no code implementations • 2 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.
no code implementations • 8 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.
no code implementations • 27 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.
no code implementations • 6 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.
no code implementations • 28 May 2021 • Lawrence Tray, Ioannis Kontoyiannis
Labelled networks are an important class of data, naturally appearing in numerous applications in science and engineering.
1 code implementation • 14 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.
2 code implementations • 29 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
no code implementations • 15 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.
no code implementations • 28 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.
1 code implementation • 7 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