142 research outputs found

    A 3D Digital Approach to the Stylistic and Typo-Technological Study of Small Figurines from Ayia Irini, Cyprus

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    The thesis aims to develop a 3D digital approach to the stylistic and typo-technological study of coroplastic, focusing on small figurines. The case study to test the method is a sample of terracotta statuettes from an assemblage of approximately 2000 statues and figurines found at the beginning of the 20th century in a rural open-air sanctuary at Ayia Irini (Cyprus) by the archaeologists of the Swedish Cyprus Expedition. The excavators identified continuity of worship at the sanctuary from the Late Cypriot III (circa 1200 BC) to the end of the Cypro-Archaic II period (ca. 475 BC). They attributed the small figurines to the Cypro-Archaic I-II. Although the excavation was one of the first performed through the newly established stratigraphic method, the archaeologists studied the site and its material following a traditional, merely qualitative approach. Theanalysis of the published results identified a classification of the material with no-clear-cut criteria, and their overlap between types highlights ambiguities in creating groups and classes. Similarly, stratigraphic arguments and different opinions among archaeologists highlight the need for revising. Moreover, pastlegislation allowed the excavators to export half of the excavated antiquities, creating a dispersion of the assemblage. Today, the assemblage is still partly exhibited at the Cyprus Museum in Nicosia and in four different museums in Sweden. Such a setting prevents to study, analyse and interpret the assemblageholistically. This research proposes a 3D chaîne opératoire methodology to study the collection’s small terracotta figurines, aiming to understand the context’s function and social role as reflected by the classification obtained with the 3D digital approach. The integration proposed in this research of traditional archaeological studies, and computer-assisted investigation based on quantitative criteria, identified and defined with 3D measurements and analytical investigations, is adopted as a solution to the biases of a solely qualitative approach. The 3D geometric analysis of the figurines focuses on the objects’ shape and components, mode of manufacture, level of expertise, specialisation or skills of the craftsman and production techniques. The analysis leads to the creation of classes of artefacts which allow archaeologists to formulate hypotheses on the production process, identify a common production (e.g., same hand, same workshop) and establish a relative chronological sequence. 3D reconstruction of the excavation’s area contributes to the virtual re-unification of the assemblage for its holistic study, the relative chronological dating of the figurines and the interpretation of their social and ritual purposes. The results obtained from the selected sample prove the efficacy of the proposed 3D approach and support the expansion of the analysis to the whole assemblage, and possibly initiate quantitative and systematic studies on Cypriot coroplastic production

    A 3D Digital Approach to Study, Analyse and (Re)Interpret Cultural Heritage : the Case Study of Ayia Irini (Cyprus and Sweden)

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    This paper focuses on the on-going doctoral research of the writer. Specifically, the topic of this article is on the methodology, the theoretical approach and the first steps of the research. The general aim is the contribution of 3D documentation and the 3D digital approach to the stylistic and typological study of archaeological collections. The study is applied to the collection of the Ayia Irini archaeological excavation (Cyprus). The site was excavated and studied at the beginning of the 20th century by a Swedish archaeological mission and the collection was divided between Cyprus and Sweden. The scope, through the integration of digital technologies, is the three-dimensional documentation of the archaeological material for its (re)interpretation and its metric analysis and comparison. Particularly, the paper will focus on the pipeline and methodology developed for the choice of the sample, its digital acquisition and the analysis of the statues

