O consumo de potência em uma Rede Intra-Chip (em inglês, Network-on-Chip – NoC) cresce linearmente com a quantidade de transições de sinais nos pacotes transmitidos através da infra-estrutura de interconexão. Uma forma de minimizar o consumo de potência em um sistema baseado em NoC é reduzir a atividade de transição de sinais nas portas de entrada dos módulos que constituem a NoC. Esta redução pode ser obtida através da utilização de esquemas de codificação de dados. Vários esquemas de codificação foram propostos no final dos anos 90, porém direcionados a arquiteturas de comunicação baseadas em barramentos. Este trabalho investiga a utilização destes esquemas de codificação em sistemas baseados em Networks-on-Chip. Dentre os esquemas encontrados na literatura, quatro foram implementados e avaliados neste trabalho. Este trabalho também apresenta como contribuição original um novo esquema de codificação de dados adequado a NoCs. A estimativa do consumo de potência da NoC é calculada com base em macromodelos que reproduzem a potência consumida em cada módulo interno da NoC, de acordo com a atividade de transição de sinais no tráfego recebido. Estes macromodelos são aqui caracterizados através da simulação elétrica de cada módulo da NoC e dos esquemas de codificação. Para permitir a análise de consumo com tráfegos de aplicações reais, os macromodelos são inseridos em um modelo de mais alto nível de abstração. Este modelo é empregado para analisar o balanço entre redução de potência obtida com a redução da transição de sinais e o consumo extra do esquema de codificação. A maioria dos esquemas de codificação encontrados na literatura reduz efetivamente a atividade de transição de sinais. Porém, o impacto do consumo extra de potência para codificar e decodificar os dados não é avaliado. A avaliação conduzida neste trabalho considera o consumo da codificação/decodificação em uma NoC real, quantificando a redução de consumo obtido com cada esquema de codificação. Devido ao baixo desempenho dos esquemas de codificação existentes, quando aplicados a NoCs, foi desenvolvido um novo esquema, chamado T-Bus-Invert. Os resultados mostram um desempenho superior do T-Bus-Invert quando comparado aos demais esquemas para flits com largura de 8 e 16 bits, e um desempenho similar ao do Bus-Invert com 4 clusters para flits de 32 bits. / The power consumption in Networks-on-Chip grows linearly with the amount of signal transitions in successive data packets sent through this interconnection infrastructure. One option to decrease the power consumption in NoC-based systems is reducing the switching activity at the input ports of NoC modules. This reduction can be achieved by means of data coding schemes. Several schemes were proposed in the nineties. However, all of them address only bus-based communication architectures. This work investigates the use of such data coding schemes in NoC-based systems. Among the coding schemes found in the literature, four were implemented and evaluated in this work. This work also presents a new data coding scheme, named TBus- Invert, suitable for NoCs. Estimations of the NoC power consumption are computed here based on macromodels which reproduce the power consumption on each internal NoC module, according to the transition activity in the input traffic. Such macromodels are characterized through electrical simulations of each NoC module and coding circuits. To enable the evaluation of real applications traffic, such macromodels are inserted in a higher abstraction level model. This model is employed to analyze the trade-off between the power saving due to coding schemes versus the power consumption overhead due to the encoding and decoding modules. Most of the coding schemes proposed in the literature effectively reduce the switching activity, but the overall impact of the power consumption to encode/decode data in the system is not evaluated. The evaluation conducted in this work considers the power consumption to encode/decode data in a real NoC, quantifying the power savings for each coding scheme. Due to the insufficient performances of the existing schemes when applied to NoCs, a coding scheme, T-Bus-Invert, was developed. Results showed superior performance of the T-Bus-Invert compared to all evaluated coding schemes for 8 and 16-bit flits, and similar performance to the 4-cluster Bus-Invert for 32-bit flits.

No description available.

