Transmission adaptative de modèles 3D massifs

Avec les progrès de l'édition de modèles 3D et des techniques de reconstruction 3D, de plus en plus de modèles 3D sont disponibles et leur qualité augmente. De plus, le support de la visualisation 3D sur le web s'est standardisé ces dernières années. Un défi majeur est donc de transmettre des modèles massifs à distance et de permettre aux utilisateurs de visualiser et de naviguer dans ces environnements virtuels. Cette thèse porte sur la transmission et l'interaction de contenus 3D et propose trois contributions majeures. Tout d'abord, nous développons une interface de navigation dans une scène 3D avec des signets -- de petits objets virtuels ajoutés à la scène sur lesquels l'utilisateur peut cliquer pour atteindre facilement un emplacement recommandé. Nous décrivons une étude d'utilisateurs où les participants naviguent dans des scènes 3D avec ou sans signets. Nous montrons que les utilisateurs naviguent (et accomplissent une tâche donnée) plus rapidement en utilisant des signets. Cependant, cette navigation plus rapide a un inconvénient sur les performances de la transmission : un utilisateur qui se déplace plus rapidement dans une scène a besoin de capacités de transmission plus élevées afin de bénéficier de la même qualité de service. Cet inconvénient peut être atténué par le fait que les positions des signets sont connues à l'avance : en ordonnant les faces du modèle 3D en fonction de leur visibilité depuis un signet, on optimise la transmission et donc, on diminue la latence lorsque les utilisateurs cliquent sur les signets. Deuxièmement, nous proposons une adaptation du standard de transmission DASH (Dynamic Adaptive Streaming over HTTP), très utilisé en vidéo, à la transmission de maillages texturés 3D. Pour ce faire, nous divisons la scène en un arbre k-d où chaque cellule correspond à un adaptation set DASH. Chaque cellule est en outre divisée en segments DASH d'un nombre fixe de faces, regroupant des faces de surfaces comparables. Chaque texture est indexée dans son propre adaptation set à différentes résolutions. Toutes les métadonnées (les cellules de l'arbre k-d, les résolutions des textures, etc.) sont référencées dans un fichier XML utilisé par DASH pour indexer le contenu: le MPD (Media Presentation Description). Ainsi, notre framework hérite de la scalabilité offerte par DASH. Nous proposons ensuite des algorithmes capables d'évaluer l'utilité de chaque segment de données en fonction du point de vue du client, et des politiques de transmission qui décident des segments à télécharger. Enfin, nous étudions la mise en place de la transmission et de la navigation 3D sur les appareils mobiles. Nous intégrons des signets dans notre version 3D de DASH et proposons une version améliorée de notre client DASH qui bénéficie des signets. Une étude sur les utilisateurs montre qu'avec notre politique de chargement adaptée aux signets, les signets sont plus susceptibles d'être cliqués, ce qui améliore à la fois la qualité de service et la qualité d'expérience des utilisateur

Supporting Non-Linear and Non-Continuous Media Access in Peer-to-Peer Multimedia Systems

Ph.DDOCTOR OF PHILOSOPH

A Social Dimension for Digital Architectural Practice

Merged with duplicate record 10026.1/1296 on 14.03.2017 by CS (TIS)This thesis proceeds from an analysis of practice and critical commentary to claim that the opportunities presented to some architectural practices by the advent of ubiquitous digital technology have not been properly exploited. The missed opportunities, it claims, can be attributed largely to the retention of a model of time and spaces as discrete design parameters, which is inappropriate in the context of the widening awareness of social interconnectedness that digital technology has also facilitated. As a remedy, the thesis shows that some social considerations essential to good architecture - which could have been more fully integrated in practice and theory more than a decade ago - can now be usefully revisited through a systematic reflection on an emerging use of web technologies that support social navigation. The thesis argues through its text and a number of practical projects that the increasing confidence and sophistication of interdisciplinary studies in geography, most notably in human geography, combined with the technological opportunities of social navigation, provide a useful model of time and space as a unified design parameter. In so doing the thesis suggests new possibilities for architectural practices involving social interaction. Through a literature review of the introduction and development of digital technologies to architectural practice, the thesis identifies the inappropriate persistence of a number of overarching concepts informing architectural practice. In a review of the emergence and growth of 'human geography' it elaborates on the concept of the social production of space, which it relates to an analysis of emerging social navigation technologies. In so doing the thesis prepares the way for an integration of socially aware architecture with the opportunities offered by social computing. To substantiate its claim the thesis includes a number of practical public projects that have been specifically designed to extend and amplify certain concepts, along with a large-scale design project and systematic analysis which is intended to illustrate the theoretical claim and provide a model for further practical exploitation

