Temat: 89.75.-k - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Crowd Behavior as an Example of the Evolution of a Complex System - Evacuation Models Proposal Based on the Symmetry Analysis Approach
Autorzy:: Sikora, W.
Malinowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1399031.pdf
Data publikacji:: 2013-12
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.75.-k
Opis:: The evacuation of football stadium scenarios as examples of evolution of complex system are discussed. The models are presented as movements of individuals according to fields of displacements, calculated correspondingly to the given scenario. The assumption has been made that the most efficient evacuation is left based on the accordance of symmetry of allowed space, and this symmetry is taken into account while calculating the displacements field. The displacements related to every point of this space are calculated by the symmetry analysis method and fulfill the symmetry conditions of allowed space. The speed of each individual at every point in the presented model has the same quantity. Consequently, the times of evacuation and average presses acting on individuals during the evacuation are given. Both parameters are compared with and without symmetry considerations. They are calculated in the simulation procedure. For the realization of the simulation tasks the new program (using modified Helbing model) has been elaborated.
Źródło:: Acta Physica Polonica A; 2013, 124, 6; 1005-1012
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Monte Carlo Studies of the p-Spin Models οn Scale-Free Hypernetworks
Autorzy:: Krawiecki, A.
Powiązania:: https://bibliotekanauki.pl/articles/1400177.pdf
Data publikacji:: 2013-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.75.-k
89.75.Hc
05.70.Fh
Opis:: Results of Monte Carlo simulations of p-spin models on scale-free hypernetworks are presented. The hypernetworks are obtained using the preferential attachment algorithm, the spins are located in the nodes and the hyperedges connecting p nodes correspond to non-zero ferromagnetic interactions involving p spins. Such models show high degeneracy of the ground state: apart from the ferromagnetic state, depending on the parameters of the preferential attachment algorithm leading to different topologies of the obtained hypernetworks, there are several or even infinitely many disordered (glassy) states with the same energy. For various network topologies quantities such as the specific heat or magnetic susceptibility show maxima as functions of the temperature, which suggests the occurrence of the glassy or ferromagnetic phase transition. The models under study may serve as a starting point for modelling various forms of cooperation in social and economic sciences involving many-body rather than two-body interactions.
Źródło:: Acta Physica Polonica A; 2013, 123, 3; 564-566
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Structural Transformation of Minimal Spanning Trees in World Commodity Market
Autorzy:: Lee, J.
Nobi, A.
Powiązania:: https://bibliotekanauki.pl/articles/1029531.pdf
Data publikacji:: 2018-06
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.20.-a
89.65.Gh
89.75.-k
Opis:: We consider structural change of a world trade-flow network for different commodities from 1995 to 2013. A minimum spanning tree is generated from the trade flow data, and we investigate the hierarchical organization of the tree by changing the hub node. Only a few countries are the hub nodes for many of the commodities. We observed the structural transitions, from a chain-like tree (many countries are hub nodes) to a bi-starlike tree (only two countries are hub nodes). In the bi-starlike tree, China and Germany are the only two hub nodes.
Źródło:: Acta Physica Polonica A; 2018, 133, 6; 1414-1416
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Spanning Trees of the World Trade Web: Real-World Data and the Gravity Model of Trade
Autorzy:: Skowron, P.
Karpiarz, M.
Fronczak, A.
Fronczak, P.
Powiązania:: https://bibliotekanauki.pl/articles/1388204.pdf
Data publikacji:: 2015-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.75.-k
89.65.Gh
89.65.-s
Opis:: In this paper, we investigate the statistical features of the weighted international-trade network. By finding the maximum weight spanning trees for this network we make the extraction of the truly relevant connections forming the network's backbone. We discuss the role of large-sized countries (strongest economies) in the tree. Finally, we compare the topological properties of this backbone to the maximum weight spanning trees obtained from the gravity model of trade. We show that the model correctly reproduces the backbone of the real-world economy.
Źródło:: Acta Physica Polonica A; 2015, 127, 3A; A-123-A-128
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Cross-Correlations in Warsaw Stock Exchange
Autorzy:: Rak, R.
Kwapień, J.
Oświęcimka, P.
Drożdż, S.
Powiązania:: https://bibliotekanauki.pl/articles/1812226.pdf
Data publikacji:: 2008-09
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.20.-a
89.65.Gh
89.75.-k
Opis:: We study the inter-stock correlations for the largest companies listed on Warsaw Stock Exchange and included in the WIG20 index. Our results from the correlation matrix analysis indicate that the Polish stock market can be well described by a one-factor model. We also show that the stock- stock correlations tend to increase with the timescale of returns and they approach a saturation level for the timescales of at least 200 min, i.e. an order of magnitude longer than in the case of some developed markets. We also show that the strength of correlations among the stocks crucially depends on their capitalization. These results combined with our earlier findings together suggest that now the Polish stock market situates itself somewhere between an emerging market phase and a mature market phase.
Źródło:: Acta Physica Polonica A; 2008, 114, 3; 561-568
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Google Matrix of the World Trade Network
Autorzy:: Ermann, L.
Shepelyansky, D.
