普适计算研究

随着计算技术、网络技术和无线传感器技术的发展和渗透,嵌入式计算和通信设备的快速兴起,一种全新的计算模式—普适计算正在兴起和发展。文章首先描述普适计算的产生和发展历程,接着对其所研究的相关内容和核心技术进行详细介绍,然后分析其计算模式特点和关键研究领域,最后给出普适计算发展中所面临的安全性问题和相应的应对措施。     

基于拉格朗日的计算迁移能耗优化策略

随着移动网络技术的发展和智能终端的普及应用,移动边缘计算已成为云计算的一个重要应用。计算迁移策略已成为移动边缘计算服务的关键问题之一。以移动终端总的计算时间和移动终端能耗最小化为目标,将移动终端的计算迁移资源划分问题建模为一个凸优化问题,运用拉格朗日乘子法进行求解,提出基于阈值的迁移优化策略模型。仿真实验表明,本迁移优化策略模型能有效平衡本地计算和迁移计算之间的关系,为移动边缘计算中执行计算密集型应用提供保障。     

满足本地化计算的集群资源调度策略

将本地化计算分成节点本地化计算和机架本地化计算2个层次,分别称作节点本地化计算和机架本地化计算。结合主导资源公平调度策略DRF和Delay调度约束机制提出一种满足本地化计算的集群资源调度策略DDRF,旨在既能达到一个较高的本地化计算水平,又能保证资源调度的“公平性”。通过数据实验分析了在DDRF调度策略下本地化计算延迟对作业执行效率的影响。     

嵌入式技术将成为AMD未来发展的杀手锏

数据咨询公司IDC的数据显示,物联网、环绕计算和新一代嵌入式系统将成为计算行业今后取得重大发展的强劲动因。十年前的计算市场是互动性计算,现在已经步入环绕计算时代。在环绕计算时代,网络连接无处不在,计算环     

隐私保护的可验证多元多项式外包计算方案

随着云计算的发展和大数据时代的到来,如何对隐私数据进行外包计算且有效验证计算结果具有重要的现实意义。基于多线性映射和同态加密方案,提出了可验证的多元多项式外包计算方案,用户可准确验证外包计算结果的正确性。方案在标准模型中可证安全,且多项式函数和用户输入对于服务器都是保密的。分析表明,用户计算量远小于服务器的计算代价以及直接计算多项式函数。     

用AIM快速计算电大尺寸物体的散射特性

如果使用传统的矩量法计算电大尺寸物体的电特性,需要很大的存储量和计算量,本文采用AIM(自适应积分方法)减少所需的存储量和计算量。使用AIM计算了导体平板的RCS,与传统的矩量法相比大大减少了计算时间和存储量,显示了AIM在计算电大目标特性时的优越性。     

工信部:加快推动边缘计算等产业热点发展

<正>近日,2017边缘计算产业峰会在北京召开。工业和信息化部信息化和软件服务业司司长谢少锋出席会议并致辞。边缘计算是工业互联网的重要技术支撑。作为新型的数据计算架构和组织形态,边缘计算扩展了网络计算的范畴,将计算从云中心扩展到了网络边缘,为用户就近提供智能服务。在制造业数字化、网络化、智能化转型过程中,边缘计算可以满足用户在敏捷连接、实时计算、数据反馈、应用智能、安全与隐私保护等方面的关键     

典型大数据计算框架分析

认为大数据计算技术已逐渐形成了批量计算和流计算两个技术发展方向。批量计算技术主要针对静态数据的离线计算,吞吐量好,但是不能保证实时性;流计算技术主要针对动态数据的在线实时计算,时效性好,但是难以获取数据全貌。从可扩展性、容错性、任务调度、资源利用率、时效性、输入输出(IO)等方面对现有的主流大数据计算框架进行了分析与总结,指出了未来的发展方向和研究热点。     

移动边缘计算规模部署的技术制约因素和对策

指出了边缘计算规模落地的制约因素,具体包括计算、连接、部署位置和设备形态。认为移动边缘计算需要平衡"计算"和"连接"。通过对边缘计算的针对性研究,中兴通讯给出了相应的软硬件解决方案,并提出与整个业界紧密合作、共同推进边缘计算产业发展的愿望。     

基于GPU 的二维FDTD 并行计算

由于稳定性条件的要求和采用Yee 元胞体离散的方式求解Maxwell 方程,用FDTD 计算目标电磁散射时需要 消耗大量的计算资源,计算往往需要较长时间。采用并行技术是提高计算效率的有效途径,本文基于计算统一架构 CUDA 模型,给出了利用图形处理器（GPU）实现二维FDTD 并行计算的实现方法。给出了二维Mur 边界和PEC 边界 的数值算例,计算结果表明,采用GPU 计算大大的提高了计算效率。     

Crosstalk between microstrip transmission lines

Methods for prediction of crosstalk between microstrip transmission lines are reviewed and simplified for the weak-coupling case. Classical coupled transmission line theory is used for uniform lines, and potential and induced EMF methods are used for crosstalk between nonuniform lines. It is shown that the potential method is equivalent to classical coupled transmission line theory for the case of uniform lines. An experiment was performed for uniform coupled microstrip lines for frequencies from 50 MHz to 5 GHz, and good agreement between theory and measurement was obtained for both near- and far-end crosstalk     

非均匀有耗传输线ABCD参量的求解

传输线理论是射频与微波电路的重要基础理论,而其中ABCD参量特别适用于分析级联网络的传输性能.本文针对非均匀有耗传输线的ABCD参量求解问题,建立传输线的数学模型,给出了三种解法,即级联法、微分方程法和积分方程法,并对三种方法的准确性和效率进行了讨论.     

