In Cognitive Radio Network (CRN),where Primary User (PU) and multiple Secondary Users (SUs) wish to communicate with their corresponding receivers simultaneously over fading channels,spectrum utilization and efficient resource allocation are both significant points for CRN.Interference between PU and SUs should be eliminated in order to realize spectrum sharing.Multi-user resource allocation with the target of maximizing the spectral efficiency of SUs and satisfying the proportional rate constraint between SUs are proposed under the conditions of total SU interference constraint.An adaptive low-complexity suboptimal algorithm for subcarrier and power joint allocation is presented based on Rate Adaptive (RA) criterion,where adaptive subcarrier allocation is performed by assuming equal power distribution,while each subcarrier is assigned in accordance with subcarrier efficiency function.Moreover,linear water-filling algorithm for power allocation is applied within each subcarrier.Simulation results indicate that,with the proposed adaptive subcarrier allocation,spectral efficiency of multiple SUs is superior to traditional subcarrier power joint allocation algorithm.Low computational complexity and adaptive features make it available for implementation.

关键词：认知无线电网络;自适应子载波分配;衰落信道;子载波效率

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One of the long-term goals of this project is to analyze and propose energy-efficient communication techniques for underwater acoustic sensor networks. These techniques aim at consuming as less energy as possible as well as guaranteeing a minimum quality of service. In order to do so, we assume and validate some statistics of the underwater acoustic channels and derive stochastic optimal transmission policies. Another long-term goal of this project is to investigate the possibility that these underwater acoustic networks disrupt the behavior of surrounding species of marine mammals. As a consequence of these two studies, we aim at developing minimally disruptive communication schemes.

关键词：海洋;随机过程;水下声学;水下通信

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Parallel algorithms for sparse matrix-matrix multiplication typically spend most of their time on inter-processor communication rather than on computation, and hardware trends predict the relative cost of communication will only increase. Thus, sparse matrix multiplication algorithms must minimize communication costs in order to scale to large processor counts. In this paper, we consider multiplying sparse matrices corresponding to Erdos-Renyi random graphs on distributed-memory parallel machines. We prove a new lower bound on the expected communication cost for a wide class of algorithms. Our analysis of existing algorithms shows that, while some are optimal for a limited range of matrix density and number of processors, none is optimal in general. We obtain two new parallel algorithms and prove that they match the expected communication cost lower bound, and hence they are optimal.

关键词：算法;乘法;稀疏矩阵;通信

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The current focus of ACAWS is on the needs of the flight controllers. The onboard crew in low-Earth orbit has some of those same needs.

关键词：飞行控制;预警系统;故障;系统健康监测;

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This thesis explores a novel network design concept to address the data and communications needs of the Department of Defense (DoD). Current and future military operations are increasingly reliant upon data connectivity to facilitate situational awareness and distribute vital information. Current infrastructures are insufficient to meet the growing demand, especially in the myriad austere environments where military forces operate. The DoD has become reliant upon increasingly vulnerable and expensive satellite communications to fill those gaps. The wireless data technologies utilized in the commercial sector to meet the data distribution requirements of business and commercial telecommunications providers can be leveraged and adapted to meet the connectivity requirements of the DoD. By pairing these technologies with developing HAPs and their capabilities the potential for a long-range wireless broadband solution emerges. This thesis evaluates broadband wireless data technologies in combination with High Altitude Platform (HAP) technologies. It proposes a network design concept to serve as a model for future research and the ultimate integration of HAPs into battlefield information architectures bringing the concepts of network centric warfare ever closer to reality.

关键词：无线计算机网络；宽带；通信和广播系统；数据处理;

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This research grant provided the opportunity to research and deploy beneficial transportation technologies to support transit needs. Working with the Transit Authority of Northern Kentucky (TANK), solutions were developed that can apply to transit agencies and emergency management across the country. As a result of this research, technologies were developed and deployed to Wi-Fi-enable buses, send video content to buses in transit, send riders service alerts via email and text, visualize the cost and environmental advantages of public transit, and provide location aware trip planning and other informational services via the Web, desktop gadgets, mobile apps, text messages, and kiosks.

