Methods Of Moment Research Articles

A Comparative Analysis of Effects of Education on Sub-Saharan Africa’s Economic Growth

This study aims to analyze and to compare the effects of various levels of education on the economic growth of some selected countries in Sub-Saharan Africa (SSA) between 1980 and 2015.It is hypothesized in the study that various levels of education have significant positive impacts on the economic growth of some selected sub-Saharan Africa countries over the stated period. Fixed effect Least Square Dummy Variable (LSDV) and a robust version of System Generalized Methods of Moment (SYSGMM) are adopted as model estimating techniques. Results from the LSDV model indicate increasing positive impacts of various levels of education on the economic growth of the thirty selected SSA countries. This trend of significance is corrected in the dynamic model, but with negative effects on the lower levels of education on growth while higher education output which negatively impacted on growth is reversed. The study systematically compares the effects of education on growth when higher education is included and when it is excluded both at the enrolment and output level in the regression model. We found different results at each instance for the various levels. Therefore, the major conclusion of this study is that higher education human capital at the output level appears to be the most significant of all the levels of education. However, this advantage enjoyed by higher education could have been as a result of cumulative effects from other levels of education over time. We, therefore, conclude that higher education should be supported with strong education policy implementation, as this could have a positive impact on SSA economic growth.

Productivity effects of higher education human capital in selected countries of Sub-Saharan Africa

This study aimed to analyse the productivity effects of higher education enrolment (HEE), higher education output (HEO) and the associated productivity gap (GP) on selected countries in Sub-Saharan Africa (SSA) over the period between 1981 and 2014. It was hypothesized in the study that HEE and HEO had statistically significant positive impact on productivity in the selected sub-Saharan Africa countries over the stated period. Fixed effect Least Square Dummy Variable (LSDV) and a robust version of System Generalized Methods of Moment (SYSGMM) were adopted as model estimating techniques. Results from the LSDV model indicated that HEE had no statistically significant positive impact on productivity growth in the twenty-one SSA countries. This non-significance was corrected in the dynamic model, but with negative effects on the growth rate of total factor productivity (TFP). The study further compared the worldwide technological frontier with those of the SSA countries under investigation and discovered that countries like Gabon, Mauritius and Swaziland ranked high, while Burundi needs to improve on its productivity determinants. The major conclusion of this study is therefore that higher education human capital should be supported with strong policy implementation, as this can have a positive impact on productivity growth.

Banks’ capital regulation and risk: Does bank vary in size? Empirical evidence from Bangladesh

This paper primarily examines both causality effect of banks’ capital regulation and risk-taking behavior based on generalized methods of moment (GMM) for a dynamic unbalanced panel observation of 32 commercial banks in Bangladesh over the period 2000–2014. The empirical findings of this study suggest that capital regulation has a significant effect on risk-taking behavior, and excessive risks impede the growth of capital ratio as well as the stability. Moreover, from bank-level data, size does not uniformly affect the quantity of capital and risk. Large banks have poor capital ratio and higher inclination to risk than small size counterpart. Small size banks are well managed in capital ratio and risk-taking that glitter their stability through the periods. Besides these effects, corporate governance notably influenced banks to reduce credit risk and enhance stability. Finally, this paper provides some implications for the think tanks and stakeholders of the country.

An empirical test of the Balassa-Samuelson hypothesis: Evidence from eight middle-income countries in Africa

The paper tests the validity of the Balassa-Samuelson hypothesis (BSH) using the within-effects and the dynamic panel generalised methods of moment (GMM) techniques for a panel of eight middle-income African countries over the period 1960–2009. We selected these countries because they exhibited a mixture of relative productivity growth and real exchange rate misalignment that fits the characterization of the BSH well. The results strongly support the BSH for this group of countries. The results are valid even after we controlled for potentially omitted variables and endogeneity. The implication is that as these countries become more productive, their currencies appreciate in real terms.

