• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.2
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• pp.225-230
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• 2017

To generate mechanical movements in one-shot devices such as missiles and space launch vehicles, pyrotechnic mechanical device(PMD) such as pin pullers using pyrotechnic charge has been widely used. Reliability prediction of pin pullers is crucial to successfully execute target missions for the one-shot devices. Because the pin pullers require destructive tests to evaluate their reliability, one would need about 3,000 samples of success to guarantee a reliability of 99.9 % with a confidence level of 95 %. This paper suggests the application of a probit model using the charge amount as a functional parameter for estimation of functional reliability of pin puller. To guarantee target reliability, we propose estimation methods of the lower bound of functional reliability by applying the probit model. Given lower bound of functional reliability, we quantitatively show that the optimum amount of charge increases as the number of samples decreases. Along with a variety of simulations the validity of our new model via real test results is confirmed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4A
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• pp.399-414
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• 2004

In this paper, an evolution of software reliability engineering in a large-scale software project is summarized. The considered software consists of many components, called functional blocks in software of switching system. These functional blocks are served as the unit of coding and test, and the software is continuously updated by adding new functional blocks. We are mainly concerned with the analysis of the effects of these software components in software reliability and reliability evolution. We analyze the static characteristics of the software related to software reliability using collected failure data during system test. We also discussed a pattern which represents a local and global growth of the software reliability as version evolves. To find the pattern of system software, we apply the S-shaped model to a collection of failure data sets of each evolutionary version and the Goel-Okumoto(G-O) model to a grouped overall failure data set. We expect this pattern analysis will be helpful to plan and manage necessary human/resources fur a new similar software project which is developed under the same developing circumstances by estimating the total software failures with respect to its size and time.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.3
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• pp.138-147
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• 2017

As the functions and structure of the system are complicated and elaborated, various types of structures are emerging to increase reliability in order to cope with a system requiring higher reliability. Among these, standby systems with standby components for each major component are mainly used in aircraft or power plants requiring high reliability. In this study, we consider a standby system with a multi-functional standby component in which one standby component simultaneously performs the functions of several major components. The structure of a parallel system with multifunctional standby components can also be seen in real aircraft hydraulic pump systems and is very efficient in terms of weight, space, and cost as compared to a basic standby system. All components of the system have complete operation, complete failure, only two states, and the system has multiple states depending on the state of the component. At this time, the multi-functional standby component is assumed to be in a non-operating standby state (Cold Standby) when the main component fails. In addition, the failure rate of each part follows the Weibull distribution which can be expressed as increasing type, constant type, and decreasing type according to the shape parameter. If the Weibull distribution is used, it can be applied to various environments in a realistic manner compared to the exponential distribution that can be reflected only when the failure rate is constant. In this paper, Markov chain analysis method is applied to evaluate the reliability of multi-functional multi-state standby system. In order to verify the validity of the reliability, a graph was generated by applying arbitrary shape parameters and scale parameter values through Excel. In order to analyze the effect of multi-functional multi-state standby system using Weibull distribution, we compared the reliability based on the most basic parallel system and the standby system.

• Proceedings of the KSR Conference
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• 2001.10a
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• pp.370-375
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• 2001

This paper is to suggest reliability modeling and analysis method of Electric Multiple Unit (EMU). It is necessary to identify subsystem/equipments of EMU and functional interfaces between subsystems in order to carry out reliability modeling of EMU properly. After identifying subsystem/equipments and functional interface, reliability allocation is performed using ARINC method. Reliability target of system/subsystems is verified in revenue service during the proper periods.

• Journal of Applied Reliability
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• v.1 no.1
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• pp.9-15
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• 2001

This paper modelled the fail-safe control logic through the frequency coding input and designed the 3-out of-6 self checker using the error detect coding method of information redundancy. In addition, this paper also peformed the reliability parallel numeric analysis regarding single module between fail-safe. control logic module and TMR(Triple Modular Redundancy), therefore, we achieved the result that the fail-safe control logic increases a functional reliability because of decreasing system waste cost and functional overhead rather than the existing hardware redundancy method.

