<p>This thesis covers design and implementation of a media system solution for home networks with personal computers and a set-top box. </p><p>In a home there are effectively two independent media systems with the same purpose: the personal computer and the digital set-top box, with the purpose of delivering digital media in form of audio and video to the consumer.</p><p>The goal of the thesis work was to implement a solution that bridges the gap between the two systems, so that the user, from the set-top box, can play back media that is actually stored on one or several personal computers. </p><p>Our solution is based on UPnP technology, which is used for service discovery and control. The choice of UPnP is motivated by an evaluation of discovery protocols, which concludes that UPnP is the most suitable technology in this particular system. Also, an evaluation of suitable transport protocols was done. Here,HTTP was used. </p><p>For the personal computer, a media server and a graphical user interface for configuring the media server were created. For the set-top box, a media client, and a graphical user interface for browsing the content of the media server, were created. In conclusion, the creation of the prototype was successful and the set-top box was able to playback media that had been shared by the PC on the network.</p>

The Web turns out to be a collection of services that interoperate through the Internet. As the number of services increase, it is getting more and more diffucult for users to find, filter and integrate these services depending on their requirements. Automatic techniques are being developed to fulfill these tasks. The first step toward automatic composition is the discovery of services needed. UDDI which is one of the accepted web standards, provides a registry of web services. However representation capabilities of UDDI are insufficient to search for services on the basis of what they provide. Semantic web initiatives like OWL and OWL-S are promising for locating exact services based on their capabilities. In this thesis, a new semantic service discovery mechanism is implemented based on OWL-S service profiles. The service profiles of an advertisement and a request are matched based on OWL ontologies describing them. In contrast to previous work on the subject, the ontologies of the advertisement and the request are not assumed to be same. In case they are different, schema matching algorithms are applied. Schema matching algorithms find the mappings between the given schema models. A hybrid combination of semantic, syntactic and structural schema matching algorithms are applied to match ontologies

Web Service technology is one of the most rapidly developing contemporary technologies. Nowadays, Web Services are being used by a large number of projects and academic studies all over the world. As the use of Web service technology is increasing, it becomes harder to find the most suitable web service which meets the Quality of Service (QoS) as well as functional requirements of the user. In addition, quality of the web services (QoS) that take part in the software system becomes very important. In this thesis, we develop a method to track the QoS primitives of Web Services and an algorithm to automatically calculate QoS values for Web Services. The proposed method is realized within a domain specific web service discovery system, namely DSWSD-S, Domain Specific Web Service Discovery with Semantics. This system searches the Internet and finds web services that are related to a domain and calculates QoS values through some parameters. When a web service is queried, our system returns suitable web services with their QoS values. How to calculate, keep track of and store QoS values constitute the main part of this study.

