Overlap and fractional graph colouring

Although a considerable body of material exists concerning the colouring of graphs, there is much less on overlap colourings. In this thesis, we investigate the colouring of certain families of graphs

Brushing the surface: the practice and critical reception of watercolour techniques in England 1850-1880

Twentieth-century art historical research has devoted little attention to the study of watercolour painting techniques and artists’ materials. This is especially true of the period following Turner’s death, when watercolour is said to have been in decline. Yet the period 1850 to 1880 was a period of intense innovation and experimentation, when watercolour painting finally came to be accepted on an equal footing with its rival, the medium of oil. The expansion of annual exhibitions brought dazzling, highly finished works to the attention of the new middle-class buying public, who eagerly scanned the latest press reviews for news and guidance. For the first time, I combine unpublished material from sources including nineteenthcentury colourmen’s archives, conservation records and artists’ descendants’ collections, with an analysis of contemporary watercolour manuals and art critical writing in the press, to give a picture of the dramatic changes in technique which occurred at this time. Brilliant new pigments and improved artists’ papers and brushes flooded onto the market via a growing network of artists’ colourmen. Affordable instruction manuals, aimed at the swelling ranks of amateur artists, were published, their successive editions highlighting the changing character of watercolour practice, in particular the growing use of bodycolour, microscopic detail and new tube pigments. Progressive artists such as John Frederick Lewis, Samuel Palmer, Myles Birket Foster, John William North and Edward Burne-Jones, developed revolutionary ways of incorporating the new artists’ materials into their watercolours, often to great commercial success. Exhibition reviews by critics in the growing number of journals often commented loudly on the bright colouring, minute detail, texture and opaque effects produced by their use of the latest pigments, papers and brushes. The impact made on watercolour painting by improved artists’ materials was farreaching, bringing power and status to a medium which had previously been considered an inferior artform

Raman microscopic and computational studies of artists' pigments and molecular inorganic compounds

This thesis is principally concerned with spectroscopic and computational studies of artists' pigments. Manuscripts, art and archaeological artefacts were examined by Raman microscopy, identifying the pigments and drawing conclusions for historical and conservation purposes. Studies of Anglo Saxon and later manuscripts have shown the Insular palette triumvirate, assumed to be orpiment, red lead and verdigris, to contain red ochre and vergaut, but no verdigris. This remains unchanged until the introduction of lazurite in C.920 AD and vermilion in the 12th century. Lazurite has been erroneously identified on the Lindisfarne Gospels, by the technique of Roosen-Runge. Raman microscopy shows the blue pigments to be exclusively indigo, casting doubt on analyses performed using Roosen-Runge's technique. The Islamic manuscript palette was found to be remarkably consistent across a substantial geographical area over an extended period. It is also very similar to that of early Western manuscripts. Comparison of these results with existing literary sources has shown the latter to be highly inaccurate. The palette of William Blake was examined and compared to results of analysis by False Colour Infrared Photography (FC-IP). The FC-IP technique was determined to be inappropriate for pigment identification. Two significant artefacts were shown to be modern forgeries: a rare Assyrian fresco contains a modern green pigment, and the world famous Vinland map was found to have significant quantities of anatase in the yellow lines. Density Functional Theory methods were applied to the mechanism of decay isomerisation of AS4S4, which was partially clarified, and to the geometries of R2SeX2 (R = CF3, CF2H, CFH2, CH3, CH2CH3, CH(CH3)2, t-Butyl, X = F, Cl, Br, I, At). The most stable geometry was found to be determined by the polarity of the Se-X bonds and the steric and electron-withdrawal effects of the R-group on the C-Se bond strength

