Density-based clustering is one of the well-known algorithms focusing on grouping samples according to their densities. In the existing density-based clustering algorithms, samples are clustered according to the total number of points within the radius of the defined dense region. This method of determining density, however, provides little knowledge about the similarities among points. Additionally, they are not flexible enough to deal with dynamic data that changes over time. The current study addresses these challenges by proposing a new approach that incorporates new measures to evaluate the attributes similarities while clustering incoming samples rather than considering only the total number of points within a radius. The new approach is developed based on the notion of Gravity where incoming samples are clustered according to the force of their neighbouring samples. The Mass (density) of a cluster is measured using various approaches including the number of neighbouring samples and Silhouette measure. Then, the neighbouring sample with the highest force is the one that pulls in the new incoming sample to be part of that cluster. Taking into account the attribute similarities of points provides more information by accurately defining the dense regions around the incoming samples. Also, it determines the best neighbourhood to which the new sample belongs. In addition, the proposed algorithm introduces a new approach to utilize the memory efficiently. It forms clusters with different shapes over time when dealing with dynamic data. This approach, called Aging, enables the proposed algorithm to utilize the memory efficiently by removing points that are aged if they do not participate in clustering incoming samples, and consequently, changing the shapes of the clusters incrementally. Four experiments are conducted in this study to evaluate the performance of the proposed algorithm. The performance and effectiveness of the proposed algorithm are validated on a synthetic dataset (to visualize the changes of the clusters’ shapes over time), as well as real datasets. The experimental results confirm that the proposed algorithm is improved in terms of the performance measures including Dunn Index and SD Index. The experimental results also demonstrate that the proposed algorithm utilizes less memory, with the ability to form clusters with arbitrary shapes that are changeable over time.

Mass production of translationally optimized bacteriophages (hereafter referred to as phages) is the need of the hour in the application of phages to therapy. Understanding translational efficiency of phages is the major preliminary step for mass producing efficient phages. The objective of this thesis is to understand factors affecting translational efficiency of phages. In chapter two, we hypothesized that weak translation initiation efficiency is responsible for weak codon concordance of Escherichia coli lambdoid phages with that of their hosts. We measured the strength of translation initiation using two indices namely minimum folding energy (MFE) and proportion of Shine-Dalgarno sequence (PSD). Empirical results substantiate our hypothesis suggesting lack of strong selection for improving codon adaptation in these phages is due to their weak translation initiation. In chapter three, we measured codon usage concordance between GC-rich and GC-poor Aeromonas phages with their GC-rich host Aeromonas salmonicida. We found low codon usage concordance in the GC-poor Aeromonas phages. We were interested in testing for the role of tRNAs in the GC-poor phages. We observed that the GC-poor phages carry tRNAs for codons that are overused by the phages and underused by the host. These findings suggest that the GC-poor Aeromonas phages carry their own tRNAs for compensating for the compositional difference between their genomes and that of their host. Previously several studies have reported observed avoidance of stable secondary structures in start site of mRNA in a wide range of species. We probed the genomes of 422 phage species and measured their secondary structure stability using MFE. We observed strong patterns of secondary structure avoidance (less negative MFE values) in the translation initiation region (TIR) and translation termination region (TTR) of all analyzed phages. These findings imply selection is operating at these translationally important sites to control stable secondary structures in order to maintain efficient translation.

There is a growing popularity among musicians to turn to somatic approaches such as the Alexander Technique, Body Mapping and Feldenkrais Method to improve posture and movement at the instrument and to produce better tone quality. There is little scientific and objective data to support the changes that are apparently seen and heard after such training. This study examines if a single somatic session has an immediate, perceivable effect on pianists’ body usage and musical quality. In the first mode of evaluation, judges rated specific aspects of body usage and musical quality. In the second mode of evaluation, judges were asked to identify post-somatic performances. Results indicated that there are perceivable changes in body usage and musical quality although those differences are not as apparent or easily detectable as is often believed. The findings also suggest that it is easier to identify post-somatic performances through body usage than musical quality.

General characteristic of web mining including methodology and procedures incorporated into this term. Relation to other areas (data mining, artificial intelligence, statistics, databases, internet technologies, management etc.) Web usage mining - data sources, data pre-processing, characterization of analytical methods and tools, interpretation of outputs (results), and possible areas of usage including examples. Suggestion of solution method, realization and a concrete example's outputs interpretation while using above mentioned methods of web usage mining.

