• Title/Summary/Keyword: First- and second-order sensitivities

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Study on Optimum Design for Embankment Construction on Soft Ground Treated by SCP (SCP개량지반상에 성토시공 시 최적설계에 관한 연구)

  • Chae, Jong-gil;Park, Yeong-Mog;Jung, MinSu
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.29 no.6C
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    • pp.251-258
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    • 2009
  • In this study, the optimum design conditions for embankment construction on soft clay layer improved by soil compaction pile (SCP) are discussed by comparing the practical design method to the reliability design which is based on the loss function and advanced first order second moment (AFOSM) method. The results are summarized as follows; 1) the relationship between safety factor and failure probability becomes heavy exponentially, failure probability decreases rapidly till 1% approximately until safety factor is smaller than 1.2 and after then, failure probability decrease gradually along the increase of the safety factor. The design safety factor of 1.2 may be the critical value that has been established on considering both relationships appropriately, 2) the safety factor of 1.15 at the minimum expected total cost is a little smaller than the design safety factor of 1.2 and the failure probability is about 1%, 3) the sensitivities of the ratio of stress share and the internal friction angle of sand is larger than the variables related the undrained shear strength of soft layer. This result means that the distribution characteristic of n and ${\phi}$ influences on the stability analysis considerably and they should be considered necessarily on stability analysis of embankment on soft layer improved by SCP, 4) new failure points of the input variables at the design safety factor of 1.2(below failure probability of 0.1~0.3%) is far 1~2 times of standard deviation from the initial design values of themselves.

A Study on the Sensitibities of Cashflow and Growth Opportunities to Investments (기업투자와 성장기회, 현금흐름의 민감도에 관한 실증연구)

  • Lee, Won-Heum
    • The Korean Journal of Financial Management
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    • v.24 no.2
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    • pp.1-40
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    • 2007
  • We test a model of investment-cashflow-growth opportunities relationship in order to estimate the sensitivities to investments. In this study, we use a new proxy variable for the value of growth opportunities(hereafter "VGO"), which is based on the seminal papers of M&M(1958:1961:1963) and Lee(2006;2007). The empirical findings on the sensitivities of cashflow and growth opportunities are as follows. First, when the traditional proxy variables for the growth opportunities such as Tobin's Q, MBR and sales growth are included with the new proxy VGO in the estimation, their coefficients are turned out to be insignificant. Second, only the new proxy variable VGO shows a statistically significant positive sensitibity to investment, which can be regarded that the growth opportunities hold the positive influences to investments. Third, the Tobin's Q can be decomposed into three factors such as the value of growth opportunities(VGO), the value of asset-in-place and valuation errors. It turns out that only the VGO shows a statistically significant positive relationship with investment among others. This means that the new variable VGO is a good proxy variable for the growth opportunities in the investment-cashflow sensitivity analysis. In sum, thanks to the above findings in this study, we can say that it will not be proper to choose a proxy variable for the growth opportunities from the traditional set of proxies such as Tobin's Q, MBR, or sales growth rate.

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The Effect of Youth's Experience of School Violence on Cyber Violence -Focus on the Multiple Mediating Effects of Human Rights Sensitivity and Peer Conformity- (청소년의 학교폭력 경험이 사이버폭력에 미치는 영향 - 인권감수성과 또래동조성의 다중매개효과를 중심으로 -)

  • Kim, Jung-Ae
    • The Journal of the Korea Contents Association
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    • v.21 no.5
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    • pp.446-464
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    • 2021
  • The purpose of this study is to verify the multi-mediated effects of human rights sensitivity and peer-coordination in the relationship between teenagers' school violence experience and cyberbullying in order to find alternatives to prevent cyberbullying as teenagers increase their use of smartphones. In order to achieve this research goal, four middle schools were selected by the education office located in downtown Busan and analyzed on 908 middle school students. The results of the study are as follows. First, school violence experiences have been shown to affect cyberbullying. Second, the experience of abuse and neglect during school violence affected human rights sensitivity, but the experience of damage did not affect human rights sensitivity. Third, among school violence experiences, the experience of damage and abuse influenced peer co-operation, but the experience of sitting on the sidelines did not affect peer co-operation. Fourth, human rights sensitivity affected cyberbullying. Fifth, peer groupings affected cyberbullying. Sixth, human rights sensitivity influenced peer-reaction. Seventh, among human rights sensitivities, bystander experience and cyberbullying were found to be mediating bystander experience and cyberbullying, but the damage experience and abuse experience did not have a mediating effect in human rights sensitization and cyberbullying. Eighth, peer cooperation was found to be mediating cyberbullying, but there was no mediating effect between on-the- sidelines experience and cyberbullying. Ninth, human rights sensitivity and peer creation are shown to mediate the relationship between on-the- sidelines experience and cyberbullying sequentially. However, human rights sensitivity and peer creation did not mediate cyberbullying sequentially between the experience of damage and the experience of perpetration. The implications of this study were to verify the effects of teenagers' school violence damage experience, abuse experience, and bystander experience on cyberbullying, and multiple interventions of human rights sensitivity and peer group.