• Journal of applied mathematics & informatics
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• 제23권1_2호
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• pp.153-165
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• 2007

This paper deals with the empirical Bayes two-action problem of testing $H_0\;:\;{\theta}{\leq}{\theta}_0$: versus $H_1\;:\;{\theta}>{\theta}_0$ using a linear error loss for some discrete nonexponential families having probability function either $$f_1(x{\mid}{\theta})=(x{\alpha}+1-{\theta}){\theta}^x\prod\limits_{j=0}^x\;(j{\alpha}+1)$$ or $$f_2(x{\mid}{\theta})=[{\theta}\prod\limits_{j=0}^{x-1}(j{\alpha}+1-{\theta})]/[\prod\limits_{j=0}^x\;(j{\alpha}+1)]$$. Two empirical Bayes tests ${\delta}_n^*\;and\;{\delta}_n^{**}$ are constructed. We have shown that both ${\delta}_n^*\;and\;{\delta}_n^{**}$ are asymptotically optimal, and their regrets converge to zero at an exponential decay rate O(exp(-cn)) for some c>0, where n is the number of historical data available when the present decision problem is considered.

• 한국구조물진단유지관리공학회 논문집
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• 제6권1호
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• pp.255-262
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• 2002

This paper presents a statistical analysis of empirical fragility curves for bridge. The empirical fragility curves are developed utilizing bridge damage data obtained from the 1995 Hyogoken Nanbu(Kobe) earthquake. Two-parameter lognormal distribution functions are used to represent the fragility curves with the parameters estimated by the maximum likelihood method. This paper also presents methods of testing the goodness of fit of the fragility curves and estimating the confidence intervals of the two parameters(median and log-standard deviation) of the distribution. An analytical interpretation of randomness and uncertainty associated with the median is provided.

• Nuclear Engineering and Technology
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• 제44권6호
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• pp.663-672
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• 2012

As software based digital I&C (Instrumentation and Control) systems are used more prevalently in nuclear plants, enhancement of software dependability has become an important issue in the area of nuclear I&C systems. Critical attributes of software dependability are safety and reliability. These attributes are tightly related to software failures caused by faults. Software testing and V&V (Verification and Validation) activities are hence important for enhancing software dependability. If the risky modules of safety-critical software can be predicted, it will be possible to focus on testing and V&V activities more efficiently and effectively. It should also make it possible to better allocate resources for regulation activities. We propose a prediction technique to estimate risky software modules by adopting machine learning models based on software complexity metrics. An empirical study with various machine learning algorithms was executed for comparing the prediction performance. Experimental results show SVMs (Support Vector Machines) perform as well or better than the other methods.

• Geomechanics and Engineering
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• 제17권3호
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• pp.247-252
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• 2019

Modulus of deformation of soil is an essential parameter used for design analysis of foundations, despite its importance; little attention is paid to developing empirical models for predicting the sensitivity of deformation moduli to other parameters that obtained from the pressuremeter tests. Various methods of analysis used to predict the horizontal at rest pressure from pressuremeter testing ($P_o$), these values showed distinctive variations, five methods used to evaluate the values of horizontal at rest pressure, these values been used to evaluate the modulus of elasticity using three methods of analysis. The values of modulus showed distinctive increase when the values of horizontal at rest pressure increase for the same pressuremeter test, these increases may reach to 65%. This sensitivity of the moduli to values of horizontal lead the author to propose some reliable methods of analysis for both the horizontal at rest pressure and the modulus of deformation from pressuremeter testing.

• 유통과학연구
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• 제12권9호
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• pp.95-99
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• 2014

Purpose - This study aims to develop and empirically test a multi-dimensional service convenience scale with the dimensions and measurement items of service convenience perceived by Korean consumers in retail contexts. Research design, data, and methodology - The study adopts the framework suggested by Berry et al. (2002) and conceptualizes service convenience as a second-order reflective construct comprising 31 items. Three department store chains (Hyundai, Lotte, and Shinsegae) and three discount store chains (E-mart, Homeplus, and Lotte Mart) were involved 510 valid responses were used for the empirical testing. Results - The measurement model is acceptable for internal consistency, convergent validity, and discriminant validity. Further, the structural model results show that service convenience is positively related to satisfaction. Results of the rival model comparison indicate that the proposed second-order factor model provides a better fit to the data than both the five-factor and the one-factor model. Conclusions - The multi-dimensional, second-order conceptualization of service convenience is robustly supported. This study provides psychometrically valid scales to measure service convenience in retail contexts as conceptualized by Berry et al. (2002).

