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Wyszukujesz frazę "longitudinal" wg kryterium: Temat


Tytuł:
The depositional conditions of longitudinal dunes based on investigations in the western part of the Lublin Upland, SE Poland
Autorzy:
Zieliński, P.
Powiązania:
https://bibliotekanauki.pl/articles/294306.pdf
Data publikacji:
2003
Wydawca:
Stowarzyszenie Geomorfologów Polskich
Tematy:
longitudinal dunes
date Pleistocene
Lublin Upland
Opis:
The development of longitudinal dunes depends on three overlapping factors: the strength and direction of winds, the amount of supplied sand, and the occurrence of vegetation which can fix the rising forms. It is assumed that longitudinal dunes in Polish territory were mainly formed from the arms of parabolic dunes, as a result of the deflation of the central parts of these dunes. However, it is possible that some longitudinal dunes in Poland could also have developed as primary forms. The detailed studies of longitudinal dunes in the western part of the Lublin Upland have revealed an important structural differentiation resulting from various development conditions of each particular form. Three models of development of longitudinal dunes are derived from these investigations: 1)  They are formed by undirectional winds deflating the central parts of parabolic dunes, when sand supply is small, and vegetation fixes the rising forms. 2)  They develop after a change of wind direction by 90°, in consequence of transformation of a single transversal dune or a set of parabolic dunes formed in front of or on an obstruction. 3)  They are primary forms originating at obstructions, when eolian material is transported by bidirectional winds from a narrow (up to 90°) sector.
Źródło:
Landform Analysis; 2003, 4; 65-73
1429-799X
Pojawia się w:
Landform Analysis
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On Parameter Estimation of Some Longitudinal Model
O estymacji parametrów pewnego modelu dla danych wielookresowych
Autorzy:
Żądło, Tomasz
Powiązania:
https://bibliotekanauki.pl/articles/905660.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Łódzki. Wydawnictwo Uniwersytetu Łódzkiego
Tematy:
longitudinal data
restricted maximum likelihood
MSE
Opis:
The problem of modeling longitudinal profiles is considered assuming that the population and elements’ affiliation to subpopulations may change in time. Some longitudinal model which is a special case of the general linear model (GLM) and the general linear mixed model (GLMM) is studied. In the model two random components are included under assumptions of simultaneous spatial autoregressive process (SAR) and temporal first-order autoregressive process (AR(1)) respectively. The accuracy of model parameters’ restricted maximum likelihood estimators is considered in the simulation.
Rozważany jest problem modelowania profili wielookresowych zakładając, że populacja i przynależność elementów domen mogą zmieniać się w czasie. Proponowany model jest przypadkiem szczególnym ogólnego modelu liniowego i ogólnego mieszanego modelu liniowego. W modelu tym uwzględniono dwa wektory składników losowych spełniające odpowiednio założenia przestrzennego modelu autoregresyjnego i modelu autoregresyjnego rzędu pierwszego w czasie. W symulacji rozważano dokładność estymatorów parametrów modelu uzyskanych metodą największej wiarygodności z ograniczeniami.
Źródło:
Acta Universitatis Lodziensis. Folia Oeconomica; 2013, 285
0208-6018
2353-7663
Pojawia się w:
Acta Universitatis Lodziensis. Folia Oeconomica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Specyfika i dynamika czasowa objawów dysfunkcji wykonawczych po udarze mózgu w świetle badań longitudinalnych
Specificity and time-course of post-stroke executive dysfunctions in light of the longitudinal study
Autorzy:
Jodzio, Krzysztof
Biechowska, Daria
Gąsecki, Dariusz
Szurowska, Edyta
Powiązania:
https://bibliotekanauki.pl/articles/1178574.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Kazimierza Wielkiego w Bydgoszczy
Tematy:
cerebral stroke
executive dysfunctions
longitudinal study
Opis:
Cerebral stroke is the very common cause of executive dysfunctions, such as disinhibition and inability to switch of attention. The aim of this longitudinal study was to determine a clinical characteristic of executive dysfunctions in light of the neuropsychological examinations. Forty-four patients who had ischemic stroke were examined twice with a twelve-month interval. At each session executive functions were measured on the same patients. Executive functioning was measured by three popular tasks, i.e. an experimental version of the Stroop Color- Word Interference Test, Verbal Fluency Test, and Trail Making Test. Twenty-five healthy volunteers were examined once only to transform patients’ results of neuropsychological testing into standardized form. Executive impairment was found in 24 patients (i.e. 65% of the clinical group), who failed to complete at least one of the three tests. Patients manifested executive dysfunctions which were highly heterogeneous with respect to character, severity and their prevalence. Overall, there was clear evidence that executive functions showed substantial recovery. Timecourse of distinct executive dysfunctions was similar.
