The aim of this thesis is to reduce the cost of poor quality in the chosen production process. Specifically I focused on the winding lines at the production of rotors, which are components of electronic brake systems (EBS) and heating and ventilation systems of cars. The thesis was worked out in accordance with an announced Six Sigma project in the company. I also dealt with the Six Sigma strategy in the theoretical part. The chosen tools are applied afterwards in the practical part, especially in define, measure and analyse phases. The output of this thesis is an analysis of all possible causes of high scrap ratio in the stated production process. I also proposed to adopt measures for cutting the cost of poor quality in the chosen production process.

The South African primary rebate is governed by Section 6 of the Income Tax Act (58 of 1962). This primary tax rebate entitles taxpayers to a tax-free income portion up to a certain level depending on the rebate amount (also referred to as the tax threshold). The concept of tax thresholds in a tax system in essence adhere to the first tax canon of Smith (1776:676), which suggests that individuals should pay taxes in proportion to each person’s ability to pay tax. The implication of this tax canon is that individuals who have a limited or no ability to pay tax should only be subject to pay tax in relation to their ability. Therefore, before tax can be levied, an amount for the necessities-of-life must be deducted from the taxpayer’s income (Vivian, 2006:85). The primary rebate system thus gives individuals a tax-free income portion which is supposed to first compensate for an individual’s necessities-of-life expenses or put differently the costs to survive. The main purpose of the present study is to critically analyse and compare the fairness of the primary rebates in South Africa in relation to other countries. To meet the main purpose a comparison was done between South Africa’s primary rebate and related government grant programs to that of Brazil and Australia. It was found that South Africa rebate system creates significant vertical and horizontal unfairness and that it compares poorly to the fairer multiple rebate and government grant systems of Brazil and Australia. Accordingly it was recommended that the unified primary rebate system of South Africa is reviewed and brought in line with the multiple rebate systems implemented in countries such as Brazil and Australia. / Dissertation (MCom)--University of Pretoria, 2012. / Taxation / unrestricted

La mosca minadora Liriomyza huidobrensis es una plaga agrícola de importancia mundial, ampliamente distribuida y representa la plaga más dañina en el cultivo de papa en el Perú. El control biológico, que incluye el uso de parasitoides, representa la mejor estrategia para el control de esta plaga. La utilización exitosa de los parasitoides dependerá de nuestro conocimiento de dichos factores, incluyendo las interacciones tritróficas entre plantas hospederas, insectos y parasitoides. Nuestro estudio se realizó sobre el parasitoide Chrysocharis flacilla con el objetivo de evaluar el efecto de las interacciones tróficas en determinados parámetros biológicos como longevidad, supervivencia, producción de progenie, proporción sexual y longitud de la tibia posterior. Se desarrollaron tres sistemas de procedencia del parasitoide: Papa - L. huidobrensis, Haba - L. huidobrensis y Maíz -L. graminivora, cuyos adultos interactuaron con tres asociaciones de prueba idénticas a los sistemas de procedencia mencionados. Todas las evaluaciones se realizaron mediante pruebas Elección y No Elección. C. flacilla presentó una variación intraespecifica en todos los parámetros evaluados. Se encontraron diferencias significativas en su longevidad, supervivencia, proporción sexual y longitud de la tibia posterior luego de interactuar con las distintas asociaciones planta – minador de prueba; asimismo, en su producción de progenie entre las tres procedencias estudiadas. Se menciona la implicancia que puede tener la planta hospedera, así como, el minador hospedero sobre dicha variación en C. flacilla. Finalmente, el parasitoide no presenta preferencia por alguno de sus sistemas de procedencia y las asociaciones tróficas Haba - L. huidobrensis y Maíz -L. graminivora pueden funcionar adecuadamente como hospederos alternos del parasitoide. / ---The leaf miner Liriomyza huidobrensis is an agricultural pest of global importance, widely distributed, representing the most damaging pest in Peru for potato crop. Biological control, including the use of parasitoids, represents the best strategy for controlling this pest. The successful uses of parasitoids will depend on our knowledge of many factors, including tritrophic interactions between host plants, insects and parasitoids. Our study was performed on parasitoid Chrysocharis flacilla in order to assess the effect of trophic interactions in biological parameters such as longevity, survival, production of progeny, sex ratio and posterior tibia length. Three parasitoid origin systems were developed: Potato - L. huidobrensis, Faba bean - L. huidobrensis and Maize -L. graminivora, whose adults interacted with three associations identical to origin systems mentioned. Assessments were made in both No Choice and Choice Tests. We found that C. flacilla has an intraspecific variation in all biological parameters assessed. We found significant differences on longevity, survival, sex ratio and posterior tibia length after interactions with the three different crop – leaf miner associations assessed; moreover, offspring production showed significant differences among the three origin systems studied. We discuss host plant and host leaf miner implications on such intraspecific variation in parasitoid. Finally, C. flacilla does not have any preference for its origin systems; and the trophic associations Faba bean - L. huidobrensis and Maize -L. graminivora can function adequately as alternate hosts of the parasitoid. Keywords: longevity, survival, sex ratio, posterior tibia length, offspring, No choice test, Choice test, plant-leafminer-parasitoid association. / Tesis

