In industrial environments workers can be prone to dangerous situations that may cause harm. In order to prevent accidents and fulfill legislative requirements for safe working condition, a safety system can be needed to be installed in place. In an attempt to bring a principal improvement in the safety standards offered by conventional systems in existence, a radar sensor is proposed for the detection of dangerous situations. This thesis explores the limiting performance of the radar sensor in an industrial safety system. The radar sensor is an FMCW mode MIMO radar and we develop a model to simulate the radar sensor based on its hardware design. The model is utilized to deduce and analyze the performance limits of the radar sensor, by using a Finite Element Method to determine the electromagnetic scattering response of a target in the operating frequency band, 60-64 GHz. Appropriate dielectric and magnetic properties of human tissue is assigned to obtain accurate scattering responses of a human body target. The performance analysis is done by comparing the reflection from various protruding body parts, with the reflection from the torso, over a wide range of postures of the body. Further, CFAR, a common form of detection algorithm is applied on a few of the postures to detect a protruding part the body. Finally, a discussion on the limited performance is made, and potential methods to enhance the performance of the radar sensor in an industrial safety system are suggested. / I industriella miljöer kan arbetare utsättas för farliga situationer vilka kan orsaka skador. För att förhindra olyckor och uppfylla lagstadgade krav för säkra arbetsförhållanden kan säkerhetssystem behöva installeras på plats. I ett försök att åstadkomma en förbättring av de säkerhetsstandarder som erbjuds av konventionella system föreslås en radarsensor för att detektera farliga situationer. Denna avhandling undersöker möjliga begränsningar i prestanda hos en radarsensor, vilken ingår som komponent i ett industriellt säkerhetssystem. Radarsensorn är en MIMO-radar, som arbetar i FMCW-mod, och vi utvecklar en modell för att simulera radarsensorn utgående ifrån dess hårdvarudesign. Modellen används för att härleda och analysera begränsningar i prestanda hos radarsensorn, genom att med hjälp av finita elementmetoden beräkna spridningen av elektromagnetiska vågor från ett radarmål i frekvensbandet 60-64 GHz. Tillämpliga dielektriska och magnetiska egenskaper hos mänsklig vävnad har använts för att erhålla tillförlitliga data på spridningsresponsen för människokroppen. Prestandaanalysen görs genom att jämföra reflektionen från olika utskjutande kroppsdelar med reflektionen från bålen över ett stort antal kroppshållningar. Vidare, CFAR, en vanlig form av detektionsalgoritm tillämpas på några av hållningarna för att detektera utskjutande delar av kroppen. Avslutningsvis diskuteras begränsningarna i prestandan och potentiella metoder för att förbättra radarsensorns prestanda i ett industriellt säkerhetssystem föreslås.

Base erosion in the form of profit shifting has become an increasing concern internationally as well as in South Africa. A significant type of base erosion in South Africa is in the form of excessive interest deductions where income is effectively shifted to a no-tax or low-tax jurisdiction. One of the key developments affecting the South African tax laws was the introduction of provisions that target base erosion and profit shifting. Included in these provisions is section 23M, which limits the deduction of interest paid to persons in whose hands the interest received is not subject to tax in South Africa. It was, however, identified that section 23M may target the same interest risks that the new section 31 thin capitalisation provisions address. Section 23M was said to be the enactment of thin capitalisation. Although one of the purposes of tax treaties is to encourage international trade and investment, there is also discriminatory taxation, which runs counter to that purpose and therefore the prevention of such discrimination is important when dealing with tax treaties. The Organisation for Economic Cooperation and Development’s (OECD) Model Tax Convention contains a handful of special criteria in article 24, which must not lead to different or less favourable treatment with regard to taxation. It was found that the non-discrimination article, in particular articles 24(4) and 24(5), may prevent the application of a thin capitalisation regime if the provisions are in contrast with the OECD non-discrimination provisions. Article 24(4) and article 24(5), however, contain an exception that the non-discrimination provisions would not be applicable provided that the thin capitalisation regimes are compatible with the arm’s length principles of article 9. If section 23M was therefore found to be an arm’s length transaction, the article 24(4) and (5) non-discrimination provisions would without further consideration, not be applicable. It was, however, found that section 23M does not consider the factors that should be considered when an arm’s length transaction is applicable, but merely applies the same formula to each company regardless of the size of the company or the industry sector. As a result of this, it appears as if section 23M is arbitrary in nature and therefore would not represent an arm’s length transaction. The exception would not be applicable and would therefore increase the potential non-compliance with the non-discrimination provision. The objective of this study was to determine whether any aspect of section 23M would be contrary to the OECD guidelines relevant to thin capitalisation and in particular the non-discrimination provisions. It was, however, found that although it appears as if section 23M’s primary focus is on cross-border transactions, the provisions do not directly discriminate on the basis of residence. As a result of the discrimination being indirect discrimination and the fact that the cause of section 23M being applicable is not foreign ownership, but rather due to the creditor not being subject to tax, it was concluded that the OECD non-discrimination provisions would not be applicable to section 23M. / MCom (South African and International Tax), North-West University, Potchefstroom Campus, 2015