Τα τελευταία χρόνια η ανάπτυξη των Ανοιχτών Συστημάτων Υπερκειμένου (ΑΣΥ) είναι ευρεία με την προσθήκη νέων πεδίων και αρχιτεκτονικών που βοηθούν στην καλύτερη οργάνωση της πληροφορίας με στόχο την εξομοίωση και επαύξηση της σκέψης του ανθρώπου στο συγκεκριμένο τομέα. Ωστόσο, η χρησιμοποίηση των ΑΣΥ από το ευρύ κοινό είναι πολύ μικρή διότι η κατηγορία των συστημάτων αυτών δεν έχει καταφέρει μέχρι στιγμής να γίνει γνωστή για τα πλεονεκτήματα που προσφέρει όσον αφορά τη διαχείριση, τη δόμηση και τη σύνδεση της πληροφορίας. Επίσης, η κοινωνία των ΑΣΥ δεν έχει ακόμα παγιώσει κοινές μεθοδολογίες και υποδομές που θα βοηθούσαν κάθε developer να εισάγει εύκολα στην εφαρμογή του λειτουργίες υπερκειμένου. Στην παρούσα Μεταπτυχιακή εργασία γίνεται μια προσπάθεια για την ανάπτυξη μιας υποδομής που βοηθά τον developer στην εύκολη ενσωμάτωση υπηρεσιών υπερκειμένου στην εφαρμογή του. Έτσι, μελετήθηκε, σχεδιάστηκε και υλοποιήθηκε ο τρόπος με τον οποίο μπορεί να γίνει ανακάλυψη υπηρεσιών (service discovery) στα σύγχρονα Ανοικτά Συστήματα Υπερκειμένου βασισμένα σε Ψηφίδες (ΑΣΥ-ΒΨ). Στα πλαίσια της αρχιτεκτονικής της ανακάλυψης υπηρεσιών των ΑΣΥ-ΒΨ μελετήθηκαν οι αρχιτεκτονικές πελάτη/εξυπηρετητή και peer-to-peer. Το άμεσο αποτέλεσμα της συγκεκριμένης προσπάθειας είναι η παροχή στον developer εργαλείου (μηχανισμού) που τον βοηθάει στην αναζήτηση και επισκόπηση υπηρεσιών υπερκειμένου και στην εύκολη επιλογή κατάλληλης υπηρεσίας (με βάση τα χαρακτηριστικά της). Το μελλοντικό αποτέλεσμα της συγκεκριμένης προσπάθειας θα είναι η επίτευξη της γνωστοποίησης των υπηρεσιών που προσφέρουν τα ΑΣΥ-ΒΨ σε όλο και μεγαλύτερο σύνολο από developers με αποτέλεσμα όλο και περισσότερες εφαρμογές να χρησιμοποιούν τις υπηρεσίες των ΑΣΥ-ΒΨ. / In the last few years, Component-Based Open Hypermedia Systems (CB-OHS) have been widely developed with the addition of new hypermedia domains and architectural models for better data organization with main aim to equate and increase the human thinking in this particular field. However, OHS aren’t widely used because they haven’t managed, until this time, to become popular for the advantages that they offer on management, structuring and data linking. Additionally, the OHS community hasn’t yet effectively targeted in the establishment of common methodologies and frameworks that could help any developer to insert hypermedia functionality into his applications. In this Master’s thesis an effort is being made to develop an infrastructure which will help any developer to integrate easily, in his application, hypermedia services. Taking into consideration the above issues, the application of Service Discovery functionality to Component-Based Open Hypermedia Systems was investigated, analyzed and developed, in the context of this project. Trying to specify the architecture that should better fit in this case, two different types of architecture were examined; the client/server and the peer-to-peer architecture. The direct objective of this study is to provide developers with a tool that will help them to search easily and effectively, review and finally choose the proper structure service for them based on each service’s characteristics. A long-term objective of the current research is to make CB-OHS services widely known to developer communities in order to broaden the utilization of the above mentioned services by more and more applications.

In this thesis, we present a hybrid semantic web service discovery framework that exploits both the signatures and specifications of a web service, whilst adopting logical and non-logical service matching methods. For signature level service matching, we have developed two techniques: (i) logical similarity measures applied to the services’ input/output concepts; and (b) non-logical matching based on a Structure Preserving Semantic Matching algorithm. For specification level service matching, we have applied a unique short sentence matching approach on the textual-description of a web service. We evaluated the performance of our S5 Web Service Matchmaker using the OWLS-TC dataset, and furthermore compared its performance with the OWLS-MX discovery model. Our results indicate that S5 Web Service Matchmaker offers an improved web service matching performance with a significant increase in recall and subtle improvements in precision. / Web services are independent software systems designed to offer machine-to-machine interactions over the WWW to achieve well-described operations. The description of a web service entails (a) a syntactic component detailing the service’s operations and data structures in terms of the Web Services Description Language (WSDL), and (b) a semantic component that offers a semantic description, in terms of an ontology, of the services’ data and operations. Typically, service providers expose their services to the public by providing brief descriptions of the service’s operations; the challenge is to discover the right service based on rather sparse service descriptions in response to a specific service request. In this thesis, we present a hybrid semantic web service discovery framework that offer semantic web service discovery at both the signature and specification levels of a web service, whilst exploiting logical and non-logical service matching methods. For signature level service matching, we have developed two techniques: (i) logical similarity measures applied to the services’ input/output concepts; and (b) non-logical matching based on a Structure Preserving Semantic Matching algorithm. For specification level service matching, we have applied a unique short sentence matching approach on the textual-description of a web service. The cumulative similarly measures determine the overall similarity of a services’ description with the service request. We evaluated the performance of our S5 Web Service Matchmaker using the OWLS-TC dataset, and furthermore compared its performance with the OWLS-MX discovery model. Our results indicate that S5 Web Service Matchmaker offers an improved web service matching performance with a significant increase in recall and subtle improvements in precision.

