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1
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Real Estate Market under Catastrophic Change

100%
Bełej M., Kulesza S.
Acta Physica Polonica A
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2013
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vol. 123
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issue 3
497-501
EN
Within the last decade, real estate prices in Poland have changed significantly. We believe that these prices inevitably reflect the dynamics of the real estate market, and therefore they can be used to track its evolution path. To study whether and how the prices (regarded as a state variable) change over time depending on such control variables as gross domestic product and central bank interest rates, the theory of discontinuous change (also known as the catastrophe theory) was used. Catastrophic model assumes that small price fluctuations are associated with stable, long-term development of the market, whereas rapid changes are always due to short-term instabilities. In such a picture, the system evolution path draws a smooth curve within the stability area passing continuously between neighboring equilibrium states, and it rarely enters into the instability area to jump over the potential barrier to another equilibrium state.
2
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The Mechanism of Transformation of Global Business Cycles into Dynamics of Regional Real Estate Markets

100%
Jakimowicz A., Kulesza S.
Acta Physica Polonica A
|
2018
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vol. 133
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issue 6
1351-1361
EN
The aim of this article is the identification of the occurrence mechanism of sudden quantitative changes in real-estate market prices, which were observed during the global financial crisis. Since such phenomena did not occur to such an intensity during previous crises, it can be assumed that a new economic dynamic type has emerged in real-estate markets. The most promising of the methods of studying such phenomena seems to be the bifurcation method and particularly the catastrophe theory. This study analyzes changes in the prices of residential property based on cusp catastrophes. Empirical data were fit to a stochastic cusp model to visualize the evolutionary path of real estate market. Two other popular models (linear and logistic) were also estimated to compare results. A comparative analysis proved that the cusp model can best explain structural price instabilities in real-estate markets. The results confirmed that the evolution of the real estate market combines two processes: long-term evolution in the area of non-degenerate stability and discontinuous changes in the area of degenerate stability. Structural changes take place in the system only in the area of degenerate stability. The theoretical and practical results show that the catastrophe theory may have predictive potential, which could support traditional methods of predicting changes on real estate markets.
3
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Local Real Estate Markets in Poland as a Network of Damped Harmonic Oscillators

100%
Kulesza S., Belej M.
Acta Physica Polonica A
|
2015
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vol. 127
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issue 3A
A-99-A-102
EN
The paper deals with time series of housing prices on local real estate markets in Warszawa (WAW), Kraków (KRK) and Poznań (POZ) from 2006 to 2013 using a model of critically-damped harmonic oscillator to study underlying system dynamics. Performed analysis reveals the presence of housing bubble in 2007 that emerge from otherwise quasi-regular evolution around the equilibrium state. Time series of housing prices are fitted numerically to estimate important parameters of the system, for example: decay constant, delay time, and price equilibrium level, which help us to chose the leading market. Obtained results show reasonable matching of the model with housing prices in WAW and POZ, but less in KRK. The latter data, however, are found to agree well with the model of under-damped harmonic oscillator, which actually suggests that some trembling might occur in that market. Nevertheless, local real estate markets can be thought of as a system of interconnected damped harmonic oscillators with leading market in WAW that is about to change under aggregate macroeconomic fluctuations (exogenous factors) triggering changes in remaining markets.
4
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Application of Fractal Analysis Methods for Lift Height Optimization in Magnetic Force Microscopy Measurements

81%
Bramowicz M., Kulesza S., Chrostek T., Senderowski C.
Archives of Metallurgy and Materials
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2018
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vol. 63
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issue 3
5
Content available remote

Structural Studies of Welds in Wear-Resistant Steels

81%
Bramowicz M., Kulesza S., Lewalski P., Szatkowski J.
Acta Physica Polonica A
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2016
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vol. 130
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issue 4
963-965
EN
The work presents results of the research on changes in microstructural, and mechanical properties of the structural XAR 400 wear-resistant steel caused by the welding procedure. Metallographic and microhardness studies revealed complex microstructure of the welds that turned out to vary with the distance from the weld axis: predominance of the acicular ferrite (ACF) structures in the weld itself, quasi-polygonal ferrite (QPF) crystals with precipitates of troostite (T) in the heat-affected zone, and the bainitic ferrite (BF) structures in the heat-partially-affected zone.
6
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Application of the Autocorrelation Function and Fractal Geometry Methods for Analysis of MFM Images

81%
Czaja P., Bramowicz M., Kulesza S., Maziarz W.
Archives of Metallurgy and Materials
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2014
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issue 2
7
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Analysis of the Surface Microtexture of Sputtered Indium Tin Oxide Thin Films

72%
Ţălu Ş., Kulesza S., Bramowicz M., Stępień K., Dastan D., Ţălu Ş., Kulesza S., Bramowicz M., Stępień K., Dastan D.
Archives of Metallurgy and Materials
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2021
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vol. 66
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issue 2
8
Content available remote

Surface Morphology Analysis of Composite Thin Films based on Titanium-Dioxide Nanoparticles

71%
Ţălu Ş., Bramowicz M., Kulesza S., Pignatelli F., Salerno M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 6
1529-1533
EN
This study addressed the advanced micro-morphological characterization of 3D surfaces of thin films based on composites of an organic matrix of poly-methyl-methacrylate and inorganic titanium-dioxide nanocrystals. The films were prepared by spin-coating of a series of solutions with increasing loading concentration of the nanocrystals, from 5 up to 40% by weight. The film surfaces were investigated by atomic force microscopy, and the resulting images were analyzed in detail to obtain a full quantitative description of their surface micro-morphology. The fractal analysis of the surface roughness was used to extract the characteristics of amplitude, spatial distribution, and pattern. A fractal geometry was indeed observed, and the corresponding fractal dimension D was determined for all the samples. In view of the possible use of these thin films as functional coatings, the calculated quantities are discussed with respect to the foreseen durability of these surfaces during operation under wear.
9
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Structural aging and degradation of human fingernail plates upon cosmetic agents

71%
Kulesza S., Bramowicz M., Gwoździk M., Wilczyński S., Goździejewska A. M.
Archives of Metallurgy and Materials
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2019
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vol. 64
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issue 1
10
Content available remote

Application of Atomic Force Microscopy for Studies of Fractal and Functional Properties of Biomaterials

62%
Kulesza S., Bramowicz M., Czaja P., Jabłoński R., Kropiwnicki J., Charkiewicz M.
Acta Physica Polonica A
|
2016
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vol. 130
|
issue 4
1013-1015
EN
The paper presents results of numerical analysis of AFM images of a surface of sandblasted Ti6Al7Nb alloys before and after wet etching procedure usually used for preparing commercially viable dental implants. Obtained results demonstrate that etching procedure efficiently cleans the implants as it leaves almost pure Ti-Al-Nb surface with trace amounts of alkali metals and increased hydrophobicity. Apart of that, it turned out that simple statistical measures of the height variations (root mean square roughness) only slightly change upon the treatment procedure, especially for scan lengths below 20 μm. On the other hand, correlation analysis exhibits bifractal surface patterns composed of regular residues left on otherwise helical ridges of the base material. Etching leaves its fingerprint in fractal dimension, but not in the corner frequency.
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