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Tytuł:
2D Electrical Resistivity Tomography interpretation ambiguity - example of field studies supported with analogue and numerical modelling
Autorzy:
Bania, G.
Ćwiklik, M.
Powiązania:
https://bibliotekanauki.pl/articles/184445.pdf
Data publikacji:
2013
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
electrical resistivity tomography ERT
ambiguity
2D inversion
analogue modelling
numerical modelling
Opis:
Single Electrical Resistivity Tomography (ERT) survey was carried out in the Manor and Park Complex in Nowa Huta (Krakow Branice, Poland). It was applied at a small distance and parallel to the longer wall of a monumental building containing an empty 3 m deep basement. Analogue modelling was performed in order to recreate the field study at the proper scale. The laboratory set-up consisted of a water tank where electrodes were mounted to the particular plate, which rested on water surface. The basement model was made out of a non-conducting material. The default and robust inversions were tested and these variants were also considered with the use of numerical modelling. Laboratory experiments have confirmed that zones visible in the interpreted field section are caused by the influence of the building cellar located next to the survey line. Zones of this kind are additionally disturbed by the local geological structure. The experiment has pointed out, among others, that as the distance between the survey line and the underground body increases, the inversion results are still burdened by an object influence. Thus, similar situations can be verified with the use of analogue modelling presented in this paper or 3D numerical one.
Źródło:
Geology, Geophysics and Environment; 2013, 39, 4; 331-339
2299-8004
2353-0790
Pojawia się w:
Geology, Geophysics and Environment
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
2D modelling of a sensor for electrical capacitance tomography in ECTsim toolbox
Dwuwymiarowe modelowanie sondy do elektrycznej tomografii pojemnościowej w pakiecie ECTsim
Autorzy:
Kryszyn, J.
Smolik, W.
Powiązania:
https://bibliotekanauki.pl/articles/408824.pdf
Data publikacji:
2017
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
electrical capacitance tomography
2D modelling
algebra of sets
tomografia elektryczna pojemnościowa
modelowanie dwuwymiarowe
algebra zbiorów
Opis:
Electrical capacitance tomography is used to visualize a spatial distribution of dielectrical permittivity of materials placed in a tomographic sensor. An image is reconstructed from measurements of mutual capacitances of electrodes placed around the examined volume. This technique is characterized by very high temporal resolution – it is possible to achieve even few thousands of images per second. One of drawbacks of the method is low spatial resolution. Electrical capacitance tomography is mainly used in industry, e.g. for multiphase flow visualization. One of important elements of a tomographic system is a sensor which parameters influence quality of measurements and therefore affects quality of reconstructed images. In the Division of Nuclear and Medical Electronics a Matlab toolbox called ECTsim was developed. It is used for modelling of sensors, simulations of electrical field and image reconstruction. In this article we present the latest improvement which is modelling of a sensor using algebra of sets. Using primitive elements like rectangle and sector of a ring it is possible to perform operations like union, intersection and difference of two elements with a designed language. With such tools it is easy to prepare complex models of tomographic sensors which have different geometries. In this paper we show two models of sensors with different geometry in order to show how ECTsim solves forward problem.
Elektryczna tomografia pojemnościowa służy do obrazowania rozkładu przenikalności elektrycznej materiałów w sondzie. Obraz rekonstruowany jest dzięki pomiarom pojemności wzajemnych elektrod umieszczonych wokół badanego obszaru. Ta technika obrazowa charakteryzuje się dużą rozdzielczością czasową – możliwe jest obrazowanie nawet kilku tysięcy przekrojów na minutę. Wadą jest niska przestrzenna zdolność rozdzielcza. Elektryczną tomografię pojemnościową stosuje się w przemyśle, między innymi do obrazowania przepływów wielofazowych. Istotnym elementem systemu tomograficznego jest sonda, której parametry wpływają na jakość pomiaru, a tym samym na jakość rekonstruowanego obrazu. W Zakładzie Elektroniki Jądrowej i Medycznej stworzono pakiet ECTsim uruchamiany w środowisku Matlab, który służy do modelowania sond tomograficznych, symulacji pola elektrycznego oraz rekonstrukcji obrazów. W niniejszym artykule opisano najnowszą modyfikację pakietu polegającą na modelowaniu sondy przy pomocy algebry zbiorów. Wprowadzono podstawowe kształty geometryczne, takie jak prostokąt i wycinek pierścienia, oraz zaproponowano język opisujący operacje sumowania, odejmowania i iloczynu elementów, co pozwala na proste tworzenie złożonych modeli sond tomograficznych o różnych geometriach. W artykule pokazujemy modele dwóch różnych sond tomograficznych i prezentujemy, jak ECTsim rozwiązuje problem prosty.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2017, 7, 1; 146-149
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A 56-year-old man with RT-PCR negative nasopharyngeal swabs with Coronavirus Disease 2019 (COVID-19) Pneumonia
Autorzy:
Dworzańska, A.
