Computing the weight distribution of a set of points obtained byscaling, shifting, and truncating a lattice

A method is developed to compute the weight distribution of a set of points obtained from a lattice. The lattice is scaled (with possibly nonequal factors) along different dimensions, is shifted to an arbitrary point, and its lower dimensional subspaces are truncated within given shaping regions. Each branch in the lattice trellis diagram is labeled by the weight distribution of the corresponding coset incorporating the effects of scaling, shifting, and truncation. The weight distribution is obtained by multiplying the weight distribution of the serial branches and then adding the result over parallel paths     

Cylindrical cell membranes in uniform applied electric fields: validation of a transport lattice method

The frequency and time domain transmembrane voltage responses of a cylindrical cell in an external electric field are calculated using a transport lattice, which allows solution of a variety of biologically relevant transport problems with complex cell geometry and field interactions. Here we demonstrate the method for a cylindrical membrane geometry and compare results with known analytical solutions. Results of transport lattice simulations on a Cartesian lattice are found to have discrepancies with the analytical solutions due to the limited volume of the system model and approximations for the local membrane model on the Cartesian lattice. Better agreement is attained when using a triangular mesh to represent the geometry rather than a Cartesian lattice. The transport lattice method can be readily extended to more sophisticated cell, organelle, and tissue configurations. Local membrane models within a system lattice can also include nonlinear responses such as electroporation and ion-channel gating.     

A counterexample to a Voronoi constellation conjecture

Voronoi constellations are of interest because it is possible to save on signal power by choosing a lattice for which the second moment of the Voronoi region is close to that of a sphere with the same dimensionality. A Voronoi constellation based on the lattice partition Λ/Λ_s is the set of points in some translate Λ+a that fall within the Voronoi region R(Λ_s). G.D. Forney, Jr. (1989) proposed an algorithm for constructing Voronoi constellations and conjectured that this algorithm minimized the average signal power. A two-dimensional counterexample, to Forney's conjecture is presented     

采用栅格理论的多机器人系统任务元管理方法

以目标为研究对象以及传统的传感器管理方法已难以满足多机器人系统中的多传感器管理研究,但如果将目标与系统任务状态结合为目标任务状态,以其对应的任务元作为研究对象会使复杂系统简单化,而基于栅格理论的管理网络也可以有效地管理不同层次不同类别的任务元.并且可以实时地监测多机器人协同工作系统任务元权重的变化情况.首先将栅格网络中每一层的目标元素对应为多机器人系统不同级别的工作任务;其次从顶层开始,逐一确定上层任务包含哪些下层任务;然后采用基于离差最大化的多属性决策方法确定任务元的权重概率,最后以一简单算例验证该管理方法的简单有效.     

基于云、网、边融合的边缘计算新方案:算力网络

边缘计算已经成为5G时代重要的创新型业务模式,尤其是其低时延特性,被认为是传统方案所不具备的,因此边缘计算能够提供更多的服务能力且具有更为广泛的应用场景。但边缘计算与处于中心位置的云计算之间的算力协同成为新的技术难题,即需要在边缘计算、云计算以及网络之间实现云网协同、云边协同,甚至边边协同,才能实现资源利用的最优化。在研究边缘计算算力分配和调度需求的基础上,提出了基于云、网、边深度融合的算力网络方案,并针对AI类应用给出了一个典型实施系统,该方案能够有效应对未来业务对计算、存储、网络甚至算法资源的多级部署以及在各级节点之间的灵活调度。     

Computing and bounding the first-order Marcum Q-function: a geometric approach

A geometric interpretation of the first-order Marcum Q-function, Q(a,b), is introduced as the probability that a complex, Gaussian random variable with real mean a, takes on values outside of a disk C_O,b of radius b centered at the origin O. This interpretation engenders a fruitful approach for deriving new representations and tight, upper and lower bounds on Q(a,b). The new representations obtained involve finite-range integrals with pure exponential integrands. They are shown to be simpler and more robust than their counterparts in the literature. The new bounds obtained include the generic exponential bounds which involve an arbitrarily large number of exponential functions, and the simple erfc bounds which involve just a few erfc functions, together with exponential functions in some cases. The new generic exponential bounds approach the exact value of Q(a,b) as the number of exponential terms involved increases. These generic exponential bounds evaluated with only two terms and the new simple erfc bounds are much tighter than the existing exponential bounds in most cases, especially when the arguments a and b are large. Thus, in many applications requiring further analytical manipulations of Q(a,b), these new bounds can lead to some closed-form results which are better than the results available so far.     

