Abstracts in Afrikaans and English / Aangesien die konsep van kleur vaag en abstrak is, verskil die ervaring én beskrywing daarvan van individu tot individu en van kultuur tot kultuur. Aldus word die waarneem van kleur dikwels ʼn persoonlike en subjektiewe ervaring. In die geval van historiese tale, egter, is die uitdaging om kleurbeskrywing korrek oor te dra, nie sielkundig of esteties van aard nie, maar kultureel, aangesien daar onderliggend aan hierdie tale ʼn unieke linguistiese sisteem gekoppel is. So byvoorbeeld moet die ontleding van Latynse kleurwoorde en die toewysing van relevante betekenismoontlikhede op ʼn besondere wyse aan die Afrikaanse idioom geanker word, sonder om die uniekheid van elk van hierdie tale in te boet. Dit is gevolglik die taak van die navorser om moderne wetenskaplike beskouings oor kleuraanwending met sensitiwiteit en oordeelkundig op die antieke kleursisteme toe te pas. Die bestudering van kleur en kleurgebruik in die Oudheid was vir ʼn lang tyd in omstredenheid gehul. Navorsing in hierdie verband het aanvanklik slegs op die tegniese en argeologiese aspekte van kleurproduksie en -gebruik in die Griekse en Romeinse kuns en argitektuur gefokus. Daarenteen is teoretiese kwessies oor die funksie van kleur in die non-tegniese, estetiese letterkunde selde aangespreek, veral weens die invloed van linguisties-semantiese en kleur-psiogologiese vraagstukke. In hierdie proefskrif val die kollig op Vergilius se keuse en aanwending van dié kleurterme wat beide eksplisiet en implisiet in die Georgica voorkom. Aangesien ʼn sinvolle analise van hierdie digter se kleurgebruik nie tot die Georgica beperk kan word nie, moet die ooreenstemmende terme nie net in sy Eclogae en Aeneïs nie, maar ook in die werke van sy voorgangers, die digters Lucretius en Catullus, betrek word. Uit ʼn beperkte omvang selekteer en gebruik Vergilius kleurwoorde met ʼn delikate presisie van betekenis. Hoewel die stelselmatige ontleding van hierdie terme se betekenismoontlikhede kontekstueel beperk is, toon hierdie benadering in watter mate Vergilius innoverend en verbeeldingryk voorkom. Hierdie inligting dien vervolgens as parateks vir die studie wat volg: Vergilius se gebruik van kleurterme deur die verloop van die vier boeke van die Georgica met die fokus op die letterkundige impak en literêre effekte wat deurgaans as ‘eg Vergiliaans’ beoordeel kan word. . Sou hierdie kleurterme geïgnoreer of net nie raakgelees word nie, kan die leser nie daarop aanspraak maak dat die Georgica waarlik verstaan word nie. Dit is dus die doel van hierdie navorsing om die leser toe te rus met middele tot die vind van ʼn dieper insig in en groter waardering vir hierdie werk as uitnemende poësie. / Since the concept of colour is vague and abstract, the perception of colour differs from individual to individual and from culture to culture to become a highly personal and subjective experience. In the case of historical languages, however, the description of colour is challenging. Conveying colour description correctly is not a psychological or aesthetic exercise, but cultural, as each language has a unique underlying linguistic sensitivity. Consequently, in this dissertation which is written in Afrikaans, the analysis of Latin colour words must be anchored to the Afrikaans idiom in such a unique way as not to detract from the differences in cultural feel between these two languages. Therefore, and in spite of obvious differences, it is the task of the researcher to apply modern scientific views discerningly and sensitively to any ancient colour system. The study of colour and its application in antiquity has long been controversial. Initially research on these aspects of Greek and Roman societies focused only on the technical and archaeological aspects of colour production and its application in their art and architecture. In the wide array of theories regarding linguistic-semantic issues, colour-psychology and also colour aesthetics, theoretical issues regarding the function of colour in non-technical (‘literary’) works were rarely addressed, This dissertation focuses on those colour terms which Vergil uses both explicitly and implicitly in the Georgica. A meaningful analysis of this poet's use of colour must of necessity also include the application of the corresponding terms in his Eclogae and Aeneid, as well as those in the works of his poetic predecessors, Lucretius and Catullus. Selected from a limited range, Vergil applies colour words with a delicate precision of meaning. Although the systematic analysis of these words indicates a range of meaning which can be contextually limited, this approach highlights Vergil’s innovative and imaginative use of colour. With these findings as basis the focus shifts to the consecutive use of colour terms throughout the four books to indicate extraordinary and innovative literary effects which can only be described as ‘thoroughly Vergilian’. If these colour strategies were to escape the reader’s attention, it would result in a poorer understanding of the poem. It is therefore the purpose of this research to equip readers with strategies that will lead to a greater appreciation of the Georgics as exceptional poetry. / Classics and World Languages / D. Litt. et Phil. (Klassieke Studies)

