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Wyszukujesz frazę "active detection" wg kryterium: Temat


Tytuł:
Monitoring of contamination of coal processing plants and environmental waters using bubble velocity measurements – advantages and limitations
Autorzy:
Zawala, J.
Malysa, E.
Krzan, M.
Malysa, K.
Powiązania:
https://bibliotekanauki.pl/articles/110915.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
bubble velocity
water purity
surface active contaminants
method detection
adsorption layer
Opis:
The paper presents fundamentals of a simple physicochemical method (SPMD) and analysis of results obtained when the method was applied for detection of organic contaminations (surface-active substances SAS) in samples of environmental and industrial waters. The method is based on measurements of variations of air bubble local velocities, which can be significantly changed in presence of surface-active contaminants. Lowering of the bubble velocity is a consequence of a motion induced dynamic adsorption layer (DAL) formed over surface of the rising bubble. The DAL formation retards the surface fluidity and the bubble rising velocity can be lowered by over 50% when the bubble surface is completely immobilized. We showed that the SPMD is a very sensitive tool (detection limit even below 1 ppm) for detection of various kinds of surface-active substances (ionic, non-ionic) in water samples. On the basis of results obtained using precise laboratory set-up, an accuracy of the SPMD is discussed. Moreover, effect of inert electrolyte addition on the bubble velocity lowering and value of detection limit of the SPMD is discussed. Simple approach, enabling quantitative analysis of the surface-active contaminants in samples collected, based on “equivalent concentrations” determination, is proposed. Results obtained for industrial (Jankowice and Knurow coal processing plants, Jaslo Refinery channel) and environmental waters (Wisloka and Ropa river) are used for detailed analysis and critical discussion of advantages and limitations of the SPMD.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 143-157
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on islanding detection of solar distributed generation based on best wavelet packet and neural network
Autorzy:
Xi, Zhongmei
Zhao, Faqi
Zhao, Xiangyang
Peng, Hong
Xi, Chuanxin
Powiązania:
https://bibliotekanauki.pl/articles/141157.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active distribution network
islanding detection
neural network
solar distributed generation
wavelet pocket transform
Opis:
The active distribution network (ADN) represents the future development of distribution networks, whether the islanding phenomenon occurs or not determines the control strategy adopted by the ADN. The best wavelet packet has a better time-frequency characteristic than traditional wavelet analysis in the different signal processing, because it can extract better and more information from the signal effectively. Based on wavelet packet energy and the neural network, the islanding phenomenon of the ADN can be detected. Firstly, the wavelet packet is used to decompose current and voltage signals of the public coupling point between the distributed photovoltaic (PV) system and power grid, and calculate the energy value of each decomposed frequency band. Secondly, the network is trained using the constructed energy characteristic matrix as a neural network learning sample. At last, in order to achieve the function of identification for islanding detection, lots of samples are trained in the neural network. Based on the actual circumstance of PV operation in the ADN, the MATLAB/SIMULINK simulation model of the ADN is established. After the simulation, there are good output results, which show that the method has the characteristics of high identification accuracy and strong generalization ability.
Źródło:
Archives of Electrical Engineering; 2019, 68, 4; 703-717
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zastosowanie aktywnej termografii podczerwonej z wymuszeniem mikrofalowym do wykrywania min lądowych typu PMN, PMN-2 oraz PMF-1
PMN, PMN-2 and PMF-1 Landmines Detection Using Active Infrared Thermography with Microwave Excitation
Autorzy:
Szymanik, B.
Powiązania:
https://bibliotekanauki.pl/articles/403504.pdf
Data publikacji:
2011
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
aktywna termografia podczerwona
grzanie mikrofalowe
wykrywanie min lądowych
active infrared thermography
microwave heating
landmines detection
Opis:
W pracy przedstawiono wyniki zastosowania aktywnej termografii podczerwonej z wymuszeniem mikrofalowym do wykrywania zakopanych w piasku ćwiczebnych min przeciwpiechotnych: PMN, PMN-2 oraz PMF-1. Wspomniane miny mają obudowy wykonane z tworzyw sztucznych oraz odznaczają się niską zawartością metalu, przez co są trudno wykrywalne standardowymi wykrywaczami metalu. Prezentowana nowa metoda wykrywania min lądowych wykorzystuje źródło mikrofal o dużej mocy do podgrzania gruntu wraz z zakopaną w nim miną. Wytworzona różnica temperatur jest obserwowana na powierzchni gruntu za pomocą czułej kamery termowizyjnej.
