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Wyniki wyszukiwania dla: surrogate modeling

Fundamentals of DataDriven Surrogate Modeling
PublikacjaThe primary topic of the book is surrogate modeling and surrogatebased design of highfrequency structures. The purpose of the first two chapters is to provide the reader with an overview of the two most important classes of modeling methods, datadriven (or approximation), as well as physicsbased ones. These are covered in Chapters 1 and 2, respectively. The remaining parts of the book give an exposition of the specific aspects...

Fundamentals of PhysicsBased Surrogate Modeling
PublikacjaChapter 1 was focused on datadriven (or approximationbased) modeling methods. The second major class of surrogates are physicsbased models outlined in this chapter. Although they are not as popular, their importance is growing because of the challenges related to construction and handling of approximation surrogates for many realworld problems. The high cost of evaluating computational models, nonlinearity of system responses,...

Triangulationbased Constrained Surrogate Modeling of Antennas
PublikacjaDesign of contemporary antenna structures is heavily based on fullwave electromagnetic (EM) simulation tools. They provide accuracy but are CPUintensive. Reduction of EMdriven design procedure cost can be achieved by using fast replacement models (surrogates). Unfortunately, standard modeling techniques are unable to ensure sufficient predictive power for realworld antenna structures (multiple parameters, wide parameter ranges,...

PerformanceDriven Surrogate Modeling of HighFrequency Structures
PublikacjaThe development of modern highfrequency structures, including microwave and antenna components, heavily relies on fullwave electromagnetic (EM) simulation models. Notwithstanding, EMdriven design entails considerable computational expenses. This is especially troublesome when solving tasks that require massive EM analyzes, parametric optimization and uncertainty quantification being representative examples. The employment of...

Global Surrogate Modeling by Neural NetworkBased Model Uncertainty
PublikacjaThis work proposes a novel adaptive global surrogate modeling algorithm which uses two neural networks, one for prediction and the other for the model uncertainty. Specifically, the algorithm proceeds in cycles and adaptively enhances the neural networkbased surrogate model by selecting the next sampling points guided by an auxiliary neural network approximation of the spatial error. The proposed algorithm is tested numerically...

PerformanceBased Nested Surrogate Modeling of Antenna Input Characteristics
PublikacjaUtilization of electromagnetic (EM) simulation tools is mandatory in the design of contemporary antenna structures. At the same time, conducting designs procedures that require multiple evaluations of the antenna at hand, such as parametric optimization or yielddriven design, is hindered by a high cost of accurate EM analysis. To certain extent, this issue can be addressed by utilization of fast replacement models (also referred...

On ReducedCost DesignOriented Constrained Surrogate Modeling of Antenna Structures
PublikacjaDesign of contemporary antenna structures heavily relies on fullwave electromagnetic (EM) simulation models. Such models are essential to ensure reliability of evaluating antenna characteristics, yet, they are computationally expensive and therefore unsuitable for handling tasks that require multiple analyses, e.g., parametric optimization. The cost issue can be alleviated by using fast surrogate models. Conventional datadriven...

Recent Advances in PerformanceDriven Surrogate Modeling of HighFrequency Structures
PublikacjaDesign of high‐frequency structures, including microwave and antenna components, heavily relies on full‐wave electromagnetic (EM) simulation models. Their reliability comes at a price of a considerable computational cost. This may lead to practical issues whenever numerous EM analyses are to be executed, e.g., in the case of parametric optimization. The difficulties entailed by massive simulations may be mitigated by the use of...

Rapid Design of 3D Reflectarray Antennas by Inverse Surrogate Modeling and Regularization
PublikacjaReflectarrays (RAs) exhibit important advantages over conventional antenna arrays, especially in terms of realizing pencilbeam patterns without the employment of the feeding networks. Unfortunately, microstrip RA implementations feature narrow bandwidths, and are severely affected by losses. A considerably improved performance can be achieved for RAs involving grounded dielectric layers, which are also easy to manufacture using...

