• Journal of The Korean Society of Agricultural Engineers
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• v.53 no.6
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• pp.1-6
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• 2011

The conventional factor of safety as used in geotechnical engineering does not reflect the degree of uncertainty of the relevant parameters. Then in the geotechnical engineering, there have been efforts to reflect the uncertainties of the geotechnical properties through probabilistic analysis. In this study, a practical method for probabilistic analysis using the Hasofer-Lind reliability index is introduced. The method is based on the perspective of an ellipsoid that just touches the failure surface in the original space of the variables. The method is applied to prefabricated vertical drains (PVD) and compared with the result of Monte Carlo Simulation method.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.164-169
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• 2003

This paper is presented to a theory comparing each different systems by quantitatively analyzing reliability. availability, maintenance and safety. Reliability R(t) produced by the method here is used for MTBF calculation of system as reliability of normal state. It is possible to produce the failure rate of unsafety state through modelization of system only to use the failure rate, after yielding the failure rate of failure mode to each unsafety sate in case that unsafety state is defined with the function of systems applied.

• Journal of Biomedical Engineering Research
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• v.3 no.2
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• pp.131-134
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• 1982

We have successfully developed and produced 1 Channel EKG Monitor for operating room and ICU. Its safety, reliability and performance have been proved by clinical experiments in 10 hospitals during 4 months.

• 제어로봇시스템학회:학술대회논문집
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• 1989.10a
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• pp.727-730
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• 1989

Tokyo dome is Japan's first air dome. The roof of the dome is supported by air pressure. The centralized control system (YOKOGAWA's DCS : CENTUM and YEWPACK) is applied to automatically regurate the air pressure. The control system acquires signals from sensors positioned throughout the stadium and operate 36 fans to blow air into the dome. Great emphasis is placed on the reliability and safety of the system.

• Journal of the Korean Institute of Gas
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• v.16 no.1
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• pp.22-25
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• 2012

Welding and/or fusion in polyethylene(PE) system made on site is focused on the control of the welding or fusion process to follow proper procedure. The process control is important, but it is not sufficient for the long term reliability of a pipe system. To achieve the rate of failure close to zero, Non Destructive Testing(NDT) is necessary in addition to joining process control. For electrofusion joints several non-destructive testing methods are available. The ultrasonic phased array technique is possible to detect various defects including wire deviations and regions with lack of fusion. In this studies, testing was carried to detect the defect after electrofusion joining of polyethylene piping is utilized by the ultrasonic phased array technique. From testing data, ultrasonic phased array technique is recommended as a reliable non-destructive testing method.

• Safety and Health at Work
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• v.9 no.2
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• pp.224-231
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• 2018

Background: Organizations are pursing complex and diverse aims to generate higher profits. Many workers experience high work intensity such as workload and work pressure in this organizational environment. Especially, psychological burden is a commonly used term in workplace of Republic of Korea. This study focused on defining the psychological burden from the perspective of occupational safety and health and tried to develop a scale for psychological burden. Methods: The 48 preliminary questionnaire items for psychological burden were prepared by a focus group interview with 16 workers through the Copenhagen Psychosocial Questionnaire II and Mindful Awareness Attention Scale. The preliminary items were surveyed with 572 workers, and exploratory factor analysis, confirmatory factor analysis, and correlation analysis were conducted for a new scale. Results: As a result of the exploratory factor analysis, five factors were extracted: organizational activity, human error, safety and health workload, work attitude, and negative self-management. These factors had significant correlations and reliability, and the stability of the model for validity was confirmed using confirmatory factor analysis. Conclusion: The developed scale for psychological burden can measure workers' psychological burden in relation to safety and health. Despite some limitations, this study has applicability in the workplace, given the relatively small-sized questionnaire.

• International Journal of CAD/CAM
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• v.9 no.1
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• pp.1-16
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• 2010

When Deterministic Design Optimization (DDO) methods are used, deterministic optimum designs are frequently pushed to the design constraint boundary, leaving little or no room for tolerances (or uncertainties) in design, manufacture, and operating processes. In the Reliability-Based Design Optimization (RBDO) model for robust system design, the mean values of uncertain system variables are usually used as design variables, and the cost is optimized subject to prescribed probabilistic constraints as defined by a nonlinear mathematical programming problem. Therefore, a RBDO solution that reduces the structural weight in uncritical regions does not only provide an improved design but also a higher level of confidence in the design. In this work, we seek to improve the quality of RBDO processes using efficient optimization techniques with object of improving the resulting objective function and satisfying the required constraints. Our recent RBDO developments show its efficiency and applicability in this context. So we present some recent structural engineering applications demonstrate the efficiency of these developed RBDO methods.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.145-148
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• 2008

Recently, most of the international design code for concrete structures are trying to develope performance-based design specification with the limit state concept. To accomplish this object, it is necessary to define required performance and to measure the performance level of structure. The reliability index is one of the most attractive indexes to express the level of performance. In this paper, prestressed concrete beam is designed following member resistance factor and material resistance factor format and the reliability indexes are obtained and compared for different sets of resistance factors. Compatible sets of safety factors could be calibrated for given level of target reliability index applying the similar method presented in this paper.

• Fire Science and Engineering
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• v.29 no.2
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• pp.64-72
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• 2015

This study was carried out for the purpose of awareness survey for safety and fire fighting safety of lives and general safety for fire-fighting sector workers of Chung-nam region. The study was carried out in the questionnaire survey. The questionnaire respondents were 534 people such as fire-fighting public officials, fire-fighting company worker and safety-related public officials. The results of the questionnaire were subjected to statistical processing, such as frequency analysis using SPSS win 19.0. The reliability of the questionnaire in this study is a Cronbach' ${\alpha}=0.710{\sim}0.807$. According to the survey results, Only 15% of the surveyed are think that peoples safety consciousness was high, the remaining respondents think the low level of safety consciousness of peoples. According to the findings of the fire-fighting related safety consciousness, fire-fighting public officials safety consciousness level was 4.2 at standard 5 and safety-related public officials was 3.59. Safety consciousness level order was fire-fighting public officials > Fire-fighting company workers > safety-related public officials. According to the survey, the efforts to decrease the difference in recognition for safety is required.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.2
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• pp.156-165
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• 2009

Threat due to malfunction of space launch vehicles is significant since it is bigger and flights longer range than military missiles or scientific rockets. It is necessary to implement a flight safety system to minimize the possible hazard. Design objective of the tracking filter for the flight safety system is different from conventional tracking filters since estimation reliability is more emphasized than estimation accuracy. In this paper, a fusion tracking filter was implemented for processing multi-sensor data from a space launch vehicle. The filter performance is evaluated by analyzing the error of the estimated position and instantaneous impact point. Also a fault detection algorithm is implemented to guarantee fusion filter's reliability under any sensor failure and verified to maintain stability successfully.