• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.561-570
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• 2008

The primary object of the paper is to identify the compression forces and inelastic failure behavior using steel plate-concrete structures. The compression tests were carried out for the three types of B/tratios by 25, 33 and 50. The tests proved that the compressive strength of the SC structures can be estimated by the summation of strengths both of the steel plate and concrete. The buckling of the steel plates had been occurring at the plates between studs. The empirical estimation of compressive strength for unstiffened SC structures under compressive loadings was suggested. The buckling behavior was also compared with the results of the finite element analysis.

• Journal of Korean Society of Steel Construction
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• v.20 no.4
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• pp.549-559
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• 2008

The objective of this paper is to identify the compression forces and inelastic failure mode using stiffened steel plate-concrete structures. The compression tests were carried out for the three types of B/t ratios by 25, 33 and 50. The test results proved that the compressive strength of the stiffened SC structures can be estimated by the summation of the strengths both stiffened steel plate and concrete. The buckling of the steel plates had been occurred at the plates between studs. The empirical estimation of compressive strength for the stiffened SC structures under compressive loadings was suggested. The buckling behavior also compared with the results of the finite element analysis. The good agreement has been achieved between the experimental results and finite element results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.89-98
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• 2012

This study estimates the performance of steel spirals according to the compressive strength of the concrete. A total of 24 confined concrete cylinders ($150{\times}300mm$) were cast and tested under monotonic concentric compression. The main test parameters were the yield strength of spiral reinforcements and the compressive strength of the concrete. To effectively evaluate the confinement effect according to the yield strength of steel spirals, the external diameter of steel spirals was designed to be same as the diameter of specimen. The experimental results indicated that the performance of confinement of steel spirals increased as the yield strength of spiral reinforcement increased and the compressive strength of the concrete decreased. Furthermore, existing analytical models were used for predicting the stress versus axial strain relationships of specimens tested in this study. It can be concluded that the accuracy of the analytical models deteriorated as the yield strength of steel spirals and the compressive strength of the concrete increased.

• Journal of Internet Computing and Services
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• v.21 no.4
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• pp.43-49
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• 2020

This paper proposes a lossless image compression method based on arithmetic coding using block-adaptive Context Tree Weighting. The CTW method predicts and compresses the input data bit by bit. Also, it can achieve a desirable coding distribution for tree sources with an unknown model and unknown parameters. This paper suggests the method to enhance the compression rate about image data, especially aerial and satellite images that require lossless compression. The value of aerial and satellite images is significant. Also, the size of their images is huger than common images. But, existed methods have difficulties to compress these data. For these reasons, this paper shows the experiment to prove a higher compression rate when using the CTW method with divided images than when using the same method with non-divided images. The experimental results indicate that the proposed method is more effective when compressing the divided images.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10c
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• pp.452-454
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• 1998

본 논문에서는 MPEG 압축 비디오 상에서 얼굴 영역을 추출하고 이를 인식하는 방법에 대하여 제안한다. 제안된 방법은 크게 MPEG 압축 비디오의 처리를 위한 축소된 DC 영상의 구성 단계, 축소된 DC 영상에서의 얼굴 영역 추출 단계, 그리고 얼굴 영역이 추출된 프레임에 대한 압축 복원 및 얼굴 인식의 3단계로 구성되어있다. DC 영상의 구성 단계에서는 압축 복원 없이 DCT 계수의 DC 값과 2개의 AC 값만을 사용하여 부분적인 2차원 역 DCT 변환을 이용한 방법을 사용하였으며, 얼굴 영역 추출 단계에서는 DC 영상에 대해 얼굴의 색상 및 형태 정보를 이용한 얼굴 후보 영역 추출 방법과 K-L 변환 및 역 변환의 오차에 의한 얼굴 영역 추출 방법을 사용하였다. 얼굴 인식 단계에서는 얼굴 영역이 추출된 프레임에 대하여 GOP 단위의 압축 복원을 수행한 후 고유 얼굴 영상을 이용한 방법으로 얼굴 인식을 수행하였다. 제안된 방법의 성능을 검증하기 위하여 뉴스와 드라마 MPEG 비디오를 대상으로 실험을 수행하였으며, 실험 결과 제안된 방법이 효율적임을 알 수 있었다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.613-616
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• 2010

