Cognition Flow in Cognitive Radio Networks

This paper introduces the research progress on the cognition flow in the National Basic Research Program of China （973 Program） under Grant No. 2009CB320400 ＂Research on Basic Theories and Key Technologies of Cognitive Radio Networks＂. We present the motivation behind the proposal of the concept of cognition flow, provide the definition, discuss the features, behaviours, representations, math- ematical models, and the functions of cognition flow in Cognitive Radio Networks （CRNs）. We also analyse how the cognition flow promotes the convergence of heterogeneous networks. Our group also constructed the test platform to verify the usefulness of cognition flow. The results that were simulated by computers and tested on the platform both confirm that cognition flow can realise efficient interaction of cognitive information among heterogeneous networks in CRNs, which contributes to the seamless convergence of heterogeneous networks, and significantly improves the spectrum efficiency and users＇ Quality of Experience （QoE）.     

声波团聚中尾流效应的理论研究

声波团聚是一项非常有潜力的颗粒物排放控制技术,最近的实验表明声波尾流效应是其中的重要机理。研究建立了Oseen条件下声波团聚中的尾流效应理论模型,并采用数值方法进行求解。研究了颗粒夹角、粒径和频率对声波尾流效应下的聚合速度的影响。计算结果表明,颗粒与声场的夹角对聚合速度影响很大,存在吸引和排斥两个区域。当夹角为0°~50°时,颗粒间存在强吸引作用,颗粒与声场平行时,聚合速度达到最大值;当夹角为50°～90°时,颗粒间表现为弱排斥作用,颗粒与声场垂直时,排斥速度最大。聚合速度随频率的增大而增加,但当频率超过某一临界值时,聚合速度基本保持不变;颗粒粒径越大,该临界频率越低。随着颗粒粒径的增大,聚合速度基本呈线性增加。     

Should mobile Internet be an extension to the fixed web? Fixed-mobile reinforcement as mediator between context of use and future use

As the fixed and mobile Internet are converging, the question emerges whether consumers expect mobile Internet services to replicate services they know from the fixed Internet. Literature on reinforcement and displacement suggests that the use of new media depends on whether users are inclined to replace or reinforce their existing media use on a new device. This paper analyzes whether the importance that users attribute to using similar services on their mobile phone as on the fixed Internet can explain the intention to adopt mobile services. Specifically, we investigate if such fixed-mobile reinforcement could mediate the impact of personal innovativeness and several dimensions of context. We compare basic Internet services, entertainment services and transaction services. We find that especially the intention to adopt basic Internet services largely depends on the importance of using similar services in the mobile domain as on the fixed Internet. Several context-of-use predictors are partially or even fully mediated by fixed-mobile reinforcement. The results convey a positive message to operators that are betting on converged multimedia services that can be accessed from any device and from any fixed or mobile network.     

基于LACP的链路聚合测试方法研究和实践

基于LACP的链路聚合技术在电信运营商现网部署中被广泛应用,其不仅是一种廉价且有效增加链路带宽的方法,同时也是提高网络稳定性的一种方案.首先简要介绍了LACP的原理,分析了常见应用场景,提出了LACP实验室的验证解决方案,列举了关键参数和测试要点,最后运用网络测试仪进行协议和流量的模拟验证.     

Note on flash and distillation systems

Flash and distillation systems evolving on the equilibrium manifold possess stable steady states when the molar flows and the boundary conditions are fixed and a vapor and liquid phase is present at all times. The results extend the range of validity of a local stability theorem for linear, constant molar overflow systems due to Acrivos and Amundson. The approach to stability analysis is motivated by the tangent plane method developed by Gibbs to open systems as it takes advantage of the negative curvature of the entropy surface to construct a Lyapunov function. © 2013 American Institute of Chemical Engineers AIChE J, 59: 3322–3332, 2013     

下一代家庭宽带互联技术简述

本文分析家庭互联的现状和主要宽带互联技术,总结下一代家庭宽带互联技术的融合发展趋势。     

强跟踪SRCKF及其在船舶动力定位中的应用

针对平方根容积卡尔曼滤波器(SRCKF)在定位系统船舶模型不确定时存在滤波精度下降甚至发散的问题,提出了一种具有强跟踪性能的SRCKF算法.基于强跟踪滤波器(STF)的理论框架,采用三阶球面径向容积规则代替STF中的雅克比矩阵计算,结合渐消因子的等价表述,构建强跟踪SRCKF.基于滤波收敛判据和渐消记忆滤波思想,分析了强跟踪SRCKF的收敛性.强跟踪SRCKF兼具STF鲁棒性强、SRCKF滤波精度高和实现简单的优点,有效克服了STF的理论局限性及SRCKF在系统模型不确定时滤波性能下降的缺点.利用船舶陆上仿真系统进行试验,证明了强跟踪SRCKF的有效性.     

基于现代学徒制的“一制四化”式中高职衔接模式研究

为使中高职无缝衔接,以课程标准为依托,从现代学徒制出发,研究适合中高职业衔接的“一制四化”式模式,达到中职、高职、合作企业的资源共享,中高职衔接专业人才培养质量提高的目的.     

Enhanced Frequency-Domain Frost Algorithm Using Conjugate Gradient Techniques for Speech Enhancement

In this paper, the frequency-domain Frost algorithm is enhanced by using conjugate gradient techniques for speech enhancement. Unlike the non-adaptive approach of computing the optimum minimum variance distortionless response （MVDR） solution with the correlation matrix inversion, the Frost algorithm implementing the stochastic constrained least mean square （LMS） algorithm can adaptively converge to the MVDR solution in mean-square sense, but with a very slow convergence rate. In this paper, we propose a frequency-domain constrained conjugate gradient （FDCCG） algorithm to speed up the convergence. The devised FDCCG algorithm avoids the matrix inversion and exhibits fast convergence. The speech enhancement experiments for the target speech signal corrupted by two and five interfering speech signals are demonstrated by using a four-channel acoustic-vector-sensor （AVS） micro-phone array and show the superior performance.     

变次数B-样条曲线

变次数B-样条（MD-样条）曲线是在不同区间有不同次数的特殊B-样条曲线.为了适应CAD造型系统的发展,研究了最大变化次数小于3的MD-样条曲线.这类MD-样条继承了多项式B-样条的变差缩减性、保凸性等大多数性质,并具有退化性、嵌入节点等独特性质.整个MD-样条曲线至少是Cn-1连续的,这里n为整个曲线段的最小次数.研究了MD-样条与B-样条的关系,可以通过嵌入节点将MD-样条转化为B-样条,同时通过MD-样条能够将B-样条的升阶看成是几何割角的过程.变次数B-样条能够在保持理想精度的条件下,有效地减少控制顶点和节点向量的数目,有利于几何设计和CAD系统的数据传输.