8 research outputs found
Discovery of a missing disease spreader
This study presents a method to discover an outbreak of an infectious disease
in a region for which data are missing, but which is at work as a disease
spreader. Node discovery for the spread of an infectious disease is defined as
discriminating between the nodes which are neighboring to a missing disease
spreader node, and the rest, given a dataset on the number of cases. The spread
is described by stochastic differential equations. A perturbation theory
quantifies the impact of the missing spreader on the moments of the number of
cases. Statistical discriminators examine the mid-body or tail-ends of the
probability density function, and search for the disturbance from the missing
spreader. They are tested with computationally synthesized datasets, and
applied to the SARS outbreak and flu pandemic.Comment: in pres
Mining complex trees for hidden fruit : a graphâbased computational solution to detect latent criminal networks : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Information Technology at Massey University, Albany, New Zealand.
The detection of crime is a complex and difficult endeavour. Public and private organisations â focusing on law enforcement, intelligence, and compliance â commonly apply the rational isolated actor approach premised on observability and materiality. This is manifested largely as conducting entity-level risk management sourcing âleadsâ from reactive covert human intelligence sources and/or proactive sources by applying simple rules-based models. Focusing on discrete observable and material actors simply ignores that criminal activity exists within a complex system deriving its fundamental structural fabric from the complex interactions between actors - with those most unobservable likely to be both criminally proficient and influential. The graph-based computational solution developed to detect latent criminal networks is a response to the inadequacy of the rational isolated actor approach that ignores the connectedness and complexity of criminality.
The core computational solution, written in the R language, consists of novel entity resolution, link discovery, and knowledge discovery technology. Entity resolution enables the fusion of multiple datasets with high accuracy (mean F-measure of 0.986 versus competitors 0.872), generating a graph-based expressive view of the problem. Link discovery is comprised of link prediction and link inference, enabling the high-performance detection (accuracy of ~0.8 versus relevant published models ~0.45) of unobserved relationships such as identity fraud. Knowledge discovery uses the fused graph generated and applies the âGraphExtractâ algorithm to create a set of subgraphs representing latent functional criminal groups, and a mesoscopic graph representing how this set of criminal groups are interconnected. Latent knowledge is generated from a range of metrics including the âSuper-brokerâ metric and attitude prediction.
The computational solution has been evaluated on a range of datasets that mimic an applied setting, demonstrating a scalable (tested on ~18 million node graphs) and performant (~33 hours runtime on a non-distributed platform) solution that successfully detects relevant latent functional criminal groups in around 90% of cases sampled and enables the contextual understanding of the broader criminal system through the mesoscopic graph and associated metadata. The augmented data assets generated provide a multi-perspective systems view of criminal activity that enable advanced informed decision making across the microscopic mesoscopic macroscopic spectrum