Tudrujek-Zdunek, M.
Mosiewicz, J.
Panasiuk, L.
Tomasiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/2085530.pdf
Data publikacji:
2020
Wydawca:
Instytut Medycyny Wsi
Tematy:
RT-PCR
pneumonia
Covid-19
Coronavirus Disease 2019
chest computed tomography
real-time-reverse transcription-polymerase chain-reaction
Opis:
Introduction. Diagnostic procedure in Coronavirus Disease 2019 (COVID-19) is based mainly on performing real-time-reverse transcription-polymerase chain-reaction (RT-PCR), which has been accepted as the gold standard method. In some cases, such as mutations of the SARS-CoV-2 genome, variable viral load kinetics or laboratory errors, it can be false-negative. Case report. The case is presented of a 56-year-old man with respiratory tract symptoms, with twice negative results of real-time-reverse transcription-polymerase chain-reaction of nasopharyngeal swabs and positive chest computed tomography, with typical findings for COVID-19 pneumonia. Conclusions. Patients with negative RT-PCR results, but with positive computed tomography findings characteristic for COVID-19, should be treated as well as those infected.
Źródło:
Annals of Agricultural and Environmental Medicine; 2020, 27, 2; 317-318
1232-1966
Pojawia się w:
Annals of Agricultural and Environmental Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Biometrological Procedure Preceeding the Resurfacing
Autorzy:
Ryniewicz, A. M.
Madej, T.
Ryniewicz, A.
Bojko, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/221556.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cox-arthrosis
resurfacing
modelling
bio-metrology
computed tomography
Opis:
This paper presents a preoperative hip reconstruction method with diagnosed osteoarthritis using Durom Hip Resurfacing System (DHRS). The method is based on selection and application of the resurfacing to the pelvis reconstructed on the basis of computed tomography. Quality and geometrical parameters of distinguished tissues have a fundamental significance for locating and positioning the acetabular and femoral components. The application precedes the measurements of anatomical structures on a complex numerical model. The developed procedure enables functional selection of endo-prosthesis and its positioning in such a way that it secures geometric parameters within the bone bed and the depth , inclination angles and ante-version of the acetabular component, the neck-shaft angle and ante-torsion angle of the neck of the femoral bone, and reconstruction of the biomechanical axis of the limb and the physiological point of rotation in the implanted joint. Proper biomechanics of the bone-joint complex of the lower limb is determined by correlation of anatomical-geometrical parameters of the acetabular component and parameters of the femoral bone.
Źródło:
Metrology and Measurement Systems; 2016, 23, 1; 97-106
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Structural Analysis of Four Radiosonde Models
Porównawcza analiza strukturalna czterech modeli radiosond
Autorzy:
Hegyi, Norbert
Jósvai, János
Powiązania:
https://bibliotekanauki.pl/articles/36450313.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
radiosonde
unmanned free balloon
computed tomography measurement
collision test
radiosonda
balon wolny bezzałogowy
tomografia komputerowa
test zderzeniowy
Opis:
In this study, we first performed a comprehensive structural analysis of four models of radiosondes (devices intended for use as the meteorological probe of a sounding balloon) manufactured by three different companies - Graw, Vaisala and Meteomodem. The radiosondes were disassembled for visual inspection and manual measurement, three-dimensional computed tomography images were taken of their inner structure, and the outer shapes of the radiosondes were scanned with a structured-light three-dimensional scanner. The structural properties of the radiosondes thus identified were then compared to one other, based on which the Meteomodem M10 was ranked as the least harmful in a potential collision. Next, the Meteomodem M10 radiosonde was used in collision tests with a heavy target and with a pumpkin model, in order to evaluate the possible damage caused by and to the radiosonde in different types of collisions.
