基于主客观权重的异构网络选择算法

为解决在异构网络环境选择最佳的接入网络问题,提出一种结合综合赋权的异构网络选择算法。在用户端采用层次分析法判断用户偏好,在网络端采用基于指标相关性的客观赋权法判断网络客观状态,并结合基于离差极小化的综合赋权法得到最终权重,同时运用理想值近似排序法进行网络排序,接入最佳网络。基于Matlab的仿真结果表明,该方法能根据不同业务结合网络性能及用户需求选择最佳的接入网络,减少了频繁切换,提高了网络选择结果的合理性与有效性。     

LEACH协议最佳群首个数的研究

低能耗自适应分簇(LEACH)协议随机循环地选择群首并将网络能量消耗平均分配给每个节点,但没有考虑选择的群首个数是否在最佳群首范围内。为了避免网络中群首节点数较少或较多而导致节点过早死亡,结合节点数据融合率并以单跳与多跳相结合的方式将数据发送给基站的方法确定最佳群首个数。当网络中的分群个数与最佳群首个数相同时,可以提高网络生命周期,节约网络能耗。     

无线传感器网络三维空间最佳覆盖路由协议

本文针对新兴无线传感器网络中的三维空间随机最佳覆盖NP难问题进行了研究.采用计算几何与图论着色方法建立了三维空间的随机最佳覆盖数学模型,给出了一种分布式启发算法,得到了完成最佳覆盖的低能量消耗路径.并在此基础上设计了一种可以实现无线传感器网络三维空间最佳覆盖的优化路由协议.最后进行了协议算法的性能评价以及最佳覆盖和网络生存时间的实验仿真,结果表明协议算法时间复杂度低,并具有可扩展性、有效性和鲁棒性.     

LEACH协议中的最佳建簇概率

无线传感器网络中,传感器节点是通过携带能量有限的电池供电,因此如何有效利用能量,延长节点的生命周期是无线传感器网络首要研究的问题。为了达到降低网络能源消耗的目的,本文在第一顺序无线电模型的基础上利用能量消耗的关系得到了典型分簇路由协议LEACH的最佳建簇概率。研究结果表明,当分簇数目小于最佳建簇数目时,传感器网络每轮消耗的总能量就会以指数方式增加,说明确立最佳建簇数目可以降低网络能耗,从而提高无线传感器网络的整体生存时间。 更多还原     

直接序列码分多址通信系统中最佳多用户检测器的一种实时实现方法

本文叙述了通过构造一种复合神经网络实现直接序列码分多址通信系统中实时最佳多用户检测器的方法。这种最佳多用户检测器的实时性来自复合神经网络运算结构的并行性。复合神经网络由一个前向单层网络和一个竞争网络构成，其中前向单层网络进行似然函数计算，而竞争网络实现选择最大项操作。     

Ku波段GaN MMIC高线性功率放大器设计

设计了一款Ku波段工作频率为13.0~15.5GHz的GaN MMIC高线性功率放大器,采用0.25μm GaN HEMT工艺,电路采用两级放大器的结构。通过两种不同的末级匹配网络的设计,对比分析匹配网络的设计对功率放大器效率与线性度的影响。一种是匹配到最佳功率附加效率(PAE)的末级匹配网络,一种则是匹配到最佳线性度的末级匹配网络(用最佳三阶交调产物与载波比值(IM3)来表示),级间和输入级匹配网络也尽量达到低损耗、高线性指标,从而提高整体电路的线性度,并尽量使得效率不恶化。测试结果表明,功率放大器的最大输出功率可以达到37.5dBm,匹配到最佳PAE的功率放大器功率附加效率均大于32%,最大可以达到36%,匹配到最佳IM3的功率放大器PAE低了2到4个百分点,线性度指标IM3则高了1到2个dBc。该测试结果表明,对于高线性功率放大器,末级匹配网络可以在最佳PAE点的基础上适当地向最佳IM3点靠近,以逼近更好的线性度指标,但若距离最佳IM3太近,PAE则会有较大的恶化。     