Base erosion in the form of profit shifting has become an increasing concern internationally as well as in South Africa. A significant type of base erosion in South Africa is in the form of excessive interest deductions where income is effectively shifted to a no-tax or low-tax jurisdiction. One of the key developments affecting the South African tax laws was the introduction of provisions that target base erosion and profit shifting. Included in these provisions is section 23M, which limits the deduction of interest paid to persons in whose hands the interest received is not subject to tax in South Africa. It was, however, identified that section 23M may target the same interest risks that the new section 31 thin capitalisation provisions address. Section 23M was said to be the enactment of thin capitalisation. Although one of the purposes of tax treaties is to encourage international trade and investment, there is also discriminatory taxation, which runs counter to that purpose and therefore the prevention of such discrimination is important when dealing with tax treaties. The Organisation for Economic Cooperation and Development’s (OECD) Model Tax Convention contains a handful of special criteria in article 24, which must not lead to different or less favourable treatment with regard to taxation. It was found that the non-discrimination article, in particular articles 24(4) and 24(5), may prevent the application of a thin capitalisation regime if the provisions are in contrast with the OECD non-discrimination provisions. Article 24(4) and article 24(5), however, contain an exception that the non-discrimination provisions would not be applicable provided that the thin capitalisation regimes are compatible with the arm’s length principles of article 9. If section 23M was therefore found to be an arm’s length transaction, the article 24(4) and (5) non-discrimination provisions would without further consideration, not be applicable. It was, however, found that section 23M does not consider the factors that should be considered when an arm’s length transaction is applicable, but merely applies the same formula to each company regardless of the size of the company or the industry sector. As a result of this, it appears as if section 23M is arbitrary in nature and therefore would not represent an arm’s length transaction. The exception would not be applicable and would therefore increase the potential non-compliance with the non-discrimination provision. The objective of this study was to determine whether any aspect of section 23M would be contrary to the OECD guidelines relevant to thin capitalisation and in particular the non-discrimination provisions. It was, however, found that although it appears as if section 23M’s primary focus is on cross-border transactions, the provisions do not directly discriminate on the basis of residence. As a result of the discrimination being indirect discrimination and the fact that the cause of section 23M being applicable is not foreign ownership, but rather due to the creditor not being subject to tax, it was concluded that the OECD non-discrimination provisions would not be applicable to section 23M. / MCom (South African and International Tax), North-West University, Potchefstroom Campus, 2015

Thesis (PhD)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: 138La is a very long-lived and low abundant p-isotope. Most p-nuclei with Z > 54 are thought to be produced through photodisintegration of s- and r-process seed nuclei. However, this p-process cannot satisfactorily explain the observed abundance of 138La, and more exotic processes, such as ve + 138Ba → 138La + e− have to be considered. This v-process can reproduce the observed solar abundance of 138La, but the significance of the p-process cannot be ruled out due to very high uncertainties in its predicted reaction rates. These errors have been discussed to be mainly due to the unavailability of the experimental nuclear level densities and radiative strength functions of 138,139La, which are critical ingredients for astrophysical reaction rate calculations based on the Hauser-Feshbach approach. Thus, nuclear physics measurements are necessary to place the nuclear properties on a strong footing, in order to make statements regarding the importance of p- and v-processes. In this research project the experimental nuclear level densities and radiative strength functions of 138,139La were measured below the neutron thresholds. From this new experimental data, the Maxwellian averaged cross sections for the 137La(n, y) and 138La(n, y) reactions, at the p-process temperature of 2.5⇥109 K, were computed with the TALYS code. Using these reaction rates the nucleosynthesis calculations in the O/Ne-rich layers of Type II supernovae were performed. The results imply that the standard p-process still under-produces 138La, which puts the v-process on a very strong footing as the main production process for 138La. / AFRIKAANSE OPSOMMING: 138La is ’n p-isotoop met ’n baie lang halfleeftyd. Daar word tans vermoed dat p-nukiede met Z > 54 geproduseer word deur fotodisintegrasie van sen r-proses saadnukliede. Nogtans verklaar hierdie p-proses die waargenome natuurlike voorkoms van 138La nie behoorlik nie, en meer eksotiese prosesse soos byvoorbeeld ve+ 138Ba → 138La + e− moet in aanmerking geneem word. Hierdie v-proses kan die waargenome natuurlike voorkoms van 138La verklaar, maar die belangrikheid van die p-proses kan nie afgewys word nie weens die onsekerheid in die voorspelde reaksie snelheid. Sodanige onsekerhede word bespreek en word hoofsaaklik toegeskryf aan die gebrek aan eksperimentele vlakdigthede en stralings sterkefunksies van die kerne 138,139La, wat van kritiese belang is vir berekeninge van astrofisiese reaksie snelhede gebaseer op die Hauser-Feshbach benadering. Kernfisiese metings is derhalwe noodsaaklik om die eienskappe van kerne op ’n stewige grondslag te plaas sodat uitlatings gemaak kan word omtrent die belangrikheid van p- en v-prosesse. In hierdie esperimentele navorsingsprojek is die kern vlakdigthede en stralings sterkefunksies van 138,139La onder die neutron reaksiedrumpels gemeet. Die nuwe gemete data maak dit moontlik om die Maxwell-gemiddelde kansvlakke vir die 137La(n, y) en 138La(n, y) reaksies by ’n p-proses temperatuur van 2.5 x 109 K met die TALYS program te bereken. Hierdie reaksie snelhede is daarna gebruik om berekeninge van elementvorming in die O/Ne-ryke lae van Tipe-II supernovas te maak. Die resultate wys uit dat die stadaard p-proses nie genoegsame 138La produseer nie, wat derhalwe die v-proses op ’n baie stewige grondslag plaas as die hoof produksie proses vir 138La.

