João Paulo A. Almeida

Transparent dynamic reconfiguration for CORBA

Distributed systems with high availability requirements have to support some form of dynamic reconfiguration. This means that they must provide the ability to be maintained or upgraded without being taken off-line. Building a distributed system that allows dynamic reconfiguration is very intrusive to the overall design of the system, and generally requires special skills from both the client and server side application developers. There is an opportunity to provide support for dynamic reconfiguration at the object middleware level of distributed systems, and create a dynamic reconfiguration transparency to application developers. We propose a Dynamic Reconfiguration Service for CORBA that allows the reconfiguration of a running system with maximum transparency for both client and server side developers. We describe the architecture, a prototype implementation, and some preliminary test results.

Towards Ontological Foundations for the Conceptual Modeling of Events

In recent years, there has been a growing interest in the application of foundational ontologies, i.e., formal ontological theories in the philosophical sense, to provide a theoretically sound foundation for improving the theory and practice of conceptual modeling. In this paper, we present advances on our research on the ontological foundations of conceptual modeling by addressing the concept of events. We present a foundational ontology of events termed UFO-B together with its axiomatization in first-order logic. Moreover, we report on an implementation of UFO-B using the computational logic language Alloy, and discuss its consistency, validation and possible uses.

On the notion of abstract platform in MDA development

Although platform-independence is a central property in MDA models, the study of platform-independence has been largely overlooked in MDA. As a consequence, there is a lack of guidelines to select abstraction criteria and modelling concepts for platform-independent design. In addition, there is little methodological support to distinguish between platform-independent and platform-specific concerns, which could be detrimental to the beneficial exploitation of the PIM-PSM separation-of-concerns adopted by MDA. This work is an attempt towards clarifying the notion of platform-independent modelling in MDA development. We argue that each level of platform-independence must be accompanied by the identification of an abstract platform. An abstract platform is determined by the platform characteristics that are relevant for applications at a certain level of platform-independence, and must be established by balancing various design goals. We present some methodological principles for abstract platform design, which forms a basis for defining requirements for design languages intended to support platform-independent design. Since our methodological framework is based on the notion of abstract platform, we pay particular attention to the definition of abstract platforms and the language requirements to specify abstract platforms. We discuss how the concept of abstract platform relates to UML.

Situations in Conceptual Modeling of Context

In previous work, we have defined conceptual foundations that can be beneficially used in context modeling. These conceptual foundations include the separation of entity and context, and the characterization of context as either Intrinsic or Relational. This paper aims at extending this approach by introducing the ontological concept of Situation as means of composing the elements of our ontology (entities, intrinsic and relational contexts) to model particular states of affairs of interest. Our concepts have been inspired by and aligned with conceptual theories from the fields of philosophy and cognitive sciences.

Empowering enterprises through next-generation enterprise computing

Enterprise computing is concerned with exploiting interconnected computers to improve the efficiency and effectiveness of larger companies. Such companies form business organizations that manage various sorts of information, used by disparate groups of people, who are situated at different geographical locations. This motivates the use of computer-based information systems, not only to reduce costs and increase productivity, but also to enable novel business models. As a result of the importance of enterprise computing to business organizations, information systems have been massively deployed. In order to cope with legacy and heterogeneity problems and consequently with lack of interoperability, considerable research efforts have been spent on integration of otherwise isolated systems either within the scope of a single organization or across organizational boundaries. This has spawned a number of important developments, including Enterprise Application Integration (EAI), Business Process Management (BPM), Business-to-Business integration (B2Bi), and, more recently, Service Oriented Architecture (SOA). In this editorial we reflect on current and future enterprise computing developments that would further empower enterprises. We do this inspired by the articles in this special issue, which are revised versions of selected best papers of the 13th IEEE International EDOC Conference (EDOC 2009), “The Enterprise Computing Conference”, held on 1-4 September 2009 in Auckland, New Zealand. In addition, we discuss a new technology-driven paradigm that may have considerable impact on enterprise computing and hence on the future of enterprises.

