Search Results for author: Petros Dellaportas

Found 12 papers, 8 papers with code

Towards a Framework for a New Research Ecosystem

no code implementations12 Dec 2023 Roberto Savona, Cristina Maria Alberini, Lucia Alessi, Iacopo Baussano, Petros Dellaportas, Ranieri Guerra, Sean Khozin, Andrea Modena, Sergio Pecorelli, Guido Rasi, Paolo Daniele Siviero, Roger M. Stein

A major gap exists between the conceptual suggestion of how much a nation should invest in science, innovation, and technology, and the practical implementation of what is done.

Learning variational autoencoders via MCMC speed measures

1 code implementation26 Aug 2023 Marcel Hirt, Vasileios Kreouzis, Petros Dellaportas

Variational autoencoders (VAEs) are popular likelihood-based generative models which can be efficiently trained by maximizing an Evidence Lower Bound (ELBO).

Reservoir Computing for Macroeconomic Forecasting with Mixed Frequency Data

1 code implementation1 Nov 2022 Giovanni Ballarin, Petros Dellaportas, Lyudmila Grigoryeva, Marcel Hirt, Sophie van Huellen, Juan-Pablo Ortega

Macroeconomic forecasting has recently started embracing techniques that can deal with large-scale datasets and series with unequal release periods.

How Good are Low-Rank Approximations in Gaussian Process Regression?

1 code implementation13 Dec 2021 Constantinos Daskalakis, Petros Dellaportas, Aristeidis Panos

In particular, we bound the Kullback-Leibler divergence between an exact GP and one resulting from one of the afore-described low-rank approximations to its kernel, as well as between their corresponding predictive densities, and we also bound the error between predictive mean vectors and between predictive covariance matrices computed using the exact versus using the approximate GP.

regression

Entropy-based adaptive Hamiltonian Monte Carlo

1 code implementation NeurIPS 2021 Marcel Hirt, Michalis K. Titsias, Petros Dellaportas

Hamiltonian Monte Carlo (HMC) is a popular Markov Chain Monte Carlo (MCMC) algorithm to sample from an unnormalized probability distribution.

Scalable Marked Point Processes for Exchangeable and Non-Exchangeable Event Sequences

1 code implementation30 May 2021 Aristeidis Panos, Ioannis Kosmidis, Petros Dellaportas

We adopt the interpretability offered by a parametric, Hawkes-process-inspired conditional probability mass function for the marks and apply variational inference techniques to derive a general and scalable inferential framework for marked point processes.

Point Processes Variational Inference

How Good are Low-Rank Approximations in Gaussian Process Regression?

3 code implementations3 Apr 2020 Constantinos Daskalakis, Petros Dellaportas, Aristeidis Panos

In particular, we bound the Kullback-Leibler divergence between an exact GP and one resulting from one of the afore-described low-rank approximations to its kernel, as well as between their corresponding predictive densities, and we also bound the error between predictive mean vectors and between predictive covariance matrices computed using the exact versus using the approximate GP.

Gaussian Processes regression

Gradient-based Adaptive Markov Chain Monte Carlo

1 code implementation NeurIPS 2019 Michalis K. Titsias, Petros Dellaportas

We introduce a gradient-based learning method to automatically adapt Markov chain Monte Carlo (MCMC) proposal distributions to intractable targets.

Copula-like Variational Inference

1 code implementation NeurIPS 2019 Marcel Hirt, Petros Dellaportas, Alain Durmus

This family is based on new copula-like densities on the hypercube with non-uniform marginals which can be sampled efficiently, i. e. with a complexity linear in the dimension of state space.

Variational Inference

Bayesian prediction of jumps in large panels of time series data

no code implementations28 Mar 2019 Angelos Alexopoulos, Petros Dellaportas, Omiros Papaspiliopoulos

We take a new look at the problem of disentangling the volatility and jumps processes of daily stock returns.

Time Series Time Series Analysis

Fully Scalable Gaussian Processes using Subspace Inducing Inputs

no code implementations6 Jul 2018 Aristeidis Panos, Petros Dellaportas, Michalis K. Titsias

We introduce fully scalable Gaussian processes, an implementation scheme that tackles the problem of treating a high number of training instances together with high dimensional input data.

Extreme Multi-Label Classification Gaussian Processes +1

Cannot find the paper you are looking for? You can Submit a new open access paper.