In a complex environment resulted from the economic and technological changes, and the emergence of the uncertainty cases, the entrepreneurial thought knows a development in the determinants of entrepreneurial spirit,...In a complex environment resulted from the economic and technological changes, and the emergence of the uncertainty cases, the entrepreneurial thought knows a development in the determinants of entrepreneurial spirit, that has become a mechanism and a dynamic of the competitivety of international economies, starting by the construction of investment projects whether individual or collective, which are based on innovation and the use of technology as factors that have the ability to give business competitiveness and increase its economic efficiency, also that is through the creation of job opportunities and reaching the economic development. This research aims to study the effect of the religious dimension and the dimensions of entrepreneurial behavior on the entrepreneurial intention among youth who are interested in realizing entrepreneurial projects. The partial least squares approach （PLS） has been used in this study and it results that the religious dimension influences positively the entrepreneurial intention.展开更多
This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided...This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.展开更多
An alternating least squares approach is developed in this paper to identify the exponential recovery dy- namic load model of wide-area power systems. The nonlinear optimization problem is decomposed to two linear lea...An alternating least squares approach is developed in this paper to identify the exponential recovery dy- namic load model of wide-area power systems. The nonlinear optimization problem is decomposed to two linear least squares problems, and solved in an alternating way. Then, a new algorithm for numerical derivative calculation using dis- crete Fourier transform is proposed to attenuate the effect of noises in the process of parameter estimation. Based on the estimated dynamic load characteristics, the application on voltage stability is analyzed. Finally, numerical and laboratory examples are conducted to demonstrate the effectiveness of the orooosed methods.展开更多
文摘In a complex environment resulted from the economic and technological changes, and the emergence of the uncertainty cases, the entrepreneurial thought knows a development in the determinants of entrepreneurial spirit, that has become a mechanism and a dynamic of the competitivety of international economies, starting by the construction of investment projects whether individual or collective, which are based on innovation and the use of technology as factors that have the ability to give business competitiveness and increase its economic efficiency, also that is through the creation of job opportunities and reaching the economic development. This research aims to study the effect of the religious dimension and the dimensions of entrepreneurial behavior on the entrepreneurial intention among youth who are interested in realizing entrepreneurial projects. The partial least squares approach （PLS） has been used in this study and it results that the religious dimension influences positively the entrepreneurial intention.
文摘This paper focuses on the indicators of soil and litter health, disturbance, and landscape heterogeneity as a tool for prediction of ecosystem sustainability in the northern forests of Iran. The study area was divided into spatial homogenous sites using slope, aspect, and soil humidity classes. Then a range of sites along the disturbance gradient was selected for sampling. Chemical and physical indicators of soil and litter health were measured at random points within these sites. Structural equation modeling(SEM) was applied to link six constructs of landscape heterogeneity, three constructs of disturbance(harvest, livestock, and human accessibility), and soil and litter health. The results showed that with decreasing accessibility, the total N and organic matter content of soil increased and effective bulk density decreased. Harvesting activities increased soil organic matter. Therefore, it is concluded that disturbances through harvesting and accessibility inversely affect the soil health. Unexpectedly, it was found that the litter total C and C:N ratio improved with an increase in the harvest and accessibility disturbances, whereas litter bulk density decreased. Investigation of tree composition revealed that in the climax communities, which are normally affected more by harvesting activities, some species like Fagus orientalis Lipsky with low decomposition rate are dominant. The research results showed that changes in disturbance intensity are reflected in litter and soil indicators, whereas the SEM indicated that landscape heterogeneity has a moderator effect on the disturbance to both litter and soil paths.
基金supported by the National Natural Science Foundation of China(Nos.61202340,61125301)
文摘An alternating least squares approach is developed in this paper to identify the exponential recovery dy- namic load model of wide-area power systems. The nonlinear optimization problem is decomposed to two linear least squares problems, and solved in an alternating way. Then, a new algorithm for numerical derivative calculation using dis- crete Fourier transform is proposed to attenuate the effect of noises in the process of parameter estimation. Based on the estimated dynamic load characteristics, the application on voltage stability is analyzed. Finally, numerical and laboratory examples are conducted to demonstrate the effectiveness of the orooosed methods.
