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Thesis (M.S.)--Rochester Institute of Technology, 1983. / Typescript. Includes bibliographical references (leaves 74-78).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

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Typescript, etc. / Digitized by Kansas Correctional Industries

Research on software architectures has been active since the early nineties, leading to a number of different architecture description languages (ADL). Given their importance in facilitating the communication of crucial system properties to different stakeholders and their analysis early on in the development of a system this is understandable. However, practitioners rarely use ADLs, and, instead, they insist on using the Unified Modelling Language (UML) for specifying software architectures. I attribute this to three main issues that have not been addressed altogether by the existing ADLs. Firstly, in their attempt to support formal analysis, current ADLs employ formal notations (i.e., mostly process algebras) that are rarely used among practitioners. Secondly, many ADLs focus on components in specifying software architectures, neglecting the first-class specification of complex interaction protocols as connectors. They view connectors as simple interaction links that merely identify the communicating components and their basic communication style (e.g., procedure call). So, complex interaction protocols are specified as part of components, which however reduce the re-usability of both. Lastly, there are also some ADLs that do support complex connectors. However, these include a centralised glue element in their connector structure that imposes a global ordering of actions on the interacting components. Such global constraints are not always realisable in a decentralised manner by the components that participate in these protocols. In this PhD thesis, I introduce a new architecture description language called XCD that supports the formal specification of software architectures without employing a complex formal notation and offers first-class connectors for maximising the re-use of components and protocols. Furthermore, by omitting any units for specifying global constraints (i.e., glue), the architecture specifications in XCD are guaranteed to be realisable in a decentralised manner. I show in the thesis how XCD extends Design-by-Contract (DbC) for specifying (i) protocol-independent components and (ii) complex connectors, which can impose only local constraints to guarantee their realisability. Use of DbC will hopefully make it easier for practitioners to use the language, compared to languages using process algebras. I also show the precise translation of XCD into SPIN’s formal ProMeLa language for formally verifying software architectures that (i) services offered by components are always used correctly, (ii) the component behaviours are always complete, (iii)there are no race-conditions, (iv) there is no deadlock, and (v) for components having event communications, there is no overflow of event buffers. Finally, I evaluate XCD via five well-known case studies and illustrate XCD’s enhanced modularity, expressive DbC-based notation, and guaranteed realisability for architecture specifications.

A lot of contemporary cloud computing platforms offer Infrastructure-as-a-Service provisioning model, which offers to deliver basic virtualized computing resources like storage, hardware, and networking as on-demand and dynamic services. However, a single cloud service provider does not have limitless resources to offer to its users, and increasingly users are demanding the features of extensibility and inter-operability with other cloud service providers. This has increased the complexity of the cloud ecosystem and resulted in the emergence of the concept of an Inter-Cloud environment where a cloud computing platform can use the infrastructure resources of other cloud computing platforms to offer a greater value and flexibility to its users. However, there are no common models or standards in existence that allows the users of the cloud service providers to provision even some basic services across multiple cloud service providers seamlessly, although admittedly it is not due to any inherent incompatibility or proprietary nature of the foundation technologies on which these cloud computing platforms are built. Therefore, there is a justified need of investigating models and frameworks which allow the users of the cloud computing technologies to benefit from the added values of the emerging Inter-Cloud environment. In this dissertation, we present a novel security model and protocols that aims to cover one of the most important gaps in a subsection of this field, that is, the problem domain of provisioning secure communication within the context of a multi-provider Inter-Cloud environment. Our model offers a secure communication framework that enables a user of multiple cloud service providers to provision a dynamic application-level secure virtual private network on top of the participating cloud service providers. We accomplish this by taking leverage of the scalability, robustness, and flexibility of peer-to-peer overlays and distributed hash tables, in addition to novel usage of applied cryptography techniques to design secure and efficient admission control and resource discovery protocols. The peer-to-peer approach helps us in eliminating the problems of manual configurations, key management, and peer churn that are encountered when setting up the secure communication channels dynamically, whereas the secure admission control and secure resource discovery protocols plug the security gaps that are commonly found in the peer-to-peer overlays. In addition to the design and architecture of our research contributions, we also present the details of a prototype implementation containing all of the elements of our research, as well as showcase our experimental results detailing the performance, scalability, and overheads of our approach, that have been carried out on actual (as opposed to simulated) multiple commercial and non-commercial cloud computing platforms. These results demonstrate that our architecture incurs minimal latency and throughput overheads for the Inter-Cloud VPN connections among the virtual machines of a service deployed on multiple cloud platforms, which are 5% and 10% respectively. Our results also show that our admission control scheme is approximately 82% more efficient and our secure resource discovery scheme is about 72% more efficient than a standard PKI-based (Public Key Infrastructure) scheme.

