A Classification of BPEL Extensions

The Business Process Execution Language (BPEL) has emerged as de-facto standard for business processes implementation. This language is designed to be extensible for including additional valuable features in a standardized manner. There are a number of BPEL extensions available. They are, however, neither classified nor evaluated with respect to their compliance to the BPEL standard. This article fills this gap by providing a framework for classifying BPEL extensions, a classification of existing extensions, and a guideline for designing BPEL extensions

An intelligent framework for dynamic web services composition in the semantic web

As Web services are being increasingly adopted as the distributed computing technology of choice to securely publish application services beyond the firewall, the importance of composing them to create new, value-added service, is increasing. Thus far, the most successful practical approach to Web services composition, largely endorsed by the industry falls under the static composition category where the service selection and flow management are done a priori and manually. The second approach to web-services composition aspires to achieve more dynamic composition by semantically describing the process model of Web services and thus making it comprehensible to reasoning engines or software agents. The practical implementation of the dynamic composition approach is still in its infancy and many complex problems need to be resolved before it can be adopted outside the research communities. The investigation of automatic discovery and composition of Web services in this thesis resulted in the development of the eXtended Semantic Case Based Reasoner (XSCBR), which utilizes semantic web and AI methodology of Case Based Reasoning (CBR). Our framework uses OWL semantic descriptions extensively for implementing both the matchmaking profiles of the Web services and the components of the CBR engine. In this research, we have introduced the concept of runtime behaviour of services and consideration of that in Web services selection. The runtime behaviour of a service is a result of service execution and how the service will behave under different circumstances, which is difficult to presume prior to service execution. Moreover, we demonstrate that the accuracy of automatic matchmaking of Web services can be further improved by taking into account the adequacy of past matchmaking experiences for the requested task. Our XSCBR framework allows annotating such runtime experiences in terms of storing execution values of non-functional Web services parameters such as availability and response time into a case library. The XSCBR algorithm for matchmaking and discovery considers such stored Web services execution experiences to determine the adequacy of services for a particular task. We further extended our fundamental discovery and matchmaking algorithm to cater for web services composition. An intensive knowledge-based substitution approach was proposed to adapt the candidate service experiences to the requested solution before suggesting more complex and computationally taxing AI-based planning-based transformations. The inconsistency problem that occurs while adapting existing service composition solutions is addressed with a novel methodology based on Constraint Satisfaction Problem (CSP). From the outset, we adopted a pragmatic approach that focused on delivering an automated Web services discovery and composition solution with the minimum possible involvement of all composition participants: the service provider, the requestor and the service composer. The qualitative evaluation of the framework and the composition tools, together with the performance study of the XSCBR framework has verified that we were successful in achieving our goal

Towards Flexible Process Support on Mobile Devices

Ubiquitous computing is considered as enabler for linking everyday life with information and communication technology. However, developing pervasive and mobile applications that provide personalized user assistance still constitutes a challenge. Mobile application scenarios are diverse and encompass domains like healthcare, logistics, and sales. For their support two fundamental technologies with increasing maturity are emerging: development frameworks for mobile devices and light-weight process engines. Their integrated use, however, is in a rather premature state. Generally, the use of a process engine for supporting mobile collaboration raises many challenging issues. This paper picks up some of these challenges and shows how we have coped with them in the MARPLE project. MARPLE targets at a tight integration of process management technology with mobile computing frameworks in order to enable mobile process support in advanced application scenarios. We give insights into the MARPLE architecture and its components.In particular, we introduce the MARPLE process engine, which enables light-weight as well as flexible process support on mobile devices. This will be key for mobile user assistance in advanced application scenarios

A robust client-driven distributed service localisation architecture

The fundamental purpose of service-oriented computing is the ability to quickly provide software resources to global users. The main aim of service localisation is to provide a method for facilitating the internationalisation and localisation of software services by allowing them to be adapted to different locales. We address lingual localisation by providing a service interface translation using the latest web services technology to adapt services to different languages and currency conversion as an example of regulatory localisation by using real-time data provided by the European Central Bank. Units and Regulatory Localisations are performed by a conversion mapping, which we have generated for a subset of locales. The aim is to investigate a standardised view on the localisation of services by using runtime and middleware services to deploy a localisation implementation. We apply traditional software localisation ideas to service interfaces. Our contribution is a localisation platform consisting of a conceptual model classifying localisation concerns and the definition of a number of specific platform services. The architecture in which this localisation technique is client-centric in a way that it allows the localisation to be controlled and managed by the client, ultimately providing more personalisation and trust. It also addresses robustness concerns by enabling a fault-tolerant architecture for third-party service localisation in a distributed setting

