Assessing 3D metric data of digital surface models for extracting archaeological data from archive stereo-aerial photographs.

Archaeological remains are under increasing threat of attrition from natural processes and the continued mechanisation of anthropogenic activities. This research analyses the ability of digital photogrammetry software to reconstruct extant, damaged, and destroyed archaeological earthworks from archive stereo-aerial photographs. Case studies of Flower's Barrow and Eggardon hillforts, both situated in Dorset, UK, are examined using a range of imagery dating from the 1940s to 2010. Specialist photogrammetric software SocetGXP® is used to extract digital surface models, and the results compared with airborne and terrestrial laser scanning data to assess their accuracy. Global summary statistics and spatial autocorrelation techniques are used to examine error scales and distributions. Extracted earthwork profiles are compared to both current and historical surveys of each study site. The results demonstrate that metric information relating to earthwork form can be successfully obtained from archival photography. In some instances, these data out-perform airborne laser scanning in the provision of digital surface models with minimal error. The role of archival photography in regaining metric data from upstanding archaeology and the consequent place for this approach to impact heritage management strategies is demonstrated

Insights into Cross-Kingdom Plant Pathogenic Bacteria

Plant and human pathogens have evolved disease factors to successfully exploit their respective hosts. Phytopathogens utilize specific determinants that help to breach reinforced cell walls and manipulate plant physiology to facilitate the disease process, while human pathogens use determinants for exploiting mammalian physiology and overcoming highly developed adaptive immune responses. Emerging research, however, has highlighted the ability of seemingly dedicated human pathogens to cause plant disease, and specialized plant pathogens to cause human disease. Such microbes represent interesting systems for studying the evolution of cross-kingdom pathogenicity, and the benefits and tradeoffs of exploiting multiple hosts with drastically different morphologies and physiologies. This review will explore cross-kingdom pathogenicity, where plants and humans are common hosts. We illustrate that while cross-kingdom pathogenicity appears to be maintained, the directionality of host association (plant to human, or human to plant) is difficult to determine. Cross-kingdom human pathogens, and their potential plant reservoirs, have important implications for the emergence of infectious diseases

A Survey of Geometric Analysis in Cultural Heritage

We present a review of recent techniques for performing geometric analysis in cultural heritage (CH) applications. The survey is aimed at researchers in the areas of computer graphics, computer vision and CH computing, as well as to scholars and practitioners in the CH field. The problems considered include shape perception enhancement, restoration and preservation support, monitoring over time, object interpretation and collection analysis. All of these problems typically rely on an understanding of the structure of the shapes in question at both a local and global level. In this survey, we discuss the different problem forms and review the main solution methods, aided by classification criteria based on the geometric scale at which the analysis is performed and the cardinality of the relationships among object parts exploited during the analysis. We finalize the report by discussing open problems and future perspectives

A mathematical model of quorum sensing regulated EPS production in biofilm communities

<p>Abstract</p> <p>Background</p> <p>Biofilms are microbial communities encased in a layer of extracellular polymeric substances (EPS). The EPS matrix provides several functional purposes for the biofilm, such as protecting bacteria from environmental stresses, and providing mechanical stability. Quorum sensing is a cell-cell communication mechanism used by several bacterial taxa to coordinate gene expression and behaviour in groups, based on population densities.</p> <p>Model</p> <p>We mathematically model quorum sensing and EPS production in a growing biofilm under various environmental conditions, to study how a developing biofilm impacts quorum sensing, and conversely, how a biofilm is affected by quorum sensing-regulated EPS production. We investigate circumstances when using quorum-sensing regulated EPS production is a beneficial strategy for biofilm cells.</p> <p>Results</p> <p>We find that biofilms that use quorum sensing to induce increased EPS production do not obtain the high cell populations of low-EPS producers, but can rapidly increase their volume to parallel high-EPS producers. Quorum sensing-induced EPS production allows a biofilm to switch behaviours, from a colonization mode (with an optimized growth rate), to a protection mode.</p> <p>Conclusions</p> <p>A biofilm will benefit from using quorum sensing-induced EPS production if bacteria cells have the objective of acquiring a thick, protective layer of EPS, or if they wish to clog their environment with biomass as a means of securing nutrient supply and outcompeting other colonies in the channel, of their own or a different species.</p

