• Computational Structural Engineering
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• v.9 no.1
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• pp.125-132
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• 1996

This study is to propose a practical and realistic reliability analysis by ETCM (Expected Total Cost Minimization). One of the main objectives is intended to propose the safety assessment and capacity rating of existing reinforced concrete members by evaluation index, that is RF(Rating Factor) from the results of the field test and inspection for reinforced concrete bridge. ETCM method is used for the reliability analysis of the proposed models. The proposed reliability model and method are applied to the safety assessment and system factors of reinforced concrete members.

• Computational Structural Engineering
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• v.6 no.1
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• pp.77-89
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• 1993

Current Bridge foundation design is based on Working Stress Design(WSD), but Load Factor Based on Optimum Reliability(LFBOR) design method is more rational than the WSD. For this reason, this study proposes a reliability based design criteria for the bridge foundation, which is most common type of bridge foundation(Shallow, Pile and Caission), and also proposes the theoretical basis of nominal safety factors of stability analysis by introducing the reliability theory. The limit state equations of stability analysis of bridge foundation and the uncertainty measuring algorithms of each equation are also derived by Cornell's MFOSM(Mean First Order 2nd Moment Methods)using the stability analysis fourmula Highway Bridge Design Codes.

• Journal of Applied Reliability
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• v.11 no.2
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• pp.187-212
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• 2011

KHP project sets total ownership cost as the target cost by applying CAIV and administrates total ownership cost through compromise analysis, a periodical estimate and management of design alternatives for each development. Based on expected cost results, sensibility of total ownership cost is analyzed complying with the change of reliability, availability, maintainability and other related factors. By considering potential total ownership cost saving methods, first of all, this paper identifies total ownership cost changing effects for each related factor, secondly, suggests total ownership cost and maintenance and operating cost saving methods via finding components that affect total ownership cost and lastly, suggests total ownership cost saving directions that may be applied to other projects in the future.

• Journal of Sensor Science and Technology
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• v.6 no.2
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• pp.131-136
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• 1997

The ISFET(ion sensitive field effect transistor), a semiconductor ion sensor, has many advantages over conventional ion sensors. Various single-sensor type ISFET pH-meters have been developed. However, they could not be applied in fields because their performances are directly affected by the sensor condition. With only one sensor, the system could be easily damaged from environmental factors, and reliability of it is decreased. Therefore, a 4-channel PH-meter system is proposed to improve the reliability of ISFET pH-meter. It has 4 ISFETS as ion sensor, and a software which contains a new calibration and measurement algorithm appropriate to the system. The reliability of the system was proved by measuring hydrogen ion concentration in the pH standard solutions and buffer solutions.

• International Journal of Automotive Technology
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• v.7 no.6
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• pp.757-762
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• 2006

Reliability of automotive parts has been one of the most interesting fields in the automotive industry. Especially, a small DC motor was issued because of the increasing adoption for passengers' safety and convenience. For several years, small DC motors have been studied and some problems of a life test method were found out. The field condition was not considered enough in the old life test method. It also needed a lot of test time. For precise life estimation and accelerated life test, new life test procedure was developed based on measured field condition. The vibration condition on vehicle and latent force on fan motor shaft were measured and correlated with each other. We converted the acceleration data into the load data and calculated the equivalent load from integrated value. We found the relationship which can be used for accelerated life test without changing the severity by using different loading factors.

• Journal of Applied Reliability
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• v.9 no.4
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• pp.351-362
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• 2009

This paper describes the issues that must be considered for the diagnosis and improvement of home network systems during the product development phase, and what must be done to resolve the reliability problem when a system is about to enter the Japanese market. It suggests that after the product specifications are determined, an accurate analysis of the environment is needed, and should include factors such as the temperature, humidity and power source of the country concerned. Furthermore, the video standards, residential complex installation environment, wiring specifications, and approval standards must be considered. All the above processes are described in this paper through the case study. The purpose of this paper is that suggested procedures in this research is to be used as a reference for developing similar products in the future.

• Computers and Concrete
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• v.15 no.2
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• pp.279-304
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• 2015

In this study, reliability analyses of steel fiber reinforced concrete (SFRC) corbels based on stochastic finite element were performed for the first time in literature. Prior to stochastic finite element analysis, an experimental database of 84 sfrc corbels was gathered from literature. These sfrc corbels were modeled by a special finite element program. Results of experimental studies and finite element analysis were compared and found to be very close to each other. Furthermore experimental crack patterns of corbel were compared with finite element crack patterns and were observed to be quite similar. After verification of the finite element models, stochastic finite element analyses were implemented by a specialized finite element module. As a result of stochastic finite element analysis, appropriate probability distribution functions (PDF's) were proposed. Finally, coefficient of variation, bias and strength reduction (resistance) factors were proposed for sfrc corbels as a consequence of stochastic based reliability analysis.

• Nuclear Engineering and Technology
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• v.15 no.1
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• pp.41-49
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• 1983

A computer code, BERD (Bayesian Estimation of Reliability Data), has been developed and tested in order to update the data for the reliability analysis of safety related systems in a specific nuclear power plant. The code has been used to derive the plant-specific data for reliability analysis of the auxiliary feedwater system of a pressurized water reactor. The prior information for components selected was taken from the U.S. Reactor Safety Study, WASH-1400, and the operating experiences from published licensee event reports. The results show that the updated data are well fitted to log-normal distribution curves and the error factors are reduced significantly.

• Nuclear Engineering and Technology
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• v.15 no.1
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• pp.11-22
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• 1983

The reliability of the Chemical and Volume Control System has been analyzed in a pressurized water reactor. The boration failure was taken to be the top event for this reliability analysis. A detailed fault tree was constructed and the minimal cut sets were derived. It was computed that the unavailability of the Chemical and Volume Control System due to boration failure was 1.497$\times$10$^{-5}$ during plant operation. It was found that the reliability of boric acid transfer pumps were the most important factors in the availability of the Chemical and Volume Control System. As expected, human errors also introduce the high system unavilability.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.8
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• pp.385-390
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• 2002

This paper presents a substation expansion planning method with quantitative analysis using ANP. To calculate the reliability factor and economy factor of the system, reliability indices and total construction cost is used. With these factors, new ANP model which select the best plan either economy or reliability among various alternatives is developed. This model can assist the decision making for the system planner. The usefulness of the method is verified by applying it to the large-scaled distribution system.