Viktor Khavalko

Dr. Viktor Khavalko

orcid

Research Focus & Metrics

Academic Career Length

11Years (2016-Present)

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

Representative Publications

View All Publications
1 August 2018
Verified
Conference Paper
Closed access
ITIvan Tsmots
Ivan Tsmots
YTYurii Tsymbal
Yurii Tsymbal
VKViktor Khavalko
Viktor Khavalko
OSOleksa Skorokhoda
Oleksa Skorokhoda
TTTaras Tesluyk
Taras Tesluyk
The “model of successive geometric transformations” paradigm has been adapted for the implementation of parallel-streaming neural network encryption-decryption of data in real time. A model and structure of a parallel-streaming neural-like element for the mode have been developed.

1 July 2019
Verified
Conference Paper
Closed access
VKViktor Khavalko
Viktor Khavalko
ITIvan Tsmots
Ivan Tsmots
The problem of images classification is considered. It is proposed to use the autoassociative neural networks based on the model of successive geometric transformations for this problem solving. The advantages and disadvantages of this approach are considered, as well as ways to improve the accuracy of image classification.

1 October 2018
Verified
Conference Paper
Closed access
VKViktor Khavalko
Viktor Khavalko
AKAndrew Khudyy
Andrew Khudyy
The questions of neural networks usage for cryptographic information protection have been considered. The problem of cryptographic stability and the main reasons for the unreliability of cryptosystems have been investigated. The issue of neurocomputers application in cryptanalysis is considered. The analysis of the neurocomputers work based on the developed software is done.

1 February 2016
Verified
Conference Paper
Closed access
OKOlena Krasko
Olena Krasko
RKRoman Kolodiy
Roman Kolodiy
VKViktor Khavalko
Viktor Khavalko
Currently optical access networks are developing towards new converged architecture. Network convergence allows to integrate multiple access networks with different purposes such as home area network, enterprise network and mobile backhaul network. In this paper, we propose a new algorithm of wavelengths rearrangement and load balancing (WRLB) based on optical wavelength-time division multiple access (OWTDMA). Proposed algorithm improves the flexibility, scalability and energy efficiency of optical access network by using time-frequency resource blocks for frames transmission.

16 October 2024
Verified
Conference Paper
Closed access
VKViktor Khavalko
Viktor Khavalko
OVOleksandr Vlasyuk
Oleksandr Vlasyuk
Class imbalance is a prevalent challenge in machine learning, particularly in domains like credit risk assessment, fraud detection, and medical diagnosis, where the minority class often represents the critical cases of interest. Traditional machine learning models tend to be biased towards the majority class, leading to suboptimal performance in detecting minority class instances. This paper explores various strategies to mitigate the effects of class imbalance, including performance metric adjustments, resampling techniques such as oversampling, undersampling, and Synthetic Minority oversampling Technique (SMOTE), as well as algorithmic modifications. We propose different hybrid approaches that combines Random Forest with Laplace regularization and others to enhance the classification of minority classes in imbalanced datasets. Our approach is validated using a credit risk dataset, where the proposed method demonstrates significant improvements in recall and F1 scores compared to baseline models, suggesting its effectiveness in addressing class imbalance in critical applications.

29 December 2025 in Bulletin of National Technical University "KhPI". Series: System Analysis, Control and Information Technologies
Verified
Journal Article
Open access
PDF file
BDBohdan Dokhniak
Bohdan Dokhniak
VKViktor Khavalko
Viktor Khavalko
Traffic flow prediction remains a cornerstone of intelligent transportation systems (ITS), facilitating congestion mitigation, route optimization, and sustainable urban planning. Graph Neural Networks (GNNs) have revolutionized this domain by adeptly modeling the intricate graph-structured nature of traffic networks, where nodes represent sensors or intersections and edges denote spatial relationships. Recent years (2023–2025) have witnessed a surge in scientific innovation, with several novel approaches pushing the boundaries of traffic prediction accuracy and robustness. Notably, hybrid GNN-Transformer architectures have emerged, leveraging the spatial reasoning of GNNs and the temporal sequence modeling power of Transformers to capture long-range dependencies and complex spatiotemporal patterns. Physics-informed GNNs integrate domain knowledge, such as conservation laws and traffic flow theory, directly into the learning process, enhancing interpretability and generalization to unseen scenarios. Uncertainty-aware frameworks, including Bayesian GNNs and ensemble methods, provide probabilistic forecasts, crucial for risk-sensitive applications and adaptive traffic management in volatile urban environments. This article provides a comprehensive guide to implementing GNNs for traffic flow prediction, detailing best practices in data preparation (e.g., graph construction, feature engineering, handling missing data), model training (e.g., loss functions, regularization, hyperparameter tuning), and real-time deployment (e.g., edge computing, latency optimization). We critically compare GNNs to traditional statistical and deep learning methods, highlighting their superior ability to capture non-Euclidean spatial dependencies, adapt to dynamic and evolving network topologies, and seamlessly integrate multi-modal data sources such as weather, events, and sensor readings. Empirical evidence from widely used benchmarks, including PeMS and METR-LA, demonstrates that state-of-the-art GNN models achieve up to 15–20 % improvements in accuracy metrics such as Mean Absolute Error (MAE) and Root Mean Square Error (RMSE) over conventional baselines. These gains are attributed to the models’ capacity for dynamic graph learning, attention-based feature selection, and robust handling of heterogeneous data. Drawing on these recent innovations, this synthesis highlights GNNs' pivotal role in fostering resilient, AI-driven traffic systems for future smart cities, setting the stage for next-generation ITS solutions that are adaptive, interpretable, and scalable. In addition to these advancements, the integration of real-time sensor data and external information sources has further improved the responsiveness of traffic prediction models. Modern GNN frameworks are capable of handling large-scale urban networks, making them suitable for deployment in metropolitan areas with complex road infrastructures. The use of transfer learning and domain adaptation techniques allows models trained in one city to be effectively applied to others, reducing the need for extensive retraining. Furthermore, explainable AI approaches within GNNs are gaining traction, enabling stakeholders to understand and trust model decisions in critical traffic management scenarios. Recent research also explores the fusion of GNNs with reinforcement learning, enabling adaptive control strategies for traffic signals and congestion pricing. The scalability of GNNs ensures that they can process data from thousands of sensors in real time, supporting city-wide traffic optimization. Advances in hardware acceleration, such as GPU and edge computing, have made it feasible to deploy these models in latency-sensitive environments. Collaborative efforts between academia, industry, and government agencies are driving the adoption of GNN-based solutions in smart city initiatives. As urban mobility continues to evolve, the ability of GNNs to incorporate emerging data modalities, such as connected vehicle telemetry and mobile device traces, will be crucial for future developments. The ongoing refinement of model architectures and training protocols promises even greater accuracy and robustness in traffic flow prediction. Ultimately, the convergence of GNNs with other AI technologies is set to transform intelligent transportation systems, paving the way for safer, more efficient, and sustainable urban mobility.