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Wyświetlanie 1-15 z 132
Tytuł:
Two heuristic alghorithms for test point selection in analog circuit diagnoses
Autorzy:
Pułka, A.
Powiązania:
https://bibliotekanauki.pl/articles/221005.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuit diagnosis
fault diagnosis
testing
search methods
heuristic optimization
Opis:
The paper presents a heuristic approach to the problem of analog circuit diagnosis. Different optimization techniques in the field of test point selection are discussed. Two new algorithms: SALTO and COSMO have been introduced. Both searching procedures have been implemented in a form of the expert system in PROLOG language. The proposed methodologies have been exemplified on benchmark circuits. The obtained results have been compared to the others achieved by different approaches in the field and the benefits of the proposed methodology have been emphasized. The inference engine of the heuristic algorithms has been presented and the expert system knowledge-base construction discussed.
Źródło:
Metrology and Measurement Systems; 2011, 18, 1; 115-128
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The possibilities of early fault detection of engines
Autorzy:
Filipczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/244750.pdf
Data publikacji:
2013
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
fault diagnosis
faults of engine
Opis:
The results of investigation of 1,9 TDI engine (285 Nm, 85 kW, type AJM without any modification) equipped with injection units supplied conventional diesel fuel (ON) or B100 fuel (RME) have been presented in article. Investigations have been realized at the engine speed of 2000 rpm and variable load within the range of 0 to 275 Nm. The pressure, temperature and heat release velocity runs have been subjected to analysis. Particular attention has been paid to the release of the heat used for the effective work and internal energy increase of the working medium (enthalpy) during combustion inside the engine cylinder versus the crank angle for both investigated fuels. It was found among the others that mentioned fuels differ in the heat release, heat velocity and the maximal combustion temperature, which for the B100 fuel is bigger than for the conventional diesel fuel. Bigger combustion dynamics of tested biofuel (compared with standard diesel fuel) results higher concentrations of Nitrogen Oxides NOx in exhaust gases. The easiest way is of course the use of the later start of fuel injection biofuels and/or increase the exhaust gas recirculation EGR. These treatments, however, result in a worsening of the energy performance of the engine. It was concluded also that the combustion of RME works properly at higher engine loads. Then reduce the negative difference between the combustion of biofuel (RME) and standard Diesel fuel.
Źródło:
Journal of KONES; 2013, 20, 4; 79-84
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A key metric and its calculation models for a continuous diagnosis capability based on a dependency matrix
Autorzy:
Shi, J.-Y.
Lin, X.-G.
Shi, M.
Powiązania:
https://bibliotekanauki.pl/articles/221741.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
fault diagnosis
dependency matrix
measurement
Opis:
This paper is devoted to measuring the continuous diagnosis capability of a system. A key metric and its calculation models are proposed enabling us to measure the continuous diagnosis capability of a system directly without establishing and searching the sequential fault tree (SFT) of the system. At first a description of a D matrix is given and its metric is defined to determine the weakness of a continuous diagnosis. Then based on the definition of a sequential fault combination, a sequential fault tree (SFT) is defined with its establishment process summarized. A key SFT metric is established to measure the continuous diagnosis capability of a system. Two basic types of dependency graphical models (DGMs) and one combination type of DGM are selected for characteristics analysis and establishment of metric calculation models. Finally, both the SFT searching method and direct calculation method are applied to two designs of one type of an auxiliary navigation equipment, which shows the high efficiency of the direct calculation method.
Źródło:
Metrology and Measurement Systems; 2012, 19, 3; 509-520
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear Trend Analysis of Mill Fan System Vibrations for Predictive Maintenance and Diagnostics
Autorzy:
Hadjiski, M. B.
Doukovska, L. A.
Kojnov, S. L.
Powiązania:
https://bibliotekanauki.pl/articles/226410.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
technical diagnosis
fault diagnosis
predictive maintenance
manufacturing execution system (MES)
enterprise resource planning (ERP)
Opis:
Present paper considers nonlinear trend analysis for diagnostics and predictive maintenance. The subject is a device from Maritsa East 2 thermal power plant a mill fan. The choice of the given power plant is not occasional. This is the largest thermal power plant on the Balkan Peninsula. Mill fans are main part of the fuel preparation in the coal fired power plants. The possibility to predict eventual damages or wear out without switching off the device is significant for providing faultless and reliable work avoiding the losses caused by planned maintenance. This paper addresses the needs of the Maritsa East 2 Complex aiming to improve the ecological parameters of the electro energy production process.
