• Journal of the Korean earth science society
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• v.34 no.3
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• pp.189-194
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• 2013

In this study, the patterns of barotropic vortices and their structural rotation were investigated through laboratory experiments. Both stable and unstable barotropic vortices were formed in a rotating water tank with a rotating circular plate depending on the diameter, direction, and speed of rotating circular plate. The patterns of stable vortices turned out to be tripolar, triangular, rectangular, and monopolar vortex. These vortex patterns were affected by the gap between the circular plate and the wall of the water tank. Many unstable vortices were formed by anticyclonically and highly rotating circular plate. These results were caused by the centrifugal instability. The structural angular velocity of the tripolar vortex increased with the tangential velocity of the circular plate. The anticyclonic tripolar vortex had higher structural angular velocity than the cyclonic vortex. The tripolar vortex in the water tank was very similar with the real oceanic tripolar vortex from the view point of the Rossby number and the structural rotation.

• Electronics and Telecommunications Trends
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• v.24 no.2
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• pp.131-141
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• 2009

통신서비스 시장은 유무선 및 통신과 방송서비스의 컨버전스화가 진행됨에 따라 미래 시장에서의 경쟁구도에 관심이 집중되고 있다 최근 영국, 이탈리아 등 유립을 중심으로 지배적 사업자의 병목설비에 대한조직분리의 일환으로 기능분리가 활발하게 논의 및 도입되고 있다. 이 중 이탈리아는 TI에 대한 운영분리 수준의 구조규제를 기능분리 수준으로 강화하였다. 이는 운영분리와 같은 구조적인 조치에도 불구하고 TI의 지배력 유지, 경쟁 사업자들의 지속적 불만 제기 등의 문제가 해결되지 않은데다가 TI의 소유구조 변화에 따른 네트워크의 안정성 및 보안성에 대한 우려에 따른 것으로 해석되고 있다. 이탈리아의 기능분리는 동등접속을 위한 사업부로 Open Access의 설립, 신규 인센티브 제도, 각종 투명성 확보장치, 감독기관의 신설 등의 내용이 포함되어 있으며 근본적인 원칙은 영국의 경우와 유사하다. TI는 기능분리를 통해 규제기관과의 관계 개선, 소매시장 규제완화 등의 효과를 기대하고 있으며 2008년 2월 Open Access를 출범하였다.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2017.05a
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• pp.146-146
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• 2017

산화비스무트는 리튬이온과의 반응에서 현재 상용화된 그래파이트보다 높은 이론용량을 가지고 있으나, 리튬이온과의 반응에서 비교적 큰 부피팽창 특성을 가져 리튬이차전지의 음극재로서 상용화가 어려운 단점이 있다. 본 연구에서는, 이러한 문제점을 개선하기 위하여 양극산화법을 통해 충 방전시 부피팽창 변화가 매우 적은 타이타니아 나노튜브를 제조한 후, 그 위에 스프레이 방법으로 산화비스무트를 코팅하여 두 물질의 복함체를 만듦으로써 용량과 구조적 안정성을 향상시키는 방법을 소개한다. 음극재의 구조적 특성은 고분해능 주사전자현미경 (HR-SEM), 고분해능 엑스선 회절분석기(XRD)를 통해 조사하였으며, 전기화학 임피던스 분광법 (EIS), 순환전류법 (CV), 충 방전 싸이클 분석을 통해 리튬이차전지의 작동원리와 보다 향상된 성능을 규명하였다.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1931-1935
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• 2010

최근 기후변화에 의한 강우량 및 집중호우의 증가로 인하여 설계규모를 초과하는 홍수발생 가능성이 커지고, 이에 따라 제방월류 위험성이 증대되고 있다. 특히, 하천을 횡단하는 보 또는 낙차공이 있는 경우, 구조물 영향에 의해 국부적으로 유속이 증가하여 연결호안을 유실시킴으로서 제방붕괴에 의해 홍수피해가 가중될 수 있다. 과거 피해사례를 보면 횡단구조물과 제방과의 연결부가 세굴되어 파괴되는 사례가 많이 발생하고 있으며, 이는 하천횡단구조물 주위에 설치되는 연결호안에 대한 정량적인 설계기법이 정립되어야 할 필요성을 보여 준다. 경험적인 요소만으로 연결호안의 안정성을 판단함으로써, 과소설계에 의한 홍수피해가 발생하거나, 과대설계에 의한 비용손실을 초래하게 된다. 본 연구에서는 기존에 제시되어 있는 호안설계식을 연결부에서의 국부유속증가특성을 고려하여 적용한 결과를 비교하였다. 비교 결과, 연결부에서의 호안 크기가 증가될 필요가 있으며, 이에 대한 실험 실증적 연구가 필요한 것으로 분석되었다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.1
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• pp.37-49
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• 2012

