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검색결과 410건 처리시간 0.023초

Numerical study on Floor Response Spectrum of a Novel High-rise Timber-concrete Structure

  • Xiong, Haibei;Zheng, Yingda;Chen, Jiawei
    • 국제초고층학회논문집
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    • 제9권3호
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    • pp.273-282
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    • 2020
  • An innovative high-rise timber-concrete hybrid structure was proposed in previous research, which is composed of the concrete frame-tube structure and the prefabricated timber modules as main structure and substructures, respectively. Considering that the timber substructures are built on the concrete floors at a different height, the floor response spectrum is more effective in estimating the seismic response of substructures. In this paper, the floor response spectra of the hybrid structure with different structural parameters were calculated using dynamic time-history analysis. Firstly, one simplified model that can well predict the seismic response of the hybrid structure was proposed and validated. Then the construction site, the mass ratio and the frequency ratio of the main-sub structure, and the damping ratio of the substructures were discussed. The results demonstrate that the peaks of the floor response spectra usually occur near the vibration periods of the whole structure, among which the first two peaks stand out; In most cases, the acceleration amplification effect on substructures tends to be more evident when the construction site is farther from the fault rupture; On the other hand, the acceleration response of substructures can be effectively reduced with an appropriate increase in the mass ratio of the main-sub structure and the damping ratio of the substructures; However, the frequency ratio of the main-sub structure has no discernible effect on the floor response spectra. This study investigates the characteristics of the floor response spectrum of the novel timber-concrete structure, which supports the future applications of such hybrid structure in high-rise buildings.

WRAN 응용을 위한 하향링크 무선전송 방식 : OFDMA 상황인식 시스템에서의 적응 부채널 할당 및 고정 빔 형성 기법 (DL Radio Transmission Technologies for WRAN Applications : Adaptive Sub-channel Allocation and Stationary Beamforming Algorithms for OFDMA CR System)

  • 김정주;고상준;장경희
    • 한국통신학회논문지
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    • 제31권3A호
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    • pp.291-303
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    • 2006
  • 본 논문에서는 현재 진행 중인 IEEE 802.22 WRAN의 Functional Requirements를 분석하고, 제시된 Requirements를 만족시키는 하향링크 프레임 구조를 제안한다. 제안된 하향링크 프레임 구조는 WRAN 각 채널 환경하에서의 상황인식 적응 Traffic Channel에 의한 Rate Control을 수행하여 전송 효율을 극대화시키며, 이를 위한 하항링크와 상향링크의 Signaling Overhead를 계산한다. 그리고, 하링링크의 프리앰블을 이용한 시간, 주파수동기 및 셀 ID 탐색 성능을 분석하고, 프리앰블 또는 Pilot에 의한 환경 적응적 채널 추정 방법과 동적채널할당(Dynamic Channel Allocation)을 결합한 고정 빔형성(Stationary Beamforming) 알고리즘을 제안한다. 또한, 모의실험을 통하여 이와 같이 제안된 무선 채널 환경에서 적응 부채널 할당 기능을 고려한 상황인식 하향링크 프레임구조가 IEEE 802.22 WRAN 시스템의 요구사항을 만족시킴을 검증한다.

객체 추적을 위한 SURF 기반 특이점 추출 및 서술자 생성의 하드웨어 설계 (Hardware Design of SURF-based Feature extraction and description for Object Tracking)

  • 도용식;정용진
    • 전자공학회논문지
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    • 제50권5호
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    • pp.83-93
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    • 2013
  • 최근 영상처리 응용의 일환으로 객체 추적 시스템에 많이 활용되는 SURF 알고리즘의 경우 영상의 회전 및 크기 변화에 강인한 특이점을 추출한다는 특징이 있지만 연산이 복잡하고 연산량이 많아 임베디드 환경에서 IP로 사용되기 위해서는 하드웨어 가속기 개발이 필수적이다. 하지만 이 때 요구되는 내부 메모리 사이즈가 매우 크기 때문에 ASIC이나 SoC 시스템으로 개발 할 때 칩 회로 사이즈가 커서 IP의 가치를 떨어뜨리게 된다. 본 논문에서는 하드웨어 가속기 개발 시 회로면적에 효율적인 설계를 위해 내부 블록메모리 사용량을 줄이고 외부 메모리와 DMA를 사용하여 세분화된 Sub-IP 구조로 설계하는 것에 대해 연구하고 간단한 객체 추적 알고리즘을 개발하여 그 결과를 적용하였다. ARM Cortex-M0, AHB-lite, APB, DMA, SDRAM Controller로 구성된 시스템 환경에서 실험 결과 VGA(640x480)영상에서 SURF 알고리즘의 처리속도는 약 31frame/sec, 블록 메모리의 크기는 81Kbytes, 30nm 공정에서 회로의 크기는 약 74만 게이트 크기로 SoC 칩의 하드웨어 IP로 활용이 가능하였다. SURF와 비슷한 영상처리 알고리즘에서도 본 논문에서 제안하는 설계방법을 적용하면 타겟 어플리케이션에 효율적인 하드웨어 설계를 할 수 있을 것으로 기대된다.

