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Search results for: inverter output filter
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Relationship between heart rate variability, blood pressure and arterial wall properties during air and oxygen breathing in healthy subjects
PublicationPrevious studies reported that normobaric hyperoxia influences heart rate, arterial pressure, cardiac output and systemic vascular resistance, but the mechanisms underlying these changes are still not fully understood. Several factors are considered including degeneration of endothelium-derived nitric oxide by reactive oxygen species, the impact of oxygen-free radicals on tissues and alterations of autonomic nervous system function....
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Towards the boundary between easy and hard control problems in multicast Clos networks
PublicationIn this article we study 3-stage Clos networks with multicast calls in general and 2-cast calls, in particular. We investigate various sizes of input and output switches and discuss some routing problems involved in blocking states. To express our results in a formal way we introduce a model of hypergraph edge-coloring. A new class of bipartite hypergraphs corresponding to Clos networks is studied. We identify some polynomially...
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Size Reduction of Microwave Couplers by EM-Driven Optimization
PublicationThis work addresses simulation-driven design optimization of compact microwave couplers that explicitly aims at circuit footprint area reduction. The penalty function approach allows us to minimize the area of the circuit while ensuring a proper power division between the output ports and providing a sufficient bandwidth with respect to return loss and isolation around the operating frequency. Computational cost of the optimization...
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Alternative cogeneration thermodynamic cycles for domestic ORC
PublicationThe Organic Flash Cycle (OFC) is suggested as a vapor power cycle that could potentially improve the efficiency of utilization of the heat source. Low and medium temperature finite thermal sources are considered in the cycle. Additionally the OFC’s aim is to reduce temperature difference during heat addition. The study examines 2 different fluids. Comparisons are drawn between the OFC and an optimized basic Organic Rankine Cycle...
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Low cost set-up for supercapacitors parameters evaluation
PublicationWe propose a use of a power amplifier in the circuit of voltage to current converter (current driver) for supercapacitor charging/discharging in controlled conditions. The current driver is controlled by DAC output of DAQ board and voltage of DUT is measured and a control loop is realized by software. In the circuit the DC current method of evaluation of capacitance and equivalent series...
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Wroclaw University of Technology Knowledge Repository - project objectives
PublicationKnowledge Repository is a project created in the Library and Scientific Information Centre of Wroclaw University of Technology (WrUT). Its main task will be collecting, sharing, and promoting scientific publications of researchers, postgraduates and students of WrUT. It will be also used for bibliometric analysis and reporting research output of WrUT scientific community.Knowledge Repository will closely cooperate with other databases...
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Performance of a single layer fuel cell based on a mixed proton-electron conducting composite
PublicationMany of the challenges in solid oxide fuel cell technology stem from chemical and mechanical incompatibilities between the anode, cathode and electrolyte materials. Numerous attempts have been made to identify compatible materials. Here, these challenges are circumvented by the introduction of a working single layer fuel cell, fabricated from a composite of proton conducting BaCe0.6Zr0.2Y0.2O3-δ and a mixture of semiconducting...
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Displacement Sensors Based on the Phase of the Reflection Coefficient of a Split Ring Resonator Loaded Transmission Line
Publication— In this paper, novel displacement sensors using a microstrip loaded with a pair of split ring resonators (SRRs) are proposed. It is shown that the phase of the reflection coefficient from the loading SRRs can be used for displacement sensing. The paper also proposes a differential version of the sensor that benefits from a higher sensitivity and reference zero, which is useful for alignment purposes. It is further shown that...
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Application of thin diamond films in low-coherence fiber-optic Fabry Pérot displacement sensor
PublicationThe novel fiber-optic low coherence sensor with thin diamond films is demonstrated. The undoped and boron-doped diamond films were elaborated by the use of the microwave plasma enhanced chemical vapor deposition (μPE CVD) system. The optical signal from the Fabry–Pérot cavity made with the application of those thin films is sensitive to displacement. The sensor characterization was made in the range of 0–600 μm. The measurements...
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Detekcja i lokalizacja nieprzewodzenia tranzystorów falownika napięcia na podstawie analizy prądu obciążenia
PublicationPrzedstawiono nową metodę detekcji i lokalizacji nieprzewodzenia tranzystorów w falownikach napięcia zasilających silniki indukcyjne małej mocy. Metoda bazuje na monitorowaniu wartości dwóch sygnałów dia-gnostycznych. Pierwszy z nich, wskaźnik braku przepływu prądu, wykorzystano w celu detekcji uszkodzeń. Drugi, stosunek wartości średniej prądu do wartości średniej bezwzględnej, zawiera informacje umożliwiające lokalizację uszkodzonych...