Źródło:
Polskie Forum Psychologiczne; 2012, XVII, 2; 276-289
1642-1043
Pojawia się w:
Polskie Forum Psychologiczne
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of the Curvature of the Longitudinal Foot Arch in Children aged 7 and 8 – A Pilot Study
Autorzy:
Niewiadomska, Monika
Makris, Maria
Kotraska, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/1030507.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
child
longitudinal foot arch curvature
podoscope
Opis:
The foot is an essential part of the human body, and a key factor enabling mobility. The proper functioning of the foot depends on its morphological structure and on the proper shape of its arches – transversal and longitudinal. Having in mind that flat feet develop as a succession of different stages, it is important to systematically monitor the development of feet at various phases of a child’s growth. Therefore, this study aims to evaluate longitudinal foot arch curvature in children aged 7 and 8. The study involved 122 children (77 girls and 45 boys) aged 7 and 8 – students of a primary school in Bezrzecze near the city of Szczecin. Body height and weight, and the length and width of the feet were measured. A podoscope was used to determine the curvature of the longitudinal foot arch, which was then expressed on a scale compatible with the Szriter-Gudanow “KY” foot arch curvature index. This non-invasive method enables preventive measures to be taken at critical stages of a child’s life. The results for the tested groups of children revealed statistically significant relationships for body height and weight, and the length of the feet between the 7 and 8 year olds. Furthermore, it was observed that the vast majority of the tested children has normal curvature of the longitudinal arch of both the right and left foot.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2018, 21, 1; 31-40
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Overview of the research on roll forging processes
Autorzy:
Tofil, A.
Pater, Z.
Powiązania:
https://bibliotekanauki.pl/articles/101862.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
cross rolling
longitudinal rolling
helical rolling
Opis:
The paper overviews the research on roll forging processes in the last two decades. Given the broad scope of this problem, the overview focuses on processes in forging plants, omitting those performed in metallurgical plants. Three rolling processes are discussed in detail: longitudinal rolling, cross rolling and helical rolling. Each of the three techniques is discussed in terms of the main research problems and potential directions of future development.
Źródło:
Advances in Science and Technology. Research Journal; 2017, 11, 2; 72-86
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Graphical tools of discrete longitudinal data presentation in R
Autorzy:
Genge, Ewa
Powiązania:
https://bibliotekanauki.pl/articles/425116.pdf
Data publikacji:
2019
Wydawca:
Wydawnictwo Uniwersytetu Ekonomicznego we Wrocławiu
Tematy:
longitudinal data
categorical sequences
sequence visualization
Opis:
Good graphical presentation of data is useful during the whole analysis process from the first glimpse into the data to the model fitting and presentation of results. The most popular way of longitudinal data presentation are separate (for each wave, in cross-sectional dimension) comparisons of figures. However, plotting the data over time is useful in suggesting appropriate modeling techniques to deal with the heterogeneity observed in the trajectories. The main aim of this paper is to present the changing perceptions of the financial situation in Poland using different graphical tools for the heterogonous discrete longitudinal data sets and present demographics features for those changes. We will focus on the most important features of the categorical longitudinal data – category sequences and their graphical presentation. We aim to characterize the analyzed sequences on the basis of unidimensional indicators and composite complexity measures, as well as using mainly TraMineR [Gabadinho et al. 2017] package of R.
