Shallow Water Bathymetry Mapping from UAV Imagery based on Machine Learning

The determination of accurate bathymetric information is a key element for near offshore activities, hydrological studies such as coastal engineering applications, sedimentary processes, hydrographic surveying as well as archaeological mapping and biological research. UAV imagery processed with Structure from Motion (SfM) and Multi View Stereo (MVS) techniques can provide a low-cost alternative to established shallow seabed mapping techniques offering as well the important visual information. Nevertheless, water refraction poses significant challenges on depth determination. Till now, this problem has been addressed through customized image-based refraction correction algorithms or by modifying the collinearity equation. In this paper, in order to overcome the water refraction errors, we employ machine learning tools that are able to learn the systematic underestimation of the estimated depths. In the proposed approach, based on known depth observations from bathymetric LiDAR surveys, an SVR model was developed able to estimate more accurately the real depths of point clouds derived from SfM-MVS procedures. Experimental results over two test sites along with the performed quantitative validation indicated the high potential of the developed approach.Comment: 8 pages, 9 figure

Μοριακή Δυναμική και Μεταβάσεις σε Υγρούς Κρυστάλλους

80 σ.Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Μικροσυστήματα και Νανοδιατάξεις”Στην παρούσα μεταπτυχιακή εργασία εξετάζεται η μοριακή δυναμική και οι μεταβάσεις δύο υλικώντης οικογένειας των καλαμιτίκών υγρών κρυστάλλων , το4-pentyl-4΄-cyanobiphenyl (5CB) και το 4-(2΄-methylbutyl)-phenyl-4΄-n-octylbiphenyl-4-carboxylate(CE8).Τα συστήματα αυτά μελετώνται στην καθαρή τους μορφή αλλά και παρουσία σωματιδίων ή φύλλων πολυιμιδίου(PI) με κύριο στόχο την αξιολόγηση των πειραματικών τεχνικών της Διηλεκτρικής Φασματοσκοπίας στην καταγραφή των μηχανισμών αποκατάστασης αλλά και των μεσοφάσεων για αυτή την κατηγορία υλικών. Αναλυτικότερα, με την Διηλεκτρική Φασματοσκοπία Εναλλασσομένου Πεδίου (DRS) για το καθαρό υλικό 5CBτο οποίο μελετήθηκε στο θερμοκρασιακό εύρος -150°Cέως 60°C και στο παράθυρο συχνοτήτων 10-10^6 Hz παρατηρήθηκαν τρεις μηχανισμοί. Οι δύο από αυτούς (α,δ) σχετίζονται με την περιστροφή του μορίου γύρω από τον εγκάρσιο άξονα του μορίου καιτον διαμήκη άξονα σύμφωνα με την υπάρχουσα βιβλιογραφία, ενώ ο τρίτος (δευτερεύον) μηχανισμός (β’) δεν έχει παρατηρηθεί στο παρελθόν.Παρουσία σωματιδίων χρυσού, διατηρείται η κινητικότητα των μηχανισμών, με τους α και δ να επιβραδύνονται ενώ ο β΄ να γίνεται πιο γρήγορος αλλά και με μικρότερη ενέργεια ενεργοποίησης. Αντιθέτως, τοποθετώντας το 5CB μεταξύ φύλλων PIαλλάζει δραματικά η κινητικότητα, όπου λόγω φαινομένου αγκίστρωσης δεν παρατηρούνται οι παραπάνω μηχανισμοί, ενώ εμφανίζονται δυο καινούργιοι σε υψηλότερες θερμοκρασίες με συμπεριφοράArrhenius. Παράλληλα, διεξήχθη μελέτη του CE8 σε καθαρή μορφή στο θερμοκρασιακό εύρος 40 έως 150°C, όπου καταγράφηκαν4 μηχανισμοί, οι οποίοι λόγω της πολυπλοκότητας του μορίου δεν συσχετίστηκαν με κάποια μοριακή κινητικότητα. Περαιτέρω, εφαρμόστηκε η Τεχνική των Θερμορευμάτων Αποπόλωσης (TSDC) στο 5CB(-150 έως 60°C) και στο CE8 (40 έως 150°C) με σκοπό την καταγραφή των μεταβάσεων συγκριτικά με την Διαφορική Θερμιδομετρία Σάρωσης (DSC). Οι μεταβάσεις και στα δύο υλικά που καταγράφηκαν ήταν με την μορφή κορυφών ρεύματος ή “ώμων”και ήταν σε συμφωνία με τις τιμές της βιβλιογραφίας. Πιο συγκεκριμένα, στο 5CB μπορέσαμε να παρατηρήσουμε τον μηχανισμό α αλλά και κάθε μετάβαση του υλικού, ενώ στο CE8 δεν ήταν εφικτή η καταγραφή των μπλε φάσεων.Επίσης, μελετήθηκε και για τα δύο υλικά, παρουσία φύλλων PI, η επίδραση του φαινομένου της αγκίστρωσης στο ρεύμα αποπόλωσης αλλά και πώς μετατοπίζονται θερμοκρασιακά οι μεταβάσεις στο CE8,παρουσία νανοσωματιδίων CdSe. Τέλος, από το σύνολο των πειραμάτων αναδεικνύεται η διακριτική ικανότητα των διηλεκτρικών τεχνικών και ιδιαίτερα του TSDCστην καταγραφή μεταβάσεων υγρο-κρυσταλλικών υλικών, όπου, σε αντιπαραβολή με τα λίγα αποτελέσματα της βιβλιογραφίας, καθιστά αναγκαία την περαιτέρω διερεύνηση τους.In the present work are examined the molecular dynamics and transitions of two calamitic liquid crystals, the 4-pentyl-4-cyanobiphenyl (5CB) andthe 4 - (2-methylbutyl)-phenyl-4-n-octylbiphenyl-4-carboxylate (CE8) . These systems are studied in their pure form, but also with the presence of particles or sheets of polyimide (PI) with the ultimate purpose to assess the experimental techniques of Dielectric Spectroscopy in recording the relaxation mechanisms and the mesophases for this class of materials. Specifically, with the Dielectric Relaxation Spectroscopy (DRS) for the pure material 5CB, which was studied in the temperature range -150 ° Ceos 60 ° C and in the frequency range 10^1-10^6Hz were observed three mechanisms. Two of them (α, δ) associated with the rotation of the molecule about the transverse axis of the molecule and the longitudinal axis, according to the literature, and a third (secondary) mechanism (b)wich was not observed previously. The 5CB with gold particles, the same mechanismsare maintained, with α and δ showing lower mobility while b being faster and with lower activation energy. Conversely, placing the 5CB between sheets changes dramatically mobility, due to the phenomenon of anchoring the above mechanisms are not observed, while two new ones appear at higher temperatures,portraining Arrhenius behaviour. Meanwhile, a study was conducted of CE8 in pure form in the temperature range 40 έως 150 ° C, where 4 mechanisms were observed, which due to the complexity of the molecule were not associated with specific molecular mobility. Further, we used the technique of Thermally Stimulated Depolarization Currents (TSDC) in 5CB (-150 to 60 ° C) and CE8 (40 to 150 ° C) in order to record the transitions compared to the Differential Scanning Calorimetry (DSC). The transitions in both materials were recorded in the form of current peaks or "shoulders" and was in agreement with literature values. More specifically, 5CB able to observe a mechanism and each transition of the material, while at CE8 was not possible to record the blue phases. Also both materials were studied with the presence of sheet PI, the effect of the phenomenon of anchoring to the depolarizing current but also how temperature-shifted transitions in CE8, with the presence of nanoparticles CdSe. Finally, from the set of experiments highlights the resolution of dielectric techniques and especially TSDC at recording transitions in liquid-crystalline materials, which, in comparison with the few results in the literature, requires further investigation.Δημοσθένης Κ. Γεωργόπουλο

