Towards Flexibility and Accuracy in Space DTN Communications

ABSTRACT Although Interplanetary Telecommunications rely on preconfigured contact schedules to make routing decisions, there is a lack of appropriate mechanisms to notify the network about contact plan changes. In order to fill this gap, we propose and evaluate a framework for disseminating information about queueing delays and link disruptions. In this context, we present such a mechanism, focusing not only on its functional properties, but rather on its impact objectives: to improve accuracy and routing performance. Supportively, we couple this mechanism with a DTN-compatible protocol, namely Contact Plan Update Protocol (CPUP), which implements our dissemination policy. Through simulation of space scenarios we show that accuracy can be significantly improved in all cases while routing performance can achieve a wide range, from minor through to significant gains, conditionally

Angiogenesis and apoptosis in testicular germ cell tumors

Aim: The measurement of growth factors in the serum of patients with testicular cancer and healthy controls and the comparison between these values, as well as the comparison between the three consecutive values of these variables in patients. We chose to study factors from pathways with proven role in carcinogenesis and to evaluate these factors for their potential prognostic or predictive role in patients with testicular cancer. Patients and Methods: 50 patients with histologically confirmed testicular germ cell tumor, after orchiectomy and before commencing chemotherapy and 16 healthy male controls were included in the study. Three blood samples were drawn, the first before the beginning of chemotherapy, the second one month after the completion of the second cycle of chemotherapy and the third one year after the completion of treatment. One blood sample was drawn from healthy controls. We measured and calculated in the serum samples of patients and healthy controls the following factors: a) Insulin like Growth Factor 1 (IGF-1) b) Insulin like Growth Factor Binding Protein 3 (IGFBP-3) c) IGF-1/IGFBP-3 molar ratio d) Matrix Metalloproteinase 2 (MMP-2) e) Matrix Metalloproteinase 9 (MMP-9) f) Tissue Inhibitor of Metalloproteinase 2 (TIMP-2) g) MMP-2/TIMP-2 ratio h) MMP-2/TIMP-2 ratio i) Vascular Endothelial Growth Factor A (VEGF-A) j) basic Fibroblast Growth Factor (bFGF) k) Platelet Derived Growth Factor BB (PDGF-BB) Results-Conclusions: Serum levels of the factors IGF-1, IGFBP-3, IGF-1/IGFBP-3 molar ratio, TIMP-2, MMP-2/TIMP-2 ratio, MMP-9/TIMP-2 ratio and PDGF-BB were initially abnormal in patients and normalized gradually, rendering these factors potentially useful as predictive factors of response to chemotherapy. Also, Ang-2 was initially lower in the good prognostic patient group and bFGF was initially lower in the patients with favorable outcome, something that could potentially be used as prognostic factor. The values of IGF-1/IGFBP-3 molar ratio, TIMP-2, MMP-2/TIMP-2 ratio, MMP-9/TIMP-2 ratio, showed initially statistically significant difference between patients and controls with early or late normalization, making these factors potentially useful for the follow up of the patients. Finally, Ang-2 values were higher in patients than normal controls and have not normalized, even one year after the completion of chemotherapy, making appealing the idea of correlating these high values with the long term increased cardiovascular morbidity of testicular cancers survivors, considering the role of angiopoietin pathway in tissue ischemia. This hypothesis merits further evaluation.Σκοπός: Η μέτρηση αυξητικών παραγόντων στον ορό ασθενών με καρκίνο όρχεως και μαρτύρων και η σύγκριση μεταξύ τους, καθώς και η παρατήρηση της διαχρονικής εξέλιξης των τιμών τους στους ασθενείς. Επιλέχτηκαν παράγοντες από μονοπάτια για τα οποία υπάρχει σαφής συσχέτιση με την αγγειογένεση και την απόπτωση. Υλικό-Μέθοδοι: Στη μελέτη εντάχθησαν 50 ασθενείς με ιστολογικά τεκμηριωμένο καρκίνο του όρχεως, αφού είχαν υποβληθεί σε ορχεκτομή και πριν την έναρξη της χημειοθεραπείας, καθώς επίσης και 16 φυσιολογικοί άρρενες μάρτυρες. Από τους μάρτυρες λήφθηκε ένα δείγμα αίματος και από τους ασθενείς τρία διαδοχικά δείγματα αίματος, το πρώτο πριν την έναρξη της χημειοθεραπείας, το δεύτερο ένα μήνα μετά την ολοκλήρωση του δεύτερου κύκλου της χημειοθεραπείας και το τρίτο ένα έτος μετά την ολοκλήρωση της χημειοθεραπείας. Μελετήθηκαν και υπολογίστηκαν στον ορό ασθενών και μαρτύρων τα επίπεδα των παραμέτρων: α) Insulin like Growth Factor 1 (IGF-1) β) Insulin like Growth Factor Binding Protein 3 (IGFBP-3) γ) Μοριακός λόγος IGF-1/IGFBP-3 δ) Matrix Metalloproteinase 2 (MMP-2) ε) Matrix Metalloproteinase 9 (MMP-9) στ) Tissue Inhibitor of Metalloproteinase 2 (TIMP-2) ζ) Λόγος MMP-2/TIMP-2 η) Λόγος MMP-2/TIMP-2 θ) Vascular Endothelial Growth Factor A (VEGF-A) ι) basic Fibroblast Growth Factor (bFGF) ια) Platelet Derived Growth Factor BB (PDGF-BB) ιβ) Angiopoietin 2 (Ang-2). Αποτελέσματα-Συμπεράσματα: Οι παράμετροι IGF-1, IGFBP-3, ο μοριακός λόγος IGF-1/IGFBP-3, ο TIMP-2, ο λόγος MMP-2/TIMP-2, ο λόγος MMP-9/TIMP-2 και ο PDGF-BB παρουσιάζουν αρχικά παθολογικές τιμές στους ασθενείς και ομαλοποιούνται σταδιακά, καθιστώντας τους πιθανότατα χρησίμους προβλεπτικούς παράγοντες ως προς την απάντηση στην χημειοθεραπεία. Επίσης, η Ang-2 και ο bFGF παρουσιάζουν αρχικά χαμηλότερα επίπεδα σε ασθενείς καλής πρόγνωσης και ευνοϊκής έκβασης αντίστοιχα, κάτι που θα μπορούσε επίσης να χρησιμοποιηθεί ως προβλεπτικός παράγοντας. Ο μοριακός λόγος IGF-1/IGFBP-3, ο TIMP-2, ο λόγος MMP-2/TIMP-2, και ο λόγος MMP-9/TIMP-2 παρουσιάζουν στατιστικά σημαντική διαφορά μεταξύ ασθενών και μαρτύρων με πρώιμη ή όψιμη αποκατάσταση στο φυσιολογικό και θα μπορούσαν πιθανότατα να χρησιμοποιηθούν στην παρακολούθηση των ασθενών. Τέλος, η Ang-2 είναι αυξημένη στους ασθενείς σε σχέση με τους μάρτυρες και δεν αποκαθίσταται στο φυσιολογικό, κάτι που θα μπορούσε να συσχετιστεί με την μακροχρόνια αυξημένη καρδιαγγειακή νοσηρότητα των ασθενών με καρκίνο του όρχεως, δεδομένου του ρόλου του μονοπατιού των αγγειοποιητινών στην ισχαιμία. Αυτή η υπόθεση χρήζει περαιτέρω έρευνας

