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Search results for: linear phase filters
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Open-Phase Fault Detection Method for Sensorless Five-Phase Induction Motor Drives with an Inverter Output Filter
PublicationThe paper presents the sensorless five-phase induction motor drive implementation with an inverter output filter with third harmonic injection. For the sensorless operation, the required observers are presented for the first and third harmonics with consideration of the inverter output filter. Moreover, the interaction of the observers and the control system is capable to handle a deactivation of one or two phases, which improves...
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Precise Point Positioning Method Based on Wide-lane and Narrow-lane Phase Observations and Between Satellites Single Differencing
PublicationThe issue of using PPP method in position determination was formed in 1997. In most developed methods, ionospheric-free linear combination is used in order to eliminate the impact of the ionospheric delay. However, this approach does not provide the directly determination of the total value of the ambiguities, and the ambiguities for the individual signals. Therefore, in many publications methods of avoiding these deficiencies...
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Influence of the air phase on water flow in dikes
PublicationNumerical models are often used to describe flow and deformation processes occurring in dikes during flood events. Modeling of such phenomena is a challenging task, due to the complexity of the system, consisting of three material phases: soil skeleton, pore water and pore air. Additional difficulties are transient loading caused by variable in time water levels, heterogeneity of the soil or air...
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Enhanced Mobility and Large Linear Nonsaturating Magnetoresistance in the Magnetically Ordered States of TmNiC2
PublicationWe have studied the magnetic, magnetotransport, and galvanomagnetic properties of TmNiC2. We find that the antiferromagnetic and field induced metamagnetic and ferromagnetic orderings do not suppress the charge density wave. The persistence of Fermi surface pockets, open as a result of imperfect nesting accompanying the Peierls transition, results in an electronic carriers mobility of the order of 4 × 103 cm2 V−1 s−1 in ferromagnetic...
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Comparison of the fracture toughness of pine wood determined on the basis of orthogonal linear cutting and frame sawing
PublicationIn this paper, the values of the fracture toughness of Scots pine determined by cutting tests are presented. The cutting tests were carried out using the samples of Scotch pine (Pinus sylvestris L.) from Pomeranian Region, Poland. These experiments were carried out on two research stands: orthogonal linear cutting tests were conducted using the microtome instrument and the frame saw PRW-15M was used for sawing tests. The values...
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Principles and Developments of Solid-Phase Microextraction
PublicationSample preparation has been commonly considered a critical step of the analytical process. In this sense, remarkable efforts have been made to develop efficient sample preparation techniques which could overcome the limitations of conventional approaches. Since its inception in the early 1990’s, solid-phase microextraction (SPME) has become a widespread miniaturized sample preparation technique for extraction and preconcentration...
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Ionic thermoelectric effect in Cu2-δSe during phase transition
PublicationThe ionic Seebeck coefficient was studied in copper selenide with Cu1.99Se, Cu1.95Se and Cu1.8Se stoichiometry which was synthesized with a melt crystallization method. To measure the ionic Seebeck coefficient of copper ions, 0.15C6H12N4CH3I + 0.85CuI solid-state electrolyte was prepared. Electrolyte layers were pressed with copper selenide powder into a sandwich-like structure. At the temperature of 410 K, the materials have ionic...
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Current trends in solid-phase microextraction (SPME) fibre catings
PublicationThis critical review presents information on known and innovative approaches to the manufacture of fibre coatings used in solid-phase microextraction (SPME). The properties, advantages and drawbacks of the different types of commercially available SPME fibre coatings are discussed in detail, as are those of novel types of coatings and the methodologies of their preparation. The applications of fibre coatings in the solid-phase...
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Power flow in typical series-parallel hybrid filters topologies
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Compensation of Dead Time Effects for Shunt Active Power Filters
PublicationThe paper presents a comprehensive approach to the compensation of the grid current distortion for shunt active power filter systems. Four different sources of current distortion are addressed: imperfect grid synchronization caused by the distortion in the grid voltages, time delays in the estimation of compensating currents and grid voltages, fluctuations of the dc bus voltage, and the distortion of inverter output voltages due...