Magister Philosophiae (Land and Agrarian Studies) - MPhil(LAS) / This study explored the production and livelihoods of smallholder farmers in irrigation schemes in South Africa. The particular focus has been on the farming styles of smallholder farmers, the impact of irrigation scheme production on their income and livelihoods, and the issue of smallholder social differentiation. The New Forest irrigation scheme located in Bushbuckridge Local Municipality was used as a case study. The research methodology utilized a combination of extensive and intensive research designs. The farming style approach was compared with the livelihood strategies approach to determine the relationship between the farmers’ approach to farming and their livelihood development trajectory. The underlying assumption is that small-scale irrigation has the potential to make a positive contribution to the livelihoods of farmers. New Forest irrigation farmers face a number of challenges at the irrigation scheme such as neglect by government, inadequate irrigation water, and access to affordable crops inputs. The farmers were not organised to be able to purchase inputs, engage in co-operative marketing, and manage the irrigation scheme. The notion of investing in smallholder irrigation schemes in order to convert smallholders into commercial farmers is unrealistic. Those that were classified as ‘food farmers’, benefit from irrigation development and participation through meeting their household consumption needs. Those classified as ‘employers’, obtained negative gross margins per plot and hired most farm labour. Diversification by employers into other less risky livelihood activities on-farm and off-farm is an option. The ‘profit makers’, make high returns from crop production, and obtained the highest gross margins per plot. This thesis argues that support to farmers in smallholder irrigation schemes should be provided in the context of their farming objectives, and livelihood aspirations which are not only varied but evolve across time and individual circumstances.

Philosophiae Doctor - PhD / This thesis examines livelihoods in the wake of agricultural commercialization under the Revitalization of Smallholder Irrigation Schemes (RESIS) Programme and similar revitalization initiatives within the Olifants River Basin in Limpopo Province. The focus is on contractual joint ventures and strategic partnerships implemented within selected smallholder irrigation schemes. The thesis is based primarily on in-depth empirical studies conducted between October 2003 and March 2009 in three sites located in two Integrated Sustainable Rural Development Programme (ISRDP) poverty nodes namely, Greater Sekhukhune and Vhembe Districts. To a lesser extent, the thesis draws on findings from rapid appraisals of five additional study sites in Greater Sekhukhune District. Research findings showed that the performance of joint ventures and strategic partnerships had so far largely fallen short of expectations. With the exception of a minority of smallholders involved in RESIS-Recharge strategic partnerships, the promise of higher incomes and improved livelihoods had often remained elusive, while debts and potential losses of often meagre household assets loomed large, threatening to erode existing livelihoods and undermine government interventions. This was mainly because ‘viability’ in both the RESIS and RESIS-Recharge phases was narrowly seen in economic and technical terms, such that reduction of transaction costs often entailed the divesting of responsibilities to address issues of rural poverty and inequality. Subsistence production had largely given way to commercially-orientated farming, and weak monitoring of contract formulation and implementation meant that voices of marginalized poor and vulnerable people, particularly women and the elderly, were not being heard. Research findings further revealed that while RESIS-Recharge strategic partnerships increased incomes for a minority of smallholders, such arrangements did not meaningfully improve the productive, managerial and marketing skills of smallholders to ensure their effective participation in agriculture. Rather, strategic partnerships were creating a small class of black ‘arm-chair’ farmers, who played little or no active role and obtained few or no skills in commercial farming but perpetually depended upon and drew incomes from agribusiness initiatives run by externally-based agents. Adjunct to questions of sustainability for these farmers’ ability to participate in commercial farming, the thesis raises the question: What is the rationale for joint ventures and strategic partnerships in the context of South Africa’s Agricultural Sector Strategy objectives for support to black farmers? Contracts lacked mechanisms for equitable distribution of costs and benefits between contracted private partners and targeted smallholders, on the one hand, and the rest of members of local communities, on the other hand. Contracts also lacked provisions for postproject recapitalization of infrastructure and rehabilitation of degraded land. This raised questions about the longer term sustainability of productivity, natural resource base and livelihood security in smallholder irrigation schemes. The conclusion of this thesis is that the challenge of reducing rural poverty and inequality in smallholder irrigation schemes might not be resolved through existing institutional approaches to agricultural commercialization.

