• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.6
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• pp.458-464
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• 2020

Calibration of load-resistance factors for the limit state design of perforated caisson breakwaters are presented. Reliability analysis of 12 breakwaters in nationwide ports was conducted. Then, partial safety factors and load-resistance factors were sequentially calculated according to target reliability index. Load resistance factors were optimized to give one set of factor for limit state design of breakwater. The breakwaters were redesigned by using the optimal load resistance factor and verified whether reliability indices larger than the target value. Finally, some load-resistance factors were proposed by changing target reliability index.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.7-16
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• 2013

As workplace incidents has been being declining in Korea, there is criticism of the effectiveness of occupational safety policy implementation. It is unknown that which policy target group needs to be targeted to yield effective injuries prevention. The purpose of this paper is to analyze and reveal the policy intervention group with a high priority in terms of industrial incident prevention and the related investment cost. A Policy Priority Model(PPM) is composed of 6 indicators regarding influences of both the incident reduction and the cost reduction. Z-score analyses are used to confirm the high policy priority area or policy target group. Overall, workplace with worker below 50 persons, construction site with the sales of more than a hundred million won, workplace with relatively small percentage of female employees and relatively higher percentage of older worker should be prioritized to reduce workplace injuries. This paper provides an analytic way that can be used to decide the policy priority workplace in order not only to reduce work-related injuries&illnesses and the related investment cost but to further lessen the related societal costs.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.272-279
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• 2016

Purpose: In order to fulfill the RAMS (Reliability Availability Maintainability and Safety) requirements in Korean railway systems, specific target metrics should be measured and met the requirements when ordering a new system. This paper presents a procedure to predict and demonstrate the availability, maintainability and safety of subway elevators, escalators and PSD (platform screen doors) systems. Methods: The system manufacturer predicts availability and maintainability with lab and field tested data. After installation, availability and maintainability are demonstrated based on the actual operational data. The data was collected from the FRACAS (Failure Report and Corrective Action System). Results: Methods and process of assessing and analyzing the availability, maintainability and safety are presented for elevating services and PSD systems. The data obtained through the actual operation of the equipment is analyzed and maintained to predict the RAMS based on the component and system level failure data acquired. Conclusion: This study presented an application using IEC 62278 and operational data which can be used in the design and development stage to achieve the RAMS target value of the subway elevators, escalators and PSD systems.

• Journal of Navigation and Port Research
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• v.43 no.5
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• pp.310-319
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• 2019

With the recent increase in the volume of liquid cargo transportation, there is a need for STS( Ship To Ship) globally. In the case of the STS mooring, the safety assessment should be conducted according to other criteria because mooring is different from the general mooring at the quay, but there is no separate standard in Korea. Thus in this study, STS mooring simulation and sensitivity analysis using OPTIMOOR program, the numerical analysis program, was conducted to identify the characteristics of the STS mooring. The target sea modeled the Yeosu port anchorage in Korea and the target ship was selected as the case of VLCC (Very Large Crude Oil Carrier)-VLCC. Through the numerical simulation and sensitivity analysis, the characteristics of STS mooring were identified. Also based on these results, we focused on establishing the standard for STS mooring safety assessment. Numerical simulation results show that the STS mooring safety can be changed according to a ship's cargo loading condition, pre-tension of mooring line, sea depth, encounter angle with the weather, and the weather condition. Additionally, the risk matrix is prepared to establish the safe external force range in the corresponding sea area. This result can be used to understand the mooring characteristics of STS and contribute to the revision of mooring safety assessment criteria.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.1
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• pp.91-102
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• 2014

Objectives: This study was performed in order to devise a procedure for supplementing the Special Management Materials in the Occupational Safety and Health Act and recommend candidate materials. The results are expected to be used as fundamental data for classification and criteria necessary to manage Special Management Materials in workplaces. Also, they are expected to be used as a basis for selecting target materials to nominate as additional Special Management Material. Methods: We investigated the selection standards for candidates and review ranges of data sources to nominate Special Management Materials. The substances classified as GHS(Globally Harmonized System of classification and labeling of chemicals) category 1A(known to have carcinogenic potential and reproductive toxicity for humans) or 1B(presumed to have carcinogenic potential and reproductive toxicity for humans) carcinogens and reproductive toxicants among the Controlled Hazardous Substances of the Regulation on Occupational Safety and Health Standards and substances with OELs(Occupational Exposure Limits) were inspected as the candidates for Special Management Materials. Conclusions: A seven-step procedure for selecting candidates to designate as Special Management Materials was suggested, including the setting of target chemicals for evaluation, classification of CMR(Carcinogens, Mutagens or Reproductive toxicants) by GHS classification and criteria, suggestion and selection of the candidates, and more. This study recommends 58 chemicals as qualified candidates to supplement the Special Management Materials.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.191-201
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• 2010

