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Wyświetlanie 1-7 z 7
Tytuł:
Wykorzystanie analiz typu GIS do detekcji wybranych części anatomicznych ciała ludzkiego dla potrzeb badania wad postawy
The application of GIS analysis for the detection of selected anatomical parts of human body for the posture defects examination
Autorzy:
Tokarczyk, R.
Tokarczyk, P.
Powiązania:
https://bibliotekanauki.pl/articles/130201.pdf
Data publikacji:
2009
Wydawca:
Stowarzyszenie Geodetów Polskich
Tematy:
wady postawy
fotogrametria cyfrowa bliskiego zasięgu
krzywizna powierzchni
analiza GIS
posture defect
close-range photogrammetry
surface curvature
GIS analyses
Opis:
Parametry określające wady postawy są obliczane na podstawie przestrzennego położenia wybranych punktów anatomicznych ciała człowieka, którymi są elementy układu kostnego, przeniesione na powierzchnię ciała metodą palpacji. Zatem charakter punktów pomiarowych pogarsza dokładność wyznaczenia parametrów oceny postawy. Tymczasem współczesne metody pomiarowe, w tym fotogrametryczne pozwalają na uzyskanie dokładności pomiaru znacznie przewyższające dokładność sygnalizacji punktów pomiarowych. Metoda badawcza opisana w niniejszym opracowaniu bazuje na założeniu, że kształt powierzchni ciała odzwierciedla położenie elementów kostnych, kluczowych dla badania wad postawy, zatem przez analizy tej powierzchni można znaleźć potrzebne punkty pomiarowe. Model powierzchni ciała człowieka o dokładności wyznaczenia jego punktów poniżej 1 mm uzyskano wykorzystując fotogrametryczny system bliskiego zasięgu PI3000 Topcon do opracowania pary zbieżnych zdjęć wykonanych cyfrowymi aparatami fotograficznymi. Poddano go analizom, wykorzystując programy: GeoMedia Professional z nakładką Grid oraz Idrisi-Andes. Przebieg kręgosłupa uzyskano drogą analiz DEM służących do detekcji spływu wody, zakładając zjawisko podobieństwa powierzchni pleców w rejonie kręgosłupa do doliny rzecznej. W pomiarach służących ocenie wad postawy wykorzystuje się wybrane punkty anatomiczne jako definiujące układ antropometryczny, są to najczęściej: wyrostek kolczysty siódmego kręgu szyjnego C7 (vertebra prominens) oraz kolce biodrowe tylne górne (spina iliaca posterior superior). Próby ich detekcji dokonano wstępnie za pomocą wyznaczenia linii kręgosłupa w GeoMedia, a potem przez wykorzystanie krzywizny powierzchni z użyciem Idrisi-Andes. W drugiej fazie detekcji okazało się, że wymaga ona wygładzenia modelu powierzchni i jest to niezbędny warunek jej poprawnej klasyfikacji dotyczącej form wysokościowych.
Parameters defining posture defects are computed based on the spatial location of selected anatomical points of the human body, which include the elements of the osseous system transferred on the body surface using the palpation method. Thus, the very nature of measured points deteriorates the accuracy of posture rating parameters. Meanwhile, present measurement methods, including photogrammetric ones, allow obtaining the measurement accuracy highly exceeding that of measurement points marking. The research method described in this paper is based on an assumption that the shape of the body surface reflects the position of the osseous elements, which are significant for the posture disorder analysis. Therefore, one can find the necessary points by analysing the said surface. The model of the human body surface was acquired using PI3000close-range photogrammetry system by Topcon, with the accuracy of measured points of 1mm. Images used as an input for the PI3000 system were acquired by two digital cameras as convergent pairs. Afterwards, the model was analysed using GeoMedia Professional with Grid extension and Idrisi Andes software. The trace of the spine was determined using DEM analysis used for water flow detection, assuming the comparability of back surface near the spine to the river valley. When determining the posture disorders, the anatomical points which are most often used for the determination of the anthropometrical coordinate system are as follows: the C7 spinous process and the posterior superior iliac spine. Attempts at detecting them were performed initially by determining the spine line (GeoMedia), then by using the surface curvature (Idrisi Andes). During the second phase of detection it turned out that it was necessary to smooth the surface model, and that it was an indispensable condition for the correct classification of height forms.
Źródło:
Archiwum Fotogrametrii, Kartografii i Teledetekcji; 2009, 19; 423-435
2083-2214
2391-9477
Pojawia się w:
Archiwum Fotogrametrii, Kartografii i Teledetekcji
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adsorption efficiency of selected natural and synthetic sorbents
Autorzy:
Pavolova, H.
Bakalar, T.
Puskarova, P.
