• 제목/요약/키워드: theory

검색결과 33,016건 처리시간 0.05초

Government-Nonprofit Service Delivery from Resource Dependence Theory: Revising with System Dynamics

  • Cho, Sung-Sook
    • 한국시스템다이내믹스연구
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    • 제8권1호
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    • pp.5-24
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    • 2007
  • This study explores the partnership between government and human service nonprofits in the United States from the perspective of resource dependence theory and extends the theory with system dynamics in order to better explain government-nonprofit service delivery. The article is structured as follows. First, I introduce the historical development of the government-nonprofit partnership in service delivery in the United States. Second, I present an overview of resource dependence theory for government-nonprofit service delivery, including assumptions, key elements, claims, how well it explains the government-nonprofit service delivery, and limitations. Third, I highlight the advantages of system dynamics along with the limitations of resource dependence theory, as an attempt to revise the theory. Finally, I conclude with a summary and suggestions for the next steps in theoretical development and research.

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불규칙 접촉하중에서의 피로한도에 관한 연구 (Study on the fatigue Limit at Random Contact Loading)

  • 옥영구;안득만;조용주;이현우
    • 한국정밀공학회지
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    • 제19권8호
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    • pp.84-91
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    • 2002
  • This paper analyzes the subsurface stress at the spherical contact using Hamilton equation, and with that data, calculates the fatigue limit under the variations of friction coefficient using fatigue theory. After rough surface being made, this paper figures out the random load generated by contacting to the rough surface, analyzes the stress of its subsurface, and calculates the fatigue limit of the rough surface using fatigue theory. The three parts of the fatigue theory are applied, which are critical plane theory, stress invariant theory and mesoscopic theory.

Free vibration analysis of a three-layered microbeam based on strain gradient theory and three-unknown shear and normal deformation theory

  • Arefi, Mohammad;Zenkour, Ashraf M.
    • Steel and Composite Structures
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    • 제26권4호
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    • pp.421-437
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    • 2018
  • Free vibration analysis of a three-layered microbeam including an elastic micro-core and two piezo-magnetic face-sheets resting on Pasternak's foundation are studied in this paper. Strain gradient theory is used for size-dependent modeling of microbeam. In addition, three-unknown shear and normal deformations theory is employed for description of displacement field. Hamilton's principle is used for derivation of the governing equations of motion in electro-magneto-mechanical loads. Three micro-length-scale parameters based on strain gradient theory are employed for prediction of vibrational characteristics of structure in micro-scale. The results show that increase of three micro-length-scale parameters leads to significant increase of three natural frequencies especially for increase of second micro-length-scale parameter. This result is according to this fact that stiffness of a micro-scale structure is increased with increase of micro-length-scale parameters.

고차전단변형을 고려한 복합적층판 및 쉘구조의 좌굴해석 (Buckling Analysis of Laminated Composite Plate and Shell Structures considering a Higher-Order Shear Deformation)

  • 이원홍;윤석호;한성천
    • 한국강구조학회 논문집
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    • 제9권1호통권30호
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    • pp.3-11
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    • 1997
  • Laminated composite shells exhibit properties comsiderably different from those of the single-layer shell. Thus, to obtain the more accurate solutions to laminated composite shells ptoblems, effects of shear strain should be condidered in analysis of them. A higher-order shear deformation theory requires no shear correction coefficients. This theory is used to determine the buckling loads of elastic shells. The theory accounts for parabolic distribution of the transverse shear through the thickness of the shell and rotary inertia. Exact solutions of simply-supported shells are obtained and the results are compared with the exact solutions of the first-order shear deformation theory, and the classical theory. The present theory predicts the buckling loads more accurately when compared to the first -order and classical theory.

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기하양식과 2차원적 각색 : 알로이스 리글(Alois Riegl)의 시지각이론과 비엔나 아르누보 건축 (Geometric Style and Two-Dimensional Transformation : Alois Riegl's Theory of Visual Perception and Vienna Art Nouveau Architecture)

  • 임석재
    • 건축역사연구
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    • 제3권2호
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    • pp.125-141
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    • 1994
  • Alois Riegl's aesthetic theory of visual perception provided one of important conceptual backgrounds for Vienna Art Nouveau architecture. Riegls theory of visual perception consists of geometric style and two-dimensional transformation. Riegl's theory of geometric style is based on the modern aesthetic theory of abstraction, which says that the artistic perfection can be obtained not from a direct imitation of natural objects, but from an abstract transformation of them. Riegl's theory of two-dimensional transformation, on the other hand, aims at obtaining artistic perfection by disintegrating volumetric conditions of natural things into planes and combining the planes thus obtained into another new world of art. These two theories of Alois Rigl's provided an important aesthetical background for the design strategy of 'abstract ornamentaion of two-dimension' in Vienna Art Nouveau architecture. This paper is to review the basic concept of Alois Rigl's theory of geometric style and two-dimensional transformation.