Currently, Business Intelligence has a very solid position in the enterprise information systems' market. However, there is no unified approach to the evaluation of effects of these solutions in the enterprise. It is a common practice that the transmission of the accepted solution automatically means successful completion of the development project, causing a gradual decrease in the supplier's interest of the users' satisfaction with this solution. This thesis deals with the problem of evaluating the success of custom Business Intelligence solutions. The main objective of this work is a new perspective on the issue of users' satisfaction and create a generally applicable concept for its evaluation. This objective will be achieved on the basis of a comprehensive theoretical analysis of effects of these solutions with the reasons why the work focuses on the analysis of users. It presents a total of two methods for evaluating the users' satisfaction of reporting solutions from the users. In order to demonstrate the viability of this concept, the two methods will be applied in practical part to a specific BI solution, including the demonstration of achieved results and assessing the suitability of both methods. This section is based on the experience of the real project.

La mise en place de la gratuité de l'école primaire, il y a 8 ans a offert à la majorité des enfants kenyans, notamment les plus défavorisés (les filles dans certaines régions, les enfants issus de familles pauvres ou rurales) qui n'y avaient pas accès jusqu'alors, l'opportunité de s ‘inscrire à l'école. L'objectif du gouvernement kenyan est d'améliorer la qualité de l'enseignement reçu dans l'éducation publique. De nouvelles approches d'enseignement et d'apprentissage sont nécessaires pour assurer le progrès pédagogique et à travers lui améliorer la qualité de l'enseignement. Dans une économie où 40 % de la main-d'œuvre qualifiée est au chômage, l'accent doit être mis sur une formation de la population afin de répondre au mieux aux demandes du marché du travail. L'une des stratégies pour améliorer la qualité de l'éducation est l'intégration des TIC, comme moyen de généraliser l'éducation et de garantir un accès équivalent aux élèves de toutes les régions du Kenya. Ayant entériné l'introduction des ordinateurs dans les classes depuis plus de dix ans, le gouvernement est en quête de méthodes d'enseignement qui accorderaient une place plus importante à l'informatique dans toutes les matières enseignées et ne se limiteraient pas simplement à un projet d'alphabétisation informatique. Cette thèse essaie d'identifier et d'analyser diverses utilisations de logiciels éducatifs présents à des élèves kenyans du secondaire. Nous nous sommes inspirés des approches proposées par Papert et Cuban, dont les perspectives sont de rendre l'apprentissage ludique tout en étant efficace, grâce à l'utilisation de logiciels éducatifs lors des séances d'enseignement. / The expansion of access to primary éducation eight years ago has led to majority of children in Kenya notably the less priviledged like girls and those from poor or rural households to be enrolled in school for the first time. Despite the govenment's aim to increase resources for public éducation, primary and secondary schools are over stretched in terms of capacity. New approches to teaching and learning are necessary in order to ensure quality and progress in the pedagogical aréna. In an economy where 40% of its qualified manpower is unemployed, focus must be turned to effective training of its population to meet the job market's demands. One of the stratégies of improving quality of education is the integration of technologies such as ICT, as a way of globalizing the éducation process and ensuring equity in access. Having accepted the introduction of computers into the classroom more than ten years ago, the government is on a quest to find a more integrated approach of computers in specific subject areas rather than simply computer literacy. This thesis tries to identify and analyse different uses of educational software in the kenyan classroom at secondary school level. Leaning on approaches suggested by Papert and Cuban, on the prospects of making learning fun and effective through the use of software in the school environment.

In the past decade, there has been a transformation in how businesses are done, many business chose to adopt digitization and others were forced to go with the flow. As a part of this digital revolution, social media has reserved a big share of this transformation in how companies do their marketing and communicate their product and brand image to their customers. Social media in a business to customer context has been very common since the birth of social media, companies had realized its benefit, and however, it is still in an early phase in a business to business context. Social media has become an effective marketing tool for B2B companies, yet, there are still drawbacks when companies fail to know how to use such platforms to their benefit and merely have a shy presence or do not have a well-defined strategy to the use of social media in the most effective way. A vital step when incorporating social media in marketing is to create a clear goals and metrics. However, it has been seen that many companies lack the expertise, resources and the know-how, to implement a social media marketing strategy. Therefore, the purpose of this study is to explore the practices of B2B companies when they use social media without a clearly defined social media marketing strategy, what they do when they use social media.

