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Littérature scientifique sur le sujet « SWITCHING WAVELET »

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Publié le 11 septembre 2023

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Articles de revues sur le sujet "SWITCHING WAVELET"

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Türkmenoğlu, Veli, Mustafa Aktaş, Serkan Karataş et Halil İbrahim Okumuş. « Soft Set-Based Switching Faults Decision Making in DTC Induction Motor Drives ». Journal of Circuits, Systems and Computers 24, no 02 (27 novembre 2014) : 1550021. http://dx.doi.org/10.1142/s0218126615500218.

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This paper introduces a method for detection and identification of IGBT-based drive open-circuit fault of DTC induction motor drives. The detection mechanism is based on soft set theory and wavelet decomposition, if it is detailed, ⊼-product decision making method and sym2 wavelet decomposition have been used in the detection mechanism. In this method, the stator currents have been used as an input to the system. The stator current has been used for the detection of the fault. The signal analysis has been performed up to the six level details wavelets decomposition. Faulty switch is detected by applying soft set theory to sixth level wavelets transformation. This is the first time applied to inverter in induction motor drives fault detection. The results demonstrate that the proposed fault detection and diagnosis system has very good capabilities.
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Guillén, Daniel, Gina Idárraga-Ospina et Camilo Cortes. « A New Adaptive Mother Wavelet for Electromagnetic Transient Analysis ». Journal of Electrical Engineering 67, no 1 (1 janvier 2016) : 48–55. http://dx.doi.org/10.1515/jee-2016-0007.

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Abstract Wavelet Transform (WT) is a powerful technique of signal processing, its applications in power systems have been increasing to evaluate power system conditions, such as faults, switching transients, power quality issues, among others. Electromagnetic transients in power systems are due to changes in the network configuration, producing non-periodic signals, which have to be identified to avoid power outages in normal operation or transient conditions. In this paper a methodology to develop a new adaptive mother wavelet for electromagnetic transient analysis is proposed. Classification is carried out with an innovative technique based on adaptive wavelets, where filter bank coefficients will be adapted until a discriminant criterion is optimized. Then, its corresponding filter coefficients will be used to get the new mother wavelet, named wavelet ET, which allowed to identify and to distinguish the high frequency information produced by different electromagnetic transients.
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CHEN, WENJIE, XU YANG et ZHAOAN WANG. « AN APPLICATION OF COMPLEX WAVELETS FOR HIGH FREQUENCY SWITCHING NOISE DETECTION ». Journal of Circuits, Systems and Computers 18, no 01 (février 2009) : 97–102. http://dx.doi.org/10.1142/s0218126609004958.

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Switching signal is always composed of a series of fast voltage and current transient impulsive waves, which are created during turn-on and turn-off operation of the switching elements. This paper presents a scalogram and phase spectrum analyzing approach for the high-frequency switching noise detection. A complex Gaussian wavelet is used to extract the oscillation feature of the noise signal. The proposed scheme is more suitable in discriminating the type of switching noise than conventional wavelet transform approaches. Simulation results show the effectiveness and advantages of the method.
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FUKUMA, S. « Switching Wavelet Transform for ROI Image Coding ». IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences E88-A, no 7 (1 juillet 2005) : 1995–2006. http://dx.doi.org/10.1093/ietfec/e88-a.7.1995.

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Alam, M. Shafiul, Md Shamimul Haque Chowdhury et Muhammad Athar Uddin. « Power System Switching Transient Detection using Wavelet Transformed Based Signal Decomposition ». IIUC Studies 7 (19 octobre 2012) : 241–48. http://dx.doi.org/10.3329/iiucs.v7i0.12270.

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Switching transient phenomena in Electric Power System develop several disturbances, sometimes very hazardous for the electrical equipment life, for the environment and for the human life. Switching transient phenomena produce over voltage, over current and electrical fields, which haven't to neglect. Several types of wavelet network algorithms have been considered for detection of power system switching transients. But both time and frequency information are accessible by multiresolution analysis (MRA). This paper presents a wavelet transform based multiresolution analysis of power system signal to detect, localize and extract switching transients. Power system switching transients have been simulated using MATLAB-7.01. The key idea underlying the approach is to decompose a distorted signal into other signals which represents a smoothed version and detailed version of the original signal. The decomposition is performed using multiresolution analysis. The proposed method appears to be robust for detection and localization of power quality disturbances produced due to load switching and capacitor switching. DOI: http://dx.doi.org/10.3329/iiucs.v7i0.12270 IIUC Studies Vol.7 2011: 241-248
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Gaeid, Khalaf S., Mshari Aead Asker, Nada N. Tawfeeq et Salam Razooky Mahdi. « Computer Simulation of PMSM Motor with Five Phase Inverter Control using Signal Processing Techniques ». International Journal of Electrical and Computer Engineering (IJECE) 8, no 5 (1 octobre 2018) : 3697. http://dx.doi.org/10.11591/ijece.v8i5.pp3697-3710.

