bluuebunny/crossref_metadata_2025 huggingface dataset:
Digital media in Greece
Authors: Φέρρα Ιωάννα
Published: May 2023

Αυτή η έρευνα εξετάζει την επιρροή των ψηφιακών μέσων στην επίμαχη πολιτική περίοδο της κρίσης στην Ελλάδα, καθώς και τον αντίκτυπο της πολιτικοοικονομικής σφαίρας στη διαμόρφωση του χώρου των ψηφιακών μέσων. Η μελέτη επικεντρώθηκε στην παράλληλη εξέλιξη της κρίσης (χρέους) και των ψηφιακών επικοινωνιών στην Ελλάδα, εστιάζοντας σε τέσσερις διαφορετικές ψηφιακές πλατφόρμες μέσων και καλύπτει μια περίοδο επτά ετών (2008, 2011-12, 2015). Η έρευνα χρησιμοποίησε τη θεωρία της κυβερνοσύγκρουσης (Cyberconflict) για να τοποθετήσει τις διαδικτυακές διαμεσολαβούμενες συγκρούσεις (κοινωνικοπολιτική και εθνοθρησκευτική κυβερνοσύγκρουση) σε ένα γεωκοινωνικό και ιστορικό πλαίσιο, υποδεικνύοντας τη δυναμική σχέση μεταξύ των διαδικτυακών μέσων και του εκτός διαδικτυου κόσμου. Αυτή η έρευνα προτείνει τη χρήση διαδικτυακών δεδομένων για την εξέταση της κυβερνοσύγκρουσης και ενημερώνει αυτό το θεωρητικό πλαίσιο, ώστε να υποστηρίξει αποτελεσματικά τη μελέτη των πλατφορμών μέσων κοινωνικής δικτύωσης. Η έρευνα αντανακλά την εξέλιξη των κοινωνικοπολιτικών συζητήσεων και τους πολιτικούς μετασχηματισμούς που προέκυψαν στο πλαίσιο της ελληνικής κρίσης (συζήτηση κατά/προς λιτότητας, συζήτηση ευρώ εναντίον δραχμής/ή grexit, αντι-/φιλοκυβερνητική συζήτηση και αντι-/φιλοευρωπαϊκός λόγος). Όπως προκύπτει από την ανάλυση, η προ κρίσης εποχή και ο διαδικτυακός λόγος, είχαν ήδη υποδείξει τα ζητήματα, τα οποία αργότερα διαμόρφωσαν τον λόγο της κρίσης online και offline. Στη συνέχεια, το δίκτυο του ΣΥΡΙΖΑ αφομοιώνει το κύμα κινητοποίησης των Αγανακτισμένων, προσφέροντας μια ευρύτερη πλατφόρμα και μια πολλά υποσχόμενη εκπροσώπηση όλων των συμμετεχόντων. Η πόλωση βοήθησε στο σχηματισμό λιγότερο ρευστών ταυτοτήτων online και offline, οι οποίες αναπτύχθηκαν περαιτέρω εστιάζοντας στη διαίρεση μεταξύ των πολιτικών Εμείς και Αυτοί. Στο πλαίσιο της κρίσης, το διαδίκτυο χρησιμοποιήθηκε ως μεγεθυντικός φακός, επισημαίνοντας τη σύγκρουση, την αντίθεση και υποστηρίζοντας την πόλωση. Η έρευνα καταλήγει στο συμπέρασμα ότι, πράγματι, η χρήση των ψηφιακών μέσων υποστήριξε την ανάπτυξη συλλογικής δράσης και εναλλακτικών δομών κινητοποιήσεων, καθώς και πολιτικού λόγου, αμφισβητώντας τόσο τα κυρίαρχα μέσα όσο και τις παραδοσιακές πολιτικές δομές. Ωστόσο, ο διαδικτυακός λόγος των μέσων ενημέρωσης δεν κατάφερε να κυριαρχήσει στη δημόσια σφαίρα, αλλά αντίθετα είχε ως αποτέλεσμα τον κατακερματισμό. Συνολικά, τα διαδικτυακά μέσα αναπαρήγαγαν την ήδη υπάρχουσα πόλωση και τις ιστορικές συνέχειες και περιορισμούς.
Perceptual models for sound analysis and synthesis
Authors: Ματτές Συμεών
Published: May 2023

Η διατριβή αυτή περιγράφει τη μεθοδολογία που ακολουθήθηκε για την υλοποίηση ενός βιολογικά εμπνευσμένου μοντέλου το οποίο έχει την ικανότητα να επεξεργάζεται ένα ακουστικό σήμα ώστε να προβλέπει την ανθρώπινη αντίληψη για τη θέσης μιας στατικής ηχητική πηγής στον τρισδιάστατο χώρο. Η προστιθέμενη χρήση του μοντέλου είναι για την αξιολόγηση των ηχητικών συστημάτων. Στη διατριβή αυτή γίνεται προσπάθεια να αναπτυχθεί τόσο ένα θεωρητικό όσο και ένα μαθηματικό πλαίσιο το οποιο μπορεί να υιοθετηθεί ως γενικευμένη θεωρία για την ανάπτυξη βιολογικά εμπνευσμένων μοντέλων για τον εντοπισμό της θέσης μιας ηχητικής πηγής απο τον άνθρωπο. Το μοντέλο χρησιμοποιεί ένα συνδυασμό από μονο ωτικά (ως προς το κάθε αυτί ξεχωριστά) ή διωτικά (συνδυασμό και των δύο αυτιών) δεδομένα και εντός ενός ψυχοακουστικού πλαισίου προβλέπει τη θέση μιας πηγής ήχου δεδομένου ότι ήχος έχει φτάσει απευθείας στα αυτιά χωρίς παρεμβάσεις ή αλλοιώσεις του ηχητικού σήματος.Τέλος, αξιολογείται η αποτελεσματικότητα του μοντέλου μέσω της σύγκρισης του με τα πειραματικά αποτελέσματα ενός πραγματικού τεστ σε ανθρώπους οι οποίοι εντόπισαν την τοποθεσία της πραγματικής πηγής ήχου σε τρισδιάστατο χώρο υπό ανηχοηκές συνθήκες.
Mechanism design for resource allocation problems
Authors: Μπίρμπας Γεώργιος
Published: May 2023

