Web Services Business Process Research Articles

Performance Analysis of Service Oriented Software

Web Services Business Process Execution Language (WS-BPEL) is a promising language describing the Service Oriented Software (SOS) orchestrations in form of Business Processes (BP), but it lacks of a sound formal semantic, which hinders the formal analysis and verification of business processes specified in it. Formal methods, like Petri Nets, may provide a means to analyse WS-BPEL processes, evaluating its performance, detecting weaknesses and errors in the process model already at design-time. This article addresses quality of SOS orchestrations created using the WS-BPEL and a framework ”SOASPE” for transformation of WS-BPEL into Generalized Stochastic Petri Nets is proposed to analise the performance and throughput of SOS, based on the execution of orchestrated processes.

BPEL Extensions to User-Interactive Service Delivery

Web Services Business Process Execution Language) is adopted industrial-wide as the de facto service composition standard. However, a BPEL composite service is typically treated as a fully automated service flow that orchestrates multiple web services and involves no user interactions-a desirable feature for service delivery, and is presently not included in the BPEL standard. In this work, we propose an extension to BPEL to infuse user interactions into composite services along three dimensions: (1) to develop two BPEL extension activities to describe the inner workings of user interactions in BPEL service and the rendering of service user interfaces; (2) to provide a wizard-style mechanism to guide the user to interact with the service flow in accordance with the sequence of service execution; and (3) to devise a UI service communication protocol to facilitate secure cross-domain communication among UI services from various domains. An enhanced BPEL engine with a service UI rendering engine has been accordingly developed.

A Survey on Distributed Access Control Systems for Web Business Processes

Middleware influenced the research community in developing a number of systems for controlling access to distributed resources. Nowadays a new paradigm for lightweight integration of business resources has started to hold Business Processes for Web Services. Authorization and access control policies for Web Services proto- cols and distributed systems are well-studied and standardized, but there is not yet a comprehensive proposal for distributed access control architecture. This paper surveys the available approaches and analyzes them for a better understanding of what these systems have and what they still need to address the security challenges.

B2B Services: Worksheet-Driven Development of Modeling Artifacts and Code

In the development process of a B2B system, it is crucial that the business experts are able to express and evaluate agreements and commitments between the partners, and that the software engineers get all necessary information to bind the private process interfaces to the public ones. UN/CEFACT's modeling methodology (UMM) is a Unified Modeling Language (UML) profile for developing B2B processes. The formalisms introduced by UMM's stereotypes facilitate the communication with the software engineers. However, business experts—who usually have a very limited understanding of UML—prefer expressing their thoughts and evaluating the results by plain text descriptions. In this paper, we describe an approach that presents an equivalent of the UMM stereotypes and tagged values in text-based templates called worksheets. This strong alignment allows an integration into a UMM modeling tool and ensures consistency. We show how a specially designed XML-based worksheet definition language allows customization to special needs of certain business domains. Furthermore, we demonstrate how information kept in worksheets may be used for the semi-automatic generation of pattern-based UMM artifacts which are later transformed to web service definition language and business process execution language code.

Comparing and evaluating Petri net semantics for BPEL

We compare two Petri net semantics for the Web Services Business Process Execution Language (BPEL). The comparison reveals different modelling decisions. These decisions together with their consequences are discussed. We also give an overview of the different properties that can be verified on the resulting models. A case study helps to evaluate the corresponding compilers which transform a BPEL process into a Petri net model.

IQoS-aware exception resolution for BPEL processes: a middleware-based framework and performance evaluation

Web Services Business Process Execution Language (WS-BPEL) is widely used nowadays for specifying and executing composite business processes. During the execution, however, of such business processes, a number of faults stemming from the nature of SOA may occur. The WS-BPEL scenario designer must therefore use the provisions offered by WS-BPEL to catch these exceptions and resolve them. The system fault handler specification, however, is an additional task for the WS scenario designer, while the presence of such handlers within the scenario necessitates extra maintenance activities. In this paper, we propose a middleware-based framework for system exception resolution, which undertakes the tasks of failure interception, discovery of alternative services and their invocation. The process of selecting the alternative services can be driven by process consumer-specified Quality of Service (QoS) policy. Moreover, the middleware arranges for bridging syntactic differences between the originally invoked services and functionally equivalent replacements to it, by employing XSLT-based transformations. The middleware is deployed and maintained independently of the WS-BPEL scenarios, thus removing the need for specifying and maintaining system fault handlers within the scenarios. We also present performance measures, establishing that the overhead imposed by the addition of the proposed middleware layer is minimal.