• The Journal of Asian Finance, Economics and Business
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• 제7권10호
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• pp.339-345
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• 2020

Human resource is considered as an important resource that enables organizations to achieve competitive advantage. As such, it is important to have engaged employees to drive the strategic objectives of the organization. The study focuses on variables that can promote employee engagement. Work-life balance and employee engagement have received attention in both academia and practice. Engaged employees are crucial in the achievement of the strategic objectives of organizations. Besides, the role of religious orientation in life and work has been gaining attention from management scholars. The paper attempts to fill the research gap by developing a conceptual model and propositions for empirical testing. Specifically, the study proposes that work-life balance is expected to act as a mediator in the relationship between religiosity and employee engagement. Furthermore, religiosity is included as a moderator since religious belief can strengthen the positive relationship between work-life balance and employee engagement. A systematic literature review was carried out. A framework and propositions for future studies have been developed. The proposed framework provides direction for scholars to empirically test the indirect relationship between work-life balance, religiosity and employee engagement. Empirical testing of the framework could provide insights into how work-life balance and religiosity promote employee engagement.

• 한국도로학회논문집
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• 제10권4호
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• pp.79-89
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• 2008

포장 공용성 모델은 역학적-경험적 포장설계법에서 포장의 수명을 결정하기 위한 가장 중요한 인자이다. 한국 포장연구 프로그램의 일환으로 한국형 포장설계법이 역학적-경험적 방법에 근거하여 현재 개발중에 있다. 본 연구에서는 포장 공용성모델중 아스팔트 혼합물의 영구변형 예측모델을 삼축압축 반복재하시험을 이용하여 개발하였다. 본 시험은 다양한 아스팔트 혼합물에 대하여 온도와 공극률을 변화시켜 하중재하 횟수에 따른 혼합물의 영구변형 특성을 조사하였으며, 본 시험결과를 이용하여 예측모델의 계수값을 결정하였다. 영구변형 예측모델의 계수값은 포장가속시험결과를 토대로 다양한 혼합물에 대한 시험결과를 이용하여 깊이에 따른 전단응력의 변화를 고려한 통합적인 소성변형 모델계수값을 정하는 것보다 혼합물의 종류에 따른 모델계수를 산정하는 것이 보다 정확한 결과를 예측할 것으로 판단된다.

• Geomechanics and Engineering
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• 제21권5호
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• pp.423-432
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• 2020

Hydraulic conductivity is one of the engineering properties of soil. This study focusses on the influence of cement content on the hydraulic conductivity of cemented sand, which is investigated based on the results from numerical analysis and laboratory testing. For numerical analysis the cemented samples were scanned using X-ray Computed Tomography (CT) while laboratory testing was carried out using a triaxial setup. Numerical analysis enables us to simulate flow through the sample and provides insight to the microstructure. It quantifies the pore volume, proportion of interconnected voids and pore size distribution in both cemented and uncemented samples, which could be computed only through empirical equations in case of laboratory testing. With reduction in global voids, the interconnecting voids within the samples also reduce with cement content. Gamma cumulative distribution function is used to predict the percentage of voids lesser than a given pore volume. Finally, the results obtained from both numerical analysis and laboratory testing are compared.

• Structural Monitoring and Maintenance
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• 제7권1호
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• pp.13-25
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• 2020

One of the most important aspects in structural health monitoring is the detection of fatigue damage. Structural components such as heavy-duty bolts work under high dynamic loads, and thus are prone to accumulate fatigue damage and cracks may originate. Those heavy-duty bolts are used, for example, in wind power generation and mining equipment. Therefore, the investigation of new and more effective monitoring technologies attracts a great interest. In this study the acoustic emission (AE) technology was employed to detect incipient damage during fatigue testing of a M36 bolt. Initial results showed that the AE signals have a high level of background noise due to how the load is applied by the fatigue testing machine. Thus, an advanced signal processing method in the time-frequency domain, the Hilbert-Huang Spectrum (HHS), was applied to reveal AE components buried in background noise in form of high-frequency peaks that can be associated with damage progression. Accordingly, the main contribution of the present study is providing insights regarding the detection of incipient damage during fatigue testing using AE signals and providing recommendations for further research.

• Genomics & Informatics
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• 제12권4호
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• pp.151-155
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• 2014

In November 2013, the US Food and Drug Administration (FDA) sent a warning letter to 23andMe, Inc. and ordered the company to discontinue marketing of the 23andMe Personal Genome Service (PGS) until it receives FDA marketing authorization for the device. The FDA considers the PGS as an unclassified medical device, which requires premarket approval or de novo classification. Opponents of the FDA's action expressed their concerns, saying that the FDA is overcautious and paternalistic, which violates consumers' rights and might stifle the consumer genomics field itself, and insisted that the agency should not restrict direct-to-consumer (DTC) genomic testing without empirical evidence of harm. Proponents support the agency's action as protection of consumers from potentially invalid and almost useless information. This action was also significant, since it reflected the FDA's attitude towards medical application of next-generation sequencing techniques. In this review, we followed up on the FDA-23andMe incident and evaluated the problems and prospects for DTC genetic testing.