• The Research Journal of the Costume Culture
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• v.17 no.1
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• pp.149-161
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• 2009

The purposes of this study are to examine older consumers' seeking benefits and purchase intentions for functional materials and their attitudes towards such materials and investigate the differences between purchasers and non-purchasers of functional materials in their seeking benefits for functional materials and their emphasis on self development and pursuit of fashion. In doing so, this study samples the older adult population living in Seoul, Busan, and Gyeonggi Province and analyzes 267 questionnaire responses obtained from the sampled older consumers. The main findings from the analysis are as follows: First, the older consumers' seeking benefits for functional materials were represented by three different dimensions: reliability, brands/fashion, and others-oriented pursuit. Second, the influence on the dimension of reliability was more significant in the order of knowledge on functional materials, pursuit of fashion, and emphasis on self-development the interest in garments and the pursuit of fashion were found to have significant influence on the dimensions of brands/fashion and others-oriented pursuit. Third, the respondents' attitudes towards functional materials showed significant correlations with the dimensions of reliability and others-oriented pursuit, while their purchase intentions for functional materials were significantly influenced by the dimensions of reliability and brands/fashion. Finally, when the differences in the respondents' seeking benefits for functional materials and their pursuit of fashion and emphasis on self-development were investigated according to whether or not they had ever purchased clothes made from any functional material, the group of purchasers showed a higher mean value than the non-purchaser group.

• Journal of Korea Society of Industrial Information Systems
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• v.20 no.4
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• pp.75-87
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• 2015

A redundant structure typically consists of primary component and standby component taking over the function of the primary component when the primary component fails. In this research, we consider a redundant structure in which a standby component can take over the function of more than one primary component when primary components fail. And we assume that the system has multi-state according to the states of components while all components have two states. This system is called as the multi-state redundant system with a multi-functional standby component. This type of redundant structure is frequently adapted by the system such as an aircraft in which the weight is an important design factor. In this paper, we propose new reliability model for this multi-state redundant system with a multi-functional standby component in order for evaluating the reliability of the system. Under the assumption that all components have constant failure rate, we evaluate the reliability of the system by applying Markov analysis method. And we investigate the effect of the multi-functional standby component by comparing reliabilities of the parallel system with multi-functional standby component and a simple parallel system and a parallel system with redundant structure.

• Journal of The Korean Society of Integrative Medicine
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• v.9 no.2
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• pp.63-73
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• 2021

Purpose : Selective functional movement assessment(SFMA) is a movement-based assessment tool designed for clinicians to diagnose and treat pain and functional physical problems. This concept is used for assistance in occupations related to movement, including clinical medical personnel, such as physical therapists, physical education instructors, and athlete coaches. Although this concept is widely used by clinicians, research and scientific proofs are relatively insufficient. This study aimed to review the literature on the understanding, reliability and effectiveness of SFMA, and to consider its role in the future of rehabilitation. Methods : In this review, a total of nine articles were selected according to the eligibility criteria of three major thesis topics. The main topics covered in the literature are reliability and effectiveness of clinical use of SFMA. To gather research articles, we searched official term 'Selective Functional Movement Assessment'. Among the searched 60 studies, nine were mentioned in this study that contained overlapping information and matched our desired topic. We reviewed four reliability analyses, four case reports, and one experimental study. Results : Reliability has an intermediate degree between high raters and within raters. The validity of the SFMA system is influenced by a combination of experience and logic; hence, further improvement is needed. Therefore, if the intervention was effective based on the diagnosis result, then biomechanical evidence is necessary to further support the claim. Conclusion : In future research, to use SFMA as a diagnostic tool with high accuracy, it is necessary to improve the reliability of the main problem through breakout, support for guidelines and validity and efficiency.

• Journal of the Korean Society for Railway
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• v.8 no.5
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• pp.434-438
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• 2005

In this paper, as the first step to assess and enhance the reliability of Korea High Speed Train, an electric traction system is selected and reliability analysis is carried out. The electric traction system is classified into subsystems and functional block diagrams and reliability block diagrams are drawn. Expressions for evaluating the reliability are derived and Mean Kilometer Between Service Failure is calculated using the trial track test results. The calculation results show reliability growth of the proposed system.

• Electronics and Telecommunications Trends
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• v.14 no.4 s.58
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• pp.1-9
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• 1999

In this paper, we summarize the lessons learned from the applications of the software reliability engineering to a large-scale software project. The considered software is the software system of the TDX-10 ISDN switching system. The considered software consists of many components, called functional blocks. These functional blocks serve as the unit of coding and test. The software is continuing to be developed by adding new functional blocks. We are mainly concerned with the analysis of the effects of these software components to software reliability and with the analysis of the reliability evolution. We analyze the static characteristics of the software related to software reliability using failure data collected during system test. We also discussed a pattern which represents a local and global growth of the software reliability as version evolves. To find the pattern of software of the TDX-10 ISDN system, we apply the S-shaped model to a collection of failure data sets of each evolutionary version and the Goel-Okumoto (G-O) model to a grouped overall failure data set. We expect this pattern analysis will be helpful to plan and manage necessary human/resources for a new similar software project which is developed under the same developing circumstances by estimating the total software failures with respect to its size and time.