Search results

1 – 10 of over 26000
Book part
Publication date: 2 June 2008

Eric W. Bond and Robert A. Driskill

We extend the Jones (1971) analysis of the effects of distortions in 2×2 trade models to the case of a two-sector dynamic general equilibrium model of a small open economy…

Abstract

We extend the Jones (1971) analysis of the effects of distortions in 2×2 trade models to the case of a two-sector dynamic general equilibrium model of a small open economy with capital accumulation. We do a comparative steady state analysis for the effect of policy changes on factor prices and the capital stock, and examine the dynamics of the system in the neighborhood of the steady state. We also show that the system will have multiple equilibria when value and physical factor intensity rankings of the sectors do not agree.

Details

Contemporary and Emerging Issues in Trade Theory and Policy
Type: Book
ISBN: 978-1-84950-541-3

Keywords

Article
Publication date: 2 May 2017

Guillaume Caron, Thomas Henneron, Francis Piriou and Jean-Claude Mipo

The purpose of this study is to determine the steady state of an electromagnetic structure using the finite element method (FEM) without calculation of the transient state

Abstract

Purpose

The purpose of this study is to determine the steady state of an electromagnetic structure using the finite element method (FEM) without calculation of the transient state. The proposed method permits to reduce the computation time if the transient state is important.

Design/methodology/approach

In the case of coupling magnetic and electric circuit equations to obtain the steady state with periodic conditions, an approach can be to discretise the time with periodic conditions and to solve the equation system. Unfortunately, the computation time can be prohibitive. In this paper, the authors proposed to use the waveform relaxation method associated with the Newton method to accelerate the convergence.

Findings

The obtained results show that the proposed approach is efficient if the transient state is important. On the contrary, if the transient state is very low, it is preferable to use the classical approach, namely, the time-stepping FEM.

Research limitations/implications

The main limitation of the proposed approach is the necessity to evaluate or to know the time constant and consequently the duration of the transient state. Moreover the method requires some important memory resources.

Practical/implications

In the context of the use of the time-stepping FEM, one of the problems is the computation time which can be important to obtain the steady state. The proposed method permits avoidance of this difficulty and directly gives the steady state.

Social/implications

The proposed approach will permit to model and study the electromagnetic systems in the steady state, and particularly the transformers. Because of the gain in computing time, the use of optimisation techniques will be facilitated.

Originality/value

The novelty of this study is the proposal of the waveform relaxation–Newton method to directly obtain the steady state when applied to the three-phase transformer.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Abstract

Details

Functional Structure Inference
Type: Book
ISBN: 978-0-44453-061-5

Article
Publication date: 2 May 2017

Tadeusz Sobczyk and Michał Radzik

The purpose of this study is to identify a novel methodology for direct calculation of steady-state periodic solutions for electrical circuits described by nonlinear…

Abstract

Purpose

The purpose of this study is to identify a novel methodology for direct calculation of steady-state periodic solutions for electrical circuits described by nonlinear differential equations, in the time domain.

Design/methodology/approach

An iterative algorithm was created to determine periodic steady-state solutions for circuits with nonlinear elements in a chosen set of time instants.

Findings

This study found a novel differential operator for periodic functions and its application in the steady-state analysis.

Research limitations/implications

This approach can be extended to the determination of two- or multi-periodic solutions of nonlinear dynamic systems.

Practical implications

The complexity of the steady-state analysis can be reduced in comparison with the frequency-domain approach.

Originality/value

This study identified novel difference equations for direct steady-state analysis of nonlinear electrical circuits.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 36 no. 3
Type: Research Article
ISSN: 0332-1649

Keywords

Article
Publication date: 1 January 2013

Ebrahim Babaei and Hamed Mashinchi Mahery

The purpose of this paper is to propose a new method for mathematical modeling of the buck dc‐dc converter in discontinuous conduction mode (DCM). By using the presented…

Abstract

Purpose

The purpose of this paper is to propose a new method for mathematical modeling of the buck dc‐dc converter in discontinuous conduction mode (DCM). By using the presented modeling method, the analysis of the transient and the steady states of the buck dc‐dc converter can be performed.

Design/methodology/approach

The proposed method is based on the two Laplace and Z transforms. In the proposed method, at first, the equations of the inductor current and the capacitor voltage are obtained as the power switch is on and off. Then by using the Laplace and Z transforms, the obtained equations are solved and the relations of the inductor current and the output voltage are obtained. In the proposed method, the Laplace transform is used for determining of the general relations of the inductor current and the output voltage. Also the Z‐transform is used as a tool for determining the initial values of the inductor current and the output voltage.

Findings

The transient and the steady state response of the dc‐dc converter is analyzed by the proposed method. By using the Z‐transform, the transient response of the converter and the effect of the elements of the converter on the time constant of the transient response are investigated. In addition, the effect of the elements of the converter and the load resistance on the electrical parameters of the converter such as the output voltage ripple and the inductor current ripple are investigated.