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Development of HFB with the Use of 2nd Order Pass-Band Filters
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Efficient tolerance analysis of continuous-time Gm-C filters
PublicationW pracy przedstawiono efektywną metodą analizy tolerancji dowolnych filtrów Gm-C. Przedstawiono ogólny model filtrów Gm-C oraz jego opis algebraiczny. Używając tego podejścia, wyprowadzono formuły pozwalające na wyznaczenie odchyłek funkcji przenoszenia filtru spowodowanych odchyłkami wartości elementów filtru od wartości nominalnych. Proponowana metoda charakteryzuje się niewielką złożonością obliczeniową, co pozwala na jej wykorzystanie...
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Gradient-based optimization of filters using FD-TD software
PublicationW artykule opisane jest nowe podejście do zagadnienia optymalizacji filtrów mikrofalowych pasmowo-przepustowych. Optymalizacja prowadzona jest z wykorzystaniem metody gradientowej poszukiwania minimum wartości funkcji celu oraz przy założeniu pełnofalowej symulacji obwodów metodą różnic skończonych w dziedzinie czasu. W artykule pokazane jest, że stosując zaawansowane techniki cyfrowego przetwarzania sygnałów możliwa jest optymalizacja...
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New approach to computer aided design of coupled resonator filters
PublicationW niniejszej pracy zastosowane zostały gradientowa metoda optymalizacji oraz nowa definicja funkcji celu do projektowania filtrów mikrofalowych. Definicja funkcji celu została oparta na badaniu położenia zer i biegunów funkcji przenoszenia optymazlizownanych układów.
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Canonic structures of old order elliptic Gm-C filters.
PublicationW pracy zaproponowano nowe struktury kanoniczne eliptycznych filtrów Gm-Crzędów nieparzystych. Opracowane układy filtrów wymagają małej liczby elementów zarówno aktywnych jak i pasywnych niezbędnych do realizacji żądanych charakterystyk częstotliwościowych.W pracy są również zaprezentowane rezultaty porównań właściwości przedstawionych struktur z przykładami realizacji układowych innych filtrów Gm-C.
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Algebraic model of continuous time Gm-LC filters and applications.
PublicationW pracy zaprezentowano model algebraiczny filtrów Gm-LC czasu ciągłego i jego wybrane zastosowania. Zaproponowany model obejmuje struktury pracujące zarówno w trybie napięciowym jak i prądowym. Użyteczność opracowanego modelu potwierdzono na przykładzie syntezy eliptycznego filtru Gm-LC rzędu nieparzystego.
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Structure generation and performance comparison of elliptic Gm-C filters.
PublicationW oparciu o zestaw macierzy opisujący ogólną topologię filtrów typu Gm-C opracowano procedurę efektywnej generacji struktur filtrów dolnoprzepustowych. Dla filtrów tego typu podano wyrażenia pozwalające analizować właściwości wrażliwościowe oraz określono zestaw odpowiednich kryteriów porównawczych. Szczegółowe badania porównawcze przeprowadzono dla wybranych filtrów 3-go rzędu w tym realizowanych w strukturach LF(leapfrog) i...
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Design of waveguide filters using multiple irises and folded elements.
PublicationW pracy został zaprezentowany przegląd metod projektowania filtrów falowodowych w kontekście zarówno klasycznych metod syntezy jak i współczesnych algorytmów. W szczególności rozważonoanalizę filtrów z wieloaperturowymi przegrodami oraz filtrówzbudowanych w wygiętych odcinkach falowodów. Zaprezentowano przykłady w pełni wykorzystujące zalety wygiętych falowodów a także pokazano wydajne metody optymalizacji oparte na badaniu położeń...
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Nonlinear distortion analysis and optimisation of general OTA-C filters.
PublicationW pracy przedstawiono opis analityczny ogólnej struktury filtrów OTA-C zawierających nieliniowe elementy aktywne. Wprowadzono nieliniowy układ równań różniczkowych zwyczajnych opisujący dynamikę tej klasy układów aktywnych. Opis ten pozwala, przy użyciu standardowych metod numerycznych, na przeprowadzenie efektywnej analizy czasowej filtrów OTA-C. Proponowane podejście może być stosowane do badania dowolnych efektów nieliniowych...
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Canonic structures of odd-order elliptic Gm-C filters.
