Title
The Hawkes process with renewal immigration & its estimation with an EM algorithm
Abstract
In its original form, the self-excited Hawkes process is a cluster process where immigrants follow a Poisson process, and each immigrant may form a cluster of multi-generational offspring. The Hawkes process is generalized by replacing the Poisson immigration process with a renewal process. This generalization makes direct MLE impossible. Thus, two EM algorithms are introduced: The first extends the existing EM algorithm for the Hawkes process to consider renewal immigration. It treats the entire branching structure-which points are immigrants, and which point is the parent of each offspring-as missing data. The second algorithm reduces the amount of missing data, considering only if a point is an immigrant or not as missing data. This significantly reduces computational complexity and memory requirements, enabling estimation on larger datasets. Both algorithms are found to perform well in simulation studies. A case study shows that the Hawkes process with renewal immigration is superior to the standard Hawkes process for the modeling of high-frequency price fluctuations. Further, it is demonstrated that misspecification of the immigration process can bias estimation of the branching ratio, which quantifies the degree of self-excitation.
Year
DOI
Venue
2016
10.1016/j.csda.2015.08.007
Computational Statistics & Data Analysis
Keywords
Field
DocType
Hawkes process,Renewal process,EM algorithm,Cluster process,Branching process
Econometrics,Renewal theory,Computer science,Expectation–maximization algorithm,Immigration,Poisson distribution,Missing data,Statistics,Branching process,Computational complexity theory,Branching (version control)
Journal
Volume
Issue
ISSN
94
C
0167-9473
Citations 
PageRank 
References 
3
0.70
5
Authors
3
Name
Order
Citations
PageRank
Spencer Wheatley131.04
vladimir filimonov241.41
Didier Sornette323837.50