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Search results for: recofigurable anenna
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Rapid design of miniaturised branch-line couplers through concurrent cell optimisation and surrogate-assisted fine-tuning
PublicationIn this study, the authors introduce a methodology for low-cost simulation-driven design optimisation of highly miniaturised branch-line couplers (BLCs). The first stage of their design approach exploits fast concurrent optimisation of geometrically dependent, but electromagnetically isolated cells that constitute a BLC. The cross-coupling effects between the cells are taken into account in the second stage, where a surrogate-assisted...
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Scattering From a Cylindrical Object of Arbitrary Cross Section With the Use of Field Matching Method
PublicationA simple and intuitive solution to scattering problems in shielded and open structures is presented. The main idea of the analysis is based on the direct field matching technique involving the usage of projection of the fields at the boundary on a fixed set of orthogonal basis functions. Different convex shapes and various obstacle materials are considered to verify the validity of the method in open and closed structures. The...
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Efficient Complex Root Tracing Algorithm for Propagation and Radiation Problems
PublicationAn efficient complex root tracing algorithm for propagation and radiation problems is presented. The proposed approach is based on a discretization of Cauchy’s Argument Principle and its generalization to the C × R space. Moreover, an engagement of the tracing process with a global root finding algorithm recently presented in the literature is performed. In order to confirm a validity and efficiency of the proposed technique, a...
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An Off-Body Channel Model for Body Area Networks in Indoor Environments
PublicationThis paper presents an off-body channel model for body area networks (BANs) in indoor environments. The proposed model, which is based on both simulations and measurements in a realistic environment, consists of three components: mean path loss, body shadowing, and multipath fading. Seven scenarios in a realistic indoor office environment containing typical scatterers have been measured: five were static (three standing and two...
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Rapid multi-objective design optimisation of compact microwave couplers by means of physics-based surrogates
PublicationThe authors introduce a methodology for fast multi-objective design optimisation of miniaturised microwave couplers. The approach exploits the surrogate-based optimisation paradigm with an underlying low-fidelity model constructed from an equivalent circuit of the structure under consideration, corrected through implicit and frequency space mapping. A fast prediction tool obtained this way is subsequently optimised by a multi-objective...
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Rapid simulation-driven design of miniaturised dual-band microwave couplers by means of adaptive response scaling
PublicationOne of the major challenges in the design of compact microwave structures is the necessity of simultaneous handling of several objectives and the fact that expensive electromagnetic (EM) analysis is required for their reliable evaluation. Design of multi-band circuits where performance requirements are to be satisfied for several frequencies at the same time is even more difficult. In this work, a computationally efficient design...
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Analytical Expression for the Time-Domain Green's Function of a Discrete Plane Wave Propagating in the 3-D FDTD Grid
PublicationIn this paper, a closed-form expression for the time-domain dyadic Green’s function of a discrete plane wave (DPW) propagating in a 3-D finite-difference time-domain (FDTD) grid is derived. In order to verify our findings, the time-domain implementation of the DPW-injection technique is developed with the use of the derived expression for 3-D total-field/scattered-field (TFSF) FDTD simulations. This implementation requires computations...
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Bandwidth-size design trade-offs for compact spline-parameterised patch couplers by means of electromagnetic-driven multi-objective optimisation
PublicationBroad bandwidth and small size are the key performance figures for contemporary microwave couplers. These requirements are conflicting, i.e. improvement of one generally leads to degradation of the other assuming fixed topology of the circuit at hand. From a designer's perspective, the knowledge about available design trade-offs is indispensable as it permits for tailoring the circuit for particular applications as well as comparing...
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Variable-fidelity response feature surrogates for accelerated statistical analysis and yield estimation of compact microwave components
PublicationAccounting for manufacturing tolerances is an essential part of a reliable microwave design process. Yet, quantification of geometry and/or material parameter uncertainties is challenging at the level of full-wave electromagnetic (EM) simulation models. This is due to inherently high cost of EM analysis and massive simulations necessary to conduct the statistical analysis. Here, a low-cost and accurate yield estimation procedure...