PublicationW pracy zaproponowano nowe rozwiązania układowe struktur kanonicznych eliptycznych filtrów Gm-C czasu ciągłego, rzedu nieparzystego. Opracowane struktury charakteryzują się małą liczbą elementów pasywnych oraz aktywnych i są przewidziane do zastosowań w filtrach niskomocowych o małej wrażliwości. W przeprowadzonych badaniach porównywano wybrane struktury 3-go rzędu pod względem właściwości i wymagań układów scalonych, w których...
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Analysis and Optimization of Noise in Continuous-Time OTA-C Filters
PublicationW pracy przedstawiono ogólną procedurę analizy szumów w filtrach klasy OTA-C czasu ciągłego. Procedura umożliwia analizę filtrów o dowolnej topologii i dowolnego rzędu w ramach rozważanej klasy. W oparciu o opis macierzowy ogólnej struktury filtru OTA-C wyprowadzono ogólne formuły pozwalające na wyznaczanie i optymalizację szumów dowolnego filtru OTA-C. Przedstawione wyniki są użyteczne nie tylko dla klasycznych (dyskretnych lub...
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Eigenvalue approach to synthesis of prototype filters with source/load coupling
PublicationArtykuł przedstawia nową, szybko zbieżną, technikę syntezy macierzy sprzężeń filtrów o charaktrystyce Czebyszewa. Synteza opiera się na zastosowaniu metody najmniejszych kwadratów w odniesieniu do wartości własnych macierzy sprzężeń oraz jej podmacierzy.
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Noise Analysis and Optimization of Continuous-Time OTA-C Filters
PublicationW pracy przedstawiono efektywną procedurę wyznaczania szumów w filtrach OTA C czasu ciagłego. Procedura wyprowadzona jest w oparciu o ogólny model filtru OTA C oraz jego opis macierzowy. Podano jawne formuły pozwalające okreslić odniesione do wejścia widmo szumów dowolnego filtru rozważanej klasy. Otrzymane wyniki teoretyczne zostały zweryfikowane poprzez porównanie z wynikami otrzymywanymi za pomocą symulatora SPICE dla wybranych...
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Surgical tool tracking by on-line selection of structural correlation filters
PublicationIn visual tracking of surgical instruments, correlation filtering finds the best candidate with maximal correlation peak. However, most trackers only consider capturing target appearance but not target structure. In this paper we propose surgical instrument tracking approach that integrates prior knowledge related to rotation of both shaft and tool tips. To this end, we employ rigid parts mixtures model of an instrument. The rigidly...
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Determination of volatile organic compounds in water samples using membrane-solid phase microextraction (M-SPME) (headspace version)
PublicationThe results of a study on the use of membrane-solid phase microextraction (M-SPME) for sampling volatile organic compounds (VOCs) from the headspace above the liquid medium are presented. The sampled VOCs were subsequently quantified by gas chromatography (GC). Two systems were compared in this study, i.e. a novel two-phase sorption system (M-SPME), and a commercial fibre. Headspace sampling using SPME was optimized with respect...
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Roadmap on dynamics of molecules and clusters in the gas phase
PublicationThis roadmap article highlights recent advances, challenges and future prospects in studies of the dynamics of molecules and clusters in the gas phase. It comprises nineteen contributions by scientists with leading expertise in complementary experimental and theoretical techniques to probe the dynamics on timescales spanning twenty orders of magnitudes, from attoseconds to minutes and beyond, and for systems ranging in complexity...
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Buckling resistance of a metal column in a corrugated sheet silo - experiments and non-linear stability calculations
PublicationThe results of experimental and numerical tests of a single corrugated sheet silo column’s buckling resistance are presented in this study. The experiments were performed in a real silo with and without bulk solid (wheat). A very positive impact of the bulk solid on the column buckling resistance occurred. The experimental results were first compared to the buckling resistance calculated by Eurocode 3 formulae. The comparison revealed that...
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Linear game non-contextuality and Bell inequalities—a graph-theoretic approach
PublicationWe study the classical and quantum values of a class of one-and two-party unique games, that generalizes the well-known XOR games to the case of non-binary outcomes. In the bipartite case the generalized XOR(XOR-d) games we study are a subclass of the well-known linear games. We introduce a 'constraint graph' associated to such a game, with the constraints defining the game represented by an edge-coloring of the graph. We use the...
