• Title, Summary, Keyword: sensitivity

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Generalized Sensitivity Analysis at a Degenerate Optimal Solution (퇴화최적해에서 일반감도분석)

  • 박찬규;김우제;박순달
    • Journal of the Korean Operations Research and Management Science Society
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    • v.25 no.4
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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.

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On the Relationship between $\varepsilon$-sensitivity Analysis and Sensitivity Analysis using an Optimal Basis

  • Park, Chan-Kyoo;Kim, Woo-Je;Park, Soondal
    • Management Science and Financial Engineering
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    • v.10 no.2
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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.

Optimization of Image Quality according to Sensitivity and Tube Voltage in Chest Digital Tomosynthesis (디지털 흉부단층합성검사에서 감도와 관전압 변화에 따른 영상 최적화)

  • Kim, Sang-Hyun
    • Journal of the Korean Society of Radiology
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    • v.12 no.4
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    • pp.541-547
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    • 2018
  • To evaluate the effect of dose and image quality for Chest Digital Tomosynthesis(CDT) using sensitivity and tube voltage(kV). CDT images of the phantom were acquired varying sensitivity 200, 320, 400 according to set tube voltage of 125 kV and 135 kV. The dose and Dose Area Product(DAP) according to change of sensitivity and kV were evaluated and Image quality was evaluated by PSNR, CNR, SNR using Image J. Dose were lowered 14~23% less than sensitivity 200, 125 kV and DAP were lowered 13~26% less than sensitivity 200, 125 kV. PSNR were over 27 dB, which were significant value and CNR, SNR were better as sensitivity value was lower. But there were different statistical significant to each item. CNR and SNR were not statistically significant at sensitivity 320, 135 kV(P>0.05). CDT can improve image quality with lower radiation dose using better than quality and correction power at digital radiography system.

Sensitivity Analysis on the Degenerate Tree Solution of the Minimum Cost Flow Problem (최소비용문제의 퇴화 정점 최적해에 대한 감도분석)

  • Chung, Ho-Yeon;Park, Soon-Dal
    • IE interfaces
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    • v.7 no.3
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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.

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DESIGN SENSITIVITY ANALYSIS AND OPTIMIZATION OF ZWICKER'S LOUDNESS (Zwicker 라우드니스에 대한 설계 민감도 해석 및 최적화)

  • Kang, Jung-Hwan;Wang, Se-Myung
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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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.

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The Development of a System for Product Search Using a Sensibility and Configuration Database on Designing Men's Jackets (신사복 재킷디자인의 감성 및 형상 데이터베이스를 이용한 제품검색 시스템 개발에 관한 연구)

  • Park, Yun-A
    • Journal of the Korean Home Economics Association
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    • v.44 no.4
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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.

Effect of the Amount of Time Online on Cyberbullying Perpetration in Middle School Students and the Moderating Role of Justice Sensitivity (중학생의 인터넷 사용시간이 사이버불링 가해행동에 미치는 영향과 정의민감성의 조절효과)

  • Park, Ju Hee
    • Family and Environment Research
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    • v.56 no.6
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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.

Exploring the Role of Sensitivity on Fashion Innovativeness (민감성이 패션 혁신성에 미치는 영향)

  • Park, Hye-Jung
    • The Research Journal of the Costume Culture
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    • v.15 no.6
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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.

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AERODYNAMIC SENSITIVITY ANALYSIS FOR NAVIER-STOKES EQUATIONS

  • Kim, Hyoung-Jin;Kim, Chongam;Rho, Oh-Hyun;Lee, Ki Dong
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.3 no.2
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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.

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A Study on the G-Sensitivity Error of MEMS Vibratory Gyroscopes (진동형 MEMS 자이로스코프 G-민감도 오차에 관한 연구)

  • Park, Byung-Su
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.8
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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.