This paper presents the concept of computer simulating model for robot-environment behaviour study and control. The modelling is aimed to particullar physical implementation of fourlegged robot. The schema of simulating model includes four main sub-models: environment-robot interaction, sensory data processing, robot action planning and action executing. Forward and inverse kinematics of robot is also mentioned. Described model was used for the development and testing of control gait algorithm for irregular terain. Further, arbitrary other action planning algorithm can be engaged in the model. and Obsahuje seznam literatury
Extensive lowland floodplains cover substantial parts of the glacially formed landscape of Northern Germany. Stream power is recognized as a force of formation and development of the river morphology and an interaction system between channel and floodplain. In order to understand the effects of the river power and flood power, HEC-RAS models were set up for ten river sections in the Upper Stör catchment, based on a 1 m digital elevation model and field data, sampled during a moderate water level period (September, 2011), flood season (January, 2012) and dry season (April, 2012). The models were proven to be highly efficient and accurate through the seasonal roughness modification. The coefficients of determination (R2 ) of the calibrated models were 0.90, 0.90, 0.93 and 0.95 respectively. Combined with the continuous and long-term data support from SWAT model, the stream power both in-channel and on the floodplain was analysed. Results show that the 10-year-averaged discharge and unit stream power were around 1/3 of bankfull discharge and unit power, and the 10-year-peak discharge and unit stream power were nearly 1.6 times the bankfull conditions. Unit stream power was proportional to the increase of stream discharge, while the increase rate of unit in-channel stream power was 3 times higher than that of unit stream power on the floodplain. Finally, the distribution of the hydraulic parameters under 10-years-peak discharge conditions was shown, indicating that only 1-10% of flow stream was generated by floodplain flow, but 40-75% volume of water was located on the floodplain. The variation of the increasing rate of the stream power was dominated by the local roughness height, while the stream power distributed on the floodplain mainly depended on the local slope of the sub-catchment.
We describe simulation approaches suitable for the full probabilistic reliability assessment of a concrete beam by the finite element method. We compare the direct Monte Carlo method with a variance reduction technique based on Importance Sampling. A material model for the concrete beam is presented. The obtained results of the reliability assessment are discussed. and Obsahuje seznam literatury
Oxidation kinetics of celulose, lignin, brown coal, and their mixtures were investigated. Using non-linear regression method kinetic parameters from thermogravimetric curves were calculated for oxidation of volatile matter and fixed carbon (char). The presence of the cellulose in the mixture affects the rate constant of lignin and brown coal oxidation which was determined by means of Arrhenius plots., Petr Šušák, Silvie Vallová and Juraj Leško., and Obsahuje bibliografii
The potential impact of climate change on the mean monthly runoff in the upper Hron River basin, which was chosen as a representative mountainous region in Central Slovakia, was evaluated. A conceptual hydrological balance model calibrated with data from the period 1971-2000 was used for modelling changes in runoff with monthly time steps. Changes in climate variables in the future were expressed by two different climate change scenarios developed within the framework of the CECILIA (Central and Eastern Europe Climate Change Impact and Vulnerability Assessment) project. The climate change scenarios were constructed using the pattern scaling method from the outputs of transient simulations made by 2 GCMs - ECHAM4/OPYC3 and HadCM2 (Dubrovský et al., 2005). The runoff change scenarios for the selected basin in the future time horizons of 2025, 2050 and 2100 show changes in the runoff distribution within a year. Changes in the seasonal runoff distribution were compared with previous results (Danihlík et al., 2004), which were achieved with climate change scenarios developed from the outputs of the CCCM97 and GISS98 global circulation models. and Článok sa zaoberá skúmaním vplyvu možnej zmeny klímy na sezónne rozdelenie odtoku na povodí horného Hrona. Na modelovanie priemerných mesačných prietokov bol použitý koncepčný model hydrologickej bilancie v mesačnom kroku, s parametrami kalibrovanými na referenčné obdobie 1971-2000. Zmeny klimatických charakteristík boli vyjadrené podľa 2 klimatických scenárov, spracovaných pre povodie horného Hrona v rámci projektu 6 RP CECILIA (Central and Eastern Europe Climate Change Impact and Vulnerability Assessment). Klimatické scenáre boli spracované na základe výstupov tranzietných simulácií 2 globálnych cirkulačných modelov ECHAM4/OPYC3 a HadCM2 (Dubrovský et al., 2005) pre budúce časové horizonty 2025, 2050 a 2100. Podľa hydrologických scenárov priemerných mesačných prietokov možno v budúcnosti na povodí horného Hrona predpokladať zmeny sezónneho rozdelenia odtoku. Predpokladané zmeny sezónneho rozdelenia odtoku sú konzistentné s výsledkami dosiahnutými v predchádzajúcich prácach (Danihlík et al., 2004), v ktorých boli hydrologické scenáre odtoku na povodí horného Hrona spracované na základe klimatických scenárov, založených na výstupoch globálnych cirkulačných modelov CCCM97 a GISS98.
