• 한국지진공학회논문집
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• 제23권4호
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• pp.201-209
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• 2019

Response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills in 'Manual for Seismic Performance Evaluation and Retrofit of School Facilities' published in 2018 were investigated in the preceding study. However, since previous studies are based on 2D frame analysis and limited analysis conditions, additional verification needs to be performed to further apply various conditions including orthogonal effect of seismic load. Therefore, this study is to select appropriate response modification factors of school facilities for non-seismic RC moment frames with partial masonry infills by 3D frame analysis. The results are as follows. An appropriate response modification factor for non-seismic RC moment frames with partial masonry infills is proposed as 2.5 for all cases if the period is longer than 0.6 seconds. Also if the period is less than 0.4 seconds and the ratio of shear-controlled columns is less than 30%, 2.5 is chosen too. However, if the period is less than 0.4 seconds and the ratio of shear-controlled columns is higher than 30%, the response modification factor shall be reduced to 2.0. If the period is between 0.4 and 0.6 seconds, then linearly interpolates the response correction factor.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.713-723
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• 2017

As a new type of ballastless track, longitudinal continuous slab track (CST) has been widely used in China. It can partly isolate the interaction between the ballastless track and the bridge and thus the rail expansion device would be unnecessary. Compared with the traditional track, CST is composed of multi layers of continuous structures and various connecting components. In order to investigate the performance of CST on a long-span bridge, the spatial finite element model considering each layer of the CST structure, connecting components, bridge, and subgrade is established and verified according to the theory of beam-rail interaction. The nonlinear resistance of materials between multilayer track structures is measured by experiments, while the temperature gradients of the bridge and CST are based on the long-term measured data. This study compares the force distribution rules of ballasted track and CST as respectively applied to a long span bridge. The effects of different damage conditions on CST structures are also discussed. The results show that the additional rail stress is small and the CST structure has a high safety factor under the measured temperature load. The rail expansion device can be cancelled when CST is adopted on the long span bridge. Beam end rotation caused by temperature gradient and vertical load will have a significant effect on the rail stress of CST. The additional flexure stress should be considered with the additional expansion stress simultaneously when the rail stress of CST requires to be checked. Both the maximum sliding friction coefficient of sliding layer and cracking condition of concrete plate should be considered to decide the arrangement of connecting components and the ultimate expansion span of the bridge when adopting CST.

• 한국통신학회논문지
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• 제36권12B호
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• pp.1481-1488
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• 2011

최근 공격기술은 네트워크의 진화와 함께 다양한 형태로 나타나고 있으며, 대부분의 네트워크에서는 다양한 보안장치들을 통해 대응하고 있다. 또한 외부 공격으로부터 내부 네트워크의 정보자산을 보호하기 위해 기존 네트워크에 필요한 보안시스템들을 추가 배치하고 있다. 그러나 이와 같은 보안시스템의 사용은 내부 네트워크의 성능과 보안에 큰 영향을 미칠 뿐만 아니라 이로 인해 경제적인 추가비용을 발생시킨다. 따라서 본 논문은 내부 네트워크의 보안으로 인한 추가 비용의 요인들에 대해 예상하기 어려운 가변적 상황과 정보보호 인식수준, 보안시스템, 정보자산 평가유무 등을 관련 연구자료 및 실험결과를 분석함으로써, 향후 관련 정책수렵과 내부 네트워크의 구축 및 설계에 따른 비용절감의 기초자료로 활용될 것으로 기대한다.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.21-30
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• 2023

This work presents a correlation between the behavior of formic acid oxidation (FAO) on various Bi-modified Pt(poly) disk electrodes and their morphologies observed on Bi-modified Pt(111) disk electrodes using electrochemical scanning tunneling microscopy (EC-STM) to understand the effects of Bi on Pt. To distinguish the FAO activities of Bi on Pt and plain Pt around Bi, additional Pt was intentionally deposited using two different routes: direct route and iodine route. In direct route, Pt was directly deposited on Bi islands and plain Pt sites around Bi islands, while in iodine route, Pt was exclusively deposited on Bi islands by protecting plain Pt sites with adsorbed iodine. Thus, a comparison of FAO performances on the two Bi-modified Pt electrodes with additional Pt (deposited in the different ways) disclosed a difference in FAO performances on plain Pt sites and Bi islands. When Bi coverage was ~0.04, the Bi deposits were scattered Bi islands enhancing FAO on Pt(poly). The additional Pt deposits using direct route increased FAO efficiency, while the ones using iodine route slightly decreased FAO current. The EC-STM observations indicated that Pt deposits around Bi islands, not on Bi islands, were responsible for the FAO current increase on Bi-modified Pt(poly). The FAO efficiency on Bi-modified Pt(poly) with a Bi coverage of ~0.25 increased by a factor of 2. However, the additional Pt deposits using the two Pt deposition routes notably decreased the FAO current. The dependency of FAO on Bi coverage was discussed in terms of electronic effect and ensemble effect.

