Summary Panel count data arise when the number of recurrent events experienced by each subject is observed intermittently at discrete examination times. The examination time process can be informative about the underlying recurrent event process even after conditioning on covariates. We consider a semiparametric accelerated mean model for the recurrent event process and allow the two processes to be correlated through a shared frailty. The regression parameters have a simple marginal interpretation of modifying the time scale of the cumulative mean function of the event process. A novel estimation procedure for the regression parameters and the baseline rate function is proposed based on a conditioning technique. In contrast to existing methods, the proposed method is robust in the sense that it requires neither the strong Poisson-type assumption for the underlying recurrent event process nor a parametric assumption on the distribution of the unobserved frailty. Moreover, the distribution of the examination time process is left unspecified, allowing for arbitrary dependence between the two processes. Asymptotic consistency of the estimator is established, and the variance of the estimator is estimated by a model-based smoothed bootstrap procedure. Numerical studies demonstrated that the proposed point estimator and variance estimator perform well with practical sample sizes. The methods are applied to data from a skin cancer chemoprevention trial.
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Order Book Queue Hawkes Markovian Modeling
This article presents a Hawkes process model with Markovian baseline intensi- ties for high-frequency order book data modeling. We classied intraday order book trading events into a range of categories based on their order types and the price change after their arrivals. In order to capture the stimulating eects between mul- tiple types of order book events, we use multivariate Hawkes process to model the self- and mutually-exciting event arrivals. We also integrate a Markovian baseline intensities into the event arrival dynamic, by including the impacts of order book liquidity state and time factor on the baseline intensity. A regression-based non- parametric estimation procedure is adopted to estimate the model parameters in our Hawkes+Markovian model. To eliminate redundant model parameters, LASSO reg- ularization is incorporated into the estimation procedure. Besides, model selection method based on Akaike Information Criteria is applied to evaluate the eect of each part of the proposed model. An implementation example based on real LOB data is provided. Through the example we studied the empirical shapes of Hawkes excitement functions, the eects of liquidity as well as time factors, the LASSO vari- able selection, and the explanation power of Hawkes and Markovian elements to the dynamics of order book.
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- Award ID(s):
- 2106433
- PAR ID:
- 10509851
- Publisher / Repository:
- SIAM J. Financial Mathematics
- Date Published:
- Journal Name:
- Annals of Operations Research
- Volume:
- 336
- Issue:
- 1-2
- ISSN:
- 0254-5330
- Page Range / eLocation ID:
- 481 to 503
- Subject(s) / Keyword(s):
- Hawkes Process, Order book modeling, Non-parametric estimation, Model selection
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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