35,330 research outputs found
Peer to Peer Information Retrieval: An Overview
Peer-to-peer technology is widely used for file sharing. In the past decade a number of prototype peer-to-peer information retrieval systems have been developed. Unfortunately, none of these have seen widespread real- world adoption and thus, in contrast with file sharing, information retrieval is still dominated by centralised solutions. In this paper we provide an overview of the key challenges for peer-to-peer information retrieval and the work done so far. We want to stimulate and inspire further research to overcome these challenges. This will open the door to the development and large-scale deployment of real-world peer-to-peer information retrieval systems that rival existing centralised client-server solutions in terms of scalability, performance, user satisfaction and freedom
Query-Based Sampling using Snippets
Query-based sampling is a commonly used approach to model the content of servers. Conventionally, queries are sent to a server and the documents in the search results returned are downloaded in full as representation of the server’s content. We present an approach that uses the document snippets in the search results as samples instead of downloading the entire documents. We show this yields equal or better modeling performance for the same bandwidth consumption depending on collection characteristics, like document length distribution and homogeneity. Query-based sampling using snippets is a useful approach for real-world systems, since it requires no extra operations beyond exchanging queries and search results
An Optimal Trade-off between Content Freshness and Refresh Cost
Caching is an effective mechanism for reducing bandwidth usage and
alleviating server load. However, the use of caching entails a compromise
between content freshness and refresh cost. An excessive refresh allows a high
degree of content freshness at a greater cost of system resource. Conversely, a
deficient refresh inhibits content freshness but saves the cost of resource
usages. To address the freshness-cost problem, we formulate the refresh
scheduling problem with a generic cost model and use this cost model to
determine an optimal refresh frequency that gives the best tradeoff between
refresh cost and content freshness. We prove the existence and uniqueness of an
optimal refresh frequency under the assumptions that the arrival of content
update is Poisson and the age-related cost monotonically increases with
decreasing freshness. In addition, we provide an analytic comparison of system
performance under fixed refresh scheduling and random refresh scheduling,
showing that with the same average refresh frequency two refresh schedulings
are mathematically equivalent in terms of the long-run average cost
A user perspective of quality of service in m-commerce
This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2004 Springer VerlagIn an m-commerce setting, the underlying communication system will have to provide a Quality of Service (QoS) in the presence of two competing factors—network bandwidth and, as the pressure to add value to the business-to-consumer (B2C) shopping experience by integrating multimedia applications grows, increasing data sizes. In this paper, developments in the area of QoS-dependent multimedia perceptual quality are reviewed and are integrated with recent work focusing on QoS for e-commerce. Based on previously identified user perceptual tolerance to varying multimedia QoS, we show that enhancing the m-commerce B2C user experience with multimedia, far from being an idealised scenario, is in fact feasible if perceptual considerations are employed
Query-Based Sampling using Only Snippets
Query-based sampling is a popular approach to model the content of an uncooperative server. It works by sending queries to the server and downloading the returned documents in the search results in full. This sample of documents then represents the server’s content. We present an approach that uses the document snippets as samples instead of downloading entire documents. This yields more stable results at the same amount of bandwidth usage as the full document approach. Additionally, we show that using snippets does not necessarily incur more latency, but can actually save time
The Effect of Network and Infrastructural Variables on SPDY's Performance
HTTP is a successful Internet technology on top of which a lot of the web
resides. However, limitations with its current specification, i.e. HTTP/1.1,
have encouraged some to look for the next generation of HTTP. In SPDY, Google
has come up with such a proposal that has growing community acceptance,
especially after being adopted by the IETF HTTPbis-WG as the basis for
HTTP/2.0. SPDY has the potential to greatly improve web experience with little
deployment overhead. However, we still lack an understanding of its true
potential in different environments. This paper seeks to resolve these issues,
offering a comprehensive evaluation of SPDY's performance using extensive
experiments. We identify the impact of network characteristics and website
infrastructure on SPDY's potential page loading benefits, finding that these
factors are decisive for SPDY and its optimal deployment strategy. Through
this, we feed into the wider debate regarding HTTP/2.0, exploring the key
aspects that impact the performance of this future protocol
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