激光探测舰船尾流气泡样机初步实验研究

基于激光水下探测原理,采用自主研发的激光探测舰船尾流气泡样机,同时用气泡幕模拟舰船尾流,通过比较无气泡和有气泡两种条件下的样机接收信号,验证了样机的探测性能;并对气泡幕置于不同位置处的样机接收信号进行了分析和比较,研究了不同条件下回波信号的波形特点;最后对下一步的实验提出了几点建议。     

IPsec隧道终点发现技术研究

通过对目前常见的IPsec隧道终点发现技术的综述，分析了它们的优缺点和相应的应用场合，并给出了相应的改进方向。吸收相关发现技术的优点，并结合P2P网络的DHT搜索路由技术，提出了一种基于DHT的隧道终端安全发现技术，该技术具有可靠、安全、可扩展等特点，可适用于大规模VPN网络。     

下一代网络的业务模型和提供技术

文章在简要叙述业务驱动网络发展趋势的基础上,介绍了基于价值链的NGN业务商业模型和基于开放式分布计算的业务模型,详细分析了NGN的主要业务提供技术,并就NGN进一步的研究方向提出了看法.     

A Secure Infrastructure for Service Discovery and Access in Pervasive Computing

Security is paramount to the success of pervasive computing environments. The system presented in this paper provides a communications and security infrastructure that goes far in advancing the goal of anywhere-anytime computing. Our work securely enables clients to access and utilize services in heterogeneous networks. We provide a service registration and discovery mechanism implemented through a hierarchy of service management. The system is built upon a simplified Public Key Infrastructure that provides for authentication, non-repudiation, anti-playback, and access control. Smartcards are used as secure containers for digital certificates. The system is implemented in Java and we use Extensible Markup Language as the sole medium for communications and data exchange. Currently, we are solely dependent on a base set of access rights for our distributed trust model however, we are expanding the model to include the delegation of rights based upon a predefined policy. In our proposed expansion, instead of exclusively relying on predefined access rights, we have developed a flexible representation of trust information, in Prolog, that can model permissions, obligations, entitlements, and prohibitions. In this paper, we present the implementation of our system and describe the modifications to the design that are required to further enhance distributed trust. Our implementation is applicable to any distributed service infrastructure, whether the infrastructure is wired, mobile, or ad hoc.     

Supporting Service Discovery,Querying and Interaction in Ubiquitous Computing Environments

In this paper, we contend that ubiquitous computing environments will be highly heterogeneous, service rich domains. Moreover, future applications will consequently be required to interact with multiple, specialised service location and interaction protocols simultaneously. We argue that existing service discovery techniques do not provide sufficient support to address the challenges of building applications targeted to these emerging environments.This paper makes a number of contributions. Firstly, using a set of short ubiquitous computing scenarios we identify several key limitations of existing service discovery approaches that reduce their ability to support ubiquitous computing applications. Secondly, we present a detailed analysis of requirements for providing effective support in this domain. Thirdly, we provide the design of a simple extensible meta-service discovery architecture that uses database techniques to unify service discovery protocols and addresses several of our key requirements. Lastly, we examine the lessons learnt through the development of a prototype implementation of our architecture.     

9-ZENIC： A Scalable Distributed SDN Controller Architecture

In a software-defined network,a powerful central controller provides a flexible platform for defining network traffic through theuse of software.When SDN is used in a large-scale network,the logical central controller comprises multiple physical servers,andmultiple controllers must act as one to provide transparent control logic to network applications and devices.The challenge is tominimize the cost of network state distribution.To this end,we propose Distributed ZTE Elastic Network Intelligent Controller(D-ZENIC),a network-control platform that supports distributed deployment and linear scale-out.A dedicated component in the D-ZENIC controller provides a global view of the network topology as well as the distribution of host information.The evaluationshows that balance complexity with scalability,the network state distribution needs to be strictly classified.     

SOC设计的物理原型设计方法

本文介绍了一种数百万门SOC设计实现的方法，它基于在后端设计过程的前期创建一个物理原型，这个物理原型在传统的后端设计流程中某一阶段生成，与最终的设计具有很大的相关性，此物理原型可以成为许多设计实现方法优化的“桥梁”，它还改变了前端和后端的交接模型，在设计的早期就可参考物理信息，大大减少了迭代次数，层次化的设计方法也可以从优化物理原型的模块划分中获益。     

审计工作流原型系统的设计与实现

通过对大量日常审计业务工作的分析,总结出了多种相对稳定的审计流程模型,发现使用计算机的自动管理将较大地提高处理审计案例的效率。该系统采用工作流技术进行构建,提供了伸缩性较强的审计流程模型定义工具,有利于管理人员对审计流程的快速建模;使用了以组为管理单位的组织模型,灵活地进行审计人员的编组,以便于审计流程模型的引用。审计工作流原型系统的建立对工作流技术进一步在审计业务管理中的应用具有指导作用。     

数据链信息分发系统及其服务发现算法研究

针对现有数据链系统与指控系统间以格式化消息的方式进行交互,系统间耦合紧密,采用广播的方式分发信息,效率不高,与异构数据链系统间信息共享困难等问题,设计并给出了一种面向服务的数据链信息分发系统,详细描述了系统各单元的功能及协作方式。针对分布式环境下,数据链信息服务发现问题,结合现有服务发现的研究成果,分类分析了各算法应用时的优点与不足,在此基础上,给出了下一步研究方向。     

DDoS攻击的技术分析与防御策略

系统地分析分析了DDoS攻击的实现原理,列举了发动DDoS攻击的常用工具,针对攻击产生的机理,提出了详细可行的DDoS攻击防御策略.最后给出市场上典型DDoS攻击检测与响应系统的主要性能和防御DDoS攻击的研究方向.     