In this paper, active infrared thermography is used to detect antipersonnel landmines: PMN, PMN-2 and PMF-1. Mentioned landmines have very low metal content and their casings are made of plastic, therefore are considered as hard to detect using metal detectors. Presented new method of landmines detection, uses high power microwave source to heat the ground with buried landmine. Obtained temperature difference can be observed on the ground surface with sensitive thermovision camera.
Źródło:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2011, 2, 3 (5); 54-63
2081-5891
Pojawia się w:
Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Test Signal Design for Failure Detection: a Linear Programming Approach
Autorzy:
Scola, H. R.
Nikoukhah, R.
Delebecque, F.
Powiązania:
https://bibliotekanauki.pl/articles/908093.pdf
Data publikacji:
2003
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
automatyka
failure detection
large scale programming
failure isolation
bounded perturbations
active detection
Opis:
A new methodology for the design of filters that permits failure detection and isolation of dynamic systems is presented. Assuming that the normal and the faulty behavior of a process can be modeled by two linear systems subject to inequality bounded perturbations, a method for the on-line implementation of a test signal, guaranteeing failure detection, is proposed. To improve the fault detectability of the dynamic process, appropriate test signals are injected into the system. All the computations required by the proposed method are implemented as the solution of large sparse linear optimization problems. A simple numerical example is given to illustrate the proposed procedure.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2003, 13, 4; 515-526
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Porównanie wybranych metod wyznaczania obszaru płomienia w wizyjnym systemie diagnostycznym
Comparision of selected flame area detection methods in vision disgnostic system
Autorzy:
Sawicki, D.
Kotyra, A.
Powiązania:
https://bibliotekanauki.pl/articles/408672.pdf
Data publikacji:
2013
Wydawca:
Politechnika Lubelska. Wydawnictwo Politechniki Lubelskiej
Tematy:
wykrywanie brzegu obszaru
płomień
spalanie
kontur aktywny
edge detection
flame
combustion
active contour
Opis:
W pracy przedstawiono porównanie wybranych metod wykrywania krawędzi dla obrazów spalania pyłu węglowego. Porównano metodę gradientową Canny’ego z metodą zbiorów poziomicowych oraz metodą opartą o model konturu aktywnego Chan-Vese. Wyniki badań pokazują, że metoda korzystająca z modelu Chan-Vese dobrze odwzorowała brzeg obszaru.
This paper presents comparison edge detection method of combustion pulverized coal. Compared method are: Canny edge detection operator, level set method and Chan-Vese active contour method. Experimental results show that edges extracted with method based on Chan-Vese active contour model gives good result.
Źródło:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska; 2013, 4; 14-17
2083-0157
2391-6761
Pojawia się w:
Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of material defects in reinforced concrete slab using active thermography
Autorzy:
Różański, L.
Ziopaja, K.
Powiązania:
https://bibliotekanauki.pl/articles/114442.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
active IR (pulsed or step heating) thermography
damage detection
non-destructive testing
Opis:
In order to validate the practical usage of passive and active infrared thermography for bridge inspection, a number of experimental studies have been conducted. Concrete slab of dimension of 60×60×10 cm made of concrete of strength class C35/45 was the object of research. Steel bars type B500SP with a diameter of ø10 and ø12 mm were used as reinforcement of analyzed slab. Four structure discontinuities imitating damages were implemented inside the slab. Using various methods of thermal excitation, the sensitivity of the slab response using infrared cameras was investigated. The paper presents the results of experiment and FEM simulation.
Źródło:
Measurement Automation Monitoring; 2017, 63, 3; 82-85
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
On infinite horizon active fault diagnosis for a class of non-linear non-Gaussian systems
Autorzy:
Punčochář, I.
Šimandl, M.