基于主客观权重的异构网络选择算法

为了解决在异构网络环境选择最佳的接入网络的问题,提出一种结合综合赋权的异构网络选择算法.在用户端采用层次分析法判断用户偏好,在网络端采用基于指标相关性的客观赋权法判断网络客观状态,结合基于离差极小化的综合赋权法得到最终权重,并运用理想值近似排序法进行网络排序,接入最佳网络.基于matlab的仿真结果表明：该方法能根据不同业务结合网络性能及用户需求,减少频繁切换,提高网络的选择结果的合理性和有效性.     

CATV用户分配网的优化设计

介绍CATV用户分配入户网络的设计方法，详细分析用户分配入户网络的电平误差，提出用户分配入户网络的最佳设计方法。     

厂商动态

华为Small Cell获北美“最佳网络基础设施解决方案”大奖 近期,华为在北美通信大会暨展览颁奖典礼上,凭借Small Cell解决方案荣获“最佳网络基础设施解决方案”大奖。Small Cell解决方案通过话务地图,能够识别出网络中的热点和盲点地区,从而实现对热点区域的增强覆盖,以及盲点区域的补盲覆盖,最终提升网络容量。     

华为信息

华为获“LTE最佳商用表现”和“LTE最佳网络设备”两项大奖：在最近举办的“2011年LTE全球峰会”上，华为荣获“LTE最佳商用表现”和“LTE最佳网络设备”两项大奖。LTE全球峰会是LTE领域级别最高、规模最大的全球峰会；该峰会颁发的奖项是LTE业界的顸级荣誉．是对LTE产业作出巨大贡献的组织和个人的最高褒奖。     

Synthetic-Aperture Radar Based on Nonsinusoidal Functions: X-Array Gain, Planar Arrays, Multiple Signals

Beam forming based on a line array of sensors and radio signals with a triangular autocorrelation function was discussed in Part IX of this series. The resolution angle e was shown to vary like 1/?P/PN with the signal-to-noise ratio P/PN, which puts a premium on getting the best possible signal-to-noise ratio. This paper shows that the signal-to-noise ratio holding for one sensor can be replaced by the signal-to-noise ratio holding for the whole array, which usually is referred to as making use of the array gain. The result is generalized from the one-dimensional line array to the two-dimensional planar array. Furthermore, the method of beam forming is extended from signals returned by point-like scatterers or reflectors to structures composed of several point-like scatterers; the utilization of the array gain has not yet been investigated for this case.     

网络环境下的品牌溢价效应的影响因素研究

在虚拟网络环境下，产品信息通过网络快速传播，海量的网络信息使得那些非知名的品牌被淹没在信息海洋中。本文通过对品牌及品牌溢价的理论知识介绍，得出品牌作为产品的标志是可以溢价的。在分析传统环境下对品牌溢价影响因素的基础上，详细分析了网络环境下的影响因素，并提出了提升网络环境下品牌溢价的策略，为企业的实际营销活动提供参考。     

A Printed Circuit Balun for Use with Spiral Antennas

A novel printed circuit balun is described which is particularly well suited to applications where space is at a premium. The design utilizes unshielded strip transmission line, but is readily adaptable to all of the common printed circuit transmission line techniques. When the balun is housed within the cavity of a spiral antenna, boresight error is virtually eliminated, ellipticity ratios of less than 2 db are maintained over an azimuth angle greater than /spl plusmn/ 60/spl deg/, and the input standing-wave ratio is less than 2:1 over an octave frequency range. Experimental results are given and additional applications are described.     

