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Search results for: SYNTHETIC VARIABLES
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VARIABLE KINEMATICS OF HONING PROCESS – INFLUENCE ON MACHINED WORKPIECE
PublicationSurface quality of holes plays an important role in machine manufacturing industry especially in the production of car engines and hydraulic cylinders. Investigations of honing process were carried out by 6 years on horizontal CNC Sunnen’s honing machine HTH 4000S, on vertical conventional honing machine WMW’s SZS 200 and on CNC milling machine of Haas VF 3SS with equipment of Honingtec for honing. Measurements of cylindricity...
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Variable Speed AC Drives with Inverter Output Filters
PublicationThe advance of variable speed drives systems (VSDs) engineering highlights the need of specific technical guidance provision by electrical machines and drives manufacturers, so that such applications can be properly designed to present advantages in terms of both energy efficiency and expenditure. This book presents problems and solutions related to inverter-fed electrical motors. Practically orientated, the book describes the...
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Modeling variable curvature on the turnout diverging track length
PublicationThe paper presents three variants of variable curvature application on the entire length of the turnout diverging track. One linear and two nonlinear curvature cases: described the function of C1 and C0 class were considered. It turned out that both linear curve and the function of C1 class requires a significant (even twice) length of diverging track extending with respect to the base turnout. The curvature described by the function...
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Electric shock hazard in circuits with variable-speed drives
PublicationThe conventional approach to electrical safety under fault condition in typical power systems considers earth fault currents of sinusoidal waveform and frequency of 50/60 Hz. However, in circuits with variable-speed drives, there is earth fault current flow with harmonics, and these harmonics influence the threshold of ventricular fibrillation. The paper presents earth fault current waveforms in circuits with variable-speed drives...
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Shaping of the turnout diverging track with variable curvature sections
PublicationThe paper presents an analytical method of shaping the turnout diverging railroad track with variable curvature segments on its length, which in an evident way distinguished it from a typical solution, made up of a single circular arc with no transition curves. Two separate causes including a linear and a nonlinear curvature one in the form of a polynomial have been examined. The obtained solutions of the problem have a universal...
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Local hidden–variable models for entangled quantum states
PublicationWhile entanglement and violation of Bell inequalities were initially thought to be equivalent quantum phenomena, we now have different examples of entangled states whose correlations can be described by local hidden-variable models and, therefore, do not violate any of the Bell inequalities. We provide an up-to-date overview of the existing literature regarding local hidden-variable models for entangled quantum states, in both...
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Do Existential Variables Mediate Between Religious-Spiritual Facets of Functionality and Psychological Wellbeing
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Approximate solutions of mixed problems for first order partial differential equations with deviated variables.
PublicationPraca traktuje o przybliżaniu rozwiązań klasycznych równańróżniczkowo-funkcyjnych cząstkowych pierwszego rzędu rozwiązaniamiukładów quasiliniowych równań różnicowych. Nowe podejście dorozwiązywania równań nieliniowych zawdzięczamy metodziequasilinearyzacji dla zagadnień początkowo - brzegowych z odchylonymargumentem. Dla przyrostów pochodnych funkcji danej zakładamy nieliniowe oszacowanie typu Perrona. Załączone są wyniki eksperymentów...
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Evaluation of selected diagnostic variables for the purpose of assessing the ageing effects in high-power IGBTs
PublicationPrzedstawiono metodę wyznaczania dwóch wskaźników diagnostycznych, które mogą być używane do oceny zużycia modułów IGBT dużej mocy. Proponowane podejście jest próbą zaadaptowania znanej z literatury metody laboratoryjnej do pracy bezpośrednio w układzie napędowym pojazdu trakcyjnego. Rozważane wskaźniki diagnostyczne to rezystancja cieplna między półprzewodnikiem a podstawą modułu oraz napięcie nasycenia kolektor-emiter IGBT....
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Comparison of two methods for parameters selection of the proportional observer of induction motor state variables
PublicationArtykuł opisuje problemy odtwarzania prędkości obrotowej wału maszyny indukcyjnej przy wykorzystaniu estymatorów MRAS. Porównano dwie metody doboru wzmocnień obserwatora, analityczną i bazującą na algorytmach genetycznych
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Dynamic response of the PEM fuel cell to variable load conditions
PublicationOpisano układ zasilania oparty na 2 ogniwach paliwowych typu PEM o mocy 1.2 kW każde. Omówiono problem ograniczenie ogniwa paliwowego przez drugą zasadę termodynamiki. Przedstawiono charakterystyki układu w zależności od sygnału obciążenia typu: skok jednostkowy, półsinusoidalny, trójkątny, prostokątny i trapezowy.
