• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.171-176
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• 2022

The communication signal for quick cut-off specification is defined as "design to support fast cut-off requirements of all applicable photovoltaic(PV) systems" in NEC 2014, NEC 2017 or the corresponding UL standard regardless of the system configuration. On the other hand, if you look at the domestic regulations related to new and renewable energy, the standards, regulations, and guidelines set by each institution are general, or only the parts necessary for the institution are being established and operated. There are many insufficient points to apply these things to photovoltaic facilities, and there are cases where excessive facilities are installed according to the design, inspection standards of supervisors and inspection agencies, and the skill level of inspectors. The internationally accepted IEC standards deal with various facility standards in detail. In each European country, there are separate facility regulations based on IEC. In particular, the performance and safety of devices are dealt with in detail, and in the case of 'NEC Article 690' applied in North America such as the United States, each item is described in detail. Therefore, in this paper, we will look at the details of the PV shutdown technology that is currently used and applied internationally.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.58-65
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• 2012

Various models are currently applied to predict the dispersion of leaked combustible gas and overpressure from a vapor cloud explosion(VCE). However, those models use simple approaches where topography and barriers of anti-leakage facilities and the effects of buildings were not sufficiently taken into considerations. For this reason, this study has proposed the dispersion process of leaked gas, distribution patterns, and flames and overpressure generated from gas explosions in 2D and 3D virtual spaces by reviewing more accurately analyzable computational fluid dynamics (CFD) model by considering various variables including combustion types of leaked substances, geometry of facility, warm currents, barriers, the influence of wind, and others. The CFD analysis results are anticipated to be usefully applied for the risk analysis of explosion and for the risk-based design.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.315-330
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• 2018

A subcritical facility must ensure nuclear criticality safety under all circumstances. For this purpose, it is essential to have a procedure to validate that calculated values do not exceed upper subcritical limit (USL), determined by quantifying the bias and uncertainty. However, there are several validation methodologies of nuclear criticality safety and these can yield different USL. Therefore, it is necessary to analyze the validity of the methodologies to establish one methodology that can provide the most appropriate USL. In this study, two documents, a guide for validation of nuclear criticality safety calculational methodology (NUREG/CR-6698) and a criticality benchmark guide for light water reactor fuel in transport and storage package (NUREG/CR-6361), are compared and analyzed. In particular, the methodology in NUREG/CR-6361 is applied to the USLSTATS code. However, the analysis results show that the methodology in NUREG/CR-6698 is more appropriate, for several reasons. This is applied to decision of USL to design casks using SCALE code version 6.1.

• Tunnel and Underground Space
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• v.23 no.3
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• pp.192-202
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• 2013

The domestic demand of natural gas has increased continuously due to the sudden rise of oil price and regulations on greenhouse gas to global warming. In order to improve the supply security of natural gas market in Korea, the agreement on supply of pipeline natural gas (PNG) in Russia was signed between Gazprom and Korea Gas Corporation in 2008. If the supply plan of Russian natural gas is realized, underground storage facilities would be required in order to balance supply and demand of natural gas because the gas demand is concentrated in the winter. This study investigated the safety of the storage facility in quantitative way considering several design parameters such as gas pressure, depth of the storage cavern, rock condition and in-situ horizontal stress ratio. Two dimensional stress analyses were conducted using axi- symmetry condition to examine the behavior of cavern depending upon suggested design parameters. Results showed that the factor of safety, defined as the ratio of 'shear strength'/'shear stress', was largely affected by the depth, rock class and gas pressure but was insensitive to the coefficient of lateral pressure(Ko).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5558-5565
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• 2012

Roadside barriers are facility for preventing cars from out of path, and 7 classes of barrier are prescribed in criteria of road grades and speed limit, etc. However, overload and overspeed are increased according to improvement of vehicle performance, and falling over frequently occur in vehicle accident related in barriers. Therefore, enhancement of the existing design criteria of roadside barriers is demanded. In this research, vehicle crash simulation was carried out, and the condition for fracture of roadside barriers and vehicle overturn was evaluated in order to verify the defence performance of the barriers, which are SB5 steel barrier and SB6 concrete barrier adapted mainly to highway.