关键词：信息系统;公共交通;物流;安全;公交车;电子信箱;应急管理;

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Consider a network of n processes each of which has a d-dimensional vector of reals as its input. Each process can communicate directly with all the processes in the system thus the communication network is a complete graph. All the communication channels are reliable and FIFO (first-in-first-out). The problem of Byzantine vector consensus (BVC) requires agreement on a d- dimensional vector that is in the convex hull of the d-dimensional input vectors at the non-faulty processes. We obtain the following results for Byzantine vector consensus in complete graphs while tolerating up to f Byzantine failures: * We prove that in a synchronous system, n > or = max(3f+1; (d+1)f+1) is necessary and sufficient for achieving Byzantine vector consensus. * In an asynchronous system, it is known that exact consensus is impossible in presence of faulty processes. For an asynchronous system, we prove that n > or = (d+2)f+1 is necessary and sufficient to achieve approximate Byzantine vector consensus. Our sufficiency proofs are constructive. We show sufficiency by providing explicit algorithms that solve exact BVC in synchronous systems, and approximate BVC in asynchronous systems. We also obtain tight bounds on the number of processes for achieving BVC using algorithms that are restricted to a simpler communication pattern.

关键词：拜占庭矢量共识;分布式计算;图;网络;矢量分析

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The vehicle terminal is part of the vehicle monitoring system,this article introduces ARM 9 and Bei Dou navigation and communication system which consisting of vehicle terminal system,which offers a method not only could combines Bei Dou communication,GPRS communication,Ethernet communication but also provides the multi-channel data acquisition,this method could ensure that the information transmission in the abnormal situations,and also could give full play to a variety of channels,use of resources,improve efficiency,reduce communication costs,and has great application prospects.

关键词：车载终端;多通道;斗;基于ARM9;在GPRS

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High performance for numerical linear algebra often comes at the expense of stability. Computing the LU decomposition of a matrix via Gaussian Elimination can be organized so that the computation involves regular and efficient data access. However, maintaining numerical stability via partial pivoting involves row interchanges that lead to inefficient data access patterns. To optimize communication efficiency throughout the memory hierarchy we confront two seemingly contradictory requirements: partial pivoting is efficient with column-major layout, whereas a recursive layout is optimal for the rest of the computation. We resolve this by introducing a shape morphing procedure that dynamically matches the layout to the computation throughout the algorithm, and show that Gaussian Elimination with partial pivoting can be performed in a communication efficient and cache-oblivious way. Our technique extends to QR decomposition, where computing Householder vectors prefers a different data layout than the rest of the computation.

关键词：算法;高斯消元法;线性代数;数值分析;通信

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The Federal Communications Commission (FCC) has established buildout requirements-which require a licensee to build the necessary infrastructure and put the assigned spectrum to use within a set amount of time-for most wireless services, including cellular and personal communication services. FCC tailors the buildout requirements it sets for a wireless service based on the physical characteristics of the relevant spectrum and comments of stakeholders, among other factors. Therefore, buildout requirements vary across wireless services. For example, a buildout requirement can set the percentage of a license's population or geographic area that must be covered by service or can describe the required level of service in narrative terms rather than numeric benchmarks. Buildout requirements also vary by how much time a licensee has to meet a requirement and whether it has to meet one requirement or multiple requirements in stages. FCC's enforcement process for wireless-service licenses with buildout requirements primarily relies on information provided by licensees, and FCC followed its process for the five wireless services GAO reviewed. Specifically, FCC requires licensees to self-certify that they have met buildout requirements. If a licensee does not do so, FCC automatically terminates the license. Some stakeholders GAO interviewed said that self-certification is an effective way for FCC to enforce buildout requirements because it is public and transparent. GAO examined FCC license data for five wireless services and found that buildout requirements were met for 75 percent of those licenses, and FCC generally terminated those that did not. As part of enforcement, FCC also grants or dismisses licensees' requests to extend the deadline for meeting a requirement. FCC may grant an extension if the licensee shows that it cannot meet a deadline due to causes beyond its control, like a lack of available equipment. For the five wireless services examined, GAO found that extensions were requested for 9 percent of licenses, and FCC granted 74 percent of these requests. FCC officials said that the Commission seeks to be aggressive but pragmatic when enforcing buildout requirements, including being flexible on deadlines when needed. Some licensees and industry associations GAO interviewed said that extensions can provide needed flexibility when unexpected problems occur. Some concerns were raised, however, that granting extensions can undermine buildout requirements by creating an impression that they will not be strictly enforced.

关键词：数据收集;通信;战略规划;电信;电信业

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