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Search results for: protokoly ieee 80211
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Non-Satellite Broadband Maritime Communications for e-Navigation Services
PublicationThe development of broadband network access technologies available to users on land has triggered a rapid expansion of a diverse range of services provided by terrestrial networks. However, due to limitations of digital communication technologies in the off-shore area, the maritime ICT systems evolution so far has not followed that trend. Despite the e-navigation initiative defining the set of Maritime Services, the progress in...
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Explicit Size-Reduction of Circularly Polarized Antennas through Constrained Optimization with Penalty Factor Adjustment
PublicationModern communication systems of high data capacity incorporate circular polarization (CP) as the preferred antenna radiation field configuration. In many applications, integration of the system circuitry with antennas imposes size limitations on CP radiators, which makes their development process a challenging endeavor. This can be mitigated by means of simulation-driven design, specifically, constrained numerical optimization....
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Simulator for Performance Evaluation of ASON/GMPLS Network
PublicationThe hierarchical control plane network architecture of Automatically Switched Optical Network with utilization of Generalized Multi-Protocol Label Switching protocols is compliant to next generation networks requirements and can supply connections with required quality of service, even with incomplete domain information. Considering connection control, connection management and network management, the controllers of this architecture...
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Reduced-Cost Microwave Design Closure by Multi-Resolution EM Simulations and Knowledge-Based Model Management
PublicationParameter adjustment through numerical optimization has become a commonplace of contemporary microwave engineering. Although circuit theory methods are ubiquitous in the development of microwave components, the initial designs obtained with such tools have to be further tuned to improve the system performance. This is particularly pertinent to miniaturized structures, where the cross-coupling effects cannot be adequately accounted...
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Reinforcement Learning Algorithm and FDTD-based Simulation Applied to Schroeder Diffuser Design Optimization
PublicationThe aim of this paper is to propose a novel approach to the algorithmic design of Schroeder acoustic diffusers employing a deep learning optimization algorithm and a fitness function based on a computer simulation of the propagation of acoustic waves. The deep learning method employed for the research is a deep policy gradient algorithm. It is used as a tool for carrying out a sequential optimization process the goal of which is...
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Design of High-Performance Scattering Metasurfaces through Optimization-Based Explicit RCS Reduction
PublicationThe recent advances in the development of coding metasurfaces created new opportunities in realization of radar cross section (RCS) reduction. Metasurfaces, composed of optimized geometries of meta-atoms arranged as periodic lattices, are devised to obtain desired electromagnetic (EM) scattering characteristics. Despite potential benefits, their rigorous design methodologies are still lacking, especially in the context of controlling...
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Mapping of the Covid-19 Vaccine Uptake Determinants From Mining Twitter Data
PublicationOpinion polls on vaccine uptake clearly show that Covid-19 vaccine hesitancy is increasing worldwide. Thus, reaching herd immunity not only depends on the efficacy of the vaccine itself, but also on overcoming this hesitancy of uptake in the population. In this study, we revealed the determinants regarding vaccination directly from people’s opinions on Twitter, based on the framework of the 6As taxonomy. Covid-19 vaccine acceptance...
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Enhancing Resilience of FSO Networks to Adverse Weather Conditions
PublicationOptical wireless networks realized by means of gigabit optical wireless communication (OWC) systems are becoming, in a variety of applications, an important alternative, or a complementary solution, to their fiber-based counterparts. However, performance of the OWC systems can be considerably degraded in periods of unfavorable weather conditions, such as heavy fog, which temporarily reduce the effective capacity of the network....
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Design of a compact planar transmission line for miniaturized rat-race coupler with harmonics suppression
PublicationThis paper presents an elegant yet straightforward design procedure for a compact rat-race coupler (RRC) with an extended harmonic suppression. The coupler’s conventional λ/4 transmission lines (TLs) are replaced by a specialized TL that offers significant size reduction and harmonic elimination capabilities in the proposed approach. The design procedure is verified through the theoretical, circuit, and electromagnetic (EM) analyses,...