特高压交流电力线路仿真模型的创建

特高压电力线路运行特性不同于一般高压电力线路,进行特高压交流电力线路特性研究需要创建电力线路仿真模型。文章以均匀传输线理论为基础,对特高压电力线路4个参数进行分析,得出特高压交流电力线路单位长度电导G0表达式,推导得出特高压交流电力线路考虑分布参数特性的数学模型,并在Matlab仿真软件平台创建仿真模型,为特高压长距离电力线路运行特性研究奠定基础。     

低压电力线信道建模与蒙特卡洛模拟

在分析均匀传输线信道特性的基础上,引入二端口网络理论,分析低压电力线带负载信道的传输特性。采用二端口网络理论的T参数传输矩阵建立了低压电力线信道传输模型,然后利用蒙特卡洛方法建立仿真模型。模型从不同负载特性、不同接入或撤出负载变化量、不同传输信号频率对信号的影响分别进行了仿真和分析。仿真结果表明,采用二端口网络理论建立起的信道模型是可行的;采用蒙特卡洛数值模拟方法模拟低压电力线带负载信道是除了实际测试信道之外又一个可以借鉴的方法。     

Analysis of radiation characteristics of a finite-lengthtransmission line using a circuit-concept approach

The radiation phenomenon from a transmission line of finite length is described. Based on the hypothesis of reciprocity between the coupling of an external wave to a transmission line and the radiation from a transmission line, a set of models for both phenomena is implemented using a six-terminal network. The goal is to find out what current is induced in each terminal load of the network. The radiation characteristics of finite-length lines such as radiation fields, radiation power-density, and radiation coefficients are considered. Experiments using both straight lines and bent lines have been performed to validate the theory     

Application of equivalent circuit concepts to evaluate the amplitude of induced disturbances to the ends of printed circuit traces

The paper proposes a method to calculate parameters of equivalent sources induced on printed circuit traces. These parameters will be obtained taking into account the combination of several approaches: the induction law when the trace size is small as compared to the wavelength of the disturbances, and transmission lines theory in the opposite case. Nevertheless, the confrontation with a more precise evaluation, obtained using the theory of diffraction by conductors, reveals that it is necessary to make corrections to the transmission lines theory, in particular, when evaluating the resonant frequencies and the amplitude of induced parasites at these frequencies. We will introduce special boundary conditions as well as radiation mechanisms.     

Design of Interdigitated Capacitors and Their Application to Gallium Arsenide Monolithic Filters

Theoretical expressions for the interelectrode capacitance and conductor losses for an array of microstrip transmission lines are presented. The effect of finite conductor thickness is included in the analysis by introducing equations for the effective width of the transmission lines. Good agreement between theory and experiment is observed up to 18 GHz. Experimental results obtained from a lumped-element GaAs monolithic bandpass filter are in excellent agreement with theory. The filter has 1.5-dB insertion loss at 11.95 GHz and greater than 22-dB loss in the stopband. The filter measures 0.58x 1.3x0.203 mm.     

传输线参数提取和瞬态响应分析

利用传输线的基本原理推导出半无限长传输线的瞬态响应,总结出传输线在高频下的基本特性,接着对双线传输线这一特定情况提取传输线的分布参数,然后应用提取结果进行传输线Hspice仿真,进而得出传输线的时域特性。     

Duality transformation for nonreciprocal and nonsymmetrictransmission lines

Duality transformation is introduced to the theory of generalized (nonreciprocal and nonsymmetric) transmission lines making it possible to find solutions to problems in terms of solutions to dual problems without having to go through the solution process. The generalized transmission lines have emerged when more general media have been introduced to classical waveguide geometries, for example, microstrip lines on chiral substrates. It is seen that there actually exist two duality transformations and the self-dual voltage and current solutions are propagating waves in the transmission line. The transformation can be, e.g., applied to transform a nonsymmetric transmission line to a symmetric one     

手征介质填充双平板中导模的反射和透射特性

用多模网络与严格模匹配相结合的方法,对纵向填充一层、两层和多层手征介质的双平板中导模的反射和透射特性进行了分析和求解.分析中在横截面采用等效传输线,在纵向采用多模传输线方法,并且利用结构的对称性使得问题简化.对各种不同情形进行了数值计算,讨论了手征参数和波导结构的尺寸对反射和透射特性的影响.