Background: Cross-sectional survey of ocular biometry and visual function in healthy eyes across the life span of a German population aged 20 to 69 years (n = 218). Subject number in percent per age category reflected the percentage within the respective age band of the population of Leipzig, Germany. Methods: Measurements obtained: subjective and objective refraction, best-corrected visual acuity, accommodation, contrast sensitivity, topography and pachymetry with Scheimpflug camera, axial length with non-contact partial coherence interferometry, and spectral-domain optical coherence tomography of the retina. Pearson correlation coefficients with corresponding p-values were given to present interrelationships between stature, biometric and refractive parameters or their associations with age. Two-sample T-tests were used to calculate gender differences. The area under the logarithmic contrast sensitivity function (AULCSF) was calculated for the analysis of contrast sensitivity as a single figure across a range of spatial frequencies. Results: The results of axial length (AL), anterior chamber depth (ACD) and anterior chamber volume (ACV) differed as a function of the age of the participants (rho (p value): AL −0.19 (0.006), ACD −0.56 (< 0.001), ACV-0.52 (< 0.001)). Longer eyes had deeper ACD (AL:ACD 0.62 (< 0.001), greater ACV (AL:ACV 0.65 (< 0.001) and steeper corneal radii (AL:R1ant; R2ant; R1post; R2post 0.40; 0.35; 0.36; 0.36 (all with (< 0.001)). Spherical equivalent was associated with age (towards hyperopia: 0.34 (< 0.001)), AL (−0.66 (< 0.001)), ACD (−0.52 (< 0.001)) and ACV (−0.46 (< 0.001)). Accommodation was found lower for older subjects (negative association with age, r = −0.82 (< 0.001)) and contrast sensitivity presented with smaller values for older ages (AULCSF −0.38, (< 0.001)), no change of retinal thickness with age. 58 % of the study cohort presented with a change of refractive correction above ±0.50 D in one or both eyes (64 % of these were habitual spectacle wearers), need for improvement was present in the young age-group and for older subjects with increasing age. Conclusion: Biometrical data of healthy German eyes, stratified by age, gender and refractive status, enabled cross-comparison of all parameters, providing an important reference database for future patient-based research and specific in-depth investigations of biometric data in epidemiological research. Trial registration: ClinicalTrials.gov # NCT01173614 July 28, 2010