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Green aspects, developments and perspectives of liquid phase microextraction techniques
PublicationDetermination of analytes at trace levels in complex samples (e.g. biological or contaminated water or soils) are often required for the environmental assessment and monitoring as well as for scientific research in the field of environmental pollution. A limited number of analytical techniques are sensitive enough for the direct determination of trace components in samples and, because of that, a preliminary step of the analyte...
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Comparison of noise reduction methods in radiometric correlation measurements of two-phase liquid-gas flows
PublicationTwo-phase liquid-gas flows occur frequently in the mining, energy, chemical, and petrochemical industries. One of non-contact methods used to analyse these flows is the gamma ray absorption method. However, the signals received from radiation detectors contain a significant stochastic noise, which makes them difficult to analyse. The article describes four methods of noise reduction in cross-correlation measurements of water-air...
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Mitigating the seismic pounding of multi-story buildings in series using linear and nonlinear fluid viscous dampers
PublicationSeismic-induced pounding between adjacent buildings may have serious consequences, ranging from minor damage up to total collapse. Therefore, researchers try to mitigate the pounding problem using different methods, such as coupling the adjacent buildings with stiff beams, connecting them by using viscoelastic links, and installing damping devices in each building individually. In the current paper, the effect of using linear and...
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On continuity conditions at the phase interface of two-phase elastic shells
PublicationW pracy rozwinięto ogólną nieliniową teorię powłok sprężystych podlegających przejściom fazowym typu martenzytowego. Przedstawione sformułowanie oparte jest na statycznie i kinematycznie ścisłym modelu powłokowym. Uwzględniono gęstośc energii odkształcenia, jak również siły i momenty zadane wzdłuż krzywoliniowego przejścia fazowego. W szczególności otrzymano statyczne warunki ciągłości wzdłuż koherentnego połączenia oraz połączenia...
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New Method of Non-Linear Electrochemical Impedance Spectroscopy with an Amplitude-Modulated Perturbation Signal
PublicationThe paper presents a new method of non-linear electrochemical impedance spectroscopy (NLEIS), which allows fast and nondestructive evaluation of the corrosion rate and determination of the Tafel coefficients values for a corrosion system under investigation. This method employs amplitude modulation of the ac perturbation signal. The study demonstrated that it was possible to obtain impedance characteristic as a function of the...
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Fault-tolerant performance of the novel five-phase doubly-fed induction generator
PublicationThe article presents the concept of a new design of a multi-phase doubly-fed induction generator (DFIG). The innovative design approach uses a five-phase power supply from the rotor side of the generator with a three-phase classic stator power supply. Modern three-phase doubly-fed induction generators are the dominant choice for Wind Energy Conversion Systems (WECS). Solutions of this type are sensitive to the loss of at least...
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Buckling of frame braced by linear elastic springs
PublicationIn the design codes and specifications, simplifed formulae or diagrams are given for determining the buckling lengths of frame columns based on the ruling criterion of considering frames as sway or non sway. Due to the fact that, the code formulae utilize onlylocal stifness distributions, these formulae may yield in certain cases rather erroneous results. In most code formulas a case of weakly braced frames is usually not considered.In...
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On statistical linear inverse problems in fishery acoustic
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International Linear Collider Global and Local Implications
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International Linear Collider Global and Local Implications
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Stochastic approach to the dynamics of a linear floating object
PublicationArtykuł stanowi prezentację metody różniczkowych równań stochastycznych w zastosowaniu do analizy dynamiki obiektów pływających. Analizowany jest ruch jednostki pływającej jako obiektu liniowego z uwzględnieniem w równaniach stochastycznych nieliniowości, występującej w wymuszeniach zewnętrznych działających na obiekt. Stochastyczne równania różniczkowe są zapisane dla sprzężonych ruchów symetrycznych.
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Linear and nonlinear Stark effect in a triangular molecule
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Analysis of Properties of an Active Linear Gesture Sensor
PublicationBasic gesture sensors can play a significant role as input units in mobile smart devices. However, they have to handle a wide variety of gestures while preserving the advantages of basic sensors. In this paper a user-determined approach to the design of a sparse optical gesture sensor is proposed. The statistical research on a study group of individuals includes the measurement of user-related parameters like the speed of a performed...