Surrogate Modeling and Optimization Using ShapePreserving Response Prediction: A Review
PublikacjaComputer simulation models are ubiquitous in modern engineering design. In many cases, they are the only way to evaluate a given design with sufficient fidelity. Unfortunately, an added computational expense is associated with higher fidelity models. Moreover, the systems being considered are often highly nonlinear and may feature a large number of designable parameters. Therefore, it may be impractical to solve the design problem...

Iterative Global Sensitivity Analysis Algorithm with Neural Network Surrogate Modeling
PublikacjaGlobal sensitivity analysis (GSA) is a method to quantify the effect of the input parameters on outputs of physicsbased systems. Performing GSA can be challenging due to the combined effect of the high computational cost of each individual physicsbased model, a large number of input parameters, and the need to perform repetitive model evaluations. To reduce this cost, neural networks (NNs) are used to replace the expensive physicsbased...

Rapid dimension scaling of tripleband 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 tripleband 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...

Expedited VariableResolution Surrogate Modeling of Miniaturized Microwave Passives in Confined Domains
PublikacjaDesign of miniaturized microwave components is largely based on computational models, primarily, fullwave electromagnetic (EM) simulations. EM analysis is capable of giving an accurate account for crosscoupling effects, substrate and radiation losses, or interactions with environmental components (e.g., connectors). Unfortunately, direct execution of EMbased design tasks such as parametric optimization or uncertainty quantification,...

Accelerated multiobjective design optimization of antennas by surrogate modeling and domain segmentation
PublikacjaMultiobjective optimization yields indispensable information about the best possible design tradeoffs of an antenna structure, yet it is challenging if fullwave 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 multiobjective design of...

Inverse surrogate modeling for lowcost geometry scaling of microwave and antenna structures
PublikacjaPurpose–The purpose of this paper is to investigate strategies for expedited dimension scaling ofelectromagnetic (EM)simulated microwave and antenna structures, exploiting the concept of variablefidelity inverse surrogate modeling.Design/methodology/approach–A fast inverse surrogate modeling technique is described fordimension scaling of microwave and antenna structures. The model is established using referencedesigns obtained...

LowCost Surrogate Modeling of Miniaturized Microwave Components Using Nested Kriging
PublikacjaIn the paper, a recently reported nested kriging methodology is employed for modeling of miniaturized microwave components. The approach is based on identifying the parameter space region that contains highquality designs, and, subsequently, rendering the surrogate in this subset. The results obtained for a miniaturized unequalpowersplit ratrace coupler and a compact threesection impedance transformer demonstrate reliability...

LowCost DataDriven Surrogate Modeling of Antenna Structures by Constrained Sampling
PublikacjaFullwave electromagnetic (EM) analysis has become one of the major design tools for contemporary antenna structures. Although reliable, it is computationally expensive which makes automated simulationdriven antenna design (e.g., parametric optimization) difficult. This difficulty can be alleviated by utilization of fast and accurate replacement models (surrogates). Unfortunately, conventional datadriven modeling of antennas...

Expedited Geometry Scaling of Compact Microwave Passives by Means of Inverse Surrogate Modeling
PublikacjaIn this paper, the problem of geometry scaling of compact microwave structures is investigated. As opposed to conventional structures (i.e., constructed using uniform transmission lines), redesign of miniaturized circuits (e.g., implemented with artificial transmission lines, ATSs) for different operating frequencies is far from being straightforward due to considerable crosscouplings between the circuit components. Here, we...

Nested Kriging with Variable Domain Thickness for Rapid Surrogate Modeling and Design Optimization of Antennas
PublikacjaDesign of modern antennas faces numerous difficulties, partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities (circular polarization, pattern diversity, bandnotch operation), but also constraints imposed upon the physical size of the radiators. Conducting the design process at the level of fullwave electromagnetic (EM) simulations, otherwise...

DesignOriented TwoStage Surrogate Modeling of Miniaturized Microstrip Circuits with Dimensionality Reduction
PublikacjaContemporary microwave design heavily relies on fullwave electromagnetic (EM) simulation tools. This is especially the case for miniaturized devices where EM crosscoupling effects cannot be adequately accounted for using equivalent network models. Unfortunately, EM analysis incurs considerable computational expenses, which becomes a bottleneck whenever multiple evaluations are required. Common simulationbased design tasks include...