Solving hard subgraph problems in parallel

This thesis improves the state of the art in exact, practical algorithms for finding subgraphs. We study maximum clique, subgraph isomorphism, and maximum common subgraph problems. These are widely applicable: within computing science, subgraph problems arise in document clustering, computer vision, the design of communication protocols, model checking, compiler code generation, malware detection, cryptography, and robotics; beyond, applications occur in biochemistry, electrical engineering, mathematics, law enforcement, fraud detection, fault diagnosis, manufacturing, and sociology. We therefore consider both the ``pure'' forms of these problems, and variants with labels and other domain-specific constraints. Although subgraph-finding should theoretically be hard, the constraint-based search algorithms we discuss can easily solve real-world instances involving graphs with thousands of vertices, and millions of edges. We therefore ask: is it possible to generate ``really hard'' instances for these problems, and if so, what can we learn? By extending research into combinatorial phase transition phenomena, we develop a better understanding of branching heuristics, as well as highlighting a serious flaw in the design of graph database systems. This thesis also demonstrates how to exploit two of the kinds of parallelism offered by current computer hardware. Bit parallelism allows us to carry out operations on whole sets of vertices in a single instruction---this is largely routine. Thread parallelism, to make use of the multiple cores offered by all modern processors, is more complex. We suggest three desirable performance characteristics that we would like when introducing thread parallelism: lack of risk (parallel cannot be exponentially slower than sequential), scalability (adding more processing cores cannot make runtimes worse), and reproducibility (the same instance on the same hardware will take roughly the same time every time it is run). We then detail the difficulties in guaranteeing these characteristics when using modern algorithmic techniques. Besides ensuring that parallelism cannot make things worse, we also increase the likelihood of it making things better. We compare randomised work stealing to new tailored strategies, and perform experiments to identify the factors contributing to good speedups. We show that whilst load balancing is difficult, the primary factor influencing the results is the interaction between branching heuristics and parallelism. By using parallelism to explicitly offset the commitment made to weak early branching choices, we obtain parallel subgraph solvers which are substantially and consistently better than the best sequential algorithms

The study of biographical trajectory of portuguese 12th century illuminated manuscript: LECCIONARIUM ALC. 433 from Alcobaça Collection held by The Biblioteca Nacional de Portugal

This thesis presents an interdisciplinary approach to a 12th century illuminated manuscript, a Leccionarium (Alc. 433), produced in Alcobaça Monastery which currently is being preserved at Biblioteca Nacional de Portugal in Lisbon. The aim of the work was to trace the biography of this illuminated manuscript, through the liturgical studies and to obtain the chronological timeline of the use of materials in Alcobaça scriptorium, through centuries. The representative folia of Alc. 433 were characterised with h-XRF, UV-Vis-NIR-FORS, and hyperspectral images. The result indicates that Alc. 433 was produced in the last quarter of the 12th century, followed by addition of some folia in 13th, 14th, and the beginning of 17th century. Materials identification revealed the use of different pigments in different periods: vermilion and minium (red), copper proteinate (bottle green), yellow lake pigments, azurite and lapis lazuli (blue). The PCA study of yellow lake dye reproduction indicates the use of turmeric yellow lake pigment in the initial core. Furthermore, the analysis of iron gall ink also shows that the initial core of Alc. 433 contains the similar ratios of elements with Alc. 11 (primitive manuscript of Alcobaça) thus proved the Alc. 433 was also the produced in the earliest period of the active year of Alcobaça scriptorium; RESUMO: O Estudo da Trajetória Biográfica do Manuscrito Português Iluminado do Século XII: Leccionarium Alc. 433 da Coleção de Alcobaça Detida pela Biblioteca Nacional de Portugal Esta tese apresenta uma abordagem interdisciplinar de um manuscrito iluminado do século XII, um Leccionarium (Alc. 433), produzido no Mosteiro de Alcobaça e que se encontra preservado na Biblioteca Nacional de Portugal em Lisboa. O objetivo deste trabalho foi traçar a biografia deste manuscrito iluminado, através do seu estudo litúrgico e obter a linha cronológica da utilização de materiais no scriptorium de Alcobaça, ao longo dos séculos. Os fólios mais representativos do Alc. 433 foram caracterizados h-XRF, UV-Vis-NIR-FORS e imagens hiperespectrais. O resultado indica que o Alc. 433 foi produzido no último quarto do século XII, e que foi enriquecido com a adição de fólios e/ou cadernos nos séculos XIII, XIV e inícios do século XVII. A identificação dos materiais revelou o uso de diferentes pigmentos em diferentes períodos: vermelhão e minium (vermelho), proteinato de cobre (verde garrafa), pigmento lago amarelo, azurite e lápis-lazúli (azul). O estudo PCA da reprodução do corante lago amarelo indica o uso de açafrão no núcleo inicial do pigmento. Além disso, a análise das tintas de escrita evidenciou uma analogia de composição da tinta ferrogálica utilizada no núcleo inicial do manuscrito Alc.433 e da tinta ferrogálica utilizada no texto do Alc.11 (outro manuscrito produzido nos primeiros anos do scriptorium de Alcobaça) o que comprovou assim que também o Alc. 433 foi produzido na mesma época, isto é, em torno de 1175

