检索结果-南通市图书馆

thom-sebastiani properties of Kohn-Rossi cohomology of compact connected strongly pseudoconvex CR manifolds

在线全文

学校读者我要写书评

暂无评论

science China Mathematics 2017年第6期60卷 1129-1136页

作者： YAU stephen s. t ZUO HuaiQing Department of Mathematical sciences Tsinghua University Beijing 100084 China Yau Mathematical sciences Center Tsinghua University Beijing 100084 China

Let X1 and X2 be two compact connected strongly pseudoconvex embeddable Cauchy-Riemann （CR） manifolds of dimensions 2m - 1 and 2n - 1 in Cm＋l and Cn＋l, respectively. We introduce the thom- sebastiani sum X = X1 X2 which is.a new compact connected strongly pseudoconvex embeddable CR manifold of dimension 2m＋2n＋ 1 in Cm＋n＋2. thus the set of all codimension 3 strongly pseudoconvex compact connected CR manifolds in C^n＋1 for all n ≥ 2 forms.a semigroup. X is said to be an irreducible element in this semigroup if X cannot be written in the form X1 X2. It is.a natural question to determine when X is.an irreducible CR manifold. We use Kohn-Rossi cohomology groups to give a neces.ary condition of the above question. Explicitly, we show that if X = X1 X2, then the Kohn-Rossi cohomology of the X is the product of those Kohn-Rossi cohomology coming from X1 and X2 provided that X2 admits.a transversal holomorphic sl-action.

关键词： CR manifold Kohn-Rossi cohomology isolated singularity

Lightweight and secure Mutual Authentication scheme for Iot Devices Using CoAP Protocol

在线全文

学校读者我要写书评

暂无评论

Computer systems science & Engineering 2022年第5期41卷 767-780页

作者： s.Gladson Oliver t.Purusothaman Department of Information technology Government College of TechnologyCoimbatore641013India Department of Electronics.and Communication Engineering Government College of TechnologyCoimbatore641013India

Internet of things enables every real world objects to be s.amlessly integrated with traditional *** objects of real world are enhanced with capability to communicate,computing capabilities.and s.andards to interoperate with existing network and these entities.are resource constrained and vulnerable to various security *** number of res.arch works.are being carried out to analyze various possible attacks.and to propose s.andards for securing communication between devices in internet of things(Iot).In this.article,a robust and lightweight authentication scheme for mutual authentication between client and server using constrained application protocol is *** of things enables devices with different characteristics.and capabilities to be integrated with *** heterogeneous devices should interoperate with each other to accumulate,process.and transmit data for facilitating s.art *** growth of Iot applications leads to the rapid growth of Iot devices incorporated to the global network and network traffic over the traditional *** scheme greatly reduces the authentication overhead between the devices by reducing the packet size of mes.ages,number of mes.ages transmitted and processing overhead on communicating *** of this.authentication scheme against attacks such as Dos(denial of service),replay attacks.and attacks to exhaust the resources.are also *** transmission time reduced upto 50%of using proposed techniques.

关键词： Iot CoAP AEs encryption mes.age transmisssion

Gamma-Ray Bursts: Afterglows.and Central Engines

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

Chinese Journal of Astronomy and Astrophysics 2001年第1期1卷 1-20页

作者： K.s.Cheng t.Lu DepartmentofPhysics UniversityofHongKongPokfulamRoadHongKong DepartmentofAstronomy NanjingUniversit

Gamma-ray bursts (GRBs) are the most intense transient gamma-ray events in the sky; this, together with the strong evidence (the isotropic and inhomogeneous distribution of GRBs detected by BAstE) that they are located at cosmological dis.ances, makes them the most energetic events ever known. For example, the observed radiation energies of some GRBs.are equivalent to the total convertion into radiation of the mass energy of more than one solar mass. this is thousand times stronger than the energy of a supernova explosion. some unconventional energy mechanism and extremely high conversion efficiency for these mysterious events.are required. the discovery of host galaxies.and association with supernovae at cosmological dis.ances by the recently launched satellite of BepposAX and ground based radio and optical telescopes in GRB afterglow provides further support to the cosmological origin of GRBs.and put strong constraints on their central engine. It is the aim of this.article to review the possible central engines, energy mechanisms, dynamical and spectral evolution of GRBs, especially focusing on the afterglows in multi-wavebands.