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The high impedance measuring probe for gain-phase analysers.
PublicationAutorzy opracowali tanią sondę pomiarową przeznaczoną do pracy z analizatorami gain-phase jak Solartron 1260 Impedance/Gain-phase Analyser, 1255 Frequency Response Analyser (FRA) lub starszymi wersjami 1250, 1253. Przedstawiona architektura sondy wyznacza jej parametry metrologiczne. Pomiary możliwe są w 8 zakresach obejmujących wartości 100ohm<|Zx|<100Gohm w szerokim zakresie częstotliwości 10uHz-1MHz. Obwód wejściowy sondy pozwala...
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Novel sorptive extraction techniques in bioanalysis evaluated by Blue Applicability Grade Index: The paradigm of fabric phase sorptive extraction and capsule phase microextraction
PublicationFabric phase sorptive extraction (FPSE) and capsule phase microextraction (CPME) are two sol-gel derived microextraction techniques that emerged in the last decade towards the minimization of the environmental impact of conventional sample preparation approaches. Complementary to the well-established green metric tools, Blue Applicability Grade Index (BAGI) was recently proposed for the evaluation of method’s practicability. In...
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Optimization of Data Assignment for Parallel Processing in a Hybrid Heterogeneous Environment Using Integer Linear Programming
PublicationIn the paper we investigate a practical approach to application of integer linear programming for optimization of data assignment to compute units in a multi-level heterogeneous environment with various compute devices, including CPUs, GPUs and Intel Xeon Phis. The model considers an application that processes a large number of data chunks in parallel on various compute units and takes into account computations, communication including...
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Single and Three -Phase PWM AC/AC Converters as Semiconductor Transformers
PublicationAC voltage transformation circuits contain pure or reactance PWM AC/AC converters. These circuits can be treated as AC/AC semiconductor transformers. This paper reviews single-phase and three-phase topologies: both non-isolated and isolated, single as well as two quadrant structure. Additionally, this paper present selected examples of their applications.
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Sputtered silicon solid phase microextraction fibers with a polydimethylsiloxane stationary phase with negligible carry-over and phase bleed
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Exact resultant equilibrium conditions in the non-linear theory of branching and self-intersecting shells
PublicationWe formulate the exact, resultant equilibrium conditions for the non-linear theory of branching and self-intersecting shells. The conditions are derived by performing direct through-the-thickness integration in the global equilibrium conditions of continuum mechanics. At each regular internal and boundary point of the base surface our exact, local equilibrium equations and dynamic boundary conditions are equivalent, as expected,...
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Effect of Linear Energy and Microstructure on the Content of Residual Hydrogen in Welded Joints made of Superduplex Steels
PublicationThe article presents tests concerning the content of retained hydrogen present in FCAW and SAW welded joints made of superduplex steel. The use of various welding technologies resulted in the obtainment of welds having different microstructures and ferrite contents. Measurements of retained hydrogen present in joints (performed using the complete combustion method) revealed various contents of hydrogen in the base material and...
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Determination of Butyltin Species in Sea Water Samples Using Solid Phase Extraction Followed by Liquid Chromatography - Tandem Mass Spectrometry
PublicationReverse phase liquid chromatography (RP-HPLC)-electrospray ionization-tandem mass spectrometry (ESI-MS-MS) was evaluated for the analysis of TBT using solid phase extraction as sample preparation method. TBT was extracted from acidified water samples (spiked with tripropyltin as internal standard) using reversed phase polymeric Strata-X cartridges. Analytes were eluted from cartridges using acetonitrile-water mixture and the volume...
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Utilization of a Non-Linear Error Function in a Positioning Algorithm for Distance Measurement Systems Designed for Indoor Environments
PublicationA new positioning algorithm for distance measurement systems is outlined herein. This algorithm utilizes a non-linear error function which allows us to improve the positioning accuracy in highly difficult indoor environments. The non-linear error function also allows us to adjust the performance of the algorithm to the particular environmental conditions. The well-known positioning algorithms have limitations, mentioned by their...