Grzegorz J. Nalepa

Prof. Grzegorz J. Nalepa

Institute of Applied Computer Science, Jagiellonian Univeristy, 31-007 Krakow, Poland
orcid

Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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31 December 2021 in Sensors
Verified
Journal Article
Open access
PDF file
JJJakub Jakubowski
Jakub Jakubowski
PSPrzemysław Stanisz
Przemysław Stanisz
SBSzymon Bobek
Szymon Bobek
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
Development of predictive maintenance (PdM) solutions is one of the key aspects of Industry 4.0. In recent years, more attention has been paid to data-driven techniques, which use machine learning to monitor the health of an industrial asset. The major issue in the implementation of PdM models is a lack of good quality labelled data. In the paper we present how unsupervised learning using a variational autoencoder may be used to monitor the wear of rolls in a hot strip mill, a part of a steel-making site. As an additional benchmark we use a simulated turbofan engine data set provided by NASA. We also use explainability methods in order to understand the model’s predictions. The results show that the variational autoencoder slightly outperforms the base autoencoder architecture in anomaly detection tasks. However, its performance on the real use-case does not make it a production-ready solution for industry and should be a matter of further research. Furthermore, the information obtained from the explainability model can increase the reliability of the proposed artificial intelligence-based solution.

22 September 2022 in IEEE Access
Verified
Journal Article
Open access
SBSzymon Bobek
Szymon Bobek
MKMichał Kuk
Michał Kuk
MSMaciej Szelazek
Maciej Szelazek
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
Explainable Artificial Intelligence (XAI) aims to introduce transparency and intelligibility into the decision-making process of AI systems. Most often, its application concentrates on supervised machine learning problems such as classification and regression. Nevertheless, in the case of unsupervised algorithms like clustering, XAI can also bring satisfactory results. In most cases, such application is based on the transformation of an unsupervised clustering task into a supervised one and providing generalised global explanations or local explanations based on cluster centroids. However, in many cases, the global explanations are too coarse, while the centroid-based local explanations lose information about cluster shape and distribution. In this paper, we present a novel approach called ClAMP (Cluster Analysis with Multidimensional Prototypes) that aids experts in cluster analysis with human-readable rule-based explanations. The developed state-of-the-art explanation mechanism is based on cluster prototypes represented by multidimensional bounding boxes. This allows representing of arbitrary shaped clusters and combines the strengths of local explanations with the generality of global ones. We demonstrate and evaluate the use of our approach in a real-life industrial case study from the domain of steel manufacturing as well as on the benchmark datasets. The explanations generated with ClAMP were more precise than either centroid-based or global ones.

31 May 2019 in Sensors
Verified
Journal Article
Open access
PDF file
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
Krzysztof KuttKrzysztof Kutt
Krzysztof Kutt
BGBarbara Giżycka
Barbara Giżycka
PJPaweł Jemioło
Paweł Jemioło
SBSzymon Bobek
Szymon Bobek
In this paper, we consider the use of wearable sensors for providing affect-based adaptation in Ambient Intelligence (AmI) systems. We begin with discussion of selected issues regarding the applications of affective computing techniques. We describe our experiments for affect change detection with a range of wearable devices, such as wristbands and the BITalino platform, and discuss an original software solution, which we developed for this purpose. Furthermore, as a test-bed application for our work, we selected computer games. We discuss the state-of-the-art in affect-based adaptation in games, described in terms of the so-called affective loop. We present our original proposal of a conceptual design framework for games, called the affective game design patterns. As a proof-of-concept realization of this approach, we discuss some original game prototypes, which we have developed, involving emotion-based control and adaptation. Finally, we comment on a software framework, that we have previously developed, for context-aware systems which uses human emotional contexts. This framework provides means for implementing adaptive systems using mobile devices with wearable sensors.

6 October 2021
Verified
Conference Paper
Closed access
JJJakub Jakubowski
Jakub Jakubowski
PSPrzemyslaw Stanisz
Przemyslaw Stanisz
SBSzymon Bobek
Szymon Bobek
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
Anomaly detection is emerging trend in manufacturing processes and may be considered as part of the Industry 4.0 revolution. It can serve both as diagnostic tool in predictive maintenance task, as well as trace back mechanism for assessing quality of production or services. In this paper we describe and approach for explainable anomaly detection in industrial data which contains sequential and static features. We based our solution on modified autoencoder architecture with Long Short-Term Memory layers. To address a problem of explinability in deep learning and find origin of the anomalies we have engaged the SHAP method, which gives both local and global explanations of the model. Analysis of SHAP explanations allowed us to determine the source of majority of anomalies detected by deep learning model. We demonstrated the feasibility of our approach on synthetic, reproducible dataset and on real-life data gathered from hot rolling industrial process.

21 November 2024 in Engineering Applications of Artificial Intelligence
Verified
Journal Article
Closed access
LRLala RAJAOARISOA
Lala RAJAOARISOA
RRRaubertin Randrianandraina
Raubertin Randrianandraina
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
João GamaJoão Gama
João Gama

23 August 2018 in Expert Systems
Verified
Journal Article
Closed access
PDF file
SBSzymon Bobek
Szymon Bobek
Grzegorz J. NalepaGrzegorz J. Nalepa
Grzegorz J. Nalepa
MŚMateusz Ślażyński
Mateusz Ślażyński