• 대한조선학회논문집
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• 제44권6호
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• pp.627-634
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• 2007

A bonded plate or a coated part can be debonded by external impact or thermal expansion. To analyse adhesive strength, the blister test is generally adopted. In this paper, a blister test is modelled theoretically and then the stability and bifurcation of the blister are studied under several different cases. The blister is simplified to consist of a pure bending plate attached elastically to the rigid substrate. Expression of the energy release rate is obtained as a form of an explicit function for a circular-type blister or tunnel-type blister grown by controlling the internal pressure or internal volume. Stability and bifurcation are also studied in the frame of the quasi-static evolution. The study shows that the circular- type blister propagates with the first mode of bifurcation and that the tunnel-type blister propagates with a regular wave. It is proved that the waves have the same form on two side lines of the tunnel and that the wave length can be obtained. When the internal pressure is controlled, the blister is unstable, but when the internal volume is controlled, it is stable.

• 대한전자공학회논문지SD
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• 제41권8호
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• pp.17-24
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• 2004

Density-gradient 방법을 이용하여 게이트의 양자효과가 double-gate MOSFET의 단채널 효과에 미치는 영향을 2차원으로 분석하였다. 게이트와 sidewall 산화막 경계면에서 발생하는 2차원 양자공핍 현상에 의하여 게이트 코너에 큰 전하 다이폴이 형성되며 subthreshold 영역에서 다이폴의 크기가 증가하고 classical 결과에 비하여 전자 농도와 전압 분포가 매우 다름을 알 수 있었다. Evanescent-nude분석을 통하여 게이트의 양자효과가 소자의 단채널 효과를 증가시키며 이는 기판에서의 양자효과에 의한 영향보다 크다는 것을 확인하였다. 양자효과에 의하여 게이트 코너에 형성되는 전하 다이폴이 단채널 효과를 증가시키는 원인임을 밝혔다.

• 전기학회논문지
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• 제61권9호
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• pp.1242-1248
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• 2012

Electric vehicle usage is currently very low, but it will be increase with development of electric vehicle technology and a good government policy. Moreover in 2020, advanced electric vehicle manufacturing system will give high performance for its price and mass production. Electric vehicle will become widespread in Korea. From an operational and a planned viewpoint, the electric power demand should be considered in relation to diffusion of electric vehicles. This paper presents the impact of the various battery charge systems. A comparison is performed for electric vehicle charging methods such as, normal charging, fast charging, and battery swapping. In addition, economic evaluation for the replaceable battery system and the quick battery charging system is performed through basic information about charging Infrastructure installation cost. The results of the evaluation show that replaceable battery system is more economical and reliable in side of electric power demand than quick battery charging system.

• 해양환경안전학회지
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• 제25권3호
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• pp.354-365
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• 2019

Megabenthos samples were collected using 10-min trawls towed at 17 stations from 2015 to 2016. The dominant species (>1% of the total density) were Stegophiura sterea (10.4%) and two subtropical species, Mactrinula dolabrata (9.0%) and Acila divaricate (8.3%), respectively. The community structure of the megabenthos fell into four groups: the southeast, the southernmost region off Jeju Island, the frontal zone of the South Sea with C3, and a diagonal area from the south coast to the western side of Jeju Island. The total numbers of species, diversity, density and biomass were higher in the C3 region of the South Sea. Environmental factor analysis showed that differences in the megabenthos community were related to depth, gravel contents, and sorting value (${\sigma}$). These results indicate that changes in the marine environmental conditions in the South Sea of Korea affect the megabenthos species' composition and diversity.

• 정보보호학회논문지
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• 제18권4호
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• pp.123-133
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• 2008

정보시스템의 확대 및 인터넷 사용의 급격한 증가에 따라 정보보안의 중요성이 대두되고 있다. 그럼에도 불구하고, 우리는 정보보안의 중요성을 심각하지 않게 받아들이고 있다. 본 연구는 조직에서의 보안정책이 정보시스템 사용자의 보안의 식과 개인적 특성에 변화가 있는지 살펴보고, 보안의식과 개인적 특성이 패스워드 사용에 있어서의 보안효과를 가져다주는지 실증분석 하는 것이 궁극적인 목적이다. 구조방정식 모형 기법을 적용한 본 연구모형의 분석결과에 의하면, 보안정책은 개인적 특성과 사용자의 보안의식 향상에 통계적으로 유의한 영향을 미친다. 또한 개인적 특성과 보안의식은 보안효과에 긍정적인 영향을 미치는 것으로 나타났다. 따라서 기업 내의 정보보안은 보안정책을 잘 준수하고 이에 따른 개인적 특성과 보안의식 수준이 향상되었을 때 보다 안전한 패스워드의 보안효과를 거둘 수 있다.

• 한국환경과학회지
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• 제30권3호
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• pp.257-266
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• 2021

This study explored measures to reduce noise applicable to Gimhae international airport centering on densely packed housing areas. Especially, as for measures to relieve noise damage on the densely packed housing areas in Gimhae-si, the noise reduction effect is expected to be doubled if the west runway (36L/18R) is used as the preferred runway for the 36 direction takeoff, as well as if the flight bypasses the densely packed housing areas by means of sophisticated navigation using the area navigation (RNAV) procedure based on performance-based navigation (PBN). Takeoff toward the south connects the flight path to the South Sea which has comparatively low noise impact, relieving noise damage on the densely packed housing areas (apartment complexes in Naeoe-dong of Gimhae-si, etc.) near the northern end of the runway. The operation of the runway displaced threshold is currently being implemented on the west runway (36L/18R) of Gimhae international airport. It has been found that swing landing in spring and summer when the wind blows from the south has a noise reduction effect on the noise sensitive areas at the side and end of the west runway (Gangdong-dong and Jukdong-dong of Gangseo-gu and Buram-dong of Gimhae-si, etc.).

