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Search results for: MOUNTAIN PASS THEOREM
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Speed Observer Structure of Induction Machine Based on Sliding Super-Twisting and Backstepping Techniques
PublicationThis paper presents an analysis of the two speed observer structures which are based on the backstepping and sliding super twisting approach. The observer stabilizing functions result from the Lyapunov theorem. To obtain the observer tuning gains the observer structure is linearized near the equilibrium point. The rotor angular speed is obtained from non-adaptive dependence. In the sensorless control system structure the classical...
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Equivalent Single Layer Models in Free Vibration Analysis of Laminated Multi-Layered Plates
PublicationThe performance of selected equivalent single-layer (ESL) models is evaluated within several classical benchmark tests for small amplitude free vibration analysis of multi-layered plates. The authors elaborated their own Finite Element software based on the first-order shear deformation (FOSD) theory with some modifications incorporated including a correction of the transverse shear stiffness and an application of zigzag type functions....
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Simulation of Signal Propagation Along Fractional-Order Transmission Lines
PublicationIn this paper, the simulation method of signal propagation along fractional-order (FO) transmission lines is presented. Initially, fractional calculus and the model of FO transmission line are introduced. Then, the algorithm allowing for simulation of the nonmonochromatic wave propagation along FO transmission lines is presented. It employs computations in the frequency domain, i.e., an analytical excitation is transformed to the...
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Asymmetric Renyi Problem and > PATRICIA Tries
PublicationIn 1960 R´enyi asked for the number of random queries necessary to recover a hidden bijective labeling of n distinct objects. In each query one selects a random subset of labels and asks, what is the set of objects that have theselabels? Weconsider here anasymmetric version of the problem in which in every query an object is chosenwith probability p > 1/2 and we ignore “inconclusive” queries. We study the number of queries needed...
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Symmetry-Breaking Bifurcation for Free Elastic Shell of Biological Cluster, Part 2
PublicationWe will be concerned with a two-dimensional mathematical model for a free elastic shell of biological cluster. The cluster boundary is connected with its kernel by elastic links. The inside part is filled with compressed gas or fluid. Equilibrium forms of the shell of biological cluster may be found as solutions of a certain nonlinear functional-differential equation with several physical parameters. For each multiparameter this...
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Stability by linear approximation for time scale dynamical systems
PublicationWe study systems on time scales that are generalizations of classical differential or difference equations and appear in numerical methods. In this paper we consider linear systems and their small nonlinear perturbations. In terms of time scales and of eigenvalues of matrices we formulate conditions, sufficient for stability by linear approximation. For non-periodic time scales we use techniques of central upper Lyapunov exponents...
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Estimation of blood pressure parameters using ex-Gaussian model
PublicationThe paper presents an example of model-based estimation of blood pressure parameters (onset, systolic and diastolic pressure) from continuous measurements. First, the signal was low pass filtered and its quality was estimated. Good quality periods were divided into beats using an electrocardiogram. Next, the beginning of each beat of the blood pressure signal was approximated basing on the function created from the sum of two independent...
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Ultrasound-assisted solvent extraction of porous membrane packed solid samples: A new approach for extraction of target analytes from solid samples
PublicationFor the first time, a porous membrane-based method is proposed for the extraction of target analytes directly from the solid samples. This method involves the packing of solid sample inside a porous polypropylene membrane sheet whose edges are heat-sealed to fabricate a bag. This bag is immersed in a suitable solvent and the analytes are extracted by the application of ultrasound energy. The various factors that affect the extraction...
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Symulacje numeryczne jako wsparcie badania właściwości barier ochronnych
PublicationArtykuł przedstawia możliwości wykorzystania symulacji numerycznych do badań efektywności urządzeń bezpieczeństwa ruchu drogowego w aspekcie sposobów ich konfgurowania. Obecnie w celu dopuszczenia do stosowania bariery ochronne muszą przejść specjalistyczne testy zderzeniowe. Ze względu na wysoki koszt tych badań coraz częściej producenci barier oraz inne podmioty odpowiadające za urządzenia bezpieczeństwa ruchu drogowego (brd)...
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Interpolator wykorzystujący filtr z maskowaniem charakterystyki częstotliwościowej
PublicationInterpolator o dużej krotności wymaga stosowania dolnoprzepustowych filtrów cyfrowych o bardzo wąskim paśmie przejściowym. Przekłada się to na dużą złożoność obliczeniową i problemy z projektowaniem filtrów interpolacyjnych. W pracy zaproponowano użycie metody FRM rozbijającej filtr o wąskim paśmie przejściowym na grupę filtrów o obniżonych wymaganiach, co zmniejsza liczbę niezerowych współczynników. W rezultacie użycie tego rozwiązania...