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The signal processing techniques and computer simulation play an important role in the fault diagnosis and tolerance of all types of machines in the first step of design. Permanent magnet synchronous motor (PMSM) and five phase inverter with sine wave pulse width modulation (SPWM) strategy is developed. The PMSM speed is controlled by vector control. In this work, a fault tolerant control (FTC) system in the PMSM using wavelet switching is introduced. The feature extraction property of wavelet analysis used the error as obtained by the wavelet de-noised signal as input to the mechanism unit to decide the healthy system. The diagnosis algorithm, which depends on both wavelet and vector control to generate PWM as current based manage any parameter variation. An open-end phase PMSM has a larger range of speed regulation than normal PMSM. Simulation results confirm the validity and effectiveness of the switching strategy.
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Lin, Chih-Min, Kun-Neng Hung et Chun-Fei Hsu. « Adaptive Neuro-Wavelet Control for Switching Power Supplies ». IEEE Transactions on Power Electronics 22, no 1 (janvier 2007) : 87–95. http://dx.doi.org/10.1109/tpel.2006.886630.

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Li, Hao, Meng Zhao, Hao Yan et Xingwu Yang. « Nanoseconds Switching Time Monitoring of Insulated Gate Bipolar Transistor Module by Under-Sampling Reconstruction of High-Speed Switching Transitions Signal ». Electronics 8, no 10 (22 octobre 2019) : 1203. http://dx.doi.org/10.3390/electronics8101203.

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An insulated gate bipolar transistor (IGBT) is one of the most reliable critical components in power electronics systems (PESs). The switching time during IGBT turn-on/off transitions is a good health status indicator for IGBT. However, online monitoring of IGBT switching time is still difficult in practice due to the requirement of extremely high sampling rate for nanoseconds time resolution. The compressed sensing (CS) method shows a potential to overcome the technical difficult by reducing the sampling rate. To further improve the efficiency and reduce the computational time for IGBT online condition monitoring (CM), an under-sampling reconstruction method of an IGBT high-speed switching signal is presented in this paper. First, the physical mechanism and signal characteristics of IGBT switching transitions are analyzed. Then, by utilizing the sparse characteristics of IGBT switching signal in the wavelet domain, the wavelet basis is used for sparse representation. The stagewise orthogonal matching pursuit (StOMP) algorithm is proposed to enhance the convergence speed for switching signal reconstruction. Experiments are performed on not only a double-pulse test rig but also a real Pulse-Width Modulation (PWM) converter. Results show that the IGBT high-speed switching transitions signal can be accurately recovered with a reduced sampling rate and the nanoseconds switching time change can be monitored for IGBT CM.
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Ketabi, A., M. Khoshkholgh et R. Feuillet. « A New Approach to Nonsinusoidal Steady-State Power System Analysis ». Mathematical Problems in Engineering 2009 (2009) : 1–18. http://dx.doi.org/10.1155/2009/584637.

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A new analysis method using wavelet domain for steady-state operating condition of power system is developed and introduced. Based on wavelet-Galerkin theory, the system components such as resistor, inductor, capacitor, transmission lines, and switching devices are modeled in discrete wavelet domain for the purpose of steady-state analysis. To solve system equations, they are transferred to wavelet domain by forming algebraic matrix-vector relations using the wavelet transform coefficients and the equivalent circuit is thus built for system simulation. After describing the new algorithm, two-case studies are presented and compared with the simulations in the time domain to verify the accuracy and computational performance.
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Patcharoen, Theerasak, Suntiti Yoomak, Atthapol Ngaopitakkul et Chaichan Pothisarn. « Simulation study and experimental results for detection and classification of the transient capacitor inrush current using discrete wavelet transform and artificial intelligence ». Open Physics 16, no 1 (18 avril 2018) : 93–104. http://dx.doi.org/10.1515/phys-2018-0016.

