Recent works show that, by incorporating queue length information, CSMA/CA multiple access protocols can achieve maximum throughput in general ad-hoc wireless networks. In all of these protocols, the aggressiveness with which a link attempts to grab the channel is governed solely by its own queue, and is independent of the queues of other interfering links. While this independence allows for minimal control signaling, it results in schedules that change very slowly. This causes starvation and delays - especially at moderate to high loads. In this work we add a very small amount of signaling - an occasional few bits between interfering links. These bits allow us a new functionality: switching - a link can now turn off its interfering links with a certain probability. The challenge is ensuring maximum throughput and lower delay via the use of this new functionality. We develop a new protocol - Switch-enabled Queue-based CSMA (SQ-CSMA) - that uses switching to achieve both of these objectives. This simple additional functionality, and our protocol to leverage it, can be “added on'' to every existing CSMA/CA protocol that uses queue lengths. Interestingly, we see that in every case it has a significant positive impact on delay, universally furthering the performance of existing protocols. / text

Using an already developed model for measuring the quality of online services, the authors of this thesis have developed and later on modified a theoretical model (instrument) for measuring the quality of online banking services in particular. Using quantitative research method including the design and distribution of a questionnaire, empirical data was collected on which statistical analysis has been performed. As a result of the conducted analysis, the initial theoretical model has been modified, so that the final version of the model (instrument) for measuring quality of online banking services includes four quality dimensions (Service Performance, Website Characteristics, Communication and Efficiency) with total of 17 items (questions). Furthermore, based on the modified theoretical model, customer satisfaction with different aspects of the online banking services has been evaluated. Based on the results of the Analysis of the Empirical Data, managerial recommendations are given. Suggestions for further research on quality of online banking services are also offered.

<p>Using an already developed model for measuring the quality of online services, the authors of this thesis have developed and later on modified a theoretical model (instrument) for measuring the quality of online banking services in particular. Using quantitative research method including the design and distribution of a questionnaire, empirical data was collected on which statistical analysis has been performed. As a result of the conducted analysis, the initial theoretical model has been modified, so that the final version of the model (instrument) for measuring quality of online banking services includes four quality dimensions (Service Performance, Website Characteristics, Communication and Efficiency) with total of 17 items (questions). Furthermore, based on the modified theoretical model, customer satisfaction with different aspects of the online banking services has been evaluated. Based on the results of the Analysis of the Empirical Data, managerial recommendations are given. Suggestions for further research on quality of online banking services are also offered.</p>

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The process of globalization over the past five decades has given impetus to drivensustainability and related thinking in business. It is also observed that there areunprecedented trends in corporate strategy towards sustainable thinking - the emergenceof sustainability as corporate strategy and the concern of business for ecology and society.This forces companies to rethink their standard business models and increase theirinterest in innovating products and services based on the challenges of global sustainabledevelopment. The pressure from external stakeholders, mainly non-governmentalorganizations (NGOs), as drivers of change may also contribute strongly to thisendeavour. This substantial change pressure clearly reflects companies’ recognition of themounting pressures for social responsibility and governance. The overall aim of this thesisis to describe and understand how social responsibility and value-creation of customers’influence the overall service quality of companies in developing a sustainable servicebusiness. The theoretical and conceptual frame of reference finds its stimulation from the researchin sustainable development – corporate social responsibility, service research and qualitymanagement. In this way it attempts to bridge the gap between business and socialresponsibility. Theoretically and conceptually, the thesis amalgamates sustainabilitythinking and the service logic. Here, value creation and co-creation of Service DominantLogic (S-D logic) approach expands to integrate the values based approach of CorporateSocial Responsibility (CSR) in management thinking and have created the prevailingbusiness practices and service quality (SQ) improvement. This thesis is a compilation offive different papers that follow an interpretative case study approach. The empiricalstudy developed from the cases of multinational companies, small and mediumenterprises, smallholders and NGOs. In this thesis, ‘Sustainable Service Dominant Logic’ (SSDL) was labelled to argue thatvalue-based co-creation of the S-D logic framework can be used to create values-basedservices for sustainable business by examining the link between CSR and S-D logic basedon value, values and service quality for sustainable business. This is this thesis’scontribution to the ongoing discussion of the paradigm shift in service research. Theframework is of the integration of CSR thinking into service business to create sustainablebusiness thinking. This signifies the new thinking of incorporating different managementsystems in creating the organizational change process, sustainability and finally SQimprovement. This counters the critique against S-D logic by expanding the societal andethical dimensions by using CSR, and showing real business cases. This depends on theintegration of different change pressures for value creation, whether related to economicand social resource integration. This involves the shift of the focus of managerial controlfrom a preoccupation with financial issues to a wider awareness of CSR thinking. Theseissues are also explored by demonstrating, based on cases, how the adoption of thisperspective can also enable the Base of the Pyramid (BoP) framework to become animportant aspect of value creation. Finally, the paradigm shift can be generalized to newthinking in S-D logic and the social responsibility of businesses as the major phenomenonof the changing and globalizing business environment; time for the CSR framework to permeate S-D logic.

