1,029 research outputs found

    LIPIcs, Volume 261, ICALP 2023, Complete Volume

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    LIPIcs, Volume 261, ICALP 2023, Complete Volum

    Edoardo Benvenuto Prize. Collection of papers

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    The promotion of studies and research on the science and art of building in their historical development constitutes the objective that the Edoardo Benvenuto Association has set itself, since its establishment, in order to honor the memory of Edoardo Benvenuto (1940-1998). The Association in recent years has achieved interesting results by developing various activities such as: organization of national and international meetings, conferences, study days; collaborations with national and foreign research institutions; promotion of the editorial series “Between Mechanics and Architecture"; activation of the portal Bibliotheca Mechanica Architectonica, first “open source” digitized library dedicated to historical research on mechanical and architectural texts. But perhaps the most qualifying initiative was the institution of the Edoardo Benvenuto Prize, arrived in 2019 in its twelfth edition, reserved for young researchers in the field of historical studies on science and the art of building. The awarding of the Prize takes place after an in-depth examination of the texts received by the Association by an international commission of experts. The purpose of this book is to collect and present the most recent studies and publications produced by the winners of the various editions of the Edoardo Benvenuto Prize

    Brain Computations and Connectivity [2nd edition]

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    This is an open access title available under the terms of a CC BY-NC-ND 4.0 International licence. It is free to read on the Oxford Academic platform and offered as a free PDF download from OUP and selected open access locations. Brain Computations and Connectivity is about how the brain works. In order to understand this, it is essential to know what is computed by different brain systems; and how the computations are performed. The aim of this book is to elucidate what is computed in different brain systems; and to describe current biologically plausible computational approaches and models of how each of these brain systems computes. Understanding the brain in this way has enormous potential for understanding ourselves better in health and in disease. Potential applications of this understanding are to the treatment of the brain in disease; and to artificial intelligence which will benefit from knowledge of how the brain performs many of its extraordinarily impressive functions. This book is pioneering in taking this approach to brain function: to consider what is computed by many of our brain systems; and how it is computed, and updates by much new evidence including the connectivity of the human brain the earlier book: Rolls (2021) Brain Computations: What and How, Oxford University Press. Brain Computations and Connectivity will be of interest to all scientists interested in brain function and how the brain works, whether they are from neuroscience, or from medical sciences including neurology and psychiatry, or from the area of computational science including machine learning and artificial intelligence, or from areas such as theoretical physics

    Mouldable Solids: Exploring Organisational Grid Strategies to Enhance Mud Architecture

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    Mud is a material with deep origins in human ecology and vernacular architecture. Despite housing one-third of the world’s population and almost half in developing countries, the application of mud as a building material has diminished over the years, perhaps due to a worldwide application of industrialised building materials and practices, as well as the perception of mud as a primitive material. On the contrary, mud is cheap, reusable and sustainable yet critical challenges relate to material behaviour and performance. The researcher takes the standpoint that mud architecture is a material practice and explores organisational grids consisting of skin and skeleton to enhance structural performance. Three areas of interest combine to demonstrate how mud as a material operates in a contemporary context: (1) The Natural Philosophy of Aristotle and ibn Sina to understand the transitional state of matter and force-form relations; (2) Isaac Newton’s Laws of Motion and Hooke’s Law to understand force-displacement relationships; (3) Information theory to represent parameters and conditions as information in organisational strategies. While mud is of interest, other materials explored include plastic, concrete, clay, and adobe as they categorise as mouldable solids due to their transitional states. Where a careful focus on mud regarding material, form, motion and force, the research deploys the technical with the philosophical to negotiate the capacities of this particular mouldable solid. The hypothesis is that the greater the variance in the skin and skeleton grid, the better the resilience and adaptability a body has due to the complex interconnections between the parts that make up a whole, organising and re-organising to withstand forces. The dissertation celebrates mud as a reconfigurable architectural material rather than static and outdated, allowing for a multi-approach solution to contemporary and standardised materials in the current industrialised context

    Tidal Energy and Coastal Models: Improved Turbine Simulation

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    Marine renewable energy is a continually growing topic of both commercial and academic research sectors. While not as developed as other renewable technologies such as those deployed within the wind sector, there is substantial technological crossover coupled with the inherent high energy density of water, that has helped push marine renewables into the wider renewable agenda. Thus, an ever expanding range of projects are in various stages of development.As with all technological developments, there are a range of factors that can con-tribute to the rate of development or eventual success. One of the main difficulties, when looking at marine renewable technologies in a comparative view to other en-ergy generation technologies, is that the operational environment is physically more complex: Energy must be supplied in diverse physical conditions, that temporally fluctuate with a range of time scales. The constant questions to the iteration to the local ecology. The increased operational fatigue of deployed devices. The financial risk associated within a recent sector.This work presents the continual research related to the computational research development of different marine renewable technologies that were under develop-ment of several institutional bodies at the time of writing this document.The scope has a wide envelopment as the nature of novel projects means that the project failure rate is high. Thus, forced through a combination of reasons related to financial, useful purpose and intellectual property, the research covers distinct projects

