Since a massive decline of computer science graduates in 2002, computer science departments have been unable to reach previous graduation rates. In wake of this dramatic loss of graduates, researchers have been searching for the reasons students are avoiding computer science and choosing other majors. To combat this decrease in computer science graduates, the CloudSpace environment pro- vides additional context to entry level computer science courses. This shift in context re- moves boring assignments from the early computer science curriculum and replaces them with more engaging web centric assignments. The CloudSpace environment presents a model that maintains student's focus on core computer science competencies while providing a highly simplified web development toolkit to develop feature rich AJAX web applications. This the- sis includes the rational and implementation of a cloud based hosting service and a highly abstracted web tool kit that enables students to replicate modern web applications. / Master of Science

The traditional way to coordinate multiple clients in a multiplayer based game on multiple platforms is to create an implementation on a per-platform basis - resulting in often four different implementations, one for each major platform - ie. iOS, Android, Windows, and Linux based operating systems. This report examines the possibility of replacing multiple so called “native apps” with a single web based implementation - granting users access on all devices that supports modern browsers, and discusses what tools were used in the development of the application and why. / Det vanliga sättet att hantera multipla klienter i spel med flerspelarlägen är att utveckla unika implementationer på en per-plattform basis - alltså att samma applikation kräver en unik implementation för var plattform som skall stödjas. Vanligtvis görs en unik implementation för iOS, Android, Windows och Unix-baserade operativsystem vardera. Denna rapport undersöker möjligheten att ersätta dessa implementationer med en unison webbaserad implementation som tillåter alla enheter ​med stöd för moderna webbläsare att använda applikationen och diskuterar vilka verktyg som använts och varför.

This document discusses the visualization of data in the web environment using JavaScript and PHP. Specifically, create a web application for dynamically displaying time series in an interactive environment via the REST API in JSON format. There are described technologies for creating web applications and their use. This is work involving designing and creating a web application.

Στα πλαίσια αυτής της εργασίας έγινε μια απόπειρα καταγραφής και μελέτης των δυνατοτήτων που παρέχονται σήμερα για την ανάπτυξη δικτυακών εφαρμογών σε περιβάλλον Java με χρήση της τεχνολογίας Ajax. Στα πρώτα τρία κεφάλαια γίνεται μια συνοπτική αναφορά σε κάποιες κεντρικές έννοιες και εργαλεία ανάπτυξης Web εφαρμογών σε περιβάλλον Java πρίν την εμφάνιση του Ajax, όπως η γλώσσα HTML, η γλώσσα Javascript, και οι τεχνολογίες που ανέπτυξε η εταιρία Sun για αυτό το σκοπό. Επίσης περιγράφονται κάποια δημοφιλή αυτόνομα εργαλεία ανάπτυξης που στηρίχθηκαν στις παραπάνω τεχνολογίες και τις επέκτειναν. Το αντικείμενο του κεφαλαίου 4 είναι η τεχνολογία Ajax και ο βασικός μηχανισμός πίσω από αυτήν, δηλαδή το αντικείμενο XHR της Javascript. Στο κεφάλαιο 5 γίνεται λόγος για τα frameworks που είναι διαθέσιμα σήμερα και παρέχουν ενσωμάτωση της νέας τεχνολογίας σε εφαρμογές Java, και εισάγεται ένας βασικός διαχωρισμός ανάμεσα στα Direct Ajax Frameworks και στα Indirect Ajax Frameworks. Αυτός ο διαχωρισμός αφορά κυριώς διαφορετικές προσεγγίσεις σε θέματα ανάπτυξης και συνεργασίας με άλλες τεχνολογίες, και γίνεται πιο σαφής στα κεφάλαια 6 και 7. Στο κεφάλαιο 6 περιγράφεται η κατηγορία των Direct Ajax Frameworks, τα κοινά χαρακτηριστικά τους, οι τρόποι χρήσης τους και παρατίθενται λεπτομέρειες για κάποια από τα δημοφιλή frameworks της κατηγορίας. Στο κεφάλαιο 7 περιέχονται αντίστοιχα στοιχεία για την κατηγορία των Indirect Java Ajax Frameworks. Το κεφάλαιο 8 αφορά την υλοποίηση που έγινε στα πλαίσια της εργασίας. Το αντικείμενο της ήταν η προσθήκη στοιχείων της τεχνολογίας Ajax σε μια ήδη υπάρχουσα Java Web εφαρμογή χρησιμοποιώντας δυο διαφορετικά δημοφιλή Ajax Frameworks. Στόχος της υλοποίησης ήταν να γίνει μια εκτίμηση της ευκολία χρήσης, για κάθε ένα από τα δυο frameworks, και της ποιότητας του αποτελέσματος. Τέλος, στο κεφάλαιο 9 συνοψίζονται τα χαρακτηριστικά, τα πλεονεκτήματα και τα μειονεκτήματα των Frameworks που περιγράφηκαν, και αποτυπώνονται κάποια συνολικά συμπεράσματα για τους τρόπους χρήσης της τεχνολογίας και τις δυνατότητες που αυτή παρέχει. / -

