• 아태비즈니스연구
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• 제12권3호
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• pp.87-99
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• 2021

Purpose - In this study, I attempt to clarify three theories of firm boundaries (vertical integration): the principal-agent theory, transaction cost theory, and property rights theory. Although these theories have been widely cited and much discussed, it has been found that understanding the commonalities and distinctions of these seemingly familiar theories is difficult. Design/methodology/approach - I present the three theories about the decisions that firms make concerning their boundaries. Then, I compare elemental versions of the theories of the firm. Findings - Comparing the ingredients of the elemental property rights and principal-agent theories shows that they provide a unified account of the costs and benefits of vertical integration. However, the property rights theory in no sense formalizes the transaction cost theory. Research implications or Originality - Clarifying the three theories of the firm can help to construct empirical models and interpret its results.

• 한국정보통신학회논문지
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• 제15권5호
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• pp.1171-1176
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• 2011

본 논문에서는 주기적으로 배치된 렌즈 배열을 이용한 광학 픽업과 평면기반 컴퓨터 집적 영상 복원 (CIIR) 기술에서 요소 영상 크기와 3차원 물체의 복원 깊이 위치에 따른 복원 성능에 대한 분석을 제시한다. 주기적으로 배치된 렌즈 배열에서는 3차원 물체를 픽업할 때 주기성으로 인한 희박 표본화가 발생함이 보고된다. 또한 희박 표본화가 발생하는 3차원 물체의 위치는 요소 영상의 크기와 관계식을 제시한다. 희박 표본화를 회피하는 방안을 제시하고, 이론의 평가를 위해서 컴퓨터 실험을 진행했고 그 결과는 이론을 잘 뒷받침함을 보였다.

• 지구물리와물리탐사
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• 제22권3호
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• pp.149-159
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• 2019

암석구성성분검층(중성자-감마스펙트로스코피검층)은 중성자선원의 비탄성산란과 중성자포획 작용으로부터 생성되는 감마선을 측정하여 지층의 원위치 광물조성을 추정할 수 있는 기술이다. 일반적으로 지층의 광물조성 평가는 코어에 대한 X선 회절법, X선 형광분석법 등의 실내 시험자료를 주로 이용하고 있으나 이는 조사 구간의 극히 일부분에 대한 결과이며 특히, 유체의 유동 경로 구간은 주로 파쇄대 및 사질층인데 이 구간들의 코어 회수율이 불량하여 조사 구간 전체에 대한 광물조성 평가는 한계가 있다. 따라서 시추공 전 구간에 대한 원위치 광물조성 추정 기술개발은 지중환경 평가에 중요한 역할을 할 수 있다. 이 기술은 전통, 비전통 저류층 평가를 중심으로 최근까지 장비 개발 및 관련 연구가 활발히 진행되고 있는 분야이지만 몇 개 서비스회사의 독점기술로 자세한 정보 미공개, 다양한 지층 및 인공모형을 이용한 화학-광물학 데이터베이스 구축 문제 등으로 국내 연구에 직접적으로 적용하기에는 어려움이 있었다. 이 해설논문에서는 암석구성성분검층의 기본원리, 시스템 구성, 교정시설, 국외 기 개발된 검층시스템 분석 및 연구개발 동향 등을 통해 해당 기술을 소개하고, 국내 시스템 제작을 위한 기술 적용 방안을 검토하였다.

