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DYNAMIC RESPONSE OF ELASTIC LAYER ON STIFF FOUNDATION UNDER TIME HARMONIC SURFACE VERTICAL CONCENTRATED LOAD

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Applied Mathematics and Mechanics(English Edition) 1987年第10期8卷 919-927页

作者：郑健龙 Changsha Changsha communications institute

In lhis paper,the line-load integral equation method proposed in reference[1] is firstused for solving the elastodynamic problems.A set of one-dimensional regular integralequation is derived for calculating the dynamic response of elastic layer on stiff foundationunder time harmonic surface vertical concentraled load And the numerical solution of theintegral equation is obtained.

关键词： exp In 一彻 DYNAMIC RESPONSE OF ELASTIC LAYER ON STIFF FOUNDATION UNDER TIME HARMONIC SURFACE VERTICAL CONCENTRATED LOAD

Stretch-Minimizing Volumetric Parameterization

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Journal of Computer Science & Technology 2015年第3期30卷 553-564页

作者：金耀钱归平赵杰伊常建童若锋张建军 Department of Computer Science and Engineering Zhejiang University Hangzhou 310027 China College of New media Zhejiang University of Media and Communications Hangzhou 310018 China National Centre for Computer Animation Bournemouth University Bournemouth BH12 5BB U.K.

Not many methods for parameterization guarantee bijectivity or local injectivity, which is essential for foldover- free mappings. Stretch-minimizing parameterization which is widely used for surface parameterization, provides foldover-free mappings and is capable of trading off between angle and area distortions. We extend its usage to volumetric parameterization in this paper by deriving a 3D version of stretch-distortion energy and incorporating fixed boundary conditions. Our energy definition includes a naturM barrier term which effectively prevents elements from collapsing and folding over. It saves the effort in other methods of formulating additional energy or constrains to ensure the local injectivity. We propose to minimize the overall energy integrated over the whole mesh with a relaxation-enhanced solver and optimize the energy globally. This is different from the conventional approach of surface parameterization where mesh nodes are optimized individually. Compared with other volumetric parameterizations, method, being foldover-free and offering a good trade-off between our approach bears the advantages of stretch-minimizing angle and volume distortions.

关键词： stretch-minimizing volumetric parameterization foldover-free

Lower bounds on the periodic Hamming correlations of frequency hopping sequences with low hit zone

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Science in China(Series F) 2006年第2期49卷 208-218页

作者： PENG Daiyuan FAN Pingzhi LEE Moon Ho institute of Mobile communications Southwest Jiaotong University Chengdu 610031 China institute of Information and communications Chonbuk National University.Jeonju 560-756 Korea

In this paper, several periodic Hamming correlation lower bounds for frequency hopping sequences with low hit zone, with respect to the size p of the frequency slot set, the sequence length L, the family size M, low hit zone LH （ or no hit zone NH ）, the maximum periodic Hamming autocorrelation sidelobe Ha and the maximum periodic Hamming crosscorrelation He, are established. It is shown that the new bounds include the known LempeI-Greenberger bounds, T.S. Seay bounds and Peng-Fan bounds for the conventional frequency hopping sequences as special cases.

关键词： frequency hopping sequences Hamming correlation Lempel-Greenberger bounds low hit zone,lower bounds no hit zone.

Building an interoperable space for smart agriculture

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Digital communications and Networks 2023年第1期9卷 183-193页

作者： Ioanna Roussaki Kevin Doolin Antonio Skarmeta George Routis Juan Antonio Lopez-Morales Ethel Claffey Manuel Mora Juan Antonio Martinez institute of communications and Computer Systems AthensGreece Walton institute WaterfordIreland Department of Information and communications Engineering University of MurciaMurciaSpain School of Business Waterford Institute of TechnologyWaterfordIreland R&D Department Odin SolutionsMurciaSpain

The digital transformation in agriculture introduces new challenges in terms of data,knowledge and technology adoption due to critical interoperability issues,and also challenges regarding the identification of the most suitable data sources to be exploited and the information models that must be ***(Building an Interoperable,Data-Driven,Innovative and Sustainable European Agri-Food Sector)addresses these challenges by providing an overarching solution that integrates various heterogeneous hardware and software resources(e.g.,devices,networks,platforms)and enables the seamless sharing of data and knowledge throughout the agri-food *** paper introduces the main concepts of DEMETER and its reference architecture to address the data sharing and interoperability needs of farmers,which is validated via two rounds of 20 large-scale pilots along the DEMETER *** paper elaborates on the two pilots carried out in region of Murcia in Spain,which target the arable crops sector and demonstrate the benefits of the deployed DEMETER reference architecture.