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Quantum-correlation breaking channels, broadcasting scenarios, and finite Markov chains
PublicationOne of the classical results concerning quantum channels is the characterization of entanglementbreakingchannels [M. Horodecki et al., Rev. Math. Phys 15, 629 (2003)]. We address the questionwhether there exists a similar characterization on the level of quantum correlations which may gobeyond entanglement. The answer is fully affirmative in the case of breaking quantum correlationsdown to the, so called, QC (Quantum-Classical)...
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Computational issues of solving the 1D steady gradually varied flow equation
PublicationIn this paper a problem of multiple solutions of steady gradually varied flow equation in the form of the ordinary differential energy equation is discussed from the viewpoint of its numerical solution. Using the Lipschitz theorem dealing with the uniqueness of solution of an initial value problem for the ordinary differential equation it was shown that the steady gradually varied flow equation can have more than one solution....
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Hybridization of the FDTD method with use of the discrete Green's function
PublicationIn this contribution, a hybrid technique is presented which combines the finite-difference time-domain (FDTD) method and the discrete Green's function (DGF) formulation of this method. FDTD is a powerful technique for the analysis of complex penetrable objects but its application is not efficient when the computational domain includes many free-space cells. Therefore, the hybrid method was developed which is applicable to complex...
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Constructive Controllability for Incompressible Vector Fields
PublicationWe give a constructive proof of a global controllability result for an autonomous system of ODEs guided by bounded locally Lipschitz and divergence free (i.e. incompressible) vector field, when the phase space is the whole Euclidean space and the vector field satisfies so-called vanishing mean drift condition. For the case when the ODE is defined over some smooth compact connected Riemannian manifold, we significantly strengthen...
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Non-Adaptive Speed and Position Estimation of Doubly-Fed Induction Generator in Grid-Connected Operations
PublicationThe nonadaptive speed and position estimation scheme for a doubly-fed induction generator (DFIG) is presented in this article. The observer structure is based on the extension of the mathematical model of DFIG to the introduced H vector. Based on the defined H vector, the nonadaptive position and speed estimation is proposed. The Lyapunov method is extended to the practical stability theorem to stabilize the structure. The classic...
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An application of acoustic sensors for the monitoring of road traffic
PublicationAssessment of road traffic parameters for the developed intelligent speed limit setting decision system constitutes the subject addressed in the paper. Current traffic conditions providing vital data source for the calculation of the locally fitted speed limits are assessed employing an economical embedded platform placed at the roadside. The use of the developed platform employing a low-powered processing unit with a set of microphones,...
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2015. Motion analysis of a kitesurfer employing a vision-based measurement system
PublicationAbstract. Kitesurfing is a relatively new phenomenon with rising popularity worldwide – a recently developed extreme watersport considered a high-risk injury sport. It combines elements of several other sports, in particular, sailing, surfing, windsurfing, wakeboarding, and snowboarding. The main purpose of authors’ research in the present paper is to use a vision-based system for measuring a kitesurfer’s body movements in order...
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Measurement method for capacitive sensors for microcontrollers based on a phase shifter
PublicationA complete measurement method dedicated to capacitive sensors has been developed. It includes the development of hardware (an analogue interface circuit for microcontrollers with built-in times/counters and analogue comparators) and software (a measurement procedure and a systematic error calibration (correction) algorithm which is based on a calibration dictionary). The interface circuit consists of a low-pass filter and a phase...
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Sea, River, Lake Ice Properties and Their Applications in Practices
PublicationThis Special Issue aims to highlight research articles focusing on the geographical scale of glacier and lake ice variations, as well as the engineering scale of ice properties and their practical applications via laboratory tests and numerical modeling. Additionally, it includes research on ecosystems under lake ice. The main goal is successfully achieved through the joint efforts of authors, anonymous reviewers, and editorial...
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Adaptive Method of Adjusting Flowgraph for Route Reconstruction in Video Surveillance Systems
PublicationPawlak’s flowgraph has been applied as a suitable data structure for description and anal- ysis of human behaviour in the area supervised with multicamera video surveillance system. Infor- mation contained in the flowgraph can be easily used to predict consecutive movements of a partic- ular object. Moreover, utilization of the flowgraph can support reconstructing object route from the past video images. However, such a flowgraph with...