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Abstract This paper describes the combination of discrete wavelet transforms (DWT) and artificial intelligence (AI), which are efficient techniques to identify the type of inrush current, analyze the origin and possible cause on the capacitor bank switching. The experiment setup used to verify the proposed techniques can be detected and classified the transient inrush current from normal capacitor rated current. The discrete wavelet transforms are used to detect and classify the inrush current. Then, output from wavelet is acted as input of fuzzy inference system for discriminating the type of switching transient inrush current. The proposed technique shows enhanced performance with a discrimination accuracy of 90.57%. Both simulation study and experimental results are quite satisfactory with providing the high accuracy and reliability which can be developed and implemented into a numerical overcurrent (50/51) and unbalanced current (60C) protection relay for an application of shunt capacitor bank protection in the future.
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Thèses sur le sujet "SWITCHING WAVELET"

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Gu, Ye. « Wavelet-based adaptive video coding for packet-switching networks ». Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/37021.

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Xie, Yingfu. « Maximum likelihood estimation and forecasting for GARCH, Markov switching, and locally stationary wavelet processes / ». Umeå : Dept. of Forest Economics, Swedish University of Agricultural Sciences, 2007. http://epsilon.slu.se/2007107.pdf.

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Zhao, Yi. « Studies on error control of 3-D zerotree wavelet video streaming ». Connect to resource, 2005. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1124811298.

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Thesis (Ph. D.)--Ohio State University, 2005.
Title from first page of PDF file. Document formatted into pages; contains xix, 136 p.; also includes graphics (some col.). Includes bibliographical references (p. 129-136). Available online via OhioLINK's ETD Center
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4

Yao, Hong Mei. « Wavelet based dynamic modelling of simulated moving bed chromatographic processes ». Thesis, Curtin University, 2009. http://hdl.handle.net/20.500.11937/1918.

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Simulated moving bed chromatography process (SMBCP) is the technical realisation of a countercurrent adsorption process through the cyclic port switching. SMB technology reduces the cost of packing material with high loading capacity and provides high purity and high recovery in a very short time. Major commodity applications have been found in the petroleum, food, biotechnology, pharmaceutical and fine chemical industries. The industrial applications bring an emergent demand to improve the SMBCP operation for higher product quality, productivity, efficiency and robustness. However, for this particular process, we encounter several challenges. Firstly, the interplay of the effects of strong nonlinearities, competition of solutes, mass transfer resistance and fluid dynamic dispersion produces steep concentration fronts. Mathematical model accounted for this particular property constitutes a serious difficulty for the solution procedure. Secondly, a dynamic SMB model consists of a set of partial differential, ordinary differential and algebraic equations, which are highly coupled. The large size is a problem due to its intensive computation when on-line optimisation and real-time control are necessary. Thirdly, the SMB unit operation exhibits complex dynamics. Process metrics for design and operation can be determined only when a cyclic steady state is reached after a certain number of switching. Achieving this steady state by solving the PDE models cycle after cycle involves expensive calculation. Studies have been carried out to solve these problems through process analysis, investigation on spatial discretisation techniques, and development of an accelerated integration scheme.Through a systematic study on the advances of SMB modelling, design and control, a set of functionally equivalent models for SMBCP are identified and summarized for their practical applications. The limitations of the existing modelling techniques in industrial applications are also identified. Furthermore, structural analysis of the existing models is conducted for a better understanding of the functionality and suitability of each model. Suggestions are given on how to choose an appropriate model with sufficient accuracy while keeping the computational demand reasonably low for real time control.Effort is made on to the systematic investigation of different numerical methods for the solution of PDEs to circumvent the steep gradients encountered in chromatographic separation. Comprehensive studies are conducted on a single column chromatographic process represented by a transport-dispersive-equilibrium linear model. Numerical solutions from the upwind-1 finite difference, wavelet-collocation, and high resolution methods are evaluated by quantitative comparisons with the analytical solution for a range of Peclet numbers. It reveals that for a PDE system with a low Peclet number, all existing numerical methods work well, but the upwind finite difference method consumes the most time for the same degree of accuracy of the numerical solution. The high resolution method provides an accurate numerical solution for a PDE system with a medium Peclet number. The wavelet collocation method is capable of catching up steep changes in the solution, and thus can be used for solving PDE models with high singularity.The advantages and disadvantages of the wavelet based approaches are further investigated through several case studies on real SMBCP system. A glucose-fructose separation process is firstly chosen with its relatively simple isotherm representations. Simulations are conducted using both wavelet collocation and upwind finite difference methods. For more complicated applications, an enantiomers separation process is selected. As the PDEs model exhibit a certain degree of singularity, wavelet collocation and high resolution methods are adopted for spatial discretisation. It is revealed that both the wavelet based approaches and high resolution methods are good candidates in terms of computation demand and prediction accuracy on the steep front. This is the first time that these two frontier numerical methods are used for such a complex SMB system models and our results are encouraging for the development of model-based online control scheme.In developing a new scheme to rapidly obtain the solution at steady state for any arbitrary initial condition, the concept of Quasi-Envelope (QE) is adopted under the consideration that a SMBCP can be treated as a pseudo-oscillatory process because of a large number of continuous switching. The scheme allows larger steps to be taken to predict the slow change of starting state within each switching. Combined with previously developed wavelet-based technique, this method is successfully applied to the simulation of a SMB sugar separation process. Investigations are also carried out on the location of proper starting point for the algorithm and on the effect of changing stepsize to the convergence of iteration method. It is found that if the starting state of Quasi-Envelope is chosen to be the same as the original function, the multivalue algorithm would require similar computational effort to achieve the steady state prediction, regardless of the integration stepsize. If using constant stepsize, launching QE later is helpful when quasi-envelope displays steep change at the start-up period. A changing stepsize produces slow convergence compared to the constant stepsize strategy, thus increasing the work load where the stepsize change is occurring. Other iteration method is required to be imposed to achieve faster convergence right from the beginning. Potential applications can be seen for other chemical engineering processes with inherent cyclic behaviour.
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5

