629 research outputs found

    Metamodeling the enhanced entity-relationship model

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    [EN] A metamodel provides an abstract syntax to distinguish between valid and invalid models. That is, a metamodel is as useful for a modeling language as a grammar is for a programming language. In this context, although the Enhanced Entity-Relationship (EER) Model is the de facto standard modeling language for database conceptual design, to the best of our knowledge, there are only two proposals of EER metamodels, which do not provide a full support to Chen s notation. Furthermore, neither a discussion about the engineering used for specifying these metamodels is presented nor a comparative analysis among them is made. With the aim at overcoming these drawbacks, we show a detailed and practical view of how to formalize the EER Model by means of a metamodel that (i) covers all elements of the Chen s notation, (ii) defines well-formedness rules needed for creating syntactically correct EER schemas, and (iii) can be used as a starting point to create Computer Aided Software Engineering (CASE) tools for EER modeling, interchange metadata among these tools, perform automatic SQL/DDL code generation, and/or extend (or reuse part of) the EER Model. In order to show the feasibility, expressiveness, and usefulness of our metamodel (named EERMM), we have developed a CASE tool (named EERCASE), which has been tested with a practical example that covers all EER constructors, confirming that our metamodel is feasible, useful, more expressive than related ones and correctly defined. Moreover, we analyze our work against the related ones and present our final remarks.Fidalgo, RN.; Alves, E.; España Cubillo, S.; Castro, J.; Pastor López, O. (2013). Metamodeling the enhanced entity-relationship model. Journal of Information and Data Management. 4(3):406-420. http://hdl.handle.net/10251/47949S4064204

    Manufacturability Analysis of Thermally-Enhanced Polymer Composite Heat Exchangers

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    Thermally-enhanced polymer composite heat exchangers are an attractive alternative for applications such as the use of seawater as a cooling medium and other corrosive environments that traditionally use expensive exotic metallic alloys, but a number of manufacturing challenges exist. The goal of this thesis is to develop an understanding of the manufacturing feasibility, in particular mold filling and fiber orientation, of utilizing thermally-enhanced polymer composites and injection molding to manufacture polymer heat exchangers. To best predict mold filling feasibility, this thesis proposes developing an explicit construction of the boundary, represented as a surface based on the parameter space, which separates the feasible and infeasible design space. The feasibility boundary for injection molding in terms of the design parameters is quite complex due to the highly nonlinear process physics, which, consequently, makes molding simulation computationally intensive and time consuming. This thesis presents a new approach for the explicit construction of a moldability-based feasibility boundary based on intelligent Design of Experiments and adaptive control techniques to minimize the number or computation experiments needed to build an accurate model of the feasibility boundary. Additionally, to improve the flexibility of the mold filling prediction framework to changes in overall heat exchanger design, a model simplification approach is presented to predict mold filling for general finned-plate designs by determining an equivalent flat plate representation and utilizing a developed flat plate mold filling metamodel to estimate mold filling. Finally, a fiber orientation measurement methodology is presented for experimentally determining fiber orientation behavior for sample heat exchanger geometries that develops both a local and global understanding of the fiber orientation behavior and compares thesis findings to simulation predictions. The work presented in this thesis significantly advances the understanding of manufacturability considerations for utilizing thermally-enhanced polymer composites in heat exchanger applications and is useful in design exploration, optimization, and decision-making approaches

    NOSTROMO: Lessons learned, conclusions and way forward

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    This White Paper sets out to explain the value that metamodelling can bring to air traffic management (ATM) research. It will define metamodelling and explore what it can, and cannot, do. The reader is assumed to have basic knowledge of SESAR: the Single European Sky ATM Research project. An important element of SESAR, as the technological pillar of the Single European Sky initiative, is to bring about improvements, as measured through specific key performance indicators (KPIs), and as implemented by a series of so-called SESAR 'Solutions'. These 'Solutions' are new or improved operational procedures or technologies, designed to meet operational and performance improvements described in the European ATM Master Plan

    Achieving Business Process Model Interoperability Using Metamodels and Ontologies

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    NOSTROMO: Lessons learned, conclusions and way forward

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    This White Paper sets out to explain the value that metamodelling can bring to air traffic management (ATM) research. It will define metamodelling and explore what it can, and cannot, do. The reader is assumed to have basic knowledge of SESAR: the Single European Sky ATM Research project. An important element of SESAR, as the technological pillar of the Single European Sky initiative, is to bring about improvements, as measured through specific key performance indicators (KPIs), and as implemented by a series of so-called SESAR 'Solutions'. These 'Solutions' are new or improved operational procedures or technologies, designed to meet operational and performance improvements described in the European ATM Master Plan.Comment: White Paper of the NOSTROMO, an exploratory research project funded by the SESAR Joint Undertaking (SJU) under the European Union's Horizon 2020 research and innovation programm

    NOSTROMO - D1.2 - Final Project Results Report

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    The main objective of the NOSTROMO project has been to develop, demonstrate and evaluate an innovative modelling approach for the rigorous and comprehensive assessment of the performance impact of future ATM concepts and solutions at ECAC network level. This approach brings together the ability of bottom-up microscopic models to capture emergent behaviour and interdependencies between different solutions with the level of tractability and interpretability required to effectively support decision-making. This report provides a summary of NOSTROMO accomplishments and contributions to the SESAR Programme. It gathers technical lessons learned and concludes proposing further developments to facilitate the use of the NOSTROMO methodology in the future SESAR 3 Programme

    Analysis of requirements incompleteness using metamodel specification

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    Incompleteness of requirements has been treated as a huge challenge in software development projects. Since it is hard to obtain all required information before software design and implementation starts, the software modeling process may start with an incomplete requirements specification. In order to help analyzing the incompleteness in requirements, I propose a metamodel approach for detecting the missing requirements that are needed for constructing conceptual models for a software system, and implement it in MetaEdit+. The detected missing information in a conceptual model is reported in natural language, which is easy to understand. Furthermore, the conceptual modelers can identify the potential problems indicated by the report to analyze and update the model. The contribution of my thesis is twofold, i.e. analyzing the link between business rules and the ER models, and implementing a method to automatically detect and show the incompleteness in ER models

    MODELING REQUIREMENTS FOR FUTURE: ISSUES AND IMPLEMENTATION CONSIDERATIONS

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    In this paper, we discuss some requirements for future CASE (Computer Aided Software/Systems Engineering) environments. These requirements include increased modifiability and flexibility as well as support for task and agent models. We claim that they can only be addressed by developing more powerful representation and modeling techniques. As a possible basis for a modeling technique, we propose the GOPRR (Graph-Object-Property-Relationship-Role) data model, which addresses some of these requirements. In addition, a general information architecture for a future CASE environment is outlined. It includes three kinds of models for methodology specification: meta-datamodels, activity (task) models, and agent models. These models are defined using the GOPRR model with some additional concepts for IS development process and agent participation
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