3,946 research outputs found

    A model-driven approach to non-functional analysis of software architectures

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    Generating a contract checker for an SLA language

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    SLAng is a language for expressing Service LevelAgreements (SLAs) under development as part of the Europeanproject TAPAS. It is defined using a meta-model, an instance ofthe Meta-Object Facility (MOF) model, in which the relationshipbetween the syntax of the language and its domain of applicationis explicitly represented, and the violation semantics ofthe language defined using Object Constraint Language (OCL)constraints. The concrete syntax of the language is the XMLMeta-data Interchange (XMI) mapping of the syntactic part ofthe meta-model. In this paper we describe how the Java MetadataInterface (JMI) mapping can be applied to the meta-modelof the language to generate interfaces and classes to create andquery SLAs and relevant service monitoring data in memory;and how an OCL interpreter can be applied to check violationconstraints over this data, resulting in the implementation of acontract checker that is highly likely to respect the semantics ofthe language

    Precise service level agreements

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    SLAng is an XML language for defining service level agreements, the part of a contract between the client and provider of an Internet service that describes the quality attributes that the service is required to possess. We define the semantics of SLAng precisely by modelling the syntax of the language in UML, then embedding the language model in an environmental model that describes the structure and behaviour of services. The presence of SLAng elements imposes behavioural constraints on service elements, and the precise definition of these constraints using OCL constitutes the semantic description of the language. We use the semantics to define a notion of SLA compatibility, and an extension to UML that enables the modelling of service situations as a precursor to analysis, implementation and provisioning activities

    Modelling electronic service systems using UML

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    This paper presents a profile for modelling systems of electronic services using UML. Electronic services encapsulate business services, an organisational unit focused on delivering benefit to a consumer, to enhance communication, coordination and information management. Our profile is based on a formal, workflow-oriented description of electronic services that is abstracted from particular implementation technologies. Resulting models provide the basis for a formal analysis to verify behavioural properties of services. The models can also relate services to management components, including workflow managers and Electronic Service Management Systems (ESMSs), a novel concept drawn from experience of HP Service Composer and DySCo (Dynamic Service Composer), providing the starting point for integration and implementation tasks. Their UML basis and platform-independent nature is consistent with a Model-Driven Architecture (MDA) development strategy, appropriate to the challenge of developing electronic service systems using heterogeneous technology, and incorporating legacy systems

    The circular economy: An interdisciplinary exploration of the concept and application in a global context

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    There have long been calls from industry for guidance in implementing strategies for sustainable development. The Circular Economy represents the most recent attempt to conceptualize the integration of economic activity and environmental wellbeing in a sustainable way. This set of ideas has been adopted by China as the basis of their economic development (included in both the 11th and the 12th ā€˜Five Year Planā€™), escalating the concept in minds of western policymakers and NGOs. This paper traces the conceptualisations and origins of the Circular Economy, tracing its meanings, and exploring its antecedents in economics and ecology, and discusses how the Circular Economy has been operationalized in business and policy. The paper finds that while the Circular Economy places emphasis on the redesign of processes and cycling of materials, which may contribute to more sustainable business models, it also encapsulates tensions and limitations. These include an absence of the social dimension inherent in sustainable development that limits its ethical dimensions, and some unintended consequences. This leads us to propose a revised definition of the Circular Economy as ā€œan economic model wherein planning, resourcing, procurement, production and reprocessing are designed and managed, as both process and output, to maximize ecosystem functioning and human well-beingā€

    SLAng: A language for defining service level agreements

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    Application or web services are increasingly being used across organisational boundaries. Moreover, new services are being introduced at the network and storage level. Languages to specify interfaces for such services have been researched and transferred into industrial practice. We investigate end-to-end quality of service (QoS) and highlight that QoS provision has multiple facets and requires complex agreements between network services, storage services and middleware services. We introduce SLAng, a language for defining Service Level Agreements (SLAs) that accommodates these needs. We illustrate how SLAng is used to specify QoS in a case study that uses a web services specification to support the processing of images across multiple domains and we evaluate our language based on it

    The Nova Scotia Law Reform Advisory Commission: An Early Appraisal

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    The Nova Scotia Law Reform Advisory Commission has now been in existence for two and a half years, having been established by the Law Reform Act 19691 and constituted by an Order of the Governor in Council on January 25, 1972. As the members of the Commission are appointed for a period of two years, the term of appointment of the first members of the Commission expired on January 25 this year, but new members were not in fact appointed until June 25 this year. From February to June, the Commission was more or less in limbo. In view of the recent appointment of the new members and the commencement of a new era in the Commission\u27s activities, it is the purpose of these notes first to review the progress of the Commission in its first two years and second, to suggest ways in which the Commission might be improved or operate more effectively in future. The notes are divided into parts, each dealing with one aspect of the Commission and its activities - its construction, its terms of reference, its powers and the fetters on its powers, its programme and plans for the future, its procedure for implementing its plans, its finances, its relationship with the different branches of the legal profession and its general function in the community. The intention is not be be unduly critical of the Commission at this early stage, but rather to offer some constructive suggestions for its future development

    Teaching with difference : barriers and enablers for teachers with impairments in their professional roles

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    Amidst the current groundswell of inclusive practices adopted in learning institutions, there would appear to be a paucity of research regarding the barriers and enablers experienced by teachers with impairments in Australian education systems (Burke, 2016; Pritchard, 2010; Sheridan & Kotevski, 2014). This thesis presents an examination of national and international literature where an imprecise range of issues for teachers with impairments is identified. The social model of disability has been adopted as the overarching theoretical perspective for this study. The conceptualisation of teaching with impairment, rather than about impairment, embodies the notion of teachers with impairments as being culturally relevant educators (Pritchard, 2010). Narrative inquiry, in conjunction with Clandinin and Connellyā€™s (2000) three-dimensional space approach as a thematical analysis methodology, has been employed and supports the investigation of ten teachers with impairments working in professional education roles within Australia. Narrative interviews were conducted with each of the ten participants with the aim of identifying barriers and enablers within the lived experiences of teachers with impairments. This study identified a silence in relation to teachers with impairments, and to address this silence has amplified the voices of teachers with impairments. Five primary themes emerged from the data to provide insights into barriers and enablers experienced by teachers with impairments. These themes are: Thinking about becoming a teacher; The limiting attitudes of others; Connecting with students and parents; Notions of teaching spaces; and I get by with a little help from my friends. This study found that teachers with impairments do experience adverse attitudes and biases in Australian teaching institutions despite there being laws that have been specifically designed to prevent disability discrimination. Bias, experienced as discrimination towards teachers with impairments, extends to career promotion and workplace advancement opportunities. Conversely, the study also found that respectful conversations about impairment which took place both inside and outside teaching places, highlighted how having open conversations about reasonable adjustments can lead to actions that become enablers for teachers with impairments. This study commences the important work of giving voice to teachers with impairments and creates a space to challenge dominant perspectives. The thesis concludes that more needs to be done to challenge the constructed normative attitudes that are responsible for setting teachers with impairments apart and resulting in them being mostly undetected within the teacher population; Doctor of Philosoph
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