Rafal Drezewski

Prof. Rafal Drezewski

AGH University of Science and Technology, Kraków, Małopolskie, Poland
orcid

Research Focus & Metrics

Academic Career Length

24Years (2003-Present)

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

Representative Publications

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1 February 2015 in Information Sciences
Verified
Journal Article
Closed access
Rafal DrezewskiRafal Drezewski
Rafal Drezewski
JSJan Sepielak
Jan Sepielak
WFWojciech Filipkowski
Wojciech Filipkowski

1 January 2015 in The Knowledge Engineering Review
Verified
Journal Article
Closed access
PDF file
ABAleksander Byrski
Aleksander Byrski
Rafal DrezewskiRafal Drezewski
Rafal Drezewski
Leszek SiwikLeszek Siwik
Leszek Siwik
MKMarek Kisiel-Dorohinicki
Marek Kisiel-Dorohinicki
The aim of this paper is to give a survey on the development and applications of evolutionary multi-agent systems (EMAS). The paper starts with a general introduction describing the background, structure and behaviour of EMAS. EMAS application to solving global optimisation problems is presented in the next section along with its modification targeted at lowering the computation costs by early removing certain agents based on immunological inspirations. Subsequent sections deal with the elitist variant of EMAS aimed at solving multi-criteria optimisation problems, and the co-evolutionary one aimed at solving multi-modal optimisation problems. Each variation of EMAS is illustrated with selected experimental results.

3 March 2025 in IEEE Access
Verified
Journal Article
Open access
Shoffan SaifullahShoffan Saifullah
Shoffan Saifullah
Rafal DrezewskiRafal Drezewski
Rafal Drezewski
AYAnton Yudhana
Anton Yudhana
ASAndiko Putro Suryotomo
Andiko Putro Suryotomo
Automated brain tumor segmentation from MRI images is critical for accurate diagnosis and treatment planning. This study presents a novel ResUNet50-based approach, integrating ResNet50 as an encoder within the U-Net framework to achieve robust and precise segmentation. The proposed model was evaluated on two datasets: a Kaggle-based T1-CE MRI dataset and BraTS 2018, ensuring comprehensive assessment across different imaging conditions. ResUNet50 outperformed state-of-the-art models, achieving Dice coefficients exceeding 0.95 and Jaccard indices above 0.91 on the Kaggle dataset. Additionally, experiments on BraTS 2018 Whole Tumor segmentation across multiple MRI modalities (FLAIR, T1, T1-CE, and T2) demonstrated high accuracy on both High-Grade Gliomas (HGG) and Low-Grade Gliomas (LGG), confirming model generalization. Statistical significance tests (Paired t-tests and Wilcoxon Signed-Rank Tests, p < 0.05) validated the improvements over existing approaches. Furthermore, ResUNet50 reduced parameters by over 60% and accelerated inference time by 4.8× compared to U-Net, enhancing its potential for clinical deployment. Future work will focus on ensemble learning and bio-inspired optimization for improved robustness across multi-center MRI datasets. Explainable AI techniques such as Grad-CAM and saliency maps will be incorporated to enhance interpretability, improving clinical applicability.

8 December 2023 in Procedia Computer Science
Verified
Journal Article
Open access
SSShoffan Saifullah
Shoffan Saifullah
Rafal DrezewskiRafal Drezewski
Rafal Drezewski

19 December 2022 in ILKOM Jurnal Ilmiah
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Journal Article
Open access
PDF file
HJHerlina Jayadianti
Herlina Jayadianti
WKWilis Kaswidjanti
Wilis Kaswidjanti
AUAgung Tri Utomo
Agung Tri Utomo
Shoffan SaifullahShoffan Saifullah
Shoffan Saifullah
FDFelix Andika Dwiyanto
Felix Andika Dwiyanto
Rafal DrezewskiRafal Drezewski
Rafal Drezewski
Reviews are a form of user experience information on a product or service that can be used as a reference for potential consumers’ preferences to buy, use, or consume a product. They can be also used by business entities to find out public opinion about their product or the performance of their business products. It will be very difficult to process the review data manually and it will take a long time. Therefore, sentiment analysis automation can be used to get polarity information from existing reviews. In this study, IndoBERT with Recurrent Convolutional Neural Network (RCNN) was used to automate sentiment analysis of Indonesian reviews. The data used was a sentiment analysis dataset obtained from IndoNLU with sentiment consisting of negative sentiment, neutral sentiment, and positive sentiment. The results of the test showed that IndoBERT with the Recurrent Convolutional Neural Network (RCNN) had better results than the IndoBERT base. IndoBERT with Recurrent Convolutional Neural Network (RCNN) obtained 95.16% accuracy, 94.05% precision, 92.74% recall and 93.27% f1 score.

22 January 2024 in Applied Sciences
Verified
Journal Article
Open access
PDF file
Shoffan SaifullahShoffan Saifullah
Shoffan Saifullah
Rafal DrezewskiRafal Drezewski
Rafal Drezewski
Accurate medical image segmentation is paramount for precise diagnosis and treatment in modern healthcare. This research presents a comprehensive study of the efficacy of particle swarm optimization (PSO) combined with histogram equalization (HE) preprocessing for medical image segmentation, focusing on lung CT scan and chest X-ray datasets. Best-cost values reveal the PSO algorithm’s performance, with HE preprocessing demonstrating significant stabilization and enhanced convergence, particularly for complex lung CT scan images. Evaluation metrics, including accuracy, precision, recall, F1-score/Dice, specificity, and Jaccard, show substantial improvements with HE preprocessing, emphasizing its impact on segmentation accuracy. Comparative analyses against alternative methods, such as Otsu, Watershed, and K-means, confirm the competitiveness of the PSO-HE approach, especially for chest X-ray images. The study also underscores the positive influence of preprocessing on image clarity and precision. These findings highlight the promise of the PSO-HE approach for advancing the accuracy and reliability of medical image segmentation and pave the way for further research and method integration to enhance this critical healthcare application.