문에서는 파노라믹 영상 구축을 위해 투시 투사에서 2차원 표면의 움직임을 더욱더 잘 표현하는 투시모델을 이용하여 구축하는 방안을 제시한다. 투시 모델에서 모션 파라미터는 현재 프레임의 영역과 이전 프레임에서 매칭된 영역 사이의 불일치 측정을 최소화함으로써 얻어진다. 프레임들은 고정된 참조나 시간에 따라 변하는 참조에 의해 동적 파노라믹 영상으로 구축된다. 실험을 통해서 본 논문에서 제시한 파노라믹 영상이 정지 영상이나 전체적인 비디오 보다 효과적으로 비디오의 내용들을 표현해 주고 크기 절감율도 높음을 알 수 있다.

• Earthquakes and Structures
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• 제18권1호
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• pp.27-44
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• 2020

This work presents a comparison of three performance-based seismic design methods (PBSD) as applied to plane steel frames having eccentric braces (EBFs) and buckling restrained braces (BRBFs). The first method uses equivalent modal damping ratios (ξ_k), referring to an equivalent multi-degree-of-freedom (MDOF) linear system, which retains the mass, the elastic stiffness and responds in the same way as the original non-linear MDOF system. The second method employs modal strength reduction factors (${\bar{q}}_k$) resulting from the corresponding modal damping ratios. Contrary to the behavior factors of code based design methods, both ξ_k and ${\bar{q}}_k$ account for the first few modes of significance and incorporate target deformation metrics like inter-storey drift ratio (IDR) and local ductility as well as structural characteristics like structural natural period, and soil types. Explicit empirical expressions of ξ_k and ${\bar{q}}_k$, recently presented by the present authors elsewhere, are also provided here for reasons of completeness and easy reference. The third method, developed here by the authors, is based on a hybrid force/displacement (HFD) seismic design scheme, since it combines the force-base design (FBD) method with the displacement-based design (DBD) method. According to this method, seismic design is accomplished by using a behavior factor (q_h), empirically expressed in terms of the global ductility of the frame, which takes into account both non-structural and structural deformation metrics. These expressions for q_h are obtained through extensive parametric studies involving non-linear dynamic analysis (NLDA) of 98 frames, subjected to 100 far-fault ground motions that correspond to four soil types of Eurocode 8. Furthermore, these factors can be used in conjunction with an elastic acceleration design spectrum for seismic design purposes. Finally, a comparison among the above three seismic design methods and the Eurocode 8 method is conducted with the aid of non-linear dynamic analyses via representative numerical examples, involving plane steel EBFs and BRBFs.

• Computers and Concrete
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• 제32권5호
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• pp.455-464
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• 2023

Seismologists now suggest that the earth has entered an active seismic period; many earthquake-related events are occurring globally. Consequently, numerous casualties, as well as economic losses due to earthquakes, have been reported in recent years. Primarily, significant and colossal damage occurs in reinforced concrete (RC) buildings with masonry infill wall systems, and the construction of these types of structures have increased worldwide. According to a report from the Ministry of Education in the Republic of Korea, many buildings were built with RC frames with masonry infill walls in the Republic of Korea during the 1980s. For years, most structures of this type have been school buildings, and since the Pohang earthquake in 2017, the government of the Republic of Korea has paid close attention to this social event and focused on damage from earthquakes. From a long-term research perspective, damage from structural collapse due to the short column effect has been a major concern, specifically because the RC frame with a masonry infill wall system is the typical form of structure for school buildings. Therefore, the short column effect has recently been a major topic for research. This study compares one RC frame with four different types of RC frames with masonry infill wall systems. Structural damage due to the short column effect is clearly analyzed, as the result of this research is giving in a higher infill wall system produces a greater shear force on the connecting point between the infill wall system and the column. The study is expected to be a useful reference for research on the short column effect in RC frames with masonry infill wall systems.

• 한국산업정보학회논문지
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• 제22권2호
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• pp.27-34
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• 2017

가장 간단한 샘플링을 위한 목적으로 SPL (Smoothed Projected Landweber)기법 기반의 움직임 보상 블록 압축센싱 기법이 모든 센싱 프레임들에 대해 분산 압축 비디오 센싱 기술이 적용되는 효과적인 방안으로 연구되어 오고 있다. 그러나 기존의 움직임 보상 블록기반의 압축센싱 기법은 매우 간단하여 복원된 위너-지브 프레임에서 우수한 화질을 제공하지 못하는 한계점이 있다. 본 논문에서는 기존의 움직임 보상 블록기반의 압축센싱 기법을 이용한 위너-지브 프레임에서 우수한 화질을 제공될 수 있도록 알고리즘을 변형한다. 즉, 제안된 알고리즘은 참조 프레임이 연속적인 프레임들에 있어 시간적 상관관계에 기초해서 적응적으로 선택되도록 하는 방법으로 설계된다. 다양한 실험 결과를 통하여 제안한 알고리즘은 기존의 알고리즘에 비해 우수한 화질을 제공할 수 있음을 확인한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.1028-1034
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• 1989

A method of analysis of the steady-state performance of induction motor with supply voltage controlled by cyclically-triggered inline thyristors is presented. Phase-variable model and asymmetrical components are not used in this analysis. Instead, Fast Fourier Transform technique and the method of multiple reference frames are employed to obtain the constant-speed performance of I.M. easily.