This paper describes the researches upon the precise short-time GPS solutions made in the Centre of Applied Geomatics, Military University of Technology. The data from ASG-EUPOS (Polish Active Geodetic Network) was processed using Bernese 5.0 software and EPN (EUREF Permanent Network) standards and models. In this study, the adopted 3-hour observation window is shifted every hour obtaining geocentric coordinates in ITRF2005 reference frame. The adjusted network consisted of over 130 stations from Poland and the neighbouring countries, the period covered observations collected from 8.06.2008 to 18.06.2010. These two years of observations allowed to examine short-period oscillations which we found as closely related to the tidal (dynamic) frequencies. The analysis of the residua from IERS2003 tidal model was performed using least squares method with the Eterna software upon the idea of Chojnicki. It confirmed existence of the significant energy in the frequencies corresponding to S1, K1 and K2. The effects in S1 frequency reflect thermal influences, but the reasons of K1 and K2 existence could be both: dynamic (liquid core resonance and non-linearity of K1 are very difficult for modelling as well as the annual modulation of S1) or artificial (GPS satellites’ orbiting period, dynamic changes of satellites’ constellation and network geometry, multipath, residual tropospheric and ionospheric errors etc.). Since the phase of K1 for all 130 sites is very inconsistent the local effects could be also taken into account as one of the possible reasons. The paper describes the idea of the data processing and analysis, presents the results of vertical (Up component) oscillations in main tidal frequency bands, but also includes the discussion on the possible explanation of existence of short period oscillations in GPS precise solutions., Janusz Bogusz and Jan Hefty., and Obsahuje bibliografii
Laser observations were performed in Borowiec in three years 1977-79 of the satellites Geos A and Geos C. These data were processed by means of the program ORBITA and stations coordinates were calculated by dynamical method. Another solution was found with the processing by the program GRIPE of SAO. These two dynamical solutions are compared with the translocation solution Wettzel-Borowiec.
Five methods for determination of the resonant frequencies of the flexural vibration of a sample are shown. A simplified differential partial equation is used to estimate the values of the frequencies. For an unknown sample the Lissajous figure method as well as the method using different lengths of samples are most suitable. For samples with a known elastic behaviour a comparison of the fundamental mode and the 1st overtone frequencies can be used or a calculation of the resonant frequency from the dimensions and the known Young’s modulus can be made. and V článku je uvedených päť metód na určovanie rezonančnej frekvencie ohybového kmitania vzorky. Na určenie frekvencií je použitá zjednodušená parciálna diferenciálna rovnica. Pre neznámu vzorku a materiál je najvhodnejšou metódou na určenie rezonančných frekvencií metóda Lissajousových obrazcov. Pre vzorky so známym modulom pružnosti môže byť použité porovnanie frekvencií základného a prvého módu, alebo výpočet rezonančnej frekvencie pomocou vzoriek rôznych rozmerov.
Using synthetic data we study the possibility of determining 1-D velocity models of the upper crust from P- and S-wave arrival times in the case of a narrow depth interval of seismic sources and sparse distribution of stations. The test is tailored to a similar real situation in one subregion of the western part of the Corinth Gulf, Greece. Two kinds of models are studied: (i) models composed of layers with constant velocity gradients, and (ii) models composed of homogeneous layers. To derive the structural models from arrival times, the Neighbourhood Algorithm of Sambridge (1999) is used, combined with the grid search for source locations. Weighted P- and S-wave arrival time residuals are used as the misfit function. Accurate and perturbed synthetic arrival times are used. The velocities at medium depths, with a fast velocity increase, are well determined in both models for the accurate data. However, the determination of velocity is less certain in the uppermost 5 km for the gradient model, and in the deepest layer for the model composed of homogeneous layers for the perturbed data. The presence or absence of hypocentres in the uppermost or in the second layer influences notably the obtained velocity in these layers in both models., Jaromír Janský, Vladimír Plicka and Oldřich Novotný., and Obsahuje bibliografii
In this article a method is presented to find systematically the domain of attraction (DOA) of hybrid non-linear systems. It has already been shown that there exists a sequence of special kind of Lyapunov functions Vn in a rational functional form approximating a maximal Lyapunov function VM that can be used to find an estimation for the DOA. Based on this idea, an improved method has been developed and implemented in a \textit{Mathematica}-package to find such Lyapunov functions Vn for a class of hybrid (piecewise non-linear) systems, where the dynamics is continuous on the boundary of the different regimes in the state space. In addition, a computationally feasible method is proposed to estimate the DOA using a maximal fitting hypersphere.
In this paper, we study the problem of finding deterministic (also known as feedback or closed-loop) Markov Nash equilibria for a class of discrete-time stochastic games. In order to establish our results, we develop a potential game approach based on the dynamic programming technique. The identified potential stochastic games have Borel state and action spaces and possibly unbounded nondifferentiable cost-per-stage functions. In particular, the team (or coordination) stochastic games and the stochastic games with an action independent transition law are covered.
Vysvětlíme tři hlavní významy slova chaos: v běžné řeči, v řecké mytologii a v teorii dynamických systémů. Dále se soustředíme na deterministický chaos jako typ chování nelineárních dynamických systémů. Uvedeme definice a vysvětlíme základní pojmy a budeme diskutovat vlastnosti a důsledky chaotických řešení. Uvedeme kvantitativní kritérium pro odlišení náhodných a deterministických systémů. Na závěr zmíníme souvislosti mezi deterministickým chaosem a výtvarným uměním., Pavel Pokorný., and Obsahuje seznam literatury
Tento text se věnuje nárůstu mimomanželské plodnosti v České republice. V úvodu připomíná, že současná sociologie nabízí dvě vysvětlení, proč k tomuto trendu dochází. Prvním je tzv. teorie druhého demografického přechodu a druhým odkaz na zneužívání sociálních dávek. Tento článek nabízí další vysvětlení, proč se zvyšuje podíl žen, které rodí děti mimo manželství, a to zvláště mezi matkami s nízkým vzděláním. Data Sociální a ekonomické podmínky mateřství totiž naznačují, že rostoucí mimomanželskou plodnost je možné do značné míry připsat osamělému mateřství, a to zvláště v nižších sociálních vrstvách. V posledním sledovaném období neměla v době porodu stálého partnera již více než polovina matek se základním vzděláním; muži se základním vzděláním mají rovněž po rozchodu s partnerkou velmi omezené kontakty se svými dětmi., Dana Hamplová., 6 tabulek, and Obsahuje bibliografii