- About
-
The Global ETD Search service is a free service for researchers
to find electronic theses and dissertations. This service is
provided by the
Networked Digital Library of Theses and Dissertations.
Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
Search results
Showing 31 to 32 of 32 (0.034 seconds)Spelling suggestions: "subject:"metadata"" "subject:"metatdata""
| 31 |
Distribution multi-contenus sur Internet / Content distribution over InternetMnie Filali, Imane 27 September 2016 (has links)
Dans cette thèse, nous nous sommes intéressés aux protocoles pair-à-pair (P2P), qui représentent une solution prometteuse pour la diffusion et le partage de données à faible coût sur Internet. Nous avons mené, dans un premier temps, une étude comportementale de différents protocoles P2P pour le partage de fichier (distribution de contenus sans contrainte de temps) puis le live. Dans la première étude centréesur le partage de fichier, nous avons montré l’impact d’Hadopi sur le comportement des utilisateurs et discuté l’efficacité des protocoles en fonction du contenu et l’efficacité protocolaire, en se basant sur les choix des utilisateurs. BitTorrent s’est nettement démarqué au cours de cette étude, notamment pour les grands contenus. En ce qui concerne le live, nous nous sommes intéressés à la qualité de servicedu réseau de distribution live Sopcast, car plus de 60% des événements live diffusés en P2P le sont sur ce réseau. Notre analyse approfondie de ces deux modes de distribution nous a fait nous recentrer sur BitTorrent, qui est à la base de tous les protocoles P2P Live, et est efficace en partage de fichier et complètement open source. Dans la seconde partie de la thèse, nous avons proposé et implémenté dansun environnement contrôlé un nouveau protocole sur la base de BitTorrent avec des mécanismes protocolaires impliquant tous les pairs dans la gestion du réseau. Ces nouveaux mécanismes permettent d’augmenter l’efficacité du protocole via une meilleure diffusion, tant pour le live que le partage de fichier, de métadonnées (la pièce la plus rare) et via une méthode dite de push, par laquelle un client va envoyer du contenu aux pairs les plus dans le besoin / In this study, we focused on peer-to-peer protocols (P2P), which represent a promising solution for data dissemination and content delivery at low-cost in the Internet. We performed, initially, a behavioral study of various P2P protocols for file sharing (content distribution without time constraint) and live streaming. Concerning file sharing, we have shown the impact of Hadopi on users’ behavior and discussed the effectiveness of protocols according to content type, based on users’ choice. BitTorrent appeared as the most efficient approach during our study, especially when it comes to large content. As for streaming, we studied the quality of service of Sopcast, a live distribution network that accounts for more than 60% of P2P broadcast live events. Our in-depth analysis of these two distributionmodes led us to focus on the BitTorrent protocol because of its proven efficiency in file sharing and the fact that it is open source. In the second part of the thesis, we proposed and implemented a new protocol based on BitTorrent, in a controlled environment. The modifications that we proposed allow to increase the efficiency of the protocol through improved dissemination of metadata (the rarest piece), both for live and file sharing. An enhanced version is introduced with a push method, where nodes that lag behind receive an extra service so as to improve the overall performance
|
| 32 |
Vision Beyond Optics: Standardization, Evaluation and Innovation for Fluorescence Microscopy in Life SciencesHuisman, Maximiliaan 01 April 2019 (has links)
Fluorescence microscopy is an essential tool in biomedical sciences that allows specific molecules to be visualized in the complex and crowded environment of cells. The continuous introduction of new imaging techniques makes microscopes more powerful and versatile, but there is more than meets the eye. In addition to develop- ing new methods, we can work towards getting the most out of existing data and technologies. By harnessing unused potential, this work aims to increase the richness, reliability, and power of fluorescence microscopy data in three key ways: through standardization, evaluation and innovation.
A universal standard makes it easier to assess, compare and analyze imaging data – from the level of a single laboratory to the broader life sciences community. We propose a data-standard for fluorescence microscopy that can increase the confidence in experimental results, facilitate the exchange of data, and maximize compatibility with current and future data analysis techniques.
Cutting-edge imaging technologies often rely on sophisticated hardware and multi-layered algorithms for reconstruction and analysis. Consequently, the trustworthiness of new methods can be difficult to assess. To evaluate the reliability and limitations of complex methods, quantitative analyses – such as the one present here for the 3D SPEED method – are paramount.
The limited resolution of optical microscopes prevents direct observation of macro- molecules like DNA and RNA. We present a multi-color, achromatic, cryogenic fluorescence microscope that has the potential to produce multi-color images with sub-nanometer precision. This innovation would move fluorescence imaging beyond the limitations of optics and into the world of molecular resolution.
|
Page generated in 0.0386 seconds