Synchronising Wisdom and Implementation: A Formal ODD Approach to Expressing Insights on Bullying

Paper IV and V is excluded from the dissertation until it is published.The Social Simulation methodology, a mix of traditionally unassociated fields, utilises computer models to describe, understand, predict, and reflect on social phenomena. The model creation process typically requires the integration of knowledge insights from academic and non-academic knowledge holders. To ensure model quality, different processes are established in an effort to verify the alignment of knowledge insights and their implementation in the simulation model by the modelling team. However, due to a lack of technical skills, knowledge holders, who may not fully understand the model code, often perform these verification checks indirectly, for example by evaluating conceptual model descriptions. Initially motivated to create quality models of social conflict, this dissertation approaches the model quality challenge with a Domain Specific Modelling (DSM) approach. The objective was to develop a DSM tool using the Design Methodology, supplemented by a case study to provide first-hand experience with the quality challenge. Based on our project requirements, we selected University bullying as the case study subject. The Design Methodology included the problem exploration, the identification of a DSM solution, the selection of a domain and programming language for the DSM tool, the agile development of the domain language aspects with test models, and a final evaluation using the case study model.acceptedVersio

On abstraction in the OMG hierarchy: systems, models, and descriptions

The Model-Driven Architecture (MDA) uses a metadata hierarchy with several layers that are placed on top of each other. The traditional view is that the layers provide abstractions related to models in languages defined by meta-models. Over the years, it has been difficult to define a consistent understanding of the layers. In this paper, we propose such a consistent understanding by clarifying the relations between the different elements in the hierarchy. This is done based on the Scandinavian approach to modelling that distinguishes between systems and system descriptions. Systems can be physical, digital, or even mental, while descriptions can be programs, language descriptions, specifications, and diagrams. We relate descriptions and systems by explaining where semantics of objects originate and how they apply in the hierarchy.publishedVersionPaid Open Acces

Modeling Marginalization: Emergence, Social Physics, and Social Ethics of Bullying

In this paper, we outline the construction and initial simulation experiment results of the Marginalization model (MARG). We experiment under different group parameters because the theoretical paradigm we follow views bullying as a result of social processes. Our primary research question explores the possibility of bullying emergence as agents select interaction partners in a university setting. Based on the simulated process, our results take indications of the stress of marginalization in a student group as a proxy for emer-gent marginalization. MARG simulates two types of interactions between pairs of students: forced and hang-out interactions. In the latter, students decide whether to interact based on individual preferences formed by social norms and individual tolerance related to those norms. The emergence of intensified mar-ginalization from MARG processes leads to some ethical considerations and provides ground for discus-sions concerning suitable interventions.submittedVersio

Models, systems, and descriptions - A cross-disciplinary reflection on models

There are many different notions of models in different areas of science that are often not aligned, making it difficult to discuss them across disciplines. In this study, we look at the differences between physical models and mental models as well as the difference between static and dynamic models. Semiotics provides a philosophical underpinning by explaining meaning-making. This allows for identifying a common ground between models in different areas. We use examples from natural sciences and linguistics to illustrate different approaches and concepts and to find commonalities. This study distinguishes between systems, models, and descriptions of models. This distinction allows us to understand the commonalities of mental and physical models in different areas.publishedVersio

Analysis of a past irrigation system in Oman

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

Production of Nano-zerovalent iron with plant extracts and fruit juices.

