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Identifier

uch.csd.msc//1996petsagourakis

Title

Ένα Σύστημα Αποδοτικής Μεταφοράς www Πληροφορίας βασισμένο σε προτιμήσεις του χρήστη και στην Εκτίμηση της Κατάστασης του Δικτύου

Alternative Title

A System for Efficient Transfer of WWW Information based on User Preferences and Network Status Estimation

Creator

Petsaggourakis, Emmanouel

Contributor

Κ. Κουρκουμπέτης

Abstract

World Wide Web (WWW) is the most common and faster evolved computer application nowadays. One of it's weaknesses is the lack of knowledge about the conditions that exists on the underlining network. So, it cannot adapt it's behavior appropriately, causing or contributing in congestion. Also HTTP, the protocol of WWW, has some inherent inefficiencies which add unnecessary delay on documents transfer. The above items results in a degradation of performance offered to the end users. The present work deals with both of these issues. The system we designed and implemented uses a modified WWW client and server. In addition a process that estimates network parameters (delay, packet loss, throughput) cooperates with the WWW server. The knowledge of network status is used for the selection of the ``best'' among different types of the same information. The selection depends not only on network status but also on user preferences. For that reason we define the notion of user profile. This allows users to order their preference for the format of the document they wish to retrieve (e.g. video, audio, text), including time constrains. We extend the HTTP protocol enabling the WWW client to communicate it to server. A case study with various scenarios of network activity and information of multiple types, showed that our system responds properly on user demands and constrains. Further more in the HTTP protocol we replaced the technique of one connection per request, with persistent connections. In this way, many HTTP requests/responses can be passed over the same connection, avoiding the overhead and latency caused by multiple connections setups. The measurements we have got with representative WWW pages (in size and number of inline images), showed a significant improvement of HTTP performance.

Subject

WWW, HTTP, preferences, performance, user profile, network status

α) Δίκτυα Υπολογιστών και Ψηφιακές Επικοινωνίες, β) Παράλληλα και Κατανεμημένα Συστήματα

Issue date

1996-11-01

Date available

1997-06-2

Collection

School/Department--School of Sciences and Engineering--Department of Computer Science--Post-graduate theses

Type of Work--Post-graduate theses

Permanent Link

https://elocus.lib.uoc.gr//dlib/5/6/d/metadata-dlib-1996petsagourakis.tkl