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Piękno i Energia – odnalezione wartości w budowaniu współczesnego miejskiego środowiska zamieszkania
Publication.
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Rozprzestrzenianie się w podtorzu skutków katastrof kolejowych z udziałem materiałów niebezpiecznych
PublicationDuża część przewozów materiałów niebezpiecznych prowadzona jest koleją. W związku z tym bezpieczeństwo tych przewozów nabiera coraz większego znaczenia. Każda katastrofa z udziałem materiałów niebezpiecznych ma negatywny wpływ na uczestników tego zdarzenia oraz na otaczające środowisko, bowiem jej zasięg na ogół nie jest lokalny. Z tego wynika, że w przypadku zaistnienia katastrofy należy minimalizować jej skutki oraz w dalszych...
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Knowledge Management for Managing Crisis in Tourism: Theoretical insights
PublicationCOVID-19 has caused an unprecedented crisis affecting the entire tourism industry. Accommodation, food, and travel sectors have been affected by the decreased number of visitors, which had a ripple effect on the financial situation of the whole industry. The purpose of this work is a better understanding of the role of knowledge management in terms of mitigating the crisis in the tourism sector, as well as a development of the...
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Napęd z silnikiem indukcyjnym i 4-gałęziowym falownikiem SiC do turbosprężarek powietrza ogniw paliwowych dużej mocy
PublicationWysoka cena ogniw paliwowych utrudnia ich szerokie zastosowanie w transporcie i przemyśle. Należy szukać możliwości obniżenia ich kosztu również poprzez obniżenie kosztu i zwiększenie wydajności urządzeń pomocniczych ogniwa paliwowego (Balance of the Plant). Autorzy proponują aby w napędzie sprężarki powietrza, zastosować wysokoobrotowy silnik indukcyjny, który jest tańszy od stosowanych obecnie silników PMSM. W referacie zaproponowano...
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Parameters of land reference points in the Gdynia region and the Free-air anomaly grid of the South Baltic
Open Research DataThe data was registered during the campaign to verify the catalog value of the absolute point coordinates [point 5403 (POLREF-GORA DONAS)] of the national gravimetric control network. The data was recorded in two three-hour stationary measurement campaigns at the following points: Rozewie of the EUREF-POL network, Góra Donas POLREF, and mareograph points...
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The data exchange between smart glasses and healthcare information systems using the HL7 FHIR standard
PublicationIn this study we evaluated system architecture for the use of smart glasses as a viewer of information, as a source of medical data (vital sign measurements: temperature, pulse rate, and respiration rate), and as a filter of healthcare information. All activities were based on patient/device identification procedures using graphical markers or features based on visual appearance. The architecture and particular use cases were implemented...
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ANALIZA NIELINIOWEGO OBSERWATORA I FILTRU CZĄSTECZKOWEGO JAKO ESTYMATORÓW POZYCJI STATKU.
PublicationW artykule została przedstawiona analiza porównawcza dokonana pomiędzy dwoma estymatorami pozycji. Analiza ta została przedstawiona na podstawie różnicy pomiędzy wartością estymowaną a rzeczywistą. Badania estymatorów zostały przeprowadzone na podstawie równania kinematyki i dynamiki statku dynamicznie pozycjonowanego. Wartościami wykorzystywanymi w symulacji są pomiary z symulowanego odbiornika GPS i siły wytworzone przez napędy...
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Two-Step Model Based Adaptive Controller for Dissolved Oxygen Control in Sequencing Wastewater Batch Reactor
PublicationDissolved Oxygen (DO) concentration is a crucial parameter for efficient operation of biological processes taking place in the activated sludge Wastewater Treatment Plant (WWTP). High-quality DO control is difficult to achieve because of complex nonlinear behavior of the plant and substantial influent disturbances. A method to improve the Direct Model Reference Adaptive Control (DMRAC) technology in application to DO tracking for...
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Multi-Fidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
PublicationIn order to minimize the number of evaluations of high-fidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computational-efficient multi-fidelity local surrogate-model optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multi-fidelity coarse models and polynomial interpolation...
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Parametrized Local Reduced-Order Models With Compressed Projection Basis for Fast Parameter-Dependent Finite-Element Analysis
PublicationThis paper proposes an automated parametric local model-order reduction scheme for the expedited design of microwave devices using the full-wave finite-element method (FEM). The approach proposed here results in parameterized reduced-order models (ROMs) that account for the geometry and material variation in the selected subregion of the structure. In each subregion, a parameter-dependent projection basis is generated by concatenating...
