XrML-RBLicensing approach adapted to the BPEL process of composite web services

Web service orchestration represents an open and standards-based approach for connecting web services together leading to higher level of business processes. Business Process Execution Language (BPEL) engines are designed to handle this orchestration. However, web service compositions into BPEL suffer from several non-functional requirements such as security. To address this problem, we propose in this paper a novel approach that is based on a harmony between the licensing concept offered by eXtensible rights Markup Language (XrML), aspect-oriented programming (AOP), and web service compositions in BPEL. Our proposed approach, based on XrML, offers the ability to associate security licenses with activities offered by the composite web services. It allows to automatically generate BPEL aspects depending on the developed licenses, to separate between crosscutting concerns of the composed web services, and provides an easy way to include and update the non-functional requirements (e.g., security) into a BPEL process. It offers also the ability to validate the licenses, at runtime and without affecting the business logic of this model. To evaluate our approach, we have developed an inventory control system (ICS) sample that is composed of several web services. Case study and performance analysis are presented to demonstrate its feasibility as well.     

A layered architecture for flexible Web service invocation

Web service composition is emerging as an interesting approach to integrate business applications and create intra‐organizational business processes. Single Web services are combined to create a complex Web service that will realize the process business logic. Once the process is created, it is executed by an orchestration engine that invokes individual Web services in the correct order. However, Web services composing the workflow sometimes become unavailable during the run‐time phase, blocking process execution. This paper describes an architecture that allows the flexible orchestration of business processes. With this approach, Web services composing the process can be automatically substituted with other compatible Web services during process execution. A methodology is defined to evaluate Web service compatibility based on interface matching, in order to select substitutable Web services. Copyright © 2005 John Wiley & Sons, Ltd.     

Business processes oriented heterogeneous systems integration platform for networked enterprises

Supply chains, dynamic alliances, e-business, extended enterprises, and virtual organizations are typical networked enterprises which are formed based on partner companies’ core competencies. Different partners have different infrastructures; the interoperability among heterogeneous systems is the solid foundation for the networked enterprise to work seamlessly and effectively. Due to the distributed and heterogeneous characteristics of different partner companies, it is a big challenge to implement a satisfying and cost effective solution in the networked enterprise.Aiming at the problems of system integration and cross-system interoperability, Service-Oriented Architecture (SOA) provides a new integration pattern and relative system infrastructure. The key for the development and implementation of SOA is services encapsulation and orchestration of applications through certain mechanism to operate a complex business. However, cross infrastructures services access protection and relative services orchestration are still the bottleneck for the SOA implementation.This paper develops a business processes oriented heterogeneous systems integration platform with relative methodology for networked enterprises integration. The platform is a space distributed and management centralized platform for networked enterprises. The service access agent (SAA) mechanism is developed to realize cross-domains identity authentication, service authorization, and information transmission security. Every Web service or SAA in the platform has a unique ID. The interoperating process only relies on IDs, which endows the platform with a loose coupling feature. Aiming at service orchestration, a graphic service process modelling method is developed, with which the developed process model can link atom Web services and form a complex service. The Java based service orchestration tool provides an ESB (Enterprise Service Bus) independent service orchestration and deployment. Those services that are results of orchestration can be orchestrated as an atom service in another orchestrating process. Thus, the platform can support orchestration decomposition. The structure approach of the business process modelling based platform implementation is developed, which provides a guideline for platform installation, services modelling, service encapsulation, service orchestration, and service deployment. Two cases are provided to illustrate the usage of the platform in industries. The development of this platform is an open source project.     

Grid Service Orchestration Using the Business Process Execution Language (BPEL)

Modern scientific applications often need to be distributed across Grids. Increasingly applications rely on services, such as job submission, data transfer or data portal services. We refer to such services as Grid services. While the invocation of Grid services could be hard coded in theory, scientific users want to orchestrate service invocations more flexibly. In enterprise applications, the orchestration of web services is achieved using emerging orchestration standards, most notably the Business Process Execution Language (BPEL). We describe our experience in orchestrating scientific workflows using BPEL. We have gained this experience during an extensive case study that orchestrates Grid services for the automation of a polymorph prediction application. Using this example, we explain the extent with which the BPEL language supports the definition of scientific workflows. We then describe the reliability, performance and scalability that can be achieved by executing a complex scientific workflow with ActiveBPEL, an industrial strength but freely available BPEL engine. *The work has been funded by the UK EPSRC through grants GR/R97207/01 (e-Materials) and GR/S90843/01 (OMII Managed Programme).     