The Semantic Web enables people and computers to interact and exchange information. Based on Semantic Web technologies, different machine learning applications have been designed. Particularly to emphasize is the possibility to create complex metadata descriptions for any problem domain, based on pre-defined ontologies. In this paper we evaluate the use of a semantic similarity measure based on pre-defined ontologies as an input for a classification analysis. A link prediction between actors of a social network is performed, which could serve as a recommendation system. We measure the prediction performance based on an ontology-based metadata modeling as well as a feature vector modeling. The findings demonstrate that the prediction accuracy based on ontology-based metadata is comparable to traditional approaches and shows that data mining using ontology-based metadata can be considered as a very promising approach.

Η αλματώδης εξέλιξη που σημειώθηκε και εξακολουθεί να σημειώνεται τα τελευταία χρόνια στις τεχνολογίες του παγκόσμιου ιστού, έχει οδηγήσει σε προσπάθεια ενσωμάτωσεις του παγκόσμιου ιστού (Web) σε όλες τις πτυχές της ζωής με στόχο την παροχή καλύτερων και πιο αποδοτικών υπηρεσιών. Το Web έχει εξελιχθεί τα τελευταία χρόνια με πάρα πολύ γοργούς ρυθμούς και σε συνδυασμό με τις εξελίξεις στις τεχνολογίες επικοινωνιών και ιδιαίτερα με την παροχή αξιόπιστων και ταχύτατων ευρυζωνικών δικτύων επικοινωνίας, έχει μετεξελιχθεί σε μία πλατφόρμα παροχής προηγμένων δικτυακών υπηρεσιών οι οποίες καλύπτουν ένα ευρύτατο φάσμα εκπαιδευτικών αναγκών. Αυτό σε συνδυασμό με την σημασία που δίνεται παγκοσμίως στην εκπαιδευτική διαδικασία και στη σχέση που έχει η εκπαίδευση με την εξέλιξη και ανάπτυξη της κοινωνίας και της οικονομίας έχει οδηγήσει σε εκτεταμένες μελέτες και αναλύσεις σχετικά με την ενσωμάτωση των νέων τεχνολογιών και ιδιαίτερα των σχετικών με τον παγκόσμιο ιστό τεχνολογιών στην εκπαιδευτική διαδικασία από τα πρώιμα στάδια μέχρι και την τριτοβάθμια εκπαίδευση. Στην εργασία αυτή γίνεται προσπάθεια να προσδιοριστεί το κοινωνικό και οικονομικό πλαίσιο μέσα στο οποίο εξελίσεται ο τομέας της εκπαίδευσης σε όλο της το φάσμα και να αποτυπωθούν οι διάφορες τάσεις σε σχέση με τις νέες τεχνολογικές προσεγγίσεις και ιδιαίτερα με τις τεχνολογίες παγκοσμίου ιστού και τον τρόπο με τον οποίο αυτές επηρεάζουν την εκπαίδευση. Παρουσιάζεται συνοπτικά το πλαίσιο μέσα στο οποίο επιχειρήται η ενσωμάτωση των τεχνολογιών πληροφορικής και επικοινωνιών στην εκπαιδευτική διαδικασία και γίνεται αναφορά σε προγράμματα και δράσεις που υλοποιούνται και έχουν υλοποιηθεί στην Ευρωπαϊκή Ένωση και στην Ελλάδα, καθώς και σε καλές πρακτικές εφαρμογές τεχνολογιών παγκοσμίου ιστού στην εκπαίδευση σε χώρες της ΕΕ και στην Ελλάδα. Στη συνέχεια παρουσιάζονται αναλυτικά οι διάφορες τεχνολογίες και υπηρεσίες που συνθέτουν τον παγκόσμιο ιστό με ιδιαίτερη αναφορά στις πιο σύγχρονες από αυτές. Γίνεται μία προσπάθεια να παρουσιαστεί ο τρόπος με τον οποίο οι τεχνολογίες και οι υπηρεσίες αυτές επηρεάζουν ή μπορούν να επηρεάσουν την εκπαιδευτική διαδικασία στο σύνολό της και η δυναμική που αυτές αναπτύσσουν. Τέλος, παρουσιάζεται το εκπαιδευτικό λογισμικό ΙΣΤΟΠΟΛΙΣ, το οποίο αποτελεί ένα δικτυακό υπερμεσικό εκπαιδευτικό περιβάλλον με στόχο τη διδασκαλία στην τάξη σε γνωστικά αντικείμενα όπως η Ιστορία και το οποίο αναπτύχθηκε χρησιμοποιώντας σύγχρονες τεχνολογίες παγκοσμίου ιστού. / The huge evolution in web technologies which took place and continues to take place the last years leads to an effort to integrate these technologies in all aspects of human life, in order to provide better and more efficient services to everyone. Web has developed rapidly the last years. The development in the communication technologies and especially the provision of reliable and high rate broadband communication networks has lead to a platform which can provide advanced network services that cover a broad spectrum of educational needs. The above mentioned, in combination with the importance that the educational procedure has and the relation of education to the development and progress of the society and economy, have lead to thorough studies and research concerning the integration of the new information and communication technologies (ICT) - and especially those related to the World Wide Web - in the learning procedure from primary school to higher education. In this master thesis an effort is being made to define the social and economical framework within which the educational sector is functioning and to outline the various tendencies concerning the new technological approaches and the way they affect education. Moreover the thesis provides an overview of the framework within which the integration of computer technologies in education is taking place and references to various programs and actions that are taking place in European Union and Greece. In addition some good examples are being mentioned as far as good practices in European countries and Greece are concerned. Furthermore, there is a detailed presentation of the various technologies and services that constitute the WWW with special reference to the most contemporary of them and of the way in which these technologies and services affect or could affect the education and the potential that they have. Finally, there is a presentation of the educational software ISTOPOLIS, which is a hypermedia educational environment which provides an alternative or complementary way of teaching in the classroom and which has been developed using some of the most modern web technologies.