Powiązania:
https://bibliotekanauki.pl/articles/330710.pdf
Data publikacji:
2014
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
active fault detection
nonlinear stochastic system
optimal input design
dynamic programming
detekcja błędu
układ stochastyczny
układ nieliniowy
optymalizacja pobudzenia
programowanie dynamiczne
Opis:
The paper considers the problem of active fault diagnosis for discrete-time stochastic systems over an infinite time horizon. It is assumed that the switching between a fault-free and finitely many faulty conditions can be modelled by a finite-state Markov chain and the continuous dynamics of the observed system can be described for the fault-free and each faulty condition by non-linear non-Gaussian models with a fully observed continuous state. The design of an optimal active fault detector that generates decisions and inputs improving the quality of detection is formulated as a dynamic optimization problem. As the optimal solution obtained by dynamic programming requires solving the Bellman functional equation, approximate techniques are employed to obtain a suboptimal active fault detector.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2014, 24, 4; 795-807
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Active fault diagnosis based on stochastic tests
Autorzy:
Poulsen, N. K.
Niemann, H.
Powiązania:
https://bibliotekanauki.pl/articles/929899.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
diagnostyka uszkodzeń
wykrywanie zmian
obwód zamknięty
parametryzacja
active fault diagnosis
parametric faults
stochastic change detection
closed loop systems
parametrization
Opis:
The focus of this paper is on stochastic change detection applied in connection with active fault diagnosis (AFD). An auxiliary input signal is applied in AFD. This signal injection in the system will in general allow us to obtain a fast change detection/isolation by considering the output or an error output from the system. The classical cumulative sum (CUSUM) test will be modified with respect to the AFD approach applied. The CUSUM method will be altered such that it will be able to detect a change in the signature from the auxiliary input signal in an (error) output signal. It will be shown how it is possible to apply both the gain and the phase change of the output signal in CUSUM tests. The method is demonstrated using an example.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 4; 487-496
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Możliwości wykorzystania termografii aktywnej do lokalizacji zbrojenia w elementach żelbetowych
Possibilities of using active ir thermography for localization of steel bars in reinforced concrete
Autorzy:
Noszczyk, P.
Powiązania:
https://bibliotekanauki.pl/articles/134750.pdf
Data publikacji:
2016
Wydawca:
ADVSEO
Tematy:
active thermography
non-destructive testing
material inclusions
detection of rebar
Opis:
The paper presents the possibility of using non-destructive testing with active thermography to the location of reinforcement in concrete elements. Four reinforced concrete elements in the form of beams with dimensions of 24 x 24 x 200 cm was researched. The beams had the main reinforcement with diameters sequentially: 12 mm, 16 mm, 20 mm and 25 mm. Stirrups with a diameter of 6 mm were placed every 20 cm. Lagging for the main reinforcement of test surface was 26 mm. Reinforced concrete elements were heated with an infrared lamp and thermal images were recorded periodically at intervals of 1 min. Preliminary studies have shown that detection of reinforcement in concrete elements using active thermography is possible. The rebar was visible on the thermograms from the start of the cool down phase for about 20 min after. The study contains a description of the test stand, and the tests performed. The paper also highlighted the problems encountered on the implementation of research and prospect of development active thermography as a non-destructive testing.
Źródło:
Technical Issues; 2016, 2; 39-44
2392-3954
Pojawia się w:
Technical Issues
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Emergence Angle on Acoustic Transmission in a Shallow Sea
Autorzy:
Lu, Yanyang
Yang, Kunde
Liu, Hong
Huang, Chunlong
Powiązania:
https://bibliotekanauki.pl/articles/177665.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czasopisma i Monografie PAN
Tematy:
underwater acoustic
emergence angle
transmission loss
active sonar detection
Opis:
In this study, the effect of the emergence angle of a source array on acoustic transmission in a typical shallow sea is simulated and analyzed. The formula we derived for the received signal based on the Normal Mode indicates that the signal is determined by the beamform on the modes of all sources and the samplings of all modes at the receiving depth. Two characteristics of the optimal emergence angle (OEA) are obtained and explained utilizing the aforementioned derived formula. The observed distributions of transmission loss (TL) for different sources and receivers are consistent with the obtained characteristics. The results of this study are valuable for the development and design of active sonar detection.
