Self-exciting point process models of civilian deaths in Iraq

Abstract

Our goal in this paper is to analyze temporal patterns of civilian death reports in Iraq. For this purpose we employ a branching point process model similar to those used in earthquake analysis. Here the rate of events is partitioned into the sum of a Poisson background rate and a self-exciting component in which events trigger an increase in the rate of the process.More specifically, each event generated by the process in turn generates a sequence of offspring events according to a Poisson distribution. Whereas the background rate is typically assumed to be stationary for seismic activity, such an assumption is not valid in the context of civilian deaths in Iraq. We propose three simple adjustments to account for background rate variation and compare the effectiveness of each model using Iraq Body Count data from 2003 to 2007.Our results indicate that branching point processes are well suited for modeling the temporal dynamics of violence in Iraq.

Reconstruction of missing data in social networks based on temporal patterns of interactions

“…This agrees with the evidence that retaliations are commonplace among rival gangs [14,15]. A similar approach was used to model repeat and near-repeat burglary effects in [16,17] and temporal dynamics of violence in Iraq in [18], where self-excitation is one of the key qualitative features of the process. We assume that the interaction events for each pair of agents occur independently according to a Hawkes process.…”

An “Estimate & Score Algorithm” for simultaneous parameter estimation and reconstruction of incomplete data on social networks

“…In this paper, the data was assumed to come from a Hawkes process with constant background rate and an exponential response to previous events. There are cases where the background rate is not constant [40]. Further it is conceivable that the response function could be of a form other than an exponential decay.…”

Point-process models of social network interactions: Parameter estimation and missing data recovery

“…The Hawkes process appears in the seismology literature as a model for the timing of earthquakes and their aftershocks [26]. As interest in and availability of large data sets of human activities have grown, Hawkes processes have been used to model electronic Point-process models of social network interactions communications [5], gang crimes [10,15,34], and even terrorist and insurgent activity [19,25].…”