Abstract

The goal of the paper is to develop a specific application of the convex optimization based hypothesis testing techniques developed in A. Juditsky, A. Nemirovski, Hypothesis testing via affine detectors, Electronic Journal of Statistics 10:2204--2242, 2016. Namely, we consider the Change Detection problem as follows: given an evolving in time noisy observations of outputs of a discrete-time linear dynamical system, we intend to decide, in a sequential fashion, on the null hypothesis stating that the input to the system is a nuisance, vs. the alternative stating that the input is a signal, with both the nuisances and the nontrivial signals modeled as inputs belonging to finite unions of some given convex sets. Assuming the observation noises zero mean sub-Gaussian, we develop computation-friendly sequential decision rules and demonstrate that in our context these rules are provably near-optimal.

Highlights

  • Quick detection of change-points from data streams is a classic and fundamental problem in signal processing and statistics, with a wide range of applications from cybersecurity [21] to gene mapping [36]

  • Following the line of research in [8, 16, 17], we allow for rather general structural assumptions on the components of our setup (system (1.1) and descriptions of nuisance and signal inputs) and are looking for computation-friendly inference routine meaning that our easy-to-implement routines and their performance characteristics are given by efficient computation

  • We consider two different types of detection procedures, those based on affine and on quadratic detectors, each type dealing with its own structure of nuisance and signal inputs

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Summary

Introduction

Quick detection of change-points from data streams is a classic and fundamental problem in signal processing and statistics, with a wide range of applications from cybersecurity [21] to gene mapping [36]. Outstanding contributions include Shewhart’s control chart [33], Page’s CUSUM procedure [29], Shiryaev-Roberts procedure [34], Gordon’s non-parametric procedure [11], and window-limited procedures [19]. High-dimensional change-point detection ( referred to as the multi-sensor change-point detection) is a more recent topic, and various statistical procedures are proposed including [14, 13, 15, 18, 26, 39, 22, 6, 5, 42, 23]. There has been very little research on the computational aspect of change-point detection, especially in the high-dimensional setting

Outline
Terminology and notation
Dynamic change detection: preliminaries
Change detection via affine detectors
Implementation: preliminaries
Implementation: construction
Characterizing performance
Let ErfInv stand for the inverse error function
Near-optimality
Discussion
Numerical illustration
Extension: union-type nuisance
Gaussian case
Sub-Gaussian case
Preliminaries
Construction and performance characterization
Situation
Assumptions on observation noise
Assumptions on spots
Processing the situation: formulation
Processing the situation: computation
Real-data example
20. We need the following
Full Text
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