Aspects of Assembly and Cascaded Aspects of Assembly: Logical and Temporal Properties

Highly dynamic computing environments, like ubiquitous and pervasive computing environments, require frequent adaptation of applications. This has to be done in a timely fashion, and the adaptation process must be as fast as possible and mastered. Moreover the adaptation process has to ensure a consistent result when finished whereas adaptations to be implemented cannot be anticipated at design time. In this paper we present our mechanism for self-adaptation based on the aspect oriented programming paradigm called Aspect of Assembly (AAs). Using AAs: (1) the adaptations process is fast and its duration is mastered; (2) adaptations' entities are independent of each other thanks to the weaver logical merging mechanism; and (3) the high variability of the software infrastructure can be managed using a mono or multi-cycle weaving approach.Comment: 14 pages, published in International Journal of Computer Science, Volume 8, issue 4, Jul 2011, ISSN 1694-081

Semantic Web Services: State of the Art

ABSTRACT Service-oriented architectures (SOA) built on Web services were a first attempt to streamline and automate business processes in order to increase productivity but the utopian promise of uniform service interface standards, metadata, and universal service registries, in the form of the SOAP, WSDL and UDDI standards has proven elusive. Furthermore, the RPC-oriented model of those traditional Web services is not Web-friendly. Thus more and more prominent Web service providers opted to expose their services based on the REST architectural style. Nevertheless there are still problems on formal describing, finding, and orchestrating RESTful services. While there are already a number of different approaches none so far has managed to break out of its academic confines. This paper focuses on an extensive survey comparing the existing state-of-the-art technologies for semantically annotated Web services as a first step towards a proposal designed specifically for RESTful services

Monitoraggio Adattivo del livello di qualità in Architetture Orientate ai Servizi

Formulazione di un approccio adattivo e realizzazione di un meccanismo di monitoraggio e verifica di contratti di livelli di qualità in architetture SO

From Here to Eternity: An Experiment Applying the e-Framework Infrastructure for Education and Research and the SUMO Ontology to Standards-based Geospatial Web Services

A number of efforts have been made in recent years to define standards for the description of resources (including web services) in services oriented architectures. These standards often use description logic ontologies (for example, OWL-S) and are intended to be machine-readable. They have been applied to geospatial web services to describe the functions that those services perform in a way that can be automatically interpreted by systems. By contrast, little effort has gone into the development of human readable descriptions of resources in a services oriented architecture, other than using unstructured natural language. e-Framework is an infrastructure for the higher education environment that provides a typology of human-readable artefacts that can be used to describe resources, and provides an internal structure for those artefacts. e-Framework has thus far not been used with geospatial information even though geospatial information has a number of important roles in education and research, and has a well-organised community of users and creators. This paper applies the e-Framework infrastructure to OGC web services, and also recommends the refinement of e-Framework with the use of the SUMO Upper Level Ontology to define Service Genres, the most abstract level of artefacts in e-Framework. It then illustrates the ways in which the Open Geospatial Consortium standards and specifications may be described in e-Framework. The work evaluates SUMO for e-Framework purposes, finding that its use for Service Genres is possible and offers a number of gains. It also evaluates e-Framework from a geospatial perspective, and shows that e-Framework’s constraints on resource descriptions do not suit the large and complex nature of geospatial web services

Handbuch zur DIANE Service Description

Die DIANE Service Description (DSD) ist eine Sprache, die entwickelt wurde, um elektronische Dienste semantisch eindeutig beschreiben zu können. Motivation fur die Entwicklung von DSD war die vollständige Automatisierung der Dienstnutzung, d.h. beginnend mit einem Funktionsaufruf soll es DSD ermöglichen, automatisch einen geeigneten Dienstgeber zu finden und diesen korrekt aufzurufen. Dieses Handbuch beschreibt die Syntax und die Semantik von DSD im Detail

A flexible model for the semi-automatic location of services

Tesis doctoral inédita. Universidad Autónoma de Madrid, Escuela Politécnica Superior, julio de 200

A knowledge based reengineering approach via ontology and description logic.