• 한국ITS학회 논문지
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• 제17권2호
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• pp.128-141
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• 2018

본 논문에서는 대표적인 6대 협력형 차량 안전 시스템 대한 잠재적인 사회적 안전효과를 분석하는 방법론을 제시하고자 한다. 협력형 차량 안전시스템의 도입 및 확산을 위해서는 사회적으로 어떠한 파급효과를 가져올지에 대하여 안전 시스템 별 정량적 분석이 필요하다. 국내에서 사고유형 기반으로 분석이 이루어진 사례들이 있으나, 사고 시나리오를 기반으로 한 분석방법론을 찾아보기 어렵다. 이러한 방법론을 제시하기 위해서 우선 승용차나 승합차만을 대상으로 한 국내 사망교통사고 데이터를 기반으로 사고 시나리오를 분류한다. 다음으로 사고 시나리오를 분석하여 협력형 차량 안전 시스템에 적용 가능한 시나리오를 선정하고 결과적으로 사망 사고 빈도수를 통해 안전 시스템의 잠재적인 사회적 안전효과를 정량적으로 제시한다. 마지막으로 안전효과의 정량적 분석을 이용하여 협력형 차량 안전 시스템의 인증을 위한 대표 평가 시나리오를 제시한다.

• Ocean Systems Engineering
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• 제3권1호
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• pp.35-53
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• 2013

In this study, a hybrid floating structure with cylinder was introduced to reduce the hydrodynamic motions of the pontoon type. The hybrid floating structure is composed of cylinders and semi-opened side sections to penetrate the wave impact energy. In order to exactly investigate the hydrodynamic motions and structural behavior of the hybrid floating structure under the wave loadings, integrated analysis of hydrodynamic and structural behavior were carried out on the hybrid floating structure. Firstly, the hydrodynamic analyses were performed on the hybrid and pontoon models. Then, the wave-induced hydrodynamic pressures resulting from hydrodynamic analysis were directly mapped to the structural analysis model. And, finally, the structural analyses were carried out on the hybrid and pontoon models. As a result of this study, it was learned that the hybrid model of this study was showed to have more favorable hydrodynamic motions than the pontoon model. The surge motion was indicated even smaller motion at all over wave periods from 4.0 to 10.0 sec, and the heave and pitch motions indicated smaller motions beyond its wave period of 6.5 sec. However, the hybrid model was shown more unfavorable structural behavior than the pontoon model. High concentrated stress occurred at the bottom slab of the bow and stern part where the cylinder wall was connected to the bottom slab. Also, the hybrid model behaved with the elastic body motion due to weak stiffness of floating body and caused a large stress variation at the pure slab section between the cylinder walls. Hence, in order to overcome these problems, some alternatives which could be easily obtained from the simple modification of structural details were proposed.

• Earthquakes and Structures
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• 제19권4호
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• pp.273-286
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• 2020

The pile group foundation is widely used for gravity pier of high-speed railway bridges in China. If a moderate or strong earthquake occurs, the pile-surrounding soil will exhibit obvious nonlinearity and significant pile group effect. In this study, an improved pushover analysis model for the pile group foundation with consideration of pile group effect is presented and validated by the quasi-static test. The improved model uses simplified springs to simulate the soil lateral resistance, side friction and tip resistance. PM (axial load-bending moment) plastic hinge model is introduced to simulate the impact of the axial force changing of pile group on their elastic-plastic characteristics. The pile group effect is considered in stress-stain relations of the lateral soil resistance with a reduction factor. The influence factors on nonlinear characteristics and plastic hinge distribution of the pile group foundation are discussed, including the pier height, longitudinal reinforcement ratio and stirrup ratio of the pile, and soil mechanical parameters. Furthermore, the displacement ductility factor, resistance increase factor and yielding stiffness ratio are provided to evaluate the seismic performance of soil-pile system. A case study for the pile group foundation of a railway simply supported beam bridge with a 32 m-span is conducted by numerical analysis. It is shown that the ultimate lateral force of pile group is not determined by the yielding force of the single one in these piles. Therefore, the pile group effect is essential for the seismic performance evaluation of the railway bridge with pile group foundation.

• 한국환경교육학회지:환경교육
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• 제18권1호
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• pp.55-69
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• 2005

This study aims to investigate and practically examine the effect of environmental qualifications based on the theoretical background on the area. First, the economic effect of the acquisition of the qualifications was to be studied from the viewpoints of individuals and from an actual analysis on it, its effect was to be proved. Second, its non-economic effect was to be proved from the same way as the first analysis. On the basis of theoretical background, a study model was formulated in a way that the effect of qualifications in individuals side was divided into an economic effect (wage, employment, promotion, job-switching) and non-economic effect (self-development, self-efficiency, satisfaction on the job, ability to cope with the advancement of technology, job performance, signal effect, the settlement of uneasiness at unemployment). Then, survey was carried out with questions designed in accordance with this model. The hypotheses were proved as the following. First, for hypothesis 1(Environmental qualifications will bring up positive impacts on an individuals economic effect), environmental qualifications was shown to have positive impacts on wage, job-switching in personal economic effect. But, no personal economic effect appeared for employment and promotion. Second, for hypothesis 2(Environmental qualifications will bring up positive impacts on an individuals non-economic effect), environmental qualifications appeared to have positive impacts on self-efficiency, ability to cope with the advancement of technology, job performance and signal effect. Besides, no impact was shown in satisfaction on the job and the settlement of uneasiness at unemployment and self-development.