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Wyświetlanie 1-15 z 39
Tytuł:
Test signal generation for service diagnosis based on local structural properties
Autorzy:
Ungermann, M.
Lunze, J.
Schwarzmann, D.
Powiązania:
https://bibliotekanauki.pl/articles/331378.pdf
Data publikacji:
2012
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
analiza strukturalna
generowanie sygnału
właściwości strukturalne
structural analysis
service diagnosis
active diagnosis
test generation
Opis:
The paper presents a new approach to the generation of test signals used in service diagnosis. The tests make it possible to isolate faults, which are isolable only if the system is brought into specific operating points. The basis for the test signal selection is a structure graph that represents the couplings among the external and internal signals of the system and the fault signals. Graph-theoretic methods are used to identify edges that disappear under certain operating conditions and prevent a fault from changing the system behavior at this operating point. These operating conditions are identified by validuals, which are indicators obtained during the graph-theoretic analysis. The test generation method is illustrated by a process engineering example.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2012, 22, 1; 55-65
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
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:
A new approach to multiple fault diagnosis: A combination of diagnostic matrices, graphs, algebraic and rule-based models. The case of two-layer models
Autorzy:
Ligęza, A.
Kościelny, J. M.
Powiązania:
https://bibliotekanauki.pl/articles/929906.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
diagnoza zautomatyzowana
macierz diagnostyczna
zasady diagnostyczne
diagnoza na bazie modelu
diagnoza na bazie spójności
automated diagnosis
diagnostic matrix
diagnostic rules
model-based diagnosis
consistency-based diagnosis
Opis:
The diagnosis of multiple faults is significantly more difficult than singular fault diagnosis. However, in realistic industrial systems the possibility of simultaneous occurrence of multiple faults must be taken into account. This paper investigates some of the limitations of the diagnostic model based on the simple binary diagnostic matrix in the case of multiple faults. Several possible interpretations of the diagnostic matrix with rule-based systems are provided and analyzed. A proposal of an extension of the basic, single-level model based on diagnostic matrices to a two-level one, founded on causal analysis and incorporating an OR and an AND matrix is put forward. An approach to the diagnosis of multiple faults based on inconsistency analysis is outlined, and a refinement procedure using a qualitative model of dependencies among system variables is sketched out.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 4; 465-476
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
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:
SMAC-FDI: A single model active fault detection and isolation system for unmanned aircraft
Autorzy:
Ducard, G. J. J.
Powiązania:
https://bibliotekanauki.pl/articles/331366.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault detection
fault isolation
unmanned aerial vehicle
Kalman filtering
computationally efficient diagnosis system
active fault diagnosis
artificial excitation system
detekcja uszkodzeń
lokalizacja uszkodzeń
bezzałogowiec
filtracja Kalmana
diagnostyka uszkodzeń
układ wzbudzenia
Opis:
This article presents a single model active fault detection and isolation system (SMAC-FDI) which is designed to efficiently detect and isolate a faulty actuator in a system, such as a small (unmanned) aircraft. This FDI system is based on a single and simple aerodynamic model of an aircraft in order to generate some residuals, as soon as an actuator fault occurs. These residuals are used to trigger an active strategy based on artificial exciting signals that searches within the residuals for the signature of an actuator fault. Fault isolation is carried out through an innovative mechanism that does not use the previous residuals but the actuator control signals directly. In addition, the paper presents a complete parameter-tuning strategy for this FDI system. The novel concepts are backed-up by simulations of a small unmanned aircraft experiencing successive actuator failures. The robustness of the SMAC-FDI method is tested in the presence of model uncertainties, realistic sensor noise and wind gusts. Finally, the paper concludes with a discussion on the computational efficiency of the method and its ability to run on small microcontrollers.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2015, 25, 1; 189-201
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault diagnosis of a water for injection system using enhanced structural isolation
Autorzy:
Laursen, M.
Blanke, M.
Düştegör, D.
