Search

Start Over Format svazek Date Unknown

31093. Validation of approximation techniques for local total electron content mapping

Creator:
Krypiak-Gregorczyk, Anna, Wielgosz, Pawel, Gosciewski, Dariusz, and Paziewski, Jacek
Format:
print, bez média, and svazek
Type:
article, články, model:article, and TEXT
Subject:
Geologie. Meteorologie. Klimatologie, ionosféra, ionosphere, GNSS, ionospheric delay, TEC, 7, and 551
Language:
English
Description:
The aim of this study was to assess the performance of several approximation techniques for ionospheric total electron content (TEC) mapping. Approximation techniques based on data-fitting with local or general two-dimensional polynomials, local planes or distance-dependent interpolation were applied and tested. For the ionosphere modeling, dual-frequency GPS data from Polish GBAS system (ASG-EUPOS) were used, and TEC was estimated together with hardware delays from phasesmoothed pseudoranges. Next, grids of vertical TEC values with spatial resolution of 0.25 degrees in both latitude and longitude were generated using the evaluated approximation techniques. Subsequently the grids were used to create regional TEC maps with 5-minute temporal resolution, and also to create ionospheric delay corrections for GPS positioning. The quality of the resulting ionospheric maps was tested twofold, firstly by comparison to high-quality CODE global ionosphere maps (GIM), which were generated using data from about 150 GPS sites of the International GNSS Service (IGS). Secondly, by creating double-differenced ionospheric delay corrections and comparing them to reference values derived from the reference network data processing. For the correction tests, two perpendicular baselines directed North-South (N-S) and West-East (W-E) and reaching up to 100 km were selected. The approximation methods were analyzed with a special emphasis on the diverse ionospheric conditions. For the testing, a quiet ionosphere day of 20 March 2012 and an active ionosphere day of 9 March 2012 were selected. The results show that the regional models properly represent the changing ionosphere, with the best results provided by data-fitting into local functions., Anna Krypiak-Gregorczyk, Pawel Wielgosz, Dariusz Gosciewski and Jacek Paziewski., and Obsahuje bibliografii
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

31094. Validation of transport and friction formulae for upper plane bed by experiments in rectangular pipe

Creator:
Matoušek, Václav, Krupička, Jan, and Picek, Tomáš
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
sediment transport, sheet flow, bed load, and suspended load
Language:
Slovak
Description:
The paper describes results of validation of authors' recently proposed formulae for sediment transport and bed friction in the upper plane bed regime using laboratory experiments in a pressurized pipe. Flows of mixture of water and fine to medium ballotini (d50 = 0.18 mm) were observed in a rectangular pipe (51 x 51 mm) with a deposit at the bottom of the pipe. A comparison of test results with transport-formula predictions shows a satisfactory match confirming a good prediction ability of the proposed transport formula at high bed shear. A prediction ability of the friction formulae appears to be less convincing but still reasonable. A joint use of the formulae for transport and friction predicts the delivered concentration of transported sediment within the accuracy range of ± 40 per cent for flows in which transported sediments strongly affect the bed friction, i.e. for flows with delivered concentration of sediment higher than say 3 per cent.
Rights:
http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public

31095. Validita merania: hľadanie dôvodov absencie konsenzu

Creator:
Ropovik, Ivan
Format:
print, bez média, and svazek
Type:
article, předběžná sdělení, model:article, and TEXT
Subject:
Psychologie, psychologie, kauzalita, causality, validita, konsenzus, meranie, validity, consensus, measurement, 17, and 159.9
Language:
Czech
Description:
Príspevok sa zaoberá analýzou konceptu validity a hľadaním dôvodov absencie konsenzu v jej definovaní a vnímaní. Najvýznamnejšie koncepcie validity sú konfrontované z diachronického hľadiska s dôrazom na konceptuálne a epistemologické otázky. Táto analýza naznačuje, že rozdiely medzi jednotlivými koncepciami validity nie sú terminologickými hrami, ale majú vecné dôsledky. Zároveň je demonštrované, že význam aj tej najužšej a najčastejšie uvádzanej definície (test je validný, ak meria to, čo má merať) závisí na niekoľkých voľbách, ktoré sú v zásade arbitrárne. Tie následne implikujú empirické postupy potrebné pre atribúciu prívlastku „validný“ a v konečnom dôsledku aj to, či by mala byť validita považovaná za relačný alebo kauzálny koncept., The article discusses the concept of validity and explores the reasons for the absence of a widespread consensus in its definition and perception. Applying a diachronic perspective, the most influential conceptions of validity are being confronted with an emphasis on both conceptual and epistemological issues. Based on that analysis, it is argued that differences between several conceptions of validity are not just a terminological quibble. Furthermore, it is demonstrated that the meaning of even the simplest and mostly cited definition (a test is valid if it measures what it purports to measure) depends on some choices that are in fact arbitrary. These choices made further imply the epistemological procedures needed for the attribution of the "validity" label and whether validity should be considered a relational or a causal concept., Ivan Ropovik., and Obsahuje seznam literatury
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

