Affine multi-view modelling for close range object measurement

In photogrammetry, sensor modelling with 3D point estimation is a fundamental topic of research. Perspective frame cameras offer the mathematical basis for close range modelling approaches. The norm is to employ robust bundle adjustments for simultaneous parameter estimation and 3D object measurement. In 2D to 3D modelling strategies image resolution, scale, sampling and geometric distortion are prior factors. Non-conventional image geometries that implement uncalibrated cameras are established in computer vision approaches; these aim for fast solutions at the expense of precision. The projective camera is defined in homogeneous terms and linear algorithms are employed. An attractive sensor model disembodied from projective distortions is the affine. Affine modelling has been studied in the contexts of geometry recovery, feature detection and texturing in vision, however multi-view approaches for precise object measurement are not yet widely available. This project investigates affine multi-view modelling from a photogrammetric standpoint. A new affine bundle adjustment system has been developed for point-based data observed in close range image networks. The system allows calibration, orientation and 3D point estimation. It is processed as a least squares solution with high redundancy providing statistical analysis. Starting values are recovered from a combination of implicit perspective and explicit affine approaches. System development focuses on retrieval of orientation parameters, 3D point coordinates and internal calibration with definition of system datum, sensor scale and radial lens distortion. Algorithm development is supported with method description by simulation. Initialization and implementation are evaluated with the statistical indicators, algorithm convergence and correlation of parameters. Object space is assessed with evaluation of the 3D point correlation coefficients and error ellipsoids. Sensor scale is checked with comparison of camera systems utilizing quality and accuracy metrics. For independent method evaluation, testing is implemented over a perspective bundle adjustment tool with similar indicators. Test datasets are initialized from precise reference image networks. Real affine image networks are acquired with an optical system (~1M pixel CCD cameras with 0.16x telecentric lens). Analysis of tests ascertains that the affine method results in an RMS image misclosure at a sub-pixel level and precisions of a few tenths of microns in object space

Research of the Cenophytic Palaeoflora of the Eastern Mediterranean (Lesbos, Lemnos, Alonissos, Gavdos Islands)

Η ύπαρξη φυτικών (μακρο)απολιθωμάτων στον ελλαδικό χώρο είναι γνωστή από την αρχαιότητα και χαίρει ιδιαίτερης σπουδαιότητας από την ελληνική και παγκόσμια επιστημονική κοινότητα λόγω της ηλικίας, της ποικιλότητας ειδών και οργάνων και των πληροφοριών για το παλαιοπεριβάλλον και το παλαιοκλίμα. Μέσα από την παρούσα εργασία πραγματοποιείται: έρευνα νέων θέσεων εύρεσης φυτικών απολιθωμάτων Καινοφυτικής ηλικίας στην Ανατολική Μεσόγειο (νήσος Λέσβος, Λήμνος, Αλόννησος, Γαύδος), προσπάθεια προσέγγισης των νέων ευρημάτων από τη σκοπιά της παλαιοβοτανικής ανάλυσης με ό,τι αυτή περιλαμβάνει (ανατομία απολιθωμένου ξύλου με χρήση μικροσκοπίου, μελέτη αποτυπωμάτων φύλλων) αλλά και χρήση παλαιότερων (μέθοδος του Πλησιέστερου Σημερινού Συγγενή) και νέων μεθοδολογιών (π.χ. CLAMP, IPR) με στόχο την εξαγωγή σημαντικών συμπερασμάτων για τη γεωλογική ιστορία της Ανατολικής Μεσογείου και γενικότερα του ελλαδικού χώρου.The presence of plant (macro) fossils in Greece is known since ancient times and is of high significance by the Greek and International scientific community because of: their age, the species and plant organs diversity and the information about the palaeoenvironment and paleoclimate which can be excluded. The present work is dealing with: the research for new plant fossiliferous localities of Cenophytic age at the Eastern Mediterranean (Lesbos, Lemnos, Alonissos, Gavdos Islands), the study of the new findings under the perspective of palaeobotanical analysis (petrified wood anatomy with the usage of microscope, study of leaves imprints) and use of older (method of the Nearest Living Relative) and new methodologies (e.g., CLAMP, IPR) in order to export significant conclusions about the geological history of the Eastern Mediterranean and of Greece

Decision-making processes of weaning from mechanical ventilation: a comparative ethnographic insight into the dynamics of the decision-making environment

Many critical clinical conditions result in respiratory failure and precipitate the use of mechanical ventilation for their management. A prolonged period of mechanical ventilation is costly for both the patient, in terms of adverse effects, and the health care service. Therefore, immediate liberation of the patient from mechanical ventilation and constitution of spontaneous breathing, a process called weaning, is vital. This daily lifesaving practice, on which nurses are taking an increasing role with the introduction of nurse-led protocols, can become complicated requiring the effective use of assessment information through decision-making processes to improve outcomes of care. Most literature on the field fails to address that weaning decisions are affected not only by the nature of the task but also by the characteristics of the decision-maker and the decision environment. This research aimed to study nurses' decision-making processes when managing the weaning of long-term ventilated patients and to explore the impact of the diverse elements of the clinical environment on this intricate practice. An ethnographic approach was used to compare weaning decision-making processes in two different culturally intensive care units (ICU). Participant observation was used to follow the weaning practices of 10 patients in a Scottish ICU and 9 patients in a Greek ICU admitted with respiratory failure due to pneumonia or COPD exacerbation. Nurses were observed in their daily weaning practice and participated in reflective interviews at the end of their shift to extrapolate how they used the information to make their decisions. Semi-structured interviews were, then, conducted with nurses, physiotherapists and medical staff to explore their perceptions on weaning practices and the factors that influenced their decisions and clinical practice. Data were analysed thematically and concept maps were developed from the reflective interviews to analyse nurses‟ decision-making processes. The concept attainment theory was used as a framework to understand nurses' thinking processes. Nurses in all ranges of experience demonstrated a similar decision-making skill, which signifies that this cognitive process is not always related to the level of experience and knowledge. Nurses' weaning care was organised around maintaining a balance of care under the 'wean as able' medical instruction. Inconsistency in the weaning decisions led to a variability of weaning approaches followed for each patient and to long periods of weaning inactivity. Various reasons, related to the working relationships, lack of nurses‟ accountability, lack of support and unstructured information flow, were responsible for the deficiency in sustainable and consistent weaning decisions. In both settings, there was lack of culture to foster a shared decision-making approach in weaning practice and encourage nurses' autonomy in decision-making. This study concluded with proposing a collaborative decision-making framework for weaning long-term ventilated patients, which will involve and appreciate the contribution of all members of the multidisciplinary team

Diasporic and transnational identities in selected short stories of Greek Australian writers 1901- 2001

This thesis examines the notions of Greek identity in Australia through the analysis of selected short stories written in the Greek language by Greek Australian writers. Moreover, it focuses on the evolution of Greek identity in the diaspora and specifically in Australia during the twentieth century, whilst taking into consideration the recent phenomenon of transnationalism. The short story has been considered in the present study as the most representative and suitable type of genre to examine the concept of identity. As such, it is through the short story that different themes are explored, revealing aspects of Greek community-life in Australia, with an emphasis on identity issues and dilemmas. Attention is drawn to the empowering presence of a wide range of symbols and indicators, revealing an identity which is rich and complex in socio-cultural, historical and linguistic characteristics, relating to the Greek immigrant experience in the diaspora. The thesis concludes that there has been a shift from the original rigid migrant identity of the early twentieth century to a more flexible, tolerant, adapted and globally oriented identity