Web服务组合中异构消息匹配模型研究

针对Web服务组合中异构消息匹配问题,以标准WSDL作为Web服务接口的描述语言,在建立共同领域本体的基础上,对Web服务接口信息进行语义扩展,通过本体匹配的方式提取Web服务接口XML Schema文档,将Web服务组合中异构消息匹配问题转化为XML Schema匹配,并应用XML Schema自动匹配算法及结合Web服务消息的特点,达到Web服务组合中异构消息自动匹配的目的.     

保障运行时适应性的web服务组合框架研究

在Web服务组合过程中,几乎每时每刻都有新的Web服务加入和退出,服务质量也处于动态变化中,本文分析了在Web服务组合过程中存在的问题,提出了保障运行时适应性的web服务组合框架,并给出了相应的服务替换算法和异构消息匹配算法,有效地解决了Web服务组合运行时的适应问题,并且通过扩展微软工作流框架实现了这一框架。     

基于消息机制的异构系统集成方案*

Web服务技术可以为异构系统集成提供有力支持,但在异步调用、流程控制和事务处理等方面仍然存在许多困难。提出了基于消息机制的异构系统集成方案,设计了总线型消息控制平台,通过基于XML的格式化消息提升系统集成的能力,并在数字化校园建设中得到了应用。     

Web服务交互测试中SOAP消息的控制和分析

由于Web服务的平台异构性，Web服务的交互测试是一个重要的测试方面。阐述了一种通过截获和分析通讯消息进行Web服务交互测试的方法。在这种测试模型中，SOAP消息的控制和分析是关键。详细论述了SOAP消息的控制和分析在测试中的作用，并在结尾给出了系统的设计实现。     

异构环境下语义Web服务发现研究

在语义Web服务组合涉及异构环境时,根据用户需求发现所需要的Web服务是一项关键的技术。本文以煤矿信息查询系统为应用背景,基于二分图最佳匹配算法提出了一种Web服务分级发现算法,通过计算异构环境中不同Web服务间的参数来完成不同服务的语义匹配,并讨论了分级发现算法的运行实例。     

基于XQuery扩展的异构语义Web服务发现

语义Web服务发现作为分布式计算的前提和关键,备受研究者关注。多种语义Web服务描述语言的存在给异构语义Web服务的发现带来了挑战。本文提出了一种支持异构语义Web服务描述语言的发现框架i XQuery。该框架从两个方面扩展XQuery,使其支持异构语义Web服务的结构化查询与逻辑推理、模糊匹配的联合查询。一方面i XQuery利用XQuery的外部函数机制,建立了多种类型的相似度比较函数;另一方面i XQuery制定了一个统一的语义Web服务抽象描述本体,并建立了语义Web服务语言SAWSDL与OWLS与该本体之间的映射,并利用XQuery的用户自定义函数机制,建立了一系列用于抽取异构语义Web服务中信息的抽象描述操作子。最后,介绍了基于i XQuery框架的异构语义Web服务匹配器H-i Matcher。     

一种基于DSL的服务组合语言

针对大规模并发应用在组合服务中的服务调度问题,设计一种基于领域专用语言的服务组合语言,给出该语言的主要功能、构造过程和语言执行引擎的详细设计。该语言提供对Web服务组合过程的语义和语法描述,采用自顶向下的组合方式,能解决Web服务组合过程中的组合粒度控制和异构消息匹配等问题。     

基于Web服务的异构工作流互联接口设计

为了实现企业间异构工作流系统的优势互补和信息共享,针对工作流呈现出的异构、分布等特点,提出了一种基于Web服务的异构工作流流程互联接口设计,以解决异构流程互联问题。从调用接口、调用方式、调用返回等三个方面描述了基于Web服务的流程互联解决方案;并以XPDL描述的SynchroFlow工作流流程与BPEL描述的ODE工作流流程为例,实现了这两种异构工作流的流程相互调用。     

