• Journal of Applied Reliability
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• v.14 no.2
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• pp.93-96
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• 2014

RFID (Radio Frequency IDentification) system is recognition technology which can maintain various object's information. Reliability of RFID tags is the most important factor in RFID system. In this paper, we proposed ALT (Accelerated Life Test) method for UHF RFID tags. Temperature and humidity were adopted as stress factors and the accelerated life tests were conducted in three different conditions. We performed failure analysis for identifying failure mechanism and statistical analysis of test data. In the statistical analysis, we employed Inverse Power law for relationship between tag's life and stress. Through the statistical analysis, we proposed acceleration factor for several levels of temperature-humidity. The reliability qualification test plans were also designed for the tag's target reliability.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.4
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• pp.183-187
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• 2002

The efficient and rational transmission tariff structure is one of the crucial factors in creation of fair and competitive electricity markets. Transmission charge can be largely categorized into the line usage charge, system reliability charge, access charge and others. Any transmission tariff should be able to reflect these cost components reasonably. This paper suggests an approach amenable to allocating the transmission reliability costs reasonably with reflection of line sensitivity and line outage rate.

• Geotechnical Engineering
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• v.4 no.2
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• pp.15-24
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• 1988

To identify the stability of cantilever retaining wall in safe state by the deterministic method, these potential modes of such geotechnical failures as bearing capacity, horizontal sliding and overturning are analysed using Advanced First Order Second Moment (AFOSM) method. All design variables are assumed of the normal distribution and to be statistically independent. Considering the correlations between the single modes, structural system reliability index is 2. 05. Even if the safety factors are larger than the required value in the codes' by the conventional deterministic method, the system reliability of this structure may not be Judged to be safe state since the system reliability index is much lower than general value of 3.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.504-509
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• 2011

The military communication equipment is required the high reliability for operating adequate functions under severe conditions. This reliability is the essential element for the quality of the product, for the uncontrolled factors, such as the clearance, damage of the material, the reduction of stiffness, which are the designer is unable to handle. In this paper, the uncertainty for the design was supposed to the probability model for the military communication equipment, and the average of the objective function was minimized for reducing design uncertainty. The reliability-based design optimization which was implemented the limit state function was formulated into the mathematical model, so the reliable optimized structure was implemented than the base-line design.

• Journal of Korean Society for Quality Management
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• v.20 no.2
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• pp.94-108
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• 1992

This study involves an experiment for the cognitive experiment design and the human reliability in software engineering. Its overall objectives are to analyze common-cause human domain error and reliability in human-software interaction. A laboratory study was performed to analyze software engineers' task behavior in software production and to identify software design factors contributing to the effects in common cause failure redundancy. Common-cause model and its function were developed, then the main experiment using programming experts was conducted in order to define a new cognitive paradigm, in the aspects of identification, pattern recognition, and behavior domain for human reliability and quality control in software development. The results and analytical procedures developed in this research can be applied to reliability improvement and cost reduction in software development for many applications. Results are also expected to provide guidelines for software engineering quality control and for more effective design of human-software interface system.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1990.10a
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• pp.85-90
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• 1990

Current steel pile foundation design is bared an WSD, but the reliability based design method is more rational than the WSD. For this reason, this study proposes a reliability Index of the pile foundation by LFD which is most common type of pile foundation, and also proposes the theoretical bases of nominal safety factors of stability analysis by introducing the reliability theory. The measured bearing capacity data are analyzed to the descriptive statistics and classified into the four models of uncorrelated -normal(UNNO), uncorrelated -nonnormal(UNNN), correlated -normal(CONO), and correlated nonnormal (CONN). This study presents the comparisons of reliability index and check points using the AFSOM with respect to the four models as well as BASIC program.

• International Journal of Reliability and Applications
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• v.2 no.4
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• pp.269-280
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• 2001

The objective of this paper is to provide a model for effective implementation of costing RAM management in the design and procurement of production facility considering the system cost-performance trade-off. This research proposes a two-step approach of costing RAM design and test of system RAM for production facility. In Step 1, a static model is proposed to find an initial system configuration to meet the required performance based on system RAM and LCC and analyzes the trade-off relationships between various factors of RAM and LCC. In the second Step, we developed time and failure truncated models for system reliability test and analysis. For the computational purpose, we developed computer programs and have shown the sample results. By the sample test run, the proposed model has shown the possibilities to provide a good method to analyze system performance evaluation for both design and operational phase, This model can be applied to a wide variety of systems not only for costing RAM of the production facilities but also for the other kinds of equipment.

• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1188-1195
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• 2014

This paper presents an analytical technique for reliability evaluation of electrical distribution network (EDN) containing distributed generation (DG). Based on hierarchical levels of circuit breaker controlling zones and feeder sections, a directed-relation-graph (DRG) for an END is formed to describe the hierarchical structure of the EDN. The reliability indices of EDN and load points can be evaluated directly using the formed DRG, and the reliability evaluation of an EDN containing DGs can also be done without re-forming the DRG. The proposed technique incorporates multi-state models of photovoltaic and diesel generations, as well as weather factors. The IEEE-RBTS Bus 6 EDN is used to validate the proposed technique; and a practical campus EDN containing DG was also analyzed using the proposed technique.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.5
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• pp.593-602
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• 2004

We have developed a digital control rod control system not only to improve its performance but also to improve its reliability and speed of response so that it can replace the old fashioned analog system. However, a new developed digital control system should be tested to prove the validity by using any prototype or mock-up before application. The reliability prediction and the reliability block diagram analysis methods were adopted to verify the reliability of the developed hardware. For the case of software, especially fur a new developed control algorithm it has been tested to prove performances and validation by using a dynamic simulator and mock-up of control rod drive mechanism altogether. Here we want to present some key factors regarding to the new developed digital system with some verification procedures.

• International Journal of Reliability and Applications
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• v.17 no.2
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• pp.121-135
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• 2016

In this paper, we study a system of five components. One of them is a bridge network component. Each of these components is identical and has a failure rate as a function of time. The system components have non-constant failure rates. The given system is improved by using the reduction, hot duplication, and cold duplication methods. We derive the equivalence factors of the bridge structure system to be as another system improved according to these different methods. The ${\beta}-fractiles$ are obtained to compare the original system with these improved systems. Finally, we present numerical results to show the difference between these methods.