W pracy przeprowadzono kompleksową analizę strukturalną czterech modeli radiosond (urządzeń stosowanych przy balonach meteorologicznych) produkowanych przez trzy różne firmy: Graw, Vaisala i Meteomodem. Radiosondy rozłożono na części w celu dokonania oględzin i pomiarów ręcznych, wykonano trójwymiarowe zdjęcia tomograficzne ich wewnętrznej struktury oraz zeskanowano ich zewnętrzne kształty za pomocą trójwymiarowego skanera. Po porównaniu właściwości strukturalnych radiosond, model Meteomodem M10 został uznany za najmniej szkodliwy w potencjalnym zderzeniu z przeszkodą. Następnie przeprowadzono testy zderzeniowe radiosondy Meteomodem M10 z przeszkodą twardą oraz miękką w celu oceny możliwych uszkodzeń w różnych typach kolizji.
Źródło:
Transactions on Aerospace Research; 2021, 4 (265); 68-81
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A giant boring in a Silurian stromatoporoid analysed by computer tomography
Autorzy:
Beuck, L
Wisshak, M.
Munnecke, A.
Freiwald, A.
Powiązania:
https://bibliotekanauki.pl/articles/20045.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Upper Visby Formation
computer tomography
Sweden
Densastroma pexisum
paleontology
Gotland Island
Silurian
stromatoporoid
trace fossil
Osprioneides kampto
analysis
Opis:
This study describes the largest known Palaeozoic boring trace, Osprioneides kampto igen. et isp. nov., found within a stromatoporoid Densastroma pexisum from the Upper Visby Formation (lower Wenlock, Silurian) on the island of Gotland, Sweden. Differences between the physical properties of the stromatoporoid and the dense micritic infilling of the borings allowed the application of the CT−scan technology for the 2D and 3D−visualisation of this rare trace. The additional application of a stereoscopic technique on these CT images and movies enhances its value for unravelling spatial orientations. This non−destructive method has a great potential for future macroas well as microboring analyses. The trace maker, most likely a worm, infested the hosting colony post−mortem with up to 120 mm long borings measuring 5–17 mm in diameter. Smaller forms of Trypanites and Palaeosabella within the same stromatoporoid preferentially occur in the outer coenosteum and occasionally in abandoned borings of O. kampto. The stratigraphic position of O. kampto follows the “Great Ordovician Biodiversification Event” in time, and reflects the increase in diversity of boring species. Borings with penetration depths of 120 mm are, however, unique findings for the Palaeozoic and were not exceeded until some 260 million years later (Bajocian, Middle Jurassic) when the “Mesozoic Marine Revolution” led to convergent reinventions as a result of enhanced predation, grazing pressure, and ecospace competition.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of precise pulse onset determination using the Akaike Information Criterion for Ultrasound Transmission Tomography
Autorzy:
Pruchnicki, Piotr
Opieliński, Krzysztof J.