Yao, Hong Mei. « Wavelet based dynamic modelling of simulated moving bed chromatographic processes ». Curtin University of Technology, Department of Chemical Engineering, 2009. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=128426.

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Simulated moving bed chromatography process (SMBCP) is the technical realisation of a countercurrent adsorption process through the cyclic port switching. SMB technology reduces the cost of packing material with high loading capacity and provides high purity and high recovery in a very short time. Major commodity applications have been found in the petroleum, food, biotechnology, pharmaceutical and fine chemical industries. The industrial applications bring an emergent demand to improve the SMBCP operation for higher product quality, productivity, efficiency and robustness. However, for this particular process, we encounter several challenges. Firstly, the interplay of the effects of strong nonlinearities, competition of solutes, mass transfer resistance and fluid dynamic dispersion produces steep concentration fronts. Mathematical model accounted for this particular property constitutes a serious difficulty for the solution procedure. Secondly, a dynamic SMB model consists of a set of partial differential, ordinary differential and algebraic equations, which are highly coupled. The large size is a problem due to its intensive computation when on-line optimisation and real-time control are necessary. Thirdly, the SMB unit operation exhibits complex dynamics. Process metrics for design and operation can be determined only when a cyclic steady state is reached after a certain number of switching. Achieving this steady state by solving the PDE models cycle after cycle involves expensive calculation. Studies have been carried out to solve these problems through process analysis, investigation on spatial discretisation techniques, and development of an accelerated integration scheme.
Through a systematic study on the advances of SMB modelling, design and control, a set of functionally equivalent models for SMBCP are identified and summarized for their practical applications. The limitations of the existing modelling techniques in industrial applications are also identified. Furthermore, structural analysis of the existing models is conducted for a better understanding of the functionality and suitability of each model. Suggestions are given on how to choose an appropriate model with sufficient accuracy while keeping the computational demand reasonably low for real time control.
Effort is made on to the systematic investigation of different numerical methods for the solution of PDEs to circumvent the steep gradients encountered in chromatographic separation. Comprehensive studies are conducted on a single column chromatographic process represented by a transport-dispersive-equilibrium linear model. Numerical solutions from the upwind-1 finite difference, wavelet-collocation, and high resolution methods are evaluated by quantitative comparisons with the analytical solution for a range of Peclet numbers. It reveals that for a PDE system with a low Peclet number, all existing numerical methods work well, but the upwind finite difference method consumes the most time for the same degree of accuracy of the numerical solution. The high resolution method provides an accurate numerical solution for a PDE system with a medium Peclet number. The wavelet collocation method is capable of catching up steep changes in the solution, and thus can be used for solving PDE models with high singularity.
The advantages and disadvantages of the wavelet based approaches are further investigated through several case studies on real SMBCP system. A glucose-fructose separation process is firstly chosen with its relatively simple isotherm representations. Simulations are conducted using both wavelet collocation and upwind finite difference methods. For more complicated applications, an enantiomers separation process is selected. As the PDEs model exhibit a certain degree of singularity, wavelet collocation and high resolution methods are adopted for spatial discretisation. It is revealed that both the wavelet based approaches and high resolution methods are good candidates in terms of computation demand and prediction accuracy on the steep front. This is the first time that these two frontier numerical methods are used for such a complex SMB system models and our results are encouraging for the development of model-based online control scheme.
In developing a new scheme to rapidly obtain the solution at steady state for any arbitrary initial condition, the concept of Quasi-Envelope (QE) is adopted under the consideration that a SMBCP can be treated as a pseudo-oscillatory process because of a large number of continuous switching. The scheme allows larger steps to be taken to predict the slow change of starting state within each switching. Combined with previously developed wavelet-based technique, this method is successfully applied to the simulation of a SMB sugar separation process. Investigations are also carried out on the location of proper starting point for the algorithm and on the effect of changing stepsize to the convergence of iteration method. It is found that if the starting state of Quasi-Envelope is chosen to be the same as the original function, the multivalue algorithm would require similar computational effort to achieve the steady state prediction, regardless of the integration stepsize. If using constant stepsize, launching QE later is helpful when quasi-envelope displays steep change at the start-up period. A changing stepsize produces slow convergence compared to the constant stepsize strategy, thus increasing the work load where the stepsize change is occurring. Other iteration method is required to be imposed to achieve faster convergence right from the beginning. Potential applications can be seen for other chemical engineering processes with inherent cyclic behaviour.
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6