Published Article / This paper focuses on the implementation of a labour performance measuring system at a confectionery company. The computer vision based system is based on the work sampling methodology. It consists of four cameras linked to a central computer via USB extenders. The computer uses a random function in C++ in order to determine when measurements are to be taken. OpenCV is used to track the movement of a target worker's dominant hand at a given work station. Tracking is accomplished through the use of a bandwidth colour filter. The speed of the worker's hand is used to identify whether the worker is busy, idle or out of the frame over the course of the sampling period. Data collected by the system is written into a number of text files. The stored data is then exported to a Microsoft Excel 2007 spread sheet where it is analysed and a report on the labour utilisation is generated.

This study investigates possible connections between shapes, colour, lines, contrast and perceived traits of game characters from their appearance. The study is based on nine pictures of game characters where the characters were interpreted using formal analysis based on theories of shapes, lines and colour components such as hue, value and saturation. A survey was also conducted with 73 respondents who specified each character’s traits with three words. The study shows that there is a larger connection between shapes and characteristics than colour, where the descriptions of the characters were more scattered. Lines, contrast and warm and cool colours generally do not have any noticeable effect on the result. / I denna studie undersöks eventuella samband mellan former, färg, linjer, kontrast och egenskaper som uppfattas kring spelkaraktärer utifrån sitt utseende. Studien utgår ifrån nio bilder av spelkaraktärer där karaktärerna tolkats i en formell analys utifrån teorier om form, linjer och färgens beståndsdelar så som nyans, ljusstyrka och mättnad. En undersökning utfördes även på 73 respondenter som fick specificera varje karaktärs egenskaper med tre ord. Studien visar att det finns ett större samband mellan former och karaktärsdrag, än färger där beskrivningen av karaktärerna var mer splittrad. Linjer, kontrast och varma och kalla färger har i allmänhet inte haft någon större inverkan på resultatet.

Difficulties in controlling and forecasting avocado fruit ripening and the highly perishable nature of the crop once harvested, are the major causes of concern for avocado traders. In particular, the simultaneous presence of many suppliers may account for increased fruit variability during ripening. Avocado is a climacteric fruit with consistent ethylene production after harvest which is also related to high perishability. However, the mechanisms regulating ethylene biosynthesis and mesocarp softening are not completely understood. In order to study such effects, avocado fruit from different growing areas and harvested at various maturity stages, were investigated and the biochemical and physiological changes during ripening at both 18 and 23°C were studied. Mesocarp softening and fatty acid content discriminated fruit maturity and growing area, respectively, whereas C7 sugars (D-mannoheptulose and perseitol) discriminated length of fruit shelf life. For the first time, oleic acid content presents in the oil mesocarp was found to depend on fruit sources making of this a suitable indicator of avocado fruit growing area. In contrast, sugar content declined along fruit maturity and ripening. In particular the mannoheptulose presents in avocado mesocarp might be use to estimate avocado fruit shelf life. Indeed, fruit harvested late in season were found to have a lower C7 content than earlier harvest fruit and a faster softening, regardless fruit source. However, sugars content changed between growing area, thus a general C7 threshold defining fruit storability seems to be not definable. Furthermore, other possible indicators of fruit maturity and/or ripening stage have been searched in the cell wall constituents of avocado mesocarp. Thus, the structural carbohydrates profile of avocado mesocarp investigated with a new immunological method changed during ripening and harvest time (early and late season), suggesting a possible effect of cell wall composition on fruit ripening regulation. Also, the possible use of ethylene application in reducing the high heterogeneity noted on imported fruit from South Africa was also evaluated through different consignments. Results showed ethylene efficacy changed depending on harvest time and fruit dimension with less efficacy of the treatment on fruit harvested at the end of the season and characterised by smaller size.One of the most commercialized avocado cultivars, Hass, is peculiar in that its skin colour changes from green to deep purple as ripening progresses. The most common ripening indicator of avocado fruit is the mesocarp firmness and the destructive nature of this evaluation increases losses in the avocado industry. The availability of a non-destructive indicator of fruit ripening represents an important advantage for avocado consumers and importers. Thus, the possible relationship between mesocarp softening, skin colour were objectively evaluated (C*, L*, and H°), and the main pigment, cyanidin 3-O-glucoside, was investigated. Cyanidin 3-Oglucoside was confirmed to be the main anthocyanin present in avocado cv. Hass peel, regardless of preharvest factors. However, differences in its content were noted between shelf life temperatures. A higher relationship between hue angle and firmness was detected in late harvest fruit, whereas no correlation was found between anthocyanin content and firmness. Avocado skin is also involved in defence mechanisms due to the presence of antifungal and phenolic compounds. These phenolic compounds represent a natural protection against pathogenic infections and seem to be down regulated during ripening. The main phenolics were identified and quantified, using a new analytical method which was validated and optimised. Epicatechin, chlorogenic acid and procyanidin B2 were found to be present in the skin tissue and quantified using this assay and found to vary during shelf life and seasons. Although phenolics were present in minor amounts, in avocado pulp they are involved in mesocarp discoloration incidence, and therefore with fruit postharvest quality. Due to a lack of information, a new straightforward method for the identification and quantification of the main phenolics present in avocado mesocarp was developed. Finally, a commercial trial was undertaken to ensure that the results obtained in the laboratory can be reproduced in the market place. In conclusion, postharvest markers can define avocado fruit maturity and growing area and give guidelines in the control of avocado shelf life. Moreover, new methods for the investigation of the phenolic profiles (peel and mesocarp) and the characterisation of cell wall structures can be further tools in the management of avocado fruit postharvest quality.

