一种非正交多址接入迭代优化混合预编码算法

为了使大规模毫米波(millimeter wave, mmWave)多输入多输出(multiple-input multiple-output, MIMO)系统获得高频谱效率和高能量效率,采用非正交多址接入迭代优化算法和簇首选择算法,研究了无线携能通信场景中的混合预编码问题。仿真结果表明：与传统正交多址接入无线携能通信的混合预编码算法相比,所提算法能够获得更高的频谱效率和能量效率。     

A novel QoS supported cooperative diversity algorithm for IEEE 802.11 WLAN

A new cooperative diversity algorithm with quality of service （QoS） awareness for wireless local area network （WLAN） is proposed. According to this protocol, cooperation is invoked only if a direct transmission cannot meet user-specific QoS requirements. If cooperation is implemented, partner choice depends on who can achieve the minimum data rate required to have a successful transmission. The closed-form expressions for the system throughput and the power consumption are provided. Theoretical analysis and simulation results indicate that the QoS-aware cooperative scheme can significantly improve the system performance in terms of throughput and energy efficiency by avoiding negative effect of unconditional cooperation.     

一种用于接收器的高精度片上匹配电阻电路

接收器电路是高速串行接口电路中关键模块.基于数字化模拟电路和负反馈动态调整技术设计了一种用于高速串行接口USB2.0接收器的高精度片上匹配电阻电路.使用TSMC(Taiwan Semiconductor Manufacturing Company Ltd)的CMOS 0.25 um混合信号模型,在Cadence软件环境下用spectre仿真器模拟,结果表明在500Mbps的高速时钟信号作用下,所设计的匹配电阻阻值稳定在[44.3Ω,45.6Ω]范围内,最大稳定时间6μs,平均误差±1.45%,最大误差1.56%;整合了这种高精度片上电阻的USB2.0接收器可以正确接收500 Mbps高速串行数据.     

基于改进单神经元梯度学习的无线网络主动队列管理

考虑传统网络拥塞控制忽略了网络拥塞的持续状态, 引入将数据包到达链路速率作为控制器输入的方案, 得到一种改进单神经元梯度学习(improves single neuron gradient learning, ISNGL)的主动队列管理算法. ISNGL 算法采用梯度学习动态调整网络参数, 并在此基础上对收敛速度和稳定性加以改进, 提出带有位移参数的新激活函数和带有权值调整的动量项的改进方法, 最后通过 NS2 网络仿真软件在无线网络的拓扑模型上进行仿真分析, 结果表明 ISNGL 算法在无线网络环境下拥有良好的拥塞控制能力.     

柔性直流输电系统可靠性评估中薄弱环辨识及备用

文章根据Markov过程的基本原理和累积状态间转移频率性质,建立了柔性直流输电系统的数学模型,采用定量的分析方法,就柔性直流输电系统中的薄弱环进行分析,并给出了相应的增强性措施;对系统在不同备用水平下的可靠性指标进行了分析比较,得出了系统在元件采用1备用的情况下,可以取得较理想的可靠性指标和经济性指标。     

Relative Entropy of Distance Distribution Based Similarity Measure of Nodes in Weighted Graph Data

Many similarity measure algorithms of nodes in weighted graph data have been proposed by employing the degree of nodes in recent years. Despite these algorithms obtaining great results, there may be still some limitations. For instance, the strength of nodes is ignored. Aiming at this issue, the relative entropy of the distance distribution based similarity measure of nodes is proposed in this paper. At first, the structural weights of nodes are given by integrating their degree and strength. Next, the distance between any two nodes is calculated with the help of their structural weights and the Euclidean distance formula to further obtain the distance distribution of each node. After that, the probability distribution of nodes is constructed by normalizing their distance distributions. Thus, the relative entropy can be applied to measure the difference between the probability distributions of the top d important nodes and all nodes in graph data. Finally, the similarity of two nodes can be measured in terms of this above-mentioned difference calculated by relative entropy. Experimental results demonstrate that the algorithm proposed by considering the strength of node in the relative entropy has great advantages in the most similar node mining and link prediction.     

无线传感器网络动态调度分簇算法

提出了一种基于K均值的无线传感器网络动态调度分簇算法(DSCA),不但考虑了能量感知这一重要问题,还针对无线传感网络的稳定性和可靠性,提出了节点的同步失效概念,通过采用K均值得到更加平衡的分簇,使得能量消耗更加平衡.该算法发展了一种基于信号接收强度指标(RSSI)而无需知道节点坐标的簇质心求解方法,提出了基于局部信息集中的动态多簇头选举机制和动态时分复用(TDMA)通信轮数分配机制,这些机制使无线传感网络的能量消耗达到了高度均衡,保证了节点的同步失效,提高了传感网络的稳定性和可靠性.仿真结果表明,算法可以减少约70%的簇重构次数.     

基于SoRCA结构的SBORA路由算法

针对无线传感器网络SoRCA结构中路由算法存在流量负载不均衡和鲁棒性问题,提出了SBORA路由算法.该算法根据SoRCA拓扑的结构化特点,计算出源点到目的点的最优路径在各传播反向所需跳数,然后根据跳数特征,通过二次概率路由选择策略,从多条优化路径中迅速给出一条由源点到目的点的路径,并根据包中跳数的特征,给出数据传输失败时新路由的选择.通过性能分析和仿真试验表明,基于SoRCA结构的SBORA路由算法具有较好的流量负载均衡性和鲁棒性.     

动态优化速率和帧长的超宽带链路自适应算法

超宽带系统因发射功率受限,其传输速率对通信距离和信道衰落十分敏感。针对这一特性,以提高媒体访问控制(M AC)层吞吐量为目的,提出了一种基于接收端估计的链路自适应算法。该算法由接收端通过在线动态优化得出实际信道中给定信噪比估值下最佳的传输速率和M AC净荷长度,并通过应答帧附带的方式通知发送端。仿真结果表明,该算法较已有算法提高了吞吐量近30%。该算法复杂度低,对信噪比估计误差不敏感,具有一定的应用潜力。     

基于积累线性模型的证券单笔交易模型

积累线性模型是处理自变量为连续变量、因变量为离散变量时的常用方法。而单笔交易中证券价格的变动为离散变量,本文采用积累线性模型为其建模,得到了在一定的交易方向和交易量下,证券价格变动的条件概率分布。理论与实证结果均显示,积累线性模型更适合用于建立单笔交易模型;其中序次Logisic回归又比序次Prob it回归的拟合效果更好。使用积累线性模型建立的证券单笔交易模型具有良好的应用前景。