• 제목/요약/키워드: equilibrium analysis

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부분균형분석과 장기균형: 산업완결균형 (Partial Equilibrium Analysis and Long-run Equilibrium: Full Industry Equilibrium)

  • 박만섭
    • 사회경제평론
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    • 제31권3호
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    • pp.131-163
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    • 2018
  • 경제의 장기균형은 경제에 존재하는 모든 기업들이 '초과이윤 = 0'의 조건을 충족하는 상태이다. '다른 모든 변수들이 불변'(ceteris paribus)이라는 가정에 근거한 전통적 부분균형분석은 장기균형과 논리적으로 상충한다. '산업완결균형'(full industry equilibrium)은 전통적인 부분균형분석보다 포괄적인 부분균형의 틀 속에서 개별 산업의 장기균형을 다룬다. 산업완결균형에 대한 비교정태분석은 개별 기업/산업에 대하여 기존의 부분균형분석이 도출하는 결과들이 성립하지 않을 수 있음을 보인다. 본 논문은 산업완결균형의 배경과 의의를 소개한다. 이 과정에서 산업완결균형 분석과 1960-70년대의 자본논쟁이 갖는 유사점과 상이점을 논의하고, 산업완결균형 분석의 비판적 의의와 건설적 의의를 밝힌다.

KSR-III 로켓 노즐의 열화학적 성능해석 (Thermochemical Performance Analysis of KSR-III Rocket Nozzle)

  • 최정열;최환석;김영목
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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    • pp.90-98
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    • 2001
  • Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed, those were coupled with the methods of computational fluid dynamics code. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis. The approaches were used for the performance prediction of KSR-III Rocket, and compared with the theoretical results from NASA CEA (Chemical Equilibrium with Applications) code.

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케이블 돔 구조물 설계를 위한 수치해석 방법 (A Numerical Analysis Approach for Design of Cable Dome Structures)

  • 김재열;장동우
    • 한국공간구조학회:학술대회논문집
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    • 한국공간구조학회 2008년도 춘계 학술발표회 논문집
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    • pp.89-94
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    • 2008
  • This paper deals with the method of self-equilibrium stress mode analysis of cable dome structures. From the point of view of analysis, cable dome structure is a kind of unstable truss structure which is stabilized by means of introduction of prestressing. The prestress must be introduced according to a specific proportion among different structural member and it is determined by an analysis called self-equilibrium stress mode analysis. The mathematical equation involved in the self-equilibrium stress mode analysis is a system of linear equations which can be solved numerically by adopting the concept of Moore-Penrose generalized inverse. The calculation of the generalized inverse is carried out by rank factorization method. This method involves a parameter called epsilon which plays a critical role in self-equilibrium stress mode analysis. It is thus of interest to investigate the range of epsilon which produces consistent solution during the analysis of self-equilibrium stress mode.

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고속전철 시스템의 정적평형 및 선형진동 해석 (Static equilibrium and linear vibration analysis of a high speed electric train system)

  • 김종인;유홍희;황요하
    • 한국철도학회논문집
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    • 제2권4호
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    • pp.1-8
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    • 1999
  • A formulation to perform static equilibrium and linear vibration analysis is presented in this paper. The formulation employs minimum number of equations of motion which are derived by using a partial velocity matrix. The static equilibrium analysis is performed first, then the linear vibration analysis is performed at the static equilibrium position. By using the formulation presented in this paper, static equilibrium and linear vibration analysis of a high speed electric train system are performed. A single bogie system, a power car vehicle, and a train system which consists of five vehicles are analyzed, respectively. Natural frequencies and a few lowest mode shapes of the two are identified in this paper.

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로켓 노즐 유동의 열/화학적 특징 및 해석 기법 (Thermochemcial Characteristics of Rocket Nozzle Flow and Methods of Analysis)

  • 최정열
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2001년도 춘계 학술대회논문집
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    • pp.144-148
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    • 2001
  • Characteristics of high temperature rocket nozzle flow is discussed along with the aspects of computational analysis. Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were discussed those were coupled with the methods of computational fluid dynamics. A chemical equilibrium code developed for the analysis of general hydrocarbon fuel was coupled with three approaches of nozzle flow analysis, and a test was made for a bell nozzle at typical operation condition. As a results, the characteristics of the approaches were discussed in aspects of rocket performance, thermal analysis and computational efficiency.

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Numerical Study of Chemical Performance of 30 tonf -class LRE Nozzle of KARI

  • Kang, Ki-Ha;Lee, Dae-Sung;Cho, Deok-Rae;Choi, H.S.;Choi, J.Y.
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년 영문 학술대회
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    • pp.448-451
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    • 2008
  • Three methods of nozzle flow analysis, frozen-equilibrium, shifting-equilibrium and non-equilibrium approaches, were used to rocket nozzle flow, those were coupled with the methods of computational fluid dynamics code. For a design of high temperature rocket nozzle, chemical equilibrium analysis which shares the same numerical characteristics with frozen flow analysis can be an efficient design tool for predicting maximum thermodynamic performance of the nozzle. Frozen fluid analysis presents the minimum performance of the nozzle because of no consideration for the energy recovery. On the other hand, the case of chemical-equilibrium analysis is able to forecast the maximum performance of the nozzle due to consideration for the energy recovery that is produced for the fast reaction velocity compared with velocity of moving fluid. In this study, using the chemical equilibrium flow analysis code that is combined the modified frozen-equilibrium and the chemical-equilibrium. In order to understand the thermochemical characteristic components and the accompanying energy recovery, shifting-equilibrium flow analysis was carried out for the 30 $ton_f$-class KARI liquid rocket engine nozzle together with frozen flow. The performance evaluation based on the 30 $ton_f$-class KARI LRE nozzle flow analyses will provide an understanding of the thermochemical process in the nozzle and performances of nozzle.

