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Worst scenario method and other approaches to uncertainty
Harasim, Petr
2009 - English
A great many problems in natural, technical, and social sciences can be solved by means of suitable mathematical models. Since the input data of mathematical models is uncertain, the output values are also encubered by uncertainty. It is our goal to evaluate the uncertainty of output data if the uncertainty of input data is somehow speci ed. Here, we con- ne ourselves only to a brief description of stochastic methods, a fuzzy set approach, and the worst scenario method. Metoda nejhoršího scénáře a jiné přístupy k nejistotě Problémy vznikající v přírodních, technických a společenských vědách lze řešit pomocí vhodných matematických modelů. Protože vstupní data těchto modelů jsou nejistá, nejisté jsou i výstupní hodnoty. Cílem je popsat nejistotu ve výstupních hodnotách, je-li nejistota vstupních dat nějakým způsobem specifikována. Zde se omezíme pouze na stručný popis stochastických metod, metod založených na pojmu fuzzy množina a metody nejhoršího scénáře.
Keywords:
worst scenario method; uncertain input data; probability; admissible set
Available at various institutes of the ASCR
Worst scenario method and other approaches to uncertainty
A great many problems in natural, technical, and social sciences can be solved by means of suitable mathematical models. Since the input data of mathematical models is uncertain, the output values ...
Modified semismooth Newton Method: Numerical example
Byczanski, Petr; Sysala, Stanislav
2009 - English
The modified semismooth Newton method is introduced in this contribution. The modification is based on a ``damping" in each Newton iteration. The damping coefficient are computed by a minimisation problem. The method is described on an abstract problem with the main convergence results. Then it is applied to solving an elasto-plastic problem with hardening and illustrated on a numerical example. V příspěvku je studována nehladká Newtonova metoda s tlumením. Metoda je popsána a její konvergence analyzována na abstraktní úloze. Pomocí zkoumané metody je řešena úloha elasto-plasticity. Některé teoretické výsledky jsou pak ilustrovány na numerickém příkladě.
Keywords:
Newton-like method; damping; elasto-plasticity
Available at various institutes of the ASCR
Modified semismooth Newton Method: Numerical example
The modified semismooth Newton method is introduced in this contribution. The modification is based on a ``damping" in each Newton iteration. The damping coefficient are computed by a minimisation ...
Thermal behaviour of selected Czech sandstones
Plevová, Eva
2009 - English
Selected Czech sandstone samples were determined by thermogravimetry (TG), differential thermal analysis (DTA) and FT- IR spectroscopy (FT-IR). These methods were used for determination of mineral composition in Czech sandstone samples. The texture and spatial orientation was determined by optical microscopy. Obtained data were confronted with data from thermomechanical analysis (TMA). Vybrané vzorky pískovců z českých lokalit byly zkoumány metodami termogravimetrcké analýzy (TG), diferenční termické analýzy a FT- IR spektroskopie pro získání přehledu o jejich minerálním složení. Texturní parametry byly zjišťovány pomocí optické mikroskopie. Získaná data byla konfrontována s výsledky termomechanické analýzy.
Keywords:
TG/DTA; Czech sandstone; thermomechanical analysis
Available at various institutes of the ASCR
Thermal behaviour of selected Czech sandstones
Selected Czech sandstone samples were determined by thermogravimetry (TG), differential thermal analysis (DTA) and FT- IR spectroscopy (FT-IR). These methods were used for determination of mineral ...
The windthrows in Šumava Mts caused by Kyrill hurricane and terrain features
Kolejka, Jaromír; Klimánek, M.; Mikita, T.; Svoboda, Jaroslav
2009 - English
Relationships between the windthrow origin and location on one hand and terrain features (slope, aspect, elevation,curvity etc.) on the other hand were geostatistically derived. While the impact of individual terrain features was statistically low, the complex terrain influence based in the terrain windthrow risk classes was statistically important. Relationships between the windthrow origin and location on one hand and terrain features (slope, aspect, elevation,curvity etc.) on the other hand were geostatistically derived. While the impact of individual terrain features was statistically low, the complex terrain influence based in the terrain windthrow risk classes was statistically important.
