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Wyniki wyszukiwania dla: TOPOLOGICALLY-FLEXIBLE ANTENNAS
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Multi-objective optimization for assessment of topological modification in UWB antennas
PublikacjaThis paper addresses an issue of systematic and rigorous assessment of effects of topological modifications on the performance of compact UWB antennas. Application of fast surrogate-assisted multi-objective optimization procedures allows us for obtaining, in a practically acceptable timeframe, a set of designs representing the best possible trade-offs between conflicting objectives (here, antenna size minimization and reduction...
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Fast Multi-Objective Optimization of Narrow-Band Antennas Using RSA Models and Design Space Reduction
PublikacjaComputationally efficient technique for multi-objective design optimization of narrow-band antennas is presented. In our approach, the corrected low-fidelity antenna model (obtained through coarse-discretization EM simulations) is enhanced using frequency scaling and response correction, sampled, and utilized to obtain a fast response surface approximation (RSA) antenna surrogate. The RSA model is constructed in the reduced design space....
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Expedited Gradient-Based Design Closure of Antennas Using Variable-Resolution Simulations and Sparse Sensitivity Updates
PublikacjaNumerical optimization has been playing an increasingly important role in the design of contemporary antenna systems. Due to the shortage of design-ready theoretical models, optimization is mainly based on electromagnetic (EM) analysis, which tends to be costly. Numerous techniques have evolved to abate this cost, including surrogate-assisted frameworks for global optimization, or sparse sensitivity updates for speeding up local...
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Expedited simulation-driven design optimization of UWB antennas by means of response features
PublikacjaIn this work, a method for fast design optimization of broadband antennas is considered. The approach is based on a feature-based optimization (FBO) concept where reflection characteristics of the structure at hand are formulated in terms of suitably defined feature points. Redefinition of the design problem allows for reducing the design optimization cost, because the dependence of feature point coordinates on antenna dimensions...
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Rapid dimension scaling of triple-band antennas by means of inverse surrogate modeling
PublikacjaGeometry scaling of antennas, i.e., finding optimum dimensions of the structure for given operating conditions and material parameters is an important yet challenging problem. In this paper, we discuss fast dimension scaling of triple-band antennas with respect to operating frequencies. We adopt the inverse surrogate modeling approach where the surrogate model is a function of the three operating frequencies of the antenna and...
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Feedline Alterations for Optimization-Based Design of Compact Super-Wideband MIMO Antennas in Parallel Configuration
PublikacjaThis letter presents a technique for size reduction of wideband multiple-input-multiple-output (MIMO) antennas. Our approach is a two-stage procedure. At the first stage, the antenna structure is modified to improve its impedance matching. This is achieved through incorporation of an n-section tapered feedline, followed by reoptimization of geometry parameters. Reducing the maximum in-band reflection well beyond the acceptance...
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Reliable low-cost surrogate modeling and design optimisation of antennas using implicit space mapping with substrate segmentation
PublikacjaAbstract: In this work, a reliable methodology for fast simulation-driven design optimisation of antenna structures is proposed. The authors’ approach exploits implicit space mapping (ISM) technology. To adopt it for handling antenna structures, they introduce substrate segmentation with separate dielectric permittivity value assigned for each segment as ISM preassigned parameters. At the same time, the coarse model for space mapping...
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A novel calibration method for RSS-based DoA estimation using ESPAR antennas
PublikacjaIn this paper, we introduce a new calibration method that can successfully be used in direction of arrival (DoA) estimation using electronically steerable parasitic array radiator (ESPAR) antennas and employing power-pattern cross-correlation (PPCC) algorithm, which relies on received signal strength (RSS) values recorded at the antenna output port. Instead of the commonly used two-step approach, during which ESPAR antenna calibration...
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International Journal of Antennas and Propagation
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Recent Developments in Data-Assisted Modeling of Flexible Proteins
PublikacjaMany proteins can fold into well-defined conformations. However, intrinsically-disordered proteins (IDPs) do not possess a defined structure. Moreover, folded multi-domain proteins often digress into alternative conformations. Collectively, the conformational dynamics enables these proteins to fulfill specific functions. Thus, most experimental observables are averaged over the conformations that constitute an ensemble. In this...
