788 research outputs found

    Requirements traceability in model-driven development: Applying model and transformation conformance

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    The variety of design artifacts (models) produced in a model-driven design process results in an intricate relationship between requirements and the various models. This paper proposes a methodological framework that simplifies management of this relationship, which helps in assessing the quality of models, realizations and transformation specifications. Our framework is a basis for understanding requirements traceability in model-driven development, as well as for the design of tools that support requirements traceability in model-driven development processes. We propose a notion of conformance between application models which reduces the effort needed for assessment activities. We discuss how this notion of conformance can be integrated with model transformations

    Abstract Platform and Transformations for Model-Driven Service-Oriented Development

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    In this paper, we discuss the use of abstract platforms and transformation for designing applications according to the principles of the service-oriented architecture. We illustrate our approach by discussing the use of the service discovery pattern at a platform-independent design level. We show how a trader service can be specified at a high-level of abstraction and incorporated in an abstract platform for service-oriented development. Designers can then build platform-independent models of applications by composing application parts with this abstract platform. Application parts can use the trader service to publish and discover service offers. We discuss how the abstract platform can be realized into two target platforms, namely Web Services (with UDDI) and CORBA (with the OMG trader)

    Costs and benefits of multiple levels of models in MDA development

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    In Model-Driven Architecture (MDA) development, models of a distributed application are carefully defined so as to remain stable in face of changes in technology platforms. As we have argued previously in [1, 3], models in MDA can be organized into different levels of platformindependence. In this paper, we analyze the costs and benefits of maintaining separate levels of models with transformations between these levels. We argue that the number of levels of models and the degree of automation of transformations between these levels depend on a number of design goals to be balanced, including those of maximizing the efficiency of the design process and maximizing the reusability of models and transformations

    The role of the service concept in model-driven applications development

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    This paper identifies two paradigms that have influenced the design of distributed applications: the middleware-centred and the protocol-centred paradigm, and proposes a combined use of these two paradigms. This combined use incorporates major benefits from both paradigms: the ability to reuse middleware infrastructures and the ability to treat distributed coordination aspects as a separate object of design through the use of the service concept. A careful consideration of the service concept, and its recursive application, allows us to define an appropriate and precise notion of platform-independence that suits the needs of model-driven middleware application development

    Quantum Yang-Mills gravity in flat space-time and effective curved space-time for motions of classical objects

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    Yang-Mills gravity with translational gauge group T(4) in flat space-time implies a simple self-coupling of gravitons and a truly conserved energy-momentum tensor. Its consistency with experiments crucially depends on an interesting property that an `effective Riemannian metric tensor' emerges in and only in the geometric-optics limit of the photon and particle wave equations. We obtain Feynman rules for a coupled graviton-fermion system, including a general graviton propagator with two gauge parameters and the interaction of ghost particles. The equation of motion of macroscopic objects, as an N-body system, is demonstrated as the geometric-optics limit of the fermion wave equation. We discuss a relativistic Hamilton-Jacobi equation with an `effective Riemann metric tensor' for the classical particles.Comment: 20 pages, to be published in "The European Physical Journal - Plus"(2011). The final publication is available at http://www.epj.or

    Extensive beef cattle production in Portugal

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    Portugal, located in the Mediterranean region, one of the "Hot Spot" of the planet, has a huge variability in terms of topography, soils, climate, agriculture, traditions, resulting in a high diversity of animal genetic resources, represented by 15 native cattle breeds, most of them threatened. A significant percentage of extensive beef cattle production in Portugal is based on the use of animals, differing from north to south region, with good maternal aptitude, hardiness, a low growth performance and exceptional adaptation to the environment where they live, and especially to the local feed, naturally produced. In the north of the country and the Azores, dairy breeds predominate, while in the south beef breeds are most prevalent. Portugal is not self-sufficient in beef production, however it is possible to appreciate an market for beef produced by indigenous breeds from extensive and organic production systems. Beef from indigenous breeds is considered to be a high quality product, mainly because of the superior taste and structure of the meat resulting from the production system: slow growth rate and type of vegetation consumed. This product differentiation has allowed the enlargement of small niche markets and has led to an increase in the value of meat with a Protected Designation of Origin (PDO) or with organic beef. Since portuguese agriculture cannot compete on quantity or production cost with other competitors, differentiation and quality seem to be the alternatives that may stimulate rural activities in Less Favoured Areas (LFAs) and create a regional added value able to contribute to sustainable development. Extensive animal production systems can be an important component of environmental and landscape protection, as well as contribute to the decrease of the human, physical desertification of our rural areas and animal genetic resources

