一类带不确定输入动态非线性系统的鲁棒H∞控制

研究一类带不确定输入动态非线性系统的H∞控制问题.在输入动态存在的条件下, 利用反传设计方法构造了鲁棒状态反馈控制器,使得闭环系统在零初始状态下从干扰到输出的 L2增益任意小,同时在干扰输入恒为零时闭环系统是全局渐近稳定的.     

用Visual C++实现PLC实时监控

用VisualC + +和MFC开发了上位机和PLC的通讯系统 ,给出了系统的通讯原理和软件设计方法。运行结果表明 ,此方法简单、稳定、实用性强     

基于拟牛顿算法的空间机械臂姿态优化控制

为了研究机械臂系统在自由漂浮情况下的姿态控制问题,采用输入参数化的方法将连续量的最优控制问题转化为离散量的最优控制问题.利用拟牛顿算法确定最优控制输入信号,可以得到非完整系统运动的优化轨迹.通过数值仿真,表明对于类似的问题该算法是可行的.     

执行器饱和单输入线性系统的分析和设计

若线性系统可被某状态线性反馈全局渐近镇定 ,饱和介入反馈后 (具有反馈的 )系统稳定性或得以保持 ,或降为区域渐近稳定 .本文作者就这一问题给出简洁判据 ,且对后者计算其不变吸引 (超 )椭球 ;在此基础上用叠代法求取使椭球尽量大的反馈增益 ;最后用算例说明方法的有效性 .     

虚拟输入队列与队列管理算法的公平性

提出了具有不同接入带宽用户共享上行链路时的公平性问题——基于用户的公平性，根据队列管理算法(如早期随机检测和队尾丢弃等)在这种应用场合的公平性缺陷中引入了虚拟输入队列的概念——在路由器的上行输出接口上为每一个输入接口维护一个逻辑队列，以逻辑队列为主体应用队列管理算法。对虚拟输入队列的结构和实现进行了详细描述，并给出了针对虚拟输入队列的调度算法。仿真结果表明，在队列管理策略上引入虚拟输入队列，不仅能够达到原有的拥塞控制效果，解决基于流的公平性问题，同时能够提供较好的基于用户的公平性。     

职工住宅小区高速多媒体网络的开发

随着信息技术和计算机网络技术等高科技的迅猛突破与广泛普及,将会有越来越多的家庭通过Internet/In tranet来获取信息和资讯.向社区内广大居民家庭提供综合信息的资讯服务,将是社区网必须建立的服务设施.     

西门子变频器在给料控制系统中的应用

介绍了西门子变频器在给料控制系统中的应用，并详细介绍了变频系统的构成、特点和调试。     

Using non-keyboard input devices: interviews with users in the workplace

A study of 45 non-keyboard input device (NKID) users was undertaken at nine organisations to investigate the extent, pattern and method of NKID usage, workstation configurations, postures adopted and musculoskeletal symptoms. A number of methods were used: work activity diaries, interviews, observations and postural assessments. A range of NKID were seen including the mouse, touchscreen, joystick, trackball, and tablet and pen; however, the mouse was the most commonly used device. Use of an input device varied from 2% to 100% of the working day. Workers undertook common tasks using a variety of methods (e.g. pull down menus, icons, device buttons). Users reported problems associated with the use of some devices, e.g. poor maintenance, lack of device responsiveness. Musculoskeletal pain and discomfort (e.g. stiffness and discomfort in the hands and wrist) was reported by 45% (n=19) of mouse users and 16% (n=5) of other NKID users. Workstation configurations varied and in some cases constrained the position of the input device, resulting in users having to work with the device at some distance away from the body. Despite the existence of regulations and guidance, this paper indicates that there are still many problems related to NKID use at computer workstations.

Relevance to industry

The reliance of many software applications on NKID (e.g. mouse, trackball, touchpad, joystick, touchscreen) necessitates the investigation of their use in the workplace. Whilst the performance aspects of NKID (e.g. speed) have been well researched, the possible implications for user health have received little attention in the UK.     

Neuronal Signal Transduction Aided by Noise at Threshold and at Saturation

A classical model of neuronal signal transmission describing the presence of both a threshold and a saturation in the neuron response is considered. This model is used to analyze the transduction by the neuron of various types of information-carrying input signals in the presence of noise. Improvement by noise of the performance via stochastic resonance is established for transmission in both the threshold and the saturation regimes. Stochastic resonance at saturation is a novel form, expressing that the distortion experienced by large input signals transmitted at saturation, can be reduced by addition of noise.     

微机型变压器差动保护误动作原因分析与对策

通过对一起微机型变压器差动保护误动作的原因分析,揭示了变压器的暂态饱和对差动保护的影响。提出了利用制动电流的二次谐波比进行闭锁的新方法,该方法可提高微机型变压器差动保护的可靠性。