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Scaling of numbers in residue arithmetic with the flexible selection of scaling factor
PublikacjaA scaling technique of numbers in resudue arithmetic with the flexible selection of the scaling factor is presented. The required scaling factor can be selected from the set of moduli products of the Residue Number System (RNS) base. By permutation of moduli of the number system base it is possible to create many auxilliary Mixed-Radix Systems associated with the given RNS with respect to the base, but they have different sets...
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Radiation pattern measurements of geometrically small antennas performed in non-anechoic environments
Dane BadawczeThe dataset contains unprocessed measurements of radiation pattern characteristics performed in non-anechoic regime for three geometrically small antenna structures: a spline-parameterized Vivaldi structure, a compact spline-based monopole, and a quasi-Yagi geometry with enhanced bandwidth. The responses have been obtained over broad frequency ranges...
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Green TPUs from Prepolymer Mixtures Designed by Controlling the Chemical Structure of Flexible Segments
PublikacjaThis study concerns green thermoplastic polyurethanes (TPU) obtained by controlling the chemical structure of flexible segments. Two types of bio-based polyether polyols—poly(trimethylene glycol)s—with average molecular weights ca. 1000 and 2700 Da were used (PO3G1000 and PO3G2700, respectively). TPUs were prepared via a two-step method. Hard segments consisted of 4,4?- diphenylmethane diisocyanates and the bio-based 1,4-butanodiol...
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Accelerated multi-objective design optimization of antennas by surrogate modeling and domain segmentation
PublikacjaMulti-objective optimization yields indispensable information about the best possible design trade-offs of an antenna structure, yet it is challenging if full-wave electromagnetic (EM) analysis is utilized for performance evaluation. The latter is a necessity for majority of contemporary antennas as it is the only way of achieving acceptable modeling accuracy. In this paper, a procedure for accelerated multi-objective design of...
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The Method of Finding the Optimal Spindle Speed When Milling Flexible Details
PublikacjaThe paper presents a new method of vibration reduction during milling of flexible details. The method consists in selecting the optimal spindle speed, based on the natural frequency of the workpiece. For this purpose, an original method was created, which is based on minimizing the work of cutting forces in the direction of the depth of cutting. The effectiveness of the method has been proved by comparing the RMS values of vibration...
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Fast Re-Design of Multi-Band Antennas by Means of Orthogonal-Direction Geometry Scaling and Local Parameter Tuning
PublikacjaApplication-driven design of antenna systems fosters a reuse of structures that have proven competitive in terms of their electrical and field performance, yet have to be re-designed for a new application area. In practice, it most often entails relocation of the operating frequencies or bandwidths, which is an intricate endeavor, normally requiring utilization of numerical optimization techniques. If the center frequencies of...
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Two-Stage Variable-Fidelity Modeling of Antennas with Domain Confinement
PublikacjaSurrogate modeling has become the method of choice in solving an increasing number of antenna design tasks, especially those involving expensive full-wave electromagnetic (EM) simulations. Notwithstanding, the curse of dimensionality considerably affects conventional metamodeling methods, and their capability to efficiently handle nonlinear antenna characteristics over broad ranges of the system parameters is limited. Performance-driven...
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The influence of temperature on properties of the polymer flexible joint used for strengthening historical masonries
PublikacjaA new method of repairing damaged structures by filling the cracks with a specially prepared elastomeric polymer mass has been recently proposed. This new and innovative technique, known as the Flexible Joint Method (FJM), is mainly dedicated to masonries and historical objects, where minimum intervention is permitted. The flexible joint bonds the disrupted elements and ensures further safe exploitation of a damaged structure....
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A design framework for rigorous constrained EM-driven optimization of miniaturized antennas with circular polarization
PublikacjaCompact radiators with circular polarization are important components of modern mobile communication systems. Their design is a challenging process which requires maintaining simultaneous control over several performance figures but also the structure size. In this work, a novel design framework for multi-stage constrained miniaturization of antennas with circular polarization is presented. The method involves sequential optimization...
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Minimization of vibrations during milling of flexible structures using mechatronic design techniques
PublikacjaThe paper presents an innovative effective method of minimizing vibrations during milling of flexible structures, using a new vibration suppression method based on a workpiece holder with adjustable support stiffness. The proposed method is rooted in mechatronic design techniques, which can become a standard procedure for optimizing the milling process.