Powiązania:
https://bibliotekanauki.pl/articles/2146650.pdf
Data publikacji:
2021
Wydawca:
Politechnika Poznańska. Instytut Mechaniki Stosowanej
Tematy:
Akaike Information Criterion
AIC
pulse wave
transmission method
ultrasound tomography
kryterium informacyjne Akaike
fala tętna
metoda transmisyjna
tomografia ultradźwiękowa
Opis:
Information criteria used in statistics for model selection can be used to accurately determine pulse transition times in transmission methods. The most popular information criteria are the Akaike Information Criterion (AIC) and the Bayesian Schwartz Criterion (BIC). These criteria are considered the most reliable tests of model type and structure and are computationally simple. In this paper, an algorithm developed according to the AIC criterion is used to determine the transition time from transmission tomography measurements acquired with a multi-element ultrasonic ring array, which is the scanning element of the novel prototype of ultrasound tomography device for detecting and estimating the malignancy of female breast cancer in vivo. As a result, a new algorithm was developed to precise search for the onset of the recorded receiving pulse. The algorithm was tested in an aqueous environment using elementary pairs of transmitting and receiving ultrasonic transducers of a tomographic ring array.
Źródło:
Vibrations in Physical Systems; 2021, 32, 1; art. no. 2021115
0860-6897
Pojawia się w:
Vibrations in Physical Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new concept of discretisation model for imaging improving in ultrasound transmission tomography
Nowa koncepcja dyskretyzacji modelu celem podniesienia jakości obrazowania w transmisyjnej tomografii ultradźwiękowej
Autorzy:
Rymarczyk, Tomasz
Polakowski, Krzysztof
Sikora, Jan
Powiązania:
https://bibliotekanauki.pl/articles/408251.pdf
Data publikacji:
2019
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
Ultrasound Transmission Tomography
image reconstruction
constrained optimisation
circular pixel
spherical voxel
Transmisyjna Tomografia Ultradźwiękowa
obrazowanie
optymalizacja z ograniczeniami
piksel kołowy
wokse kulisty
Opis:
In this paper a new version of discretisation model for Ultrasonic Transmission Tomography is presented. The algorithm has been extensively tested for synthetic noisy data on various configurations of internal objects. In order to improve the imaging quality, the pixels/voxels have been enlarged compared to the figures inscribed in pixels/voxels however no more than figures described on the standard square pixels or cubic voxels. The proposed algorithm provides better quality of imaging.
W tym artykule zaproponowano nową wersję dyskretyzacji modelu dla Ultradźwiękowej Tomografii Transmisyjnej. Przedstawiony algorytm był wszechstronnie przetestowany dla danych syntetycznych zaszumionych dla różnych konfiguracji obiektów wewnętrznych. W celu poprawienia jakości obrazowania, piksele/woksele zostały powiększone w stosunku do figur wpisanych w piksele/woksele, jednak nie więcej niż figury opisane na standardowych kwadratowych pikselach lub sześciennych wokselach. Proponowany algorytm zapewnia lepszą jakość obrazowania.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2019, 9, 4; 48-51
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new imaging algorithm for electric capacitance tomography
Nowy algorytm obrazowania w elektrycznej tomografii pojemnościowej
Autorzy:
Pańczyk, M.
Sikora, J.
Powiązania:
https://bibliotekanauki.pl/articles/158998.pdf
Data publikacji:
2016
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Elektrotechniki
Tematy:
electric capacitance tomography
partial differential equations
adjoint equation
inverse problem
elektryczna tomografia pojemnościowa
równania różniczkowe cząstkowe
równanie sprzężone
zagadnienie odwrotne
Opis:
A new imaging algorithm of permittivity for Electrical Capacitance Tomography (ECT) was proposed in this paper. Some aspects of sensitivity analysis and the application of adjoint variables were discussed. In the final section of this paper some advantages and disadvantages were shown.
W pracy przedstawiono „nowy” algorytm obrazowania przenikalności elektrycznej w Elektrycznej Tomografii Pojemnościowej. Omówiono aspekty związane z analizą wrażliwościową i zmienna sprzężoną. Przedstawiono jej interpretację fizyczną. Wskazano na zalety i wady zaproponowanej metody obrazowania.