A Calculus for Generation, Verification and Refinement of BPEL Specifications

Business Process Execution Language for Web Services (WS-BPEL) is the emerging standard for designing Web Services compositions. In this context, formal methods can contribute to increased reliability and consistency in the BPEL design process. In this paper we propose an approach based on the HAL Toolkit that allows verification of the correctness of the behavior of a π-based specification of interacting Web Services, and generates the BPEL processes that have the same behavior. This correlation based on two-way mapping between the π-based orchestration calculus and BPEL. This approach facilitates the verification and refinement process and may be applied to any BPEL implementation.     

Security architecture for virtual organizations of business web services

Virtual organizations (VO) temporarily aggregate resources of different domains to achieve a common goal. Web services are being positioned as the technological framework for achieving this aggregation in the context of cross-organizational business applications. Numerous architectures have been proposed for securing VOs, mostly for scientific research, such that they do not address all the requirements of business-oriented applications. This paper describes these additional requirements and proposes a novel architecture and approach to managing VO access control policies. Business users can focus on designing business processes, exposing web services and managing their VO partnerships, while the architecture supports and secures the web service interactions involved.     

Orchestrating Web Services with BPEL

Effective Web services demand careful synchronization on various abstraction levels. The Business Process Execution Language supports modeling and executing business processes from both the user and systems perspectives. In this way, Web services application developers can use BPEL to orchestrate service interactions in a global system view and to manage individual interactions based on outside events. More and more Web service providers are using BPEL to integrate their services independently of vendors and related programming languages. In this column, we introduce BPEL and presents some guidelines for using it in your Web services management.     

一种基于Agent的语义Web服务编制框架

针对动态、开放网络环境下复杂多变的业务需求,本文在前期语义编程语言SPL研究的基础上,提出一种基于Agent和本体的语义Web服务编制方法,形成一个以语义编程语言SPL为核心的、可适用于将语义Web服务与多A-gent技术无缝集成起来的,进行语义Web服务编制的技术框架。框架实现基于SPL开发和运行支撑平台,该平台为语义Web服务和软件Agent提供必要的运行支持。     

Modeling business processes with BPEL4WS

Business Process Execution Language for Web Services (BPEL4WS) allows defining both, business processes that make use of Web services, and business processes that externalize their functionality as Web services. This short paper introduces the basic language elements of BPEL4WS using a simple example. The concepts underlying the language are briefly explained: establishing bilateral partnerships, correlating messages and processes, defining the order of the activities of a business process, event handling, handling exceptions via long-running transactions, and the usage of BPEL4WS in pure B2B scenarios. The paper finishes off by presenting the resulting application structure and the resulting economical implications.     

A holistic approach to model‐based testing of Web service compositions

The behavior of composed Web services depends on the results of the invoked services; unexpected behavior of one of the invoked services can threat the correct execution of an entire composition. This paper proposes an event‐based approach to black‐box testing of Web service compositions based on event sequence graphs, which are extended by facilities to deal not only with service behavior under regular circumstances (i.e., where cooperating services are working as expected) but also with their behavior in undesirable situations (i.e., where cooperating services are not working as expected). Furthermore, the approach can be used independently of artifacts (e.g., Business Process Execution Language) or type of composition (orchestration/choreography). A large case study, based on a commercial Web application, demonstrates the feasibility of the approach and analyzes its characteristics. Test generation and execution are supported by dedicated tools. Especially, the use of an enterprise service bus for test execution is noteworthy and differs from other approaches. The results of the case study encourage to suggest that the new approach has the power to detect faults systematically, performing properly even with complex and large compositions. Copyright © 2012 John Wiley & Sons, Ltd.     

Simulation-based experimentation for designing reliable and efficient Web service orchestrations in supply chains

The world today is witnessing a growing interest in conducting supply chain business processes electronically using Web services orchestration technology. Fast adoption is often hampered by the need for experimentation to make efficient use of this technology in supply chain processes. In this paper, a simulation-based approach supporting experimentation with the efficiency and reliability of Web service orchestrations in supply chains prior to implementation are presented. The approach simulates the de facto business process specification standard for Web services, BPEL4WS, using Java-based simulation building blocks. A supply chain case study is used to demonstrate and evaluate the approach.     

