On the online classification of data streams using weak estimators

In this paper, we propose a novel online classifier for complex data streams which are generated from non-stationary stochastic properties. Instead of using a single training model and counters to keep important data statistics, the introduced online classifier scheme provides a real-time self-adjusting learning model. The learning model utilizes the multiplication-based update algorithm of the Stochastic Learning Weak Estimator (SLWE) at each time instant as a new labeled instance arrives. In this way, the data statistics are updated every time a new element is inserted, without requiring that we have to rebuild its model when changes occur in the data distributions. Finally, and most importantly, the model operates with the understanding that the correct classes of previously-classified patterns become available at a later juncture subsequent to some time instances, thus requiring us to update the training set and the training model. The results obtained from rigorous empirical analysis on multinomial distributions, is remarkable. Indeed, it demonstrates the applicability of our method on synthetic datasets, and proves the advantages of the introduced scheme

First report of naturally infected Sergentomyia minuta with Leishmania major in Tunisia

International audienceBackground: Many sand fly species are implicated in the transmission cycle of Leishmania parasites around the world. Incriminating new sand flies species, as vectors of Leishmania is crucial to understanding the parasite-vector transmission cycle in different areas in Tunisia and surrounding countries. Findings: Seventy-four unfed females belonging to the genera Sergentomyia and Phlebotomus were collected in South Tunisia between June and November 2014, using sticky papers. PCR-RFLP (Restriction Fragment Length Polymorphism) analysis of the internal transcribed spacer 1 (ITS1) was used for Leishmania parasites detection and identification. Leishmania (L.) major (Yakimoff & Shokkor, 1914) was identified within two Sergentomyia (S.) minuta (Rondani, 1843) and one Phlebotomus papatasi (Scopoli, 1786). Conclusion: This is the first report of L. major identified from S. minuta in Tunisia. This novel finding enhances the understanding of the transmission cycle of L. major parasites of cutaneous leishmaniasis in an endemic area in South Tunisia

A fixed point theorem for a Meir-Keeler type contraction through rational expression

In this paper, we establish a new fixed point theorem for a Meir-Keeler type contraction through rational expression. The presented theorem is an extension of the result of Dass and Gupta (1975). Some applications to contractions of integral type are given

Localization of solutions for nonlinear elliptic problems with critical growth

We study the existence and the multiplicity of solutions for the problem -div(p(x)del u) =u(2*-1) +lambda u, u > 0 in Omega and u = 0 on partial derivative Omega, when the set of the minimizers for the weight p has multiple connected component. We study also the case where this set has one connected component and has complex topology

Double-fed three-phase induction machine abc model for simulation and control purposes

The aim of this paper is to develop a doubly-fed induction machine (DFIM) abc model suitable for the simulation of this machine in any system with control circuits and/or connections to thegrid by means of power electronics converters. The circuit-oriented approach has been chosen in order to represent the DFIM model as a rotating transformer. In fact, a class of universalmachine model has been built to be used with simple input electrical parameters such as stator and rotor resistances, self, leakage and mutual inductances. With the available model, it ispossible to simulate any kind of asymmetry in both stator and rotor sides with or without variations of the machine parameters. A specific wound-rotor induction machine model, using only resistances, inductances and controlled voltage sources, has been developed. The couplingeffects between stator and rotor has been taken into account usingan approach to represent stator-rotor mutual inductance. The performances of the model have been verified bycomparison between simulation and experimental results on a 0.09kW-220V/380V-50Hz-4 poles DFIM working in motoring mode at standstill, no-load and rated load conditions

Improvement of Frequency Resolution for Three-phase Induction Machine Fault Diagnosis

This paper deals with the use of the zoom FFT algorithm (ZFFTA) for the electrical fault diag-nosis of squirrel-cage three-phase induction machines with a special interest in broken rotor bar situation. The motor current can be analysed to observe the side bands harmonics around the fundamental frequency. In this case, it is necessary to take a very long data sequence to get high frequency resolution. This is not always possible due to the hardware and software limitations. The proposed algorithm can be considered for solving high frequency resolution problem with-out increasing the initial data acquisition size. The ZFFTA is applied to detect incipient rotor fault in a three-phase squirrel-cage induction machine operating at two speeds with pole number change by using both stator current and stray flux sensor

A Web-Based Remote Laboratory for Monitoring and Diagnosis of AC Electrical Machines

This paper deals with the development of a virtual platform for a Web-based remote application dedicated to condition monitoring and fault detection for ac electrical machines. The platform is based on several tools developed by using the LabVIEW software. Various techniques of condition monitoring and diagnosis of electrical and mechanical faults in ac electrical machines have been integrated such as the broken rotor bar, winding short circuit, bearing damage, or static/dynamic eccentricities. The main features are related to a user-friendly interface, a low-maintenance source code, and a standardized database for ac electrical machine diagnosis. The platform architecture, as well as three different test-rig configurations, has been described. The complete system can be controlled in both local and remote modes by using a simple Internet connection. Some remote experiences have been carried out between the University of Picardie \u201cJules Verne,\u201d Amiens, France, and the University of Bologna, Bologna, Italy, to verify the effectiveness of the proposed system. The direct applications of this original package are based on diagnosis techniques applied to ac electrical machine faults. Some examples of rotor broken bar detection using classical techniques have been presented to show the effectiveness of the proposed platform. Further information will soon be available on the Open European Laboratory on Electrical Machines Web site: www.oelem.org

Simulation of a Doubly-Fed Induction Machine for Wind Turbine Generator Fault Analysis

For modern large wind farms, it is more and more interesting to design an efficient diagnostics system oriented to wind turbine generators based on doubly-fed induction machine (DFIM). In this paper, a complete system will be analyzed by suitable simulations to deeply study fault influence and to identify the best diagnostic procedure to perform predictive maintenance. All the research efforts have been developed on different signature analysis (XSA) in order to detect or to predict electrical and mechanical faults in wound-rotor induction machines. They will be applied on wind turbine generators and their effectiveness will be studied