Powiązania:
https://bibliotekanauki.pl/articles/184318.pdf
Data publikacji:
2016
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
porous surface
radius
curvature
Opis:
Sorbents are substances binding other substances on their surface. Effective sorbents have a porous surface. The adsorption activity of the surface is closely related to the local radius of curvature of surface irregularities. Suitable sorbents are natural and synthetic solids of amorphous or microcrystalline structure (Kyncl et al. 2008). Globally, the following adsorbents are the most used: activated carbon, zeolites, silica gel, activated alumina (Bakalár et al. 2005). A characteristic of effective adsorbents is large surface area of hundreds of square meters multiply by gram to the power of minus one [m 2 ∙g −1 ]. Other important features of adsorbents include specific volume, porosity, average pore diameter, pore distribution, etc. Some natural materials or industrial waste with high adsorption capacity, which naturally reduces the overall cost of their disposal, can be used for adsorption of heavy metal cations. Some of low-cost sorbents are: lignin, chitin, seaweed/ algae, zeolites, clays, fly-ash, peat, sand grains coated with iron oxide, modified cotton and wool (Pavolová et al 2006). In experiments of Cu and Zn removal from wastewater the following adsorbents were used (Bakalár et al. 2005): - Lewatit S100, which is strongly acidic, gel-like cationic ion exchange resin with particles of equal size based on styrene-divinylbenzene copolymers. Monodisperse beads are chemically and osmotically highly stable. - Chitosan, which is prepared from chitin, naturally occurring in the shells of crustaceans, by deacetylation using strongly alkaline solution. Chitin is a homopolymer composed of β-(1-4)- -N-acetyl-D-glucosamine. The ability of crustaceans shells to bind metal ions is assigned to the presence of exoskeleton in the molecule of chitin and chitosan. - Synthetic zeolite, which is included in the group of aluminosilicates, was prepared by zeolitization of fly-ash from energy industry. - Bentonite, which is included in the group of hydrated aluminosilicates, the main ingredient is mineral montmorillonite. - Slovakit, which is an inorganic composite sorbent made from pure natural ingredients. Its composition is a subject of patent protection. The aspect of time, i.e. the time the specific sorbent reaches the maximum adsorption capacity for the heavy metal removed, is also important in removal of Cu 2+, Zn 2+ and Pb 2+ cations. The experimental measurements of cations adsorption using the above mentioned sorbents are made at the initial concentration of 10 mg∙L −1 of heavy metal. The time to reach the equilibrium for all sorbent during separation of Cu 2+ cations from model solutions of wastewater was about 60 seconds except for chitosan for which it was almost 2 minutes. This is relatively very good result. The equilibrium of Zn 2+ cations adsorption at the experimental measurements for all the selected sorbents was reached in about 80 seconds except for chitosan for which this time was 2 minutes 5 seconds. This time was on average around 20 minutes longer compared to the adsorption of Cu 2+ ions. The adsorption of Pb 2+ cations was carried out at the experimental measurements in about 83 seconds for all the selected sorbents, except for synthetic zeolite for which the time was 1 min 15 seconds. The adsorption of Pb 2+ cations compared to the cations of Cu 2+ was 23 seconds faster and compared to the cations of Zn 2+ was 3 seconds longer. The most appropriate for the removal of Cu 2+, Zn 2+, and Pb 2+ is Lewatit S100 among the used sorbents; the equilibrium was reached in approximately 35 seconds, 45 seconds, and 83 seconds for Zn 2+, Cu 2+, and Pb 2+, respectively. According to the experimental measurements the longest adsorption time was for chitosan – about 2 minutes for Cu 2+ and Zn 2+, and about 1.5 minutes for Pb 2+.
Źródło:
Geology, Geophysics and Environment; 2016, 42, 1; 114-115
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The quick measure of a NURBS surface curvature for accurate triangular meshing
Autorzy:
Kniat, A.
Powiązania:
https://bibliotekanauki.pl/articles/258692.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
triangulation
meshing
curvature
NURBS surface
optimization
Opis:
NURBS surfaces are the most widely used surfaces for three-dimensional models in CAD/ CAE programs. When a model for FEM calculation is prepared with a CAD program it is inevitable to mesh it finally. There are many algorithms for meshing planar regions. Some of them may be used for meshing surfaces but it is necessary to take the curvature of the surface under consideration to avoid poor quality mesh. The mesh must be denser in the curved regions of the surface. In this paper, instead of analysing a surface curvature, the method to assess how close is a mesh triangle to the surface to which its vertices belong, is presented. The distance between a mesh triangle and a parallel tangent plane through a point on a surface is the measure of the triangle quality. Finding the surface point whose projection is located inside the mesh triangle and which is the tangency point to the plane parallel to this triangle is an optimization problem. Mathematical description of the problem and the algorithm to find its solution are also presented in the paper.
