This paper introduces a systematic approach to synthesize linear parameter-varying (LPV) representations of nonlinear (NL) systems which are originally defined by control affine state-space representations. The conver...
This paper introduces a systematic approach to synthesize linear parameter-varying (LPV) representations of nonlinear (NL) systems which are originally defined by control affine state-space representations. The conversion approach results in LPV state-space representations in the observable canonical form. Based on the relative degree concept of NL systems, the states of a given NL representation are transformed to new coordinates that provide its normal form. In the SISO case, all nonlinearities of the original system are embedded in one NL function which is factorized to construct the LPV form. An algorithms is proposed for this purpose. The resulting transformation yields an LPV model where the scheduling parameter depends on the derivatives of the inputs and outputs of the system. In addition, if the states of the NL model can be measured or estimated, then the procedure can be modified to provide LPV models scheduled by these states. Examples are included for illustration.
Subject matter of this paper deals with issues of the environmental impact of infrasound noise associated with operation of low-power wind turbines. It is now the current and relevant problem for both the cognitive an...
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Subject matter of this paper deals with issues of the environmental impact of infrasound noise associated with operation of low-power wind turbines. It is now the current and relevant problem for both the cognitive and utilitarian standpoint. There is now a considerable growth in the number of such installations in Poland, Europe and in the world, due to the possibility of locating them on existing building roofs in heavily urbanized areas, and without having to build additional supporting structures. As part of the study, measurements of low frequency acoustic signals generated during operation of micro turbine equipped with a rotor of vertical axis of rotation relative to the wind direction have been performed. Analyses were carried out in order to determine the impact of wind speed and selected meteorological parameters on the level of infrasound signals emitted by the test turbine. In addition, frequency analysis of the recorded signals was performed. Then, the obtained results were subjected to comparative analysis. In summary, the achieved results were referred to the limits of sound pressure intensity level of infrasound signals as specified for the working environment in accordance with the Polish Standard PN-Z-01338.
Subject matter of this paper applies to improvement of acoustic emission method used in the diagnosis of on load tap changers of high power transformers. During measurement of acoustic emission signals generated by da...
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Subject matter of this paper applies to improvement of acoustic emission method used in the diagnosis of on load tap changers of high power transformers. During measurement of acoustic emission signals generated by damages or defects, which can appear in insulation system and in the power transformer tap changers, various forms of noise signals may occur. Interferences occurring during measurements under laboratory and under industrial conditions can be generated either by sources placed inside the studied electric power device or they can be emitted in their immediate vicinity. Sources of interfering signals are physical phenomena of a mechanical, electrical or acoustical nature. Interferences appearing during measurement of acoustic emission pulses generated by electrical discharges and other types of defects that overlap the measured waveforms may result in their distortion. As part of the research conducted, the results of which are presented in this paper, following was subjected under consideration: measurements of acoustic noise signals generated by partial surface discharges occurring on support and bushing insulators were performed.
The nonlinear nature of bioprocesses often leads to the occurrence of the self-sustained oscillations of the biomass concentration in continuous flow bioreactors. For some practical reasons, sometimes it is necessary ...
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The subject matter of this article concerns the diagnostic test results of transformer cores by measuring and analysing vibroacoustic signals registered during their normal operation. The main objective of this resear...
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The subject matter of this article concerns the diagnostic test results of transformer cores by measuring and analysing vibroacoustic signals registered during their normal operation. The main objective of this research study conducted by the authors, the results of which are published in this paper, is a critical analysis of vibroacoustic criteria, which are adopted in Poland nowadays, and based on which, the assessment of the core technical condition is performed. This article presents exemplary results that were obtained on two twin units of type TET 8509 with a power of 40 MVA. The paper species diagnosed structures, the measurement system applied, and the currently used methodology to assess the degree of core loosening. To determine the efficacy and assessment accuracy of the applied vibroacoustic criteria, correlation between mechanical vibration measurements of the tested transformer tanks and results obtained by gas chromatography was performed.
Subject of the paper concerns determination of the feasibility and indication of the application scope of optical spectroscopy methods in the diagnosis of high-voltage insulators. Results of measurements of optical ra...
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Subject of the paper concerns determination of the feasibility and indication of the application scope of optical spectroscopy methods in the diagnosis of high-voltage insulators. Results of measurements of optical radiation emitted by partial and complete electrical discharges occurring on a support insulator model placed in air are presented in the paper. Registration was performed using a spectrophotometer, enabling for measurement of optical radiation in the range from 200 to 1800 nm. The primary objective of the laboratory tests was to evaluate the impact of supply voltage changes in the range from 0 to 60 kV on the intensity and spectral character of the optical radiation emitted by electric discharges generated on the porcelain insulation surface of the support insulator. In the scope of studies analyzes of the eects of voltage changes on the obtained spectral wave forms were performed, whereby voltage increase and reduction was examined separately. Additionally, measurements and analyzes carried out included impact estimation of the time period as the voltage was applied to the high-voltage electrodes on the course of optical phenomena related to the generation of electrical discharges.
This paper proposes a new Matlab toolbox to simplify the task of designing robustified Model Predictive controllers under both unstructured and structured uncertainties. With a user-friendly design, the toolbox offers...
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In this paper using results taken directly from linear matrix algebra we shall present a survey of the new results on controllability for linear both continuous-time and discrete-time switched dynamical systems with u...
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In this paper using results taken directly from linear matrix algebra we shall present a survey of the new results on controllability for linear both continuous-time and discrete-time switched dynamical systems with unconstrained admissible controls. controllability problems for different types of dynamical systems require the application of numerous mathematical concepts and methods taken directly from differential geometry, functional analysis, topology, matrix analysis and theory of ordinary and partial differential equations and theory of difference equations. In the paper we will use mainly statespace models of dynamical systems, which provide a robust and universal method for studying controllability of various classes of systems.
Articolul descrie modul în care metoda "connection pooling" optimizeazǍ accesul la baza de date. Pentru a demonstra faptul cǍ metoda într-adevǍr optimizeazǍ modul în care cerint〉ele sunt p...
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Articolul descrie modul în care metoda "connection pooling" optimizeazǍ accesul la baza de date. Pentru a demonstra faptul cǍ metoda într-adevǍr optimizeazǍ modul în care cerint〉ele sunt prelucrate, vom realiza un experiment care va cont〉ine douǍ scenarii, unul în care se foloseşte "connection pooling" şi un altul în care nu se foloseşte. La finalul experimentului, valorile obt〉inute vor demonstra cǍ accesul la baza de date este îmbunǍtǍt〉it *** studiu de caz este prezentat intr-o aplicatie cu scop medical. This paper describes how connection pooling optimizes database access. In order to prove that connection pooling really optimizes how requests are handled, we will make an experiment with two scenarios, one with connection pooling and one without this method. At the end, the values obtained will show that database access is greatly increased. A case study is presented for a medical specific application.
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