Many real-world optimisation problems are discrete in nature. Although recent rapid developments in computer technologies are steadily increasing the speed of computations, the size of an instance of a hard discrete optimisation problem solvable in prescribed time does not increase linearly with the computer speed. This calls for the development of new solution methodologies for solving larger instances in shorter time. Furthermore, large instances of discrete optimisation problems are normally impossible to solve to optimality within a reasonable computational time/space and can only be tackled with a heuristic approach. In this thesis the development of so called matheuristics, the heuristics which are based on the mathematical formulation of the problem, is studied and employed within the variable neighbourhood search framework. Some new variants of the variable neighbourhood searchmetaheuristic itself are suggested, which naturally emerge from exploiting the information from the mathematical programming formulation of the problem. However, those variants may also be applied to problems described by the combinatorial formulation. A unifying perspective on modern advances in local search-based metaheuristics, a so called hyper-reactive approach, is also proposed. Two NP-hard discrete optimisation problems are considered: 0-1 mixed integer programming and clustering with application to colour image quantisation. Several new heuristics for 0-1 mixed integer programming problem are developed, based on the principle of variable neighbourhood search. One set of proposed heuristics consists of improvement heuristics, which attempt to find high-quality near-optimal solutions starting from a given feasible solution. Another set consists of constructive heuristics, which attempt to find initial feasible solutions for 0-1 mixed integer programs. Finally, some variable neighbourhood search based clustering techniques are applied for solving the colour image quantisation problem. All new methods presented are compared to other algorithms recommended in literature and a comprehensive performance analysis is provided. Computational results show that the methods proposed either outperform the existing state-of-the-art methods for the problems observed, or provide comparable results. The theory and algorithms presented in this thesis indicate that hybridisation of the CPLEX MIP solver and the VNS metaheuristic can be very effective for solving large instances of the 0-1 mixed integer programming problem. More generally, the results presented in this thesis suggest that hybridisation of exact (commercial) integer programming solvers and some metaheuristic methods is of high interest and such combinations deserve further practical and theoretical investigation. Results also show that VNS can be successfully applied to solving a colour image quantisation problem.

This thesis investigates the problem of sensors used with mobile robots. Firstly, a colour sensor is considered, for its ability to detect objects having the three primary colours Red, Green and Blue (RGB). Secondly, an accelerometer was investigated, from which velocity was derived from the raw data using numerical integration. The purpose of the design and development of the sensors was to use them for robotic navigation and collision avoidance. This report presents the results of experiments carried out on the colour sensor and the accelerometer. A discussion of the results and some conclusions are also presented. It proved feasible to achieve the goal of detecting colours successfully but only for a limited distance. The accelerometer proved reliable but is not yet being applied in real time. Both the colour sensor and the accelerometer proved to be inexpensive. Some recommendations are made to improve both the colour sensor and the accelerometer sensors.

