Number of found documents: 14983
Published from to

Laplacian preconditioning of elliptic PDEs: Localization of the eigenvalues of the discretized operator
Gergelits, Tomáš; Mardal, K.-A.; Nielsen, B. F.; Strakoš, Z.
2019 - English
This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of fluorescent particle concentration, see [6, 1, 3, 4, 5]. More precisely, we continue to look for an optimal bleaching pattern used in FRAP (Fluorescence Recovery After Photobleaching), being the initial condition of the Fickian diffusion equation maximizing a sensitivity measure. As follows, we define an optimization problem and we show the special feature (so-called complementarity principle) of the optimal binary-valued initial conditions. Available in digital repository of the ASCR
Laplacian preconditioning of elliptic PDEs: Localization of the eigenvalues of the discretized operator

This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of ...

Gergelits, Tomáš; Mardal, K.-A.; Nielsen, B. F.; Strakoš, Z.
Ústav informatiky, 2019

On the Optimal Initial Conditions for an Inverse Problem of Model Parameter Estimation - a Complementarity Principle
Matonoha, Ctirad; Papáček, Š.
2019 - English
This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of fluorescent particle concentration, see [6, 1, 3, 4, 5]. More precisely, we continue to look for an optimal bleaching pattern used in FRAP (Fluorescence Recovery After Photobleaching), being the initial condition of the Fickian diffusion equation maximizing a sensitivity measure. As follows, we define an optimization problem and we show the special feature (so-called complementarity principle) of the optimal binary-valued initial conditions. Available in digital repository of the ASCR
On the Optimal Initial Conditions for an Inverse Problem of Model Parameter Estimation - a Complementarity Principle

This contribution represents an extension of our earlier studies on the paradigmatic example of the inverse problem of the diffusion parameter estimation from spatio-temporal measurements of ...

Matonoha, Ctirad; Papáček, Š.
Ústav informatiky, 2019

Chemical and mineralogical analyses of plaster samples from State Castle Bečov
Slížková, Zuzana; Koudelková, Veronika; Kozlovcev, Petr; Šterner, Adam
2018 - Czech
Using chemical and microscopic analysis, it was determined that the analyzed sample of bedding mortar from the 13th century (Czech castle Bečov) is the air lime mortar with the quartz and silicate sand enriched by some content of slag grains. The internal plaster from the same building period of the castle was made using the lime-earthen mortar with predominantly silicate sand. The plaster contained an admixture of wood or plant particles, sawdust has been identified.\n\n Pomocí chemické a mikroskopické analýzy bylo určeno, že analyzovaný vzorek malty z 13. stol. je vápenná malta s převážně křemenným a silikátovým pískem a vnitřní omítka z 13. stol. byla provedena z malty vápenohliněné s převážně silikátovým plnivem. Omítka obsahuje příměs dřevěných či rostlinných částic, byly identifikovány piliny. Malta obsahuje kousky strusky. Keywords: chemical composition; survey; material characterization; binder; aggregate; historic plaster; historic render Available at various institutes of the ASCR
Chemical and mineralogical analyses of plaster samples from State Castle Bečov

Using chemical and microscopic analysis, it was determined that the analyzed sample of bedding mortar from the 13th century (Czech castle Bečov) is the air lime mortar with the quartz and silicate ...

Slížková, Zuzana; Koudelková, Veronika; Kozlovcev, Petr; Šterner, Adam
Ústav teoretické a aplikované mechaniky, 2018

Proposal for loading tests of bridges - simulation and laboratory experiments
Bayer, Jan; Urushadze, Shota; Černý, Miloš
2018 - English
A new dynamic load testing of bridges is proposed and theoretically investigated. A transient analysis of passing vehicle over a bridge in ANSYS and an analytical program in MATLAB for the transient solution of piecewise linear mechanical structures were developed to assess the effects of the proposed dynamic load on a bridge model. According to the first laboratory experiments, it seems that the proposed travelling impulse load could surpass some of the shortcomings and limitations of the currently applied methods of bridge testing. The investigation is a part of a project aimed at drive-by identification of dynamic properties of bridges and further experimental and analytical research will follow. Keywords: dynamic loading tests; transient analysis; vibrations; vehicle-bridge interaction Available at various institutes of the ASCR
Proposal for loading tests of bridges - simulation and laboratory experiments

A new dynamic load testing of bridges is proposed and theoretically investigated. A transient analysis of passing vehicle over a bridge in ANSYS and an analytical program in MATLAB for the transient ...

