• 제목/요약/키워드: Knowledge Structures

검색결과 715건 처리시간 0.03초

척추의 3차원 수학적 척추 모델 개발 (Developement of Three-Dimensional Mathematical Spinal Model)

  • 한정수;안태정;이태희
    • 대한의용생체공학회:의공학회지
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    • 제21권2호
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    • pp.189-201
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    • 2000
  • Mechanical factors in the human body are considered to play a dominant role in low back problems. Various spinal structures. including muscles, act in unison to resist the external load. An estimation of the muscle forces in this structure requires a knowledge of the orientation, location and area of cross-section of the muscles to complete the formulation of a truly three-dimensional mathematical model of the spine. The geometric parameters which are calculated were the line of action, the centroid and physiologic area of cross-section of each muscle as a function of the spinal level. This geometric data were obtained from CT scans of 11 subjects participating in this study.

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Seismicity of Peninsular Malaysia due to intraplate and far field sources

  • Loi, Daniel W.;Raghunandan, Mavinakere E.;Swamy, Varghese
    • Earthquakes and Structures
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    • 제10권6호
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    • pp.1391-1404
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    • 2016
  • Peninsular Malaysia lying on the stable Sunda Plate has traditionally been considered safe with low to moderate seismicity. However, far field Sumatran mega-earthquakes have been shown to be capable of triggering ground motions felt in high rise structures in the major Malaysian cities while seismic impact from local earthquakes of moment magnitude 3.8 have reportedly induced nominal structural damages to nearby buildings. This paper presents an overview of the recent seismic activities in and around Peninsular Malaysia with reference to prominent earthquakes generated by far field interplate and local intraplate sources. Records of ground motion data and seismic hazard assessment (SHA) results available in the literature have been analyzed and discussed. The peak ground acceleration (PGA) values from historical records for few local intraplate events were observed to be higher than those for the events from Sumatran Subduction Zone. This clearly points to the need for a detailed and comprehensive SHA incorporating both far field and local sources. Such an analysis would contribute the knowledge required for secure and reliable infrastructure design and safeguard the Malaysian people and economy.

Joints: the weak link in bridge structures and lifecycles

  • Yanev, Bojidar
    • Smart Structures and Systems
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    • 제15권3호
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    • pp.543-553
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    • 2015
  • The condition of the vehicular bridge network in New York City, as represented by ratings obtained during biennial inspections is reviewed over a period of three decades. Concurrently, the bridges comprising the network are considered as networks of structural elements whose condition defines the overall bridge condition according to New York State assumptions. A knowledge-based matrix of assessments is used in order to determine each element's vulnerability and impact within the network of an individual structure and the network of City bridges. In both networks expansion deck joints emerge as the weak link. Typical joint failures are illustrated. Bridge management options for maintenance, preservation, rehabilitation and replacement are examined in the context of joint performance.

Experimental and numerical assessment of EBF structures with shear links

  • Caprili, Silvia;Mussini, Nicola;Salvatore, Walter
    • Steel and Composite Structures
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    • 제28권2호
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    • pp.123-138
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    • 2018
  • Eccentrically braced frames (EBF) represent an optimal structural solution for seismic prone areas, being able to provide high dissipative capacity and good elastic stiffness, to withstand strong seismic events without significant loss of bearing capacity and to avoid damage to non-structural elements in case of low and moderate earthquakes. The accurate knowledge of the cyclic behaviour of the dissipative links, characterizing the whole performance of EBFs, is required to optimize the structural properties and to refine the design techniques adopted for multi-storey buildings' analysis. Reliable numerical models for the links, at the same time requiring a limited computational effort, are then needed. The present work shows the results of a wide experimental test campaign executed on real-scale one storey/one bay frames with horizontal and vertical links, together with the elaboration of a simple semi-analytical model for the quick representation of the cyclic behaviour of shear links.

Damage assessment of composite structures using Particle Swarm Optimization

  • Jebieshia, T.R.;Maiti, D.K.;Maity, D.
    • International Journal of Aerospace System Engineering
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    • 제2권2호
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    • pp.24-28
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    • 2015
  • Composite materials are highly sensitive to the presence of manufacturing and service-related defects that can reach a critical size during service condition and thereby may affect the safety of the structure. When the structure undergoes some kind of damage, its stiffness reduces, in turn the dynamic responses change. In order to avoid safety issues early detection of damage is necessary. The knowledge of the vibration behavior of a structure is necessary and can be used to determine the existence as well as the location and the extent of damage.

