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Wyniki wyszukiwania dla: WAVE FILTERING
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Statistically efficient smoothing algorithm for time-varying frequency estimation
PublikacjaThe problem of extraction/elimination of a nonstationary sinusoidal signal from noisy measurements is considered. This problem is usually solved using adaptive notch filtering (ANF) algorithms. It is shown that the accuracy of frequency estimates can be significantly increased if the results obtained from ANF are backward-time filtered by an appropriately designed lowpass filter. The resulting adaptive notch smoothing (ANS) algorithm...
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Detection and segmentation of moving vehicles and trains using Gaussian mixtures, shadow detection and morphological processing
PublikacjaSolution presented in this paper combines background modelling, shadow detection and morphological and temporal processing into one system responsible for detection and segmentation of moving objects recorded with a static camera. Vehicles and trains are detected based on their pixellevel difference from the continually updated background model utilizing a Gaussian mixture calculated separately for every pixel. The shadow detection...
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A self-optimization mechanism for generalized adaptive notch smoother
PublikacjaTracking of nonstationary narrowband signals is often accomplished using algorithms called adaptive notch filters (ANFs). Generalized adaptive notch smoothers (GANSs) extend the concepts of adaptive notch filtering in two directions. Firstly, they are designed to estimate coefficients of nonstationary quasi-periodic systems, rather than signals. Secondly, they employ noncausal processing, which greatly improves their accuracy and...
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Matrix-based robust joint fingerprinting and decryption method for multicast distribution of multimedia
PublikacjaThis 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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Parametric versus nonparametric modelling of dynamic susceptibility contrast enhanced MRI based data
PublikacjaDynamic tracking of a bolus of a paramagnetic agent (dynamic susceptibility contract - DSC) in MRI (magnetic resonance imaging) measurements is successfully used for assessment of the tissue perfusion and the other features and functions of the brain (i.e. cerebral blood flow - CBF, cerebral blood volume - CBV, mean transit time - MTT). The parametric and nonparametric approaches to the identification of MRI models are presented...
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Application of Rapid Prototyping technology in the manufacturing of turbine blade with small diameter holes
PublikacjaThe article presents the possibilities of using Rapid Prototyping (RP) technology in the manufacturing of turbine blades with small diameter holes. The object under investigation was gas turbine blade with small diameter cooling holes and holes for generating longitudinal vortices. A turbine blade model was produced by means of Direct Metal Laser Sintering (DMLS) technology and subsequently validated in terms of detection and accuracy...
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Wczesne wykrywanie spoofingu GNSS typu carry-off
PublikacjaW referacie przedstawiono klasyfikację ataków typu spoofing ukierunkowanych na odbiorniki satelitarnych systemów nawigacyjnych GNSS. W szczególności opisano zaawansowaną formę spoofingu w wariancie tzw. carry-off, polegającym na płynnym przejęciu kontroli nad blokami śledzenia sygnałów w zakłócanym odbiorniku. Sposób realizacji takiego ataku istotnie utrudnia jego wykrycie z użyciem metod dotychczas proponowanych w literaturze....
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Metal–Organic Frameworks (MOFs) for Cancer Therapy
PublikacjaMOFs exhibit inherent extraordinary features for diverse applications ranging from catalysis, storage, and optics to chemosensory and biomedical science and technology. Several procedures including solvothermal, hydrothermal, mechanochemical, electrochemical, and ultrasound techniques have been used to synthesize MOFs with tailored features. A continued attempt has also been directed towards functionalizing MOFs via “post-synthetic...
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Absorbing Boundary Conditions Derived Based on Pauli Matrices Algebra
PublikacjaIn this letter, we demonstrate that a set of absorbing boundary conditions (ABCs) for numerical simulations of waves, proposed originally by Engquist and Majda and later generalized by Trefethen and Halpern, can alternatively be derived with the use of Pauli matrices algebra. Hence a novel approach to the derivation of one-way wave equations in electromagnetics is proposed. That is, the classical wave equation can be factorized...
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Fundamentals of Interpersonal Communication Group Work 24/25
Kursy OnlineThe main objective of this coure is to search information on a given topic. On this course students have to present their opinions on a specific topic in the form of a multimedia presentation. Classes are designed to improve the skills of public speaking and to acquire basic knowledge about verbal and nonverbal communication, speeches principles (rhetoric), statement ethics, the rules of disscusion, the basics of good manners....
