20,826 research outputs found

    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 RM-ODP computational viewpoint concepts in the MDA approach

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    An MDA design approach should be able to accommodate designs at different levels of platform-independence. We have proposed a design approach previously (in [2]), which allows these levels to be identified. An important feature of this approach is the notion of 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 considering various design goals. In this paper, we define a framework that makes it possible to use RM-ODP concepts in our MDA design approach. This framework allows a recursive application of the computational viewpoint at different levels of platform-independence. This is obtained by equating the RM-ODP notion of infrastructure to our notion of abstract platform

    Homophobia in the contemporary Russia: a queer postcolonial approach

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    This thesis aims to investigate the phenomenon of contemporary homophobia in Russia as mutually inseparable foreign and domestic constitutive phenomenon as part of the complex interplay of Russian-West international relations. For this task, the thesis analyses homophobia through the lens of postcolonial framework and the queer critiques on notions of sovereignty as construction of sovereign knowable subject. The advantage of the postcolonial framework of analysis is precisely the possibility of a broad intersystem understanding of the phenomenon aligning domestic and systemic levels. The postcolonial is also particularly fruitful framework for case studies which deals inherently with the challenge to allow sufficient degree of generalisation that allows further comparisons and pays enough attention to the specific contextual location, postcolonial framework has enough degree of generalisation due to emphasis on the structure combined to sensitivity to the local context due to valorisation of local subject. In this context Russia should be seen as part of the postcolonial space, despite of fact Russia has never been formally occupied by any Western nation-state, Russia colonised itself on behalf of Europe in a self-orientalist process, since the Tsarist times Russia has an ambiguous relation with the West of being mutually othering and being othered by Europe. The analysis of public Russian discourses on LGBT issues in the last 15 years, surveys legal texts and NGO reports about the situation of mass persecution of LGBT people in Chechnya suggest that the foundations of contemporary homophobia are constituted in this complex dialectical interplay between subaltern and imperial aspects of Russian international relations. This situation of Russia as a former superpower in the recent past and then a state rendered as subaltern in the present in a Western hegemonic order leads to a perception of threat on its sovereignty, one key manifestation of this anxious with sovereignty is homophobia which represents to Russia not only a powerful symbol of negation of Western liberal normative order but also an attempt to subvert the chrononormative narrative of evolutionary development in which the West sits as the last point of evolution by setting the West as decadent and degenerated because of acceptance of homosexuality and Russia as the real guardian of the real European values, now lost in the real Europe.http://www.ester.ee/record=b5148211*es

    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

    Interaction systems design and the protocol- and middleware-centred paradigms in distributed application development

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    This paper aims at demonstrating the benefits and importance of interaction systems design in the development of distributed applications. We position interaction systems design with respect to two paradigms that have influenced the design of distributed applications: the middleware-centred and the protocol-centred paradigm. We argue that interaction systems that support application-level interactions should be explicitly designed, using the externally observable behaviour of the interaction system as a starting point in interaction systems design. This practice has two main benefits: to promote a systematic design method, in which the correctness of the design of an interaction system can be assessed against its service specification; and, to shield the design of application parts that use the interaction system from choices in the design of the supporting interaction system

    On the Notion of Abstract Platform in MDA Development

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    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

    Optimality conditions for the calculus of variations with higher-order delta derivatives

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    We prove the Euler-Lagrange delta-differential equations for problems of the calculus of variations on arbitrary time scales with delta-integral functionals depending on higher-order delta derivatives.Comment: Submitted 26/Jul/2009; Revised 04/Aug/2010; Accepted 09/Aug/2010; for publication in "Applied Mathematics Letters
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