Magister Public Health - MPH / Background: South African medical scheme members needlessly purchase high cost originator prescription medicines which attract out of pocket co-payments at pharmacies. This is despite availability of low priced generic medicines that are paid for in full by medical schemes. Co-payments result from misalignment between prices of the dispensed medicine and that of the alternative medicine which appears on the medical scheme's formulary list and for which the scheme is prepared to pay for in full. To establish what factors caused such misalignment, perspectives of medical scheme members and key informants which included pharmacists, regulators and representatives of medical schemes were explored. The study focused on co-payments for prescription medicines dispensed at private sector retail pharmacies in Pretoria, South Africa. Aim: The aim of the study was to explore views about co-payments and identify factors that motivate and influence Pretoria medical scheme members to co-pay when purchasing prescription medicines at pharmacies, despite being insured by medical scheme insurance organizations. Methodology: An exploratory qualitative research study was performed. Semi-structured interviews were conducted among purposefully selected medical scheme members (12) and 9 key informants. Key informants consisted of dispensing pharmacists (6), regulators of health professionals and medical schemes (2) and a senior official (1) with experience in the regulation of medicines and operations within medical scheme organizations. From a total of twelve interviewed medical scheme members, eight were interviewed at preselected retail pharmacies after they had made a co-payment and the other four selected because they did not make a co-payment. To ensure diversity in views about co-payments and related factors, dispensing pharmacists, co-paying and non co-paying medical scheme members were accessed from six pharmacies that are located in two separate locations of different socioeconomic status in Pretoria, that is, the Pretoria East suburban area and Pretoria city centre which is close to Pretoria central station and taxi routes. Three pharmacies were identified from each of the two different geographical locations, one independent and two corporate pharmacies per socioeconomic area. One pharmacist was interviewed from each of the selected pharmacies and medical scheme members were accessed from across the six pharmacies. The remainder of the key informants such as the regulators, were interviewed during office hours at venues of their choice which included areas of work. A pilot study was conducted among medical scheme members and pharmacists to test the applicability of interview tools. All interviews were conducted face-to-face by the researcher and recorded. The electronic record was independently compared with the researcher's enhanced notes for data accuracy. Codes identified during data analysis were derived from the interview notes and recordings and translated into organized text for theme development in a manner that referenced them to each study objective. Themes were arrived at after combining similar codes which were noted as representing a particular description for use during data interpretation and report writing. Ethics: Ethical clearance was sought from the UWC Senate Research Committee and granted. Prior to conducting interviews, written consent was obtained from all participants. Research details were explained and also provided on the participant information sheet wherein voluntary participation was emphasized. Anonymity and confidentiality was maintained throughout. Results: All patients and pharmacists expressed confusion about the medical scheme rules and related co-payments. There were differing co-payment perspectives among scheme members depending on socioeconomic status, with affordability being a key factor among those of lower socio-economic status whilst convenience and lack of comprehensible information about co-payments was prioritised amongst those members of higher socioeconomic status. Key influences on patient's purchasing decisions were health professionals (both doctors and pharmacists), with friends, family members and advertisements less influential. Patients and medical schemes generally preferred to utilise large chain pharmacies and patients, in particular, had a poor perception of the quality of generics. In general, the first prescribed medicine was highly favoured by patients and this influenced medicine preferences during subsequent prescriptions, especially for non communicable disease (NCD) medicines. Pharmacists did not apply the generic substitution policy in a manner that benefited the consumer because the lowest priced generic was frequently not kept as pharmacy stock. Co-payments appeared to create a divide between corporate and independent pharmacies. Some regulators tended to blame patients, pharmacists and medical schemes rather than the lack of adequate enforcement of national policies and regulations. Inadequate monitoring and enforcement of pro-consumer policies were found to be the main factors that contributed to co-payments. Conclusions and Recommendations: The introduction of regulations on minimum requirements for stock available at private sector retail pharmacies should be considered to ensure availability of the lowest priced generic at all times. This would ensure that co-payments are reduced and the desired consumer benefits that should accrue from the existing generic substitution policy are realized and maximized. To prevent perception-based and self-initiated co-payment behavior among consumers, vigorous and continued education about the value and equivalence of generics should be championed at the highest level of government with the execution of this critical responsibility not left to those with profit driven motives. Consumers might benefit from extensive education about the purchasing choices made at pharmacies and, in particular, the negative financial consequences associated with choosing a preferred but highly priced originator versus a low cost generic medicine which is used to treat the same ailment. Enforcement of policies by dedicated government agencies could further protect consumers from preventable high cost of healthcare and of medicines in particular.