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Communication Model Order Reduction in Hybrid Methods Involving Generalized Impedance Matrix
PublicationA novel strategy for the efficient analysis of frequency-domain scattering electromagnetic problems in open and closed domains is presented. A fully automatic model-order reduction technique, called the enhanced reduced-basis method, is applied to increase the efficiency of the hybrid approach, which combines the finite-element and mode-matching methods. Numerical tests show that the proposed algorithm yields reliable and highly...
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Low-cost data-driven modelling of microwave components using domain confinement and PCA-based dimensionality reduction
PublicationFast data-driven surrogate models can be employed as replacements of computationally demanding full-wave electromagnetic simulations to facilitate the microwave design procedures. Unfortunately, practical application of surrogate modelling is often hindered by the curse of dimensionality and/or considerable nonlinearity of the component characteristics. This paper proposes a simple yet reliable approach to cost-efficient modelling...
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A Self-Adaptive Complex Root Tracing Algorithm for the Analysis of Propagation and Radiation Problem
PublicationAn improved complex root tracing algorithm for radiation and propagation issues is proposed. The approach is based on a self-adaptive discretization of Cauchy’s argument principle for a C × R space and requires a reduced number of function calls in comparison to other procedures presented in the literature. A few different examples concerning propagation and radiation problems have been considered to verify the validity and efficiency...
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An Off-Body Narrowband and Ultra-Wide Band Channel Model for Body Area Networks in a Ferry Environment
PublicationIn the article an off-body narrowband and ultra-wide band channel model for Body Area Networks in a ferry environment is described. A mobile, heterogeneous measurement stand, that consists of three types of devices: miniaturized mobile nodes, stationary reference nodes and a data acquisition server was developed. A detailed analysis of both radio channels parameters in untypical indoor environment was carried out. An analysis of...
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Progress in the post weld residual stress evaluation using Barkhausen effect meter with a novel rotating magnetic field probe
PublicationWe report the progress in post weld residual stress evaluation using Barkhausen effect (BE) meter with rotating magnetic field probe. The novel probe of the BE meter contains two C-core electromagnets and searching coil with ferrite antenna. This meter allows automatic measurements of BE intensity envelopes at different angles of magnetizing field. The full process of measurement at given position of the probe takes about only...
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Laboratory investigation with subbottom parametric echosounder SES-2000 standard with an emphasis on reflected pure signals analysis
PublicationThe main goal of the paper is to describe correlations between measurements results of trials taken on Gulf of Gdańsk bottom sounded with parametric echosounder SES-2000 Standard and laboratory research where collected during survey sediments were measured. Stationary tests took place at Gdansk University of Technology where 30 meters long 1.8 meter deep and 3 meters wide water tank is located. Main lobe of antenna was directed...
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High precision and accuracy using low cost GNSS receivers and supporting technologies
PublicationThis chapter focuses on methods and techniques of positioning, based on the highly accurate and precise Global Navigation Satellite System (GNSS), which are available at a relatively low price. In this context, a comparison of different positioning methods provided by the free and open source software (FOSS) package called RTKLIB is given. Other aspects related to price reduction are also considered, including availability and...
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Visible-light-driven lanthanide-organic-frameworks modified TiO2 photocatalysts utilizing up-conversion effect
PublicationHighly efficient and quite stable composite with core-shell-like architecture reported herein, responds to the challenge of sunlight-driven photocatalysts. The Ln(ndc)/TiO2 photocatalytic system comprises active lanthanide-carboxylate coordination networks (Nd, Er, Ho, and Tm as metal ions, and 2,6-naphthalene dicar-boxylic acid as the organic linker) and inert titanium dioxide and allow to convert incompatible visible radiation...
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Zero-Pole Approach in Microwave Passive Circuit Design
PublicationIn this thesis, optimization strategies for design of microwave passive structures including filters, couplers, antenna and impedance transformer and construction of various surroogate models utilized to fasten the design proces have been discussed. Direct and hybrid optimization methodologies including space mapping and multilevel algorithms combined with various surrogate models at different levels of fidelity have been utilized...
