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Performance evaluation of DHRR-RIS based HP design using machine learning algorithms

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Intelligent and Converged networks 2023年第3期4卷 237-260页

作者： girish Kumar n g Sree Ranga Raju m n the Department of Electronics and Telecommunication Engineering Bangalore Institute of TechnologyVisvesvaraya Technological UniversityBangalore 560004India the Department of Electronics and Communication Engineering Bangalore Institute of TechnologyVisvesvaraya Technological UniversityBangalore 560004India

Reconfigurable Intelligent Surfaces(RIS)have emerged as a promising technology for improving the reliability of massive mImO communication networks.However,conventional RIS suffer from poor Spectral Efficiency(SE)and high energy consumption,leading to complex Hybrid Precoding(HP)designs.To address these issues,we propose a new low-complexity HP model,named Dynamic Hybrid Relay Reflecting RIS based Hybrid Precoding(DHRR-RIS-HP).Our approach combines active and passive elements to cancel out the downsides of both conventional designs.We first design a DHRR-RIS and optimize the pilot and Channel State Information(CSI)estimation using an adaptive threshold method and Adaptive Back Propagation neural network(ABPnn)algorithm,respectively,to reduce the Bit Error Rate(BER)and energy consumption.To optimize the data stream,we cluster them into private and public streams using Enhanced Fuzzy C-means(EFCm)algorithm,and schedule them based on priority and emergency level.To maximize the sum rate and SE,we perform digital precoder optimization at the Base Station(BS)side using Deep Deterministic Policy gradient(DDPg)algorithm and analog precoder optimization at the DHRR-RIS using Fire Hawk Optimization(FHO)algorithm.We implement our proposed work using mATLAB R2020a and compare it with existing works using several validation metrics.Our results show that our proposed work outperforms existing works in terms of SE,Weighted Sum Rate(WSR),and BER.

关键词： Reconfigurable Intelligent Surfaces(RIS) Dynamic Hybrid Relay Reflecting(DHRR)-RIS multi User multiple Input multiple Output(mU-mImO) hybrid precoder machine learning and deep learning algorithms channel state estimation

modulational Instability of Optical Vortices in Engineered Saturable media

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Engineering 2022年第10期17卷 31-43页

作者： D.g.Pires n.m.Litchinitser Department of Electrical and Computer Engineering Duke UniversityDurhamNC 27708USA

Propagation of light beams in turbid media such as underwater environments,fog,clouds,or biological tissues finds increasingly important applications in science and technology,including bio-imaging,underwater communication,and free-space communication technologies.While many of these applications traditionally relied on conventional,linearly polarized gaussian beams,light possesses many degrees of freedom that are still largely unexplored,such as spin angular momentum(SAm)and orbital angular momentum(OAm).Here,we present nonlinear light-matter interactions of such complex light beams with"rotational"degrees of freedom in engineered nonlinear colloidal media.By making use of both variational and perturbative approach,we consider non-cylindrical optical vortices,elliptical optical vortices,and higher-order Bessel beams integrated in time(HOBBIT)to predict the dynamics and stability of the evolution of these beams.These results may find applications in many scenarios involving light transmission in strongly scattering environments.

关键词： Optical vortex Orbital angular momentum modulation instability Turbid media

Efficient antibody evasion but reduced ACE2 binding by the emerging SARS-CoV-2 variant B.1.640.2

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Cellular & molecular Immunology 2022年第9期19卷 1067-1069页

作者： Prerna Arora Amy Kempf Inga nehlmeier Luise graichen Sebastian Schulz Anne Cossmann Alexandra Dopfer-Jablonka martin S.Winkler Hans-martin Jäck georG.M.N.Behrens Stefan Pöhlmann markus Hoffmann Infection Biology Unit German Primate CenterKellnerweg 437077GöttingenGermany Faculty of Biology and Psychology Georg-August-University GöttingenWilhelmsplatz 137073GöttingenGermany Division of molecular Immunology Department of Internal Medicine 3Friedrich-Alexander University of Erlangen-NürnbergGlückstraße 691054ErlangenGermany Department for Rheumatology and Immunology Hannover Medical SchoolCarl-Neuberg-Straße 130625HannoverGermany german Centre for Infection Research(DZIF) Partner Site Hannover-BraunschweigHannoverGermany Centre for Individualised Infection medicine(Ciim) HannoverGermany Department of Anesthesiology University of Göttingen Medical CenterGöttingenGeorg-August University of GöttingenRobert-Koch-Straße 4037075GöttingenGermany

The SARS-CoV-2 spike(S)protein engages ACE2 for cell entry,and the S protein/ACE2 interface is an important target for neutralizing antibodies.In the course of the COVID-19 pandemic,SARS-CoV-2 variants have emerged that harbor mutations in the S protein,which confer neutralization resistance and allow viral spread in immunologically nonnaive populations.The most prominent example is the highly mutated Omicron variant,which infects convalescent or vaccinated individuals with unprecedented efficiency[1,2].

