该文提出了一种新的物理网络拓扑发现算法.该算法的基本思想是采用树的形式表示交换机拓扑连接关系.在此理论基础上利用生成树集合演绎树的变化过程来完成拓扑发现,并结合一种典型的交换机连接关系进行了算法推导.理论分析和实际应用结果表明,这种新的拓扑发现算法在发现效率、准确性、有效性等方面都有了很大程度的提高.

Traditional network measurement methods,such as uniform sampling and poisson sampling,deviate true data set a lot due to the self-similarity of the network traffic.This paper proposes a new network data measurement and statistics model based on real-time analysis (NMSM) which can be used to analyze the real-time changing characters of the data,adjust the sampling frequency dynamically,then fulfill the data sampling to the best advantage.The experiment showed that if the network environment changed smoothly the NMSM model seldom affected network;and if the network environment changed greatly it fitted the true data set very well.

Topology discovery of link layer is one of the difficulties of network measurement technology.Currently most of researches about topology discovery technology are based on the algorithm of connection relationship of switches which was proposed by the Yuri Breitbar from Bell Labs.This paper presents a new topology discovery algorithm of link layer which has better accuracy,discovery efficiency and effectiveness,meanwhile solves the issue of the mismatch between the device port and MAC address caused by VLAN.

The current Network Management System(NMS) has the following problems:lack of monitor and management of network flow;lack of value-added service function,such as security,counting and network optimization;not supporting the analysis of high layer network management businesses demanded by network administrators and high-level managers.This paper designs a new network flow analysis system(FlowMonitor) to promote NMS and to solve the deficiencies of the conventional NMS.Focusing on the high layer requirements in network management,FlowMonitor can satisfies users'demands for analysis of using status,security defense and counting model based on the network flow.

This paper first makes an intrduction of the flow and application of MD5 digital signature algorithm,then decribes in depth the implementation in hardware based on FPGA and holistic chart as well.

A novel text digital watermarking technology based on human psychological cognitive model is presented in this paper. Through changing the topology of a character or string, different structure figures are schemed out, which represent the same semanteme, and these figures should be correctly encoded. With this technology, digital watermarking information is embedded in different topology of a character or string. The text digital watermarking technology has the following advantages: great capacity of watermarking, strong robustness, little visual influence and quite good attack-resisting capability.

Pattren recognition is developing rapidly recently,this paper shows its concept and methods including digital image processing technology. Pattern recognition's application on digital display systems of apparatus is emphatically introduced.

Some limitations exist in the mobile middleware based on the Java RMI Technology. On the background of middleware, distributed object computing and mobile computing, the paper proposes an architecture of mobile middleware based on distributed object (MMDO), which is consist of the dynamically customizable base core, the general mobile agent platform, asynchronous message service, the distributed resource discovery service. MMDO can resolve the efficiency of Java in the mobile middleware, and extend the service of mobile middleware, which could provide the best support environment for mobile application. Lastly the paper gives the result of simulation test and proves the validity of the MMDO.

CORBA Event Service provide the communication capability of objects in the heterogeneous environment. This article conforms to the CORBA specification 2.4, presents an design of reliable event service based on classification, which could dispose the classified event in the process of the information transmision and assure the different events could be completed quickly and reliably in different application environment. Some important details of designing and implementation are also discussed in the dissertation.

文中提出了一种构件应用服务器模型,能够管理DLL形式的CORBA服务对象.这种方式能够对服务对象以构件形式进行管理,动态加入新的服务对象和停止原有服务对象,从而保证整个系统的连续运行.构件应用服务器的实现主要包括CAS管理器、服务对象、对象适配器三个部分.

An Integrated Product Development (IPD) method combined with the software Capacity Maturity Model (CMM) is presented. The key elements in the framework of IPD are explored, and the product development process under the framework is discussed. Aiming at the features of telecommunication product, the integration between IPD and CMM is studied. At last the deployment of IPD is addressed and some key issues are pointed out.The pilot projects proved that the IPD is an effective method for the telecommunication product development.

1 前言目前传统中间件在技术上已基本发展成熟,在国内外占有最大的市场份额.但传统中间件是一种以"过程"为基础的编程技术.新一代面向对象中间件在符合CORBA规范2.X的前提下,提出了一种"构件化"的思想,它保证不同产品相互之间能够实现互操作[1,2].为满足新的面向对象应用的需要,同时保持向前兼容传统中间件的应用,本文提出了一种全新的思路和实现,将消息中间件作为ORB的底层通信协议,即保持应用不变,"核心"向前推移,提供给用户一个高性能的分布式计算平台.

The limitations of traditional name services in constructing dependable systems are discussed in this paper, and TongCos, a reliable name service based on replication of nameservers and objects, is presented. TongCos Implements a consistency algorithm founded on VSC model. By introducing a loose binding mechanism between objects and name strings, TongCos guarantees a conspicuous enhancement of reliability without losing scalability in systems.

1引言 分布计算技术是指在网络计算平台上开发、部署、管理和维护以资源共享和协同工作为主要应用目标的分布式应用系统.OMG的CORBA(Common Object Request Broker Achi-tecture)标准支持对象异构平台的互操作和可移植,使分布式应用的开发更加方便、快捷.