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On application of the Stochastic Finite Volume Method in Navier-Stokes problems
No full textThe main aim of this article is numerical solution of the fully coupled Navier-Stokes equations with Gaussian random parameters. It is provided thanks to the specially adopted Finite Volume Method, modified using the generalized stochastic perturbation technique. This Stochastic Finite Volume Method is applied to model 3D problem with uncertainty in liquid viscosity and a coefficient of the heat conduction, separately. Probabilistic moments and characteristics of up to the fourth order are determined with the use of the Response Function Method realized numerically via the polynomial inpterpolation. Although mathematical formulation of the SFVM has been proposed in addition to the problems including single random variable, it is possible to extend it towards multi-parametric cases, also for the correlated random variables. Inclusion of the boundary conditions in both global and local sense is quite straightforward but needs some prior experimental basic statistics
Size-Dependent Behavior of Macromolecular Solids III: The Role of Entanglements
No full textChain rotations in macromolecular solids are constrained by entanglements. The effects of constraints on strain deformation and strain gradient deformation were investigated using molecular dynamic (MD) simulation in this paper. The effects on the chains were examined by embedding the chains inside bent beams. For thick beams, the simulated elastic moduli for styrene butyl rubber (SBR), polyimide (PI) and polyethylene (PE) were in good agreement with elastic moduli reported in the literature. The elastic moduli varied linearly with entanglements and inversely with the molecular weight. For thin beams where strain gradients were non-negligible, the results showed that l2, the higher order rotational length scale material parameter, also varied linearly with entanglements and inversely with the molecular weight. The linear dependence of E0 and l2 on entanglements can be correlated within specific chemistry such that the size dependent behavior of solids with the same monomer, but different molecular weight and entanglement can be predicted from the correlations. However, the correlations are chemistry specific, and the size-dependent behavior for a macromolecular solid cannot be casually predicted from the size-dependent behavior of another solid
Load Test and Fatigue Life Evaluation for Welded Details in Taizhou Yangtze River Bridge
Get PDFTo study the fatigue performance of welded details in the orthotropic steel decks, the steel box girder for Taizhou Yangtze River Bridge is taken as the research object. Based on the field monitoring data obtained from the load test, the stress response test of the orthotropic steel box girder under wheel loads is performed and the correctness of the vehicle test data obtained from the field monitoring data also have been verified by the numerical results of the finite element model. Based on the Miner linear cumulative damage theory, the S-N curve of the Eurocode3 specification is referenced, and the fatigue life calculation formula of the welded details is determined according to the actual structural features. The fatigue life evaluation of the four typical welded details is obtained. The results indicate that: The load test data is compared and verified by the numerical result of finite element model. The local effect of stress distribution is remarkable. The stress measurement points on the four typical welded details are mainly based on low amplitude stress cycles. Most of the stress ranges are 2-10 MPa, among which the stress range of the welded details at the U-rib butt joint is larger. The fatigue life of welded details in the 14 mm thick top plate is smaller than that of the 16 mm thick top plate corresponding to the fatigue life of the welded details. The rib-to-rib butt welded joints and the openings of the diaphragms were prone to fatigue failure. Among them, the welding details of the 14 mm thick U-rib butt joints first appeared fatigue failure. The arrangement of the diaphragm can effectively increase the fatigue life of the top-U rib weld and improve the fatigue performance at this detail
An Ui Design Optimization Strategy for General App in Big Data Environment
Get PDFDue to the huge amount of increasing data, the requirements of people for electronic products such as mobile phones, tablets, and notebooks are constantly improving. The development and design of various software applications attach great importance to users’ experiences. The rationalized UI design should allow a user not only enjoy the visual design experience of the new product but also operating it more pleasingly. This process is to enhance the attractiveness and performance of the new product and thus to promote the active usage and consuming conduct of users. In this paper, an UI design optimization strategy for general APP in the big data environment is proposed to get better user experience while effectively obtaining information. An experimental example of a library APP is designed to optimize the user experience. The experimental results show that the user-centered UI design is the core of optimization, and user portrait based on big data platforms is the key to UI design
Quantum Multi-User Detection Based on Coherent State Signals