This study was prompted by the recent increase in academic and public interest in neuromusical brain research, which provides information about how the brain processes music. It is the task of neural science to explain how the individual units of the brain are used to control behaviour, and how the functioning of these units is influenced by an individual's specific environment and relationships with other people. However, the concept of neuromusical research is relatively new to music education. In any learning experience, brain processing (of information) is not an end in itself. The skill of 'thinking' is dependent on the whole integrated mind/body system, with skills being a manifestation of conscious physical responses that demonstrate knowledge acquisition. Howard Gardner's 'Theory of Multiple Intelligences' lists the musical intelligence as one of eight autonomous intelligences: linguistic, logic-mathematical, spatial, bodily-kinesthetic, musical, intrapersonal, interpersonal, and environmental. All of these intelligences can be developed to a reasonably high level. This thesis uses David Elliott's praxial philosophy as a conceptual basis. Elliott's four meanings of music education: education in music, by music, for music, and by means of music, have been selected to determine the parameters for an 'inclusive' understanding of musical intelligence. Scientific research findings, brain based data, and behavioural results with educational implications have been used to define what is meant by the musical intelligence, and its role in whole brain learning. Whole brain learning (also referred to as 'accelerated' learning or 'super' learning) is examined in the framwork of IQ (intellectual quotient/intelligence), EQ (emotional intelligence), and SQ (spiritual intelligence). It is important to note that the brain imposes certain constraints on the learning ability of individuals, but that there are also numerous benefits to be derived from an awarenss of brain functions pertaining to education in general and music education in particular. These constraints and benefits are an important feature of whole brain learning, with the musical intelligence playing a vital role. / Dissertation (DMus)--University of Pretoria, 2003. / Music / unrestricted

