• Proceedings of the Korean Operations and Management Science Society Conference
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• 1995.04a
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• pp.646-655
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• 1995

본 연구에서는 기저역행렬의 계산방법에 따른 효율적인 자료구조를 실험적으로 검토하고, 입력자료방식과 효율화 방법을 제안하여 구현하였다. 기저역행렬의 계산방법에 따른 효율적인 자료구조는 명시형에서는 연결리스트 방식이 유리하였으며, 상하분해형에서는 연결 리스트 방법과 Gustavson 방법이 비슷한 효율을 보였다. 새로운 비영요소의 도입이 많은 경우일수록 연결 리스트가 효율적인 자료구조인 것으로 분석된다. 그리고 MPS자료의 입력방식과 효율화 방안에서는 각 열별로 행 정렬을 실시하고 해싱(hashing)함수를 도입하여 효율화를 기하였다.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1998.10a
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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.

• Journal of Mechanical Science and Technology
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• v.17 no.12
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• pp.1922-1927
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• 2003

Nonlinear normal mode (NNM) vibration, in a nonlinear dual mass Hamiltonian system, which has 6$\^$th/ order homogeneous polynomial as a nonlinear term, is studied in this paper. The existence, bifurcation, and the orbital stability of periodic motions are to be studied in the phase space. In order to find the analytic expression of the invariant curves in the Poincare Map, which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space, Whittaker's Adelphic Integral, instead of the direct integration of the equations of motion or the Birkhoff-Gustavson (B-G) canonical transformation, is derived for small value of energy. It is revealed that the integral of motion by Adelphic Integral is essentially consistent with the one obtained from the B-G transformation method. The resulting expression of the invariant curves can be used for analyzing the behavior of NNM vibration in the Poincare Map.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.799-804
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• 2001

Nonlinear normal mode (NNM) vibration, in a nonlinear dual mass Hamiltonian system, which has 6th order homogeneous polynomial as a nonlinear term, is studied in this paper. The existence, bifurcation, and the orbital stability of periodic motions are to be studied in the phase space. In order to find the analytic expression of the invariant curves in the Poincare Map, which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space, Whittaker's Adelphic Integral, instead of the direct integration of the equations of motion or the Birkhotf-Gustavson (B-G) canonical transformation, is derived for small value of energy. It is revealed that the integral of motion by Adelphic Integral is essentially consistent with the one obtained from the B-G transformation method. The resulting expression of the invariant curves can be used for analyzing the behavior of NNM vibration in the Poincare Map.

• Journal of KSNVE
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• v.9 no.1
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• pp.196-205
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• 1999

The existence. bifurcation. and the orbital stability of periodic motions, which is called nonlinear normal mode, in a nonlinear dual mass Hamiltonian system. which has 6th order homogeneous polynomial as a nonlinear term. are studied in this paper. By direct integration of the equations of motion. Poincare Map. which is a mapping of a phase trajectory onto 2 dimensional surface in 4 dimensional phase space. is obtained. And via the Birkhoff-Gustavson canonical transformation, the analytic expression of the invariant curves in the Poincare Map is derived for small value of energy. It is found that the nonlinear system. which is considered in this paper. has 2 or 4 nonlinear normal modes depending on the value of nonlinear parameter. The Poincare Map clearly shows that the bifurcation modes are stable while the mode from which they bifurcated out changes from stable to unstable.

• Korean Management Science Review
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• v.15 no.1
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• pp.49-62
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• 1998

The purpose of this paper is to develope a large-scale simplex method program LPAKO. Various up-to-date techniques are argued and implemented. In LPAKO, basis matrices are stored in a LU factorized form, and Reid's method is used to update LU maintaining high sparsity and numerical stability, and further Markowitz's ordering is used in factorizing a basis matrix into a sparse LU form. As the data structures of basis matrix, Gustavson's data structure and row-column linked list structure are considered. The various criteria for reinversion are also discussed. The dynamic steepest-edge simplex algorithm is used for selection of an entering variable, and a new variation of the MINOS' perturbation technique is suggested for the resolution of degeneracy. Many preprocessing and scaling techniques are implemented. In addition, a new, effective initial basis construction method are suggested, and the criteria for optimality and infeasibility are suggested respectively. Finally, LPAKO is compared with MINOS by test results.

