1,721,030 research outputs found
A maritime archaeology of ships. Innovation and social change in late medieval and early modern Europe
No full textChange is a central concern of archaeology, being imprinted on and variously visible in the material culture of the past. For changes in the ways that people conceived, created and socialised their material world correlate on various levels with changes in their society. This book analyses that dynamic through the lens of technology and innovation in shipping, one of the most sophisticated forms of material expression that many societies achieved. The complexity of watercraft as artefacts reflects need, aspiration and agency in perhaps more explicit ways than almost any other form of material culture. Inherent in their being as objects is a powerful symbolic profile finding expression in identity, as metaphor, as interface between alternate states of existence and in cosmology. Small wonder they are such a powerful medium for investigating materiality in general as well as the changes so important for our understanding of past societies. Until recently it is debatable how far we have capitalised on these qualities, tending to analyse ships as technological phenomena per se rather than relating them to the contexts of their production. This has produced a database of impressive richness but while it constitutes an eloquent record of changes that occurred, it does not explain them. Worse, it is punctuated with a series of enduring puzzles that have long defied explanation. But might these be solved if investigated together with the social contexts in which they were generated? Using recent, underwater archaeological discoveries, this book examines episodes of major technological change stemming from Europe's most significant social transformation of the last millennium, the transition from medieval to modern. The explanatory relationships that emerge not only reaffirm the central role of ships in the development of the modern world but suggest that the boat record is a potent yet under-exploited way of investigating prehistory
High resolution acoustic imagery from a shallowly buried shipwreck: a case study (abstract of poster presented at the EGU General Assembly 2005, Vienna, 24-29 April 2005)
Get PDFShallow water, inter-tidal to immediate sub-tidal (< 5 m), archaeological shipwreck sites present unique challenges to geophysical investigation. Retrieval of reliable data is very difficult through the combination of issues of water column bubble turbulence and the simple geometry of the acoustic. This poster will present an acquisition method that tackles both of these problems through the combination of a purpose built, high frequency (150 kHz) narrow beam (3o) transceiver, Real-Time Kinematic (centimetric accuracy) navigation and a non-motorised deployment method.
The test site for this system was the Grace Dieu (1420), the flagship of Henry V, which was scuttled at its berth in the Hamble River (UK). The site is typically covered by a maximum of 2-5 m of water only being exposed at exceptionally low tides during the spring equinox. The site is partially buried within muddy inter-tidal sediments to a maximum depth of 1.5 m.
The marine survey utilised the 150 kHz transceiver mounted on a catamaran along with an Ashtec marine RTK-GPS navigational system and attitude sensor. The catamaran was towed over the site using divers. Close survey line spacing (< 1 m), centimetric accurate navigation and a theoretically < 10 cm vertical and horizontal resolution enable the accurate presentation of a pseudo-3D acoustic image of this buried wreck. A full and pseudo-3D interpretation of the site has been calibrated against known archaeological site investigation data and an RTK-GPS terrestrial survey.
This poster will demonstrate not only the effectiveness of this system for shallow water archaeological survey but also shallow water detection of any buried object
3D reconstruction of a shallow archaeological site from high-resolution acoustic imagery: The Grace Dieu
Get PDFAcoustic imaging and characterisation of buried objects (and in particular archaeological materials) in shallow-water (<5 m) is often unsuccessful owing to problems related to vessel-induced bubble turbulence and the restricted acoustic geometry of the system. A 2D surveying method that tackles these problems has been tested on the known wreck of the Grace Dieu (1418), Henry V’s flagship, currently buried within the inter-tidal sediments of the Hamble River. The wooden hull is recognisable in the seismic sections as a high amplitude anomaly underlain by an acoustic blanking zone. Close survey line spacing (ca. 1 m) allowed the construction of time slices, identifying the ovate plan of the hull. High, predominantly negative, reflection coefficients suggest this anomaly corresponds to degraded oak timbers buried within the sediment. Combining the data enabled the construction of a (pseudo)-3D image, revealing the dimensions and shape of the hull remains for the first time
The Mary Rose site - geophysical evidence for palaeo-scour marks
Get PDFChirp sub-bottom imaging of scour pits around the original position of the Mary Rose
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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