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Wyniki wyszukiwania dla: ANTENNA ARRAYS, ISOLATION TECHNIQUE, DEFECTED GROUND PLANE (DGP), DECOUPLING DOT-WALL, SQUARE RING RESONANT ELEMENTS
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Quality assessment of varistor ZnO structures by resonant ultrasound spectroscopy
PublikacjaWarystory sa wytwarzane z tlenku cynku ZnO jako cylindrycznie uformowane struktury, a ich jakość zależy od zmieniających się uwarunkowań technologicznych na etapach formowania ich kształtu oraz spiekania. W związku z tym są one testowane w końcowej fazie produkcji, a elementy wadliwe się odrzuca. Proponujemy testowanie jakości struktur ZnO we wcześniejszej fazie ich wytwarzania w celu wyeliminowania elementów wadliwych z dalszej,...
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Effectiveness of a mathematical model in simulating nonlinear mechanical behaviour of a seismic isolation system made of polymeric bearings
PublikacjaThe present study was focused on determining the effectives of a nonlinear mathematical model in simulating complex mechanical behaviour of a seismic isolation system made of Polymeric Bearings. The proposed mathematical model defines the lateral force as a nonlinear function of the shear displacement and the deformation velocity. The effectiveness of the proposed mathematical model was verified by comparing the seismic response...
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Expedited Acquisition of Database Designs for Reduced-Cost Performance-Driven Modeling and Rapid Dimension Scaling of Antenna Structures
PublikacjaFast replacement models have been playing an increasing role in high-frequency electronics, including the design of antenna structures. Their role is to improve computational efficiency of the procedures that normally entail large numbers of expensive full-wave electromagnetic (EM) simulations, e.g., parametric optimization or uncertainty quantification. Recently introduced performance-driven modeling methods, such as the nested...
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Ring Opening of Triflates Derived from Benzophospholan-3-one Oxides by Aryl Grignard Reagents as a Route to 2‑Ethynylphenyl(diaryl)phosphine Oxides
PublikacjaA new simple method for the synthesis of 2-ethynylphenyl(diaryl)phosphine oxides via ring opening of benzophosphol-3-yl triflates has been developed. This process occurs via nucleophilic attack of a Grignard reagent at the phosphorus center, which results in ring opening and cleavage of a leaving group. The reaction proceeds under mild conditions and, within 15−60 min, leads to a library of previously unavailable 2-ethynylphenylphosphine...
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EM-Driven Multi-Objective Optimization of Antenna Structures in Multi-Dimensional Design Spaces
PublikacjaFeasible multi-objective optimization of antenna structures is presented. An initial set of Pareto optimal solutions is found using a multi-objective evolutionary algorithm (MOEA) working with a fast surrogate antenna model obtained by kriging interpolation of coarse-discretization EM simulation data. To make the surrogate construction computationally feasible in multi-dimensional design space, the space subset containing non-dominated...
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Feedback Control of Multiphase Induction Machines with Backstepping Technique
PublikacjaThe paper presents the control possibility of five phase induction machines. In the proposed solution the machine model vector form is not transformed to the (dq)-coordinate system, that is connected to rotor flux vector, but utilizes the stationary system ( αβ ). Moreover, the nonlinear model linearization is based on demonstrated nonlinear variables transformation for i-orthogonal ( αβ )(n) planes. By introducing the backstepping...
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Elements of Bioinformatics 2021/22
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Elements of Bioinformatics 2022/23
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Elements of Law - winter 2023
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Elements of Bioinformatics 2023/24
Kursy Online -
Polyurethane/ground tire rubber composite foams based on polyglycerol: processing, mechanical and thermal properties
PublikacjaDuring the synthesis of rigid polyurethane foams, petrochemical polyol was substituted with polyglycerol, the product of thermo-catalytic polycondensation of waste glycerol, resulting from biodiesel production. Two types of ground tire rubbers, untreated and thermo-mechanically reclaimed, were used to obtain ‘‘green’’ polyurethane-polyglycerol composite foams. Samples were prepared by a single-step method for the ratio of NCO/OH...