Institutions and economic growth in Africa: Evidence from panel estimation

There is growing emphasis on the role of institutions on explaining Africa’s economic growth ahead of the traditional factors such as capital accumulation. However, it is not clear which of the institutions and governance indicators namely control of corruption, government effectiveness, political stability, regulatory quality, rule of law and voice and accountability matter most. This paper empirically examines the impact of institutions on economic growth in Africa. The paper uses a sample of 48 countries for the1996-2016 period. The overall number of observations is 912. The paper applied generalized methods of moment (GMM), fixed effects (FE) and random effects (RE) models. However, due to the fact that GMM is well suited to deal with potential endogeneity problems in the model, inferential statistics of this paper are drawn from GMM regression results. Results of the FE and RE regressions are presented in appendix. Empirical results show that institutions really matter for Africa’s economic growth. Among the institutional quality indicators political stability appears to be the most significant factor in explaining real GDP per capita growth in Africa. However, it is worth noting that, the quality of institutions alone may not be sufficient. Along with institutions, the paper reveals that structural factors such as liberalization of trade, fixed capital formation, labour force and foreign direct investment have a significant effect on Africa’s economic growth. The implication is that, a policy mix with the aim of improving the quality of institutions as well as reducing trade restrictions, enhancing both domestic and foreign investment and improving the quality of labour force would enhance economic growth in Africa.

The Causality Direction of the Stock Market–Growth Nexus: Application of GMM Dynamic Panel Data and the Panel Ganger Non-causality Tests

This study is an attempt to model the linkages between stock market development and economic growth in developed and emerging markets. The causality direction between stock market development and economic growth has also been examined in order to provide solid policy implications. Mainly, the relationship and direction of causality between stock market development and economic growth were tested using dynamic panel data analysis based on the Generalised Methods of Moment (GMM) and panel Granger non-causality, respectively. Additionally, panel unit root tests were also applied to check the stationary of the selected variables to avoid misleading results. The study focuses on 20 countries, both developed and emerging markets, and data were collected over the period 1990–2014 mainly from World Bank data series. Dynamic panel data analysis confirms that there is a statistically significant relationship between stock market development and economic growth in both developed and emerging markets. Further, the study emphasises that only the finance-led growth hypothesis is valid for emerging markets while developed markets support bidirectional causality between stock market development and economic growth, reflecting the existence of both the finance-led growth hypothesis and the growth-led finance hypothesis. Hence, it is crucial to formulate appropriate policies to shift unproductively allocated funds towards stock markets to meet long-term capital requirements to encourage higher economic growth. JEL Classification: C230, C220, G100, E010

Analysis of Retrospective Time to First Pregnancy Data in Uttar Pradesh under Various Dimensions

The present study deals with the estimation of the mean value of fecundability by fitting a theoretical distribution from the observed distribution of first conception of the women, who did not use any contraceptive method before their first conception. It is assumed that fecundability is fixed for a given couple, but across couples it varies according to a specified distribution. Under the classical approach, methods of moment and maximum likelihood are used while for Bayesian approach, empirical Bayes method used. A real data analysis from the third National Family Health Survey (NFHS-III, 2005-06) is analyzed as an application of model for various age at marriage groups of women. Finally, a simulation study is performed to access the performance of the several of methods used in this paper.Journal of Institute of Science and Technology, 2015, 20(1): 51-58

Quality, quantity and financial sustainability of microfinance: Does resource allocation matter?

Resource allocation is significant for a firm or business to attain its objective(s). In the case of informal lending institutions like microfinance, allocation of resources to attain financial sustainability and providing financial services to the poor community is an interesting area for exploration. Thus, this study endeavors to establish a relationship between microfinance resources (labor and capital) with its quality (depth), quantity (breadth) and financial sustainability. We used the system-generalized methods of moment with a panel dataset of 176 microfinance institutions (MFIs) between 2007 and 2012 in Bangladesh. The study finds that higher capital asset ratio (as a proxy of real capital investment) and number of employees had negative and positive impacts on quality, quantity and financial sustainability of microfinance institutions respectively. Furthermore, we have also estimated that higher capital asset ratio increases administrative cost of MFIs. These findings produce strong policy guidelines for the microfinance sector in Bangladesh, particularly for management of the MFIs. Individual MFIs should take precautionary measures before they shift their resources, mostly to capital goods instead of using labor in their operation.

