WWW上路径模式发掘的研究

本文从互连网发展的趋势入手,对路径模式发掘进行了研究。先简要介绍数据库发掘的概况及网上数据发掘的特点,后结合关联法和组合概率法,并以算法和实例详细对之进行分析。     

Generalized non-recursive traversal of binary trees

A non-recursive algorithm for the traversal of a binary tree is presented in which the order of traversal is defined by an external data array, allowing any of the six possible orders to be selected without modification to the algorithm itself. The extra storage requirements are three pointer variables and two bits per node (or two bits per level if an auxiliary stack is used.) The algorithm is a generalization of the pointer reversal method of Schorr and Waite and is derived by transformation of a generalized recursive version. The algorithm is described using the notation and conventions of Pascal.     

Web应用系统跨多级防火墙访问企业数据资源的解决方案

分析了企业网的结构,针对防火墙在保障网络安全的同时严格限制外部访问的情况,提出了Web应用系统跨越多级防火墙访问企业数据资源的软件架构。以汽车站客运班次查询为例,基于轻量级JavaEE平台开发了采用该架构的应用系统,阐述了该解决方案的具体实现方法和步骤。并进一步分析了应用服务器,给出了提高应用服务器性能的若干方法。最后,对方案进行了评价,指出了该方案易于扩展、便于维护、灵活性高的特点。实践表明,该方案具有较好的推广应用价值。     

动态网络中多规则的最短路径查询算法

最佳排序路径查询,是智能交通中的热点问题.在实际的应用中,由于最佳排序路径查询有许多限制条件,现有的算法不能有效地解决动态网络中受限制的路径查询问题.为了解决动态网络中最佳排序路径查询问题,用规则表示每个限制条件,提出了一种新的最佳排序路径查询形式,即多规则的最短路径查询.提供了统一的框架,该框架包含了路径集合查询和最短路径查询.在路径集合查询部分,为了高效地查询出满足多规则的路径集合,在广义规则树的基础上,提出一种新的树的遍历方式,即树的继承全遍历;并基于树的继承全遍历思想,提出一种剪枝技术,对路径集合进行删减,最后求得候选路径集合.在最短路径查询部分,提出一种基于动态阈值的最短路径搜索方法.通过两个真实的动态道路网络的实验验证,所提出的算法能够高效地解决多规则的最短路径查询问题.     

基于P2PSIP的NAT穿透方法的研究

提出了一种基于P2PSIP的NAT穿透方法,可以在不同类型的NAT环境中,在不改变现有的NAT设备软件及其配置的情况下,解决两个私有网络IP电话终端的端对端通信问题.该方法通过适当扩展SIP协议,借助STUN协议以及RTP中继实现端对端的SIP信令和媒体流的建立,完成通信连接的建立与维持.     

概率逻辑神经元网络收敛性的分析

本文以马尔科夫链理论为工具,研究PLN(概率逻辑神经元)网络的定量性质.我们得到的主要结果是,在一给定网络中,给出各状态收敛到稳定状态的概率,平均收敛步数和方差以及一般PLN网络平均收敛步数的上(下)界估计.给出计算机的一个模拟结果,并与理论结论相对比,以验证理论结果的正确性.     

Semantic data modelling and visualisation using Noetica

Noetica is a tool for structuring knowledge about concepts and the relationships between them. It differs from typical information systems in that the knowledge it represents is abstract, highly connected, and includes meta-knowledge (knowledge about knowledge). Noetica represents knowledge using a strongly typed graph data model. By providing a rich type system it is possible to represent conceptual information using formalised structures. A class hierarchy provides a basic classification for all objects. This allows for a consistency of representation that is not often found in “free” semantic networks, and gives the ability to easily extend a knowledge model while retaining its semantics.

Visualisation and query tools are provided for this data model. Visualisation can be used to explore complete sets of link-classes, show paths while navigating through the database, or visualise the results of queries. Noetica supports goal-directed queries (a series of user-supplied goals that the system attempts to satisfy in sequence) and pathfinding queries (where the system finds relationships between objects in the database by following links).     

Deterministic parallel list ranking

In this paper we describe a simple parallel algorithm for list ranking. The algorithm is deterministic and runs inO(logn) time on an EREW PRAM withn/logn processors. The algorithm matches the performance of the Cole-Vishkin [CV3] algorithm but is simple and has reasonable constant factors.R. J. Anderson was supported by an NSF Presidential Young Investigator award and G. L. Miller was supported by NSF Grant DCR-85114961.     

基于代理机制的IPSec-NAT兼容性分析

VPN中要实现NAT的透明穿越,要解决的主要问题是如何实现IPSec和NAT的协同工作。文章在分析IPSec与NAT兼容性问题的基础上,讨论了现有几种解决方法,设计了一种基于代理机制的UDP封装方案。     

清洁机器人自主避障及遍历方法研究

分析了常见避障及遍历方法,对清洁机器人提出了一种基于坐标系的顺序逐次路径遍历规划方法,并提出了一种多种路径遍历方法结合新思路,为提高清洁机器人清洁效率和实现全覆盖遍历提供了支持。