Το επίκεντρο αυτής της διατριβής είναι η μελέτη προβλημάτων ανάθεσης αγαθών τόσο από την αλγοριθμική όσο και από την παίγνιο-θεωρητική πλευρά. Συγκεκριμένα, μας ενδιαφέρουν οι εξής δύο τομείς: 1) Η δίκαιη ανάθεση αδιαίρετων αγαθών, όπου ο στόχος είναι η παραγωγή αναθέσεων που ικανοποιούν ένα συγκεκριμένο κριτήριο δικαιοσύνης 2) Τα προβλήματα διαμοιρασμού κόστους πολλών αντικειμένων, όπου ο στόχος είναι η παραγωγή αναθέσεων και μεθόδων διαμοιρασμού κόστους, που επιτυγχάνουν το κριτήριο της κοινωνικής ωφέλειας, υπό τον περιορισμό της κάλυψης του κόστους.Και για τα δυο αυτά είδη προβλημάτων, παρέχουμε αλγορίθμους που επιτυγχάνουν βέλτιστους ή σχεδόν βέλτιστους προσεγγιστικούς παράγοντες ως προς τα κριτήρια που ανά περίπτωση μας ενδιαφέρουν, δίνοντας έτσι μια ολοκληρωμένη εικόνα του τι είναι δυνατό σε αυτά τα δυο πεδία.
Le drame et le mouvement impressionniste dans l΄ambiance moderniste du XIXème siècle
Authors: Παπαχρήστου Μαρία
Published: May 2023

Η μελέτη αποτελείται από δυο κεφάλαια τα οποία χωρίζονται αντίστοιχα σε πέντε ενότητες. Το πρώτο κεφάλαιο αναφέρεται στην έκρηξη των διαφόρων ιδεολογικών προκλήσεων κατά την διάρκεια του 19ου αιώνα εκκινώντας από το κοινωνικο-πολιτικό και ιδεολογικό πλαίσιο που καθόρισε την άνοδο της αστικής τάξης στην εξουσία ήδη από την επομένη της Γαλλικής Επανάστασης. Το κεφάλαιο αυτό διαπραγματεύεται και επιχειρεί να φωτίσει το χρονικό της ανάδειξης της θεμελιώδους έννοιας του ατόμου και του τρόπου με τον οποίο η νέα ταυτότητα του ενέπνευσε τα λογοτεχνικά και καλλιτεχνικά δρώμενα του 19ου αιώνα. Το δεύτερο κεφάλαιο εμβαθύνει στη μετάβαση από τη δημιουργία της νέας ιδεολογικής ταυτότητας του ατόμου στη γέννηση μιας νέας αισθητικής η οποία επεκτείνεται έως τις πρώτες δεκαετίες του 20ου αιώνα. Εστιάζει κυρίως στην περίοδο του δεύτερου μισού του 19ου αιώνα κατά την οποία εμφανίζεται το κίνημα του ιμπρεσιονισμού στη ζωγραφική και στη δραματουργία. Μελετάται η σχέση του ιμπρεσιονισμού και του συμβολισμού στους τομείς που αναφέρθηκαν, καθώς και το ρεύμα του συμβολισμού που οδηγεί τη φιλοσοφία του ιμπρεσιονισμού σε νέες αισθητικές εξερευνήσεις έως τις αρχές του 20ου αιώνα. Εστιάζει ιδιαίτερα στο θεατρικό έργο του Octave Mirbeau, ο οποίος θεωρήθηκε ως ο κατ’ εξοχήν εκπρόσωπος του ιμπρεσιονιστικού δράματος και στη σχέση του με το συμβολιστικό θέατρο του μεγάλου δραματουργού Maurice Maeterlinck στον οποίο απονεμήθηκε μάλιστα το βραβείο Νόμπελ Λογοτεχνίας για την προσφορά του στα γράμματα και τις τέχνες. H μελέτη αυτή εξετάζει επομένως την εξέλιξη από τις καινοτόμες τάσεις του 19ου αιώνα, έως τον 20ο αιώνα, η οποία στιγμάτισε την έννοια του ατόμου. Οι εκπρόσωποι των κινημάτων που αναφέρονται επελέγησαν με βάση ένα ιδιαίτερο χαρακτηριστικό τους: αφομοιώνουν τις καλλιτεχνικές και λογοτεχνικές τάσεις της εποχής τους και, ακόμη και μέσα από την διαφαινόμενη αντιπαράθεσή τους, στην πραγματικότητα, συνομιλούν και εγκαινιάζουν έναν ευρύτερο διάλογο πάνω στην υπόθεση μιας σύγχρονης αισθητικής αντίληψης στην τέχνη και τη λογοτεχνία, και ιδιαίτερα τη δραματουργία, που θα χαρακτηρίσει το τέλος του 19ου αιώνα και θα θέσει τα θεμέλια για τα εικαστικά και λογοτεχνικά ρεύματα των πρώτων δεκαετιών του 20ου αιώνα.
Deep learning for robotic visual perception
Authors: Παπαϊωαννίδης Χρήστος
Published: May 2023