Źródło:
International Journal of Electronics and Telecommunications; 2012, 58, 4; 351-356
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
From structural analysis to observer-based residual generation for fault detection
Autorzy:
Pröll, S.
Lunze, J.
Jarmolowitz, F.
Powiązania:
https://bibliotekanauki.pl/articles/330986.pdf
Data publikacji:
2018
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault diagnosis
structural analysis
observer based diagnosis
diagnosability analysis
diagnostyka uszkodzeń
analiza strukturalna
analiza diagnostyczna
Opis:
This paper combines methods for the structural analysis of bipartite graphs with observer-based residual generation. The analysis of bipartite structure graphs leads to over-determined subsets of equations within a system model, which make it possible to compute residuals for fault detection. In observer-based diagnosis, by contrast, an observability analysis finds observable subsystems, for which residuals can be generated by state observers. This paper reveals a fundamental relationship between these two graph-theoretic approaches to diagnosability analysis and shows that for linear systems the structurally over-determined set of model equations equals the output connected part of the system. Moreover, a condition is proved which allows us to verify structural observability of a system by means of the corresponding bipartite graph. An important consequence of this result is a comprehensive approach to fault detection systems, which starts with finding the over-determined part of a given system by means of a bipartite structure graph and continues with designing an observer-based residual generator for the fault-detectable subsystem found in the first step.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2018, 28, 2; 233-245
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Identification of Circuit Parameters for the Specified or Measured Performances
Autorzy:
Rutkowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/226920.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuits
parameter identification
fault diagnosis
Opis:
Extension of the method of analog circuit parameter identification for the specified design performances, originally presented by the same author in 1982, is described. These parameters are designated by means of PSpice simulation of the adjoint circuit to the original one. In this adjoint circuit, elements of the original circuit, described by the sized parameters, are replaced by controlled sources. Each such source is controlled by the differential voltage or current, difference between the calculated voltage or current and the specified one, with infinitely large gain. The method is applicable to both linear and nonlinear DC circuits and AC circuits and can be used in many fields of analog circuit design, such as: finding of acceptability region, analog fault diagnosis, postproduction identification and tuning. In the later cases, design performances are replaced by measurements of Circuit Under Test (CUT). Simplicity, extremely low computational complexity and high accuracy are the main benefits of the proposed, basic Circuit Theory based, approach - the solution is found after a single PSpice simulation. For better understanding of the presented methodology, five practical examples are discussed.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 95-100
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Aspects of Fault Diagnosis of Nonlinear Analog Circuits
Autorzy:
Tadeusiewicz, M.
Hałgas, S.
Kuczyński, A.
Powiązania:
https://bibliotekanauki.pl/articles/226274.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuits
fault diagnosis
local and global diagnosis
multiple soft fault
nonlinear circuits
single hard faults
Opis:
The paper is focused on nonlinear analog circuits, with the special attention paid to circuits comprising bipolar and MOS transistors manufactured in micrometer and submicrometer technology. The problem of fault diagnosis of this class of circuits is discussed, including locating faulty elements and evaluating their parameters. The paper deals with multiple parametric fault diagnosis using the simulation after test approach as well as detection and location of single catastrophic faults, using the simulation before test approach. The discussed methods are based on diagnostic test, leading to a system of nonlinear algebraic type equations, which are not given in explicit analytical form. An important and new aspect of the fault diagnosis is finding multiple solutions of the test equation, i.e. several sets of the parameters values that meet the test. Another new problems in this area are global fault diagnosis of technological parameters in CMOS circuits fabricated in submicrometer technology and testing the circuits having multiple DC operating points. To solve these problems several methods have been recently developed, which employ different concepts and mathematical tools of nonlinear analysis. In this paper they are sketched and illustrated. All the discussed methods are based on the homotopy (continuation) idea. It is shown that various versions of homotopy and combinations of the homotopy with some other mathematical algorithms lead to very powerful tools for fault diagnosis of nonlinear analog circuits. To trace the homotopy path which allows finding multiple solutions, the simplicial method, the restart method, the theory of linear complementarity problem and Lemke’s algorithm are employed. For illustration four numerical examples are given.
