检索结果-南通市图书馆

Passive GNSS-based SAR imaging and opportunities using Galileo E5 signals

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2015年第6期58卷 84-94页

作者： MA Hui ANTONIOU Michail cherniakov mikhail School of Electronic and Information Engineering Beihang University Electronic Electrical and Systems Engineering Department University of Birmingham

This paper investigates the feasibility of Galileo navigation satellites as transmitters of opportunity in passive bistatic synthetic aperture radar(SAR) systems from the perspectives of signal processing and experiment program. Experimental images obtained using a single Galileo channel, E5 a or E5 b, are presented and analyzed. The paper also puts forward the channel combination scheme to jointly process E5 a and E5 b channels, which brings up high-resolution possibilities for passive SAR technique. By employing the entire E5 band for imaging, the range resolution may be potentially increased by up to 5 times. Preliminary experimental results for this concept are demonstrated.

关键词： bistatic synthetic aperture radar(BSAR) GNSS-based SAR Galileo E5 channel combination

Space-surface bistatic synthetic aperture radar with navigation satellite transmissions: a review

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2015年第6期58卷 5-24页

作者： ANTONIOU Michail cherniakov mikhail MA Hui Electronic Electrical and Systems Engineering Department University of Birmingham School of Electronic and Information Engineering Beihang University

This paper reviews the theory and practice of Space-Surface Bistatic Synthetic Aperture Radar(SS-BSAR) using navigation satellites as transmitters. In recent years, this innovative technology has reached a maturity stage which allows it to be considered for a wide range of applications. The paper covers the fundamental aspects of this technology as a radar system, such as the resolution, power budget and Point Spread Function(PSF) analysis, as well as its signal processing aspects and the state of the art in terms of advanced SAR techniques that it enables. Finally, the theoretical aspects of the paper may be directly transferred to the more generic SS-BSAR concept.

关键词： bistatic synthetic aperture radar GNSS-based SAR space-surface bistatic SAR coherent change detection multi-perspective imaging

GNSS-based BiSAR imaging using modified range migration algorithm

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2015年第8期58卷 144-156页

作者： ZENG Tao LIU FeiFeng ANTONIOU Michail cherniakov mikhail Beijing Key Laboratory of Embedded Real-time Information Processing Technology Beijing Institute of Technology School of Electronic Electrical and Systems Engineering University of Birmingham

This paper proposed a new focusing approach for the bistatic SAR systems with a GNSS(Global Navigation Satellite System) satellite as the transmitter. Because of the long integration time the inherited curvature of the transmitter’s trajectory was adopted and the spatial variance of the equivalent velocity was derived under the principal of equivalent slant range model in the system signal model. The proposed focusing approach consists of two-step processing. Firstly, the general Doppler phase from constant velocity of the echo data is focused by modified Stolt mapping. Secondly, the residual nonlinear Doppler phase due to velocity variation is compensated by means of block-processing-based adaptive phase compensation to achieve large scene focusing. The simulation and experimental results validate the proposed algorithm in GNSS-based Bi SAR systems.

关键词： GNSS-based Bi SAR equivalent slant range model curvature of trajectory two-step processing modified Stolt mapping

Ground moving target signal model and power calculation in forward scattering micro radar

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science in China(Series F) 2009年第9期52卷 1704-1714页

作者： LONG Teng HU Cheng mikhail cherniakov Radar Research Laboratory Department of Electronic Engineering Beijing Institute of Technology Beijing 100081 China Electronic Electrical and Computer Engineering Department of the University of Birmingham Edgbaston Birmingham B15 2TT UK

Forward scattering micro radar is used for situation awareness; its operational range is relatively short because of the battery power and local horizon, the free space propagation model is not appropriate. The ground moving targets, such as humans, cars and tanks, have only comparable size with the transmitted signal wavelength; the point target model and the linear change of observation angle are not applicable. In this paper, the signal model of ground moving target is developed based on the case of forward scattering micro radar, considering the two-ray propagation model and area target model, and nonlinear change of observation angle as well as high order phase error. Furthermore, the analytical form of the received power from moving target has been obtained. Using the simulated forward scattering radar cross section, the received power of theoretical calculation is near to that of measured data. In addition, the simulated signal model of ground moving target is perfectly matched with the experimented data. All these results show the correctness of analytical calculation completely.

