363 research outputs found

    XRound : A reversible template language and its application in model-based security analysis

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    Successful analysis of the models used in Model-Driven Development requires the ability to synthesise the results of analysis and automatically integrate these results with the models themselves. This paper presents a reversible template language called XRound which supports round-trip transformations between models and the logic used to encode system properties. A template processor that supports the language is described, and the use of the template language is illustrated by its application in an analysis workbench, designed to support analysis of security properties of UML and MOF-based models. As a result of using reversible templates, it is possible to seamlessly and automatically integrate the results of a security analysis with a model. (C) 2008 Elsevier B.V. All rights reserved

    Roundtrip engineering of NoSQL databases

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    International audienceIn this article we present a framework describing a roundtrip engineering process for NoSQLdatabase systems. This framework, based on the Model Driven Engineering approach, is composed of aknowledge base guiding the roundtrip process. Starting from a roundtrip generic scenario, we proposeseveral roundtrip scenarios combining forward and reverse engineering processes. We illustrate ourapproach with an example related to a property graph database. The illustrative scenario consists ofsuccessive steps of model enrichment combined with forward and reverse engineering processes. Futureresearch will consist in designing and implementing the main components of the knowledge base

    FV-RAD : a practical framework for rapid application development

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    Estágio realizado na OPT-Optimização e Planeamento de Transportes, S.ATese de mestrado integrado. Engenharia Informática e Computação. Faculdade de Engenharia. Universidade do Porto. 200

    Support for Bidirectional Model-to-Text Transformations

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    In recent years, model-driven approaches and processes have established themselves as pragmatic and feasible solutions with tangible advantages. Transformations play a central role in any model-driven solution and, as interest in textual modelling grows, providing concepts and tools for supporting a high-level and declarative specification of bidirectional model-to-text transformations becomes a vital area of research. Our paper identifies important areas and scenarios for model-to-text transformations that are not or only partially supported by currently existing solutions. Based on the requirements of a real-world case study, we introduce a new concept that has been inspired by a successful bidirectional model-to-model transformation approach: Triple Graph Grammars

    From BPMN Models to Labelled Property Graphs

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    There\u27s a growing interest in leveraging the structured and formal nature of business process modeling languages in order to make them available not only for human analysis but also to machine-readable knowledge representation. Standard serializations of the past were predominantly XML based, with some of them seemingly discontinued, e.g., XPDL after the dissolution of the Workflow Management Coalition. Recent research has been investigating the interplay between knowledge representation and business process modeling, with the focus typically placed on standards such as RDF and OWL. In this paper we introduce a converter that translates the standards-compliant BPMN XML format to Neo4J labelled property graphs (LPG) thus providing an alternative to both traditional XML-based serialization and to more recent experimental RDF solutions, while ensuring conceptual alignment with the standard serialization of BPMN 2.0. A demonstrator was built to highlight the benefits of having such a parser and the completeness of coverage for BPMN models. The proposal facilitates graph-based processing of business process models in a knowledge intensive context, where procedural knowledge available as BPMN diagrams must be exposed to machines and LPG-driven applications

    Early aspects: aspect-oriented requirements engineering and architecture design

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    This paper reports on the third Early Aspects: Aspect-Oriented Requirements Engineering and Architecture Design Workshop, which has been held in Lancaster, UK, on March 21, 2004. The workshop included a presentation session and working sessions in which the particular topics on early aspects were discussed. The primary goal of the workshop was to focus on challenges to defining methodical software development processes for aspects from early on in the software life cycle and explore the potential of proposed methods and techniques to scale up to industrial applications

    A Model Driven Approach to Model Transformations

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    The OMG's Model Driven Architecture (MDA) initiative has been the focus of much attention in both academia and industry, due to its promise of more rapid and consistent software development through the increased use of models. In order for MDA to reach its full potential, the ability to manipulate and transform models { most obviously from the Platform Independent Model (PIM) to the Platform Specific Models (PSM) { is vital. Recognizing this need, the OMG issued a Request For Proposals (RFP) largely concerned with finding a suitable mechanism for trans- forming models. This paper outlines the relevant background material, summarizes the approach taken by the QVT-Partners (to whom the authors belong), presents a non-trivial example using the QVT-Partners approach, and finally sketches out what the future holds for model transformations

    Composite Gel Polymer Electrolytes for Extended Cyclability of Lithium-Oxygen Batteries

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    In lithium-oxygen (Li-O2) batteries, addressing challenges like electrode degradation, cell stability and electrolyte decomposition are key to creating more practical applications. Despite many attempts to minimize anode oxidation and cathode byproduct formation, the electrolyte remains the leading source for rapid capacity fading and poor cyclability in Li-O2batteries. Understanding the loss of functionality in electrolytes, carbon nanotube (CNT) fillers and redox mediators (RM), during cycling within Li-O2battery systems, could be the solution to prolonging battery lifetime. Determining the efficiency of these battery components and additives will push the medium towards lifelong, rechargeable and safe battery configurations. Composite gel polymer electrolytes (cGPE) consisting of an acrylate-based polymer, tetraglyme based electrolyte, and glass microfibers provided a stable membrane for a dual-enhancement system consisting of (1) CNT loaded onto a porous carbon cloth at the cathode for oxygen inlet and (2) a lithium-iodide (LiI) RM to oxidize the Li-O2battery during charge, thus reducing overpotential. Combining the battery performance improvements of the highly conductive CNT fillers, charge mediation of LiI RM, modified cycle capacities (500 mAhg-1to 100 mAhg-1) and ionic transport properties of glass microfibers, resulted in a superior 1763% increase in charge/discharge cyclability (CCD) for maximized cGPE (423 cycles) cells, when compared to the control GPE (24 cycles) cell. Results using in-situ electrochemical impedance spectroscopy (EIS), Raman spectroscopy and cyclic voltammetry (CV) revealed that the source of the improvement was the rate of lithium carbonate formation being reduced on the surface of the cathode. Operation using thin, multi-layered concentric CNT fillers with LiI RM decreased LixRCO3 (R- carbon and hydrogen groups) formation rates due to the decreased electrolyte and cathode decomposition rates. This stabilization during cycling helped prolong battery life to 401 cycles (in comparison to 75 cycles from other CNTs) by maintaining lower charge potential, since higher potentials have been associated with rapid cell deterioration. In this dissertation, Li-O2battery cyclability was extended by improving ionic transportation in the electrolyte, and charge mediation and conductivity in the cathode from LiI RM and CNT fillers, respectively. These batteries provide a wealth of application primarily in electric vehicles, grid and consumer electronics

    Testing the nature of dark compact objects: a status report

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    Very compact objects probe extreme gravitational fields and may be the key to understand outstanding puzzles in fundamental physics. These include the nature of dark matter, the fate of spacetime singularities, or the loss of unitarity in Hawking evaporation. The standard astrophysical description of collapsing objects tells us that massive, dark and compact objects are black holes. Any observation suggesting otherwise would be an indication of beyond-the-standard-model physics. Null results strengthen and quantify the Kerr black hole paradigm. The advent of gravitational-wave astronomy and precise measurements with very long baseline interferometry allow one to finally probe into such foundational issues. We overview the physics of exotic dark compact objects and their observational status, including the observational evidence for black holes with current and future experiments.Comment: 76 pages + references. Invited review article for Living Reviews in Relativity. v3: Overall improvements and references added, a few typos corrected. Version to appear in LR
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