• 한국경영과학회지
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• 제25권4호
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• pp.1-14
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• 2000

The methods of sensitivity analysis for linear programming can be classified in two types: sensitivity analysis using an optimal solution, and sensitivity analysis using an approximate optimal solution. As the methods of sensitivity analysis using an optimal solution, there are three sensitivity analysis methods: sensitivity analysis using an optimal basis, positive sensitivity analysis, and optimal partition sensitivity analysis. Since they may provide different characteristic regions under degeneracy, it is not easy to understand and apply the results of the three methods. In this paper, we propose a generalized sensitivity analysis that can integrate the three existing methods of sensitivity analysis. When a right-hand side or a cost coefficient is perturbed, the generalized sensitivity analysis gives different characteristic regions according to the controlling index set that denotes the set of variables allowed to have positive values in optimal solutions to the perturbed problem. We show that the three existing sensitivity analysis methods are special cases of the generalized sensitivity analysis, and present some properties of the generalized sensitivity analysis.

• Management Science and Financial Engineering
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• 제10권2호
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• pp.103-118
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• 2004

$\epsilon$-sensitivity analysis is a kind of methods for performing sensitivity analysis for linear programming. Its main advantage is that it can be directly applied for interior-point methods with a little computation. Although $\epsilon$-sensitivity analysis was proposed several years ago, there have been no studies on its relationship with other sensitivity analysis methods. In this paper, we discuss the relationship between $\epsilon$-sensitivity analysis and sensitivity analysis using an optimal basis. First. we present a property of $\epsilon$-sensitivity analysis, from which we derive a simplified formula for finding the characteristic region of $\epsilon$-sensitivity analysis. Next, using the simplified formula, we examine the relationship between $\epsilon$-sensitivity analysis and sensitivity analysis using optimal basis when an $\epsilon$-optimal solution is sufficiently close to an optimal extreme solution. We show that under primal nondegeneracy or dual non degeneracy of an optimal extreme solution, the characteristic region of $\epsilon$-sensitivity analysis converges to that of sensitivity analysis using an optimal basis. However, for the case of both primal and dual degeneracy, we present an example in which the characteristic region of $\epsilon$-sensitivity analysis is different from that of sensitivity analysis using an optimal basis.

• 한국방사선학회논문지
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• 제12권4호
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• pp.541-547
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• 2018

흉부 디지털 단층합성(chest digital tomosynthesis, CDT) 검사 시 관전압 및 감도(sensitivity) 변화에 의한 선량감소 효과와 정량적 평가로 선량 최적화 조건을 평가하고자 한다. 관전압 125 kV, 135 kV 설정에 따른 sensitivity 200, 320, 400 변화하여 팬텀의 CDT 영상을 획득하였다. 감도와 관전압 변화 따른 선량과 면적선량(DAP)을 평가하였다. 화질평가는 최대신호 대 잡음비(PSNR), 대조도 대 잡음비(CNR), 신호 대 잡음비(SNR)를 image J를 이용하여 분석하였다. 선량은 14~23%, 면적선량은 13~26% 정도 sensitivity 200, 125 kV에 비해 측정치가 낮아졌고, sensitivity 가 높아짐에 따라 감소율 커짐을 알 수 있었다. PSNR은 27dB 이상으로 모두 의미 있는 수치였고, CNR, SNR은 sensitivity가 낮을수록 우수했으나, 항목마다 통계의 유의성은 달랐다. CNR과 SNR 모두 sensitivity 320, 135 kV가 sensitivity 200, 125 kV와 통계적으로 유의하지 않았다(p>0.05). CDT는 감도, 관전압과 디지털 촬영의 장비의 장점인 보정능력을 이용하여 더 작은 선량으로 화질을 유지 시킬 수 있다.

• 산업공학
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• 제7권3호
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• pp.193-199
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• 1994

The purpose of this paper is to develop a method of the sensitivity analysis that can be applicable to a degenerate tree solution of the minimum cost flow problem. First, we introduce two types of sensitivity analysis. A sensitivity analysis of Type 1 is the well known method applicable to a spanning tree solution. However, this method have some difficulties in case of being applied to a degenerate tree solution. So we propose a sensitivity analysis of Type 2 that keeps solutions of upper bounds remaining at upper bounds, those of lower bounds at lower bounds, and those of intermediate values at intermediate values. For the cost coefficient, we present a method that the sensitivity analysis of Type 2 is solved by using the method of a sensitivity analysis of Type 1. Besides we also show that the results of sensitivity analysis of Type 2 are union set of those of Type 1 sensitivity analysis. For the right-hand side constant or the capacity, we present a simple method for the sensitivity analysis of Type 2 which uses arcs with intermediate values.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.149-154
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• 2004

The design sensitivity analysis of Zwicker's loudness with respect to structural sizing design variables is developed. The loudness sensitivity in the critical band is composed of two equations, the derivative of main specific loudness with respect to 1/3-oct band level and global acoustic design sensitivities. The main specific loudness is calculated by using FEM, BEM tools. i.e. MSC/NASTRAN and SYSNOISE. And global acoustic sensitivity is calculated by combining acoustic and structural sensitivity using the chain rule. Structural sensitivity is obtained by using semi-analytical method and acoustic sensitivity is implemented numerically using the boundary element method. For sensitivity calculation, sensitivity analyzer of loudness (SOLO), in-house program is developed. A 1/4 scale car cavity model is optimized to show the effectiveness of the proposed method.