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Technique to improve CMRR at high frequencies in CMOS OTA-C filters
PublicationIn this paper a technique to improve the common-mode rejection ratio (CMRR) at high frequencies in the OTA-C filters is proposed. The technique is applicable to most OTA-C filters using CMOS operational transconductance amplifiers (OTA) based on differential pairs. The presented analysis shows that a significant broadening of CMRR bandwidth can be achieved by using a differential pair with the bodies of transistors connected to...
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Matrix-based robust joint fingerprinting and decryption method for multicast distribution of multimedia
PublicationThis paper addresses the problem of unauthorized redistribution of multimedia content by malicious users (pirates). The solution proposed here is a new joint fingerprinting and decryption method which meets the requirements for both imperceptibility and robustness of fingerprints and scalability in terms of design and distribution of fingerprinted multimedia content. The proposed method uses a simple block cipher based on matrix...
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Employing a biofeedback method based on hemispheric synchronization in effective learning
PublicationIn this paper an approach to build a brain computer-based hemispheric synchronization system is presented. The concept utilizes the wireless EEG signal registration and acquisition as well as advanced pre-processing methods. The influence of various filtration techniques of EOG artifacts on brain state recognition is examined. The emphasis is put on brain state recognition using band pass filtration for separation of individual...
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The study of Arduino Uno feasibility for DAQ purposes
PublicationUsing microcontroller systems becomes a routine in various measurement and control tasks. Their wide availability together with a huge potential of extending their functionality by additional modules allows developing advanced measuring and monitoring systems by non-specialists. However, using popular example codes often leads the user to pass over or not to be aware of the limitations of the system and drawing too far-reaching...
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Application of the discrete Green's function-based antenna simulations for excitation of the total-field/scattered-field interface in the FDTD method
PublicationIn this article, the discrete Green's function formulation of the finite-difference time-domain (DGF-FDTD) method is proposed for simulation of wire antennas irradiating inhomogeneous dielectric scatterers. Surface equivalence theorem in the discrete domain is used to separate the problem into an inhomogeneous domain and a wire antenna that are simulated with the use of FDTD and DGF-FDTD, respectively. Then, the excitation of the...
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Hybrid Technique Combining the FDTD Method and Its Convolution Formulation Based on the Discrete Green's Function
PublicationIn this letter, a technique combining the finite-difference time-domain (FDTD) method and its formulation based on the discrete Green's function (DGF) is presented. The hybrid method is applicable to inhomogeneous dielectric structures that are mutually coupled with wire antennas. The method employs the surface equivalence theorem in the discrete domain to separate the problem into a dielectric domain simulated using the FDTD method...
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On the Limiting Distribution of Lempel-Ziv’78 Redundancy for Memoryless Sources
PublicationWe study the Lempel-Ziv'78 algorithm and show that its (normalized) redundancy rate tends to a Gaussian distribution for memoryless sources. We accomplish it by extending findings from our 1995 paper, in particular, by presenting a new simplified proof of the central limit theorem (CLT) for the number of phrases in the LZ'78 algorithm. We first analyze the asymptotic behavior of the total path length in the associated digital search...
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The saga of a fish: from a survival guide to closing lemmas
PublicationIn the paper by D. Burago, S. Ivanov and A. Novikov, “A survival guide for feeble fish”, it has been shown that a fish with limited velocity can reach any point in the (possibly unbounded) ocean provided that the fluid velocity field is incompressible, bounded and has vanishing mean drift. This result extends some known global controllability theorems though being substantially nonconstructive. We give a fish a different recipe...
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On a comparison principle and the uniqueness of spectral flow
PublicationThe spectral flow is a well-known quantity in spectral theory that measures the variation of spectra about 0 along paths of selfadjoint Fredholm operators. The aim of this work is twofold. Firstly, we consider homotopy invariance properties of the spectral flow and establish a simple formula which comprises its classical homotopy invariance and yields a comparison theorem for the spectral flow under compact perturbations. We apply...
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New Two-center Ellipsoidal Basis Function Neural Network for Fault Diagnosis of Analog Electronic Circuits
PublicationIn the paper a new fault diagnosis-oriented neural network and a diagnostic method for localization of parametric faults in Analog Electronic Circuits (AECs) with tolerances is presented. The method belongs to the class of dictionary Simulation Before Test (SBT) methods. It utilizes dictionary fault signatures as a family of identification curves dispersed around nominal positions by component tolerances of the Circuit Under Test...
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Experiment with small objects floating under water in the harbor security aspect.
