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Effects of the Convex Topography on Railway Environmental Vibrations
Get PDFThe railway environmental vibration caused by high-speed railways is harmful to the human health, the structural safety of adjacent buildings, and the normal use of precision instruments. At the same time, it occurs frequently. In this case, the railway environmental vibration has drawn much attention with the rapid development of high-speed railways. Studies in Earthquake Engineering show that a convex topography has a great impact on ground vibrations, however, there is no consideration about the convex topographic effect in the study of the railway environmental vibration when the convex topography is near the roadway. In this paper, the influence of a convex topography on the railway environmental vibration was investigated. Two-dimensional (2D) finite element models consist of subgrade-convex topography and subgrade-flat topography are established using the finite element method. The length and the height of the analysis model are taken as 200 m and 41.3 m, respectively. The external soil of the calculation model is simulated via the artificial boundary. By comparison with measured results, the 2D finite element models were verified to be effective. The convex topographic effect is studied by conducting parameter investigations, such as the bottom width, cross-sectional shape, height-width ratio and the foundation soil properties. Results show that the dimension and cross-section shape of the convex topography and the foundation soil properties have significant effect on the convex topographic effect
Preface: Nano/Micro Structures in Application of Computational Mechanics
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On Harmonic and Ev-Degree Molecular Topological Properties of DOX, RTOX and DSL Networks
Get PDFTopological indices enable to gather information for the underlying topology of chemical structures and networks. Novel harmonic indices have been defined recently. All degree based topological indices are defined by using the classical degree concept. Recently two novel degree concept have been defined in graph theory: ve-degree and ev-degree. Ve-degree Zagreb indices have been defined by using ve-degree concept. The prediction power of the ve-degree Zagreb indices is stronger than the classical Zagreb indices. Dominating oxide, silicate and oxygen networks are important network models in view of chemistry, physics and information science. Physical and mathematical properties of dominating oxide, silicate and oxygen networks have been considerably studied in graph theory and network theory. Topological properties of the dominating oxide, silicate and oxygen networks have been intensively investigated for the last few years period. In this study we examined, the first, the fifth harmonic and ev-degree topological indices of dominating oxide (DOX), regular triangulene oxide network (RTOX) and dominating silicate network (DSL)
SWRR: The Link Scheduling Algorithm Based on Weighted Round-Robin
Get PDFWith the rapid development of the Internet, people pay more and more attention to the protection of privacy. The second-generation onion routing system Tor is the most commonly used among anonymous communication systems, which can be used to protect user privacy effectively. In recent years, Tor’s congestion problem has become the focus of attention, and it can affect Tor’s performance even user experience. Firstly, we investigate the causes of Tor network congestion and summarize some link scheduling algorithms proposed in recent years. Then we propose the link scheduling algorithm SWRR based on WRR (Weighted Round Robin). In this process, we design multiple weight functions and compare the performance of these weight functions under different congestion conditions, and the appropriate weight function is selected to be used in our algorithms based on the experiment results. Finally, we also compare the performance of SWRR with other link scheduling algorithms under different congestion conditions by experiments, and verify the effectiveness of the algorithm SWRR
Shape, Color and Texture Based CBIR System Using Fuzzy Logic Classifier
Get PDFThe perfect image retrieval and retrieval time are the two major challenges in CBIR systems. To improve the retrieval accuracy, the whole database is searched based on many image characteristics such as color, shape, texture and edge information which leads to more time consumption. This paper presents a new fuzzy based CBIR method, which utilizes colour, shape and texture attributes of the image. Fuzzy rule based system is developed by combining color, shape, and texture feature for enhanced image recovery. In this approach, DWT is used to pull out the texture characteristics and the region based moment invariant is utilized to pull out the shape features of an image. Color similarity and texture attributes are extorted using customized Color Difference Histogram (CDH). The performance evaluation based on precision and BEP measures reveals the superiority of the proposed method over renowned obtainable approaches
Online Burst Events Detection Oriented Real-Time Microblog Message Stream
