Environmentalists'approach to sustainable development is essentially different fromeconomists'in that environmental sustainability is set as a condition in biophysical limits. Furthermorethere exist alternativ...Environmentalists'approach to sustainable development is essentially different fromeconomists'in that environmental sustainability is set as a condition in biophysical limits. Furthermorethere exist alternative strategies for achieving environmental sustainability. This paper intends to assessand compare these alternatives in the context of environmental resource stock and economic outcomes , sothat the circumstances in which a particular strategy is preferred.would be suggested.展开更多
Feedbacks given by teachers is possibly a common instruction in second language writing classes, to help students makeprogress in writing. At one time, feedback was almost entirely at a superficial level--identifying ...Feedbacks given by teachers is possibly a common instruction in second language writing classes, to help students makeprogress in writing. At one time, feedback was almost entirely at a superficial level--identifying the grammatical errors and givingthe correct form. However, recently, this type of feedback has begun to be challenged by some researchers(eg.,Krashen, 1984, Trus-cott, 1996),who argue that teachers should be more concerned with the content of essay instead of grammatical errors. This essaywill discuss some research surrounding feedback to students' writing and will try to find the answer to the question whether the er-ror corrective feedback should be abandoned. In order to find the answer, the essay will elaborate on two parts: some literary reviewabout the issue and some suggested solutions to the issue.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Environmentalists'approach to sustainable development is essentially different fromeconomists'in that environmental sustainability is set as a condition in biophysical limits. Furthermorethere exist alternative strategies for achieving environmental sustainability. This paper intends to assessand compare these alternatives in the context of environmental resource stock and economic outcomes , sothat the circumstances in which a particular strategy is preferred.would be suggested.
文摘Feedbacks given by teachers is possibly a common instruction in second language writing classes, to help students makeprogress in writing. At one time, feedback was almost entirely at a superficial level--identifying the grammatical errors and givingthe correct form. However, recently, this type of feedback has begun to be challenged by some researchers(eg.,Krashen, 1984, Trus-cott, 1996),who argue that teachers should be more concerned with the content of essay instead of grammatical errors. This essaywill discuss some research surrounding feedback to students' writing and will try to find the answer to the question whether the er-ror corrective feedback should be abandoned. In order to find the answer, the essay will elaborate on two parts: some literary reviewabout the issue and some suggested solutions to the issue.
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.
