1,511 research outputs found
Metodologia badań politologicznych na przykładzie eurazjatyzmu
The text answers the following question: what is the point of conducting political science research? The research can make a lot of sense when you are strongly motivated and, motivation is just as important as your knowledge how to do it. In the latter case, you must proceed in the correct order. Firstly, the boundaries of the research field should be set, and secondly, original and unconventional research problems and hypotheses should be defined. Thirdly, the proper selection of primary and secondary sources is necessary. Fourthly, you choose appropriate research methods and techniques, and then construct a research tool or tools. After the determining of the level of accuracy and relevance of data collected, it is possible to proceed to the verification of hypotheses. The more thorough the process and the more inquisitive researcher, the more interesting research results are obtained.Tekst odpowiada na pytanie: jaki jest sens prowadzenia badań politologicznych? Wtedy, gdy ma się odpowiednią motywację i (co równie ważne) wie się, jak to można zrobić. W tym drugim przypadku musi się postępować w odpowiedniej kolejności. Po pierwsze, należy wyznaczyć granice pola badawczego, a po drugie, określić oryginalne, niebanalne problemy i hipotezy badawcze. Po trzecie, konieczny jest odpowiedni dobór i sposób selekcji źródeł pierwotnych i ewentualnie wtórnych. Czwartym etapem jest dobranie adekwatnych metod i technik badawczych, a następnie skonstruowanie narzędzia lub narzędzi badawczych. Po określeniu poziomu prawdziwości i stosowalności zebranych informacji możliwe jest dopiero przystąpienie do weryfikacji hipotez. Im bardziej ten ostatni proces będzie rzetelny, a badacz dociekliwy, tym ciekawsze uzyska się rezultaty badawcze
Optimal neuronal tuning for finite stimulus spaces
The efficiency of neuronal encoding in sensory and motor systems has been proposed as a first principle governing response properties within the central nervous system. We present a continuation of a theoretical study presented by Zhang and Sejnowski, where the influence of neuronal tuning properties on encoding accuracy is analyzed using information theory. When a finite stimulus space is considered, we show that the encoding accuracy improves with narrow tuning for one- and two-dimensional stimuli. For three dimensions and higher, there is an optimal tuning width
Resonance-assisted tunneling in deformed optical microdisks with a mixed phase space
The lifetimes of optical modes in whispering-gallery cavities depend crucially on the underlying classical ray dynamics, and they may be spoiled by the presence of classical nonlinear resonances due to resonance-assisted tunneling. Here we present an intuitive semiclassical picture that allows for an accurate prediction of decay rates of optical modes in systems with a mixed phase space. We also extend the perturbative description from near-integrable systems to systems with a mixed phase space, and we find equally good agreement. Both approaches are based on the approximation of the actual ray dynamics by an integrable Hamiltonian, which enables us to perform a semiclassical quantization of the system and to introduce a ray-based description of the decay of optical modes. The coupling between them is determined either perturbatively or semiclassically in terms of complex paths
Homoclinic points of 2-D and 4-D maps via the Parametrization Method
An interesting problem in solid state physics is to compute discrete breather
solutions in coupled 1--dimensional Hamiltonian particle chains
and investigate the richness of their interactions. One way to do this is to
compute the homoclinic intersections of invariant manifolds of a saddle point
located at the origin of a class of --dimensional invertible
maps. In this paper we apply the parametrization method to express these
manifolds analytically as series expansions and compute their intersections
numerically to high precision. We first carry out this procedure for a
2--dimensional (2--D) family of generalized Henon maps (=1), prove
the existence of a hyperbolic set in the non-dissipative case and show that it
is directly connected to the existence of a homoclinic orbit at the origin.
Introducing dissipation we demonstrate that a homoclinic tangency occurs beyond
which the homoclinic intersection disappears. Proceeding to , we
use the same approach to determine the homoclinic intersections of the
invariant manifolds of a saddle point at the origin of a 4--D map consisting of
two coupled 2--D cubic H\'enon maps. In dependence of the coupling the
homoclinic intersection is determined, which ceases to exist once a certain
amount of dissipation is present. We discuss an application of our results to
the study of discrete breathers in two linearly coupled 1--dimensional particle
chains with nearest--neighbor interactions and a Klein--Gordon on site
potential.Comment: 24 pages, 10 figures, videos can be found at
https://comp-phys.tu-dresden.de/supp
Coupling of bouncing-ball modes to the chaotic sea and their counting function
We study the coupling of bouncing-ball modes to chaotic modes in
two-dimensional billiards with two parallel boundary segments. Analytically, we
predict the corresponding decay rates using the fictitious integrable system
approach. Agreement with numerically determined rates is found for the stadium
and the cosine billiard. We use this result to predict the asymptotic behavior
of the counting function N_bb(E) ~ E^\delta. For the stadium billiard we find
agreement with the previous result \delta = 3/4. For the cosine billiard we
derive \delta = 5/8, which is confirmed numerically and is well below the
previously predicted upper bound \delta=9/10.Comment: 10 pages, 6 figure
Temporal flooding of regular islands by chaotic wave packets
We investigate the time evolution of wave packets in systems with a mixed
phase space where regular islands and chaotic motion coexist. For wave packets
started in the chaotic sea on average the weight on a quantized torus of the
regular island increases due to dynamical tunneling. This flooding weight
initially increases linearly and saturates to a value which varies from torus
to torus. We demonstrate for the asymptotic flooding weight universal scaling
with an effective tunneling coupling for quantum maps and the mushroom
billiard. This universality is reproduced by a suitable random matrix model
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