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Flexible Services and Manufacturing Journal
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UWB-Based Indoor Navigation in a Flexible Manufacturing System Using a Custom Quadrotor UAV
PublikacjaA novel solution for indoor navigation of a transportation drone in flexible manufacturing is presented in this paper. To address the challenges of accurate and robust drone navigation in occluded environments, an ultra-wideband (UWB) navigation system has been integrated with a commercially available open source control platform. The system offers high accuracy (± 20 mm), low power consumption, resistance to electronic interference,...
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On low-fidelity models for variable-fidelity simulation-driven design optimization of compact wideband antennas
PublikacjaThe paper addresses simulation-driven design optimization of compact antennas involving variable-fidelity electromagnetic (EM) simulation models. Comprehensive investigations are carried out concerning selection of the coarse model discretization density. The effects of the low-fidelity model setup on the reliability and computational complexity of the optimization process are determined using a benchmark set of three ultra-wideband...
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Microstructure, mechanical properties, and flame retardancy of nanoclay-incorporated polyurethane flexible foam composites
PublikacjaThe present work seeks to investigate microstructure, mechanical properties, and flame retardancy of polyurethane/nanoclay flexible foam composites. In this regard, we prepared various nanocomposites with and without nanoclay and observed the resulting morphologies to correlate them with the other corresponding characteristics. The results provided support for the fact that tensile strength and compression set will increase with...
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Rapid Re-Design and Bandwidth/Size Trade-Offs for Compact Wideband Circular Polarization Antennas Using Inverse Surrogates and Fast EM-Based Parameter Tuning
PublikacjaDesign of compact wideband circularly polarized (CP) antennas is challenging due to the necessity of simultaneous handling of several characteristics (reflection, axial ratio, gain) while maintaining a small size of the structure. Antenna re-design for various operating bands is clearly more difficult yet practically important because intentional reduction of the bandwidth (e.g., by moving the lower edge of the operating band up...
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Comprehensive Investigation of Stoichiometry–Structure–Performance Relationships in Flexible Polyurethane Foams
PublikacjaPolyurethane (PU) foams are versatile materials with a broad application range. Their performance is driven by the stoichiometry of polymerization reaction, which has been investigated in several works. However, the analysis was often limited only to selected properties and compared samples differing in apparent density, significantly influencing their performance. In the bigger picture, there is still a lack of comprehensive studies...
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Enhancing the Seismic Resistance of Columns by GFRP Confinement Using Flexible Adhesive-Experimental Study
PublikacjaIn this paper, the results of two experiments, focused on testing the effectiveness of a method of enhancing the seismic (dynamic) resistance of masonry columns with the use of flexible polymer adhesive, are shown. The first experiment was devoted to investigate the damping properties of a polymer working between two stiff layers, whereas the aim of the second one was to verify if the identified damping properties of the polymer...
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Application and evaluation of M-EPDG for performance analysis of Polish typical flexible and rigid pavements
PublikacjaThe main goal of the paper is to implement and evaluate the M-EPDG and the software AASHTOware to analyse the performance of new flexible and rigid pavements designed according to the Polish catalogues, which are comparable with analogous catalogues used in other European countries. For this purpose the site-specific inputs for Poland were determined and described in the paper as well as compared to the default input data used...
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Studies on the influence of technological variants of finishing machining on flow of parts in flexible manufacturing
PublikacjaIn the article below the problems of influence of variants of finishing processing on flow of machining parts in flexible manufacturing system were presented. The investigations were carried out the technological processes for piston rods and rams of hydraulic cylinders. There were also presented model variants of technological processes for piston rods finished with the burnishing. In these studies the influence of technological...
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Low-strain sensor based on the flexible boron-doped diamond-polymer structures
PublikacjaA free-standing high boron-doped diamond nanosheet (BDDNS) has been fabricated for the development of a flexible BDDNS strain senor. High boron-doped diamond was initially grown on a tantalum substrate in a microwave plasma-assisted chemical vapor deposition method, and was then transferred to a Kapton polymer substrate to fabricate the flexible BDDNS/Kapton device. Before performing the transfer process, the thin BDDNS’s morphology...
