Impact of fractional filter in PI control loop applied to induction motor speed drive

Introduction. One of the main problems of electrical machine control systems is to obtain a satisfactory performance in the rejection of load disturbances, as well as in the set-point tracking tasks. Generally, the development of control algorithms does not take into account the presence of noise. Appropriate filtering is, therefore, essential to reduce the impact of noise on the output of the controller, in addition to the machine output. Recently, there has been a great tendency toward using fractional calculus to solve engineering problems. The filtering is one of the fields in which fractional calculus has received great attention. The importance of filters in signal processing and other engineering areas is unquestionable Novelty. The proposed work is intended to be a contribution in the recent works conducted on the influence of the fractional filtering on the control robustness of induction machines control. Purpose. The main contribution of this research is the application of fractional filtering to the standard PI control loop for an induction motor speed drive. Methods. In order to assess its impact and benefit, different structures for introducing the filters are investigated, A first order filter is considered in different positions, whether before or after the controller or even in both positions at the same time, with a noise source. A review of the index performance evolution (the Integral Square Error, Integral Absolute Error and Integral Time Absolute Error) has allowed a configuration design of the filter. Results. Intensive simulations were performed with a control setup using integer and fractional order filters, which permitted to conclude that the fractional filters give better performance indices compared to the integer one and thus improve the dynamic characteristics of the system.Вступ. Однією з основних проблем систем керування електричними машинами є отримання задовільних характеристик при придушенні збурень навантаження, а також завдання відстеження уставок. Зазвичай, при розробці алгоритмів керування наявність шуму не враховується. Тому потрібна відповідна фільтрація для зниження впливу шуму на вихідний сигнал контролера на додаток до вихідного сигналу машини. Останнім часом спостерігається чітка тенденція до використання дробового обчислення для вирішення інженерних завдань. Фільтрація – це одна з областей, в якій дрібному обчисленню приділяється велика увага. Важливість фільтрів у обробці сигналів та інших галузях техніки незаперечна. Новизна. Запропонована робота покликана стати внеском у недавні роботи, присвячені впливу дробової фільтрації на надійність керування асинхронними машинами. Мета. Основним внеском цього дослідження є застосування дробової фільтрації до стандартного контуру ПІ-регулювання для приводу швидкості асинхронного двигуна. Методи. Щоб оцінити його вплив та користь, досліджуються різні конструкції для введення фільтрів. Фільтр першого порядку розглядається в різних положеннях до або після контролера або навіть в обох положеннях одночасно з джерелом шуму. Огляд розвитку показників ефективності (інтегральна квадратична помилка, інтегральна абсолютна помилка та інтегральна абсолютна помилка за часом) дозволив розробити конфігурацію фільтра. Результати. Значний обсяг моделювання був проведений з налаштуванням керування з використанням фільтрів цілочисельного та дробового порядку, що дозволило зробити висновок, що дробові фільтри дають кращі показники ефективності порівняно з цілочисельним і таким чином покращують динамічні характеристики системи

Phenotypic and molecular detection of biofilm formation in staphylococcus aureus Isolated from Different Sources in Algeria

Staphylococcus aureus is an opportunistic bacterium causing a wide variety of diseases. Biofilm formation of Staphylococcus aureusis of primary public and animal health concern. The purposes of the present study were to investigate the ability of Staphylococcus aureus isolated from animals, humans, and food samples to form biofilms and to screen for the presence of biofilm-associated and regulatory genes. In total, 55 Staphylococcus aureusisolated from sheep mastitis cases (n=28), humans (n = 19), and from food matrices (n = 8) were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The ability of Staphylococcus aureus for slime production and biofilm formation was determined quantitatively. A DNA microarray examination was performed to detect adhesion genes (icaACD and biofilm-associated protein gene (bap)), genes encoding microbial surface components recognizing adhesive matrix molecules (MSCRAMMs), regulatory genes (accessory gene regulator (agr) and staphylococcal accessory regulator (sarA)), and the staphylococcal cassette chromosome mec elements (SCCmec). Out of 55 Staphylococcus aureus isolates, 39 (71.0%) and 23 (41.8%) were producing slime and biofilm, respectively. All Staphylococcus aureus strains isolated from food showed biofilm formation ability. 52.6% of the Staphylococcus aureus strains isolated from sheep with mastitis, and 17.9% of isolates from humans, were able to form a biofilm. Microarray analysis typed the Staphylococcus aureus into 15 clonal complexes. Among all Staphylococcus aureus isolates, four of the human isolates (21.1%) harbored the mecA gene (SCCmec type IV) typed into 2 clonal complexes (CC22-MRSA-IV and CC80-MRSA-IV) and were considered as methicillin-resistant, while two of them were slime-producing. None of the isolates from sheep with mastitis harbored the cna gene which is associated with biofilm production. The fnbB gene was found in 100%, 60% and 40% of biofilm-producing Staphylococcus aureus isolated from food, humans, and sheep with mastitis, respectively. Three agr groups were present and agr group III was predominant with 43.6%, followed by agr group I (38.2%), and agr group II (18.2%). This study revealed the capacity of Staphylococcus aureus isolates to form biofilms and highlighted the genetic background displayed by Staphylococcus aureus isolates from different sources in Algeria