Consuming Colour: A Critical Theory of Colour Concerning the Legality and Implications of Colour in Public Space

This thesis investigates the legality of colours and the implications of colours within public spaces. By legality of colours, this thesis references the quality or state of being in accordance and observance of laws that address colour. Colour is a phenomenon of visual light perception described in terms of hue, lightness, and saturation in tandem with the understanding that colour is a vibrating wavelength interpreted through the brain within a complex neurobiological construction. What are the impacts, force, and agency of colours in public spaces? How do colours re(produce) socio-cultural power relationships in neoliberal societies? How do colours contribute to fixing and replicating social, national, and economic differences? In what ways do colours either implicitly or explicitly work as mechanisms of inclusion and exclusion? It is argued that colour is a mechanism for the commodification of public spaces within neoliberal societies. By commodification, this thesis refers to the theory used to describe the process by which something that does not have an economic value is assigned a value and thus illustrating how market values can replace other social values. Colour has been controlled, manipulated, and regulated within public spaces by authoritative powers to psychologically influence human populations. Within this argument, a concern for the effects of colour in public spaces has predominately been overshadowed by a concern for capitalization. An understanding of the historical trajectory of the control of colour immersed with the perspicacity of how colour becomes a device of capitalism is essential. Case studies analysed draw attention to utilizations of colour by dominant forms of authority such as the colour elite nexus and government institutions. Colour is revealed to be a process and is therefore multitudinal and complex. The unravelling of these threads will provide a sharpened sense of colour and the implications of colour within public spaces

The ideological significance of flint in Dynastic Egypt

This thesis examines a little understood aspect of Dynastic Egypt—that of the ideology of flint. Ideology is defined as the way flint is thought of rather than used. This study is unique in examining long term chronological changes in flint ideology against the background of increased metal use, and in using together text, iconography, and archaeology: studies of Egyptian ideology traditionally privilege text. Metaphor theory is employed as an important tool to aid this study. While metaphor is frequently used in Egyptological studies of Egyptian religion, its use is rarely explicit. The dataset brings together unpublished artefacts in British museum collections; a first hand analysis of lithics from Panhesy’s house at Amarna; finds cards from recent excavations at Memphis; and textual sources, several of which have not been considered before in relation to the ideology of flint; as well as published data on Egyptian lithic material. Chronological changes in ideology surrounding flint during the Bronze and Iron Ages, a time of flint decline, are considered. Because the nature of flint decline in Egypt has been assumed rather than known, I attempt to quantify the process. Conclusions show that the ideology of flint was far from static but only loosely related to the kinetic decline of flint. Flint is shown to be connected with the goddesses who are the Eye of Re, with Re himself, with snakes and lions. New facets of flint ideology are uncovered, including the connection of the material with the northern sky and the link between the treatment of New Kingdom Theban flint concretions and the religious landscape of the area

Shetland tweed : identification of its design aesthetic through the characteristics of traditional knowledge

Shetland tweed played a significant part in the Shetland Woollen Industry, competing successfully on a global stage, selling to the luxury tailoring market through the mid-20th century. However, its impact and influence was insufficiently documented to appreciate its key characteristics and design appeal, its tacit knowledge intuitive to traditional craft, and crofting cultures. This practice-based research, therefore, is a form of meta-design setting out to grasp the aesthetic qualities of Shetland tweed. It has mapped and made more explicit the tweed’s particular characteristics as a set of principles for a contemporary cultural design context. The author’s practice, developed from a phenomenological position, related only to what was assimilated from Shetland: its environment, textile archives, museum collections and the nature of the indigenous raw material, Shetland wool. A constructivist grounded theory approach to data generation was adopted to inform a constructivist art methodology to the practical experimentation of knitting and weaving, demonstrating through this research process an experiential understanding of the subject and context. In essence an aesthetic calculus was developed. It is effective in describing how a natural wool palette, particular to Shetland, has been used to produce tweeds that are traditionally Scottish but with aesthetic characteristics that are true to Shetland. This calculus has the potential to benefit manufacturers and designers who want to re-engage with Shetland tweed as a product grounded in the Shetland tradition of making textiles. The research methodology used also opens up the possibility to consider the aesthetic nature of a wider scope of similar textile scenarios where the natural wool palette has traditionally been a dominant factor. New light was shone on the way one particular Shetland tweed manufacturer, T.M. Adie & Sons Ltd, repurposed local textile knowledge to interpret tweed designs. This interpretation represents a form of cultural design activity and is an exemplification of an evolutionary process of safeguarding intangible knowledge rather than being an example of traditional craftsmanship as perceived by Intangible Cultural heritage