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Impact of overloaded vehicles on load equivalency factors and service period of flexible pavements
PublikacjaOverloaded vehicles occur less frequently in comparison to properly loaded vehicles but due to their greater potential to cause damage they significantly contribute to the distress of pavement structure. As the studies show, the phenomena of vehicles overloading intensifies when the control of traffic is poor and the average percentage of overloaded vehicles on analyzed roads varies from 6% to 23%. The main goal of the ar-ticle...
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Decisional DNA based intelligent knowledge model for flexible manufacturing system
PublikacjaModeling an effective mechanism for design and control strategies for the implementation of a flexible manufacturing system (FMS) has been a challenge. Consequently, to overcome this issue various techniques have applied in the past but most of these models are effective only for some specific situation or an element of FMS. In this study, the knowledge representation technique of Decisional DNA (DDNA) is applied to FMS to develop...
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Comprehensive dimension scaling of multi-band antennas for operating frequencies and substrate parameters
PublikacjaIn this paper, low-cost and comprehensive redesign of multi-band antennas with respect to the operating frequencies and material parameters of the substrate is presented. Our approach exploits an inverse surrogate model identified based on a set of reference designs optimized at the level of coarse-discretization EM simulations of the antenna at hand. An iterative correction procedure is also implemented to account for the initial...
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Cost-Efficient Behavioral Modeling of Antennas by Means of Global Sensitivity Analysis and Dimensionality Reduction
PublikacjaComputational tools, particularly electromagnetic (EM) solvers, are now commonplace in antenna design. While ensuring reliability, EM simulations are time-consuming, leading to high costs associated with EM-driven procedures like parametric optimization or statistical design. Various techniques have been developed to address this issue, with surrogate modeling methods garnering particular attention due to their potential advantages....
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IEEE ANTENNAS AND PROPAGATION MAGAZINE
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Novel Coplanar-Strip-Based Excitation Technique for Design of Broadband Circularly Polarization Antennas with Wide 3-dB Axial Ratio Beamwidth
PublikacjaIn this paper, a novel excitation technique for design of a single-point-fed compact low-profile wide-slot antennas with broadband circular polarization (CP) and wide 3 dB axial ratio (AR) beamwidth is presented. Two inverted L-shape parasitic strips placed coplanar to the microstrip line of an asymmetric CPW, and a horizontal strip that protrudes from the vertical edge of the backside ground plane of the substrate are used for...
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A Comprehensive Survey on Antennas On-Chip Based on Metamaterial, Metasurface, and Substrate Integrated Waveguide Principles for Millimeter-Waves and Terahertz Integrated Circuits and Systems
PublikacjaAntennas on-chip are a particular type of radiating elements valued for their small footprint. They are most commonly integrated in circuit boards to electromagnetically interface free space, which is necessary for wireless communications. Antennas on-chip radiate and receive electromagnetic (EM) energy as any conventional antennas, but what distinguishes them is their miniaturized size. This means they can be integrated inside...
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Expedited Yield Optimization of Narrow- and Multi-Band Antennas Using Performance-Driven Surrogates
PublikacjaUncertainty quantification is an important aspect of engineering design, also pertaining to the development and performance evaluation of antenna systems. Manufacturing tolerances as well as other types of uncertainties, related to material parameters (e.g., substrate permittivity) or operating conditions (e.g., bending) may affect the antenna characteristics. In the case of narrow- or multi-band antennas, this usually leads to...
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Transmission measurements between two geometrically small Vivaldi antennas performed in non-anechoic propagation conditions
Dane BadawczeThe dataset contains unprocessed measurements of complex transmission (and reflection) characteristics obtained in non-anechoic regime for a geometrically small, broadband spline-parameterized Vivaldi structure. The measurement setup comprises two Vivaldi antennas with the same topology where one is used as a reference structure, and another one as...
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Rapid redesign of multiband antennas with respect to operating conditions and material parameters of substrate
PublikacjaThis work addresses geometry parameter scaling of multi-band antennas for Internet of Things applications. The presented approach is comprehensive and permits re-design of the structure with respect to both the operating frequencies and material parameters of the dielectric substrate. A two-step procedure is developed with the initial design obtained from an inverse surrogate model constructed using a set of appropriately prepared...
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Comparative analysis of the flow control over a circular cylinder with detached flexible and rigid splitter plates
PublikacjaA comparative study is performed on a circular cylinder with both flexible and rigid splitter plates (SPs). This study has the novelty of using single and dual detached SPs located downstream of the cylinder. The dimensionless gap distance between the first splitter plate and the cylinder as well as the distance between the SPs are varied. The strain of flexible SPs can be used for energy harvesting from the flow. Therefore, a...
