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CAN( controller area network) bus is the most widely used field bus. Due to the lack of authentication and message checking mechanism, CAN bus has great security risks, so it is necessary to design a defense mechanism for CAN bus. In this paper, a priority hopping mechanism is designed, which introduces the dynamic hopping of identifiers by Hash function into a real-time scheduling algorithm. The fixed priority is calculated by a genetic algorithm, and the compromise range of priority is found out. Each frame is grouped, and the ID segment of data frame is segmented and reconstructed. The former part of the ID segment determines the priority and performs priority hopping, while the latter part of the ID segment hops dynamically at one time. Experimental results show that using dynamic priority and one-time ID Hopping to hop has a greater security improvement than the existing ID Hopping mechanism. [ABSTRACT FROM AUTHOR]

Sunshine has played a critical role in trajectory analysis. It is of great significance to design an algorithm that could not only estimate the sunshine information of the trajectory effectively, but also remove the redundant points and keep the necessary sunshine-based information. This paper proposes a sunshine based trajectory simplification algorithm, which considers the urban trajectory character, to solve the challenges of trajectory analyzing in various sunshine related scenarios. On the one hand, an orientation model is established to abstract the relationship between trajectory and sunlight. On the other hand, a sunshine related trajectory simplification model is proposed, and the genetic algorithm is applied to find the points that need to be reserved. Finally, the real-world data of Minneapolis, US, is used for experiment. The results demonstrate that the proposed algorithm can effectively reduce the number of turning points in the trajectories under the control of bound Tmax. [ABSTRACT FROM AUTHOR]

The paper proposed a research model based on the CSM model， which was deduced by Colorado School of Mines， to minimize the unbalanced radial force and overturning moment. The model followed the principle of cutterhead minimum specific energy and utilized the normal genetic algorithm to optimize the spacing of the center cutters， the normal cutters and the gage cutters， and in turn， to improve the polar angle of the normal cutters and the gage cutters. Taking the TB880E cutterhead as an object， the research revealed that when the cutter spacing of center cutters and the normal cutters have been improved， the specific energy can be reduced by about 1.53%. Similarly， when the tilt angles of the gage cutters have been optimized， the specific energy can be reduced by about 1.10%. When the polar angles of the normal cutters and the gage cutters have been improved， the unbalanced radial force can be reduced to 0.1265 N， and the overturning moment can be reduced to 0.7591 N/m， which may decrease the deformation of the cutterhead. The present research can be applied in the optimization design of the locations of the disc cutters on the cutterhead and in the prediction of the energy consumption of rock fragmentation process， which can reduce the energy of the rock fragmentation and improve the boring efficiency. [ABSTRACT FROM AUTHOR]

In view of helical drill point grinding， the theoretical and experimental bases for grinding the required geometrical parameters of helical drill points are presented in this paper based on the optimization of biglide parallel machine grinding parameters. A method of grinding the involute helical surface based on the biglide parallel machine is introduced， and then the mathematical model is derived for the helical drill flank. Moreover， the relationship between the geometric parameters and grinding parameters is analyzed， and the optimal grinding parameters are acquired based on genetic algorithm. The results showed that the optimized grinding parameters improve the grinding precision with the experiment on the biglide parallel machine， and the biglide parallel machine can satisfy clients' demands of drill grinding. [ABSTRACT FROM AUTHOR]