eInvoke: Secure e-Invoicing based on web services

Electronic Invoicing services (e-Invoicing) will have a pivotal role in all the stages of handling Value Added Tax (VAT) for European Member States. Through a systematic introduction of e-invoicing, tax administrators will be able to implement new tools and procedures to carry out alternative controls that are less intrusive on the trading partners. Nevertheless, successful European e-invoicing implementations need to be in compliance with the corresponding European Directive 2001/115/EC. Most contemporary e-Invoicing implementations are proprietary and based on EDI, thus demonstrating great deficiencies. This paper presents an open electronic invoicing system named eInvoke, based on XML, XML cryptography and Web Services, that addresses all security requirements imposed by the Directive. Our e-Invoicing system has been accepted by “CEN/ISSS e-Invoicing Focus Group on Standards and Developments on electronic invoicing relating to VAT Directive 2001/115/EC” and its summary appears in CEN 2003 report [13] (pg 79–85), forwarded to EC as a recommendation. Alexandros Kaliontzoglou holds a Degree in Electrical and Computer Engineering from the National Technical University of Athens (NTUA), Greece. Since 2001 he is a PhD candidate in the area of Network and Information Systems Security at the Telecommunications laboratory in the School of Electrical and Computer Engineering of NTUA. Since April 2000 he has been working for Expertnet S.A. as a security engineer specializing at Web Technologies and network applications, and he has been active both in European research projects in the 5th and 6th Framework Programme (eMayor, Intelcities, SELIS, Reshen, La Mer, TSEC, WebSig) and projects of the Greek private sector. His research interests focus in the area of IT Security, Service Oriented Architectures, Web Services, Software Engineering, e-Government, e-Commerce and Public Key Infrastructures. Pelagia Boutsi has obtained the Degree in Informatics from the University of Piraeus, Greece, in November 2001. Since April 2002, she is a PhD candidate in the area of Security Information at the Computer Science Department of University of Piraeus. Since September 2001 she is employed at Expertnet S.A. as member of the Technical Department. Her current research interests are in the fields of PKIs, XML and XML Security. She has participated in European research projects and projects of the private sector. Despina Polemi has obtained the Degree in Applied Mathematics from Portland State University(USA) in 1984, Ph.D. in Applied Mathematics (Coding Theory) from City University of New York (Graduate Center) in 1991. She held teaching positions (1984– 1995) in Queens College and Baruch College of City University of NewYork. From 1991 to 1996 was assistant professor (tenure track) in State University of New Yorkat Farmingdale in the department of Mathematics. During 1996–2002 she was an associate researcher in ICCS. From 2000 to 2003 she acted as President of the BoD in a security consulting company Expertnet (www.expertnet.net.gr) and technical manager of the company from 2000–2004. She nowa Professor in the University of Piraeus R&D department. Her current research interests are in the fields of cryptology, security and e-business. She has over ninety publications in the above areas. She has received many research grants from various organizations such as the Danish Research Foundation, MSI Army Research Office/Cornell University, IEEE, State University of New York (SUNY), and The Graduate School of City University of New York (CUNY). She has been project manager (PM)/technical manger (TM) in security projects of various programmes such as National Security Agency (NSA), Dr. Nuala McGann Drescher Foundation, Greek Ministry of Defense, INFOSEC TELEMATICS for Administrations (COSACC), the Fifth Framework IST Programme (HARP, BEE, SEED, WebSig, TSEC, CORAS, RESHEN, SEED, La Mer, SECRETS) and the 6FP (e-Mayor, Intelcities, BIOSEC, SELIS). She participated in the EC security projects of the programs COST, ACTS, and NATOs’ security projects. She is a member of IEEE. She serves as an evaluator, reviewer and expert in the European Commission and consultant for the FP6.     

Agent-based game-theoretic model for collaborative web services: Decision making analysis

In agent and (web) service computing, collaboration takes place when distributed entities have limited knowledge and capabilities, so they cannot perform required tasks without interacting and helping each other. For instance, web services, which are loosely-coupled business applications, are called to cooperate in distributed settings for the sake of efficiency. In this context, agents that abstract and act on behalf of web services could act in cooperative groups that gather a number of agents sharing some common goals. Enabling those agent-based web services to decide about their strategies in terms of joining and acting within groups, inviting other agents to join, and leaving a group to act alone is an open issue that we address in this work. In this paper, we propose a framework where agent-based web services select strategies that maximize their outcomes. These strategies could be categorized into cooperative strategies involving other agents and strategies that highlight the single operative attitude. Although cooperation seems to bring better utility to cooperative agents, we highlight that web services in some environments obtain better outcome while they act individually (i.e., outside the group). This means that the cost of cooperation (in some particular cases) might negatively influence the outcome and obtained utility. As solution, we propose in this paper (1) an agent-based model that formalizes web services decision making where different parameters are considered; and (2) a game-theoretic framework that analyzes the web services strategies allowing them to maximize their acting performance where non-zero-sum games are being used. The paper presents theoretical results, which are also confirmed through extensive simulations.     

