567 research outputs found
Transition to hexagonal pattern under the variation of intrinsic length scales of a reaction diffusion system
The intrinsic length scales of a reaction diffusion system (Gierer-Meinhardt
model)is varied by quasi-statically changing the diffusion constant of the
activator and a transition from rolls to hexagon is detected. The transition is
hysteretic or first order like. From stability analysis, we also analytically
show the possibility of such transitions.Comment: One .tex file and four .ps file
Scaling of internode distances in weighted complex networks
We extend the previously observed scaling equation connecting the internode
distances and nodes' degrees onto the case of weighted networks. We show that
the scaling takes a similar form in the empirical data obtained from networks
characterized by different relations between node's strength and its degree. In
the case of explicit equation for s(k) (e.g. linear or scale-free), the new
coefficients of scaling equation can be easily obtained. We support our
analysis with numerical simulations for Erdos-Renyi random graphs with
different weight distributions.Comment: 9 pages, 4 figures, submitted to International Journal of Modern
Physics
Statistical analysis of 22 public transport networks in Poland
Public transport systems in 22 Polish cities have been analyzed. Sizes of
these networks range from N=152 to N=2881. Depending on the assumed definition
of network topology the degree distribution can follow a power law or can be
described by an exponential function. Distributions of paths in all considered
networks are given by asymmetric, unimodal functions. Clustering, assortativity
and betweenness are studied. All considered networks exhibit small world
behavior and are hierarchically organized. A transition between dissortative
small networks N=500 is observed.Comment: 11 pages, 17 figures, 2 tables, REVTEX4 forma
Social Aspects of New Technologies - the CCTV and Biometric (Framing Privacy and Data Protection) in the Case of Poland
The purpose of this paper is to review the institution responsible for the protection of personal data within the European Union and national example - Polish as a country representing the new Member States. The analysis of institutional system - providing legal security of communication and information institutions, companies and citizens against the dangers arising from the ongoing development of innovative new technologies in the European Union and Poland. This article is an attempt to analyze the possibility of using security systems and Biometry CTTV in Poland in terms of legislation. The results of the analysis indicate that, in terms of institutions Poland did not do badly in relation to the risks arising from the implementation of technology. The situation is not as good when it comes to the awareness of citizens and small businesses. This requires that facilitate greater access to free security software companies from data leakage or uncontrolled cyber-terrorist attacks. With regard to the use of security systems, CCTV and biometrics, Poland in legal terms is still early in the process of adapting to EU Directive. The continuous development of technology should force the legislature to establish clear standards and regulations for the application of CCTV technology and biometrics, as it is of great importance in ensuring the fundamental rights and freedoms of every citizen of the Polish Republic.Wyniki analizy wskazują, że pod względem instytucji Polska nie wypada źle w odniesieniu do zagrożeń wynikających z wdrożenia technologii. Sytuacja nie jest tak dobra, jeśli chodzi o świadomość obywateli i mniejszych firm. Wymaga to ułatwiania szerszego dostępu do darmowych programów zabezpieczających firmy przed wyciekiem danych lub niekontrolowanych cyber-ataków terrorystycznych. W odniesieniu do stosowania systemów zabezpieczeń CCTV oraz biometrii, Polska pod względem prawnym jest wciąż na początku procesu dostosowania do dyrektywy UE. Ciągły rozwój technologii powinien zmusić ustawodawcę do stworzenia jednoznacznych standardów i przepisów obowiązujących w zakresie stosowania technologii CCTV oraz biometrii, gdyż ma to ogromne znaczenie w zapewnieniu podstawowych praw i wolności każdego obywatela Rzeczypospolitej Polskiej
Dynamic structural and topological phase transitions on the Warsaw Stock Exchange: A phenomenological approach
We study the crash dynamics of the Warsaw Stock Exchange (WSE) by using the
Minimal Spanning Tree (MST) networks. We find the transition of the complex
network during its evolution from a (hierarchical) power law MST network,
representing the stable state of WSE before the recent worldwide financial
crash, to a superstar-like (or superhub) MST network of the market decorated by
a hierarchy of trees (being, perhaps, an unstable, intermediate market state).
Subsequently, we observed a transition from this complex tree to the topology
of the (hierarchical) power law MST network decorated by several star-like
trees or hubs. This structure and topology represent, perhaps, the WSE after
the worldwide financial crash, and could be considered to be an aftershock. Our
results can serve as an empirical foundation for a future theory of dynamic
structural and topological phase transitions on financial markets
The role of emotional variables in the classification and prediction of collective social dynamics
We demonstrate the power of data mining techniques for the analysis of
collective social dynamics within British Tweets during the Olympic Games 2012.
The classification accuracy of online activities related to the successes of
British athletes significantly improved when emotional components of tweets
were taken into account, but employing emotional variables for activity
prediction decreased the classifiers' quality. The approach could be easily
adopted for any prediction or classification study with a set of
problem-specific variables.Comment: 16 pages, 9 figures, 2 tables and 1 appendi
Helioseismology and the solar age
The problem of measuring the solar age by means of helioseismology hasbeen
recently revisited by Guenther & Demarque (1997) and by Weiss & Schlattl
(1998). Different best values for and different assessment of
the uncertainty resulted from these two works. We show that depending on the
way seismic data are used, one may obtain the value
Gy, close to the age of the oldest meteorites, Gy, like in
the first paper, or above 5 Gy like in the second paper. The discrepancy in the
seismic estimates of the solar age may be eliminated by assuming higher than
the standard metal abundance and/or an upward revision of the opacities in the
solar radiative interior.We argue that the most accurate and robust seismic
measure of the solar age are the small frequency separations,
, for spherical harmonic degrees
and radial orders .The seismic age inferred by
minimization of the sum of squared differences between the model and the solar
small separations is , a number consistent with
meteoritic data.Our analysis supports earlier suggestions of using small
frequency separations as stellar age indicators.Comment: 8 pages + 4 ps figures included, LaTeX file with l-aa.sty, submitted
to Astronomy and Astrophysic
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