106 σ.Ο στοιχειακός νανοσίδηρος (nZVI, nano Zero Valent Iron) θεωρείται ένα ισχυρότατο αντιδραστήριο για πλήθος περιβαλλοντικών και άλλων εφαρμογών και η ανάπτυξη αποτελεσματικών μεθόδων για την παραγωγή του αποτελεί ένα πεδίο έντονης ερευνητικής δραστηριότητας. Η αξιοποίηση φυτικών εκχυλισμάτων για τη σύνθεση και σταθεροποίηση του στοιχειακού νανοσιδήρου συνιστά μια ιδιαίτερα ελκυστική μέθοδο, με σημαντικά τεχνολογικά και περιβαλλοντικά πλεονεκτήματα. Συγκεκριμένα, οι πολυφαινόλες που υπάρχουν σε ορισμένα φυτικά εκχυλίσματα δρουν σαν ισχυρά αναγωγικά αντιδραστήρια μετατρέποντας τα υδατοδιαλυτά ιόντα Fe(III) σε νανοσωματίδια στοιχειακού σιδήρου, Fe(0), και παράλληλα δημιουργούν προστατευτικό επιφανειακό στρώμα γύρω από τα νανοσωματίδια, που συμβάλλει στη φυσική και χημική σταθεροποίηση του αιωρήματος. Στη μελέτη αυτή αξιολογήθηκε η δυνατότητα χρήσης εκχυλισμάτων από δύο βότανα και ένα μπαχαρικό, δηλαδή ΠράσινοΤσάι (GT, Green Tea), Δυόσμο (SM, Spearmint) και Γαρύφαλλο (CL, clove), καθώς και η δυνατότητα αξιοποίησης χυμών φρούτων, δηλαδή χυμού Ροδιού (PG, Pomegranate) και κόκκινου κρασιού (Red Wine, RW). Οι παράμετροι που εξετάσθηκαν ήταν οι συνθήκες παρασκευής των εκχυλισμάτων, η αναλογία ανάμιξης φυτικού εκχυλίσματος-διαλύματος Fe(III), καθώς και η αποτελεσματικότητα των αιωρημάτων nZVI που προκύπτουν, ως προς την αναγωγή του εξασθενούς τοξικού, Cr(VI), στην περιβαλλοντικά ασφαλή τρισθενή μορφή, Cr(III). H μέγιστη απόσπαση των πολυφαινολών από τα βότανα (με εκχύλιση σε ζεστό νερό 80ο C), ανά μονάδα βάρους του φυτού, διαπιστώθηκε ότι επιτυγχάνεται σε αναλογία βοτάνου-νερού S/L =10 με 20 g/L. Όταν η εκχύλιση πραγματοποιήθηκε σε αναλογία S/L=20 g/L, η υψηλότερη συγκέντρωση πολυφαινολών επιτεύχθηκε με το λειοτριβημένο γαρύφαλλο, 3040 mg GAE/L (GAE, gallic acid equivalents), και ακολούθησαν τα εκχυλίσματα πράσινου τσαγιού (GT) και δυόσμου (SM), με συγκεντρώσεις 1940 και 1059 mg GAE/L. Υψηλές συγκεντρώσεις πολυφαινολών βρέθηκε ότι περιέχουν και οι δύο χυμοί. Συγκεκριμένα μετρήθηκαν 3400 mg GAE/L στο χυμό ροδιού (PG) και 2400 mg GAE/L στο δείγμα κόκκινου κρασιού (RW). Σε όλες τις συνθήκες που εξετάστηκαν η αναγωγή του Fe(III) σε νανοσίδηρο με τη χρήση των φυτικών εκχυλισμάτων και χυμών ήταν μερική και δεν ξεπέρασε το ποσοστό του 50%. Η μέγιστη συγκέντρωση στοιχειακού νανοσιδήρου nZVI ήταν της τάξης του 1.2 g/L (22 mM) και προέκυψε χρησιμοποιώντας κόκκινο κρασί και χυμό ροδιού. Το πράσινο τσάι και το λειοτριβημένο γαρύφαλλο έδειξαν παραπλήσια αποτελεσματικότητα με μέγιστη συγκέντρωση νανοσιδήρου περίπου 1 g/L (18 mM). Τα εκχυλίσματα δυόσμου ήταν λιγότερο αποτελεσματικά. Στις δοκιμές αναγωγής του Cr(VI) με τη χρήση των αιωρημάτων nZVI, διαπιστώθηκε ότι με μικρή σχετικά στοιχειομετρική περίσσεια nZVI προς Cr(VI), δηλ. nZVI/Cr(VI) ≈1.8 mole/mole (με στοιχειμετρική αναλογία αντίδρασης nZVI/Cr(VI) =1 mole/mole), επιτυγχάνεται πλήρης αναγωγή του εξασθενούς χρωμίου. Δεν υπάρχει δηλαδή σημαντική κατανάλωση του nZVI από παράπλευρες αντιδράσεις, π.χ. από το οξυγόνο της ατμόσφαιρας. Η κινητική της αντίδρασης ήταν ταχεία και στις περισσότερες περιπτώσεις η αναγωγή ολοκληρώθηκε σε χρόνο μικρότερο των 5 λεπτών. Ένα πολύ εντυπωσιακό αποτέλεσμα της μελέτης, ήταν η επιτυχής αναγωγή 485mg εξασθενούς χρωμίου με την κατανάλωση 1g νανοσιδήρου, ποσότητα πολύ μεγαλύτερη από την ποσότητα που έχει παρατηρηθεί σε άλλες μελέτες (50-180mg εξασθενούς χρωμίου ανά 1g νανοσιδήρου).