This work investigates the optimal measurement matrices that can be used in compressive sensing (CS) image sensors. It also optimizes CMOS current-model pixel cell circuits for CS image sensors. Based on the outcomes from these optimization studies, three CS image senor circuits with compression ratios of 4, 6, and 8 are designed with using a 130 nm CMOS technology. The pixel arrays used in the image sensors has a size of 256X256. Circuit simulations with benchmark image Lenna show that the three images sensors can achieve peak signal to noise ratio (PSNR) values of 37.64, 33.29, and 32.44 dB respectively.

The Swedish housing market has experienced an almost constant increase of housing prices since the economic crisis in the early 90‟s. Many studies have been conducted on the field which have tried to find an explanation to the constant trend and if there is an end in sight. However, this study aims at focusing on the supply/demand relationship in determining the housing prices in the County of Stockholm. The method that was used was both a time series regression and a cross sectional regression, by applying data on the amount of housing that has been constructed per thousand inhabitants in each municipality, the development of housing prices in each municipality and the average annual development of wages. Since there are 26 municipalities in Stockholm County, it would be too time consuming to go through each and every single one of the municipalities, instead the focus was on the 5 municipalities with the highest and lowest construction rate per thousand inhabitants. Thus, we can observe if there is any general difference depending on the construction rate in determining the house price development. The results on the time series regression implies that most of the municipalities housing prices are primarily dependent on the housing construction rate, when construction goes down the prices goes up and vice versa. However, the municipality of Vallentuna had suspicious signs which imply that other factors (then the variables used) are driving the prices up. In the cross sectional regression where both the 5 highest and lowest municipalities with construction rate were regressed together, we can see similar signs as in Vallentuna. It would therefore be interesting to find out what the underlying factors that are driving the prices up in the case of Vallentuna and in the cross sectional analysis.