    Ortho-Radial Drawing in Near-Linear Time

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    An orthogonal drawing is an embedding of a plane graph into a grid. In a seminal work of Tamassia (SIAM Journal on Computing 1987), a simple combinatorial characterization of angle assignments that can be realized as bend-free orthogonal drawings was established, thereby allowing an orthogonal drawing to be described combinatorially by listing the angles of all corners. The characterization reduces the need to consider certain geometric aspects, such as edge lengths and vertex coordinates, and simplifies the task of graph drawing algorithm design. Barth, Niedermann, Rutter, and Wolf (SoCG 2017) established an analogous combinatorial characterization for ortho-radial drawings, which are a generalization of orthogonal drawings to cylindrical grids. The proof of the characterization is existential and does not result in an efficient algorithm. Niedermann, Rutter, and Wolf (SoCG 2019) later addressed this issue by developing quadratic-time algorithms for both testing the realizability of a given angle assignment as an ortho-radial drawing without bends and constructing such a drawing. In this paper, we improve the time complexity of these tasks to near-linear time. We establish a new characterization for ortho-radial drawings based on the concept of a good sequence. Using the new characterization, we design a simple greedy algorithm for constructing ortho-radial drawings

    LIPIcs, Volume 274, ESA 2023, Complete Volume

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    LIPIcs, Volume 274, ESA 2023, Complete Volum

    Machine learning for the automation and optimisation of optical coordinate measurement

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    Camera based methods for optical coordinate metrology are growing in popularity due to their non-contact probing technique, fast data acquisition time, high point density and high surface coverage. However, these optical approaches are often highly user dependent, have high dependence on accurate system characterisation, and can be slow in processing the raw data acquired during measurement. Machine learning approaches have the potential to remedy the shortcomings of such optical coordinate measurement systems. The aim of this thesis is to remove dependence on the user entirely by enabling full automation and optimisation of optical coordinate measurements for the first time. A novel software pipeline is proposed, built, and evaluated which will enable automated and optimised measurements to be conducted. No such automated and optimised system for performing optical coordinate measurements currently exists. The pipeline can be roughly summarised as follows: intelligent characterisation -> view planning -> object pose estimation -> automated data acquisition -> optimised reconstruction. Several novel methods were developed in order to enable the embodiment of this pipeline. Chapter 4 presents an intelligent camera characterisation (the process of determining a mathematical model of the optical system) is performed using a hybrid approach wherein an EfficientNet convolutional neural network provides sub-pixel corrections to feature locations provided by the popular OpenCV library. The proposed characterisation scheme is shown to robustly refine the characterisation result as quantified by a 50 % reduction in the mean residual magnitude. The camera characterisation is performed before measurements are performed and the results are fed as an input to the pipeline. Chapter 5 presents a novel genetic optimisation approach is presented to create an imaging strategy, ie. the positions from which data should be captured relative to part’s specific geometry. This approach exploits the computer aided design (CAD) data of a given part, ensuring any measurement is optimal given a specific target geometry. This view planning approach is shown to give reconstructions with closer agreement to tactile coordinate measurement machine (CMM) results from 18 images compared to unoptimised measurements using 60 images. This view planning algorithm assumes the part is perfectly placed in the centre of the measurement volume so is first adjusted for an arbitrary placement of the part before being used for data acquistion. Chapter 6 presents a generative model for the creation of surface texture data is presented, allowing the generation of synthetic butt realistic datasets for the training of statistical models. The surface texture generated by the proposed model is shown to be quantitatively representative of real focus variation microscope measurements. The model developed in this chapter is used to produce large synthetic but realistic datasets for the training of further statistical models. Chapter 7 presents an autonomous background removal approach is proposed which removes superfluous data from images captured during a measurement. Using images processed by this algorithm to reconstruct a 3D measurement of an object is shown to be effective in reducing data processing times and improving measurement results. Use the proposed background removal on images before reconstruction are shown to benefit from up to a 41 % reduction in data processing times, a reduction in superfluous background points of up to 98 %, an increase in point density on the object surface of up to 10 %, and an improved agreement with CMM as measured by both a reduction in outliers and reduction in the standard deviation of point to mesh distances of up to 51 microns. The background removal algorithm is used to both improve the final reconstruction and within stereo pose estimation. Finally, in Chapter 8, two methods (one monocular and one stereo) for establishing the initial pose of the part to be measured relative to the measurement volume are presented. This is an important step to enabling automation as it allows the user to place the object at an arbitrary location in the measurement volume and for the pipeline to adjust the imaging strategy to account for this placement, enabling the optimised view plan to be carried out without the need for special part fixturing. It is shown that the monocular method can locate a part to within an average of 13 mm and the stereo method can locate apart to within an average of 0.44 mm as evaluated on 240 test images. Pose estimation is used to provide a correction to the view plan for an arbitrary part placement without the need for specialised fixturing or fiducial marking. This pipeline enables an inexperienced user to place a part anywhere in the measurement volume of a system and, from the part’s associated CAD data, the system will perform an optimal measurement without the need for any user input. Each new method which was developed as part of this pipeline has been validated against real experimental data from current measurement systems and shown to be effective. In future work given in Section 9.1, a possible hardware integration of the methods developed in this thesis is presented. Although the creation of this hardware is beyond the scope of this thesis