Στην παρούσα διδακτορική διατριβή μελετήθηκαν μεθοδολογίες βαθιάς μάθησης για την ανάπτυξη αποδοτικών συστημάτων ρομποτικής όρασης, μεγαλύτερης ακρίβειας και ευρωστίας, τα οποία είναι κατάλληλα για ρομποτικές εφαρμογές. Αυτά τα συστήματα μπορούν να διευκολύνουν τα ρομπότ να αντιμετωπίζουν ένα ευρύ φάσμα προβλημάτων οπτικής ανάλυσης που είναι απαραίτητα για την αποτελεσματικότερη ερμηνεία του περιβάλλοντός τους, αυξάνοντας έτσι τον βαθμό αυτονομίας τους και την αξιοπιστία τους. Πιο συγκεκριμένα, η παρουσιαζόμενη έρευνα αφορά τα προβλήματα της εκτίμησης στάσης αντικειμένου, της δισδιάστατης εκτίμησης ανθρώπινης στάσης σώματος/σκελετού, της σημασιολογικής κατάτμησης εικόνας και της εκτίμησης βάθους. Οι κύριες συνεισφορές αυτής της διατριβής στο πρόβλημα της εκτίμησης στάσης αντικειμένου είναι δύο. Αρχικά, προτείνεται μια συνάρτηση κόστους με πολλαπλούς στόχους για την εκπαίδευση ενός γρήγορου συνελικτικού δικτύου (Convolutional Neural Network - CNN) ως εξαγωγέα χαρακτηριστικών εικόνας, η οποία βασίζεται στα μoναδιαία τετραδόνια και επιτρέπει στο συνελικτικό δίκτυο να εξάγει περιγραφείς τρισδιάστατης στάσης αντικειμένου από τους οποίους μπορούν να εκτιμηθούν με ακρίβεια οι πραγματικές τριδιάστατες στάσεις αντικειμένων. Δεύτερον, δεικνύεται ότι το πρόβλημα εκτίμησης τρισδιάστατης στάσης αντικειμένου μπορεί να λυθεί πιο εύκολα για συνθετικές εικόνες, παρά για φυσικές εικόνες. Επιπλέον, προτείνεται μια καινοτόμος μέθοδος εκτίμησης τρισδιάστατης στάσης αντικειμένου που αποτελείται από δύο στάδια και εκμεταλλεύεται αυτήν την ιδιότητα. Όσον αφορά το πρόβλημα εκτίμησης της δισδιάστατης ανθρώπινης στάσης σώματος/σκελετού από εικόνες, προτείνεται μια καινοτόμος αρχιτεκτονική συνελικτικού δικτύου, η οποία έχει ως στόχο την επίτευξη ισορροπίας μεταξύ της εκτίμησης δισδιάστατης ανθρώπινης στάσης σώματος/σκελετού με υψηλή ακρίβεια και της γρήγορης παραγωγής προβλέψεων. Τέλος, όσον αφορά τα προβλήματα της σημασιολογικής κατάτμησης εικόνας και της εκτίμησης βάθους, προτείνεται μια μέθοδος για τη βελτίωση της απόδοσης των συνελικτικών δικτύων μέσω του συνδυασμού διαφορετικών μεθοδολογιών μάθησης/εκπαίδευσης (επιβλεπόμενη και αντιπαραθετική μάθηση). Επιπροσθέτως, η προτεινόμενη μέθοδος αποτελεί μια γενική μέθοδο που μπορεί να χρησιμοποιηθεί για την βελτίωση της ακρίβειας των συνελικτικών δικτύων σε προβλήματα επιβλεπόμενης πυκνής πρόβλεψης σε εικόνες (όπου απαιτούνται εκτιμήσεις σε επίπεδο εικονοστοιχείου), απαιτώντας ελάχιστες μόνο τροποποιήσεις για την προσαρμογή της σε νέα προβλήματα πυκνής πρόβλεψης σε εικόνες.
Backstories and knowledge in Ovid's "Metamorphoses"
Authors: Λεβέντη Μαρία
Published: May 2023

Η παρούσα διατριβή εξετάζει τρεις περιπτώσεις ιστορίας-υποβάθρου στις Μεταμορφώσεις του Οβιδίου μέσω της χρονικότητας και της γνώσης. Βασίζεται στη σπουδαιότητα, για την οβιδιανή αφήγηση, τόσο της αισθητηριακής αντίληψης, της εστίασης και της νοητικής κατανόησης, όσο και της χρονικότητας και της παρελθοντικότητας, ή της συνεπούς τάσης ενός αφηγητή να στρέφει την αφήγηση προς το παρελθόν. Υποστηρίζεται ότι στις Μεταμορφώσεις η έννοια του χρόνου είναι πιο περίπλοκη από ένα δίπολο παρόντος-παρελθόντος. Συνεπώς εισάγεται η «ιστορία-υπόβαθρο», δηλαδή μία ιστορία που λαμβάνει χώρα δύο χρονικά επίπεδα πριν από την κύρια αφήγηση. Η σχέση ανάμεσα στα χρονικά επίπεδα ανασυντίθεται διαφορετικά από αναγνώστες και χαρακτήρες: η πληρότητα των πληροφοριών που προκύπτει από την ανάγνωση μπορεί να συγκριθεί με τις περιορισμένες πληροφορίες στη διάθεση των χαρακτήρων. Η σύνθεση της διατριβής ακολούθησε τα εξής βήματα. Αρχικά οριοθετήθηκε κάθε ομάδα ιστοριών με βάση την τριμερή χρονικότητά της. Έπειτα εξετάστηκαν οι τρόποι με τους οποίους η γνώση σχετικά με ένα επίπεδο (δεν) μεταβαίνει σε επόμενο επίπεδο, όπως και η ένταση ανάμεσα στις μεθόδους που χρησιμοποιούν οι χαρακτήρες για να επιτύχουν την πρόσβαση στο παρελθόν τους και την ανάγνωση, στην οποία οι αναγνώστες βασίζουν τη γνώση τους. Τα κεφάλαια ΙΙ και ΙΙΙ εστιάζουν σε δύο τέτοιες μεθόδους: ο «Διόνυσος» στην οπτική αντίληψη και η «Μικρή Αινειάδα» στη μετάδοση πληροφοριών. Στο πρώτο, οι κρίκοι στην αλυσίδα της οπτικής αντίληψης περιορίζουν τη γνώση των χαρακτήρων για παρελθόν και παρόν, ωστόσο υπάρχει ένας τρόπος συμφιλίωσης της γνώσης αυτής με τα δεδομένα της κύριας αφήγησης. Το δεύτερο κεφάλαιο ασχολείται με δύο κύκλους μετάδοσης προειδοποιητικών πληροφοριών: έναν ανεπιτυχή από το απώτερο παρελθόν στο παρελθόν και έναν επιτυχή από παρελθόν σε παρόν, που συμβάλλει στη διαμόρφωση του μέλλοντος. Ο περιθωριακός χαρακτήρας των αφηγητών ίσως αποτελεί σχόλιο του Οβιδίου για τη δική του περιθωριακή θέση στο έπος. Αντικείμενο του κεφαλαίου IV («Δήμητρα») είναι μία ομάδα ιστοριών που δεν γειτνιάζουν στο κείμενο: η γνώση για τη σύνδεση προσωποποιημένων θεοτήτων με την πείνα δεν μεταβαίνει μεταξύ επιπέδων. Επίσης ο Οβίδιος συστηματικά απομακρύνει τους χαρακτήρες από κάθε μορφή αντίληψης, ακόμα και εντός χρονικού επιπέδου‧ επομένως η διαφορά στη γνώση αναγνωστών-χαρακτήρων φτάνει στο αποκορύφωμά της. Η ομάδα ιστοριών συνεπώς αναδεικνύεται σημαντική, ως αφηγηματολογική μονάδα με θεματική συνοχή σε τρία χρονικά επίπεδα. Η συχνή άγνοια των χαρακτήρων τούς μετατρέπει σε επίδοξους αφηγητές, που εισάγουν την προοπτική μίας εναλλακτικής ιστορίας. Κάποτε η επανάληψη οδηγεί, όχι στην παραγωγή δύο ιστοριών από μία, αλλά στη σύζευξη δύο ιστοριών σε μία. Κάθε ομάδα εστιάζει σε ένα θεματικό ερώτημα, ή σε έναν τρόπο αντίληψης του κόσμου (όραση, μετάδοση πληροφοριών, αντίληψη για οντολογικές ταυτότητες). Παρέχεται επομένως μία διπλή μακροσκοπική ανάγνωση βασισμένη σε ομάδες ιστοριών: μία ανάγνωση τόσο χρονική (κάθε ομάδα διέπεται από τη δική της χρονικότητα) όσο και θεματική (όλες οι ομάδες θέτουν ένα ερώτημα σχετικά με τη γνώση).
The Effects of Dark Matter upon Neutron Stars’ Properties
Authors: Vikiaris Michael
Published: May 2023