Źródło:
International Journal of Electronics and Telecommunications; 2015, 61, 1; 83-93
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of bearings based on SSWT, bayes optimisation and CNN
Autorzy:
Yan, Guohua
Hu, Yihuai
Shi, Qingguo
Powiązania:
https://bibliotekanauki.pl/articles/34610052.pdf
Data publikacji:
2023
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
fault diagnosis
bearing
PMSM
bayesian optimisation
CNN
Opis:
Bearings are important components of rotating machinery and transmission systems, and are often damaged by wear, overload and shocks. Due to the low resolution of traditional time-frequency analysis for the diagnosis of bearing faults, a synchrosqueezed wavelet transform (SSWT) is proposed to improve the resolution. An improved convolutional neural network fault diagnosis model is proposed in this paper, and a Bayesian optimisation method is applied to automatically adjust the structure and hyperparameters of the model to improve the accuracy of bearing fault diagnosis. Experimental results from the accelerated life testing of bearings show that the proposed method is able to accurately identify various types of bearing fault and the different status of these faults under complex running conditions, while achieving very good generalisation ability.
Źródło:
Polish Maritime Research; 2023, 3; 132-141
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A model-based approach to fault-tolerant control
Autorzy:
Niemann, H. H.
Powiązania:
https://bibliotekanauki.pl/articles/331380.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
sterowanie tolerujące uszkodzenia
architektura sterownika
diagnostyka uszkodzeń
fault-tolerant control
controller architecture
fault diagnosis
active fault diagnosis
controller switching
Opis:
A model-based controller architecture for Fault-Tolerant Control (FTC) is presented in this paper. The controller architecture is based on a general controller parameterization. The FTC architecture consists of two main parts, a Fault Detection and Isolation (FDI) part and a controller reconfiguration part. The theoretical basis for the architecture is given followed by an investigation of the single parts in the architecture. It is shown that the general controller parameterization is central in connection with both fault diagnosis as well as controller reconfiguration. Especially in relation to the controller reconfiguration part, the application of controller parameterization results in a systematic technique for switching between different controllers. This also allows controller switching using different sets of actuators and sensors.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 1; 67-86
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research on SDG fault diagnosis of ocean shipping boiler system based on fuzzy granular computing under data fusion
Autorzy:
Zhu, Y.
Geng, L.
Powiązania:
https://bibliotekanauki.pl/articles/258772.pdf
Data publikacji:
2018
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
granular computing
symbolic digraph
fault diagnosis
fuzzy theory
Opis:
The research work in this paper belongs to the application of granular computing, graph theory and its application in fault detection and diagnosis. It is a cross cutting and frontier research field in computer science, information science and graph theory. The results of this paper are of great significance to the application of the fault detection and diagnosis of the ocean boilers system. This research combines granular computing theory and signed directed graph, and proposes a new method of fault diagnosis, and applies it to the fault diagnosis of ocean ship boiler system.
Źródło:
Polish Maritime Research; 2018, S 2; 92-97
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A convolutional neural network-based method of inverter fault diagnosis in a ship’s DC electrical system
Autorzy:
Yan, Guohua
Hu, Yihuai
Shi, Qingguo
Powiązania:
https://bibliotekanauki.pl/articles/32898224.pdf
Data publikacji:
2022
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
multi-energy hybrid ships
inverters
fault diagnosis
CNN
Opis:
Multi-energy hybrid ships are compatible with multiple forms of new energy, and have become one of the most important directions for future developments in this field. A propulsion inverter is an important component of a hybrid DC electrical system, and its reliability has great significance in terms of safe navigation of the ship. A fault diagnosis method based on one-dimensional convolutional neural network (CNN) is proposed that considers the mutual influence between an inverter fault and a limited ship power grid. A tiled voltage reduction method is used for one-to-one correspondence between the inverter output voltage and switching combinations, followed by a combination of a global average pooling layer and a fully connected layer to reduce the model overfitting problem. Finally, fault diagnosis is verified by a Softmax layer with good anti-interference performance and accuracy.
Źródło:
Polish Maritime Research; 2022, 4; 105-114
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of analog circuit based on wavelet transform and neural network
Autorzy:
Wang, Hui
Powiązania:
https://bibliotekanauki.pl/articles/141368.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuit
fault diagnosis
neural network
wavelet transform
Opis:
Analog circuits need more effective fault diagnosis methods. In this study, the fault diagnosis method of analog circuits was studied. The fault feature vectors were extracted by a wavelet transform and then classified by a generalized regression neural network (GRNN). In order to improve the classification performance, a wolf pack algorithm (WPA) was used to optimize the GRNN, and a WPA-GRNN diagnosis algorithm was obtained. Then a simulation experiment was carried out taking a Sallen–Key bandpass filter as an example. It was found from the experimental results that the WPA could achieve the preset accuracy in the eighth iteration and had a good optimization effect. In the comparison between the GRNN, genetic algorithm (GA)-GRNN and WPA-GRNN, the WPA-GRNN had the highest diagnostic accuracy, and moreover it had high accuracy in diagnosing a single fault than multiple faults, short training time, smaller error, and an average accuracy rate of 91%. The experimental results prove the effectiveness of the WPA-GRNN in fault diagnosis of analog circuits, which can make some contributions to the further development of the fault diagnosis of analog circuits.