• 한국조경학회지
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• 제35권1호
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• pp.79-87
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• 2007

The objective of this study was to delineate forest patches in the cities around the Geum-buk mountains at the north of the Geum River using multiplesatellite remote sensing data. Landsat visible and near-infrared satellite images obtained at multiple dates in the growing season were used to create a forest distribution map. Fragstats 3.3 was used to get the landscape indices delineating the distribution of forest patches. Additional ground truth data was used to assess the accuracy of the classification. Factor analysis was used to get the 26 landscape indices clustered into 4 factors. Factor I was labeled as' size of forest patches', factor II as 'fragmentation of forest patches', factor III as 'shape of forest patches', and factor IV as 'complexity of forest patches'. Factor I described large patches and their core area, while others did small patches and their shape and complexity. Cities including Cheonan, Gongju, Cheongyang, and Boryeong near the main ridge of the Geumbuk Mtns. had a small number of large-sized forest patches. However, cities including Taean, Seosan, Dangjin, Hongseong near the ridge of the western Geumbuk Mtns. had a large number of small-sized forest patches. Finally, this study showed that the region near the coast line in Chung-nam province has various types of forest patches having an irregular forest edge due to the elevation and slope lower than the one of the region far from the coast line which is near the ridge of the Geum-buk Mountains. Remote sensing data were useful to understand the distribution of forest patches, and landscape indices could be keys to delineate the relationship between forest patches. And the factor analysis, which simplified 26 landscape indices into 4 landscape patterns allowed us to understand the distribution and relationship of forest patches in an easy way.

• 한국콘텐츠학회논문지
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• 제17권5호
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• pp.326-336
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• 2017

본 연구는 일부 대학생의 스트레스, 자아요인 및 정서요인과 스마트폰중독정도 간의 관련성을 파악하고 스마트폰중독정도에 미치는 영향을 분석하였다. 조사대상은 J시 2개 대학에서 선정된 261명으로 하였으며, 자료수집은 2016년 12월 16일부터 12월 23일까지 자기기입식 설문지를 통해 이루어졌다. 다중회귀분석 결과, 스마트폰중독정도에 52%의 설명력으로 영향을 미치는 요인은 신체활동변화, 수면장애, 자아요인의 자기통제력, 정서요인의 충동으로 나타났다. 공분산 구조분석 결과, 스트레스, 자아요인 및 정서요인과 스마트폰중독정도의 인과관계가 확인되었다. 연구결과를 볼 때, 대학생의 스마트폰중독정도를 줄이기 위해서는 스트레스, 자아요인 및 정서요인을 관리하는 노력이 필요하다. 이러한 결과는 스마트폰중독정도를 낮추는 프로그램 및 정책 개발에 활용이 기대된다. 향후 연구에서는 스마트폰중독에 영향을 미치는 추가요인에 대한 구조모형 조사가 필요하다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1991년도 추계학술발표회 논문집 지반공학에서의 컴퓨터 활용 COMPUTER UTILIZATION IN GEOTECHNICAL ENGINEERING
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• pp.179-194
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• 1991

This paper explains outline of a behavior analysis program for underground structures, and its application to a tunnel problem. The program can deal with elasto-plastic behavior of medium and supporting structures, discontinuous behavior due to existing joint, creation and propagation of cracks. in-situ loading condition, and incremental behavior due to stepwise excavation, etc. The program also has additional capabilities such as graphic output of mesh, displacement pattern, stress condition, and safety factor contour, and automatic mesh generation during the excavation steps.

• 전기학회논문지
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• 제60권8호
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• pp.1523-1528
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• 2011

This paper proposes buck-type charging method using motor inductance, 3-phase inverter and bi-directional converter without an additional charger in plug-in hybrid electric vehicles. The proposed system has advantages over the conventional system such as high charging efficiency, high power factor, and low total harmonic distortion. The validity of each methods are verified by theoretical analysis and simulation.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.788-793
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• 1995

For a linkage mechanism deiven by cam, cam profile is the major design factor and is determined by the motion type od cam follower. If a cam mechanism has additional kinematic linkages besides cam and follower then the follower motion should be specified form the motion of end linkage member so that cam would be able to generate the desired end linkage motion. In this paper, a cam-linkage mechanism is constructed with the combinations of modular linkage elements including cam and follower and as a resullt, a planar cam-linkage mechanism design software with the cam profile optimization function is developed and presented.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.671-674
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• 1999

In the PWM converter, PLL(Phase Locked Loop) is usually used as a tool which senses the angle of input voltage. This is sensitive to nois and needs additional hardware. In this work, we propose a sensorless control scheme of PWM converter using EKF(Extended Kalman Filter). EKF estimates a phase angle of input voltage from nonlinear state equation using measured phase currents. We control power factor and DC-link voltage utilizing the estimated phase angle. We demonstrate the effectiveness of the proposed estimation algorithm through simulations.