49 research outputs found
Ovoids and spreads of finite classical generalized hexagons and applications
Get PDFOne intuitively describes a generalized hexagon as a point-line geometry full of ordinary hexagons, but containing no ordinary n-gons for n<6. A generalized hexagon has order (s,t) if every point is on t+1 lines and every line contains s+1 points. The main result of my PhD Thesis is the construction of three new examples of distance-2 ovoids (a set of non-collinear points that is uniquely intersected by any chosen line) in H(3) and H(4), where H(q) belongs to a special class of order (q,q) generalized hexagons. One of these examples has lead to the construction of a new infinite class of two-character sets. These in turn give rise to new strongly regular graphs and new two-weight codes, which is why I dedicate a whole chapter on codes arising from small generalized hexagons. By considering the (0,1)-vector space of characteristic functions within H(q), one obtains a one-to-one correspondence between such a code and some substructure of the hexagon. A regular substructure can be viewed as the eigenvector of a certain (0,1)-matrix and the fact that eigenvectors of distinct eigenvalues have to be orthogonal often yields exact values for the intersection number of the according substructures. In my thesis I reveal some unexpected results to this particular technique. Furthermore I classify all distance-2 and -3 ovoids (a maximal set of points mutually at maximal distance) within H(3). As such we obtain a geometrical interpretation of all maximal subgroups of G2(3), a geometric construction of a GAB, the first sporadic examples of ovoid-spread pairings and a transitive 1-system of Q(6,3). Research on derivations of this 1-system was followed by an investigation of common point reguli of different hexagons on the same Q(6,q), with nice applications as a result. Of these, the most important is the alternative construction of the Hölz design and a subdesign. Furthermore we theoretically prove that the Hölz design on 28 points only contains Hermitian and Ree unitals (previously shown by Tonchev by computer). As these Hölz designs are one-point extensions of generalized quadrangles, we dedicate a final chapter to the characterization of the affine extension of H(2) using a combinatorial property
Over and beyond the Primate baubellum Surface: A “Jewel Bone” Shielded in Museums
Get PDFComputed Tomography (CT), mostly used in the medical field, has also recently been involved in Cultural Heritage studies, thanks to its efficiency and total non-invasiveness. Due to the large variety of sizes and compositions typical of Cultural Heritage objects, different X-ray sources, detectors, and setups are necessary to meet the different needs of various case studies. Here, we focus on the use of micro-CT to explore the morphology and shape of a small, neglected bone found inside the clitoris of non-human primates (the baubellum), which we obtained by accessing two prestigious primatological collections of the American Museum of Natural History (New York, NY, USA) and the National Museum of Natural History (Washington, DC, USA). Overcoming methodological limits imposed by the absence of homologous landmarks, we combined the use of the non-invasive 3D micro-CT and a recently released landmark-free shape analysis (the alpha-shape technique) to objectively describe and quantify the shape complexity of scanned primate baubella. Micro-CT provided high-resolution results, overcoming constraints linked to museum policy about non-disruptive sampling and preserving samples for future research. Finally, it proved appropriate as post-mortem sampling had no impact on protected wild primate populations
Back to the future. The future in the past: ICDHS 10th+1 Barcelona 2018: Conference proceedings book
Full text linkObra dedicada a la memòria d'Anna Calvera (1954–2018).ContĂ©: 0. Opening pages -- 1.1 Territories in the scene of globalised design: localisms and cosmopolitanisms -- 1.2 Designing the histories of southern designs -- 1.3 Mediterranean-ness: an inquiry into design and design history -- 1.4 From ideology to methodology: design histories and current developments in post-socialist countries -- 1.5 [100th anniversary of the Bauhaus Foundation]: tracing the map of the diaspora of its students -- 1.6 Design history: gatekeeper of the past and passport to a meaningful future? -- 1.7 Constructivism and deconstructivism: global development and criticism -- 1.8 An expanded global framework for design history -- 1.9 Design museums network: strengthening design by making it part of cultural legacy -- 1.10 Types and histories: past and present issues of type and book design -- 2.1 Design aesthetics: beyond the pragmatic experience and phenomenology -- 2.2 Public policies on design and design-driven innovation -- 2.3 Digital humanities: how does design in today's digital realm respond to what we need? -- 2.4 Design studies: design methods and methodology, the cognitive approach -- 2.5 Vehicles of design criticism -- 3 Open session: research and works in progress (1) -- 3 Open session: research and works in progress (2) -- Addenda: 10th+I keywords mapInternational Committee of Design History and Design Studies. Conference (11a : 2018 : Barcelona, Catalunya),ICDHS is the acronym of the International Committee of DeÂsign History and Design Studies, an organisation that brings together scholars from Spain, Cuba, Turkey, Mexico, Finland, Japan, Belgium, the Netherlands, Brazil, Portugal, the US, TaiÂwan, Canada and the UK. Since 1999, when the Design and Art History departments of the University of Barcelona organised the first edition of the ICDHS, a conference has been held every two years at a different venue around the world. These conferences have had two disÂtinct aims: first, to present original research in the fields of Design History and Design Studies and, second, to include contributions in these fields from non-hegemonic countries, offering a speaking platform to many scientific communities that are already active or are forming and developing. For that reason, the structure of the conferences combines many paralÂlel strands, including poster presentations and keynote speakÂers who lecture on the conferences’ main themes. The 2018 event is rather special. The Taipei 2016 conference was the 10th edition and a commemoration of the ten celebrations to date. Returning to Barcelona in 2018 marks the end of one stage and the beginning of a new one for the Committee. The numbering chosen—“10+1”—also means that Barcelona 2018 is both an end and a beginning in the ICDHS’s own history. The book brings together 137 papers delivered at the ICDHS 10th+1 Conference held in Barcelona on 29–31 October 2018. The papers are preceded by texts of the four keynote lectures and a written tribute from the ICDHS Board to its founder and figurehead, Anna Calvera (1954–2018). The Conference, and the book, are dedicated to her memory
