Proxy caching is a key technique to reduce transmission cost for on-demand multimedia streaming. The
effectiveness of current caching schemes, however, is limited by the insufcient storage space and weak cooperations
among proxies and their clients, particularly considering the high bandwidth demands from media objects. In this
paper, we propose COPACC, a cooperative proxy-and-client caching system that addresses the above deciencies.
This innovative approach combines the advantages of both proxy caching and peer-to-peer client communications.
It leverages the client-side caching to amplify the aggregated cache space and rely on dedicated proxies to
effectively coordinate the communications. We propose a comprehensive suite of distributed protocols to facilitate
the interactions among different network entities in COPACC. It also realizes a smart and cost-effective cache
indexing, searching, and verifying scheme. Furthermore, we develop an efcient cache allocation algorithm for
distributing video segments among the proxies and clients. The algorithm not only minimizes the aggregated
transmission cost of the whole system, but also accommodates heterogeneous computation and storage constraints
of proxies and clients. We have extensively evaluated the performance of COPACC under various network and endsystem
congurations. The results demonstrate that it achieves remarkably lower transmission cost as compared to
pure proxy-based caching with limited storage space. On the other hand, it is much more robust than a pure peerto-
peer communication system in the presence of node failures. Meanwhile, its computation and control overheads
are both kept in low levels.
Keywords: Media Streaming, Proxy caching, Peer-to-Peer caching, Media segmentat ion and Resource allocation
I. Introduction
For the past few years, we have witnessed the increasingly used streaming multimedia trafc on the
Internet, and on-demand streaming for clients of asynchronous playback requests is amongst the most
popular networked media services. Given its broad spectrum of applications, like NetTV and distance
Alan
Wednesday, April 8, 2009
Tuesday, March 3, 2009
Monday, February 23, 2009
FIR
The concept “textual entailment” is a new approach that is applied in the natural language processing field. It is used to indicate the state in which the semantics of one natural language written text can be inferred from the semantics of another text. Specifically, if the truth of a text segment entails the truth of another text segment. For example, given the texts:
1. For their discovery of ulcer-causing bacteria, Australian doctors Robin Warren and Barry Marshall have received the 2005 Nobel Prize in Physiology or Medicine.
2. Robin Warren was awarded a Nobel Prize.
1. For their discovery of ulcer-causing bacteria, Australian doctors Robin Warren and Barry Marshall have received the 2005 Nobel Prize in Physiology or Medicine.
2. Robin Warren was awarded a Nobel Prize.
Sunday, February 22, 2009
P2P Web Search Engine.
ABSTRACT
The fast development of the World Wide Web and Dynamic nature makes it a challenge for searching and retrieving of information that is more recent. The WWW is a rapidly growing and changing information source. Its growth and change rates make the task of finding recent information harder.
The exponentially growing information published on the Web relies largely on a few major search engines like Google to be brought to the public nowadays. However, such an engine is not suitable for fresh information retrieval because it spends a long time to collect web pages by using a web robot (or crawler).
In the other hand, there are some distributed search engines such as Cooperative Search Engine (CSE), and so on. However, these distributed search engines are able to update in a very short time, e.g. a few minutes. But it has more communication delay.
In this project, in order to reduce the delay we proposed a P2P Web search that connects an a-priori unlimited number of peers, each of which maintains a personal local database and a local search facility.
Each peer posts a small amount of metadata to a physically distributed directory layered on top of a DHT-based overlay network that is used to efficiently select promising peers from across the peer population that can best locally execute a query.
Further, usage of Textual Entailment approach helps in searching the recent document for a given keyword.
The fast development of the World Wide Web and Dynamic nature makes it a challenge for searching and retrieving of information that is more recent. The WWW is a rapidly growing and changing information source. Its growth and change rates make the task of finding recent information harder.
The exponentially growing information published on the Web relies largely on a few major search engines like Google to be brought to the public nowadays. However, such an engine is not suitable for fresh information retrieval because it spends a long time to collect web pages by using a web robot (or crawler).
In the other hand, there are some distributed search engines such as Cooperative Search Engine (CSE), and so on. However, these distributed search engines are able to update in a very short time, e.g. a few minutes. But it has more communication delay.
In this project, in order to reduce the delay we proposed a P2P Web search that connects an a-priori unlimited number of peers, each of which maintains a personal local database and a local search facility.
Each peer posts a small amount of metadata to a physically distributed directory layered on top of a DHT-based overlay network that is used to efficiently select promising peers from across the peer population that can best locally execute a query.
Further, usage of Textual Entailment approach helps in searching the recent document for a given keyword.
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