Current and emerging drugs for the treatment of inflammatory bowel disease

During the last decade a large number of biological agents against tumor necrosis factor-α (TNF-α), as well as many biochemical substances and molecules specifically for the medical treatment of patients with inflammatory bowel disease (IBD), have been developed. This enormous progress was a consequence of the significant advances in biotechnology along with the increased knowledge of the underlying pathophysiological mechanisms involved in the pathogenesis of IBD. However, conventional therapies remain the cornerstone of treatment for most patients. During recent years conventional and biologic IBD therapies have been optimized. Newer mesalazine formulations with a reduced pill size and only one dose per day demonstrate similar efficacy to older formulations. New corticosteroids retain the efficacy of older corticosteroids while exhibiting a higher safety profile. The role of antibiotics and probiotics has been further clarified. Significant progress in understanding thiopurine metabolism has improved the effective dose along with adjunctive therapies. Quite a large number of substances and therapies, including biologic agents other than TNF-α inhibitors, unfractionated or low-molecular-weight heparin, omega-3 polyunsaturated fatty acids, microbes and microbial products, leukocytapheresis, and other substances under investigation, could offer important benefits to our patients. In this paper we review the established and emerging therapeutic strategies in patients with Crohn’s disease and ulcerative colitis

Mathematical model of uptake and metabolism of arsenic(III) in human hepatocytes - Incorporation of cellular antioxidant response and threshold-dependent behavior

