• Journal of Digital Convergence
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• v.11 no.10
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• pp.287-294
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• 2013

This study were proposed for the promotion policy on public confidence in nuclear power recovery schemes. To this end, the existing survey and secondary data review and public distrust of nuclear power plant safety issues were raised. In addition, the meta-analysis data were analyzed by using. Promote public confidence in nuclear power plants recovered three major policy presented. First, the nuclear power plant for the economical / safety communication strategy, short term / long term in terms proposed. Second, strengthen the nuclear power plant reliability and short-term communication strategy / long term in terms proposed. Finally, Korea Hydro & Nuclear Power's long-term image building measures proposed. The results of this study Korea's nuclear power plants to increase confidence in the effect is expected to be presented.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.69-75
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• 2005

In order to improve the reliability of high voltage rotating machines and mold transformers, it is necessary to understand the breakdown mechanism and life assessment of the high voltage winding parts. Especially the on-line PD test provides the ability to monitor effects, such as slot discharge, internal discharge, and end-winding discharge without interrupting the electrical machines, this method has been proven the major testing technology. Capacitive couplers have been the most widely used sensors for the on-line partial discharge detection in rotating machines nowadays. This paper deals with the electrical characteristics and long-term reliability of a ceramic coupler(CC), which can be easily mounted into high voltage input terminal part, has been developed and tested to continuously measure PD activity during operating condition. This paper presents electrical characteristics (dielectric loss angle, capacitance, PD inception level, breakdown voltage, and frequency response bandwidth) and long-term life test result of the developed 6.6 kV class on-line ceramic coupling sensor. It was found that this sensor had good electrical characteristics to detect PD activity during the operating condition with its detection frequency band is between several and several tens MHz. Also, the voltage life of the 6.6kV class ceramic coupler was calculated over 60 years.

• Proceedings of the KIEE Conference
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• 2004.11b
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• pp.261-265
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• 2004

This paper proposes a fuzzy dual method for analyzing long-term transmission system expansion planning problem considering ambiguities of the power system using fuzzy lineal programming. Transmission expansion planning problem can be formulated integer programming or linear programming with minimization total cost subject to reliability (load balance). A long-term expansion planning problem of a grid is very complex, which have uncertainties fur budget, reliability criteria and construction time. Too much computation time is asked for actual system. Fuzzy set theory can be used efficiently in order to consider ambiguity of the investment budget (economics) for constructing the new transmission lines and the delivery marginal rate (reliability criteria) of the system in this paper. This paper presents formulation of fuzzy dual method as first step for developing a fuzzy Ford-Fulkerson algorithm in future and demonstrates sample study. In application study, firstly, a case study using fuzzy integer programming with branch and bound method is presented for practical system. Secondly, the other case study with crisp Ford Fulkerson is presented.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.543-545
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• 1995

The purpose of this paper is to determine the proper reliability criteria used in generation expansion planning of electric utilities. In this paper, we tried to combine long-term generation expansion planning and short-term weekly maintenance scheduling program package. We set two scenarios in which the O&M technology of power plants will be improved or not in the future. We performed LOLP sensitivity analysis for each scenario to determine the optimum reliability criteria in the power system operation aspects.

• Korean Journal of Metals and Materials
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• v.49 no.4
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• pp.275-280
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• 2011

This paper focuses on reliability prediction of long-term creep strength for Modified 9Cr-1Mo steel (Gr. 91) which is considered as one of the structural materials of next generation reactor systems. A "Z-parameter" method was introduced to describe the magnitude of standard deviation of creep rupture data to the master curve which can be plotted by log stress vs. The larson-Miller parameter (LMP). Statistical analysis showed that the scattering of the Z-parameter for the Gr. 91 steel well followed normal distribution. Using this normal distribution of the Z-parameter, the various reliability curves for creep strength design, such as stress-time temperature parameter reliability curves (${\sigma}$-TTP-R curves), stress-rupture time-reliability curves (${\sigma}-t_{r}-R$ curves), and allowable stress-temperature- reliability curves ([${\sigma}$]-T-R curves) were reasonably drawn, and their results are discussed.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.1
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• pp.57-62
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• 2005

