• Title/Summary/Keyword: domain structure

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Domain Structures of LiNbO3 Single Crystals Grown by Czochralski Method (Czochralski법에 의해 성장시킨 LiNbO3단결정의 Domain Structure)

  • 최종건;오근호
    • Journal of the Korean Ceramic Society
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    • v.25 no.6
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    • pp.699-703
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    • 1988
  • Domain structures of LiNbO3 crystals grown by Czochralski method were examined according to the growth axis and the rotational speed of crystals. Ring shape and split domain structures were revealed in Z-axis and Y-axis grown crystals respectively. It was found that the domain structures of grown crystals were closely related to the solid-liquid interface shape during growth.

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Nonlinear Seismic Response Analysis for Shallow Soft Soil Deposits (낮은 심도의 연약지반에 대한 비선형 지진응답해석)

  • Park, Hong-Gun;Kim, Dong-Kwan;Lee, Kyung-Koo;Kim, Dong-Soo
    • Journal of the Earthquake Engineering Society of Korea
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    • v.14 no.5
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    • pp.1-12
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    • 2010
  • This study presents a finite element analysis method that can accurately evaluate the nonlinear behaviour of structures affected by shallow soft subsoils and the soil-structure interaction. A two-dimensional finite element model that consists of a structure and shallow soft subsoil was used. The finite element model was used for a nonlinear time domain analysis of the OpenSees program. A parametric study was performed to investigate the effects of soil shear velocities, earthquake input motions, soft soil depth, and soil-structure interaction. The result of the proposed nonlinear finite element analysis method was compared with the result of an existing frequency domain analysis method, which is frequently used for addressing nonlinear soil behavior. The result showed that the frequency domain analysis, which uses equivalent secant soil stiffness and does not address the soil-structure interaction, significantly overestimated the response of the structures with short dynamic periods. The effect of the soil-structure interaction on the response spectrum did not significantly vary with the foundation dimensions and structure mass.

A Field Study on Global R&D Centers in Korea: Focusing on Global IT Industry Policy with Gap Approach (글로벌 R&D센터에 대한 현장조사연구: 갭접근방법에 의한 글로벌 IT산업정책중심)

  • Cho, Sang-Sup;Yang, Young-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3797-3803
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    • 2009
  • Innovative capacities and performance are essential for the growth of the IT industry and the development of the Korean economy. Global R&D centers are important sources of innovation in the IT industry. In order to identify the structure of the innovation environment of global R&D centers in IT industry, we conducted a field survey of 50 global R&D centers and 50 global R&D policy experts in IT industry. According to the empirical results obtained using the Linear Structure Model, it is suggested that, first, with regard to a short-term IT global policy, the direction of the Korean government's policy should act as a trigger to connect the research domain and the market domain; second, the government policy should act as a facilitator to connect the development domain and the research domain in the mid-term period; and, finally, the government's R&D policy should serve as a disseminator to connect technological capability and the market space domain in the long-term perspective. For an effective way of internationalizing innovation, IT policy planners should regard global IT R&D centers as the important components of national innovation system and encourage the effective involvements by them in the process of IT industrial innovation.

Development of an Infinite Element for Non-linear Dynamic Analysis of Structures (구조물의 비선형 동적 해석을 위한 무한요소의 개발)

  • Kwon, Min-Ho;Han, Gil-Woong
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.3
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    • pp.1053-1058
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    • 2010
  • Infinite element approach has been widely used to analysis soil-structure interaction, in which the soil domain is treated as infinite domain. However, most of the developed infinite element has been formulated in the frequency domain rather than the time domain to include the frequency contents of the earthquake or vibration wave. Due to that, those approaches have a critical limitation which is restricted to the linear elastic analysis. To main objective of this research is to develop the infinite element in the time domain to cooperate the inelastic soil and structure behavior. Developed infinite element is verified with the results of finite element analysis modeled in large domain. The nonlinear analysis also conducted to demonstrate the application of developed infinite element. Hence, based on above-mentioned statements, it can be concluded that the propose approach would assist for structure-seismic design.

An Identification of the Image Retrieval Domain from the Perspective of Library and Information Science with Author Co-citation and Author Bibliographic Coupling Analyses

  • Yoon, JungWon;Chung, EunKyung;Byun, Jihye
    • Journal of the Korean Society for Library and Information Science
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    • v.49 no.4
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    • pp.99-124
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    • 2015
  • As the improvement of digital technologies increases the use of images from various fields, the domain of image retrieval has evolved and become a growing topic of research in the Library and Information Science field. The purpose of this study is to identify the knowledge structure of the image retrieval domain by using the author co-citation analysis and author bibliographic coupling as analytical tools in order to understand the domain's past and present. The data set for this study is 245 articles with 8,031 cited articles in the field of image retrieval from 1998 to 2013, from the Web of Science citation database. According to the results of author co-citation analysis for the past of the image retrieval domain, our findings demonstrate that the intellectual structure of image retrieval in the LIS field consists of predominantly user-oriented approaches, but also includes some areas influenced by the CBIR area. More specifically, the user-oriented approach contains six specific areas which include image needs, information seeking, image needs and search behavior, image indexing and access, indexing of image collection, and web image search. On the other hand, for CBIR approaches, it contains feature-based image indexing, shape-based indexing, and IR & CBIR. The recent trends of image retrieval based on the results from author bibliographic coupling analysis show that the domain is expanding to emerging areas of medical images, multimedia, ontology- and tag-based indexing which thus reflects a new paradigm of information environment.