Keywords:
terrain; windthrows; GIS
Available at various institutes of the ASCR
The windthrows in Šumava Mts caused by Kyrill hurricane and terrain features
Relationships between the windthrow origin and location on one hand and terrain features (slope, aspect, elevation,curvity etc.) on the other hand were geostatistically derived. While the impact of ...
The solution of problems with the pure Neumann boundary conditions on the outer boundary
Kohut, Roman
2009 - English
The pure Neumann boundary value problem is solvable only if all the applied external forces are balanced which means that the resultants of all forces and their moments vanish. The disturbance of the condition of balanced forces causes divergence of the used iterative method. For obtaining some numerical results we must seek generalized solution and modify the numerical techniques. Problém s čistými Neumannovými okrajovými podmínkami je řešitelný pouze v případě, kdy použité vnější síly jsou v rovnováze. To znamená, že výsledná síla a momenty jsou nulové. Porušení podmínek rovnováhy vede k divergenci použitých iteračních metod. Pro získání nějakých numerických výsledku musíme hledat zobecněné řešení a modifikovat numerické postupy.
Keywords:
pure Neumann boundary conditions; numerical techniques; iterative method
Available at various institutes of the ASCR
The solution of problems with the pure Neumann boundary conditions on the outer boundary
The pure Neumann boundary value problem is solvable only if all the applied external forces are balanced which means that the resultants of all forces and their moments vanish. The disturbance of the ...
Verification of Recent-Stress-Strain in Czech part of Upper Silesian Coal basin
Ptáček, Jiří; Grygar, R.; Koníček, Petr; Souček, Kamil; Staš, Lubomír; Waclawik, P.
2009 - English
A stresss strain model of Variscan structural tectonic pattern in the Czech part of Upper Silesian Coal Basin (USCB) based on paleostress analyse have been interpreted. It was compiled used many of tectonic measurements of planar and linear elements and their comparison with the knowledge of dynamic development of Variscan body in a larger framework of Moravo Silesian zone. It was took account the influence of Alpine deformation due to Carpathian nappe. There were more stress tensor gauging realised in the region above all using hydrofrac and treated overcoring methods during last ten years. It’s becoming apparent that for information of recent stress fields is usable the interpretation of focus mechanisms of energetic significant seismic events, which were observed here more than ten years. The aim of project is the verification of recent stress strain state in the easternmost region of Czech part of USCB.
Keywords:
coal geology; underground coal mining; stress strain model
Available at various institutes of the ASCR
Verification of Recent-Stress-Strain in Czech part of Upper Silesian Coal basin
A stresss strain model of Variscan structural tectonic pattern in the Czech part of Upper Silesian Coal Basin (USCB) based on paleostress analyse have been interpreted. It was compiled used many of ...
Occurrence of coal near Erigavo (Republic Somaliland)
Konečný, Pavel; Oliwkiewicz-Miklasinska, M.
2009 - English
The occurrence of Jurassic to Miocene coal in Republic Somaliland was described in literature. Some coal samples were collected in 2007 near Erigavo. On the base of palynological analysis the Jurassic age is suggested for examined coal. Content of ash of tested sample was 71,24% so that the sample is classified as a carbonaceous siltstone. The reflectance of huminite is RN = 0,33 %. Based on this data the next geological investigation was recommended. The occurrence of Jurassic to Miocene coal in Republic Somaliland was described in literature. Some coal samples were collected in 2007 near Erigavo. On the base of palynological analysis the Jurassic age is suggested for examined coal. Content of ash of tested sample was 71,24% so that the sample is classified as a carbonaceous siltstone. The reflectance of huminite is RN = 0,33 %. Based on this data the next geological investigation was recommended. V Republice Somaliland byly v literatuře popsány výskyty uhlí jurského až miocenního stáří. V roce 2007 byly poblíž města Erigavo odebrány vzorky uhlí. Stáří sloje odpovídá, podle výsledků palynologické analýzy, svrchní Juře. Analyzované uhlí, respektive uhelný prachovec obsahuje přes 70% popela, odraznost vitrinitu Rn je 0,33%. Na základě zjištěných dat byl doporučen další, podrobnější průzkum uhelných nalezišť v této zemi.
