基于连通概率感知的车联网资源优化技术研究

研究一种自由连通状态下基于车辆速度的多车道连通概率分析模型。该模型主要关注各个路段的连通概率,基于随机过程统计分析理论推导出多车道的道路连通概率。其次,针对单播或多播的端到端的消息分发场景,提出一种基于连通度概率感知的资源优化选择算法。该算法通过考虑车辆速度及方向特征,宏观层次上选择连通度概率高的路段作为数据包转发的路径;微观层次上针对每一路段进行基于邻居信息的多跳广播,快速地将数据包从路段入口传输到路段出口,提高数据分发效率。NS2仿真结果表明,提出的资源优化算法提高了分组转发的有效性,降低了车载网络的分组传输时延。     

基于业务触发式的跨层拓扑控制算法研究

对于无线网络技术,在满足一定的服务质量要求前提下,如何实现能量优化是无线网络设计必须面对的问题。现有的拓扑控制算法主要集中在如何提高网络的性能,较少考虑如何优化能量消耗。基于跨层的思想,提出了一种业务触发式的拓扑控制算法(STC),通过在网络中建立恰好承载当前业务的拓扑结构,使得信息包可以沿着能耗优化的路径向目的节点发送。通过仿真研究表明,该算法生成的网络拓扑结构在实现QoS参数和能量优化方面具有明显的优势。     

面向视频维护的拥塞感知自适应映射方法及其应用

针对生产制造系统中关键区域无线视频维护的传输复杂性和视频质量差等问题,提出了拥塞感知动态自适应双向映射算法。利用监控视频数据分层编码的特点,将视频帧与其他业务数据进行差分服务,同时根据实时网络负载状态引入拥塞感知机制,动态调用自适应前向和后向映射机制,既防止网络拥塞,充分利用网络资源,又有效提高了监控视频的传输质量。通过在不同网络负载条件下的实验表明,该算法不但能够显著改善监控视频传输质量,而且能够优化节点队列管理。     

基于贝叶斯决策的多网络切换算法

现有的垂直切换技术通常不支持多网络下切换.为此,提出了基于贝叶斯决策的改进算法.首先根据接入用户终端的信号强度、网络阻塞率和误码率以及不同用户业务对网络的实际需求建立多条件相关的切换概率分布,得出先验切换概率;然后利用贝叶斯垂直切换决策算法计算出后验概率;最后,根据后验概率的决策规则选出最优接入网络.仿真结果表明,该算法不仅有效地实现异构无线接入网之间的垂直切换,避免了不必要的切换,而且还能保持较高的网络平均负载,使用户获得更好的服务.     

一种基于多跳无线网络支持QoS的多信道MAC模型

提出了一种新的基于多跳无线网络MWN(Multi-hop wireless networks)支持端到端QoS的多信道媒介接入控制MAC模型。与以往的模型相比,该模型通过修改PCF轮寻机制,将只支持单跳网络的PCF功能扩展到多跳无线网络中,仿真结果表明:在无线多跳网络中,该MAC模型具有更高的数据吞吐率、更低的分组时延和分组丢失率,从而支持更高的数据服务质量QoS。     

基于改进粒子群的WSN多路径路由算法（英文）

为解决无线传感器网络(Wireless sensor network, WSN)节点能量受限、负载不均衡的问题,提出了一种邻域子空间合作的多路径负载均衡路由算法。算法将节点一跳邻域靠近基站区域内的节点划分在不同区域中,采用改进的粒子群优化算法,以最短距离和最小能耗为优化目标,设计了一个适应度函数来寻找每个区域中的最优节点作为中继节点,通过中继节点所在的不同路径并行转发数据。仿真结果表明,该算法相较于其他负载均衡算法可以更好地降低节点能耗及平均端到端时延,从而使网络负载均衡,有效延长了网络生命周期。     

异构网络负载均衡算法

首先建立异构网络模型,确定了链路负载函数,在此基础上提出了异构网络负载均衡算法。利用该算法合理分配网络带宽并调节适当的参数,使异构网络的负载在较小范围内变化,通过选择负载最小的生成树映射,最终实现异构网络的负载均衡。仿真实验表明,让用户在不同网络间的切换可使网络带宽优化分配、网络负载达到均衡,证明了该算法在异构网络中的有效性。     

一种基于确定性调度的工业无线网络路由算法

现有无线通信技术和无线传感器网络中的路由协议无法完全满足工业现场应用需求.为了解决工业无线网络中数据通信的确定性、可靠性和实时性等问题,提出了一种基于确定性调度与链路质量的前k优路径路由算法,根据IEEE802.15.4的工业无线网络DL子网的特点,选取传输延时和链路质量作为路径选择的评价标准.通过算法的实现、仿真分析以及测试,结果表明:该算法有效的改善了通信过程中的确定性、高可靠性等问题,并降低了网络开销、节省了网络资源.     