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

• Journal of the Korean Society of Safety
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• v.32 no.2
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• pp.34-37
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• 2017

In recent emerging industry, Display field becomes bigger and bigger, and also semiconductor technology becomes high density integration. In Flat Panel Display, there is an issue that electrostatic phenomenon results in fine dust adsorption as electrostatic capacity increases due to bigger size. Destruction of high integrated circuit and pattern deterioration occur in semiconductor and this causes the problem of weakening of thermal resistance. In order to solve this sort of electrostatic failure in this process, Soft X-ray ionizer is mainly used. Soft X-ray Ionizer does not only generate electrical noise and minute particle but also is efficient to remove electrostatic as it has a wide range of ionization. X-ray Generating efficiency has an effect on soft X-ray Ionizer affects neutralizing performance. There exist variable factors such as type of anode, thickness, tube voltage etc., and it takes a lot of time and financial resource to find optimal performance by manufacturing with actual X-ray tube source. MCNPX (Monte Carlo N-Particle Extended) is used for simulation to solve this kind of problem, and optimum efficiency of X-ray generation is anticipated. In this study, X-ray generation efficiency was measured according to target material thickness using MCNPX under the conditions that tube voltage is 5 keV, 10 keV, 15 keV and the target Material is Tungsten(W), Gold(Au), Silver(Ag). At the result, Gold(Au) shows optimum efficiency. In Tube voltage 5 keV, optimal target thickness is $0.05{\mu}m$ and Largest energy of Light flux appears $2.22{\times}10^8$ x-ray flux. In Tube voltage 10 keV, optimal target Thickness is $0.18{\mu}m$ and Largest energy of Light flux appears $1.97{\times}10^9$ x-ray flux. In Tube voltage 15 keV, optimal target Thickness is $0.29{\mu}m$ and Largest energy of Light flux appears $4.59{\times}10^9$ x-ray flux.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.562-568
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• 2014

This study is safety assessment standard for advanced surface movement guidance control system (A-SMGCS) and case study of the past research project. A-SMGCS providing routing, guidance and surveillance for the control of aircraft and vehicles in order to maintain the declared surface movement rate under all weather conditions within the aerodrome visibility operational level while maintaining the required level of safety. Recently, in korea and europe are developing A-SMGCS system for the safety control of the airport movement area. In safety oriented industry such as aviation that it is necessary to verify and ensure for operating system. In this case study, analysis of safety assessment standard for verified A-SMGCS target level of safety (TLS) and previous developed A-SMGCS research project.

• Journal of the Korean Society of Safety
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• v.31 no.1
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• pp.7-12
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• 2016

This study first focuses on the quantitative evaluation of both compulsory and voluntary safety certification of industrial machines and devices. Based on the results of statistical analysis, effectiveness of those safety certifications were confirmed. In order to reduce both the frequency and the strength of industrial accidents associated with industrial machines and devices, major target of safety regulations needs to be shifted from users to manufacturers. Adjustment of industrial machines and devices which are subject to compulsory safety certification and implementation of risk assessment are further suggested. As for the voluntary certification, reestablishment of the concept of voluntary safety certification and balance between compulsory and voluntary certifications is discussed. Voluntary safety certification is further suggested as a mean to manage safety of industrial machines and devices which are not subject to any safety regulations.

• The Korean Journal of Pesticide Science
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• v.11 no.1
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• pp.32-37
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• 2007

The study was carried out to establish buffer zone for the protection of the non-target organisms by aerial pesticide application. The two pesticide combination of 3-way tank-mixing of three pesticides for aerial application, ferimzone tricyclazole SC + BPMC EC + validamycin-A SL and hexaconzole EC + isoprothiolane EC+phenthoate EC were selected for the simultaneous control of key pests on paddy rice as blast, sheath blight, brown planthopper and moth. Aquatic organisms including killifish and loach in the paddy field and nearby water reservoirs were not affected by aerial application of the pesticides. However, all the water flea were killed, when they were exposed 10 m from the aerially sprayed site, while the water flea exposed in 30 m away from the site were not affected. Honeybees within 50 m in the wind direction and 20 m in the opposite wind direction showed a mortality of $7{\sim}100%$. Residues concentration of the pesticides in paddy water were not detectable level after six days from aerial application. Drifting distance of aerially sprayed droplet from the target area was within 30 m in the wind direction and 20 m in the opposite direction. Consequently, it was the buffer zones in the aerial pesticides application for the protection of the non-target organisms should be at least 50 m for aquatic organisms and 100 m for honeybees.