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Modelling and Control of a Brushless Multiphase Doubly-Fed Induction Generator in a Stand-Alone Wind Generation System
PublicationThe development of the novel multiphase brushless doubly-fed generator system and voltage controller for stand-alone mode configuration is proposed in this paper. The generator system is based on the new machine construction with multiphase control winding and traditional three-phase power winding. The dynamic model of multiphase brushless doubly-fed generator is presented, and the control strategy for voltage amplitude and frequency...
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Single-Phase 15-Level Switched-Capacitor Boost Multilevel Inverter Topology for Renewable Energy Applications
PublicationGalvanic isolation is a vital part of a grid-connected solar PV system. With the growth of multilevel inverters for grid-connected applications, the multilevel inverters having isolation are not sufficiently discussed in the literature. In this paper, a 15-level isolated multilevel inverter topology requiring only thirteen switches is proposed. The envisaged configuration includes two cells, designated as upper and lower cells....
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Low-cost multiband four-port phased array antenna for sub-6 GHz 5G applications with enhanced gain methodology in Radio-over-fiber systems using modulation instability
PublicationPhased array antenna (PAA) technology is essential for applications requiring high gain and wide bandwidth, such as sensors, medical, and 5G. Achieving such a design, however, is a challenging and intricate process that calls for precise calculations and a combination of findings to alter the phase and amplitude of each unit. Furthermore, coupling effects between these PAA structure elements can only be completed with the use of...
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Concurrent Video Denoising and Deblurring for Dynamic Scenes
PublicationDynamic scene video deblurring is a challenging task due to the spatially variant blur inflicted by independently moving objects and camera shakes. Recent deep learning works bypass the ill-posedness of explicitly deriving the blur kernel by learning pixel-to-pixel mappings, which is commonly enhanced by larger region awareness. This is a difficult yet simplified scenario because noise is neglected when it is omnipresent in a wide...
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Evaluation of Connectivity Gaps Impact on TCP Transmissions in Maritime Communications
PublicationMany organizations and research working groups, including among others IEEE, ITU, ETSI and IMO are currently working towards improvements in communication of different types of vehicles (cars, trains, planes and vessels) and upgrading utilities and services offered to their crews and passengers travelling all over the world. The paper deals with selected aspects of the TCP protocol connectivity in maritime wireless networks. The...
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Propozycja optymalizacji wyboru interfejsu bezprzewodowego w heterogenicznej sieci dostępowej
PublicationSzybki rozwój sieci bezprzewodowych oraz ich szeroka dostępność sprawiają, iż ich użytkownicy coraz częściej znajdują ię w obszarze działania kilku róznych bezprzewodowych systemów zapewniajacych dostęp do zasobów internetu. Środowisko takie nazywamy heterogenicznym. Integruje ono bowiem zróżnicowane technologicznie sieci w tym najczęściej rozwiązania standardu IEEE.*02.11 oraz sieci komórkowe zarówno 3G, jak 4G, ale także4 systemy...
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Efektywne kształtowanie widma radiowego sygnału impulsowego (IR UWB) dla potrzeb wymagań międzysystemowej kompatybilności elektromagnetycznej
PublicationW części wstępnej zawarto opis uwarunkowań prawnych i normalizacyjnych dotyczących transmisji ultraszerokopasmowych, opisana jest także ultraszerokopasmowa technika radia impulsowego. Następnie przedstawiono znane w literaturze sposoby wpływania na kształt widma transmisji impulsowych, zarówno przez dobór nadawanych impulsów jak i zmiany w strukturze czasowej nadawanej sekwencji. Główną część pracy stanowi opis proponowanych nowych...
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Separation of the effects of notch and macro residual stress on the MFL signal characteristics
PublicationMagnetic flux leakage (MFL) distribution for three configurations of samples has been investigated in order to study the influence of notch and plastic deformation separately as well as together. Samples have been made of S355 steel. The MFL signal measurements were carried out along the longest dimension of the sample over a length of 120 mm. Two components of magnetic field were measured: 1) tangential to the main axis and 2)...
