• Structural Engineering and Mechanics
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• 제40권2호
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• pp.245-256
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• 2011

In this paper, the use of universal serendipity elements (USE) to eliminate node mapping distortions for dynamic problem is presented. Rectangular shaped elements for USE are being introduced by using a flexible master element with an adjustable edge node location. The shape functions of the universal serendipity formulation are used to derive the mass and damping matrices for the dynamic analyses. These matrices eliminate the node mapping distortion errors that occurs incase of the standard shape function formulations. The verification of new formulation will be tested and the errors encountered in the standard formulation will be studied for a dynamically loaded deep cantilever.

• 한국구조물진단유지관리공학회 논문집
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• 제3권4호
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• pp.199-204
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• 1999

The continuing development of the sensors for the measurement of the safety of structures has been making a turning point in measuring and evaluating the larger civil structural system as well. However, there are still remaining problems to be solved for the extremely large structure because the natural damages of those structures are not so simple to be monitored for the reason of their locational and structural conditions. One of the most significant problems is that a number of cables which connect the measuring system to the analyzer are liable to distort actual data. This paper presents a new monitoring system for large structures by means of a local wireless communication technique which would eliminate the possibility of the distortion of data by noise in cables. This new monitoring system employs the wireless system and the software for data communication, along with the strain sensor and accelerometers which have been already used in the past. It makes it possible for the data, which have been chosen by the central controling system from the various sensors placed in the large civil structures, to be wirelessly delivered and then analyzed and evaluated by decision making system of the structures.

• 정보과학회 논문지
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• 제41권10호
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• pp.847-858
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• 2014

지금까지 최적의 인간 시각 만족을 위한 이미지 평가 기법 또는 도구 연구가 많이 이루어져 오고 있는데 SSIM(Structural SIMilarity) 및 이의 개선 기법들이 그 대표적인 예이다. 하지만 이들 기법은 여전히 다양한 이미지 종류 및 이미지 왜곡 종류에 대해 견실하게 대응하지 못하는 한계를 보이며 인간 시각 만족과의 괴리가 크게 존재하고 있다. 이 논문에서는 SSIM 및 개선된 SSIM 기법을 대상으로 집중적인 이미지 평가를 수행하였으며 각각의 함수에서의 관측된 이상 동작 내용에 대해서 원인을 분석하고 이를 보완 및 개선하는 새로운 이미지 평가 기법을 제시한다. 또, 기법에 대한 다양한 이미지 평가 실험을 통해서 제안 기법이 SSIM과 이의 기존 개선 기법보다 여러 이미지 종류와 왜곡 종류에 대해서 인간 시각 만족을 견실하고 일관성 있게 효과적으로 표현하고 있음을 보인다.

• 정보과학회 논문지
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• 제42권10호
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• pp.1294-1302
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• 2015

현재까지 인간 시각 체계를 정확하게 반영하기 위한 이미지 평가 기법에 대한 연구가 많이 이루어져 오고 있다. SSIM은 인간의 시각 체계가 이미지의 구조적 정보에 예민하다는 점을 이용하여 구조적 정보를 이용하여 이미지를 평가하는 대표적인 인간 시각 체계를 만족시키는 평가 기법이다. 하지만 SSIM은 이미지의 색 차이를 반영하지 못하는 문제가 있다. 이러한 문제를 해결하기 위해, HSI 색 공간을 활용한 SHSIM 기법이 제안되었으나 두 컬러 이미지 간 인지적 색 차이를 충분히 반영하지는 못하고 있다. 본 논문에서는 CIE Lab 색 공간을 도입하여 대응 되는 픽셀들의 인지적 색 차이를 계산하여 이미지 평가에 활용하는 방법을 제안한다. 그리고 연구를 더 확장하여, SVM 분류기를 활용하여 왜곡 종류에 따라 최적의 평가 수식을 적용하는 최적화 시스템을 제안한다. 제안하는 기법을 평가하기 위해, 이미지 평가분야에서 가장 많이 알려진 LIVE 데이터베이스를 사용하였으며 네 종류의 평가 기준들을 이용하였다. 실험 결과에서는 제안하는 기법이 다른 기법들보다 인간 시각 체계와 더 상관성이 높다는 것을 보여준다.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.41-49
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• 2007

More diversified and strengthened safety regulations require higher safety vehicle with less weight. The structural foam can play a role for restraining section distortion of main body members undergoing bending collapse at vehicle crash. In this study, using structural foam modeling technology, validated in previous work, the bending collapse characteristics were evaluated for two types of circular and actual vehicle body frame sections. With changing the foam filling method, outer panel thickness and section shape, load carrying capability and absorbed energy were observed. The results indicate valuable design strategy for effectively elevating bending collapse performance of body members with foam filled.