Winkler모델을 이용한 동바리의 시간의존적 축력 해석법 (Analysis of Time-dependent Axial Force of Shores using the Winkler Model)

  • 우창훈;김선영;이수곤
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 2002년도 봄 학술발표회 논문집
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    • pp.27-34
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    • 2002
  • In the case of reinforced concrete structures, the knowledge of load transfer in the long-term behavior analysis considering construction sequence is very important. Even though long-term behavior of concrete structures has been widely studied, the studies on the time-dependent axial force variation of shore have been scarce to date. In order to investigate the shore behaviors under actual construction conditions, a three-story test frame was constructed on a construction site. The entire construction schedule for the test frame was made to follow the schedule of an actual three-story frame. To analyze the data collected from the test frame, an analysis method based on the Winkler foundation model was developed. This analysis method accurately Predicts the time-dependent behavior of shore. The analysis results coincide well with those obtained by the Midas GENw program

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A Study to Derive Energetics of Coronal Magnetic Structures

  • 강지혜;;;이환희;안준모
    • 천문학회보
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    • 제37권2호
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    • pp.127.2-127.2
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    • 2012
  • Space weather prediction related to flares and CMEs is an important issue these days. It is, however, hard to estimate magnetic energy of invisible coronal magnetic structure. The virial theorem is one of the ways to determine the magnetic energy. In this study, we performed a series of MHD simulation of an emerging flux tube and apply the virial theorem to the simulation results and derive energetics of coronal structures. We then analyze real observational data on NOAA 11302 to derive the distributions of physical quantities, such as density, temperature, velocity and magnetic field. We also use knowledge form simulation analysis to estimate the magnetic energy of NOAA 11302.

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발목 관절경: 해부학, 삽입구 및 기구 (Ankle Arthroscopy: Anatomy, Portals and Instrument)

  • 성기선
    • 대한족부족관절학회지
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    • 제16권1호
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    • pp.1-8
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    • 2012
  • Major technologic advances in fiberoptic light transmission, video cameras, and instrumentation have allowed great advances in small-joint arthroscopy. Arthroscopy in particular is now well established procedure for accurate diagnosis and operative management of certain ankle disorders. The small size of the ankle and significant periarticular soft tissue structures make placement and advancement of the arthroscope and instrumentation more difficult than in larger joints. Successful arthroscopy of the ankle requires knowledge of the regional anatomy and a familiarity with the available arthroscopic portals. This review article is going to describe the gross and arthroscopic anatomy of the ankle as it relates to current arthroscopic techniques. Particular emphasis is placed on the anatomic relations of the important osseous and soft tissue structures for a safe, reproducible approach to arthroscopic treatment of ankle pathology. Also, current arthroscopic equipment and instruments are included.

CNN 구조의 진화 최적화 방식 분석 (Analysis of Evolutionary Optimization Methods for CNN Structures)

  • 서기성
    • 전기학회논문지
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    • 제67권6호
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    • pp.767-772
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    • 2018
  • Recently, some meta-heuristic algorithms, such as GA(Genetic Algorithm) and GP(Genetic Programming), have been used to optimize CNN(Convolutional Neural Network). The CNN, which is one of the deep learning models, has seen much success in a variety of computer vision tasks. However, designing CNN architectures still requires expert knowledge and a lot of trial and error. In this paper, the recent attempts to automatically construct CNN architectures are investigated and analyzed. First, two GA based methods are summarized. One is the optimization of CNN structures with the number and size of filters, connection between consecutive layers, and activation functions of each layer. The other is an new encoding method to represent complex convolutional layers in a fixed-length binary string, Second, CGP(Cartesian Genetic Programming) based method is surveyed for CNN structure optimization with highly functional modules, such as convolutional blocks and tensor concatenation, as the node functions in CGP. The comparison for three approaches is analysed and the outlook for the potential next steps is suggested.

Aluminum Oxide Nano-Rings Synthesized by Electrospinning Techniques

  • 조준모;박주연;고성위;김돈;강용철
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2009년도 제38회 동계학술대회 초록집
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    • pp.102-102
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    • 2010
  • One or two-dimensional nanostructures such as nanowires or nanomats have been widely uses as building blocks for nanoscale electronic devices. Nanofiber is one of sub-category of nano structures, it is easy to make nano-sized fiber by electrospinning technique. Nanofiber has large surface area as compared with their volume, it could be widely applied to many areas easily. Electrospinning technique is easy to control their structures and morphology safely and cost-effectively. We made nano-rings as a model of one dimensional nanostructures by electrospinning technique. To our knowledge, there were no reports on the preparation and investigation of alumina nano-rings by electrospinning technique. In this study, aluminum oxide nano-rings were produced after electospinning and calcination. The synthesized aluminum oxide nano-rings were characterized by scanning electron microscopy (SEM) to identify the morphology and the diameter of the ring, X-ray diffraction (XRD) to verify the crystallinity of the aluminum oxide, and X-ray photoelectron spectroscopy (XPS) for investigation of the chemical nature of the synthesized nano-rings.

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