Search Results for author: Christos Diou

Found 27 papers, 9 papers with code

Effector: A Python package for regional explanations

1 code implementation3 Apr 2024 Vasilis Gkolemis, Christos Diou, Eirini Ntoutsi, Theodore Dalamagas, Bernd Bischl, Julia Herbinger, Giuseppe Casalicchio

Effector implements well-established global effect methods, assesses the heterogeneity of each method and, based on that, provides regional effects.

C-XGBoost: A tree boosting model for causal effect estimation

no code implementations31 Mar 2024 Niki Kiriakidou, Ioannis E. Livieris, Christos Diou

Causal effect estimation aims at estimating the Average Treatment Effect as well as the Conditional Average Treatment Effect of a treatment to an outcome from the available data.

Causal Inference

RHALE: Robust and Heterogeneity-aware Accumulated Local Effects

1 code implementation20 Sep 2023 Vasilis Gkolemis, Theodore Dalamagas, Eirini Ntoutsi, Christos Diou

RHALE quantifies the heterogeneity by considering the standard deviation of the local effects and automatically determines an optimal variable-size bin-splitting.

Multiscale and Multilayer Contrastive Learning for Domain Generalization

1 code implementation28 Aug 2023 Aristotelis Ballas, Christos Diou

During the past decade, deep neural networks have led to fast-paced progress and significant achievements in computer vision problems, for both academia and industry.

Contrastive Learning Domain Generalization +2

Detection of Anomalies in Multivariate Time Series Using Ensemble Techniques

no code implementations6 Aug 2023 Anastasios Iliopoulos, John Violos, Christos Diou, Iraklis Varlamis

To boost the performance of these base models, we propose a feature-bagging technique that considers only a subset of features at a time, and we further apply a transformation that is based on nested rotation computed from Principal Component Analysis (PCA) to improve the effectiveness and generalization of the approach.

Anomaly Detection Time Series

Towards Fair Face Verification: An In-depth Analysis of Demographic Biases

no code implementations19 Jul 2023 Ioannis Sarridis, Christos Koutlis, Symeon Papadopoulos, Christos Diou

This paper presents an in-depth analysis, with a particular emphasis on the intersectionality of these demographic factors.

Face Recognition Face Verification +2

CNN Feature Map Augmentation for Single-Source Domain Generalization

no code implementations26 May 2023 Aristotelis Ballas, Christos Diou

In search of robust and generalizable machine learning models, Domain Generalization (DG) has gained significant traction during the past few years.

Domain Generalization Image Classification

Integrating Nearest Neighbors with Neural Network Models for Treatment Effect Estimation

no code implementations11 May 2023 Niki Kiriakidou, Christos Diou

The proposed NNCI methodology is applied to some of the most well established neural network-based models for treatment effect estimation with the use of observational data.

Causal Inference

FLAC: Fairness-Aware Representation Learning by Suppressing Attribute-Class Associations

1 code implementation27 Apr 2023 Ioannis Sarridis, Christos Koutlis, Symeon Papadopoulos, Christos Diou

To overcome these limitations, this work introduces FLAC, a methodology that minimizes mutual information between the features extracted by the model and a protected attribute, without the use of attribute labels.

Age/Bias-conflicting Age/Unbiased +13

CNNs with Multi-Level Attention for Domain Generalization

no code implementations2 Apr 2023 Aristotelis Ballas, Christos Diou

In the present work, we focus on this problem of Domain Generalization and propose an alternative neural network architecture for robust, out-of-distribution image classification.

Classification Domain Generalization +2

Towards Domain Generalization for ECG and EEG Classification: Algorithms and Benchmarks

1 code implementation20 Mar 2023 Aristotelis Ballas, Christos Diou

Our objective in this work is to propose a benchmark for evaluating DG algorithms, in addition to introducing a novel architecture for tackling DG in biosignal classification.

Domain Generalization EEG +1

Partially Oblivious Neural Network Inference

no code implementations27 Oct 2022 Panagiotis Rizomiliotis, Christos Diou, Aikaterini Triakosia, Ilias Kyrannas, Konstantinos Tserpes

Oblivious inference is the task of outsourcing a ML model, like neural-networks, without disclosing critical and sensitive information, like the model's parameters.