• Nuclear Engineering and Technology
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• 제28권1호
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• pp.44-55
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• 1996

원자력 발전소에서 방사성 요오드를 제거하기 위해 사용되는 원료활성탄과 2%, 5%TEDA(Triethylene-Diamine) 첨착활성탄을 이용하여 원소요오드와 유기요오드인 메틸요오드에 대한 흡착특성을 분석하였다. 여러 흡착 등온식을 선정하여 실험치와 비교함으로서 선정된 흡착 등온식의 적합성 여부를 검증하였다. 흡착평형 실험결과 Dubinin-Astakhov(DA) 등온식이 여러 가지 흡착등온식 가운데 가장 적합한 것으로 나타났다. 흡착표면의 흡착에너지 분포가 불균일(Heterogeneous)하기 때문에 포텐셜 (Potential) 에너지를 근거로 하는 DA등온식이 흡착평형 관계를 보다 정확하게 나타내는 것으로 생각된다. 흡착표면의 불균일성을 확인하기 위해 흡착에너지 분포도를 원료활성탄과 첨착활성탄에 대해 상호 비교하였다 활성탄-요오드 흡착시스템에서 불균일성은 활성탄의 기공구조 분만 아니라 흡착질과 활성탄과의 상호관계에 의해서도 영향을 받게된다 따라서 흡착표면의 불균일성은 활성탄을 첨착함에 따라서 증가하게 되고 원소요오드보다 유기요오드의 경우 불균일성이 더 커지는 것으로 보여진다.

• Steel and Composite Structures
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• 제50권3호
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• pp.299-318
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• 2024

The main objective of this paper is to compute the far-field acoustic radiation (sound radiation) of functionally graded plates (FGM) loaded by sinusoidally varying point load subjected to the arbitrary boundary condition is carried out. The governing differential equations for thin functionally graded plates (FGM) are derived using classical plate theory (CPT) and Rayleigh integral using the elemental radiator approach. Four cases, segregated on power-law index k=0,1,5,10, are studied. A novel approach is illustrated to compute sound fields of vibrating FGM plates using the physical neutral surface with an elemental radiator approach. The material properties of the FGM plate for all cases are calculated considering the power law indexes. An in-house MATLAB code is written to compute the natural frequencies, normal surface velocities, and sound radiation fields are analytically calculated using semi-analytical formulation. Ansys is used to validate the computed sound power level. The parametric effects of the power law index, modulus ratios, different constituent of FGM plates, boundary conditions, damping loss factor on the sound power level, and radiation efficiency is illustrated. This work is the benchmark approach that clearly explains how to calculate acoustic fields using a solid layered FGM model in ANSYS ACT. It shows that it is possible to asymptotically stabilize the structure by controlling the intermittent layers' stiffness. It is found that sound fields radiated by the elemental radiators approach in MATLAB, ANSYS and literatures are in good agreement. The main novelty of this research is that the FGM plate is analyzed in the low-frequency range, where the stiffness-controlled region governs the whole analysis. It is concluded that a clamped mono-ceramic FGM plate radiates a lesser sound power level and higher radiation efficiency than a mono-metallic or metal-rich FGM plate due to higher stiffness. It is found that change in damping loss factor does not affect the same constituents of FGM plates but has significant effects on the different constituents of FGM plates.

• Steel and Composite Structures
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• 제45권3호
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• pp.331-348
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• 2022

The main goal of this article is to develop the finite element formulation based on the nonlocal strain gradient and the refined higher-order deformation theory employing a new function f(z) to investigate the static bending and free vibration of functionally graded porous (FGP) nanobeams. The proposed model considers the simultaneous effects of two parameters: nonlocal and strain gradient coefficients. The nanobeam is made by FGP material that exists in un-even and logarithmic-uneven distribution. The governing equation of the nanobeam is established based on Hamilton's principle. The authors use a 2-node beam element, each node with 8 degrees of freedom (DOFs) approximated by the C¹ and C² continuous Hermit functions to obtain the elemental stiffness matrix and mass matrix. The accuracy of the proposed model is tested by comparison with the results of reputable published works. From here, the influences of the parameters: nonlocal elasticity, strain gradient, porosity, and boundary conditions are studied.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1697-1702
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• 2014

A novel complex [$Zn(phen)(o-AB)_2$] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with $a=7.6397(6){\AA}$, $b=16.8761(18){\AA}$, $c=17.7713(19){\AA}$, ${\alpha}=90^{\circ}$, ${\beta}=98.9570(10)^{\circ}$, ${\gamma}=90^{\circ}$, $V=2.2633(4)nm^3$, Z = 4, F(000) = 1064, S = 1.058, $Dc=1.520g{\cdot}cm^{-3}$, $R_1=0.0412$, $wR_2=0.0948$, ${\mu}=1.128mm^{-1}$. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.