Źródło:
Prace Instytutu Elektrotechniki; 2016, 274; 27-41
0032-6216
Pojawia się w:
Prace Instytutu Elektrotechniki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new statistical reconstruction method for the computed tomography using an X-ray tube with flying focal spot
Autorzy:
Cierniak, Robert
Pluta, Piotr
Waligóra, Marek
Szymański, Zdzisław
Grzanek, Konrad
Pałka, Filip
Piuri, Vincenzo
Powiązania:
https://bibliotekanauki.pl/articles/2031110.pdf
Data publikacji:
2021
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
computed tomography
iterative statistical reconstruction method
flying focal spot
Opis:
This paper presents a new image reconstruction method for spiral cone- beam tomography scanners in which an X-ray tube with a flying focal spot is used. The method is based on principles related to the statistical model-based iterative reconstruction (MBIR) methodology. The proposed approach is a continuous-to-continuous data model approach, and the forward model is formulated as a shift-invariant system. This allows for avoiding a nutating reconstruction-based approach, e.g. the advanced single slice rebinning methodology (ASSR) that is usually applied in computed tomography (CT) scanners with X-ray tubes with a flying focal spot. In turn, the proposed approach allows for significantly accelerating the reconstruction processing and, generally, for greatly simplifying the entire reconstruction procedure. Additionally, it improves the quality of the reconstructed images in comparison to the traditional algorithms, as confirmed by extensive simulations. It is worth noting that the main purpose of introducing statistical reconstruction methods to medical CT scanners is the reduction of the impact of measurement noise on the quality of tomography images and, consequently, the dose reduction of X-ray radiation absorbed by a patient. A series of computer simulations followed by doctor’s assessments have been performed, which indicate how great a reduction of the absorbed dose can be achieved using the reconstruction approach presented here.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2021, 11, 4; 271--286
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new subdisarticulated machaeridian from the Middle Devonian of China: Insights into taphonomy and taxonomy using X-ray microtomography and 3D-analysis
Autorzy:
GÜGEL, BENJAMIN
DE BAETS, KENNETH
JERJEN, IWAN
SCHUETZ, PHILIPP
KLUG, CHRISTIAN
Powiązania:
https://bibliotekanauki.pl/articles/945234.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
annelida
lepidocoleidae
tomography
spiers
taphonomy
devonian
china
guangx
Opis:
Machaeridians are an extinct group of armoured annelids, which are mainly known from isolated sclerites present from the Ordovician to the Permian. Based on articulated specimens with preserved soft-tissues and trace fossils, derived machaeridians are interpreted to have an infaunal burrowing mode of life. However, the taphonomy of sclerite associations is still largely unstudied. We herein investigated associated sclerites from the Middle Devonian of China using micro-computer tomography and 3D-analysis. These sclerites belong to a single individual and lie in close proximity. The absence of indications for current alignment, major bioturbation or other processes causing a disarticulation as reflected in the randomly arranged dacryoconarids suggest that the sclerites became disarticulated in the course of the normal decay processes, perhaps aided by scavenging and incomplete burial. The unique morphology of the sclerites indicates that the specimen presented here belongs to a previously undescribed species, which we describe herein as Lepidocoleus kuangguoduni sp. nov.
Źródło:
Acta Palaeontologica Polonica; 2017, 62, 2; 237-247
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new Triassic-Jurassic section in the southern part of the Holy Cross Mts. (Poland) implications for palaeogeography
Autorzy:
Kozłowska, M.
Barski, M.
Mieszkowski, R.
Antoszewska, A.
Powiązania:
https://bibliotekanauki.pl/articles/2059877.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
sedimentology
fluvial deposits
shallow marine deposits
Middle Jurassic transgression
dinoflagellate cysts
stratigraphy
electrical resistivity tomography
ERT
Opis:
Sedimentological, stratigraphical and geophysical studies across a new Triassic-Jurassic transition section in the Holy Cross Mts., Poland have revealed a large sedimentary hiatus embracing the entire latest Triassic–Early Jurassic – earliest Middle Jurassic time interval and yielded new data on the Triassic fluvial system and on Middle Jurassic shallow marine sedimentation. The presence of organic-walled dinoflagellate cysts allowed a precise age assignment of the black clay facies. Regional discussions and comparisons may be made with other areas with a similar depositional environment in Poland. For the first time a counterpart of the “Kościeliskie Beds” lithostratigraphic unit is proposed to exist in the Holy Cross Mts. area.