Źródło:
Econometrics. Ekonometria. Advances in Applied Data Analytics; 2019, 23, 3; 26-39
1507-3866
Pojawia się w:
Econometrics. Ekonometria. Advances in Applied Data Analytics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Sliding mode control for longitudinal aircraft dynamics
Autorzy:
Iskrenovic-Momcilovic, O.
Powiązania:
https://bibliotekanauki.pl/articles/385149.pdf
Data publikacji:
2018
Wydawca:
Sieć Badawcza Łukasiewicz - Przemysłowy Instytut Automatyki i Pomiarów
Tematy:
aircraft dynamics
control
elevator
longitudinal
sliding mode
Opis:
The control of the longitudinal aircraft dynamics is challenging because the mathematical model of aircraft is highly nonlinear. This paper considers a sliding mode control design based on linearization of the aircraft, with the pitch angle and elevator deflection as the trim variables. The design further exploits the decomposition of the aircraft dynamics into its short-period and phugoid approximations. The discrete-time variable structure system synthesis is performed on the base of the elevator transfer function short-period approximation. This control system contains a sliding mode controller, an observer, based on nominal aircraft model without finite zero and two additional control channels for the aircraft and for the aircraft model. The realised system is stable and robust for parameter and external disturbances.
Źródło:
Journal of Automation Mobile Robotics and Intelligent Systems; 2018, 12, 3; 55-60
1897-8649
2080-2145
Pojawia się w:
Journal of Automation Mobile Robotics and Intelligent Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An analysis of phugoid oscillations of unmanned flying wing
Autorzy:
Mioduska, P.
Powiązania:
https://bibliotekanauki.pl/articles/242816.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
UAV
flying wing
longitudinal stability
phugoid oscillations
Opis:
The flying wing configuration has been considered by airplane designers for more than one hundred years. Tailless aircraft have been inspired by nature and its solutions. In present times, this configuration is used to design Unmanned Aerial Vehicle (UAV). This type of plane could serve personal, military and research purposes. The flying wing is characterized by large amount of payload space, smaller wetted area than conventional airplane and stealth capability. This makes, that it is widely applicable in rescue operations, geodetic and cartographic research, monitoring of natural resources, taking pictures or videos. Despite all the merits of tailless plane, it also has its downsides. The main problem of this type of aircraft is longitudinal stability. A conventional airplane can compensate the pitch moment of the wing with its horizontal tail but a flying wing is tailless. A slow decay of oscillations amplitude is the problem, which can be solved by active control or proper aerodynamic design. A combination of geometric characteristic such as sweep, taper, twist and location of vertical stabilizers along span, can lead to stable flying wing. In this article, the results of phugoid oscillations analysis of unmanned flying wing are presented. Research platform was X8-2, popular flying wing UAV, designed for First Person View (FPV) method to control the vehicle. The calculations were performed using 3D panel method. On the basis of calculations for three versions of the model aircraft, the dynamic characteristics were created. The analysis of longitudinal stability undertaken here has indicated propriety of applied changes in geometry.
Źródło:
Journal of KONES; 2016, 23, 2; 247-254
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Reflection and transmission of plane waves between two different fluid saturated porous half spaces
Autorzy:
Kumar, R.
