• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.30 no.2
• /
• pp.83-88
• /
• 2007

본 논문에서 선형함수의 곱의 형태로 표현된 비선형 함수를 목적식 또는 제약식에 가지는 비선형 최적화 문제를 새로운 변수를 추가하여 선형 Relaxation 최적화 문제로 Reformulation 하는 기법을 소개한다. 특히, 선형함수의 곱의 형태를 가지는 비선형 함수를 포함하는 비선형 정수 최적화 문제를 선형 정수 최적화 문제로 Relaxation할 경우 두 최적화 문제의 해가 일치함을 보인다. 또한 소개된 Relaxation 기법을 응용하여, 추가되는 변수의 수를 증가시킴으로서, 보다 Tight한 Relaxation 문제를 도출하는 과정에 대하여 소개한다.

• Proceedings of the Korean Operations and Management Science Society Conference
• /
• 1996.04a
• /
• pp.525-529
• /
• 1996

Decision environments involve a high degree of uncertainty as well as multiple, conflicting goals. Although traditional goal programming offers a means of considering multiple, conflicting goals and arrives at a satisficing solution in a deterministic manner, its major drawback is that decision makers often specify aspiration level of each goal as a single number. To overcome the problem of setting aspiration levels, chance constrained programming can be incorporated into goal programming formulation so that sampling information can be utilized to describe uncertainty distribution. Another drawback of goal programming is that it does not provide a systematic approach to set priorities and trade-offs among conflicting goals. To overcome this weekness, the analytic hierarchy process(AHP) is used in the model. Also, most goal programming models in the literature are of a linear form, although some nonlinear models have been presented. Consideration of risk in technological coefficients and right hand sides, however, leads to nonlinear goal programming models, which require a linear approximation to be solved. In this paper, chance constrained reformulation with linear approximation is presented for a 0-1 goal programming problem whose technological coefficients and right hand sides are stochastic. The model is presented with a numerical example for the purpose of demonstration.

• Journal of the Chungcheong Mathematical Society
• /
• v.7 no.1
• /
• pp.141-152
• /
• 1994

We consider a numerical scheme for solving a nonlinear boundary integral equation (BIE) obtained by reformulation the nonlinear boundary value problem (BVP). We give a simple alternative to the standard collocation method for the nonlinear BIE. This method consists of one conventional linear system and another coupled linear system resulting from an auxiliary BIE which is obtained by differentiating both side of the nonlinear interior integral equations. We obtain an analogue BIE through the perturbation of the fundamental solution of Laplace's equation. We procure the super-convergence of approximate solutions.

• Proceedings of the KIEE Conference
• /
• 2003.07a
• /
• pp.110-112
• /
• 2003

This paper presents an alleviant technique for solving ill-conditioned linear systems using spectral adaptive mapping, which is based on spectral mapping theorem. The conventional approaches to solve the ill-conditioned linear systems are divided into reformulation and alleviant technique. So far, the alleviant technique is evaluated the most effective one. In this paper, an adaptive mapping of spectrum is adopted to alleviate the condition number of ill-conditioned linear systems. A shift constant, which is a dominant factor of the spectral adaptive mapping that are proposed, is assessed by the system spectrum. The proposed spectral adaptive mapping technique is tested to demonstrated the validation on several size Hilbert matrices and small scale power systems, which are provide the promising results.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.8 no.12
• /
• pp.4502-4512
• /
• 2014

This article presents a reformulation of the Grey Edge framework for colour constancy. Colour constancy is the ability of a visual system to perceive objects' colours independently of their scenes' illuminants. Colour constancy algorithms try to estimate the colour of an illuminant from image values. This estimation can later be used to correct the image as though it were taken under a white illuminant. The modification presented allows the framework to incorporate image-specific filters instead of the commonly used edge detectors. A colour constancy algorithm is proposed using PCA and FastICA linear component analyses methods for the construction of such filters. The results show that the proposed method improves the accuracies of the Grey Edge framework algorithms whilst on the other hand, achieving comparable accuracies with the state-of-the-art methods, but improving their time efficiencies.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.11 no.2
• /
• pp.205-213
• /
• 1987

A linear thermoviscoelastic material model, whose basis is on incremental constitutive equation that takes complete strain and temperature histories into account, is derived and computerized in the finite element code. The thermoviscoelastic F.E.M. code which is intended primarily to analyze the cylinder model during the cool-down period, embodies the assumption of linearly elastic bulk and visco-elastic shear responses, thermo-rheologically simple response to temperature change and isotropic thermal expansion. The verification of computer program is accomplished by first testing it against a closed form solution of A.M. Freudenthal & M. Shinozuka's. The stress and strain analyses of five cylindrical models are presented and compared with experimental results. Analytical results are good agreement with experimental results. Margins of safety are evaluated and its allowable ranges are presented.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.17 no.11
• /
• pp.3204-3217
• /
• 2023

In this paper, the downlink of the multicast based spatial modulation systems is investigated. Specifically, physical layer multicasting is introduced to increase the number of access users and to improve the communication rate of the spatial modulation system in which only single radio frequency chain is activated in each transmission. To minimize the bit error rate (BER) of the multicast based spatial modulation system, a joint optimizing algorithm of antenna selection and multicast precoding is proposed. Firstly, the joint optimization is transformed into a mixed-integer non-linear program based on single-stage reformulation. Then, a novel iterative algorithm based on the idea of branch and bound is proposed to obtain the quasioptimal solution. Furthermore, in order to balance the performance and time complexity, a low-complexity deflation algorithm based on the successive convex approximation is proposed which can obtain a sub-optimal solution. Finally, numerical results are showed that the convergence of our proposed iterative algorithm is between 10 and 15 iterations and the signal-to-noise-ratio (SNR) of the iterative algorithm is 1-2dB lower than the exhaustive search based algorithm under the same BER accuracy conditions.