Automated issue assignment using topic modelling on Jira issue tracking data

Abstract As more and more software teams use online issue tracking systems to collaborate on software projects, the accurate assignment of new issues to the most suitable contributors may have significant impact on the success of the project. As a result, several research efforts have been directed towards automating this process to save considerable time and effort. However, most approaches focus mainly on software bugs and employ models that do not sufficiently take into account the semantics and the non‐textual metadata of issues and/or produce models that may require manual tuning. A methodology that extracts both textual and non‐textual features from different types of issues is designed, providing a Jira dataset that involves not only bugs but also new features, issues related to documentation, patches, etc. Moreover, the semantics of issue text are effectively captured by employing a topic modelling technique that is optimised using the assignment result. Finally, this methodology aggregates probabilities from a set of individual models to provide the final assignment. Upon evaluating this approach in an automated issue assignment setting using a dataset of Jira issues, the authors conclude that it can be effective for automated issue assignment

Optimization of the DRASTIC method for the groundwater aquifers vulnerability assessment in the Region of Mesogaia Attica (en)

Εθνικό Μετσόβιο Πολυτεχνείο--Μεταπτυχιακή Εργασία. Διεπιστημονικό-Διατμηματικό Πρόγραμμα Μεταπτυχιακών Σπουδών (Δ.Π.Μ.Σ.) “Επιστήμη και Τεχνολογία Υδατικών Πόρων

Band Gap Measurements of Nano-Meter Sized Rutile Thin Films

Thin Titanium films were fabricated on quartz substrates by radio frequency magnetron sputtering under high vacuum. Subsequent annealing at temperatures of 600 ∘C in air resulted in single-phase TiO2 with the structure of rutile, as X-ray diffraction experiment demonstrates. Atomic-force microscopy images verify the high crystalline quality and allow us to determine the grain size even for ultrathin TiO2 films. Rutile has a direct energy band gap at about 3.0–3.2 eV; however, the transitions between the valence and conduction band are dipole forbidden. Just a few meV above that, there is an indirect band gap. The first intense absorption peak appears at about 4 eV. Tauc plots for the position of the indirect band gap show a “blue shift” with decreasing film thickness. Moreover, we find a similar shift for the position of the first absorbance peak studied by the derivative method. The results indicate the presence of quantum confinement effects. This conclusion is supported by theoretical calculations based on a combination of the effective mass theory and the Hartree Fock approximation