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Thermal and Strength Properties of Lightweight Concretes with Variable Porosity Structures
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Attempt to operationalization of the category “involvement of employess”: model, type, variable
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Variable-structure algorithm for identification of quasi-periodically varying systems
PublicationThe paper presents a variable-structure version of a generalized notchfiltering (GANF) algorithm. Generalized notch filters are used for identification of quasi-periodically varying dynamic systems and can be considered an extension, to the system case, of classical adaptive notch filters. The proposed algorithm is a cascade of two GANF filters: a multiple-frequency "precise" filter bank, used for precise system tracking, and a...
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The experimental research on RC columns, loaded at sign-variable eccentricity
PublicationThe research focuses on testing the behaviour of the reinforced concrete columns compressed at a variable eccentricity. The fact of possible variable eccentricity in compressed columns is not considered in the current calculation procedures. The objective of the research was to examine whether indeed the load history has no impact and whether the reinforced concrete columns compressed at eccentric of variable sign could be analysed...
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On Sample Rate Conversion Based on Variable Fractional Delay Filters
PublicationThe sample rate conversion algorithm based on variable fractional delay filters is often used if the resampling ratio cannot be expressed as the ratio of small integer numbers or if it is not constant. The main advantage of such solution is that it allows for arbitrary resampling ratios which can even be changed during the resampling process. In this paper a discussion on influence of different approaches to fractional filter...
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Variable Fractional Delay Filter Design Using a Symmetric Window
PublicationIn this paper a numerically efficient method for designing a nearly optimal variable fractional delay (VFD) filter based on a simple and well-known window method is presented. In the proposed method a single window extracted from the optimal filter with fixed fractional delay (FD) is divided into even and odd part. Subsequently, the odd part is discarded and symmetric even part of the extracted window is used to design a family...
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Design of three control algorithms for an averaging tank with variable filing
PublicationAn averaging tank with variable filling is a nonlinear multidimensional system and can thus be considered a complex control sys-tem. General control objectives of such object include ensuring stability, zero steady state error and achieving simultaneously shortest possible settling time and minimal overshoot. The main purpose of this research work was the modelling and synthesis of three control systems for an averaging tank. In...
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Two-Stage Variable-Fidelity Modeling of Antennas with Domain Confinement
PublicationSurrogate modeling has become the method of choice in solving an increasing number of antenna design tasks, especially those involving expensive full-wave electromagnetic (EM) simulations. Notwithstanding, the curse of dimensionality considerably affects conventional metamodeling methods, and their capability to efficiently handle nonlinear antenna characteristics over broad ranges of the system parameters is limited. Performance-driven...
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Reliable Microwave Modeling By Means of Variable-Fidelity Response Features
PublicationIn this work, methodologies for low-cost and reliable microwave modeling are presented using variable-fidelity response features. The two key components of our approach are: (i) a realization of the modeling process at the level of suitably selected feature points of the responses (e.g., S-parameters vs. frequency) of the structure at hand, and (ii) the exploitation of variable-fidelity EM simulation data, also for the response...
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PROBABILISTIC ANALYSIS OF A SPACE TRUSS BY MEANS OF A MULTIDIMENSIONAL VARIABLE DESCRIPTION
PublicationThe objective of this paper is to present a variant of the point estimate method (PEM) to determine mean values and standard deviations of limit loads of engineering structures. This approach is illustrated by limit state analysis of a space truss, considering geometric and material imperfections. The calculations were performed for different random models, so the influence of random parameters on the limit load of the truss can...
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Optimum shape of turnout diverging track with segments of variable curvature
PublicationIn the paper an attempt has been made to focus on shaping the variable curvature in the diverging track of the railway turnout. Basing on some earlier studies, solutions provided with a circular arc in the mid-zone, and in the extreme regions with segments of non-linear curvature of equal length and zero curvature at the start and end of the turnout, have been assumed as models. The most advantageous type of curvature has been...
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A Family of Pb-based Superconductors with Variable Cubic to Hexagonal Packing
PublicationWe describe three previously unreported superconductors, BaPb3, Ba0.89Sr0.11Pb3, and Ba0.5Sr0.5Pb3. These three materials, together with SrPb3, form a distinctive isoelectronic family of intermetallic superconductors based on the stacking of Pb planes, with crystal structures that display a hexagonal to cubic perovskite-like progression, as rarely seen in metals. The superconducting transition temperatures (Tc) are similar for...
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Variable length sliding models for banking clients face biometry
PublicationAn experiment was organized in 100 bank branches to acquire biometric samples from nearly 5000 clients including face images. A procedure for creating face verification models based on continuously expanding database of biometric samples is proposed, implemented, and tested. The presented model applies to circumstances where it is possible to collect and to take into account new biometric samples after each positive verification...