Longitudinal-lateral-torsional integrated modeling based on a beam model for skin-stiffened structure

Tension-compression, bending and torsional stiffness of skin-stiffened cylindrical shell are systematically investigated, in which the differences are studied by the equivalence methods of area and moment of inertia. As to the equivalence method of area, the rationality that bending stiffness of skin-stiffened cylindrical shell is calculated and the reason why the torsional stiffness is multiplied by a mending coefficient are analyzed. The approach has been proposed to represent longitudinal-lateral-torsional dynamic model through NASTRAN. Based on that, FEM model of strap-on launch vehicle has been built, validated by test. This research has directive significance for coupling analysis and dynamics research of strap-on launch vehicle.

Firm, Country and Macroeconomic Determinants of Capital Structure: Evidence from Turkish Banking Sector

This study explores the significance of firm-specific, country, and macroeconomic factors in explaining variation in leverage using a sample of banks from Turkish banking sector. The analysis is based on quarterly firm-level data from Turkish banking sector in 2002–2012. We aims to contribute to the empirical capital structure literature in the following ways. Our first contribution comes from assessing the importance of firm-specific factors, country-level factors and industrial factors for capital structure decisions in Turkish banking sector. Second, we employ appropriate and advanced dynamic panel data estimators, Blundell and Bond’s (1998) generalized methods of moment’s estimators (GMM System). We find that leverage is significantly and positively associated with average industry leverage, firm size and GDP growth. We find also that leverage is significantly and negatively associated with tangibility, profitability, inflation and financial risk. The regression results for leverage are both theoretically and empirically plausible for banks in Turkey. Moreover, tangibility, profitability and GDP growth are consistent with the predictions of the pecking order theory, while firm size is consistent with the predictions of the trade-off theory. Our findings suggest that the capital structures of financial and non-financial firms are ultimately determined by the same drivers.

Statistical Inferences and Applications of the Half Exponential Power Distribution

We investigate the statistical inferences and applications of the half exponential power distribution for the first time. The proposed model defined on the nonnegative reals extends the half normal distribution and is more flexible. The characterizations and properties involving moments and some measures based on moments of this distribution are derived. The inference aspects using methods of moment and maximum likelihood are presented. We also study the performance of the estimators using the Monte Carlo simulation. Finally, we illustrate it with two real applications.

Factors Influencing Rope Force of Recoil Starter

Rope force of recoil starter is an important design parameter for starting safety. This paper analyzes the starting resistance torque of an internal combustion engine, and then proposes the appropriate calculation methods of friction resistance moment, compression resistance moment and inertia resistance moment. Taking several types of internal combustion engines for example, this paper analyzes the main factors influencing rope force, and then draws the conclusion that displacement and ambient temperature are the key to the rope force. The work provides the basis for the design and inspection of recoil starter.

Assessment of bio-activity using the methods of inertia moment and absolute value of the differences

In this paper, a numerical analysis of the time history of speckle pattern (THSP) has been carried out by means of a co-occurrence matrix (COM) that assembles the intensity distributions of speckle pattern of the specimen with regard to time. Experiments have been performed to implement inertia moment (IM) and absolute value of the differences (AVD) methods on the biospeckle COMs. In the present work, we have used three different Indian fruits namely pear, apple and tomato for the study of bio-activities using above methods for the first time. The variation of IM and AVD with frequency is found to increase for all the fruits but apple has relatively higher rate of increase of IM and AVDs in comparison to pear and tomato. In addition, the value IM for the fruits is found to decrease with the aging of the sample but apple has relatively lower rate of decrease of IM in comparison to pear and tomato.

The appropriate model geometrical characteristics suitable for use in an Eiffel type subsonic boundary layer wind tunnel

