• Nuclear Engineering and Technology
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• 제45권1호
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• pp.99-106
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• 2013

Thermal fatigue is a significant long-term degradation mechanism in nuclear power plants. In particular, as operating plants become older and life time extension activities are initiated, operators and regulators need screening criteria to exclude risks of thermal fatigue and methods to determine significant fatigue relevance. In general, the common thermal fatigue issues are well understood and controlled by plant instrumentation at fatigue susceptible locations. However, incidents indicate that certain piping system Tee connections are susceptible to turbulent temperature mixing effects that cannot be adequately monitored by common thermocouple instrumentations. Therefore, in this study thermal fatigue evaluation of piping system Tee-connections is performed using the fluid-structure interaction (FSI) analysis. From the thermal hydraulic analysis, the temperature distributions are determined and their results are applied to the structural model of the piping system to determine the thermal stress. Using the rain-flow method the fatigue analysis is performed to generate fatigue usage factors. The procedure for improved load thermal fatigue assessment using FSI analysis shown in this study will supply valuable information for establishing a methodology on thermal fatigue.

• Korean Membrane Journal
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• 제5권1호
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• pp.36-42
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• 2003

A Prediction of pervaporation performance was studied by solubility parameter calculation approach for the benzene/cyclohexane mixture system using rubbery blend membrane with various solubility parameters. The solubility parameter of the rubbery blend membranes were controlled with different blend ratio of the poly(acrylonitrile-co-butadiene), poly(styrene-co-butadiene) and poly(vinyl chloride). Screening of blend formulations was accomplished by simple swelling tests. When the content of NBR is increased, the swelling of both benzene and cyclohexane are decreased. However, the ratio of benzene swelling to swelling by cyclohexane (the swelling selectivity) increases. The same is true for blends in which the PVC content is increased. Adoption of a solubility parameter calculation provides an a priori methodology for seeking the best blend formulation.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.801-812
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• 1999

Change-point hazard rate models arise for example in applying "burn-in" techniques to screen defective items and in studing times until undesirable side effects occur in clinical trials. Sometimes in screening defectives it might be sensible to model two stages of burn-in. In a clinical trial there might be an initial hazard rate for a side effect which after a period of time changes to an intermediate hazard rate before settling into a long term hazard rate. In this paper we consider the multiple change points hazard rate model. The classical approach's asymptotics can be poor for the small to all moderate sample sizes often encountered in practice. We propose a Bayesian approach avoiding asymptotics to provide more reliable inference conditional only upon the data actually observed. The Bayesian models can be fitted using simulation methods. Model comparison is made using recently developed Bayesian model selection criteria. The above methodology is applied to a generated data and to a generated data and the Lawless(1982) failure times of electrical insulation.

• 연구윤리
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• 제4권1호
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• pp.23-29
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• 2023

Purpose: While prior research has identified ethical issues in marketing research, more research needs to identify specific ethical behaviors that marketing researchers should adopt. This research addresses this gap by identifying a few ethical behaviors that marketing researchers should consider. Research design, data and methodology: The present study has a justification to collect adequate textual data in the current literature using screening process based on the marketing ethics topics and themes, and ethical behaviors of marketing researchers. Results: Based on the literature analysis, a marketing ethics model, which included the principles of fairness, honesty, responsibility, and respect for stakeholders. Since the rise of e-commerce and technology, a growing demand for a method to analyze website user behavior has been growing. Researchers in the field of marketing are responding to this demand by creating innovative interactive platforms. Conclusions: The term "ethical practices in market research" refers to a collection of best practices that, when followed, increase the likelihood that the research carries out is ethical, fair, and accurate. Because there needs to be more theoretical work done on the topic, there should be more empirical studies on ethical behaviors in marketing research.