关键词： ACE2 harbor neutral

Investigation of the ^(121)Sb(α,γ)^(125)I reaction cross-section calculations at astrophysical energies

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nuclear Science and Techniques 2023年第11期34卷 85-92页

作者： m.Eroğlu C.Yalcın R.T.güray Department of Physics Kocaeli UniversityUmuttepe41001 KocaeliTurkey Department of Electronics and Automation Piri Reis University34940 TuzlaIstanbulTurkey

Proton-rich nuclei are synthesized via photodisintegration and reverse reactions.To examine this mechanism and reproduce the observed p-nucleus abundances,it is crucial to know the reaction rates and thereby the reaction cross sections of many isotopes.given that the number of experiments on the reactions in astrophysical energy regions is very rare,the reaction cross sections are determined by theoretical methods whose accuracy should be tested.In this study,given that ^(121)Sb is a stable seed isotope located in the region of medium-mass p-nuclei,we investigated the cross sections and reaction rates of the ^(121)Sb(α,γ)^(125)I reaction using the TALYS computer code with 432 different combinations of input parameters(OmP,LDm,and SFm).The optimal model combinations were determined using the threshold logic unit method.The theoretical reaction cross-sectional results were compared with the experimental results reported in the literature.The reaction rates were determined using the two input parameter sets most compatible with the measurements,and they were compared with the reaction rate databases:STARLIB and REACLIB.

关键词： Cross section Astrophysical S-factor Astrophysical reaction rate p-process nucleosynthesis Threshold logic unit method

multi criteria decision making through TOPSIS and COPRAS on drilling parameters of magnesium AZ91

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Journal of magnesium and Alloys 2022年第10期10卷 2857-2874页

作者： m.Varatharajulu muthukannan Duraiselvam m.Bhuvanesh Kumar g.Jayaprakashc n.Baskar Department of Production Engineering National Institute of TechnologyTiruchirappalli 620015TamilnaduIndia Department of mechanical Engineering A.V.C.College of EngineeringMannampandal609305TamilnaduIndia Department of mechanical Engineering Saranathan College of EngineeringTiruchirapalli 620012TamilnaduIndia Department of mechanical Engineering Kongu Engineering CollegePerundurai 638060TamilnaduIndia

magnesium(mg)alloys are extensively used in the automotive and aircraft industries due to their prominent properties.The selection of appropriate process parameters is an important decision to be made because of the cost reduction and quality improvement.This decision entails the selection of suitable process parameters concerning various conflicting factors,so it has to be addressed with the multiple Criteria Decision making(mCDm)method.Therefore,this work addresses the mCDm problem through the TOPSIS(Technique for Order Preference by Similarity to Ideal Solution)and COPRAS(COmplex PRoportional ASsessment)methods.The assessment carried out in the material mg AZ91 with the Solid Carbide(SC)drill bit.The dependent parameters like drilling time,burr height,burr thickness,and roughness are considered with the independent parameters like spindle speed and feed rate.Drilling alternatives are ranked using the above said two methods and the results are evaluated.The optimum combination was found on the basis of TOPSIS and COPRAS for simultaneous minimization of all the responses which is found with a spindle speed of 4540 rpm and a feed rate of 0.076 mm/rev.The identical sequencing order was observed in TOPSIS and COPRAS method.The empirical model was developed through Box-Behnken design for each response.Superior empirical model developed for drilling time which is 3.959 times accurate than the conventional equation.The trends of various dependents based on the heterogeneity of various independents are not identical,these complex mechanisms are identified and reported.The optimized results of the Desirability Function Approach are greater accordance with the TOPSIS and COPRAS top rank.The confirmation results are observed with lesser deviation suggesting the selection of the above independent parameters.

关键词： machining processes magnesium TOPSIS COPRAS mCDm Burr Roughness

mean-Square Approximation of navier-Stokes Equations with Additive noise in Vorticity-Velocity Formulation

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numerical mathematics(Theory,methods and Applications) 2021年第1期14卷 1-30页

作者： g.n.milstein m.V.Tretyakov Ural Federal University EkaterinburgRussia School of mathematical Sciences University of NottinghamNottinghamUK

We consider a time discretization of incompressible navier-Stokes equations with spatial periodic boundary conditions and additive noise in the vorticity-velocity formulation.The approximation is based on freezing the velocity on time subintervals resulting in a linear stochastic parabolic equation for vorticity.At each time step,the velocity is expressed via vorticity using a formula corresponding to the Biot-Savart-type law.We prove the first mean-square convergence order of the vorticity approximation.

