Tesis doctoral de Bernardo Antonio De La Ossa Pérez
This dissertation studies the prefetching technique applied to the world wide web from a realistic and practical point of view. Web prefetching is a technique to reduce he user perceived latency by predicting and pre-processing next user accesses. until now the open research literature about web prefetching has focused on theoretical questions and has not taken into account some of the problems that arise when implementing the technique in real conditions. Furthermore, previous works have used simplified models for evaluation that do not consider how practical issues really affect the implementation of a prefetching technique. Moreover, only few works have considered performance indexes that are relevant to users when evaluating the benefits that prefetching can achieve. in order to overcome these three limitations, we developed delfos, a web prefetching framework that implements web prediction and prefetching in a real environment, and can be integrated into the web architecture without modifying the standard web protocols and in a compatible way with the existing software products. Delfos can also be used to evaluate and compare existing prefetching techniques and algorithms and to assist in the design of new ones because it provides detailed statistics reports. As an example, delfos is used to propose, test and evaluate a new technique (predict at prefetch, pap) able to considerably reduce the user perceived latency with no additional cost compared to the basic prefetch mechanism. the prediction algorithms proposed in the research literature that achieve the highest precision involve a high computational cost, which is an important drawback for including them in real systems. To deal with this disadvantage, a novel low-cost web prediction algorithm (referrer graph, rg) is proposed in this phd dissertation. This algorithm learns from users accesses and builds a markov model that can distinguish between dependencies in objects of the same page and objects of different pages by using the object uri and the referrer in each request. Rg includes a prune mechanism that controls the computational resource consumption while sustaining the performance. this dissertation also includes an empirical study to investigate the maximum benefits that web users can expect from prefetching techniques in the current web. Unlike previous theoretical studies, this work considers a realistic prefetching architecture using real and representative traces. In this way, the influence of real implementation constraints are considered and analyzed. The results obtained show that web prefetching can improve page latency up to 52% in the studied traces, which encourages researchers to focus future works on this direction.
Datos académicos de la tesis doctoral «Web prefetching techniques in real environments«
- Título de la tesis: Web prefetching techniques in real environments
- Autor: Bernardo Antonio De La Ossa Pérez
- Universidad: Politécnica de Valencia
- Fecha de lectura de la tesis: 31/03/2011
Dirección y tribunal
- Director de la tesis
- Ana Pont Sanjuán
- Tribunal
- Presidente del tribunal: pietro Manzoni
- ramón Puigjaner trepat (vocal)
- Miguel Lozano ibañez (vocal)
- ramon Caceres rodriguez (vocal)