• Journal of the Korea Construction Safety Engineering Association
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• s.37
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• pp.74-83
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• 2006

As there are more accidents which are more serious in construction site than other industries, it needs the safety management system to be SLIM on the same time, there are still lots of difficulties to prevent those accidents exactly, so it also needs a safety supervision team to prevent the accident, unsafe operation and condition before happening, which is also called as a Man-to Man safety management method. The range of the job site in one personnel's management is very big and large, so it needs the personnel to deep watch the safety operation and prevent any unsafe/fire accidents; the personnel also should find out the unsafe points in the job site, and carefully supervise the dead angle site, then support the totally safety management POINT and realize the ZERO accident.

• Journal of Information Technology Applications and Management
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• v.15 no.2
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• pp.67-82
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• 2008

Risk that breed large size disaster is happening variously for cause at social. natural a management. Incidence and damage scale are trend that increase rapidly than past. In these circumstance, to keep operational continuity of organization, area, society, risk management action that establish systematic counter measure estimating and analyze occurrence possibility and expectation damage of risk is essential indispensable issue and the best countermeasure. Risk management action does by main purpose establish optimum disaster reduction countermeasure. To deduce various countermeasure, process that estimate and analyze occurrence possibility and expectation damage of risk is essential indispensable issue. Therefore, this paper studies process design that can presume risk occurrence frequency and damage scale through distribution of probability.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1330-1331
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• 2011

The on-grid distributed power system operated antiislanding due to the momently voltage sag of the power system, fault and etc. According to the 'Dispersed Generations in Distribution Systems Connection Technology Standard', the utilizable time ratio of PCS is low because of being put into in the steady state of the power system after 5 minutes. In this paper, the output characteristic is optimized with the hybrid system consisting of the wind system and PV system. And energy of hybrid system is supplied to the power system. Also, DVR function was applied to PCS to compensate the voltage sag frequently happening for a power system. The control performance of the proposed hybrid PCS is analyzed and simulated using PSIM to validate the system performace.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1255-1261
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• 2004

A variational approximation procedure is introduced to study the contact stresses between a representative asperity and a feature generally happening in superfinishing processes such as FAM. After a description of the model under consideration is presented, a system of governing equation for the model is derived fullowed by the assumptions made in order to make progress in model development. Final computation is made to evaluate contact stresses on an elastic asperity tip in small scale in size and a computer simulation is performed for detailed surface profile variations on a representative feature. Numerical results are presented along with a discussion of the conclusions that can be drawn from this analysis.

• Tribology and Lubricants
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• v.21 no.6
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• pp.289-295
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• 2005

Most machine element, such as gears and bearings, are operated in the mixed lubrication region. Contact between two asperities has an effect on machine life by increasing local pressure. To estimate fatigue life exactly, asperity contact should be considered as a factor of fatigue life because this happening produce friction, abrasion and make flash temperature. In this paper, asperity contact is considered as a result of film breakdown when lubricant pressure is not enough to separate two asperities. Contact pressure is calculated to asperity overlap region and added to lubricant pressure. For this model, numerical procedure is introduced and the result on surface roughness and velocity for wheel bearing is presented. Results of EHL analysis for wheel bearing show that asperity contact is occurred at the edge ofEHL conjunction where has a insufficient lubricant pressure to separate two surface.

• Journal of Korea Society of Industrial Information Systems
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• v.17 no.7
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• pp.101-110
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• 2012

These days, the environment of IT development goes through converging with various industries and technologies. Also, it accelerates to pioneer new markets and develop new technologies. This trend becomes one of the most important factors to explore new national growth engines in Korea. Thus, this research examines current trends of IT convergence in Korea. The strategic characteristics of IT convergence in overseas are briefly explained for comparing purpose. The governmental strategies or efforts regarding the IT convergence have been surveyed. Some example convergences of LG, Samsung, and POSCO as major IT industries in Korea have been introduced. It also identifies several buzz concepts in this field. The study aims to provide an insight about the activities that are happening in the field of IT convergence in Korea. Finally, the findings through the research have been summarized.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.19 no.4
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• pp.117-122
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• 2011

EMSS is the organic system offering quick and efficient transfer and treatment for those who need an emergency service. For EMS aviation operation is the important transportation for the common benefits. There are several types of aviation operation. Among the different types of the operations, helicopter operation is very common because it is free from any locations. Notwithstanding the benefit, various types of EMS helicopter accidents and incidents are occurred because of its poor operation condition. In South Korea, even though so much effort was put to decrease the accidents rates, there are still many accidents happening by fire helicopters and the forest service helicopters. Therefore, in order to regularize the EMSH operation, measures for the aviation safety have to be prepared. This research is, related to the EMSH, focused on the suggestion of safety measure for the EMSH in Korea based on the accidents analysis in various countries.

• Journal of the Korean Society of Safety
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• v.27 no.5
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• pp.135-140
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• 2012

In this study, the behavior of pollutant was calculated at Paldang reservior according to several scenarios of the accidental water pollution by means of the numerical models for forecasting water quality. Also managemental plans for situation of the accidental water pollution happening at Paldang watershed were simulated. According to the simulating results, a plan of increase of discharge at Cheongpyeong dam reduced the peak concentration of pollutants, whereas extended the time for stopping water intake. Another plan, drop of water elevation at Paldang dam, decreased seriously the time for stopping water intake although there were a little effect to decrease the peak concentration. Thus it was concluded that appropriate combinations of the plans for the increase discharge and the dropping water elevation should be used to deal with the accidental water pollution at Paldang watershed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.8
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• pp.42-49
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• 2012

Grid-connected photovoltaic generator system requires high performance PCS(Power Conditioning System) according to the standard of 'Distributed Generation Grid-Connected Technology Standards'. This paper presents the MPPT control method which improves output efficiency through fast tracking to the maximum power point of PV and a reduced self-excited vibration. Secondly, in this paper DVR function was applied to PCS to compensate the voltage sag frequently happening for a power system. The proposed PCS control is analyzed and compared to conventional PCS operating characteristic, the various insolation and loads, and voltage sag condition through PSIM tool. It proves the utility.

• Journal of Advanced Navigation Technology
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• v.15 no.6
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• pp.1008-1014
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• 2011

In this paper, multi-band fractal microstrip patch antenna which is possible for WLAN band and WiMax band is designed and made. For multi-resonance of developed antenna, resonance frequency, impedance matching, polarity and reflection pattern can mad perfectly, then to make satisfied multi-independent frequency three kind of half circle fractal patch is inserted. In the situation continuously happening half circle in designed structure, antennas one of half-circle band is shown.