基本初等函数的保密云计算服务协议

目前云计算已经成为解决很多问题的一个有力平台,同时也带来了大量的安全隐患。其中,关于基本初等函数的保密计算是所有云计算的基础和核心。 提出了所有基本初等函数的保密云计算服务协议,其基本思想是将原始数据做变换后,把计算复杂部分发给云平台,通过云计算将结果反馈给接受服务方,从而保密地计算相应函数。通过广泛接受的模拟范例证明了协议的安全性。协议中接受计算服务方可用很少的计算资源解决复杂的计算问题,保证了较低的计算复杂度和通信复杂度,因此提出的协议是有效可行的,可以成为云保密计算中的基础子协议。     

Signals,timers, and continuations for multithreaded user‐level protocols

Precise timing and asynchronous I/O are appealing features for many applications. Unix kernels provide such features on a per‐process basis, using signals to communicate asynchronous events to applications. Per‐process signals and timers are grossly inadequate for complex multithreaded applications that require per‐thread signals and timers that operate at finer granularity. To respond to this need, we present a scheme that integrates asynchronous (Unix) signals with user‐level threads, using the ARIADNE system as a platform. This is done with a view towards support for portable, multithreaded, and multiprotocol distributed applications, namely the CLAM (connectionless, lightweight, and multiway) communications library. In the same context, we propose the use of continuations as an efficient mechanism for reducing thread context‐switching and busy‐wait overheads in multithreaded protocols. Our proposal for integrating timers and signal‐handling mechanisms not only solves problems related to race conditions, but also offers an efficient and flexible interface for timing and signalling threads. Copyright © 2006 John Wiley & Sons, Ltd.     

VERICOMP: a system to compare and assess verified IVP solvers

Obtaining verified numerical solutions to initial value problems (IVPs) for ordinary differential equations (ODEs) is important in many application areas (e.g. biomechanics or automatic control). During the last decades, a number of solvers have been developed for this purpose. However, they are rarely used by industry engineers. One reason for this is the lack of information about what tool with what settings to choose. Therefore, it is necessary to develop a system for testing the available tools and recommending an ODE solver best suited for the task at hand in the area of verified software. In this paper, we present the first version of our web-based platform VERICOMP for assessing verified IVP solvers. We discuss a possible classification for user problems, suitable comparison criteria and measures for the quantification of overestimation. After that, we introduce the platform itself, which allows us to compare different solvers on a problem class or to evaluate the performance of a single solver on different problem classes. In addition, we describe how to extend VERICOMP with a recommender system that automatically suggests the most suitable solver based on user preferences and solver statistics.     

移动自组网的匿名路由协议研究综述

移动自组网中的恶意节点对路由协议的安全和隐匿具有严重威胁.现在针对安全路由协议的研究很多,但是很少有人涉及匿名性问题,匿名路由协议能够实现节点身份、位置和通信关系的隐匿,在军事和其它机密通信领域中具有重要意义.首先对匿名路由协议面临的攻击行为进行分析,介绍其定义、分类和匿名性评价方法,然后概括性的介绍已有的典型匿名路由协议,比较其匿名性和安全性,最后对以后研究的问题和方向作了总结和展望.     

A survey on routing techniques in underwater wireless sensor networks

Underwater Wireless Sensor Networks (UWSNs) are finding different applications for offshore exploration and ocean monitoring. In most of these applications, the network consists of significant number of sensor nodes deployed at different depths throughout the area of interest. The sensor nodes located at the sea bed cannot communicate directly with the nodes near the surface level; they require multi-hop communication assisted by appropriate routing scheme. However, this appropriateness depends not only on network resources and application requirements but also on environmental constraints. All these factors provide a platform where a resource-aware routing strategy plays a vital role to fulfill the different application requirements with dynamic environmental conditions. Realizing the fact, significant attention has been given to construct a reliable scheme, and many routing protocols have been proposed in order to provide an efficient route discovery between the sources and the sink. In this paper, we present a review and comparison of different algorithms, proposed recently in order to fulfill this requirement. The main purpose of this study is to address the issues like data forwarding, deployment and localization in UWSNs under different conditions. Later on, all of these are classified into different groups according to their characteristics and functionalities.     