PublicationObservation of the underwater area is the element of general trend which primary purpose is to protect and enhance the safety of the selected region. The aim of the paper is to present the acoustic characteristics of typical objects floating on the surface or under the water, which constitute some knowledge on how to detect these objects. Create a catalog of acoustic signatures and acoustic images of objects mostly floating under...
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Thermodynamic Cycle Concepts for High-Efficiency Power Plans. Part A: Public Power Plants 60+
PublicationAn analysis was carried out for different thermodynamic cycles of power plants with air turbines. Variants with regeneration and different cogeneration systems were considered. In the paper, we propose a new modification of a gas turbine cycle with the combustion chamber at the turbine outlet. A special air by-pass system of the combustor was applied and, in this way, the efficiency of the turbine cycle was increased by a few points....
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Highly linear CMOS triode transconductor for VHF applications
PublicationA high-speed, fully balanced complementary-symmetry metal-oxide-semiconductor (CMOS) triode transconductor is presented. The proposed approach exploits a pseudo-differential-pair triode configuration with a simple adaptive circuit stabilising the drain-to-source voltages of metal-oxide-semiconductor (MOS) transistors. Since no additional active circuits (apart from the resistors made of the cut-off MOS devices) and no feedback...
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Regularized Local Multivariate Reduced-Order Models With Nonaffine Parameter Dependence
PublicationThis paper addresses a singular problem, not yet discussed in the literature, which occurs when parametric reduced-order models are created using a subspace projection approach with multiple concatenated projection bases. We show that this technique may lead to the appearance of localized artifacts in the frequency characteristics of a system, even when the reduced-order projection basis is rich enough to describe the original...
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Speed observer of induction machine based on backstepping and sliding mode for low‐speed operation
PublicationThis paper presents a speed observer design based on backstepping and slidingmode approaches. The inputs to the observer are the stator current and thevoltage vector components. This observer structure is extended to the integra-tors. The observer stabilizing functions contain the appropriate sliding surfaceswhich result from the Lyapunov function. The rotor angular speed is obtainedfrom the non‐adaptive formula with a sliding...
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Justification of quasi-stationary approximation in models of gene expression of a self-regulating protein
PublicationWe analyse a model of Hes1 gene transcription and protein synthesis with a negative feedback loop. The effect of multiple binding sites in the Hes1 promoter as well as the dimer formation process are taken into account. We consider three, possibly different, time scales connected with: (i) the process of binding to/dissolving from a binding site, (ii) formation and dissociation of dimers, (iii) production and degradation of Hes1...
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Simulation of Wave Propagation in Media Described by Fractional-Order Models
PublicationIn this paper, algorithms for simulation of the wave propagation in electromagnetic media described by fractional-order (FO) models (FOMs) are presented. Initially, fractional calculus and FO Maxwell's equations are introduced. The problem of the wave propagation is formulated for media described by FOMs. Then, algorithms for simulation of the non-monochromatic wave propagation are presented which employ computations in the time...
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Mieszanie w klasie niejednorodnych łańcuchów Markowa i kwadratowych operatorów stochastycznych
PublicationRozprawa doktorska poświęcona jest zagadnieniu asymptotycznych własności w klasie nieskończenie wymiarowych niejednorodnych łańcuchów Markowa z czasem dyskretnym oraz w klasie kwadratowych operatorów stochastycznych. W pierwszej kolejności definiowane są różne rodzaje asymptotycznego zachowania (mieszania) niejednorodnych łańcuchów Markowa odpowiadające zbieżności w normowej i mocnej topologii operatorowej oraz omówione są relacje...
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Coplanar Waveguide-Fed Broadband Microwave Devices with (or without) a Thin Dielectric Substrate for Use in Flexible Electronic Systems
PublicationTwo examples of microwave devices, fed by a coplanar waveguide and realized on a thin substrate (or without such a substrate), are employed to investigate the influence of devices’ curvatures and the proximity of different materials on their parameters. To perform the tests, a broadband antenna and a low-pass filter are chosen. A feeding coplanar waveguide is realized on a dielectric material brick attached to an SMA connector...
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Municipal wastewater reclamation: Reclaimed water for hydrogen production by electrolysis – A case study
PublicationThis paper presents an analysis of a treatment system selection for municipal wastewater stream based on the DuPont Water Solutions WAVE software. The results obtained based on an analysis of 7 different processing cases studies (ultrafiltration and reverse osmosis) confirmed that the application of 2-pass membrane systems enables the reclamation of water from municipal wastewater that fulfills the requirements concerning the...
