基于场景自适应收敛非均匀性校正方法

收敛问题是基于场景非均匀性校正算法的一个共性问题,提出了一个能够自适应收敛的非均匀性校正算法,该算法的一个特点是只对非均匀性空间频率的高频部分进行处理,详细论述了该处理的优点,同时还提出了一个控制收敛速度的因子,使得算法的收敛速度根据场景的动态范围自动调整,这将很大程度的改善基于场景非均匀性校正算法收敛特性,最后通过实...     

光纤毫米波融合接入系统能量效率分析

随着高速移动通信需求的持续增长,“绿色通信”成为近期的研究热点.文章提出一种使用谐波生成毫米波的技术,同时结合ROF(光载无线)技术实现光纤/无线融合接入系统,该系统使用毫米波微微蜂窝接入网技术为室内移动终端提供接入服务.在此基础上,文章对上述系统进行了能量效率分析,通过与WLAN(无线局域网)接入方式的能量效率分析对...     

Service behavior modeling and service behavior convergence-based radio resource scheduling in wireless systems

With the development of wireless networks,the amount of multiple services increased sharply in recent years.High quality multiple services with low price are urgently needed especially in new generation mobile communication systems,e.g.,3G/LTE networks.It is important to enhance the availability of data service resources.Services have strong association which are used by clients with similar behavior habits in networks.Such feature results in service behavior convergence(SBC)and its utilization will enhance resource efficiency.This paper proposes two applications of service behavior:service prediction and a scheduling algorithm which enhances bandwidth efficiency.Convergence cells are classified according to SBC and hot-spot services are broadcasted separately in each convergence cell.It is demonstrated by stimulation that the bandwidth is saved 80% more than classical cellular system and nearly 20 % more than traditional broadcasting system.     

中国三网融合中的博弈及其影响

In January 2010, the State Council of China decided to speed up the convergence of the telecommunications network, cable network and Internet network. That means the government led practical exploration of the networks convergence. The convergence is related to the entities in the fields of telecommunications, broadcasting and the Internet industry. The authors apply the static game theory to analyze the games among the players in the fields of telecommunications and broadcasting, and point out that the games would strengthen the network infrastructures, promote the development of related industries, and profoundly influence and change the ways of thinking and social management in China. At last, the paper puts forward some policy recommendations.     

基于fal函数滤波的改进自抗扰技术的实现

自抗扰技术不但能观测系统的所有状态,还能观测系统模型不确定性及内外干扰,但该技术却忽略了测量噪声对系统观测的影响.基于解决测量噪声对观测系统精度的影响,提出了fal函数滤波方法,不仅能克服滤波后信号的幅值、相位与系统的真实输出差别较大的问题,而且具有快速收敛性和较高的滤波精度.仿真结果验证了该方法能够有效地滤除量测噪声...     

LLC变换器PSPICE仿真的收敛性及参数优化

针对LLC变换器使用PSPICE仿真器进行DC分析和瞬态分析时经常遇到不收敛的问题进行实验,列出了5种有效改进方法。比较了LLC谐振变换器3个参数优化设计的各种方案,提出并验证了运用PSPICE进行多参数优化设计的方法。实验表明,合理运用PSPICE,在谐振开关电源设计中常常会取得比其他方法(软件)更令人满意的效果。     

浅埋偏压隧道施工过程围岩应力变化规律研究

浅埋岩质公路隧道爆破开挖时,由于工程地质条件复杂,环境影响因素较多,施工安全是大家十分关注的重要问题。对密云火郎峪浅埋岩质公路隧道开挖施工过程进行了应力应变有限元计算分析和监控量测,结果对比分析可知,隧道开挖后拱顶存在明显的拱效应,拱脚处围岩压力集中,拱脚的安全直接影响到整个隧道的安全和施工;围岩压力、洞顶沉降和收敛监控量测表明,初衬支护后7d为构筑二次衬砌最理想的时机。正确的监测和计算分析可以预测和预知隧道在施工过程中可能发生的变形和结构所受的应力大小,指导设计和施工,提高隧道施工安全性。     

电机匝间短路故障信息融合诊断方法研究

针对目前应用的各种异步电机定子绕组匝间短路故障诊断方法都存在单一诊断技术问题,提出有选择地进行信息融合的理论,并给出了一个简单举例。结果表明,故障信息融合诊断方法可以大大提高电机匝间短路故障诊断的准确性和可靠性。     

Target Tracking Algorithm Using Finite-time Convergence Smooth Second-order Sliding Mode Controller for Mobile Robots

Target tracking control for wheeled mobile robot (WMR) need resolve the problems of kinematics model and tracking algorithm.High-order sliding mode control is a valid method used in the nonlinear tracking control system,which can eliminate the chattering of sliding mode control.Currently there lacks the research of robustness and uncertain factors for high-order sliding mode control.To address the fast convergence and robustness problems of tracking target,the tracking mathematical model of WMR and the target is derived.Based on the finite-time convergence theory and second order sliding mode method,a nonlinear tracking algorithm is designed which guarantees that WMR can catch the target in finite time.At the same time an observer is applied to substitute the uncertain acceleration of the target,then a smooth nonlinear tracking algorithm is proposed.Based on Lyapunov stability theory and finite-time convergence,a finite time convergent smooth second order sliding mode controller and a target tracking algorithm are designed by using second order sliding mode method.The simulation results verified that WMR can catch up the target quickly and reduce the control discontinuity of the velocity of WMR.     

基于ANSYS的对卡簧包紧力的接触分析

利用ANSYS对水管的接头进行接触分析,研究水管在工作状态下卡簧对其产生的接触应力,同时探讨了接触分析中接触模型对各参数的影响、有限元网格的划分和结果不收敛的原因,其中所述的分析方法对于装配体接触分析提供了参考。