Variable-fidelity electromagnetic simulations and co-kriging for accurate modeling of antennas

Accurate and fast models are indispensable in contemporary antenna design. In this paper, we describe the low-cost antenna modeling methodology involving variable-fidelity electromagnetic (EM) simulations and co-Kriging. Our approach exploits sparsely sampled accurate (high-fidelity) EM data as well as densely sampled coarse-discretization (low-fidelity) EM simulations that are accommodated into one model using the co-Kriging technique. By using coarse-discretization simulations, the computational cost of creating the antenna model is greatly reduced compared to conventional approaches, where high-fidelity simulations are directly used to set up the model. At the same time, the modeling accuracy is not compromised. The proposed technique is demonstrated using three examples of antenna structures. Comparisons with conventional modeling based on high-fidelity data approximation, as well as applications for antenna design, are also discussed

Multi-objective design of antenna structures using variable-fidelity EM simulations and co-kriging

A methodology for low-cost multi-objective design of antenna structures is proposed. To reduce the computational effort of the design process the initial Pareto front is obtained by optimizing the response surface approximation (RSA) model obtained from low-fidelity EM simulations of the antenna structure of interest. The front is further refined by iterative incorporation of a limited number of high-fidelity training points into the RSA surrogate using co-kriging. Our considerations are illustrated using two examples of antenna structure

ОБҐРУНТУВАННЯ ДАНИХ ДЛЯ МОДЕЛЮВАННЯ ПОЖЕЖ ЛЕГКОВИХ АВТОМОБІЛІВ У ПІДЗЕМНИХ ОБ’ЄКТАХ АВТОТРАНСПОРТНОЇ ІНФРАСТРУКТУРИ

The article presents the results of analytical studies of the dynamics and parameters of car fires, which can be used during their mathematical modelling in underground units of transportation infrastructure. Data on the thermal capacity of the seat of car fires, and its changes over time are generalized. It is proposed to use a geometric shape of seat of fire during modelling as approximate to a real car fire with the details of certain items taking account the size of a cell of computing domain.У статті наводяться результати аналітичних досліджень динаміки та параметрів горіння легкових автомобілів, які можуть бути використані при проведенні математичного моделювання пожеж у підземних об’єктах автотранспортної інфраструктури. Узагальнені дані щодо теплової потужності вогнища пожежі легкового автомобіля, закономірностей зміни її в часі. Запропоновано приймати геометричну форму вогнища пожежі при проведенні моделювання, як наближену до вигляду реального автомобіля із деталізацією його окремих елементів з урахуванням розмірів комірки обчислювального домен

Computationally efficient multi-fidelity Bayesian support vector regression modeling of planar antenna input characteristics

Bayesian support vector regression (BSVR) modeling of planar antennas with reduced training sets for computational efficiency is presented. Coarse-discretization electromagnetic (EM) simulations are exploited in order to find a reduced number of fine-discretization training points for establishing a high-fidelity BSVR model of the antenna. As demonstrated using three planar antennas with different response types, the proposed technique allows substantial reduction (up to 48%) of the computational effort necessary to set up the fine-discretization training data sets for the high-fidelity models with negligible loss in predictive power. The accuracy of the reduced-data BSVR models is confirmed by their successful use within a space mapping optimization/design algorithm.http://ieeexplore.ieee.org/xpl/RecentIssue.jsp?punumber=8hb2016Electrical, Electronic and Computer Engineerin

Distinct Patterns of Expression and Evolution of Intronless and Intron-Containing Mammalian Genes

Comparison of expression levels and breadth and evolutionary rates of intronless and intron-containing mammalian genes shows that intronless genes are expressed at lower levels, tend to be tissue specific, and evolve significantly faster than spliced genes. By contrast, monomorphic spliced genes that are not subject to detectable alternative splicing and polymorphic alternatively spliced genes show similar statistically indistinguishable patterns of expression and evolution. Alternative splicing is most common in ancient genes, whereas intronless genes appear to have relatively recent origins. These results imply tight coupling between different stages of gene expression, in particular, transcription, splicing, and nucleocytosolic transport of transcripts, and suggest that formation of intronless genes is an important route of evolution of novel tissue-specific functions in animals