For an apparatus as big as the pension system, the financial stability is essential. An important feature in the existing pension system is the balance mechanism, which secures the stability of the system. The balance ratio is obtained by dividing the assets by the liabilities. When this ratio drops below 1.0000, it triggers the so-called automatic balancing. While the existing pension system has achieved its goal of being financially stable, it has become clear that the indexation of the pensions during balancing periods has properties that are not optimal. On a short-term perspective the income pension system is exposed to the risk of reacting with a lag, or reacting unnecessarily strong. This gave rise to a new legislative proposal, issued by the government. The goal of the proposal is to obtain a smoother and more up-to-date development of the income pension, i.e. a shorter lag period, without jeopardizing the financial stability. In addition to this it is also desirable to simplify and improve the existing calculation methods. In order to compare the existing calculation methods in the pension system with the new legislative proposal, a simplified model of the existing pension system and the modified version of it, are created. The results of this study shows that the new legislative proposal decreases the volatility in the pensions and it avoids the deepest valleys in the balance ratio. The development of the pension disbursements in the new system has a higher correlation with the development of the average pension-qualifying income than in the current system. Moreover, the results show that the new system has a shorter lag period which makes the income pension system more up- to-date with the current economic and demographic situation. The financial stability is still contained, and the new system also handles variations in the inflation better than the current system / För en apparat så stor som pensionssystemet är den finansiella stabiliteten viktigt. En betydelsefull egenskap i det befintliga systemet är balansmekanismen som säkrar stabiliteten i systemet. Balanstalet beskrivs som pensionssystemets tillgångar dividerat med skulderna. När detta förhållande faller under 1,0000 utlöser det den så kallade automatiska balanseringen. Trots att det nuvarande pensionssystemet har uppnått sitt mål med att vara finansiellt stabilt har det visat sig att indexeringen av pensionerna under balanseringsperioder har egenskaper som inte är optimala. På kort sikt finns det en risk att inkomstpensionssystemet reagerar med en viss tidsfördröjning, eller att den reagerar onödigt starkt. Detta gav upphov till ett nytt lagförslag som är utfärdat av regeringen. Målet med förslaget är att få en jämnare och mer aktuell utveckling av inkomstpensionerna, dvs. en kortare eftersläpningsperiod utan att äventyra stabiliteten i systemet. Utöver detta är det även önskvärt att förenkla och förbättra de nuvarande beräkningsmetoderna. För att kunna jämföra de befintliga beräkningsmetoderna i pensionssystemet med det nya lagförslaget har en förenklad modell av den befintliga pensionssystemet samt den modifierade versionen skapats. Det framgår tydligt av resultaten från denna studie att det nya lagförslaget minskar volatiliteten i pensionerna och undviker de djupaste dalarna i balanstalet. Utvecklingen hos pensionsutbetalningarna i det nya systemet har en högre korrelation med den genomsnittliga pensionsgrundande inkomsten jämfört med det nuvarande systemet. Utöver detta visar resultaten att det nya systemet har kortare eftersläpningsperiod vilket gör inkomstpensionssystemet mer aktuellt. Den finansiella stabiliteten bibehålls och det nya systemet hanterar även fluktuationer i inflationen på ett bättre sätt än i det nuvarande systemet.

This paper sets out to evaluate whether investment recommendations of South African share analysts provide any value to an investor in the Johannesburg Stock Exchange (JSE). The study focuses on the creation of a portfolio based on the recommendations by analysts between December 2002 and July 2010. The monthly returns and respective risk-adjusted returns of this portfolio are compared to those of the SATRIX Top 40 over the same period of time. The paper also evaluates the effectiveness of the SATRIX Top 40 as a performance benchmark by comparing it to a portfolio for shares of family-controlled or owner-managed companies listed on the JSE. The study utilises analyst consensus recommendations, with focus on buy and sell recommendations, to create a buy and hold portfolio that is compared to the SATRIX Top 40. The SATRIX Top 40 is further compared to ten-share portfolio of family-owned or owner-managed companies. The study finds that analysts’ recommendations lead to higher risk-adjusted returns for an investor when compared to the SATRIX Top 40. The returns are even better in a bear market environment when compared the benchmark SATRIX Top 40. It is also found that a portfolio of shares of family-controlled or owner-managed companies performs better than the SATRIX Top 40 and thus provides a better benchmark for an investor. Copyright / Dissertation (MBA)--University of Pretoria, 2010. / Gordon Institute of Business Science (GIBS) / unrestricted

