• KSCE Journal of Civil and Environmental Engineering Research
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• v.1 no.1
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• pp.21-32
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• 1981

Recent trends in design standards development in some European countries and U.S.A. have encouraged the use of probabilistic limit sate design concepts. Reliability based design criteria such as LSD, LRFD, PBLSD, adopted in those advanced countries have the potentials that they afford for symplifying the design process and placing it on a consistent reliability bases for various construction materials. A reliability based design criteria for RC flexural members are proposed in this study. Lind-Hasofer's invariant second-moment reliability theory is used in the derivation of an algorithmic reliability analysis method as well as an iterative determination of load and resistance factors. In addition, Cornell's Mean First-Order Second Moment Method is employed as a practical tool for the approximate reliability analysis and the derivation of design criteria. Uncertainty measures for flexural resistance and load effects are based on the Ellingwood's approach for the evaluation of uncertainties of loads and resistances. The implied relative safety levels of RC flexural members designed by the strength design provisions of the current standard code were evaluated using the second moment reliability analysis method proposed in this study. And then, resistance and load factors corresponding to the target reliability index(${\beta}=4$) which is considered to be appropriate level of reliability considering our practices are calculated by using the proposed methods. These reliability based factors were compared to those specified by our current ultimate strength design provisions. It was found that the reliability levels of flexural members designed by current code are not appropriate, and the code specified resistance and load factors were considerably different from the reliability based resistance and load factors proposed in this study.

• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.645-655
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• 2021

Performance-based reliability analysis is a practical approach to investigate the seismic performance and stochastic nonlinear response of structures considering a random process. This is significant due to the uncertainties involved in every aspect of the analysis. Therefore, the present study aims to evaluate the performance-based reliability within a stochastic finite element (FE) framework for reinforced concrete (RC) shear walls that are considered as one of the most essential elements of structures. To accomplish this purpose, deterministic FE analyses are conducted for both squat and slender shear walls to validate numerical models through experimental results. The presented numerical analysis is performed by using the ABAQUS FE program. Afterwards, a random-effects investigation is carried out to consider the influence of different random variables on the lateral load-top displacement behavior of RC members. Using these results and through utilizing the Monte-Carlo simulation method, stochastic nonlinear analyses are also performed to generate random FE models based on input parameters and their probabilistic distributions. In order to evaluate the reliability of RC walls, failure probabilities and corresponding reliability indices are calculated at life safety and collapse prevention levels of performance as suggested by FEMA 356. Moreover, based on reliability indices, capacity reduction factors are determined subjected to shear for all specimens that are designed according to the ACI 318 Building Code. Obtained results show that the lateral load and the compressive strength of concrete have the highest effects on load-displacement responses compared to those of other random variables. It is also found that the probability of shear failure for the squat wall is slightly lower than that for slender walls. This implies that 𝛽 values are higher in a non-ductile mode of failure. Besides, the reliability of both squat and slender shear walls does not change significantly in the case of varying capacity reduction factors.

• IE interfaces
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• v.21 no.1
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• pp.109-119
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• 2008

Reliability of embedded softwares, as one of factors which affect system reliability, is the probability of failure-free software operation for a specified period of time in a specified environment. and Embedded software is different from general package software because hardware and operating system are tightly coupled to each other. Reliability evaluation models for embedded softwares currently used do not separate estimation and prediction models clearly, and even a standard model has not been proposed yet. In this respect, we choose a reliability estimation model suitable for embedded softwares among software evaluation models being used, and modified the model so as to accomodate recent software environments. In addtion, based on the model, the web-based reliability prediction tool RPX is developed. Finally, an embedded software is analyzed using the tool.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.9
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• pp.1589-1595
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• 2007

This paper suggests the advanced reliability assessment tool for railway signaling Hot-Standby sparing system. Existing reliability assessment for Hot-Standby sparing system controller is done by using single module mean failure rate based on approximated Hot standby sparing system function. Although approximated Hot standby sparing system function can be applied to various Hot standby sparing system, however, it is not able to reflect the exact system structure. In this paper, we suggest the advanced reliability function by identifying changeover-related failure factors and common failure mode which is not considered in existing approximated Hot standby sparing system reliability function via developing Hot standby sparing system model for railway signaling and applying FMECA to this model. Also. we compare reliability assessment results for model system to reliability assessment for existing system.