본 논문에서는 라인파이프 강관의 압축-휨 좌굴 성능 평가 기법을 개발하기 위해 비선형 유한요소해석을 사용하였다. 고강도 강재의 연성거동을 모사하기 위해 범용 유한요소해석 프로그램인 ABAQUS의 사용자 재료모델을 사용하여 GTN(Gurson-Tvergaad-Needleman) 모델을 작성하였다. 실험결과와의 비교를 통해 재료모델상수를 결정하였으며 압축-휨 좌굴 실험의 모사에 사용하였다. 압축-휨 좌굴 성능 평가는 비선형 유한요소해석의 결과로부터 얻어진 한계압축변형률과 최대휨모멘트를 기준으로 수행될 수 있다. 개발된 성능 평가 기법은 고강도 강재를 이용한 라인파이프의 설계 시 대변형 거동 분석에 유용하게 사용될 수 있다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2020.11a
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• pp.129-132
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• 2020

최근 모바일 기기에서 딥러닝 모델을 사용하기 위한 경량화 연구가 진행되고 있다. 그중 모델의 가중치 표현 bit를 줄이는 양자화와 사용하기 위한 다양한 압축 알고리즘이 개발되었다. 하지만 대부분의 양자화 및 압축 알고리즘들은 한 번 이상의 Fine-tuning을 거쳐야 하는데 이 과정은 모바일 환경에서 수행하기에는 연산복잡도가 너무 높다. 따라서 본 논문은 양자화된 가중치를 High Efficiency Video Coding(HEVC)을 통해 압축하는 방법을 제안하고 정확도와 압축률을 실험한다. 실험결과는 양자화만 실시한 경우 대비 크기는 25%의 감소했지만, 정확도는 0.7% 감소했다. 따라서 이런 결과는 모바일 기기에 가중치를 전송하는 과정에 적용될 수 있다.

• Magazine of the Korea Concrete Institute
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• v.7 no.2
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• pp.146-154
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• 1995

I n this paper, an experimental research was carried out to investigate the confinement effect of spiral reinforcements in concrete column specimens subjected to t.he concentric axial corn pressive loads. Main variables were the compressive strengths of concrete of 27.2, 62.4 and 81.2 MPa, and the spacings of spirals of 120, 60, 40, 30, 25 and 20mm. and the yield strengths of spir als of 451 and 1375MPa, respectively. For the same volumetric ratio and yield strength of spir als, it was shown that the strength increment of confined concrete was almost same regardless of the strength of unconfined concrete, however, the axial stram at maximum stress was decreas ed with increasing of the compressive strength of unconfined concrete.

• Polymer(Korea)
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• v.38 no.2
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• pp.193-198
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• 2014

Lens and DVD require high quality of optical property. Conventional injection molded products contain high residual stress and this invokes birefringence since high cavity pressure and high temperature variation are involved in a molding process. Thus these products are often molded by injection compression molding in order to minimize the residual stress through reducing cavity pressure and uniform cavity pressure. In this study, molding parameters affecting molding quality such as property uniformity in injection compression molding were investigated through experiment. Molding quality deviations among the cavities in multi-cavity mold were also studied. Transparent resins, PC and PS were used in this study. Compression gap, compression speed, compression force, and compression delay time for processing variables in injection compression molding were applied in experiment. Compression force, compression delay time, and compression gap significantly affected the optical property of product. The degree of influence of process variable on the product quality was different in different resins. This implies that the optimal operational conditions in injection compression molding existed for each resin according to flow property.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.13-17
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• 1991

고반복 레이저의 여기전원에 적합한 3단의 자기펄스 압축 시스템을 제작하고, 시스템의 특성을 고찰하였다. 자기 펄스 압축 시스템의 특성 파라메타는 펄스 변압기의 출력과 펄스파형에 대한 포화 인덕터의 단면적, 코일의 권수가 고려되었다. 실험 결과 3단의 자기 펄스압축 시스템의 최적 조건에서 펄스 압축비와 전류 이득은 각각 22,20 이었다.