no code implementations • 3 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.
no code implementations • 12 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.
no code implementations • 18 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.
no code implementations • 15 May 2023 • Jin Li, Kleanthis Malialis, Marios M. Polycarpou
In our digital universe nowadays, enormous amount of data are produced in a streaming manner in a variety of application areas.
1 code implementation • 23 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.
1 code implementation • 13 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.
no code implementations • 10 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).
1 code implementation • 3 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.
no code implementations • 30 Sep 2022 • Dimitris Papatheodoulou, Pavlos Pavlou, Stelios G. Vrachimis, Kleanthis Malialis, Demetrios G. Eliades, Theocharis Theocharides
Numerous real-world problems from a diverse set of application areas exist that exhibit temporal dependencies.
no code implementations • 4 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.
1 code implementation • 24 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.
no code implementations • 13 Mar 2019 • Kleanthis Malialis, Sam Devlin, Daniel Kudenko
These are learning time, scalability and decentralised coordination i. e. no communication between the learning agents.
1 code implementation • 27 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.
1 code implementation • 10 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.
no code implementations • 16 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.