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Influence of plastic deformation on stray magnetic field distribution of soft magnetic steel sample
PublicationThe effect of various combinations of conditions, i.e., presence of the Earth’s magnetic field during and after deformation on the distribution of stray magnetic field of S355 steel sample, which is locally deformed, was investigated. Some of the stages of the experiment were carried out in zero magnetic field. Compensation of the Earth’s magnetic field was obtained by the application of a pair of Helmholtz coils. These coils are...
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ICUMT 2011 Congress in Budapest, Hungary
Publicationartykuł sprawozdawczy z konferencji
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3rd International Workshop on Reliable Networks Design and Modeling (RNDM 2011)
Publicationartykuł sprawozdawczy z konferencji
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Low Current Transformer Utilizing Co-Based Amorphous Alloys
PublicationMetal oxide surge arresters have been widely used for protection of power system networks against overvoltages due to atmospheric discharges or malfunction of devices connected to the network. During its operation a surge arrester structure is degradated, what can be observed as an increase of a surge arrester leakage current. Paper presents an implementation of a new, high-permeability, Co64Fe4Ni1Si15B14 amorphous alloy as a current...
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Low current transformer utilizing Co-based amorphous alloys
PublicationMetal oxide surge arresters have been widely used for protection of power system networks against overvoltages due to atmospheric discharges or malfunction of devices connected to the network. During its operation a surge arrester structure is degradated, what can be observed as an increase of a surge arrester leakage current. Paper presents an implementation of a new, high-permeability, Co64Fe4Ni1Si15B14 amorphous alloy as a current...
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Assessment with mechanical Barkhausen effect of residual stress in grain oriented polycrystalline 3% Si-Fe sheet
PublicationW tym artykule zostały opisane badania naprężeń resztkowych w blachach wykonanych z 3% si-fe o zorientowanym ziarnie za pomocą mechanicznego efektu barkhausena (mebn). badano blachy o 3 różnych orientacjach ziaren względem głównej osi próbki: 0, 45, 90 stopni. badania mebn przeprowadzano wzbudzając drgania skrętne oraz drgania gięte. zmierzone maksima obwiedni napięcia skutecznego mebn znajdują się dla badanych próbek w regionie...
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Comments on "Decomposition of Permutation Networks"
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An Approximation Algorithm for Diagnostic Test Scheduling in Multicomputer Systems
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Fluctuation-Enhanced Sensing for Biological Agent Detection and Identification
PublicationPrzedstawiono wcześniejsze wyniki badań dotyczące trzech różnych sposobów wykrywania obecności substancji biologicznych za pomocą zjawisk fluktuacyjnych: 1) wirusów wnikających do komórek, 2) zapachów emitowanych przez mikroby, 3) rozkładu widma i wartości chwilowych szumów podczas rozpraszania światła używanego do wykrywania zarodników na podstawie wyznaczenia współczynnika dyfuzji opisująceo ich ruch.We survey and show our earlier...
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Possibility of Application of Magnetoacoustic Emission for the Assessment of Plastic Deformation Level in Ferrous Materials
PublicationArtykuł prezentuje wyniki badań dotyczących możliwości zastosowana emisji magnetoakustycznej (EMA) do nieniszczącej oceny stopnia deformacji plastycznej próbek poddanych jednoosiowemu rozciąganiu. Przebadane zostały cztery różne materiały: stale 13HMF, CSN12021 i P91 oraz żelazo Armco. Badania pokazały, że różne parametry magnetyczne i magnetoakustyczne badanych materiałów mogą zmieniać się w rożny sposób, jednakże zawsze obserwuje...
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Impact of Tensile and Compressive Stress on Classical and Acoustic Barkhausen Effects in Grain-Oriented Electrical Steel
PublicationIn this paper, we present the results of the investigation of impact of tensile and compressive stress on the classical Barkhausen effect, magnetoacoustic emission (MAE) signal properties, and B(H) hysteresis loops for grain-oriented (GO) electrical steel. Samples have been glued to a nonmagnetic steel bar and stressed within elastic range (±800 μdef) by means of four-point bending method. The samples were cut out in two directions...