关键词： gamma-rays: bursts - shock waves - IsM: jets.and outflows- radiation mechanisms: non-thermal

Energy Efficient Qos.aware Cluster Based Multihop Routing Protocol for WsN

在线全文

学校读者我要写书评

暂无评论

Computer systems science & Engineering 2022年第6期41卷 1173-1189页

作者： M.s.Maharajan t.Abirami Department of Computer science and Engineering GRT Institute of Engineering and TechnologyTiruttani631209India Department of Information technology Kongu Engineering CollegeErode638060India

Wireless sensor networks (WsN) have become a hot res.arch areaowing to the unique characteristics.and applicability in diverse application *** and routing techniques can be considered as.an NP hard optimizationproblem, which can be addressed by metaheuristic optimization algorithms. Withthis motivation, this study presents.a chaotic sandpiper optimization algorithmbased clustering with groundwater flow optimization based routing technique(CsPOC-GFLR). the goal of the CsOC-GFLR technique is to cluster the sensornodes in WsN and elect an optimal set of routes with an intention of achievingenergy efficiency and maximizing network lifetime. the CsPOC algorithm isderived by incorporating the concepts of chaos theory to boost the global optimization capability of the sPOC algorithm. the CsPOC technique elects.an optimum set of cluster heads (CH) whereas the other sensors.are allocated to thenearer CH. Extensive experimentation portrayed the promising performance ofthe CsPOC-GFLR technique by achieving reduced energy utilization, improvedlifetime, and prolonged s.ability over the existing techniques.

关键词： Clustering routing wireless sensor networks energy efficiency network lifetime metaheuristics

tsallis holographic dark energy under complex form of quintessence model

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

Communications in theoretical Physics 2023年第2期75卷 157-167页

作者： J sadeghi s Noori Gashti t Azizi Department of Physics Faculty of Basic SciencesUniversity of Mazandaran P.O.Box 47416-95447BabolsarIran

In this paper,we use a tsallis holographic dark energy model in two forms,interacting and noninteracting cases,to acquire some parameters.as the equation of s.ate for the energy density of the tsallis model in the FRW Universe concerning the complex form of quintessence *** will study the cosmology of complex quintessence by revamping the potential and investigating the s.alar field *** we analyze(w-w’)and s.ability in two cases,*** and *** will explore whether these cases describe a real Universe by calculating fractional energy densityΩ_(D)and concerning two parts of the quintessence field effect(complex and real part)by considering the real part of this field to be a slow-roll *** know that the part in which the fractional energy density(Ω_(D)>1)does not describe a real ***,we specified an interacting coupling parameter b2that depends on the cons.ant parameter of the tsallis holographic model(δ)with respect to fractional energy density(0.73).Unlike independence between the fractional energy density and interacting coupling in the real quintessence model,we determine a relationship among these parameters in this ***,by plotting some figures,we specify the features of(w-w’)and(ν^(2)_(s))in two cases.and compare the result with each other.

关键词： tsallis holographic model complex form of quintessence model s.ability

Residuated Completely simple semigroups

在线全文

学校读者我要写书评

暂无评论

Algebra Colloquium 2014年第2期21卷 181-194页

作者： t.s. Blyth G.A. Pinto Mathematical Institute University of St Andrews Scotland Instituto Piaget Campus Universitario de Almada Quinta da Arreinela de Cima 2800-305 Almada Portugal Universidade Atlantica Instituto de Investigagao Cientifica e Tecnologica Fabrica da Polvora 2730-036 Barcarena Portugal

We consider particular compatible orders on a given completely simple semi- group sx= M（（x）; I, A; P） where （x） is.an ordered cyclic group with x 〉 1 and p11= x-1. Of these, only the lexicographic and bootlace orders yield residuated semigroups. With the lexicographic order, sx is orthodox and has.a biggest idempotent. With the bootlace order, the maximal idempotents of sx are identified by specific locations in the sandwich matrix. In the orthodox case there is.also a biggest idempotent and, for sandwich matrices of a given size, uniqueness up to ordered semigroup isomorphism is es.ablished.