Powiązania:: https://bibliotekanauki.pl/articles/1492497.pdf
Data publikacji:: 2011-12
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.65.Gh
89.75.Hc
89.75.-k
89.20.Hh
Opis:: Using the United Nations Commodity Trade Statistics Database we construct the Google matrix of the world trade network and analyze its properties for various trade commodities for all countries and all available years from 1962 to 2009. The trade flows on this network are classified with the help of PageRank and CheiRank algorithms developed for the World Wide Web and other large scale directed networks. For the world trade this ranking treats all countries on equal democratic grounds independent of country richness. Still this method puts at the top a group of industrially developed countries for trade in all commodities. Our study establishes the existence of two solid state like domains of rich and poor countries which remain stable in time, while the majority of countries are shown to be in a gas like phase with strong rank fluctuations. A simple random matrix model provides a good description of statistical distribution of countries in two-dimensional rank plane. The comparison with usual ranking by export and import highlights new features and possibilities of our approach.
Źródło:: Acta Physica Polonica A; 2011, 120, 6A; A-158-A-171
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Partial Mutual Information Analysis of Financial Networks
Autorzy:: Fiedor, P.
Powiązania:: https://bibliotekanauki.pl/articles/1402928.pdf
Data publikacji:: 2015-03
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.65.Gh
89.75.-k
05.45.-a
Opis:: The econophysics approach to socio-economic systems is based on the assumption of their complexity. Such assumption inevitably leads to another assumption, namely that underlying interconnections within socio-economic systems, particularly financial markets, are nonlinear, which is shown to be true even in mainstream economic literature. Thus it is surprising to see that network analysis of financial markets is based on linear correlation and its derivatives. An analysis based on partial correlation is of particular interest as it leads to the vicinity of causality detection in time series analysis. In this paper we generalise the planar maximally filtered graphs and partial correlation planar graphs to incorporate nonlinearity using partial mutual information.
Źródło:: Acta Physica Polonica A; 2015, 127, 3; 863-867
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The SIRS Model of Epidemic Spreading in Virtual Society
Autorzy:: Grabowski, A.
Kosiński, R.
Powiązania:: https://bibliotekanauki.pl/articles/1812230.pdf
Data publikacji:: 2008-09
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.75.-k
89.65.-s
87.10.-e
Opis:: The phenomenon of epidemic spreading in a real social network is described and investigated numerically. On the basis of data concerning amount of time devoted daily to social interactions, the influence of human activity on spreading process is investigated in the frame of SIRS model. It was found that the activity of an individual is positively correlated with its connectivity and the relation has power law form. The influence of control measures on the spreading process is investigated as a function of initial conditions. The cost-effectiveness of mass immunizations campaigns and target vaccinations is compared. It was found that the form of activity distribution has significant influence on the spreading phenomena in the network.
Źródło:: Acta Physica Polonica A; 2008, 114, 3; 589-596
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Methods of non-extensive statistical physics in analysis of price returns on Polish stock market
Autorzy:: Bil, Ł.
Grech, D.
Podhajska, E.
Powiązania:: https://bibliotekanauki.pl/articles/1075477.pdf
Data publikacji:: 2016-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 05.45.Tp
89.75.Da
89.65.Gh
89.75.-k
Opis:: We use methods of non-extensive statistical physics to describe quantitatively the memory effect involved in returns of companies from WIG 30 index on the Warsaw Stock Exchange. The entropic approach based on the generalization of the Boltzmann-Gibbs entropy to non-additive Tsallis q-entropy is applied to fit fat tailed distribution of returns to q-normal (Tsallis) distribution. The existence of long term memory effects in price returns generated by two-point autocorrelations are checked via calculation of the Hurst exponent within detrended fluctuation analysis approach. The results are collected for diversified frequency of data sampling. We confirm the perfect inverse cubic power law for low time-lags (≈1 min) of returns for the main WIG 30 index as well as for the most of separate stocks, however this relationship does not hold for longer time-lags. The particular emphasis is given to a study of an independent fit of probability distribution of positive and negative returns to q-normal distribution. We discuss in this context the asymmetry between tails in terms of the Tsallis parameters q^{±}. A qualitative and quantitative relationship between the frequency of data sampling, the parameters q and q^{±}, and the corresponding main Hurst exponent H is provided to analyze the effect of memory in data caused by linear and nonlinear autocorrelations. A new quantifier based on asymmetry of the Tsallis index instead of skewness of distribution is proposed which we believe is able to describe the stage of market development and its robustness to speculation.
Źródło:: Acta Physica Polonica A; 2016, 129, 5; 986-992
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Quantitative Characteristics of Correlations of Meteorological Data
Autorzy:: Rak, R.
Bwanakare, S.
Powiązania:: https://bibliotekanauki.pl/articles/1398837.pdf
Data publikacji:: 2016-05
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:: 89.75.-k
89.75.Da
89.65.Gh
02.70.Rr
Opis:: This paper presents the quantitative characteristics of correlations (and cross-correlations) of plant main eco-factors i.e. the ground and over-ground temperature, the wind speed, and the humidity. The study is based upon hourly data statistical observations collected in the region of Lublin, in Poland for the period 2001.05.07-2009.04.10. This paper indicates that plant growth conditions constitute an emergent response to the above direct eco-factors. Then, the dynamics properties of each eco-factor is first analyzed alone for its multifractal structure. We apply the multifractal detrended correlation analysis and multifractal detrended cross-correlation analysis. We show that the widest multifractal spectrum is for over-ground temperature and the strongest power-law cross-correlations exist between ground and over-ground temperature. Next, an impulse response analysis is carried out to measure dynamical inter causalities within all the considered variables. As far as cross-impact between different eco-variables is concerned, one observes that the wind speed, the ground temperature and the air humidity dynamics are the most influenced, in terms of memory length time, by external temperature.
Źródło:: Acta Physica Polonica A; 2016, 129, 5; 922-926
0587-4246
1898-794X
Pojawia się w:: Acta Physica Polonica A
Dostawca treści:: Biblioteka Nauki

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