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Low-cost 3D Printed Circularly Polarized Lens Antenna for 5.9 GHz V2X Applications
PublikacjaThis paper presents design and realization of a circularly polarized antenna consisting of a linearly polarized patch antenna and a 3D printed lens, at the same time performing the functions of wave collimator and a polarizer. The antenna is dedicated for 802.11p systems, as a part of road infrastructure, with operation bandwidth 5.85 - 5.925 GHz. Its realised gain and axial ratio at center frequency 5.9 GHz are 14.3 dBi and 2.17...
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Novel doubly perforated broadband microstrip branch-line couplers
PublikacjaTwo broadband compact doubly perforated hybrid couplers have been designed, manufactured, and measured. To improve frequency characteristics and to reduce circuit dimensions, two kinds of perforations have been introduced: the defected ground structures in the ground plane metallization and photonic bandgap cells in the strip metallization. Measurement results show essential miniaturization (~39% and ~36%) and enhancement of the...
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International Journal of Geosynthetics and Ground Engineering
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Isolation of the relative decrease in magnetic permeability contribution to reluctance of an open magnetic circuit based on stray field measurements
PublikacjaThe goal of the study was to evaluate a relative decrease in magnetic permeability in open magnetic circuits based on stray magnetic field measurements. The boundary element method was used to simulate magnetic circuits with variable geometry and variable magnetic permeability. The simulated magnetic circuits were rectangular or bone-shaped flat samples. Reluctance was increased in the middle of the samples resulting in leakage...
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Expedited antenna optimization with numerical derivatives and gradient change tracking
PublikacjaDesign automation has been playing an increasing role in the development of novel antenna structures for various applications. One of its aspects is electromagnetic (EM)-driven design closure, typically applied upon establishing the antenna topology, and aiming at adjustment of geometry parameters to boost the performance figures as much as possible. Parametric optimization is often realized using local methods given usually reasonable...
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Rotational Design Space Reduction for Cost-Efficient Multi-Objective Antenna Optimization
PublikacjaCost-efficient multi-objective design of antenna structures is presented. Our approach is based on design space reduction algorithm using auxiliary single-objective optimization runs and coordinate system rotation. The initial set of Pareto-optimal solutions is obtained by optimizing a response surface approximation model established in the reduced space using coarse-discretization EM simulation data. The optimization engine is...
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Fast Simulation-Driven Design of a Planar UWB Dipole Antenna with an Integrated Balun
PublikacjaThe paper presents a design of an ultra-wideband (UWB) antenna with an integrated balun. A fully planar balun interfacing the microstrip input of the structure to the coplanar stripline (CPS) input of the dipole antenna is introduced. The electromagnetic (EM) model of the structure includes the dipole, the balun, and the microstrip input to account for interactions over the UWB band. The EM model is adjusted for low reflection...
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Expedited Metaheuristic-Based Antenna Optimization Using EM Model Resolution Management
PublikacjaDesign of modern antenna systems heavily relies on numerical opti-mization methods. Their primary purpose is performance improvement by tun-ing of geometry and material parameters of the antenna under study. For relia-bility, the process has to be conducted using full-wave electromagnetic (EM) simulation models, which are associated with sizable computational expendi-tures. The problem is aggravated in the case of global optimization,...
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Kriging metamodels and design re‐utilization for fast parameter tuning of antenna structures
PublikacjaThe paper addresses the problem of computationally efficient electromagnetic (EM)‐driven design closure of antenna structures. The foundations of the presented approach are fast kriging interpolation metamodels, utilized for two purposes: (a) producing a good starting point for further parameter tuning, and (b) yielding a reasonable Jacobian matrix estimate to jump‐start the optimization procedure. The models are rendered using...
