10,293 research outputs found
Building a flexible web caching system.
Web caching is a technology that has demonstrated to
improve traffic on the Internet. To find out how to
implement a Web caching architecture that assures
improvements is not an easy task. The problem is more
difficult when we are interested in deploying a distributed
and cooperative Web caching system. We have found that
some cooperative Web caching architectures could be
unviable when changes on the network environment
appear. This situation suggests that a cooperative Web
caching system could get worst access to Web objects.
However in this paper we present an architecture that
combines the best of several Web caching configurations
that we have previously analyzed. Our architecture gives
basic ideas for implementing a cooperative Web caching
system using groups of HTTP proxy servers which can
improve access to remote Web objects regardless of the
changes that might occur on the network environment
(changes that could produce modifications in Web object
validation policies and/or types of caching
communication).Peer Reviewe
Harvest: An Integrated Set of Tools for a Digital Library
This paper discusses the problems in organization and retrieval due
proliferation resources in digital format over the web. It presents the
harvest systems which tackles the problems through a set of
customizable tools for gathering information from diverse
repositories, building topic specific content indexes, flexibly
searching indexes, widely replicating them, and caching objects as
they are retrieved across the Internet. Harvest permits flexible
construction of information services that use both the network and
information servers efficiently. It is easily configurable system and
can be deployed to automatically collect and summarize related
objects from around the Internet into digital library collections
Staging Transformations for Multimodal Web Interaction Management
Multimodal interfaces are becoming increasingly ubiquitous with the advent of
mobile devices, accessibility considerations, and novel software technologies
that combine diverse interaction media. In addition to improving access and
delivery capabilities, such interfaces enable flexible and personalized dialogs
with websites, much like a conversation between humans. In this paper, we
present a software framework for multimodal web interaction management that
supports mixed-initiative dialogs between users and websites. A
mixed-initiative dialog is one where the user and the website take turns
changing the flow of interaction. The framework supports the functional
specification and realization of such dialogs using staging transformations --
a theory for representing and reasoning about dialogs based on partial input.
It supports multiple interaction interfaces, and offers sessioning, caching,
and co-ordination functions through the use of an interaction manager. Two case
studies are presented to illustrate the promise of this approach.Comment: Describes framework and software architecture for multimodal web
interaction managemen
Temporal Locality in Today's Content Caching: Why it Matters and How to Model it
The dimensioning of caching systems represents a difficult task in the design
of infrastructures for content distribution in the current Internet. This paper
addresses the problem of defining a realistic arrival process for the content
requests generated by users, due its critical importance for both analytical
and simulative evaluations of the performance of caching systems. First, with
the aid of YouTube traces collected inside operational residential networks, we
identify the characteristics of real traffic that need to be considered or can
be safely neglected in order to accurately predict the performance of a cache.
Second, we propose a new parsimonious traffic model, named the Shot Noise Model
(SNM), that enables users to natively capture the dynamics of content
popularity, whilst still being sufficiently simple to be employed effectively
for both analytical and scalable simulative studies of caching systems.
Finally, our results show that the SNM presents a much better solution to
account for the temporal locality observed in real traffic compared to existing
approaches.Comment: 7 pages, 7 figures, Accepted for publication in ACM Computer
Communication Revie
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
Document Archiving, Replication and Migration Container for Mobile Web Users
With the increasing use of mobile workstations for a wide variety of tasks
and associated information needs, and with many variations of available
networks, access to data becomes a prime consideration. This paper discusses
issues of workstation mobility and proposes a solution wherein the data
structures are accessed in an encapsulated form - through the Portable File
System (PFS) wrapper. The paper discusses an implementation of the Portable
File System, highlighting the architecture and commenting upon performance of
an experimental system. Although investigations have been focused upon mobile
access of WWW documents, this technique could be applied to any mobile data
access situation.Comment: 5 page
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