Magistrantūros studijų baigiamajame darbe pateikiami jogurto, praturtinto liofilizuotomis daržovėmis, fizikinių rodiklių (klampumo, rišlumo, konsistencijos, tvirtumo ir rūgštingumo) bei juslinių savybių tyrimų rezultatai. Darbo objektas – 3,5 % riebumo ekologiškas jogurtas, kuris buvo pagardintas liofilizuotomis daržovėmis, prieskoniniais augalais ir pievagrybiais. Buvo paruošti 6 jogurto su priedais variantai: I var. (kontrolinis) – be priedų; II var. – pomidorų, žaliųjų bazilikų milteliai, druska; III var. – pomidorų, žaliųjų bazilikų, svogūnų milteliai, druska; IV var. – pomidorų, svogūnų milteliai, druska; V var. – paprikų, dašio milteliai, druska; VI var. – pievagrybių, svogūnų milteliai, druska. Darbo metodai: jogurtų spalva matuota spalvos analizatoriumi ColorFlex 45˚/0˚ (HunterLab, JAV). Šviesos atspindžio režimu matuoti parametrai: L*, a* ir b*. Jogurto tekstūra įvertinta tekstūros analizatoriumi TA.XT plus (Stable Micro Systems, JK). Tyrimo metu naudotas atgalinio išspaudimo 35 mm diskas bei 50 mm skersmens stiklinaitė. Nustatyti tyrimo parametrai: disko judėjimo greitis prieš bandymą – 1,0 mm s-1, greitis bandymo metu – 1,0 mm s-1, greitis po bandymo – 10,0 mm s-1. Jogurto juslinėms savybėms įvertinti naudotas aprašomasis juslinės analizės metodas. Buvo nustatyti tokie jusliniai rodikliai: skonis, kvapas, konsistencija, išvaizda ir spalva. Jie įvertinti naudojant intervalines 5 balų skales. Juslines jogurto savybes vertino 6 vertintojai, kurie turėjo užpildyti... [toliau žr. visą tekstą] / Master‘s thesis presents physical properties (viscosity, firmness, consistency, cohesiveness and acidity) and sensory analysis results of yoghurt with lyophilised vegetables. Object of the research: 3.5 % fat yoghurt enriched with lyophilised vegetables, herbs and mushrooms. Six samples of yoghurt were produced. (1) variant (control) was natural yoghurt without any vegetables; (2) variant was made by adding tomatoes, green basil powder, salt; (3) variant of yoghurt contained tomatoes, green basil, onions powder and salt; (4) variant was enriched with tomatoes, onion powder, salt; (5) test variant was made with red peppers, summer savoury powder, salt; (6) variant was yoghurt enriched with mushrooms, onion powder and salt. Research methods: Visual colour of yoghurts was measured by using a Hunter Lab Colour Measurement System Model Color Flex. 45/0 (Hunter Associates Laboratory, Inc.,USA) on the L*a*b* scale. A TA.XT Plus Texture Analyser (Stable Micro Systems Ltd., England) was used to analyse the textural properties of yoghurt samples through simple compression test, using back extrusion 35 mm cell disk and 50 mm back extrusion container. TA settings: Pre – Test speed: 1.00 mm/s, Test speed: 1.00 mm/s, Post – Test speed: 10 mm/s. The descriptive sensory analysis method was applied to assess the following sensory properties of yoghurt: taste, odour, consistency, appearance and colour. The sensory properties were analysed by six tasters who were asked to fill in the... [to full text]