By means of numerical simulations, the thesis aims at improvements in the understanding of light propagation in dielectric optical waveguides, with emphasis on nonreciprocal integrated magnetooptic devices. The results include: Proposal, implementation, and assessment of the WMM mode solver (Wave Matching Method) For waveguides with piecewise constant, rectangular permittivity profiles, the calculation of guided modes can be based on a local expansion into factorizing harmonic or exponential trial functions. A least squares expression for the mismatch in the continuity conditions at dielectric boundaries connects the fields on neighbouring regions. Minimization of this error allows to compute propagation constants and mode fields. The procedure has been implemented both for semivectorial and fully vectorial mode analysis. The piecewise defined trial fields are well suited to deal with field discontinuities or discontinuous derivatives. Numerical assessment shows excellent agreement with accepted previous results from other methods. The WMM turns out to be effective especially for structures described by only a few rectangles. It yields semianalytical mode field representations which are not restricted to a computational window. The fields are therefore perfectly suited for further processing, e.g. in the framework of various kinds of perturbation theory. Perturbational geometry tolerancing procedure Shifting the location of a dielectric boundary in the cross section of a waveguide with piecewise constant refractive index profile results in a permittivity perturbation in a layer along the discontinuity line. On the basis of these thin layer perturbations, perturbational expressions for the derivatives of the propagation constants with respect to geometry parameters are discussed. The approach provides direct access to wavelength dependences. Comparison with rigorously calculated data shows that the accuracy is sufficient to yield reasonable tolerance estimates for realistic integrated optical devices, at almost no extra computational cost. This perturbational approach allows to establish and to quantify guidelines for geometry tolerant devices. Numerical assessment of nonreciprocal wave propagation The coefficients of coupled mode theory for the magnetooptic permittivity contribution allow a classification of the influences of gyrotropy on guided wave propagation. For mirror symmetric waveguides, one identifies the dominant effects of TE phase shift, TM phase shift, and TE/TM polarization conversion, for polar, equatorial, and longitudinal magnetooptic configurations, respectively. Layered equatorial magnetooptic profiles lead to the well known phase shifters for TM modes. Analogously, sliced asymmetric polar magnetooptic profiles yield phase shifts for TE polarized modes. Simulations of rib waveguides with a magnetooptic domain lattice predict effects of the same order of magnitude as the phase shift for TM modes. Phase matching as a condition for complete polarization conversion in longitudinally magnetized waveguides can be realized with selected geometries of raised strip waveguides or embedded square waveguides. Based on coupled mode theory for hybrid fundamental modes, the analysis of the performance of such devices in an isolator setting includes birefringence, optical absorption, and an explicit perturbational evaluation of fabrication tolerances. A magnetooptic waveguide which is magnetized at a tilted angle may perform as a unidirectional polarization converter. The term specifies a device that converts TE to TM light for one direction of propagation, while it maintains the polarization for the opposite direction. A double layer setup with two magnetooptic films of opposite Faraday rotation is proposed and simulated. Designs of three waveguide couplers for applications as isolators/circulators and polarization splitters Three-guide couplers with multimode central waveguides allow for a remote coupling between the outer waveguides. While the power transfer is a truly multimode interference process, one can identify two different regimes where either two or three supermodes dominate the coupling behaviour. Numerical simulations show reasonable agreement between the main coupling features in planar an three dimensional devices. The specific form of the relevant modes suggests the design of integrated optical isolators and circulators. Both planar and three dimensional concepts are investigated. A radiatively coupled waveguide polarization splitter should be designed such that the entire dynamic range of the coupling length variations is exploited. This is easily possible with a three dimensional raised strip configuration. Combination of two magnetooptic unidirectional polarization converters and two radiatively coupled waveguide based polarization splitters leads to a concept for a polarization independent integrated four port circulator device. The simulation predicts a total length of about three millimeters.

Throughout stochastic data processing fields, mean and covariance matrices are commonly employed for purposes such as standardizing multivariate data through decorrelation. For practical applications, these matrices are usually estimated, and often, the data used for these estimates are non-Gaussian or may be corrupted by outliers or impulsive noise. To address this, robust estimators should be employed. However, in signal processing, where complex-valued data are common, the robust estimation techniques currently employed, such as M-estimators, provide limited robustness in the multivariate case. For this reason, this dissertation extends, to the complex-valued domain, the high-breakdown-point class of multivariate estimators called S-estimators. This dissertation defines S-estimators in the complex-valued context, and it defines their properties for complex-valued data. One major shortcoming of the leading high-breakdown-point multivariate estimators, such as the Rocke S-estimator and the smoothed hard rejection MM-estimator, is that they lack statistical efficiency at non-Gaussian distributions, which are common with real-world applications. This dissertation proposes a new tunable S-estimator, termed the Sq-estimator, for the general class of elliptically symmetric distributions—a class containing many common families such as the multivariate Gaussian, K-, W-, t-, Cauchy, Laplace, hyperbolic, variance gamma, and normal inverse Gaussian distributions. This dissertation demonstrates the diverse applicability and performance benefits of the Sq-estimator through theoretical analysis, empirical simulation, and the processing of real-world data. Through analytical and empirical means, the Sq-estimator is shown to generally provide higher maximum efficiency than the leading maximum-breakdown estimators, and it is also shown to generally be more stable with respect to initial conditions. To illustrate the theoretical benefits of the Sq for complex-valued applications, the efficiencies and influence functions of adaptive minimum variance distortionless response (MVDR) beamformers based on S- and M-estimators are compared. To illustrate the finite-sample performance benefits of the Sq-estimator, empirical simulation results of multiple signal classification (MUSIC) direction-of-arrival estimation are explored. Additionally, the optimal investment of real-world stock data is used to show the practical performance benefits of the Sq-estimator with respect to robustness to extreme events, estimation efficiency, and prediction performance. / Doctor of Philosophy / Throughout stochastic processing fields, mean and covariance matrices are commonly employed for purposes such as standardizing multivariate data through decorrelation. For practical applications, these matrices are usually estimated, and often, the data used for these estimates are non-normal or may be corrupted by outliers or large sporadic noise. To address this, estimators should be employed that are robust to these conditions. However, in signal processing, where complex-valued data are common, the robust estimation techniques currently employed provide limited robustness in the multivariate case. For this reason, this dissertation extends, to the complex-valued domain, the highly robust class of multivariate estimators called S-estimators. This dissertation defines S-estimators in the complex-valued context, and it defines their properties for complex-valued data. One major shortcoming of the leading highly robust multivariate estimators is that they may require unreasonably large numbers of samples (i.e. they may have low statistical efficiency) in order to provide good estimates at non-normal distributions, which are common with real-world applications. This dissertation proposes a new tunable S-estimator, termed the Sq-estimator, for the general class of elliptically symmetric distributions—a class containing many common families such as the multivariate Gaussian, K-, W-, t-, Cauchy, Laplace, hyperbolic, variance gamma, and normal inverse Gaussian distributions. This dissertation demonstrates the diverse applicability and performance benefits of the Sq-estimator through theoretical analysis, empirical simulation, and the processing of real-world data. Through analytical and empirical means, the Sq-estimator is shown to generally provide higher maximum efficiency than the leading highly robust estimators, and its solutions are also shown to generally be less sensitive to initial conditions. To illustrate the theoretical benefits of the Sq-estimator for complex-valued applications, the statistical efficiencies and robustness of adaptive beamformers based on various estimators are compared. To illustrate the finite-sample performance benefits of the Sq-estimator, empirical simulation results of signal direction-of-arrival estimation are explored. Additionally, the optimal investment of real-world stock data is used to show the practical performance benefits of the Sq-estimator with respect to robustness to extreme events, estimation efficiency, and prediction performance.