Visual Semantic Based 3D Video Retrieval System Using HDFS

  • Ranjith Kumar, C.;Suguna, S.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • 제10권8호
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    • pp.3806-3825
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    • 2016
  • This paper brings out a neoteric frame of reference for visual semantic based 3d video search and retrieval applications. Newfangled 3D retrieval application spotlight on shape analysis like object matching, classification and retrieval not only sticking up entirely with video retrieval. In this ambit, we delve into 3D-CBVR (Content Based Video Retrieval) concept for the first time. For this purpose we intent to hitch on BOVW and Mapreduce in 3D framework. Here, we tried to coalesce shape, color and texture for feature extraction. For this purpose, we have used combination of geometric & topological features for shape and 3D co-occurrence matrix for color and texture. After thriving extraction of local descriptors, TB-PCT (Threshold Based- Predictive Clustering Tree) algorithm is used to generate visual codebook. Further, matching is performed using soft weighting scheme with L2 distance function. As a final step, retrieved results are ranked according to the Index value and produce results .In order to handle prodigious amount of data and Efficacious retrieval, we have incorporated HDFS in our Intellection. Using 3D video dataset, we fiture the performance of our proposed system which can pan out that the proposed work gives meticulous result and also reduce the time intricacy.

국제적인 의학교육 역량체계 비교를 통한 한의학교육에의 시사점 연구 (A Study on Implications for Korean Medicine Education by Comparing International Competence Frameworks in Medical Education)

  • 신상우;박종배
    • 동의생리병리학회지
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    • 제31권1호
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    • pp.36-45
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    • 2017
  • In order to gain implications for establishing competency-based education system in Korean medicine education, we examined several competence frameworks of medical education developed at international or national level, and compared the basic constitution and common elements. The competence frameworks of medical education consist of seven categories of communication, professionalism, critical thinking, medical knowledge, patient care, management, and public health. Medical knowledge consists of five sub-groups: normal structure and function; pathogenesis and mechanism of disease; principles of drug and treatment; psychological, behavioral and sociological principles; and public health and lifelong learning. In principle, competencies are further divided into sub-categories or combined with learning outcomes, and the field and the level of achievement is presented per item. This article aims at summarizing the competencies of a few globally leading medical institutions with the educational standard of Korean Medicine in mind.

반응면 근사를 이용한 자기부상열차 차체 프레임 경량화 설계 (Light-Weight Design of Maglev Car-Body Frame Using Response Surface Approximation)

  • 방제성;한정우;이종민
    • 한국정밀공학회지
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    • 제28권11호
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    • pp.1297-1308
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    • 2011
  • The light-weight design of UTM (Urban Transit Maglev)-02 car-body frames are performed, based on initial configuration. The thicknesses of fourteen sub-structures are defined as design variables and the loading condition is considered according to weight of sub-structures, electronic and pneumatic modules and passengers. For efficient and robust process of design optimization, objective function and constraints are approximated by response surface approximation. Structural analysis is performed at some sampling points to construct the approximated objective function and constraints composed of design variables. Design space is changed to find many optimal candidates and best optimal design can be found eventually. The Matlab Optimization Toolbox is used to find optimal value and sensitivity analysis about each design variable is also performed.

Taming of large diameter triaxial setup

  • Nair, Asha M.;Madhavi Latha, G.
    • Geomechanics and Engineering
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    • 제4권4호
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    • pp.251-262
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    • 2012
  • Triaxial tests are essential to estimate the shear strength properties of the soil or rock. Normally triaxial tests are carried out on samples of 38 mm diameter and 76 mm height. Granular materials, predominantly used in base/sub-base construction of pavements or in railways have size range of 60-75 mm. Determination of shear strength parameters of those materials can be made possible only through triaxial tests on large diameter samples. This paper describes a large diameter cyclic triaxial testing facility set up in the Geotechnical Engineering lab of Indian Institute of Science. This setup consists of 100 kN capacity dynamic loading frame, which facilitates testing of samples of up to 300 mm diameter and 600 mm height. The loading ram can be actuated up to a maximum frequency of 10 Hz, with maximum amplitude of 100 mm. The setup is capable of carrying out static as well as dynamic triaxial tests under isotropic, anisotropic conditions with a maximum confining pressure of 1 MPa. Working with this setup is a difficult task because of the size of the sample. In this paper, a detailed discussion on the various problems encountered during the initial testing using the equipment, the ideas and solutions adopted to solve them are presented. Pilot experiments on granular sub-base material of 53 mm down size are also presented.