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Badanie i analiza efektywności alokacji strumieni danych w heterogenicznej sieci WBAN
PublicationW niniejszej dysertacji doktorskiej poddano dyskusji efektywność alokacji strumieni danych w heterogenicznej radiowej sieci WBAN (Wireless Body Area Networks). Biorąc pod uwagę dynamiczny rozwój nowoczesnych sieci radiokomunikacyjnych piątej generacji (5G), którego część stanowią radiowe sieci działające w obrębie ciała człowieka, bardzo ważnym aspektem są metody maksymalizujące wykorzystanie dostępnych zasobów czasowo –częstotliwościowych...
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Zmodyfikowana metoda monopulsowa w wielowiązkowych filtrach przestrzennych sonarów pasywnycj
PublicationZwiększenie dokładności określania namiaru celu można uzyskać w sonarach stosując metodę monopulsową. W konwencjonalnych sonarach polega ona na wyrównywaniu sygnałów w dwóch sąsiednich wiązkach poprzez obrót anteny. W cyfrowych sonarach wielowiązkowych obrót anteny można zastąpić obliczeniami, które przedstawiono w referacie. Opracowaną metodę poprawy dokładności namiaru pokazano na przykładzie szerokopasmowego sonaru wielowiązkowego...
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A ship domain-based model of collision risk for near-miss detection and Collision Alert Systems
PublicationThe paper presents a new model of ship collision risk, which utilises a ship domain concept and the related domain-based collision risk parameters. An encounter is here described by five variables representing: degree of domain violation (DDV), relative speed of the two vessels, combination of the vessels’ courses, arena violations and encounter complexity. As for the first three variables, their values can be directly computed...
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Rola inicjatyw społecznych w ochronie dziedzictwa kulturowego na przykładzie mozaiki Anny Fiszer na ścianie kina Neptun w Gdańsku
PublicationStreszczenie: Rola inicjatyw społecznych w ochronie dziedzictwa kulturowego na przykładzie mozaiki Anny Fiszer na ścianie kina Neptun w Gdańsku. Celem artykułu jest wykazanie roli inicjatyw społecznych w budzeniu poczucia odpowiedzialności za dziedzictwo materialne i kulturowe. Przyjęto założenie, że dla lokalnych społeczności miasto jest przestrzenią pamięci. Nastrój, atmosfera i klimat miejsca to słowa, które określają fizyczny...
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Definicje ontologii w wieloagentowym systemie do oceny technologii informatycznych
PublicationCelem artykułu jest zdefiniowanie ontologii dla potrzeb systemu wieloagentowego do oceny technologii informatycznych. Definicje ontologii stanowią podstawę do przygotowania ich specyfikacji dla potrzeb JADE (Java Agent Development Framework). W założeniu ma to być rozwiązanie wieloagentowe korzystające z takich elementów jak bazy wiedzy oraz ontologie traktowane z punktu widzenia JADE jako dołączane biblioteki. W artykule zaprezentowano...
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Drawing maps with advice
PublicationRozważamy następujący problem obliczeniowy. Agent zostaje umieszczony w wierzchołku nieznanego mu grafu. Wierzchołki grafu są nierozróżnialne, natomiast krawędzie posiadają numery portów. Zadaniem agenta jest wyznaczenie mapy, tzn. obliczenie izomorficznej kopii grafu, lub obliczenie dowolnego drzewa spinającego grafu. Bez dodatkowej informacji zadań tych nie można wykonać. W artykule wyznaczamy oszacowania na minimalną liczbę...
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Methodological challenges in social entrepreneurship – on the nexus of economics and management area
PublicationIn this paper we make an attempt distinguishing challenges in SE research agenda in Polish and beyond. We identify what can impede the development of this area in Polish discourse These challenges vary in scope. They involve the dilemma between either economics or management as disciplinary settings. Also the understanding of social economy as such determines the chaos. Additionally, divergences in paradigms where researchers situate...