A new range of multi-plankton biogeochemical models have recently been developed, designed to advance our understanding of the ocean carbon cycle to improve predictions of its future influence on climate. Synoptic measurements of the different phytoplankton communities are required to validate and ultimately improve such models. Measuring ocean colour from satellite is the only method currently available for synoptically monitoring wide-area properties of ocean ecosystems, such as phytoplankton chlorophyll biomass. Recently, a variety of bio-optical methods have been established that use satellite data to identify and differentiate between either phytoplankton functional types (PFTs) or phytoplankton size classes (PSCs). In this thesis, several of these techniques were evaluated against in situ observations (6504 samples) to determine their ability to detect dominant phytoplankton size classes (micro-, nano- and picoplankton). Results show that spectral-response, ecological and abundance-based approaches can all perform with similar accuracy. However, abundance-based approaches provide better spatial retrieval of PSCs. Based on insights into the abundance-based models, and by utilising a large pigment database, a new three-component model was developed which calculates the fractional contributions of three phytoplankton size classes (micro-, nano- and picoplankton) to the overall chlorophyll-a concentration. Using a globally representative, independent, coupled pigment and satellite dataset the model estimates fractional contributions with a mean accuracy of 9.2 % for microplankton, 17.1 % for nanoplankton and 16.1 % for picoplankton. The effect of optical depth on the model parameters was also investigated and explicitly incorporated into the model. Using the three-component model, the two-component absorption model of Sathyendranath et al. (2001) and Devred et al. (2006) was extended to three-component populations of phytoplankton, namely, pico-, nano- and microplankton. The new model infers total and size-dependent phytoplankton absorption as a function of the total chlorophyll-a concentration. A main characteristic of the model is that all the parameters that describe it have biological or optical interpretation. The three-component model performs better than the two-component model, at retrieving total phytoplankton absorption. Accounting for the contribution of pico- and nanoplankton, rather than the combination of both used in the two-component model, improved significantly the retrieval of phytoplankton absorption at low chlorophyll-a concentrations. The three-component model was applied to a decade of ocean colour observations. In the equatorial region of the Pacific and Indian Oceans, phytoplankton size class anomalies (% total chlorophyll-a) were highly correlated with indices of both the El Niño (La Niña) Southern Oscillation and the Indian Ocean Dipole. Furthermore, in these regions, micro- and nanoplankton size class anomalies were negatively correlated with anomalies of the sea surface temperature, sea surface height and stratification. Whereas, the picoplankton size class anomalies were positively correlated with these physical variables. Results from this thesis indicate that phytoplankton size class can be retrieved from Earth Observation with reasonable accuracy. It is recommended that such information can now be assimilated into multi-plankton biogeochemical models, or alternatively, verify them.

I argue that conscious visual experience consists in a direct and noninferential grasp of the way one’s current perceptual contact with the environment poises one to pursue various intentional plans, goals and projects. I show that such a view of visual consciousness is supported by current work in cognitive neuroscience, affords a compelling account of colour perception, and suggests a way to bridge the ‘explanatory gap’ between consciousness and the language of the natural sciences. In chapter 1, I examine the reasoning that leads to the appearance of an explanatory gap between the phenomenal and the physical in more detail, and set out the constraints on a solution that our discussion of the problem has imposed. I then sketch the two rival takes on the relationship between perception and action mentioned above – adjudicating between these two theories (and finding in favour of the action-space view) is the task of the next two chapters, and is a recurring theme throughout. Chapter 2 moves on to discuss some recent work in the neuropsychology of vision and what it might suggest about the functional role of conscious vision, and the first half of chapter 3 considers two puzzle cases concerning colour perception. Each of these discussions turns out to constitute a source of support for the actionspace view that visual perception consists in a grasp of the practical consequences of sensation, and the second half of chapter 3 sets out this view and responds to an initial range of questions and objections it might face. Chapter 4 illustrates our view via a discussion of colour perception, and chapter 5 discusses the type of grasp of practical consequences that is necessary for perceptual sensitivity to issue in conscious experience. By chapter 6, we are in a position to see how the action-space approach can help close the explanatory gap for phenomenal consciousness, and our final chapter sets out how I think this should be done. I conclude with a brief discussion of further questions and prospects for the action-space approach.

This thesis develops and explores a constitutive approach to colour vision, which serves as an alternative to the standard experiential view of colour vision operating in the philosophy of colour. The approach seeks to describe the nature or essence of colour vision qua psychological kind. I argue that it is constitutive of colour vision that an organism possesses the ability to achieve colour constancy. An important feature of my account is that colour constancy is characterised as the ability to discriminate differences in surface reflectance properties across changes in illumination conditions. This differs from the standard ‘appearance invariance view’, which characterises colour constancy by appealing to the phenomenology of apparent colour. I consider an important objection to the appearance invariance view posed by the argument from illumination, which might also seem to carry over to the reflectance discrimination view. The objection is based on the claim that in standard cases of colour constancy the phenomenology of apparent colour is partly illumination-dependent. I argue that the reflectance discrimination view is perfectly able to accommodate this point. As a case study in applying the constitutive approach to illuminate the distinctive nature of colour vision, I argue that a vivid feature of our ordinary experience of colour known as categorical perception should be dissociated from our colour vision abilities. Although colour ontology often is not at the forefront of discussion, these constitutive theses support the ontological view of colour known as reflectance physicalism. I critique the argument from colour similarity, which many take to pose the greatest threat to reflectance physicalism. The thrust of the argument is that colours phenomenally appear to stand in similarity relations that do not correlate with the similarities that are evident among reflectance properties. This argument lacks much force, however, as it fails to acknowledge the extreme context sensitivity of similarity and the presentation sensitivity of our knowledge of similarities.