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MICROSEISMIC EVENT DETECTION USING DIFFERENT ALGORITHMS ON REAL DATA FROM PATCH ARRAY GEOPHONE GRID FROM EASTERN POMERANIA FRACTURING JOB
PublicationThe microseismic monitoring is a method of monitoring of fracture propagation during hydraulic fracturing process. Hydraulic fracturing is a method of reservoir stimulation used especially for unconventional gas recovery. A matrix of several thousand geophones is placed on the surface of earth to record every little tremor of ground induced by fracturing process. Afterwards, the signal is analysed and the place of tremor occurrence...
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Miniaturized Inline Bandpass Filters Based on Triple-Mode Integrated Coaxial-Waveguide Resonators
PublicationThis work presents a design technique to implement miniaturized cross-coupled bandpass filters in inline physical configurations based on triple-mode resonators. Triple-mode resonances are obtained by using integrated coaxial-waveguide cavity resonators. They consist of two coaxial conducting posts placed in the sidewalls of a rectangular waveguide cavity. In the proposed triplet, a transmission zero (TZ) can be positioned at any...
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Effects of liquid phase modification on the performance of biotrickling filters
Open Research DataDataset presents the effects of liquid phase modification on the biotrickling filtration (BTF) performance of air polluted with toluene, ethylbenzene, xylene and styrene.
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Performance improvement of NN based RTLS by customization of NN structure - heuristic approach
PublicationThe purpose of this research is to improve performance of the Hybrid Scene Analysis – Neural Network indoor localization algorithm applied in Real-time Locating System, RTLS. A properly customized structure of Neural Network and training algorithms for specific operating environment will enhance the system’s performance in terms of localization accuracy and precision. Due to nonlinearity and model complexity, a heuristic analysis...
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NVRAM as Main Storage of Parallel File System
PublicationModern cluster environments' main trouble used to be lack of computational power provided by CPUs and GPUs, but recently they suffer more and more from insufficient performance of input and output operations. Apart from better network infrastructure and more sophisticated processing algorithms, a lot of solutions base on emerging memory technologies. This paper presents evaluation of using non-volatile random-access memory as a...
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Residual MobileNets
PublicationAs modern convolutional neural networks become increasingly deeper, they also become slower and require high computational resources beyond the capabilities of many mobile and embedded platforms. To address this challenge, much of the recent research has focused on reducing the model size and computational complexity. In this paper, we propose a novel residual depth-separable convolution block, which is an improvement of the basic...
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RSS-Based DoA Estimation for ESPAR Antennas Using Support Vector Machine
PublicationIn this letter, it is shown how direction-of-arrival (DoA) estimation for electronically steerable parasitic array radiator (ESPAR) antennas, which are designed to be integrated within wireless sensor network nodes, can be improved by applying support vector classification approach to received signal strength (RSS) values recorded at an antenna's output port. The proposed method relies on ESPAR antenna's radiation patterns measured...
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Multi-Criteria Knowledge-Based Recommender System for Decision Support in Complex Business Processes
PublicationIn this paper, we present a concept of a multi-criteria knowledge-based Recommender System (RS) designed to provide decision support in complex business process (BP) scenarios. The developed approach is based on the knowledge aspects of Stylistic Patterns, Business Sentiment and Decision-Making Logic extracted from the BP unstructured texts. This knowledge serves as an input for a multi-criteria RS algorithm. The output is prediction...
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Low-fidelity model considerations for simulation-based optimisation of miniaturised wideband antennas
PublicationHere, variable-fidelity electromagnetic (EM)-based design optimisation of miniaturised antennas is discussed. The authors focus on an appropriate selection of discretisation density of the low-fidelity EM model, which results in good performance of the optimisation algorithm in terms of its computational complexity and reliability. Trust-region gradient search with low-fidelity model corrected by means of non-linear frequency scaling...
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On low-fidelity models for variable-fidelity simulation-driven design optimization of compact wideband antennas
PublicationThe paper addresses simulation-driven design optimization of compact antennas involving variable-fidelity electromagnetic (EM) simulation models. Comprehensive investigations are carried out concerning selection of the coarse model discretization density. The effects of the low-fidelity model setup on the reliability and computational complexity of the optimization process are determined using a benchmark set of three ultra-wideband...
