Traffic anomaly detection algorithm for CAN bus using similarity analysis Chao Wang,Xueqiao Xu∗,Ke Xiao,Yunhua He,Guangcan Yang School of Information Science and Technology,Traffic anomaly detection algorithm for CAN bus using similarity analysis

Recently,vehicles have experienced a rise in networking and informatization,leading to increased security concerns.As the most widely used automotive bus network,the Controller Area Network(CAN)bus is vulnerable to attacks,as security was not considered in its original design.This paper proposes SIDuBzip2,a traffic anomaly detection method for the CAN bus based on the bzip2 compression algorithm.The proposed method utilizes the pseudo-periodic characteristics of CAN bus traffic,constructing time series of CAN IDs and calculating the similarity between adjacent time series to identify abnormal traffic.The method consists of three parts:the conversion of CAN ID values to characters,the calculation of similarity based on bzip2 compression,and the optimal solution of model parameters.The experimental results demonstrate that the proposed SIDuBzip2 method effectively detects various attacks,including Denial of Service,replay,basic injection,mixed injection,and suppression attacks.In addition,existing CAN bus traffic anomaly detection methods are compared with the proposed method in terms of performance and delay,demonstrating the feasibility of the proposed method.

Frictional behavior during cold ring compression process of aluminum alloy 5052

The friction is the considerable boundary condition in bulk metal forming.In this paper,the ring compression test was used to evaluate the friction coefficient and factor in Coulomb friction model and Tresca friction model for the plastic deformation of aluminum alloy AA5052.The micro-macro analysis method combining surface morphology and micro-texture was used to explore the friction behaviors in AA5052 cold forming process.In general,the magnitude(μor m)of friction changes before and after a deformation threshold during ring compression.The maximum change rate of the magnitude(μor m)before and after the deformation threshold is close to 18.5%under the present experimental conditions,and the change rate decreases with increasing loading speed.The lubrication using MoS_(2) is better than that using oil at lower speeds(0.15 mm/s,1.5 mm/s),but the lubrications for MoS_(2) and oil are similar at higher speeds(15 mm/s).The surface roughness,three-dimensional topography,and surface texture of compressed ring have a sudden change around the deformation threshold,which deviate from the previous evolution trend.The increased friction after deformation threshold also promotes the formation of sufficient shear strain layer in the subsurface plane of the compressed ring,and then it hinders the formation of the typical deformation textures withβ-oriented line and promotes the appearance of shear textures such as{001}(110),{111}(uvw)and{hkl}{110)textures.