A structural model of the SNF(spent nuclear fuel) disposal canister for the PWR(pressurized water reactor) for about 10,000 years long term deposition at a 500m deep granitic bedrock repository has been developed through various structural safety evaluations. The SNF disposal baskets of this canister model have the array type whose four square cross section baskets stand parallel to each other and symmetrically with respect to the center of the canister section. However, whether this developed structural model of the SNF disposal canister is optimal is not determinable yet. Especially, there is still a problem in weight-reduction of the canister. The cross section shape of the SNF basket should be changed to solve this problem. There are two ways in changing the cross section shape of the SNF basket; the one is to rotate the cross section itself and the other is to change the cross section shape as other shape different from the square cross section. The previous study shows that the canister with $30{\sim}35^{\circ}$ rotated basket array is structurally more stable than the canister with un-rotated parallel basket array. However, whether this canister with rotated basket array is optimal is not either determinable as yet, because it is not revealed that the canister with other cross section different from the square cross section is structurally more stable than other canisters. Therefore, the structural analysis of the SNF disposal canister with other cross section shape which is also symmetric with respect to the canister center planes is very necessary. The structural analysis of the canister with various cross section shape basket array in which each basket is arrayed symmetrically with respect to the center planes is carried out in this paper. The structural analysis result shows that the SNF disposal canister with circular cross section shape baskets located symmetrically with respect to the center of the canister section is structurally more stable than the previously developed SNF disposal canister with the parallel basket array.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.3
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• pp.8-15
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• 2018

An experiment was carried out to evaluate the lateral torsional stability of a girder with respect to the location and magnitude of prestressing force. The test of evaluating the lateral displacement and stability of a girder could cause an unexpected result due to various parameters, such as material nonlinearity, initial geometric imperfections, prestressing force, and loading and support conditions. Therefore, a small model testing was programmed to control the various parameters and assess the lateral torsional stability with respect to the prestressing force. This study proposed and fabricated an experimental apparatus that can satisfy the loading and in-plane and out-of-plane support conditions and also contol the prestressing force. The result of the experiment showed that the lateral torsional stability increased when the prestressing force was applied in the bottom flange of the girder. As a result, this study proposed an analytical equation that can account for the effect of the prestressing force in the lateral torsional stability of a girder.

• Journal of the Korean Geotechnical Society
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• v.21 no.2
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• pp.57-65
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• 2005

Geotextile have been used for the past 30 years for various types of containers, such as small sandbag, 3-D fabric forms and aggregate filled gabion etc. While they are mainly used for flood and water control, they are also used against beach erosion fir shore protection. Especially, large-sized geotextile tube structures are used in various innovative coastal systems involving breakwaters. This paper presents the hydrodynamic behavior of geotextile tubes based on the results of hydraulic model tests. These tube are generally about 1.0 m to 2.0 m in diameter, thou띤 they can be sized for any application. The tubes can be used solely, or stacked to add greater height and usability. Stacked geotextile tubes will be created by adding the height necessary for some breakwaters and embankment, therefore increasing the usability of geotextile tubes. The hydraulic model test was conducted as structural condition and wave conditions. Structural condition is installation direction to the wave (perpendicular and 45$^{circ}$$), and wave condition is varied with the significant wave height ranging from 3.0 m to 6.0 m. Compared with previous test result, the stacked geotextile tube is more stable against wave attack than single tube. Also, the case of none-water depth above crest is more stable than 0.5H of water depth above crest. The incline installed stacked tube is more effective for wave adsorption.

• Journal of Global Scholars of Marketing Science
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• v.7
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• pp.321-337
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• 2001

The Purpose of this study is to empirically examine the factors that affect the consumer's buying behavior under the e-commerce environment. In order to achieve this goal, vendor characteristics, securities of transaction, concern for privacy, shopping orientation and perceived channel utilities were used as independent variables. Findings of study indicated that the concerns for abusing individual information, perceived securities of transaction, consumer's recreational orientation, consumer's convenience orientation, perceived distribution channel are the robust predictors of buying behavior of internet users.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.3
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• pp.207-216
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• 2002

Conventional Korean tunnel portals require a lot of overburden. For stability reasons, about 1.5 to 2.0 times the tunnel diameter is needed for the height in order to achieve a sufficient arching effect. Thus, considerable movement of earth and support constructions are required which lead to undesirably large changes of and damage to the environment. With a massively designed pipe roof, tunnels at low overburden can be built. To effectively construct pipe roof as an advanced safeguarding method, the following properties are indispensable: stability, insensitivity to settling and drilling accuracy. A new pipe roof method, AT-casing system, has been developed which on the one hand entirely combines the properties mentioned above, and which on the other hand permits the construction of safe, economical and environmentally friendly tunnels at low overburden heights of 3 to 5m.

• Annual Conference of KIPS
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• 2009.11a
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• pp.363-364
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• 2009

방송 산업이 기술적 구조적으로 발전하고 시청자의 수준 향상 및 문화 산업이 급변함에 따라 현대사회에서 방송 분야는 거대 성장을 거듭하고 있다. 이러한 방송 산업의 시대적 변화속에서 지속적으로 관심의 대상이 되고 있는 것이 시청자들의 수준 및 변화의 초점이며 이를 파악하여 원활한 방송의 진행을 주도해야 하는 것이 방송 진행자의 역할이다. 따라서 본 논문에서는 충북지역의 방송 3사에서 뉴스를 담당하고 있는 진행자에 대한 음성을 수집하여 다양한 음성 분석 요소들을 적용하고 이에 따른 결과값을 기반으로 방송 진행자의 음성에 대한 특징적 정보를 추출하는 실험을 수행하였다. 특히, 음성을 통해 전달할 수 있는 영향력을 분석하기 위해 피치, 지터, 짐머, 안정도, 및 스펙트로그램 등의 다양한 음성 분석 요소를 적용하였으며 결과값에 대한 비교, 분석을 수행하였다.