Content based retrieval of 3D data and mpeg-7 metadata

Nowadays, 3D content based retrieval is an active research field. The evolution of 3D computer graphics accelarators and the progress of 3D digitization systems resulted an increase in the number of artefact’s digital replicas. It is a fact that 3D digitization is a common practice in the cultural heritage domain. The objective of this thesis is to investigate the application of 3D content based retrieval mechanisms in the area of pottery. Automating the procedure of matching vessel’s morphological features may lead to an important software tool that will enhance the research performed by archaeologists and ceramic researcher. To this end, a calibrated ground truth database with 3D vessels has been created. The database can be accessed though a prototype Web-based 3D content based retrieval search engine. The database contains both digitized and modeled vessels. Some of the modeled vessels have been produced by a random 3D vessel generator which has been developed within this thesis framework. A novel pose normalization algorithm applicable to 3D vessels algorithm is proposed. Novel 3D shape descriptors were derived by exploiting this pose normalization approach. These descriptors are specially designed for complete or nearly complete 3D vessels. They produce compact encodings of the vessels’ morphological features by taking under consideration their axial-symmetry. The performance evaluation results indicate that a specific method produces better results when compared to generic methods.Η ανάκτηση τρισδιάστατων αντικειμένων βάσει περιεχομένου αποτελεί σήμερα ένα ενεργό ερευνητικό πεδίο. Αυτό οφείλεται στη βελτίωση των επιταχυντών απεικόνισης τρισδιάστατων γραφικών πραγματικού χρόνου καθώς και στην αύξηση των τρισδιάστατων ψηφιακών αντιγράφων πραγματικών αντικειμένων. Σήμερα, τα συστήματα τρισδιάστατης ψηφιοποίησης βρίσκουν εφαρμογή σε ποικίλους επιστημονικούς τομείς. Ανάμεσα τους είναι και η επιστήμη της αρχαιολογίας όπου η τρισδιάστατη αποτύπωση αποτελεί κοινή πρακτική. Η παρούσα διδακτορική διατριβή επικεντρώνεται στην εφαρμογή των τεχνολογιών ανάκτησης βάσει περιεχομένου στο χώρο της κεραμικής. Εστιάζει στην αυτοματοποίηση της διαδικασίας εντοπισμού μορφολογικής συνάφειας ανάμεσα σε τρισδιάστατα ψηφιακά αντίγραφα αγγείων. Η συγκεκριμένη διαδικασία μπορεί να αποτελέσει ένα σημαντικό εργαλείο τόσο για τον αρχαιολόγο όσο και για τον μελετητή κεραμικών. Στο πλαίσιο της διατριβής αναπτύχθηκε μία βάση δεδομένων τρισδιάστατων αγγείων η οποία είναι προσβάσιμη διαμέσου ενός πρότυπου Διαδικτυακού συστήματος ανάκτησης βάσει περιεχομένου. Η συγκεκριμένη βάση δεδομένων περιλαμβάνει ψηφιοποιημένα αλλά και μοντελοποιημένα τρισδιάστατα αγγεία. Κάποια από αυτά έχουν προκύψει από μία γεννήτρια τυχαίων τρισδιάστατων αγγείων η οποία υλοποιήθηκε στα πλαίσια της διατριβής. Προτείνεται μια νέα μέθοδος κανονικοποίησης της κλίμακας, της θέσης και του προσανατολισμού ενός αγγείου από την οποία δύναται να προκύψουν περιγραφείς που ειδικεύονται στην κωδικοποίηση των μορφολογικών χαρακτηριστικών που φέρουν τα αγγεία. Οι περιγραφείς εκμεταλλεύονται την αξονική συμμετρία των αγγείων οδηγώντας σε συνεπτυγμένες κωδικοποιήσεις των μορφολογικών χαρακτηριστικών του βασικού σώματος και των προσαρτημάτων τους. Μέσα από μία σειρά πειραμάτων αποτίμησης της απόδοσης των προτεινόμενων περιγραφέων επαληθεύεται πως η ανάπτυξη μεθόδων περιγραφής που ειδικεύονται σε κάποια κατηγορία αντικειμένων, οδηγεί στη βελτίωση της διακριτικής ικανότητας ενός συστήματος ανάκτησης βάσει περιεχομένου