• Proceedings of the KSME Conference
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• 2001.11a
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• pp.240-245
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• 2001

Ultrasonic inspection system is consisted of the operator, equipment and procedure. The reliability of results in ultrasonic inspection is affected by its ability. Furthermore, the reliability of nondestructive testing is influenced by the inspection environment, other materials and types of defect. Therefore, it is very difficult to estimate the reliability of NDT due to various factors. In this study, the probability of detection, used logistic probability model and Monte Carlo simulation, estimated the reliability of ultrasonic inspection. The utility of the NDT reliability assesment is verified by the analysis of the data from round robin test applied these models.

• Nuclear Engineering and Technology
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• v.46 no.1
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• pp.55-62
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• 2014

A method for estimating software reliability for nuclear safety software is proposed in this paper. This method is based on the software reliability growth model (SRGM), where the behavior of software failure is assumed to follow a non-homogeneous Poisson process. Two types of modeling schemes based on a particular underlying method are proposed in order to more precisely estimate and predict the number of software defects based on very rare software failure data. The Bayesian statistical inference is employed to estimate the model parameters by incorporating software test cases as a covariate into the model. It was identified that these models are capable of reasonably estimating the remaining number of software defects which directly affects the reactor trip functions. The software reliability might be estimated from these modeling equations, and one approach of obtaining software reliability value is proposed in this paper.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.34 no.2
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• pp.85-89
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• 2021

High reliability thin film transistors are important factors for next-generation displays. The reliability of transparent a-IGZO semiconductors is being actively studied for display applications. A plasma treatment can fill the oxygen vacancies in the channel layer and the channel layer/insulating layer interface so that the device can work stably under a bias voltage. This paper studies the effect of plasma treatment on the performance of a-IGZO TFT devices. The influence of different plasma gases on the electrical parameters of device and its working reliability are reviewed. The article mentions argon, fluorine, hydrogen and several ways of processing in the atmosphere. Among these methods, F (fluorine) plasma treatment can maximize equipment reliability. It is expected that the presented results will form a basis for further research to improve the reliability of a-IGZO TFT.

• Journal of Service Research and Studies
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• v.7 no.1
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• pp.41-52
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• 2017

This study The purpose of this study is to analyze the effect of relationship factors and technical factors on the logistics performance of logistics companies. As a result of the analysis, information sharing, mutual trust, and mutual benefit of the inter-organizational relationship factors as factors affecting the logistics performance were analyzed as the factors that positively influence the logistics performance. In the technology factor, IT infrastructure and technology reliability are analyzed as factors that positively influence logistics performance, but system operation capacity is analyzed as a factor that does not positively affect logistics performance. Based on the results of this analysis, it can be confirmed that logistics companies can maximize the logistics performance by mutual sharing of information, mutual benefit and trust, and it is also confirmed that technical reliability is also an important factor.

• Journal of Distribution Science
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• v.13 no.6
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• pp.87-96
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• 2015