The study of parameters selection of model sizing appropriate for use in an Eiffel type subsonic boundary layer wind tunnel was investigated. Using a prototype-model dimension scale of 1:300 on a 72 m, 20 storey prototype building with ratio 1:2:6; a width of 43.33, 83.33 mm breadth and 240 mm height was produced as physical model. The result of the application of methods of global modular ratio and area moment for parameters selection shows that the moments of inertia obtained from the two methods only differ by 2.33%. The proposed hollow rectangular configuration recommended as walls for the physical model are 10.5 and 20.2 mm thick along the width and breadth, respectively. The assemblage of the models was rigidly bounded together by using a set of G-clamping devices and special adhesives such as epoxy resin and liquid glue. The base of the physical model was mounted on flat steel plate which serves as an infinitely rigid foundation resting on the polystyrene that represents the soil conditions which was assumed to behave as elastic base. At the end, the model was rigidly fastened to the wind tunnel using solenoid wires. The original data generated for the dimensions were intrinsically linear and they were linearized using a natural logarithm model. Ordinary least square regression analysis conducted on the result show that y = 1.94 + 0.433x. The analysis of variance (ANOVA) is significant at P = 0.001 but the corresponding standard deviation, correlation coefficients and student’s T are S = 0.1561, R - Sq = 93.9% and T = 9.23, respectively. All these statistically confirm that there are no serious trends to show that the proposed models are inappropriate. Key words: Model sizing, strouhal number, Bernoulli universal constant, wind tunnels, model scaling, multi-storey, building, aerodynamics loadings.

Competition in MENA countries banking markets

This study examines the banking power in a number of highly concentrated banking industries. In particular, this paper tests the competitive conditions in the banking industries of six Middle Eastern and North African (MENA) countries for the period from 1998 to 2007. Using the new industrial organisation literature methodology, our results reveal that the banking market structure can be characterised as monopolistic competition. The result of this study is necessary for policy makers in MENA region. For them this is a signal to review their policy of interference and involvement in changes in the market structure of the banking markets and to be cautious of the process of consolidation and increasing concentration. Our results are rigorous under a variety of specification controlling for bank size, risk and a number of estimation techniques including static and dynamic data analysis (Fixed or Random effects and the Generalised Methods of Moment).

NLL과 GMM을 중심으로 한 확산모형 추정법 비교

현대금융공학에 있어서 확산모형은 중요한 역할을 담당하고 있다. 다양한 형태의 확산모형이 제안되어왔고 현실에 응용되어 왔다. 확산모형을 이용하여 금융자료를 분석하기 위하여는 확산모형의 모수를 추정하는 것이 필수불가결한 단계이다. 이들 모수에 대한 다양한 추정방법들이 제안되어 왔고, 많은 연구에서 이러한 추정방법들이 갖는 성질에 대하여 연구되어져왔다. 이 연구에서는 그 적용방법이 단순하여 가장 자주 사용되는 것으로 알려진, 오일러 근사법과 신국소근사법(NLL) 그리고 일반화 적률법(GMM)과 같은 세 가지 추정방법들에 대한 통계적 성질을 검토하게 될 것이다. 모의실험연구를 통하여 오일러근사법이나 NLL방법이 GMM 방법에 비하여 훨씬 좋은 성질을 가지고 있음을 보이게 된다. 특히 GMM은 적용방법이 단순할 뿐만 아니라 강건성(robustness)이라는 좋은 성질을 가지고 있는 것으로 알려져 있어서 많은 연구에서 매우 자주 사용되는 추정방법이다. 그러나 본 연구에서 확인해 본 바와 같이 GMM은 그 사용법이 오히려 더욱 단순한 NLL이나 오일러방법에 비하여 열등한 통계적 성질을 보여주고 있었다. 특히나 확산계수에 추정모수가 포함된 경우에 GMM은 매우 좋지 못한 성질을 보이게 된다. Since the research of Black and Scholes (1973), modeling methods using diffusion processes have performed principal roles in financial engineering. In modern financial theories, various types of diffusion processes were suggested and applied in real situations. An estimation of the model parameters is an indispensible step to analyze financial data using diffusion process models. Many estimation methods were suggested and their properties were investigated. This paper reviews the statistical properties of the, Euler approximation method, New Local Linearization(NLL) method, and Generalized Methods of Moment(GMM) that are known as the most practical methods. From the simulation study, we found the NLL and Euler methods performed better than GMM. GMM is frequently used to estimate the parameters because of its simplicity; however this paper shows the performance of GMM is poorer than the Euler approximation method or the NLL method that are even simpler than GMM. This paper shows the performance of the GMM is extremely poor especially when the parameters in diffusion coefficient are to be estimated.