Lin, Shih-Shan, et 林詩珊. « VIX Volatility Wavelet-CEV Model-----Using Regime Switching and Wavelet Analysis ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/98824892123640019643.

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碩士
國立交通大學
財務金融研究所
93
The purpose of this research is to model the volatility index, VIX, formulated by CBOE using the concept of Regime Switching and piecewise linear structure. I adopt the Wavelet analysis to inspect the properties of CEV parameters in the stochastic volatility model. Generally speaking, volatility is relatively high in the bear market and low in the bull market. The converging rate on average is higher in the bull market than that in the bear market. Wavelet analysis which can deal with the unusual structure change in the market enables the parameter estimation to be correctly specified.
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7

YADAV, ANKIT. « DESIGN OF SWITCHING SCHEMES FOR VOLTAGE SOURCE INVERTER ». Thesis, 2016. http://dspace.dtu.ac.in:8080/jspui/handle/repository/14992.

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DC-AC Inverters are key components in various industrial applications that include power supplies, motor drive systems and power systems. Now-a-days dc-ac inverters (both 1- phase & 3-phase) are finding more attention in renewable energy systems also. These inverters are big source of harmonics, which leads to various other problems like heating of instruments, faulty operation of protection devices etc. The harmonics generated by inverter can be controlled and minimise by controlling the switching of the device. Several approaches has been made already to deal with this problem like as carrier based PWM (pulse width modulation), selected harmonic elimination, Random PWM etc. Although the methods named above have been succeeded in improving the quality of power by reducing the harmonics but the problem is still not solved completely, so it still required attention. The Proposed project work is to design new switching schemes for single phase H-bridge Voltage Source DC – AC inverter. The motive of new switching technique is to further improve the quality of output by reducing total harmonic distortion. Two switching scheme are proposed for the project work. One is ―modified hysteresis switching scheme‖ and another one is ―wavelet modulation techniques‖. Both schemes are considered for voltage source inverter. Modified hysteresis switching scheme as well as wavelet based modulation technique would be studied, analysed and applied for switching of single phase and three phase voltage source inverters to produce significantly improved fundamental components and low harmonic contents. The inverter along with its switching technique would be simulated using MATLAB software and results would be analysed.
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8

Wang, Cheng-Wei, et 王政偉. « Identification of Power Switching Using Wavelet Transform and Neural Network ». Thesis, 2003. http://ndltd.ncl.edu.tw/handle/2683hc.

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碩士
中原大學
電機工程研究所
91
Recently, power quality is becoming an increasingly important topic due to the high technology industry and precision instruments developed rapidly. The poor power quality will make the serious loss of the manufactory and sometimes will damage the equipments. Hence, improvement of power quality is an important task for utility companies and their customers. Power system transients caused by switching is one of the important problem of power quality. Hence, it is worth to understand the property of transients and the influence upon power system. This thesis focuses on the transients, which are caused by the load breaker switching and the capacitor bank switching. Several kinds of transients disturbance signals, such as load breaker switching on/off, capacitor bank switching on/off, the different phase angles of voltages while the switch actions, and the position of the switch, are simulated by the power system software EDSA. This thesis identifies these transient disturbance signals, by the other two analysis tools, which are the wavelet transform and the SOM network. This thesis studies two different power systems, which were simulated by EDSA, and finds the wavelet coefficients for identification. The study results show that the proposed method is applicable.
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Chen, Po-Yuan, et 陳柏元. « Application of Wavelet Transform and Artificial Intelligencefor Identifying Locations of Switching Capacitor Transients ». Thesis, 2005. http://ndltd.ncl.edu.tw/handle/22258706215959711491.

