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During the late 1990s commerce and academia voiced major concerns about the problems with development processes for Web Engineering. These concerns primarily centred upon the perceived chaotic and 'ad-hoc' approach to developing Web-based applications in extremely short time-scales when compared to traditional software development. Based on personal experience, conducting a survey of current practice, and collecting supporting evidence from the literature, I proposed a set of seven criteria that need to be addressed by a successful Web engineering process: 1. Short development life-cycle times; 2. Delivery of bespoke solutions and different business models; 3. Multidisciplinary development teams; 4. Small development teams working in parallel on similar tasks; 5. Business analysis and evaluation with end-users; 6. Requirements capture and rigorous testing; 7. Maintenance (evolution) of Web-based applications. These seven criteria are discussed in detail and the relevance of each to Web engineering is justified. They are then used to provide a framework to assess the suitability of a representative sample of well-known software engineering processes for Web engineering. The software engineering processes assessed comprise: the Unified Software Development Process; Dynamic Systems Development Method; and eXtreme Programming. These seven criteria were also used to motivate the definition of the Agile Web Engineering (AWE) process. A WE is based on the principles given in the Agile Manifesto and is specifically designed to address the major issues in Web Engineering, listed above. A number of other processes for Web Engineering have been proposed and a sample of these is systematically compared against the criteria given above. The Web engineering processes assessed are: Collaborative Web Development; Crystal Orange Web; Extensions to the Rational Unified Process; and Web OPEN. In order to assess the practical application of A WE, two commercial pilot projects were carried out in a Fortune 500 financial service sector company. The first commercial pilot of A WE increased end-user task completion on a retail Internet banking application from 47% to 79%. The second commercial pilot of A WE used by an Intranet development team won the company's global technology prize for 'value add' for 2003. In order to assess the effect of AWE within the company three surveys were carried out: an initial survey to establish current development practice within the company and two further surveys, one after each of the pilot projects. Despite the success of both pilots, AWE was not officially adopted by the company for Webbased projects. My surveys showed that this was primarily because there are significant cultural hurdles and organisational inertia to adopting different process approaches for different types of software development activity within the company. If other large companies, similar to the one discussed in this dissertation, are to adopt AWE, or other processes specific to Web engineering, then many will have to change their corporate goal of a one size fits all process approach for all software technology projects.

Το IPsec είναι ένα σύνολο πρωτοκόλλων με σκοπό να παρέχονται υπηρεσίες ασφάλειας σε επίπεδο πακέτων IP και εμπίπτει στη κατηγορία των εφαρμογών VPN. Το Linux είναι ένα σύγχρονο λειτουργικό σύστημα, ανοιχτού κώδικα με μεγάλη ευελιξία για χρήση σε διαφο- ρετικές αρχιτεκτονικές και εξαιρετική απόδοση σε πρωτόκολλα δικτύων. Αυτή η εργασία είναι προσανατολισμένη στην μελέτη της απόδοσης της υλοποίησης του IPsec σε Linux. Ορίζουμε τα μεγέθη που είναι σημαντικά για την αξιολόγηση της απόδοσης του IPsec, την μεθοδολογία των μετρήσεων, καθώς και τις παραμέτρους που καθορίζουν την απόδοση και στις οποίες μπορούμε να επέμβουμε με σκοπό να τη βελτιώσουμε. Μελετάμε τη συμπεριφορά σε διαφορετικά υπολογιστικά συστήματα και συγκρίνουμε την απόδοση με αυτή μια εναλλακτικής τεχνολογίας VPN, το OpenVPN. / IPsec is a suite of protocols that provides security services on IP layer, in a VPN fashion. Linux is a modern UNIX-like, Open Source operating system. It is suitable for a variety of applications, althought server oriented and exceptional performance on networking. We study the performance of the implementation of IPsec in Linux kernel. We define the performance measurements and criteria as well as the available options we cant fine-tune. We also study the aspect of performance on different achitectures. Finally we compare IPsec performance with OpenVPN, an alternative VPN solution.