Purpose - Several domestic telecommunication companies have made a considerable effort to continuously grow and survive, and they have strived to thrive in the midst of mature market competition. To overcome this challenging situation and to grow continuously, while still meeting customer needs that are becoming more diverse and complicated with the passage of time, extensive support for internal marketing is essential. Without such internal support, companies face serious limitations and market roadblocks. The communication industry is a high-level service industry and a basic communications industry characteristic is its significant dependence on the employees delivering the services. Therefore, entrepreneurs in the information/communications industry, as well as existing competitors, should look to satisfy external customers through critical investment in internal customers (employees). Therefore, it is important for research to examine how internal factors influence technology innovation and service quality, which are the key drivers for companies that are seeking leading market positions. Research design, data, and methodology - The purpose of this study is to analyze the relationship of technology innovation and perceived service quality with the internal marketing factors in the communication industry and to offer suitable and effective internal marketing suggestions. The independent variables of this study are internal communication, education and training, the support of the executives, reward systems, and empowerment. The dependent variables are technology innovation and perceived service quality. Utilizing these, this paper studies the influence of internal marketing factors on technology innovation and perceived service quality. Results - The study results revealed the following. First, the identified internal marketing factors have a positive effect on technology innovation. Among the five internal marketing factors, three had a significant effect on product innovation, empowerment, the support of executives, and education and training, in this order. Second, the internal marketing factors also had a positive effect on the process innovation of technology innovation. The marketing factors, the support of executives, empowerment, internal communication, and education and training, in this order, significantly affect process innovation. Third, technology innovation had a positive effect on perceived service quality. All of the five service quality factors, namely, tangibles, reliability, assurance, responsibility, and empathy, in this order, significantly affect product innovation. Additionally, tangibles, reliability, responsibility, empathy, and assurance, in this order, significantly affect process innovation. Fourth, product and process innovation significantly affect tangibles and reliability in technology innovation. To enhance tangibles and reliability, process innovation should first be enhanced. Fifth, product and process innovation significantly affect responsibility and empathy in technology innovation. To enhance the responsibility and empathy, process innovation should first be enhanced. Sixth, product and process innovation significantly affect assurance in technology innovation. To enhance the assurance, product innovation should first be enhanced. Conclusions - According to the results, a company's internal marketing factors have a positive and significant effect on technology innovation and, further, product and process innovation have a positive and significant effect on the perceived serviced quality.

• Journal of Distribution Science
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• v.13 no.8
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• pp.91-96
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• 2015

Purpose - This study reviews the delivery of child welfare service quality and examines how the dimensions of the variables of customer satisfaction impact the results from a service distribution perspective. This study differs from existing research since it proposes that a recognized level of child welfare service quality is necessary to achieve customer satisfaction from the perspective of service distribution. Research design, data, and methodology - This study explores child welfare service quality factors that affect customer satisfaction. The study examines and analyzes demographic variables, service quality dimensions, and the causal relationships between child welfare service quality and customer satisfaction. Data from 300 child welfare cases were collected from organizations in Korea in the areas of Busan and Gyeongsangnamdo. The methods of analysis are as follow. First, using descriptive analysis frequency, the percentages were evaluated to assess the demographic variables. Second, Cronbach's α was used to test reliability and to evaluate the internal consistency of the measuring of items. Third, multiple regression analysis was conducted to find out how much the independent variable can affect customer satisfaction. Results - Five factors of child welfare service quality were identified in three categories: process quality (assurance, empathy), results quality (reliability, caring), and physical environment quality (tangibles). There were significant differences among the effects of the child welfare service quality factors on customer satisfaction. A multiple regression analysis was done with process quality (assurance, empathy), results quality (reliability, caring) and physical environment quality (tangibles) to test the hypothesis: assurance (t=2.434, p<0.05), empathy (t=3.677, p<0.001), reliability (t=3.271, p<0.05), caring (t=4.380, p<0.000), and tangibles (t=3.654, p<0.01) had a positive influence on child welfare service quality from a service distribution perspective. Therefore, hypotheses 1, 2, 3, 4, and 5 were supported. In addition, multiple regression analysis on the effects of the variables showed that caring (β=0.273), empathy (β=0.246), tangibles (β=0.265), reliability (β=0.152), and assurance (β=0.131) all had a positive and strong influence on child welfare service quality from a service distribution perspective. Therefore, all child welfare service quality categories (process, results and physical environment quality) were positively statistically significant. Conclusion - In this study, the main findings can be summarized as follows. First, the quality of service of child welfare consists of three dimensions of quality: process quality, results quality, and physical environment quality. The results of the multiple regression analysis also showed that caring and reliability were confirmed as more meaningful variables by the increasing loading factors. Second, the family members involved in child welfare proposed caring as the most important variable among the dimensions of service quality. Third, the results of the hypothesis testing using regression showed that all child welfare service quality factors had a positive impact on customer satisfaction. The results of the study could provide useful information to help increase the effectiveness of delivery strategies for child welfare service quality from a service distribution perspective.