Document Server@UHasselt
(3.246 recursos)
Repository of the University of Hasselt containing publications in the fields of statistics, computer science, information strategies and material from the Institute for behavioural sciences.
Mostrando recursos 1 - 20 de 47
1.
Application of the bibliometric distributions - Bookstein, A.
Two questions often asked of researchers in bibliometrics are : I) Do these distributions really exist ? and 2) How can they be applied ? We here suggest these two questions are related : that one way to defend the reality of these distributions is to demonstrate that one can make reasonable decisions in practical situations by using them. To indicate
how they can be applied, a microeconomic approach is taken to analyzing a specific, and in the library literature, often discussed, problem : how to allocate resources over various parts of a library book collection. A conceptualization of this problem...
2.
Mapping of Science : Critical elaboration and new approaches, a case study in agricultural biochemistry - Braam, R.R.; Moed, H.F.; Van Raan, A.F.J.
Mapping of science is studied in this project along several different lines. First, a critical elaboration of the classical method of co-citation duster analysis, developed by the Institute for Scientific Information
(ISI), is carried out. Secondly, a multi-database approach, focused on improvement of the interpretability of co-citation cluster structures, is
explored. Thirdly, recently developed data-analytical techniques, in particular quasi-correspondence analysis, are used to display citation relations on a journal Level. To explore our approach, data have been gathered from the research field of agriculture-related biochemistry. We here present preliminary results on co-citation cluster analysis, in
relation to field classification terms, and on journal-to-journal...
3.
Comments on the scope of bibliometrics - Brookes, B.C.
Bibliometrics emerged as a distinguishable study in 1969 at a time when, in the U.K. (as elsewhere too) university librarians were forced to abandon any 'Alexandrian' aims to be wholly selfsufficient. Close
interaction with the new British Library and its Lending Division called for techniques of selection and integration that had hitherto not been seriously needed. The concurrent applications to library work of
computers and developments in telecommunications helped to speed up these basic processes but also brought new problems and an abundance of data which invited exploration.
Recent developments in Statistics - notably the analysis and clarification of the 'long-tailed Zipfian' distributions...
4.
Predictive aspects of some biobliometric processes. - Burrell, Quentin L.
A statistical model for any bibliometric situation, whether i t be a frequency-of-citation distribution over a population of authors, a frequency-of-circulation distribution for a library collection or a Bradford type analysis of journal relevance in a field, is of most value when it can be used to guide future action. The model can be used as a predictive tool only if a time parameter features in the model explicitly, in which case we are obliged to consider not bibliometric distributions but bibliometric processes.
We consider various models for such processes and suggest ways in which they can be used for predictive...
5.
The Fussler sampling technique for populations with discrete or a continuous distribution of thickness - Egghe, Leo
In this paper we show that the Fussler sampling technique in book shelves is always better than systematic sampling by length. So far this result was only known to be true in the idealized situation of two
categories of books : "thin" and "thick" books (Bookstein, Rousseau).
In the present paper we allow any distribution of thicknesses of bookson the shelf and furthermore we show that the same result is true for systems with a continuous distributions of thicknesses, which has
applications in sampling by time.
6.
Theoretical and empirical studies of the tails of scientometric distributions - Glänzel, W.; Schubert, A.
The distributions of non-negative random variables occurring in scientometrics are said to have a proper tail if they asymptotically obey "Zipf's Law", i.e., if
lim (I-F(k)) k a = const
k- "
for some real a > 0 where F denotes the cumulative distribution. The tail of scientometric distributions has a particular significance because it generally contains the most "prominent" elements of the population
(e.g. highest cited papers or most productive authors). In addition, the tail parameter, a , is a sensitive indicator of several fundamental features of the whole distribution. It is shown that, among others, the tail parameter governs order and rank...
7.
Exact fits in bibliometrics : Some tools an results - Griffith, B.C.