Traditional software reengineering often involves a great deal of manual effort by software maintainers. This is time consuming and error prone. Due to the knowledge intensive properties of software reengineering, a knowledge-based solution is proposed in this thesis to semi-automate some of this manual effort. This thesis aims to explore the principle research question: “How can software systems be described by knowledge representation techniques in order to semi-automate the manual effort in software reengineering?” The underlying research procedure of this thesis is scientific method, which consists of: observation, proposition, test and conclusion. Ontology and description logic are employed to model and represent the knowledge in different software systems, which is integrated with domain knowledge. Model transformation is used to support ontology development. Description logic is used to implement ontology mapping algorithms, in which the problem of detecting semantic relationships is converted into the problem of deducing the satisfiability of logical formulae. Operating system ontology has been built with a top-down approach, and it was deployed to support platform specific software migration [132] and portable software development [18]. Data-dominant software ontology has been built via a bottom-up approach, and it was deployed to support program comprehension [131] and modularisation [130]. This thesis suggests that software systems can be represented by ontology and description logic. Consequently, it will help in semi-automating some of the manual tasks in software reengineering. However, there are also limitations: bottom-up ontology development may sacrifice some complexity of systems; top-down ontology development may become time consuming and complicated. In terms of future work, a greater number of diverse software system categories could be involved and different software system knowledge could be explored

Model driven software modernisation

Constant innovation of information technology and ever-changing market requirements relegate more and more existing software to legacy status. Generating software through reusing legacy systems has been a primary solution and software re-engineering has the potential to improve software productivity and quality across the entire software life cycle. The classical re-engineering technology starts at the level of program source code which is the most or only reliable information on a legacy system. The program specification derived from legacy source code will then facilitate the migration of legacy systems in the subsequent forward engineering steps. A recent research trend in re-engineering area carries this idea further and moves into model driven perspective that the specification is presented with models. The thesis focuses on engaging model technology to modernise legacy systems. A unified approach, REMOST (Re-Engineering through MOdel conStruction and Transformation), is proposed in the context of Model Driven Architecture (MDA). The theoretical foundation is the construction of a WSL-based Modelling Language, known as WML, which is an extension of WSL (Wide Spectrum Language). WML is defined to provide a spectrum of models for the system re-engineering, including Common Modelling Language (CML), Architecture Description Language (ADL) and Domain Specific Modelling Language (DSML). 9rtetaWML is designed for model transformation, providing query facilities, action primitives and metrics functions. A set of transformation rules are defined in 9rtetaWML to conduct system abstraction and refactoring. Model transformation for unifying WML and UML is also provided, which can bridge the legacy systems to MDA. The architecture and working flow of the REMOST approach are proposed and a prototype tool environment is developed for testing the approach. A number of case studies are used for experiments with the approach and the prototype tool, which show that the proposed approach is feasible and promising in its domain. Conclusion is drawn based on analysis and further research directions are also discussed

