Regarding to the problems of low detection accuracy， poor real-time performance， and missed detection of small target vehicles in existing road vehicle detection and recognition algorithms， a road vehicle detection and recognition algorithm based on densely connected convolutional neural networks was proposed. Firstly， Based on YOLOv4 （You Only Look Once version 4） network framework， by adopting the densely connected deep residual network structure， the feature reuse in the feature extraction stage was strengthened to realize the use of features with lower complexity on shallow layers. Then， a jump connection structure was integrated to the multi-scale feature fusion network to strengthen the feature information fusion and expression capability of the network， which reduced the missed detection rate of vehicles. Finally， the dimensional clustering algorithm was used to recalculate the anchor sizes， which were allocated to different detection scales according to a reasonable strategy. Experimental results show that the proposed algorithm achieves the detection accuracy of 98.21% and the detection speed of 48.05 frame/s on KITTI dataset， and it also has a good detection effect for vehicles in the complex and harsh environment of Berkeley DeepDrive （BDD100K） dataset， ensuring required real-time performance and effective accuracy improvement.

With the growth of cloud technology, distributed application platform develops towards elasticity resources and dynamic migration environment. The refinement of distributed application access control policies was associated with resources and environment, which also needs to improve performance to adapt to the dynamics. Although present access control space policies conflict analysis methods could be used in the conflict analysis of distributed application access control policies refinement. The granularity of its calculating unit is too fine to make batter performance. In this article, the authors designed a conflict analysis algorithm used in distributed application access control policies refinement, the conflict analysis algorithm was based on recursive calculation the intersection of sets and the calculation unit of the algorithm was permission assignment unit which improved computing granularity. The experimental results and analysis show that the proposed algorithm has better performance, and fits the needs of improving computing performance of cloud platform access control policies refinement.

Chip layer assignment is a key step in analytical placement of 3D Integrated Circuits (ICs). Analytical placement could face the conversion from 3D continuous space in z-direction to several connected 2D chip layer spaces by layer assignment. However, layer assignment may destroy the previous optimal solution in 3D continuous space. To realize the transition from an optimal 3D placement to a legalized, layer-assigned placement smoothly, a layer assignment method was proposed by using the minimum cost flow, which protected solution space and inherited optimal wirelength at most. The layer assignment method was embedded in a multilevel non-linear placement of 3D ICs which minimized the weighted sum of total wirelength and Through Silicon Via (TSV) number subject to area density constraints. The proposed placement algorithm can achieve better wirelength results, TSV number and run time in comparison with the recent 3D placement methods.

It has been proved in many researches that there are some design flaws in IEEE 802.1X standard. In order to eliminate the Denial of Service (DoS) attack, replay attack, session hijack, Man-In-the-Middle (MIM) attack and other security threats, the protocol was analyzed in view of the state machines. It is pointed out that the origin of these problems is the inequality and incompleteness of state machines as well as the lack of integrity protection and source authenticity on messages. However, an improvement proposal called Dual-way Challenge Handshake and Logoff Authentication was proposed, and a formal analysis was done on it with an improved BAN logic. It is proved that the proposal can effectively resist the security threats mentioned above.