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Tolerance Optimization of Antenna Structures by Means of Response Feature Surrogates
PublikacjaFabrication tolerances and other types of uncertainties, e.g., the lack of precise knowledge of material parameters, have detrimental effects on electrical and field performance of antenna systems. In the case of input characteristics these are particularly noticeable for narrow- and multi-band antennas where deviations of geometry parameters from their nominal values lead to frequency shifts of the operating frequency bands. Improving...
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Rapid Variable-Resolution Parameter Tuning of Antenna Structures Using Frequency-Based Regularization and Sparse Sensitivity Updates
PublikacjaGeometry parameter tuning is an inherent part of antenna design process. While most often performed in a local sense, it still entails considerable computational expenses when carried out at the level of full-wave electromagnetic (EM) simulation models. Moreover, the optimization outcome may be impaired if good initial design is not available. This paper proposes a novel approach to fast and improved-reliability gradient-based...
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Modification of Ground Tire Rubber—Promising Approach for Development of Green Composites
PublikacjaGround tire rubber (GTR) was mechano-chemically modified using a road bitumen 100/150 and two types of organic peroxides: di-(2-tert-butyl-peroxyisopropyl)-benzene (BIB) and dicumyl peroxide (DCP). The impact of used additives on reactive sintering efficiency and physico-mechanical properties of modified GTR was investigated using oscillating disc rheometer measurements, followed by tensile tests and swelling behavior studies....
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Filtering EBG Structures Implemented in Coplanar Waveguide Feedline of Planar Slot Antenna
PublikacjaA novel compact dual-band slot antenna fed by a coplanar waveguide (CPW) incorporating electromagnetic band gap (EBG) structures has been proposed. At first, a classic wideband slot antenna fed by a CPW, dedicated to work in 2 ÷ 18 GHz band, has been designed. Subsequently, by adding simple EBG filtering structures into a CPW feedline, a dual-band performance ranging from 2.5 to 5.3 GHz and from 13.5 to 16.3 GHz, with the voltage...
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Degradation of stiffness of building columns exposed to bending and impact load during ground motions
PublikacjaThe safety of civil engineering structures under external loads, including ground motions, is one of the issues related to the idea of sustainable society. The earthquake-induced soft-storey failure is a typical type of damage observed in buildings due to seismic excitation. The failure of an intermediate soft storey of a structure results in large vertical impact loading acting on the lower floors due to the fall of the upper...
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Billiard in a rotating half-plane: modeling and dynamics
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On numerical calculation of acoustic field of plane source.
PublikacjaSkładowe harmoniczne wiązki akustycznej zostały obliczone na podstawie reprezentacji w postaci całek według teorii reprezentacji. Zastosowano nowe metody do obliczania całek od funkcji szybko oscylacyjnych.
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Polarization of a Plane Wave Scattered by an Array of Cylinders.
PublikacjaAnaliza rozpraszania fali elektromagnetycznej o polaryzacji TE i TM na szyku metalowych i dielektrycznych cylindrów, przy wykorzystaniu zmodyfikowanej procedury iteracyjnej i metody dopasowania rodzajów. Parametry polaryzacyjne fali rozproszonej określone są w strefie bliskiej i dalekiej.
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Plane Wave Scattering by Bow-Tie Posts.
PublikacjaRozwinięcie teorii rozpraszania w wolnej przestrzeni na cylindrycznych obiektach typu "Bow-Tie" pobudzanych falą płaską przy użyciu zmodyfikowanej procedury iteracyjnej i metody dopasowania rodzajów. Wynikiem analizy są charakterystyki pola rozproszonego w strefie bliskiej i dalekiej. Struktura typu "Bow-Tie" składa się z dwóch wycinków metalowego cylindra połączonych dielektrycznym lub metalowych cylindrem. W odróżnieniu zwykłych...
