• 제목/요약/키워드: research structure

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FORM 신뢰성 기반 항타강관말뚝 저항계수 산정 (FORM Reliability-based Resistance Factors for Driven Steel Pipe Piles)

  • 박재현;허정원;이주형;정문경;곽기석
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2008년도 추계 학술발표회
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    • pp.779-783
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    • 2008
  • LRFD Resistance factors for static bearing capacity of driven steel pipe piles were calibrated in the freamework of reliability theory. Reliability analysis was performed by the First Order Reliability Method (FORM) using resistance bias factor statistics.The target reliability indices are selected as 2.0 and 2.33 for group pile case and 2.5 for single pile case, based on the reliability level of the current design practice and considering redundancy of pile group, acceptable risk level, construction quality control, and significance of individual structure.

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Changes in the Modulation Amplitude and the Particle Sizes of Co/Pd Multilayers During Stress Release and Interdiffusion

  • Kim, Jai-Young;Evetts, Jan-E
    • Journal of Magnetics
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    • 제3권1호
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    • pp.21-30
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    • 1998
  • An artificially modulated magnetic Co/Pd multilayer is one of the promising candidates for high density magneto-optic (MO) recording media, due to large Kerr rotation angle in the wavelength of a blue laser beam. however, since multilayer structure, as well as amorphous structure, is a non-equilibrium state in terms of free energy and MO recording is a kind of thermal recording which is conducted aound Curie temperature (Tc) of the recording media, when the multilayer is used for the MO recording media, changes in the multilayer structure are occurred as the amorphous structure do. Therefore, the assessment of the structural stability in the Co/Pd multilayer is crucially important both for basic research and applications. As the parameter of the structural stability in this research, modulation amplitude and particle size of the Co/Pd multilayer are measured in terms of Ar sputtering pressure and heat treatment temperature. From the results of the research, we find out that the magnetic exchange energy in the structural changes of a magnetic multilayer structure and suggest the operating temperature range for MO recording in the Co/Pd multilayer for the basic research and applications, respectively.

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해저 지형을 고려한 초대형 부유체의 유탄성 거동 해석 (Numerical Study on the Hydroelastic Response of the Very Large floating Structure Considering Sea-Bottom Topography)

  • 경조현;김병완;조석규;홍사영
    • 대한조선학회논문집
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    • 제42권4호
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    • pp.357-367
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    • 2005
  • A numerical method is developed for the hydroelastic response of the Very Large Floating Structure considering the sea-bottom topography. The sea-bottom effects on the hydroelastic response of the floating structure is studied. The sea-bottom topography should be considered when the floating structure is constructed near the shore. To investigate the sea-bottom effects, four different sea-bottom topographies are considered in this study. finite-element method based on the variational formulation is used in the fluid domain, The pontoon-type floating structure is modeled as the Kirchhoff plate. The mode superposition method is adopted for the hydroelastic behavior of the floating structure.

AMOS 소프트웨어에서 구현되는 구조방정식 모형과 의미 (A Mean of Structural equation modeling on AMOS Software)

  • 김경태
    • 한국조사연구학회:학술대회논문집
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    • 한국조사연구학회 2007년도 추계학술대회 발표논문집
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    • pp.55-65
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    • 2007
  • 연구에서는 공분산구조분석을 실시하기 위해 주로 사용하고 있는 AMOS 소프트웨어에 대하여 알아보려고 한다. 응용소프트웨어에서 활용된 수학적인 모형을 알지 못하면, 구조방정식에 대한 충분한 이해를 할 수 없으며, 구조방정식에 대한 8가지 가정이 어떻게 구현되는지 알 수 가 없다. 따라서 본 연구에서는 구조방정식모형 연구에서 주로 활용되었던 LISREL 프로그램으로 RAM과 MOSAN을 구현하였고 AMOS 결과와 비교분석하였다. 연구 결과에 따르면 AMOS프로그램은 8가지의 모든 가정을 따르지 않는 것으로 나타났다. AMOS 프로그램이 MOSAN보다는 RAM으로 구현되고 있음을 본 연구를 통해 알 수 있다. AMOS 소프트웨어 프로그램은 잠재변수(F)와 측정오차(e)간의 상관값을 산출할 때 충분히 추정을 하지 못하고 부분적으로만 추정하여 값을 산출하고 있음을 알 수 있었다.

