534 research outputs found
Coherent measures of the impact of co-authors in peer review journals and in proceedings publications
This paper focuses on the coauthor effect in different types of publications,
usually not equally respected in measuring research impact. {\it A priori}
unexpected relationships are found between the total coauthor core value,
, of a leading investigator (LI), and the related values for their
publications in either peer review journals () or in proceedings (). A
surprisingly linear relationship is found: . Furthermore, another relationship is found concerning the measure
of the total number of citations, , i.e. the surface of the citation
size-rank histogram up to . Another linear relationship exists :
. These empirical findings
coefficients (0.4 and 1.36) are supported by considerations based on an
empirical power law found between the number of joint publications of an author
and the rank of a coauthor. Moreover, a simple power law relationship is found
between and the number () of coauthors of a LI: ; the power law exponent depends on the type ( or ) of
publications. These simple relations, at this time limited to publications in
physics, imply that coauthors are a "more positive measure" of a principal
investigator role, in both types of scientific outputs, than the Hirsch index
could indicate. Therefore, to scorn upon co-authors in publications, in
particular in proceedings, is incorrect. On the contrary, the findings suggest
an immediate test of coherence of scientific authorship in scientific policy
processes.Comment: 22 pages; 2 Tables; 6 Figures; 38 references; prepared for Physica
Econophysics in Belgium. The first (?) 15 years
This reviews the econophysics activities in Belgium from my admittedly biased
point of view. Unknown historical notes or facts are presented for the first
time explaining the aims, whence evolution of the research papers and friendly
connections with colleagues. Comments on endeavors are also provided. The lack
of official, academic and private support is outlined.Comment: 6 pages, 79 refs.; written for "Econophysics", a special issue of
"Science and Culture" (Kolkata, India) to celebrate 15 years of Econophysic
A scientometrics law about co-authors and their ranking. The co-author core
Rather than "measuring" a scientist impact through the number of citations
which his/her published work can have generated, isn't it more appropriate to
consider his/her value through his/her scientific network performance
illustrated by his/her co-author role, thus focussing on his/her joint
publications, - and their impact through citations? Whence, on one hand, this
paper very briefly examines bibliometric laws, like the -index and
subsequent debate about co-authorship effects, but on the other hand, proposes
a measure of collaborative work through a new index. Based on data about the
publication output of a specific research group, a new bibliometric law is
found.
Let a co-author have written (joint) publications with one or several
colleagues. Rank all the co-authors of that individual according to their
number of joint publications, giving a rank to each co-author, starting
with for the most prolific.
It is empirically found that a very simple relationship holds between the
number of joint publications by coauthors and their rank of importance,
i.e. . Thereafter, in the same spirit as for the Hirsch core,
one can define a "co-author core", and introduce indices operating on an
author. It is emphasized that the new index has a quite different
(philosophical) perspective that the -index. In the present case, one
focusses on "relevant" persons rather than on "relevant" publications.
Although the numerical discussion is based on one case, there is little doubt
that the law can be verified in many other situations. Therefore, variants and
generalizations could be later produced in order to quantify co-author roles,
in a temporary or long lasting stable team(s), and lead to criteria about
funding, career measurements or even induce career strategies.Comment: REVISED VERSION : 3 figures, 13 pages, 82 references, 3 tables;
post-conference paper for COST Action MP-0801, 'Physics of Competition and
Conflict': In particular "Evaluating Science: Modern Scientometric Methods",
in Sofia,May 201
Econophysics of Stock and Foreign Currency Exchange Markets
Econophysics is a science in its infancy, born about ten years ago at this
time of writing, at the crossing roads of physics, mathematics, computing and
of course economics and finance. It also covers human sciences, because all
economics is ultimately driven by human decision. From this human factor,
econophysics has no hope to achieve the status of an exact science, but it is
interesting to discover what can be achieved, discovering potential limits and
trying try to push further away these limits. A few data analysis techniques
are described with emphasis on the Detrended Fluctuation Analysis () and
the Zipf Analysis Technique (). Information about the original data
aresketchy, but the data concerns mainly the foreign currency exchange market.
The robustness of the technique is underlined. Additional remarks are
given for suggesting further work. Models about financial value evolutions are
recalled, again without going into elaborate work discussing typical agent
behaviors, but rather with hopefully sufficient information such that the basic
ingredients can be memorized before reading some of the vast literature on
price formation. Crashes being spectacular phenomena retain our attention and
do so through data analysis and basic intuitive models. A few statistical and
microscopic models are outlined.Comment: intended as a review to be published in a book edited by B.K.