31096. Validity of language sample measures taken from structured elicitation procedures in Czech

Creator:
Smolík, Filip and Seidlová-Málková, Gabriela
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
průměrná délka výpovědí, vývoj jazyka, komplexnost vět, osvojování gramatiky, mean lenght of utterance, language development, sentence complexity, and grammar acquisition
Language:
Czech
Description:
Validita řečových vzorků získaných strukturovanými elicitačními procedurami v češtině Některé standardizované diagnostické metody pro vyšetření slovní zásoby se opírají o to, jaké děti definují zadaná slova. Tato studie použila definice, které děti (N=135) poskytly v subtestu slovník z WPPSI, k prozkoumání strukturních vlastností jejich jazykové produkce. Při analýze byly použity metody analýzy řečových vzorků, přičemž cílem bylo testovat validitu indexů řečových vzorků jako je průměrná délka věty (MLU). Výsledky dokládají, že řečové vzorky získané během standardizovaných testových interakcí lze použít jako data pro analýzu, i když neposkytují tak bohatý zdroj informací jako vzorky získané ve spontánní interakci. MLU vykazovalo statisticky významkou korelaci se skóry porozumění syntaxi z testu TROG a z experiementálního testu ohýbání slov v produkci. Průměrný výskyt tvarů slovesa být v jedné větě vykazoval ještě silnější souvislost s testy gramatického vývoje než MLU. Korelace mezi indexy získanými z řečových vzorků a testy gramatického vývoje byly obecně poměrně nízké (kolem 0.3), ale vzhledem k počtu probandů vysoce statisticky významné. Potvrdilo se tak, že MLU a další indexy řečových vzorků jsou citlivými měřítky gramatického vývoje v češtině. and Objectives. Test the use of language samples elicited during the presentation of standardized psychometric methods for the diagnostics of language development using methods for language sample analysis. Validate the use of Mean Length of Utterance (MLU) against standardized measures of grammatical development in a sample of children of the same age. Subjects and settings. Total of 135 children aged on average 72.2 months (SD=3.7) participated. Linguistic productions of the children during the administration of the WPPSI vocabulary subtest were analyzed. This language sample was used for calculating the MLU and other indices. Additionally, children were administered Czech adaptations of standardized tests of grammatical development: TROG-2 for sentence comprehension and a test of morphological production. Hypotheses. MLU and other sample-derived indices should show significant relationships between the test measures of grammatical comprehension and production. Statistical analyses. Correlations, linear regression models. Results. There were signficant relationships between MLU and the tests of grammar comprehension and morphological production. The number of be-forms and prepositions per utterance were also related to the grammar tests. MLU was independently predicted by both grammar comprehension and the production of grammatical morphology. The results show validity of MLU in a sample of same-age children, which is rare in the available literature. Study limitations. The language samples provided by children’s definitions differed widely in size and style, which may underestimate the relationships between MLU and grammatical test measures.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

31098. Válka jako stav provizoria (Na příkladu Čechů ve Francii 1914-1918: František Kupka, Otto Gutfreund)

Creator:
Brouček, Stanislav
Format:
bez média and svazek
Type:
model:article and TEXT
Subject:
emigration, Czechs in France, František Kupka, Otto Gutfreund, and resistance movement abroad
Language:
Czech
Description:
The war turned the Czechs living in France (i.e. the citizens of Austrian-Hungary) into the enemies of France. Formation of Nazdar, a Czech volunteer company within the French foreign legion, became a way out of the situation. It was the painter František Kupka who was the chief of the Paris colony from the beginning of 1915. The sculptor Otto Gutfreund took part in the “rebellion” of Czech volunteers against demeaning conditions in the legion. In 1916, he was sent to a concentration camp. The end of the war reached both artists as being rather sceptical. The war affected their private lives and artistic works, and formed their relation to the French and the domestic Czech environment after 1918. The contribution compares their individual choice in reaction to the makeshift arrangement as well as how they overcame the necessity to be soldiers. The text is based mainly on correspondence between both artists and other archival materials.
Rights:
http://creativecommons.org/publicdomain/mark/1.0/ and policy:public

Limit your search

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »

Show values starting with
more »