基于HLA通信网络仿真平台的研究

按照HLA体系结构设计和分析了通信网络仿真系统的仿真互联结构,针对通信网络系统的数据传输带宽的要求,以及数字和图像复合传输的特点,设计了通信网络仿真的系统结构。建立了仿真系统的SOM模型,基于RTI建立了通信网络仿真系统的测试环境。     

一种多处理器原型及其系统芯片设计方法

 随着嵌入式应用快速发展,系统芯片(SoC)设计日趋复杂.高效可靠的设计多处理器系统芯片逐渐成为一个巨大挑战.本文提出一种多处理器原型及其SoC设计方法,将多处理器及其通信统一建模于一个多层次、灵活和可配的软硬件原型中,通过分层次、从高层抽象到底层实现逐步深入的方法解决软硬件接口验证问题和完善软硬件架构.H.264解码实验证明多处理器原型功能可行性和物理可实现性.基于该原型的多层次细化方法可有效确保SoC软硬件设计的正确性,并有助于软硬件结构协同设计优化.     

一种CORBA／CMIP网关原型的实现

CORBA应用于网管的主要形式是和现有的网管系统互操作,这种互操作需要网关来进行CORBA与网管协议之间的转换。现详细介绍一个CORBA／CMIP网关原型的设计和实现。     

基于数字化样机的雷达目标跟踪技术仿真与验证

在机载火控雷达作战过程中,载机常常会根据作战需求做大幅机动,使目标相对于载机的运动变得复杂。在目标航迹滤波过程中引入载机惯导数据,可减小相对运动的不确定性,提高目标航迹估计精度和目标跟踪稳定性。雷达数字化样机是雷达物理样机功能和电性能在计算机内的一种映射。利用数字化样机的仿真测试环境可快速、全面、准确反映真实雷达功能、电性能等方面的特征和特性,数据处理的航迹跟踪性能评估均可以实时显示。文中利用数字化样机的参数级仿真测试功能对载机惯导补偿滤波算法进行仿真和验证。     

Service Discovery in Ad Hoc Networks: Performance Evaluation and QoS Enhancement

With the increasing popularity of wireless portable devices, such as laptops, PDAs and mobile phones, it is getting more and more important for mobile users to discover their required resources (e.g. printers and fax machines) without any need of configurations. To this end, automatic service discovery is an important feature of mobile Ad Hoc networks (Manets). In this paper a service discovery protocol for Manets based on the IETF Service Location Protocol has been implemented in the NS-2 simulator. Its performance is studied under different mobility patterns, network sizes and number of service agents. A lightweight quality of service (QoS) aware service discovery protocol is also proposed to support QoS applications. Zhong Fan is currently a Principal Researcher with Toshiba Research Europe in Bristol, UK. He received the B.S. and M.S. degrees in Electronic Engineering from Tsinghua University, China and the Ph.D. degree in Telecommunication Networks from Durham University, UK. His research interests are protocol design and performance analysis of wireless networks.     

MSC．ADAMS在贴片机动态精度研究中的应用

应用多体动力学方法模拟贴片机系统动态过程,仿真研究贴片机的动态精度问题。根据贴片机的结构形式,建立贴片机的数学模型和虚拟样机模型。用考虑结合部影响的刚柔耦合模型模拟实际系统,仿真分析影响贴片机动态精度的各种因素,根据分析结果建立优化模型,并对比分析原始模型与优化模型的动态精度。采用激光干涉仪对仿真分析结果进行试验验证．试验结果与仿真结果能较好地吻合,验证了该方法的正确性。     

贴片机数字化样机开发系统架构

根据贴片机涉及多个学科的特点,构建贴片机数字化样机开发系统,在设计的阶段采用多学科联合设计与仿真,对产品的功能与性能作校核与检验,通过协调各个系统的参数,使产品的性能达到设计指标;解决各个学科之间的冲突与干涉,使其达到最佳耦合。这将大幅度缩短产品开发周期,减少产品开发费用和成本,明显提高产品质量和系统性能。     

激光微细熔覆快速原型制备

传统上厚膜电容的制备由于采用了丝网技术、烧结工艺、有限的匹配温度特性材料,使得要实现高容量、低损耗、高频性就必须同时改变材料的成分、制备工艺和技术, 这是无法同时达到的.而采用激光微细熔覆快速原型制造技术,不需要高温烧结和掩模的制备,在不改变电极膜特性的情况下直接制备了适应高容量、低损耗和高频应用的介质膜.同时,消除了原有技术通过多次印刷和增加厚度来减少针孔的弊端,以及高温烧结带来的电极材料和介质材料成分的扩散,利用CAD/CAM系统可灵活地制备所设计的图形和尺寸,实现了元件小型化、轻薄化的制造.     

一种基于位置和DHT的移动ad hoc网络服务发现方案

移动ad hoc网络中要求各节点问在缺乏预备知识的情况下进行相互通讯和协作，因此，对网络中各种服务的自动发现成为了其中的一个关键问题。将各节点的位置信息和DHT技术结合起来．提出了一种高效的面向移动ad hoc网络的服务发现方案。首先直接基于网络的物理拓扑结构来构建一种分布式哈希表．从而有效地消除了现有DHT方案的拓扑结构不匹配问题。然后提出了一种维度映射的方案．以将多维的服务描述信息映射到二维的哈希键值空间上。最后提出一种区域搜索算法，以高效地支持对服务的条件查询。