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The effect of field-line twist on the dynamic and electric current structures of emerging magnetic field on the Sun

  • An, Jun-Mo;Lee, Hwan-Hee;Kang, Ji-Hye;Magara, Tetsuya
    • 천문학회보
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    • 제36권2호
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    • pp.102.1-102.1
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    • 2011
  • In this study we use three-dimensional magnetohydrodynamic simulations to investigate how the dynamic state of emerging magnetic field is related to the twist of field lines. Emerging magnetic field forms a magnetic structure on the Sun where various kinds of activity such as solar flares, jets, and coronal mass ejections are observed. To understand the physical mechanism for producing such activity, we have to know the dynamic nature of this structure. Since flares are the manifestation of rapidly dissipating electric current in the corona, we also investigate the distribution of current density inside the structure and examine how it depends on the field-line twist. To demonstrate the dynamic structure of emerging magnetic field, we focus on the factors characterizing the geometric property and stratification of emerging magnetic field, such as the curvature of field line and the scale height of field strength. These two factors show that emerging field forms a two-part structure in which the central part is close to a force-free state while the outer marginal part is in a fairly dynamic state where magnetic pressure force is dominant. We discuss how the field-line twist affects the two-part structure and also explain a possible relation between electric current structure and sigmoid observed in a preflare phase.

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Reciprocal Capital Structure and Liquidity Policy: Implementation of Corporate Governance toward Corporate Performance

  • SUMANI, Sumani;ROZIQ, Ahmad
    • The Journal of Asian Finance, Economics and Business
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    • 제7권9호
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    • pp.85-93
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    • 2020
  • The research objective examines the effect of corporate governance on capital structure and its effect on liquidity policy and corporate performance. It tests the effect of capital structure and liquidity policy on corporate governance. It also examines the effect of liquidity policy on capital structure and the effect of capital structure on liquidity policy. The study population is all manufacturing companies that went public on the Indonesia Stock Exchange in the period 2010-2019. The research population is 182 manufacturing companies. The Judgment Sampling was used and 109 companies meet the research criteria. The study used panel data for ten years so that the amount of data observed was 1090 observations. The analysis tool uses Warp Partial Least Square (WarpPLS). The results showed that corporate governance had a significant positive effect on capital structure, but corporate governance had a significant adverse effect on liquidity policy, and corporate governance had a significant positive effect on corporate performance. Furthermore, capital structure has a significant negative effect on corporate performance, but liquidity policy has no significant effect on corporate performance. Capital structure and liquidity policy are proven to be reciprocally significant positive correlations for manufacturing companies in Indonesia.

동화사 수마제전의 건축적 특징 (Architectural Characteristic of SooMaJaiJeon in DongHwaSa)

  • 이경수
    • 한국산업융합학회 논문집
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    • 제26권1호
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    • pp.69-78
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    • 2023
  • For this purpose, the research is to study the architectural characteristic of SooMaJaiJeon which is one of the DongHwaSa in the traditional wooden architecture by dividing it into three section-bracket, roof structure and frame structure. This study is largely divided into four stage-section do subject, research and actual measurement and conclusion. The whole process was consistently executed through detailed steps. The com position of this study is as follows. The 1st chapter-the purpose, background, method, object and range of the research. The 2nd chapter-the history of SooMajaiJeon. the 3rd chapter-the structure of Dapo-style bracket has generally considered, the frame structure of Dapo-style, vertical and horizontal member and podium, the characteristic of bracket with member and the structure, design of bracket, roof structure. In the 4th chapter, the conclusion of this study has been summarized, Dapo-style is the building that has deep symbolism and structural characteristic of traditional wooden architecture. The frame structure has a dominant regional characteristic and a typical part of typological classification in SooMaJaiJeon.