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Fundamentals of Interpersonal Communication Group Work, PG_00041985
Kursy OnlineThe main objective of this coure is to search information on a given topic. On this course students have to present their opinions on a specific topic in the form of a multimedia presentation. Classes are designed to improve the skills of public speaking and to acquire basic knowledge about verbal and nonverbal communication, speeches principles (rhetoric), statement ethics, the rules of disscusion, the basics of good manners....
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Influence of pore formers on electrical properties of CaTi0.9Fe0.1O3-δ perovskite-type ceramics
PublikacjaPorous CaTi0.9Fe0.1O3-δ (CTF) perovskites were synthesized by the standard solid state method at different sintering temperatures with carbon black (CB), corn starch (CS) and potato starch (PS) as pore-forming agents. The ceramic samples of porosity between 9% and 42% with 5 - 40 μm pore sizes, were obtained by a 6 h sintering at either 1130º C or 1200º C of precursor powder prepared at 1470º C. X-ray diffraction analysis proved...
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Thermal Self-Action of Acoustic Beams Containing Several Shock Fronts
PublikacjaThermal self-action of an acoustic beam with one discontinuity or several shock fronts is studied in a Newtonian fluid. The stationary self-action of a single sawtooth wave with discontinuity (or some integer number of these waves), symmetric or asymmetric, is considered in the cases of self-focusing and self- defocusing media. The results are compared with the non-stationary thermal self-action of the periodic sound. Thermal self-action...
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When migrant men become more involved in household and childcare duties – the case of Polish migrants in Norway
Dane BadawczeIn our two studies, we focus on egalitarian attitudes towards genderrelations manifested by the readiness to share and actual share ofhousehold duties by Polish migrant couples in Norway, where wecompare their household arrangements with Polish couples inPoland to verify whether the migration to socio-democraticwelfare state country might encourage...
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Ahmer Bin Hafeez
OsobyI have experience in Computational Biology, particularly bioinformatics, homology modeling, phylogenetics, structural biology, and drug discovery. Furthermore, I have hands-on experience with Bioinformatics software. Currently, my interest lies in translatable omics studies and drug discovery against novel protein targets involved in cancer and infectious diseases and Host-Pathogen PPIs. My aim involves the use of computational...
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Proton Conducting Ceramic Powder Synthesis by a Low Temperature Method
PublikacjaMolten salt synthesis (MSS) is a simple method for the preparation of ceramic powders with specific morphology. The main role of the molten salts is to increase the reaction rate and lower the reaction temperature. It occurs because of much higher mobility of reactants in the liquid medium than in the solid state. In this work the molten salt synthesis was applied to produce ceramic powders of La0995Ca0005NbO4 and BaCe09−xZrxY01O3....
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A high-accuracy complex-phase method of simulating X-ray propagation through a multi-lens system
PublikacjaThe propagation of X-ray waves through an optical system consisting of many X-ray refractive lenses is considered. For solving the problem for an electromagnetic wave, a finite-difference method is applied. The error of simulation is analytically estimated and investigated. It was found that a very detailed difference grid is required for reliable and accurate calculations of the propagation of X-ray waves through a multi-lens...
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From the multiple frequency tracker to the multiple frequency smoother
PublikacjaThe problem of extraction/elimination of nonstationary sinusoidalsignals from noisy measurements is considered. This problem is usually solved using adaptive notch filtering (ANF)algorithms. It is shown that the accuracy of frequency estimates can be significantly increased if the results obtained from ANF are backward-time filtered by an appropriately designed lowpass filter. The resulting adaptive notch smoothing (ANS)algorithm...
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Listening to Live Music: Life beyond Music Recommendation Systems
PublikacjaThis paper presents first a short review on music recommendation systems based on social collaborative filtering. A dictionary of terms related to music recommendation systems, such as music information retrieval (MIR), Query-by-Example (QBE), Query-by-Category (QBC), music content, music annotating, music tagging, bridging the semantic gap in music domain, etc. is introduced. Bases of music recommender systems are shortly presented,...
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Flood Classification in a Natural Wetland for Early Spring Conditions Using Various Polarimetric SAR Methods
PublikacjaAbstract--- One of the major limitations of remote sensing flood detection is the presence of vegetation. Our study focuses on a flood classification using Radarsat-2 Quad-Pol data in a natural floodplain during leafless, dry vegetation (early spring) state. We conducted a supervised classification of a data set composed of nine polarimetric decompositions and Shannon entropy followed by the predictors' importance estimation to...
