Search Results for author: Kleanthis Malialis

Found 15 papers, 6 papers with code

Incremental Learning with Concept Drift Detection and Prototype-based Embeddings for Graph Stream Classification

no code implementations3 Apr 2024 Kleanthis Malialis, Jin Li, Christos G. Panayiotou, Marios M. Polycarpou

Data stream mining aims at extracting meaningful knowledge from continually evolving data streams, addressing the challenges posed by nonstationary environments, particularly, concept drift which refers to a change in the underlying data distribution over time.

Decision Making Incremental Learning

Pandemic infection forecasting through compartmental model and learning-based approaches

no code implementations12 Jan 2024 Marianna Karapitta, Andreas Kasis, Charithea Stylianides, Kleanthis Malialis, Panayiotis Kolios

Motivated by this, we present a hybrid pandemic infection forecasting methodology that integrates compartmental model and learning-based approaches.

A Study of Data-driven Methods for Adaptive Forecasting of COVID-19 Cases

no code implementations18 Sep 2023 Charithea Stylianides, Kleanthis Malialis, Panayiotis Kolios

Severe acute respiratory disease SARS-CoV-2 has had a found impact on public health systems and healthcare emergency response especially with respect to making decisions on the most effective measures to be taken at any given time.

Decision Making Incremental Learning

Unsupervised Unlearning of Concept Drift with Autoencoders

1 code implementation23 Nov 2022 André Artelt, Kleanthis Malialis, Christos Panayiotou, Marios Polycarpou, Barbara Hammer

Consequently, learning models operating on the data stream might become obsolete, and need costly and difficult adjustments such as retraining or adaptation.

Incremental Learning

Data augmentation on-the-fly and active learning in data stream classification

1 code implementation13 Oct 2022 Kleanthis Malialis, Dimitris Papatheodoulou, Stylianos Filippou, Christos G. Panayiotou, Marios M. Polycarpou

Second, learning models have access to more labelled data without the need to increase the active learning budget and / or the original memory size.

Active Learning Data Augmentation +1

A Hybrid Active-Passive Approach to Imbalanced Nonstationary Data Stream Classification

no code implementations10 Oct 2022 Kleanthis Malialis, Manuel Roveri, Cesare Alippi, Christos G. Panayiotou, Marios M. Polycarpou

In real-world applications, the process generating the data might suffer from nonstationary effects (e. g., due to seasonality, faults affecting sensors or actuators, and changes in the users' behaviour).

Incremental Learning

Nonstationary data stream classification with online active learning and siamese neural networks

1 code implementation3 Oct 2022 Kleanthis Malialis, Christos G. Panayiotou, Marios M. Polycarpou

We conduct an extensive study that compares the role of different active learning budgets and strategies, the performance with/without memory, the performance with/without ensembling, in both synthetic and real-world datasets, under different data nonstationarity characteristics and class imbalance levels.

Active Learning

Data-efficient Online Classification with Siamese Networks and Active Learning

no code implementations4 Oct 2020 Kleanthis Malialis, Christos G. Panayiotou, Marios M. Polycarpou

In this paper we investigate learning from limited labelled, nonstationary and imbalanced data in online classification.

Active Learning Classification +1

Online Learning With Adaptive Rebalancing in Nonstationary Environments

1 code implementation24 Sep 2020 Kleanthis Malialis, Christos G. Panayiotou, Marios M. Polycarpou

An enormous and ever-growing volume of data is nowadays becoming available in a sequential fashion in various real-world applications.

Resource Abstraction for Reinforcement Learning in Multiagent Congestion Problems

no code implementations13 Mar 2019 Kleanthis Malialis, Sam Devlin, Daniel Kudenko

These are learning time, scalability and decentralised coordination i. e. no communication between the learning agents.

reinforcement-learning Reinforcement Learning (RL)

Queue-based Resampling for Online Class Imbalance Learning

1 code implementation27 Sep 2018 Kleanthis Malialis, Christos G. Panayiotou, Marios M. Polycarpou

Online class imbalance learning constitutes a new problem and an emerging research topic that focusses on the challenges of online learning under class imbalance and concept drift.

Real-Time Bidding by Reinforcement Learning in Display Advertising

1 code implementation10 Jan 2017 Han Cai, Kan Ren, Wei-Nan Zhang, Kleanthis Malialis, Jun Wang, Yong Yu, Defeng Guo

In this paper, we formulate the bid decision process as a reinforcement learning problem, where the state space is represented by the auction information and the campaign's real-time parameters, while an action is the bid price to set.

reinforcement-learning Reinforcement Learning (RL)

Feature Selection as a Multiagent Coordination Problem

no code implementations16 Mar 2016 Kleanthis Malialis, Jun Wang, Gary Brooks, George Frangou

In this paper, we formulate feature selection as a multiagent coordination problem and propose a novel feature selection method using multiagent reinforcement learning.

feature selection reinforcement-learning +1

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