关键词： forward scattering micro radar ground moving target signal model power calculation

An application of space-filling curves to improve results of turbulent aerodynamics modeling with convolutional neural networks

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2024年第2期37卷 81-92页

作者： mikhail PETROV Sofia ZIMINA Moscow Institute of Physics&Technology Dolgoprudny 141701Russia

When carrying out calculations for turbulent flow simulation,one inevitably has to face the choice between accuracy and speed of *** order to simultaneously obtain both a computationally efficient and more accurate model,a surrogate model can be built on the basis of some fast special model and knowledge of previous calculations obtained by more accurate base models from various test bases or some results of serial *** objective of this work is to construct a surrogate model which allows to improve the accuracy of turbulent calculations obtained by a special model on unstructured *** this purpose,we use 1D Convolutional Neural Network(CNN)of the encoder-decoder architecture and reduce the problem to a single dimension by applying space-filling *** an approach would have the benefit of being applicable to solutions obtained on unstructured *** this work,a non-local approach is applied where entire flow fields obtained by the special and base models are used as input and ground truth output ***-Allmaras(SA)model and Near-wall Domain Decomposition(NDD)method for SA are taken as the base and special models *** efficiency and accuracy of the obtained surrogate model are demonstrated in a case of supersonic flow over a compression corner with different values for angleαand Reynolds number *** conducted an investigation into interpolation and extrapolation by Re and also into interpolation byα.

关键词： Space-filling curves Convolutional neural network Domain decomposition Turbulent flows Unstructured mesh

Pricing Binary Variables of System-wide Constraints for Power System Optimization

在线全文

学校读者我要写书评

暂无评论

CSEE Journal of Power and Energy Systems 2024年第3期10卷 1131-1144页

作者： Jiaxun Li Wei Lin Zhifang Yang mikhail Davidson State Key Laboratory of Power Transmission Equipment and System Security and New Technology College of Electrical EngineeringChongqing UniversityChongqing 400030China Department of Electrical Engineering The Hong Kong Polytechnic UniversityHong Kong SAR 999077China Faculty of Computational Mathematics and Cybernetics Moscow State UniversityMoscow 119991Russia IEEE

With the trend of multiple energies or flexible demand in power systems,binary variables appear in systemwide constraints,which are the foundation of marginal pricing currently in *** appropriate pricing method incentivizes compliance of market participants;otherwise,compliance can be incentivized by paying discriminatory uplift payments which jeopardize transparency of *** paper proposes two theorems to examine whether the binary variables brought by multiple energies and flexible demand will impact compliance under marginal *** first theorem shows sufficient conditions with which marginal pricing with fixed binary variables incentivizes compliance,while the second theorem shows sufficient conditions to require uplift *** improve transparency by reducing uplift payments under cases which fall into the second theorem,this paper further proposes a pricing method by combining 1)designed constraints to price binary variables in system-wide constraints,and 2)convex hull pricing to price binary variables in private *** of the proposed theorems and pricing method is verified in an electricity-gas case(consisting of the IEEE 30-bus system and the NGS 10-node system)and the IEEE 118-bus test system.

关键词： Binary variables impact analysis pricing under non-convexities

A critical review on solid-state welding of high entropy alloys-processing,microstructural characteristics and mechanical properties of joints

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第4期34卷 78-133页

作者： Tushar Sonar mikhail Ivanov Evgeny Trofimov Aleksandr Tingaev Ilsiya Suleymanova Department of Welding Engineering Institution of Engineering and TechnologySouth Ural State University(National Research University)Chelyabinsk454080Russia Department of Materials Science Physical and Chemical Properties of MaterialsInstitution of Engineering and TechnologySouth Ural State University(National Research University)Chelyabinsk454080Russia