• 한국지하수토양환경학회지:지하수토양환경
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• 제8권3호
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• pp.61-73
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• 2003

계면활성제를 이용한 오염 토양의 세척 공법 적용시 오염물질의 분배를 결정할 수 있는 모델을 개발하였다. 이 모델을 활용하여 세척효과를 극대화할 수 있는 계면활성제의 선정 방법, 물 첨가량 효과, 최적 세척 방법을 예시하였다. 오염물질은 naphthalene, phenanthrene, pyrene, 계면활성제는 Triton X-100, Tergitol NP-10, Igepal CA-720, Brij 30을 대상으로 하였다. 동일한 총량의 계면활성제를 사용할 때 물의 첨가량이 증가하더라도 세척효과의 큰 증가 효과가 없었다. 동일한 총량의 물 및 계면활성제를 사용할 경우 1회 세척보다 연속 세척이 더 효과적이었으며, 연속 세척에서 물과 계면활성제를 동일하게 분배하는 것이 최적이었다. 물과 계면활성제 사용량 및 연속세척 회수에 따라 최적 계면활성제의 종류가 달라질 수 있었다. 본 모델 활용기법은 오염토양 세척 공법 적용시 복잡한 실험을 수행하기 이전에 계면활성제의 탐색과 최적 공정 설계에 활용될 수 있을 것이다.

• 보건의료산업학회지
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• 제7권3호
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• pp.95-109
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• 2013

The objective of this study is to assess the utilization and satisfactions about public health centers in Korea. For the analysis, the study utilize the nationwide data of 229,229 person on '2010 Community Health Survey' of Ministry of Health & Welfare. The statistical methodology used in the study is ${\chi}^2$, ANOVA, logistic regression model and multiple regression model. This study have four major findings. First, the significant affecting socio-demographic factors in utilizing public health center were gender, age, region, national basic living secured, married, income, education, job, state of health, chronic disease, unmet medical needs and utilization reason. Second, the most serviced category of health center user was vaccination both city and rural area and the next was certificate, primary care, health screening, other use, the mother and child in city area, primary care, health screening, certificate, home visiting health in rural area. Third, the significant affecting socio-demographic factors in satisfaction degree on health center service were age, region, national basic living secured, income, education, job, state of health, utilization degree and reason. Fourth, the most satisfied service of health service center was home visiting health in city area and mental health service in rural area and the next was nutritive control and the lowest satisfied service was user of certificate. The utilization and satisfaction on health center service were identified as different with residental area and user's characteristics. The politic effort are needed to support socially disadvantaged class and to narrow regional gap.

• 에너지공학
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• 제16권1호
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• pp.22-31
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• 2007

본 논문에서는 전력수급기본계획에 열병합발전설비의 최적용량을 반영할 수 있는 방법론을 개발하였으며 이에 따른 효과를 분석하였다. 이를 위해 열병합발전의 계획발전원가를 새로이 산정하여 심사곡선법(Screening Curve Method : SCM)을 이용한 정태적 최적 전원을 구성하였다. 이때, 열병합발전은 전기와 열을 생산하는 것이 가장 중요한 특징이므로 이를 고려할 수 있도록 열병합발전의 전기용량과 열용량을 모두 고려할 수 있는 계획발전원가를 도출하였다. 또한, 심사곡선법을 적용시키기 위한 부하지속곡선의 경우도 열병합발전의 특징을 고려하여 전기 및 열 부하지속곡선을 구성하여 적용하였다. 이때, 현재 수립된 전력 수급기본계획을 최대한 수정하지 않는 범위 내에서 열병합발전설비를 반영하도록 하였다. 열병합발전 건설계획을 반영한 계획안의 타당성을 증명하기 위해서 열병합발전 건설계획을 반영한 계획안과 전력수급기본계획을 비교 하였다. 즉, 발전량 기대치를 산출하여 발전원별 연료소비량 및 환경에 미치는 영향을 도출함으로써 열병합발전의 반영에 대한 효율성을 입증하였다.