Źródło:
Geological Quarterly; 2016, 60, 2; 365--484
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A practical statistical approach to the reconstruction problem using a single slice rebinning method
Autorzy:
Cierniak, Robert
Pluta, Piotr
Kaźmierczak, Andrzej
Powiązania:
https://bibliotekanauki.pl/articles/1837534.pdf
Data publikacji:
2020
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
reconstruction algorithm
statistical iterative method
computed tomography
Opis:
The paper presented here describes a new practical approach to the reconstruction problem applied to 3D spiral x-ray tomography. The concept we propose is based on a continuous-to-continuous data model, and the reconstruction problem is formulated as a shift invariant system. This original reconstruction method is formulated taking into consideration the statistical properties of signals obtained by the 3D geometry of a CT scanner. It belongs to the class of nutating reconstruction methods and is based on the advanced single slice rebinning (ASSR) methodology. The concept shown here significantly improves the quality of the images obtained after reconstruction and decreases the complexity of the reconstruction problem in comparison with other approaches. Computer simulations have been performed, which prove that the reconstruction algorithm described here does indeed significantly outperforms conventional analytical methods in the quality of the images obtained.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2020, 10, 2; 137-149
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A regularized Newton method in electrical impedance tomography using shape Hessian information
Autorzy:
Eppler, K.
Harbrecht, H.
Powiązania:
https://bibliotekanauki.pl/articles/970140.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
tomografia impedancyjna
optymalizacja kształtu
brzegowe równanie całkowe
electrical impedance tomography
shape optimization
boundary integral equation
Newton type descent
Opis:
The present paper is concerned with the identification of an obstacle or void of different conductivity included in a two-dimensional domain by measurements of voltage and currents at the boundary. We employ a reformulation of the given identification problem as a shape optimization problem as proposed by Roche and Sokolowski (1996). It turns out that the shape Hessian degenerates at the given hole which gives a further hint on the ill-posedness of the problem. For numerical methods, we propose a preprocessing for detecting the barycentre and a crude approximation of the void or hole. Then, we resolve the shape of the hole by a regularized Newton method.
Źródło:
Control and Cybernetics; 2005, 34, 1; 203-225
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Robust CNN Model for Diagnosis of COVID-19 Based on CT Scan Images and DL Techniques
Autorzy:
Eldeeb, Ahmed H.
Amr, Mohammed Nagah
Ibrahim, Amin S.
Kamel, Hesham
Fouad, Sara
Powiązania:
https://bibliotekanauki.pl/articles/2200729.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Deep learning
COVID-19
Artificial Intelligence
computed tomography
Convolutional Neural Networks
Opis:
The 2019 Coronavirus (COVID-19) virus has caused damage on people's respiratory systems over the world. Computed Tomography (CT) is a faster complement for RT-PCR during peak virus spread times. Nowadays, Deep Learning (DL) with CT provides more robust and reliable methods for classifying patterns in medical pictures. In this paper, we proposed a simple low training proposed customized Convolutional Neural Networks (CNN) customized model based on CNN architecture that layers which are optionals may be included such as the layer of batch normalization to reduce time taken for training and a layer with a dropout to deal with overfitting. We employed a huge dataset of chest CT slices images from diverse sources COVIDx-CT, which consists of a 16,146-image dataset with 810 patients of various nationalities. The proposed customized model's classification results compared to the VGG-16, Alex Net, and ResNet50 Deep Learning models. The proposed CNN model shows robustness by achieving an overall accuracy of 93% compared to 88%, 89%, and 95% for the VGG-16, Alex Net, and ResNet50 DL models for the classification of 3 classes. When this relates to binary classification, the classification accuracy of the proposed model and the VGG-16 models were identical (almost 100% accurate), with 0.17% of misclassification in the class of Non-Covid-19, the Alex Net model achieved almost 100% classification accuracy with 0.33% misclassification in the class of Non-Covid-19. Finally, ResNet50 achieved 95% classification accuracy with 5% misclassification in the Non-Covid-19 class.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 4; 731--739
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 501

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