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Variable-fidelity shape optimization of dual-rotor wind turbines
PublicationPurpose Dual-rotor wind turbines (DRWTs) are a novel type of wind turbines that can capture more power than their single-rotor counterparts. Because their surrounding flow fields are complex, evaluating a DRWT design requires accurate predictive simulations, which incur high computational costs. Currently, there does not exist a design optimization framework for DRWTs. Since the design optimization of DRWTs requires numerous model...
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Mixed systems with minimal and maximal lifetime variances
PublicationRozważa się mieszane układy złożone ze stałej liczby składników, których czasy zycia są niezależnymi zmiennymi losowymi o jednakowym rozkładzie i dodatniej wariancji. Bada się minimalną i maksymalną wariancję czasu życia rozważanych układów.
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Set membership estimation of parameters and variables in dynamic networks by recursive algorithms with moving measurment window
PublicationW artykule rozważana jest łączna estymacja przedziałowa zmiennych i parametrów w złożonej sieci dynamicznej w oparciu niepewne modele parametryczne i ograniczoną liczbę pomiarów. Opracowany został rekursywny algorytm estymacji z przesuwnym oknem pomiarowym, odpowiedni dla monitorowania sieci on-line. Okno pomiarowe pozwala na stabilizowanie klasycznego algorytmu rekurencyjnego estymacji i znacznie poprawienie obcisłości estymat....
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Hydrological Excitations of Polar Motion Derived from Different Variables of Fgoals − g2 Climate Model
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Distribution of invasive Cylindrospermopsis raciborskii in the East-Central Europe is driven by climatic and local environmental variables
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PLS-Based and Regularization-Based Methods for the Selection of Relevant Variables in Non-targeted Metabolomics Data
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A Comparison of Basic Training Variables in the Standard and Cambered Bar Bench Press Performed to Volitional Exhaustion
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Genetic and lifestyle variables associated with homocysteine concentrations and the distribution of folate derivatives in healthy premenopausal women
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Energy conversion in small water plants with variable speed PM generator
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Small Hydropower Plant With Integrated Turbine-Generators Working at Variable Speed
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Method of determining the degree of liquid aeration in a variable capacity displacement pump
PublicationThe Author concludes, that there is a possibility of determining a concrete value of the liquid aeration coefficient during the pump operation by finding such value of coefficient with which the increase of torque of mechanical losses is proportional to the indicated torque determined with a fixed value of increase of pressure in the pump working chambers. The fixed value of increase of pressure assumed in searching the liquid...
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Vibration Surveillance System with Variable Stiffness Holder for Milling Flexible Details
PublicationEfficient milling of the flexible details (i.e. rotor blades, thin-walled elements) using slender ball-end tools is a difficult task due to possibility of vibration occurrence. Because of the existence of certain conditions (small depths of cutting, regeneration phenomena), cutting process may lose stability and self-excited chatter vibration may appear. Frequency of the chatter vibration is close to dominant natural frequency...
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Variable Ratio Sample Rate Conversion Based on Fractional Delay Filter
PublicationIn this paper a sample rate conversion algorithm which allows for continuously changing resampling ratio has been presented. The proposed implementation is based on a variable fractional delay filter which is implemented by means of a Farrow structure. Coefficients of this structure are computed on the basis of fractional delay filters which are designed using the offset window method. The proposed approach allows us to freely...
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Innovative optimization algorithm of variable speed pumps in district heating systems.
PublicationW referacie przedstawiono innowacyjny algorytm matematyczny optymalizacji pracy pomp zmienno prędkościowych w systemach ciepłowniczych. Algorytm wykorzystuje procedurę iterecyjnego wyznaczania parametrów pracy pomp, których charakterystyki są linearyzowane odcinkami w układzie dwóch współrzędnych. Do rozwiązania modelu całkowitoliczbowego zaproponowano wykorzystanie systemu GAMS. W pracy przedstawiono podstawy metodologiczne i...
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Performance-Driven Inverse/Forward Modeling of Antennas in Variable-Thickness Domains
PublicationDesign of contemporary antenna systems is a challenging endeavor. The difficulties are partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities, but also constraints imposed upon the physical size of the radiators. Furthermore, conducting the design process at the level of full-wave electromagnetic (EM) simulations, otherwise dictated by reliability,...
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Neural Approximators for Variable-Order Fractional Calculus Operators (VO-FC)
PublicationThe paper presents research on the approximation of variable-order fractional operators by recurrent neural networks. The research focuses on two basic variable-order fractional operators, i.e., integrator and differentiator. The study includes variations of the order of each fractional operator. The recurrent neural network architecture based on GRU (Gated Recurrent Unit) cells functioned as a neural approximation for selected...