Multiple Relationships Between Impairment, Activity and Participation-based Clinical Outcome Measures in 200 Low Back Pain

  • Chanhee Park
    • Physical Therapy Korea
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    • v.30 no.2
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    • pp.136-143
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    • 2023
  • Background: The International Classification of Functioning, Disability and Health (ICF) model, created by the World Health Organization, provides a theoretical framework that can be applied in the diagnosis and treatment of various disorders. Objects: Our research purposed to ascertain the relationship between structure/function, activity, and participation domain variables of the ICF and pain, pain-associated disability, activities of daily living (ADL), and quality of life in patients with chronic low back pain (LBP). Methods: Two-hundred patients with chronic LBP (mean age: 35.5 ± 8.8 years, females, n = 40) were recruited from hospital and community settings. We evaluated the body structure/function domain variable using the Numeric Pain Rating Scale (NPRS) and Roland-Morris disability (RMD) questionnaire. To evaluate the activity domain variable, we used the Oswestry Disability Index (ODI) and Quebec Back Pain Disability Scale (QBDS). For clinical outcome measures, we used Short-form 12 (SF-12). Pearson's correlation coefficient was used to ascertain the relationships among the variables (p < 0.05). All the participants with LBP received 30 minutes of conventional physical therapy 3 days/week for 4 weeks. Results: There were significant correlations between the body structure/function domain (NPRS and RMD questionnaire), activity domain (ODI and QBDS), and participation domain variables (SF-12), rending from pre-intervention (r = -0.723 to 0.783) and postintervention (r = -0.742 to 0.757, p < 0.05). Conclusion: The identification of a significant difference between these domain variables point to important relationships between pain, disability, performance of ADL, and quality in participants with LBP.

Time Domain Seismic Response Analysis of Nonlinear Soil-Pile-Structure Interaction System using Inverse FFT of Dynamic Fundamental Solution (동적기본해의 역FFT에 의한 비선형 지반-말뚝-구조계의 시간영역 지진응답 해석)

  • 김문겸;임윤묵;조석호;박종헌;정대희
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2002.03a
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    • pp.125-132
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    • 2002
  • In this study, a numerical method is developed for nonlinear analysis for soil-pile-structure interaction system in time domain. Finite elements considering material nonlinearity are used for the near field and boundary elements for the far field. In the near field, frame elements are used for modeling a pile and plane-strain elements for surrounding soil and superstructure. In. the far field, boundary element formulation using the dynamic fundamental solution is adopted and coupled with the near field. Transformation of stiffness matrices of boundary elements into time domain is performed by inverse FFT. Stiffness matrices in the near field and far field are coupled. Newmark direct time integration method is applied. Developed soil-pile-structure interaction analysis method is verified with available literature and commercial code. Also, parametric studies by developed numerical method are performed. And seismic response analysis is performed using actual earthquake records.

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Structural Diagnosis in Time Domain on Damage Size (손상크기에 따른 시간영역에서의 구조물 진단)

  • 권대규;임숙정;방두열;이성철
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.05a
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    • pp.259-262
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    • 2002
  • This paper provides the experimental verification of a non-destructive time domain approach to examine structural damage. Time histories of the vibration response of structure were used to identify the presence of damage. Damage in a structure cause changes in the physical coefficients of mass density, elastic modulus and damping coefficient. This paper examines the use of beam like structures with PVDF sensor and PZT actuator to perform identification of those physical parameters, and hence to detect the damage. Experimental results are presented from tests on cantilevered composite beams damaged at different location and with damage of different dimensions. It is demonstrated that the method can sense the presence of damage, and characterize the damage to a satisfactory precision.

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Analyses on the Behaviour of Ocean Structure Due to Ship Collision (선박의 충돌로 인한 해양구조물의 거동 해석)

  • 이호영;박종환;곽영기
    • Journal of Ocean Engineering and Technology
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    • v.15 no.4
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    • pp.115-119
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    • 2001
  • The simulation of motion responses of a dolphin-moored ocean structure in shallow water when it cllides with a ship, has been carried out. The equation of motion in the time domain according to Cummin's theory is employed, and solved by making use of the Newmark-${\beta}$ method. The added mass and damping coefficients involved in the equations are abtained from a three-dimensional panel method in the frequency domain. The impact forces due to ship collision are calculated using both the elastic and non-elastic modelings. The mooring forces for dolphin systems of ocean structure are regarded as linear spring forces.

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Helical domain structure in laser-annealed Co-riched amorphous microwires

  • Lee, B. S.;Y. W. Rheem;Kim, C. G.;Kim, C. O.;S. S. Yoon;S. J. Ahn
    • Proceedings of the Korean Magnestics Society Conference
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    • 2002.12a
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    • pp.210-211
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    • 2002
  • The magnetic anisotropy of amorphous wires plays a decisive role in the giant magnetoimpedance(GMI) behavior. The magnetoelastic anisotropy caused by internal stress, that are frozen in during the fabrication process, results in an axial easy axis in the core region and in a circular easy axis in the shell region [1]. It leads to a simple domain structure consisting of circular domains in the shell and axial domains in the core. For a more realistic domain structure, it has been suggested that the helical anisotropy exists due to an internal helical stress [2]. (omitted)

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