Chakrabarti, A. Chakraborti and A. Chatterjee, Wiley-VCH, Berlin : 25 pages,
3 figures, 2 tables, 94 reference
Toward fits to scaling-like data, but with inflection points & generalized Lavalette function
Experimental and empirical data are often analyzed on log-log plots in order
to find some scaling argument for the observed/examined phenomenon at hands, in
particular for rank-size rule research, but also in critical phenomena in
thermodynamics, and in fractal geometry. The fit to a straight line on such
plots is not always satisfactory. Deviations occur at low, intermediate and
high regimes along the log()-axis. Several improvements of the mere power
law fit are discussed, in particular through a Mandelbrot trick at low rank and
a Lavalette power law cut-off at high rank. In so doing, the number of free
parameters increases. Their meaning is discussed, up to the 5 parameter free
super-generalized Lavalette law and the 7-parameter free hyper-generalized
Lavalette law. It is emphasized that the interest of the basic 2-parameter free
Lavalette law and the subsequent generalizations resides in its "noid" (or
sigmoid, depending on the sign of the exponents) form on a semi-log plot;
something incapable to be found in other empirical law, like the
Zipf-Pareto-Mandelbrot law. It remained for completeness to invent a simple law
showing an inflection point on a \underline{log-log plot}. Such a law can
result from a transformation of the Lavalette law through
log(), but this meaning is theoretically unclear. However, a simple linear
combination of two basic Lavalette law is shown to provide the requested
feature. Generalizations taking into account two super-generalized or
hyper-generalized Lavalette laws are suggested, but need to be fully considered
at fit time on appropriate data.Comment: 31 pages, 38 references, 22 figures, prepared for Journal of Applied
Quantitative Method
A biased view of a few possible components when reflecting on the present decade financial and economic crisis
Is the present economic and financial crisis similar to some previous one? It
would be so nice to prove that universality laws exist for predicting such rare
events under a minimum set of realistic hypotheses. First, I briefly recall
whether patterns, like business cycles, are indeed found, and can be modeled
within a statistical physics, or econophysics, framework. I point to a
simulation model for describing such so called business cycles, under exo- and
endo-genous conditions I discuss self-organized and provoked crashes and their
predictions. I emphasize the role of an of- ten forgotten ingredient: the time
delay in the information flow. I wonder about the information content of
financial data, its mis-interpretation and market manipulation.Comment: 13 pages; 70 refs.; a chapter prepared for "Polymorphic Crisis
Readings on the Great Recession of the 21st century" edited by Roy Cerquet
Logistic Modeling of a Religious Sect Features
The financial characteristics of sects are challenging topics. The present
paper concerns the Antoinist Cult community (ACC), which has appeared at the
end of the 19-th century in Belgium, have had quite an expansion, and is now
decaying. The historical perspective is described in an Appendix. Although
surely of marginal importance in religious history, the numerical and analytic
description of the ACC growth AND decay evolution per se should hopefully
permit generalizations toward behaviors of other sects, with either longer life
time, i.e. so called religions or churches, or to others with shorter life
time. Due to the specific aims and rules of the community, in particular the
lack of proselytism, and strict acceptance of only anonymous financial gifts,
an indirect measure of their member number evolution can only be studied. This
is done here first through the time dependence of new temple inaugurations,
between 1910 and 1940. Besides, the community yearly financial reports can be
analyzed. They are legally known between 1920 and 2000. Interestingly, several
regimes are seen, with different time spans. The agent based model chosen to
describe both temple number and finance evolutions is the Verhulst logistic
function taking into account the limited resources of the population. Such a
function remarkably fits the number of temple evolution, taking into account a
no construction time gap, historically explained. The empirical Gompertz law
can also be used for fitting this number of temple evolution data, as shown in
an Appendix. It is thereby concluded that strong social forces have been acting
both in the growth and decay phases.Comment: 21 pages, 8 figures, 57 references; an updated version will be
published in 'Econophysics of Agent-Based Models: Proc. Econophys-Kolkata
VII', Eds. F. Abergel et al, Springer (2014
Two-exponent Lavalette function. A generalization for the case of adherents to a religious movement
The Lavalette function is generalized to a 2-exponent function in order to
represent data looking like a sigmoid on semi-log plots. A Mandelbrot trick is
suggested for further investigations, if more fit parameters are needed. The
analyzed data is that of the number of adherents to the main religions in the
XXth century.Comment: 4 pages, 2 columns, 4 figures, 20 reference
For A Lecture on Scientific Meteorology within Statistical ("Pure") Physics Concepts
Various aspects of modern statistical physics and meteorology can be tied
together. Critical comments have to be made. However, the historical importance
of the University of Wroclaw in the field of meteorology should be first
pointed out. Next, some basic difference about time and space scales between
meteorology and climatology can be outlined. The nature and role of clouds both
from a geometric and thermal point of view are recalled. Recent studies of
scaling laws for atmospheric variables are mentioned, like studies on cirrus
ice content, brightness temperature, liquid water path fluctuations, cloud base
height fluctuations, .... Technical time series analysis approaches based on
modern statistical physics considerations are outlined.Comment: the originally extended version of
http://arXiv.org/abs/physics/0401066 as presented at the 18-th Max Born
Symposium entitled "*Physics: Statistical Physics outside Physics", Ladek
Zdroj, Poland, September 22-25, 200
Assessing the true role of coauthors in the h-index measure of an author scientific impact
A method based on the classical principal component analysis leads to
demonstrate that the role of co-authors should give a h-index measure to a
group leader higher than usually accepted. The method rather easily gives what
is usually searched for, i.e. an estimate of the role (or "weight") of
co-authors, as the additional value to an author papers' popularity. The
construction of the co-authorship popularity H-matrix is exemplified and the
role of eigenvalues and the main eigenvector component are discussed. An
example illustrates the points and serves as the basis for suggesting a
generally practical application of the concept.Comment: 13 pages ; 40 ref
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