Toward Behavioral Web Services Using Policies

Making Web services context-aware is a challenge. This is like making Web service expose appropriate behaviors in response to changes detected in the environment. Context awareness requires a review and extension of the current execution model of Web services. This paper discusses the seamless combination of context and policy to manage behaviors that Web services expose during composition and in response to changes in the environment. For this purpose, a four-layer approach is devised. These layers are denoted by policy, user, Web service, and resource. In this approach, behavior management and binding are subject to executing policies of types permission, obligation, restriction, and dispensation. A prototype that illustrates how context and policy are woven into Web services composition scenarios is presented as well.      

Personalised ubiquitous file access with XML Web Services

The explosion of new types of end-user devices, as well as the increase in the number of users with broadband connection in private households, opens up the opportunity to provide access to documents and services residing in the home domain from remote locations. Also, the increased mobility of users, as well as the need to be able to work in all locations, further adds to the requirement of remote document access. The contribution of this paper is threefold. First, it introduces the Mobile Home Access system, which simplifies remote access to resources in a home domain. The Mobile Home Access (MHA) system is based on the Service-Oriented Computing concept and realized using XML Web Services for communication between the home domain and the end-user device, while employing the Common Internet File System (CIFS) network file system to allow appropriate file access in the home domain. The second contribution is the mechanism whereby such a service can be deployed when network elements like firewalls and NAT routers are introduced. The challenge of establishing a connection from a remote device is general for both client–server services and peer-to-peer services. The paper proposes and describes a design and implementation of a solution using XML Web Services technologies, and thus shows how NAT traversal technology can be integrated with such middleware. The third contribution of this paper is a performance analysis of the current implementation of the Mobile Home Access service. The results of the analysis should be interesting for the applicability of XML Web Services in mobile computing in general.     

Enhancing mobile Web access using intelligent recommendations

Intelligent Web recommendations derived from frequent user Web-access patterns can help typical mobile users efficiently navigate standard Web sites. To facilitate mobile Web access, mobile clients' display resolution must gradually increase. Additionally, servers need a simple and elegant solution for displaying content effectively on mobile devices. We propose an implicit server-side approach using intelligent Web recommendations that can significantly enhance the mobile-browsing experience.     

一种Web服务模型的动态行为转换方法研究实现

随着业务流程的复杂性与日俱增,编排和协调Web服务的价值也日益被人们所认识。近年来,国内外一些研究机构和IT企业在关于模型驱动架构MDA在Web服务中的应用方面作了不同程度的研究,但仅仅集中于Web服务模型的静态结构转换。根据MDA的思想,在Web服务模型的转换中,使用动态行为的平台无关模型PIM来定义业务流程,并提供将PIM转换成平台相关模型PSM的方法。研究Web服务模型的动态行为转换,讲述用UML活动图定义业务流程,并提供一种如何从UML活动图转换成BPEL的方法。     

基于UML活动图的Web服务合成动态行为建模方法研究

描述了利用UML进行Web服务合成的建模方法,包括静态结构建模和动态行为建模两个方面,针对Web服务合成的动态行为建模部分,详细说明了利用UML活动图进行建模时需要注意的问题,如活动图的控制流模式与Web服务合成控制流模式的语义对应关系,所支持的数据模式,以及为了方便模型转换对活动图actions元素的概念扩展,给出了动态行为建模方法,并给出了基于OCL的转换规则以及UML活动图元素到BPEL4WS元素的映射关系,最后通过订单管理案例对所述方法进行验证,为Web服务合成提供了新的思路。     

Web services policies

In addition to the basic Web services architecture, various specifications already exist for adding security, reliable messaging, and transaction mechanisms to Web services messages. All of these include numerous options to let them meet various application requirements. Specifying option choices for Web services in basic communication areas such as security, reliable messaging, privacy, and transactions is the immediate goal underlying efforts to define Web services policies.     

Automated verification of access control policies using a SAT solver

Managing access control policies in modern computer systems can be challenging and error-prone. Combining multiple disparate access policies can introduce unintended consequences. In this paper, we present a formal model for specifying access to resources, a model that encompasses the semantics of the xacml access control language. From this model we define several ordering relations on access control policies that can be used to automatically verify properties of the policies. We present a tool for automatically verifying these properties by translating these ordering relations to Boolean satisfiability problems and then applying a sat solver. Our experimental results demonstrate that automated verification of xacml policies is feasible using this approach. This work is supported by NSF grants CCF-0614002 and CCF-0716095.     

Web Services

Web Services gelten als die Technologie, mit der in Zukunft Softwarekomponenten innerhalb einer Organisation und zwischen Organisationen integriert werden.     

Modeling Trust Negotiation for Web Services

As Web services become more widely adopted, developers must cope with the complexity of evolving trust negotiation policies spanning numerous autonomous services. The Trust-Serv framework uses a state-machine-based modeling approach that supports life-cycle policy management and automated enforcement.     

Web Services for Geographic Information Systems

A surge in Web services and applications for geographic information systems (GISs) has made large spatial-data archives available over the Internet. Significant accomplishments in GIS Web services have led to several exemplifying map and image services that adhere to Web services standards and provide geospatial data and digital maps to enterprise developers.     

Web服务的可用性测量

利用一种新的消息传递机制,从请求者的角度在服务请求者和服务提供者之间进行消息交互的同时进行Web服务可用性的测量,并提出了一套关于Web服务可用性的量化指标,为服务请求者的选择提供依据.     

应用于Web服务合成的一种有效的Web服务发现策略

随着Web服务的流行，如何发现Web服务为研究者们提出了挑战．文中将描述Web服务的信息分为服务操作信息（OWSDL）、服务功能信息（一般属性）和服务约束信息（实例属性）．基于描述服务的三部分信息，分三步实现服务查找．第一步，基于领域本体商业规范OWSDL实现服务操作同构；第二步，基于服务概要描述的一般属性，满足服务的功能需求；第三步，应用服务匹配度模型，基于概要描述的实例属性，按需为消费者提供恰当的服务．最后，通过实例证明了该方法是一种有效的Web服务发现策略．     

基于Web的多重身份认证的设计与实现

本文介绍了在基于Web的应用系统中的身份认证问题，设计并实现了基于多重认证技术的系统身份认证解决方案：利用防火墙防止外部用户登录；利用IP／MAC认证方法防止非法客户端的访问；通过用户名、密码及汉字验证码认证，防止利用程序的分析破解：利用服务器用户认证方法防止非法角色的访问；利用数据加密对数据库进行加密。     

新一代的Web Services技术

电子商务的应用对在Internet上的互操作提出了更高的要求,介绍了基于XML的Web Services结构框架,技术目标,并就其存在的问题和发展方向进行了讨论。     

Web Services集成技术

本文首先介绍了Web Services的基本概念和应用背景,在此基础上分析当前使用的Web Services合成的意义。然后阐述基本的Web Services合成方式及其介绍在Web服务中消除语义的方法,重点研究了动态服务合成过程和语义分析方法,最后对于Web Services的集成应用进行了展望。     

Web Services与传统Web应用

本文针对Web Services技术实质以及与传统Web应用区别，分别从技术、商务价值和编程实现上进行了比较研究，展现了Web Services的独特之处与应用前景。