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Plane wave scattering by an array of circular cylinders
PublikacjaMetodę dopasowania rodzajów zastosowano do połączenia zastępczego pola rozproszonego od dowolnej konfiguracji dwuwarstwowych prętów ferrytowych i dielektrycznych z pobudzeniem falą płaską. Zaprezentowano charakterystyki rozpraszania zarówno w strefie dalekiej jaki i bliskiej dla kilku konfiguracji prętów przy pobudzeniu falą płaską.
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Plane wave scattering by an array of metamaterial cylinders
PublikacjaMetodę dopasowania rodzajów zastosowano do połączenia zastępczego pola rozproszonego od dowolnej konfiguracji prętów dielektrycznych lub wykonanych z metamateriału z pobudzeniem falą płaską. Zaprezentowano charakterystyki rozpraszania w strefie dalekiej dla jednego i dwóch prętów dielektrycznych lub wykonanych z metamateriału przy pobudzeniu falą płaską.
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Study on polymer elements for mitigation of earthquake-induced pounding between buildings in complex arrangements
PublikacjaPounding between neighbouring buildings during earthquakes has been identified as one of the reasons for substantial damage or even total collapse of colliding structures, so it has been the subject of numerous studies in the recent years. A major reason leading to interactions between adjacent, insufficiently separated structures results from the differences in their dynamic properties. The problem is much more complicated for...
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Generalized Formulation of Response Features for Reliable Optimization of Antenna Input Characteristics
PublikacjaElectromagnetic (EM)-driven parameter adjustment has become imperative in the design of modern antennas. It is necessary because the initial designs rendered through topology evolution, parameter sweeping, or theoretical models, are often of poor quality and need to be improved to satisfy stringent performance requirements. Given multiple objectives, constraints, and a typically large number of geometry parameters, the design closure...
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Timber-frame house resistant to dynamic loads - analysis of wall panel filled with polyurethane foam
PublikacjaThe present study shows the experimentally and numerically determined response of a single timber-frame house wall panel filled with polyurethane (PU) foam under dynamic loads. The harmonic tests were conducted for the following frequencies: 0.5 Hz, 1.0 Hz, 2.0 Hz and 5.0 Hz for various values of the specified displacement. Based on the results of the comparison between the experimental tests and the numerical analyses, the numerical...
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Variable‐fidelity modeling of antenna input characteristics using domain confinement and two‐stage Gaussian process regression surrogates
PublikacjaThe major bottleneck of electromagnetic (EM)-driven antenna design is the high CPU cost of massive simulations required by parametric optimization, uncertainty quantification, or robust design procedures. Fast surrogate models may be employed to mitigate this issue to a certain extent. Unfortunately, the curse of dimensionality is a serious limiting factor, hindering the construction of conventional data-driven models valid over...
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Hyperbolic Asynchronous Method of a Radio Navigation Technique
PublikacjaHumans have always wanted to determine position in an unknown environment. At the beginning methods were simple. They were based on the observation of characteristic points, in the case of shipping additional observations of the coastline. Then came navigation based on astronomical methods (astronavigation). At the beginning of the XX-century a new way of determining the current location was developed. It has used radiowave signals....
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Accurate Modeling of Antenna Structures by Means of Domain Confinement and Pyramidal Deep Neural Networks
PublikacjaThe importance of surrogate modeling techniques has been gradually increasing in the design of antenna structures over the recent years. Perhaps the most important reason is a high cost of full-wave electromagnetic (EM) analysis of antenna systems. Although imperative in ensuring evaluation reliability, it entails considerable computational expenses. These are especially pronounced when carrying out EM-driven design tasks such...
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Theoretical studies of the pyranose ring under mechanical stress
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Research on protection mechanisms of Resilient Packet Ring Network.
PublikacjaPaper describes iSteering - a new method to control traffic in case of RPR network failure. There's comparison of packet wrapping, steering and our proposed method iSteering, which can be used in case of transmitter/receiver or fiber failure. Numerical analysis for even and random traffic flow has been made in order to compare packet wrapping, steering and iSteering. The results of all the tests are included.
