2,710 research outputs found
Document expansion for image retrieval
Successful information retrieval requires eïżœective matching
between the user's search request and the contents of relevant
documents. Often the request entered by a user may
not use the same topic relevant terms as the authors' of the
documents. One potential approach to address problems
of query-document term mismatch is document expansion
to include additional topically relevant indexing terms in a
document which may encourage its retrieval when relevant
to queries which do not match its original contents well. We
propose and evaluate a new document expansion method
using external resources. While results of previous research
have been inconclusive in determining the impact of document
expansion on retrieval eïżœectiveness, our method is
shown to work eïżœectively for text-based image retrieval of
short image annotation documents. Our approach uses the
Okapi query expansion algorithm as a method for document
expansion. We further show improved performance can be
achieved by using a \document reduction" approach to include
only the signiïżœcant terms in a document in the expansion
process. Our experiments on the WikipediaMM task at
ImageCLEF 2008 show an increase of 16.5% in mean average
precision (MAP) compared to a variation of Okapi BM25 retrieval
model. To compare document expansion with query
expansion, we also test query expansion from an external resource
which leads an improvement by 9.84% in MAP over
our baseline. Our conclusion is that the document expansion
with document reduction and in combination with query expansion
produces the overall best retrieval results for shortlength
document retrieval. For this image retrieval task, we
also concluded that query expansion from external resource
does not outperform the document expansion method
Applying digital content management to support localisation
The retrieval and presentation of digital content such as that on the World Wide Web (WWW) is a substantial area of research. While recent years have seen huge expansion in the size of web-based archives that can be searched efficiently by commercial search engines, the presentation of potentially relevant content is still limited to ranked document lists represented by simple text snippets or image keyframe surrogates. There is expanding interest in techniques to personalise the presentation of content to improve the richness and effectiveness of the user experience. One of the most significant challenges to achieving this is the increasingly multilingual nature of this data, and the need to provide suitably localised responses to users based on this content. The Digital Content Management (DCM) track of the Centre for Next Generation Localisation (CNGL) is seeking to develop technologies to support advanced personalised access and presentation of information by combining elements from the existing research areas of Adaptive Hypermedia and Information Retrieval. The combination of these technologies is intended to produce significant improvements in the way users access information. We review key features of these technologies and introduce early ideas for how these technologies can support localisation and localised content before concluding with some impressions of future directions in DCM
Identifying common user behaviour in multilingual search logs
The LADS (Log Analysis for Digital Societies) task at CLEF
aims at investigating user actions in a multilingual setting. We carried out an analysis of search logs with the objectives of investigating how users from different linguistic or cultural backgrounds behave in search,
and how the discovery of patterns in user actions could be used for community identification. The findings confirm that users from a different background behave differently, and that there are identifiable patterns in the user actions. The findings suggest that there is scope for further investigation of how search logs can be exploited to personalise and improve cross-language search as well as improve the TEL search system
Multilingual adaptive search for digital libraries
This paper describes a framework for Adaptive Multilingual Information Retrieval (AMIR) which allows multilingual resource discovery and delivery using on-the-ïŹy machine translation of documents and queries. Result documents
are presented to the user in a contextualised manner. Challenges and affordances of both Adaptive and Multilingual IR, with a particular focus on Digital Libraries, are detailed. The framework components are motivated by a series of results from experiments on query logs and documents from The European Library. We conclude that factoring adaptivity and multilinguality aspects into the search process can enhance the userâs experience with online Digital Libraries
