In this paper, we present an investigation on the tracking performances of feedback control as a function of reference signals. We use multi-objective optimal designs of feedback controls as a fair basis for comparing...In this paper, we present an investigation on the tracking performances of feedback control as a function of reference signals. We use multi-objective optimal designs of feedback controls as a fair basis for comparing different control designs, and examine step, ramp, and periodic signals at various frequencies. Through comparing the tracking performances of controls designed with different reference signals,we find that the controls designed with ramp signals perform better in tracking step and ramp references than those designed with step signals. To track periodic signals, we find that the controls designed with periodic signals at the same frequency generally provide the best performance, and those designed with step and ramp signals perform comparably.展开更多
This paper is about the designing and description of an adult spoken English course. Teaching Chinese adult learners spoken English often poses a great difficulty because of their heterogeneous English level. Yet with...This paper is about the designing and description of an adult spoken English course. Teaching Chinese adult learners spoken English often poses a great difficulty because of their heterogeneous English level. Yet with careful planning and research it can be a successful story, too. First, the objective of the course must be set. Second, an interview must be carried out to find out how wide the range of English ability is . Third, a textbook that can fulfil the objective and meet the English level of the learners must be selected. Fourth, a teaching method that will help the learners work from controlled expression to guided expression and eventually to free expression must be developed. Last, but not the least, teacher feedback is of vital importance in teaching adult learners. and in providing such feedback reformulation has proved to be effective.展开更多
基金supported by the National Natural Science Foundation of China (Nos.11172197,11332008 and 11572215)a Grant from the University of California Institute for Mexico and the United States (UC MEXUS)the Consejo Nacional de Cienciay Tecnología de México (CONACYT) through the project "Hybridizing Set Oriented Methods and Evolutionary Strategies to Obtain Fast and Reliable Multi-objective Optimization Algorithms"
文摘In this paper, we present an investigation on the tracking performances of feedback control as a function of reference signals. We use multi-objective optimal designs of feedback controls as a fair basis for comparing different control designs, and examine step, ramp, and periodic signals at various frequencies. Through comparing the tracking performances of controls designed with different reference signals,we find that the controls designed with ramp signals perform better in tracking step and ramp references than those designed with step signals. To track periodic signals, we find that the controls designed with periodic signals at the same frequency generally provide the best performance, and those designed with step and ramp signals perform comparably.
文摘This paper is about the designing and description of an adult spoken English course. Teaching Chinese adult learners spoken English often poses a great difficulty because of their heterogeneous English level. Yet with careful planning and research it can be a successful story, too. First, the objective of the course must be set. Second, an interview must be carried out to find out how wide the range of English ability is . Third, a textbook that can fulfil the objective and meet the English level of the learners must be selected. Fourth, a teaching method that will help the learners work from controlled expression to guided expression and eventually to free expression must be developed. Last, but not the least, teacher feedback is of vital importance in teaching adult learners. and in providing such feedback reformulation has proved to be effective.
