基于延时估计和漏桶算法的自适应多媒体同步控制

本文针对分组交换网中多媒体通信缺乏QoS的特性,在接收端利用RTP协议的时戳对网络延时进行动态地估计,进而根据漏桶算法,自适应调节和维持多媒体同步。仿真实验表明,这种同步控制机制能够适应各种不同的网络环境,效果良好。     

WDM网络中实时组播的分布式路由与波长分配算法

在WDM网络中,由于每条链路上可用波长是动态变化的,在考虑波长转换延迟时间的条件下,实现实时组播连接的路由与波长分配是十分困难的。该文提出了一种用于建立实时组播连接的分布式路由与波长分配算法。该算法将路由与波长分配统一进行,大大减少连接的建立时间。组播路由算法以Prim最小生成树算法和K-度宽度优先搜索方法为基础,生成一棵满足给定延迟时限的最小成本树。波长分配使用最少波长转换和负载平衡策略。     

广东110kV电网大面积停电问题的分析及解决方案

介绍了广东110kV电网大面积停电的情况，针对广东110kV系统接地方式，对110kV电网主变中性点放电间隙误动和保护动作配合时间失配的情况进行了详细的分析，提出了解决方案。     

有限次休假的M/G/1排队模型研究

研究了有限次休假的M／G／1排队模型中系统的稳态平衡条件，系统的队长，顾客的延误时间等排队指标。     

基于多带HMM和神经网络融合的语音识别方法的信道鲁棒性

对于基于HMM的语音识别系统,由于训练和测试环境(背景噪声。语音传输信道Microphone等)的失配将会造成识别性能的严重下降。根据人类的听觉感知机理,该文针对语音传输信道失配问题,提出了一种基于多带HMM的系统结构,有若干个子带系统和一个全频带子系统组成,并采用神经网络对个子系统的输出进行后端融合及判决。实验表明,这种方法可以有效地提高识别系统的信道鲁棒性。     

基于改进的BP网络误差修正的广义预测控制

该文利用预测误差的历史数据，基于改进的BP神经网络，对系统的建模误差进行预测。该网络采用了修正激励函数的BP算法，预测性能好，能够克服标准BP算法中Sigmoid函数的不足，加快了网络的学习速度。并将其与模型预测相结合构成广义预测控制算法，有效地克服了模型失配的影响，提高了控制的速度，同时引入控制增量增益，利用这个自由度来提高闭环的稳定鲁棒性。仿真结果表明了该算法的有效性。     

pH过程的模糊控制仿真研究

pH过程广泛存在于化工、生物工艺、污水处理、发电等工业过程中，对这一过程进行良好的控制有着十分重要的意义。由于pH过程是一个具有严重非线性及滞后性的被控对象，传统的PID控制难以达到理想的控制效果。本文使用模糊控制技术，设计采用了带有自调整因子的模糊控制器，不仅能较好地处理pH过程的严重非线性和滞后性，而且具有较强的鲁棒性和抗干扰能力。     

The effects of refractive index heterogeneity within kidney tissue on multiphoton fluorescence excitation microscopy

Although multiphoton fluorescence excitation microscopy has improved the depth at which useful fluorescence images can be collected in biological tissues, the reach of multiphoton fluorescence excitation microscopy is nonetheless limited by tissue scattering and spherical aberration. Scattering can be reduced in fixed samples by mounting in a medium whose refractive index closely matches that of the fixed material. Using optical 'clearing', the effects of refractive index heterogeneity on signal attenuation with depth are investigated. Quantitative measurements show that by mounting kidney tissue in a high refractive index medium, less than 50% of signal attenuates in 100 μm of depth.     

Observer design and stabilization for linear neutral delay systems

This paper focuses on the state observer design problem as well as the observer-based stabilization problem for linear neutral delay systems. The purpose of the former problem is to design an observer that guarantees the asymptotic stability of the estimation error dynamics. The existence condition for such an observer is established. The latter problem, which is the main problem studied in this paper, aims at designing an observer-based feedback controller, such that the closed-loop system is asymptotically stabilized. It is shown that the desired controller can be easily designed if there are solutions to several linear matrix inequalities. Finally, two simulation examples are given to demonstrate the validity and effectiveness of the proposed approach.     

Dynamic asymmetrical instability of elastic–plastic beams

Dynamic instability of elastic–plastic beam is investigated by employing a three-degree-of-freedom (3-DoF) beam model. Especially, asymmetrical instability induced by symmetrical load is discussed. The asymmetrical instability is considered as a second-order buckling mode. Four types of perturbations, i.e., geometrical misalignment, material property mismatch, unsymmetry of applied load and disturbance of boundary conditions, are introduced to activate the asymmetrical responses. The asymmetrical response is characterized by a modal participation factor α₂ which corresponds to an asymmetrical mode shape. Phase plane trajectories and Poincaré map are used to illustrate the chaotic characteristics of the beam response. Results show that if the perturbations are small enough, the perturbation type has negligible influence on the critical load for the occurrence of the asymmetrical instability, which implies that the asymmetrical instability is an intrinsic feature of the beam system. However, with the increase of the magnitude of the perturbations, the influence of the asymmetrical vibration is expanded to a large extension of loading parameter.