Get PDFMulti-user detection is one of the important technical problems for modern communications. In the field of quantum communication, the multi-access channel on which we apply the technology of quantum information processing is still an open question. In this work, we investigate the multi-user detection problem based on the binary coherent-state signals whose communication way is supposed to be seen as a quantum channel. A binary phase shift keying model of this multi-access channel is studied and a novel method of quantum detection proposed according to the conclusion of the quantum measurement theory. As a result, the average interference between deferent users is presented and the average error probability of the quantum detection is derived theoretically. Finally, we show the maximum channel capacity of this effective detection for a two-access quantum channe
Ground-Based Cloud Recognition Based on Dense_SIFT Features
Get PDFClouds play an important role in modulating radiation processes and climate changes in the Earth's atmosphere. Currently, measurement of meteorological elements such as temperature, air pressure, humidity, and wind has been automated. However, the cloud's automatic identification technology is still not perfect. Thus, this paper presents an approach that extracts dense scale-invariant feature transform (Dense_SIFT) as the local features of four typical cloud images. The extracted cloud features are then clustered by K-means algorithm, and the bag-of-words (BoW) model is used to describe each ground-based cloud image. Finally, support vector machine (SVM) is used for classification and recognition. Based on this design, a nephogram recognition intelligent application is implemented. Experiments show that, compared with other classifiers, our approach has better performance and achieved a recognition rate of 88.1%
Overview of Digital Image Restoration
Get PDFImage restoration is an image processing technology with great practical value in the field of computer vision. It is a computer technology that estimates the image information of the damaged area according to the residual image information of the damaged image and carries out automatic repair. This article firstly classify and summarize image restoration algorithms, and describe recent advances in the research respectively from three aspects including image restoration based on partial differential equation, based on the texture of image restoration and based on deep learning, then make the brief analysis of digital image restoration of subjective and objective evaluation method, and briefly summarize application of digital image restoration technique in the future and prospects, provide direction for the research on image after repair
Multi-Label Chinese Comments Categorization: Comparison of Multi-Label Learning Algorithms
Get PDFMulti-label text categorization refers to the problem of categorizing text through a multi-label learning algorithm. Text classification for Asian languages such as Chinese is different from work for other languages such as English which use spaces to separate words. Before classifying text, it is necessary to perform a word segmentation operation to convert a continuous language into a list of separate words and then convert it into a vector of a certain dimension. Generally, multi-label learning algorithms can be divided into two categories, problem transformation methods and adapted algorithms. This work will use customer's comments about some hotels as a training data set, which contains labels for all aspects of the hotel evaluation, aiming to analyze and compare the performance of various multi-label learning algorithms on Chinese text classification. The experiment involves three basic methods of problem transformation methods: Support Vector Machine, Random Forest, k-Nearest-Neighbor; and one adapted algorithm of Convolutional Neural Network. The experimental results show that the Support Vector Machine has better performance
Research on the Association of Mobile Social Network Users Privacy Information Based on Big Data Analysis
No full textThe issue of privacy protection for mobile social networks is a frontier topic in the field of social network applications. The existing researches on user privacy protection in mobile social network mainly focus on privacy preserving data publishing and access control. There is little research on the association of user privacy information, so it is not easy to design personalized privacy protection strategy, but also increase the complexity of user privacy settings. Therefore, this paper concentrates on the association of user privacy information taking big data analysis tools, so as to provide data support for personalized privacy protection strategy design
Biocomposite Films of Polylactic Acid Reinforced with Microcrystalline Cellulose from Pineapple Leaf Fibers
No full textPoly(lactic acid) (PLA) composite films reinforced with microcrystalline cellulose (MCC) extracted from pineapple leaf fibers (PALF) were prepared by a solution casting procedure. In an attempt to improve the interaction between PLA and cellulose, two approaches were adopted; first, poly(ethylene glycol) (PEG) was used as a surfactant, and second, the cellulosic fibers were pre-treated using tert-butanol (TBA). Lignocellulosic and cellulosic substrates were characterized using Fourier transform infrared (FTIR), wide-angle X-ray scattering (WAXS), and thermogravimetrical analysis (TGA). MCC from PALF showed good thermal stability, left few residues after decomposing, and exhibited high crystallinity index. Mechanical, thermal and thermomechanical properties of the PLA composites were also evaluated. Multiple PLA endotherms were observed in composites with TBA-treated MCC due to crystal nucleation effects. The ultimate tensile strain values for all composites were lower than that of the pristine PLA. However, 4 wt. % MCC content provided balanced engineering properties in terms of static and dynamic tensile properties