Multi-target pig tracking algorithm based on joint probability data association and particle filter

In order to evaluate the health status of pigs in time, monitor accurately the disease dynamics of live pigs, and reduce the morbidity and mortality of pigs in the existing large-scale farming model, pig detection and tracking technology based on machine vision are used to monitor the behavior of pigs. However, it is challenging to efficiently detect and track pigs with noise caused by occlusion and interaction between targets. In view of the actual breeding conditions of pigs and the limitations of existing behavior monitoring technology of an individual pig, this study proposed a method that used color feature, target centroid and the minimum circumscribed rectangle length-width ratio as the features to build a multi-target tracking algorithm, which based on joint probability data association and particle filter. Experimental results show the proposed algorithm can quickly and accurately track pigs in the video, and it is able to cope with partial occlusions and recover the tracks after temporary loss

BIOMECHANICAL STUDY OF PUSH-OFF TECHNIQUE FOR HANDSPRING AND FRONT SALTO VAULT

The push-off technique has a decisive effect on the choice of vault and its successful execution during gymnastic competition. This paper presents a new technique, namely the push-off with downward extension of the shoulder. By biomechanical analysis, the two kinds of push-off techniques, which are used in the front salto and handspring maneuver were compared. High-speed photography, automatic film analysis and test comparison were used to examine the difference between two push-off techniques. Results showed that the push-off technique with the downward extension of the shoulder is logical, effective and advanced

Multilayer relaxations on high-miller-index metal surfaces

Ph.DDOCTOR OF PHILOSOPH

The role of collective motion in the ultrafast charge transfer in van der Waals heterostructures.

The success of van der Waals heterostructures made of graphene, metal dichalcogenides and other layered materials, hinges on the understanding of charge transfer across the interface as the foundation for new device concepts and applications. In contrast to conventional heterostructures, where a strong interfacial coupling is essential to charge transfer, recent experimental findings indicate that van der Waals heterostructues can exhibit ultrafast charge transfer despite the weak binding of these heterostructures. Here we find, using time-dependent density functional theory molecular dynamics, that the collective motion of excitons at the interface leads to plasma oscillations associated with optical excitation. By constructing a simple model of the van der Waals heterostructure, we show that there exists an unexpected criticality of the oscillations, yielding rapid charge transfer across the interface. Application to the MoS2/WS2 heterostructure yields good agreement with experiments, indicating near complete charge transfer within a timescale of 100 fs