Web服务事务QoS管理

随着Web服务在电子商务等应用领域的快速发展,Web服务中的QoS管理,特别是Web服务事务中的QoS管理,成了一个迫切需要解决的问题,它对于服务的提供商和用户都同样重要。但是Web的动态性、不可预见性等特点使得提供全面的QoS管理成为一个富有挑战性的工作。并且,现有的Web事务管理沿用了数据库的事务管理模式,不能提供深入全面的支持。为了加强QoS管理,该文提出了基于QoS管理的事务计算模型和基于QoS的主动两阶段提交协议QA-2PC。QA-2PC即使在操作系统和网络不能提供完全保障的前提下,也可以保证全面的质量服务。     

An overview of workflow management: From process modeling to workflow automation infrastructure

Today's business enterprises must deal with global competition, reduce the cost of doing business, and rapidly develop new services and products. To address these requirements enterprises must constantly reconsider and optimize the way they do business and change their information systems and applications to support evolving business processes. Workflow technology facilitates these by providing methodologies and software to support (i) business process modeling to capture business processes as workflow specifications, (ii) business process reengineering to optimize specified processes, and (iii) workflow automation to generate workflow implementations from workflow specifications. This paper provides a high-level overview of the current workflow management methodologies and software products. In addition, we discuss the infrastructure technologies that can address the limitations of current commercial workflow technology and extend the scope and mission of workflow management systems to support increased workflow automation in complex real-world environments involving heterogeneous, autonomous, and distributed information systems. In particular, we discuss how distributed object management and customized transaction management can support further advances in the commercial state of the art in this area. Recomended by: Omran Bukhres and e. Kühn     

e-Business process interleaving: Managerial and technological implications*

The emergence of Internet as the hub of e-business has made business process integration another important frontier of information management and technology. As a result, the management of inter-organizational business processes is now a major concern of corporate managers. We envision that the new and complex ways of interactions among business partners in a supply web will need to be managed effectively as the next generation of the Internet makes cross company workflow a reality. Consequently, business managers are confronted with new issues and new decisions in the strategic and operational aspects of process integration. To facilitate the understanding of these issues, we introduce a new paradigm of business computing referred to as E-business Process Interleaving, which emphasizes the complex and dynamic integration of e-business processes across company boundaries. In this paper, we outline various impacts of this new phenomenon on information management and technology and investigate the enabling technologies of e-business process interleaving. We believe that our work can help the development of the next generation of corporate information infrastructure that enables greater degree of e-business process integration.This research was partly supported by CITM grants including the DoD contract (2000–2001), N00244-00-C0108, and by the State of California NGI Program.     

Cross-Organizational Transaction Support for E-Services in Virtual Enterprises

In recent years, workflow management systems have become an accepted technology to support automation in process-centric environments. Lately, organizations concentrate more and more on their core business processes while outsourcing supporting processes to other organizations, thereby forming virtual enterprises. The organizations forming the virtual enterprise operate in a B2B e-commerce setting in which provider organizations perform e-services for consumer organizations. To apply workflow management technology in these virtual enterprises, current workflow management systems need to be extended to offer support for cross-organizational processes. Transaction support, already considered an important issue in intra-organizational workflow management systems, must be extended to deal with the cross-organizational aspects as well. This paper presents a high-level, compensation based transaction model and a flexible architecture to support thistransaction model, as required by cross-organizational workflow processes. Characteristic of the model is the flexibility in rollback semantics by combining rollback modes and rollback scopes. This is supported by a dynamically composed architecture that is configured using the agreements that are specified in an electronic contract that has been established between the participating organizations. The transaction model supported by the dynamically composed architecture is implemented in a prototype system, based on commercial workflow management technology.     

基于扩展染色Petri网的工作流过程模型

尽管已有广泛领域应用,但工作流系统在处理业务流程不确定的和动态的参数规格表时存在局限性。为此,本文提出基于扩展染色petri网的CPWF-net以及定义变迁行为和原子过程作为CPWF-net工作流模式结构的支持。这些工作流模式是从微观上进行处理,并可应用于动态不稳定的与时间和数据相关的环境中。本文通过CPWF-net执行程序检测工作流错误或异常执行状态,评估动态业务流程的整体执行时间,证实所提方法的有效性。     

Web服务组合中商业事务处理的研究

Web服务组合已经成为业界的研发热点．在Web服务组合中，不同的成员Web服务之间存在着操作一致性和可靠性的处理要求，需要在Web服务组合中提供对于事务处理的支持．尽管目前业界已经存在许多的Web服务组合模型和描述语言，但是都没有提供对于事务处理的支持．本文分析了Web服务组合中的事务处理需求，通过扩展在Web服务组合描述语言中已经占据主导地住的BPEL4WS规范，在BPEL4WS中引入了对于主流的Web服务事务协议的支持，并在此基础上实现了一个原型系统TAWSCRS．     