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Framing the Temporal Dimensions of a Brand
PublicationDrawing on existing research dealing with time in brand and brand management, this paper aims at providing a comprehensive and coherent framework of some time-related concepts, with a special emphasis on what happens when a brand reaches the senescence stage. In addition, it strives to consider what happens when a brand becomes long-lived enough, looking at the brand’s customer base. While undoubtedly time affects customers’ age...
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On the Importance of Resilience Engineering for Networked Systems in a Changing World
PublicationResilience is featured increasingly often in the media, usually applied to society when faced, for example, with disasters such as flooding and the enormous challenges that the Covid-19 pandemic posed. There are now many resilience-related discussion groups worldwide, and some standards initiatives devoted in particular to city resilience. However, there is relatively little explicit interest in resilience engineering for communication...
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A Novel Trust-Region-Based Algorithm with Flexible Jacobian Updates for Expedited Optimization of High-Frequency Structures
PublicationSimulation-driven design closure is mandatory in the design of contemporary high-frequency components. It aims at improving the selected performance figures through adjustment of the structure’s geometry (and/or material) parameters. The computational cost of this process when employing numerical optimization is often prohibitively high, which is a strong motivation for the development of more efficient methods. This is especially...
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An automated, low-latency environment for studying the neural basis of behavior in freely moving rats
PublicationBackground Behavior consists of the interaction between an organism and its environment, and is controlled by the brain. Brain activity varies at sub-second time scales, but behavioral measures are usually coarse (often consisting of only binary trial outcomes). Results To overcome this mismatch, we developed the Rat Interactive Foraging Facility (RIFF): a programmable interactive arena for freely moving rats with multiple feeding...
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Szyk planarny anten mikropasokwych z przeznaczeniem do radaru dopplerowskiego
PublicationW pracy opisano konstrukcję oraz wyniki pomiarów szyku 4 anten mikropaskowych w postaci macierzy 2x2, zaprojektowanych na częstotliwość 10 GHz. Pojedynczym promiennikiem w szyku jest antena mikropaskowa , zasilana przez sprzężenie elektromagnetyczne realizowane przez szczelinę we wspólnym ekranie. W wyniku badań zrealizowanych 3 egzemplarzy szyku stwierdzono, że niewielkie odchyłki w wymiarach fizycznych badanych układów przełożyły...
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Characterization of slow and fast fading in off-body communication at 2.45 GHz with space diversity scheme in indoor environment
PublicationThe characterization of slow and fast fading in Wireless Body Area Networks with space diversity scheme has been presented. The analysis, based on the measurements at 2.45 GHz in indoor environment, has shown that for all investigated configurations of receiving wearable antennas the correlation coefficient values of received signals’ parameters are below the assumed value of 0.5, being close to zero for the vast majority of cases. It...
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Badania i analiza uwarunkowań propagacyjnych w środowisku uprzemysłowionym
PublicationGłówne osiągnięcia rozprawy: - wykonanie – zgodnie z wymaganiami normatywnymi zawartymi w zaleceniach ITU-R – nowatorskich badań tłumienia sygnału radiowego na terenie Głębokowodnego Terminalu Kontenerowego (ang. Deepwater Container Terminal - DCT) w Gdańsku i zebranie obszernego materiału pomiarowego, liczącego blisko 290 tysięcy przypadków propagacyjnych, - przeprowadzenie statystycznych badań przydatności wybranych znanych modeli...
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Usage of parametric echosounder with emphasis on buried object searching.
PublicationThe purpose of this article is to present the results of investigation to search for buried objects. The paper will contain echograms and other means of visualization from buried pipe placed between area of W?adys?awowo and gas platform and interesting in terms of the number of small and medium-sized unidentified objects found in the muddy bottom at different depths localized in the Gulf of Puck - results will be presented also...