Thesis (PhD)--Stellenbosch University, 2012. / Please refer to full text for abstract.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Radar Cross Section (RCS) is an important parameter in radar engineering. Often, electrically large structures are of interest in RCS analysis due to the high operating frequencies of radar systems. Simulation of these problems can be more e cient than measurement due to the cost associated with measurement. The Method of Moments/Physical Optics (MoM/PO) hybrid method combines the advantages of the MoM and PO, making it suited to solving electrically large problems that may contain some small complex detail. The requirement for high meshing resolution when analysing some electromagnetic problems, however, signi cantly increases memory requirements. As a result, the hybrid MoM/PO becomes computationally expensive for electrically large problems. In this work, a linear phase term is introduced into the RWG basis function formulation of the MoM/PO hybrid. The addition of the linear phase term allows the use of large triangular mesh elements in the PO region, resulting in the analysis of electrically large problems. The bene t of this formulation is that it allows a reduction in computational cost whilst maintaining the accuracy of the hybrid MoM/PO. This improved hybrid is tested on various planar test cases and results show that it attains the same level of accuracy as the original MoM/PO hybrid. / AFRIKAANSE OPSOMMING: Radardeursnit is 'n belangrike parameter in radaringenieurswese. As gevolg van die hoë frekwensies wat deur baie radarstelsels gebruik word, is elektriesgroot probleme dikwels van belang in die berekening van die radardeursnit van teikens. Die modellering en berekening van die radardeursnit van teikens kan meer kostedoeltre end as metings wees, as gevolg van die beduidende koste van radardeursnitmetings. Die hibriede Moment-Metode/Fisiese-Optika tegniek kombineer die voordele van die twee tegnieke, wat dit geskik maak vir elektries-groot probleme met klein, komplekse detail. Indien die gewone benadering egter gevolg word om 'n hoë resolusie faset-model te gebruik, bly dit berekeningsintensief met groot rekenaar geheuevereistes vir elektries-groot probleme. In hierdie studie word 'n lineêre fase term ingesluit in die formulering van die Rao-Wilton-Glisson (RWG) basisfunksies vorm van die hibriede Moment-Metode/Fisiese-Optika tegniek. Die toevoeging van die lineêre fase term maak dit moontlik om groot driehoekfasette in die Fisiese-Optika gebied te gebruik, wat beteken dat elektries-groot probleme makliker opgelos kan word. Die voordeel van hierdie nuwe formulering is dat die berekeningslas en -tyd verminder word terwyl die akkuraatheid van die oorspronklike hibriede Moment-Metode/Fisiese-Optika tegniek behou word. Hierdie verbeterde hibriede tegniek word getoets aan die hand van verskeie platvlak toetsgevalle en die resultate dui daarop dat die akkuraatheid vergelykbaar is met die van die oorspronklike hibriede Moment-Metode/Fisiese-Optika tegniek.

A series of recent excavations on the 2nd Century AD Antonine frontier forts of the Midland Scottish valley, have produced results which suggest that the army was making its own pottery on an appreciable scale. This was at a time when pottery production was thought to have moved almost exclusively into civilian hands. The possible local ware groups identified by the excavations were largely independent of firm source indicators such as kiln and waster material and the number of available samples was often-small. A program of Neutron Activation and Thin Section petrological analyses was undertaken along with an investigation into Textural Analysis, a facet of the Petrological toolkit. The aim was both to define the site ware groups and a group of specialist vessels thought to be local to Scotland, the Mortaria, and to make statements as to their provenance. Although the Mortaria analysis was limited by problems of sample group size and availability, by improving the objectivity of the statistical handling of the derived data sets and developing methods for the high level study of textural data, the site ware groups were defined successfully at both the "intrall and "inter" site levels. The analyses also furnished interpretations as to the mode and nature of the site production schemes. Through the full analysis of' site Daub samples linked to more traditional provenancing techniques, in all but one case the ware groups could be assigned to the source sites, where contrasting production modes could be identified with military as opposed to civilian production.

Les études de différentes propriétés des paires top-antitop dans l'état final dileptonique sont présentées dans cette thèse. Deux analyses ont été réalisées dans des expériences différentes : l'une à D0 auprès du Tevatron, l'autre dans ATLAS auprès du LHC. Les deux collisionneurs étant différents, les mesures qui y sont réalisées sont complémentaires pour les études des propriétés du top. La première analyse, réalisée dans l'expérience D0, a consisté à faire une mesure simultanée de la section efficace de production des paires top-antitop et du rapport d'embranchement t -> Wb Cette mesure a été réalisée dans le canal dileptonique avec un lot de données correspondant à une luminosité de 5,4 fb⁻¹. Elle a ensuite été combinée avec la mesure réalisée dans le canal semileptonique pour obtenir une précision de 8% sur la section efficace, comparable à la précision des calculs théoriques. La deuxième analyse présentée, réalisée dans l'expérience ATLAS , a consisté à mesurer l'asymétrie de charge du quark top dans le canal dileptonique avec le lot de données enregistré par ATLAS en 2011, soit 4,7 fb⁻¹. Les résultats ont ensuite été combinés avec le résultat du canal semileptonique obtenu avec 1 fb⁻¹. On mesure : A^C(ttbar) = 0,029 +- 0,018 (stat.) +- 0,014 (syst.), ce qui est compatible avec la prédiction du modèle standard de 0,004 +- 0,001.

La recherche en physique des particules recouvre des activités diverses depuis la conception des expériences, la mise en route et le suivi des détecteurs, le traitement des données et leur analyse, jusqu'à la communication des résultats aux scientifiques et au grand public. Le document illustre différentes facettes de cette recherche via: la description de la grille de calcul et de stockage qui permet le traitement des données enregistrées par les expériences du LHC et en particulier par l'expérience ATLAS; une mesure de la section efficace top-antitop avec l'expérience D0 auprès du Tevatron; la description de quelques actions de diffusion des connaissances auprès du grand public.