• Journal of the Korean Society of Safety
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• v.30 no.5
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• pp.44-51
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• 2015

As the domestic communication industry has been made rapid progresses, the construction of base stations are also expanded yearly from more than 86,000 ones in the year 2005 to over 300,000 ones in 2013. While the new construction and rebuilt works have been rapidly increased, there has been not tried about the analysis as well as the control of hazards for the construction works. This study is conducted to do not only the focus interview for 27 expert groups who are engaged in the construction works and safety, but also the questionnaires for AHP analysis which is suggested by the Korea Occupational Safety and Health Agency for 92 persons who are engaged in the construction works in order to analyze the hazards of construction works for base stations. The high ranked risk works which are acquired from the two methods are fall under installation of antennae, struck by the hand tools and construction materials under installation of antennae, fall during going up and down the steel tower and telegraph poles and the fall by electric shock during the underground cable works. The control for the above hazards are the installation of fall protection equipments, the installation of safety nets for falling objects and the installation of protection equipment of electric shock.

• Journal of the Korean Society of Safety
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• v.21 no.4 s.76
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• pp.102-107
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• 2006

Construction accidents have not decreased in spite of much effort such as new work methods, education and research related to safety works. Specially, many fatal accidents happened in construction works which involve the apartment, building, school, church, hotel, hospital, bank work and the other works. These accidents are mainly caused by unanticipated risk factors. From these reasons, this study researched fatal accidents which happened in construction works during last 13 years($1992{\sim}2004$) and analyzed the input workers and a work period of construction work. According to the input workers and a work period, the results are as following. During 13years($1992{\sim}2004$), the fatal accidents, related to the construction work, were happened to the 1,977 cases. These results were occupied the 21.32% of the total industry accidents. According to the result of the construction, the fatal accident rate of a concrete form work was the highest rate of 16.24% (321 cases) and a temporary work, a steel frame work was the each rate of 12.39%(245 cases), 10.07%(199 cases). Comparing to other work types, the fatal accident rate of those three work types(concrete form work, temporary work, steel work) was represented highly. We surveyed input workers and work period of construction work site. From the result of survey, input workers of a concrete form work were occupied with 13,720. The risk rate of the work type, which was considered input workers and work period, was represented 0.3622(a steel frame work), 0.1142(a temporary work), 0.0782(a tower crane) and 0.0772(a concrete work).

• Journal of the Korean Society of Safety
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• v.35 no.6
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• pp.85-92
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• 2020

Wet Scrubber reacts the incoming pollutant gas with cleaning water (water + absorbent) to absorb pollutants and release the clean air to the atmosphere. Wet scrubbers and packed tower scrubbers using this principle are widely used in businesses that emit acid gases. In particular, in the etching process using hydrochloric acid (HCl), alkaline washing water (NaOH) having a pH of about 8 to 11 is used to absorb a large amount of acid gas. However, These salts are attached to the injection nozzle (nozzle), filling material (packing), and the demister (Demister), causing air pollution, human damage, and inoperability due to clogging and acid gas discharge. Therefore, In this study, an improvement plan was proposed to manage the washing water with pH 3~4 acidic washing water. The test method takes samples from the Wet Scrubber flue measurement laboratory twice a month for 1 year. Hydrogen chloride (HCl) concentration (ppm) was measured, and nozzle clogging and scale conditions were measured, compared, and analyzed through a differential pressure gauge and a pressure gauge. As a result of the check, it was visually confirmed that the scale was reduced to 50% or less in the spray nozzle, filler, and demister. In addition, the emission limit of hydrogen chloride in accordance with the Enforcement Regulation of the Air Quality Conservation Act [Annex 8] met 3 ppm or less. Therefore, even if the washing water is operated in an acidic pH range of 3 to 4, it is expected to reduce air pollution and human damage due to clogging of internal parts, and it is expected to reduce maintenance costs such as regular cleaning or replacement of parts.

• Structural Engineering and Mechanics
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• v.43 no.4
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• pp.545-560
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• 2012

Design codes provide the minimum requirements for the design of code-compliant structures to ensure the safety of the life and property. As for code-exceeding buildings, the requirements for design are not sufficient and the approval of such structures is vague. In mainland China in recent years, a large number of code-exceeding tall buildings, whether their heights exceed the limit for the respective structure type or the extent of irregularity is violated, have been constructed. Performance-based seismic design (PBSD) approach has been highly recommended and become necessary to demonstrate the performance of code-exceeding tall buildings at least equivalent to code intent of safety. This paper proposes the general methodologies of performance-based seismic analysis and design of code-exceeding tall buildings in Mainland China. The PBSD approach proposed here includes selection of performance objectives, determination of design philosophy, establishment of design criteria for structural components and systems consistent with the desirable and transparent performance objectives, and seismic performance analysis and evaluation through extensive numerical analysis or further experimental study if necessary. The seismic analysis and design of 101-story Shanghai World Financial Center Tower is introduced as a typical engineering example where the PBSD approach is followed. The example demonstrates that the PBSD approach is an appropriate way to control efficiently the seismic damage on the structure and ensure the predictable and safe performance.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.48-53
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• 2011

In this study, it is to verify the applicability for a simplified model(IEC61400-2, Design Require-ments for Small Wind Turbines, 2006-03) is the international standard is used to the structural design. In the design process of a wind turbine, the safety of a designed wind turbine is one of the most important factors. The simplified model can be used to determine the design load for small wind turbines. So, this paper has been re-evaluated a small wind turbine design loads that produced already. As a result, the material characteristic value(Rchar) of Blade, Rotor shaft and the tower are $90E6[N/m^2]$, $441E6[N/m^2]$ and $94E6[N/m^2]$. Therefore, the value of the applied safety factor to each part of the survival probability of 95% are satisfied.