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Focus on Misinformation: Improving Medical Experts’ Efficiency of Misinformation Detection
PublikacjaFighting medical disinformation in the era of the global pandemic is an increasingly important problem. As of today, automatic systems for assessing the credibility of medical information do not offer sufficient precision to be used without human supervision, and the involvement of medical expert annotators is required. Thus, our work aims to optimize the utilization of medical experts’ time. We use the dataset of sentences taken...
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Effect of waviness and roughness components on transverse profiles of turned surfaces
PublikacjaThis paper presents the authors method of simultaneous analysis of roughness and waviness irregularity components, with the aim of better defining the key qualities and characteristics.Periodical surface machining traces may be analyzed spectrally, with the irregularity's peaks and troughs being used to define the wave's amplitude.In this work the standard composition for filtering waviness and roughness components of a surface...
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Highly-Compact Dual-Band Bandpass Waveguide Filter Based on Cross-Shaped Frequency-Dependent Coupling
PublikacjaThis work reports the design of an original class of highly-compact dual-band bandpass filter based on dual-mode waveguide resonators inter-coupled through a novel type of frequency-dependent coupling (FDC). The devised FDC consists of a cross-shaped metallic structure placed in the broad wall of a rectangular waveguide. This FDC produces two additional poles and three extra transmission zeros (TZs). Specifically, each pole is...
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Validation of Interpolation Algorithms for Multiscale UV-VIS Imaging Using UAV Spectrometer
PublikacjaIn this study, we present a comparison of popular methods for the interpolation of irregular spatial data in order to determine the applicability of each algorithm for hyperspectral reflectance estimation. The algorithms were benchmarked against a very high-resolution orthoimage from an RGB camera and medium-resolution satellite imagery from Sentinel-2A. We tested five interpolation algorithms: Triangulated Irregular Network (TIN),...
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Multi-objective optimization of the ORC axial turbine for a waste heat recovery system working in two modes: cogeneration and condensation
PublikacjaDue to the demand of the district heating network and electric power grid ORC turbines can operate in the condensation and cogeneration modes. This approach requires the design of an expander which is characterized by high efficiency in each mode of operation. The paper is devoted to a multi-objective efficiency optimization of a one stage axial ORC turbine working on MM (Hexamethyldisiloxane). An Implicit Filtering algorithm (IF)...
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DIAGNOSTICO EDAFOLOGICO PARA LA PLANIFICACION DE HUERTAS ORGANICAS FAMILIARES EN SUELOS PERIURBANOS
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Recurrence scheme for FDTD-compatible discrete Green's function derived based on properties of Gauss hypergeometric function
PublikacjaIn this paper, the formulation of one-dimensional FDTD (Finite-difference time-domain)-compatible discrete Green's function (DGF) is derived based on the Gauss hypergeometric function (GHF). The properties of GHF make it possible to derive the recurrence scheme only in the time domain for the DGF generation. Furthermore, this recurrence scheme is valid for any stable time-step size and can be implemented using standard numerical...
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Design of UWB coplanar antenna with reduced ground plane
PublikacjaW artykule przedstawiono projekt kompaktowej anteny szerokopasmowej złożonej z dwóch kołowych pasków koplanarnych ograniczających szczelinę o podobnym kształcie. Antena zasilona była z 50 Ω linii trójpaskowej. Przeprowadzono badania wpływu zewnętrznego paska na pasmo anteny. Zaprojektowana antena została zbadana eksperymentalnie pokazując bardzo dobre parametry: w paśmie 1.7-15.5GHz uzyskano |S11| < −10dB. Antena charakteryzowała...
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Fundamental properties of solutions to fractional-order Maxwell's equations
PublikacjaIn this paper, fundamental properties of solutions to fractional-order (FO) Maxwell's equations are analysed. As a starting point, FO Maxwell's equations are introduced in both time and frequency domains. Then, we introduce and prove the fundamental properties of electromagnetic field in FO electromagnetics, i.e. energy conservation, uniqueness of solutions, and reciprocity. Furthermore, the algorithm of the plane wave simulation...
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Rapid multi-objective design of integrated on-chip inductors by means of Pareto front exploration and design extrapolation
PublikacjaIdentification of the best trade-offs between conflicting design objectives allows for making educated design decisions as well as assessing suitability of a given component or circuit for a specific application. In case of inductors, the typical objectives include maximization of the quality factor and minimization of the layout area, as well as maintaining a required inductance at a given operating frequency. This work demonstrates...