网格计算:现状与进展

归纳、总结了网格计算研究的目标、体系结构、关键技术以及研究进展。分析了网格计算研究存在的主要问题，指出了网格计算研究领域的总体发展趋势和研究方向。     

从云计算到海计算：论物联网的体系结构

基于对物联网概念的理解,文章介绍了物联网的特征,特别是其底层感知信息的时空特性和局部实时交互性,以及从对物理世界的感知、感知信息的传输和处理、对物理空间的反馈控制的开放式循环过程。基于云计算到海计算再到云海结合,从信息存储和处理的角度出发,文章探讨了物联网承载和处理巨海量信息的方式和结构,以及物联网体系结构需要考虑的问题,如开放性式循环结构和智能终端。     

网格计算--下一代Internet计算模式

网格计算已逐步成为高性能计算及基于Internet应用的重要研究领域。详细描述了网格基本体系结构,指出了网格研究需要跟踪的关键技术,并介绍了国内网格发展现状及发展网格的重大意义。     

Mobile Computing Systems Programming: A Graduate Distributed Computing Course

Mobile devices are ubiquitous: they encompass portable audio and video players, digital cameras, tablet PCs and PDAs, as well as cell phones and smart phones. A Sept. 2006 Cellular News story (http://www.cellular-news.com/story/19223.php) estimated that there are more than 2.5 billion mobile phones worldwide. Although the mobile systems market is large and the career opportunities for students are excellent, relatively few universities offer mobile computing courses, much less teach mobile systems programming. Because mobile networks are likely to drive computing for the foreseeable future, the University of Melbourne Computer Science and Software Engineering Department created a Master of Engineering in Distributed Computing degree program.The MEDC program educates graduate students in rapidly evolving key areas such as distributed computing, mobile computing, pervasive computing, and sensor networks. I teach CSSE 653: Mobile Computing Systems Programming.     

云边端架构下边缘智能计算关键问题综述：计算优化与计算卸载

近年来,随着入网设备数量与数据体量的急剧增加,以云计算为代表的中心式计算模式的缺点越来越显露出来。边缘计算,即让计算尽量靠近数据源,以减少数据传输时间和网络延迟,作为云计算的补充,已经成为学术界和工业界关注的焦点。该文面向边缘计算中应用较广的实例架构—云边端架构,以及边缘计算的典型应用—边缘智能计算,讨论云边端架构下边缘智能计算的两大关键问题：计算优化和计算卸载。首先分析和梳理了云边端架构下边缘智能计算优化的应用与研究现状。然后讨论了云边端架构下计算卸载的研究思路和现状。最后,总结提出了目前云边端架构下边缘智能计算业务所面临的挑战和未来研究趋势。     

V氏图块状效应的消除

本文提出了一种消除Ｖ氏图块状效应的方法，它采用邻域像素交换通过视觉平均来达到平滑的效果，明显地改善了重建图像的质量。     

Computing the cosmos

This article describes an ambitious project which aims to simulate on a supercomputer the evolution of the entire universe from just after the Big Bang until the present. An international group of scientists, dubbed the Virgo Consortium, is creating the largest and most detailed computer model of the universe ever made. While other groups have simulated chunks of the cosmos, the Virgo simulation is going for the real thing. The cosmologists' best theories about the universe's matter distribution and galaxy formation becomes equations, numbers, variables, and other parameters in simulations running on one of Germany's most powerful supercomputers, an IBM Unix cluster at the Max Planck Society's Computing Center in Garching, near Munich.     

