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지지점 가속도에 의해 가진되는 보의 응력계산에 대한 거대질량법의 정확도 (Numerical Tests of Large Mass Method for Stress Calculation of Euler-Bernoulli Beams Subjected to Support Accelerations)

  • 김용우;최남석;정명조
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2013년도 춘계학술대회 논문집
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    • pp.188-193
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    • 2013
  • The large mass method for dynamic analysis of statically determinate beams subjected to in-phase support motions is justified by showing that the equation of motion of the beams under consideration is equivalent to that of large mass model of the beam when an appropriate large mass ratio is employed. The accuracy of the stress responses based on the beam large mass method is investigated through careful numerical tests. The numerical results are compared to analytic solutions and the comparison shows that the large mass method yields not only the time history of motion but also the distributions of bending moment and shear force accurately.

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Real-time Object Recognition with Pose Initialization for Large-scale Standalone Mobile Augmented Reality

  • Lee, Suwon
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제14권10호
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    • pp.4098-4116
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    • 2020
  • Mobile devices such as smartphones are very attractive targets for augmented reality (AR) services, but their limited resources make it difficult to increase the number of objects to be recognized. When the recognition process is scaled to a large number of objects, it typically requires significant computation time and memory. Therefore, most large-scale mobile AR systems rely on a server to outsource recognition process to a high-performance PC, but this limits the scenarios available in the AR services. As a part of realizing large-scale standalone mobile AR, this paper presents a solution to the problem of accuracy, memory, and speed for large-scale object recognition. To this end, we design our own basic feature and realize spatial locality, selective feature extraction, rough pose estimation, and selective feature matching. Experiments are performed to verify the appropriateness of the proposed method for realizing large-scale standalone mobile AR in terms of efficiency and accuracy.

한반도 기온 및 강수량 변동에 영향을 미치는 광역규모 기후지수들에 대한 고찰 (An Investigation of Large-Scale Climate Indices with the influence on Temperature and Precipitation Variation in Korea)

  • 김연희;김맹기;이우섭
    • 대기
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    • 제18권2호
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    • pp.83-95
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    • 2008
  • In this study we have investigated the preceding eighteen large-scale climate indices with a lead time from zero to twelve months that have an influence on the variability of temperature and precipitation in Korea in order to understand which climate indices are overall available as predictors for long-range forecasting. We also have studied the dynamic link between preceding large-scale climate indices and regional climate using singular value decomposition analysis (SVDA) and correlation analysis (CA). Based on the coupled mode between large-scale circulation and regional climate, and correlation pattern between the preceding large-scale climate indices and large-scale circulation, the level of significance on climate indices as a predictor for monthly mean temperature and precipitation was evaluated for 5 and 1% level.

대공간 건축물 지붕공사의 시공기법선정을 위한 기초연구 (A preliminary Study on Selection of Construction Method for Roofing work in Large-Scale Structures)

  • 김대길;홍주영;이명도;엄진업;김대원
    • 한국건축시공학회:학술대회논문집
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    • 한국건축시공학회 2016년도 춘계 학술논문 발표대회
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    • pp.247-248
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    • 2016
  • Globally the interest of large-scale structure has been increasing for the use in various social and cultural events. However various problems for building large-scale structure in South Korea are expected in terms of construction method and site management due to the lack of experience. Construction method and planning significantly affects on making decisions. There are only theoretical approach for constructing large-scale building in domestic with the limited experience of constructing constrained size structure. Through Analytic Hierarchy Process with experts, derived decision factors mostly used construction method in construction of large-scale structure. Derived factors from this study will support making decisions for field management in constructing large-scale structure.

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Simulation of large wind pressures by gusts on a bluff structure

  • Jeong, Seung-Hwan
    • Wind and Structures
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    • 제7권5호
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    • pp.333-344
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    • 2004
  • This paper illustrates application of the proper orthogonal decomposition (POD) and the autoregressive (AR) model to simulate large wind pressures due to gusts on a low-rise building. In the POD analysis, the covariance of the ensemble of large wind pressures is employed to calculate the principal modes and coordinates. The POD principal coordinates are modeled using the AR process, and the fitted AR models are employed to generate the principal coordinates. The generated principal coordinates are then used to simulate large wind pressures. The results show that the structure characterizing large wind pressures is well represented by the dominant eigenmodes (up to the first fifteen eigenmodes). Also, wind pressures with large peak values are simulated very well using the dominant eigenmodes along with the principal coordinates generated by the AR models.

KICT-type 대구경 샘플러의 해상 적용성 검토 (Application of KICT-type Large Diameter Sampler for Offshore Ground Sampling)

  • 김영석;김영진;윤여원;정지원
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.1365-1369
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    • 2008
  • A large diameter sampler (KICT-type large diameter sampler) was developed to take undisturbed samples from not only soft ground but also sandy and weathered ground. The KICT-type large diameter sampler was manufactured with the principle of triple core barrel sampling. In this study, the applicability to offshore ground sampling of the KICT-type large diameter sampler was confirmed at Inchoen Port construction site. And, in order to compare the quality of samples taken by the sampler with that of the traditional piston sampler, a series of laboratory tests were performed. From the test results, the samples taken by the KICT-type large diameter sampler showed higher quality than the traditional thin-walled tube samples.

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입자법을 이용한 지반공학 대변형 문제 해석 (Analyses of Large Deformation Problems in Geotechnical Engineering using Particle Method)

  • 박성식
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2009년도 세계 도시지반공학 심포지엄
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    • pp.1090-1094
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    • 2009
  • Many problems in geotechnical engineering such as slop failure, debris flow, ground heaving due to embankment, and lateral flow caused by liquefaction are related to large deformation rather than small deformation. Traditional numerical methods such as finite element and finite difference methods have a difficulty to solve such large deformations because they use grids. A particle method was developed for fluid dynamics. The particle method can solve large deformation problems because it uses particles to discretize differential equations. It can also include soil constitutive model and thus solve soil behavior on various boundary conditions. In this study, a particle method, which is based on particles rather than grids, is introduced and used to simulate large deformation including soil failure. The developed method can be applied for various large deformation problems in geotechnical engineering because it incorporates soil constitutive models.

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고분자젤 내에서 분자체 거동현상 연구 (Study of Transport Phenomena of Large Ionic - Molecules Inside Polymeric Gel)

  • 박영규;성기천
    • 한국응용과학기술학회지
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    • 제18권1호
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    • pp.1-6
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    • 2001
  • Theoretical model has been studied for the transport phenomena of molecules in the system where an electric potential is applied to the system in the axial direction. The effect of electrophoretic convection in the polymeric media is significantly contributed to separate large ionic-molecules because the conformation of large ionic-molecule quickly orients in the field direction. The dependence of the transport in the polymeric media upon field intensity and molecular size aids in understanding the transport of large ionic-molecule in the system, since the convective velocity of large ionic-molecule is accelerated inside a porous material. The transport distance of individual large ionic-molecule can be predicted using the reptation theories.

LES를 이용한 발전하는 혼합층에서의 입자 운동에 관한 수치 해석 연구 (Numerical study of Particle Motion in a Developing Mixing Layer using Large-eddy Simulation)

  • 김태진;서태원
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집E
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    • pp.94-99
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    • 2001
  • The numerical simulation of the particle dispersion in the vortical flows provides insight into the mechanism of particle-fluid interaction. The simulation results show that the mixing layers are characterized by the large-scale vortical structures undergoing pairing process. The particle dispersion is strongly influenced by the large-scale structures and the particle sizes. The analysis shows that the mixing layers grows like a step-function.

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