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Investigations of nonreciprocal devices employing cylindrical ferrite coupled line junction
PublikacjaArtykuł opisuje wykorzystanie cylindrycznej sekcji ferrytowych linii sprzężonych do realizacji układów niewzajemnych. W artykule opisano proces projektowy izolatora ferrytowego wykorzystującego badaną sekcję oraz planarne układy zasilające. Uzyskane z symulacji wyniki zostały zweryfikowane eksperymentalnie.
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Scattering by an array of conducting, lossy dielectric, ferrite and pseudochiral cylinders.
PublikacjaOpisano metodę analizy rozpraszania fali elektromagnetycznej w systemach zawierających cylindryczne pręty dielektryczne, metalowe, ferytowe i pseudochiralne i wykorzystanie w/w metody w problemach zamkniętych i znajdowanie macierzy rozpraszania wieloportowych złączy falowodowych oraz w problemach otwartych i badanie charakterystyk rozpraszania zarówno w strefie dalekiej jaki bliskiej.
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Resonance microstrip structure with patch of arbitrary convex geometry with the use of field matching technique
PublikacjaAn analysis of the resonance frequency problem of planar microstrip structure with patch of arbitrary convex geometry is presented. A full-wave analysis is employed utilizing a combination of Galerkin’s moment method and field matching technique. In this approach, a field matching technique is adopted to calculate the patch surface current densities, and next the method of moments is utilized to calculate resonance frequencies...
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Finite element/mode-matching analysis of ferrite/dielectric line junctions of arbitrary cross-section
PublikacjaThis paper is focused on the analysis of line junctions obtained as a cascade of dielectric and ferrite guides of arbitrary cross-section. The main application of such structures is nonreciprocal devices such as isolators, circulators, or phase shifters. The efficient finite element/mode-matching approach is proposed to the analysis of such structures. In this approach, thefiniteelementmethod is applied todetermine propagation...
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Left-handed propagation characteristics of a dielectric and metal-loaded periodic circular waveguide
PublikacjaIn this paper, a periodic dielectric/metallic rod is located in a circular waveguide to obtain left-handed operation. Two geometries of the dielectric/metallic rod are proposed and examined. The dispersion characteristics of the investigated waveguides are obtained using a surface impedance model. Moreover, equivalent circuit models are proposed allowing for calculation of the dispersion characteristics and scattering parameters...
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Design and optimization of a novel miniaturized low-profile circularly polarized wide-slot antenna
PublikacjaThis paper presents a novel structure of a compact circularly polarized (CP) antenna. CP is obtained using a parasitic quasi-rectangular strip placed coplanar to the feedline. A ground plane perturbation combined with the asymmetric geometry of the coplanar waveguide ground planes is utilized to excite additional CP modes. All antenna dimensions are rigorously optimized to achieve the best possible performance in terms of the impedance...
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Zirconia-based mixed potential sensor with Pt electrode prepared by spin-coating of polymeric precursor
PublikacjaMany types of yttria-stabilized zirconia (YSZ) based gas sensors have been explored extensively in recent years. Great attention have been directed to mixed-potential-type gas sensors. It is due to growing concerns with environmental issues. Not without a significance is the fact of very attractive performance of this type of sensor allowing to detect low concentration of pollutant gases. In this paper two types of YSZ based mixed-potential...
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Jacek Stefański prof. dr hab. inż.
OsobyJacek Stefański ukończył studia na Wydziale Elektroniki Politechniki Gdańskiej (PG) w 1993 r. W 2000 r. uzyskał stopień doktora nauk technicznych w dyscyplinie telekomunikacja, w 2012 r. stopień doktora habilitowanego, natomiast w 2020 r. tytuł profesora nauk inżynieryjno-technicznych. Obecnie pracuje na stanowisku profesora w Katedrze Systemów i Sieci Radiokomunikacyjnych (KSiSR) PG. W latach 2005-2009 był zatrudniony w Instytucie...
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A Numerical Study on Baseline-Free Damage Detection Using Frequency Steerable Acoustic Transducers
PublikacjaIn structural health monitoring (SHM) a considerable amount of damage detection algorithms based on guided waves (GW) have been developed. Most of them rely on extensive transducer networks, besides preliminary reference measurements of the structures. This originated a growing demand for hardware simplification and cost reduction of the wave-based SHM methods, driving the conception of new solutions enabling both: the reduction...