Applying Propositional Logic to Workflow Verification

The increasing complexity of business processes in the era of e-business has heightened the need for workflow verification tools. However, workflow verification remains an open and challenging research area. As an indication, most of commercial workflow management systems do not yet provide workflow designers with formal workflow verification tools. We propose a logic-based verification method that is based on a well-known formalism, i.e., propositional logic. Our logic-based workflow verification approach has distinct advantages such as its rigorous yet simplistic logical formalism and its ability to handle generic activity-based process models. In this paper, we present the theoretical framework for applying propositional logic to workflow verification and demonstrate that logic-based workflow verification is capable of detecting process anomalies in workflow models.     

Exception Handling for Conflict Resolution in Cross-Organizational Workflows

Workflow management systems (WfMSs) are being increasingly deployed to deliver e-business transactions across organizational boundaries. To ensure a high service quality in such transactions, exception-handling schemes for conflict resolution are needed. The conflicts primarily arise due to failure of a task in workflow execution because of underlying application, or controlling WfMS component failures or insufficient user input. So far, little progress has been reported in addressing conflict resolution in cross-organizational business processes, though its importance has been recognized. In this paper, we identify the exception handling techniques that support conflict resolution in cross-organizational settings. In particular, we propose a novel, bundled exception-handling approach, which supports (1) exception knowledge sharing--sharing exception specifications and handling experiences, (2) coordinated exception handling, and (3) intelligent problem solving--using case based reasoning to reuse exception handing experiences. A prototype of this exception handling mechanism is developed and integrated as a part of the METEOR Workflow Management System. An evaluation of our approach is also presented through some sample workflow applications.     

工作流元模型的研究与应用

由于工作流技术具有在异构环境中处理复杂事务的能力,所以在科学研究、电子政务和商务等方面引起了广泛的关注,涌现出一些研究成果和产品.其中,大部分的研究集中于工作流的调度、与数据库和遗产系统的接口等技术方向,对工作流管理系统的体系结构、模型和定义语言等方面的研究相对来说比较薄弱.分析了工作流联盟的工作流元模型,并结合实际情况,对工作流元模型以及工作流定义语言作了适当的改进和扩展,以适应日益增长的业务过程的变化和新技术的应用.     

On-demand e-supply chain integration: A multi-agent constraint-based approach

With e-business emerging as a key enabler to drive supply chains, the focus of supply chain management has been shifted from production efficiency to customer-driven and partnership synchronization approaches. This strategic shift depends on the match between the demands and offerings that deliver the services. To achieve this, we need to coordinate the flow of information among the services, and link their business processes under various constraints. Existing approaches to this problem have relied on complete information of services and resources, and have failed to adequately address the dynamics and uncertainties of the operating environments. The real-world situation is complicated as a result of undetermined requirements of services involved in the chain, unpredictable solutions contributed by service providers, and dynamic selection and aggregation of solutions to services. This paper examines an agent-mediated approach to on-demand e-business supply chain integration. Each agent works as a service broker, exploring individual service decisions as well as interacting with each other for achieving compatibility and coherence among the decisions of all services. Based on the framework, a prototype has been implemented with simulated experiments highlighting the effectiveness of the approach.     

工作流参考模型研究与基于J2EE实现

实施工作流管理的主要目的是通过合理地调用和分配与活动有关的信息和资源来实现企业业务处理的高效、自动化执行.本文基于J2EE规范和工作流管理联盟规范,研究了抽象的工作流参考模型的功能组成部件、工作流执行服务、工作流执行引擎、接口以及接口间的信息交换,提出了一种由工作流引擎驱动的基于J2EE的框架实现,在此基础之上,工作流管理系统能很好地实现将企业业务处理过程中活动、信息及资源的调度策略集成到业务的自动协调操作中来.     

工作流安全域层次结构研究

在电子商务迅猛发展,B2B的电子商务成为企业间协作的主流,工作流管理系统作为强大的使能工具在企业业务流程经营过程中起着举足轻重作用的时候,工作流管理系统的安全已成为人们关注的焦点。多层面的综合集成与综合管理和控制,是解决系统复杂性问题的基本思路。该文将这一思想应用于工作流安全研究,在简单介绍相关工作的基础上,提出了安全域层次结构,并就管理层、应用层和数据层、以及网络层涉及的安全问题进行了讨论。这对工作流安全的研究是一种有意的探索。     

Multi-agent collaboration for B2B workflow monitoring

Business-to-business (B2B) applications environments are exceedingly dynamic and competitive. This dynamism is manifested in the form of changing process requirements and time constraints. However, current workflow management technologies have difficulties to solve the challenges problems, such as: how to deal with the dynamic nature of B2B commerce processes, how to manage the distributed knowledge and recourses, and how to reduce the transaction risk. In this paper, a collaborative multi-agent system has been proposed. Multiple intelligent agents in our system can work together not only to identify the workflow problems, but also to solve such problems, by applying business rules, such as re-organizing the procurement and the transaction processes, and making necessary workflow process changes.     