This thesis covers design and implementation of a media system solution for home networks with personal computers and a set-top box. In a home there are effectively two independent media systems with the same purpose: the personal computer and the digital set-top box, with the purpose of delivering digital media in form of audio and video to the consumer. The goal of the thesis work was to implement a solution that bridges the gap between the two systems, so that the user, from the set-top box, can play back media that is actually stored on one or several personal computers. Our solution is based on UPnP technology, which is used for service discovery and control. The choice of UPnP is motivated by an evaluation of discovery protocols, which concludes that UPnP is the most suitable technology in this particular system. Also, an evaluation of suitable transport protocols was done. Here,HTTP was used. For the personal computer, a media server and a graphical user interface for configuring the media server were created. For the set-top box, a media client, and a graphical user interface for browsing the content of the media server, were created. In conclusion, the creation of the prototype was successful and the set-top box was able to playback media that had been shared by the PC on the network.

No description available.

The vision of the Semantic Web aims at enhancing today's Web in order to provide a more efficient and reliable environment for both providers and consumers of Web resources (i.e. information and services). To deploy the Semantic Web, various technologies have been developed, such as machine understandable description languages, language parsers, goal matchers, and resource composition algorithms. Since the Semantic Web is just emerging, each technology tends to make assumptions about different aspects of the Semantic Web's architecture and use, such as the kind of applications that will be deployed, the resource descriptions, the consumers' and providers' requirements, and the existence and capabilities of other technologies. In order to ensure the deployment of a robust and useful Semantic Web and the applications that will rely on it, several aspects of the technologies must be investigated, such as whether the assumptions made are reasonable, whether the existing technologies allow construction of a usable Semantic Web, and the systematic identification of which technology to use when designing new applications. In this thesis we provide a means of investigating these aspects for service discovery, which is a critical task in the context of the Semantic Web. We propose a simulation and evaluation platform for evaluating current and future Semantic Web technology with different resource sets and consumer and provider requirements. For this purpose we provide a model to represent the Semantic Web, a model of the evaluation platform, an implementation of the evaluation platform as a multi-agent system, and an illustrative use of the platform to evaluate some service discovery technology in a travel scenario. The implementation of the platform shows the feasibility of our evaluation approach. We show how the platform provides a controlled setting to support the systematic identification of bottlenecks and other challenges for new Semantic Web applications. Finally, the evaluation shows that the platform can be used to assess technology with respect to both hardware issues such as the kind and number of computers involved in a discovery scenario, and other issues such as the evaluation of the quality of the service discovery result.

Context awareness is an important aspect of pervasive and ubiquitous computing. By utilizing contextual information gathered from the environment, applications can adapt to the user’s specific situation. In this thesis, user context is used to automatically discover multimedia devices and services that can be used by a mobile Session Initiation Protocol (SIP) user agent. The location of the user is captured using various sensing technologies to allow users of our SIP user agent to interact with network attached projectors, speakers, and cameras in a home or office environment. In order to determine the location of the user, we have developed and evaluated a context aggregation framework that gathers and analyzes contextual information from various sources such as passive infrared sensors, infrared beacons, light intensity, and temperature sensors. Once the location of the user is determined, the Service Location Protocol (SLP) is used to search for services. For this purpose, we have implemented a mobile SLP user agent and integrated it with an existing SIP user agent. The resulting mobile SIP user agent is able to dynamically utilize multimedia devices around it without requiring the user to do any manual configuration. This thesis also addressed the challenge of building trust relationship between the user agent and the multimedia services. We propose a mechanism which enables the user agent authenticate service advertisements before starting to redirect media streams. The measurements we have performed indicate that the proposed context aggregation framework provides more accurate location determination when additional sensors are incorporated. Furthermore, the performance measurements indicate that the delay incurred by introducing context awareness to the SIP user agent is acceptable for a small deployment such as home and office environment. In order to realize large scale deployments, future investigations are recommended to further improve the performance of the framework. / Att vara medveten om kontexten är en viktig synpunkt av präglande och allestädes närvarande uppskattning av omgivningen. Genom att utnyttja den kontextuella informationen som samlats in från omgivningen, kan applikationen anpassas till användarens specifika situation. I denna avhandling använder man användarens sammanhang för att automatiskt upptäcka multimedia utrustning och tjänster som kan användas av en mobil Session Initiation Protokoll (SIP) användaragent. Placeringen av användaren mäter man med hjälp av olika sensorer för att låta användare av vår SIP användaragent att interagera med nätverk tillkopplat projektorer, högtalare och kameror i hem eller kontorsmiljöer. För att avgöra var användaren befinner har vi utvecklat och utvärderat en sammanhangsstruktur som samlar in och analyserar innehållsbaserad information från olika källor; passiva infraröda sensorer, infraröd beacons, ljusstyrkan och temperaturgivare. Efter bestämmaning användarens placering den så kallade Service Location Protocol (SLP) användas för att söka efter tjänster. För detta ändamål har vi genomfört en mobil SLP användaragent och integrerat denna med ett befintligt SIP användaragent. Den resulterande i mobil SIP användaragent som dynamiskt kan utnyttja multimedia utrustning runt omkring utan att kräva att användaren skall kunna göra någon manuell konfiguration. Avhandlingen tar även upp den utmaningen som krävs för att bygga förtroende mellan användaragenten och multimedia tjänster. Vi föreslår en mekanism som gör det möjligt för användaragenten att verifiera tjänstannonsering innan man börjar dirigera medieströmmar. Dessutom så indikerar mätningarna av prestanda att fördröjningen som man utsätter den för genom att introducera ”medvetenhet om sammanhanget” till SIP användaragenten är acceptabel på hemma eller i en företagsmiljö. För att stora spridningar skall bli verklighet så rekommenderas det att göra mer forskning för att förbättra prestanda.