Reliable Surrogate Modeling of Antenna Input Characteristics by Means of Domain Confinement and Principal Components
PublikacjaA reliable design of contemporary antenna structures necessarily involves fullwave electromagnetic (EM) analysis which is the only tool capable of accounting, for example, for element coupling or the effects of connectors. As EM simulations tend to be CPUintensive, surrogate modeling allows for relieving the computational overhead of design tasks that require numerous analyses, for example, parametric optimization or uncertainty...

Uniform sampling in constrained domains for lowcost surrogate modeling of antenna input characteristics
PublikacjaIn this letter, a design of experiments technique that permits uniform sampling in constrained domains is proposed. The discussed method is applied to generate training data for construction of fast replacement models (surrogates) of antenna input characteristics. The modeling process is designoriented with the surrogate domain spanned by a set of reference designs optimized with respect to the performance figures and/or operating...

On Inadequacy of Sequential Design of Experiments for PerformanceDriven Surrogate Modeling of Antenna Input Characteristics
PublikacjaDesign of contemporary antennas necessarily involves electromagnetic (EM) simulation tools. Their employment is imperative to ensure evaluation reliability but also to carry out the design process itself, especially, the adjustment of antenna dimensions. For the latter, traditionally used parameter sweeping is more and more often replaced by rigorous numerical optimization, which entails considerable computational expenses, sometimes...

Editorial for the special issue on advances in forward and inverse surrogate modeling for highfrequency design
PublikacjaThe design of modern‐day high‐frequency devices and circuits, including microwave/RF, antenna and photonic components, historically has relied on full‐wave electromagnetic (EM) simulation tools. Initially used for design verification, EM simulations are nowadays used in the design process itself, for example, for finding optimum values of geometry and/or material parameters of the structures of interest. In a growing number of...

Surrogate modeling of impedance matching transformers by means of variable‐fidelity electromagnetic simulations and nested cokriging
PublikacjaAccurate performance evaluation of microwave components can be carried out using full‐wave electromagnetic (EM) simulation tools, routinely employed for circuit verification but also in the design process itself. Unfortunately, the computational cost of EM‐driven design may be high. This is especially pertinent to tasks entailing considerable number of simulations (eg, parametric optimization, statistical analysis). A possible...

Reliable lowcost surrogate modeling and design optimisation of antennas using implicit space mapping with substrate segmentation
PublikacjaAbstract: In this work, a reliable methodology for fast simulationdriven 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...

Reducedcost surrogate modeling of input characteristics and design optimization of dualband antennas using response features
PublikacjaIn this article, a procedure for lowcost surrogate modeling of input characteristics of dualband antennas has been discussed. The number of training data required for construction of an accurate model has been reduced by representing the antenna reflection response to the level of suitably defined feature points. The points are allocated to capture the critical features of the reflection characteristic, such as the frequencies...

Efficient Surrogate Modeling and Design Optimization of Compact Integrated OnChip Inductors Based on MultiFidelity EM Simulation Models
PublikacjaHighperformance and smallsize onchip inductors play a critical role in contemporary radiofrequency integrated circuits. This work presents a reliable surrogate modeling technique combining lowfidelity EM simulation models, response surface approximations based on kriging interpolation, and space mapping technology. The reported method is useful for the development of broadband and highly accurate datadriven models of integrated...

CostEfficient Surrogate Modeling of HighFrequency Structures Using Nested Kriging with Automated Adjustment of Model Domain Lateral Dimensions
PublikacjaSurrogate models are becoming popular tools of choice in mitigating issues related to the excessive cost of electromagnetic (EM)driven design of highfrequency structures. Among available techniques, approximation modeling is by far the most popular due to its versatility. In particular, the surrogates are exclusively based on the sampled simulation data with no need to involve engineering insight or problemspecific knowledge....