프리아크 개념을 이용한 로봇의 충돌회피 동작 계획 (Collision-Free Motion Planning of a Robot Using Free Arc concept)

  • 이석원;남윤석;이범희
    • 제어로봇시스템학회논문지
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    • 제6권3호
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    • pp.317-328
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    • 2000
  • This paper presents an effective approach to collision-free motion planning of a robot in the work-space including time-varying obstacles. The free arc is defined as a set composed of the configuration points of the robot satisfying collision-free motion constraint at each sampling time. We represent this free arc with respect to the new coordinate frame centered at the goal configuration and there for the collision-free path satisfying motion constraint is obtained by connecting the configuration points of the free arc at each sampling mined from the sequence of free arcs the optimality is determined by the performance index. Therefore the complicated collision-free motion planning problem of a robot is transformed to a simplified SUB_Optimal Collision Avoidance Problem(SOCAP). We analyze the completeness of the proposed approach and show that it is partly guaranteed using the backward motion. Computational complexity of our approach is analyzed theoretically and practical computation time is compared with that of the other method. Simulation results for two cally and practical computation time is compared with that of the other method. Simulation results for two SCARA robot manipulators are presented to verify the efficacy of the proposed method.

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Quasiclassical Trajectory Calculations for the Reaction Ne + H2+ → NeH+ + H

  • Wang, Yuliang;Tian, Baoguo;Qu, Liangsheng;Chen, Juna;Li, Hui
    • Bulletin of the Korean Chemical Society
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    • 제32권12호
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    • pp.4210-4214
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    • 2011
  • Quasiclassical trajectory (QCT) calculations of Ne + ${H_2}^+$ reaction have been carried out on the adiabatic potential energy surface of the ground state $1^2$ A'. The reaction probability of the title reaction for J = 0 has been calculated, and the QCT result is consistent with the previous quantum mechanical wave packet result. Quasiclassical trajectory calculations of the four polarization-dependent differential cross sections have been carried out in the center of mass (CM) frame. The P(${\theta}_r$), P(${\phi}_r$) and P(${\theta}_r$, ${\phi}_r$) distributions, the k-k'-j' correlation and the angular distribution of product rotational vectors are presented in the form of polar plots. Due to the well in $1^2$ A' PES, the reagent vibrational excitation has greater influence on the polarization of the product rotational angular momentum vectors j' than the collision energy.

TiO2 membrane를 이용한 수소 동위원소 분리

  • 이재원;이현권;남건우;이기영
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2017년도 춘계학술대회 논문집
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    • pp.147-147
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    • 2017
  • $TiO_2$는 의료기기, 광촉매, 태양전지 등의 여러 분야에 응용이 가능하여 많은 연구가 진행되어 왔다. 그 중 양극산화를 통하여 수직으로 잘 정렬된 나노튜브는 넓은 반응면적, 높은 전자 전도성 등의 장점으로 그 성능을 더욱 향상 시킬 수 있어 많은 연구자들이 이용하고 있다. 양극산화의 특성상 Ti 기판 위에 형성된 나노튜브의 효용성을 높이기 위하여 기판에서 분리하여 membrane의 형태로 이용하기도 한다. 이런 $TiO_2$ 나노튜브 멤브레인의 이용은 주로 오염물의 분해를 위한 광촉매, 염료감응 태양전지의 전극으로 이용되고 있다. 본 연구는 $TiO_2$ 나노튜브 멤브레인에 기체 동위 원소 분리에 이용되는 HKUST-1, ZIF-8 등과 같은 Metal Organic Frame Work (MOF)을 충진 시켜 극저온에서 수소 동위 원소를 분리 하고 자 하는데 있다. 하지만 MOF를 충진하기 위해서는 기존의 $TiO_2$ 나노 튜브 멤브레인보다 더 넓은 내경과 안정성이 요구되는 바이다. 이를 위하여 본 연구에서는 내경을 수백 나노미터 이상으로 확장하기 위한 전해질, 전류(전압) 조건 등에 대하여 연구 하였다. 또한 멤브레인의 안정적인 제조를 위하여 2-step 양극산화 조건, 열처리 조건 등의 변화를 통하여 그 목적을 달성 하고자 하였다.

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