A web based collaborative testing environment

This paper presents a computer supported collaborative testing system built upon the Siette web-based assessment environment. The application poses the same set of questions to a group of students. Each student in the group should answer the same question twice. An initial response is given individually, without knowing the answers of others. Then the system provides some tools to show the other partners' responses, to support distance collaboration. Finally a second individual answer is requested. In this way assessment and collaboration activities are interlaced. At the end of a collaborative testing session, each student will have two scores: the initial score and the final score. Three sets of experiments have been carried out: (1) a set of experiments designed to evaluate and fine tune the application, improve usability, and to collect users' feelings and opinions about the system; (2) a second set of experiments to analyze the impact of collaboration in test results, comparing individual and group performance, and analyzing the factors that correlate to those results; and (3) a set of experiments designed to measure individual short-term learning directly related to the collaborative testing activity. We study whether the use of the system is associated with actual learning, and whether this learning is directly related to collaboration between students. Our studies confirm previous results and provide the following evidence (1) the performance increase is directly related to the access to other partners' answers; (2) a student tends to reach a common answer in most cases; and (3) the consensus is highly correlated with the correct response. Moreover, we have found evidence indicating that most of the students really do learn from collaborative testing. High-performing students improve by self-reflection, regardless the composition of the group, but low-performing students need to be in a group with higher-performing students in order to improve.     

基于C#的无IIS的Web Services服务

随着面向服务设计思想的进一步成熟,许多产品都提供Web服务,大部分的服务都依赖于第三方的程序,例如IIS,Apache等,而这些程序配置复杂,难以管理和维护.为避免这些问题,提出基于.NET、无IIS的Web服务的理论分析,并详细介绍了设计和实现的过程,实现了不需要任何配置和管理,即零配置和管理,不必依赖其它的Web服务提供者,便于程序的维护和发布.尤其是对于大量采用Web服务通讯的分布式程序,效率有很大的提高.     

基于Web Services的图像处理系统

随着分布式应用的普及,Web Services作为一项新兴技术具有很好的发展前景。本论文首先介绍了Web Services的体系结构;随后通过一个图像缩放处理应用详细描述了构建Web Services的步骤和方法,并通过WSDL文件实现服务器端和客户端的信息交互。最后通过建立UDDI注册中心,完成Web Services的动态注册、发现和绑定,并有效地实现分布式环境下的资源共享和协同工作。     

一种基于Web服务的工作流标识语言

在Web服务流标识语言WSFL的基础上,提出了一种在Web方式下基于Web服务的工作流标识语言WXML,解决了在Web方式下调用Web服务出现的“循环调用”问题,并对WXML工作流引擎进行了初步设计和实现。这种基于Web服务的工作流应用系统在互操作、集成、共享和效率等方面比现有技术具有明显的优势。     

基于REST Web Services的分布式遥感数据检索技术研究

为了更好地解决分布式遥感数据检索的问题,提出了基于REST Web Services的分布式检索实现方法.根据分布式数据检索的需求和遥感数据检索系统的特点,研究了分布式数据检索的实现技术、REST的基本概念、目标与设计原则、主要思想以及实现方式,在此基本上设计了基于REST Web Services分布式遥感数据检索原型系统,并实现了基于REST Web Services分布式遥感数据检索原型系统.     

语义网中基于Web资源本体的数据中介服务

为了搜索Web资源中深层数据并对其利用,在分析利用搜索引擎获取Web资源存在问题的基础上,利用语义网和Web服务技术,提出构建Web资源本体模型实现对Web资源进行语义标识,结合服务管理代理构建数据中介服务应用模型,并以Web服务方式实现Web资源数据中介服务.通过实验验证了Web资源数据中介服务的有效性和可行性,从而实现帮助用户能在形式多样、种类繁多的海量Web资源中有效地荻取和共享Web资源数据.     

基于Web Services的GDSS框架的研究

分析了群体决策支持系统(GDSS)和Web Services的技术特点。现有的GDSS存在许多缺陷,不能充分利用已有的各种资源,开发周期长,系统结构不灵活。Web Services是一套基于Web的分布式对象技术的标准。针对已有的GDSS的局限性,通过将Web Services技术与GDSS相结合,提出了一个基于Web Services的GDSS框架。利用此框架可以方便地实现网络资源的整合和组件重用,快速、高效地开发出实用的GDSS。     

基于协同过滤的Web缓存替换算法研究

针对GDSF替换算法中对访问频率缺少预测的不足,提出了一种基于协同过滤的GDSF缓存替换算法(GDSF-CF)。该算法考虑了Web对象之间相似性与用户访问时间间隔,运用协同过滤算法生成Web对象的预测访问频率,并采用齐普夫定律参数对GDSF算法的目标函数进行了改进。当需要进行缓存替换时,利用目标函数价值计算缓存空间中的每个Web对象缓存价值,将最小缓存价值的Web对象进行替换。仿真实验结果表明,该算法的命中率HR和字节命中率BHR都有较大提升。     

