Adaptive neural design frame for uncertain stochastic nonlinear non-lower triangular pure-feedback systems with input constraint

This paper dedicates to dealing with the adaptive neural design problem for uncertain stochastic nonlinear systems with non-lower triangular pure-feedback form and input constraint. On the basis of the mean-value theorem, the pure-feedback structure is first transformed into the desired affine structure, and then the well-known backstepping technology is applied to construct the actual input signal of the controller. Although the considered system has a fairly complex structure, a new adaptive neural tracking controller design frame is established via the flexible application of radial basis function (RBF) neural networks’ (NNs’) structural characteristics. The proposed design frame guarantees the control objective of this paper can be achieved. Finally, a simulation example is given to further illustrate the availability of the proposed control scheme.     

培养高素质生源选拔优秀设计人才

工业设计在经济建设中发挥着重要作用.设计师应具有较高的文化素质和艺术修养,应是全面发展的高素质人才.而我国的设计教育在招生方式和招生标准方面还存在许多问题,致使生源素质不高,不能选拔出高素质人才.所以必须对传统的招生方式进行改革,发展工业设计要从培养生源和选拔人才抓起.     

A mixed-methods analysis of achievement disparities in Guatemalan primary schools

Although most Guatemalan rural students currently have access to primary school, there are large differences in the levels of learning that take place among different populations and in different contexts. This paper uses multiple data and methods to examine the interrelated factors underlying achievement disparities in Guatemalan primary schools. The research suggests that strong levels of disadvantage connected to attending schools in poor rural communities are connected to systematic differences in the way school quality is supported in different contexts. There are inadequate resources, capacity, and authority to monitor and enforce fundamental educational issues, especially in marginal communities.     

性格与交际法教学

交际法自80年代以来已发展成为世界规模的外语教学理论和方法。学习者的性格对交际法的成功实施有着很大的影响。因此,对于不同性格的学习者,我们在实施交际法时应注意采取相应的对策。     

Partial reinforcement effects on discrimination learning

Rats were trained on a series of reversals of a successive discrimination in which the percentage of S+ trials ending in food was varied. Changes in the discrimination index occurred more slowly with 50% reinforcement than with 100% reinforcement when the number of training trials was equated across conditions, but were approximately invariant when the conditions were equated with respect to the number of obtained reinforcements. Presentation of free reinforcement during the intertrial intervals reduced the overall rate of discrimination acquisition, but left this invariance unaffected. Invariance in reinforcements necessary to attain acquisition also occurred when different discriminations correlated with different percentages of reinforcement were intermixed within experimental sessions. The failure of the invariance effect to be disrupted by either manipulation suggests that previous accounts of the invariance effect in terms of “comparator” models of conditioning (e.g., Gibbon & Balsam, 1981) are inadequate.