L'objectif de cette thèse est de fournir des mécanismes améliorés pour déployer des services compétitifs par des manières rapides et rentables. Nous proposons un modèle de composition de service basé sur un environnement IMS/Web convergent. Ce modèle permet aux utilisateurs non professionnels de réutiliser les services existants pour créer de nouveaux services facilement. Pour améliorer la fonctionnalité de composition automatique, trois stratégies, y compris mise à jour passive, mise à jour active et mise à jour hybride sont proposées et analysées. Nous introduisons ensuite une plateforme centralisée d'exposition de service pour une variété de services, y compris services de Télécom / Web / appareil / services générés par les utilisateurs. Cette plateforme vise à renforcer les caractéristiques de centrée-sur-utilisateur et convergence, et fournir l'accès unifié à différents services. Par la suite, deux modèles basés sur le P2P sont conçus pour compléter le modèle centralisé: i) Un modèle hiérarchique basé sur Chord pour garantir l'efficacité de la découverte de services. Il adopte le concept de publication et découverte de service abstrait pour permettre à la recherche de service ambiguë. ii) Un modèle de superposition-triplex et P2P basé, qui cible principalement des services offerts par les appareils. Dans ce modèle, nous utilisons des passerelles pour déléguer des appareils résidant en eux pour l'exposition globale de services, et utilisons une architecture basée sur une superposition triplex, qui comprend une couche P2P non structurée, une couche de réseau sémantique (SON), et une couche de dépendance de service, pour la partage de l'information de service et la découverte de services / The goal of this thesis is to provide enhanced mechanisms to deploy competitive services in a rapid and cost-effective manner. To achieve this goal, we first propose an automatic service composition model relying on an IMS/Web converged environment. This service composition model is intended to be one in which even non-professional users can easily reuse existing services to create new services. To further improve the automatic service composition feature, three strategies including passive update, active update and hybrid update are proposed and analyzed. We then propose a centralized service exposure framework for a variey of services, including Telecom / Web / Device / user-generated services. This framework aims at enhancing the user-centric and convergence features, and providing the unified access to diverse services.Subsequently, two P2P based service information sharing models are designed to complement the centralized service exposure model : i) A hierarchical P2P based model, which reuses Chord for guaranteeing the service discovery efficiency, meanwhile adopts the concept of abstract service publication and discovery for enabling the ambiguous services searching. ii) A triplex P2P overlay based model, which mainly targets the devices offered services. In this model, we use the gateways to delegate the devices residing in them for the global service exposure, and use a triplex overlay based architecture, which includes an underlying unstructured P2P layer, a Semantic Overlay Network (SON) based overlay and a service dependency overlay, for the service information sharing and discovery