• Title/Summary/Keyword: reliability sensitivity

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The Effects of Internet Fashion Consumer Characteristics, Shopping Motivation, and Price Sensitivity on Negative Purchasing Behavior (인터넷 패션 소비자의 특성과 쇼핑동기 및 가격민감도가 부정적 구매행동에 미치는 영향)

  • Lee, Eun-Jin;Kim, Jong-Ouk
    • Fashion & Textile Research Journal
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    • v.15 no.3
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    • pp.381-392
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    • 2013
  • This study analyzed the effects of internet fashion consumer characteristics and shopping motivation on price sensitivity as well as the effect of price sensitivity on negative purchasing behavior. A survey was conducted from August 10 to September 20 in 2012 and 364 responses were used in the data analysis. The statistical analysis methods were frequency analysis, factor analysis, reliability analysis, and multiple regression analysis. The characteristics of internet fashion consumers were composed of innovation tendency, impulse buying tendency, information orientation, and variety seeking tendency. Shopping motivation was composed of convenient motivation, social motivation, hedonic motivation, product motivation, and economic motivation. The information orientation and variety seeking tendency of internet fashion consumers influenced the price search. The innovation tendency, impulse buying tendency, and variety seeking tendency of internet fashion consumers influenced the price importance. Convenient motivation, hedonic motivation, and product motivation positively affected the price search; however, social motivation negatively affected the price search. The social motivation, hedonic motivation, and economic motivation of internet fashion consumers positively affected price importance. Price search and price importance influenced the purchasing delay; in addition, price search influenced the switching intention. The results of this study provide useful information for customer management and internet shopping mall marketing strategies.

Reliability and Validity of the Alcohol Use Disorders Identification Test - Consumption in Screening for Adults with Alcohol Use Disorders and Risky Drinking In Japan

  • Osaki, Yoneatsu;Ino, Aro;Matsushita, Sachio;Higuchi, Susumu;Kondo, Yoko;Kinjo, Aya
    • Asian Pacific Journal of Cancer Prevention
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    • v.15 no.16
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    • pp.6571-6574
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    • 2014
  • Background: Alcohol is well established as a risk factor for cancer development in many organ sites. To assess the reliability and validity of the Alcohol Use Disorders Identification Test - Consumption (AUDIT-C) for detecting alcohol use disorders or risky drinking in Japanese adults the present study was conducted. Materials and Methods: A test-retest method was applied with a 2-week interval with 113 health care employees. The k coefficient, Cronbach's coefficient alpha, Spearman's correlation coefficient, and intraclass correlation coefficient (ICC) were determined and the validity of the AUDIT-C was analyzed using the data from a nationwide survey on adult alcohol use conducted in 2008 (n=4,123). Results: The reliability of the AUDIT-C score was high (${\kappa}$ coefficient=0.63, Cronbach's alpha=0.98, correlation coefficient=0.95, and ICC=0.95). According to the likelihood ratio and Youden index, appropriate cutoffs for the AUDIT-C were ${\geq}5points$ in men and ${\geq}4$ points in women. The sensitivity and specificity of these cutoffs for identifying ${\geq}8$ points on the AUDIT were 0.88 and 0.80, respectively, for men (positive likelihood ratio [LR+]=4.5) and 0.96 and 0.87, respectively, for women (LR+=7.7). The sensitivity and specificity of the cutoffs for identifying ${\geq}12$ points on the AUDIT were 0.90 and 0.84, respectively, for men (LR+=5.8) and 0.93 and 0.94, respectively, for women (LR+=15.8). The sensitivity and specificity of the cutoffs for identifying ${\geq}16$ points on the AUDIT were 0.93 and 0.80, respectively, for men (LR+=4.7) and 0.92 and 0.98, respectively, for women (LR+=55.6). With higher scores on the AUDIT, the specificity decreased and false-positives increased. The appropriate cutoffs for identifying risky drinking were the same for both genders. Conclusions: The reliability and validity of the AUDIT-C are high, indicating that it is useful for identifying alcohol use disorders or risky drinking among the general population in Japan, a group at high risk of cancer development.

Reliability-based Design Optimization using Multiplicative Decomposition Method (곱분해기법을 이용한 신뢰성 기반 최적설계)

  • Kim, Tae-Kyun;Lee, Tae-Hee
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.22 no.4
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    • pp.299-306
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    • 2009
  • Design optimization is a method to find optimum point which minimizes the objective function while satisfying design constraints. The conventional optimization does not consider the uncertainty originated from modeling or manufacturing process, so optimum point often locates on the boundaries of constraints. Reliability based design optimization includes optimization technique and reliability analysis that calculates the reliability of the system. Reliability analysis can be classified into simulation method, fast probability integration method, and moment-based reliability method. In most generally used MPP based reliability analysis, which is one of fast probability integration method, if many MPP points exist, cost and numerical error can increase in the process of transforming constraints into standard normal distribution space. In this paper, multiplicative decomposition method is used as a reliability analysis for RBDO, and sensitivity analysis is performed to apply gradient based optimization algorithm. To illustrate whole process of RBDO mathematical and engineering examples are illustrated.

