Field-Weighted XML Retrieval Based on BM25.

This is the first year for the Centre for Interactive Systems Research participation of INEX. Based on a newly developed XML indexing and retrieval system on Okapi, we extend Robertson’s field-weighted BM25F for document retrieval to element level retrieval function BM25E. In this paper, we introduce this new function and our experimental method in detail, and then show how we tuned weights for our selected fields by using INEX 2004 topics and assessments. Based on the tuned models we submitted our runs for CO.Thorough, CO.FetchBrowse, the methods we propose show real promise. Existing problems and future work are also discussed

A grid-based infrastructure for distributed retrieval

In large-scale distributed retrieval, challenges of latency, heterogeneity, and dynamicity emphasise the importance of infrastructural support in reducing the development costs of state-of-the-art solutions. We present a service-based infrastructure for distributed retrieval which blends middleware facilities and a design framework to ‘lift’ the resource sharing approach and the computational services of a European Grid platform into the domain of e-Science applications. In this paper, we give an overview of the DILIGENT Search Framework and illustrate its exploitation in the field of Earth Science

Representing aggregate works in the digital library

This paper studies the challenge of representing aggregate works such as encyclopedias, collected poems and journals in heterogenous digital library collections. Reflecting on the materials used by humanities academics, we demonstrate the varied range of aggregate types and the problems of faithfully representing this in the DL interface. Aggregates are complex and pervasive, challenge common assumptions and confuse boundaries within organisational structures. Existing DL systems can only provide imperfect representation of aggregates, and alterations to document encoding are insufficient to create a faithful reproduction of the physical library. The challenge is amplified through concrete examples, and solutions are demonstrated in a well-known DL system and related to standard DL architecture

Webometric analysis of departments of librarianship and information science: a follow-up study

This paper reports an analysis of the websites of UK departments of library and information science. Inlink counts of these websites revealed no statistically significant correlation with the quality of the research carried out by these departments, as quantified using departmental grades in the 2001 Research Assessment Exercise and citations in Google Scholar to publications submitted for that Exercise. Reasons for this lack of correlation include: difficulties in disambiguating departmental websites from larger institutional structures; the relatively small amount of research-related material in departmental websites; and limitations in the ways that current Web search engines process linkages to URLs. It is concluded that departmental-level webometric analyses do not at present provide an appropriate technique for evaluating academic research quality, and, more generally, that standards are needed for the formatting of URLs if inlinks are to become firmly established as a tool for website analysis

Nonextensivity and Galaxy Clustering in the Universe

We investigate two important questions about the use of the nonextensive thermostatistics (NETS) formalism in the context of nonlinear galaxy clustering in the Universe. Firstly, we define a quantitative criterion for justifying nonextensivity at different physical scales. Then, we discuss the physics behind the ansatz of the entropic parameter $q(r)$. Our results suggest the approximate range where nonextensivity can be justified and, hence, give some support to the applicability of NETS to the study of large scale structures.Comment: 8 pages, written version of a talk presented in the International Workshop on Trends and Perspectives on Extensive and Non-Extensive Statistical Mechanics. Accepted for publication in Physica

A tachyonic scalar field with mutually interacting components

We investigate the tachyonic cosmological potential $V(\phi)$ in two different cases of the quasi-exponential expansion of universe and discuss various forms of interaction between the two components---matter and the cosmological constant--- of the tachyonic scalar field, which leads to the viable solutions of their respective energy densities. The distinction among the interaction forms is shown to appear in the $O_{m}(x)$ diagnostic. Further, the role of the high- and low-redshift observations of the Hubble parameter is discussed to determine the proportionality constants and hence the correct form of matter--cosmological constant interaction.Comment: 14 page

The Similarity Hypothesis in General Relativity

Self-similar models are important in general relativity and other fundamental theories. In this paper we shall discuss the ``similarity hypothesis'', which asserts that under a variety of physical circumstances solutions of these theories will naturally evolve to a self-similar form. We will find there is good evidence for this in the context of both spatially homogenous and inhomogeneous cosmological models, although in some cases the self-similar model is only an intermediate attractor. There are also a wide variety of situations, including critical pheneomena, in which spherically symmetric models tend towards self-similarity. However, this does not happen in all cases and it is it is important to understand the prerequisites for the conjecture.Comment: to be submitted to Gen. Rel. Gra