    Traveling length and minimal traveling time for flow through percolation networks with long-range spatial correlations

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    We study the distributions of traveling length l and minimal traveling time t through two-dimensional percolation porous media characterized by long-range spatial correlations. We model the dynamics of fluid displacement by the convective movement of tracer particles driven by a pressure difference between two fixed sites (''wells'') separated by Euclidean distance r. For strongly correlated pore networks at criticality, we find that the probability distribution functions P(l) and P(t) follow the same scaling Ansatz originally proposed for the uncorrelated case, but with quite different scaling exponents. We relate these changes in dynamical behavior to the main morphological difference between correlated and uncorrelated clusters, namely, the compactness of their backbones. Our simulations reveal that the dynamical scaling exponents for correlated geometries take values intermediate between the uncorrelated and homogeneous limiting cases

    Ultrassonografia duplex Doppler transcraniana em cĂŁes com hidrocefalia

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    Transcranial duplex Doppler ultrasound was performed in 32 conscious dogs presenting ventriculomegaly detected in B-mode, obtaining measures of lateral ventricles and resistance parameters of main cerebral arteries before and after 30 days of clinical treatment. The animals were distributed divided in two groups: group 1, dogs that presented remission or decrease of the neurological signs of the disease after clinical therapy; and group 2, dogs that displayed worsening of the neurological signs or clinical stability. The data were all presented in tables and were submitted to paired t test and to logistic regression models to evaluate the influence of the RI reduction on both groups. There was no significant influence of the variables in the B-mode. After the treatment, the mean resistive index (RI) was significantly lower for the group that presented clinical improvement. There was no significant difference of the mean RI reduction for the same artery when the right and left sides were compared. It could be concluded that transcranial duplex Doppler ultrasound is a method of cerebral hemodynamic assessment able to monitor more precisely the treatment of hydrocephalus in dogs and verify the responses.Foi realizada a ultrassonografia duplex Doppler transcraniana em 32 cĂŁes, conscientes, que apresentavam ventriculomegalia previamente detectada ao exame modo-B, para obter as medidas dos ventrĂ­culos laterais e os parĂąmetros de resistĂȘncia das artĂ©rias cerebrais antes e depois de 30 dias de tratamento clĂ­nico. Os animais foram distribuĂ­dos em dois grupos: 1 - formado por cĂŁes que apresentaram remissĂŁo ou diminuição dos sinais clĂ­nicos apĂłs tratamento; 2 - por cĂŁes que apresentaram piora dos sinais neurolĂłgicos ou estabilidade do quadro clĂ­nico. Todos os dados foram dispostos em tabelas e submetidos ao teste t pareado e a modelos de regressĂŁo logĂ­stica para avaliar a influĂȘncia da redução do Ă­ndice de resistividade (IR). NĂŁo foi observada influĂȘncia das variĂĄveis em modo-B. ApĂłs o tratamento, a mĂ©dia do IR foi significantemente menor para o grupo que apresentou melhora clĂ­nica; nĂŁo houve diferença significativa da mĂ©dia de redução do IR para a mesma artĂ©ria quando comparados os lados direito e esquerdo. Concluiu-se que o duplex Doppler transcraniano Ă© um mĂ©todos de avaliação hemodinĂąmica capaz de monitorar mais precisamente o tratamento da hidrocefalia em cĂŁes e verificar a resposta dos pacientes

    Infection By The Human Papillomavirus In Teenagers Sexually Active: Clinic And Subclinic Manifestations.

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    This research studies the association of the cervical condyloma with the intraepithelial neoplasia, during sex activity, pregnancy, diagnose methods, cytology and colposcopy in teenagers. The objective of this research is to study the propaedeutics for the uterine coli condyloma diagnose in a group of teenagers. For this purpose, we have studied 131 teenagers sexually active with ages between 14 and 19 years and presenting histologically confirmed uterine coli condyloma. Association with intraepithelial neoplasia, sexual activity duration, method of diagnose, pregnancy analysis, cytology and colposcopy results and association with vulva and vagina injuries were evaluated. The high association rate with condyloma and intraepithelial neoplasia after a short time of sexual activity and the none presence of macroscopic warts in the genital organs in 80% of cases presenting cervical condyloma, demonstrate that: a more careful investigation with colposcopy and biopsy of the inferior genitals of the women-teenagers sexually active is needed, when presenting modified cervical cytology.113494895
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