安全协议的形式化分析方法研究

安全协议在网络信息安全中扮演着重要角色，但保证安全协议的正确是一个很困难的问题。现在，许多形式化方法都被用来分析安全协议，本文中我们研究各种方法的基本思想、它的优缺点、发展趋势以及方法之间的关系。最后，说明安全协议形式化分析的困难所在。     

基于自适应遗传算法的多传感器多目标静态数据关联

利用多传感器跟踪多目标技术中最重要的问题是目标关联问题,而常见的关联算法要私计算量大,要私实际动用中效果不理想。本语文提出了利用自适应遗传算法来解决在传感人、检测空域中目标个数未知情况下,单平台多传感器数据融合系统对目标进行检测时的静态数据关联问题。实验结果表明,这种算法具有很高的关联成功率,并且提高了多传感器数据融合系统的检测概率。     

基于密码协议认证目标的协议分析方法的研究

为了克服现有的逻辑方法不适合分析电子商务协议的缺点,本文提出了一种基于协议认证目标的协议分析方法,该方法针对不同功能的协议,给出了他们要实现的目标:实体认证目标、密钥认证目标和伴随有密钥建立的实体认证目标。在文章的最后我们通过分析Diffie-Hellman密钥建立协议验证了该方法的正确性和易用性。     

$3C6410平台多媒体播放器设计与实现

嵌入式多媒体播放器因其所依赖平台的硬件资源有限,尤其是CPU的工作效率低,造成了视频文件在播放时音视频不同步。实现嵌入式多媒体播放器开发的重点之一,就是要解决音视频同步问题。针对$3C6410平台下AVI格式视频播放分析了关键技术,提出音视频同步方案,实现了针对AVI格式的视频文件播放的多媒体播放器,并且可以在$3C6410平台上运行,得到了预期效果。     

Design and implementation of a QoS-aware MAC protocol for Wireless Multimedia Sensor Networks

Wireless Multimedia Sensor Networks (WMSNs) have entered the class of Wireless Sensor Networks (WSNs) to meet the multimedia requirements of new emerging applications, such as surveillance and telepresence. Combining the traditional scalar sensors used in WSN nodes with tiny cameras and microphones, WMSNs commonly carry heterogeneous traffic with different Quality of Service (QoS) requirements. In order to deliver heterogeneous traffic with different requirements in highly resource constrained sensor networks, QoS provisioning and service differentiation become unavoidable. In this paper first we discuss the QoS-provisioning in sensor networks and evaluate the efficiency of existing QoS-aware MAC protocols. As a result of this evaluation, next we design and implement a QoS-aware MAC protocol for WMSNs, Diff-MAC, which integrates different methods to meet the requirements of QoS provisioning to deliver heterogeneous traffic and provides a fair all-in-one QoS-aware MAC protocol. Diff-MAC aims to increase the utilization of the channel with effective service differentiation mechanisms while providing fair and fast delivery of the data. Performance evaluation results of Diff-MAC, obtained through extensive simulations, show significant improvements, in terms of latency, data delivery and energy efficiency, compared to two other existing protocols. Implementation of Diff-MAC on Imote2 platform also reveals that the protocol with moderate complexity can be easily implemented on the resource constrained motes.     

基于Swarm平台的理性密码协议建模与仿真

针对现实世界中理性密码协议的参与者博弈过程不易观察和预测的问题,文章在多智能主体的仿真平台Swarm上对理性密码协议中参与者的诚实策略和非诚实策略行为进行了建模和仿真。文章首先定义了主体的收益矩阵,进一步根据收益矩阵建立了参与者在整个博弈过程中的状态复制方程;然后求解出该方程的三个均衡点,即所有参与者分别采用诚实策略、非诚实策略和混合策略时的不同均衡点取值,根据这三个取值设计了协议执行过程中主体间的博弈算法;最后,文章在Swarm平台上定义了博弈主体所需要的各个对象。由于Swarm平台上的基本对象功能不能完全满足理性密码协议仿真的需要,文章改造了Swarm平台上部分主体对象功能,给出了改造的关键代码,对协议交互过程中的博弈行为进行了仿真。仿真的实验结果表明,Swarm仿真工具可以有效观察到参与者的理性选择过程;并通过调节博弈算法中的收益参数来达到预期效果,使博弈在较少的次数内达到博弈的稳定均衡,同时使得选择诚实策略的参与者占总人数的一半以上。文章提出在Swarm平台上进行理性密码协议仿真的方法,对使用计算方法研究理性密码协议具有一定的参考价值。     

On the decentralized coordination of herding activities: a Jadex-based solution

The AgentContest 2009 provided a revised Cows and Herders scenario which extended the last year’s setting. First, additional environment objects, i.e., fences and switches, were introduced. Secondly, the team score is calculated by the net amount of herded cows at the game end. In this paper we present the design of the multi-agent system (MAS) prototype which participated in this contest and has been developed under usage of the Jadex multi-agent platform. The main focus of our second-time participation was to switch from the centralized coordination architecture of our previous MAS to a decentralized coordination in order to increase the single agents’ autonomy. To facilitate the development parts of the Tropos methodology were utilized. These have been extended by platform specific features (e.g. the modularization concept). During the development we were able to identify and eliminate key problems and as a result our prototype could achieve the second place in the contest.     

