• Electrical & Electronic Materials
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• v.11 no.10
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• pp.32-39
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• 1998

Electrical breakdown strength of paper-oil and polypropylene/film-oil insulation samples was measured under dc, ac and pulsating voltages. The latter was obtained by superimposing ac upon dc volate and provides an attractive method for a simultaneous testing and assessment of the state of insulation of the various parts of HV apparatus in service. The measurements were carried out over a wide range of the pulsation ratio defined as p=Eac/Edc. The results obtained under pulsating voltages follow colsely an experssion which relates the breakdown strength to the sum of arc tangent and arc cotangent function of the parameter p. The study was carried out using dry paper as well as paper containing various degrees of moisture. The presence of moisture showed a pronounced effect upon the breakdown strength which varied with the pulsation parameter p.

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.92-94
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• 2001

This paper investigated the real-time generator swing prediction by some researchers. And the first swing stability assessment based on EAC(Equal-Area Criterion) by using phasor measurement unit is proposed. Also we proposed the multi-swing prediction techniques, which is to estimate system parameters by using least square method / extrapolation with phasor measurement units. And the multi-swing prediction is performed with the estimated parameters. Future works are necessary to verify the proposed approaches in this paper.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.05a
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• pp.1067-1070
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• 2003

The effects of traffic noise are a serious concern in many urban communities throughout the world. Environmental noise at high intensities directly affects human health by causing hearing loss and indirectly affects human welfare by interfering with sleep, thought, and conversation. In general, portland cement concrete(PCC) pavement is known to create more noise than asphaltic surfaces though it has the advantage of durability and superior surface. However, the results of preliminary laboratory test showed exposed aggregate concrete(EAC) have an effect on reducing traffic noise. Based on the laboratory test, pilot construction of exposed aggregate concrete was performed and series of in-situ measurements were conducted for noise analysis which included the pass-by noise measurement and the close-proximity method. Conclusively, It is expected that tire/pavement noise which is represented much noise levels at higher frequencies would be significantly reduced on special textures of pavement as like exposed aggregate concrete.

• Journal of the military operations research society of Korea
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• v.30 no.2
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• pp.13-31
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• 2004

This paper aims at efficient determining the economic life of weapon systems. Specifically, the procedure to estimate the life cycle cost at initial acquisition state or at development state using the PRICE model is proposed. The PRICE model is a parametric cost estimation which is widely used in the field of national defense. The model includes the estimation of the cost in life cycle of weapon systems such as research and development, acquisition, operation and support. Using this model, economic life of weapon systems can be determined. Based on an equivalent annual cost (EAC) method which sums the capital recovery with return (CR) and the equivalence cost (EC), the economic life will be calculated. A case study is accomplished to illustrate the proposed procedure.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.13 no.2
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• pp.19-30
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• 2017

Austenitic Stainless Steels (ASSs) are widely used as structural materials in the pressurized water reactors (PWRs) because of their superior mechanical properties and corrosion resistance. However, it is well known that ASSs are susceptible to the environmental assisted cracking (EAC) such as environmental assisted fatigue (EAF) during the long term operation. There have been extensive tests and researches to understand the extent and the mechanisms of environmental effects. In this paper, the world-wide EAF test results of ASSs are introduced including those of Korean test programs. The suggested EAF mechanisms of ASSs are also discussed. Finally, the areas of further research to resolve the issue of EAF are suggested.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.10
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• pp.90-97
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• 1996

This paper presents an efficient parallel implementation and its performance evaluations of a SOFM neural netowrk on the multicomputer. We investigate the parallel performance as the size of a neural network N, the number of the patterns L, and the number of the processors p increase. We propose an analytica performance evaluation model for eac of the parallel implementations and verified the validity of the model through experiments. Analytical result show that the number of processors for a maximum speedup of the network decomposition nd the training-set decomposition increases in proportion to .root.N and .root.L, respectively. The performances of the both decompositions depend on the number of training patterns L and the size of the neural network N and, if L.geq.0.423N, the performance of trhe training-set decomposition is proved to be better than that of the network decomposition.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1685-1686
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• 2000

Crack-free and homogeneous com ceramic and epitaxial lead zirconate titanat ferroelectric thin films with perovskite structure been prepared by sol-gel processing. Ti-isoprop and lead acetate trihydrate and zirconium-pro are used raw materials. EAcAc is used as a cat 2-Methoky ethanol is used as a solvent annealing temperatures of the thin films are 0$^{\circ}C$.

• Corrosion Science and Technology
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• v.2 no.2
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• pp.93-97
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• 2003

Fatigue crack growth test or low alloy steel was performed in high temperature water. Test parameters were dissolved oxygen content. loading frequency and R-ratio ($P_{min}/P_{max}$). Since the sulfur content or the steel was low, there were no environmentally assisted cracks (EAC) in low dissolved oxygen(DO) water. At high DO, the crack growth rate at R = 0.5 tests was much increased due to environmental effects and the crack growth rate depended on loading frequency and maximized at a critical frequency. On the other hand, R = 0.7 test results showed an anomalous decrease of the crack growth rate as much different behavior from the R = 0.5. The main reason of the decrease may be related to the crack tip closure effect. All the data could be qualitatively understood by effects of oxide rupture and anion activity at crack tip.

• The Korean Journal of Cytopathology
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• v.19 no.1
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• pp.52-56
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• 2008

Epithelial-myoepithelial carcinoma (EMC) is a low grade malignant neoplasm that commonly occurs in the parotid gland. Recently, we investigated a case of EMC that occurred in the external auditory canal (EAC) in a 35-year-old male, and this tumor was initially diagnosed as pleomorphic adenoma. The difficulty associated with diagnosing EMC by aspiration cytology arises from both the rare incidence of this tumor and the overlapping spectrum of cytological features found in various salivary gland tumors, such as pleomorphic adenoma, basal cell adenoma and adenoid cystic carcinoma.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2018.11a
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• pp.141-142
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• 2018

360 비디오는 VR 미디어의 확산과 함께 몰입형 미디어로 주목 받고 있으며, JVET(Joint Video Experts Team)에서는 post-HEVC 로 진행중인 VVC(Versatile Video Coding) 표준화에 360 비디오 부호화도 함께 포함하고 있다. 현재 JVET 에서는 360 비디오를 부호화 하기 위한 다양한 구(sphere) 영상의 2D 투영기법이 고려되고 있다. 이러한 2D 투영에서는 구 영상의 화소 샘플이 2D 영상에 비 균일하게 매핑되는 변환 왜곡이 발생하며, 이는 360 비디오의 부호화 효율을 저하시키는 원인이 된다. 본 논문에서는 CMP 의 개선된 투영기법인 기존의 EAC(Equi-Angular Cubemap)와 HEC(Hybrid Equiangular Cubemap)를 소개하고, 이를 바탕으로 HEC 의 확장 변환 기법을 제시하여 객관적/주관적 부호화 성능을 확인한다.