• Structural Engineering and Mechanics
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• 제62권3호
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• pp.345-355
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• 2017

The aim of the present study is to develop an elemental approach based on the differential quadrature method for free vibration analysis of cracked thin plate structures. For this purpose, the equations of motion are established using the classical plate theory. The well-known Generalized Differential Quadrature Method (GDQM) is utilized to discretize the governing equations on each computational subdomain or element. In this method, the differential terms of a quantity field at a specific computational point should be expressed in a series form of the related quantity at all other sampling points along the domain. However, the existence of any geometric discontinuity, such as a crack, in a computational domain causes some problems in the calculation of differential terms. In order to resolve this problem, the multi-block or elemental strategy is implemented to divide such geometry into several subdomains. By constructing the appropriate continuity conditions at each interface between adjacent elements and a crack tip, the whole discretized governing equations of the structure can be established. Therefore, the free vibration analysis of a cracked thin plate will be provided via the achieved eigenvalue problem. The obtained results show a good agreement in comparison with those found by finite element method.

• Bulletin of the Korean Chemical Society
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• 제35권12호
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• pp.3495-3501
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• 2014

A novel crystal, the mono-protonated metformin acetate (1), was obtained and characterized by elemental analysis, IR spectroscopy and X-ray crystallography. It was found that one of the imino group in the metformin cation was protonated along with the proton transfer from the secondary amino group to the other imino group. Its crystal structure was then compared with the previously reported diprotonated metformin oxalate (2). The difference between them is that the mono-protonated metformin cations can be linked by hydrogen bonding to form dimers while the diprotonated metformin cations cannot. Both of them are stabilized by intermolecular hydrogen bonds to assemble a 3-D supermolecular structure. The four potential tautomer of the mono-protonated metformin cation (tautomers 1a, 1b, 1c and 1d) were optimized and their single point energies were calculated by Density Functional Theory (DFT) B3LYP method based on the Polarized Continuum Model (PCM) in water, which shows that the most likely existed tautomer in human cells is the same in the crystal structure. Based on the optimized structure, their Wiberg bond orders, Natural Population Analysis (NPA) atomic charges, molecular electrostatic potential (MEP) maps were calculated to analyze their electronic structures, which were then compared with the corresponding values of the diprotonated metformin cation (cation 2) and the neutral metformin (compound 3). Finally, the possible tautomeric mechanism of the mono-protonated metformin cation was discussed based on the observed phenomena.

• 조형예술학연구
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• 제3권
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• pp.178-224
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• 2001

This thesis aims to suggest the notion of the sublime as one of the common elements of contemporary plastic arts, as a new key for the reading of our visual environment. The concept of sublimity has been one of important categories in traditional aesthetics since the eighteenth century; beyond the domain of this tradition, however, it is rigorously investigated in sociology, literary criticism, visual art theory and post-structuralist philosophy, especially the investigation of post-modern conditions by Jean-Fran cois Lyotard. Jean-Fran cois Lyotard defines sublimity as the elemental feature of the late twentieth century visual arts based on post-structuralism and suggests the feeling of the sublime as dominant sensibility in post-modern society. According to Lyotard, the sublime is a contradictory feeling of pleasure mixed with suffering as in the theory of experimental avant-gardes; the post-modern sublimity is the feeling of suffering or agony when we feel in confronting the new and the unknown. The investigation of the sublime based on Lyotard's perspectives, therefore, is meaningful in decoding contemporary visual arts. This investigation, therefore, mainly deals with the post-modern concept of the sublime and contemporary visual arts viewed in the sublime.