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Research on protection mechanisms of Resilient Packet Ring Network.
Publikacja.
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Elementary, binary and schlesinger transformations in differential ring geometry
PublikacjaPrzedstawiono elementarne przekształcenia Darboux dla rozwiązania równań różniczkowych w pierścieniu. Przedstawiono nowe rozwiązania za pomocą przekształcenia Shlesingera jako granicy elementarnego pD.
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Numerically Efficient Miniaturization-Oriented Optimization of an Ultra-Wideband Spline-Parameterized Antenna
PublikacjaDesign of ultra-wideband radiators for modern handheld applications is a challenging task that involves not only selection of an appropriate topology, but also its tuning oriented towards balancing the electrical performance and size. In this work, a low-cost design of a compact, broadband, spline-parameterized monopole antenna has been considered. The framework used for the structure design implements trust-region-based methods,...
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Domain Reduction in Hybrid Technique for Electromagnetic Wave Scattering Problems
PublikacjaThis paper proposes a combination of the field matching technique, finite element method and generalized impedance matrix, the main idea of which is to reduce the computational domain by surrounding a scatterer with the smallest convex shape and applying the field matching technique. This approach can be applied for arbitrary shaped scatterers and types of materials and allows for the reduction of the computational domain. In order...
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Rapid design closure of linear microstrip antenna array apertures using response features
PublikacjaA simple yet reliable approach to a rapid design closure of linear antenna array apertures at the electromagnetic (EM)-simulation level is proposed. Our methodology exploits an underlying array factor (AF) model suitably corrected by means of characteristic points (angles and levels) of the radiation pattern of the EM model of the antenna array aperture. This conveniently allows for controlling both the side lobe levels...
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Magdalena Rucka prof. dr hab. inż.
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Integrated controller for ultra high frequency technique laboratory
PublikacjaDepartment of Microwave and Antenna Engineering decided to modernize the laboratory of Ultra High Frequency Techniques. The main change was to replace measurement of the field distribution inside rectangular waveguides by analysing the fields around striplines. This involved the need to overcome several technical and conceptual problems. Precise positioning of the probe and reading the field distribution near the stripline is important...
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THE USE OF GREEN LOGISTICS ELEMENTS DURING THE CONSTRUCTION OF OFFSHORE VESSELS
PublikacjaThe article is aimed at the presentation referring to the use of green logistics elements during the construction of the offshore vessels in the following aspects: collection, removal and utilisation of any waste that is harmful for natural environment, elimination of the negative impact that such waste can have on natural environment and the search for the optimal solutions as regards these aspects.
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Reduced-Cost Constrained Modeling of Microwave and Antenna Components: Recent Advances
PublikacjaElectromagnetic (EM) simulation models are ubiquitous in the design of microwave and antenna components. EM analysis is reliable but CPU intensive. In particular, multiple simulations entailed by parametric optimization or uncertainty quantification may considerably slow down the design processes. In order to address this problem, it is possible to employ fast metamodels. Here, the popular solution approaches are approximation...
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Nested Space Mapping Technique for Design and Optimization of Complex Microwave Structures with Enhanced Functionality
PublikacjaIn this work, we discuss a robust simulation-driven methodology for rapid and reliable design of complex microwave/RF circuits with enhanced functionality. Our approach exploits nested space mapping (NSM) technology, which is dedicated to expedite simulation-driven design optimization of computationally demanding microwave structures with complex topologies. The enhanced func-tionality of the developed circuits is achieved by means...
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Reduced-cost electromagnetic-driven optimisation of antenna structures by means of trust-region gradient-search with sparse Jacobian updates
PublikacjaNumerical optimisation plays more and more important role in the antenna design. Because of lack of design-ready theoretical models, electromagnetic (EM)-simulation-driven adjustment of geometry parameters is a necessary step of the design process. At the same time, traditional parameter sweeping cannot handle complex topologies and large number of design variables. On the other hand, high computational cost of the conventional...