• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.310-323
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• 2023

The k-eigenvalue neutronics/thermal-hydraulics coupling calculation is a key issue for reactor design and analysis. Jacobian-free Newton-Krylov (JFNK) method, featured with super-linear convergence rate and high efficiency, has been attracting more and more attention to solve the multi-physics coupling problem. However, it may converge to the high-order eigenmode because of the multiple solutions nature of the k-eigenvalue form of multi-physics coupling issue. Based on our previous work, a modified JFNK with a line search method is proposed in this work, which can find the fundamental eigenmode together with thermal-hydraulics feedback in a wide range of initial values. In detail, the existing modified JFNK method is combined with the line search strategy, so that the intermediate iterative solution can avoid a sudden divergence and be adjusted into a convergence basin smoothly. Two simplified 2-D homogeneous reactor models, a PWR model, and an HTR model, are utilized to evaluate the performance of the newly proposed JFNK method. The results show that the performance of this proposed JFNK is more robust than the existing JFNK-based methods.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.293-301
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• 2024

Purpose: Ministry of Environment statistics reveals more than 132 fire·explosion accidents in South Korea between 2014 and 2023. Among them, fire and/or explosion accidents are very impactive in their scale and consequence. This study aims to suggest a new method of reasonable way to calculate the ventilation rate of indoor facility handling hazardous chemicals based on their inflammability. Method: A new method to calculate the ventilation rate is based on the physicochemical properties of the chemicals handled, which is more reasonable compared with the current regulation based only on the floor area of the facility. Result: Considering the physicochemical properties, 178 chemicals based on their inflammability were studied and 168(94%) met the criteria for the current regulation. Some materials have been shown to require too much or too little ventilation rate. Conclusion: Through this study, a reasonable method of calculating the required ventilation rate was proposed. This should be applied to ensure the safety of workers to deal chemicals.

• Journal of Korean Society for Quality Management
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• v.49 no.2
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• pp.127-143
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• 2021

Purpose: Smart Safety Living Lab is a Living Lab facility, constructed and operated by KITECH in Korea, to support the user experience(UX) evaluation, planning and certification of smart safety products and services. The purpose of this study is to develop a UX evaluation methodology that accommodates the characteristics of the Living Lab and smart safety products and services for a systematic and efficient UX evaluation in the Smart Safety Living Lab. Methods: A generic model of UX evaluation was first derived based on a review of related literature. Then, the generic model is revised to accommodate the characteristics of the Smart Safety Living Lab and smart safety products and services, resulting in the UX Evaluation Methodology for Smart Safety Living Lab (SSLL-UXEM). Results: The developed SSLL-UXEM consists of a structured process for UX evaluation, a guideline for conducting each step of the process, and a set of forms for recording the major evaluation results in each step. Conclusion: SSLL-UXEM can help to enhance the efficiency of the UX evaluation process and the consistency of the UX evaluation results. SSLL-UXEM is also expected to serve as a basis for UX evaluation in various living lab environments in the future.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.3
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• pp.261-267
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• 2015

A support system which allows operator to check the condition of a vessel and to warn the sea risk in order to prevent accidents of leisure boats, is required. Therefore, this paper proposes a navigational safety support system to ensure the safety of vessels by monitoring and managing the status of those ships. In developing a system process, each developed equipment is integrated and verified whether the functional, compositional and operational algorithms are working properly according to the designed object.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.95-103
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• 2019

Safety and welfare of forestry is very poor because of poor working environment, decreasing workforce and budget, and aging. These have brought many accidents and casualties. The accident rate in the field of forestry were about 2.83 times higher than average of an entire industry and mortality rate were 1.84 times higher than it. The most reason among the mortality accident was caught in, under or between objects and struck by objects. In analysis of 60 serious accident cases, the number of occurrence s of caught in, under or between objects and struck by objects were the highest. We suggest education, engineering, environment, and enforcement methods which is first aid education and emergency response system, equipment of combined IoT technologies and sensors, and certification and career program on the basis of the results.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.499-502
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• 2009