Meta web service: building web-based open decision support system based on web services

Web services are currently one of the trends in network-based business services, which intuitively will be applied to build a semantic web-based decision support system (DSS). Since web services are self-contained, modular business process applications, based on open standards, enable integration models for facilitating program-to-program interactions. Decision modules in a semantic web-based DSS can be viewed as a web service. However, according to the current features, web services know only about themselves, they are neither autonomous, nor are they designed to use ontologies; they are passive until invoked, and they do not provide for composing functionalities. These lead to the motivation on building a sophisticated web service to contain these features and to utilize web services on behalf of the user. This paper aims to propose a new concept of Meta Web Service, a web service-based DSS. The meta web service understands the user's problem statement with ontology, performs web service discovery, web service composition, and automatically generates codes for composite web service execution. Case-based reasoning is applied to quickly find past histories of successful service compositions. A prototype of research web service has been developed to show the feasibility of the proposed idea.     

基于Web Services的信息集成方案

随着网络技术的发展,信息的共享和交换显得越来越重要.针对目前网络中信息的异构性,多样性、分布性等特点,提出了一种基于Web Services的异构信息集成方案.该方案主要采用XML技术对各种源信息进行包装,形成了一个虚拟的数据库,从而实现了异构数据源的共享.然后将信息注册在信息注册中心,信息请求方获得XML格式的信息后,使用XML解析器对其解析.该方案有效地解决了"信息孤岛"问题.     

自适应贪婪算法在Web服务查询优化上的应用

在基于自适应技术的基础上,提出了一个Web服务查询优化模型(web service profiler-reoptimizer-cache,WSPRC).在其核心组件之一的Reoptimizer上采用自适应贪婪算法,分析了其执行Web服务查询优化的过程,并从Web服务有前向约束、无前向约束和信息变化等方面与传统的贪婪算法进行了对比.实验结果表明,WSPRC模型和A-Greedy算法提高了Web服务查询访问的效率,节省了查询成本.     

基于Web Services的分布式模型管理方法研究

在分析了基于Intranet模型管理系统国内外研究现状的基础上,提出了一种基于WebServices在分布式环境下用于决策支持系统的模型管理方法。该方法充分利用了最新的WebServices技术,使处于分布式环境下的模型可以进行模型的组合、生成和调用,为建立实用的分布式模型管理系统提供了一种可行的方法。     

构建基于Web Services的视频点播系统

在分析目前网上视频点播系统缺陷的基础上,提出了利用WebServices技术实现网上视频点播的思路,并介绍了视频点播的实现原理、实现方法和实现过程;简要分析了WebServices的工作原理,利用System,IO对象模型成功地在ASP.NET中实现了视频点播功能.     

基于Web服务的程序设计新思路

组件技术现已对国内外软件产业产生了深远的影响,然而原有的程序设计方法在业已存在的众多组件面前效率低下,产生了大量的资源浪费。提出的基于服务的程序设计（PBOS）就是一种充分利用分散的组件资源和硬件资源构建新型软件的方法,PBOS建立在以Web服务组件为代表的组件技术的松散性和异构性的特点之上,并充分考虑其零散分布性和组件的相对独立性,构建出一种跨域,甚至跨国进行组件搭建的基本方法,大大提高了组件资源和硬件资源的可重用性。     

基于MDA的Web服务动态组合的研究

针对目前Web服务动态组合方面出现的技术问题,给出了基于MDA的Web服务组合的方法,MDA具有将功能需求与具体实现技术分离的优势,因此可以有效地解决Web服务动态合成的可靠性、灵活性、复用性问题.在给出了结合MDA思想的服务合成体系框架的基础上,分析了UML类图与WSDL语言元模型、UML活动图与WS-BPEL语言元模型的对应关系以确定模型到代码的转换规则.最后以某制造企业的案例验证该技术的可行性.     

基于MTOM的Web服务性能优化研究

为提升Web服务性能,满足其进一步应用的要求,研究了消息传输优化机制(message transmission optimization mechanism,MTOM).针对基于Web的二进制数据传输,MTOM采用不同于传统内嵌Base64编码的方式,而是作为附件处理,压缩了报文,提高了性能.在理论分析的基础上,设计并构建了一组Web服务原型.通过一组对比实验,跟踪传输层报文验证了原型的正确和实际报文的缩减.实验结果表明了MTOM对Web服务性能近30％的提升.     

基于语义的Web服务发现方法的研究

传统的服务发现技术是建立在语法描述的基础上,主要采用的服务发现机制是WSDL和UDDI规范相结合的解决方案,这些发现方法查准率极其低下,已经不能很好的满足用户需要.在研究本体与语义web服务的基础上,提出了一种基于语义的web服务发现框架与服务发现算法,从而提高查准率.