This paper proposes a hierarchical perception model for simulation of crowd perception in different density. In this model, there are two tiers: the low density and high density perception modules. They are both composed of perceptual filters, short-term and long-term memory. However, considering the changes of the perception as the density increases, we adopt different methods to model them. We also take into account the impact of the human subjective factors on the selection of the object the virtual agent focuses. Our hierarchical perception model can well reflect the characteristics of the human perception; moreover, it can provide more plausible information for the virtual human among the crowd to respond properly to certain event.

Abstract Oral cancer being one of the lethal cancers is generally detected at advanced stages and causes significant mortality world over. The unavailability of the reliable biomarkers and therapeutic targets/agents forms a bottleneck in the treatment of oral cancer. MicroRNAs are considered of immense therapeutic potential for the treatment of cancer. Consistently, in this study the role and therapeutic potential of miR-650 was explored in oral cancer. The analysis of miR-650 expression by qRT-PCR revealed significant ( p  < 0.05) upregulation of miR-650 in oral cancer cell lines. Cell cycle analysis by flow cytometery revealed that suppression of miR-650 significantly ( p  < 0.05) inhibits the proliferation of the SCC-25 cells by prompting Sub-G1 cell cycle arrest. Further, miR-650 suppression also inhibited the migration and invasion of the SCC-25 oral cancer cells as revealed by transwell assays. TargetScan analysis showed that miR-650 targets Growth factor independent 1 (Gfi1). Moreover, the results of western blot analysis showed that miR-650 suppression inhibits the expression of Gfi1. Interestingly, suppression of Gfi1 exhibited similar effects on cell proliferation, migration and invasion of the oral cancer cells as that of miR-650 suppression. Nonetheless, miR-650 promoted the proliferation, migration and invasion of the SCC-25 cells by upregulating the expression of Gfi1. Moreover, overexpression of miR-650 could not rescue the effects of Gfi1 silencing on SCC-25 oral cancer cells. Conversely, overexpression of Gfi1 could rescue the effects of miR-650 inhibition on SCC-25 cell proliferation, migration and invasion. Additionally, miR-650 suppression could also inhibit the xenografted tumor growth in vivo by inhibiting the expression of Gfi1. Taken together, miR-650 may prove to be an important therapeutic target for the management of oral cancers. Highlights • MiR-650 is significantly upregulated in oral cancer cells. • Inhibition of miR-650 suppresses the proliferation, migration and invasion of the oral cancer cells by targeting Gfi1. • Gfi1 overexpression rescues the inhibitory effects of miR-650 on the proliferation of the oral cancer cells. • Overexpression of miR-650 promotes the proliferation, migration and invasion of the oral cancer cells. • Inhibition of miR-650 suppresses the tumor growth in xenografted mice.