• 대한가정학회지
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• 제44권4호
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• pp.133-144
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• 2006

The contemporary period is called "the age of sensibility" in which each individual consumer seeks to have her or his own products. Businesses are in need of design developments with an emphasis on customer sensitivity, and at the same time consumers must understand their own sensitivity to acquire information on designs that suit them. This research established a sensitivity and configuration database on designing men's jackets using the sensitivity engineering approach to clothing design information. The user interface was created on the Internet. Sixty-seven sensitivity terms of vocabulary appropriate for the assessment of men's jacket design were selected, and the different designs were classified into six items and 24 categories. Thirty men's jackets with different designs were produced for sensory testing and the results were analyzed in accordance with general linear I statistics. A sensitivity database was established for each category. My-sql, PHP, Java Script, and Html were used for the configuration database work. The configuration of items/categories, with the most appropriate sensitivity database information assigned to the selected sensitivity vocabulary, was programmed for display on the computer screen. The sensitivity vocabulary of a customer's choice for each factor was selected for the program to run, while the category and product configuration of the men's jacket most suitable for the search was displayed based on the user interface.

• Human Ecology Research
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• 제56권6호
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• pp.619-626
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• 2018

This study investigated the impact of the amount of time online on cyberbullying perpetration of middle school students as well as examined if the justice sensitivity (victim sensitivity and penetrator sensitivity) moderated the relationship between the amount of time online and cyberbullying perpetration. The participants in this study were 236 students (120 boys and 116 girls) from two middle schools located in Seoul and Incheon. The levels of cyberbullying perpetration and justice sensitivity were measured by scales developed by Campfield (2008) and Schmitt et al. (2010), respectively. The participants were also asked to report on how much time they spent online a day. The data were analyzed via descriptive statistics, hierarchical regression, and procedures mentioned by Baron and Kenny (1986). The results revealed that the more the students used the Internet, the more likely they were to become a cyberbullying perpetrator. However, such a tendency was observed only for the students who had a higher level of victim sensitivity, and not for those with a lower level of victim sensitivity. This suggested that victim sensitivity moderated the effect of the amount of time spent on the Internet on cyberbullying perpetration; but, penetrator sensitivity had no moderating effect.

• 복식문화연구
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• 제15권6호
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• pp.1078-1083
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• 2007

The purpose of this study is to identify the relationships among price sensitivity, brand sensitivity, and fashion innovativeness. The data used in this study were gathered through surveying university students residing in Seoul metropolitan area using convenience sampling method. One hundred thirty eight questionnaires were used in statistical analysis, confirmatory factor analysis and path analysis using structural equation modeling. The results showed that the higher the price sensitivity, the lower the fashion innovativeness and the brand sensitivity.

• Journal of the Korean Society for Industrial and Applied Mathematics
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• 제3권2호
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• pp.161-171
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• 1999

Aerodynamic sensitivity analysis codes are developed via the hand-differentiation using a direct differentiation method and an adjoint method respectively from discrete two-dimensional compressible Navier-Stokes equations. Unlike previous other researches, Baldwin-Lomax algebraic turbulence model is also differentiated by hand to obtain design sensitivities with respect to design variables of interest in turbulent flows. Discrete direct sensitivity equations and adjoint equations are efficiently solved by the same time integration scheme adopted in the flow solver routine. The required memory for the adjoint sensitivity code is greatly reduced at the cost of the computational time by allowing the large banded flux jacobian matrix unassembled. Direct sensitivity code results are found to be exactly coincident with sensitivity derivatives obtained by the finite difference. Adjoint code results of a turbulent flow case show slight deviations from the exact results due to the limitation of the algebraic turbulence model in implementing the adjoint formulation. However, current adjoint sensitivity code yields much more accurate sensitivity derivatives than the adjoint code with the turbulence eddy viscosity being kept constant, which is a usual assumption for the prior researches.

• 전기학회논문지
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• 제63권8호
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• pp.1075-1079
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• 2014

In this paper, we describe the analysis and the compensation method of the g-sensitivity error for MEMS vibratory gyroscopes. Usually, the g-sensitivity error has been ignored in the commercial MEMS gyroscope, but it deserves our attention to apply for the missile application as a tactical grade performance. Thus, it is necessary to compensate for the g-sensitivity error to reach a tactical grade performance. Generally, the g-sensitivity error seems intuitively to be a gyroscope bias error proportional to the linear acceleration. However, we assert that the g-sensitivity error mainly causes not a bias error but a scale-factor error. And we verify that the g-sensitivity scale-factor error occurs due to the non-linearity of parallel plate electrodes. Therefore, we propose the compensation method to remove the g-sensitivity scale-factor error. The experimental result showed that a proposed compensation method improved successfully the performance of the MEMS vibratory gyroscope.