基于自适应遗传算法的模拟电路的电路级综合

利用准精确惩罚函数法构造出价格函数,并且采用自适应遗传算法,进行电路级综合,以获得全局最优解。实验结果表明:利用本方法可以快速设计出满足性能指标的CMOS运算放大器。     

Robust adaptive controller design for a class of nonlinear systems with unknown high frequency gains

INTRODUCTIONMany researchers have devoted their energy to the development of nonlinear system with unknown control directions during the past few years. The class of nonlinear system has been developed greatly since Mudgett and Morse (1985) relaxed the assumption that the unknown multiplicative terms are not only sign-invariant but also have known signs. A method called correction vector approach was proposed in (Lozano et al., 1990) and has been applied to design adaptive controller of …     

一类非线性时滞系统的鲁棒自适应控制

针对一类含有非线性参数的非线性时滞系统．利用参数分离技术和后推方法,提出了一种自适应状态反馈控制方案,保证闭环系统的所有信号全局一致有界。通过构造Lyapunov—Krasoviskii泛函证明了系统的状态能收敛到零的一个小邻域内。     

An embedded packet train and adaptive FEC scheme for effective video adaptation over wireless broadband networks

INTRODUCTION With the emergence of wireless technology, various multimedia services, e.g., audio and/or video, are reaching us today through portable devices any- time, anywhere and even more increasingly accessi- ble in the near future. High quality video streaming over wireless IP is one of the most attractive applica- tions by ongoing deployment of wireless local area network (WLAN) hotspots and even powerful Wi- MAX mobile coverage. However, the present Internet is not providing a…     

自助借还书系统中的多书侦测研究

对所借图书进行多书侦测研究,可尽量减少自助式借还书过程中的违规操作,设计一种工作于可见光波段的多书侦测系统。该系统利用摄像装置跟踪被借还图书,提取并分析图书侧面图以判断是否存在违规操作。系统能够自适应地进行图书侧面的识别和提取,具有良好的侦测借还书过程中违规行为的能力。     

Profile of South African secondary-school teachers’ teaching quality: evaluation of teaching practices using an observation instrument

The need for quality teaching is reflected in the poor performance of students in international tests. Teachers’ practices and contextual factors could contribute to substandard quality of teaching in South Africa. Several studies indicate that successful learning is largely dependent on the teachers’ practices in class. The focus of the present research was to profile the effective teaching practices of 424 secondary-school teachers in the Gauteng Province, South Africa. Teachers were observed by trained observers using a valid and reliable observation instrument measuring six domains of effective teaching practices. Results showed that teachers find it difficult to differentiate in class and to activate learning. Additionally, teachers with more than 15 years of teaching experience scored lower than teachers with less experience, in all six teaching domains. Presumably, experienced teachers may lack motivation and/or insufficient training in implementing interactive and differentiated teaching methods that are needed for effective teaching practices.     

Adaptively selecting biology questions generated from a semantic network

The paper describes a biology tutoring system with adaptive question selection. Questions were selected for presentation to the student based on their utilities, which were estimated from the chance that the student’s competence would increase if the questions were asked. Competence was represented by the probability of mastery of a set of biology knowledge components. Tasks were represented and selected based on which knowledge components they addressed. Unlike earlier work, where the knowledge components and their relationships to the questions were defined by domain experts, this project demonstrated that the knowledge components, questions and their relationships could all be generated from a semantic network. An experiment found that students using our adaptive question selection had reliably larger learning gains than students who received questions in a mal-adaptive order.     

基于遗传算法的电梯群控研究

针对电梯群控系统的特点,设计出一种更适合的梯群控制的遗传算法.本算法中采用了整数编码和可进行种群竞争的双种群机制,设计了以候梯时间、乘梯时间、系统能耗为群控目标的多目标适应度函数.并在选择操作中引入个体最优选择策略,在交叉操作中构造了与遗传代的数目、预交叉个体本身特点相结合的交叉方式,在变异操作中应用了两点对换和位点变异相结合的变异方法,并设计了从最优解集合中选择最优解的评价函数.经过模拟仿真,运行实验结果表明了此方案的可行性和优越性.     

Numerical issues in backstepping control: Sensitivity and parameter tuning

The backstepping-based adaptive tuning functions design is a control-scheme for uncertain systems that ensures reasonably good stability and performance properties of the closed loop. The complexity of the controller makes inevitable the use of digital computers to perform the calculation of the control signal. This paper addresses the issue of the numerical sensitivity of this control scheme. It is shown that while the increase of the design parameters may be desirable to achieve a good transient performance, it harms the control signal as this increase introduces large high-frequency components due to the numerical errors. The presented results suggest that it is necessary a certain compromise between the choice of the design parameters and the numerical precision of the tools involved in the control design. This compromise can be quantified by explicit expressions.     

基于中值背景模型的运动目标自适应检测方法

针对复杂交通场景中运动车辆检测方法存在的局限性,本文提出了一种基于中值模型和自适应阈值的运动检测算法。利用自适应阈值对差分图像的三个颜色通道进行二值化处理,实现了运动目标的精确检测,采用中值更新策略实现背景图像的实时更新。实验结果表明,算法可以从复杂交通场景图像序列中有效地检测出运动目标,且算法计算量小,具有良好的鲁棒性与实时性。