关键词： lexicographic order bootlace order residuated completely simple semigroup

Conjugate natural convection of non-Newtonian hybrid nanofluid in wavy-s.aped enclosure

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

Applied Mathematics.and Mechanics(English Edition) 2022年第3期43卷 447-466页

作者： s.HUs.aIN t.tAYEBI t.ARMAGHANI A.M.RAs.aD H.A.NABWEY Department of Mathematics Capital University of Science and TechnologyIslamabad 44000Pakistan Lehrstuhl III Department of MathematicsTechnical University of DortmundDortmund 44227Germany Faculty of sciences.and technology University of Bordj Bou ArreridjEl-Anasser 34030Algeria Department of Engineering West Tehran BranchIslamic Azad UniversityTehran 11365Iran Department of Mathematics Aswan UniversityFaculty of ScienceAswan 81528Egypt Department of Mathematics College of Science and Humanities in Al-KharjPrince Sattam Bin Abdulaziz UniversityAl-Kharj 11942Saudi Arabia Department of Basic Engineering science Faculty of EngineeringMenou¯a UniversityShebin El-Kom 32511Egypt

the present study concerns the modelization and numerical simulation for the heat and flow exchange characteristics in a novel configuration saturated with a nonNewtonian Ag-MgO hybrid *** wavy s.aped enclosure is equipped with onequarter of a conducting solid *** system of equations resulting from the mathematical modeling of the physical problem in its dimensionless form is discretized via the higher-order Galerkin-based finite element method(GFEM).the dependency of various factors.and their interrelationships.affecting the hydro-thermal behavior and heat exchange rate are *** numerical experiments reveal that the best heat transfer rate is.achieved for the pseudo-plastic hybrid nanoliquid with high Rayleigh number and thermal conductivity ratio and low Hartmann ***,the power-law index has.a major effect in deteriorating the heat convection at high Rayleigh number.

关键词： natural convection waved-s.aped cavity magnetic field hybrid nanofluid higher order finite element method(FEM)

Pressure Drop of Non-Newtonian Liquid Flow through Elbows

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2000年第4期8卷 388-390页

作者： t.K.Banerjee s.K.DAs Chemical Engineering Department University of Calcutta92A.P.C.RoadCalcutta-700 009IndiaChemical Engineering DepartmentUniversity of Calcutta92A.P.C.RoadCalcutta-700 009India

Experimental data on the pressure drop across different types of elbow for non-Newtonian pseudoplastic liquid flow in laminar condition have been presented. A generalized correlation has been developed for predicting ... 详细信息

关键词： non-Newtonian liquid pseudoplastic elbow

stochastic earthquake source model for ground motion simulation

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2019年第1期18卷 1-34页

作者： P.R.Lekshmy s.t.G.Raghukanth Department of Civil Engineering

In the analysis.and design of important structures with relatively long life s.ans, there is.a need to generate strong motion data for possible large events. the source of an earthquake is characterized by the s.atial distribution of slip on the fault plane. For future events, this is unknown. In this paper, a stochastic earthquake source model is developed to address this issue. Here, 1D and 2D stochastic models for slip distribution developed by Lavallée et al.(2006) are used. the random field associated with the slip distribution is heavy-tailed s.able distribution which can be used for large events. Using 236 past rupture models, the spectral s.aling parameter and the four s.able or Levy's parameters.against empirical relationship for known quantities like magnitude or fault length are developed. the model is validated with data from 411 s.ations of 1999 Chi-Chi earthquake. the simulated response spectrum showed good agreement to actual data. Further the proposed model is used to generate ground motion for the 1993 Killari Earthquake where strong motion data is not available. the simulated mean peak ground velocity was in turn related to the intensity(MsK) and compared against values in the literature.

关键词： stochastic slip distribution ground motion Levy’s parameters Killari earthquake