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Wytwarzanie i charakterystyka cienkich warstw diamentowych na podłożach ze szkła kwarcowego, w szczególności na światłowodach włóknistych, dla zastosowań w sensorach optoelektronicznych
PublicationGłównym celem naukowym prac badawczych przeprowadzonych w rozprawie było wytwarzanie i modyfikacja funkcjonalności cienkich, przewodzących warstw diamentowych syntezowanych na podłożach optycznych. W ramach przeprowadzonych badań wytworzono szereg warstw diamentowych o specyficznych właściwościach optycznych i elektrycznych, mających na celu wykazanie możliwości wykorzystania takich struktur dla celów sensorycznych. Do poprawy...
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Volumetric incorporation of NV diamond emitters in nanostructured F2 glass magneto-optical fiber probes
PublicationIntegration of optically-active diamond particles with glass fibers is a powerful method of scaling diamond's magnetic sensing functionality. We propose a novel approach for the integration of diamond particles containing nitrogen-vacancy centers directly into the fiber core. The core is fabricated by stacking the preform from 790 soft glass canes, drawn from a single rod dip-coated with submicron diamond particles suspended in...
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Application of spectroscopy to the measurement of blood parameters
PublicationSpectroscopy is the study of formation and interpretation of the spectra arising from the interactions of all types of radiation on matter, understood as a collection of atoms and molecules. This is a very important department of optics which gives us many opportunities to measure various parameters such as material blood parameters. Among the diseases that are associated significantly with changes in rheological properties of...
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System wieloagentowy wspomagający projektowanie wybranych układów sterowania okrętowych podsystemów elektroenergetycznych
PublicationW rozprawie doktorskiej zaproponowano system wieloagentowy do wspomagania projektowana okrętowych podsystemów elektroenergetycznych. Utworzony system składa się z agentów interfejsu, agenta nadrzędnego, agentów symulacyjnych agentów decyzyjnych, które poprzez realizację wewnętrznych algorytmów oraz wzajemną komunikację rozwiązują wybrane zadania projektowe w zakresie doboru odpowiedniej struktury i elementów składowych podsystemów...
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MONITORING KONSTRUKCJI Z ZASTOSOWANIEM NIWELACJI HYDROSTATYCZNEJ
PublicationCelem artykułu jest przedstawienie zastosowania różnych typów systemów niwelacji hydrostatycznej. Systemy te stanowią główny moduł pomiarowy urządzeń służących do ciągłej diagnostyki obiektów budowlanych, całych dzielnic lub wielkogabarytowych urządzeń. Zaletą systemów hydrostatycznych jest ich duża dokładność, niezawodność i relatywnie niska cena. W pracy przedstawione zostały zastosowania zautomatyzowanych modułów niwelacji hydrostatycznej...
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Recent and Emerging Applications of Graphene-based metamaterials in Electromagnetics
PublicationSurface Plasmon Polaritons (SPPs) operating in mid-infrared up to terahertz (THz) frequencies have been traditionally manufactured on expensive metals such as gold, silver, etc. However, such metals have poor surface confinement that limits the optical applications of SPPs. The invention of graphene is a breakthrough in plasmon-based devices in terms of design, fabrication and applications, thanks to its plasmonic wave distribution,...
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DICTOBOT - autonomiczny agent ze zdolnością komunikacji
PublicationNiniejszy artykuł zdaje sprawę z opracowanego sposobu budowy autonomicznego agenta komunikującego się z otoczeniem w sposób werbalny. Agent taki, opierający się na formalnym, matematycznym modelu psychologii osobowości człowieka, w zależności od stanu emocjonalnego, w jakim się znajduje, w odpowiedni sposób interpretuje usłyszane kwestie oraz formułuje swoją wypowiedź. Jednocześnie, w zależności od stopnia spełnienia swoich potrzeb,...
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The impact of technological and structural changes in the national economy on the labour-capital relations
PublicationThe aim of the research presented in this paper is to present the relations between labour and capital in the national economy, resulting from technological and structural changes taking place in the years 1991 to 2008. The structure of the paper is as follows. It first presents the functional determinants for the Polish economy in 1991-2008 affecting the phenomenon subject to study. Then it presents the preliminary analysis of...
