单级倒立摆建模及其控制方法设计

单级倒立摆控制是一个即复杂而又对准确性、快速性要求很高的非线性不稳定系统控制问题。单级倒立摆数学模型的建立对研究其稳定性具有指导作用。用拉格朗日功能平衡法建立了倒立摆的刚体动力学方程,采用了LQR法对其进行了控制设计,并且进行了MATLAB仿真,结果表明此方法均可以成功控制倒立摆,使其稳定并具有良好的鲁棒性。     

Neural basis for the genesis and control of digitalis arrhythmias

The author discussed the increase in the frequency of traumatic paralyses of the ocular muscles, and reported 6 cases of inferior oblique muscle paresis caused by local blunt or sharp traumas (haematoma, contusion, rupture, incarceration) and one case of traumatic Brownian pseudo-paralysis. The localisation of the injuries in 3 cases was on the inferior temporal part and in the other 3 cases on the superior part of the bulbar conjunctiva. Atypical horizontal deviation and characteristic vertical deviation, torsion and torticollis were observed in the majority of cases. One patient recovered spontaneously. 3 patients became asymptomatic after correction by prisms and one after recession of contralateral superior rectus muscle. The symptoms remained unchanged in the case of a "blow out" fracture (in spite of operation) and a Brown's syndrome (without treatment).     

Abdominoperineal resection following anterior resection

A series of 11 patients undergoing abdoninoperineal resection for "suture line recurrence" following anterior resection is presented. Five-year survival is 10%. Technically, the procedure is difficult and major problems are encountered, including large blood loss and ureteral complications. These patients had an inadequate distal margin of resection at the time of anterior resection. The survival of this group of patients underscores the importance of making the correct judgment about anterior or abdominoperineal resection at the time of the initial presentation of the patient. The phrase "suture line recurrence" is a misnomer; all of these patients had advanced pelvic malignancy. If the adequacy of the distal margin is questionable or a distal margin of 5 cm cannot be obtained safely at the time of anterior resection, abdominoperineal resection should be performed, as the opportunity for cure of a recurrence should this rule be compromised is limited.     

Automatic multiscale meshing through HRBF networks

A procedure for the real-time construction of three-dimensional (3-D) multiscale meshes from not evenly sampled 3-D points is described and discussed in this paper. The process is based on the connectionist model named hierarchical radial basis functions network (HRBF), which has been proved effective in the reconstruction of smooth surfaces from sparse noisy data points. The network goal is to achieve a uniform reconstruction error, equal to measurement error, by stacking noncomplete grids of Gaussians at decreasing scales. It is shown here how the HRBF properties can be used to develop a configuration algorithm, which produces a continuous surface in real time. In addition, the model is extended to automatically convert the continuous surface into a 3-D mesh according to an adequate error measure.     

Multiscale approximation with hierarchical radial basis functions networks

An approximating neural model, called hierarchical radial basis function (HRBF) network, is presented here. This is a self-organizing (by growing) multiscale version of a radial basis function (RBF) network. It is constituted of hierarchical layers, each containing a Gaussian grid at a decreasing scale. The grids are not completely filled, but units are inserted only where the local error is over threshold. This guarantees a uniform residual error and the allocation of more units with smaller scales where the data contain higher frequencies. Only local operations, which do not require any iteration on the data, are required; this allows to construct the network in quasi-real time. Through harmonic analysis, it is demonstrated that, although a HRBF cannot be reduced to a traditional wavelet-based multiresolution analysis (MRA), it does employ Riesz bases and enjoys asymptotic approximation properties for a very large class of functions. HRBF networks have been extensively applied to the reconstruction of three-dimensional (3-13) models from noisy range data. The results illustrate their power in denoising the original data, obtaining an effective multiscale reconstruction of better quality than that obtained by MRA.     

基于无线传感器网络的LEACH算法的改进

无线传感器网络是监控远程环境的工具之一.由于能量和存储空间的限制，其路由协议必须维持较小的路由信息并尽可能的减少能量消耗。该论文对经典的LEACH路由算法，提出了改进，改进后的算法基于无线电传输范围和簇成员数目形成簇，同时在转发阶段引进了CSMA/CD（载波监听多路访问/冲突检测）技术以减少冲突。最后用Matlab对LEACH算法和改进后的算法进行仿真，证实改进后的算法在能量消耗上比LEACH算法有了很大提高。     

网络在实验教学中的应用研究

本文分析了高校实验教学的现状以及实验课的课堂指导局限性,提出以网络辅助课堂指导,使其成为实验教学的一种补充,并分析了网络作为实验教学补充形式的优势和可能存在的问题。根据通信电路实验室的实验内容和发展规划,提出建设电子技术制作、开发和应用网站的实施方案。确定网站的发展分两个阶段,规划了每个阶段的任务。网站的系统平台充分利用了新技术的优势采用了Linux＋Apache＋PHP＋MySQL。为了搞好网络教学这种现代化的教学模式,笔者从教师、学生及网站等几个方面提出一些建议。     

基于互联网的电厂实时监控图形显示技术的应用

基于B/S体系结构开发Internet应用程序是当前的流行趋势.介绍了基于Internet的电厂实时监控图形显示技术的实现方法.采用目前工业监控环境中的图形动态交互技术,针对图形刷新闪烁现象这一关键问题提出了不同的解决方法.最后介绍了基于ActiveX控件技术的动态图形显示技术的应用实例.     

一种复合控制器在过热汽温中的应用研究

在电厂中,必须严格控制过热器出口蒸汽温度,蒸汽温度过高或过低,都将给安全生产带来不利影响。针对过热汽温被控对象的特点,充分利用模糊控制的动态特性好和PID调节能消除静态偏差的特性,设计了一种带自调整因子的模糊控制器,研究了Fuzzy-PID复合串级控制在电厂过热汽温控制系统中的应用,该复合控制器的切换采用一种简单的基于偏差量的模糊切换方法。仿真结果表明,Fuzzy-PID复合串级控制系统具有更好控制品质。     

表面裂纹深度检测的非接触光声检测技术研究

提出了一种基于激光超声宽带透射系数和的表征参数,实现了表面裂纹深度的定量检测。通过有限元仿真与实验测量方法,从时域和频域分析了激光产生的瑞利波与表面裂纹的相互作用机制,采用宽带透射系数和作为表征裂纹深度的物理参数,并建立了其与表面缺陷深度之间的拟合方程。结果表明,脉冲激光产生的瑞利波对金属表面裂纹深度变化十分敏感,所提出的计算方法可用于精确判断表面裂纹的深度。本文研究成果可为工件表面裂纹的非接触检测提供潜在应用。