Improved Modeling of Microwave Structures Using PerformanceDriven FullyConnected Regression Surrogate
PublikacjaFast replacement models (or surrogates) have been widely applied in the recent years to accelerate simulationdriven design procedures in microwave engineering. The fundamental reason is a considerable—and often prohibitive—CPU cost of massive fullwave electromagnetic (EM) analyses related to solving common tasks such as parametric optimization or uncertainty quantification. The most popular class of surrogates are datadriven...

ReducedCost TwoLevel Surrogate Antenna Modeling using Domain Confinement and Response Features
PublikacjaElectromagnetic (EM) simulation tools have become indispensable in the design of contemporary antennas. Still, the major setback of EMdriven design is the associated computational overhead. This is because a single fullwave simulation may take from dozens of seconds up to several hours, thus, the cost of solving design tasks that involve multiple EM analyses may turn unmanageable. This is where faster system representations (surrogates)...

Adrian Bekasiewicz dr hab. inż.
OsobyAdrian Bekasiewicz received the MSc, PhD, and DSc degrees in electronic engineering from Gdansk University of Technology, Poland, in 2011, 2016, and 2020, respectively. In 2014, he joined Engineering Optimization & Modeling Center where he held a Research Associate and a Postdoctoral Fellow positions, respectively. Currently, he is an Associate Professor with Gdansk University of Technology, Poland. His research interests include...

DesignOriented Constrained Modeling of Antenna Structures
PublikacjaFast surrogate models are crucially important to reduce the cost of design process of antenna structures. Due to curse of dimensionality, standard (datadriven) modeling methods exhibit serious limitations concerning the number of independent geometry parameters that can be handled but also (and even more importantly) their parameter ranges. In this work, a designoriented modeling framework is proposed in which the surrogate is...

TwoStage VariableFidelity 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 fullwave 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. Performancedriven...

Rapid EMdriven antenna dimension scaling through inverse modeling
PublikacjaIn this letter, a computationally feasible technique for dimension scaling of antenna structures is introduced. The proposed methodology is based on inverse surrogate modeling where the geometry parameters of the antenna structure of interest are explicitly related to the operating frequency. The surrogate model is identified based on a few antenna designs optimized for selected reference frequencies. For the sake of computational...

CostEfficient BiLayer Modeling of Antenna Input Characteristics Using Gradient Kriging Surrogates
PublikacjaOver the recent years, surrogate modeling has been playing an increasing role in the design of antenna structures. The main incentive is to mitigate the issues related to high cost of electromagnetic (EM)based procedures. Among the various techniques, approximation surrogates are the most popular ones due to their flexibility and easy access. Notwithstanding, datadriven modeling of antenna characteristics is associated with serious...

Knowledgebased performancedriven modeling of antenna structures
PublikacjaThe importance of surrogate modeling techniques in the design of modern antenna systems has been continuously growing over the recent years. This phenomenon is a matter of practical necessity rather than simply a fashion. On the one hand, antenna design procedures rely on fullwave electromagnetic (EM) simulation tools. On the other hand, the computational costs incurred by repetitive EM analyses involved in solving common tasks...

Antenna Modeling Using VariableFidelity EM Simulations and Constrained CoKriging
PublikacjaUtilization of fast surrogate models has become a viable alternative to direct handling of fullwave electromagnetic (EM) simulations in EMdriven design. Their purpose is to alleviate the difficulties related to high computational cost of multiple simulations required by the common numerical procedures such as parametric optimization or uncertainty quantification. Yet, conventional datadriven (or approximation) modeling techniques...

Inverse surrogate models for fast geometry scaling of miniaturized dualband couplers
PublikacjaRedesign of microwave structures for various sets of performance specifications is a challenging task, particularly for compact components where considerable electromagnetic (EM) crosscouplings make the relationships between geometry parameters and the structure responses complex. Here, we address geometry scaling of miniaturized dualband couplers by means of inverse surrogate modeling. Our approach allows for fast estimation...