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Depth Images Filtering In Distributed Streaming
PublicationIn this paper, we propose a distributed system for point cloud processing and transferring them via computer network regarding to effectiveness-related requirements. We discuss the comparison of point cloud filters focusing on their usage for streaming optimization. For the filtering step of the stream pipeline processing we evaluate four filters: Voxel Grid, Radial Outliner Remover, Statistical Outlier Removal and Pass Through....
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DEPTH IMAGES FILTERING IN DISTRIBUTED STREAMING
PublicationIn this paper we discuss the comparison of point cloud filters focusing on their applicability for streaming optimization. For the filtering stage within a stream pipeline processing we evaluate three filters: Voxel Grid, Pass Through and Statistical Outlier Removal. For the filters we perform series of the tests aiming at evaluation of changes of point cloud size and transmitting frequency (various fps ratio). We propose a distributed...
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Sound quality metrics applied to road noise evaluation
PublicationRoad noise monitoring systems typically measure sound levels in specific time periods. The more insightful approach suggests to measure also the nature of noise. Sound quality of sounds such as car noise can be objectively evaluated by several parameters. One of them is psychoacoustic annoyance, described by loudness, tone color, and the temporal structure of sound. In this paper the assessment of several sound quality parameters, such...
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HOW EFFICIENT IS NOISE LABELING OF TIRES?
PublicationSince 2012 all new tires in Europe must be labeled. The label contains general information about tire performance concerning rolling resistance (that corresponds to fuel economy), noise emission and wet grip (only for passenger car tires). Measurements of noise performance of tires must be performed according to the Annex 3 of the Regulation No 117 of the Economic Commission for Europe of the United Nations. The regulation specifies...
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Multiple output differential OTA with linearizing bulk-driven active-error feedback loop for continuous-time filter applications
PublicationA CMOS circuit realization of a highly linear multiple-output differential operational transconductance amplifier (OTA) has been proposed. The presented approach exploits a differential pair as an input stage with both the gate and the bulk terminals as signal ports. For the proposed OTA, improved linearity is obtained by means of the active-error feedback loop operating at the bulk terminals of the input stage. SPICE simulations...
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Analysis of Roughness, the Material Removal Rate, and the Acoustic Emission Signal Obtained in Flat Grinding Processes
PublicationIn this work, the analysis of the acoustic emission (AE) signal in grinding processes is addressed. The proposed analysis method decomposes the acoustic signal into three frequency ranges. The total energy of each range is determined, as well as the highest frequency. Different grinding experiments were carried out, according to a full factorial design of experiments (DOE), in which feed speed, depth of cut, and transversal step...
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Light intensity analysis of photovoltaic parameters for perovskite solar cells
PublicationThe number of publications on perovskite solar cells (PSC) continues to grow exponentially. Although the efficiency of PSC is exceeded 25.5%, not every research laboratory can reproduce this result or even pass the border of 20%. Unfortunately, it is not always clear which dominating mechanism is responsible for the performance drop. Here, we develop a simple method of light intensity analysis of JV parameters allowing the understanding...
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Methodology for Performing Bathymetric Measurements of Shallow Waterbodies Using an UAV, and their Processing Based on the SVR Algorithm
PublicationState-of-art methods of bathymetric measurements for shallow waterbodies use Global Navigation Satellite System (GNSS) receiver, bathymetric Light Detection and Ranging (LiDAR) sensor or satellite imagery. Currently, photogrammetric methods with the application of Unmanned Aerial Vehicles (UAV) are gathering great importance. This publication aims to present step-by-step methodology for carrying out the bathymetric measurements...
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On weak solutions of the boundary value problem within linear dilatational strain gradient elasticity for polyhedral Lipschitz domains
PublicationWe provide the proof of an existence and uniqueness theorem for weak solutions of the equilibrium problem in linear dilatational strain gradient elasticity for bodies occupying, in the reference configuration, Lipschitz domains with edges. The considered elastic model belongs to the class of so-called incomplete strain gradient continua whose potential energy density depends quadratically on linear strains and on the gradient of...
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Non-Adaptive Rotor Speed Estimation of Induction Machine in an Adaptive Full-Order Observer
PublicationIn the sensorless control system of an induction machine, the rotor speed value is not measured but reconstructed by an observer structure. The rotor speed value can be reconstructed by the classical adaptive law with the integrator. The second approach, which is the main contribution of this paper, is the non-adaptive structure without an integrator. The proposed method of the rotor speed reconstruction is based on an algebraic...