• Journal of Sport and Applied Science
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• v.4 no.3
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• pp.23-28
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• 2020

Purpose: This study sought to explore current status of children's swimming pool in Korea and to generate insights regarding safety management of children's swimming pool. Research design, data, and methodology: The study reviewed literatures including documents of Ministry of Culture, Sports and Tourism and sport facility-related articles. Furthermore, the study collected additional statistics via search engines. Results: First, numbers of swimming pools have been dramatically increased since 2016 and Korea experienced an increase of 37% from 2010 to 2019. Of the 611 indoor swimming pools, most swimming pools are located in Gyeonggi province with 27.7% (n=169). Seoul and Gyeonggi-do have the highest proportion of swimming pools in Korea. Second, in types of swimming pools, 47.6%(n=291) was children's swimming pool which is the highest proportion in the nation. Children's swimming pools are also mostly located in Seoul and Gyeonggi province with 57%. Third, of 372 profit swimming pools, children's pools show the highest number with 78%(n=291). Conclusions: Children's swimming pools are picking up faster than the other types of swimming pool. Yet, safety-related studies are still lack. This provides motivations to produce managerial insights from academia and business sectors. Moreover, more studies of legal issues should be conducted. Implications were discussed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.7
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• pp.1-5
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• 2006

Fixed lighting of public ways for both drivers and pedestrians can create a nighttime environment in which people can see comfortably and can quickly and accurately identify objects on the roadway being travelled. Roadway lighting can improve traffic safety, achieve efficient traffic movement and promote the general use of the facility during darkness. The design of a roadway lighting system involves consideration of visibility, economics, esthetics, safety and environmental conditions. This paper shows estimation of horizontal illuminance and uniformity ratio by actual measurement of roadway lighting at main streets in Jejusi and evaluation of Jejusi roadway lighting conditions for modeling by computer simulation.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.297-304
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• 2010

In the design of advanced light water reactors (ALWRs) and in the safety assessment of currently operating nuclear power plants, it is necessary to evaluate the possibility of experiencing a degraded core accident and to develop innovative safety technologies in order to assure long-term debris cooling. The objective of this experimental study is to investigate the enhancement factors of dryout heat flux in debris beds by coolant injection from below. The experimental facility consists mainly of an induction heater, a double-wall quartz-tube test section containing a steel-particle bed and coolant injection and recovery condensing loop. A fairly uniform heating of the particle bed was achieved in the radial direction and the axial variation was within 20%. This paper reports the experimental data for 3.2 mm and 4.8 mm particle beds with a 300 mm bed height. The dryout heat density data were obtained for both the top-flooding and the forced coolant injection from below with an injection mass flux of up to $1.5\;kg/m^2s$. The dryout heat density increased as the rate of coolant injection increased. At a coolant injection mass flux of $1.0\;kg/m^2s$, the dryout heat density was ${\sim}6.5\;MW/m^3$ for the 4.8 mm particle bed and ${\sim}5.6\;MW/m^3$ for the 3.2 mm particle bed. The enhancement factors of the dryout heat density were 1.6-1.8.

• Culinary science and hospitality research
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• v.14 no.1
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• pp.94-106
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• 2008

This study is conducted to explore the cooks' recognition of culinary environment of school feeding among the cooks working for elementary schools, middle schools, and high schools in the Ulsan district. A total of 200 samples were distributed and 185 samples were collected; among them, 182 valid samples were selected for research. Answers were processed by SPSS 12.0. after data coding. As for factor analysis of culinary environment, three factors were extracted, which are general environment, human environment, and facilities equipment environment. It was found that general environment included ventilation(31.5%), temperature (29.0%), humidity(22.1%) in the order of importance; human environment covered cooperation among cooks (28.1%), the number of cooks(25.7%), and professionalism of cooks in the order of importance; facility equipment environment contained the design and layout of facilities and equipment(29.3%), various safety facilities, and safety device(23.3%) in the order of importance. However, a measure for improving work environment, number of cooks, deterioration of equipment, etc. should be considered.

• Journal of the Korea Safety Management & Science
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• v.8 no.3
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• pp.77-86
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• 2006

After conducting an investigation of a specific workplace, 372 labor workers, who are employed at a certain domestic petrochemical company valve operating and maintenance processing section, were personally questioned about specific work-related ailments. According to the results, 57% of workers who were working in the petrochemical industry have suffered from pain-related musculoskeletal disorders in, at least, more than 1 body part. Specifically, there are more than 28% of workers suffering from pain in more than two body parts. Among the total work population, 18.8 % of workers are assumed to have a high probability of being diagnosed with musculoskeletal disorder. Also, according to the RULA checklist which evaluates environmental improvement conditions of the workplace, 76.7% of workplaces among the inspected areas have high hazardous work factors that are related to musculoskeletal disorder and needs to be improved upon and observed right away or in the foreseeable future. The prior factor has a high correlation and pain rate which is due to an improper work posture. Originally, this improper work posture is caused mostly by ergonomically incorrect facility design. Furthermore, the structure of the workplace does not consider the worker's individual build.