Applied sciences

Bulletin of the Polish Academy of Sciences Technical Sciences

Content

Bulletin of the Polish Academy of Sciences Technical Sciences | 2026 | 74 | 3

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Abstract

The impact of pollution on the performance of photovoltaic (PV) panels and the risk of hot spots is an important issue in the context of optimizing renewable energy systems. Dust, leaves, and bird droppings cause uneven illumination of the panel surface, leading to a decrease in efficiency and local overheating of the cells, which can result in permanent damage. The use of Internet of Things (IoT) technology in PV panel monitoring enables continuous tracking of pollution levels and their impact on system performance. Smart sensors located in various places and on the drones provide real-time data on temperature and air pollution levels of various chemical compounds. The collected information is sent to artificial intelligence-based systems, which analyze patterns and identify potential threats, such as the formation of hot spots or a drop in module performance. Authors method, based on a proprietary structure and selection of deep LSTM network parameters, outperforms other specified machine learning methods in terms of relative prediction accuracy for dust. Proposed algorithm also predicts more accurately than other machine learning methods. Thermal cameras combined with AI algorithms can accurately detect temperature anomalies on the surface of the panels and predict future problems. This allows to optimize cleaning schedule and make maintenance decisions based on actual data rather than periodic inspections.
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Authors and Affiliations

Damian Mazur
1
ORCID: ORCID
Tomasz Kossowski
1
ORCID: ORCID
Grzegorz Drałus
1
ORCID: ORCID
Aneta Łobodzińska
2
ORCID: ORCID

  1. Faculty of Electrical and Computer Engineering, Rzeszow University of Technology, Poland
  2. Faculty of Mechanical Engineering and Aviation, Rzeszow University of Technology, Poland
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Abstract

Session-based recommender systems using graph neural networks (GNNs) have achieved strong performance by modeling item transitions within user sessions. Despite their success, these models often struggle to generalize well to infrequent or uncommon behavior patterns. Such patterns, due to their limited representation in the training data, are typically overshadowed by frequent transitions, leading to biased recommendations and reduced performance in real-world scenarios where long-tail behaviors are prevalent. To address this limitation, we introduce GraSS (graph-based skip-gram synthesizer), a novel data augmentation framework designed to improve the robustness of GNN-based session recommenders. GraSS identifies sessions containing rare item transitions and enriches them by generating synthetic session sequences. This is achieved by utilising skip-gram statistics to capture contextual item co-occurrences and applying random walks on an item graph to generate plausible but diverse session paths. The augmented sessions are then used to retrain the model, enabling better learning from sparse behaviors. Experiments on standard session-based recommendation benchmarks demonstrate that GraSS consistently improves recommendation accuracy.
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Authors and Affiliations

Viet Anh Nguen
1
Dang Son Nguen
1
ORCID: ORCID
Thi Nhan Vu
1
Thi Lan Anh Vu
1
Thi Ngoc Tu Nguyen
2

  1. Institude of Information Technology – Vietnam Academy of Science and Technology, Viet Nam
  2. Electric Power University, Viet Nam
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Abstract


In this paper, we consider a method for solving difficult combinatorial optimization problems on real quantum computers. We focus on the traveling salesman problem as a representative problem for a group of problems where the solution is represented by a permutation. Typically, existing algorithmic solutions use binary matrices to store this permutation – the QUBO (quadratic unconstrained binary optimization) model. We propose a new way of encoding permutations on quantum computers, using a significantly smaller number of qubits than binary matrix encodings. Our method allows for significant performance improvements for any problem whose input or solution is a permutation. We demonstrate an example implementation of the traveling salesman problem on the IQM quantum computers: IQM Spark 5-qubit ‘ODRA-5’ computer and IQM Radiance ‘Garnet’ 20-qubit computer.
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Authors and Affiliations

Igor Dudkiewicz
1
Wojciech Bożejko
1
ORCID: ORCID

  1. Department of Control and Quantum Computing, Wrocław University of Science and Technology, Janiszewskiego 11/17, 50-372 Wrocław, Poland
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Abstract

