9. A computer system for determining a crowd behavior, the system comprising: a memory having computer readable instructions; and a processor configured to execute the computer readable instructions, the instructions comprising: collecting, at one or more recording points in a crowd of individuals, audible expressions that the individuals of the crowd make; generating a graph of the audible expressions as the audible expressions are collected from the individuals, wherein the graph comprises nodes that represent tokens and edges that represent temporal precedence in the audible expressions; determining a crowd behavior by performing a graphical text analysis on the graph; and outputting an indication of the crowd behavior to trigger a crowd control measure, wherein the crowd behavior comprises a risk metric, and wherein the crowd control measure is triggered when the risk metric is above a threshold.
9. A computer system for determining a crowd behavior, the system comprising: a memory having computer readable instructions; and a processor configured to execute the computer readable instructions, the instructions comprising: collecting, at one or more recording points in a crowd of individuals, audible expressions that the individuals of the crowd make; generating a graph of the audible expressions as the audible expressions are collected from the individuals, wherein the graph comprises nodes that represent tokens and edges that represent temporal precedence in the audible expressions; determining a crowd behavior by performing a graphical text analysis on the graph; and outputting an indication of the crowd behavior to trigger a crowd control measure, wherein the crowd behavior comprises a risk metric, and wherein the crowd control measure is triggered when the risk metric is above a threshold. 12. The computer system of claim 9 , wherein the method further comprises: collecting text messages that the individuals send; and using the text messages to generate the graph.