<p>Abstract</p> <p>Background</p> <p>Arsenic is an environmental pollutant, potent human toxicant, and oxidative stress agent with a multiplicity of health effects associated with both acute and chronic exposures. A semi-mechanistic cellular-level toxicokinetic (TK) model was developed in order to describe the uptake, biotransformation and clearance of arsenical species in human hepatocytes. Notable features of this model are the incorporation of arsenic-glutathione complex formation and a "switch-like" formulation to describe the antioxidant response of hepatocytes to arsenic exposure.</p> <p>Results</p> <p>The cellular-level TK model applies mass action kinetics in order to predict the concentrations of trivalent and pentavalent arsenicals in hepatocytes. The model simulates uptake of arsenite (iAs^III) via aquaporin isozymes 9 (AQP9s), glutathione (GSH) conjugation, methylation by arsenic methyltransferase (AS3MT), efflux through multidrug resistant proteins (MRPs) and the induced antioxidant response via thioredoxin reductase (TR) activity. The model was parameterized by optimization of model estimates for arsenite (iAs^III), monomethylated (MMA) and dimethylated (DMA) arsenicals concentrations with time-course experimental data in human hepatocytes for a time span of 48 hours, and dose-response data at 24 hours for a range of arsenite concentrations from 0.1 to 10 μM. Global sensitivity analysis of the model showed that at low doses the transport parameters had a dominant role, whereas at higher doses the biotransformation parameters were the most significant. A parametric comparison of the TK model with an analogous model developed for rat hepatocytes from the literature demonstrated that the biotransformation of arsenite (e.g. GSH conjugation) has a large role in explaining the variation in methylation between rats and humans.</p> <p>Conclusions</p> <p>The cellular-level TK model captures the temporal modes of arsenical accumulation in human hepatocytes. It highlighted the key biological processes that influence arsenic metabolism by explicitly modelling the metabolic network of GSH-adducts formation. The parametric comparison with the TK model developed for rats suggests that the variability in GSH conjugation could have an important role in inter-species variability of arsenical methylation. The TK model can be incorporated into larger-scale physiologically based toxicokinetic (PBTK) models of arsenic for improving the estimates of PBTK model parameters.</p

Evaluation of the effectiveness of HDR tone-mapping operators for photogrammetric applications

[EN] The ability of High Dynamic Range (HDR) imaging to capture the full range of lighting in a scene has meant that it is being increasingly used for Cultural Heritage (CH) applications. Photogrammetric techniques allow the semi-automatic production of 3D models from a sequence of images. Current photogrammetric methods are not always effective in reconstructing images under harsh lighting conditions, as significant geometric details may not have been captured accurately within under- and over-exposed regions of the image. HDR imaging offers the possibility to overcome this limitation, however the HDR images need to be tone mapped before they can be used within existing photogrammetric algorithms. In this paper we evaluate four different HDR tone-mapping operators (TMOs) that have been used to convert raw HDR images into a format suitable for state-of-the-art algorithms, and in particular keypoint detection techniques. The evaluation criteria used are the number of keypoints, the number of valid matches achieved and the repeatability rate. The comparison considers two local and two global TMOs. HDR data from four CH sites were used: Kaisariani Monastery (Greece), Asinou Church (Cyprus), Château des Baux (France) and Buonconsiglio Castle (Italy).We would like to thank Kurt Debattista, Timothy Bradley, Ratnajit Mukherjee, Diego Bellido Castañeda and TomBashford Rogers for their suggestions, help and encouragement. We would like to thank the hosting institutions: 3D Optical Metrology Group, FBK (Trento, Italy) and UMR 3495 MAP CNRS/MCC (Marseille, France), for their support during the data acquisition campaigns. This project has received funding from the European Union’s 7 th Framework Programme for research, technological development and demonstration under grant agreement No. 608013, titled “ITN-DCH: Initial Training Network for Digital Cultural Heritage: Projecting our Past to the Future”.Suma, R.; Stavropoulou, G.; Stathopoulou, EK.; Van Gool, L.; Georgopoulos, A.; Chalmers, A. (2016). Evaluation of the effectiveness of HDR tone-mapping operators for photogrammetric applications. Virtual Archaeology Review. 7(15):54-66. https://doi.org/10.4995/var.2016.6319SWORD546671

Mesoscale modeling of combined aerosol and photo-oxidant processes in the Eastern Mediterranean