Keywords:
coal; geology; Republic Somaliland
Available at various institutes of the ASCR
Occurrence of coal near Erigavo (Republic Somaliland)
The occurrence of Jurassic to Miocene coal in Republic Somaliland was described in literature. Some coal samples were collected in 2007 near Erigavo. On the base of palynological analysis the Jurassic ...
Our Blue Gene Experience
Jakl, Ondřej; Starý, Jiří
2009 - English
The paper describes our precious short-time opportunity to make some hands-on experience with the Bulgarian IBM Blue Gene/P system, where we tested the parallel scalability of our domain decomposition finite element solver on a greater number of processors and completed experiments with microstructure modelling of geocomposite materials. The tests showed that due to its relatively low computation/communication performance ratio this specific architecture may need optimizations of parallel codes to take advantage of its performance potential. Clanek popisuje cennou zkusenost autoru s bulharskym systemem IBM Blue Gene/P, kde na vetsim poctu procesoru testovali paralelni skalovatelnost vlastniho konecneprvkoveho resice, jenz vyuziva metody rozkladu oblasti, a take pocitali model mikrostruktury geokompozitnich materialu. Testy potvrdily, ze v dusledku relativne nizkeho pomeru vypocetniho a komunikacniho vykonu tato specificka architektura muze vyzadovat optimalizaci paralelnich kodu pro vyuziti jejiho vykonnostniho potencialu.
Keywords:
IBM Blue Gene/P; finite element solver; parallel scalability
Available at various institutes of the ASCR
Our Blue Gene Experience
The paper describes our precious short-time opportunity to make some hands-on experience with the Bulgarian IBM Blue Gene/P system, where we tested the parallel scalability of our domain ...
On the worst scenario metod: A modified convergence theorem nad its application to an uncertain differential equation
Harasim, Petr
2009 - English
We propose a theoretical framework for solving a class of worst scenario problems. The existence of the worst scenario is proved through the convergence of a sequence of approximate worst scenarios. The main convergence theorem modifies and corrects the relevant results already published in the literature. The theoretical framework is applied to a particular problem with an uncertain boundary value problem for a nonlinear ordinty differential equation with an uncertain coefficient. Navrhneme teoretický základ k řešení určité třídy problémů nejhoršího scénáře. Existenci řešení původního problému dokážeme pomocí posloupnosti aproximovaných nejhorších scénářů. Hlavní konvergenční věta modifikuje příslušné výsledky, již dříve publikované v literatuře. Navržený teoretický rámec potom aplikujeme na řešení problému s nelineární diferenciální rovnicí s nejistým koeficientem.
Keywords:
worst scenario problem; nonlinear differential equation; incertain input parameters
Available at various institutes of the ASCR
On the worst scenario metod: A modified convergence theorem nad its application to an uncertain differential equation
We propose a theoretical framework for solving a class of worst scenario problems. The existence of the worst scenario is proved through the convergence of a sequence of approximate worst scenarios. ...
Shading of Bézier Patches
Kolcun, Alexej; Bocek, J.
2009 - English
There are well known shading algorithms (Gouraud, Phong) for the surfaces shading. The problem is that such algorithms just approximate the real shading. Precise shading algorithms require the values of normal vectors at all points of rendered surface. Computation of normal vector for Cartesian and triangular parametric surfaces is presented in the paper.
Keywords:
Beziér patch; shading; normal vector surface
Available at various institutes of the ASCR
Shading of Bézier Patches
There are well known shading algorithms (Gouraud, Phong) for the surfaces shading. The problem is that such algorithms just approximate the real shading. Precise shading algorithms require the ...
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