Źródło:
Archives of Electrical Engineering; 2020, 69, 1; 175-185
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The identification of piston-cylinder clearance using time-frequency methods
Autorzy:
Flekiewicz, M.
Fabiś, P.
Madej, H.
Powiązania:
https://bibliotekanauki.pl/articles/245755.pdf
Data publikacji:
2009
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
fault diagnosis
engine vibration
Gabor Spectrogram
Adaptive Spectrogram
Opis:
A fault recognition technique for the internal combustion engines using time-frequency representations of vibration signal has been presented in this paper. Engine block vibration results as a sum of many excitations mainly connected with engine speed and their intensity increases with the appearance of a fault or in case ofhigher engine elements wearing. In this paper an application of acceleration signals for the estimation of the influence of piston skirt clearance on diesel engine block vibrations has been described. Engine body accelerations registered for three simulated cases representing piston skirt clearance variations were an object of preliminary analysis. The presented procedures were applied to vibration and pressure signals acquired for a 0.5 dm3 Ruggerini, air cooled diesel engine. reciprocating machines are difficult to diagnose using traditional frequency domain techniques due to the fact they generale transient vibrations. In the experiments that were conducted Gabor Analysis and Adaptive Spectrogram has been chosen The Gabor spectrogram is a powerful tool for on-line monitoring and diagnosis of combustion process. There are important features of the vibration signal that are sensitive to the change of IC engine condition. For that reason the DWT transform was applied. Based on the results, authors propose detection and piston skirt clearance monitoring algorithm.
Źródło:
Journal of KONES; 2009, 16, 4; 93-103
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Induction motor fault classification via entropy and column correlation features of 2D represented vibration data
Autorzy:
Basaran, Murat
Fidan, Mehmet
Powiązania:
https://bibliotekanauki.pl/articles/1841827.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Tematy:
entropy
fault diagnosis
support vector machines
wavelet transforms
Opis:
Due to long-term use under challenging conditions, the sub-elements of induction motors may suffer certain defects over time. Such defects impair the vibration characteristics of the motors in different ways, depending on the type of defect. Therefore, the change in vibration characteristic provides indicators about the fault type and can be used in preventive maintenance strategies to ensure safe operation of the system. In this work, discrete-time vibration data were transformed into 2-dimensional grey-level images and decomposed into individual components by the Wavelet decomposition method. Features based on entropy and column correlation were extracted from these components and used to classify motor faults by using the Support Vector Machine method implemented by using the Sequential Minimal Optimisation algorithm. When the selected classifier is compared with other popular Machine Learning algorithms, it is observed that motor faults are more successfully classified, and these observations are presented in detail with comparative classification performance results.
Źródło:
Eksploatacja i Niezawodność; 2021, 23, 1; 132-142
1507-2711
Pojawia się w:
Eksploatacja i Niezawodność
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Multiple soft fault diagnosis of BJT circuits
Autorzy:
Tadeusiewicz, M.
Hałgas, S.
Powiązania:
https://bibliotekanauki.pl/articles/221281.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
analog circuits
BJT circuits
fault diagnosis
multiple faults
Opis:
This paper deals with multiple soft fault diagnosis of nonlinear analog circuits comprising bipolar transistors characterized by the Ebers-Moll model. Resistances of the circuit and beta forward factor of a transistor are considered as potentially faulty parameters. The proposed diagnostic method exploits a strongly nonlinear set of algebraic type equations, which may possess multiple solutions, and is capable of finding different sets of the parameters values which meet the diagnostic test. The equations are written on the basis of node analysis and include DC voltages measured at accessible nodes, as well as some measured currents. The unknown variables are node voltages and the parameters which are considered as potentially faulty. The number of these parameters is larger than the number of the accessible nodes. To solve the set of equations the block relaxation method is used with different assignments of the variables to the blocks. Next, the solutions are corrected using the Newton-Raphson algorithm. As a result, one or more sets of the parameters values which satisfy the diagnostic test are obtained. The proposed approach is illustrated with a numerical example.
Źródło:
Metrology and Measurement Systems; 2014, 21, 4; 663-674
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 132

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