一种规则驱动的网络服务组装机制

提出了一种规则驱动的服务组装方法,实现了一个基于软件Agent的框架,在运行时刻监控和管理组装流程的执行．该方法给出一个算法将流程规约转化为等价的规则集合以用于指导Agent的行为,并允许用户通过定义一组可插拔(pluggable)的自适应策略,方便地扩展流程对变化的适应能力．框架实现基于反射式中间件平台PKUAS,该平台为网络服务和软件Agent提供运行支持,并基于其反射机制为Agent提供运行时刻的环境信息．     

Behavioral Attestation for Web Services using access policies

Service Oriented Architecture with underlying technologies like web services and web service orchestration opens new vistas for integration among business processes operating in heterogeneous environments. However, such dynamic collaborations require a highly secure environment at each respective business partner site. Existing web services standards address the issue of security only on the service provider platform. The partner platforms to which sensitive information is released have till now been neglected. Remote Attestation is a relatively new field of research which enables an authorized party to verify that a trusted environment actually exists on a partner platform. To incorporate this novel concept in to the web services realm, a new mechanism called WS-Attestation has been proposed. This mechanism provides a structural paradigm upon which more fine-grained solutions can be built. In this paper, we present a novel framework, Behavioral Attestation for Web Services, in which XACML is built on top of WS-Attestation in order to enable more flexible remote attestation at the web services level. We propose a new type of XACML policy called XACML behavior policy, which defines the expected behavior of a partner platform. Existing web service standards are used to incorporate remote attestation at the web services level and a prototype is presented, which implements XACML behavior policy using low-level attestation techniques.     

基于BPEL4WS的Web服务整合研究

业务流程执行语言（BPEL4WS）是整合Web 服务的标准，其作用是将一组现有的服务整合起来，从而定义一个新的 Web 服务。首先介绍了业务流、工作流、以及BPEL4WS在Web服务建模方面的基本概念，建立了BPEL4WS整合Web服务模型，提出了组合服务的方法和过程。最后通过实例证明了BPEL4WS服务整合的实用性。     

How BPEL and SOA are changing Web services development

As the use of Web services grows, organizations are increasingly choosing the Business Process Execution Language for modeling business processes within the Web services architecture. In addition to orchestrating organizations' Web services, BPEL's strengths include asynchronous message handling, reliability, and recovery. By developing Web services with BPEL in mind, organizations can implement aspects of the service-oriented architecture that might previously have been difficult to achieve.     

BPEL中基于有限状态自动机的Web服务自动组合

提出了一种基于有限状态自动机的Web服务自动组合方法,该方法能够自动实现BPEL中抽象业务流程与Web服务的绑定.以有限状态自动机模型形式化地定义了业务流程的外模式和内模式,将Web服务组合问题转化为有限状态自动机问题.利用有限状态自动机的笛卡儿积运算,得出了服务组合系统的行为描述.在此基础上,提出了组合服务存在性的判定依据,进一步给出了组合服务的计算方法,设计并实现了一个演示系统.     

The design with object (DwO) approach to Web services composition

Web services are being adopted, more and more, as a viable means of accessing Web-based applications. With a Web-native XML based solution, Web services can, thus, tackle the problem of heterogeneous sources and make them inter-operable. At present, there is a trend towards deploying business processes as composite Web services, known as Web services compositions. Web services compositions are synthesized by researchers from elementary web services, offering the opportunity for service providers and application developers to create value-added services, through Web services composition. However, a problem exists in the current distribution process of Web services compositions: the general analysis and selection of services can be overly complex and un-systemic. There is a need to manage composite Web services, based on these emerging technologies, but the research related to ranking candidate services and selection of optimization strategies is sparse. Nothing has yet been published that considers the constraints of non-functional service properties. In this paper, a design with object (DwO) approach is proposed. This has the advantage of being an object-orientated concept, which characterizes (i) changing the design object without directly changing the Web services themselves, and (ii) information hiding. A systemic but complete composition process is also proposed for Web services composition, which shows great promise in the emerging demand for composite Web services.     

基于语义Web Service的需求驱动服务合成

语义Web Service(SWS)是应对商务对商务环境的挑战,是迈向自动Web服务的重要步骤.基于SWS的商务服务合成是服务计算领域最为活跃和开放的研究问题之一.提出了一种基于SWS的商务服务合成的基本思想和方法.给出了商务服务合成的形式化模型.介绍了一个服务合成中基于超图的服务集合挖掘方法.给出了面向服务合成的需求驱动服务选择及其解决方案模型.