No description available.

In this thesis, we consider second-order fully nonlinear partial differential equations of elliptic type. Our aim is to develop computational methods using convergent difference schemes for stationary Hamilton-Jacobi equations with Dirichlet and Neumann type boundary conditions in arbitrary two-dimensional domains. First, we introduce the notion of viscosity solutions in both continuous and discontinuous frameworks. Next, we review Barles-Souganidis approach using monotone, consistent, and stable schemes. In particular, we show that these schemes converge locally uniformly to the unique viscosity solution of the first-order Hamilton-Jacobi equations under mild assumptions. To solve the scheme numerically, we use Euler map with some initial guess. This iterative method gives the viscosity solution as a limit. Moreover, we illustrate our numerical approach in several two-dimensional examples.

MESHWR / Department of Hydrology and Water Resources / See the attached abstract below

Les schémas de subdivision sont largement utilisés pour la génération rapide de courbes ou de surfaces. Des développements récents ont produit des schémas variés, en particulier non-linéaires, non-interpolants ou non-homogènes.Pour pouvoir être utilisés en compression, analyse ou contrôle de données, ces schémas de subdivision doivent être incorporés dans une analyse multiresolution qui, imitant les analyses en ondelettes, fournit une décomposition multi-échelle d'un signal, d'une courbe ou d'une surface. Les ingrédients nécessaires à la définition d'une analyse multiresolution associée à un schéma de subdivision sont des schémas de décimation et de détails. Leur construction est facile quand le schéma de multiresolution est interpolant.Cette thèse est consacrée à la construction de schémas de décimation et de détails compatibles avec un schéma de subdivision le plus général possible. Nous commençons par une construction générique dans le cas d'opérateurs homogènes (mais pas interpolants) puis nous généralisons à des situations non-homogènes et non-linéaires. Nous construisons ainsi des analyses multiresolutions compatibles avec de nombreux schémas récemment développés. L'analyse des performances des analyses ainsi construitesest effectuée. Nous présentons des applications numériques en compression d'images. / Subdivision schemes are widely used for rapid curve or surface generation. Recent developments have produced various schemes, in particular non-linear, non-interpolatory or non-uniform.To be used in compression, analysis or control of data, subdivision schemes should be incorporated in a multiresolution analysis that, mimicking wavelet analyses, provides a multi-scale decomposition of a signal, a curve, or a surface. The ingredients needed to define a multiresolution analysis associated with a subdivision scheme are decimation scheme and detail operators. Their construction is straightforward when the multiresolution scheme is interpolatory.This thesis is devoted to the construction of decimation schemes and detail operators compatible with general subdivision schemes. We start with a generic construction in the uniform (but not interpolatory) case and then generalize to non-uniform and non-linear situations. Applying these results, we build multiresolution analyses that are compatible with many recently developed schemes. Analysis of the performances of the constructed analyses is carried out. We present numerical applications in image compression.

The emphasis of undergraduate mathematics content is centered around abstract reasoning and proof, whereas students' pre-college mathematical experiences typically give them limited exposure to these concepts. Not surprisingly, many students struggle to make the transition to undergraduate mathematics in their first course on mathematical proof, known as a bridge course. In the process of this study, eight students of varied backgrounds were interviewed before during and after their bridge course at BYU. By combining the proof scheme frameworks of Harel and Sowder (1998) and Ko and Knuth (2009), I analyzed and categorized students’ initial proof schemes, observed their development throughout the semester, and their proof schemes upon completing the bridge course. It was found that the proof schemes used by the students improved only in avoiding empirical proofs after the initial interviews. Several instances of ritual proof schemes used to generate adequate proofs were found, calling into question the goals of the bridge course. Additionally, it was found that students’ proof understanding, production, and appreciation may not necessarily coincide with one another, calling into question this hypothesis from Harel and Sowder (1998).