The high entropy alloys(HEAs)are the newly developed high-performance materials that have gained significant importance in defence,nuclear and aerospace sector due to their superior mechanical properties,heat resistance,high temperature strength and corrosion *** alloys are manufactured by the equal mixing or larger proportions of five or more alloying *** exhibit superior mechanical performance compared to traditional engineering alloys because of the extensive alloying composition and higher entropy of *** state welding(SSW)techniques such as friction stir welding(FSW),rotary friction welding(RFW),diffusion bonding(DB)and explosive welding(EW)have been efficiently deployed for improving the microstructural integrity and mechanical properties of welded HEA *** HEA interlayers revealed greater potential in supressing the formation of deleterious intermetallic phases and maximizing the mechanical properties of HEAs *** similar and dissimilar joining of HEAs has been manifested to be viable for HEA systems which further expands their industrial ***,the main objective of this review paper is to present a critical review of current state of research,challenges and opportunities and main directions in SSW of HEAs mainly CoCrFeNiMn and Al_xCoCrFeNi *** state of the art of problems,progress and future outlook in SSW of HEAs are critically reviewed by considering the formation of phases,microstructural evolution and mechanical properties of HEAs joints.

关键词： High entropy alloys Solid state welding Microstructure Mechanical properties

Numerical Analysis of Permeability of Functionally Graded Scaffolds

在线全文

学校读者我要写书评

暂无评论

Fluid Dynamics & Materials Processing 2024年第7期20卷 1463-1479页

作者： Dmitry Bratsun Natalia Elenskaya Ramil Siraev mikhail Tashkinov Laboratory of Mechanics of Biocompatible Materials and Devices Perm National Research Polytechnic UniversityPerm614990Russia

In this work,we numerically study the hydrodynamic permeability of new-generation artificial porous materials used as scaffolds for cell growth in a perfusion *** consider two popular solid matrix designs based on triply periodic minimal surfaces,the Schwarz P(primitive)and D(diamond)surfaces,which enable the creation of materials with controlled porosity *** latter property is crucial for regulating the shear stress field in the pores of the scaffold,which makes it possible to control the intensity of cell *** permeability of functionally graded materials is studied within the framework of both a microscopic approach based on the Navier-Stokes equation and an averaged description of the liquid filtration through a porous medium based on the equations of the Darcy or Forchheimer *** calculate the permeability coefficients for both types of solid matrices formed by Schwarz surfaces,study their properties concerning forward and reverse fluid flows,and determine the ranges of Reynolds number for which the description within the Darcy or Forchheimer model is ***,we obtain a shear stress field that varies along the sample,demonstrating the ability to tune spatially the rate of tissue growth.

关键词： Porous media ﬁltration models scaffolds functionally graded materials

Origin of iron-rich minerals,ooids and pisoids in the Jurassic ooidal ironstones of the Labino-Malkin region(Caucasus)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Palaeogeography 2024年第3期13卷 475-494页

作者： Natalia A.Kalinina Maxim A.Rudmin mikhail Sherstyukov Prokopiy Maximov Abdul-Gapur Kerimov Division for Geology School of Earth Sciences&EngineeringTomsk Polytechnic University634050TomskRussia Laboratory of Sedimentology and Paleobiosphere Evolution University of Tyumen625003 TyumenRussia Institute of Earth Science North-Caucasus Federal University355009StavropolRussia

This study investigates the Middle Jurassic rocks of the Labino-Malkin zone(Caucasus),represented by ooidal ironstones,biogenic limestones,and nodular *** rocks contain ooids/*** on the mineral composition,nine types of ooids and three possible scenarios for their formation have been *** mineral composition of ooids indicates the variable conditions of their deposition and repeated changes in physical and chemical conditions of the environment,including fluctuations in theredox *** access of oxygen in the bottom environment as a factor of increasing oxic conditions was associated with the regression of the sea and/or the inflow of meteoric *** main sources of ooids are the drift of material from the continent and convecting metal-bearing meteoric and/or deep solutions.

关键词： Ooidal ironstones Mineral formation Ooids Pisoids Mineral chemistry