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碩士
中原大學
電機工程研究所
93
In recent years, due to the rapid developments of the hi-tech industry as well as much more usages of the precise production equipments and test instruments, the far high power quality (PQ) is demanded nowadays. Hence, improvement of power quality is an important task for utility companies and their customers. Generally, power quality problems include voltage swell, voltage sag, power harmonic, three-phase imbalance, frequency variation and voltage flicker. Besides, the electromagnetic transient phenomenon of the power system, such as capacitor switching, can cause incident of the voltage and current transients that would result in over voltage transient due to the resonance phenomenon. The high voltage and current transient may result in damage of devices in the power systems and malfunction of protection equipment of sensitive loads. Therefore, capacitor switching transient is a serious threat to power electronic equipments in the viewpoint of PQ. Actually, the accurate location and time of PQ problem are useful for responsibility authority and accident correction Therefore, identifying and locating the locations of transient sources have attracted more attention of utility engineers and scholars. This thesis presents a new method for efficiently locating the sources associated for utility capacitor switching transients. The proposed method first combines wavelet transform and Parserval theorem to extract the features of the transients. Then proper location number for metering measurements by fuzzy clustering is determined. Finally, the features and transient source location is trained by neural networks. Diverse patterns of PQ events are simulated by Matlab6.5/NeuroSolutions software Finally, an 18-bus power system is used for testing, Simulation results obtained by using Matlab6.5/NeuroSolutions show that the proposed approach is effective and relatively accurate in comparison with existing approaches.
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Yun, Yang Ting, et 楊婷勻. « Application of Wavelet Transform to the Intermittent Switching Characteristics of Gap Flow between Two Bluff Bodies Arranged Side by Side ». Thesis, 2004. http://ndltd.ncl.edu.tw/handle/17365600826166661334.

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碩士
國立中興大學
土木工程學系
92
The flow characteristics of gap-flow downstream of two side-by-side bluff bodies are provided with temporal variation of unstable phenomenon in the uniform fluid field. The distinct identities of vortex shedding obtained by the single point measurement method and the analysis of Fast Fourier Transform (FFT) are insufficient. The primary objective of the present study is to develop a unique measurement technique that combines the use of two one-component fiber laser Doppler velocimetries (FLDV) and particle image velocimetry (PIV), aiming to perform simultaneous velocity measurement to integrate both time and flow domains of the switching gap flow and the wide and narrow wakes corresponding to these two stationary cylinders including square, circular, and flat forms. Moreover, by using the Wavelet transform (WT), the energy-history of each component shedding frequency can be described as time-frequency domain. First, this study aims to validate the feasibility of Wavelet transform which is then applied to the analysis of velocity time signal obtained by FLDV. Meanwhile, the temporal variation of the full-field velocity maps in the flow domain of interest can be obtained by employing PIV. To synchronize the PIV and two FLDV data during measurement, the two FLDV velocity signals and PIV camera triggering signal were transferred into the data acquisition board in the same time, so the corresponding time (or phase) of each PIV velocity map can be precisely determined. Therefore, the instantaneous frequency of the wide and narrow wakes (analyzed by wavelet transform) as well as the corresponding instantaneous full-field velocity map (including the deflected gap flow) can be identified. Based upon the experimental results, it is found that the switching characteristics of gap-flow patterns can be classified into three categories. These categories are defined as : (1) gap-flow switching from one side to the other side instantaneously; (2) gap-flow switching spontaneously from one side to the center direction, in which the gap flow was oriented parallel to the free-stream flow for short duration, and then biasing to original side; (3) gap-flow switching spontaneously from one side to the other, and in the intermediate time where existing another short duration stable flow pattern (which can be termed an intermediate flow pattern). Furthermore, the correlation between two temporal frequency of wide and narrow wakes were studied completely. As we known, Fast Fourier transform (FFT) and wavelet transform which provided with the time-mean and instantaneous frequency contents respectively, and the spectrum analysis results of them were compared in detail.
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Livres sur le sujet "SWITCHING WAVELET"

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Glabisz, Wojciech. Pakietowa analiza falkowa w zagadnieniach mechaniki. Wrocław : Oficyna Wydawnicza Politechniki Wrocławskiej, 2004.

