• Journal of the Korea institute for structural maintenance and inspection
• /
• v.8 no.3
• /
• pp.225-233
• /
• 2004

In this study, the seismic safety of containment building is assessed using response surface method. The structural analyses considering random variables such as load, resistance and analysis by ABAQUS are performed to obtain the structural response. The structural response is represented by polynomial of random variables, and the reliability analysis is performed by Level II method. Drucker-Prager failure criterion is applied as limit state function to take bi-axial stress states into account in the concrete. The lifetime probability of failure is evaluated by considering the lifetime of containment building, the annual occurrence rate of earthquake and the conditional probability of failure. Also the sensitivity analysis on the selection of sampling points is performed to obtain the steady results from response surface method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2011.10a
• /
• pp.659-661
• /
• 2011

In this paper, we propose a study of scheme to detect mobile object. In special zone needed detection, sensor network based system development can provide safety of pedestrian. Instead current CCTV, intelligent sensor network and service can provide reliability to guarantee safe zone. Base on pedestrian characteristic, if unusual situation is detected and it is included in previous agreed scenario, safety service can be provided.

• Journal of the Korean Society of Safety
• /
• v.3 no.2
• /
• pp.5-16
• /
• 1988

This study is conducted to evaluate the explosion of tolune storage tank in the petrochemical plant by Fault Tree Analysis. The conclusions are as follows; 1) Fault Tree diagram and the required computer program for evaluation of explosion accident is developed. 2) The probability of the top event, explosion accident, is $1.5\;{\times}\;10^{-8}$ per year, so there is almost no possibility of explosion during the life cycle of tank. However, the probability of Gate 6 and Gate 7 is 8.8 per month, therefore, attention should be paid to them for accident prevention. 3) The number of minimal cut sets is 67 sets which are not calculated the probability of each set, because of the lack of computer capacity. All the minimal cut sets should be examined case by case. However, it is necessary to be paid attention to COM1, 126, 131, and COM4 in minimal cut sets, because the number of appearance is so high. 4) The number path sets is 70 sets which are not calculated the probability of each set, because of the lack of computer capacity. It is very useful to prepare safety checklist by using this minimal path sets. Also, the events which appear many times, 123, COM5, 139, 127 and 128, are very high in reliability.

• Journal of Advanced Navigation Technology
• /
• v.24 no.5
• /
• pp.329-342
• /
• 2020

In this paper, we analyzed the requirements for the application of UAM, a new concept to solve the traffic congestion in large cities. First, the current domestic and foreign status of research and development related to UAM was investigated and the pros and cons and the time required for each mission radius were analyzed for various configurations of aircraft being commercialized. In addition, in order to analyze the market acceptance of the UAM, the individual's consciousness and reliability requirements were identified and safety requirements were analyzed through accident rate data for each aircraft type. Because it operates in a densely populated urban area, requirement analyses on noise and exhaust, which are environmental factors that can affect the community were performed, and requirements related to aircraft performance, certification standards, and airworthiness standards of FAA and EASA were also analyzed.

• Economic and Environmental Geology
• /
• v.33 no.4
• /
• pp.295-307
• /
• 2000

Probabilistic analysis is a powerful method to quantify variability and uncertainty common in engineering geology fields. In rock slope engineering, the uncertainty and variation may be in the form of scatter in orientations and geometries of discontinuities, and also test results. However, in the deterministic analysis, the factor of safety which is used to ensure stability of rock slopes, is based on the fixed representative values for each parameter without a consideration of the scattering in data. For comparison, in the probabilistic analysis, these discontinuity parameters are considered as random variables, and therefore, the reliability and probability theories are utilized to evaluate the possibility of slope failure. Therefore, in the probabilistic analysis, the factor of safety is considered as a random variable and replaced by the probability of failure to measure the level of slope stability. In this study, the stochastic properties of discontinuity parameters are evaluated and the stability of rock slope is analyzed based on the random properties of discontinuity parameters. Then, the results between the deterministic analysis and the probabilistic analysis are compared and the differences between the two analysis methods are explained.