Miglani, A.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/202265.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
porous
amplitude ratios
reflection
transmission
longitudinal waves
Opis:
The present study is concerned with the reflection and transmission of plane waves between two different fluid saturated porous half spaces when longitudinal and transversal waves impinge obliquely at the interface. Amplitude ratios of various reflected and transmitted waves are obtained .The variations of amplitude ratios with angle of incidence are depicted graphically. A particular case of reflection at the free surface in fluid saturated porous half spaces has been deduced and discussed. A special case of interest has also been deduced from the present investigation.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2011, 59, 2; 227-234
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tracking the dynamic nature of learner individual differences: Initial results from a longitudinal study
Autorzy:
Jung, Daniel
DiBartolomeo, Megan
Melero-García, Fernando
Giacomino, Lindsay
Gurzynski-Weiss, Laura
Henderson, Carly
Hidalgo, Marian
Powiązania:
https://bibliotekanauki.pl/articles/780852.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
individual differences
longitudinal
cluster analysis
dynamicity
Spanish
Opis:
Individual differences (IDs) have long been considered one of the most important factors explaining variable rates and outcomes in second language acquisition (Dewaele, 2013). While traditional operationalizations of IDs have, explicitly or implicitly, assumed that IDs are static traits that are stable through time, more recent research inspired by complex dynamic systems theory (Larsen-Freeman, 1997, 2020) demonstrates that many IDs are dynamic and variable through time and across contexts, a theme echoed throughout the current issue. This study reports the initial semester of a diachronic project investigating the dynamicity of four learner IDs: motivation, personality, learning and cognitive styles, and working memory. In the initial semester, data from 323 participants in their first year of university-level Spanish were collected and analyzed to determine what type of variability may be present across learners with respect to the four IDs studied at one time point and to discern possible learner profiles in the data or patterns via which the data may be otherwise meaningfully described. The results revealed four types of learner profiles present in the dataset.
Źródło:
Studies in Second Language Learning and Teaching; 2020, 10, 1; 177-219
2083-5205
2084-1965
Pojawia się w:
Studies in Second Language Learning and Teaching
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental and numerical analysis of stick-slip suppression with the use of longitudinal tangential vibration
Autorzy:
Rybkiewicz, Marta
Gutowski, Paweł
Leus, Mariusz
Powiązania:
https://bibliotekanauki.pl/articles/2055033.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Tematy:
stick-slip phenomenon
longitudinal tangential vibrations
LuGre model
Opis:
The results of experimental tests and numerical simulation analyses of the possibility of partial reduction or entire elimination the stick-slip phenomenon in sliding motion through introduction of longitudinal tangential vibrations to the contact zone of a shifted body and the substrate are shown in the paper. The experimental tests were carried out on a specially designed stand. In the computational model, the dynamic equation of motion of the shifted body was used, and for the friction force description the LuGre model was adopted. A excellent consistency of the experimentally determined results with those calculated with the use of the developed model is obtained.
Źródło:
Journal of Theoretical and Applied Mechanics; 2020, 58, 3; 637--648
1429-2955
Pojawia się w:
Journal of Theoretical and Applied Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Experimental investigations of elimination the stick-slip phenomenon in the presence of longitudinal tangential vibration
Autorzy:
Leus, Mariusz
Abrahamowicz, Marta
Powiązania:
https://bibliotekanauki.pl/articles/386857.pdf
Data publikacji:
2019
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
stick-slip phenomenon
drive force
longitudinal tangential vibrations
Opis:
The article presents a scheme and description of the test stand as well as selected experimental results of the influence of longitudinal tangential vibrations on the stick-slip phenomenon. The tests were carried out at a constant forced vibration frequency f = 2000 Hz, as a function of the amplitude of the vibration velocity va. The position of the sliding body and the drive force necessary to make the body slip and maintain this motion were measured. The measurements were made in two successive stages. In the first stage, when the substrate on which the sliding occurred was stationary. In the second one, the substrate is in a vibrating motion in the direction parallel to the slip. The conducted experimental analyses have shown that longitudinal tangential vibrations can contribute to the reduction or even complete elimination of the stick-slip phenomenon.
Źródło:
Acta Mechanica et Automatica; 2019, 13, 1; 45-50
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Teoretyczny opis rozkładu rozpylonej cieczy w warunkach działania czołowego strumienia powietrza
Theoretical description of sprayed liquid distribution in conditions of frontal air stream operation
Autorzy:
Szewczyk, A.