Bayer, Jan; Urushadze, Shota; Černý, Miloš
Ústav teoretické a aplikované mechaniky, 2018

Characterization of historical renders and plasters sampled from the Castle Freudenstein (also called Slikuv Castle), tower „Slikovka“, Ostroh nad Jachymovem (Zamecký vrsek u Jachymova)
Slížková, Zuzana; Frankeová, Dita; Koudelková, Veronika
2018 - Czech
SEM and SEM-EDS analyses was used for determination of renders and plasters microstructure and components Vzorky vnějších a vnitřních omítek byly zkoumány za účelem zjištění jejich struktury a chemického složení pomocí metod SEM a SEM-EDS Keywords: render; plaster; slag; cement; SEM-EDS analysis Available at various institutes of the ASCR
Characterization of historical renders and plasters sampled from the Castle Freudenstein (also called Slikuv Castle), tower „Slikovka“, Ostroh nad Jachymovem (Zamecký vrsek u Jachymova)

SEM and SEM-EDS analyses was used for determination of renders and plasters microstructure and components

Slížková, Zuzana; Frankeová, Dita; Koudelková, Veronika
Ústav teoretické a aplikované mechaniky, 2018

Footbridge in Radotín - wind load according to EN 1991-1-4 and wind tunnel experiments
Göringer, J.; Hračov, Stanislav; Macháček, Michael
2018 - Czech
Due to the atypical design of the footbridge in Radotín the procedures for evaluation of the force coefficients presented in EN 1991-1-4 were experimentally verified in the wind tunnel. For the lack of the information about the structure behaviour on the edge of the aerodynamic instability the critical velocity for flutter was experimentally verified as well. The paper presents comparison of the approaches from EN 1991-1-4 with the results of the experiment. S ohledem na atypickou konstrukci lávky v Radotíně bylo nutno v rámci statického ověření řešit nestandardní účinky zatížení větrem, kdy EN 1991-1-4 poskytuje pro takto atypické konstrukce jen málo podpory. Zatížení větrem u takovéto konstrukce nevystupuje pouze jako náhradní statický účinek, ale zejména je nutné posoudit případné ztráty aerodynamické stability. Příspěvek předkládá postup stanovení problematiky podle EN 1991-1-4 včetně porovnání s výsledky z větrného tunelu. Keywords: wind load; footbridge; wind tunnel experiments Available at various institutes of the ASCR
Footbridge in Radotín - wind load according to EN 1991-1-4 and wind tunnel experiments

Due to the atypical design of the footbridge in Radotín the procedures for evaluation of the force coefficients presented in EN 1991-1-4 were experimentally verified in the wind tunnel. For the lack ...

Göringer, J.; Hračov, Stanislav; Macháček, Michael
Ústav teoretické a aplikované mechaniky, 2018

Tourist interest in illicit zone of ice caves
Nováková, Eva; Kuda, František; Kubalíková, Lucie
2018 - English
Ledové sluje (Ice Caves) in the Podyjí National Park represents one of the most spectacular sites within the area. It consists of the large boulder field and several pseudokarst caverns on the north-western slope of the ridge that are very important from the ecological and geomorphological point of view. The access to the site is restricted for the visitors of National Park as there exists a risk of damage and disturbance of these unique phenomena; tourist can use the marked paths leading around the site, they can reach the top part of the ridge.\nCurrently, there are only several persons who have legal access to the site (employees of the National Park Administration and other researches with the permission issued by NP Administration). However, the installed sensor that counts the passages proved that the site is visited more frequently than it should be. The number of people who visit this site (situated within the first zone of National Park where there is no marked path and so the access is forbidden by decree) is quite alarming. Based on these findings, some proposals for the solution of this unfavourable situation are proposed and other possibilities how to avoid this undesirable phenomenon are discussed.\n Keywords: Podyji National Park; restricted area; passages monitoring Available in a digital repository NRGL
Tourist interest in illicit zone of ice caves

Ledové sluje (Ice Caves) in the Podyjí National Park represents one of the most spectacular sites within the area. It consists of the large boulder field and several pseudokarst caverns on the ...

Nováková, Eva; Kuda, František; Kubalíková, Lucie
Ústav geoniky, 2018

Generation of Intermittent Jet by Pulse-Modulated Synthetic Jets
Broučková, Zuzana
2018 - English
An axisymmetric air jet was excited using a pair of counter synthetic jets running in opposed direction. First, the control synthetic jets were measured alone. The driving signal was pulse modulated sinusoidal signal. After an adjustment, the primary axisymmetric jet was excited to the bifurcating mode, and its behavior was studied experimentally. For comparison purposes, a reference steady (unforced) jet from the same nozzle was also measured (Reynolds number was approximately 1300). The flow visualization and hot-wire anemometry techniques were used. Keywords: synthetic jet; pulse modulation; flow control Available at various institutes of the ASCR
Generation of Intermittent Jet by Pulse-Modulated Synthetic Jets

An axisymmetric air jet was excited using a pair of counter synthetic jets running in opposed direction. First, the control synthetic jets were measured alone. The driving signal was pulse modulated ...