基于云计算平台的图书馆构建

云计算平台具有强大的数据处理、存储以及网络服务功能,可对数据进行有效管理。目前大多数图书馆已实现了由传统图书馆向数字化图书馆的转型。但与此同时,图书馆的数据存储也面临诸如安全、访问空间、速度及管理等方面问题。为图书馆构建适合的云计算平台是解决上述问题的有效途径。     

On the behavior of Bi in a CdTe lattice and the compensation effect in CdTe:Bi

CdTe crystals of two types have been grown by the vertical Bridgman method: (i) crystals doped with Bi to ～10¹⁸ cm^?3 and (ii) double-doped (Bi + Cl) crystals with a Bi concentration of ～10¹⁸ cm^?3 and a Cl concentration of ～10¹⁷ cm^?3. The temperature dependences of the resistivity, photoconductivity, and low-temperature photoluminescence are investigated for the crystals grown. Analysis has shown that doping with Bi (crystals of the first type) leads to compensation of the material. The resistivity of the CdTe:Bi samples at room temperature, depending on the doping level, is varied in the range of 10⁵–10⁹ Ω cm. The hole concentration is determined by the acceptor level at E _v + 0.4 eV in lightly doped CdTe:Bi samples and by the deep center at E _v + 0.72 eV in heavily doped CdTe:Bi samples. Double doping leads to inversion of the conductivity type and reduces the resistivity to ～1 Ω cm. Heavily doped CdTe:Bi crystals and double-doped crystals exhibit the presence of acceptors with an ionization energy of 36 meV, which is atypical of CdTe.     

Dynamic Leveling: Adaptive Data Broadcasting in a Mobile Computing Environment

The research issue of broadcasting has attracted a considerable amount of attention in a mobile computing system. By utilizing broadcast channels, a server is able to continuously and repeatedly broadcast data to mobile users. From these broadcast channels, mobile users obtain the data of interest efficiently and only need to wait for the required data to be present on the broadcast channel. Given the access frequencies of data items, one can design proper data allocation in the broadcast channels to reduce the average expected delay of data items. In practice, the data access frequencies may vary with time. We explore in this paper the problem of adjusting broadcast programs to effectively respond to the changes of data access frequencies, and develop an efficient algorithm DL to address this problem. Performance of algorithm DL is analyzed and a system simulator is developed to validate our results. Sensitivity analysis on several parameters, including the number of data items, the number of broadcast disks, and the variation of access frequencies, is conducted. It is shown by our results that the broadcast programs adjusted by algorithm DL are of very high quality and are in fact very close to the optimal ones.     

Voronoi在无线网络规划中的应用

简要介绍了Voronoi图的基本概念,详细论述了Voronoi图在无线网络规划中的具体应用及通过Map Basic编程实现小区级Voronoi图的算法,并给出了主要程序代码。     

基于通用计算的GPU-CPU协作计算模式研究

依据GPU计算特点和任务划分的特点,提出一种类似主从模型的GPU-CPU协作计算的处理模式,通过把问题或算法划分成多子任务,并对划分的子任务给出合理的调度算法,使GPU和CPU各自发挥特点,从而发挥较高效率的GPU通用计算能力,通过测试验证该协作模式是有效的.     

Ray propagation in a random lattice: a maximum entropy, anomalous diffusion Process

The typical model for diffusion in disordered systems is that of a random walk that proceeds in discrete steps over a random lattice, where not all the nearest sites can be reached at each step. We study the related problem of ray propagation in percolating lattices, and observe that it follows an anomalous diffusion process, whose appropriate metric is the "Manhattan" distance defined by the lattice geometry. The proposed solution is the one that exhibits the maximum Shannon's entropy, among all propagation processes with appropriate moment constraints imposed by the geometry of the lattice. Ray propagation in percolating lattices has been recently proposed as a model for urban area propagation of radio waves. We discuss implications of our results in this scenario.     

Construction of the Voronoi diagram for `one million' generators insingle-precision arithmetic

A numerically stable algorithm for constructing Voronoi diagrams in the plane is presented. In this algorithm higher priority is placed on the topological structure than on numerical values, so that, however large the numerical errors, the algorithm will never come across topological inconsistency and thus can always complete its task. The behavior of the algorithm is shown with examples, including one for as many as 10⁶ generators