From WS‐CDL choreography to BPEL process orchestration

PurposeThe web service choreography description language (WS‐CDL) is a specification for describing multi‐party collaboration based on web services from a global point‐of‐view. WS‐CDL is designed to be used in conjunction with the web services business process execution language (WS‐BPEL or BPEL). As WS‐CDL is a new choreography language, there has been doubt about the feasibility of a transformation to BPEL. This article aims to show how BPEL process definitions of parties involved in a choreography can be derived from the global WS‐CDL model and what the limitations of such a derivation are.Design/methodology/approachThe authors implemented a prototype of the mappings as a proof of concept.FindingsThe automatic transformation leverages the quality of software components interacting in the choreography as advocated in the model driven architecture (MDA) concept. The mapping reveals that some information has to be added manually to the generated BPEL, in particular, choice conditions and private activities.Research limitations/implicationsA comprehensive evaluation of WS‐CDL with respect to the interaction patterns is still missing. As a resolution to this issue, the authors propose the modelling of choreographies by the help of a more abstract language – in the sense of being more independent of underlying technology – like UML 2.0 Activity Diagrams.Practical implicationsThe automation of the mapping offers substantial speed‐up of the engineering process. Additionally, the automatic generation of BPEL stubs minimizes the risk of inconsistent process implementations by the parties.Originality/valueThe core contribution is to show how BPEL process definitions for parties involved in a choreography can be derived from a global WS‐CDL model.

A reflective approach for dynamic change of BPEL process

WS-BPEL (Web Service Business Process Execution Language), as an emerging workflow standard, provides a simple and effective way to construct Web Services-oriented workflows. However, to the best of our knowledge, few effort from the industry and academia has addressed the dynamic change problems of BPEL process. This paper proposes a reflective approach to solve this problem. In this paper, a formal meta-object model of process instance is defined; the behavioral consistency criterion based on this model is proposed; a set of modification primitives are given to modify the meta-object while keeping the change atomic and consistent; and in addition, the MOP is offered to provide the programming interfaces for dynamic BPEL process change.

Business Process Standards – Current Landscape (Landkarte aktueller Standards zur Beschreibung von Geschäftsprozessen: WS-BPEL, BPEL4People, BPEL-SPE, BPELJ, SCA)

Summary The landscape of current specifications for the description of business processes consists of the Web Services Business Process Execution Language (WS-BPEL) as an adopted standard, and a number of functional extensions allowing for human interactions (BPEL4People), sub-processes with life-cycle coupling (BPEL-SPE), and Java integration (BPELJ). Also relevant for the assembly of portable, executable applications is the Service Component Architecture (SCA) which provides a model for service-based components complementing WS-BPEL. This paper provides an overview of the current business process standards landscape and its further evolution.

기업간 비즈니스 프로세스 등록저장소를 위한 메타데이터 온톨로지 설계

B2B 등록저장소는 기엽의 프로파일, 비즈니스 문서, 비즈니스 프로세스, 제공 서비스 등의 B2B 관련 비즈니스 정보들을 저장하고 거래 파트너 또는 잠재 거래 파트너들에게 정보를 제공하는 시스템이다. 본 논문에서는 이 중 B2B 비즈니스 프로세스의 등록저장소의 설계에 초점을 맞추어, 이를 지원하기 위한 메타데이터 온톨로지를 제시한다. 현재 ebXML BPSS (Business Process Specification Schema), WSBPEL (Web Service Business Process Execution Language), BPMN (Business Process Modeling Notation) 등의 다수의 비즈니스 프로세스 정의 언어들이 시장에서 경쟁하고 있다. 이러한 상황을 고려하여, 다수의 다른 프레임워크에서 표현된 비즈니스 프로세스를 등록저장하기 위해서 제시된 메타 데이터 온톨로지는 3개 계층, 공통 메타데이터, 언어별 메타데이터, 상호연관관계 메타데이터로 구성된다. 제시된 메타데이터 온톨로지의 유용성을 보이기 위해서, ebXML BPSS 와 WSBPEL로 표현된 비즈니스 프로세스의 온톨로지 내에 저장을 예제로 제시한다. 또한 제시된 메타데이터 온톨로지의 구현을 위해서 ebXML 등록저장소 정보모델로의 매핑 방안을 제시한다. B2B registries are information systems to register B2B related business information such as companies' profiles, business documents, business processes, and services and to provide query facilities to find information about potential business partners. Focusing on the design of the registry for B2B business processes, in this paper, a metadata ontology is designed to register B2B business processes. In practice, there are several competitive business process definition languages such as ebXML BPSS (Business Process Specification Schema), WSBPEL (Web Service Business Process Execution Language), BPMN (Business Process Modeling Notation), and so on. In order to register heterogeneous business processes based on different representation frameworks, the proposed metadata ontology consists of three layers, common metadata, language-specific metadata, and interrelationship metadata. To show the usefulness of the proposed metadata ontology, two examples which are represented by ebXML BPSS and WSBPEL respectively are described in order to show how the proposed metadata ontology is used to registry B2B business processes. To implement the proposed metadata ontology using ebXML registry, metadata mapping scheme to ebRIM (ebXML Registry Information Model) is also suggested.