    The Fifteenth Marcel Grossmann Meeting

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    The three volumes of the proceedings of MG15 give a broad view of all aspects of gravitational physics and astrophysics, from mathematical issues to recent observations and experiments. The scientific program of the meeting included 40 morning plenary talks over 6 days, 5 evening popular talks and nearly 100 parallel sessions on 71 topics spread over 4 afternoons. These proceedings are a representative sample of the very many oral and poster presentations made at the meeting.Part A contains plenary and review articles and the contributions from some parallel sessions, while Parts B and C consist of those from the remaining parallel sessions. The contents range from the mathematical foundations of classical and quantum gravitational theories including recent developments in string theory, to precision tests of general relativity including progress towards the detection of gravitational waves, and from supernova cosmology to relativistic astrophysics, including topics such as gamma ray bursts, black hole physics both in our galaxy and in active galactic nuclei in other galaxies, and neutron star, pulsar and white dwarf astrophysics. Parallel sessions touch on dark matter, neutrinos, X-ray sources, astrophysical black holes, neutron stars, white dwarfs, binary systems, radiative transfer, accretion disks, quasars, gamma ray bursts, supernovas, alternative gravitational theories, perturbations of collapsed objects, analog models, black hole thermodynamics, numerical relativity, gravitational lensing, large scale structure, observational cosmology, early universe models and cosmic microwave background anisotropies, inhomogeneous cosmology, inflation, global structure, singularities, chaos, Einstein-Maxwell systems, wormholes, exact solutions of Einstein's equations, gravitational waves, gravitational wave detectors and data analysis, precision gravitational measurements, quantum gravity and loop quantum gravity, quantum cosmology, strings and branes, self-gravitating systems, gamma ray astronomy, cosmic rays and the history of general relativity

    Change and continuity at the Roman coastal fort at Oudenburg from the late 2nd until the early 5th century AD. Volume II: The material culture of the south-west corner site

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    In de latere Romeinse periode vormde de Noordzee- en Kanaalregio het decor voor aanvallen van over zee, politieke crisissen, hervormingen van het leger, Germaanse invallen en veranderende verdedigingsstrategieën van het Romeinse Rijk. Woelige tijden dus, waarover weinig literaire bronnen bestaan. De kustforten zijn van onschatbare waarde om de gebeurtenissen van deze periode te begrijpen, maar onderzoek daarvan was schaars. De opgravingen van het Oudenburgse castellum zorgden dan ook voor een belangrijke ommezwaai in onze kennis over die gebeurtenissen, want ze bieden een unieke inkijk in het enige gekende Romeinse stenen fort in Vlaanderen. De opgravingen legden een opmerkelijk goed bewaarde chronologie bloot van vijf opeenvolgende forten, van de late 2de tot de vroege 5de eeuw na Chr. Het is de eerste keer in een kustfort dat de evolutie van midden- tot laat-Romeins fort zo precies kan gedateerd en geïllustreerd worden. Politieke, economische en sociale ontwikkelingen zijn duidelijk te herkennen, dankzij de uitgebreide studie van de stratigrafie en de enorme hoeveelheid aan vondsten. De materiaalstudies, uitgevoerd door specialisten die gebruik maken van verschillende analytische methodes, vormen referenties voor regionaal militair onderzoek en studies van de latere Romeinse periode in de noordwestelijke provincies. De studie van het kustfort van Oudenburg helpt het onderzoek naar verandering en continuïteit en identiteit met betrekking tot het dagelijks leven van de soldaten en de interactie met de ruimere regio. Het is duidelijk dat dit castellum nauw verbonden was met de Britse forten, de Germaanse invloed er geleidelijk aan toenam en het leven in het fort evolueerde naar dat van een gemeenschap van militaire families
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