    The scientific method applied to the reconstructive hypothesis

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    [EN] The literary review of Roman architecture virtual reconstructions elaborated with computer graphics techniques revealed that they often lack scientific rigour, the access to the reconstruction criteria most of the time is not possible and lack the transparency in the process of work and communication. This paper proposes a scientific method based on the architectural and constructive analysis applied to virtual reconstruction field, with an open and transparent process in the validation of the working hypothesis.[ES] Un estudio de las reconstrucciones virtuales de arquitectura romana realizadas con técnicas infográficas, revela que con frecuencia carecen de rigor científico, el acceso a los criterios seguidos para la reconstrucción no es posible, y falta transparencia en el proceso de trabajo y su comunicación. Estas lagunas se traducen en la importancia de determinar una metodología adecuada para las reconstrucciones virtuales, siempre en el ámbito de la arquitectura romana. El método que proponemos en este artículo se basa en el análisis arquitectónico y constructivo, buscando la validación de las hipótesis de trabajo mediante su aplicación, en un proceso abierto y transparente.Vico, L.; Vassallo, V. (2013). The scientific method applied to the reconstructive hypothesis. Virtual Archaeology Review. 4(9):63-69. https://doi.org/10.4995/var.2013.4249636949BARCELO, J.A.; FORTE, M.; SANDERS D.H. (2000): Virtual Reality in archaeology. Oxford: Archeopress.FRAY LORENZO DE S. NICOLAS (1756): "Arte y uso de arquitectura". Parte I. Ed. Placido B. L., Madrid.FRISHER, B. (2012): "Embracing Uncertainty and The London Charter: Case Studies with the 3D Restoration of Ancient Sculpture", On line proceedings of the CAA2012, 26-30 March, Southampton, UK.HEYMAN J. (1967): "Structural Analysis of Masonry", Journal of the Cambridge University Engineering Society, vol. 37.HUERTA FERNANDEZ, S. (2004): "Arcos, bovedas y cupulas. Geometria y equilibrio en el calculo tradicional de estructuras de fabrica". Instituto Juan de Herrera y Escuela superior de Arquitectura, Madrid.MOITINHO DE ALMEIDA, V. y BARCELO, J. A., "Reverse Engineering Archaeological Artefacts", in On line proceedings of the CAA2012, 26-30 March, Southampton, UK.LEVY, R., DAWSON, P. (2009): "Using finite element methods to analyze ancient architecture: an example from the North American Arctic", in Journal of Archaeological Science, nº 36, pp. 2298-2307. http://dx.doi.org/10.1016/j.jas.2009.06.014PARSONS, O. (1965): "Engineers and Engineering in the Renaissance". Ed. Cambridge. The HIT Press, 1965 (reprint of 1939 edition). Cambridge.VICO, L. (2012): "La restauración virtual según la interpretación arquitectónico-constructiva. Metodología y aplicación al caso de la villa de Livia". Tesis doctoral presentada en la Escuela Técnica Superior de Arquitectura de Arquitectura, Universidad Politecnica de Barcelona, 2012.WILSON JONES, M. (2000): "Principles of roman architecture". Ed. Yale University Press. U.S

    Authenticity and cultural heritage in the age of 3D digital reproductions

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    This volume represents the first attempt to collate an organic collection of contributions on authenticity and the digital realm in heritage and archaeology. It analyses the concept of authenticity from different perspectives and with different multidisciplinary contributions, together with theoretical debate. The collection of papers explores the concept of authenticity in a comprehensive way, engaging with theories relating to the commodification of ancient material culture, heritage-making processes, scholarly views and community engagement. These papers also take into account current digital practices for the study of past material culture and how their use affects and redefines interpretation processes in archaeology. This will provide a key reference text for archaeologists, museum and heritage specialists, and other readers interested in authenticity, cultural heritage and 3D reproductions.This book was funded by the EU 7th Framework Programme (7FP), DIGIFACT 625637 Project (http://cordis.europa.eu/project/rcn/187953_ en.html) and ADS3DV 625636 Project (http://cordis.europa.eu/project/ rcn/187952_en.html). The book will be Open Access, thanks to FP7 post-grant Open Access (https://www.openaire.eu/postgrantoapilot)

    A Deep Learning model to segment liver metastases on CT images acquired at different time-points during chemotherapy

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    The aim of this study is to present a fully automatic deep learning algorithm to segment liver Colorectal cancer metastases (lmCRC) on CT images, based on a U-Net structure, comparing nets with and without the transfer learning approach. This is a bi-centric study, enrolling patients who underwent CT exam before (baseline) and after first-line therapy (TP1). Patients were divided into training (using a portion of baseline sequences from both centers) to train the DL model, and two validation sets: one with baseline (valB), and one with TP1 (valTP1) sequences. The reference standard for the automatic segmentations was defined by the manual segmentations performed by an experienced radiologist on the portal phase of the baseline and TP1 CT exam. The best performing model obtained Dice Similarity Coefficient (DSC) of 0.68±0.24, Precision (Pr) of 0.74±0.27, Recall (Re) of 0.73±0.26, Detection Rate (DR) of 93% on the valB, and DSC of 0.61±0.28, Pr of 0.68±0.31, Re of 0.65±0.29 and DR of 88% on the valTP1. These encouraging results, if confirmed on larger dataset, might provide a reliable and robust tool that can be used as first step of future radiomics analyses aimed at predicting response to therapy, improving the management of lmCRC patients

    Hierarchichal-segmented AO in order to attain wide field compensation in the visible on an 8m class telescope