The visualisation of large volumes of data can provide rich and meaningful representations that enable users to gain insights quickly and efficiently. Household energy consumer characteristics are explored in this thesis using innovative interactive visualisation techniques. Initial research with energy analysts, from a major UK utility company, investigates visual possibilities and opportunities for future (smart home) energy analytics and explicitly uses creativity techniques for information visualisation requirements gathering. The results, along with exploratory visual analysis combining geodemographic groups and energy consumption, identifes a need for profiling consumers by typical traits. While energy consumption has been a popular topic of research in recent years, there is still limited understanding of the relationship between energy consumption and measurable characteristics of the general population. An investigation of the process of creating an energy-based geodemographic classification led to the proposal and design of a new theoretical framework for visually comparing multivariate data across scale and geography; a necessary step when selecting reliable variables for running clustering algorithms, such as during the geodemographic classification creation process. The framework for including geography and scale in multivariate comparison forms the major contribution of this thesis. This framework is demonstrated and justified through the building of an interactive visualisation prototype, using input variables deemed relevant for consideration for energy-based geodemographic classification. Important transitions in the framework are highlighted in the proposed design, which uses both statistical and spatial representations. The utility of the framework is validated in the context of energy-based geodemographic variable selection where the multivariate geography of the UK is explored. The sensitivities of varying scale and geography { through varying resolution, extent and the calculation of locally weighted summary statistics { are investigated in context and are shown to be important elements to consider during the variable selection process. The broader applicability of the framework is demonstrated through two further scenarios where multivariate visualisation across scale and geography is shown to be important. The research provides a framework and viable solutions through which geographical visual parameter space analysis (gvPSA) can be undertaken. It uses a design science approach that results in a series of artifacts that open up new visualisation possibilities. This project covers a wide topic where the breadth of research options is extensive and many possibilities for continued research are identified.

A natural extension of play for creative thinking can innovatively drive technology-led changes to the facilitation of creative problem solving, and generate a new genre in serious gaming. Whilst the use of serious games has grown considerably in recent years, support for players to think creatively is often implicit in the game, and does not exploit the wide range of creativity techniques and software tools available. The work reported in this thesis is the first to explicitly integrate creativity support into serious games. The results show that creative serious games can systematically support acquisition of creativity skills, generation of creative learning outcomes, and induction of motivational and learning benefits amongst the players. Therefore, this thesis introduces the concept of explicit creativity support in serious games, with a focus on games for motivated learning in adult professional setting, and reports formative and summative evaluations of new prototype games for this setting, in order to instantiate, refine and validate the concept. The creative learning objective of the prototype games was to train carers in creativity techniques to deliver more person-centred care to people with dementia. The findings are delivered in the form of a new framework, which proposes recommendations for the design and understanding of creative serious games. Four formative evaluations of three prototypes of creative serious games with carers provided results that led to refinements of the framework and the design of more usable and effective games. A subsequent summative evaluation partially validated the framework, delivering both a framework and prototype creative serious game that demonstrated the potential to improve person-centred dementia care training. The thesis provides a proof-of-concept of the value of creative serious games, and shows the potential for the framework to be applied and have impact on other application domains.