• Journal of the Korean Society of Clothing and Textiles
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• v.33 no.1
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• pp.33-44
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• 2009

This study is a survey of college students who have been exposed to a variety of clothing consumption environments such as online transactions through the Internet, with the purpose of examining the influence of salespersons attributes on college students' relationship commitment and perception of salespersons performance. The study conducted a questionnaire survey on 464 male and female students and used SPSS 12.0 for statistical data analyses such as mean, standard deviation, frequency analysis, reliability analysis, factor analysis, and multiple regression analysis. The results of this study can be summarized as follows: First, salespersons attributes such as appearance, expertise, customer orientation, and customer management fumed out as the factors that influence the satisfaction under relationship commitment at statistically significant levels. Likeability, customer orientation, and customer management were found to have statistically significant influence on perceived reliability of salespersons. Second, with respect to the influence of relationship commitment on customer performance, statistically significant factors included satisfaction and reliability. Customer orientation is considered most important by both male and female students among the salespersons attributes, followed in order by expertise, customer management, appearance, ethic and similarity. Likeability was found to be the least important attribute.

• Proceedings of the Korean Geotechical Society Conference
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• 2009.03a
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• pp.17-22
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• 2009

Reliability analyses were performed to quantify the risk in axially loaded large-scale pile foundations in consideration of pile-soil interaction and uncertainties on various design variables. The finite difference method based on an equivalent soil spring model and a load transfer method and Monte Carlo simulation method are integrated in the framework of reliabilty analysis. The applicability and efficiency of the proposed method in the safety assessment of axially loaded pile-soil system was verified using a realistic example. Since the proposed method can explicitly consider uncertainties in various design variables, and quantify failure probability of a pile foundation, it can be used to estimate risk, to obtain basic informations for life cycle cost analysis, and to develop code requirements for a reliability-based design of pile foundations.

• Journal of the Microelectronics and Packaging Society
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• v.20 no.3
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• pp.59-62
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• 2013

Experimental analyses on the solder joint reliability of plastic ball grid array under harsh random vibration were presented. The chips were assembled on the daisy chained circuit boards for the test samples preparation, half of which were processed for underfill to investigate the underfill effects on the solder failures. Acceptance and qualification levels were applied for the solder failure tests, and the overall controlled RMS of the power spectrum densities of the steps were 22.7 Grms and 32.1 Grms, respectively. It was found that the samples survived without any solder failure during the tests, demonstrating the robustness of the packaging structure for potential avionics and space applications.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.5
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• pp.185-190
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• 2006

The security analysis relates to the ability of the electric systems to survive sudden disturbances such as electric short circuits or unanticipated loss of system elements. It is composed of both steady state and dynamic security analyses, which are not two separate issues but should be considered together. In steady state security analysis including voltage security analysis, the analysis checks that the system is operated within security limits by OPF (optimal power flow) after the transition of a new operating point. On the other hand, dynamic security analysis deals that the transition will lead to an acceptable operating condition. Transient stability, which is the ability of power systems to maintain synchronism when subjected to a large disturbance, is a principal component in dynamic security analysis. Usually any loss of synchronism will cause additional outages. They make the present steady state analysis of the post-contingency condition inadequate for unstable cases. This is the reason of the need for dynamics of systems. Probabilistic criterion can be used to recognize the probabilistic nature of system components and shows the possibility of system security. A comprehensive conceptual framework for probabilistic static and dynamic assessment is presented in this paper. The simulation results of the Western System Coordinating Council (WSCC) system compare an analytical method with Monte-Carlo simulation (MCS). Also, a case study of the extended IEEE Reliability Test System (RTS) shows the efficiency of this approach.

• Nuclear Engineering and Technology
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• v.52 no.1
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• pp.87-100
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• 2020

Performance shaping factors (PSFs) in a human reliability analysis (HRA) are one that may influence human performance in a task. Most currently applicable HRA methods for nuclear power plants (NPPs) use PSFs to highlight human error contributors and to adjust basic human error probabilities (HEPs) that assume nominal conditions of NPPs. Thus far, the effects of PSFs have been treated independently. However, many studies in the fields of psychology and human factors revealed that there may be relationships between PSFs. Therefore, the inter-relationships between PSFs need to be studied to better reflect their effects on operator errors. This study investigates these inter-relationships using two data sources and also suggests a context-based approach to treat the inter-relationships between PSFs. Correlation and factor analyses are performed to investigate the relationship between PSFs. The data sources are event reports of unexpected reactor trips in Korea and an experiment conducted in a simulator featuring a digital control room. Thereafter, context-based approaches based on the result of factor analysis are suggested and the feasibility of the grouped PSFs being treated as a new factor to estimate HEPs is examined using the experimental data.

• Journal of Korean society of Dental Hygiene
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• v.20 no.6
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• pp.913-924
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• 2020

Objectives: This study was conducted to develop a dental hygienist's job satisfaction scale and to evaluate its validity and reliability. Methods: A total of 34 preliminary questions were composed based on the components commonly defined in previous studies and in-depth interviews. Results: The results of the study were practice activity, professional satisfaction, income, working conditions, patient relations, and co-worker relations using the exploratory factor analysis. Goodness of fit of the model assessed using confirmatory factor analysis generally met the criteria. On verification of the internal consistency, the Cronbach's alpha for the factors were as follows: 0.821 for practice activity, 0.822 for professional satisfaction, 0.847 for income, 0.765 for working condition, 0.743 for patient relations, and 0.747 for co-worker relations, which implied that the measurement tool was reliable. Through exploratory and confirmatory factor analyses, a total of 24 items for six factors: six items for practice activity factors, four items for professional satisfaction, three items for income, four items for working conditions, three items for patient relationships, and three items for coworker relations. Conclusions: Based on the aforementioned results, the validity and reliability of the dental hygienist's job satisfaction measurement tool were satisfactory. Thus, it may be used for assessing the job satisfaction of the dental hygienists in future.

