[1] Konstantinova P, Udvarev A, Semerdjiev T. A study of a target tracking algorithm using global nearest neighbor approach[C]//Proceedings of the International Conference on Computer Systems and Technologies, 2003.
[2] Ekman M, Sviestins E, Sjoberg L. Particle filters for tracking closely spaced targets[C]//IEEE International Conference on Information Fusion, 2007: 1-8.
[3] Koch W. Experimental results on Bayesian MHT for maneuvering closely-spaced objects in a densely cluttered environment[C]// Radar 97, 1997: 729-733.
[4] Cucker F, Smale S. Emergent behavior in flocks [J]. Automatic Control, IEEE Transactions on, 2007, 52(5): 852-862. doi:  10.1109/TAC.2007.895842
[5] Swain A, Clark D. The single-group PHD filter: an an alytic solution[C]//Information Fusion (FUSION), 2011 Proceedings of the 14th International Conference on. IEEE, 2011: 1-8.
[6] Gning A, Mihaylova L, Maskell S, et al. Group object structure and state estimation with evolving networks and Monte Carlo methods [J]. Signal Processing, IEEE Transactions on, 2011, 59(4): 1383-1396. doi:  10.1109/TSP.2010.2103062
[7] Aroor A, Epstein S, Korpan R. Mengeros: A crowd simulation tool for autonomous robot navigation[C]//Proc AAAI Fall Symp, 2017: 123–125.
[8] Lin T Y, Goyal P, Girshick R, et al. Focal loss for dense object detection[C]//2017 IEEE International Conference on Computer Vision (ICCV), 2020.
[9] Wang Q, Chen M, Nie F, et al. Detecting coherent groups in crowd scenes by multiview clustering [J]. IEEE Trans Pattern Anal Mach Intell, 2020, 42(1): 46-58. doi:  10.1109/TPAMI.2018.2875002
[10] Zhang Y, Qin L, Ji R, et al. Exploring coherent motion patterns via structured trajectory learning for crowd mood modeling [J]. IEEE Transactions on Circuits and Systems for Video Technology, 2017, 27(3): 635-648. doi:  10.1109/TCSVT.2016.2593609
[11] Nie F, Wang X, Jordan M, et al. The constrained laplacian rank algorithm for graph-based clustering[C]//AAAI Conference on Artificial Intelligence, 2016: 1969–1976.
[12] Zhou B, Tang X, Wang X. Coherent filtering: Detecting coherent motions from crowd clutters[C]//European Conference on Computer Vision. Springer, Berlin, Heidelberg, 2012: 857-871.
[13] Shao J, Change Loy C, Wang X. Scene-independent group profiling in crowd[C]//Proceedings of the IEEE Conference on Computer Vision and Pattern Recognition, 2014: 2219-2226.