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This paper investigates the requirements of spoofing attack on multiple drones which are navigated by GPS signals and can communicate with each other. Moreover, the performance of spoofing attack with different numbers of counterfeit signals is studied. This work also studies and simulates the spoofing attack on drones navigated by OTDOA positioning which is defined by 3GPP and can be provided by cellular networks

Bilinear model has been shown to be very effective in a variety of fine-grained classification tasks. For the deficiencies of high-dimensional feature, a low-dimensional bilinear model is proposed. The model saves computing time greatly as well as decreases a large number of parameters by principal component analysis (PCA), and we use singular value decomposition (SVD) to replace covariance calculation. To enhance the generality of the model in the wild, we collected millions of images from bird community and flicker websites, then a new density-distance clustering method is used to eliminate a large number of noise images. Finally, a large-scale fine-grained bird dataset is constructed, which consists of 516981 images with 1329 bird categories in China. The low-dimensional bilinear model is validated on standard small-scale CUB bird dataset and our new bird dataset. The experimental results show that the proposed low-dimensional bilinear model performs better than other competing models in term of bird recognition accuracy.

The mechanisms of tracking and erosion failure of high temperature vulcanized HTV silicone rubber were studied by means of the inclined-plane test. Test conditions were varied by using different kinds of electrolytic contamination solutions instead of the stipulated NH/sub 4/Cl. Arc current I, arc burning, and extinguishing time t/sub a/ and t/sub 0/ were all recorded. Therefore, both the energy E/sub a/ dissipated on the sample surface in each t/sub a/ and the average energy E/sub t/ dissipated on the sample surface per minute could be calculated. Boiling temperatures T/sub b/ of different saturated contamination solutions were also measured. The tracking and erosion test results of silicone rubber showed a good correspondence with E/sub a/ and T/sub b/, but a poor correspondence with E/sub t/. The higher the E/sub a/ and T/sub b/, the severer the tracking and erosion damage of test samples. This means that the tracking and erosion failure of silicone rubber in the inclined-plane test is mainly caused by the heat absorbed on a simple surface in each arc burning time, and the actions of successively burned arcs are independent. >