Pathological changes of renal biopsy in Sjögren Syndrome

We are presenting the case of a 53-year-old woman with a history of Sjögren syndrome and a secondary antiphospholipid syndrome admitted at the Nephrology department for the evaluation of renal failure. The patient was initially diagnosed with tubulointerstitial nephritis and subsequently a membranoproliferative type I glomerulonephritis, secondary to cryoglobulins during the course of the disease. Repeated renal biopsies were required to confirm the diagnosis

Hypocalcemia Revealing an Enteropathy-Associated T-cell Lymphoma

Background: Neurofollicular hamartoma (NFH) is characterized histopathologically by fascicles of spindle cells that laterally delimited by hyperplastic folliculosebaceous units. It usually appears on face, near the nose or nasolabial fold. It does not manifest true neural differentiation and recently the term spindle cell predominant trichodiscoma (SCPT) has been used instead. Case Presentation: We present a case of a 40-year-old male with co-incidence of NFH and basal cell carcinoma (BCC) that the mesenchymal components of NFH were similar to SCPT but these components highly expressed S-100 protein. We also discuss about the histological aspect of the neoplasia in this report and consider the findings of other reports in association with classification of NFH by means of cellular markers and morphological resemblance to other skin hamartomas. Conclusion: Neurofollicular hamartoma is a rare benign tumor that thought to represent the cellular end of a morphological spectrum with trichodiscoma. The morphological features and expression of S100 protein in neural element helped us to achieve the diagnosis of neurofollicular hamartoma. However, variable reports of S-100 protein expression in NFH are available and further studies are needed to determine the classification of this tumor.&#160

Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts

Wavelets are a powerful tool for signal and image denoising. Most of the denoising applications in different fields were based on the thresholding of the discrete wavelet transform (DWT) coefficients. Nevertheless, DWT transform is not a time or shift invariant transform and results depend on the selected shift. Improvements on the denoising performance can be obtained using the stationary wavelet transform (SWT) (also called shift-invariant or undecimated wavelet transform). Denoising using SWT has previously shown a robust and usually better performance than denoising using DWT but with a higher computational cost. In this paper, wavelet shrinkage schemes are applied for reducing noise in synthetic and experimental non-destructive evaluation ultrasonic A-scans, using DWT and a cycle-spinning implementation of SWT. A new denoising procedure, which we call random partial cycle spinning (RPCS), is presented. It is based on a cycle-spinning over a limited number of shifts that are selected in a random way. Wavelet denoising based on DWT, SWT and RPCS have been applied to the same sets of ultrasonic A-scans and their performances in terms of SNR are compared. In all cases three well known threshold selection rules (Universal, Minimax and Sure), with decomposition level dependent selection, have been used. It is shown that the new procedure provides a good robust denoising performance, without the DWT fluctuating performance, and close to SWT but with a much lower computational cost.This work was partially supported by Spanish MCI Project DPI2011-22438San Emeterio Prieto, JL.; Rodríguez-Hernández, MA. (2015). Wavelet Cycle Spinning Denoising of NDE Ultrasonic Signals Using a Random Selection of Shifts. Journal of Nondestructive Evaluation. 34(1):1-8. https://doi.org/10.1007/s10921-014-0270-8S18341Galloway, R.L., McDermott, B.A., Thurstone, F.L.: A frequency diversity process for speckle reduction in real-time ultrasonic images. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 35, 45–49 (1988)Newhouse, V.L., Bilgutay, N.M., Saniie, J., Furgason, E.S.: Flaw-to-grain echo enhancement by split spectrum processing. Ultrasonics 20, 59–68 (1982)Karpur, P., Canelones, O.J.: Split spectrum processing: a new filtering approach for improved signal-to-noise ratio enhancement of ultrasonic signals. Ultrasonics 30, 351–357 (1992)Donoho, D.L., Johnstone, I.M.: Ideal spatial adaptation by wavelet shrinkage. Biometrika 81, 425–455 (1994)Donoho, D.L., Johnstone, I.M., Kerkyacharian, G., Picard, D.: Wavelet shrinkage: asymptotia? J. R Stat. Soc. Ser. B 57, 301–369 (1995)Donoho, D.L., Johnstone, I.M.: Adapting to unknown smoothness via wavelet shrinkage. J. Am. Stat. Assoc. 90, 1200–1224 (1995)Johnstone, I.M., Silverman, B.W.: Wavelet threshold estimators for data with correlated noise. J. R Stat. Soc. 59, 319–351 (1997)Jansen, M.: Noise Reduction by Wavelet Thresholding. Lecture Notes in Statistics 161. Springer, New York (2001). doi: 10.1007/978-1-4613-0145-5Nason, G.P., Silverman, B.W.:The stationary wavelet transform and some statistical applications. In: Antoniadis, A., Oppenheim, G. (eds.) Wavelets and Statistics. Lecture Notes in Statistics, Vol. 103, pp 281–299. Springer, New York (1995)Lang, M., Guo, H., Odegard, J.E., Burrus, C.S.: Noise reduction using an undecimated discrete wavelet transform. IEEE Signal Proc. Lett. 3, 10–12 (1996)Coifman, R.R., Donoho, D.L.: Translation-invariant de-noising. In: Antoniadis, A., Oppenheim, G. (eds.) Wavelets and Statistics. 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Control 58, 1027–1036 (2011)Shi, G.M., Chen, X.Y., Song, X.X., Qui, F., Ding, A.L.: Signal matching wavelet for ultrasonic flaw detection in high background noise. IEEE Trans. Ultrason. Ferroelectr. Freq. Control 58, 776–787 (2011)Song, S.P., Que, P.W.: Wavelet based noise suppression technique and its application to ultrasonic flaw detection. Ultrasonics 44, 188–193 (2006)Rodriguez, M.A., San Emeterio, J.L., Lázaro, J.C., Ramos, A.: Ultrasonic flaw detection in NDE of highly scattering materials using wavelet and Wigner-Ville transform processing. Ultrasonics 42, 847–851 (2004)Zhang, G.M., Zhang, S.Y., Wang, Y.W.: Application of adaptive time-frequency decomposition in ultrasonic NDE of highly-scattering materials. Ultrasonics 38, 961–964 (2000)Drai, R., Khelil, M., Benchaala, A.: Time frequency and wavelet transform applied to selected problems in ultrasonics NDE. NDT & E Int. 35, 567–572 (2002)Pardo, E., San Emeterio, J.L.: Noise reduction in ultrasonic NDT using undecimated wavelet transforms. Ultrasonics 44, e1063–e1067 (2006)Kechida, A., Drai, R., Guessoum, A.: Texture analysis for flaw detection in ultrasonic images. J. Nondestruct. Eval. 31, 108–116 (2012). doi: 10.1007/s10921-011-0126-4Rucka, M., Wilde, K.: Experimental study on ultrasonic monitoring of splitting failure in reinforced concrete. J. Nondestruct. Eval. 32, 372–383 (2013). doi: 10.1007/s10921-013-0191-yHosseini, S.M.H., Duczek, S., Gabbert, U.: Damage localization in plates using mode conversion characteristics of ultrasonic guided waves. J. Nondestruct. Eval. 33, 152–165 (2014). doi: 10.1007/s10921-013-0211-yMohammed, M.S., Ki-Seong, K.: Shift-invariant wavelet packet for signal de-noising in ultrasonic testing. Insight 54, 366–370 (2012)San Emeterio, J.L., Rodriguez-Hernandez, M.A.: Wavelet denoising of ultrasonic A-scans by random partial cycle spinning. 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Contrôle et diagnostic d’une machine à induction sans capteur en utilisant des techniques avancées d’analyse et de traitement

Les différentes techniques d'analyse et diagnostic des défauts dans la machine asynchrone sont soumises à plusieurs difficultés, en particulier lors du fonctionnement de la machine en boucle fermée. Pour cela, l'objectif de la thèse est l'exploitation des méthodes fiables de détection des défauts ou des anomalies affectant les signaux mesurés en régimes stationnaires et non-stationnaires de la machine asynchrone. Les défauts considérés sont les cassures des barres rotoriques, le court-circuit entre spires statoriques et le défaut mixte stator/rotor. Deux méthodes sont utilisées pour la détection des défauts: la méthode classique à base de la transformée de Fourier et la méthode avancée à base de l’ondelette. L'étude est menée en fonctionnement de la machine en boucle fermée, où deux techniques de commande sans capteur de vitesse utilisant l'estimateur de type Luenberger sont considérées à savoir le contrôle direct du couple (DTC) et la commande par mode glissant (MG). Pour cela, divers tests de robustesse de la commande de la machine en défaut sont effectués à savoir les variations paramétriques et le fonctionnement à faible vitesse. Les résultats obtenus montrent clairement l'efficacité de cette technique dans la possibilité d'extraire les signatures du courant statorique pour détecter et localiser les défauts en régime stationnaire et non stationnaire

Caracterisation de la loi uniforme par les statistiques ordonnees

SIGLECNRS T Bordereau / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Imperialism in kipling's kim and forster's a passage to India

170 p. ; ill. ; 30 c