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Chapitres de livres sur le sujet "SWITCHING WAVELET"

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Liò, Pietro, Anna T. Lawniczak, Shengkun Xie et Jiaying Xu. « Wavelet-Domain Statistics of Packet Switching Networks Near Traffic Congestion ». Dans Bio-Inspired Computing and Communication, 268–79. Berlin, Heidelberg : Springer Berlin Heidelberg, 2008. http://dx.doi.org/10.1007/978-3-540-92191-2_24.

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Penm, Jack, et R. D. Terrell. « Sparse-Patterned Wavelet Neural Networks and Their Applications to Stock Market Forecasting ». Dans Nonlinear Financial Econometrics : Markov Switching Models, Persistence and Nonlinear Cointegration, 161–70. London : Palgrave Macmillan UK, 2011. http://dx.doi.org/10.1057/9780230295216_8.

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Jammazi, Rania. « Oil Shock Transmission to Stock Market Returns : Wavelet-Multivariate Markov Switching GARCH Approach ». Dans The Interrelationship Between Financial and Energy Markets, 71–111. Berlin, Heidelberg : Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-55382-0_4.

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Dghais, Amel Abdoullah, et Mohd Tahir Ismail. « Modeling Relationship Between Stock Market of UK and MENA Countries : A Wavelet Transform and Markov Switching Vector Error Correction Model Approach ». Dans Proceedings of the International Conference on Computing, Mathematics and Statistics (iCMS 2015), 165–73. Singapore : Springer Singapore, 2016. http://dx.doi.org/10.1007/978-981-10-2772-7_17.

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« Dynamic Chaos Spectrum of Chaotic Switching Converters I : Wavelet Method ». Dans Chaos Analysis and Chaotic EMI Suppression of DC-DC Converters, 141–71. Singapore : John Wiley & Sons Singapore Pte. Ltd, 2014. http://dx.doi.org/10.1002/9781118451106.ch8.

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K., Uvanesh, Suraj Kumar Nayak, Biswajeet Champaty, Goutam Thakur, Biswajit Mohapatra, D. N. Tibarewala et Kunal Pal. « Development of a Surface EMG-Based Control System for Controlling Assistive Devices ». Dans Robotic Systems, 765–85. IGI Global, 2020. http://dx.doi.org/10.4018/978-1-7998-1754-3.ch040.

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The current study discusses about the development of an EMG based wireless control system for the patients suffering from high-level motor disability. Surface EMG (sEMG) signals were processed in the time domain and using discrete wavelet transforms (DWT). The statistical features of the signals (sEMG, envelope of the squared sEMG and wavelet processed sEMG) were determined and analyzed. The analysis of the features suggested that the features of the envelope of the squared sEMG signals were sufficient to be used for high-efficiency classification and control signal generation. A hall-effect sensor based switching mechanism was introduced for controlling the duration of the activation of the device. The control signals were wirelessly transmitted to the assistive device (robotic vehicle). The training and the subsequent use of the developed control system were easy.
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Khan, Laiq, et Rabiah Badar. « Hybrid Adaptive NeuroFuzzy Bspline Based SSSC Damping Control Paradigm ». Dans Handbook of Research on Novel Soft Computing Intelligent Algorithms, 787–828. IGI Global, 2014. http://dx.doi.org/10.4018/978-1-4666-4450-2.ch026.

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This work explores the potential of Bspline based Adaptive NeuroFuzzy Wavelet control to damp low frequency power system oscillations using Static Synchronous Series Compensator (SSSC). A comparison of direct and indirect adaptive control based on Hybrid Adaptive Bspline Wavelet Control (ABSWC) is presented by introducing the online identification block. ABSWC with Identification (ABSWCI) provides the sensitivity information of the plant to control system. The parameters of the control and identification block are updated online using gradient descent based back propagation algorithm. The robustness of the proposed control algorithm has been evaluated for local and inter-area modes of oscillations using different faults. The nonlinear time domain simulation results have been analyzed on the basis of different performance indices and time-frequency representation showing that ABSWC effectively damps low frequency oscillations and incorporation of online identification optimizes the control system performance in terms of control effort which reduces the switching losses of the converter.
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Botsford, Louis W., J. Wilson White et Alan Hastings. « Age-structured models : Short-term transient dynamics ». Dans Population Dynamics for Conservation, 87–121. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198758365.003.0004.