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Damage detection in plates based on Lamb wavefront shape reconstruction
PublikacjaMany of the current studies in the area of damage detection using elastic wave propagation are based on deploying sensor networks with a large number of piezoelectric transducers to detect small-size cracks. A major limitation of these studies is that cracks are usually larger and have different shapes in real cases. Moreover, using a large number of sensing nodes for damage detection is both costly and computationally intensive....
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2 Latin letters by Georg Pauli (b.1586-d.1650) - transcription, translation and photographs
Dane BadawczeThe data set contains two Latin letters by Georg Pauli (b. 1586 – d. 1650) to his brother Adrian (d. 1622) in photographs, transcriptions, and translations into Polish and English. The first letter was sent by Georg from Gdańsk (formerly Danzig) in 1604 when he was still a student at the local Academic Gymnasium. The second one, in turn, was written...
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The potential of raw sewage sludge in construction industry – A review
PublikacjaExcess sewage sludge produced in any municipal or industrial wastewater treatment plant becomes a serious problem due to its increasing amount. This increase is related to the improvement of treatment technologies, expansion of sewage systems and the development of new industrial plants. The implementation and development of new technologies related to the utilization of sewage sludge is currently based on treating it as a substrate....
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Changes on the Surface of the SiO2/C Composite, Leading to the Formation of Conductive Carbon Structures with Complex Nature of DC Conductivity
PublikacjaSol–gel layers have been the subject of many studies in recent decades. However, very little information exists about layers in which carbon structures are developed in situ. Using the spin-coating method, we obtained thin iron-doped SiO2/C composite films. The results of Raman spectroscopy showed that our samples consisted of graphitic forms and polymers. The latter’s contribution decreases with rising temperature. FTIR and EDS...
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A survey on network resiliency methodologies against weather-based disruptions
PublikacjaDue to the increasing dependence on network services of our society, research has recently been concentrating on enhancing traditional protection strategies to withstand large-scale failures, as in case of disaster events. The recently-formed EU-funded RECODIS project aims at coordinating and fostering research collaboration in Europe on disaster resiliency in communication networks. In particular, the Working Group (WG) 2 of the...
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Evaluation of propagation parameters of open guiding structures with the use of complex root finding algorithms
PublikacjaAn efficient complex root tracing algorithm is utilized for the investigation of electromagnetic wave propagation in open guiding structures. The dispersion characteristics of propagated and leaky waves are calculated for a couple of chosen waveguides. The efficiency of the root tracing algorithm is discuses and compared to a global root finding algorithm.
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MATCHED FILTER APPROACH FOR MICROSEISMIC SIGNAL PROCESSING OF REAL DATA FROM EAST POMERANIA SHALE GAS
PublikacjaThe microseismic monitoring is a method of monitoring of fracture propagation during hydraulic fracturing (HF)process. An array of several hundred geophones is placed on the surface to record little ground tremors induced by fracturing process. Filtration and summation of signals from geophones is essential to identify and locate fracturing events from underground. Authors propose a method of matched filtering, that is usually...
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Some Security Features of Selected IoT Platforms
PublikacjaIoT (Internet of Things) is certainly one of the leading current and future trends for processing in the current distributed world. It is changing our life and society. IoT allows new ubiquitous applications and processing, but, on the other hand, it introduces potentially serious security threats. Nowadays researchers in IoT areas should, without a doubt, consider and focus on security aspects. This paper is aimed at a high-level...
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Non-Least Square GNSS Positioning Algorithm for Densely Urbanized Areas
PublikacjaThe paper introduces an essentially new algorithm for calculating the GNSS position as an alternative to the least-square method. The proposed approach can be widely applied to any positioning method that uses multiple position lines for position calculation and is an example ofhow using a numerical solution can improve position accuracy without access to historical data. In essence, the method is based on the adaptation of the...
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Anatomy of noise in quantitative biological Raman spectroscopy
PublikacjaRaman spectroscopy is a fundamental form of molecular spectroscopy that is widely used to investigate structures and properties of molecules using their vibrational transitions. It relies on inelastic scattering of monochromatic laser light irradiating the specimen. After appropriate filtering the scattered light is dispersed onto a detector to determine the shift from the excitation wavelength, which appears in the form of...
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Nowe zakresy kreowania wizerunku fasad przy zastosowaniu technologii filtrów optycznych.
PublikacjaModern facades, whether made of glass or including transparent, translucent or reflective elements, let through a particular light spectrum or change its intensity in many different ways. “Filtering facades” may change the image seen through them or change the colour of passing light according to specific circumstances: the angle of observation or temperature. These indicated properties of facades acting as “filters” were made...