Search Results for author: Paul Irofti

Found 17 papers, 9 papers with code

Fusing Dictionary Learning and Support Vector Machines for Unsupervised Anomaly Detection

2 code implementations5 Apr 2024 Paul Irofti, Iulian-Andrei Hîji, Andrei Pătraşcu, Nicolae Cleju

We introduce a new anomaly detection model that unifies the OC-SVM and DL residual functions into a single composite objective, subsequently solved through K-SVD-type iterative algorithms.

Dictionary Learning Unsupervised Anomaly Detection

Learning Explicitly Conditioned Sparsifying Transforms

1 code implementation5 Mar 2024 Andrei Pătraşcu, Cristian Rusu, Paul Irofti

Sparsifying transforms became in the last decades widely known tools for finding structured sparse representations of signals in certain transform domains.

Nodal Hydraulic Head Estimation through Unscented Kalman Filter for Data-driven Leak Localization in Water Networks

1 code implementation27 Nov 2023 Luis Romero-Ben, Paul Irofti, Florin Stoican, Vicenç Puig

In this paper, we present a nodal hydraulic head estimation methodology for water distribution networks (WDN) based on an Unscented Kalman Filter (UKF) scheme with application to leak localization.

Dictionary Learning with Uniform Sparse Representations for Anomaly Detection

1 code implementation11 Jan 2022 Paul Irofti, Cristian Rusu, Andrei Pătraşcu

In this paper we use a particular DL formulation that seeks uniform sparse representations model to detect the underlying subspace of the majority of samples in a dataset, using a K-SVD-type algorithm.

Anomaly Detection Dictionary Learning

Data-driven Leak Localization in Water Distribution Networks via Dictionary Learning and Graph-based Interpolation

no code implementations12 Oct 2021 Paul Irofti, Luis Romero-Ben, Florin Stoican, Vicenç Puig

In this paper, we propose a data-driven leak localization method for water distribution networks (WDNs) which combines two complementary approaches: graph-based interpolation and dictionary classification.

Dictionary Learning

Complexity of Inexact Proximal Point Algorithm for minimizing convex functions with Holderian Growth

1 code implementation10 Aug 2021 Andrei Patrascu, Paul Irofti

Several decades ago the Proximal Point Algorithm (PPA) started to gain a long-lasting attraction for both abstract operator theory and numerical optimization communities.

Efficient and Parallel Separable Dictionary Learning

1 code implementation7 Jul 2020 Cristian Rusu, Paul Irofti

Separable, or Kronecker product, dictionaries provide natural decompositions for 2D signals, such as images.

Dictionary Learning Image Denoising

Fault Handling in Large Water Networks with Online Dictionary Learning

1 code implementation18 Mar 2020 Paul Irofti, Florin Stoican, Vicenç Puig

Fault detection and isolation in water distribution networks is an active topic due to its model's mathematical complexity and increased data availability through sensor placement.

Dictionary Learning Fault Detection

Unsupervised Dictionary Learning for Anomaly Detection

no code implementations29 Feb 2020 Paul Irofti, Andra Băltoiu

We investigate the possibilities of employing dictionary learning to address the requirements of most anomaly detection applications, such as absence of supervision, online formulations, low false positive rates.

Anomaly Detection Dictionary Learning

Stochastic proximal splitting algorithm for composite minimization

1 code implementation4 Dec 2019 Andrei Patrascu, Paul Irofti

In the large-scale or noisy contexts, when only stochastic information on the smooth part of the objective function is available, the extension of proximal gradient schemes to stochastic oracles is based on proximal tractability of the nonsmooth component and it has been deeply analyzed in the literature.

Community-Level Anomaly Detection for Anti-Money Laundering

no code implementations24 Oct 2019 Andra Baltoiu, Andrei Patrascu, Paul Irofti

Anomaly detection in networks often boils down to identifying an underlying graph structure on which the abnormal occurrence rests on.

Anomaly Detection Dictionary Learning +1

Quick survey of graph-based fraud detection methods

no code implementations24 Oct 2019 Paul Irofti, Andrei Patrascu, Andra Baltoiu

In general, anomaly detection is the problem of distinguishing between normal data samples with well defined patterns or signatures and those that do not conform to the expected profiles.

Anomaly Detection Fraud Detection

Overcomplete Dictionary Learning with Jacobi Atom Updates

no code implementations16 Sep 2015 Paul Irofti, Bogdan Dumitrescu

Dictionary learning for sparse representations is traditionally approached with sequential atom updates, in which an optimized atom is used immediately for the optimization of the next atoms.

Dictionary Learning

Efficient GPU Implementation for Single Block Orthogonal Dictionary Learning

no code implementations16 Dec 2014 Paul Irofti

Dictionary training for sparse representations involves dealing with large chunks of data and complex algorithms that determine time consuming implementations.

Dictionary Learning

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