Membrane separation is known as an economic and environmental friendly mode of separation and is used in various types of separation processes. The major challenges regarding membrane separation are the internal and external fouling of the membrane which reduces the permeate flux of the membranes by inducing extra resistance to flow. Synthetic membranes are designed and implemented to separate solutes or particles in a feed stream by rejecting them and permitting the liquid to pass through the membrane pores; however, most of the feed streams, such as wastewaters, contain more than one type of solute. This yields a distribution of particle sizes in the feed. Many wastewaters contain supracolloidal particles (1-100µm). Most membrane separations aim to remove these particles from the feed solution. Wastewaters also contain colloidal particles (0.001-1µm). These particles are less concentrated than supracolloidal particles in the feed but they are more problematic since they are able to penetrate into the membrane pores and cause internal fouling which is the main source of irreversible flux decline. Fouling mechanisms are traditionally classified into four types. Among these mechanisms, standard pore blocking (pore constriction) refers to internal fouling while the other types model external fouling. On the effect of pore geometry, as a morphological factor, studies to date have been limited to external membrane fouling. However, it is believed that up to 80% of the permeate flux can be affected by pore constriction which is caused by particle penetration and deposition into membrane pores (internal fouling). The effect of pore geometry, as a factor, in flux decline due pore constriction of membranes was investigated in this work. Pore constriction by particles was approximated by maximum particle deposition onto the interior wall of the pores and simulated using MATLAB image processing toolbox (MIPT). Sixteen different basic geometries were considered for the simulation of pore constriction by particles. These include circular pores, 3 groups of rectangular, triangular and oval geometries at four different aspect ratios (3, 7, 15 and 30) and three combined geometries of star, cross and a rectangle with rounded ends. The simulation of maximum particle deposition onto pore walls was carried out for a range of particle diameters to pore hydraulic diameters (λ) of 0.1 to the complete rejection of the particle by the pore. As the result of the simulation, the ratio of the available pore cross-sectional area after pore constriction to initial pore cross-sectional area (α) and the ratio of pore channel hydraulic diameter after pore constriction to initial pore hydraulic diameter (β) were measured and recorded. It was observed that for λ<0.2 (small particles compared to pore size) some geometries showed the same values of α and β. However, for λ>0.2, other geometries showed different values of α and β. It was also observed that several geometries reject the particle at different λ ratios. Using the values of α and β, the fluxes of membranes having different pore geometries, after pore constriction by particles, were calculated and compared. These results show that for a very small particle size, compared to pore size, there is no preference for a specific geometry over another; however, for intermediate particle sizes, membranes having triangular and star pore shapes provide higher fluxes compared to other membranes. The effect of pore aspect ratio (PAR) on the flux of membranes after pore constriction was also examined. In order to compare the combined effect of pore geometry on particle rejection and pore constriction, fluxes of membranes having different pore shapes were compared in light of several pore size distributions (PSDs). For this part of the study, the pore geometries of circular, rectangular, triangular and oval were considered at four PARs. Different values for the hydraulic diameter of the largest rejecting pore (D_(H,LRP)) were observed for different geometries. Rectangular pores showed the largest values of D_(H,LRP), at a constant PAR, which affirms their superior rejection behavior. The overall flux of the membranes after pore constriction was determined by a combination of three effects: the position of D_(H,LRP) in the PSD, the pore constriction behavior of the pore geometry and the shape of the PSD. Generally, for the PSDs for which most of the pores in the membrane physically reject the particles, membranes having rectangular pores showed higher fluxes, due to the greater rejection of particles. However, for PSDs for which a major number of pores are constricted by the particles, membranes with triangular pores offered higher flux after membrane pore constriction. The results of this work indicate a new direction for the design of membranes having defined pore geometries.

No description available.

A simple word-recognition task in multitalker babble for clinic use was developed in the course of four experiments involving listeners with normal hearing and listeners with hearing loss. In Experiments 1 and 2, psychometric functions for the individual NU No. 6 words from Lists 2, 3, and 4 were obtained with each word in a unique segment of multitalker babble. The test paradigm that emerged involved ten words at each of seven signal-to-babble ratios (S/B) from 0 to 24 dB. Experiment 3 examined the effect that babble presentation level (70, 80, and 90 dB SPL) had on recognition performance in babble, whereas Experiment 4 studied the effect that monaural and binaural listening had on recognition performance. For listeners with normal hearing, the 90th percentile was 6 dB S/B. In comparison to the listeners with normal hearing, the 50% correct points on the functions for listeners with hearing loss were at 5 to 15 dB higher signal-to-babble ratios.