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Vibration monitoring of structures in the light of the Polish and international requirements
PublicationThe paper concerns the wide range of strategies used to protect structures against man-made dynamic excitation. The most popular approaches applied worldwide are compared, and the main differences and similarities are summarized. The literature studies are supported by the results of the measurements performed on different types of real structures, which are sensitive and insensitive to the dynamic load. To make the conclusions...
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Muzyka jako element twórczy w architekturze na podstawie teorii B. Leitnera.
PublicationMuzyka pozostaje w głębokiej relacji z innymi dziedzinami w tym w szczególności z architekturą. Treść artykułu przedstawia praktyczne wykorzystanie nietypowego dla kształtowania przestrzeni medium - dźwięku w procesie projektowym. Wykorzystanie muzyki (dźwięku) daje możliwość swobodnego kreowania przestrzeni między innymi zmiany funkcji, formy zewnętrznej, kształtowania komunikacji. Ujęta problematyka może być cenna również dla...
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A new approach to design of weather disruption-tolerant wireless mesh networks
PublicationWireless Mesh Networks, offering transmission rates of 1–10 Gb/s per a millimeter-wave link (utilizing the 71–86 GHz band) seem to be a promising alternative to fiber optic backbone metropolitan area networks because of significantly lower costs of deployment and maintenance. However, despite providing high transmission rates in good weather conditions, high-frequency wireless links are very susceptible to weather disruptions....
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The Proposal to “Snapshot” Raim Method for Gnss Vessel Receivers Working in Poor Space Segment Geometry
PublicationNowadays, we can observe an increase in research on the use of small unmanned autonomous vessel (SUAV) to patrol and guiding critical areas including harbours. The proposal to “snapshot” RAIM (Receiver Autonomous Integrity Monitoring) method for GNSS receivers mounted on SUAV operating in poor space segment geometry is presented in the paper. Existing “snapshot” RAIM methods and algorithms which are used in practical applications...
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Performance-driven yield optimization of high-frequency structures by kriging surrogates
PublicationUncertainty quantification is an important aspect of engineering design, as manufacturing toler-ances may affect the characteristics of the structure. Therefore, quantification of these effects is in-dispensable for adequate assessment of the design quality. Toward this end, statistical analysis is performed, for reliability reasons, using full-wave electromagnetic (EM) simulations. Still, the computational expenditures associated...
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Data-Driven Surrogate-Assisted Optimization of Metamaterial-Based Filtenna Using Deep Learning
PublicationIn this work, a computationally efficient method based on data driven surrogate models is pro-posed for the design optimization procedure of a Frequency Selective Surface (FSS)-based filtering antenna (Filtenna). A Filtenna acts as a as module that simultaneously pre-filters unwanted sig-nals, and enhances the desired signals at the operating frequency. However, due to a typically large number of design variables of FSS unit elements,...
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Block Conjugate Gradient Method with Multilevel Preconditioning and GPU Acceleration for FEM Problems in Electromagnetics
PublicationIn this paper a GPU-accelerated block conjugate gradient solver with multilevel preconditioning is presented for solving large system of sparse equations with multiple right hand-sides (RHSs) which arise in the finite-element analysis of electromagnetic problems. We demonstrate that blocking reduces the time to solution significantly and allows for better utilization of the computing power of GPUs, especially when the system matrix...
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Implicit Space Mapping for Variable-Fidelity EM-Driven Design of Compact Circuits
PublicationSpace mapping (SM) belongs to the most successful surrogate-based optimization (SBO) methods in microwave engineering. Among available SM variations, implicit SM (ISM) is particularly attractive due to its simplicity and separation of extractable surrogate model parameters and design variables of the circuit/system at hand. Unlike other SM approaches, ISM exploits a set of preassigned parameters to align the surrogate with the...
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Electromagnetic curtain effect and tunneling properties of multilayered periodic structures
PublicationArtykuł przedstawia analizę rozpraszania fali elektromagnetycznej na wielowarstwowych strukturach periodycznych. W analizowanych strukturach zaobserwowano efekt tunelowania fali oraz efekt przestrajania pasm zaporowych/przepustowych (efekt kurtyny elektromagnetycznej)