Źródło:
Polish Maritime Research; 2014, 2; 41-44
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applications of PDES inpainting to magnetic particle imaging and corneal topography
Autorzy:
Andrisani, Andrea
Mininni, Rosa Maria
Mazzia, Francesca
Settanni, Giuseppina
Iurino, Alessandro
Tangaro, Sabina
Tateo, Andrea
Bellotti, Roberto
Powiązania:
https://bibliotekanauki.pl/articles/255026.pdf
Data publikacji:
2019
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
PDEs inpainting
medical imaging
magnetic particle imaging
radial curvature image
anterior surface of a cornea
Opis:
In this work we propose a novel application ol Partial Differential Equations (PDEs) inpainting techniques to two medical contexts. The first one concerning recovering of concentration maps for superparamagnetic nanoparticles, used as tracers in the framework of Magnetic Particle Imaging. The analysis is carried out by two set of simulations, with and without adding a source of noise, to show that the inpainted images preserve the main properties of the original ones. The second medical application is related to recovering data of corneal elevation maps in ophthalmology. A new procedure consisting in applying the PDEs inpainting techniques to the radial curvature image is proposed. The images of the anterior corneal surface are properly recovered to obtain an approximation error of the required precision. We compare inpainting methods based on second, third and fourth-order PDEs with standard approximation and interpolation techniques.
Źródło:
Opuscula Mathematica; 2019, 39, 4; 453-482
1232-9274
2300-6919
Pojawia się w:
Opuscula Mathematica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multi-scale curvature tensor analysis of machined surfaces
Autorzy:
Bartkowiak, T.
Brown, C.
Powiązania:
https://bibliotekanauki.pl/articles/1203966.pdf
Data publikacji:
2016
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
curvature tensor
surface metrology
multi-scale geometric characterization
machining
tensor krzywizny
metrologia powierzchni
charakterystyka geometryczna
obróbka
Opis:
This paper demonstrates the use of multi-scale curvature analysis, an areal new surface characterization technique for better understanding topographies, for analyzing surfaces created by conventional machining and grinding. Curvature, like slope and area, changes with scale of observation, or calculation, on irregular surfaces, therefore it can be used for multi-scale geometric analysis. Curvatures on a surface should be indicative of topographically dependent behavior of a surface and curvatures are, in turn, influenced by the processing and use of the surface. Curvatures have not been well characterized previously. Curvature has been used for calculations in contact mechanics and for the evaluation of cutting edges. In the current work two parts were machined and then one of them was ground. The surface topographies were measured with a scanning laser confocal microscope. Plots of curvatures as a function of position and scale are presented, and the means and standard deviations of principal curvatures are plotted as a function of scale. Statistical analyses show the relations between curvature and these two manufacturing processes at multiple scales.
Źródło:
Archives of Mechanical Technology and Materials; 2016, 36; 44-50
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Study of Quantum Effects in General Relativity
Autorzy:
Sooriyaarachchi, V. K. C.
Wijewardena Gamalath, K. A. I. L.
Powiązania:
https://bibliotekanauki.pl/articles/1058092.pdf
Data publikacji:
2019
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Hawking effect
Rindler observer
Schwarzschild black hole
Unruh effects
event horizon
information loss paradox
scalar curvature
surface gravity
transplanckian problem
Opis:
The present work discusses the conceptual and technical issues encountered in formulating a quantized theory of gravity, via the reconciliation of quantum mechanics and general relativity. Quantum effects arising in a classically defined space-time derived through a semi classical approximation are studied at length and the significance of the particle interpretation in quantum field theory in the origin of such effects is established. The contradicting nature of the quantum effects against classically established principles is studied by considering the Hawking effect in a Schwarzschild black hole space-time. Further, the limits of prominent manifestation of the quantum effects with regards to the black hole mass is calculated taking into consideration the cosmic microwave background and the lifetime of the universe. Quantum effects are established as essential in incorporating thermal physics and black hole mechanics in a consistent formulation. Finally, the validity of the semi classical approximation is studied in terms of Planck scale black holes, transplanckian problem and the information loss paradox and the requirement for a fully quantized theory of gravity is realized.
Źródło:
World Scientific News; 2019, 134, 2; 198-219
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cortical pattern detection for the developing brain: a 3D vertex labeling and skeletonization approach
Autorzy:
Clouchoux, C.
Kudelski, D.
Bouyssi-Kobar, M.
Viseur, S.
du Plessis, A.
Evans, A.
Mari, J.-L.
Limperopoulos, C.
Powiązania:
https://bibliotekanauki.pl/articles/333059.pdf
Data publikacji:
2010
Wydawca:
Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:
rozwój mózgu
ocena krzywizny
wychwytywanie cech
sulcal pattern
brain development
in-vivo MRI
cortical surface
curvature estimation
morphological operators
feature extraction
Opis:
Normal brain development is associated with expansion and folding of the cerebral cortex in a normal sequence of gyral–sulcal formation. We propose a global approach for measuring the cortical folding pattern of the developing brain. Our method measures geometric features directly on the cortical surface mesh, based on vertex labeling and skeletonization. The resulting extraction provides an accurate representation of global cortical organization. We applied this method to 17 young infants in order to characterize the evolution of cortical organization in the developing brain.
Źródło:
Journal of Medical Informatics & Technologies; 2010, 16; 161-166
1642-6037
Pojawia się w:
Journal of Medical Informatics & Technologies
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-7 z 7

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