http://hdl.handle.net/10500/128 2013-05-18T06:30:04Z 2013-05-18T06:30:04Z Mtsweni, Jabu Saul http://hdl.handle.net/10500/9380 2013-05-09T12:22:23Z 2013-05-09T00:00:00Z

iSemServ: a framework for engineering intelligent semantic services Mtsweni, Jabu Saul The need for modern enterprises and Web users to simply and rapidly develop and deliver platform-independent services to be accessed over the Web by the global community is growing. This is self-evident, when one considers the omnipresence of electronic services (e-services) on the Web. Accordingly, the Service-Oriented Architecture (SOA) is commonly considered as one of the de facto standards for the provisioning of heterogeneous business functionalities on the Web. As the basis for SOA, Web Services (WS) are commonly preferred, particularly because of their ability to facilitate the integration of heterogeneous systems. However, WS only focus on syntactic descriptions when describing the functional and behavioural aspects of services. This makes it a challenge for services to be automatically discovered, selected, composed, invoked, and executed – without any human intervention. Consequently, Semantic Web Services (SWS) are emerging to deal with such a challenge. SWS represent the convergence of Semantic Web (SW) and WS concepts, in order to enable Web services that can be automatically processed and understood by machines operating with limited or no user intervention. At present, research efforts within the SWS domain are mainly concentrated on semantic services automation aspects, such as discovery, matching, selection, composition, invocation, and execution. Moreover, extensive research has been conducted on the conceptual models and formal languages used in constructing semantic services. However, in terms of the engineering of semantic services, a number of challenges are still prevalent, as demonstrated by the lack of development and use of semantic services in real-world settings. The lack of development and use could be attributed to a number of challenges, such as complex semantic services enabling technologies, leading to a steep learning curve for service developers; lack of unified service platforms for guiding and supporting simple and rapid engineering of semantic services, and the limited integration of semantic technologies with mature service-oriented technologies. vi In addition, a combination of isolated software tools is normally used to engineer semantic services. This could, however, lead to undesirable consequences, such as prolonged service development times, high service development costs, lack of services re-use, and the lack of semantics interoperability, reliability, and re-usability. Furthermore, available software platforms do not support the creation of semantic services that are intelligent beyond the application of semantic descriptions, as envisaged for the next generation of services, where the connection of knowledge is of core importance. In addressing some of the challenges highlighted, this research study adopted a qualitative research approach with the main focus on conceptual modelling. The main contribution of this study is thus a framework called iSemServ to simplify and accelerate the process of engineering intelligent semantic services. The framework has been modelled and developed, based on the principles of simplicity, rapidity, and intelligence. The key contributions of the proposed framework are: (1) An end-to-end and unified approach of engineering intelligent semantic services, thereby enabling service engineers to use one platform to realize all the modules comprising such services; (2) proposal of a model-driven approach that enables the average and expert service engineers to focus on developing intelligent semantic services in a structured, extensible, and platform-independent manner. Thereby increasing developers’ productivity and minimizing development and maintenance costs; (3) complexity hiding through the exploitation of template and rule-based automatic code generators, supporting different service architectural styles and semantic models; and (4) intelligence wrapping of services at message and knowledge levels, for the purposes of automatically processing semantic service requests, responses and reasoning over domain ontologies and semantic descriptions by keeping user intervention at a minimum. The framework was designed by following a model-driven approach and implemented using the Eclipse platform. It was evaluated using practical use case scenarios, comparative analysis, and performance and scalability experiments. In conclusion, the iSemServ framework is considered appropriate for dealing with the complexities and restrictions involved in engineering intelligent semantic services, especially because the amount of time required to generate intelligent semantic vii services using the proposed framework is smaller compared with the time that the service engineer would need to manually generate all the different artefacts comprising an intelligent semantic service. Keywords: Intelligent semantic services, Web services, Ontologies, Intelligent agents, Service engineering, Model-driven techniques, iSemServ framework.

2013-05-09T00:00:00Z Mukeru, Bahati http://hdl.handle.net/10500/8909 2013-04-13T22:00:44Z 2012-03-01T00:00:00Z

Bound states for A-body nuclear systems Mukeru, Bahati In this work we calculate the binding energies and root-mean-square radii for A−body nuclear bound state systems, where A ≥ 3. To study three−body systems, we employ the three−dimensional differential Faddeev equations with nucleon-nucleon semi-realistic potentials. The equations are solved numerically. For this purpose, the equations are transformed into an eigenvalue equation via the orthogonal collocation procedure using triquintic Hermite splines. The resulting eigenvalue equation is solved using the Restarted Arnoldi Algorithm. Ground state binding energies of the 3H nucleus are determined. For A > 3, the Potential Harmonic Expansion Method is employed. Using this method, the Schr¨odinger equation is transformed into coupled Faddeev-like equations. The Faddeevlike amplitudes are expanded on the potential harmonic basis. To transform the resulting coupled differential equations into an eigenvalue equation, we employ again the orthogonal collocation procedure followed by the Gauss-Jacobi quadrature. The corresponding eigenvalue equation is solved using the Renormalized Numerov Method to obtain ground state binding energies and root-mean-square radii of closed shell nuclei 4He, 8Be, 12C, 16O and 40Ca.

2012-03-01T00:00:00Z Nkuna, John Solly http://hdl.handle.net/10500/8828 2013-04-18T06:26:07Z 2012-06-01T00:00:00Z

Structure of hypernuclei studied with the integrodifferential equations approach Nkuna, John Solly A two-dimensional integrodi erential equation resulting from the use of potential harmonics expansion in the many-body Schr odinger equation is used to study ground-state properties of selected few-body nuclear systems. The equation takes into account twobody correlations in the system and is applicable to few- and many-body systems. The formulation of the equation involves the use of the Jacobi coordinates to de ne relevant global coordinates as well as the elimination of center-of-mass dependence. The form of the equation does not depend on the size of the system. Therefore, only the interaction potential is required as input. Di erent nucleon-nucleon potentials and hyperon-nucleon potentials are employed to construct the Hamiltonian of the systems. The results obtained are in good agreement with those obtained using other methods.

2012-06-01T00:00:00Z van der Merwe, Thomas http://hdl.handle.net/10500/8626 2013-02-16T22:00:31Z 2012-11-12T00:00:00Z

Applying the Community of Inquiry framework: a novel tool for systematic and economic coding and analysis of forum discourse in situ and in context van der Merwe, Thomas The online discussion forum (ODF) is one of the most widely used e-learning tools in open distance learning (ODL) environments. A popular line of research focuses on producing instruments that can be used to assess the level and amount of learning that takes place via transcript analysis of ODF-discourse. Of current interest is the influential community of inquiry (CoI) theoretical framework, first described by Garrison, Anderson and Archer in 2000. With validation of an ever-evolving framework a constant research focus, the CoI literature provides little insight into educator-level experiences when applying the framework. This paper describes and documents the author's approach and experience in using the framework to assess the status of the CoI in an ODF-driven course. In particular, it describes the motivation for, design, application and analysis results achieved with a novel tool that allows systematic and economical coding and analysis of ODF discourse in situ and in context.

2012-11-12T00:00:00Z