The nature of Dark Matter remains elusive despite all of our efforts. This missing matter of the universe cannot be directly observed, but we can see its gravitational effects. Galaxies and Clusters of Galaxies are most likely to contain Dark Matter that is trapped to their Gravitational Field. This leads us to the natural conclusion that Compact Objects might contain Dark Matter too. Neutron Stars are the natural laboratories that we can test our theories and receive crucial observational data. Thus, many models of Dark Matter have been produced to check the existence of Dark Matter in those stars. Since we know for sure the varying parameters of Neutron Stars (Radii, Mass, Λ etc.), by inserting Dark Matter to our equations we can see the differences we obtain in the aforementioned parameters. In this study, we chose to work with the Dark Matter Halo model, where a Neutron Star’s gravitational field is able to trap Dark Matter, but the latter expands way beyond the star’s radius, creating a Dark Halo around the Neutron Star. By studying the various parameters of the Star, we can obtain crucial information about the whole structure and the nature of Dark Matter.
Development of a simple algorithm for pre-fragment formation in proton-nucleus spallation reactions
Authors: Nicolis Nikolaos George , Chatzikotelis Athanasios
Published: May 2023

A Monte-Carlo algorithm is developed and coded in FORTRAN to calculate the energy, mass and charge distribution of the pre-fragments produced in proton induced spallation. The algorithm is based on Glauber’s theory together with a reasonable assumption on the type of the promptly emitted nucleons. For the evaporation stage, correlated values of pre-fragment mass, charge and excitation energy were fed into a properly modified version of the code MCEF (Monte-Carlo Evaporation-Fission) written in Java. A good agreement is obtained with the experimental mass and charge distributions of residues observed in 56Fe+p spallation reactions at 300, 500 and 750 MeV/A
Chernobyl and Fukushima nuclear accidents: similarities and differences
Authors: Kalef Ezra John
Published: May 2023

During the almost seven decades of use of nuclear fission for electric energy production two major nuclear accidents took place, i.e., the 1986 Chernobyl accident and the 2011 Fukushima one. They were caused by reactor power-surge and loss-of-coolant, respectively. Both accidents occurred during hot power reactor shutdown and had identical root causes, i.e., poor safety culture and safety management in nuclear industry and state authorities. A brief comparison of the facility and the accident characteristics, disaster response methods, as well as of their health, social, economic, and political adverse effects is attempted. The radiological impact of the Chernobyl accident was much higher than that of the Fukushima one; however, a similar statement may not hold for the other types of impact.
Study of HPGe detector shielding for use in inelastic neutron scattering experiments at the n_TOF/CERN facility
Authors: Papanikolaou Dimitris
Published: May 2023

The study of inelastic scattering reactions is important both in basic research as it can provide an insight on nuclear structure and aid in the validation of theoretical models, as well as in the field of applications. The most frequently used method to determine the neutron induced inelastic scattering cross section is by recording the emitted gamma rays from the de-excitation of the target nucleus. In this direction, the high energy resolution of the HPGe detectors is instrumental. The experimental setup can be further improved by shielding the HPGe against the scattered neutrons. The purpose of this work is to investigate the contribution of such shieldings used in inelastic neutron scattering experiments at the n_TOF facility at CERN and to optimise the experimental set-up. In this study, GEANT4, a package for simulating the transport of radiation through matter, was used to study the effect of the various shielding materials and geometries for CANBERRA’s EGPC 25S/N 540 p-type coaxial prototype HPGe.
MCNP simulations for the n_TOF NEAR station
Authors: Kopanos Sotiris Alexandros
Published: May 2023

The NEAR station is the newest experimental area of the n_TOF facility at CERN, utilizing the spallation process to generate extremely high neutron flux within a broad energy spectrum. As part of the campaign for the determination of the neutron beam spectral features, numerous foils have been irradiated last year and the induced activities were measured implementing a HPGe detector.

Experimental data analysis of the irradiated foil’s gamma-ray spectra, yielded the saturated activities for each material that can be used to unfold the characteristics of the neutron flux through data deconvolution using the SAND-II code. Since this process is mostly mathematical and does not account for geometry, shielding and scattering effects, correction factors need to be defined and applied to the measured activities in order to produce a more robust and accurate result.

For this purpose Monte Carlo simulations using the MCNP code were performed to investigate the self-shielding of the foils and its effect on both the neutron flux and the gamma rays emitted. Also, a detailed simulation including the full geometry of the experimental setup was developed and used in order to investigate possible influence of the peripheral materials (cement, other foils, mylar as well as the aluminum sample holder and rails) to the total flux that reaches each individual foil through scattering of neutrons.
Study of the cross section biasing technique using GEANT4 and determination of the parasitic neutrons at N.C.S.R. “Demokritos”
Authors: Ziagkova Anastasia , Michael Axiotis  , Sotirios Chasapoglou  , Maria Diakaki  , Kalliopi Kaperoni  , Michael Kokkiris  , Anastasios Lagoyannis  , Veatriki Michalopoulou  , Roza Vlastou
Published: May 2023

A simulation code was developed using the GEANT4 [1] toolkit in order to determine the   behavior of the neutron production beams generated by proton induced reactions while applying the cross section biasing technique  [2]. As the application of the biasing technique can cause a change in the physical processes occurring during the simulation, the specific implemented technique was tested via control simulations to determine any deviations of the results from the  theoretically expected ones. Different materials, geometries and biasing factors were used in order to qualify and quantify the discrepancies between the unbiased and the biased simulations.