<p>NR 20140805</p>

The building sector is a major contributor to theenvironmental loads generated by the society. The recognitionof this fact by the sector and a general strive toward asustainable society have lead to afocus on different toolsthat can be used to enhance the environmental performance ofthe sector and the society. Life Cycle Assessment (LCA) is oneof these tools. The LCA methodology was initially developed forassessments of short-lived consumer products. The increasinginterest in using the LCA methodology in the context of thebuilding sector has initiated a development of the methodologyto be able to consider the specific characteristics andconsiderations of the building sector. These are specific forthe building sector, but not always unique. Examples ofcharacteristics and considerations are: that each building isunique, the functional output is not always a physical productbut rather a service, the long service lives of buildings.These have implications on several elements in the LCAmethodology. The influenced elements that are dealt with inthis thesis are in particular the modeling of the system, thefunctional unit, boundary setting, life cycle scenarios,scenarios and inventory of the usage phase and allocationprocedures. Buildings and constructions are commonly not static systems.The systems are rather dynamic in the sense that the systemwill provide different services based on the same physicalstructure during its service life. To be able to model thedynamic system sequential life cycle thinking is introduced anda list of topics is derived. The list of topics is a structuredpresentation of issues that are of interest in the pursuit of aflexible LCA methodology. The goal is to find out if amethodological approach is suitable for modeling dynamicsystems with a functional unit that is based on the providedservice rather than the physical building. Boundary setting, life cycle scenarios, allocationprocedures, predicted service life and the modelling of theusage phase are all elements of the LCA methodology that havean potential to influence the result of an LCA in a significantway. The magnitude of the potential influence has beenmonitored based on the results of three case studies, whichhave been elaborated further to be able to estimate themagnitude of the potential influence. There is a multitude of available allocation procedurespresented and used in different contexts. The procedures aredeveloped based on different considerations and with differentintended applications. Two alternative allocation proceduresare presented in this thesis. The first is a proceduredeveloped with multi recyclable materials in mind and it isbased on the recyclability of materials and products. Thesecond procedure is quite recently developed and it is based ona combination of economic parameters and recyclability. The importance of the usage phase for buildings andconstructions has previously been recognised. The maincontributors to the environmental loads generated during theusage phase are energy use, maintenance and emissions fromproducts. It is, however, not very common to consider the usagephase in assessments conducted on materials and components,even though it is stipulated in e.g. ISO 14025 that the wholelife cycle should be considered. A proposal of a model toestimate the environmental loads is, therefore, presented. Keywords:Life cycle assessment, Building materials andcomponents, Buildings and constructions, Allocation, Resultvariation, Usage phase, Energy demand / <p>NR 20140805</p>

With the advent of agile programming, lightweight software processes are being favoured over the highly formalised approaches of the 80s and 90s, where the emphasis is on "people, not processes". Likewise, access control may benefit from a less prescriptive approach and an increasing reliance on users to behave ethically. These ideals correlate with optimistic access controls. However, such controls alone may not be adequate as they are retrospective rather proactive. Optimistic access controls may benefit from the stricter enforcement offered by usage control. The latter enables finer-grained control over the usage of digital objects than do traditional access control policies and models, as trust management concerns are also taken into consideration. This thesis investigates the possibility of enhancing optimistic access controls with usage control to ensure that users conduct themselves in a trustworthy manner. Since this kind of approach towards access control has limited applicability, the present study investigates contextualising this approach within a mixed-initiative access control framework. A mixed-initiative access control framework involves combining a minimum of two access control models where the request to information is mediated by a mixture of access policy enforcement agents. In order for this type of integration to be successful, a software development approach was considered that allows for the seamless augmentation of traditional access control with optimistic access control enhanced with usage control, namely the aspect-oriented approach. The aspect-oriented paradigm can facilitate the implementation of additional security features to legacy systems without modifying existing code. This study therefore evaluates the aspect-oriented approach in terms of implementing security concerns. It is evidently difficult to implement access control and in dynamic environments preconfigured access control policies may often change dramatically, depending on the context. In unpredicted circumstances, users who are denied access could often have prevented a catastrophe had they been allowed access. The costs of implementing and maintaining complex preconfigured access control policies sometimes far outweigh the benefits. Optimistic controls are retrospective and allow users to exceed their normal privileges. However, if a user accesses information unethically, the consequences could be disastrous. Therefore it is proposed that optimistic access control be enhanced with some form of usage control, which may prevent the user from engaging in risky behaviour. An initiative towards including security in the earlier phases of the software life cycle is gaining momentum, as it is much easier to design with security from the onset than to use the penetrate-and-patch approach. Unfortunately, incorporating security into software development takes time and developers tend to focus more on the features of the software application. The aspect-oriented paradigm can facilitate the implementation of additional security features in legacy systems without modifying existing code. The current study evaluates the aspect-oriented approach towards enhancing optimistic access control with usage control. The efficacy of the aspect-oriented paradigm has been well established within several areas of software security, as aspect-orientation facilitates the abstraction of these security-related tasks so as to reduce code complexity. / Thesis (PHD)--University of Pretoria, 2010. / Computer Science / unrestricted