关键词： navier-Stokes equations vorticity numerical method stochastic partial differential equations mean-square convergence

酸浸法和溶剂萃取法分离提纯Kola Peninsula铅细晶矿中的钽

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Journal of Central South University 2021年第1期28卷 72-88页

作者： S m mASLOBOEVA L g ARUTYUnYAn m n PALATnIKOV D V mAnUKOVSKAYA Tananaev Institute of Chemistry–Subdivision of the Federal Research Centre Kola Science Centre of the Russian Academy of SciencesApatity 184209Russia

采用了氢氟酸和硫酸、氢氟酸和硝酸的混合酸浸出法,对铅细晶矿进行了浸取分离。在最佳条件下,钽和铌的收率达到99%,同时并确保放射性核素留在不溶性残渣中。提出了采用氟酸-硫酸和氟酸-硝酸萃取分离钽与铌、铅和杂质的浸出方案,并生产... 详细信息

采用了氢氟酸和硫酸、氢氟酸和硝酸的混合酸浸出法,对铅细晶矿进行了浸取分离。在最佳条件下,钽和铌的收率达到99%,同时并确保放射性核素留在不溶性残渣中。提出了采用氟酸-硫酸和氟酸-硝酸萃取分离钽与铌、铅和杂质的浸出方案,并生产高纯钽化合物。确定了辛醇-1作为萃取剂,反萃生产高纯钽的各阶段萃取-洗涤-反萃的最佳条件。生产出的钽化合物,如五氧化二钽和七氟戊二酸钾,杂质含量符合高纯物质的标准。

关键词：铅细晶石钽铌酸浸法放射性溶剂萃取

mathematical modeling of Biological Fluid Flow Through a Cylindrical Layer with Due Account for Barodiffusion

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Communications on Applied mathematics and Computation 2023年第4期5卷 1365-1384页

作者： n.n.nazarenko A.g.Knyazeva Institute of Strength Physics and materials Science Siberian Branch of the Russian Academy of SciencesTomsk634021Russia

The work proposes a model of biological fluid flow in a steady mode through a cylindrical layer taking into account convection and diffusion.The model considers finite compressibility and concentration expansion connected with both barodiffusion and additional mechanism of pressure change in the pore volume due to the concentration gradient.Thus,the model is entirely coupled.The paper highlights the complexes composed of scales of physical quantities of different natures.The iteration algorithm for the numerical solution of the problem was developed for the coupled problem.The work involves numerical studies of the considered effects on the characteristics of the flow that can be convective or diffusive,depending on the relation between the dimensionless complexes.It is demonstrated that the distribution of velocity and concentration for different cylinder wall thicknesses is different.It is established that the barodiffusion has a considerable impact on the process in the convective mode or in the case of reduced cylinder wall thickness.

关键词： Filtration Diffusion Convective and diffusive flow regimes Barodiffusion

Sintering behavior of combusted iron powder in a packed bed reactor with nitrogen and hydrogen

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Particuology 2023年第12期83卷 8-17页

作者： C.J.m.Hessels A.H.J.Smeets g.Finotello n.g.Deen Y.Tang Power and Flow group Department of Mechanical EngineeringEindhoven University of TechnologyPO Box 5135600MBEindhoventhe Netherlands Eindhoven Institute for Renewable Energy Systems(EIRES) PO Box 5135600MBEindhoventhe Netherlands

Sintering behavior of micron-sized combusted iron powder is studied in a packed bed reactor,at various temperatures under inert(nitrogen)and reducing(hydrogen)conditions.Compression tests are subsequently used to quantify the degree of sintering.A sintering model,based on the formation of a solid bridge through solid state surface diffusion of iron atoms,matches the experimental results.Sintering of combusted iron occurs at temperatures≥575°C in both nitrogen and hydrogen atmospheres and increases exponentially with temperature.The observed decrease in reduction rate at high temperatures is not caused by the sintering process but by the formation of wüstite as an intermediate species,leading to the formation of a dense iron layer.Iron whiskers form at high temperatures(≥700°C)in combination with low reduction rates(≤25 vol%H2),leading to the production of sub-micron fines.

关键词： metal energy carrier Combusted iron Whiskers Solid bridge force Sintering