Supply of electric power and electricity safety for whole system and network are essential element. Electricity safety technology need rating for product and research about certification as product development that is done cotton flannel mixed with development of u-IT technology consists. Study on serve to develop electricity safety integration supervision system to apply product to u-City electric power appliance and cotton flannel mixed of u-IT appliance, Connection badness sensing instrument made device built-in electric power IT cotton flannel mixed in outlet that is used most in electric power appliance terminal. Using sensor on ZigBee, RFID performance estimation of communication and module for remote safety check of electricity safety integration supervision system. A performance experiment and estimation in PD, Arc detection diagnosis system and certification KS, electricity safety about product that get fitness finding.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.26-32
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• 2021

The antenna is mounted on the vehicle and operated, so its components must be able to withstand the shock that may occur while driving. In this study, the stability of antenna mounted on the vehicle is verified through the connection between modal analysis and transient analysis. The shock data used was taken from MIL-STD-810H, METHOD 516.8. As a result of the analysis of antenna, the maximum equivalent stress 169.49MPa and minimum margin of safety 2.31 has occurred on the bracket of antenna. Thus, it was found that the antenna has enough stability during the operation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.6
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• pp.44-50
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• 2021

This study analyzed the stability of antenna equipped on vehicles by the link of modal analysis and random vibration analysis with the vibration data of MIL-STD-810H, METHOD 514.8. As a result of the random vibration analysis of antenna, the maximum equivalent stress 41.9MPa and minimum margin of safety 8.37 was generated in the bracket of antenna by the vertical direction vibration. Thus, it was found that antenna has enough stability during the operation.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.4_2
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• pp.637-644
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• 2020

Because suicide accidents sometimes were happened in grand bridges over rivers or sea water recently, it will be necessary that prevention measures be made preparation in advance from now on. Additional safety facilities must be needed in addition to existing safety facilities in such a way as this prevention measure. In order to make cable-stayed bridge safe on wind for additional safety facilities, main girder models with added safety facilities for wind-tunnel tests was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel test results. From the wind experiments, force coefficients of main girder with added safety facilities were assessed, and it is known that there are little possibility of galloping and rotation of steel main girder. Finally, from the wind resistant analyses, it was concluded that wind-resistant safety of cable-stayed bridge was secured on wind speed 60.6m/sec.

• Journal of the Korean Society of Industry Convergence
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• v.25 no.4_2
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• pp.587-594
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• 2022

In the 2000s, a lot of cable-type grand bridges are being built in consideration of economic aspects such as the reduction of logistics costs and the distribution of traffic volume due to rapid economic development. In addition, because the recently installed grand bridges are designed in an aesthetic form that matches the surrounding environment as well as the original function of the road bridge, and serves as a milestone in an area and is used as an excellent tourism resource, attracting many vehicles and people, there is an urgent need for a safety structure that can ensure the safety of not only vehicles but also people. In order to make cable-stayed bridge safe on wind for additional five safety structures, main girder models with and without safety structures for wind-tunnel experiments was made, and wind tunnel experiments was carried out to measure aerodynamic force coefficients. Also, wind-resistant analyses of 3D cable-stayed bridge were performed on the basis of wind-tunnel experiment results. From the wind tunnel experiments for the aerodynamic force coefficients of main girder with five safety structures and the wind resistant analyses of cable-stayed bridge without safety structure and with safety structure, it was concluded that the best form of wind-resistant safety was shown in the order of mesh, standard, bracing, hollow, and closed type. And wind-resistant safety of cable-stayed bridge with hollow and closed type on design wind speed 68.0m/sec was not secured. Finally, as five safety structures are installed, maximum rate of stress increments was shown in the order of steel main beam, steel floor beam, concrete floor beam and cables.