International audienceParticulate matter and photo-oxidant processes in the Eastern Mediterranean have been studied using the UAM-AERO mesoscale air quality model in conjunction with the NILU-CTM regional model. Meteorological data were obtained from the RAMS prognostic meteorological model. The modeling domain includes the eastern Mediterranean area between the Greek mainland and the island of Crete. The modeling system is applied to study the atmospheric processes in three periods, i.e. 13?16 July 2000, 26?30 July 2000 and 7?14 January 2001. The spatial and temporal distributions of both gaseous and particulate matter pollutants have been extensively studied together with the identification of major emission sources in the area. The modeling results were compared with field data obtained in the same period. The objective of the current modeling work was mainly to apply the UAM-AERO mesoscale model in the eastern Mediterranean in order to assess the performed field campaigns and determine that the applied mesoscale model is fit for this purpose. Comparison of the modeling results with measured data was performed for a number of gaseous and aerosol species. The UAM-AERO model underestimates the PM10 measured concentrations during summer and winter campaigns. Discrepancies between modeled and measured data are attributed to unresolved particulate matter emissions. Particulate matter in the area is mainly composed by sulphate, sea salt and crustal materials, and with significant amounts of nitrate, ammonium and organics. During winter the particulate matter and oxidant concentrations were lower than the summer values

The Effects of Malignant Transformation on Susceptibility of Human Urothelial Cells to CD40-Mediated Apoptosis

Background: The tumor necrosis factor (TNF) superfamily of ligands and receptors mediates immune cell survival. Some members possess a death domain, a protein motif that functions to transmit apoptotic signals, whereas others, such as CD40, do not. CD40 is expressed by both normal and malignant epithelial cells. To investigate the functional significance of this expression, we studied the effects of ligation of CD40, Fas, and TNF receptors (TNFRs) on the proliferation and survival of normal and malignant human urothelial cells and urothelial cells with disabled p53 function. Methods: Normal and malignant human urothelial cells were cultured with soluble TNF family agonists (CD40 ligand [CD40L], TNF-α, anti-Fas antibody, or cocultured with mouse fibroblasts stably transfected with plasmids that caused the cells to constitutively express CD40L or CD32; cell proliferation was estimated by an [3H]thymidine incorporation assay, and apoptosis was determined by Annexin V staining and by a DNA fragmentation assay. Messenger RNA levels for CD40 and potential downstream effector molecules were quantified by polymerase chain reaction-based and ribonuclease protection assays, respectively, and nuclear factor (NF) κB nuclear translocation was detected by immunofluorescence. All statistical tests were two-sided. Results: Soluble trimeric CD40L inhibited the growth of normal and malignant urothelial cells but did not induce apoptosis. Cell surface-presented CD40L induced massive apoptosis in CD40-positive transitional cell carcinoma cells but not in normal urothelial cells. Normal cells underwent CD40L-mediated apoptosis only in the presence of other TNFR agonists. An agonistic anti-CD40 antibody presented on the surface of CD32-transfected fibroblasts also induced apoptosis in transitional cell carcinoma cells and in normal urothelial cells. Apoptotic responses of tumor (but not normal) cells to soluble agonists were enhanced by blocking protein synthesis. Karyotypically normal urothelial cells with disabled p53 function underwent apoptosis during coculture with CD40L-expressing fibroblasts alone but were not additionally sensitive to additional TNFR agonists. Conclusions: Susceptibility to CD40 ligation-induced apoptosis may be a novel mechanism for eliminating neoplastically transformed urothelial cells. Loss of CD40 expression may be an important adaptive mechanism for transitional cell carcinoma development and progressio

SHALLOW WATER BATHYMETRY MAPPING FROM UAV IMAGERY BASED ON MACHINE LEARNING

The determination of accurate bathymetric information is a key element for near offshore activities, hydrological studies such as coastal engineering applications, sedimentary processes, hydrographic surveying as well as archaeological mapping and biological research. UAV imagery processed with Structure from Motion (SfM) and Multi View Stereo (MVS) techniques can provide a low-cost alternative to established shallow seabed mapping techniques offering as well the important visual information. Nevertheless, water refraction poses significant challenges on depth determination. Till now, this problem has been addressed through customized image-based refraction correction algorithms or by modifying the collinearity equation. In this paper, in order to overcome the water refraction errors, we employ machine learning tools that are able to learn the systematic underestimation of the estimated depths. In the proposed approach, based on known depth observations from bathymetric LiDAR surveys, an SVR model was developed able to estimate more accurately the real depths of point clouds derived from SfM-MVS procedures. Experimental results over two test sites along with the performed quantitative validation indicated the high potential of the developed approach

Attentive Learning of Sequential Handwriting Movements: A Neural Network Model

Defense Advanced research Projects Agency and the Office of Naval Research (N00014-95-1-0409, N00014-92-J-1309); National Science Foundation (IRI-97-20333); National Institutes of Health (I-R29-DC02952-01)