The present paper takes an almost diametrically opposed approach to
that of recent work in bibliometrics, such as Sichel, which has been
concerned with increasing formalization. The reported series of
experiments start with versions of the simplest bibliometric models
utilizing few, and explicit parameters, and then, attempts to determine
how much structure in very large data sets can be readily and simply
explained. A system for the creation of empirical mathematical models
was developed, consisting of I) software for microcomputers and 2) a
basic discipline of analysis. Good fits to data were obtained and
replicated for large ranked distributions, for Lotka Law distributions,
and for literature growth and aging phenomena....
8.
On bibliometric modeling - Leimkuhler, F.F.
A common feature in bibliometric studies is the use of mathematical models to analyze fundamental problems arising from the operation of information systems. As bibliometrics develops, more explicit attention needs to be given to the modeling process as a unifying activity within the field, a vital link to other fields of study, and an avenue to future growth. In this paper the author draws on his experience with bibliometric modeling to demonstrate its practical and theoretical significance, and cites some recent computational developments that are revolutionizing modeling methodology.
9.
Co-words and citations relations between document sets and environments - Leydesdorff, L.; Zaal, R.
Co-word linkages among documents have been proposed as an
alternative to citations .(and co-citations) for the study of how
documents are related. In this study we examine co-word linkages
among a set of biochemistry documents which were subjected to a
citation analysis in another context. The co-word structure in the titles
of this document set is compared with that of the titles of the
documents which cited at least one of these documents, and with that
in all other documents of the Science Citation Index in the same
period. A similar analysis of the words used in the abstracts of these
documents has been made, to check whether one...
10.
Parameters for cluster analysis of library overlap - McGrath, W.E.
The relationship between two common approaches to library overlap is
discussed : I) the practice of tabulating frequencies of 0,1,2 ..., n
copies of titles in a network, and 2) reporting of the number of
co-occurring titles in a symmetric resemblance matrix. It is contended
that an understanding of the first approach is important in the
practice of the second approach-- e.g., in constructing a resemblance
coefficient between any two libraries and in establishing sample size
when the matrix is used as input for cluster analysis. The Poisson
and negative binomial distributions were tested for fit with several
samples of data. The negative binomial ditribution provides a much
better fit...
11.
The use of on-line databases for bibliometric analysis - Moed, H.J.
Databases containing bibliometric information on published scientific
literature play an impwtant role in the field of quantitative studies of
science and in the development and application of Science and
Technology indicators. For these purposes, perhaps the most important
and probably the most frequently used database is the Science Citation
Index, produced by the Institute for Scientific Information. SCISEARCH,
the on-line version of the Science Citation Index (SCI), is included in
several host computers. However, other databases are used as well,
such as Physics Abstracts or Chemical Abstracts.
In this contribution, potentialities and limitations of several online
databases as sources of bibliometric data in a number of host
computers will be discussed....
12.
The coverage of science in the thrid world : The "Philadelphia program" - Moravcsik, M.J.
A year-long study was conducted by a selected group of interested
people, culminating in a three-day workshop in Philadelphia in July
1985, exploring the extent to which the coverage of science in
bibliornetric data bases is adequate, and what measures could be taken
to eliminate the deficiencies in such coverage. The talk at the
conference will summarize the main conclusions and recommendations
of the final report of this effort. Since many of the recommendations
can be implemented in a decentralized way, the aim of the
presentation is to urge the individual members of the information
science community to participate in this implementation.
The recommendations are in five groups: I. Studies....
13.
Synchronous and diachronous citation distribution - Nakamoto, H.
Using the data of the Science Citation Index, it is confirmed that the decrease in citation by age is exponential and independent of the number of source publications. It is further shown that synchronous
and diachronous percentage distributions highly coincide. As such, data of synchronous distribution can replace data of diachronous distribution in literature studies.
14.
Bibliometric literature : A quantitative analysis - Peritz, B.C.
A preliminary analysis of the literature of bibliometrics for the period
1960-1985, based on several secondary sources, is presented. In spite of
the inherent limitations of such investigations a number of relevant
variables were extracted: I) the year of publication, which allows the
study of growth or other changes over time, 2) language, 3) the field
of the journal in which the paper was published, 4) the subject area
within bibliometrics with categories such as growth, scatter,
obsolescence, journal cores, bibliometric laws, citation analysis, etc.