DALE: Differential Accumulated Local Effects for efficient and accurate global explanations

1 code implementation10 Oct 2022 Vasilis Gkolemis, Theodore Dalamagas, Christos Diou

In this paper, we propose a novel ALE approximation, called Differential Accumulated Local Effects (DALE), which can be used in cases where the ML model is differentiable and an auto-differentiable framework is accessible.

An evaluation framework for comparing causal inference models

no code implementations31 Aug 2022 Niki Kiriakidou, Christos Diou

In this paper, we propose to complement the evaluation of causal inference models using concrete statistical evidence, including the performance profiles of Dolan and Mor{\'e}, as well as non-parametric and post-hoc statistical tests.

Benchmarking Causal Inference

Listen2YourHeart: A Self-Supervised Approach for Detecting Murmur in Heart-Beat Sounds

no code implementations31 Aug 2022 Aristotelis Ballas, Vasileios Papapanagiotou, Anastasios Delopoulos, Christos Diou

The PhysioNet 2022 challenge targets automatic detection of murmur from audio recordings of the heart and automatic detection of normal vs. abnormal clinical outcome.

Self-Supervised Learning

Intake Monitoring in Free-Living Conditions: Overview and Lessons we Have Learned

no code implementations4 Jun 2022 Christos Diou, Konstantinos Kyritsis, Vasileios Papapanagiotou, Ioannis Sarafis

The progress in artificial intelligence and machine learning algorithms over the past decade has enabled the development of new methods for the objective measurement of eating, including both the measurement of eating episodes as well as the measurement of in-meal eating behavior.

An improved neural network model for treatment effect estimation

no code implementations23 May 2022 Niki Kiriakidou, Christos Diou

Nowadays, in many scientific and industrial fields there is an increasing need for estimating treatment effects and answering causal questions.

Self-Supervised Feature Learning of 1D Convolutional Neural Networks with Contrastive Loss for Eating Detection Using an In-Ear Microphone

1 code implementation2 Aug 2021 Vasileios Papapanagiotou, Christos Diou, Anastasios Delopoulos

A common bottleneck for developing and training machine learning algorithms is obtaining labeled data for training supervised algorithms, and in particular ground truth annotations.

Image Classification

Recognition of food-texture attributes using an in-ear microphone

no code implementations20 May 2021 Vasileios Papapanagiotou, Christos Diou, Janet van den Boer, Monica Mars, Anastasios Delopoulos

Our approach performs very well in recognizing crispiness (0. 95 weighted accuracy on new subjects and 0. 93 on new food types) and demonstrates promising results for objective and automatic recognition of wetness and chewiness.

Attribute

A Data Driven End-to-end Approach for In-the-wild Monitoring of Eating Behavior Using Smartwatches

no code implementations12 Oct 2020 Konstantinos Kyritsis, Christos Diou, Anastasios Delopoulos

The increased worldwide prevalence of obesity has sparked the interest of the scientific community towards tools that objectively and automatically monitor eating behavior.

Temporal Localization

Span error bound for weighted SVM with applications in hyperparameter selection

no code implementations17 Sep 2018 Ioannis Sarafis, Christos Diou, Anastasios Delopoulos

Experiments on 14 benchmark data sets and data sets with importance scores for the training instances show that: (a) the condition for the existence of span in weighted SVM is satisfied almost always; (b) the span-rule is the most effective method for weighted SVM hyperparameter selection; (c) the span-rule is the best predictor of the test error in the mean square error sense; and (d) the span-rule is efficient and, for certain problems, it can be calculated faster than $K$-fold cross-validation.

Learning Local Feature Aggregation Functions with Backpropagation

no code implementations26 Jun 2017 Angelos Katharopoulos, Despoina Paschalidou, Christos Diou, Anastasios Delopoulos

This paper introduces a family of local feature aggregation functions and a novel method to estimate their parameters, such that they generate optimal representations for classification (or any task that can be expressed as a cost function minimization problem).

General Classification

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