An evaluation of image based steganography methods

Steganography is a process that involves hiding a message in an appropriate carrier for example an image or an audio file. The carrier can then be sent to a receiver without anyone else knowing that it contains a hidden message. This is a process, which can be used for example by civil rights organisations in repressive states to communicate their message to the outside world without their own government being aware of it. Less virtuously it can be used by terrorists to communicate with one another without anyone else’s knowledge. In both cases the objective is not to make it difficult to read the message as cryptography does, it is to hide the existence of the message in the first place possibly to protect the courier. The initial aim of this study was to investigate steganography and how it is implemented. Based on this work a number of common methods of steganography could then be implemented and evaluated. The strengths and weaknesses of the chosen methods can then be analysed. To provide a common frame of reference all of the steganography methods implemented and analysed used GIF images. Seven steganography methods were implemented. The methods were chosen for their different strengths in terms of resistance to different types of steganalysis or their ability to maximise the size of the message they could store. All of the methods used were based on the manipulation of the least significant bits of pixel values or the rearrangement of colours to create least significant bit or parity patterns, which correspond to the message being hidden.An erratum to this article can be found at     

基于OPNET的战术数据链系统时延仿真分析

以美军现役战术数据链为背景,分析了战术数据链系统的消息传输过程,归纳出4种消息传输方式;应用OPNET建立了战术数据链系统的网络模型、节点模型、进程模型,在此基础上实现了数据链系统仿真平台,仿真分析了系统内节点数量不同时,4种消息传输方式的消息时延和站点响应时间指标.仿真结果表明,上述指标受系统内站点数量及消息传输方式影响很大.作战过程中应依据作战需求合理确定站点数量,选择合适的消息传输方式,保证消息具有较好的时效性.最后指出了研究的意义.     

Windows的钩子技术及实现

使用钩子技术,应用程序可以监视指定窗口的某种消息.当截获到消息时,应用程序的钩子函数既可以加工处理该消息,也可以继续传递该消息,还可以强制结束消息的传递,因此,应用程序可以实现普通程序难以实现的功能.本文介绍了钩子的基本概念和类型,还介绍了钩子技术实现的方法,并给出了鼠标和键盘系统钩子的应用示例,为工程人员开发和使用钩子提供了一定的技术支持.     

微博消息传播中意见领袖影响力建模研究

在微博网络中,消息的传播与意见领袖的影响力密切相关.然而,意见领袖在消息动态传播过程中所表现出的影响力难以量化衡量,这对意见领袖影响力的评估和消息传播趋势的预测带来了巨大挑战.针对这一问题,提出一种基于消息传播的微博意见领袖影响力建模与测量分析方法.在分析消息传播模式的基础上,采用动态有向图描述消息在微博网络中的传播过程;发现该过程可近似分解为由各个意见领袖所驱动的子过程,根据对意见领袖影响力属性特征的分析发现,该子过程可以由指数截断的幂律衰减函数来描述.对模型中各个参数进行估计,可以定量地衡量意见领袖在消息传播过程中的初始影响力、影响力衰减指数及其影响力持续时间等指标.结合新浪微博数据的分析结果显示:消息的传播范围与传播过程中参与传播的意见领袖的数量呈弱相关;虽然意见领袖的初始影响力与其粉丝数量的大小正相关,但影响力衰减指数的大小以及影响力持续时间的长短与粉丝数量几乎无关.最后,采用所建模型对真实微博消息的传播趋势进行预测,结果表明,所提模型能够较好地对热门消息的传播趋势进行预测,这对微博中公众舆论的控制及广告定点投放具有重要意义.     