Get PDFThe rapid spread of microblog messages and sensitivity of unexpected events make microblog become the public opinion center of burst events. Online burst events detection oriented real-time microblog message stream has become an important research problem in the field of microblog public opinion. Because of the large amount of real-time microblog message stream and irregular language of microblog message, it is important to process real-time microblog message stream and detect burst events accurately. In this paper, an online burst events detection framework is proposed. In this framework, abnormal messages are detected based on sliding time window and two-level hash table. Combined with event features, an online incremental clustering algorithm is used to cluster abnormal messages and detect burst events. Experimental results in the real-time microblog message stream environment show that our framework can be used in online burst events detection and has higher accuracy compared with other approaches
Efficient Analysis of Vertical Projection Histogram to Segment Arabic Handwritten Characters
Get PDFThe paper discusses the segmentation of words into characters, which is an essential task in the development process of character recognition systems, as poorly segmented characters will automatically be unrecognized. The segmentation of offline handwritten Arabic text poses a greater challenge because of its cursive nature and different writing styles. In this article, we propose a new approach to segment handwritten Arabic characters using an efficient analysis of the vertical projection histogram. Our approach was tested using a set of handwritten Arabic words from the IFN/ENIT database, and promising results were obtained
Heterogeneous Memristive Models Design and Its Application in Information Security
Get PDFBased on the three-dimensional classic Chua circuit, a nonlinear circuit containing two flux-control memristors is designed. Due to the difference in the design of the characteristic equation of the two magnetron memristors, their position form a symmetrical structure with respect to the capacitor. The existence of chaotic properties is proved by analyzing the stability of the system, including Lyapunov exponent, equilibrium point, eigenvalue, Poincare map, power spectrum, bifurcation diagram et al. Theoretical analysis and numerical calculation show that this heterogeneous memristive model is a hyperchaotic five-dimensional nonlinear dynamical system and has a strong chaotic behavior. Then, the memristive system is applied to digital image and speech signal processing. The analysis of the key space, sensitivity of key parameters, and statistical character of encrypted scheme imply that this model can applied widely in multimedia information security
Mechanical Behaviors and Deformation Properties of Retaining Wall Formed by Grouting Mould-Bag Pile
Get PDFThe simplified mechanical model and finite element model are established on the basis of the measured results and analysis of the grouting pile deformation monitoring, surface horizontal displacement and vertical displacement monitoring, deep horizontal displacement (inclinometer) monitoring, soil pressure monitoring and seepage pressure monitoring in the lower reaches of Wuan River regulation project in Shishi, Fujian Province. The mechanical behavior and deformation performance of mould-bag pile retaining wall formed after controlled cement grouting in the silty stratum of the test section are analyzed and compared. The results show that the use of controlled cement grouting mould-bag pile technology is to strengthen the soft stratum for sealing water and reinforcement, so that it can rock into a retaining wall, which can both retain soil and seal water with excellent effect. The control of cement grouting technology not only makes the soft soil rock in the range of retaining wall of mould-bag pile, but also makes a wide range of soil around the mould-bag pile squeeze and embed to compaction; and its cohesion and internal friction angle increased, so as to achieve the purpose of reducing soil pressure and improving mechanical and deformation properties of retaining wall
Bending and Rolling Shear Properties of Cross-Laminated Timber Fabricated with Canadian Hemlock
Get PDFIn this paper, bending performance and rolling shear properties of cross-laminated timber (CLT) panels made from Canadian hemlock were investigated by varied approaches. Firstly, three groups of bending tests of three-layer CLT panels with different spans were carried out. Different failure modes were obtained: bending failure, rolling shear failure, bonding line failure, local failure of the outer layer and mixed failure mode. Deflection and strain measurements were employed to calculate the global and local modulus of elastic (MOE), compared with the theoretical value. In addition, a modified compression shear testing method was introduced to evaluate the rolling shear strength and modulus, compared with the results from strain measurements in bending shear tests. According to testing results, bonding line failure and rolling shear failure were dominant failure modes in bending tests, and the theoretical value of bending property was beyond the average level of the calculating results obtained from both deflection and strain measurements. In addition, the rolling shear strength and modulus obtained from compression shear tests were relatively smaller than those from bending tests