JOLIE: a Java Orchestration Language Interpreter Engine

Service oriented computing is an emerging paradigm for programming distributed applications based on services. Services are simple software elements that supply their functionalities by exhibiting their interfaces and that can be invoked by exploiting simple communication primitives. The emerging mechanism exploited in service oriented computing for composing services –in order to provide more complex functionalities– is by means of orchestrators. An orchestrator is able to invoke and coordinate other services by exploiting typical workflow patterns such as parallel composition, sequencing and choices. Examples of orchestration languages are XLANG [IBM, “XLANG: Web Services for Business Process Design,”http://www.gotdotnet.com/team/xml_wsspecs/xlang-c/default.htm] and WS-BPEL [OASIS, “Web Services Business Process Execution Language Version 2.0, Working Draft,”http://www.oasis-open.org/committees/download.php/10347/wsbpel-specification-draft-120204.htm]. In this paper we present JOLIE, an interpreter and engine for orchestration programs. The main novelties of JOLIE are that it provides an easy to use development environment (because it supports a more programmer friendly C/Java-like syntax instead of an XML-based syntax) and it is based on a solid mathematical underlying model (developed in previous works of the authors [N. Busi, R. Gorrieri, C. Guidi, R. Lucchi and G. Zavattaro, Towards a formal framework for Choreography, in: Proc. of 3rd International Workshop on Distributed and Mobile Collaboration (DMC 2005) (2005), N. Busi, R. Gorrieri, C. Guidi, R. Lucchi and G. Zavattaro, Choreography and orchestration conformance for system design, in: Proc. of 8th International Conference on Coordination Models and Languages (COORDINATION'06), LNCS to appear, 2006, C. Guidi and R. Lucchi, Mobility mechanisms in service oriented computing, in: Proc. of 8th International Conference on on Formal Methods for Open Object-Based Distributed Systems (FMOODS'06), LNCS to appear, 2006]).

CSP-Based Verification for Web Service Orchestration and Choreography

Service-oriented computing aspires to an unprecedented level of platform-independence and inter-operability of software components for intra- and inter-organizational business processes through standard protocols and languages for workflows and process-oriented applications. The Web Service Business Process Execution Language (WS-BPEL) and the Web Service Choreography Description Language (WS-CDL) are two major languages for modeling and implementing Web services-based business processes. A Web service can be modeled in WS-BPEL by an abstract process describing its external behavior in terms of message exchanges with other participants (Web services). The abstract process can then be refined with more details to become an executable process. On the other hand, WS-CDL serves as a behavioral modeling language for the collaboration between multiple participants (Web services) within the same business process from a global point of view. In this paper, we outline how Communicating Sequential Processes (CSP) can be used as a formal basis for verifying the behavioral consistency among abstract and executable processes together with choreographic descriptions.

Business processes for Web Services: Principles and applications

The Business Process Execution Language for Web Services (BPEL4WS or BPEL for short) is an XML-based language for defining business processes that provides an interoperable, portable language for both abstract and executable processes and that was designed from the beginning to operate in the heterogeneity and dynamism that is commonplace in information technology today. BPEL builds on the layers of flexibility provided by the Web Services stack, and especially by XML. In this paper, we provide a brief introduction to BPEL with emphasis on architectural drivers and basic concepts. Then we survey ongoing BPEL work in several application areas: adding quality of service to BPEL, extending BPEL to activities involving humans, BPEL for grid computing, and BPEL for autonomic computing.

Empowering collaborative commerce with Web services enabled business process management systems

Collaborative commerce (C-Commerce) is a set of technologies and business practices that allows companies to build stronger relationships with their trading partners through integrating complex and cross-enterprise processes governed by business logic and rules, as well as workflows. Business Process Management (BPM) is a key element of C-Commerce solutions for complex process coordination. It provides a mechanism to support e-businesses in modeling, deploying, and managing business processes that involve various applications with greater flexibility. Traditional BPM solutions often lack the capability to integrate external applications in that they have very limited support for interoperability. In recent years, Web services have emerged as a promising enabling technology for BPM in support of C-Commerce. Web services offer effective and standard-based means to improve interoperability among different software applications over Internet protocols. This paper aims to give an in-depth analysis of BPM and Web services in the context of C-Commerce. We propose an architecture for Web services enabled BPM in C-Commerce and provide technical insights into why Web services can enhance business process coordination. Finally, an implementation of a dynamic e-procurement application based on the proposed architecture is presented. With the advent of Web service standards and business process integration tools that support them, BPM systems enabled by Web services are empowering the development of more flexible and dynamic C-Commerce.