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The impacts of final demands changes on the total outputs of Japanese industrial sectors: A further study
PublicationThe purpose of the current study is to expand the previous studies which analyze the impacts of final demands changes on the total outputs of industrial sectors of a specific country. More specifically, the study conducts the analysis regarding the impacts on the total outputs of Japanese industries. The study employs a demand-pull Input-Output (IO) quantity model, one of the calculation tools in the IO analysis. The study focuses...
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Response of a fiber-optic Fabry-Pérot interferometer to refractive index and absorption changes – modelling and experiments
PublicationThis paper describes how the refractive index and the absorption of investigated substances change the spectrum of the optical radiation at the output of the fiber-optic Fabry-Pérot interferometer. The modeling of the operation of the interferometer takes into account not only the spectra of the refractive index and the absorption of the medium that is inside the cavity, but also spectra of the refractive indices of the core and...
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The impacts of final demands changes on the total outputs of Japanese industrial sectors: A further study
PublicationThe purpose of the current study is to expand the previous studies which analyze the impacts of final demands changes on the total outputs of industrial sectors of a specific country. More specifically, the study conducts the analysis regarding the impacts on the total outputs of Japanese industries. The study employs a demand-pull Input-Output (IO) quantity model, one of the calculation tools in the IO analysis. The study focuses...
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Balancing Energy Inputs/Outputs and GHG Emissions for Sustainable Wastewater Treatment – a Case Study
PublicationThe aim of the study is a model-based evaluation of the selected operating modes and technological upgrades on the energy balance and greenhouse gas (GHG) emissions in a large wastewater treatment plant in the city of Slupsk (northern Poland). The considered scenarios focus on energy savings for aeration, increasing energy recovery via biogas cogeneration and reduction of the CO2 equivalent emission from both direct processes (related...
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Digital Processing of Frequency–Pulse Signal in Measurement System
PublicationThe work presents the issue of the use of multichannel measurement systems of sensors processing input value to impulse signal frequency. The frequency impulse signal obtained from such sensors is often required to be processed at the same time with a voltage signal which is obtained from other sensors used in the same measurement system. In such case, it is usually necessary to sample the output signals from all sensors in the...
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Fast Real-Time RDFT- and GDFT-Based Direct Fault Diagnosis of Induction Motor Drive
PublicationThis paper presents the theoretical analysis and experimental verification of a direct fault harmonic identification approach in a converter-fed electric drive for automated diagnosis purposes. On the basis of the analytical model of the proposed real-time direct fault diagnosis, the fault-related harmonic component is calculated using recursive DFT (RDFT) and Goertzel DFT (GDFT), applied instead of the full spectrum calculations...
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Broken rotor symptoms in the sensorless control of induction machine
PublicationThe purpose of this paper is to investigate the need for a universal method for sensorless controlled induction motor drive diagnosis. The increasing number of sensorless control systems in industrial applications require a universal method for the drive diagnosis, which provides reliable diagnostic reasoning independent of control system structure and state variables measurement or estimation method.Simulations and experimental...
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Dual Active Bridge (DAB) DC-DC converter for multilevel propulsion converters for electrical multiple units (EMU)
PublicationSemiconductor power devices made from silicon carbide (SiC) reached a level of technology enabling their widespread use in power converters. Two different approaches to implementation of modern traction converters in electric multiple units (EMU) have been presented in recent years: (i) 3.3-kV SiC MOSFET-based three-level PWM inverter with regenerative braking and (ii) 6.5-kV IGBT-based four-quadrant power electronic traction transformer...
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Simulations of flows in the coastal zone of the Baltic Sea
Open Research DataThe study area is located in the Southern Baltic, within Polish Marine Areas, adjacent to the coastline in the vicinity of Lubiatowo village, where The Coastal Research Station (CRS) – a field laboratory of the Institute of Hydro-Engineering of the Polish Academy of Sciences (IBW PAN) –is situated. The numerical reconstruction of the coastal flow was...
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Analiza wydajności kolektora słonecznego przeznaczonego dla systemu ogrzewania budynku o niskim zapotrzebowaniu na ciepło
PublicationNiniejsza praca przedstawia wyniki badań numerycznych kolektora słonecznego, przeznaczonego dla budynków o niskim zapotrzebowaniu na ciepło. W pracy przedstawiono nowatorską koncepcję kolektora słonecznego o obniżonej wydajności, niskich kosztach wykonania oraz wykorzystującego istniejące elementy konstrukcji przekryć budynku. Istotną zaletą kolektora jest brak ingerencji w architekturę zewnętrzną budynku. Za pomocą symulacji numerycznej...