One of the main reactions used for the production of the neutron beam at the Tandem accelerator laboratory of N.C.S.R. “Demokritos” [3] is the  3H(p,n)3He one. In the geometry of the main tritiated target, elements such as molybdenum, copper and titanium are included. During the interaction of the proton beam with them, it is possible to produce neutrons that will “contaminate” the main neutron beam. These neutrons are called parasitic and their quantification is necessary in order to avoid obtaining erroneous results in cross section measurements on the various targets under study.[4] By constructing the  proper geometry and using the GEANT4 code mentioned above, the determination of the parasitic neutrons is achieved with optimal statistical results in short computational times, while the discrepancies between the unbiased and the biased results remain minimal.
Measurement of differential cross sections for proton elastic scattering on natO at Ep= 4-6 MeV, suitable for EBS
Authors: Kokkoris Michael , Bosbotinis Kostas , Foteinou Varvara , Lagoyannis Anastasios , Maragkos Fotis , Patronis Nikolaos , Taimpiri Evangelia , Ziagkova Anastasia
Published: May 2023

In this study we present the experimental differential cross sections of natO(p,p0) elastic scattering, determined via the relative measurement technique, in the proton beam energy range Elab=4-6 MeV with a varying step (from 5-15 keV), at six backscattering detector angles between 120o and 170o (every 10o). A thin, self-supporting target manufactured in the lab was used in this experiment and the determination of its stoichiometry was carried out according to the currently existing evaluation, which has also been benchmarked recently. The measurements were performed using the Van de Graaff Tandem 5.5 MV Accelerator of N.C.S.R. “Demokritos” in Athens, Greece. The differential cross-section datasets obtained in the present work and already existing ones in literature for this extended proton beam energy range are shown and the observed peculiarities and discrepancies are discussed and analyzed.
A New Objective Function for RPL Based on Combined Metrics in Mobile IoT
Authors: Echoukairi Hassan , Ouacha Ali , Oubaha Jawad , El Ghmary Mohamed
Published: May 2023

To satisfy the quality of service requirements for some applications in the Internet of Things (IoT) network with mobile nodes, routing protocols must be adaptable to make better routing decisions. Routing Protocol for Lowpower and Lossy Networks (RPL) is one of the routing protocols that support metrics and constraints while building a Destination Oriented Directed Acyclic Graphs (DODAG) using a specific Objective Function (OF). However, RPL metrics that use standard OFs do not guarantee the performance criteria for a specific mobile IoT in terms of received and lost packets, overhead, throughput and power consumption. In this paper, we propose a new version of mrhof based on a combination of metrics such as total energy, the number of neighbors, and expected transmission count (ETX) to evaluate RPL performances in a mobile context. Then, we compare the assessment of this function to existing OFs based on various mobility models (Random Waypoint (RWP), Reference Point Group Mobility (RPGM), Nomadic) and node densities. The results show that this new function is more efficient than the standards OF in terms of packets received and packets lost with Random Way Point and RPGM models. Regardless of the number of nodes, it also reduces ETX and traffic overhead for all mobility models, as well as convergence time in the Random Waypoint environment. Furthermore, this new function contributes to the improvement of Rtmetric, the enhancement of throughput at low density only in favor of RWP and RPGM models, and an effective power consumption reduction through all densities and mobility models.
The Evaluation of IEEE 802.11ah Performance Based on the Effect of Mobility, Node’s Number, and Traffic Using the Markov Chain Model
Authors: Ahmad Riza Tengku , Gunawan Dadang , S. Arifin Ajib
Published: May 2023

The Internet of Things (IoT) is currently growing rapidly and one of the technologies supporting it is wireless fidelity (Wi-Fi) standard IEEE 802.11ah. This technology supports mobility and has a large number of nodes or devices with small energy consumption; hence it is capable of functioning for a long time. In this study, three work scenarios were proposed, namely 1) the mobility, which involves changing the distance between the access point (AP) and the nodes, 2) changing the node’s number, and 3) testing the variations in traffic by changing the collision possibilities and the RAW (Restricted Access Window) (the full title). slot duration in order to analyze the IEEE 802.11ah network performance parameters. The results showed that there was a decrease in throughput, an increase in energy consumption, and a delay due to changes in the nodes’ number and movement/mobility. Also, the variation in traffic by changing the collision probability causes a change in throughput, hence when the collision probability is large, the throughput decreases, while the delay value increases, and vice versa. In conclusion, this study proved that changes in the nodes’ number, movement/mobility, and traffic collision probability affected the IEEE 802.11ah network's performance in throughput, delay, and energy consumption parameters.
Taming the Long Tail: The Gambler’s Fallacy in Intermittent Demand Management
Authors: Bi Sheng , He Long , Teo Chung Piaw
Published: May 2023

Problem definition: “Long tail” products with intermittent demand often tie up valuable warehouse space and capital investment for many companies. Furthermore, the paucity of demand data poses additional challenges for model estimation and performance evaluation. Traditional inventory solutions are not designed for products with intermittent demand. In this paper, we propose a new framework to optimize the choice of “replenishment timing” and “replenishment quantity” for managing the inventory metrics of long tail products, when evaluated over a finite horizon. Methodology/results: Our analysis is motivated by a recent interesting observation that the gambler’s fallacy phenomenon actually holds in a finite number of coin tosses. We use this phenomenon to analyze the inventory problem for intermittent demand to demonstrate that classical inventory models using KPIs such as fill rate, average cost per cycle, or average cost per unit, etc., must necessarily “bias” the underlying demand distribution to account for the finite horizon effect. We provide the exact closed-form expressions of the biased distribution to account for this effect in performance evaluation. The results show that the choice of replenishment timing and replenishment quantity is essential to superior performance on several key inventory metrics. Managerial implications: For long tail products, the belief that it is less likely for another demand to arrive shortly after a preceding one (the gambler’s fallacy), turns out to be true when performance is tabulated over a finite horizon, even if demands across time are independent. So it pays to delay the replenishment of depleted stocks to save on holding cost and warehouse space. Managers can optimize the replenishment timing, besides choosing the replenishment quantity, to optimize the performance metrics of several classes of inventory problems. This is especially useful for companies managing a large number of long tail products.