Powiązania:
https://bibliotekanauki.pl/articles/929918.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
analiza strukturalna
lokalizacja uszkodzeń
diagnostyka uszkodzeń
dopasowanie
structural analysis
fault isolation
fault diagnosis
matching
Opis:
A water for injection system supplies chilled sterile water as a solvent for pharmaceutical products. There are ultimate requirements for the quality of the sterile water, and the consequence of a fault in temperature or in flow control within the process may cause a loss of one or more batches of the production. Early diagnosis of faults is hence of considerable interest for this process. This study investigates the properties of multiple matchings with respect to isolability, and it suggests to explore the topologies of multiple use-modes for the process and to employ active techniques for fault isolation to enhance structural isolability of faults. The suggested methods are validated on a high-fidelity simulation of the process.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 4; 593-603
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Decentralized and distributed active fault diagnosis: Multiple model estimation algorithms
Autorzy:
Straka, Ondřej
Punčochář, Ivo
Powiązania:
https://bibliotekanauki.pl/articles/330423.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault diagnosis
large scale system
multiple model
diagnostyka błędu
system dużej skali
model wieloskładnikowy
Opis:
The paper focuses on active fault diagnosis (AFD) of large scale systems. The multiple model framework is considered and two architectures are treated: the decentralized and the distributed one. An essential part of the AFD algorithm is state estimation, which must be supplemented with a mechanism to achieve feasible implementation in the multiple model framework. In the paper, the generalized pseudo Bayes and interacting multiple model estimation algorithms are considered. They are reformulated for a given model of a large scale system. Performance of both AFD architectures is analyzed for different combinations of multiple model estimation algorithms using a numerical example.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 2; 239-249
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Advances in model-based fault diagnosis with evolutionary algorithms and neural networks
Autorzy:
Witczak, M.
Powiązania:
https://bibliotekanauki.pl/articles/908460.pdf
Data publikacji:
2006
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
diagnostyka uszkodzeń
algorytmy ewolucyjne
sieci neuronowe
odporność
fault diagnosis
evolutionary algorithms
neural networks
robustness
Opis:
Challenging design problems arise regularly in modern fault diagnosis systems. Unfortunately, the classical analytical techniques often cannot provide acceptable solutions to such difficult tasks. This explains why soft computing techniques such as evolutionary algorithms and neural networks become more and more popular in industrial applications of fault diagnosis. The main objective of this paper is to present recent developments regarding the application of evolutionary algorithms and neural networks to fault diagnosis. In particular, a brief introduction to these computational intelligence paradigms is presented, and then a review of their fault detection and isolation applications is performed. Close attention is paid to techniques that integrate the classical and soft computing methods. A selected group of them is carefully described in the paper. The performance of the presented approaches is illustrated with the use of the DAMADICS fault detection benchmark that deals with a valve actuator.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2006, 16, 1; 85-99
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for sensor placement taking into account diagnosability criteria
Autorzy:
Yassine, A. A.
Ploix, S.
Flaus, J.-M.
Powiązania:
https://bibliotekanauki.pl/articles/929893.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
diagnostyka uszkodzeń
diagnozowalność
położenie sensora
modelowanie strukturalne
fault diagnosis
diagnosability
sensor placement
structural modelling
Opis:
This paper presents a new approach to sensor placement based on diagnosability criteria. It is based on the study of structural matrices. Properties of structural matrices regarding detectability, discriminability and diagnosability are established in order to be used by sensor placement methods. The proposed approach manages any number of constraints modelled by linear or nonlinear equations and it does not require the design of analytical redundancy relations. Assuming that a constraint models a component and that the cost of the measurement of each variable is defined, a method determining sensor placements satisfying diagnosability specifications, where all the diagnosable, discriminable and detectable constraint sets are specified, is proposed. An application example dealing with a dynamical linear system is presented.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 4; 497-512
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mode set focused hybrid estimation
Autorzy:
Rienmüller, T.
Hofbaur, M.
Travé-Massuyès, L.
Bayoudh, M.