New life in an old town’: Wheeler and Sproson, and the post-war reconstruction of Burntisland and Dysart

This thesis explores the work of the important but little-researched architects, Wheeler & Sproson. It aims to set the practice within the broader context of Scottish post-war architectural history and to understand their place among a growing number of architectural practices between the 1950s and 1970s that set out to create a sensitive approach to architectural intervention in historic burghs, blending modern and vernacular forms and materials. Section One comprises two chapters and acts as the contextual basis of the thesis, discussing the key events and ideas that laid the foundation for the practice’s work. Chapter One explores the differing regional and urban approaches adopted in Scotland in the decades following the war, complicating the primarily urban-focused understanding of the period. Chapter Two introduces the growth of a conservation inspired ‘traditionalist’ approach to architecture, bound up with the creation of the Saltire Society and its associated supporters. Section Two of the thesis introduces Wheeler & Sproson and two of their most prominent historic burgh redevelopment projects. Chapter Three examines the academic and employment background of the practice partners, Anthony Wheeler and Frank Sproson. Chapters Four and Five discuss the 1955-75 Burntisland and 1957-77 Dysart redevelopment projects in detail, exploring each phase through an extensive use of original archive material from Historic Environment Scotland’s Wheeler & Sproson Collection. The third and final section of the thesis examines how Wheeler & Sproson’s approaches in Burntisland and Dysart relate to those of their predecessors and contemporaries alike. Chapter Six highlights that the practice was part of a broader context and examines how their work reflects earlier approaches of figures such as Gibberd, Sharp and Sitte. Chapter Seven questions how the work of the practice fits within the context of others operating in Scotland at the time, and how Wheeler & Sproson’s awards successes highlight their prominent position within this movement

The interrelationship of carpet weaving technologies and design in the work of James Templeton and Company, Glasgow, carpet manufacturer, 1890 – 1939

This thesis asks how technical and cultural influences interacted to shape carpet design and manufacture. Primary evidence is drawn from the archives of James Templeton and Company, Glasgow, formerly Scotland’s largest carpet manufacturer, focussing on fifty years of the company’s growth in the early-twentieth century. Factory-woven carpets are underrepresented in current scholarship despite their familiarity. Dominant interests in craft-production and progressive design movements have found little value in styles that Kjetil Fallan has termed “traditionalesque.” The primary aim of the thesis is to reframe carpet research by foregrounding weave structure and design process over pattern style to redress the historiographic bias towards elite forms. Detailed investigation of a broader range of Templeton archive records than used in previous studies has enabled drawings, lithographs, and price lists to be cross-referenced for the purpose of analysing the technical opportunities and constraints that shaped carpet design. These were contextualised by close readings of contemporary trade literature, design instruction manuals, furnishing advice texts, object studies, and original research using the Board of Trade Register of Designs, held by The National Archives (TNA). The concept of technological affordance is adopted from studies of the Social Construction of Technology to analyse how James Templeton and Company used the Chenille Axminster weaving process to make carpets in the early-twentieth century. This thesis’ sociotechnical reading of carpet manufacture intervenes with established methodologies about authorship and style. It proposes a more appropriate approach for studying mechanised carpet weaving. A historically situated reassessment of Templeton’s Chenille Axminster production reveals pattern-storage to be a valued affordance that has been previously overlooked. Examining past training opportunities for carpet designers in Glasgow makes evident the mediation of technological and artistic knowledge in design practice. The first design history of plain-coloured carpets and fresh archival research on the cultural significance of Templeton’s “oriental” designs integrate a more inclusive range of objects into the developing field of carpet history