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Numerically efficient algorithm for compact microwave device optimization with flexible sensitivity updating scheme
PublikacjaAn efficient trust-region algorithm with flexible sensitivity updating management scheme for electromagnetic (EM)-driven design optimization of compact microwave components is proposed. During the optimization process, updating of selected columns of the circuit response Jacobian is performed using a rank-one Broyden formula (BF) replacing finite differentiation (FD). The FD update is omitted for directions sufficiently well aligned...
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Synthesis and thermal studies of flexible polyurethane nanocomposite foams obtained using nanoclay modified with flame retardant compound
PublikacjaThis work presents thermal studies of nanocomposites based on the flexible polyurethane (PU) matrix and filled using montmorillonite organically modified with organophosphorus flame retardant compound. Flexible PU nanocomposite foams were prepared in the reaction carried out between reactive alcoholic hydroxyl and isocyanate groups with the ratio of NCO to OH groups equal to 1.05. The amount of an organoclay ranging from 3 to 9...
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Vibration surveillance for efficient milling of flexible details fixed in adjustable stiffness holder
PublikacjaThe paper presents the results of research related to the possibility of using an intelligent workpiece holder with adjustable stiffness, during end milling process. Machining a one side supported flexible workpiece will be performed with constant spindle speed and feed speed. In order to avoid hazardous vibration, stiffness of the especially designed spring (mounted in a workpiece holder) will be modified off-line. In order to...
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A framework for accelerated optimization of antennas using design database and initial parameter set estimation
PublikacjaThe purpose of this paper is to exploit a database of pre-existing designs to accelerate parametric optimization of antenna structures is investigated. Design/methodology/approach The usefulness of pre-existing designs for rapid design of antennas is investigated. The proposed approach exploits the database existing antenna base designs to determine a good starting point for structure optimization and its response sensitivities....
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A Low-Profile 3-D Printable Metastructure for Performance Improvement of Aperture Antennas
PublikacjaIn order to increase the radiation performance of aperture-type antennas, this paper demonstrates a low-profile, planar, single-layer, three-dimensional (3-D) printable metastructure. The proposed hybridized metastructure is highly transparent as it is made out of novel hybrid meta-atoms having transmission coefficient magnitudes greater than -0.72 dB and fully complies with the near-field phase transformation principle. The hybridized...
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VIBRATION SURVEILLANCE DURING MILLING OF FLEXIBLE DETAILS WITH A USE OF THE ACTIVE OPTIMAL CONTROL
PublikacjaThe main goal of modern machining operations is to achieve increasingly better performance. High Speed Machining and/or High Performance Cutting, despite a lot of advantages, have also some drawbacks, for example, a possibility of losing stability and development of self-excited chatter vibration. This paper presents an approach of vibration surveillance during high speed milling with a use of active optimal control. Non-stationary...
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The rigid and flexible road pavements in terms of life cycle costs
PublikacjaThe cost of road pavement construction, its durability and reliability depends on many factors, including: the scope and detail of the technical design, quality of work but also the scope of works related to its maintenance, conservation and operation. Determining the amount of rational expenses, in terms of the life cycle cost of the pavement, requires determination and consideration of the above issues, already at the planning...
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Optimal spindle speed determination for vibration reduction during ball-end milling of flexible details
PublikacjaIn the paper a method of optimal spindle speed determination for vibration reduction during ball-end milling of flexible details is proposed. In order to reduce vibration level, an original procedure of the spindle speed optimisation, based on the Liao–Young criterion, is suggested. As the result, an optimal, constant spindle speed value is determined. For this purpose, on-stationary computational model of machining process is...
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Design-oriented computationally-efficient feature-based surrogate modelling of multi-band antennas with nested kriging
PublikacjaDesign of modern antenna structures heavily depends on electromagnetic (EM) simulation tools. EM analysis provides reliable evaluation of increasingly complex designs but tends to be CPU intensive. When multiple simulations are needed (e.g., for parameters tuning), the aggregated simulation cost may become a serious bottleneck. As one possible way of mitigating the issue, the recent literature fosters utilization of faster representations,...