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  • Constructive Texture Steganography Based on Compression Mapping of Secret Messages
  • Abstract This paper proposes a new constructive texture synthesis steganographic scheme by compressing original secret messages. First, we divide the original message into multiple bit blocks, which are transferred to decimal values and compressed into small decimal values by recording their interval sign characters. Then, a candidate pattern is generated by combining the given source pattern and boundary extension algorithm. Furthermore, we segment the candidate pattern into multiple candidate patches and use affine transformation algorithm to locate secret positions on a blank canvas, which are used to hide the sign characters by mapping the candidate patches. Finally, we select the candidate…
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  •   Views:364       Downloads:204        Download PDF
  • Three-Dimensional Collapse Analysis for a Shallow Cavity in Layered Strata Based on Upper Bound Theorem
  • Abstract Layered rock strata are observed to be common during the excavation of tunnels or cavities, and may significantly affect the deformation and failure characteristics of surrounding rock masses due to various complex forms and mechanical properties. In this paper, we propose a three-dimensional axisymmetric velocity field for roof collapse of shallow cavities in multi rock layers, by considering the influences of roof cross-section shapes, supporting pressure, ground overload, etc. The internal energy dissipation rate and work rates of external forces corresponding to the velocity field are computed by employing the Hoek-Brown strength criterion and its associated flow rule. Further, the…
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  •   Views:625       Downloads:243        Download PDF
  • Solute Removal Analysis of a Large-scale Fracture Plane Considering Different Flow Paths and Different Hydraulic Head Differences
  • Abstract An experimental and numerical study was carried out to investigate the solute removal process through a large-scale fracture plane considering different flow paths and hydraulic head differences. The visualization techniques were utilized in the experiment to capture the removal process images, which were then transferred to binary images. The variations in dimensionless concentration, which is defined as saturation of solute phase, were analyzed. With increasing hydraulic head difference, the speed of solute removal increases and the dimensionless concentration decreases. The flow paths result in different solute distribution patterns and different mechanisms for solute removal such as advection and diffusion, thus…
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  •   Views:648       Downloads:310        Download PDF
  • Stability Control of Gob-Side Entry Retaining in Fully Mechanized Caving Face Based on a Compatible Deformation Model
  • Abstract The stability control of gob-side entry retaining in fully mechanized caving face is a typical challenge in many coal mines in China. The rotation and subsidence of the lateral cantilever play a critical role in a coal mine, possibly leading to instability in a coal seam wall or a gob-side wall due to its excessive rotation subsidence. Hence, the presplitting blasting measures in the roof was implemented to cut down the lower main roof and convert it to caved immediate roof strata, which can significantly reduce the rotation space for the lateral cantilever and effectively control its rotation. Firstly, the…
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  •   Views:640       Downloads:254        Download PDF
  • A Re-Parametrization-Based Bayesian Differential Analysis Algorithm for Gene Regulatory Networks Modeled with Structural Equation Models
  • Abstract Under different conditions, gene regulatory networks (GRNs) of the same gene set could be similar but different. The differential analysis of GRNs under different conditions is important for understanding condition-specific gene regulatory relationships. In a naive approach, existing GRN inference algorithms can be used to separately estimate two GRNs under different conditions and identify the differences between them. However, in this way, the similarities between the pairwise GRNs are not taken into account. Several joint differential analysis algorithms have been proposed recently, which were proved to outperform the naive approach apparently. In this paper, we model the GRNs under different…
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  •   Views:349       Downloads:154        Download PDF
  • Analysis of the Quasi-Static Buffeting Responses of Transmission Lines to Moving Downburst
  • Abstract Downburst event is identified as a major cause to failure of transmission lines in non-coastal regions. In this paper, a novel nonlinear analytical frame for quasi-static buffeting responses of hinged and multi-span insulator-line systems are derived based on the theory of cable structure. The closed-form solutions are presented and applied to predict nonlinear response including displacements and other reactions of the system subjected to a moving downburst wind in a case study. Accuracy and efficiency of the derived analytical frame are validated via comparisons with results from finite element method.
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  •   Views:264       Downloads:152        Download PDF
  • A Statistical Model for Phase Difference Spectrum of Ground-Motion and Its Application in Generating Non-Stationary Seismic Waves
  • Abstract The intensity non-stationarity is one of the most important features of earthquake records. Modeling of this feature is significant to the generation of arti- ficial earthquake waves. Based on the theory of phase difference spectrum, an intensity non-stationary envelope function with log-normal form is proposed. Through a tremendous amount of earthquake records downloaded on Kik-net, a parameter fitting procedure using the genetic algorithm is conducted to obtain the value of model parameters under different magnitudes, epicenter distances and site conditions. A numerical example is presented to describe the procedure of generating fully non-stationary ground motions via spectral representation, and the…
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  •   Views:317       Downloads:139        Download PDF
  • Investigation into Spatter Particles and Their Effect on the Formation Quality During Selective Laser Melting Processes
  • Abstract During the selective laser melting process, a high-energy laser beam acts on the powder, a molten pool is rapidly generated and the characteristic parameters are constantly changing. Among them, temperature is one of the important parameters in the forming process. Due to the generation of splash particles, there will be defects in the microstructure, which will seriously affect the formation quality of the prepared parts. Therefore, it is necessary to study the relationships between the splash behavior, molten pool characteristics and product quality. The finite element simulation of the transient temperature field was performed by ANSYS software. Time-series images at…
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  •   Views:351       Downloads:251        Download PDF
  • Numerical Simulation of Multi-Layer Penetration Process of Binder Droplet in 3DP Technique
  • Abstract This paper studies the binder droplet injection process in the 3DP technique. The mathematical model of the binder penetration process for multi-nozzle and multi-layer in 3DP technique is established, by using the conservation Level set method. According to the two-dimensional plane model of three-dimensional spatial structure of sand bed, the construction method of an equivalent cylindrical mapping infiltration model is proposed to represent the porosity of the model in the two-dimensional plane, which is exactly the same as that in the three-dimensional space, as well as closer to the arrangement of the three-dimensional space, and to realize the differentiation between…
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  •   Views:371       Downloads:157        Download PDF
  • Parametric Structural Optimization of 2D Complex Shape Based on Isogeometric Analysis
  • Abstract The geometric model and the analysis model can be unified together through the isogeometric analysis method, which has potential to achieve seamless integration of CAD and CAE. Parametric design is a mainstream and successful method in CAD field. This method is not continued in simulation and optimization stage because of the model conversion in conventional optimization method based on the finite element analysis. So integration of the parametric modeling and the structural optimization by using isogeometric analysis is a natural and interesting issue. This paper proposed a method to realize a structural optimization of parametric complex shapes by using isogeometric…
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  •   Views:225       Downloads:137        Download PDF
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