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Fourth International Workshop on Reliable Networks Design and Modeling (RNDM 2012)
Publicationartykuł sprawozdawczy z konferencji
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Determination of Complex Permeability of Silicon Steel for Use in High-Frequency Modeling of Power Transformers
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Computer simulation of induction hardening of moving flat charge
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k-Penalty: A Novel Approach to Find k-Disjoint Paths with Differentiated Path Costs
PublicationW artykule rozpatrywany jest problem ochrony dedykowanej na wypadek awarii wielokrotnej elementów sieci teleinformatycznej. Wspomniana ochrona jest możliwa do zapewnienia poprzez wyznaczenie i zainstalowanie zbioru k rozłącznych ścieżek dla każdego żądania. W szczególności rozpatrywany jest problem wyznaczenia k rozłącznych ścieżek w sieciach typu ''multi-cost'', w przypadku których koszt dowolnego łącza może być różny dla każdej...
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Comments on ''an SVD-based watermarking scheme for protecting rightful ownership''
PublicationW pracy wykazano, że algorytm zaproponowany w komentowanym artykule nie ma wartości praktycznej, gdyż charakteryzuje się bardzo dużym prawdopodobieństwem fałszywej akceptacji.
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Advanced Agent Identification With Fluctuation-Enhanced Sensing
PublicationPraca przedstawia wyniki szeregu zaawansowanych algorytmów przetwarzania sygnałów losowych obserwowanych w sensorach gazu typu Taguchi Gas Sensors. Stwierdzono, że proponowane metody pozwalają wykrywać bardziej efektywnie obecność wielu różnych gazów. W celu detekcji zastosowano głównie funkcje spektrum i bispektrum.
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An ultrasonic obstacle detector based on phase beamforming principles
PublicationW artykule przedstawiono rezultaty prac nad ultradźwiękowym wykrywaczem przeszkód dla niewidomych. Opisano metodę lokalizacji przeszkód w oparciu o algorytm beamformingu fazowego. Zaprezentowano rezultaty badań przeprowadzonych nad prototypem urządzenia.
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Comparison of properties of magnetoacoustic emission and mechanical Barkhausen effects for P91 steel after plastic flow and creep
PublicationW artykule przedstawiono wyniki pogłębionej analizy sygnału szumowego efektu Barkhausena dla próbek ze stali krzemowej Fe-2%Si po deformacji plastycznej. Badane były próbki po walcowaniu na zimno powodującym odkształcenie względne w zakresie do 8%. Pierwsze podejście polegało na analizie w dziedzinie czasu widma badanego sygnału. Analiza ta została uzupełniona o analizę liczby zliczeń impulsów w funkcji napięcia progowego, zarówno...
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Modeling of effect of plastic deformation on Barkhausen noise and magnetoacoustic emission in iron with 2% silicon
PublicationW modelowaniu zaadaptowano model Alessandro-Beatrice-Bertotti-Montorsi dla opisu ruchu granic nie-180 stopniowych oraz model Jiles-Atherton dla opisu wpływu plastycznej deformacji na natężenie efektu Barkhausena oraz emisji magnetoakustcznej.
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An in-depth study of the Barkhausen emission signal properties of the plastically deformed Fe-2%Si alloy
PublicationZbadana została korelacja między natężeniem emisji magnetoakustycznej a natężeniem mechanicznego efektu Barkhausena dla próbek ze stali P91 mających różną mikrostrukturę na skutek plastycznego płynięcia w temperaturze pokojowej lub na skutek przyspieszonego pełzania w temperaturze 773K pod naprężeniem 290 KPa. Zakres deformacji plastycznej dla pierwszego zestawu próbek wynosił od 2% do 10,5% a dla drugiego od 0,85% do 10%. Oba...
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How to render FDTD computations more effective using agraphics accelerator.
PublicationGraphics processing units (GPUs) for years have been dedicated mostly to real time rendering. Recently leading GPU manufactures have extended their research area and decided to support also graphics computing. In this paper, we describe an impact of new GPU features on development process of an efficient finite difference time domain (FDTD) implementation.