Źródło:
Archives of Acoustics; 2020, 45, 1; 3-9
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hand gesture recognition based on free-form contours and probabilistic inference
Autorzy:
Kasprzak, W.
Wilkowski, A.
Czapnik, K.
Powiązania:
https://bibliotekanauki.pl/articles/331308.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
śledzenie dłoni
analiza sekwencji obrazów
wnioskowanie stochastyczne
active contours
hand pose detection
hand tracking
image sequence analysis
stochastic inference
Opis:
A computer vision system is described that captures color image sequences, detects and recognizes static hand poses (i.e., 'letters') and interprets pose sequences in terms of gestures (i.e., 'words'). The hand object is detected with a double-active contour-based method. A tracking of the hand pose in a short sequence allows detecting 'modified poses', like diacritic letters in national alphabets. The static hand pose set corresponds to hand signs of a thumb alphabet. Finally, by tracking hand poses in a longer image sequence, the pose sequence is interpreted in terms of gestures. Dynamic Bayesian models and their inference methods (particle filter and Viterbi search) are applied at this stage, allowing a bi-driven control of the entire system.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 2; 437-448
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fast edge detection approach based on global optimization convex model and Split Bregman algorithm
Autorzy:
Jing, Y.
Liu, J.
Liu, Z.
Cao, H.
Powiązania:
https://bibliotekanauki.pl/articles/329158.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
edge detection
active contour
global optimization
numerical minimization
split Bregman algorithm
detekcja krawędzi
kontur aktywny
optymalizacja globalna
algorytm Bregmana
Opis:
Active contour model is a typical and effective closed edge detection algorithm, which has been widely applied in remote sensing image processing. Since the variety of the image data source, the complexity of the application background and the limitations of edge detection, the robustness and universality of active contour model are greatly reduced in the practical application of edge extraction. This study presented a fast edge detection approach based on global optimization convex model and Split Bregman algorithm. Firstly, the proposed approach defined a generalized convex function variational model which incorporated the RSF model’s principle and Chan’s global optimization idea and could get the global optimal solution. Secondly, a fast numerical minimization scheme based on split Bregman iterative algorithm is employed for overcoming drawbacks of noise and others. Finally, the curve evolves to the target boundaries quickly and accurately. The approach was applied in real special sea ice SAR images and synthetic images with noise, fuzzy boundaries and intensity inhomogeneity, and the experiment results showed that the proposed approach had a better performance than the edge detection methods based on the GMAC model and RSF model. The validity and robustness of the proposed approach were also verified.
Źródło:
Diagnostyka; 2018, 19, 2; 23-29
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kontrast filtrowany w charakteryzacji wad materiałowych metodą aktywnej termografii
Filtered contrast in defect characterization using active infrared thermography
Autorzy:
Gryś, S.
Minkina, W.
Powiązania:
https://bibliotekanauki.pl/articles/152646.pdf
Data publikacji:
2010
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
badania nieniszczące
aktywna termografia
charakteryzacja defektów
propagacja rozkładów
symulacja Monte Carlo
nondestructive testing
active thermography
defect detection and characterization
propagation of distributions
Monte Carlo simulation
Opis:
W artykule przedstawiono możliwości zastosowania "kontrastu filtrowanego" do wykrywania i charakteryzacji defektów w materiale metodą aktywnej termografii. Do wyznaczenia "kontrastu filtrowanego" nie jest wymagana znajomość obszaru referencyjnego bez defektu oraz jest mniej wrażliwy na niejednorodność napromienienia powierzchni materiału w porównaniu do klasycznych rodzajów kontrastów cieplnych. Eksperyment przeprowadzono na stanowisku wyposażonym w kamerę ThermaCAM PM 595 oraz kartę rejestracji danych. Oszacowano wpływ parametrów cieplnych badanego materiału i defektu oraz parametru filtru wygładzającego, niezbędnego do implementacji idei kontrastu filtrowanego, na niepewność estymacji głębokości defektów. W analizie zastosowano zasadę propagacji rozkładów prawdo-podobieństwa i symulację Monte Carlo.