• Fashion & Textile Research Journal
• /
• v.22 no.6
• /
• pp.762-776
• /
• 2020

This study tried to investigate the effect of the service quality attributes of the curation on the satisfaction, trust, and intention to continuous use of consumers in that curation services are derived in various forms and being greatly activated, there are not many academic discussions centered on them. Besides, differences between curation services by each service provider were also verified in this study. Data collection was conducted for one month in August 2019, with 373 men and women in their 20s. The results of the study are as follows. First, according to the result of investigating the variables that make effect on user satisfaction of curation service, it was identified that satisfaction has increased when figures of fulfillment, responsiveness, personalization, design, ease of use, and safety were higher. Second, among the variables that influence the reliability of the curation service, trust increases when user satisfaction, design, ease of use, and safety are higher. Third, satisfaction has a positive effect on trust, and both satisfaction and reliability affect the intention to continue use. Fourth, as a result of examining the difference in quality between the curation services divided by Curating subject, it was found that satisfaction, ubiquitous connectivity, and responsive quality were measured higher in the business operator service than in the user curation service.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.22 no.3
• /
• pp.343-348
• /
• 2013

In line with the advances in factory automation, various pieces of equipment are now operated in batch processes controlled by computers. However, many kinds of faults can occur in complicated and large systems, which can result in low productivity and economic loss. The reliability and safety of systems have been studied because of the difficulty of determining the severity and location of faults. Therefore, it is necessary to detect and diagnose such faults in order to guarantee the reliability and safety of the equipment. In this paper, a diagnosis method for the ball bearings of a hydraulic pump is applied using a vibration signal for the maintenance of injection molding equipment. The bearings' defects are selected as a main failure mode through a failure mode and effect analysis (FMEA). Usually, there are nonlinear and impulse components of vibration in a ball bearing with faults. For the effective fault diagnosis of a ball bearing, nonlinear diagnostic methods and time-frequency analysis are applied, in addition to the methods currently used, such as power spectrum, time series analysis, and statistical methods. As a result of this study, a failure diagnosis system is provided that is useful even for non-experts. This is a condition-based method that makes it possible to resolve problems in a timely and economical way, in contrast to the prior method, which required regular but wasteful maintenance based on the experience of expensive external experts.

• Journal of Korean Society of Transportation
• /
• v.34 no.1
• /
• pp.55-67
• /
• 2016

The purpose of this study is to analyze the correlation and the causal relation between the service quality, customer satisfaction and revisit intent of an urban railway. A structural equation model(SEM) was developed and analyzed using SPSS 21.0 and AMOS 21.0. The results showed that it satisfies the fitness of the model mostly: the reliability, convenience, safety of the service quality have a significant positive impact on the customer satisfaction (p<.05) and the tangibles(-.187) and responsiveness(-.103) have no impact on the customer satisfaction (p>.05.). The customer satisfaction has a significant positive impact on revisit intention (p<.001). The factors affecting the service quality and customers' satisfaction were found to be ranked as the order of reliability, convenience, safety, responsiveness, tangibility based on the high priority. The findings of this study will contribute to provide a practical tool to establish a mid-long term management plan and management strategies for boosting the customer satisfaction and creating revenue through the customized service of urban railway operating industry suffering chronic deficit.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.21 no.5
• /
• pp.649-657
• /
• 2018

It is essential that weapons which are mounted on aircraft need to prove its reliability and safety during its developments. A guided missile should have high reliability and safety throughout various tests which are including ground tests, captive flight tests, detailed technical tests and operational tests. In these various tests, it is vital that software of each component in the guided missile should be easily updated in order to correct algorithms or errors. In this paper, we propose a software update technique based on MDTP(mass data transfer protocol) which are defined in MIL-STD-1760. The proposed techniques have the following advantages: First, software of each unit in a weapon can be updated through a test equipment without disassemble a guided missile. Second, development periods for a software update can be reduced by reusing MDTP. Third, we can easily maintenance of the software because it is based on standard. We proved its efficiency and validity through experiments. Therefore, the proposed technique should be effectively utilized for software update of a weapon mounted on an aircraft during development processes.

• Fire Science and Engineering
• /
• v.34 no.3
• /
• pp.35-42
• /
• 2020

The accurate prediction of fire detector activation time is required to ensure the reliability of fire modeling during the safety assessment of performance-based fire safety design. The main objective of this study is to determine the activation temperature and the response time index (RTI) of a fixed heat detector, which are the main input factors of a fixed-temperature heat detector applied to the fire dynamics simulator (FDS), a typical fire model. Therefore, a fire detector evaluator, which is a fire detector experimental apparatus, was applied, and 10 types of domestic fixed-temperature heat detectors were selected through a product recognition survey. It was found that there were significant differences in the activation temperature and RTI among the detectors. Additionally, the detector activation time of the FDS with the measured DB can be predicted more accurately. Finally, the DB of the activation temperature and RTI of the fixed-temperature heat detectors with reliability was provided.