Literature Survey of Performance Benchmarking Approaches of BPEL Engines

Despite the popularity of BPEL engines to orchestrate complex and executable processes, there are still only few approaches available to help find the most appropriate engine for individual requirements. One of the more crucial factors for such a middleware product in industry are the performance characteristics of a BPEL engine. There exist multiple studies in industry and academia testing the performance of BPEL engines, which differ in focus and method. We aim to compare the methods used in these approaches and provide guidance for further research in this area. Based on the related work in the field of performance testing, we created a process engine specific comparison framework, which we used to evaluate and classify nine different approaches that were found using the method of a systematical literature survey. With the results of the status quo analysis in mind, we derived directions for further research in this area

P2P and SOA architecture for digital libraries

Doutoramento em Engenharia InformáticaIn an information-driven society where the volume and value of produced and consumed data assumes a growing importance, the role of digital libraries gains particular importance. This work analyzes the limitations in current digital library management systems and the opportunities brought by recent distributed computing models. The result of this work is the implementation of the University of Aveiro integrated system for digital libraries and archives. It concludes by analyzing the system in production and proposing a new service oriented digital library architecture supported in a peer-to-peer infrastructureNuma sociedade em que o volume e o valor da informação produzida e disseminada tem um peso cada vez maior, o papel das bibliotecas digitais assume especial relevo. O presente trabalho analisa as limitações dos actuais sistemas de gestão de bibliotecas digitais e as oportunidades criadas pelos mais recentes modelos de computação distribuída. Deste trabalho resultou a implementação do sistema integrado para bibliotecas e arquivos digitais da Universidade de Aveiro. Este trabalho finaliza debruçando-se sobre o sistema em produção e propondo uma nova arquitectura de biblioteca digital sustentada numa infrastrutura peer-to-peer e orientada a serviços

Mobile Business Processes : Challenges, Opportunities and Effect

Smartphones and tablets have become an important part of people’s daily life and people have started to use them for work purposes as well. Mobile computing has location and time flexibility advantages that enterprise can utilize with care. The world of mobile technologies is fragmented. It can be a complex task for a non-mobile software company to decide what kind of smartphone application they want for their customers. People have different expectations on mobile applications and their usage habits differ. Mobile applications are more prone to disturbance because of their nature and again still performing critical tasks. They cannot be treated same as stationary computers in terms of business process support. This thesis presents an analysis of effects and opportunities brought by mobile devices to enterprises from small to large scale based on the literature survey. The thesis helps enterprises to understand what kind of approach to mobile support best suits their needs and how to handle the mobile-specific challenges in their IT systems

Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

Dynamic adaptation of service compositions with variability models

Web services run in complex contexts where arising events may compromise the quality of the whole system. Thus, it is desirable to count on autonomic mechanisms to guide the self-adaptation of service compositions according to changes in the computing infrastructure. One way to achieve this goal is by implementing variability constructs at the language level. However, this approach may become tedious, difficult to manage, and error-prone. In this paper, we propose a solution based on a semantically rich variability model to support the dynamic adaptation of service compositions. When a problematic event arises in the context, this model is leveraged for decision-making. The activation and deactivation of features in the variability model result in changes in a composition model that abstracts the underlying service composition. These changes are reflected into the service composition by adding or removing fragments of Business Process Execution Language (WS-BPEL) code, which can be deployed at runtime. In order to reach optimum adaptations, the variability model and its possible configurations are verified at design time using Constraint Programming. An evaluation demonstrates several benefits of our approach, both at design time and at runtime.This work has been developed with the support of MICINN under the project everyWare TIN2010-18011 and co-financed with ERDF.Alférez Salinas, GH.; Pelechano Ferragud, V.; Mazo, R.; Salinesi, C.; Díaz, D. (2014). Dynamic adaptation of service compositions with variability models. Journal of Systems and Software. 91:24-47. https://doi.org/10.1016/j.jss.2013.06.034S24479