The paper presents the possibility of the use of new kind of thermal contrast in subsurface defects detection [1,3-6]. It allows detecting defects taking advantages [2,6] of an active thermography - Table 1. In opposition to known definitions of the thermal contrast [1], a defect-free area is no necessary and this contrast is less sensitive to nonuniformity of heat disposal to the material surface. The measurements were per-formed on a setup presented in Fig. 1 [7]. A special sample of Plexiglas was made with bottom-holes simulating defects - Figs 2 and 3. The material parameters - Table 2, were taken from [1]. The step heating was chosen as heat excitation. Exemplary, raw and processed thermograms for symmetrical and asymmetrical heat disposal are shown in Figs 4 and 5. The influence of the parameter B of the smoothing filter, thermal parameters of the tested material and defect on expanded uncertainty of determination of defect depth were analyzed. Due to significant complexity of the model the numerical method, i.e. Monte Carlo simulation was applied. According to this procedure [9,10] an expectation and 95% coverage intervals are presented in Tab 4 and 5. In the Table 6 there is fixed if the 95% coverage interval contains the true value of depth. For the inspected sample, B=10, and assumed accuracy of evaluation of diffusivity [8] of Plexiglas, the accuracy of the method does not exceed 20%. The optimal value of B corresponds to the diameter of defects. This aspect will be examined in further work.
Źródło:
Pomiary Automatyka Kontrola; 2010, R. 56, nr 8, 8; 893-896
0032-4140
Pojawia się w:
Pomiary Automatyka Kontrola
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Diagnostic methods of detecting defects within the material with the use of active infrared thermovision
Autorzy:
Grochalski, K.
Peta, K.
Powiązania:
https://bibliotekanauki.pl/articles/94152.pdf
Data publikacji:
2017
Wydawca:
Politechnika Poznańska. Wydawnictwo Politechniki Poznańskiej
Tematy:
active thermovision
thermal images analysis
diagnostic
external forcing heat
defect detection
termowizja aktywna
analiza obrazów termowizyjnych
diagnostyka
zewnętrzne wymuszanie ciepła
wykrywanie usterek
Opis:
Article presents the methods of detecting defects within material with the use of active infrared thermovision. During the study ABS and PVC samples were used inside which internal structure defects and defects of glue conjunction between components were modeled. During combining composite materials with the use of glue joints, there is a problem with homogenous distribution of the glue layer on the surface of an element, which results in the creation of defects in joint structure and the decline of active surface of adhesion forces on the combined materials. It is then necessary to control the quality of the conjunction between the glued surfaces. The use of non-contact diagnostic methods allows to analyze a larger surface which conditions in more efficient quality control process. In the study, external heat excitation was used - optical excitation with periodic variable signal (LockIn method) and unit step excitation (Pulse method). The methods of analysis of the obtained thermograms are presented.
Źródło:
Archives of Mechanical Technology and Materials; 2017, 37; 41-44
2450-9469
Pojawia się w:
Archives of Mechanical Technology and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of thinning of homogeneous material using active thermography and classification trees
Autorzy:
Dudzik, Sebastian
Dudek, Grzegorz
Powiązania:
https://bibliotekanauki.pl/articles/1848987.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
active thermography
classification tree
defect detection and characterization
material thinning detection
Opis:
Active thermography is an efficient tool for defect detection and characterization as it does not change the properties of tested materials. The detection and characterization process involves heating a sample and then analysing the thermal response. In this paper, a long heating pulse was used on samples with a low thermal diffusivity and artificially created holes of various depths. As a result of the experiments, heating and cooling curves were obtained. These curves, which describe local characteristics of the material, are recognized using a classification tree and divided into categories depending on the material thickness (hole depths). Two advantages of the proposed use of classification trees are: an in-built mechanism for feature selection and a strong reduction in the dimensions of the pattern. Based on the experimental study, it can be concluded that classification trees are a useful tool for the thinning detection of homogeneous material.
Źródło:
Metrology and Measurement Systems; 2021, 28, 1; 89-105
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł

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