基于ARIMA模型自动预测我国保险行业保费收入的应用和实践

本文采用ARJMA模型以我国财产险的保费收入的预测为例,对数据预处理、模型的选择、识别、估计、检验等过程进行了详细的分析,得出了预测结果报告,并描述了对我国产寿险的保费收入实现自动预测并得到结果报表的思路和方法。     

声表面波卷积器／存储相关器用ZnO膜的制备

本文介绍了声表面波(SAW)卷积器/存储相关器用优质氧化锌(ZnO)压电膜的制备方法。用平面磁控溅射技术溅射ZnO陶瓷靶沉积出了激励SAW西沙瓦模式的优质ZnO膜。用同轴磁控溅射技术溅射ZnO陶瓷靶沉积出的优质ZnO膜制作ZnO/Si单片式SAW卷积器,使该器件性能进一步改善,同时给出了相应的实验结果。     

Access to premium content on mobile television platforms: The case of mobile sports

As broadcasting sports content has proved to be a popular strategy for driving the growth of the digital premium content marketplace in the past, mobile service operators aim to enter the sports rights market. However, as the markets for live sports broadcasting are still dominated by established broadcasters, mobile network operators are facing significant barriers to access premium content creating bottlenecks in the construction of business models. Therefore, content regulation is seen as essential for the development of mobile television platforms. This article aims to stress the strategic importance of content in the development of sustainable business models for mobile broadcasting services and will discuss the implications of bundling strategies and regulations for the viability of these emerging platforms.     

基于Internet的网络辅助教学在电路课程中的应用

随着课程改革的推进,作为专业基础课的电路原理面临既要减少课内学时,又要增加学生学习信息量的矛盾。为了最大限度地满足教学需要,实现优质教学资源共享,重庆大学电路原理课程组开发了基于Internet的电路原理课程及精品教材网站。网络具有信息量大、更新快、跨越时间和空间、资源共享等特点,有利于将以“教”为中心的传统教学模式和以学为中心的“主动学习模式”有机地结合起来,使两者起到相互补充的效果。     

Constrained power control

High system capacities can be achieved by controlling the transmitter power in multiuser radio systems. Power control with no constraint on the maximum power level has been studied extensively in earlier work [1–18]. Transmitter power is at a premium in radio systems such as cellular systems and PCS. There is a limit on the maximum transmitter power especially at the terminals (e.g. mobile units and handsets) since the power comes from a battery. In this paper we study power control that maximizes the minimum carrier to interference ratio (CIR), with a constraint on the maximum power. The optimal power vector solution lies on the boundary of the constrained power vector set and achieves a balance in the CIR's. Results indicate that the constraints do not induce any stability problems. A distributed scheme with favourable convergence properties and close to optimum performance is presented. Simulation results show that the algorithm tries to maximize the number of terminals served with CIR greater than or equal to the target CIR, while conserving power.     

Cantronic Systems＇ IR Vandal-Proof Camera Provides Reliable Surveillance In Daylight and No Light Environments

The IR Vandal Proof Dome Camera for daylight, low-light and no-light CCTV applications is ideal for installations where space is at a premium. Its die-cast aluminum housing and vandal-resistant polycarbonate dome shields the camera from the hazards in punishing environments like schools, factories and prisons.     

High Reliability Electronic Parts as Justified System Cost Elements

The planned use of premium electronic parts in a forthcoming system is a logical means for assuring failure-free operation comensurate with the best state-of-the-art. However, an over-all analysis of the value of premium parts must show the net worth of improved system performance to more than offset the added initial parts cost. These costs may be in higher procurement costs, added test and evaluation, or more intangible investments. At the outset, a system-production strategy must establish the best level of investment in such features, based upon a conviction that the ``impact' upon reliability improvement will justify the added initial costs. This paper treats the difficult problem of evaluating the system reliability ``impact' introduced by increased parts reliability. The necessity for an early investment strategy will limit the level of analytical sophistication available for predicting reliability. Thus, it is useful to examine the validity of reliability ``parts population analyses' as first-order justifications for investing in high reliability parts for complex electronic systems.