Centruflow is an application that can be used to visualise structured data. It does this by drawing graphs, allowing for users to explore information relationships that may not be visible or easily understood otherwise. This helps users to gain a better understanding of their organisation and to communicate more effectively. In earlier versions of Centruflow, it was difficult to develop new functionality as it was built using a relatively unsupported and proprietary visualisation toolkit. In addition, there were major issues surrounding information currency and trust. Something had to be done, and this was a sub-project of this thesis. The main purpose of this thesis however was to research and develop a set of mathematical algorithms to infer implicit relationships in Centruflow data sources. Once these implicit relationships were found, we could make them explicit by showing them within Centruflow. To enable this, relationships were to be calculated based on providing users with the ability to 'tag' resources with metadata. We believed that by using this tagging metadata, Centruflow could offer users far more insight into their own data. Implementing this was not a straight-forward task, as it required a considerable amount of research and development to be undertaken to understand and appreciate technologies that could help us in our goal. Our focus was primarily on technologies and approaches common in the semantic web and 'Web 2.0' areas. By pursuing semantic web technologies, we ensured that Centruflow would be considerably more standards-compliant than it was previously. At the conclusion of our development period, Centruflow had been rather substantially 'retrofitted', with all proprietary technologies replaced with equivalent semantic web technologies. The result of this is that Centruflow is now positioned on the forefront of the semantic web wave, allowing for far more comprehensive and rapid visualisation of a far larger set of readily-available data than what was possible previously. Having implemented all necessary functionality, we validated our approach and were pleased to find that our improvements led to a considerably more intelligent and useful Centruflow application than was previously available. This functionality is now available as part of 'Centruflow 3.0', which will be publicly released in March 2008. Finally, we conclude this thesis with a discussion on the future work that should be undertaken to improve on the current release.

