本文从大学英语教学和 Blended L earning的产生、发展等多视角透视其概念内涵 ;在计算机及网络技术已经全面且实质性地应用于我国英语教学的今天 ,正确地把握 Blended L earning的本质将有助于教育技术在英语教学改革中发挥越来越重要...本文从大学英语教学和 Blended L earning的产生、发展等多视角透视其概念内涵 ;在计算机及网络技术已经全面且实质性地应用于我国英语教学的今天 ,正确地把握 Blended L earning的本质将有助于教育技术在英语教学改革中发挥越来越重要的作用。展开更多
The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model unce...The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model uncertain, is much more complex than conventional nero-fin control. A novel nonlinear backstepping control approach is proposed to design the blended autopilot. Missile model is reformed to a new one by state reconstruction technique so that it is easy to be handled by the backstepping method. Then a Lyapunov function is chosen to avoid oscillation caused in normal backstepping way when control parameters are mismatched. In distribution of both inputs, optimal energy logic is proposed. In addition, a fuzzy cerebellar model articulation controller （FCMAC） neural network is used to guarantee controller robustness to uncertainties. Finally, simulation results demonstrate the efficiency and advantages of the proposed method.展开更多
In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform...In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform the high-dimensional and correlative influencing factors data to low-dimensional principal component subspace. Well-trained SVM was used to extract influencing factors as input to predict blended coal's property. Then experiments were made by using the real data, and the results were compared with weighted averaging method (WAM) and BP neural network. The results show that PCA-SVM has higher prediction accuracy in the condition of few data, thus the hybrid model is of great use in the domain of power coal blending.展开更多
本文介绍了 Blending L earning(或 Blended L earning)的新含义 ,指出这一新含义的提出和被广泛认同 ,表明国际教育技术界的教育思想观念正在经历又一场深刻的变革 ,也是教育技术理论进一步发展的标志。作者还从对建构主义理论的反思...本文介绍了 Blending L earning(或 Blended L earning)的新含义 ,指出这一新含义的提出和被广泛认同 ,表明国际教育技术界的教育思想观念正在经历又一场深刻的变革 ,也是教育技术理论进一步发展的标志。作者还从对建构主义理论的反思、对信息技术教育应用认识的深化 。展开更多
本文介绍了 Blending L earning(或 Blended L earning)的新含义 ,指出这一新含义的提出和被广泛认同 ,表明国际教育技术界的教育思想观念正在经历又一场深刻的变革 ,也是教育技术理论进一步发展的标志。作者还从对建构主义理论的反思...本文介绍了 Blending L earning(或 Blended L earning)的新含义 ,指出这一新含义的提出和被广泛认同 ,表明国际教育技术界的教育思想观念正在经历又一场深刻的变革 ,也是教育技术理论进一步发展的标志。作者还从对建构主义理论的反思、对信息技术教育应用认识的深化 。展开更多
The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like...The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like structure with state-dependent coef- ficient （SDC） matrices. Based on the linear-like structure, a θ-D feedback controller is designed to steer the missile to track refer- ence acceleration commands. A sufficient condition that ensures the asymptotic stability of the tracking system is given based on Lyapunov＇s theorem. Numerical results show that the proposed autopilot achieves good tracking performance and the closed-loop tracking system is asymptotically stable.展开更多
基金the China Aviation Science Foundation (03D12004)
文摘The advanced missile uses blended control of nero-fin and reaction-jet to improve missile maneuverability. The blended control design, which is multi-inputs and multi-outputs （MIMO）, severe nonlinear, and model uncertain, is much more complex than conventional nero-fin control. A novel nonlinear backstepping control approach is proposed to design the blended autopilot. Missile model is reformed to a new one by state reconstruction technique so that it is easy to be handled by the backstepping method. Then a Lyapunov function is chosen to avoid oscillation caused in normal backstepping way when control parameters are mismatched. In distribution of both inputs, optimal energy logic is proposed. In addition, a fuzzy cerebellar model articulation controller （FCMAC） neural network is used to guarantee controller robustness to uncertainties. Finally, simulation results demonstrate the efficiency and advantages of the proposed method.
基金Project(50579101) supported by the National Natural Science Foundation of China
文摘In order to predict blended coal's property accurately, a new kind of hybrid prediction model based on principal component analysis (PCA) and support vector machine (SVM) was established. PCA was used to transform the high-dimensional and correlative influencing factors data to low-dimensional principal component subspace. Well-trained SVM was used to extract influencing factors as input to predict blended coal's property. Then experiments were made by using the real data, and the results were compared with weighted averaging method (WAM) and BP neural network. The results show that PCA-SVM has higher prediction accuracy in the condition of few data, thus the hybrid model is of great use in the domain of power coal blending.
基金supported by the National Natural Science Foundation of China(61174203)the Aeronautical Science Foundation of China(20110177002)
文摘The missile autopilot for an interceptor with tail fins and pulse thrusters is designed via the θ-D approach. The nonlin- ear dynamic model of the pitch and yaw motion of the missile is transformed into a linear-like structure with state-dependent coef- ficient （SDC） matrices. Based on the linear-like structure, a θ-D feedback controller is designed to steer the missile to track refer- ence acceleration commands. A sufficient condition that ensures the asymptotic stability of the tracking system is given based on Lyapunov＇s theorem. Numerical results show that the proposed autopilot achieves good tracking performance and the closed-loop tracking system is asymptotically stable.