Java动态类加载分析

动态类加载是Java的一个重要功能,它支持Java在运行时安装程序组件。Java的动态加载具有惰性加载、用户自定义加载策略以及动态名字空间等新特征。本文详细讨论了Java的动态加载机制,研究了动态加载与Java平台安全性之间的关系,分析了针对类加载的典型攻击,讨论了形式化验证的方法和存在的相应问题,最后总结全文并指出进一步研究的方向。     

基于CORBA规范的群件开发平台的研究

本文针对当前群件面临的问题,提出了群件组件化的思想,以及基于ＣＯＲＢＡ规范建立群件开发平台。     

电力企业大数据基础平台

电力企业各专业均有大数据应用需求,而大数据解决方案和产品路线众多.从一体化企业级信息系统的角度出发,需要构建统一平台,实现大数据应用服务平台化,全面支撑各专业大数据应用需求,避免重复建设.文章分析了电力企业大数据应用需求和技术现状,基于此提出了大数据基础平台的功能架构,最终对平台的设计思想和实现思路进行了详细论述.     

基于网格技术的电子商务平台研究

随着计算机技术尤其是网络技术的飞速发展以及全球经济一体化步伐的加快,电子商务得到了越来越广泛的应用.但是资源分布的不均衡性造成企业内部和外部存在大量的信息孤岛,严重制约了电子商务的进一步发展.本文主要分析了目前电子商务发展中存在的问题,探讨了网格技术对电子商务的影响,并给出了基于网格技术的电子商务平台模型的初步设计.     

Ad Hoc网络中隐藏终端和暴露终端相关问题研究

隐藏终端和暴露终端问题是Ad Hoc网络中的固有问题,成为影响网络性能的关键因素,是否较好解决了此类问题,已成为衡量MAC协议设计好坏的重要标准。文章在明确了隐藏终端和暴露终端的概念后,另定义了＂隐藏终端不同时发送＂和＂暴露终端被动为接收者＂两类问题,对MAC协议解决以上问题的方法进行了分类,剖析了各类方法的原理,并比较了其优劣,评价了其效果。     

分布式网络控制系统的研究

综述了网络控制系统的出现背景、概念和特性,阐明了网络的应用给传统控制系统带来的益处及广阔的应用前景,分析了网络传输数据给网络控制系统带来的问题,并阐述了网络控制系统中不同于一般网络系统的通信问题,详细分析了近年来迅速发展的现场总线和以太网在分布式网络控制系统中的发展趋势。最后概述了网络控制系统当前的研究现状。指出将网络通信调度和系统控制结合起来,将基于假设的理论研究同基于实际对象的实验平台相结合,是未来的发展趋势。     

基于P2P技术的云计算教育服务平台设计与实现

近年来,云计算已经成为网络服务领域中的研究热点。为了将云计算的理念服务于当前高等教育,提出设计一种基于P2P技术的云计算教育服务平台。首先介绍P2P技术和云计算的概念,然后提出一种云计算教育服务平台的设计框架,最后结合高等学校计算机专业课程的教学实践阐述如何实现一个在线测试的云计算教育服务平台。     

基于清华云监控平台的云迁移性能

当云计算技术兴起后,很多企业已经或计划将业务和应用迁移到云上,而这面临着应用性能可能降低,关键业务和应用安全性受到威胁等问题,因此是否云迁移还是部署到独立服务器上,是一个需要深入研究的问题.以清华云平台为基础,搭建了基于Nagios的清华云监控平台,先对清华云平台和架构进行介绍,再对Nagios和清华云监控平台架构进行了论述,在云迁移性能评估中,以Ubuntu和Windows为操作系统平台,以CPU负载和内存使用为评估指标,分别在云服务器和独立服务器上运行CPU运算类和服务器负载类两类应用,最后对实验结果进行了分析和比较.实验表明,部分应用在独立服务器上性能更好,并不适合云迁移.