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구형 압입이론에 관한 고찰 (Some Remarks on the Spherical Indentation Theory)

  • 이진행;이형일;송원근
    • 대한기계학회논문집A
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    • 제25권4호
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    • pp.714-724
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    • 2001
  • In this work, some inaccuracies and limitation of prior indentation theory, which is based on the deformation theory of plasticity and experimental observations, are first investigated. Then effects of major material properties on the configuration of indentation load-deflection curve are examined via incremental plasticity theory based finite element analyses. It is confirmed that subindenter deformation and stress-strain distribution from the deformation theory of plasticity are quite dissimilar to those from incremental theory of plasticity. We finally suggest the optimal data acquisition location, where the strain gradient is the least and the effect of friction is negligible. This data acquisition point increases the strain range by a factor of five.

A novel and simple higher order shear deformation theory for stability and vibration of functionally graded sandwich plate

  • Sekkal, Mohamed;Fahsi, Bouazza;Tounsi, Abdelouahed;Mahmoud, S.R.
    • Steel and Composite Structures
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    • 제25권4호
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    • pp.389-401
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    • 2017
  • In this work, a new higher shear deformation theory (HSDT) is developed for the free vibration and buckling of functionally graded (FG) sandwich plates. The proposed theory presents a new displacement field by using undetermined integral terms. Only four unknowns are employed in this theory, which is less than the classical first shear deformation theory (FSDT) and others HSDTs. Equations of motion are obtained via Hamilton's principle. The analytical solutions of FG sandwich plates are determined by employing the Navier method. A good agreement between the computed results and the available solutions of existing HSDTs is found to prove the accuracy of the developed theory.

Single variable shear deformation model for bending analysis of thick beams

  • Abdelbari, Salima;Amar, Lemya Hanifi Hachemi;Kaci, Abdelhakim;Tounsi, Abdelouahed
    • Structural Engineering and Mechanics
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    • 제67권3호
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    • pp.291-300
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    • 2018
  • In this work, a new trigonometry theory of shear deformation is developed for the static analysis of thick isotropic beams. The number of variables used in this theory is identical to that required in the theory of Euler-Bernoulli, sine function is used in the displacement field in terms of the coordinates of the thickness to represent the effects of shear deformation. The advantage of this theory is that shear stresses can be obtained directly from the relationships constitute, while respecting the boundary conditions at the free surface level of the beam. Therefore, this theory avoids the use of shear correction coefficients. The differential equilibrium equations are obtained using the principle of virtual works. A thick isotropic beam is considered, whose numerical study to show the effectiveness of this theory.

$\ll$황제내경(黄帝内经)$\gg$ 장상학리론체계적주요내용여결구간석(藏象学理论体系的主要内容与结构简析) (Analysis of the main contents and structure of the visceral manifestation theoretical systems in "Hwangjenaegyeong(黃帝內經)")

  • 장우붕
    • 대한한의학원전학회지
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    • 제23권1호
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    • pp.125-128
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    • 2010
  • The visceral manifestation theory in the "Hwangjenaegyeong(黃帝內經)" was constructed by the reference of the study of Confucian classics which main characteristics is the extensive application of the five phase theory. "Image" plays an important role in the thinking of the Chinese ancient people and it is the basis of the construction of the visceral manifestation theory. "Concept of holism" is the main directed thinking of the "Hwangjenaegyeong(黃帝內經)" "Four seasons, five viscera, Yin yang" theory is the core contents of the visceral manifestation theory in the "Hwangjenaegyeong(黃帝內經)".

변형 및 증분소성이론에 따른 압입특성 비교 (Comparison of Indentation Characteristics According to Deformation and Incremental Plasticity Theory)

  • 이진행;이형일
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2000년도 추계학술대회논문집A
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    • pp.177-184
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    • 2000
  • In this work, some inaccuracies and limitation of prior indentation theory, which is based on the deformation theory of plasticity and experimental observations, are first investigated. Then effects of major material properties on the configuration of indentation load-deflection curve are examined via incremental plasticity theory based finite element analyses. It is confirmed that subindenter deformation and stress-strain distribution from the deformation theory of plasticity are quite dissimilar to those from incremental theory of plasticity. We finally suggest the optimal data acquisition location, where the strain gradient is the least and the effect of friction is negligible. This data acquisition point increases the strain range by a factor of five.

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