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    We describe the preliminary optimized layout for a partially optimized concept of an optical-8m class VLT-like 2x2 segmented camera where each channel is assisted by an equivalent of an MCAO system where the ground layer correction is commonly employed while the high altitude ones is performed in an open-loop fashion. While we derive the basic relationships among the Field of View and attainable correction with a pre-defined choice for the hardware, we discuss sky coverage and wavefront sensing issues employing natural and artificial references, involving the latest stateof-the-art in the development of wavefront sensing. We show that a flexible approach allow for a compensated Field of View that is variable and can be properly tuned matching the current turbulence situation and the requirement in term of quality of the compensation. A preliminary description of the overall optomechanical package is given as well along with a rough estimates of the efforts required to translates such a concept into reality.Comment: 6 pages, 4 figures, in AO4ELT5 Proceeding

    Ingot Laser Guide Stars Wavefront Sensing

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    We revisit one class of z-invariant WaveFront sensor where the LGS is fired aside of the telescope aperture. In this way there is a spatial dependence on the focal plane with respect to the height where the resonant scattering occurs. We revise the basic parameters involving the geometry and we propose various merit functions to define how much improvement can be attained by a z-invariant approach. We show that refractive approaches are not viable and we discuss several solutions involving reflective ones in what has been nicknamed "ingot wavefront sensor" discussing the degrees of freedom required to keep tracking and the basic recipe for the optical design.Comment: 6 pages, 4 figures, AO4ELT5 Conference Proceeding, 201

    Multiple Spatial Frequencies Pyramid WaveFront Sensing

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    A modification of the pyramid wavefront sensor is described. In this conceptually new class of devices, the perturbations are split at the level of the focal plane depending upon their spatial frequencies, and then measured separately. The aim of this approach is to increase the accuracy in the determination of some range of spatial frequency perturbations, or a certain classes of modes, disentangling them from the noise associated to the Poissonian fluctuations of the light coming from the perturbations outside of the range of interest or from the background in the pupil planes; the latter case specifically when the pyramid wavefront sensor is used with a large modulation. While the limits and the effectiveness of this approach should be further investigated, a number of variations on the concept are shown, including a generalization of the spatial filtering in the point-diffraction wavefront sensor. The simplest application, a generalization to the pyramid of the well-known spatially filtering in wavefront sensing, is showing promise as a significant limiting magnitude advance. Applications are further speculated in the area of extreme adaptive optics and when serving spectroscopic instrumentation where “light in the bucket” rather than Strehl performance is required

    Hyaluronan and Derivatives: An In Vitro Multilevel Assessment of Their Potential in Viscosupplementation

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    In this research work, viscosupplements based on linear, derivatized, crosslinked and complexed HA forms were extensively examined, providing data on the hydrodynamic parameters for the water-soluble-HA-fraction, rheology, sensitivity to enzymatic hydrolysis and capacity to modulate specific biomarkers’ expression in human pathological chondrocytes and synoviocytes. Soluble HA ranged from 0 to 32 mg/mL and from 150 to 1330 kDa MW. The rheological behavior spanned from purely elastic to viscoelastic, suggesting the diversity of the categories that are suitable for restoring specific/different features of the healthy synovial fluid. The rheological parameters were reduced in a diverse manner upon dilution and hyaluronidases action, indicating different durations of the viscosupplementation effect. Bioactivity was found for all the samples, increasing the expression of different matrix markers (e.g., hyaluronan-synthase); however, the hybrid cooperative complexes performed better in most of the experiments. Hybrid cooperative complexes improved COLII mRNA expression (~12-fold increase vs. CTR), proved the most effective at preserving cell phenotype. In addition, in these models, the HA samples reduced inflammation. IL-6 was down-regulated vs. CTR by linear and chemically modified HA, and especially by hybrid complexes. The results represent the first comprehensive panel of data directly comparing the diverse HA forms for intra-articular injections and provide valuable information for tailoring products’ clinical use as well as for designing new, highly performing HA-formulations that can address specific needs

    MAVIS: system modelling and performance prediction

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    The MCAO Assisted Visible Imager and Spectrograph (MAVIS) Adaptive Optics Module has very demanding goals to support science in the optical: providing 15% SR in V band on a large FoV of 30arcsec diameter in standard atmospheric conditions at Paranal. It will be able to work in closed loop on up to three natural guide stars down to H=19, providing a sky coverage larger than 50% in the south galactic pole. Such goals and the exploration of a large MCAO system parameters space have required a combination of analytical and end- to-end simulations to assess performance, sky coverage and drive the design. In this work we report baseline performance, statistical sky coverage and parameters sensitivity analysis done in the phase-A instrument study.Comment: 12 pages, 9 figures, 7 tables. SPIE conference Astronomical Telescopes and Instrumentation, 14 - 18 December 2020, digital foru
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