Transforming OntoUML into Alloy: towards conceptual model validation using a lightweight formal method

While conceptual modeling is strongly related to the final quality of the software product, conceptual modeling itself remains a challenging activity. In particular, modelers must ensure that conceptual models properly formalize their intended conceptualization of a domain. This paper proposes an approach to facilitate the validation process of conceptual models defined in OntoUML by transforming these models into specifications in the logic-based language Alloy and using its analyzer to generate instances of the model and assertion counter-examples. By allowing the observation of sequences of snapshots of model instances, the dynamics of object creation, classification, association and destruction are revealed. This confronts the modeler with the implications of modeling choices and allows them to uncover mistakes or gain confidence in the quality of conceptual models.

Requirements engineering based on business process models: A case study

This paper reports a study in which business process modelling was regarded as a useful tool for requirements engineering. We have used business process models as a starting point to derive alternative sets of requirements for a process-oriented system. These alternative sets capture different decisions regarding the intended “level of automation” for the various activities in a business process. The approach is demonstrated in a case study which consists of the development of a real system to manage processes in a Human Resources (HR) Department of a large organization. We use a requirements specification that was previously obtained through what we characterize as a “conventional” requirements engineering technique and we compare it with the requirements specifications derived from the business process model. We discuss the impact of the use of business process models in the completeness, correctness, consistency and traceability of requirements in the case study.

Model-driven development of context-aware services

In this paper, we define a model-driven design trajectory for context-aware services consisting of three levels of models with different degrees of abstraction and platform independence. The models at the highest level of platform independence describe the behaviour of a context-aware service and its environment from an integrated perspective. The models at the intermediate level describe abstract components, which realize the context-aware service in terms of a service-oriented abstract platform. At the lowest level, the realization of a context-aware service is described in terms of specific target technologies, such as Web Services, BPEL and Parlay technologies. Our approach allows service designers to concentrate their efforts on the services they intend to create and offer, by facilitating the handling of context information and auto-mating design steps through model transformation. In addition, our approach enables the reuse of platform-independent models for different target platforms.

Modeling resources and capabilities in enterprise architecture

The importance of capabilities and resources for portfolio management and business strategy has been recognized in the management literature. Despite that, little attention has been given to integrate the notions of capabilities and resources in enterprise architecture descriptions. One notable exception is a recent proposal to extend the ArchiMate framework and language to include capability and resources and thus improve ArchiMates coverage of portfolio management. This paper presents an ontological analysis of the concepts introduced in that proposal, focusing in particular on the resource, capability and competence concepts. We provide an account for these concepts in terms of the Unified Foundational Ontology (UFO). The analysis allows us to identify semantic issues in the proposal and suggests well-founded recommendations for improvements. We revise the proposed metamodel in order to address the identified problems, thereby improving the semantic clarity and usefulness of the proposed language extension. Two real-world cases are modeled with the resulting metamodel to show the applicability of the constructs and relations in an industrial setting. We present an ontological analysis of resource, capability and competence for EA.We found 13 issues on the original proposal with the ontological analysis.We refactor the original metamodel to address the identified problems.We present two use cases using the improved extension.Our recommendations should lead to improved resource and capability oversight.

Towards ontological foundations for conceptual modeling: The unified foundational ontology (UFO) story

This paper describes a long-term research program on developing ontological foundations for conceptual modeling. This program, organized around the theoretical background of the foundational ontology UFO (Unified Foundational Ontol- ogy), aims at developing theories, methodologies and engineering tools with the goal of advancing conceptual modeling as a theoretically sound discipline but also one that has concrete and measurable practical implications. The paper describes the historical context in which UFO was conceived, briefly discusses its stratified organization, and reports on a number of applica- tions of this foundational ontology over more than a decade. In particular, it discusses the most successful application of UFO, namely, the development of the conceptual modeling language OntoUML. The paper also discusses a number of methodological and computational tools, which have been developed over the years to support the OntoUML community. Examples of these methodological tools include ontological patterns and anti-patterns; examples of these computational tools include automated support for pattern-based model construction, formal model verification, formal model validation via visual simulation, model verbalization, code generation and anti-pattern detection and rectification. In addition, the paper reports on a variety of appli- cations in which the language as well as its associated tools have been employed to engineer models in several institutional contexts and domains. Finally, it reflects on some of these lessons learned by observing how OntoUML has been actually used in practice by its community and on how these have influenced both the evolution of the language as well as the advancement of some of the core ontological notions in UFO.