• 청정기술
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• 제2권2호
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• pp.201-213
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• 1996

본 연구는 국제적 환경인식의 변화로 이제는 사후처리단계로서 환경문제를 다루는 것이 아니라 사전에 오염을 방지하고 오염의 배출을 최대한 억제하고 자원과 에너지를 최대한 효율적으로 이용하며 오염물질을 완전히 배출하지 않도록 하는 환경관리 수단이 요구됨에 따라 사용범위를 예측하기 힘들 정도로 확대되어 가는 LCA의 필요성과 국제적 논의동향을 살펴보고 대응방안을 제시하였다. 그리고 전자혁명 시대인 현대사회의 핵심인 반도체의 국가경쟁력을 높이고 환경을 새로운 수익창출의 기회로 삼는 계기를 마련하기위해 우리나라의 현실에 적응하기 쉬운 Screening LCA를 통해 반도체의 LCA를 수행함으로써 자원소비 측면에서는 Clip kg당 요구되는 투입물과 에너지의 요구량을 정량화하였고 환경영향 측면에서는 배출물의 영향을 정량화 함으로써 반도체 제품을 생산하는데 어느정도의 비용과 에너지와 물질이 투입되며 그것이 환경에 미치는 영향을 표시할 수 있으며 그로인해 문제공정을 도출하여 공정개선의 기회를 마련할 수 있다.

• Nuclear Engineering and Technology
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• 제48권6호
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• pp.1423-1432
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• 2016

The integrity of a reactor pressure vessel (RPV) related to pressurized thermal shocks (PTSs) has been extensively studied. This paper introduces an integrity assessment of an RPV subjected to a PTS transient based on the French codes. In the USA, the "screening criterion" for maximum allowable embrittlement of RPV material is developed based on the probabilistic fracture mechanics. However, in the French RCC-M and RSE-M codes, which are developed based on the deterministic fracture mechanics, there is no "screening criterion". In this paper, the methodology in the RCC-M and RSE-M codes, which are used for PTS analysis, are firstly discussed. The bases of the French codes are compared with ASME and FAVOR codes. A case study is also presented. The results show that the method in the RCC-M code that accounts for the influence of cladding on the stress intensity factor (SIF) may be nonconservative. The SIF almost doubles if the weld residual stress is considered. The approaches included in the codes differ in many aspects, which may result in significant differences in the assessment results. Therefore, homogenization of the codes in the long time operation of nuclear power plants is needed.

• 품질경영학회지
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• 제52권1호
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• pp.23-42
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• 2024

Purpose: This study aims to investigate the impact of two types of information quality, which are platform-oriented information quality and customer-oriented information quality, on customers' decision-making processes in the Online to offline (O2O) platform environment. Grounded in the product brokering efficiency model, which encompasses screening cost, evaluation cost, and decision quality, a model framework was developed. Furthermore, this study explores how these decision-making processes affect customer loyalty. Methods: Given that food delivery apps are the most widely used O2O service in Korea, this study targeted users of these apps for data analysis. We conducted hypothesis testing through a purposive sampling methodology focusing on food delivery app users. A Partial Least Squares Structural Equation Modeling analysis was conducted to analyze the data. The data collection occurred via an online survey from October to December 2021, with a total of 212 respondents participating. Results: The results of this study revealed the significant role of information quality in helping customers' decision processes while using food delivery apps. Specifically, it was found that platform-oriented information positively influences decision quality, while customer-oriented information significantly affects both the reduction of evaluation cost and the enhancement of decision quality. Additionally, the study indicated that lower evaluation costs and higher decision quality lead to increased platform loyalty. However, a reduction in screening cost did not have a significant impact on platform loyalty. Conclusion: While previous studies have overlooked the existence of two sides, service provider and user, in a platform, this research holds significance in its analysis of how information quality impacts loyalty by utilizing the two kinds of information quality. Practitioners can enhance customer loyalty to the platform by enriching customer-oriented information, thereby reducing customers' evaluation costs and encouraging more loyal usage of the platform.