축소모델을 이용한 구조체 접지 분석 (The Analysis of Structure Grounding Using Reduced Scale Model)

  • 길형준;김향곤;한운기;이기연;최충석
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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    • pp.2046-2048
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    • 2005
  • This paper deals with ground potential rise of structure grounding electrode when a test current flows through grounding electrode. In order to analyze the potential gradient of ground surface on structure grounding electrode, the reduced scale model has been used. The structures were designed through reducing real buildings and fabricated with four types on a scale of one-one hundred sixty. The supporter was made to put up with weight of structure and could move into vertical, horizontal, rotary direction. When a test current flowed through structure grounding electrodes, ground potential rise was the lowest value at electric cage type(type B). According to resistivity and absorption percentage in concrete attached to structure, the potential distribution of ground surface appeared differently.

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공학소양교육 사례로서의 DNA 구조 발견 (Discovery of the DNA double helix structure as a model of Liberal Education for Engineers)

  • 남영
    • 공학교육연구
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    • 제21권6호
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    • pp.54-62
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    • 2018
  • This study is an analysis of the process of the discovery of the DNA double helix structure from an engineering literacy education perspective. The explanation of the DNA double helix structure by James Watson and Francis Crick in 1952 is a well-known scientific episode. The process is also a combination of various incidents that can frequently happen in competitive engineering research and development situations. Therefore, the process of the discovery of the DNA structure is a remarkable event that can cover all subjects, such as engineering and ethics, research ethics, communication between researchers, engineering and leadership, engineering and teamwork, and engineering and women. This paper focuses on analyzing the research ethics issues associated with Rosalind Franklin and comparing and analyzing the three teams that were very close to the discovery of the DNA structure. By looking at why the Watson and Crick team got the final answer instead of the Linus Pauling's team or the Maurice Wilkins and Rosalind Franklin's team, the virtues of the technology development process that should be taught in engineering literacy education will be naturally presented.

Structural noise mitigation for viaduct box girder using acoustic modal contribution analysis

  • Liu, Linya;Qin, Jialiang;Zhou, Yun-Lai;Xi, Rui;Peng, Siyuan
    • Structural Engineering and Mechanics
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    • 제72권4호
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    • pp.421-432
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    • 2019
  • In high-speed railway (HSR) system, the structure-borne noise inside viaduct at low frequency has been extensively investigated for its mitigation as a research hotspot owing to its harm to the nearby residents. This study proposed a novel acoustic optimization method for declining the structure-borne noise in viaduct-like structures by separating the acoustic contribution of each structural component in the measured acoustic field. The structural vibration and related acoustic sourcing, propagation, and radiation characteristics for the viaduct box girder under passing vehicle loading are studied by incorporating Finite Element Method (FEM) with Modal Acoustic Vector (MAV) analysis. Based on the Modal Acoustic Transfer Vector (MATV), the structural vibration mode that contributes maximum to the structure-borne noise shall be hereinafter filtered for the acoustic radiation. With vibration mode shapes, the locations of maximum amplitudes for being ribbed to mitigate the structure-borne noise are then obtained, and the structure-borne noise mitigation performance shall be eventually analyzed regarding to the ribbing conduction. The results demonstrate that the structural vibration and structure-borne noise of the viaduct box girder mainly occupy both in the range within 100 Hz, and the dominant frequency bands both are [31.5, 80] Hz. The peak frequency for the structure-borne noise of the viaduct box girder is mainly caused by $16^{th}$ and $62^{th}$ vibration modes; these two mode shapes mainly reflect the local vibration of the wing plate and top plate. By introducing web plate at the maximum amplitude of main mode shapes that contribute most to the acoustic modal contribution factors, the acoustic pressure peaks at the field-testing points are hereinafter obviously declined, this implies that the structure-borne noise mitigation performance is relatively promising for the viaduct.