• 대한기계학회논문집A
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• 제27권12호
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• pp.2101-2109
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• 2003

Structural shape optimization offers engineers with numerous advantages in designing shapes of structures. However, excessive relocation of nodes often cause distortion of elements and eventually result in degrade of accuracy and even halts of processes. To overcome these problems, an effective method, Selective Element Method(SEM), has been developed. This paper describes the basic concept of SEM and processes to implement into real-world problem. 2-D and 3-D shape optimization problems have been chosen to show the performance of the method. Though some limitations have been found, it was concluded that SEM can be useful in general shape optimization and even in some special cases such as decision of optimal weld line location.

• International Journal of Concrete Structures and Materials
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• 제11권1호
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• pp.45-58
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• 2017

Recent investigations have pointed out that current code provisions specifying that the stiffness of reinforced concrete elements is strength independent, and therefore can be estimated prior to any strength assignment, is incorrect. A strength allocation strategy, suitable for preliminary structural design of medium height wall-frame dual systems, is presented for allocating strength in such buildings and estimating the dependable rigidities. The design process may be implemented by either the approximate continuous approach or the stiffness matrix method. It is based on the concept of the inelastic equivalent single-degree-of-freedom system which, the last few years, has been used to implement the performance based seismic design. The aforesaid strategy may also be used to determine structural configurations of minimum rotation distortion. It is shown that when the location of the modal centre of rigidity, as described in author's recent papers, is within a close distance from the mass axis the torsional response is mitigated. The methodology is illustrated in ten story building configurations, whose torsional response is examined under the ground motion of Kobe 1995, component KJM000.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2003년도 가을 학술발표회 논문집
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• pp.133-144
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• 2003

Generally, diaphragms are installed in the box girder to prevent or decrease the distortion of tile cross section. In engineering practice, diaphragms are spaced in 5m intervals without reasonable basis. ANd the usual diaphragm type is solid-plate type. It is considered to be noneconomical design to the almost design engineers. In this paper, the parametric study was performed to present the design proposal about the diaphragm stiffness and spacing only in tire single cell box girder. For that, the distortional warping normal stress, bending normal stress and transverse bending normal stress were analyzed using finite element program 'SMB' for the accurate structural analysis.

• 한국통신학회논문지
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• 제34권8A호
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• pp.583-591
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• 2009

높은 PAPR을 갖는 직교 주파수 분할 다중 접속 신호는 비선형 왜곡을 발생시키거나, 송신기의 전력 증폭기의 효율을 나쁘게 한다. 그래서 비선형 왜곡을 줄이기 위한 상호 변조 왜곡 저감 기법이 제안되었다. IMD 저감 기법은 비선형 왜곡에 대하여 PAPR 저감 기법보다 비트 오차율 작게 한다. 하지만 IMD 저감 기법의 결정 기준은 주파수 영역에서 이루어지기 때문에 송신기에 FFT가 추가되어 시스템 복잡도가 증가하고, IMD 연산의 복잡한 계산 과정과, 이에 따른 처리시간이 증가하는 문제가 있다. 그러므로 본 논문에서는 이러한 기존의 IMD 저감 기법의 복잡도와 계산량 저감하기 위한 새로운 방식의 IMD 저감 방식을 제안한다. 또한 본 논문에서는 제안된 방식을 PTS 방식의 OFDM 통신 시스템에 적용하여 기존의 기법과 복잡도와 계산량을 비교한다. 제안된 기법은 PAPR처럼 시간영역에서 IMD의 전력량을 계산하므로 송신기에서 시스템의 복잡도와 계산량을 크게 줄일 수 있다. 또한 새로운 기법은 기존 방식과 BER 성능 면에서 차이를 보이지 않는다.

• 패션비즈니스
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• 제25권5호
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• pp.73-87
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• 2021

This study aimed to develop fashion designs by applying the PO (Provocative Operation) method as a 3D virtual clothing program and to derive the PO application method in fashion design. The first T-shirt design was presented as an existing thinking method, and the second design was developed by applying escape, reversal, exaggeration, distortion, and hopeful thinking techniques, which are techniques for 'provocation' of the PO method, to the first design. Thus, 18 T-shirt designs were developed as 3D virtual clothing, with 3 sets of 6 designs, including the 1st and 2nd designs. The method of using the 'provocation' techniques of the PO method in the development of fashion design derived from this was as follows. First, the 'escape' technique was designed in such a way that a part of the detail or structure was deleted, or a part of the structure or expression element of another item was applied. Second, the 'inversion' technique was expressed by inverting the position or shape of a detail or structure up, down, left, and right; fitting the structural detail or reversing the shape; or converting the structure and form. Third, the 'exaggeration' technique exaggerated the size, length, and volume of a structure's form or detail. Fourth, the 'distortion' technique was expressed as a distortion of lines or shapes or a visual distortion using the Trompe l'oeil technique. Fifth, the 'hopeful thinking' technique was developed and expressed from the idea of an hypothetical 'if' it was absurd, irrational, and unrealistic.