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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Role oriented adaptive design

Colman, Alan Wesley, n/a January 2006 (has links)
Software systems are becoming inexorably more open, distributed, pervasive, mobile and connected. This thesis addresses the problem of how to build adaptive software systems. These systems need to reliably achieve system-level goals in volatile environments, where the system itself may be built from components of uncertain behaviour, and where the requirements for the software system may be changing. This thesis adopts the systemtheoretic concept of ontogenic adaptation from biology, and applies it to software architecture. Ontogenic adaptation is the ability of an individual system to maintain its organisational integrity by reconfiguring and regulating itself. A number of approaches to adaptive software architecture have been recently proposed that, to varying degrees, enable limited adaptive behaviour and reconfiguration, but none possess all the properties needed for ontogenic adaptation. We introduce a meta-model and framework called Role Oriented Adaptive Design (ROAD) that is consistent with the concept of maintaining organisational integrity through ontogenic adaptation. The ROAD meta-model defines software applications as networks of functional roles which are executed by players (objects, components, services, agents, people, or rolecomposites). These flexible organisational structures are adaptive because the relationships (contracts) between roles, and the bindings between roles and players, can be regulated and reconfigured at run-time. Such flexible organisational role-structures are encapsulated into composites each with its own organiser. Because self-managed composites are themselves role-players, these composites can be distributed and recursively composed. The organisers of the composites form a management system over which requirements and performance data pass. Rather than being monolithic constructions, ROAD software applications are dynamic, self-managed compositions of loosely-coupled, and potentially, distributed entities. The concepts in the ROAD meta-model have been implemented in a programming framework which can be extended by the application programmer to create adaptive applications. Central to this framework are dynamic contracts. These contracts define the role structure, control interactions between the role instances, and measure the performance of those interactions. Adaptivity is achieved by monitoring and manipulating these contracts, along with the role-player bindings. Contracts have been implemented using the mechanism of �association aspects�. The applicability of the ROAD framework to the domain of Service-Oriented Computing is demonstrated. The framework is further evaluated in terms of its ability to express the concept of ontogenic adaptation and also in terms of the overhead its runtime infrastructure imposes on interactions.
2

Analysis of cloud testbeds using opensource solutions

Mohammed, Bashir, Kiran, Mariam January 2015 (has links)
Cloud computing is increasingly attracting large attention both in academic research and in industrial initiatives. However, despite the popularity, there is a lack of research on the suitability of software tools and parameters for creating and deploying Cloud test beds. Virtualization and how to set up virtual environments can be done through software tools, which are available as open source, but there still needs to be work in terms of which tools to use and how to monitor parameters with the suitability of hardware resources available. This paper discusses the concepts of virtualization, as a practical view point, presenting an in-depth critical analysis of open source cloud implementation tools such as CloudStack, Eucalyptus, Nimbus, OpenStack, OpenNebula, OpenIoT, to name a few. This paper analyzes the various toolkits, parameters of these tools, and their usability for researchers looking to deploy their own Cloud test beds. The paper also extends further in developing an experimental case study of using OpenStack to construct and deploy a test bed using current resources available in the labs at the University of Bradford. This paper contributes to the theme of software setups and open source issues for developing Cloud test bed for deploying and constructing private Cloud test bed.
3

Driving and inhibiting factors in the adoption of open source software in organisations

Greenley, Neil January 2015 (has links)
The aim of this research is to investigate the extent to which Open Source Software (OSS) adoption behaviour can empirically be shown to be governed by a set of self-reported (driving and inhibiting) salient beliefs of key informants in a sample of organisations. Traditional IS adoption/usage theory, methodology and practice are drawn on. These are then augmented with theoretical constructs derived from IT governance and organisational diagnostics to propose an artefact that aids the understanding of organisational OSS adoption behaviour, stimulates debate and aids operational management interventions. For this research, a combination of quantitative methods (via Fisher's Exact Test) and complimentary qualitative method (via Content Analysis) were used using self-selection sampling techniques. In addition, a combination of data and methods were used to establish a set of mixed-methods results (or meta-inferences). From a dataset of 32 completed questionnaires in the pilot study, and 45 in the main study, a relatively parsimonious set of statistically significant driving and inhibiting factors were successfully established (ranging from 95% to 99.5% confidence levels) for a variety for organisational OSS adoption behaviours (i.e. by year, by software category and by stage of adoption). In addition, in terms of mixed-methods, combined quantitative and qualitative data yielded a number of factors limited to a relatively small number of organisational OSS adoption behaviour. The findings of this research are that a relatively small set of driving and inhibiting salient beliefs (e.g. Security, Perpetuity, Unsustainable Business Model, Second Best Perception, Colleagues in IT Dept., Ease of Implementation and Organisation is an Active User) have proven very accurate in predicting certain organisational OSS adoption behaviour (e.g. self-reported Intention to Adopt OSS in 2014) via Binomial Logistic Regression Analysis.

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