• 한국전산구조공학회논문집
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• 제21권1호
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• pp.1-11
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• 2008

전단빌딩에 발생한 손상 추정에 있어서 대상 구조물의 물성치를 가정하고 이상화한 모델을 이용한 역해석이 필요하다. 강성행렬을 이용하는 고전적인 손상추정 방법에 비해 유연도 행렬을 이용한 손상추정은 구조물의 저차모드를 이용하기 때문에 비교적 정확한 값을 계산할 수 있기 때문에 더 효과적으로 알려져 있다. 이 논문에서는 손상추정을 위한 알고리즘으로 유전자 알고리즘(Genetic Algorithm, GA)을 도입하였고, 구조 응답에서 취득할 수 있는 유연도 행렬을 이용하여 역해석을 통한 손상추정 기법을 소개하고 있다. 제안된 손상추정 기법은 전단빌딩의 강성에 대한 정확한 정보가 없는 상황에서 전단빌딩의 손상으로 인한 실제 강성변화량을 추정하도록 하였다. 더불어 open source code인 OPENSEES를 이용하여 전단빌딩 수치해석을 통해 제안된 손상추정 기법의 효율성을 검증하였다.

• 대한전기학회논문지:시스템및제어부문D
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• 제54권12호
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• pp.723-731
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• 2005

The $4{\times}4$ homogeneous transformation matrix is a compact representation of orientation and position of an object in robotics and computer graphics. A coordinate transformation is accomplished through the successive multiplications of homogeneous matrices, each of which represents the orientation and position of each corresponding link. Thus, for real time control applications in robotics or animation in computer graphics, the fast multiplication of homogeneous matrices is quite demanding. In this paper, a parallel-architecture vector processor is designed for this purpose. The processor has several key features. For the accuracy of computation for real application, the operands of the processors are floating point numbers based on the IEEE Standard 754. For the parallelism and reduction of hardware redundancy, the processor takes column vectors of homogeneous matrices as multiplication unit. To further improve the throughput, the processor structure and its control is based on a pipe-lined structure. Since the designed processor can be used as a special purpose coprocessor in robotics and computer graphics, additionally to special matrix/matrix or matrix/vector multiplication, several other useful instructions for various transformation algorithms are included for wide application of the new design. The suggested instruction set will serve as standard in future processor design for Robotics and Computer Graphics. The design is verified using FPGA implementation. Also a comparative performance improvement of the proposed design is studied compared to a uni-processor approach for possibilities of its real time application.

• 제어로봇시스템학회논문지
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• 제11권6호
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• pp.492-495
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• 2005

This paper deals with the problem of estimating the asymptotic stability region(ASR) of uncertain variable structure systems with bounded control. Using linear matrix inequalities(LMIs) we estimate the ASR and we show the exponential stability of the closed-loop control system in the estimated ASR. We show that our estimate is always better than the estimate of [3].

• 한국지능시스템학회논문지
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• 제22권2호
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• pp.205-211
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• 2012

통계학과 기계학습의 다양한 기법을 이용하여 문서집합을 군집화하기 위해서는 우선 군집화분석에 적합한 데이터구조로 대상 문서집합을 변환해야 한다. 문서군집화를 위한 대표적인 구조가 문서-단어행렬이다. 각 문서에서 발생한 특정단어의 빈도값을 갖는 문서-단어행렬은 상당부분의 빈도값이 0인 희소성문제를 갖는다. 이 문제는 문서군집화의 성능에 직접적인 영향을 주어 군집화결과의 성능감소를 초래한다. 본 논문에서는 문서-단어행렬의 희소성문제를 해결하기 위하여 인자분석을 통한 인자점수를 이용하였다. 즉, 문서-단어행렬을 문서-인자점수행렬로 바꾸어 문서군집화의 입력데이터로 사용하였다. 대표적인 문서군집화 알고리즘인 자기조직화지도에 적용하여 문서-단어행렬과 문서-인자점수행렬에 대한 문서군집화의 결과들을 비교하였다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2004년도 봄 학술발표회 논문집
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• pp.73-80
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• 2004

Mass matrix, elastic stiffness matrix, load correction stiffness matrix by circulatory non-conservative force, and Winkler and Pasternak foundation matrix of framed structure in 2-D are calculated for stability analysis of divergence or flutter system. Then, a matrix equation of the motion for the non-conservative system is formulated and numerical results are presented to demonstrate the effect of some parameters with using Newmark method.