The design of 3D cyberspace as user interface: Advantages and limitations

Virtual reality propagandists, technologists and the Internet community have long debated the issue of the usability of online three-dimensional (3D) environments. A lot of work was published about the benefits of 3D spaces for human-computer interaction and information visualisation due to their realism (Anders, Kalawsky, Crossley, Davies, McGrath, Rejman-Greene, 1998, Hamit, 1993, Heim, 1992, Aukstakalnis, Blatner, Roth, 1992). This topic also receives continuous industry support including standardisation of Virtual Reality Modeling Language ( VRML, VRML Consortium, 1997) and the more recent Macromedia & Intel alliance to bring web 3D to the mainstream (200 1, Intel Corporation). The actual implementation of this technology is, however, still challenging (McCarthy & Descartes, 1998) and minimal because 3D is too new and waiting for good design to be discovered (Nielsen, 1998). The practical aim of this project is to fulfil the niche by creating a functional 3D interface for the access of two-dimensional (2D) information, such as text, using VRML. The theoretical aim is to contribute to further research into 3D usability by describing and analysing the design process in terms of possibilities, challenges and limitations

Microsoft Ecosystem

Mobile technology landscape has changed drastically in recent times. The change is due to the merging of mobile systems with the Internet and the Web. Mobile devices functions expanded much beyond their traditional use and became part of bigger systems. These systems have been given name ecosystems by using analogy with biological ecosystems. Mobile ecosystems are characterized by integration of devices, applications and services creating a dynamic, living business system. Ecosystem attracts large number of independent application and service developers who can develop and sell their products using application stores. Ecosystem owners provide strategic tools and services which are quickly evolving. This creates very strong drive for innovation in the ecosystem and attracts huge number of users who are willing to pay for new applications and services. Ecosystem owners get huge profits from advertising and profiling the users. This makes mobile ecosystem alive and expanding. There are two existing mobile ecosystems created by Apple and Google which became huge success. This has undermined position of Nokia in the mobile world and challenged the role of Microsoft in the information technology world. In this thesis we analyze efforts of Microsoft to create another mobile ecosystem in which Nokia could play major role. Apple and Google ecosystems are described and evaluated in detail. Components of Microsoft platform are described next and compared with Apple and Google. Challenges for Microsoft to create its own ecosystem are analyzed and conclusions are formulated

CHORUS Deliverable 2.2: Second report - identification of multi-disciplinary key issues for gap analysis toward EU multimedia search engines roadmap

After addressing the state-of-the-art during the first year of Chorus and establishing the existing landscape in multimedia search engines, we have identified and analyzed gaps within European research effort during our second year. In this period we focused on three directions, notably technological issues, user-centred issues and use-cases and socio- economic and legal aspects. These were assessed by two central studies: firstly, a concerted vision of functional breakdown of generic multimedia search engine, and secondly, a representative use-cases descriptions with the related discussion on requirement for technological challenges. Both studies have been carried out in cooperation and consultation with the community at large through EC concertation meetings (multimedia search engines cluster), several meetings with our Think-Tank, presentations in international conferences, and surveys addressed to EU projects coordinators as well as National initiatives coordinators. Based on the obtained feedback we identified two types of gaps, namely core technological gaps that involve research challenges, and “enablers”, which are not necessarily technical research challenges, but have impact on innovation progress. New socio-economic trends are presented as well as emerging legal challenges

DIVE on the internet

This dissertation reports research and development of a platform for Collaborative Virtual Environments (CVEs). It has particularly focused on two major challenges: supporting the rapid development of scalable applications and easing their deployment on the Internet. This work employs a research method based on prototyping and refinement and promotes the use of this method for application development. A number of the solutions herein are in line with other CVE systems. One of the strengths of this work consists in a global approach to the issues raised by CVEs and the recognition that such complex problems are best tackled using a multi-disciplinary approach that understands both user and system requirements. CVE application deployment is aided by an overlay network that is able to complement any IP multicast infrastructure in place. Apart from complementing a weakly deployed worldwide multicast, this infrastructure provides for a certain degree of introspection, remote controlling and visualisation. As such, it forms an important aid in assessing the scalability of running applications. This scalability is further facilitated by specialised object distribution algorithms and an open framework for the implementation of novel partitioning techniques. CVE application development is eased by a scripting language, which enables rapid development and favours experimentation. This scripting language interfaces many aspects of the system and enables the prototyping of distribution-related components as well as user interfaces. It is the key construct of a distributed environment to which components, written in different languages, connect and onto which they operate in a network abstracted manner. The solutions proposed are exemplified and strengthened by three collaborative applications. The Dive room system is a virtual environment modelled after the room metaphor and supporting asynchronous and synchronous cooperative work. WebPath is a companion application to a Web browser that seeks to make the current history of page visits more visible and usable. Finally, the London travel demonstrator supports travellers by providing an environment where they can explore the city, utilise group collaboration facilities, rehearse particular journeys and access tourist information data

AXMEDIS 2007 Conference Proceedings

The AXMEDIS International Conference series has been established since 2005 and is focused on the research, developments and applications in the cross-media domain, exploring innovative technologies to meet the challenges of the sector. AXMEDIS2007 deals with all subjects and topics related to cross-media and digital-media content production, processing, management, standards, representation, sharing, interoperability, protection and rights management. It addresses the latest developments and future trends of the technologies and their applications, their impact and exploitation within academic, business and industrial communities