Broučková, Zuzana
Ústav termomechaniky, 2018

Deformometric and leveling measurements in the cadastral area of Dětmarovice village in 2018
Kajzar, Vlastimil
2018 - Czech
Institute of Geonics AS CR, v.v.i. in 2001, in connection with the underground mining of coal reserves and its possible influence on the cadastral area of ​​Dětmarovice, Ostrava was asked in 2001 to assess the possible impacts of undermining on the stability of slopes on selected parts of the cadastral territory of Dětmarovice. Consequences of the mining are, among other things, surface drops, which, due to the existing morphology of the terrain in the cadastral area in question, raised the concern that these declines would not further induce sloping movements.\nIn November 2001, a monitoring monitoring network of four individual profiles was built in the locality. On these lines it was recommended to perform deformometric (longitudinal) and leveling measurements at the same intervals. From the subsequent periodic deformometric and leveling monitoring of these slopes before the development of the descending basin into the monitored area and then during the period of manifestation of the effects of the mining, it is possible to determine whether the slope deformations develop at all and then to point out the possible causes of possible movements (morphological-geotechnical and climatic conditions, mining and anthropogenic activity, etc.). Ústav geoniky AV ČR, v.v.i. v Ostravě byl v souvislosti s uvažovaným hlubinným dobýváním uhelných zásob a jeho možného vlivu na katastrální území Dětmarovice požádán v roce 2001 Dolem ČSA o posouzení případných vlivů poddolování na stabilitu svahů na vybrané části katastrálního území Dětmarovice. Důsledkem dobývání jsou, mimo jiné, i poklesy povrchu, což vzhledem ke stávající morfologii terénu v předmětném katastrálním území vyvolalo obavu, zda tyto poklesy nebudou dále indukovat svahové pohyby.\nV listopadu 2001 tedy byla v dané lokalitě vybudována kontrolní monitorovací síť o čtyřech individuálních profilech. Na těchto přímkách bylo doporučeno provádět ve stejných intervalech deformometrická (délková) a nivelační (výšková) měření. Z následného periodického deformometrického a nivelačního monitoringu těchto svahů ještě před začátkem rozvoje poklesové kotliny do sledované oblasti a dále v období projevů účinků dobývání je pak možné stanovit, zda vůbec k vývoji svahových deformací dochází, a následně na možné příčiny případných pohybů poukázat (morfologicko-geotechnické a klimatické přírodní podmínky, hornická a antropogenní činnost aj.). Keywords: deformometric measuring; leveling measuring; Dětmarovice Available on request at various institutes of the ASCR
Deformometric and leveling measurements in the cadastral area of Dětmarovice village in 2018

Institute of Geonics AS CR, v.v.i. in 2001, in connection with the underground mining of coal reserves and its possible influence on the cadastral area of ​​Dětmarovice, Ostrava was asked in 2001 to ...

Kajzar, Vlastimil
Ústav geoniky, 2018

Two Algorithms for Risk-averse Reformulation of Multi-stage Stochastic Programming Problems
Šmíd, Martin; Kozmík, Václav
2018 - English
Many real-life applications lead to risk-averse multi-stage stochastic problems, therefore effective solution of these problems is of great importance. Many tools can be used to their solution (GAMS, Coin-OR, APML or, for smaller problems, Excel), it is, however, mostly up to researcher to reformulate the problem into its deterministic equivalent. Moreover, such solutions are usually one-time, not easy to modify for different applications. We overcome these problems by providing a front-end software package, written in C++, which enables to enter problem definitions in a way close to their mathematical definition. Creating of a deterministic equivalent (and its solution) is up to the computer. In particular, our code is able to solve linear multi-stage with Multi-period Mean-CVaR or Nested Mean-CVaR criteria. In the present paper, we describe the algorithms, transforming these problems into their deterministic equivalents. Keywords: Multi-stage stochastic programming; deterministic equivalent; multi-period CVaR; nested CVaR; optimization algorithm Fulltext is available at external website.
Two Algorithms for Risk-averse Reformulation of Multi-stage Stochastic Programming Problems

Many real-life applications lead to risk-averse multi-stage stochastic problems, therefore effective solution of these problems is of great importance. Many tools can be used to their solution (GAMS, ...

Šmíd, Martin; Kozmík, Václav
Ústav teorie informace a automatizace, 2018

About project

NRGL provides central access to information on grey literature produced in the Czech Republic in the fields of science, research and education. You can find more information about grey literature and NRGL at service web

Send your suggestions and comments to nusl@techlib.cz

Provider

http://www.techlib.cz

Facebook

Other bases