• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.75-81
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• 2016

Tendon corrosion reliability in KICT-ultra high performance concrete (K-UHPC) bridges is assessed and predicted considering uncertainties in flexural bending capacity and corrosion occurrence. In post-tensioning bridge systems, corrosion is a one of most critical failure mechanisms due to strength reduction by it. During the entire service life, those bridges may experience lifetime corrosion deterioration initiated and propagated in tendons which are embedded not only in normal concrete but also in K-UHPC. For this reason, the time-variant corrosion performance has to be assessed. In the absence of in-depth researches associated with K-UHPC tendon corrosion, a reliability-based prediction model is developed to evaluate lifetime corrosion performance of tendon in K-UHPC bridges. In 2015, KICT built a K-UHPC pilot bridge at 168/5~168/6 milestone on Yangon-Mandalay Expressway in Myanmar, by using locally produced tendons which post-tensioned in longitudinal and lateral ways of K-UHPC girders. For an illustrative purpose, this K-UHPC bridge is used to identify the time-variant corrosion performance.

• International Journal of Highway Engineering
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• v.5 no.1 s.15
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• pp.1-10
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• 2003

The objective of pavement design, just as with the design of other structures, is to obtain the most economical designs at specified levels of reliability. Methods that yield designs with different levels of reliability are undesirable, and over the course of time design approaches in the U.S. and Europe have converged toward the Load and Resistance Factor Design (LRFD) format in order to assure uniform reliability. At present the LRFD format has been implemented in concrete, steel, wood and bridge design specifications. In this paper, reliability theories are used to illustrate the development of an LRFD format for Mechanistic-Empirical (M-E) design of flexible pavements as an alternative of its reliability module. It is shown in this paper that ten candidate pavement sections designed with a reliability level using the AASHTO design guide (1986) do not have uniform structural reliability in terms of pavement mechanistic distress such as fatigue cracking and the uniform reliability can be achieved by using the LRFD format.

• Journal of the Korean Society of Safety
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• v.31 no.6
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• pp.25-31
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• 2016

This paper has analyzed the structure, applicable regulations and the resistance characteristics of insulation ring type of CSST (Corrugated Stainless Steel Tubing for Gas). With the flammability test conducted in accordance with KS C IEC 60811-1-1, the evaluation of insulation resistance, temperature characteristics, and reliability has been conducted. An insulation ring type CSST consists of protective coating, tube, nut, insulation ring, packing, socket, and ball valve. Connecting an insulation ring type CSST to gas tubings for gas appliance is not permitted, moreover, the product shall be installed inside a sleeve pipe in case of buried installation such as the ceiling. Damages on protective coating and tube were detected when fire was applied to the test sample with a portable torch for 60 seconds. The insulation resistance of a normal product was $49.59M{\Omega}$, while that of the product completed the flammability test reduced to $9.21M{\Omega}$. The mean insulation resistance within the confidence Interval of 95% using the mini tap program 17 was $49.59M{\Omega}$ and the mean insulation resistance within the confidence interval reduced to $9.21M{\Omega}$. In the normal distribution analysis of 95% confidence interval, the value-P of the normal product was stable at 0.075 and AD(Anderson-Darling) statistic value was turned out to be 0.063, which is very normal, and the standard deviation was analyzed as 0.2586. The value P of the product completed the flammability test resulted in 0.005, the AD was 1.355 and the standard deviation reduced to 0.07908.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.383-386
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• 2017

Avionics, a type of embedded system, requires high safety and reliability. Failure of avionics equipment can have a significant impact on aircraft operations and, in the worst case, could result in loss of life for pilots and passengers. In this paper, we propose a Built-In-Test (hereafter referred to as BIT) design technique that can detect possible faults in avionics equipments in order to increase the reliability of avionics system and a design that can improve the Mean Time Between Failure (hereafter: MTBF) and applied it to real aviation electronic equipment to improve reliability.

• Journal of the Korean Society of Safety
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• v.22 no.6
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• pp.35-40
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• 2007

As a way of improving the safety of the chemical facilities, the risk based-inspection(RBI) was executed for the facilities of the applied petrochemical plant using KS-RBI Ver. 3.0 program developed based on the API-581 based resource document(BRD). From an evaluation result of KS-RBI program, we could find the evaluation of the process safety management(PSM) for the applied plant, risk of the applied process, risk of static facilities and pipes, and the demage mechanism of the facilities. Also, we could suggest a proper inspection plan(frequency and method of inspection) using the calculated risk and the status of the facilities. Therefore, the applied plant could be achieved a reduced inspection cost by an extension of inspection frequency, improved productivity, improved reliability of the facilities, and a computerized history management.