工作流中的长事务模型

本文首先分析了工作流长事务的特性,并针对工作流中频繁出现的长事务问题基础上提出了一种多层事务模型FLTM。该事务模型并不要求所有事务都遵循严格的ACID特性,它可以刻画从松弛到严格的各种事务要求,用户可以根据具体的应用定制事务补偿的终点和事务失败时的处理方式。本文给出了松弛的原子性、一致性和隔离性的定义,并形式地描述了FLTM事务的补偿和执行过程。     

BSWF:一个基于B/S方式的工作流管理系统

本文分析并讨论了基于Web的工作流管理系统的实现方法及关键技术，介绍了作者作用VC6和Delphi5以及Web/DCOM的工作流管理的原型系统BSWF。原型系统模拟了跨企业供应链的业务过程，同时客户端的浏览器可以B／S方式插入，观察并监视业务活动的执行情况。     

Automatic Transaction Compensation for Reliable Grid Applications

Abstract As grid technology is expanding from scientific computing to business applications, service oriented grid computing is aimed at providing reliable services for users and hiding complexity of service processes from them. The grid services for coordinating long-lived transactions that occur in business applications play an important role in reliable grid applications. In this paper, the grid transaction service （GridTS） is proposed for dealing with long-lived business transactions. We present a compensation-based long-lived transaction coordination algorithm that enables users to select results from committed sub-transactions. Unlike other long-lived transaction models that require application programmers to develop corresponding compensating transactions, GridTS can automatically generate compensating transactions on execution of a long-lived grid transaction. The simulation result has demonstrated the feasibility of GridTS and effectiveness of the corresponding algorithm.     

Coordinating multiple agents for workflow-oriented process orchestration

Distributed component-based services and semantic web services are promising technologies for next generation inter-enterprise integration. The dynamic nature of this domain presents a complex problem for tools that intend to support this cross-organizational integration. However, the autonomy and adaptation of software agents represent a viable solution for the composition and enactment of cross-organizational services. Currently, there are few studies that measure the impact of the dynamic environmental effects on service composition. On an on-going basis, composite services or workflow processes of web services may be constantly changing in terms of responsiveness of services, accessibility of services and their meta-information, business process schema changes, etc. These conditions impact what interactions a team of agents must undergo to achieve a specific process derived of composite web services. This paper describes an approach, model, and supporting software toward the efficient design of interaction protocols for coordinating agent teams in the business process orchestration domain. This approach considers several environmental conditions related to the dynamism of the Internet.     

Web services technology in support of business transactions

Advanced business applications typically involve well-defined business functions such as payment processing, shipping and tracking, determining new product offerings, granting/extending credit, managing market risk and so on. These reflect commonly standard business functions that apply to a variety of application scenarios. Although such business functions drive transactional applications between trading partners they are completely external to current Web services transaction mechanisms and are only expressed as part of application logic. To remedy this situation, this paper proposes a business-aware Web services transaction model and support mechanisms, which is driven by common business functions. The model allows expressing business functions such as payment and credit conditions, delivery conditions, business agreements stipulated in SLAs, liabilities and dispute resolution policies. It allows blending these business functions with QoS criteria such as security support to guarantee integrity of information, confidentiality, and non-repudiation. Part of this research reported is funded by the Dutch Organization for Scientific Research (NWO) under the project eXecution of Transactional Contracted Electronic Services (XTC), project No. 612.063.305.     

An experience report on developing an automated web services platform

Web services have attracted significant industry interest as a low-cost and flexible technology alternative to distributed object and proprietary message-oriented methods for delivery of on-demand business processes, enabling intra-organizational systems integration, and in the long term, development of dynamic inter-organizational process networks that may revolutionize B2C and B2B e-commerce. Exploiting this latent potential of web services technology requires the development of automated techniques for scalable and reliable service composition and execution in web service platforms. In this paper, we summarize our experience in developing an architectural framework for web services platforms, called Integrated Service Planning and Execution architecture (ISP & E). The use of recent advances in AI planning, learning and semantic web technologies for service composition, reliable service execution, transaction synthesis, and model-driven deployment of services is discussed. Furthermore, we discuss implications for and research issues in the development of web services based systems to aid e-business.