• ETRI Journal
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• 제27권6호
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• pp.788-797
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• 2005

This paper describes the design and realization of an extra high frequency band $8{\times}8$ microstrip Butler matrix. Operation at 36 GHz is achieved with a frequency bandwidth exceeding 400 MHz. The circuit is implemented on a bi-layer microstrip structure using conventional manufacturing processes. This planar implementation of a Butler matrix is a key component of a switched beam smart antenna with printed antenna elements integrated on-board. Conception details, simulation results, and measurements are also given for the components (hybrid couplers, cross-couplers, and vertical inter-connections) used to implement the matrix.

• 대한수학회논문집
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• 제38권1호
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• pp.113-120
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• 2023

In this paper, we investigate the dimension and the structure of the centralizer of a square matrix with entries from an arbitrary field.

• 대한화장품학회지
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• 제22권2호
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• pp.182-192
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• 1996

In this study, the relationship between wax matrix in lipstick and sweating was investigated by observing the change of size and shape of wax matrix with sweating by Scanning Electron Microscopy (SEM). For observation by SEM, a lipstick sample was frozen in liquid nitrogen, then the oil in the lipstick was extracted out in cold isopropanol($-70^{\circ}C$) for 1-3days. After isopropanol was evaporated, the sample was sputtered with gold, and examined by SEM. When examined the sweated sample by SEM, the change of wax matrix underneath the surface from fine, uniform structure to coarse, nonuniform structure was observed, which was resulted from the caking of surrounding wax matrix. That is, the oil underneath the surface was migrated to the surface of lipstick with sweating, consequently the wax matrix at that region was rearranged into the coarse matrix. In case of flamed lipstick, sweating was delayed and the wax matrix was much coarser than that of unflamed one. Its larger wax matrix at surface region was good for including oil. The effect of molding temperature on sweating was also studied. As the molding temperature was increased, sweating was greatly reduced and the size of wax matrix was increased. It was also found that sweating was influenced with the compatinility of wax and oil. A formula consisting of wax and oil which have good compatibility has a tendency of reduced sweating and increased size of wax matrix. When pigment was added to wax and oil. It was also found that sweating was influenced with the passage of time by observing a thick membrane of wax on surface of lipstick after a month from molding. In case of some lipsticks, the size of wax matrix was altered to bigger or smaller. In conclusion, the structure of wax matrix at the surface region of lipstick was changed with the process of foaming, molding temperature, compatibility of wax and oil, addition of pigment, and the passage of time. In most cases, as the size of wax matrix was increased, sweating was reduced and delayed.

• 시스템엔지니어링학술지
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• 제8권1호
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• pp.21-28
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• 2012

Development of the system that has required performance is the most important figure and that is the key of project succeed. In order to perform that, systems engineering has come to the fore as a solution. In each step of system engineering process, particularly, requirement analysis and derivation, logical solution, architecture design step are known to affect many of the function and efficiency. Of these, this paper focus on architecture design. We introduce methodology for physical architecture design by applying DSM(Design Structure Matrix) methodology which is based on result of logical solution from MBSE methodology.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 1998년도 추계학술대회 논문집
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• pp.63-66
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• 1998

In the implementation of the simplex method program, the representation and the maintenance of basis matrix is very important, In the experimental study, we investigates Suhl's idea in the LU factorization and LU update of basis matrix. First, the triangularization of basis matrix is implemented and its efficiency is shown. Second, various technique in the dynamic Markowitz's ordering and threshold pivoting are presented. Third, modified Forrest-Tomlin LU update method exploiting sparsity is presented. Fourth, as a storage scheme of LU factors, Gustavson data structure is explained. Fifth, efficient timing of reinversion is developed. Finally, we show that modified Forrest-Tomlin method with Gustavson data structure is superior more than 30% to the Reid method with linked list data structure.