• Journal of Korean Society of Steel Construction
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• v.19 no.5
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• pp.435-454
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• 2007

In this study, we demonstrated the characteristics of the near-fault ground motion thatwas not considered in the domestic seismic design code and how the effect of the near-fault ground motion affects the response of cable-stayed bridges. Afterselecting the actual measurement records of the typical near- and far-fault ground motion, the characteristics of ground motion is analyzed using the elastic and inelastic response spectrum. Analyzing the response regarding the earthquake's characteristics on cable-stayed bridges by the typical three-type cable-stayed bridges and the actual cable-stayed bridge, the characteristics of responses about main members are compared and analyzed. Moreover,reliability analysis is accomplished using the results of the seismic response analysis, and the seismic safety of the cable-stayed bridges is evaluated quantitatively as a reliability index and probability of failure. According to the results of the response spectrum, the earthquake response analysis and the reliability analysis, because the effect of the near fault ground motion against the response of cable-stayed bridges is different from the effect of the existing far-fault ground motion, it should be considered as an important factor when designing cable-stayed bridges.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2A
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• pp.93-102
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• 2010

The numerical analysis and safety assessment by construction stages were considered the essential examination particular in order to solving the unstability of long-span bridges in the middle a construction. When estimating structural response characteristics by the construction stage analysis of long-span bridges, the influence of the near-field ground motion (NFGM) would be evaluated as a critical factor for the seismic design because it indicates clearly different aspects from the existing input earthquake motion data. Therefore, this study re-examined the response aspect of long-span bridges considering NFGM characteristics based on the response spectrum result, and advanced the presented numerical analysis program by the related research for conducting the construction stage analysis and reliability assessment of long-span bridges efficiently. The excellency of various construction schemes was assessed using the time history analysis result of critical member considering NFGM characteristics. For evaluating quantitative safety level, the reliability analysis was conducted considering the influence of external uncertainties included in random variables, and presented the safety index and failure probability of the critical construction stage by NFGM characteristics. In addition, the reliability result was examined the influence of internal uncertainties using monte carlo simulation (MCS), and assessed the distribution aspect of the essential analysis result. It is expected that this study will provide the basic information for the construction safety improvement when performing seismic design of long-span bridges considering NFGM characteristics.

• Journal of the Korean Institute of Intelligent Systems
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• v.7 no.1
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• pp.34-44
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• 1997

The Belgian Nuclear Research Centre(SCK${\cdot}$CEN) has been a pioneer of the peaceful uses of nuclear energy after over forty years of existence. Recently, SCK${\cdot}$CEN's financial support of doctoral and postdoctoral research in close collaboration with universities has been a vital ingredient for securing a quality profile committed to the pursuit of execllence. FLINS, Fuzzy Logic and Intelligent technologies in Nuclear Science, was initially built within one of the postdoctoral research project at SCK${\cdot}$CEN. Among SCK${\cdot}$CEN's activities which will have an important impact on its scientific future, the application of fuzzy logic and intelligent technologies in nuclear science and engineering opens new domains in radiation protection, safety assessment, human reliability, nuclear reactor control, waste and disposal, etc. In this paper, we review the available literature on fuzzy logic in nuclear applications. We then present the initiative of R&D on fuzzy logic applications at SCK${\cdot}$CEN, namely, (1) safety control for a nuclear reactor, and (2) a safety evaluation model for nuclear transmission lines. By these two examples of nuclear applications, we illustrate the potential use of fuzzy logic in nuclear safety issues.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.554-557
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• 2006

For various historical and technical reasons, the safety of dams has been controlled by an engineering standards-based approach, which has been developed over many years, initially for the design of new dams, but increasingly applied over the past few decades to assess the safety of existing dams. And some countries were asked for risk assessment on existing dam, which included structural, hydraulic safety of dam and social risk. Whereas other countries have developed and adapted as an additional tool to assist in decision-making for dam safety management. Dam risk analysis should need the reliability data of dam failures, the past constructed history and management records of existing dam. It is thought with risk analysis method of dams for structural safety management in domestic that suitable to use consider an event tree, fault tree and conditioning indexes method.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.601-611
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• 2007

Onboard ATC performs the train speed ristriction function by receiving the speed limit on sections of track from wayside ATC. Onboard ATC can protect passenger from collision and derailment, and so on. So, the high level of safety and reliability for Onboard ATC is required, and by this reason, it is also required to improve the safety of Onboard ATC by applying the result of safety analysis on the Onboard ATC into its design and developing from the concept definition to the detailed desing phase. The paper introduces, when developing Onboard ATC, the safety improvement of Onboard ATC can be accomplished by applying system requirements from Risk Analysis into software and hardware.