This paper describes a recursive estimation procedure for multivariate binary
densities (probability distributions of vectors of Bernoulli random variables)
using orthogonal expansions. For $d$ covariates, there are $2^d$ basis
coefficients to estimate, which renders conventional approaches computationally
prohibitive when $d$ is large.
This paper describes a method for detecting anomalies from sequentially
observed and potentially noisy data. The proposed approach consists of two main
elements: (1) filtering, or assigning a belief or likelihood to each successive
measurement based upon our ability to predict it from previous noisy
observations, and (2) hedging, or flagging potential anomalies by comparing the
current belief against a time-varying and data-adaptive threshold. The
threshold is adjusted based on the available feedback from an end user.