Originality/value

The proposed method in this paper is a suitable method for mathematical modeling of dc‐dc converters. The acernote of this method is that it can be used in both transient and steady state response, analysis of the dc‐dc converters. By using the final value theorem of the Z‐transform, the steady state response of the converter is investigated. Also by using this transform, the time constants of the transient response of the converter are determined. Finally, the results of the theoretical analysis are compared with the results of simulation in PSCAD/EMTDC and also the experimental results to prove the validity of the presented subjects.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 32 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

Book part
Publication date: 14 July 2008

Matthias Doepke and Dirk Krueger

We investigate the positive and normative consequences of child-labor restrictions for economic aggregates and welfare. We argue that even though the laissez-faire outcome…

Abstract

We investigate the positive and normative consequences of child-labor restrictions for economic aggregates and welfare. We argue that even though the laissez-faire outcome may be inefficient, there are usually better policies to cure these inefficiencies than the imposition of a child-labor ban. Given this finding, we investigate the potential political-economic reasons behind the emergence and persistence of child-labor legislation. Our investigation is based on a structural dynamic general equilibrium model that provides a coherent and uniform framework for our analysis.

Details

Frontiers of Family Economics
Type: Book
ISBN: 978-1-84950-542-0

Article
Publication date: 1 December 1998

Rosa Capolupo

This paper reviews one of the crucial issues in the recent growth literature concerning the hypothesis of cross country convergence of levels and growth rates of income…

2611

Abstract

This paper reviews one of the crucial issues in the recent growth literature concerning the hypothesis of cross country convergence of levels and growth rates of income per capita implied by the neo‐classical growth model, both in the Solow‐Swan and Rampsey‐Cass‐Koopmans versions. The alternative endogenous growth models, consistent with permanent income inequality, are considered. Convergence to a common income level versus divergence is discussed from a theoretical point of view. Then, empirical tests of the convergence property are presented. What emerges is that Barro type regressions and their findings about “conditional” convergence are questionable and cannot be used to give a definitive response on this issue.

Details

Journal of Economic Studies, vol. 25 no. 6
Type: Research Article
ISSN: 0144-3585

Keywords

Article
Publication date: 16 July 2018

Ziyan Yang

The most recent and prestigious scientific research shows that nitrogen leaching caused by over-used nitrogen fertilizer rapidly acidifies all soil types in China…

Abstract

Purpose

The most recent and prestigious scientific research shows that nitrogen leaching caused by over-used nitrogen fertilizer rapidly acidifies all soil types in China, revolutionizing the basic understanding of the mechanism of soil acidification. The purpose of this paper is to study the impact of nitrogen on soil acidity over the long run, which is the shadow price of nitrogen.

Design/methodology/approach

In a discrete dynamic programming model, this paper compares the nitrogen application and soil pH between optimal nitrogen control that takes the shadow price of nitrogen into consideration and myopic nitrogen control that ignores that shadow price. Using a five-year panel experimental data on a rapeseed-rice rotation, this paper simulates and numerically solves the dynamic model.

Findings

Both theoretically and empirically, this paper shows that the over-use of nitrogen and the decline in soil pH are explained by ignorance of the shadow price of nitrogen. Compared with optimal nitrogen control, myopic nitrogen control applies more nitrogen in total, resulting in lower soil pH. In addition, over-use in the first season contributes to soil acidification and the carry-over effects mitigate that problem.

Originality/value

This paper enriches the literature by extending the study of the environmental impact of nitrogen leaching to its impact on the long-term loss in agricultural production, providing a new theoretical framework in which to study soil acidification rather than conventionally treating soil acidification as a secondary consequence of acid rain, and showing the possibility of using nitrogen control to mitigate soil acidification when lime applications are not feasible due to socio-economic constraints.

Details

China Agricultural Economic Review, vol. 11 no. 3
Type: Research Article
ISSN: 1756-137X

Keywords

Article
Publication date: 1 August 2002

Duangpun Kritchanchai and Bart MacCarthy

Identifies the need for a formal procedure to generate a reference state when conducting qualitative simulation studies. A procedure for generating a reference state is…

Abstract

Identifies the need for a formal procedure to generate a reference state when conducting qualitative simulation studies. A procedure for generating a reference state is presented and justified. The procedure considers output performance indicators, steady state conditions, system capacity and model validity. Its application is illustrated using a simulation model for an order fulfillment process. The calibration process is necessarily iterative and subjective to some degree and in general does not generate a unique reference state. The impact of using different reference states in a simulation experiment is illustrated. In general the results are consistent when interpreted qualitatively in terms of direction, trend and order of magnitude. The approach is most applicable for qualitative simulation studies where comparative performance is being investigated and where precise numerical estimation is not required. However the procedure is also applicable to the study of real systems where data is not available.

Details

Industrial Management & Data Systems, vol. 102 no. 6
Type: Research Article
ISSN: 0263-5577

Keywords

1 – 10 of over 26000