• Child Health Nursing Research
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• v.28 no.3
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• pp.218-229
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• 2022

Purpose: This study aimed to develop and examine the validity and reliability of a self-efficacy scale for preventive health management related to premature labor (PHMSE-PL) for women of childbearing age. Methods: Instrument development and validation were undertaken in three steps: conceptualization through a literature review and in-depth interviews, item generation and evaluation of content validity, and evaluation of construct validity and reliability. The content validity, factorial structure validity, and internal consistency reliability of the PHMSE-PL were evaluated, and cognitive interviewing was undertaken. Data were analyzed using confirmatory factor analyses, Cronbach's α, and 95% confidence intervals (CIs). Results: The content validity was assessed by experts and was strengthened through cognitive interviews with women of childbearing age. The PHMSE-PL comprised 34 items across five factors. The construct validity of the PHMSE-PL was supported. Cronbach's α for the total scale was .97 (95% CI=.96-.97). Conclusion: An evaluation of the psychometric properties of the PHMSE-PL scale found it to be a valid and reliable tool for women of childbearing age. The scale appears to be useful for women of childbearing age to self-assess their preventive health management self-efficacy related to premature labor and for health professionals to evaluate and promote women's preventive health management.

• Steel and Composite Structures
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• v.43 no.3
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• pp.293-309
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• 2022

Accurate design models for predicting the shear resistance of headed studs in solid concrete slabs are essential for obtaining economical and safe steel-concrete composite structures. In this study, symbolic regression with genetic programming (GPSR) was applied to experimental data to formulate new descriptive equations for predicting the shear resistance of studs in solid slabs using both normal and lightweight concrete. The obtained GPSR-based nominal resistance equations demonstrated good agreement with the test results. The equations indicate that the stud shear resistance is insensitive to the secant modulus of elasticity of concrete, which has been included in many international standards following the pioneering work of Ollgaard et al. In contrast, it increases when the stud height-to-diameter ratio increases, which is not reflected by the design models in the current international standards. The nominal resistance equations were subsequently refined for use in design from reliability analyses to ensure that the target reliability index required by the Eurocodes was achieved. Resistance factors for the developed equations were also determined following US design practice. The stud shear resistance predicted by the proposed models was compared with the predictions from 13 existing models. The accuracy of the developed models exceeds the accuracy of the existing equations. The proposed models produce predictions that can be used with confidence in design, while providing significantly higher stud resistances for certain combinations of variables than those computed with the existing equations given by many standards.

• Steel and Composite Structures
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• v.49 no.1
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• pp.109-123
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• 2023

Headed studs welded to steel beams and embedded within the concrete of deck slabs are vital components of modern composite floor systems, where safety and economy depend on the accurate predictions of the stud shear resistance. The multitude of existing deck profiles and the complex behavior of studs in deck slab ribs makes developing accurate and reliable mechanical or empirical design models challenging. The paper addresses this issue by presenting a machine learning (ML) model developed from the natural gradient boosting (NGBoost) algorithm capable of producing probabilistic predictions and a database of 464 push-out tests, which is considerably larger than the databases used for developing existing design models. The proposed model outperforms models based on other ML algorithms and existing descriptive equations, including those in EC4 and AISC 360, while offering probabilistic predictions unavailable from other models and producing higher shear resistances for many cases. The present study also showed that the stud shear resistance is insensitive to the concrete elastic modulus, stud welding type, location of slab reinforcement, and other parameters considered important by existing models. The NGBoost model was interpreted by evaluating the feature importance and dependence determined with the SHapley Additive exPlanations (SHAP) method. The model was calibrated via reliability analyses in accordance with the Eurocodes to ensure that its predictions meet the required reliability level and facilitate its use in design. An interactive open-source web application was created and deployed to the cloud to allow for convenient and rapid stud shear resistance predictions with the developed model.

• Journal of the Korean Dietetic Association
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• v.30 no.1
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• pp.1-10
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• 2024

The purpose of this study was to verify the reliability and validity of the Job Meaning Scale for Nutrition Teachers (JMS-NT). The JMS-NT, the Nutrition Teacher Job Satisfaction Scale (NTJSS), and the Meaning in Life Questionnaire (MLQ) were administered to 180 nutrition teachers (female: 180, male: 0). The results showed that the JMS-NT had a three-factor structure in exploratory factor analysis. In addition, the test-retest reliability for all three factors of the JMS-NT was in the range of 0.69 to 0.85, and the internal consistency was in the range of 0.92 to 0.94, showing that they met the standards. The results of conducting Pearson correlation analyses between the JMS-NT and validity indicators such as the NTJSS and the MLQ were statistically significant, confirming the criterion validity of the scale. The above results show that the JMS-NT is a reliable and valid tool to measure the three factors of the job meaning of the nutrition teachers. Finally, the theoretical and practical significance, limitations, and future research tasks of the study were discussed.