Resonance response of a single-degree-of-freedom nonlinear vibro-impact system to a narrow-band random parametric excitation

The resonant response of a single-degree-of-freedom nonlinear vibro-impact oscillator with a one-sided barrier to a narrow-band random parametric excitation is investigated. The narrow-band random excitation used here is a bounded random noise. The analysis is based on a special Zhuravlev transformation, which reduces the system to one without impacts, thereby permitting the applications of random averaging over “fast" variables. The averaged equations are solved exactly and an algebraic equation of the amplitude of the response is obtained for the case without random disorder. The methods of linearization and moment are used to obtain the formula of the mean-square amplitude approximately for the case with random disorder. The effects of damping, detuning, restitution factor, nonlinear intensity, frequency and magnitude of random excitations are analysed. The theoretical analyses are verified by numerical results. Theoretical analyses and numerical simulations show that the peak response amplitudes will reduce at large damping or large nonlinear intensity and will increase with large amplitude or frequency of the random excitations. The phenomenon of stochastic jump is observed, that is, the steady-state response of the system will jump from a trivial solution to a large non-trivial one when the amplitude of the random excitation exceeds some threshold value, or will jump from a large non-trivial solution to a trivial one when the intensity of the random disorder of the random excitation exceeds some threshold value.

Development of SOM combustion model for Reynolds-averaged and large-eddy simulation of turbulent combustion and its validation by DNS

The derivation and closure methods of the second-order moment (SOM) combustion model are proposed. The application of this model to Reynolds averaged (RANS) and large-eddy simulation (LES) of turbulent swirling diffusion combustion, jet diffusion combustion, and bluff-body stabilized premixed combustion is summarized. It is indicated that the SOM model is much better than the eddy-beak-up (EBU) and presumed PDF models widely used in commercial software and engineering. The SOM modeling results are close to those obtained using the most accurate but much more complex PDF equation model. Moreover, it can save much more computation time than the PDF equation model. Finally, the SOM model is validated by the direct numerical simulation (DNS) of turbulent reacting channel flows.

A multi-form modelling approach to the dynamics and control of drum granulation processes

Drum granulation processes are represented by a set of mass transfer, solid transport, as well as population balance equations. The population balance is mathematically described by partial differential–integral equations. The overall granulation model is highly non-linear, large-scale with multiple coordinates and uncertain parameters, leading to tremendous difficulties for optimisation and control. In our previous work, a two-level control strategy is proposed, which consists of an upper level optimal control for the determination of optimal set-points, and a lower level non-linear model predictive control (NMPC) for the simultaneous computations of uncertain parameters and control variables. However, long computing times and insufficient measurement data prevent industrial applications. In this paper, strategies are developed to improve the applicability of the multi-level, model predictive control scheme (ML-MPC) using the multi-form modelling approach. In the multi-form modelling approach, the granulation plants are represented by a variety of model forms for different end-uses. These include: (1) the distributed parameter population balance model (DP-PBM), (2) the lumped parameter population balance model (LP-PBM), (3) matrix representation with off-line computed matrix elements, (4) local linear models, (5) reduced order models using balanced truncating and methods of moment. It can be shown through dynamic simulations that significant computing time reductions can be achieved with properly selected model forms. Since both open-loop optimal control and closed loop MPC rely on iterative dynamic optimisation, overall computing time reduction makes on-line applications possible. Furthermore, the development of local linear models allows the applications of well-established linear system theory and techniques to process control, parameter identification and model order reduction. The demonstrated advantages of the proposed multi-form modelling approach imply a big step forward towards the industrial applications of model-based control for granulation processes.

Single integral expression of impedance between arbitrary placed bent rectangle dipoles in moment method using surface elements

AbstractOne of the analysis methods of moment for antennas and scatterers composed of perfect conductors is the subdomain Galerkin's method, in which the surface currents are expanded piecewisely and the expansion and the weighting functions are the same. In comparison with the point matching method, the subdomain Galerkin's method can obtain accurate results with fewer segment partitions. However, it is necessary to perform fourfold integrations in the calculations of the impedance matrix elements. In the present paper, it is shown that the fourfold integrations of the impedance matrix elements between arbitrarily placed bent rectangular dipole segments can be reduced to single integral expressions. The validity of the proposed method is verified by comparison with the numerical results of fourfold integrations. © 2006 Wiley Periodicals, Inc. Electron Comm Jpn Pt 1, 89(6): 11–22, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecja.20276