This research work "Real-time Expressive Internet Communications" focuses on two subjects: One is the investigation of methods of automatic emotion detection and visualisation under real-time Internet communication environment, the other is the analysis of the influences of presenting visualised emotion expressivei mages to Internet users. To detect emotion within Internet communication, the emotion communication process over the Internet needs to be examined. An emotion momentum theory was developed to illustrate the emotion communication process over the Internet communication. It is argued in this theory that an Internet user is within a certain emotion state, the emotion state is changeable by internal and external stimulus (e.g. a received chat message) and time; stimulus duration and stimulus intensity are the major factors influencing the emotion state. The emotion momentum theory divides the emotions expressed in Internet communication into three dimensions: emotion category, intensity and duration. The emotion momentum theory was implemented within a prototype emotion extraction engine. The emotion extraction engine can analyse input text in an Internet chat environment, detect and extract the emotion being communicated, and deliver the parameters to invoke an appropriate expressive image on screen to the every communicating user's display. A set of experiments were carried out to test the speed and the accuracy of the emotion extraction engine. The results of the experiments demonstrated an acceptable performance of the emotion extraction engine. The next step of this study was to design and implement an expressive image generator that generates expressive images from a single neutral facial image. Generated facial images are classified into six categories, and for each category, three different intensities were achieved. Users need to define only six control points and three control shapes to synthesise all the expressive images and a set of experiments were carried out to test the quality of the synthesised images. The experiment results demonstrated an acceptable recognition rate of the generated facial expression images. With the emotion extraction engine and the expressive image generator,a test platform was created to evaluate the influences of emotion visualisation in the Internet communication context. The results of a series of experiments demonstratedthat emotion visualisation can enhancethe users' perceived performance and their satisfaction with the interfaces. The contributions to knowledge fall into four main areas; firstly, the emotion momentum theory that is proposed to illustrate the emotion communication process over the Internet; secondly, the innovations built into an emotion extraction engine, which senses emotional feelings from textual messages input by Internet users; thirdly, the innovations built into the expressive image generator, which synthesises facial expressions using a fast approach with a user friendly interface; and fourthly, the identification of the influence that the visualisation of emotion has on human computer interaction.

Les travaux présentés dans ce mémoire se placent dans le contexte de l'extension des technologies du Web à l'informatique enfouie. Le Web des objets qui en résulte ouvre les portes à de nouvelles interactions en garantissant une interopérabilité aussi bien au niveau réseau qu'applicatif. Nous adressons la conception du système logiciel jouant le rôle de serveur Web au sein d'équipements fortement contraints, tels que des cartes à puce ou des capteurs. Les solutions de l'état de l'art permettant de supporter une pile protocolaire standard à faible empreinte mémoire exigent de sacrifier les performances et les fonctionnalités du système. La thèse défendue est qu'en dédiant un système d'exploitation au support d'une famille d'applications de haut niveau, nous sommes en mesure de produire un logiciel performant et consommant très peu de ressources. Nous étudions une architecture basée sur un macro-noyau intégrant gestion du matériel, pile de communication et conteneur d'applications, présentant une interface adaptée aux besoins de ces dernières. / The context of this thesis is the extension of Web technologies to ambient computing. The resulting Web of Things allows novel interactions by guaranteeing interoperability at both network and applications levels. We address the design of the software system behaving as a Web server and embedded in strongly constrained devices such as smart cards or sensors. The state of the art solutions allowing to run a lightweight standard protocol stack involve poor performances and sacrifice the system features. The thesis is that by dedicating an operating system to the support of a high-level family of applications, we can produce an efficient software consuming a few resources. We study an architecture based on an macro-kernel integrating the hardware management, the communications stack and the applications container, providing an interface that fits the applications needs.

Semantic web content management poses much manual work onto the community. To reduce this labour we have devised Caravela1, a generic approach to dynamic content integration and automatic categorization. Content and documents of different types can be integrated from diverse semi-structured sources and categorized along multiple dimensions. Automatic linking provides dynamic categorizations at no user cost. We illustrate our approach by an online bibliography categorizing scientific research publications.