Random Networks with given Rich-club Coefficient
In complex networks it is common to model a network or generate a surrogate
network based on the conservation of the network's degree distribution. We
provide an alternative network model based on the conservation of connection
density within a set of nodes. This density is measure by the rich-club
coefficient. We present a method to generate surrogates networks with a given
rich-club coefficient. We show that by choosing a suitable local linking term,
the generated random networks can reproduce the degree distribution and the
mixing pattern of real networks. The method is easy to implement and produces
good models of real networks.Comment: revised version, new figure
Statistical mechanics of triangulated ribbons
We use computer simulations and scaling arguments to investigate statistical
and structural properties of a semiflexible ribbon composed of isosceles
triangles. We study two different models, one where the bending energy is
calculated from the angles between the normal vectors of adjacent triangles,
the second where the edges are viewed as semiflexible polymers so that the
bending energy is related to the angles between the tangent vectors of
next-nearest neighbor triangles. The first model can be solved exactly whereas
the second is more involved. It was recently introduced by Liverpool and
Golestanian Phys.Rev.Lett. 80, 405 (1998), Phys.Rev.E 62, 5488 (2000) as a
model for double-stranded biopolymers such as DNA. Comparing observables such
as the autocorrelation functions of the tangent vectors and the bond-director
field, the probability distribution functions of the end-to-end distance, and
the mean squared twist we confirm the existence of local twist correlation, but
find no indications for other predicted features such as twist-stretch
coupling, kinks, or oscillations in the autocorrelation function of the
bond-director field.Comment: 10 pages, 13 figures. submitted to PRE, revised versio
Detecting the intermediate-mass Higgs boson through the associate production channel pp --> t + anti-t + H + X
We examine the detection of the intermediate-mass Higgs boson (IMH) at LHC
through the associate production channel pp-->t+(anti-t)+H+X-->l+photon+
photon+X'. It is shown that by applying kinematic cuts or b-tagging on the
final state jets, the main backgrounds of W(-->l+nu)+photon+photon+(n-jet) can
be reduced substantially without significant loss of signals. It is possible to
detect the Higgs boson at LHC through the pp-->t+(anti-t)+H+X channel using a
modest photon detector with mass resolution of about 3% of the photon pair
invariant mass.Comment: 10 pages, standard LaTex fil
Electroweak Corrections to the Charged Higgs Boson Decay into Chargino and Neutralino
The electroweak corrections to the partial widths of the decays including one-loop
diagrams of the third generation quarks and squarks, are investigated within
the Supersymmetric Standard Model. The relative corrections can reach the
values about 10%, therefore they should be taken into account for the precise
experimental measurement at future colliders.Comment: 21 pages, 6 eps figures, 1 Latex fil
Associated production of H^{\pm} and W^{\mp} in high-energy e+e- collisions in the Minimal Supersymmetric Standard Model
We study the associated production of the charged Higgs boson and W^{\pm}
gauge boson in high energy e+e- collisions in the Minimal Supersymmetric
Standard Model (MSSM). This associated production, which first arises at the
one loop level, offers the possibility of producing the charged Higgs boson at
the e+e- collider with mass more than half the center-of-mass energy, when the
charged Higgs pair production is kinematically forbidden. We present analytic
and numerical results for the cross section for e+e- --> W+ H- in the full
MSSM, taking into account the previously uncalculated contributions from
supersymmetric (SUSY) particles. We find that the contributions of the SUSY
particles enhance the cross section over most of SUSY parameter space,
especially when the SUSY particles are light, ~200 GeV. With favorable SUSY
parameters, at small tan beta, this process can yield more than ten
W^{\pm}H^{\mp} events for m_{H^{\pm}} <~ 350 GeV in 500 fb-1 at a 500 GeV e+e-
collider, or m_{H^{\pm}} <~ 600 GeV in 1000 fb-1 at a 1000 GeV collider. 80%
left-handed polarization of the e- beam improves these reaches to m_{H^{\pm}}
<~ 375 GeV and m_{H^{\pm}} <~ 670 GeV, respectively.Comment: v2: 21 pages, 9 figures, comments on Higgs search bounds and new
references added, and minor changes; v3: 23 pages, 11 figures, review of
literature moved from introduction to new Sec.5 and 2 plots added, references
added, typos corrected; v4: bug fixed in nu nubar H0 cross section (Fig.11),
version to appear in PR
- âŠ