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조속기의 동적 평형위치 해석 (Analysis of Dynamic Equilibrium Configuration of Speed Governor)

  • 강주석
    • 한국산학기술학회논문지
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    • 제14권10호
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    • pp.4733-4738
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    • 2013
  • 본 연구에서는 구속조건을 가진 기계계의 동적 평형위치를 다물체 동역학 해석방법을 이용하여 계산하였다. 다물체계에서 얻어지는 시간 구속조건을 가진 구속조건식과 동역학식으로부터 독립좌표계로 이루어진 동적평형식을 유도하였다. 동적 평형식은 구속조건식과 함께 비선형 대수방정식의 형태로서 Newton-Raphson 방법을 이용하여 수치해를 구하였다. 제안된 동적 평형 계산 방법을 조속기에 적용하여 동적 평형위치를 구하였다. 해석결과는 상용 프로그램의 동역학해석을 통한 평형위치의 결과와 비교하여 타당성을 검증하였다. 조속기의 회전 각속도에 대한 평형위치를 계산하고 설계 파라미터에 대한 평형위치의 영향을 분석하였다.

인도페놀법을 이용한 수용액 중 암모니아 정량에 관한 연구 : 평형법, 반응속도법, 흐름주입분석법의 비교와 평가 (Determination of Aqueous Ammonia with Indophenol Method : Comparision and Evaluation for the Reaction-Rate, Equilibrium and Flow-Injection Analysis Methods)

  • 정형근;김범식
    • 한국환경과학회지
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    • 제4권1호
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    • pp.91-103
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    • 1995
  • The reaction rate, equilibrium, and flow injection analysis methods were fundamentally evaluated for the determination of aqueous ammonia. The selected indophenol blue method was based on the formation of indophenol blue in which ammonium ion reacted with hypochlorite and phenol in alkaline solution. In the optimized reaction condition, the reaction followed 1st order reaction kinetics and the final product was stable. The absorbance measurements before and after the equilibrium were utilized for the reaction rate and equilibrium methods. The reaction rate methods, based on the relative analytical signals for the possibility of eliminating interferents, were shown to have good linear calibration curves but the detection limit and the calibration sensitivity were poorer than those in the equilibrium method. The detection limits were 32-49 pub and 24 pub for the reaction rate and equilibrium methods, respectively In the flow injection analysis, the absorbance was measured before the equilibrium reached and thus resulted in 30% reduction of calibration sensitivity. However, the detection limit was 11 ppb, indicating that the peak-to-peak noise for the blank was remarkably improved. Compared to the manual methods, the optimized experimental condition in a closed reaction system reduced the blank absorbance and the inclusion of ammonia from the atmosphere was prevented. In addition, highly reproducible mixing of sample and reagents and analytical data extracted from continuous recording showed excellent reproducibility.

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유체가 흐르는 곡선관의 진동 해석과 비선형 평형 방정식 (Vibration Analysis and Non-linear Equilibrium Equations of a Curved Pipe Conveying Fluid)

  • 정두한;정진태
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2005년도 춘계학술대회논문집
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    • pp.983-986
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    • 2005
  • Free vibration characteristics of a curved pipe conveying fluid is studied when the pipe is clamped at both ends. Using the perturbation method, the non-linear governing equations divided into two parts; the steady state non-linear equilibrium equations and the linearized equations of motion in the neighborhood of the equilibrium position. The natural frequencies are computed from the linearized equations of motion. In this study, the equilibrium positions are determined by two types of equations, i.e., (1) the non-linear equations, and (2) the equations obtained by neglecting the non-linear terms. The natural frequencies obtained from the non-linear equilibrium equations are compared to those obtained from the linearized equilibrium equations. From the results, as the fluid velocity increases, the equilibrium position should be determined from the nonlinear equations for the vibration analysis of the curved pipe conveying fluid.

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한계평형법과 개별요소법을 이용한 보은지역 암반사면 안전율 비교해석 (Comparison Analysis of Factor of Safety on Rock Slope in Boeun Region Using Limit Equilibrium Method and Distinct Element Method)

  • 이지수;유광호;박혁진;민경덕
    • 한국지반공학회:학술대회논문집
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    • 한국지반공학회 2002년도 봄 학술발표회 논문집
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    • pp.643-650
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    • 2002
  • The large planar failure has occurred in a rock cut slope of highway construction site in Boeun. This area is considered as unstable since the discontinuities whose orientations are similar to the orientation of the failure plane, are observed in many areas. Therefore, several analysis techniques such as SMR, stereographic analysis, limit equilibrium, numerical analysis, which are commonly used in rock slope stability analysis, are adopted in this area. In order to analyze the stress redistribution and nonlinear displacement caused by cut, which are not obtained in limit equilibrium method, the UDEC and shear strength reduction technique were used in this study Then the factors of safety evaluated by shear strength reduction technique and limit equilibrium were compared. In addition, the factor of safety under fully saturated slope condition was calculated and subsequently, the effect of the reinforcement was evaluated.

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