• 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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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.

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.

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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Factors Influencing Cultural Sensitivity among Nursing Students (간호대학생의 문화적 민감성에 영향을 미치는 요인)

  • Oh, Won-Oak
    • Child Health Nursing Research
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    • v.17 no.4
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    • pp.222-229
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    • 2011
  • Purpose: This study was conducted to determine the predictors of cultural sensitivity for nursing students in Korea. Methods: The participants in this study were 332 nursing students. Data collection was conducted through the use of questionnaires which were constructed to include a Cultural Sensitivity Scale, Knowledge of Culture, Interpersonal Reaction Index, and Self-efficacy Scale. Results: Results showed that cultural sensitivity of nursing students was middle range. Knowledge level of culture was very low. There was a significant positive correlation between cultural sensitivity and knowledge of culture, empathy, and self-efficacy. The significant factors influencing cultural sensitivity of nursing students were empathy, self-efficacy, experience of an overseas trip and awareness of cultural education. These four factors explained 23.8% of the variance in cultural sensitivity of nursing students. Conclusion: These results indicate that cultural sensitivity is an important link with empathy and self-efficacy in nursing students. For nursing students to enhance cultural sensitivity, a transcultural nursing curriculum needs to develop for appropriate and effective services in cross-cultural situations of the multicultural families in Korea.

Brand Sensitivity and Public Self-Consciousness among Fashion Consumers (패션 소비자들의 브랜드 민감성과 공적 자기의식에 관한 연구)

  • Lee, Seung-Hee
    • Journal of Fashion Business
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    • v.14 no.4
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    • pp.102-110
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    • 2010
  • The purposes of this study were to examine the relationship between brand sensitivity and public self-consciousness, and the effects of gender and age on brand sensitivity and public self-consciousness. The subject used for this study were three hundred and thirty-five college students (118 male students and 217 female students). For data analysis, descriptive statistics, Cronbach's alpha, multiple regression, and t-test were used. As the results, first, there were the significant differences between male students and female students on brand sensitivity and public self-consciousness. Female students had higher scores on brand sensitivity and public self-consciousness than male students as expected. Second, there were the significant differences between younger college students and older college students on brand sensitivity and public self-consciousness. Older college students had higher scores on brand sensitivity and public self-consciousness than younger college students. Finally, public self-consciousness influenced on brand sensitivity the most significantly, followed by age variable. Based on these results, brand management marketing strategy of fashion products would be provided.