This paper deals with experiments and computational simulations of composite material with hyperelastic matrix and steel fibres; the main goal is to compa and Obsahuje seznam literatury
This article deals with the numerical simulation of intensity distribution of the magnetic field by means of the final elements method (FEM). The computational model describes the distribution normal and tangential components of magnetic field intensity at the front and the close vicinity of the front of the external probe of the method of the magnetic spot. The maximum value of the normal component of remanent intensity is 330 kAm-1 when the probe is placed at a distance of 2 mm from the surface. The maximum value of the tangential component of remanent intensity is 230 kAm-1 when the probe is placed at a distance of 2 mm from the material surface. The intensity values were achieved with a maximum current amplitude of 6.91 A. The calculation was determined of the shape and topography of magnetic spot, which will enable the optimisation of measurement. and Článek se zabývá numerickou simulací rozložení intensity magnetického pole pomocí metody konečných prvků. Výpočtový model popisuje rozložení normálové a tangenciální složky intensity magnetického pole metody magnetické skvrny pod čelem příložné sondy. Maximální hodnota normálové složky remanentní intensity je 330 kAm-1 ve vzdálenosti sondy 2 mm nad povrchem materiálu. Maximální hodnota tangenciální složky remanentní intensity je 230 kAm-1 ve vzdálenosti 2 mm nad povrchem materiálu. Hodnoty intensity byly simulovány pro maximální amplitudu proudu 6,91 A. Výpočet směřoval ke zjištění tvaru a topografie magnetické skvrny, které budou sloužit k optimalizaci měření.
Chlorophyll fluorescence serves as a proxy photosynthesis measure under different climatic conditions. The objective of the study was to predict PSII quantum yield using greenhouse microclimate data to monitor plant conditions under various climates. Multilayer leaf model was applied to model fluorescence emission from actinic light-adapted (F') leaves, maximum fluorescence from light-adapted (Fm') leaves, PSII-operating efficiency (Fq'/Fm'), and electron transport rate (ETR). A linear function was used to approximate F' from several measurements under constant and variable light conditions. Model performance was evaluated by comparing the differences between the root mean square error (RMSE) and mean square error (MSE) of observed and predicted values. The model exhibited predictive success for Fq'/Fm' and ETR under different temperature and light conditions with lower RMSE and MSE. However, prediction of F' and Fm' was poor due to a weak relationship under constant (R2 = 0.48) and variable (R2 = 0.35) light., E. Janka, O. Körner, E. Rosenqvist, C.-O. Ottosen., and Obsahuje bibliografii
Fluorescence parameters obtained during steady-state electron transport are frequently used to evaluate photosynthetic efficiency of plants. We studied the behaviour of those parameters as a function of irradiance-adapted fluorescence yields FS and F'M. Applied simulations showed that photochemical quenching evaluated by qP is greatly influenced by the steady-state fluorescence level (FS), and that its evolution is not complementary to non-photochemical quenching (qN). On the other hand, the relative photochemical and non-photochemical quenching coefficients (qP(rel) and qN(rel)) proposed by Buschmann (1995) represent better the balance between the energy dissipation pathways. However, these relative parameters are also non-linearly related when the FS level is varied. We investigated the application of a new parameter, the relative unquenched fluorescence (UQF(rel)) which takes into account the fraction of non-quenched fluorescence yield (FS), which is related to closed photosystem 2 reaction centres not participating in electron transport. By using computer simulations and real in vivo measurements, we found that this new parameter is complementary to qP(rel) and qN(rel), which may facilitate the use of PAM fluorescence as diagnostic tool in environmental studies. and P. Juneau, B. R. Green, P. J. Harrison.
The extreme rainfall events in Central and East Europe on August 2002 rise the question, how other basins would respond on such rainfall situations. Such theorisation helps us to arrange in advance the necessary activity in the basin to reduce the consequence of the assumed disaster. The aim of the study is to recognise a reaction of the Uh River basin (Slovakia, Ukraine) to the simulated catastrophic rainfall events from August 2002. Two precipitation scenarios, sc1 and sc2, were created. The first of them was based on August’s precipitation from Ybbs (Austria), the second one was based on precipitation from south Bohemia. The rainfall-runoff model HBV-light was used to simulate average daily discharge. Observed daily precipitation in each August during the period 1990-1999 was replaced by these two scenarios and the daily discharges were simulated in Lekárovce gauging station. Peak discharges were computed from the daily averages according to the empirical relationship. In last step, a selection of the best theoretical distribution function of the annual maximum discharge was done using Qmax data series from the period 1931-2001. and Extrémne zrážkové udalosti z augusta 2002 v strednej a východnej Európe vyvolali otázku, ako by na podobné zrážkové situácie reagovali iné povodia. Takéto teoretické simulácie poskytujú možnosť eliminovať dôsledky extrémnych hydrologických situácií. Cieľom tejto štúdie je poznať reakciu povodia rieky Uh (Slovensko, Ukrajina) na prípadnú katastrofickú zrážkovo-odtokovú situáciu, aká bola v auguste 2002. Pre simuláciu extrémnych zrážkovo-odtokových situácií boli vytvorené dva katastrofické scenáre sc1 a sc2. Prvý scenár bol určený na základe zrážkových úhrnov nameraných v Rakúska (Ybbs) a druhý na základe zrážkových úhrnov nameraných v južných Čechách počas augusta 2002. Na simuláciu priemerných denných prietokov bol použitý model HBV-light. Merané denné zrážky v každom mesiaci august počas obdobia 1990-1999 boli zmenené podľa týchto scenárov. Následne boli simulované priemerné denné prietoky v stanici Uh-Lekárovce modelom HBV-light. Vrcholové prietoky boli počítané z denných priemerov vzhľadom na odvodené empirické vzťahy. V poslednom kroku štúdie bola vybratá najvhodnejšia teoretická distribučná funkcia maximálnych ročných prietokov použitím ročných Qmax z obdobia 1931-2001.