Centruflow is an application that can be used to visualise structured data. It does this by drawing graphs, allowing for users to explore information relationships that may not be visible or easily understood otherwise. This helps users to gain a better understanding of their organisation and to communicate more effectively. In earlier versions of Centruflow, it was difficult to develop new functionality as it was built using a relatively unsupported and proprietary visualisation toolkit. In addition, there were major issues surrounding information currency and trust. Something had to be done, and this was a sub-project of this thesis. The main purpose of this thesis however was to research and develop a set of mathematical algorithms to infer implicit relationships in Centruflow data sources. Once these implicit relationships were found, we could make them explicit by showing them within Centruflow. To enable this, relationships were to be calculated based on providing users with the ability to 'tag' resources with metadata. We believed that by using this tagging metadata, Centruflow could offer users far more insight into their own data. Implementing this was not a straight-forward task, as it required a considerable amount of research and development to be undertaken to understand and appreciate technologies that could help us in our goal. Our focus was primarily on technologies and approaches common in the semantic web and 'Web 2.0' areas. By pursuing semantic web technologies, we ensured that Centruflow would be considerably more standards-compliant than it was previously. At the conclusion of our development period, Centruflow had been rather substantially 'retrofitted', with all proprietary technologies replaced with equivalent semantic web technologies. The result of this is that Centruflow is now positioned on the forefront of the semantic web wave, allowing for far more comprehensive and rapid visualisation of a far larger set of readily-available data than what was possible previously. Having implemented all necessary functionality, we validated our approach and were pleased to find that our improvements led to a considerably more intelligent and useful Centruflow application than was previously available. This functionality is now available as part of 'Centruflow 3.0', which will be publicly released in March 2008. Finally, we conclude this thesis with a discussion on the future work that should be undertaken to improve on the current release.

Centruflow is an application that can be used to visualise structured data. It does this by drawing graphs, allowing for users to explore information relationships that may not be visible or easily understood otherwise. This helps users to gain a better understanding of their organisation and to communicate more effectively. In earlier versions of Centruflow, it was difficult to develop new functionality as it was built using a relatively unsupported and proprietary visualisation toolkit. In addition, there were major issues surrounding information currency and trust. Something had to be done, and this was a sub-project of this thesis. The main purpose of this thesis however was to research and develop a set of mathematical algorithms to infer implicit relationships in Centruflow data sources. Once these implicit relationships were found, we could make them explicit by showing them within Centruflow. To enable this, relationships were to be calculated based on providing users with the ability to 'tag' resources with metadata. We believed that by using this tagging metadata, Centruflow could offer users far more insight into their own data. Implementing this was not a straight-forward task, as it required a considerable amount of research and development to be undertaken to understand and appreciate technologies that could help us in our goal. Our focus was primarily on technologies and approaches common in the semantic web and 'Web 2.0' areas. By pursuing semantic web technologies, we ensured that Centruflow would be considerably more standards-compliant than it was previously. At the conclusion of our development period, Centruflow had been rather substantially 'retrofitted', with all proprietary technologies replaced with equivalent semantic web technologies. The result of this is that Centruflow is now positioned on the forefront of the semantic web wave, allowing for far more comprehensive and rapid visualisation of a far larger set of readily-available data than what was possible previously. Having implemented all necessary functionality, we validated our approach and were pleased to find that our improvements led to a considerably more intelligent and useful Centruflow application than was previously available. This functionality is now available as part of 'Centruflow 3.0', which will be publicly released in March 2008. Finally, we conclude this thesis with a discussion on the future work that should be undertaken to improve on the current release.

Centruflow is an application that can be used to visualise structured data. It does this by drawing graphs, allowing for users to explore information relationships that may not be visible or easily understood otherwise. This helps users to gain a better understanding of their organisation and to communicate more effectively. In earlier versions of Centruflow, it was difficult to develop new functionality as it was built using a relatively unsupported and proprietary visualisation toolkit. In addition, there were major issues surrounding information currency and trust. Something had to be done, and this was a sub-project of this thesis. The main purpose of this thesis however was to research and develop a set of mathematical algorithms to infer implicit relationships in Centruflow data sources. Once these implicit relationships were found, we could make them explicit by showing them within Centruflow. To enable this, relationships were to be calculated based on providing users with the ability to 'tag' resources with metadata. We believed that by using this tagging metadata, Centruflow could offer users far more insight into their own data. Implementing this was not a straight-forward task, as it required a considerable amount of research and development to be undertaken to understand and appreciate technologies that could help us in our goal. Our focus was primarily on technologies and approaches common in the semantic web and 'Web 2.0' areas. By pursuing semantic web technologies, we ensured that Centruflow would be considerably more standards-compliant than it was previously. At the conclusion of our development period, Centruflow had been rather substantially 'retrofitted', with all proprietary technologies replaced with equivalent semantic web technologies. The result of this is that Centruflow is now positioned on the forefront of the semantic web wave, allowing for far more comprehensive and rapid visualisation of a far larger set of readily-available data than what was possible previously. Having implemented all necessary functionality, we validated our approach and were pleased to find that our improvements led to a considerably more intelligent and useful Centruflow application than was previously available. This functionality is now available as part of 'Centruflow 3.0', which will be publicly released in March 2008. Finally, we conclude this thesis with a discussion on the future work that should be undertaken to improve on the current release.