Flexural Reliability Assessment of PSC-I Girder Rail Bridge Under Operation (사용중 PSC-I 거더 철도 교량의 휨모멘트에 대한 신뢰도 분석)

  • Kim, Ki Hyun;Yeo, Inho;Sim, Hyoung-Bo
    • Journal of the Korean Society for Railway
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    • v.19 no.2
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    • pp.187-194
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    • 2016
  • It is necessary to determine reliability indexes of existing railway bridges prior to setting up a proper target reliability index that can be used to introduce a reliability based limit state design method to design practice. Reliability is evaluated for a six PSC-I girder railway bridge, which is one of many representative types of double-track railway bridges. The reliability assessment is carried out for an edge girder subjected to bending moment. In the assessment, the flexural resistance and the fixed-load effect were obtained using existing statistical values from previous research on the introduction of limit state design to road bridge design. On the other hand, the live-load effect was determined using statistical values obtained from field measurement for the Joong-ang corridor, on which heavy freight trains are frequently passing. The reliability assessment is performed by AFOSM(Advanced First Order Second Moment method) for the limit state equation, and a sensitivity analysis for the reliability is performed for each factor of the load and resistance effects.

Probability of Failure on Sliding of Monolithic Vertical Caisson of Composite Breakwaters (혼성제 직립 케이슨의 활동에 대한 파괴확률)

  • 이철응
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.14 no.2
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    • pp.95-107
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    • 2002
  • A reliability analysis on sliding of monolithic vertical caisson of composite breakwaters is extensively carried out in order to make the basis for the applicability of reliability-based design method. The required width of caisson of composite breakwaters is determined by the deterministic design method including the effect of impulsive breaking waves as a function of water depth, also studied interactively with the results of reliability analyses. It is found that the safety factor applied in current design may be a little over-weighted magnitude for the sliding of caisson. The reliability index/failure probability is also seen to slowly decrease as the water depth increases for a given wave condition and a safety factor. In addition, optimal safety factor can roughly be evaluated by using the concept of target reliability index for several incident waves. The variations of optimal safety factor may be resulted from the different wave conditions. Finally, it may be concluded from the sensitivity studies that the reliability index may be more depended on the incident wave angles and the wave periodsrather than on the bottom slopes and the thickness of rubble mound.

Comparison of Delirium Screening Instruments for the Elderly (노인의 섬망 사정을 위한 도구의 임상적 사용 용이성에 관한 연구)

  • Lee, Young Whee;Chang, Sung Ok;Kong, Eun Suk;Kim, Nam Cho;Kim, Chun Gill;Kim, Hee Kyung;Song, Misoon;Ahn, Soo Yeon;Cho, Myung Ok;Choi, Kyung Sook
    • Korean Journal of Adult Nursing
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    • v.25 no.6
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    • pp.655-664
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    • 2013
  • Purpose: This study was undertaken to identify which delirium screening instrument would be more useful in clinical practice. Methods: Data were collected from 118 nurses from six hospitals in five provinces in Korea. For the delirium screening three instruments were compared: NEECHAM Confusion Scale (NEECHAM), Nursing Delirium Screening Scale (Nu-DESC), Delirium Observation Scale (DOS). The MMSE-K was used for concurrent validity. The nurse subjects were surveyed as to the practical clinical value of each instrument. Cronbach's ${\alpha}$ coefficient and Kuder-Richardson 20 were used to confirm the reliability. Results: The range of three scales reliability was .70~.82 and the range of correlation coefficient was .63~.82 with MMSE-K. For sensitivity of NEECHAM, Nu-DESC and DOS was 1.00, 1.00 and 0.81 respectively and specificity NEECHAM, Nu-DESC and DOS was 0.88, 0.89 and 0.89 respectively. Nurses rated the practical use of the DOS scale as significantly easier to use than the NEECHAM and Nu-DESC. Conclusion: NEECHAM, Nu-DESC and DOS scales were acceptable in terms of reliability, validity, sensitivity and specificity. However, nurses rated the DOS scale as easier scale to use and had more relevance to their practice.