Νano Zero Valent Iron (nZVI) is considered a powerful tool for numerous environmental and other applications and the development of efficient methods for its production is a fast growing research field. The use of plant extracts for the synthesis and stabilization of nZVI is a particularly attractive method with significant technological and environmental advantages. The polyphenols, which are found in some plant extracts, act as powerful reducing reagents converting soluble ions Fe(III) to nanoparticles of elemental iron, Fe(0), while creating a protective surface layer around the nanoparticles. This layer contributes to the physical and chemical stabilization of the suspension. The present study evaluated the possibility of using extracts of two herbs and a spice, Green Tea (GT), Spearmint (SM) and Clove (CL), and the possibility of using fruit juices, Pomegranate (PG) and Red Wine (RW). The examined parameters were the conditions under which the extracts were prepared, the mixing ratio of herbal extract with a FeCl3 0.1 M solution, and the efficiency of the produced nZVI suspensions for the chemical reduction of toxic hexavalent chromium, Cr(VI), in the environmentally safe trivalent form, Cr (III). The maximum extraction of polyphenols during the leaching of herbs with hot water (80oC) was obtained mixing 10-20 grams of herbs per liter of water (S/L=10-20 g/L). In the plant extracts which were produced with S/L=20 g/L, the highest concentration of polyphenols was measured in the extract of ground clove (CL), 3040 mg GAE/L (GAE, gallic acid equivalents), followed by the extracts of green tea (GT) and spearmint (SM) where the measured concentrations were 1940 and 1059 mg GAE/L. High polyphenol concentrations were also measured in the PG juice and the RW sample, i.e. 3400 mg GAE/L and 2400 mg GAE/L respectively. In the experiments that were carried out mixing the plant extracts with the FeCl3 solution, the reduction of iron was always partial, not exceeding the percentage of 50%.The maximum concentration of elemental nanoiron, nZVI, was about 1.2 g/L (22 mM) and was obtained using red wine and pomegranate juice. Green tea and ground cloves showed similar efficacy, with maximum nZVI concentration about 1 g/L (18 mM). Spearmint extracts were less effective. The experiments that were carried out using nZVI suspensions for the reduction of Cr(VI) showed that a small stoichiometric excess of nZVI with respect to Cr(VI), i.e. nZVI / Cr (VI)≈ 1.8 mole/mole (stoichiometric value nZVI / Cr (VI)=1 mole/mole), is sufficient for obtaining complete reduction of hexavalent chromium to the trivalent state. This is an indication, that nZVI is not consumed by undesirable side reactions, such as the atmospheric oxygen. The kinetics of the reaction was rapid, and in most cases, the reduction was complete in less than 5 minutes. A very impressive result of the study was the successful reduction of 485mg of hexavalent chromium with the consumption of 1g of nZVI. The amount of reduction is much higher than the amount expected from other studies (reduction of 50-180mg hexavalent chromium with consumption of 1g of nZVI).Θέμις-Δήμητρα Θ. Ξανθοπούλο

Modeling Marginalization: Emergence, Social Physics, and Social Ethics of Bullying

In this paper, we outline the construction and initial simulation experiment results of the Marginalization model (MARG). We experiment under different group parameters because the theoretical paradigm we follow views bullying as a result of social processes. Our primary research question explores the possibility of bullying emergence as agents select interaction partners in a university setting. Based on the simulated process, our results take indications of the stress of marginalization in a student group as a proxy for emer-gent marginalization. MARG simulates two types of interactions between pairs of students: forced and hang-out interactions. In the latter, students decide whether to interact based on individual preferences formed by social norms and individual tolerance related to those norms. The emergence of intensified mar-ginalization from MARG processes leads to some ethical considerations and provides ground for discus-sions concerning suitable interventions