This paper investigates human-robot interaction (HRI) within the challenging, high-noise environments of educational fairs, advocating for an HCI-centered approach to evaluate social robots in unpredictable public spaces. Utilizing the advanced social robot Furhat, the study compares the effectiveness of speech-based interaction against gesture-based recognition to overcome the limitations of traditional voice systems in loud settings. Five interaction programs were evaluated: a Large Language Model (LLM) variant relying on voice, and two gesture-controlled games (Rock-Paper-Scissors and Blocks guessing game) tested both with and without passive robot gestures. The results, drawn from field tests, demonstrate that the gesture recognition module is a highly effective alternative to speech recognition in noisy environments. While the voice-based LLM program struggled with a 33% success rate and high idle times due to environmental noise, gesture-based interactions achieved significantly higher success rates, ranging from 77% to 96%. Furthermore, the study confirms that a gesturing social robot is significantly more effective at attracting attention. The inclusion of passive gestures reduced the robot idle time from an average of 141.7–143.7 seconds to 105.6–106.5 seconds, while increasing participant engagement by 16% to 21%. These findings underscore the importance of non-verbal communication and multimodal perception in fostering reliable and engaging HRI in dynamic, high-social environments.
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Authors and Affiliations

Tomasz Grzejszczak
1
ORCID: ORCID

  1. Silesian University of Technology, Faculty of Automatic Control, Electronics and Computer Science, Department of Automatic Control and Robotics,Akademicka 16, 44-100 Gliwice, Poland
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Abstract

Aiming to tackle the problems of low adaptability to dynamic environments and low planning efficiency of traditional automaticp arking path-planning algorithms, this paper proposes a hierarchical path-planning framework that integrates the improved rapidly-exploring random tree (RRT) algorithm and the dynamic window approach (DWA). Firstly, at the global planning level, a Gaussian-uniform mixeddistribution sampling strategy is adopted to optimize the growth direction of the random tree, and a dynamic step-size mechanism is incorporated to improve the algorithm expansion efficiency. Secondly, the artificial potential field (APF) method is introduced to optimize the RRT-generated path nodes, ensuring the geometric safety clearance for the vehicle chassis. Subsequently, at the local planning level, these optimized nodes serve as waypoints to guide the DWA. Dynamic obstacle-avoidance weight is introduced into the evaluation function of DWA, and this RRT-DWA collaborative framework effectively solves the problems of dynamic obstacle-avoidance and local stagnation. Finally, for the terminal parking maneuver, the Reeds-Shepp (RS) curve is used to smoothly adjust the vehicle pose to match the parking end-point. Finally, a joint simulation is carried out in Carsim/Simulink through the pure-pursuit control algorithm. The simulation experiments show that the maximum tracking error of the planned global path in parallel, perpendicular, and diagonal parking scenarios is within 0.35 m, and the distance from dynamic obstacles is greater than 2 m, which confirms that the planned path is rational.
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Authors and Affiliations

Hao Chen
1
ORCID: ORCID
Jiateng Yang
2
Xiangmei Ye
1
Weiwu Chen
2
Wenfeng Guo
3
Yuruo Wang
4
Gan Shen
5

  1. Department of Artificial Intelligence, Zhejiang Business Technology Institute, Ningbo, 315000, China
  2. School of Computer Science, City University of Hong Kong, Hong Kong, 999077, China
  3. School of Vehicle and Mobility, State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing, 100000, China
  4. Pan-Asia Technical Automotive Center Co., Ltd., Shanghai, 201805, China
  5. School of Automotive and Transportation Engineering, Hefei University of Technology, Hefei, 230000, China
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Abstract

In this paper, we propose a method for approximating ballistic curves and determining ballistic limit velocity based on a data-driven approach as a function of two variables: thickness and initial velocity, allowing for the approximation of these parameters for material thicknesses that were not present in the training set. This differs from previous work in this area, where a random division was made between the training and validation sets, which did not guarantee separability in terms of material thickness between the training and validation sets. To prove the effectiveness of this approach, we performed leave-one-out cross-validation. Our method was trained on ballistic experimental data, which was extended using the finite element method. We also proposed a new method of data oversampling based on fitted ballistic curves estimated using the Recht-Ipson method. Oversampling involves the use of stochastic sampling in which the cumulative distribution function is a mixture of uniform sampling and the first and second derivatives derived from ballistic limit curves. We have evaluated several deep neural network architectures. Our experiments have shown that it is possible not only to approximate the shape of the curve but also to accurately predict the ballistic limit velocity for material thicknesses not present in the dataset. The inclusion of information about the first and second derivatives in the stochastic oversampling process allowed for a significant increase in prediction accuracy over uniform sampling.
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Authors and Affiliations

Tomasz Hachaj
1
ORCID: ORCID
Teresa Frąś
2
ORCID: ORCID

  1. Faculty of Electrical Engineering, Automatics, Computer Science and Biomedical Engineering, AGH University of Krakow,Al. Mickiewicza 30, Krakow 30-059, Poland
  2. French-German Research Institute of Saint-Louis (ISL), 5 rue du Général Cassagnou, 68301, France