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Optimal segmented dampers configuration for a laminar body carrying variable payload
PublicationPublikacja prezentuje zagadnienia analizy doboru tłumienia i konfiguracji elementów tłumiących dla ciała płaskiego poddanego dwóm stanom obciążenia. W pracy zaakceptowano użycie elementów tłumiących o tłumieniu wiskotycznym i o współczynniku tłumienie zależnym od położenia tłoka tego elementu. Ponieważ różne aspekty komfortu prowadzą do przeciwnych wytycznych odnośnie wyboru własności tłumiących, rozwiązanie dobory parametrów tłumienia...
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Fatigue behaviour of SLM maraging steel under variable-amplitude loading
PublicationOne of the most challenging issues for additive manufactured materials is fatigue endurance. Engineering components often operate under complex, variable amplitude loadings, in which existing technological imperfections promote fatigue cracks growth and damage of elements eventually. In this study the effects of different variable-amplitude strain levels on fatigue life, 18Ni300 steel was tested. The work presents various behaviours...
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Experimental investigations of natural convection from circular plates at variable inclination
PublicationW pracy przedstawiono wyniki badań eksperymentalnych oraz bezwymiarową korelację liczb kryterialnych dla konwekcyjnej wymiany ciepła od izotermicznej płyty kołowej skierowanej ku górze dla różnych kątów pochylenia (od poziomej do pionowej) w szerokim zakresie wartości liczb Rayleigha. Badania przeprowadzono w wodzie dla płyty kołowej o średnicy 0,07 m. Celem pracy było określenie wpływu kąta pochylenia płyty na wartość liczby Nusselta.
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Time variable gain for long range sonar with chirp sounding signal
PublicationThe main purpose of applaying Time Variable Gain (TVG) in active sonars with digital signal processing is to reduce dynamic range of echo signal and adapt it to the dynamic range of the analogue to digital conversion. With high transmission losses level, the dynamic range of the input signal in long range sonars can be very high and even exceed 200dB. When chirp sounding signals with matched filtration are used, sonars can raech...
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Comments on “Closed Form Variable Fractional Time Delay Using FFT”
PublicationIn this letter drawbacks of the aforementioned paper are pointed out. The proposed approach is improved with minor modifications of the discrete frequency response. This allows for design of fractional delay filters which are close to optimal and can be efficiently implemented in the frequency domain using the sliding DFT based structure. Alternatively, the derived equivalent closed form formulae for offset windows can be used...
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Guided waves for monitoring of plate structures with linear cracks of variable length
PublicationDamage occurring at the work of plate structures may grow to a considerable size. The joint action – the detection of a defect at the earliest possible stage, the monitoring of its growth and the determination of its critical size in the context of structural reliability allows optimizing the cost of the maintenance and repair of structural elements. Thus the development of monitoring systems for permanent observation of fault...
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Proportional-derivative and Model-based Controllers for Control of a Variable Mass Manipulator
PublicationW artykule prezentowano wyniki analiza numeryczna dynamiki manipulatora o zmiennej masie. W skład manipulatora wchodzą jedynie członu i przeguby obrotowe. Ładowność chwytaka jest traktowana jako jedyny element o zmiennej masie. Podobnie jak w przypadku innych manipulatorów wyposażonych w przeguby obrotowe, parametry jego dynamika zależą od aktualnego ustawienia. Gdy przemieszczenia obejmują większy zakres roboczy, w równaniach...
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Multiobjective Aerodynamic Optimization by Variable-Fidelity Models and Response Surface Surrogates
PublicationA computationally efficient procedure for multiobjective design optimization with variable-fidelity models and response surface surrogates is presented. The proposed approach uses the multiobjective evolutionary algorithm that works with a fast surrogate model, obtained with kriging interpolation of the low-fidelity model data enhanced by space-mapping correction exploiting a few high-fidelity training points. The initial Pareto...
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Constant vs. Variable Efficiency of Electric Drive in Train Run Simulations
PublicationTrain run simulations, which focus on various power- and energy-oriented aspects, should reflect the losses in the electric powertrain. In general, the powertrain efficiency varies with respect to load and speed. Including this relation in simulation requires knowledge about detailed drivetrain parameters, which are often unavailable. This paper verifies the possibility to approximate the drivetrain efficiency in train run simulations...
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Proportional-Derivative and Model-Based Controllers for Control of a Variable Mass Manipulator
PublicationIn the paper, numerical analysis of dynamics of a variable mass manipulator is presented. A revolute joints composed manipulator is considered. Payload of the gripper is considered as the only element characterized by unknown value of its mass (variable between subsequent operations). As in other cases of the revolute joints composed manipulators, its behaviour dependents significantly on the pose of the manipulator. When the manipulator...