Funding: This work was supported in part by the National Natural Science Foundation of China [Grant 72192832] and the 2019 Academic Research Fund Tier 3 of the Ministry of Education-Singapore [Grant MOE-2019-T3-1-010].

Supplemental Material: The e-companion is available at https://doi.org/10.1287/msom.2023.1217 .
Joint Inventory and Scheduling Control in a Repair Facility
Authors: Özkan Erhun , van Houtum Geert-Jan
Published: May 2023

Operations Management in a Repair Facility

Capital goods are machines or products that are used in the production of goods or service deliveries. Maintenance service providers keep spare parts on stock so that, whenever a critical component of a capital good breaks down, the broken part is replaced with a spare part to prevent long and costly downtime. In “Joint Inventory and Scheduling Control in a Repair Facility,” Özkan and van Houtum study inventory and repair scheduling decisions of a maintenance service provider for repairable capital goods. In case of a stock-out, the service provider should decide whether to back-order the demand or execute an emergency repair, which is an urgent but expensive repair operation for a broken part. The authors derive a simple and intuitive decision rule stating if the emergency repairs are necessary to achieve a close-to-optimal system performance. Moreover, they propose a simple, intuitive, and easy-to-implement heuristic control policy that performs well in numerical experiments.
Technical Note—Optimal Procurement in Remanufacturing Systems with Uncertain Used-Item Condition
Authors: Nadar Emre , Akan Mustafa , Debo Laurens , Scheller-Wolf Alan
Published: May 2023

The Importance of Considering System Congestion When Acquiring Used Items for Remanufacturing

The condition of used items obtained by remanufacturers often varies widely and may only be truly known after an inspection. In “Technical Note–Optimal Procurement in Remanufacturing Systems with Uncertain Used-Item Condition,” Nadar, Akan, Debo, and Scheller-Wolf study the procurement problem by taking into account this pre-inspection uncertainty as well as the quantities of available used items of different quality levels. The authors provide a novel optimal policy structure for a Markov decision process representation of this problem. They prove that the optimal acquisition decision depends on the system congestion level — the total remanufacturing load weighted by the quality levels. Their results show that it becomes less desirable to acquire a used item as the number of available items or the quality level of any available item increases. To prove their results, the authors introduce a new functional characterization that is a relaxation of supermodularity and discrete convexity.
Spatial and Temporal Rainfall Analysis of the Bidi Tobacco Growing Areas of India.
Authors: Reddy D. Damodar , Rao Chandrasekhara , Prasad L. K. , Bindu J. Poorna , Kumari B. Krishna , Jayapradha T. Anuhya
Published: May 2023

The monsoon extremities, such as heavy rainfall, drought, and cyclones are becoming frequent across India and causing substantial damage to commercial crops. To predict/identify the trend in rainfall of Bidi tobacco growing areas were studied for variability, trend, and detection of any change in monthly rainfall over the years (1990-2020) using Mann-Kendall trend analysis and Sen’s slope tests. Monthly rainfall in three unique Bidi production zones has shown distinct trends. A positive trend was observed in March, April, August, September, November, and December while negative trends were in June and July months in Gujarat. During the crop growth period, the trend is positive except in October, the magnitude of change was negligible. However, supplemental irrigation is to be planned during water deficit periods of the nursery (June and July) and critical crop growth periods. In Karnataka, a positive trend from February to October was observed while a negative trend during November, December, and January. The magnitude was high in January (+) and September (-) and significant. The period of negative trend has coincided with the harvesting hence, the crop may not get affected. However, high rainfall during the crop growth period causes a detrimental effect. To mitigate the inundation proper drainage facility should be created through field channels to flush out excess water to avoid saturation at the root zone as this crop is especially extremely sensitive to poor aeration and anaerobic conditions. A positive trend was observed in January, February, March, June, August, and September months in Andhra Pradesh, whereas a negative trend was high in October & November which coincided with crop growth and might significantly affect Bidi tobacco. The positive trend in rainfall during June is high and the same can be utilized for nursery during July-August through proper moisture conservation measures.
Mastopexy: a means to correct breast ptosis
Authors: Ramadan Francesca
Published: May 2023

The demand for aesthetic procedures is at an all-time high, and nowhere is this more prevalent than in the practice of mammoplasties (i.e., procedures to modify shapes and sizes of breasts), particularly mastopexies (commonly known as breast-lift surgeries). This clinical article introduces different types of ptosis (i.e., breast sagging or uneveness) and maxtopexies, delving further into the relationship between them. The management of ptosis recurrence is also discussed.
Research Roundup
Authors: Mcgloin Claudia
Published: May 2023

In this regular feature, aesthetic nurse Claudia McGloin presents a brief synopsis of a range of recently published articles on medical aesthetics. Research roundup aims to provide an overview, rather than a detailed summary and critique, of the papers selected. Should you wish to look at any of the papers in more detail, a full reference is provided at the end of each study summary
Orthodontic-induced Temporary Sensory Nerve Deficit of the Lower Lip
Authors: Chung Matthew , Lord Timothy , Flannigan Norah
Published: May 2023

This article presents a case of temporary right-sided numbness of the lower lip during orthodontic treatment to upright an impacted lower right second molar (LR7) in a 15-year-old male. Following cone beam computed tomography (CBCT) this was revealed to be a result of deficient bone between the roots of LR7 and close intimacy to the mandibular canal. Traction to LR7 was discontinued and the patient's orthodontic treatment was completed uneventfully, with full recovery of normal sensation in the lower lip.