Furthermore, a substantial number of papers in this body of data are
concerned with the bibliometric analysis of some specific discipline; the
distribution of these...
15.
Monitoring advances in chemical engineering - Peters, H.P.F.; Hartmann, D.; Van Raan, A.F.J.
This paper describes an approach to monitoring scientific progress in
chemical engineering in order to operationalize concepts such as
'research performance' which can be used in the retrospective
evaluation and the future anticipation of scientific research activities.
We focus on various quantitative methods. Bibliometric methods form
an important, but not the only, part of the work. The use of
bibliometric approaches and measures is plagued by many problems.
This is especially true for the more applied sciences, like chemical
engineering. Nevertheless, there is very few research on the problem of
the use of bibliometric indicators in applied sciences. The differences
between the many disciplines can be very large, and therefore...
16.
Réformulation des question dans l'interrogation des bases des donneés bibliographiques : Système Lexiquest - Pomian, J.
The purpose of the LEXIQUEST project is to introduce the use of artificial intelligence techniques in information retrieval. LEXIQUEST handles relations between indexing key-words. It helps the user to find out a meaningful formulation of his query, which is stated in free terms.
Most database interfaces provide the user with catalographic tools (lists of titles, authors, key words, and so on), but are unable to detect the user's preoccupation. Some systems, for example DIALECT or EXPRIM, use an interpretation of the user's request to reformulate his query. This is also the purpose of LEXIQUEST, but our system differs in that the...
17.
Exploiting the probability ranking principle to increase the effectiveness of conventional boolean retieval systems - Radecki, T.
This paper reports on research aimed at developing practical methods for improving the performance of conventional Boolean information
retrieval systems. More specifically, the objective of this research is to incorporate into these systems a mechanism for ranking the documents of a collection in descending order of their probabilities of usefulness
to the user. There are several reasons why a ranking mechanism of this type may be expected to provide retrieval results superior to those of traditional Boolean search techniques which normally do not furnish users with any indication of document relevance. In particular, the so-called output overload problem, which occurs when the...
18.
Deterministic strategies for query (re)formulation in information retrieval - Raghavan, V.V.
Relevance feedback is a process whereby a user examines the documents selected by a retrieval system and provides feedback to the system as to their relevance. Such a feedback can then be used to
formulate an optimal query with respect to the current information need of the user. This process of query (re)formulation can be based on probabilistic concepts, where Bayesian decision theory provides the framework for a decision rule, or ideas which instead employ deterministic strategies. The former class of techniques are limited by the fact that (strong) assumptions have to be made concerning the
nature of the conditional orobabilitv density...
19.
Probability distributions and inequality measures for analyses of circulation data - Ravichandra Rao, Inna Kedage
Bibliometric analysis of circulation data is a useful tool for effective
library management. For the purpose of such an analysis, the
theoretical basis is provided by the study of the distribution of
transactions. The negative binomial distribution is a good
approximation to describe the circulation distribution. Thus, the
phenomenon of the distribution of the transactions is a manifestation
of success-breeds- success phenomenon. However, for highly skewed,
long tailed, heterogeneous data, the negative binomial is unlikely to be
a good approximation. In such cases, one may derive a distribution
function by maximizing the entropy.
Further, various measures of inequality are found to be equally useful
in analyzing the data. Amongst these, Gini's...
20.
Citation distribution of pure mathematics journals - Rousseau, Ronald
Garfield defined the impact factor of a journal as the ratio of the
number of citations which this journal receives in the course of a
given year to the number of articles published by that journal within
the two preceding years.
We chose the field of pure mathematics for an experiment to see how
impact factors change when calculated in another way.
We first derive some mathematical formulae on raw data for impact
factors. Then we present our results on impact factors for pure
mathematics journals when calculated over several years and we study
the orderings resulting from these impact factors. We moreover study
the relation between mathematics journals and...
1.
