• Earthquakes and Structures
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• v.24 no.2
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• pp.141-153
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• 2023

The presented paper considers infill masonry walls' influence on the seismic reliability of precast concrete frames. The recent Bojnord earthquake on May 13th, 2017 in Iran (MW 5.4) illustrated that the infill masonry walls play a crucial role in the damage extent and life safety issues of inhabitants in the precast concrete buildings. The incremental dynamic analysis (IDA) approach was used to determine the fragility curves of the represented damaged precast frame. Then, by integrating site hazard and structural fragilities, the seismic reliability of the represented precast frame was evaluated in different damage limit states. Additionally, the static pushover analysis (SPA) approach was used to assess the seismic performance assessment of the precast frame. Bare and infilled frames were modeled as 2D frames employing the OpenSees software platform. The multi-strut macro-model method was employed for infill masonry simulation. Also, a relatively efficient and straightforward nonlinear model was used to simulate the nonlinear behavior of the precast beam-column joint. The outputs show that consideration of the masonry infilled wall effect in all spans of the structural frame leads to a decrease in the possibility of exceedance of specified damage limit states in the structures. In addition, variation of hazard curves for buildings with and without consideration of infilled walls leads to a decrease in the reliability of the building's frames with masonry infilled walls. Furthermore, the lack of infill walls in the first story significantly affects the precast concrete frame's seismic reliability and performance.

• Journal of the Korean Society of Safety
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• v.14 no.2
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• pp.11-18
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• 1999

Proper fatigue life prediction procedures are needed for mechanical structures which requires high durability and reliability. In this paper, a fatigue life prediction procedure has been developed for predicting fatigue life of moving structure under variable loadings. The developed procedure was efficiently applied for a fatigue life calculation of a container crane. Especially, the procedure is useful for safety assessment by computer simulation. A computer program was developed for fatigue life assessment by adopting the forementioned procedure.

• Journal of the Korean Society of Marine Environment & Safety
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• v.5 no.2
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• pp.87-97
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• 1999

This study is concerned with developing a hybrid heuristic algorithm for solving the redundancy optimization problem which is very important in system safety, This study develops a HH(Hybrid Heuristic) method combined with two strategies to alleviate the risks of being trapped at a local optimum. One of them is to construct the populations of the initial solutions randomly. The other is the additional search with SA(Simulated Annealing) method in final step. Computational results indicate that HH performs consistently better than the KY method proposed in Kim[8]. Therefore, the proposed HH is believed to an attractive to other heuristic methods.

• Proceedings of the Safety Management and Science Conference
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• 2005.11a
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• pp.291-299
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• 2005

Even though, the recent management innovation techniques: The 'Six-Sigma' and the 'BSC (Balanced Score Card)' are introduced to many different companies and are used very effectively. Based on the company's substantial and unique characteristics, the quality and the strategies on management are showing the reliability limits in applications in the company. Therefore, the Integrated Management System is presenting a model for stable application of the activity in the Six-Sigma based on the theoretical notions of the BSC.

• Journal of the Korean Society of Systems Engineering
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• v.11 no.1
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• pp.49-54
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• 2015

The RAMS Process is the Internationally required activity to secure Reliability, Availability, Maintainability, and Safety of system which will be acquired as customer requirements. The importance are situations that have been growing gradually. Specially, When developing railway system, the needs of customer about RAMS Process has been being proposed in a variety of railroad business. Through this paper, It introduces the international standards described the RAMS Process and also presents the requirements that should have to comply with it. Furthermore, the necessary activities to get certificate of a Railway system are suggested and not only the various acquisition cases of certificate but also lessons learned by cases in the field of railway signalling system are presented.

• Proceedings of the KSR Conference
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• 2000.11a
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• pp.602-609
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• 2000

This study is concerned with analysis and reliability evaluation of LV circuit in Cab Cubicle system which controls train to keep safety in High Speed Train. LV circuit is operated with diagnosis system as safety system. In this paper, we suggest a design and an implementation method to analyze LV circuit or trace fault area in LV circuit. This simulator uses 28 package modules and examines input and output by equations. So, user can trace where is fault area. The implemented system can be expected to be useful for long term test and evaluation of circuit in high speed train systems. We expect reduction to diagnosis area or repair time by this simulator.

• Proceedings of the KWS Conference
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• 2006.05a
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• pp.94-96
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• 2006

Recently, steel structures have been increasing because of its brilliant features. In general, cracks and corrosion are produced due to the numerous environmental factors in steel structures. However, the validity of repair method for the damaged steel structures has not been fully verified because of its lack of safety and reliability after application. Moreover, repair method by welding inevitably involves cutting and welding processes and reliability for the safety during the processes has net been established yet. Therefore, this study carried out experiments on the fatigue strength of repair welded joints of old steel bridge to investigate the fatigue characteristics in the repair welded joints. Fatigue tests were conducted by 250kN capacity MIS with the frequency of 5Hz under amplitude loading. From the results, it is known that fatigue strength grade of the repair welded joints was satisfied with C grade which specification requires.

• Journal of the Korean Society of Safety
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• v.15 no.4
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• pp.150-156
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• 2000

In this paper, the human error contributions to the system unavailability are calculated and compared to the mechanical failure contributions. The system unavailability is a probability that a system is in the failed state at time t, given that it was the normal state at time zero. It is a function of human errors committed during maintenance and tests, component failure rates, surveillance test intervals, and allowed outage time. The THERP (Technique for Human Error Rate Prediction), generally called "HRA handbook", is used here for evaluating human error rates. This method treats the operator as one of the system components, and human reliability is assessed in the same manner as that of components. Based on the calculation results, the human error contribution to the system unavailability is shown to be more important than the mechanical failure contribution in the example system. It is also demonstrated that this method is very flexible in that it can be applied to any hazardous facilities, such as gas valve stations and chemical process plants.ss plants.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.1-9
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• 2000

In this paper, a design method of fault-tolerance is presented for the nuclear digital control systems composed of software and hardware. As a quantitative design method measure of fault-tolerance, we used Reliability, Availability and Safety. To implement the proposed fault-tolerance, a prototype system has been devised for the digital control systems and a quantitative method of 'Markovian Model' is applied. The results provide the appropriate degree of redundancy and diversity, and fail-safe.

• Journal of the Korea Safety Management & Science
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• v.19 no.1
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• pp.245-255
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• 2017

This paper is a study to estimate the noise generated by fluid around each machine in the basement and basement facilities that accept major noise factor, pump fluid mechanical equipment installed to evaluate the impact on the real working environment. In particular, the review of the reliability of complementary information and reliability predict the natural frequency for generating a maximum strain when the vibration analysis, and intended to ensure that the design to avoid a natural frequency of the structure, on the basis of the this analysis result to the subject a real building.