CPD/Clinical Relevance: Sensory nerve symptoms initiated by orthodontic treatment are rare, and the presentations, diagnostic tools, management and outcomes of these cases have been reviewed to devise and recommend an appropriate management plan for the treating clinician.
O PAPEL DA ASSESSORIA DE COMUNICAÇÃO NO NO CONTEXTO DA MIDIATIZAÇÃO
Authors: Teixeira Raphael Moroz , Fort Mônica Cristine
Published: May 2023

No contexto da midiatização – marcado pela conectividade e pela convergência –, a mediação entre as empresas e a sociedade não se dá apenas pelos meios de comunicação de massa tradicionais. Considerando isso, o objetivo deste artigo é discutir o papel da assessoria de comunicação nesse contexto. O método utilizado foi a pesquisa bibliográfica, tendo sido empregados pressupostos de autores como Andreas Hepp, Nick Couldry, Mark Deuze e Henry Jenkins. Conclui-se que a assessoria de comunicação tem se aproximado da esfera da comunicação mercadológica, dialogando com o marketing e a publicidade.
O SUJEITO-DA-CÂMERA EM FALSOS DOCUMENTÁRIOS
Authors: Souza Gustavo , Botelho Marina
Published: May 2023

Pretende-se refletir sobre as transformações dos sujeitos-da-câmera em falsos documentários de terror do tipo found footage, pensando a experiência do espectador de acordo com cada tipo de posicionamento de sujeito. Para isso, conceitualiza os tipos de sujeito-da-câmera (RAMOS, 2008) e analisa sequências de quatro filmes de found footage: [REC] (2007), Atividade Paranormal 2 (2011), Host (2020) e Murder Death Koreatown (2020). Compreende-se que os sujeitos-da-câmera se transformam em diálogo com o surgimento de novas mídias e suas linguagens e com o contexto social da época, em função de um ilusionismo que procura parecer real e verossímil.
SOBRE CINEMA, AMOR E CUIDADO: mulheres negras na direção e na curadoria
Authors: Ferreira Ceiça , Penha de Souza Edileuza
Published: May 2023

Este trabalho examina a proposta curatorial de três eventos realizados em 2017, que destacam a pluralidade da produção audiovisual empreendida por mulheres negras e a atuação destas no âmbito da curadoria. Também analisa representações de mulheres negras, suas experiências, relações de cuidado e vínculo familiar em três curtas. A hipótese levantada é a de que, em contraponto ao racismo e ao sexismo vigentes, as mulheres negras brasileiras têm elaborado narrativas que articulam memória, afeto e pertencimento; e práticas fílmicas, nas quais assumem a posição de protagonismo
MERCANTILIZAÇÃO DA CHECAGEM NAS AGÊNCIAS CHEQUEADO E LUPA NA AMÉRICA LATINA
Authors: Alencar Marta Thaís , Aquino Bittencourt Maria Clara
Published: May 2023

O presente artigo aborda as estratégias e os negócios das duas principais agências de fact-checking na América Latina: Lupa (Brasil) e Chequeado (Argentina). Partindo de um estudo comparativo das agências, o trabalho consiste em verificar a mercantilização da checagem para empresas de jornalismo e outras organizações.  Com base nos resultados, o artigo revela que o fact-checking na América Latina é um modelo de negócio adotado pelas iniciativas, que promove o empreendedorismo jornalístico e atua ao mesmo tempo, no combate à desinformação e na defesa pela democracia.
Ecology of horn snail (Telescopium telescopium, Linnaeus 1758) on mangrove ecosystem of Pantai Mayangan, West Java
Authors: RAHMAWATI GITA , YULIANDA FREDINAN , SAMOSIR AGUSTINUS M.
Published: May 2023

Abstract. Rahmawati G, Yulianda F, Samosir AM. 2013. Ecology of horn snail (Telescopium telescopium, Linnaeus 1758) on mangrove ecosystem of Pantai Mayangan, West Java. Bonorowo Wetlands 3: 41-49. The aim of this research was to know the influence of mangrove and abandoned ponds on the growth and population of horn snail (Telescopium telescopium, Linnaeus 1758) at Pantai Mayangan, Legon Kulon Subdistrict, Subang District, West Java. The study was conducted from May to October 2011 with monthly sampling intervals. Sampling was done in two places: abandoned pond (station 1) and mangrove area (station 2). Each station consists of 3 replications, using 1 x 1 m2 transects. Physical-chemical water parameters are measured in situ, whereas TDS, TSS, and COD are measured in the Laboratory of Productivity and Aquatic Environment, Bogor Agricultural University, Bogor. The bottom substrate was sampled in the first month and last month of the study and was analyzed at the Soil Science Routine Laboratory, Bogor Agricultural University, Bogor. The results showed that the density of horn snail population in mangrove areas was lower than in abandoned ponds. Based on Morisita’s index, the horn snail distribution pattern is uniform, random, and clumped. Horn snail has a negative allometric growth pattern with b <3, i.e., long growth is more dominant than weight growth. The condition factor of horn snails in abandoned ponds is higher than in mangrove areas. Physical-chemical water parameters generally support horn snail growth. The horn snail meat index indicates that the meat is lower than the shell weight. Horn snail can be managed by increasing the volume of pond water, recirculation system, use of pond or sedimentary channel to cope with low dissolved oxygen, mangrove planting to maintain ecosystem balance, and horn snail catching in abandoned pond area which has high horn snail density
Effect of cypermethrin insecticide on root chromosome morphometry of scallion (Allium fistulosum)
Authors: HAQ FESA AULIA NURUL , ETIKAWATI NITA , Solichatun Solichatun
Published: May 2023

Abstract. Haq FAN, Etikawati N, Solichatun. 2023. Effect of cypermethrin insecticide on root chromosome morphometry of scallion (Allium fistulosum). Cell Biol Dev 7: 14-21. Farmers in Tawangmangu, Karanganyar, Central Java, Indonesia, commonly use a pesticide known as cypermethrin insecticide whenever growing scallion (Allium fistulosum L.). If used at excessive levels, cypermethrin pesticide can be fatal to plants. Chromosome morphological changes are an indicator of cypermethrin insecticide's toxicity. Chromosomal morphometry, the study of chromosomal size and shape, can provide an overall picture of the quality of a plant's development. This research aimed to evaluate cypermethrin insecticide's impact on A. fistulosum root chromosomal morphometrics. Information gleaned from chromosomal morphometry includes chromosome shape, chromosome size, aberration type, chromosomal aberration index, relative asymmetry index, relative centromere index, and mitotic chromosome index. The concentration of cypermethrin was the sole independent variable in this study, which used a Completely Randomized Design (CRD) factorial arrangement. Long green onions were treated with varying concentrations of cypermethrin for up to four weeks: 0 mg/L, 0.05 mg/L, 0.10 mg/L, 0.15 mg/L, 0.20 mg/L, and 0.25 mg/L. The squash method was used to prepare the plant's apex roots. The root chromosomal visualization output was subjected to quantitative and qualitative descriptive analysis. The mitotic index decreased, and the chromosome aberration index increased after exposure to cypermethrin pesticides. The higher the concentration of the pesticide cypermethrin, the lower the mitotic index and the greater the chromosome aberration index. Long green onion root cells exposed to cypermethrin insecticide underwent chromosomal aberrations that could be identified qualitatively. Sticky chromosomes, chromosome bridge, chromosome agglutination, disrupted metaphase, disturbed anaphase, and hypoploid cell are examples of chromosomal aberrations.
Adaptation strategies of small-scale agriculture production to climate change impacts in Micheweni, Tanzania
Authors: BAKARI MUSSA SAID , ABDALLAH J.M. , HELLA J.P.
Published: May 2023