• IE interfaces
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• v.11 no.2
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• pp.149-157
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• 1998

In this paper, various techniques considering the characteristics of computer memory management are suggested, which can be used in the implementation of simplex method. First, reduction technique of indirect addressing, redundant references of memory, and scatter/gather technique are implemented, and the effectiveness of the techniques is shown. Loop-unrolling technique, which exploits the arithmetic operation mechanism of computer, is also implemented. Second, a subroutine frequently called is written in low-level language, and the effectiveness is proved by experimental results. Third, row-column linked list and Gustavson's data structure are compared as the data structure for the large sparse matrix in LU form. Last, buffering technique and memory-mapped file which can be used in reading large data file are implemented and the effectiveness is shown.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.8
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• pp.3068-3085
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• 2021

The economics of big data knowledge, especially cloud computing and statistical data of consumer preferences, has attracted increasing academic and industry practitioners' attention. Firms nowadays require purchasing not only external private patent knowledge from other firms, but also proprietary big data knowledge to support their new product development. Extant research investigates pricing strategies of external private patent knowledge and proprietary big data knowledge separately. Yet, a comprehensive investigation of pricing strategies of these two types of knowledge is in pressing need. This research constructs an overarching pricing model of external private patent knowledge and proprietary big data knowledge through the lens of firm profitability as a knowledge transaction recipient. The proposed model can help those firms who purchase external knowledge choose the optimal knowledge structure and pricing strategies of two types of knowledge, and provide theoretical and methodological guidance for knowledge transaction recipient firms to negotiate with knowledge providers.

• Journal of Fashion Business
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• v.2 no.1
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• pp.1-11
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• 1998

In this study fashion illustrations published in American Vogue from 1960 to 1989 were investigated. Among the large number of illustrations published in American Vogue in this period a considerable number of illustrations was chosen: from 1960 to 1969 143 editorial illustrations and 333 advertisement illustrations; from 1970 to 1979 34 editorial illustrations and 168 advertisement illustrations; from 1980 to 1989 123 editorial illustrations and 81 advertisement illustrations. In studying those illustrations the main point was put in finding characteristics and the changing trend of fashion Illustrations. In the sixties editorial fashion illustrations were published mainly during early sixties. The Illustrations of Rene Bouch, Evelyn Marcil, Dagmar and Eunice Moore Sloane took the space of editorials. Among those Illustrators Bouch published most frequently. The companies such as Galey & Lord, Lord & Taylor, Bergdorf Goodman, Bonwit Teller etc. used fashion illustrations for the advertisement. The name Kenneth Paul Block, Babara Pearlman and Dorothy Hood can be found very frequently on the illustrations for those companies. Antonio Lopez too published in 1963 some advertisement illustrations. In the seventies the total number of editorial fashion illustrations diminished drastically compared to the number in the sixties. Antonio published in 1973 and 74 fifteen illustrations, Joe Eula published from 1976 to 79 thirteen illustrations, and beside them Mats Gustavson published in 1978 six illustrations. The number of advertisement illustrations decreased a little, but many companies used fashion illustrations for the advertisement. The illustrator who worked most actively were Block and Fred Greenhill. In the eighties editorial illustrations experienced a "Renaissance". New high-level illustrators appeared and new fashion illustration magazines were found. Antonio played a central role among illustrators published for editorials in Vogue. In addition to him 15 other illustrators including Mats and Eula with various styles worked for editorials. In contrast to the flourishment of editorial illustrations the number of advertisement illustrations decreased compared to seventies as a result of the domination of fashion photography in this area. Today only few fashion illustrations can be found in fashion magazines. The magazines are dominated by fashion photographs. However fashion illustrations will not totally perish from fashion magazines, because it still has some valuable functions in fashion advertisement. Those functions cannot be fulfilled by photography. Therefore fashion illustration will survive in fashion magazine but playa minor role compared to photography.