Blood stasis syndrome questionnaire II and its reliability and validity (어혈 진단 설문지 II의 신뢰도 및 타당도)

  • Kang, Byoung-Kab;Ko, Mi Mi;Jung, Jeeyoun;Lee, Ju Ah
    • Journal of Society of Preventive Korean Medicine
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    • v.21 no.1
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    • pp.41-48
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    • 2017
  • Objectives : The aims of the current study were to assess the reliability and validity of the CoRe-Ditec-BS Questionnaire-II (BSQ-II; Blood stasis questionnaire-II) with 8 items including 5 items related women added to BSQ-I that was consisted of 36 items and developed in 2013. Methods : Between May 2014 and November 2014, 411 patients from 3 traditional Korean medical hospitals were asked to complete the BSQ-II. Each patient was independently diagnosed with BSS by two traditional Korean medical physicians from the same site. We estimated the internal consistency using Cronbach's ${\alpha}$ coefficient, the discriminant validity using the means score of BSS, and the predictive validity using logistic regression (sensitivity and specificity). Results : The BSQ-II had satisfactory internal consistency (Cronbach's ${\alpha}$ coefficient=0.765) and validity, with significant differences in the mean scores between the BSS($63.60{\pm}9.56$) and non-BSS groups($48.36{\pm}5.93$). The area under the receiver operating curve was about 98%, and the sensitivity and specificity were 91.4% and 94.9%, respectively. Conclusions : These results suggest that the CoRE-Ditec-BSQ-II is more reliable and valid instrument for estimating BSS than BSQ-I.

Reliability-Based Topology Optimization Using Performance Measure Approach (성능함수법을 이용한 신뢰성기반 위상 최적설계)

  • Ahn, Seung-Ho;Cho, Seon-Ho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.1
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    • pp.37-43
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    • 2010
  • In this paper, a reliability-based design optimization is developed for the topology design of linear structures using a performance measure approach. Spatial domain is discretized using three dimensional Reissner-Mindlin plate elements and design variable is taken as the material property of each element. A continuum based adjoint variable method is employed for the efficient computation of sensitivity with respect to the design and random variables. The performance measure approach of RBDO is employed to evaluate the probabilistic constraints. The topology optimizationproblem is formulated to have probabilistic displacement constraints. The uncertainties such as material property and external loads are considered. Numerical examples show that the developed topology optimization method could effectively yield a reliable design, comparing with the other methods such as deterministic, safety factor, and worst case approaches.

Sensitivity analysis of serological tests for detection of disease in cattle (소 질병 검출을 위한 혈청학적 검사의 민감도 평가)

  • Lee, Sang-Jin;Moon, Oun-Kyong;Pak, Son-Il
    • Korean Journal of Veterinary Research
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    • v.50 no.1
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    • pp.43-48
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    • 2010
  • Animal disease surveillance system, defined as the continuous investigation of a given population to detect the occurrence of disease or infection for control purposes, has been key roles to assess the health status of an animal population and, more recently, in international trade of animal and animal products with regard to risk assessment. Especially, for a system aiming to determine whether or not a disease is present in a population sensitivity of the system should be maintained high enough not to miss an infected animal. Therefore, when planning the implementation of surveillance system a number of factors that affecting surveillance sensitivity should be taken into account. Of these parameters sample size is of important, and different approaches are used to calculate sample size, usually depending on the objective of surveillance systems. The purpose of this study was to evaluate the sensitivity of the current national serological surveillance programs for four selected bovine diseases assuming a specified sampling plan, to examine factors affecting the probability of detection, and to provide sample sizes required for achieving surveillance goal of detecting at least an infection in a given population. Our results showed that, for example, detecting low level of prevalence (0.2% for bovine tuberculosis) requires selection of all animals per typical Korean cattle farm (n = 17), and thus risk-based target surveillance for high risk groups can be an alternative strategy to increase sensitivity while not increasing overall sampling efforts. The minimum sample size required for detecting at least one positive animal was sharply increased as the disease prevalence is low. More importantly, high reliability of prevalence estimation was expected with increased sampling fraction even when zero-infected animal was identified. The effect of sample size is also discussed in terms of the maximum prevalence when zero-infected animals were identified and on the probability of failure to detect an infection. We suggest that for many serological surveillance systems, diagnostic performance of the testing method, sample size, prevalence, population size, and statistical confidence need to be considered to correctly interpret results of the system.

Optimization of the Deep-sea Pressure Vessel by Reliability analysis (신뢰성 해석을 이용한 심해용 내압용기의 최적화)

  • JOUNG TAE-HWAN;HO IN-SIKN;LEE JAE-HWAN;HAN SEUNG-HO
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.190-197
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    • 2004
  • In order to consider statistical properties of probability variables used in the structural analysis, the conventional approach using the safety factor based on past experience usually estimated the safety of a structure. Also, the real structures could only be analyzed with the error in estimation of loads, material characters and the dimensions of the members. But the errors should be considered systematically in the structural analysis. In this paper, we estimated the probability of failure of the pressure vessel. And also, this paper presents sensitivity values of the random variable. Finally, we show that reliability index and probability of failure can present the tolerance limit of dimension of randam variables.

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