Grid-connected photovoltaic (PV) systems were installed and monitored at the field demonstration test center (FDTC) in Korea in October 2002. Before long-term field testing of installed PV systems, the performances of PV components were evaluated and compared through short-term performance tests of each of the PV system components such as power conditioning system and PV module under standard test conditions. A data acquisition system has been constructed for measuring and analyzing the performance of PV systems to observe the overall effect of environmental conditions on their operation characteristics. Performances of PV systems have been evaluated and analyzed not only for component perspective (PV array, power conditioning unit) but also for global perspective (system efficiency, capacity factor, electrical power energy) by review of the field test and loss factors of the systems. These results indicate that it is highly imperative to develop an optimum design technology of grid connected PV systems. The objective of this paper is not only to evaluate and analyze the performance of domestic PV systems application through long-term field testing at FDTC but also to develop evaluation, analysis and optimum technology for long-term stability and reliability of grid-connected PV systems in Korea.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.113-114
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• 2023

This study measured the thickness and speculation coefficient of the coating for existing buildings and calculated the diffusion coefficient of the coating to predict the depth of carbonation through numerical analysis in order to evaluate the impact of the external finish and local environment. As a result, it was possible to predict the short-term and long-term carbonation depth of reinforced concrete buildings coated with coating film with considerable reliability.

• Clinics in Shoulder and Elbow
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• v.27 no.2
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• pp.219-228
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• 2024

Background: Standard open acromioclavicular (AC) stabilization is associated with increased postoperative complications including deltoid injury, infection, tunnel complications, loss of reduction, and wound/cosmetic concerns. Arthroscopy may offer superior visualization and advantages that limit these risks. The aim of this prospective non-randomized study is to evaluate advantages and long-term reliability of arthroscopic AC stabilization. Methods: Thirty-two patients with acute grade III, IV and V AC dislocations underwent arthroscopic AC reconstruction with long-term assessment by clinical AC examination, Simple Shoulder Test, American Shoulder and Elbow Surgeons scores, visual analog scale, Specific AC Score and Quick Disabilities of the Arm, Shoulder and Hand scores. Radiographs verified conservation of initial reduction and presence of coracoclavicular (CC) ossifications. Complications, revision rate, and satisfaction were assessed and compared to the literature. Results: Mean follow-up time was 67.6 months. All clinical outcome scores improved and differences were statistically significant (P<0.001). Initial postoperative radiographs consistently showed complete reduction. Two patients experienced relapse to grade II AC dislocation without clinical implications. In total, 71.8% showed CC ossifications without functional impairment, and in 31.3% concomitant injuries were observed. Reintervention rate was 9.4%, and 96.9% of patients were satisfied with procedure outcomes. Conclusions: Arthroscopic stabilization for acute AC joint dislocations offers satisfactory clinical and radiographic outcomes, and our results show that the arthroscopic technique is reliable in the long run. We report better reduction in maintenance, fewer complications, and similar reoperation rates compared to other techniques.

• Journal of Applied Reliability
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• v.12 no.2
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• pp.91-103
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• 2012

Tubular markers for road safety facilities are used to lead the driver's sight line and separate the lanes on the road. Such tubular markers are usually installed on the road and frequently hit by vehicles, they are accordingly requested to assure the product durability. The traditional evaluation method of tubular markers include only quality tests of the material properties. However, most of consuming agencies in charge of road management at fields have proposed problems on long-term performance of the products hit by vehicles under various weather conditions. Therefore, the objectives of this study are to develop the reliability test methods and equipments to simulate the product failures of tubular markers due to vehicle collision and wheel compression and the delamination and discoloration of reflection sheets attached on the surface of the products under high and low temperatures.

• Proceedings of the KIEE Conference
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• 2006.10a
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• pp.180-181
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• 2006

In this paper, there have been brief review about the important consideration in laboratory planning and construction of the reliability assessment infrastructure including 400 kV, 120 kVA AC test system, which enable to evaluate the HV long-term overcharged withstand performance for spacers using in Gas Insulated Switchgears up to transmission class, Also it is described simply about its trial running of the whole test system and its assessment example. To inform the founded national code, RS C 0084, and the procedure for getting a reliability assessment certificate issued by the government, brief description of the code and summation of test results have been conducted.