No / PURPOSE. To evaluate whether the Amblyopia and Strabismus Questionnaire (A&SQ) is a suitable instrument for the assessment of vision-related quality-of life (VR-QoL) in individuals with strabismus and/or amblyopia. METHODS. The A&SQ was completed by 102 individuals, all of whom had amblyopia, strabismus, or both. Rasch analysis was used to evaluate the usefulness of individual questionnaire items (i.e., questions); the response-scale performance; how well the items targeted VR-QoL; whether individual items showed response bias, depending on factors such as whether strabismus was present; and dimensionality. RESULTS. Items relating to concerns about the appearance of the eyes were applicable only to those with strabismus, and many items showed large ceiling effects. The response scale showed disordered responses and underused response options, which improved after the number of response options was reduced from five to three. This change improved the discriminative ability of the questionnaire (person separation index increased from 1.98 to 2.11). Significant bias was found between strabismic and nonstrabismic respondents. Separate Rasch analyses conducted for subjects with and without strabismus indicated that all A&SQ items seemed appropriate for individuals with strabismus (Rasch infit values between 0.60 and 1.40), but several items fitted the model poorly in amblyopes without strabismus. The AS&Q was not found to be unidimensional. CONCLUSIONS. The findings highlight the limitations of the A&SQ instrument in the assessment of VR-QoL in subjects with strabismus and especially in those with amblyopia alone. The results suggest that separate instruments are needed to quantify VR-QoL in amblyopes with and without strabismus.

A critical evaluation of the National Curriculum Statement (NCS) was undertaken to uncover strategies for infusing values across the curricula – values that may facilitate the development of spiritual intelligence (SQ) in adolescents. A literature study was conducted to determine whether SQ may be harnessed to cultivate values within an educational context. In addition, moral and spiritual development in adolescence was explored and a case made for values-education. An empirical investigation was undertaken using both a qualitative research design and semi-structured interviews. A purposive sample was used comprising 14 education specialists, principals and Life Orientation teachers from six secondary schools in Gauteng and Mpumalanga provinces. The most important finding was the fact that values-education in the NCS was problematic. The conclusion was thus drawn that teachers should be trained to incorporate values within curriculum activities − values that could engender SQ and, thus, address the moral dilemmas in our schools. / Psychology of Education / M. Ed. (Psychology of Education)