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 fullwave electromagnetic (EM) analysis of antenna systems. Although imperative in ensuring evaluation reliability, it entails considerable computational expenses. These are especially pronounced when carrying out EMdriven design tasks such...

Reliable computationallyefficient behavioral modeling of microwave passives using deep learning surrogates in confined domains
PublikacjaThe importance of surrogate modeling techniques has been steadily growing over the recent years in highfrequency electronics, including microwave engineering. Fast metamodels are employed to speedup design processes, especially those conducted at the level of fullwave electromagnetic (EM) simulations. The surrogates enable massive system evaluations at nearly EM accuracy and negligible costs, which is invaluable in parameter...

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 datadriven models valid over...

Reliable datadriven modeling of highfrequency structures by means of nested kriging with enhanced design of experiments
PublikacjaDatadriven (or approximation) surrogate models have been gaining popularity in many areas of engineering and science, including highfrequency electronics. They are attractive as a way of alleviating the difficulties pertinent to high computational cost of evaluating fullwave electromagnetic (EM) simulation models of microwave, antenna, and integrated photonic components and devices. Carrying out design tasks that involve massive...

Kriging Models for Microwave Filters
PublikacjaSurrogate modeling of microwave filters’ response is discussed. In particular, kriging is used to model either the scattering parameters of the filter or the rational representation of the filter’s characteristics. Surrogate models for these two variants of kriging are validated in solving a microwave filter optimization problem. A clear advantage of surrogate models based on the rational representation over the models based on scattering...

MultiFidelity Local Surrogate Model for Computationally Efficient Microwave Component Design Optimization
PublikacjaIn order to minimize the number of evaluations of highfidelity (“fine”) model in the optimization process, to increase the optimization speed, and to improve optimal solution accuracy, a robust and computationalefficient multifidelity local surrogatemodel optimization method is proposed. Based on the principle of response surface approximation, the proposed method exploits the multifidelity coarse models and polynomial interpolation...

PerformanceDriven Inverse/Forward Modeling of Antennas in VariableThickness Domains
PublikacjaDesign of contemporary antenna systems is a challenging endeavor. The difficulties are partially rooted in stringent specifications imposed on both electrical and field characteristics, demands concerning various functionalities, but also constraints imposed upon the physical size of the radiators. Furthermore, conducting the design process at the level of fullwave electromagnetic (EM) simulations, otherwise dictated by reliability,...

SimulationDriven Antenna Modeling by Means of Response Features and Confined Domains of Reduced Dimensionality
PublikacjaIn recent years, the employment of fullwave electromagnetic (EM) simulation tools has become imperative in the antenna design mainly for reliability reasons. While the CPU cost of a single simulation is rarely an issue, the computational overhead associated with EMdriven tasks that require massive EM analyses may become a serious bottleneck. A widely used approach to lessen this cost is the employment of surrogate models, especially...

Recent Advances in Accelerated MultiObjective Design of HighFrequency Structures using KnowledgeBased Constrained Modeling Approach
PublikacjaDesign automation, including reliable optimization of engineering systems, is of paramount importance for both academia and industry. This includes the design of highfrequency structures (antennas, microwave circuits, integrated photonic components), where the appropriate adjustment of geometry and material parameters is crucial to meet stringent performance requirements dictated by practical applications. Realistic design has...

Costefficient multiobjective design optimization of antennas in highlydimensional parameter spaces
PublikacjaMultiobjective optimization of antenna structures in highlydimensional parameter spaces is investigated. For expedited design, variablefidelity EM simulations and domain patching algorithm are utilized. The results obtained for a monopole antenna with 13 geometry parameters are compared with surrogateassisted optimization involving response surface approximation modeling.

Lowcost multicriterial design optimization of compact microwave passives using constrained surrogates and dimensionality reduction
PublikacjaDesign of contemporary microwave circuits is a challenging task. Typically, it has to take into account several performance requirements and constraints. The design objectives are often conflicting and their simultaneous improvement may not be possible; instead, compromise solutions are to be sought. Representative examples are miniaturized microwave passives where reduction of the circuit size has a detrimental effect on its electrical...