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New patterns in the position of CEE countries in global value chains: functional specialisation approach
PublicationResearch background: High servitisation of manufacturing makes it impossible to separate services from manufactured goods properly, which implies difficulties in the assessment of the position of the country on the smile curve, i.e. in the proper assignment of products or services to one of the industrial process steps: pre-production, pure fabrication or post-production services. Therefore, we propose to use the business functions...
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Smart acoustic band structures
PublicationSmart acoustic band structures exhibit very interesting and non-standard physical properties due to the periodic nature of their certain characteristic on different scale levels. They manifest mostly in their frequency spectra as socalled frequency band-gaps or stop-bands, what has a great impact on the behaviour of these structures in relation to the propagation of vibro-acoustic signals that can be transmitted through the structures...
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Planar Microwave Bragg Reflector Resonant Dielectric Sensor
PublicationIn this paper, a periodic structure is used to design a microwave Bragg reflector with the help of hexagonal lattice, which provides a 5 GHz wide stopband between the low-pass band with cut-off frequency 2.6 GHz and the bandpass response with start and stop frequency 7.8 GHz and 10.5 GHz, respectively. A defect in lattice allows passing a narrowband signal at 6 GHz which is found, from the dispersion relation, to be in the region...
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A Novel Coupling Matrix Synthesis Technique for Generalized Chebyshev Filters With Resonant Source–Load Connection
PublicationThis paper reports a novel synthesis method for microwave bandpass filters with resonant source–load connection. In effect, a network realizing N+1 transmission zeros (where N is the number of reflection zeros) is obtained. The method is based on a prototype transversal coupling matrix (N+2, N+2) with source and load connected by a resonant circuit formed by a capacitor in parallel with a frequency-invariant susceptance. To complement...
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Visualization of short-term heart period variability with network tools as a method for quantifying autonomic drive
PublicationWe argue that network methods are successful in detecting nonlinear properties in the dynamics of autonomic nocturnal regulation in short-term variability. Two modes of visualization of networks constructed from RR-increments are proposed. The first is based on the handling of a state space. The state space of RR-increments can be modified by a bin size used to code a signal and by the role of a given vertex as the representation...
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Potential of novel atomic emission techniques as a tool for investigation of the possibilities of using industrial waste as additives in construction materials
PublicationNowadays, due to the global ecological crisis and ways to prevent a climate disaster, more and more attention is paid to green techno-logies and green Chemistry, which are part of the so-called “The Green Deal.” The main assumption is the optimization of the processes of producing necessary goods and the implementation of methods of managing postproduction waste in the least environmentally harmful manner. In the presented research,...
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Wavelet filtering of signals without using model functions
PublicationThe effective wavelet filtering of real signals is impossible without determining their shape. The shape of a real signal is related to its wavelet spectrum. For shape analysis, a continuous color wavelet spectrogram of signal level is often used. The disadvantage of continuous wavelet spectrogram is the complexity of analyzing a blurry color image. A real signal with additive noise strongly distorts the spectrogram based on continuous...
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Application of H2O2 to optimize ammonium removal from domestic wastewater
PublicationThe paper presents the results of application of hydrogen peroxide (H2O2) for the optimization of the effects of ammonia nitrogen removal from domestic wastewater. The investigations were carried out at a model wastewater treatment plant consisting of a preliminary sedimentation tank and a sand filter with a horizontal flow of wastewater at a constant hydraulic load of 1.44 L/day. The efficiency of ammonia nitrogen removal was...
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Canonical switched capacitor converters. Comments, complements, and refinements
PublicationSwitched Capacitor Converters (SCC) form useful blocks in low/medium power applications as they are suitable for integration, both as off-chip and on-chip IC realizations. However, the problem with SCC is that their voltage conversion ratio is topology-dependent. By changing the SC circuit configuration, we can gain control over voltage conversion but the available ratio remains of a discrete nature, i.e. it maps into a countable...
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Continuous blood pressure monitoring by photoplethysmography - signal preprocessing requirements based on blood flow modelling
PublicationObjective. The aim of the study is to investigate the effect of the signal sampling frequency and low-pass filtering on the accuracy of the localisation of the fiducial points of the photoplethysmographic signal (PPG), and thus on the estimation of the blood pressure (i.e. the accuracy of the estimation). Approach. Statistical analysis was performed on 3,799 data samples taken from a publicly available database. Four PPGfiducial...