Powiązania:
https://bibliotekanauki.pl/articles/329975.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
hybrid system
fault detection
fault diagnosis
monitoring
estimation
system hybrydowy
detekcja uszkodzeń
diagnostyka uszkodzeń
estymacja
Opis:
Estimating the state of a hybrid system means accounting for the mode of operation or failure and the current state of the continuously valued entities concurrently. Existing hybrid estimation schemes try to overcome the problem of an exponentially growing number of possible mode-sequence/continuous-state combinations by merging hypotheses and/or deducing likelihood measures to identify tractable sets of the most likely hypotheses. However, they still suffer from unnecessarily high computational costs as the number of possible modes increases. Hybrid diagnosis schemes, on the other hand, estimate the current mode of operation/failure only, thus leaving the continuous evolution of the system implicit. This paper proposes a novel scheme that uses a combination of both the approaches in order to define posterior transition probabilities between the specified modes of the hybrid system, hence focusing better on relevant hypotheses. In order to demonstrate the effectiveness of the proposed method, the algorithm is applied to a satellite attitude control system and compared with existing hybrid estimation/diagnosis schemes, such as the Interacting Multiple Model (IMM) algorithm, a purely parity based method (HyDiag), and an existing hybrid Mode Estimation (hME) algorithm.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2013, 23, 1; 131-144
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Hamiltonian approach to fault isolation in a planar vertical take-off and landing aircraft model
Autorzy:
Rodriguez-Alfaro, L. H.
Alcorta-Garcia, E.
Lara, D.
Romero, G.
Powiązania:
https://bibliotekanauki.pl/articles/330664.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
Hamiltonian method
observer
fault diagnosis
nonlinear system
UAVs
metoda Hamiltonowska
obserwator
diagnoza uszkodzeń
układ nieliniowy
Opis:
The problem of fault detection and isolation in a class of nonlinear systems having a Hamiltonian representation is considered. In particular, a model of a planar vertical take-off and landing aircraft with sensor and actuator faults is studied. A Hamiltonian representation is derived from an Euler–Lagrange representation of the system model considered. In this form, nonlinear decoupling is applied in order to obtain subsystems with (as much as possible) specific fault sensitivity properties. The resulting decoupled subsystem is represented as a Hamiltonian system and observer-based residual generators are designed. The results are presented through simulations to show the effectiveness of the proposed approach.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2015, 25, 1; 65-76
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Towards robustness in neural network based fault diagnosis
Autorzy:
Patan, K.
Witczak, M.
Korbicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/929913.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
diagnostyka uszkodzeń
odporność
sieć neuronowa dynamiczna
fault diagnosis
robustness
dynamic neural networks
GMDH neural network
Opis:
Challenging design problems arise regularly in modern fault diagnosis systems. Unfortunately, classical analytical techniques often cannot provide acceptable solutions to such difficult tasks. This explains why soft computing techniques such as neural networks become more and more popular in industrial applications of fault diagnosis. Taking into account the two crucial aspects, i.e., the nonlinear behaviour of the system being diagnosed as well as the robustness of a fault diagnosis scheme with respect to modelling uncertainty, two different neural network based schemes are described and carefully discussed. The final part of the paper presents an illustrative example regarding the modelling and fault diagnosis of a DC motor, which shows the performance of the proposed strategy.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2008, 18, 4; 443-454
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Segmentation of the melanoma lesion and its border
Autorzy:
Surówka, Grzegorz
Ogorzałek, Maciej
Powiązania:
https://bibliotekanauki.pl/articles/2172123.pdf
Data publikacji:
2022
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
computer aided diagnosis
DBSCAN
malignant melanoma
region growing
diagnoza wspomagana komputerowo
czerniak złośliwy
rozrost regionów
Opis:
Segmentation of the border of the human pigmented lesions has a direct impact on the diagnosis of malignant melanoma. In this work, we examine performance of (i) morphological segmentation of a pigmented lesion by region growing with the adaptive threshold and density-based DBSCAN clustering algorithm, and (ii) morphological segmentation of the pigmented lesion border by region growing of the lesion and the background skin. Research tasks (i) and (ii) are evaluated by a human expert and tested on two data sets, A and B, of different origins, resolution, and image quality. The preprocessing step consists of removing the black frame around the lesion and reducing noise and artifacts. The halo is removed by cutting out the dark circular region and filling it with an average skin color. Noise is reduced by a family of Gaussian filters 3×3−7×7 to improve the contrast and smooth out possible distortions. Some other filters are also tested. Artifacts like dark thick hair or ruler/ink markers are removed from the images by using the DullRazor closing images for all RGB colors for a hair brightness threshold below a value of 25 or, alternatively, by the BTH transform. For the segmentation, JFIF luminance representation is used. In the analysis (i), out of each dermoscopy image, a lesion segmentation mask is produced. For the region growing we get a sensitivity of 0.92/0.85, a precision of 0.98/0.91, and a border error of 0.08/0.15 for data sets A/B, respectively. For the density-based DBSCAN algorithm, we get a sensitivity of 0.91/0.89, a precision of 0.95/0.93, and a border error of 0.09/0.12 for data sets A/B, respectively. In the analysis (ii), out of each dermoscopy image, a series of lesion, background, and border segmentation images are derived. We get a sensitivity of about 0.89, a specificity of 0.94 and an accuracy of 0.91 for data set A, and a sensitivity of about 0.85, specificity of 0.91 and an accuracy of 0.89 for data set B. Our analyses show that the improved methods of region growing and density-based clustering performed after proper preprocessing may be good tools for the computer-aided melanoma diagnosis.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2022, 32, 4; 683--699
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fault isolability with different forms of the faults–symptoms relation
Autorzy:
Kościelny, J. M.
Syfert, M.
Rostek, K.
Sztyber, A.
Powiązania:
https://bibliotekanauki.pl/articles/330460.pdf
Data publikacji:
2016
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
fault diagnosis
fault isolation
symptom sequence
information system
diagnostyka uszkodzeń
lokalizacja uszkodzeń
sekwencja symptomów
system informacyjny
Opis:
The definitions and conditions for fault isolability of single faults for various forms of the diagnostic relation are reviewed. Fault isolability and unisolability on the basis of a binary diagnostic matrix are analyzed. Definitions for conditional and unconditional isolability and unisolability on the basis of a fault information system (FIS), symptom sequences and directional residuals are formulated. General definitions for conditional and unconditional isolability and unisolability in the cases of simultaneous evaluation of diagnostic signal values and a sequence of symptoms are provided. A comprehensive example is discussed.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2016, 26, 4; 815-826
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bounded-abstaining classification for breast tumors in imbalanced ultrasound images
Autorzy:
Guan, Hongjiao
Zhang, Yingtao
Cheng, Heng-Da
Tang, Xianglong
Powiązania:
https://bibliotekanauki.pl/articles/330479.pdf
Data publikacji:
2020
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
breast ultrasound image
reliable diagnosis
abstaining classification
imbalanced dataset
ultrasonografia piersi
diagnoza wiarygodna
zbiór danych niezrównoważony
Opis:
Computer-aided breast ultrasound (BUS) diagnosis remains a difficult task. One of the challenges is that imbalanced BUS datasets lead to poor performance, especially with regard to low accuracy in the minority (malignant tumor) class. Missed diagnosis of malignant tumors can cause serious consequences, such as delaying treatment and increasing the risk of death. Moreover, many diagnosis methods do not consider classification reliability; thus, some classifications may have a large uncertainty. To resolve such problems, a bounded-abstaining classification model is proposed. It maximizes the area under the ROC curve (AUC) under two abstention constraints. A total of 219 (92 malignant and 127 benign) BUS images are collected from the First Affiliated Hospital of Harbin Medical University, China. The experiment tests BUS datasets of three imbalance levels, and the performance contours are analyzed. The results demonstrate that AUC-rejection curves are less affected by class imbalance than accuracy-rejection curves. Compared with the state-of-the-art, the proposed method yields a significantly larger AUC and G-mean using imbalanced BUS datasets.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2020, 30, 2; 325-336
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 39

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