关键词： Smart agriculture Internet of things(IoT) DEMETER Reference architecture Interoperability Agricultural information model(AIM) Pilot validation

A Higher-Efficient Three-Dimensional Numerical Model for Small Amplitude Free Surface Flows

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China Ocean Engineering 2014年第5期28卷 617-628页

作者：吕彪 Key Laboratory of Engineering Sediment of Ministry of communications Tianjin Research Institute for Water Transport Engineering

A higher-efficient three-dimensional non-hydrostatic model is developed to simulate small amplitude free surface flows based on a staggered unstructured grid. In this model, a fractional step algorithm is adopted to solve the Navier-Stokes equations in two major steps. A top-layer pressure method is proposed to minimize the number of vertical layers and subsequently the computational cost. Three classical examples of small amplitude free surface flows are used to demonstrate the capability and efficiency of the model. The satisfactory results demonstrated the capability and efficiency of modelling a range of small amplitude free surface flows with only a small number of vertical layers.

关键词： higher-efficient non-hydrostatic small amplitude free surface flows 3D numerical model

A Lightweight ABE Security Protection Scheme in Cloud Environment Based on Attribute Weight

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Computers, Materials & Continua 2023年第8期76卷 1929-1946页

作者： Lihong Guo Jie Yang Haitao Wu Department of Information and communications Engineering Nanjing Institute of TechnologyNanjing211167China

Attribute-based encryption(ABE)is a technique used to encrypt data,it has the flexibility of access control,high security,and resistance to collusion attacks,and especially it is used in cloud security ***,a large number of bilinear mappings are used in ABE,and the calculation of bilinear pairing is *** there is the problem of low *** the other hand,the decryption key is not uniquely associated with personal identification information,if the decryption key is maliciously sold,ABE is unable to achieve accountability for the *** practical applications,shared message requires hierarchical sharing in most cases,in this paper,we present a message security hierarchy ABE scheme for this ***,attributes were grouped and weighted according to the importance of attributes,and then an access structure based on a threshold tree was constructed according to attribute *** method saved the computing time for decryption while ensuring security and on-demand access to information for *** addition,with the help of computing power in the cloud,two-step decryption was used to complete the access,which relieved the computing and storage burden on the client ***,we simulated and tested the scheme based on CP-ABE,and selected different security levels to test its *** security proof and the experimental simulation result showthat the proposed scheme has high efficiency and good performance,and the solution implements hierarchical access to the shared message.

关键词： Attribute-based encryption cloud security message hierarchy attribute weight access control

A New Efficient Finite Volume Modeling of Small Amplitude Free Surface Flows with Unstructured Grid

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China Ocean Engineering 2013年第4期27卷 509-522页

作者：吕彪 Key Laboratory of Engineering Sediment of Ministry of communications Tianjin Research Institute for Water Transport Engineering

A staggered finite-volume technique for non-hydrostatic, small amplitude free surface flow governed by the incompressible Navier-Stokes equations is presented there is a proper balance between accuracy and computing time. The advection and horizontal diffusion terms in the momentum equation are discretized by an integral interpolation method on the orthogonal unstructured staggered mesh and, while it has the attractive property of being conservative. The pressure-correction algorithm is employed for the non-hydrostatic pressure in order to achieve second-order temporal accuracy. A conservative scalar transport algorithm is also applied to discretize k - c equations in this model. The eddy viscosity is calculated from the k-c turbulent model. The resulting model is mass and momentum conservative. The model is verified by two examples to simulate unsteady small amplitude free surface flows where non-hydrostatic pressures have a considerable effect on the velocity field, and then applied to simulate the tidal flow in the Bohai Sea.

关键词： orthogonal unstructured grid non-hydrostatic small amplitude free surface flows 3-D numerical model k - ~ turbulent model

CHAOS OF LIQUID SURFACE WAVES IN A VESSEL UNDER VERTICAL EXCITATION WITH SLOWLY MODULATED AMPLITUDE

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Acta Mechanica Sinica 1997年第2期13卷 106-112页

作者：何国威李家春 Laboratory for Nonlinear Mechanics of Continuous media Institute of MechanicsChinese Academy of SciencesBeijing 100080China

Free surface waves in a cylinder of liquid under vertical excitation with slowly modulated amplitude are investigated in the current paper. It is shown by both theoretical analysis and numerical simulation that chaos may occur even for a single mode with modulation which can be used to explain Gollub and Meyer's experiment. The implied resonant mechanism accounting for this phenomenon is further elucidated.

关键词： Faraday experiment chaos resonant interaction

Feature-based Image Sequence Compression Coding

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High Technology Letters 2001年第2期7卷 31-33页

作者：周志权 Jia Shilou Department of Electronics and communications Engineering Harbin Institute of Technology

A novel compressing method for video teleconference applications is presented. Semantic-based coding based on human image feature is realized, where human features are adopted as parameters. Model-based coding and the... 详细信息

关键词： Compression coding Model-based Feature-based