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Adaptive CAD-Model Construction Schemes
PublicationTwo advanced surrogate model construction techniques are discussed in this paper. The models employ radial basis function (RBF)interpolation scheme or artificial neural networks (ANN) with a new training algorithm. Adaptive sampling technique is applied withrespect to all variables. Histograms showing the quality of the models are presented. While the quality of RBF models is satisfactory, theperformance of the ANN models obtained...
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Evaluation of Barkhausen Noise and Magnetoacoustic Emission Signals Properties for Plastically Deformed Armco Iron
PublicationArtykuł prezentuje wyniki badania wpływu różnych rodzajów deformacji plastycznej na właściwości magnetoakustyczne żelaza Armco. Badane były dwie serie próbek - pierwsza składała się ze wstępnie wyżarzonych próbek, które następnie były walcowane na zimno, w skład drugiej wchodziły natomiast próbki wycięte z komercyjnie dostępnej blachy wykonanej z żelaza Armco a następnie poddane obciążeniom rozciągającym. Walcowanie na zimno prowadzi...
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Barkhausen noise properties measured by different methods for deformed Armco samples
PublicationPorównano właściwości sygnału napięciowego efektu Barkhausena (BN) uzyskanego za pomocą 'sondy punktowej' (użytecznej dla badań przemysłowych) oraz cewki otaczającej badany materiał. W pierwszej metodzie mierzono trzy wielkości: V1 - napięcie skuteczne, Nc - liczba impulsów, V2 - napięcie kontrolne z cewki. W drugiej metodzie z napięcia indukowanego w cewce wyznaczano pętlę histerezy B(H), obwiednie z napięcia skutecznego a także...
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Automatic cuts for magnetic scalar potential formulations
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High-Frequency Proximity Losses Determination for Rectangular Cross-Section Conductors
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Identification of Cellular Automata Based on Incomplete Observations With Bounded Time Gaps
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Comparative Study of Taste Substance Sensing by Liquid Membrane Oscillator and Electrochemical Systems With All-Solid-State Electrodes
PublicationIn food industry, different types of sensors are used for characterizing and quantifying taste substances. Therefore, it is important to establish the principal advantages and disadvantages of these sensors for optimal application. In this paper, two possible systems are compared for sensing the four fundamental tastes: sour (citric acid), salty (sodium chloride), sweet (sucrose), and bitter (caffeine or quinine hydrochloride). One...
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Practical Evaluation of Internet Systems' Security Mechanisms
PublicationA proposed Internet systems security layer with context-oriented security mechanisms reduces the risk associated with possible vulnerabilities. A metric of the system trust level is proposed, and then evaluated according to a university Internet system.
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Qualitative and Quantitative Analysis of Selected Tonic Waters by Potentiometric Taste Sensor With All-Solid-State Electrodes
PublicationTaste sensor with five all-solid-state electrodes (ASSE) III (third version) was used for qualitative and quantitative analysis of selected tonic waters (J.Gasco, Kinley, Jurajski, Jurajski with citrus flavor, Carrefour, Schweppes Indian Tonic, and Schweppes Bitter Lemon). The results obtained by this taste sensor analyzed with principal component analysis, agglomerative hierarchical clustering methods show that this sensor can...
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Credibility of Threats to Jam Anonymous Traffic Remapping Attacks in Ad Hoc WLANs
PublicationIn ad hoc networks, selfish stations can pursue a better quality of service (QoS) by performing traffic remapping attacks (TRAs), i.e., by falsely assigning their traffic to a higher priority class, which can hurt honest stations’ QoS. To discourage the attackers, honest stations can announce their dissatisfaction with the perceived QoS. If such a threat fails, a costly data frame jamming defense can be launched. We analyze the...
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RNDM 2016 Workshop and 2nd Meeting of COST CA15127-RECODIS: Highlights from the Resilience Week in Halmstad, Sweden
PublicationLeading network resilience researchers took part in the Resilience Week on Sept. 12-15, 2016 at Halmstad University, SE by Prof. Magnus Jonsson from the Centre for Research on Embedded Systems (CERES), Halmstad University, SE, and Prof. Jacek Rak from Gdansk University of Technology, PL. It included two major events: - The 2nd Meeting of COST CA15127–RECODIS Action (Resilient Communication Services Protecting End-user Applications...