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2402. Assessment of computational efficiency of numerical quadrature schemes in the isogeometric analysis
- Creator:
- Rypl, Daniel and Patzák, Bořek
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- isogeometric analysis, numerical quadrature, Gaussian quadrature, Bézier extraction, half-point rule, and exact B-spline quadrature rule
- Language:
- English
- Description:
- Isogeometric analysis (IGA) has been recently introduced as a viable alternative to the standard, polynomial-based finite element analysis. One of the fundamental performance issues of the isogeometric analysis is the quadrature of individual components of the discretized governing differential equation. The capability of the isogeometric analysis to easily adopt basis functions implies that high order numerical quadrature schemes must be employed. This may become computationally prohibitive because the evaluation of the high degree basis functions and/or their derivatives at individual integration points is quite demanding. The situation tends to be critical in three-dimensional space where the total number of integration points can increase dramatically. The aim of this paper is to compare computational efficiency of several numerical quadrature concepts which are nowadays available in the isogeometric analysis. Their performance is asessed on the assembly of stifness matrix of B-spline based problems with special geometrical arrangement allowing to determine minimum number of integration points leading to exact results. and Článek zahrnuje seznam literatury a na str. 257-259 Appendix
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2403. Assessment of empirical formulae for determining the hydraulic conductivity of glass beads
- Creator:
- Říha, Jaromír, Petrula, Lubomír, Hala, Mario, and Alhasan, Zakaraya
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- hydraulic conductivity, empirical formulae, porosity, and porosity function configuration
- Language:
- Slovak
- Description:
- Empirical formulae are often used in practice to quickly and cheaply determine the hydraulic conductivity of soil. Numerous relations based on dimensional analysis and experimental measurements have been published for the determination of hydraulic conductivity since the end of 19th century. In this paper, 20 available empirical formulae are listed, converted and re-arranged into SI units. Experimental research was carried out concerning hydraulic conductivity for three glass bead size (diameters 0.2 mm, 0.5 mm and 1.0 mm) and variable porosity. The series of experiments consisted of 177 separate tests conducted in order to obtain relevant statistical sets. The validity of various published porosity functions and empirical formulae was verified with the use of the experimental data obtained from the glass beads. The best fit was provided by the porosity function n3/(1–n)2. In the case of the estimation of the hydraulic conductivity of uniform glass beads, the best fit was exhibited by formulae published by Terzaghi, Kozeny, Carman, Zunker and Chapuis et al.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2404. Assessment of energy partitioning in PSII complexes using chlorophyll fluorescence: reviewing the different approaches toward the definition of a unified method
- Creator:
- Kornyeyev, D., Guadagno, C. R., and D’Ambrosio, N.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- fotosyntéza, photosynthesis, chlorophyll fluorescence, energy partitioning, photosystem II, 2, and 581
- Language:
- Multiple languages
- Description:
- Based on the examination and quantitative comparison of the approaches used to assess the energy partitioning in photosystem II, the unified method was proposed to calculate the contribution of the components of nonphotochemical quenching. and D. Kornyeyev, C. R. Guadagno, N. D’Ambrosio.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2405. Assessment of Facial Expressions in Product Appreciation
- Creator:
- Popa, M. C., Rothkrantz, L. J. M., Wiggers, P., and Shan, C.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- product emotions, facial expression analysis, geometric features, appearance features, unsupervised learning, and supervised learning
- Language:
- English
- Description:
- In the marketing area, new trends are emerging, as customers are not only interested in the quality of the products or delivered services, but also in a stimulating shopping experience. Creating and influencing customers' experiences has become a valuable differentiation strategy for retailers. Therefore, understanding and assessing the customers' emotional response in relation to products/services represents an important asset. The purpose of this paper consists of investigating whether the customer's facial expressions shown during product appreciation are positive or negative and also which types of emotions are related to product appreciation. We collected a database of emotional facial expressions, by presenting a set of forty product related pictures to a number of test subjects. Next, we analysed the obtained facial expressions, by extracting both geometric and appearance features. Furthermore, we modeled them both in an unsupervised and supervised manner. Clustering techniques proved to be efficient at differentiating between positive and negative facial expressions in 78\% of the cases. Next, we performed more refined analysis of the different types of emotions, by employing different classification methods and we achieved 84\% accuracy for seven emotional classes and 95\% for the positive vs. negative.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2406. Assessment of factors and conditions influencing bank stability of future lakes
- Creator:
- Spanilá, Tamara, Kudrna, Zdeněk, Vladislav John, Hartvich, Filip, and Chour, Vladimír
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Geologie. Meteorologie. Klimatologie, jezera, geodynamika, lakes, geodynamics, flooding of residual mining pits, dangerous geodynamic phenomena, stability of banks and slopes, 7, and 551
- Language:
- English
- Description:
- While including gradual long-term flooding of individual residual mining pits, the re-vitalization program of the Podkrušnohorská brown-coal basin area has to assure - beside general water quality standards - satisfactory stability level of future lake banks and their wider environment as required for safe usage of future water lakes. General assessment of factors and conditions influencing bank and/or slope stability of future lakes was realized within the frames of the Czech Republic Academy of Sciences grant project. The grant project solutions include a study of exogenous processes on localities where the mining has been terminated. Also, prognoses were developed on behaviour of future banks during flooding and subsequent operation of future lakes. The presented paper is focused on assessment of mayor factors that participate on initiation and intensity of the bank abrasion and sliding deformations., Tamara Spanilá, Zdeněk Kudrna, Vladislav John, Filip Hartvich and Vladimír Chour., and Obsahuje bibliografické odkazy
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2407. Assessment of genotypic variation in salt tolerance of early CIMMYT hexaploid wheat germplasm using photosynthetic capacity and water relations as selection criteria
- Creator:
- Ashraf, M. and Shahbaz, M.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- net photosynthetic rate, stomatal conductance, transpiration rate, and Triticum
- Language:
- Multiple languages
- Description:
- Twenty-five genotypes of early CIMMYT hexaploid wheat were screened for salt tolerance in a glasshouse experiment using photosynthetic capacity and water relation parameters as selection criteria. Under salt stress (150 mM NaCl) the genotypes Frontana, Norin-10, Mayo-54, Noreste-66, and Yaktana-54 excelled all other lines in shoot dry mass, and Na(20)TPP, Penjamo-62, Inia-66, Frontana, Siete Cerros, and Jaral-66 in grain yield per plant in both absolute and relative (percent of control) terms. Although net photosynthetic rate (PN) declined in all genotypes due to salt stress, it was not helpful in discriminating among genotypes according to salt tolerance. Similarly, no positive relationships of salt tolerance of the genotypes with stomatal conductance, leaf water potential, or turgor pressure were found. Every genotype used its own specific mechanism to tolerate salt stress. However, a large amount of variation in salt tolerance observed in 25 early CIMMYT wheat genotypes can be of considerable practical value for improving salt tolerance in the existing commercial hexaploid wheats. and M. Ashraf, M. Shahbaz.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
2408. Assessment of HRV after maximal exercise in trained postmenopausal women
- Creator:
- Orri, J. C, Hughes, E. M, Mistry, D. G, and Scala, A
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- menopauza, menopause, training intensity, cardioprotection, 14, and 612
- Language:
- English
- Description:
- Increased parasympathetic tone achieved with endurance training may provide cardioprotection after menopause. To compare heart rate variability (HRV) from rest through maximal exercise and recovery in trained postmenopausal women. Thirtysix postmenopausal women who self-reported training at either moderate (MOD; 3-5.9 METS; 58.9±4.4 year) or vigorous (VIG; >6 METS; 59.7±5.2 year) intensities participated. HRV was measured for 5 min in the supine position, in the last minute of the VO2max test and after 2 min of active recovery. HRV in MOD and VIG was compared using a factorial ANOVA with repeated measures on time. MOD and VIG responded similarly over the three time periods for root mean square of sequential deviations (rMSSD), and high (HF) and low frequency (LF) power (p>0.05). Maximal exercise lowered rMSSD (3.3±0.08 vs. 1.2±0.06) and lnLF (4.1±0.05 vs. 3.3±0.13) and increased lnHF (3.3±0.14 vs. 4.0±0.10; p<0.01) from resting. However, active recovery restored lnHF (3.3±0.11) and lnLF (4.1±0.08) from maximal values (p<0.01). Our findings suggest that moderate and vigorous exercise training may enhance HRV recovery following one bout of maximal exercise in older women., J. C. Orri, E. M. Hughes, D. G. Mistry, A. Scala., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2409. Assessment of models to predict surface subsidence in the Czech part of the upper Silesian coal basin - case study
- Creator:
- Jiránková, Eva, Waclawik, Petr, and Nemcik, Jan
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- longwall mining, surface subsidence, great depth, finite element method, and Knothe method
- Language:
- English
- Description:
- This case study presents the verification of two surface subsidence prediction models for longwall mining at depths greater than 400 m. The surface subsidence points were surveyed and compared for both models. The first model uses empirical calculations to predict the surface subsidence. This method is reliable for predicting surface subsidence at shallower depths. At present, however, coal mining has progressed to great depths. The second model is the 2-dimensional finite element method to predict surface subsidence. In contrast to the first method, this method is based on the regional parameters and uses the rock mass properties to evaluate surface subsidence for multi-seams at any depth. Results show that the finite element method gives a better approximation of the measured surface subsidence than the Knothe method. The maximum surface subsidence, which was determined by the FEM method, was used to adjust the extraction coefficient in the Knothe's method. The predicted value differs from the measured value by 8 %. The slope of the predicted subsidence trough was within the range of 2‒8 % from the surveyed subsidence. This case study proposes a procedure for using both models to successfully predict the surface subsidence.
- Rights:
- http://creativecommons.org/publicdomain/mark/1.0/ and policy:public
2410. Assessment of multi-GNSS precise orbit and clock products from different analysis centers based on precise point positioning
- Creator:
- Li, Weiguo and Kačmařík, Michal
- Format:
- print, bez média, and svazek
- Type:
- model:article and TEXT
- Subject:
- satelitní navigační systémy, satellite navigation systems, Multi-GNSS, precise products, Precise Point Positioning, IGS MGEX, RTKLIB, 7, and 551
- Language:
- English
- Description:
- Performance of 24h static Precise Point Positioning (PPP) solutions based on multi-GNSS precise satellite orbit and clock products from four analysis centers and seven various constellation combinations was studied to evaluate their quality and characteristics. Data from ten European and four Chinese GNSS stations and 152 days long period from year 2020 were processed. Obtained coordinates were firstly compared with those provided by IGS final weekly combined solution. In Europe, the best agreement with this reference product was reached by solutions including Galileo signals, namely by a combination of GPS+GLONASS+Galileo systems with a mean RMS of 11 mm. This situation was different in China where inclusion of Galileo always led to worse results and the best agreement was achieved by a combination of GPS+GLONASS systems. Although product provided by German Research Center for Geosciences (GFZ) could be selected as the best performing over Europe and product by Center for Orbit Determination in Europe (CODE) over China, differences between individual precise products were mostly at a minimal level. Secondly, coordinates repeatability over the processed period was computed in order to assess the positioning stability. In this regard, the lowest values in both horizontal and vertical direction were reached by GPS+GLONASS solutions. From the perspective of precise products, the repeatability results were dependent on the selected constellation where mainly a specific behavior of product from Wuhan University (WUM) for Galileo system was observed., Weiguo Li and Michal Kačmařík., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public