基于读写特征的总线分布式同步算法

为了解决分布式系统在总线网络中的读写同步问题,提出了基于读写特征的同步算法。该算法通过区分读写特征提高算法的并发度;通过哈希运算将分布式同步问题转化为单节点同步问题,提高了算法的性能,减少了所需的消息数;通过消息转发等方式,缩短了算法的响应延迟。性能分析和仿真试验表明,该算法有较低的消息复杂度和时间复杂度。     

在Visual C++ 中任意多个控件的创建

以在Visual C 中利用MFC机制创建任意个按钮为例，说明了在Visual C 实现任意个控件的创建。介绍在MFC机制下将多个同类控件的消息映射到同一处理函数的方法以及该机制下的消息映射过程，通过对MFC机制下的消息映射过程的分析，实现了任意多个按钮的消息处理。     

When does web-based personalization really work? The distinction between actual personalization and perceived personalization

A number of prior studies have suggested that personalization is more efficacious than non-personalization. However, the existing literature is somewhat ambiguous on whether the test of personalization effects should be based on a message sender's actual personalization process or a message recipient's perception of the message. It is argued in this article that an actual personalization process does not automatically yield more favorable effects because people's perceptions of personalized messages tend to be biased. Through three experiments, it is demonstrated that testing personalization effects based on a message sender's actual personalization process can be problematic and produce misleading results. Specifically, a personalized message can be perceived as non-personalized and a non-personalized message can be perceived as personalized. The key finding is that perceived personalization, instead of actual personalization, is the underlying psychological mechanism of message effectiveness. A message will show superior effects when it is perceived to be personalized by a message recipient, regardless of whether it is actually personalized or not.     

Windows线程、窗口与消息内在机制研究

以线程为核心,以消息为主线,剖析了Windows线程、窗口与消息三者之间的内在关系。线程是进程的执行实体;窗口由线程创建,并隶属于线程;通过消息机制,线程、窗口、消息构成了一个有机整体;窗口的一切行为都是由消息为之驱动的。行文同时指出了一些需要关注的问题。该技术主题对于Windows操作系统平台软件的设计、开发具有重要意义。     

Simple, Efficient Routing Schemes for All-Optical Networks

All-optical networks promise data transmission rates several orders of magnitude higher than current networks. The key to high transmission rates in these networks is to maintain the signal in optical form, thereby avoiding the prohibitive overhead of conversion to and from the electrical form, and to exploit the large bandwidth of optical fibers by sending many signals at different frequencies along the same optical link. Optical technology, however, is not as mature as electronic technology. Hence it is important to understand how efficiently simple routing elements can be used for all-optical communication. In this paper we consider two types of routing elements. Both types can move messages at different wavelengths to different directions. If in the first type a message wants to use an outgoing link that is already occupied by another message using the same wavelength, the arriving message is eliminated (and therefore has to be rerouted). The second type can evaluate priorities of messages. If more than one message wants to use the same wavelength at the same time, then the message with the highest priority wins. We prove nearly matching upper and lower bounds for the runtime of a simple and efficient protocol for both types of routing elements, and apply our results to meshes, butterflies, and node-symmetric networks. Received January 6, 1998, and in final form July 17, 1998.     

Asynchronous recovery without using vector timestamps

A checkpoint of a process involved in a distributed computation is said to be useful if it is part of a consistent global checkpoint. In this paper, we present a quasi-synchronous checkpointing algorithm that makes every checkpoint useful. We also present an efficient asynchronous recovery algorithm based on the checkpointing algorithm. The checkpointing algorithm allows the processes to take checkpoints asynchronously and also forces the processes to take additional checkpoints in order to make every checkpoint useful. The recovery algorithm can handle concurrent failure of multiple processes. The recovery algorithm has no domino effect and a failed process needs only to roll back to its latest checkpoint and request the other processes to roll back to a consistent checkpoint. Messages are only selectively logged to cope with various types of message abnormalities that arise due to rollback and hence results in low message logging overhead. Unlike some existing algorithms, our algorithm does not use vector timestamps for tracking dependency between checkpoints and hence results in low message overhead during failure-free operation. Moreover, a process can asynchronously decide garbage checkpoints and delete them from the stable storage—garbage checkpoints are the checkpoints that are no longer required for the purpose of recovery.