• Journal of the Korean Society of Safety
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• v.37 no.6
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• pp.25-31
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• 2022

In this study, the spill and leak system is developed to provide real-time remote monitoring of industrial complexes where chemical accidents have been occurring every year. The spill and leak monitoring system uses IR-RCD equipment mounted on a 70m-high steel tower to detect chemical substances, thereby detecting chemical accidents such as leaks, fires, and explosions in real time. If IR-RCD equipment can actually detect chemical substances at a long distance, accurate and rapid initial response can be expected. Therefore, in order to confirm that IR-RCD equipment can detect chemical leakage accidents occurring at a long distance, acetone was selected as the experimental substance and a detection experiment was designed. The experiment was conducted using the acetone pool evaporation method at the wharf which was located 1.5 km away from IR-RCD equipment, and it was confirmed whether IR-RCD equipment could detect acetone in real time through the control monitor.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.12 no.4
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• pp.253-265
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• 2014

Nuclear education & training is an important issue for sustainability of nuclear energy and the safety of the nuclear power plant. The purpose of this paper is to present policy initiatives for establishment of the national nuclear education & training system. It analyzed current status of nuclear manpower and nuclear education & training systems of Korean nuclear organizations and government strategic plans for nuclear manpower education & training. The features of the current nuclear education & training in Korea are institutional diversification and decentralization in Industry-University-Research system. However, linkages and cooperation systematically integrated between institutions are very weak. In addition, duplicated education & training programs and resource allocation, and the resultant inefficiency have been raised as a problem. Therefore, this paper proposed the national nuclear education & training system model as a macro policy initiatives and construction of control tower that manage and adjust overall nuclear education & training.

• Korean Security Journal
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• no.34
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• pp.279-311
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• 2013

This study is to explore the development of Korean National Emergency Management System. For the study's purpose, the concept of Emergency, Emergency Management and the existing system and related laws of National Emergency Management have been reviewed. In South Korea, the concept of National Emergency Management contains the variety concept of emergency management; safety management, security management, risk management and disaster management etc. and sometimes using them interchangeably. In addition, there are several laws related to emergency management, making different agencies managing inter-related emergency without nationalized coordination and control tower that results in ineffective management of national emergency. This study attempts to clarify the concept of national emergency and to suggest the necessity of National Integrated Emergency Management System(IEMS). Then, it suggests existing system and related laws's integrate for the development of South Korean National Emergency Management System.

• Journal of Environmental Health Sciences
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• v.40 no.2
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• pp.127-136
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• 2014

Objectives: This study was conducted to investigate the removal of high odor concentration from swine wastewater treatment facility by full scale biofilter using liquid with deodorant mixed with earthworm cast and distillery sludge. Methods: The supply of the culture liquid to the microorganism on the media in the biofilter increases the activity and growth of biomass. The experimental equipment was biofilter tower with treatment capacity of 90 m 3/min. The experimental conditions included gas flow of $60m^3/min$, retention time of 20 sec, and gas/liquid ratio of 67. Results: With changing season from winter to summer, the inlet odor concentration of ammonia increased from 2.5 ppm to 29 ppm, and of hydrogen sulfide from 21 ppm to 91 ppm, respectively. The odor treatment system with biofilter using the culture liquid was stable when the high loading rate increased and showed excellent removal grade with an average of 96.7% for ammonia, and an average of 93.7% for hydrogen sulfide. The pH and SCOD in the recirculating culture liquid near the bottom of the biofilter tower decreased with operation time, but its influence on the odor removal rate was negligible, because the organic matter (SCOD) was replaced by some culture liquid supplied 2-4 times per day. Conclusions: The biofilter using culture liquid could successfully remove high odor concentration which was generated from swine wastewater treatment facility.

• Smart Structures and Systems
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• v.26 no.4
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• pp.435-449
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• 2020

To effectively extract the vast wind resource, offshore wind turbines are designed with large rotor and slender tower, which makes them vulnerable to external vibration sources such as wind and wave loads. Substantial research efforts have been devoted to mitigate the unwanted vibrations of offshore wind turbines to ensure their serviceability and safety in the normal working condition. However, most previous studies investigated the vibration control of wind turbines in one direction only, i.e., either the out-of-plane or in-plane direction. In reality, wind turbines inevitably vibrate in both directions when they are subjected to the external excitations. The studies on both the in-plane and out-of-plane vibration control of wind turbines are, however, scarce. In the present study, the NREL 5 MW wind turbine is taken as an example, a detailed three-dimensional (3D) Finite Element (FE) model of the wind turbine is developed in ABAQUS. To simultaneously control the in-plane and out-of-plane vibrations induced by the combined wind and wave loads, another carefully designed (i.e., tuned) spring and dashpot are added to the perpendicular direction of each Tuned Mass Damper (TMD) system that is used to control the vibrations of the tower and blades in one particular direction. With this simple modification, a bi-directional TMD system is formed and the vibrations in both the out-of-plane and in-plane directions are simultaneously suppressed. To examine the control effectiveness, the responses of the wind turbine without control, with separate TMD system and the proposed bi-directional TMD system are calculated and compared. Numerical results show that the bi-directional TMD system can simultaneously control the out-of-plane and in-plane vibrations of the wind turbine without changing too much of the conventional design of the control system. The bi-directional control system therefore could be a cost-effective solution to mitigate the bi-directional vibrations of offshore wind turbines.