29 research outputs found
Toward the application of XAI methods in EEG-based systems
An interesting case of the well-known Dataset Shift Problem is the
classification of Electroencephalogram (EEG) signals in the context of
Brain-Computer Interface (BCI). The non-stationarity of EEG signals can lead to
poor generalisation performance in BCI classification systems used in different
sessions, also from the same subject. In this paper, we start from the
hypothesis that the Dataset Shift problem can be alleviated by exploiting
suitable eXplainable Artificial Intelligence (XAI) methods to locate and
transform the relevant characteristics of the input for the goal of
classification. In particular, we focus on an experimental analysis of
explanations produced by several XAI methods on an ML system trained on a
typical EEG dataset for emotion recognition. Results show that many relevant
components found by XAI methods are shared across the sessions and can be used
to build a system able to generalise better. However, relevant components of
the input signal also appear to be highly dependent on the input itself.Comment: Accepted to be presented at XAI.it 2022 - Italian Workshop on
Explainable Artificial Intelligenc
On The Effects Of Data Normalisation For Domain Adaptation On EEG Data
In the Machine Learning (ML) literature, a well-known problem is the Dataset
Shift problem where, differently from the ML standard hypothesis, the data in
the training and test sets can follow different probability distributions,
leading ML systems toward poor generalisation performances. This problem is
intensely felt in the Brain-Computer Interface (BCI) context, where bio-signals
as Electroencephalographic (EEG) are often used. In fact, EEG signals are
highly non-stationary both over time and between different subjects. To
overcome this problem, several proposed solutions are based on recent transfer
learning approaches such as Domain Adaption (DA). In several cases, however,
the actual causes of the improvements remain ambiguous. This paper focuses on
the impact of data normalisation, or standardisation strategies applied
together with DA methods. In particular, using \textit{SEED}, \textit{DEAP},
and \textit{BCI Competition IV 2a} EEG datasets, we experimentally evaluated
the impact of different normalization strategies applied with and without
several well-known DA methods, comparing the obtained performances. It results
that the choice of the normalisation strategy plays a key role on the
classifier performances in DA scenarios, and interestingly, in several cases,
the use of only an appropriate normalisation schema outperforms the DA
technique.Comment: Published in its final version on Engineering Applications of
Artificial Intelligence (EAAI) https://doi.org/10.1016/j.engappai.2023.10620
Strategies to exploit XAI to improve classification systems
Explainable Artificial Intelligence (XAI) aims to provide insights into the
decision-making process of AI models, allowing users to understand their
results beyond their decisions. A significant goal of XAI is to improve the
performance of AI models by providing explanations for their decision-making
processes. However, most XAI literature focuses on how to explain an AI system,
while less attention has been given to how XAI methods can be exploited to
improve an AI system. In this work, a set of well-known XAI methods typically
used with Machine Learning (ML) classification tasks are investigated to verify
if they can be exploited, not just to provide explanations but also to improve
the performance of the model itself. To this aim, two strategies to use the
explanation to improve a classification system are reported and empirically
evaluated on three datasets: Fashion-MNIST, CIFAR10, and STL10. Results suggest
that explanations built by Integrated Gradients highlight input features that
can be effectively used to improve classification performance.Comment: This work has been accepted to be presented to The 1st World
Conference on eXplainable Artificial Intelligence (xAI 2023), July 26-28,
2023 - Lisboa, Portuga
Semi-supervised detection of structural damage using Variational Autoencoder and a One-Class Support Vector Machine
In recent years, Artificial Neural Networks (ANNs) have been introduced in
Structural Health Monitoring (SHM) systems. A semi-supervised method with a
data-driven approach allows the ANN training on data acquired from an undamaged
structural condition to detect structural damages. In standard approaches,
after the training stage, a decision rule is manually defined to detect
anomalous data. However, this process could be made automatic using machine
learning methods, whom performances are maximised using hyperparameter
optimization techniques. The paper proposes a semi-supervised method with a
data-driven approach to detect structural anomalies. The methodology consists
of: (i) a Variational Autoencoder (VAE) to approximate undamaged data
distribution and (ii) a One-Class Support Vector Machine (OC-SVM) to
discriminate different health conditions using damage sensitive features
extracted from VAE's signal reconstruction. The method is applied to a scale
steel structure that was tested in nine damage's scenarios by IASC-ASCE
Structural Health Monitoring Task Group
EEG-based measurement system for monitoring student engagement in learning 4.0
A wearable system for the personalized EEG-based detection of engagement in learning 4.0 is proposed. In particular, the effectiveness of the proposed solution is assessed by means of the classification accuracy in predicting engagement. The system can be used to make an automated teaching platform adaptable to the user, by managing eventual drops in the cognitive and emotional engagement. The effectiveness of the learning process mainly depends on the engagement level of the learner. In case of distraction, lack of interest or superficial participation, the teaching strategy could be personalized by an automatic modulation of contents and communication strategies. The system is validated by an experimental case study on twenty-one students. The experimental task was to learn how a specific human-machine interface works. Both the cognitive and motor skills of participants were involved. De facto standard stimuli, namely (1) cognitive task (Continuous Performance Test), (2) music background (Music Emotion Recognition-MER database), and (3) social feedback (Hermans and De Houwer database), were employed to guarantee a metrologically founded reference. In within-subject approach, the proposed signal processing pipeline (Filter bank, Common Spatial Pattern, and Support Vector Machine), reaches almost 77% average accuracy, in detecting both cognitive and emotional engagement
Nephroplex: a kidney-focused NGS panel highlights the challenges of PKD1 sequencing and identifies a founder BBS4 mutation
Background: Genetic testing of patients with inherited kidney diseases has emerged as a tool of clinical utility by improving the patients' diagnosis, prognosis, surveillance and therapy.
Methods: The present study applied a Next Generation Sequencing (NGS)-based panel, named NephroPlex, testing 115 genes causing renal diseases, to 119 individuals, including 107 probands and 12 relatives. Thirty-five (poly)cystic and 72 non (poly)cystic individuals were enrolled. The latter subgroup of patients included Bardet-Biedl syndrome (BBS) patients, as major components.
Results: Disease-causing mutations were identified in 51.5 and 40% of polycystic and non-polycystic individuals, respectively. Autosomal dominant polycystic kidney disease (ADPKD) patients with truncating PKD1 variants showed a trend towards a greater slope of the age-estimated glomerular filtration rate (eGFR) regression line than patients with (i) missense variants, (ii) any PKD2 mutations and (iii) no detected mutations, according to previous findings. The analysis of BBS individuals showed a similar frequency of BBS4,9,10 and 12 mutations. Of note, all BBS4-mutated patients harbored the novel c.332+1G>GTT variant, which was absent in public databases, however, in our internal database, an additional heterozygote carrier was found. All BBS4-mutated individuals originated from the same geographical area encompassing the coastal provinces of Naples.
Discussion: In conclusion, these findings indicate the potential for a genetic panel to provide useful information at both clinical and epidemiological levels
Area 5000 - Relazione preliminare
SI presentano i risultati della campagna di scavo condotta al Castello di Rivarola (Carasco -GE) nell'Area 5000. Ai piedi della torre esterna viene individuato un ampio fossato difensivo in fase con la torre stessa ma defunzionalizzato prima del suo abbattimento