无线传感网络测量的目标预测动态能量优化

能量约束是无线传感网络实际应用的关键问题之一。针对无线传感网络测量的能效性问题,提出目标预测动态能量优化方法,采用粒子滤波算法对测量目标状态进行预测,通过动态唤醒无线传感节点延长节点睡眠时间节省节点能量。根据无线传感网络节点分布计算能力,运用分布式遗传模拟退火算法优化目标测量过程,使网络能耗最小化。重点讨论机动目标跟踪应用,实现目标位置预测、节点睡眠状态规划和测量节点优化选择,提出节省通信能量的中转节点路由方案。机动目标跟踪的仿真试验表明,目标预测动态能量优化方法能降低节点能耗,并提高无线传感网络的能量有效性。     

基于无线网络状态时延的控制器性能研究

为了研究无线网络控制系统在不同网络负载下时延对系统性能的影响，首先根据无线网络负载状态对网络时延进行分析，给出系统的数学模型，并结合网络负载状态对系统模型作了分析，然后给出了控制器性能指标，利用DLQR（离散线性二次最优设计）方法优化控制器，并就时延对控制性能的影响进行了分析，实现了通过对网络负载状态的调节使系统控制器性能达到最优。最后应用数学模型，通过仿真验证了该研究方法和结果的有效性。     

On the Relation of Load to Average Gap in the Contact Between Surfaces with Longitudinal Roughness

A computer simulation model for the contact between longitudinally-oriented rough surfaces has been formulated. This model closely duplicates the actual surf ace contact deformation behavior by taking into account the elastic interactions between the asperities. There were no assumptions made about the shapes, or any deformation behavior of the asperities, except for their obeying the laws of elasticity. The plastic deformations on the high asperity peaks were taken into account by setting a ceiling on their contact pressures at the material hardness value. The simulations used real surface profiles which were digitized from unworn circumferentially ground steel surfaces. Each pair of these profiles was mathematically combined to form an equivalent rough profile pressing against an infinitely rigid flat and having the appropriately adjusted elastic modulus. A total of 28 different pairs of profiles were used in the simulations. Each contacting pair was subjected to 30 different load levels and the local contact pressures and deformations were calculated. The contact simulations yielded some important mathematical relationships between parameters, such as the real area of contact, average gap, and average asperity load through statistical curve fitting. Two analytical functions were generated to relate the average load to average gap and the real area of contact to load.     

三绕组变压器的双绕组等效建模及在Matpower中的应用

针对实际电网存在着大量的三绕组变压器,但国际上一些著名商业软件,如BPA仿真软件、Matpower这一权威潮流计算开源软件,均只提供双绕组变压器模型,限制了其在具有三绕组变压器的电力系统中的应用的问题,潮流计算是自主开发的电力系统各种应用软件的核心模块,因此依托国际权威开源程序进行二次开发,是一种较好的选择。对Matpower要求的数据格式进行了归纳,对变压器的一般的等值电路及带理想变压器的等值电路和带标幺值的等值电路进行了分析研究,提出了三绕组变压器转换为双绕组等效模型的建模方法,使得原先只适应双绕组变压器的潮流计算软件可以适用于三绕组变压器电网的潮流计算;最后以Matpower软件为例进行了案例计算,并用PSASP仿真软件进行对比验证。研究结果证明,所提出的建模方法是有效的。     

电站锅炉模糊风险评价方法研究与应用

针对电站锅炉风险等级评价问题,将模糊综合评价技术应用到电站锅炉风险等级评价中。开展了电站锅炉失效影响因素及模糊评价因素的重要程度分析,建立了一套科学合理适于在线评价的电站锅炉风险评价体系,提出了模糊综合评价技术与改进的模糊层次分析法相结合的模糊风险评价方法,利用改进的模糊层次分析法计算了指标体系中各层指标权重。对某一台电站锅炉的实际运行工况影响子因素进行了模糊风险评价,采用模糊合成算子进行模糊综合运算得到电了站锅炉运行工况影响子因素的评价向量。研究结果表明:电站锅炉的运行工况影响子因素的风险评价等级为第6级,失效可能性等级为小,该电站锅炉运行工况良好。     

交通荷载作用下桥梁结构参数识别方法

应用动力节点加载法,将作用在桥梁上的交通荷载转化为等效节点荷载,再用两步构造法识别结构物理参数.第1步,用Newmark-β方法变换结构运动方程,并用结构的加速度响应求得变换空间内的位移、速度和加速度响应;第2步,基于最小二乘原理,构造出变换空间内求解结构参数的递推式,进行结构物理参数识别.数值模拟结果表明,在交通荷载作用下,该方法能够快速、准确地进行桥梁结构参数识别.     