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Linear age-structured models eventually grow geometrically, and reach a stable age distribution (as in Chapter 3). This chapter describes what happens before “eventually.” That is, it describes the short-term, “transient” dynamics that occur when a population is perturbed, then begins to return to its stable distribution. Transients involve eigenvalues other than the largest (real) one, so the chapter begins by showing how complex eigenvalues can produce population cycles. It then addresses factors that make transients shorter or longer. In some cases, frequent environmental disturbances may prevent populations from ever reaching equilibrium. That scenario can be described by switching from linear models to linearized models varying about an equilibrium. The chapter describes temporal characteristics of that variability (such as time scales and frequencies), which require new tools: Fourier transforms and wavelets. These reveal how age-structured populations are more sensitive to certain environmental frequencies than to others, a phenomenon termed cohort resonance.
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Actes de conférences sur le sujet "SWITCHING WAVELET"

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Ibrahim, Atubga David Atia, Bonny Ernestina Linda et Wang Zinan. « SNR Enhancement by Discrete Wavelet Transform filtering on Φ-OTDR sensing for vibration detection ». Dans Photonics in Switching and Computing. Washington, D.C. : OSA, 2020. http://dx.doi.org/10.1364/psc.2020.jtu3f.5.

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Tan, Rodney H. G., et V. K. Ramachandaramurthy. « Capacitor bank switching classification using scale selection continuous wavelet transform ». Dans 2009 International Conference on Power Electronics and Drive Systems (PEDS 2009). IEEE, 2009. http://dx.doi.org/10.1109/peds.2009.5385785.

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Berman, Kevin, Aharon Z. Karon, Alessio Medda et Krishan K. Ahuja. « Detection of Screech Mode-Switching Using the Discrete Wavelet Transform ». Dans 2018 AIAA/CEAS Aeroacoustics Conference. Reston, Virginia : American Institute of Aeronautics and Astronautics, 2018. http://dx.doi.org/10.2514/6.2018-3464.

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Dong, Huajun, Hongyan Wang et Jijun Shen. « Study of wavelet denoising in images of vacuum switching arc ». Dans 2012 International Conference on Computer Science and Information Processing (CSIP). IEEE, 2012. http://dx.doi.org/10.1109/csip.2012.6308785.

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Xiaoming Liu, Xiangning Liu, Chunguang Hou, Xue Leng et Zenghui Lai. « Arc fault diagnosis and analysis based on wavelet neural network ». Dans 2011 1st International Conference on Electric Power Equipment - Switching Technology (ICEPE-ST). IEEE, 2011. http://dx.doi.org/10.1109/icepe-st.2011.6122965.

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Zhou, Dengdeng, Zhigang Liu, Weili Bai, Jian Xie et Hua Yang. « A Line Selection Method Based on Capacitor Switching by Complex Wavelet ». Dans 2009 Asia-Pacific Power and Energy Engineering Conference. IEEE, 2009. http://dx.doi.org/10.1109/appeec.2009.4918051.

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Kun-Neng Hung, Chih-Min Lin et Fu-Shan Ding. « Adaptive Neural Control for Switching Power Supplies Using Gaussian Wavelet Networks ». Dans The 2006 IEEE International Joint Conference on Neural Network Proceedings. IEEE, 2006. http://dx.doi.org/10.1109/ijcnn.2006.247182.

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Guojiang, Zhang, Shi Mingming, Zhang Chenyu, Sha Haoyuan et She Changjia. « Harmonic Impedance Detection Based on Capacitor Switching and Wavelet Packet Analysis ». Dans 2019 IEEE 9th Annual International Conference on CYBER Technology in Automation, Control, and Intelligent Systems (CYBER). IEEE, 2019. http://dx.doi.org/10.1109/cyber46603.2019.9066771.

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Li Ling-ling, Jun-Hao Li, Peng-Ju He et Cheng-Shang Wang. « The use of wavelet theory and ARMA model in wind speed prediction ». Dans 2011 1st International Conference on Electric Power Equipment - Switching Technology (ICEPE-ST). IEEE, 2011. http://dx.doi.org/10.1109/icepe-st.2011.6123016.

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Novakov, Stevan, Chung-Horng Lung, Ioannis Lambadaris et Nabil Seddigh. « Studies in applying PCA and wavelet algorithms for network traffic anomaly detection ». Dans 2013 IEEE 14th International Conference on High Performance Switching and Routing (HPSR). IEEE, 2013. http://dx.doi.org/10.1109/hpsr.2013.6602310.

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