Abstract. Bakari MS, Abdallah JM, Hella JP. 2018. Adaptation strategies of small-scale agriculture production to climate change impacts in Micheweni, Tanzania. Trop Drylands 3: 60-75. The impacts of climate change in the form of prolonged drought, low rainfall, increasing temperature and sea level rise are predicted to affect developing nations especially in the dryland region such as in Africa. This study was conducted in three Shehias within Micheweni district, Pemba, Tanzania to assess the extent of climate change impacts and crop yields. Specifically, the study aimed to identify and assess climate change impacts to small scale farmers, assess the link between precipitation, temperature, sea-level rise, crop/fish production, identify and assess climate change adaptation strategies by small-scale farmers in the District. Primary data were obtained through focus group discussions, key informants, and households. Household questionnaires and checklists were used to collect both qualitative and quantitative data to obtain information from respondents. In each Shehia, a sample of 30 households was randomly selected from the register for household interviews. Climate data were obtained from Pemba Meteorological Headquater at Chake Chake Airport and the Matangatuani station. Secondary data were extracted from literature review. Data analysis was done using Excel (to get descriptive statistics), Statistical Package for Social Sciences (SPSS), correlation analysis and content analysis methods. The trend of climate measured for the last 30 years showed decreasing precipitation and increased temperatures. The highest annual average rainfall was 196.2 mm (1986) and the lowest 72.5 mm (2001) measured at the Matangatuani Meteorological station. Crop failure, low crop production, soil infertility, crop pests/diseases and seawater intrusion were major climate change impacts. Results indicated annual decrease in crop production in the past 10 years, with pests and diseases, uneven distributed low rainfall and extended drought periods. Crop rotation, use of improved seeds and new crop varieties, fertilizer application, irrigation, mixed cropping, and adjusting sowing dates were some of adaptation strategies. Seawater rise and intrusion constrained paddy farm production where fish and salt farming contributed to environmental degradation in farming areas. The decrease in crop production resulted mostly from climate variations; hence community should establish short-term and drought-resistant crops.
Optimization production model and financial feasibility analysis on planning of integrated lontar sugar industry in Rote Ndao District, East Nusa Province, Indonesia
Authors: Fahrizal Fahrizal , JASMAN JASMAN , NGGANDUNG YEHESKIAL , KARTIWAN KARTIWAN
Published: May 2023

Abstract. Fahrizal, Jasman, Nggadung Y, Kartiwan. 2020. Optimization production model and financial feasibility analysis on planning of integrated lontar sugar industry in Rote Ndao, East Nusa Tenggara, Indonesia. Trop Drylands 21: 25-30. In general, lontar (Borassus flabellifer) sugar consists of molded sugar and crystal sugar produced from lontar sap. Both types of sugar can be produced together in one business unit, but in fact, most home industries produce them partially. This research aimed to obtain an optimization of production model and financial feasibility of integrated lontar sugar industry. The linear programming optimization method was used to determine the optimal amount of molded and crystal lontar sugar production with the objective function of profit maximization. The model was validated on lontar sugar home industry in Rote Ndao District, East Nusa Tenggara Province, Indonesia. Scenario of price change and interest rates were used to measure the level of sensitivity of financial feasibility. The results showed that a maximum profit of IDR 186,741 was obtained by producing 47.25 kgs of molded sugar and 57.93 kgs of crystal sugar every day. The financial feasibility analysis of IRR, NPV, and BC indicators showed that the project was still feasible when the sugar price fall down by 10%, the price of lontar sap increased by 20%, and interest rates rose to the level of 24%.
Nutrient and anti-nutrient compositions of cowpea (Vigna unguiculata) and mung bean (Vigna radiata) seeds grown in humid Southeast Nigeria: A comparison
Authors: Enyiukwu David Nwazuo , Chukwu Lwanga Azubuike , BASSEY INEMESIT N.
Published: May 2023

Abstract. Enyiukwu DN, Chukwu LA, Bassey IN. 2020. Nutrient and anti-nutrient compositions of southern pea (Vigna unguiculata) and mung bean (Vigna radiata) seeds grown in humid Southeast Nigeria: A comparison. Trop Drylands 3: 41-45. Pulses are important components of African cuisines. Cowpeas (Vigna unguiculata (L.) Walp.) are commonly consumed in most parts of Nigeria, but mung bean (Vigna radiata (L.) Wilczek) though new in the agro-landscape, is gradually gaining popularity. Its popularity is based on the speculation that it is of higher nutritional content than cowpeas. This work evaluated the nutritional compositions of seeds of both pulse crops grown in humid southeast Nigeria using classical and spectrometric analysis. Results obtained from the study showed that the mean proximate compositions of mung bean (17.70%) did not statistically (P?0.05) differ from that recorded for cowpea seeds (17.30%). However, irrespective of the high magnesium content (62.39 mg g-1) of mung bean, the mean mineral nutrients in cowpea (270.69 mg g-1) is grossly higher than (145.58 mg g-1) recorded in mung bean due largely to high presence of potassium (1.29 g 100 g-1) in cowpeas than in the former. Data from this study also showed that higher contents of flavonoids (11.31 mg g-1) make the mean content of phytochemicals in mung bean (4.21 mg g-1) to be slightly higher than but statistically (P?0.05) at par with that obtained in cowpea seeds (3.67 mg g-1). Generally, the nutrient contents in mung beans are not substantially higher than that of cowpea and vice versa. It is therefore recommended based on data obtained from this study that both be used to supplement each other in African diets due to their differential contents of flavonoids, magnesium, and potassium for better well-being and health.