Σκοπός της εργασίας αυτής ήταν η θεωρητική ανάλυση των web services και η υλοποίηση ενός ηλεκτρονικού καταστήματος. Για να γίνει κατορθωτή η υλοποίησή του χρησιμοποιήθηκε ένα σύστημα διαχείρισης περιεχομένου, το Joomla. Το Joomla είναι ένα βραβευμένο σύστημα διαχείρισης περιεχομένου το οποίο μας δίνει τη δυνατότητα να οικοδομήσουμε ιστοσελίδες και ισχυρές online εφαρμογές .Είναι γραμμένο σε php, αποθηκεύει δεδομένα MySQL και περιλαμβάνει χαρακτηριστικά όπως η προσωρινή αποθήκευση σελίδας , RSS feeds, printable εκδόσεις των σελίδων, αναβοσβήνει ειδήσεις, blogs, δημοσκοπήσεις και έρευνα. Με τη βοήθειά του δημιουργήσαμε ένα ηλεκτρονικό κατάστημα και συγκεκριμένα ένα ηλεκτρονικό βιβλιοπωλείο που περιέχει δυο κατηγορίες βιβλίων. Με κλικάρισμα σε κάθε βιβλίο προβάλλονται οι λεπτομέρειες του προιόντος και δίνεται η δυνατότητα αγοράς του. / -

This research investigates the feasibility and usefulness of a Web-based model for end-user Web automation. The aim is to empower end users to automate their Web interactions. Web automation is defined here as the study of theoretical and practical techniques for applying an end-user programming model to enable the automation of Web tasks, activities, or interactions. To date, few tools address the issue of Web automation; moreover, their functionality and usage are limited. A novel model is presented, which combines end-user programming techniques and the software tools philosophy with the vision of the “Web as a platform.” The model provided a Web-based environment that enables the rapid creation of efficient and useful Web-oriented automation tools. It consists of a command line for the Web, a shell scripting language, and a repository of Web commands. A framework called Web2Sh (Web 2.0 Shell) has been implemented, which includes the design and implementation of scripting language (WSh) enabling end users to create and customise Web commands. A number of Web2Sh-core Web commands were implemented. There are two techniques for extending the system: developers can implement new core Web commands, and the use of WSh by end users to connect, customise, and parameterise Web commands to create new commands. The feasibility and the usefulness of the proposed model have been demonstrated by implementing several automation scripts using Web2Sh, and by a case study based experiment that was carried out by volunteered participants. The implemented Web2Sh framework provided a novel and realistic environment for creating, customising, and running Web-oriented automation tools.

Η παρούσα διπλωματική εργασία παρουσιάζει το πρόβλημα της εξάντλησης των IPv4 διευθύνσεων καθώς και τη διαδικασία μετάβαση στο IPv6. Πιο συγκεκριμένα, παρουσιάζονται τεχνολογίες και τεχνικές που έχουν προταθεί σε διεθνή forum για την μετάβαση από IPv4 σε IPv6 και αφορούν MPLS δίκτυα telecom provider. Στο 5ο κεφάλαιο δημιουργείται ένα περιβάλλον εξομοίωσης δικτυακών συσκευών και προσομοιώνονται βέλτιστες πρακτικές. Πολλοί providers έχουν επενδύσει τα τελευταία χρόνια στην εγκατάσταση IPv4-MPLS για τα δίκτυα κορμού τους. Από μια τέτοια μακροχρόνια επένδυση είναι λογικό μία επιχείρηση να περιμένει οφέλη. Η υποστήριξη IPv6 πάνω από το ήδη υπάρχον IPv4-MPLS θα απέδιδε τα μέγιστα οφέλη για μια τέτοια επιχείρηση. Έτσι μια τέτοια μετάβαση αποτελεί στρατηγική κίνηση που ουσιαστικά σκοπεύει στην αύξηση των κερδών του καθώς και την προετοιμασία του για το μέλλον. / This thesis aims to present the issue of constantly-decreasing available IPv4 addresses as well as the related transition process to IPv6, before the fully elimination of IPv4. More specifically, in this thesis there will be presented technologies and techniques which have been recommended in several international forums in relation to transition from IPv4 to IPv6 and which concern the MPLS networks for telecom providers. In the fifth chapter, an emulation environment for network devices will be “created”, through which some of the most appropriate transition implementation practices will be simulated. During the last years several providers have invested in installing IPv4-MPLS for their core networks. From such a long-term investment is sensible that one business expects profits. According to Chapter 5, the transition to IPv6 in conjunction with the full utilization of existing IPv4-MPLS equipment would have significant benefits for any business decided to proceed with this option. In particular, such a transition (from IPv4 to IPv6) could be part of a business strategy since not only contributes to the technological upgrading of a company’s systems and the production of more reliable services, but also to create synergies and economies of scale.