Modeling and Estimation for Self-Exciting Spatio-Temporal Models of Terrorist Activity

Spatio-temporal hierarchical modeling is an extremely attractive way to model the spread of crime or terrorism data over a given region, especially when the observations are counts and must be modeled discretely. The spatio-temporal diffusion is placed, as a matter of convenience, in the process model allowing for straightforward estimation of the diffusion parameters through Bayesian techniques. However, this method of modeling does not allow for the existence of self-excitation, or a temporal data model dependency, that has been shown to exist in criminal and terrorism data. In this manuscript we will use existing theories on how violence spreads to create models that allow for both spatio-temporal diffusion in the process model as well as temporal diffusion, or self-excitation, in the data model. We will further demonstrate how Laplace approximations similar to their use in Integrated Nested Laplace Approximation can be used to quickly and accurately conduct inference of self-exciting spatio-temporal models allowing practitioners a new way of fitting and comparing multiple process models. We will illustrate this approach by fitting a self-exciting spatio-temporal model to terrorism data in Iraq and demonstrate how choice of process model leads to differing conclusions on the existence of self-excitation in the data and differing conclusions on how violence is spreading spatio-temporally

An Extended Laplace Approximation Method for Bayesian Inference of Self-Exciting Spatial-Temporal Models of Count Data

Self-Exciting models are statistical models of count data where the probability of an event occurring is influenced by the history of the process. In particular, self-exciting spatio-temporal models allow for spatial dependence as well as temporal self-excitation. For large spatial or temporal regions, however, the model leads to an intractable likelihood. An increasingly common method for dealing with large spatio-temporal models is by using Laplace approximations (LA). This method is convenient as it can easily be applied and is quickly implemented. However, as we will demonstrate in this manuscript, when applied to self-exciting Poisson spatial-temporal models, Laplace Approximations result in a significant bias in estimating some parameters. Due to this bias, we propose using up to sixth-order corrections to the LA for fitting these models. We will demonstrate how to do this in a Bayesian setting for Self-Exciting Spatio-Temporal models. We will further show there is a limited parameter space where the extended LA method still has bias. In these uncommon instances we will demonstrate how a more computationally intensive fully Bayesian approach using the Stan software program is possible in those rare instances. The performance of the extended LA method is illustrated with both simulation and real-world data

The Church of England and the Legislative Reforms of 1828-32: Revolution or Adjustment?

Since the 1950s, historians of the eighteenth- and nineteenth-century Church of England have generally maintained that the Sacramental Test Act (1828), the Roman Catholic Relief Act (1829) and the Reform Act (1832) amounted to a ‘constitutional revolution’, in which Anglican political hegemony was decisively displaced. This theory remains the dominant framework for understanding the effect of legislation on the relationship between church and state in pre-Victorian England. This article probes the validity of the theory. It is argued that the legislative reforms of 1828–32 did not drastically alter the religious composition of parliament, which was already multi-denominational, and that they incorporated clauses which preserved the political dominance of the Church of England. Additionally, it is suggested that Anglican apprehensions concerning the reforming measures of those years were derived from an unfounded belief that these reforms would ultimately result in changes to the Church of England’s formularies or in disestablishment, rather than from the actual laws enacted. Accordingly, the post-1832 British parliamentary system did not in the short term militate against Anglican interests. In light of this reappraisal, these legislative reforms may be better understood as an exercise in ‘constitutional adjustment’ as opposed to a ‘constitutional revolution’.Pembroke College, Cambridg

The Morality of Intimate Faculty-Student Relationships

Presented September 19, 1996 for the Center for the Study of Ethics in Societ

Truth was his defense: The libel trial of John Peter Zenger

John Peter Zenger spent nearly eight months in jail starting in 1734 but still printed The New York Weekly Journal with the help of his wife while he was on trial for seditious libel. In those days, libel was anything that was against the government. It didn’t matter if the information was true or false. Controversy plagued Zenger’s trial from the beginning as William Cosby, the governor of New York, did everything he could to sabotage Zenger as Cosby was the centerpiece of most of Zenger’s editorials. Zenger was one of the first journalists to emphasize the importance of the media being the fourth estate and being a watchdog of the government

Queen Adelaide and the Extension of Anglicanism in Malta

On a visit to Malta in 1838, Queen Adelaide expressed severe disappointment that the British colony did not possess a purpose-built Anglican place of worship. She determined to fund the building of one at her personal expense and within six years the grandiose neoclassical church of St Paul's, Valletta, was completed. This imposing structure occupied an ambiguous position in a colony where the British government was pledged to maintain Roman Catholicism. St Paul's was ostensibly intended for the existing Anglican population in Malta. However, the church was perceived by both evangelicals and Roman Catholics as a potential instrument of propagating Protestantism. In examining the basis for these perceptions, this article suggests that St Paul's was part of a larger effort, driven by high church clergy connected with the Society for Promoting Christian Knowledge (SPCK), to influence the Maltese towards greater sympathy with the Anglican tradition, while avoiding overt proselytizing. The concomitant establishment of the diocese of Gibraltar in 1842 was, it is argued, key to this enterprise. The analysis advanced here has important implications for our understanding of Anglicanism in an imperial context, the contribution of royal patronage to this process and the conflict between religious and governmental imperatives.</jats:p

Time-Varying Input and State Delay Compensation for Uncertain Nonlinear Systems

A robust controller is developed for uncertain, second-order nonlinear systems subject to simultaneous unknown, time-varying state delays and known, time-varying input delays in addition to additive, sufficiently smooth disturbances. An integral term composed of previous control values facilitates a delay-free open-loop error system and the development of the feedback control structure. A stability analysis based on Lyapunov-Krasovskii (LK) functionals guarantees uniformly ultimately bounded tracking under the assumption that the delays are bounded and slowly varying