Search Results for author: Ioannis Kontoyiannis

Found 10 papers, 3 papers with code

The Bayesian Context Trees State Space Model for time series modelling and forecasting

no code implementations2 Aug 2023 Ioannis Papageorgiou, Ioannis Kontoyiannis

The utility of the general framework is illustrated in two particular instances: When autoregressive (AR) models are used as base models, resulting in a nonlinear AR mixture model, and when conditional heteroscedastic (ARCH) models are used, resulting in a mixture model that offers a powerful and systematic way of modelling the well-known volatility asymmetries in financial data.

Bayesian Inference Time Series +1

Change-point Detection and Segmentation of Discrete Data using Bayesian Context Trees

no code implementations8 Mar 2022 Valentinian Lungu, Ioannis Papageorgiou, Ioannis Kontoyiannis

A new Bayesian modelling framework is introduced for piece-wise homogeneous variable-memory Markov chains, along with a collection of effective algorithmic tools for change-point detection and segmentation of discrete time series.

Change Point Detection Time Series +1

The ODE Method for Asymptotic Statistics in Stochastic Approximation and Reinforcement Learning

no code implementations27 Oct 2021 Vivek Borkar, Shuhang Chen, Adithya Devraj, Ioannis Kontoyiannis, Sean Meyn

In addition to standard Lipschitz assumptions and conditions on the vanishing step-size sequence, it is assumed that the associated \textit{mean flow} $ \tfrac{d}{dt} \vartheta_t = \bar{f}(\vartheta_t)$, is globally asymptotically stable with stationary point denoted $\theta^*$, where $\bar{f}(\theta)=\text{ E}[f(\theta,\Phi)]$ with $\Phi$ having the stationary distribution of the chain.

reinforcement-learning Reinforcement Learning (RL)

Context-tree weighting for real-valued time series: Bayesian inference with hierarchical mixture models

no code implementations6 Jun 2021 Ioannis Papageorgiou, Ioannis Kontoyiannis

At the bottom level, a different real-valued time series model is associated with each context-state, i. e., with each leaf of the tree.

Bayesian Inference Model Selection +2

The Feature-First Block Model

no code implementations28 May 2021 Lawrence Tray, Ioannis Kontoyiannis

Labelled networks are an important class of data, naturally appearing in numerous applications in science and engineering.

Stochastic Block Model

Population-scale testing can suppress the spread of infectious disease

1 code implementation14 Apr 2021 Jussi Taipale, Ioannis Kontoyiannis, Sten Linnarsson

Provided that results are obtained rapidly, the test frequency required to suppress an epidemic is monotonic and near-linear with respect to R0, the infectious period, and the fraction of susceptible individuals.

Bayesian Context Trees: Modelling and exact inference for discrete time series

2 code implementations29 Jul 2020 Ioannis Kontoyiannis, Lambros Mertzanis, Athina Panotopoulou, Ioannis Papageorgiou, Maria Skoularidou

We develop a new Bayesian modelling framework for the class of higher-order, variable-memory Markov chains, and introduce an associated collection of methodological tools for exact inference with discrete time series.

Methodology Information Theory Information Theory Applications Computation

Optimal rates for independence testing via $U$-statistic permutation tests

no code implementations15 Jan 2020 Thomas B. Berrett, Ioannis Kontoyiannis, Richard J. Samworth

We study the problem of independence testing given independent and identically distributed pairs taking values in a $\sigma$-finite, separable measure space.

valid

Differential Temporal Difference Learning

no code implementations28 Dec 2018 Adithya M. Devraj, Ioannis Kontoyiannis, Sean P. Meyn

Value functions derived from Markov decision processes arise as a central component of algorithms as well as performance metrics in many statistics and engineering applications of machine learning techniques.

General Reinforcement Learning

Packet Speed and Cost in Mobile Wireless Delay-Tolerant Networks

1 code implementation7 Jan 2018 Riccardo Cavallari, Stavros Toumpis, Roberto Verdone, Ioannis Kontoyiannis

A mobile wireless delay-tolerant network (DTN) model is proposed and analyzed, in which infinitely many nodes are initially placed on R^2 according to a uniform Poisson point process (PPP) and subsequently travel, independently of each other, along trajectories comprised of line segments, changing travel direction at time instances that form a Poisson process, each time selecting a new travel direction from an arbitrary distribution; all nodes maintain constant speed.

Information Theory Information Theory

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