A COMMITMENT-BASED REFERENCE ONTOLOGY FOR SERVICE: HARMONIZING SERVICE PERSPECTIVES

Nowadays, the notion of service has been widely adopted in the practice of economic sectors (e.g., Service, Manufacturing, and Extractive sectors), as well as, in the research focus of various disciplines (e.g., Marketing, Business, and Computer Science). Due to that, a number of research initiatives (e.g., service ontologies, conceptual models, and theories) have tried to understand and characterize the complex notion of service. However, due to particular views of these disciplines and economic sectors, a number of different characterizations of service (e.g., service as interaction, service as co-creation of value, and service as capability / manifestation of competence, among others) have been proposed. The existence of these various non-harmonized characterizations, and the focus on a terminological debate about the service concept, instead of about the service phenomena from a broad perspective, make the establishment of a unified body of knowledge for service difficult. This limitation impacts, e.g., the establishment of unified conceptualization for supporting the smooth alignment between Business and IT views in service-oriented enterprise architecture (SoEA), and the design and usage of service modeling languages. In this thesis we define a theoretical foundation for service based on the notion of service commitment and claims as basic elements in the characterization of service relations along service life-cycle phases (service offer, service negotiation, and service delivery). As discussed in this work, this theoretical foundation is capable of harmonizing a number of service perspectives found in the literature. Such theoretical foundation is specified in a well-founded core reference ontology, named UFO-S, which was designed by adopting a sound ontological engineering apparatus (mainly, a well-founded ontology representation language, OntoUML, and approaches of model verification and model validation). As a kind of theory, UFO-S was applied in the analysis of SoEA structuring principles in order to define a commitment-based SoEA view, which remarks social aspects inherent in service relations usually underexplored in widely adopted service-oriented approaches (such as SOA-RM by OASIS, ITIL, and ArchiMate). Based on this, UFO-S was also applied in an ontological analysis of service modeling at ArchiMates Business layer. Such ontological analysis showed some limitations concerned to semantic ambiguity and lack of expressiveness for representing service offerings (and type thereof) and service agreements in SoEA. In order to address these limitations, three service modeling patterns (service offering type pattern, service offering pattern, and service agreement pattern) were proposed taking as basis UFO-S. The usefulness of these patterns for addressing these limitations was evidentiated by means of an empirical evaluation. Finally, we can say that, beyond offering a broad and well-founded theoretical foundation for service able to harmonize service perspectives, UFO-S presented benefits as a reference model in the analysis of SoEA structuring principles, and in the (re)design of service modeling languages

Adaptations dynamiques au contexte en informatique ambiante : propriétés logiques et temporelles

In ubiquitous computing, applications are built as a collaboration of computerized and communicating objects called devices. Because these devices can be mobile or subject to failures, this infrastructure evolves dynamically and unpredictably. Thus, to fit seamlessly into their environment and to provide the functionalities expected by users which are often more sustainable than the environment, applications must dynamically adapt to these changes. Each of these variable phenomena pursues its own dynamic. The challenge offered to adaptation mechanisms is to be able to consider them, with suitable dynamics.For this purpose, we propose an architectural model and an adaptation mechanism. The architectural model is based on four levels organized hierarchically according to their complexity and to the dynamics they can offer. We combine to this architectural model an adaptation mechanism. Based on the separation of concerns principle, our mechanism allows us to consider the variability of the system. Due to the unpredictability of the environment, the sets of adaptations that will be deployed by the upper levels of the architecture may not have been anticipated at design time. Also, thanks to some logical and temporal properties, these adaptations can be composed in non-anticipated way and with appropriate response time. The proposed mechanism, called cascaded aspects, is implemented using Aspects of Assembly and the WComp execution platform.En informatique ambiante, les applications sont construites en faisant interagir entre eux des objets informatisés et communicants appelés dispositifs. Parce que ces dispositifs peuvent être mobiles ou subir des pannes, cette infrastructure évolue dynamiquement et de manière imprévisible. Aussi, pour s’insérer de manière transparente dans leur environnement et fournir les fonctionnalités attendues par les utilisateurs, bien souvent plus pérennes que l’environnement sur lequel elles reposent, les applications doivent s’adapter dynamiquement à ces évolutions. Ces phénomènes variables poursuivant leur propre dynamique, le défi proposé aux mécanismes d’adaptation est d’être capable de les prendre encompte, avec une dynamique adaptée à chacun d’entre eux.Dans cette optique, nous proposons un modèle architectural ainsi qu’un mécanisme d’adaptation. Le modèle architectural repose sur quatre niveaux organisés hiérarchiquement en fonction de leur complexité et de la dynamique qu’ils peuvent offrir. Nous lui associons un mécanisme d’adaptation qui, à partir du principe de séparation des préoccupations permet d’exprimer la variabilité du système. En raison de l’imprévisibilité de l’environnement, les ensembles d’adaptations qui seront déployées par les niveaux supérieurs de l’architecture ne peuvent pas nécessairement être anticipés à la conception. Aussi, grâce à un ensemble de propriétés logiques et temporelles, ces adaptations peuvent être composées de manière non-anticipée dans des temps de réponse adaptés. Le mécanisme d’adaptation proposé, appelé cascade d’aspects, est expérimenté en se basant sur les Aspects d’Assemblages et la plateforme d’exécution WComp