Quantum Cooperative Robotics and Autonomy

The intersection of Quantum Technologies and Robotics Autonomy is explored in the present paper.The two areas are brought together in establishing an interdisci...     

考虑进油孔有限长滑动轴承油膜力的近似解析解

针对具有进油孔的有限长滑动轴承油膜力求解问题,采用变分原理和分离变量法,求得了有限长滑动轴承油膜压力分布的近似解析表达式。将油膜压力分布的近似解析表达式在油膜存在区域上进行积分,即得到了油膜力。将提出的计算有限长滑动轴承油膜力方法与无限长轴承模型、有限元方法的计算结果进行了比较,发现了提出的方法与有限元方法的计算结果很接近。最后,研究了进油孔位置和进油压力对油膜存在区域、油膜力等的影响,研究结果表明进油孔位置和进油压力对油膜存在区域和油膜力有较大的影响。     

RLS and LMS blind adaptive multi-user detection method and comparison in acoustic communication

RLS and LMS blind adaptive multi-user detection algorithm and multi-user detector was proposed to solve the problem of multi-user signal detection problem encountered in underwater acoustic communication networks.In simulation analysis,RLS and the LMS blind adaptive multi-user detector were designed and tested for synchronous and asynchronous multi-user communication process.The results of SIR comparison and MMSE comparison show that,both of the two methods can realize blind adaptive detection when any user change in multi-user communication,during this process,the training communication sequences are not needed.The RLS algorithm has about 5 dB higher in SIR compared with LMS algorithm,and the convergence velocity of RLS algorithm is also higher than LMS algorithm when the communication users change.RLS algorithm has better ability in multi-user detection than that of LMS algorithm,and it has great attraction and guiding significance for solving the problem of multiple access interference(MAI) in multi-user communication.     

Robust Impedance Control of Robots Using an Adaptive Interaction Force Observer

For robot interaction control,the interaction force between the robot and the manipulated object or environment should be monitored.Impedance control is a type ...     

Research on key techniques of expendable conductivity temperature depth measuring system

This paper analysis the developing of expendable conductivity temperature depth measuring system(XCTD)and introduce its principle of measuring about temperature,salinity and depth of ocean.Some key techniques are put forward.According to the real needs of XCTD,conductivity sensor with high sensitivity is designed by principle of electromagnetic induce,the ocean conductivity from induced electromotive force has been calculated.Adding temperature correction circuit would help to reduce error of conductivity measurement because of sharply changing temperature.Advanced temperature measuring circuit of high precision and the constant current source is used to weaken effect of self-heating of resistance and fluctuation of the source.On respect of remote data transmission,LVDS is a good choice for the purpose of guarantee the quality of data transmitted and the transmission distance is reaching to thousand meters in the seawater.Modular programming method is also brought into this research aimed at improve the stability,reliability and maintainability of the whole measuring system.In February,2015,the trials in South China Sea demonstrate that the developed XCTD realize effective measurement at a speed of 6 knots and detection depth at 800 m.The consistency coefficient of the acquired data is greater than 0.99 and the success rate of probe launching is above 90%.     

CHARACTERISTCS OF FLUID FILM IN OPTIMIZED SPIRAL GROOVE MECHANICAL SEAL

In order to investigate the sealing performance variation resulted from the thermal deformation of the end faces, the equations to calculate the fluid film pressure distribution, the bearing force and the leakage rate are derived, for the fluid film both in parallel gap and in wedgy gap. The geometrical parameters of the sealing members are optimized by means of heat transfer analysis and complex method. The analysis results indicate that the shallow spiral grooves can generate hydrodynamic pressure while the rotating ring rotates and the bearing force of the fluid film in spiral groove end faces is much larger than that in the flat end faces. The deformation increases the bearing force of the fluid film in flat end faces, but it decreases the hydrodynamic pressure of the fluid film in spiral groove end faces. The gap dimensions which determine the characteristics of the fluid film is obtained by coupling analysis of the frictional heat and the thermal deformation in consideration of the equilibrium condition of the bearing force and the closing force. For different gap dimensions, the relationship between the closing force and the leakage rate is also investigated, based on which the leakage rate can be controlled by adjusting the closing force.