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In the k-coverage process of target nodes, substantial data redundancy occurs, which leads to the phenomenon of congestion, reducing the network communication capability and coverage as well as accelerating network energy consumption. Therefore, this article proposes an Optimization Coverage Conserving Protocol with Authentication. This protocol provides a solution to obtain the largest coverage probability for multi-nodes. In the optimization and authenticated calculation, the protocol provides the calculation method and verification process of the expected value of multi-node coverage; when the moving target nodes are continuously covered, this protocol provides a process to solve for the focused target nodes; when there is redundancy coverage, this article provides a process to calculate the coverage probability when any sensor node is covered by a redundant node. Furthermore, through comparisons of the coverage quality and network lifetime with other algorithms, the performance indexes of this protocol have been substantially increased by the simulation experiment, which verified the effectiveness and viability of the protocol in this article. [ABSTRACT FROM AUTHOR]

The Pillars of Creation, one of the most recognized objects in the sky, are believed to be associated with the formation of young stars. However, so far, the formation and maintenance mechanism of the pillars are still not fully understood due to the complexity of the nonlinear radiation magnetohydrodynamics (RMHD). Here, assuming laboratory laser-driven conditions, we studied the self-consistent dynamics of pillar structures in magnetic fields by means of two-dimensional and three-dimensional (3D) RMHD simulations, and the results support our proposed experimental scheme. We find that only when the magnetic pressure and ablation pressure are comparable, the magnetic field can significantly alter the plasma hydrodynamics. For medium-magnetized cases (β initial ≈ 3.5), the initial magnetic fields undergo compression and amplification. This amplification results in the magnetic pressure inside the pillar becoming large enough to support the sides of the pillar against radial collapse due to pressure from the surrounding hot plasma. This effect is particularly pronounced for the parallel component (B y ), which is consistent with observational results. In contrast, a strong perpendicular (B x , B z ) magnetic field (β initial < 1) almost retains its initial distribution and significantly suppresses the expansion of blown-off gas plasma, leading to the inability to form pillar-like structures. The 3D simulations suggest that the bending at the head of "Column I" in the Pillars of Creation may be due to nonparallel magnetic fields. After similarity scaling transformation, our results can be applied to explain the formation and maintenance mechanism of the pillars, and can also provide useful information for future experimental designs. [ABSTRACT FROM AUTHOR]

This article presents a model to simulate the dynamics of mirror cutting process. Mirror cutting is used for machining thin-walled workpiece, consisting of an external turning tool and internal boring bar. The thin-wall workpiece and long slender boring bar are easily subjected to vibrations. It is difficult to ensure the processing quality of the thin-walled workpiece for conventional machining methods, such as turning, boring, and milling. Mirror cutting is a simultaneous machining method for internal boring and external turning and has the same normal uncut chips. In this way, the radial cutting force of the workpiece can be counteracted, thereby reducing radial vibration and enhancing the stability of the system. The mirror cutting is a multi-input–multi-output (MIMO) cutting system consisting of external turning and internal boring. The proposed method simulates the mirror cutting by state space model. By using the state space model, it is possible to simulate the MIMO machining dynamic system. The dynamic simulation of the mirror cutting system in the cutting process is realized and verified by comparison with the measured signal. [ABSTRACT FROM AUTHOR]

Optimisation design of composite structures required an accurate predictive model for forming behaviour. The simulation process contains a number of model parameters which include transverse and longitudinal viscosities of continuous fibre-reinforced viscous composites, fundamental to predicting the shear rheology. These two shearing viscosities are defined by the viscosity tensor where transverse and longitudinal viscosities are respectively the shearing resistance for the unidirectional composite across and along the fibre direction. This paper reviews previous work on modelling techniques, which would offer some insight in development of a fully predictive physical model so as to eliminate any time-consuming experimental characterisation. It is suggested that neglect of non-Newtonian effects, viscoelastic effects (fibre elastic deformation), and fibre rearrangement during shearing could be the main reason for the existing models underestimating test data. Recommendations for future work are made. [ABSTRACT FROM AUTHOR]