Wilczok, G.
Powiązania:
https://bibliotekanauki.pl/articles/292134.pdf
Data publikacji:
2008
Wydawca:
Polskie Towarzystwo Inżynierii Rolniczej
Tematy:
opryskiwanie
rozpylacz
rozkład podłużny
spraying
sprayer
longitudinal distribution
Opis:
W pracy przedstawiono założenia modelowe i opracowano model matematyczny rozkładu podłużnego rozpylonej strugi odchylonej przez czołowy strumień powietrza tak jak to się dzieje w trakcie ruchu opryskiwacza. W wynikach badań przedstawiono również weryfikację opracowanego modelu w warunkach działania strumienia powietrza. Stwierdzono, że przyjęty model pozwala z dużym przybliżeniem określić rozkład opadu cieczy co potwierdziły wyniki przeprowadzonych badań laboratoryjnych.
The paper presents assumptions for the model and the developed mathematical model of longitudinal distribution of sprayed stream deflected by frontal air stream, as it happens while spraying machine is in motion. The test results also include verification of the developed model in conditions of air stream operation. It has been observed that the assumed model allows with a rough approximation to determine liquid fall distribution, which has been confirmed by the results of completed laboratory tests.
Źródło:
Inżynieria Rolnicza; 2008, R. 12, nr 5(103), 5(103); 299-306
1429-7264
Pojawia się w:
Inżynieria Rolnicza
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical and experimental study on seakeeping performance of a high-speed trimaran with T-foil in head waves
Autorzy:
Li, Ang
Li, Yunbo
Powiązania:
https://bibliotekanauki.pl/articles/258842.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
trimaran
T-foil
URANS
longitudinal motion
model test
Opis:
The longitudinal motion characteristics of a slender trimaran equipped with and without a T-foil near the bow are investigated by experimental and numerical methods. Computational fluid dynamics ( CFD) method is used in this study. The seakeeping characteristics such as heave, pitch and vertical acceleration in head regular waves are analyzed in various wave conditions. Numerical simulations have been validated by comparisons with experimental tests. The influence of large wave amplitudes and size of T-foil on the longitudinal motion of trimaran are analyzed. The present systematic study demonstrates that the numerical results are in a reasonable agreement with the experimental data. The research implied that the longitudinal motion response values are greatly reduced with the use of T-foil.
Źródło:
Polish Maritime Research; 2019, 3; 65-77
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Visual Detection Method of Longitudinal Crack Based on Computer Image Processing During Slab Continuous Casting
Autorzy:
Liu, Y.
Wang, X.
Sun, Y.
Du, F.
Gao, Y.
Wang, F.
Wang, J.
Powiązania:
https://bibliotekanauki.pl/articles/351636.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
longitudinal crack
visual detection
image processing
continuous casting
Opis:
Based on the mould temperature measured by thermocouples during slab continuous casting, a difference of temperature thermograph is developed to detect slab cracks. In order to detect abnormal temperature region caused by longitudinal crack, the suspicious regions are extracted and divided by virtue of computer image processing algorithms, such as threshold segmentation, connected region judgement and boundary tracing. The abnormal regions are then determined and labeled with the eight connected component labeling algorithm. The boundary of abnormal region is also extracted to depict characteristics of longitudinal crack. Based on above researches, longitudinal crack with abnormal temperature region can be detected and is different from other abnormalities. Four samples of temperature drop are picked up to compare with longitudinal crack on the abnormal region formation, length, width, shape, et al. The results show that the abnormal region caused by longitudinal crack has a linear and vertical shape. The height of abnormal region is more than the width obviously. The ratio of height to width is usually larger than that of other temperature drop regions. This method provides a visual and easy way to detect longitudinal crack and other abnormities. Meanwhile it has a positive meaning to the intelligent and visual mould monitoring system of continuous casting.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 2; 673-680
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł

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