Georgi Mihalev

Dr. Georgi Mihalev

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Research Focus & Metrics

Academic Career Length

6Years (2021-Present)

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

Representative Publications

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7 October 2025 in Applied Sciences
Verified
Journal Article
Open access
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SIStefan Ivanov
Stefan Ivanov
JWJacek Lukasz Wilk-Jakubowski
Jacek Lukasz Wilk-Jakubowski
Leszek CiopińskiLeszek Ciopiński
Leszek Ciopiński
ŁPŁukasz Pawlik
Łukasz Pawlik
Grzegorz Wilk-JakubowskiGrzegorz Wilk-Jakubowski
Grzegorz Wilk-Jakubowski
GMGeorgi Mihalev
Georgi Mihalev
Electronic nose (e-nose) systems have emerged as transformative tools for odor and gas analysis, leveraging advances in nanomaterials, sensor arrays, and machine learning (ML) to mimic biological olfaction. This review synthesizes recent developments in e-nose technology, focusing on innovations in sensor design (e.g., graphene-based nanomaterials, MEMS, and optical sensors), drift compensation techniques, and AI-driven data processing. We highlight key applications across healthcare (e.g., non-invasive disease diagnostics via breath analysis), food quality monitoring (e.g., spoilage detection and authenticity verification), and environmental management (e.g., pollution tracking and wastewater treatment). Despite progress, challenges such as sensor selectivity, long-term stability, and standardization persist. The paper underscores the potential of e-noses to replace conventional analytical methods, offering portability, real-time operation, and cost-effectiveness. Future directions include scalable fabrication, robust ML models, and IoT integration to expand their practical adoption.

17 April 2025 in Journal of Imaging
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Journal Article
Open access
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Hristina StoychevaHristina Stoycheva
Hristina Stoycheva
GMGeorgi Mihalev
Georgi Mihalev
SSStanimir Mihaylov Sadinov
Stanimir Mihaylov Sadinov
KAKrasen Angelov
Krasen Angelov
This paper presents a modified image encryption scheme based on the OTP (One-Time Pad) algorithm, consisting of chaotic synchronization and artificial neural networks (ANNs) for improved security and efficiency. The scheme uses chaotic synchronization based on feedback control to create complex and unique encryption keys. Additionally, ANNs are used to approximate time functions, creating a neural encoding key, which adds an additional layer of complexity to the encryption process. The proposed scheme integrates static, chaotic, and neural keys in a multilayer structure, providing high resistance against statistical and cryptographic attacks. The results show that the proposed methodology achieves entropy values close to the theoretical maximum, effectively destroys the correlation between pixels, and demonstrates high sensitivity to variations in the input data. The proposed scheme shows very good feasibility in terms of both security and efficiency, which gives a reliable solution for secure image transmission and storage. This is proven by a study of resistance to various crypto–graphic attacks such as brute force attack, differential attack, noise and data cut attacks, key sensitivity, and computational complexity.

25 August 2025 in Engineering Proceedings
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Conference Paper
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Hristina StoychevaHristina Stoycheva
Hristina Stoycheva
GMGeorgi Mihalev
Georgi Mihalev
This paper addresses the challenge of determining optimal parameters in chaotic systems used for image encryption algorithms based on chaos theory. A baseline algorithm employing a third-order Lorenz chaotic system is examined, incorporating core procedures such as permutation (shuffling) and diffusion. Graphical results are presented to illustrate the variation of image entropy in relation to changes in system parameters. The analysis reveals a distinct region in the parameter space where entropy reaches its highest values. Based on these observations, an optimality criterion is formulated, defining an objective function that captures the entropy’s sensitivity to two key system parameters, including the bifurcation parameter. A complex objective function is derived, and the optimization problem is solved using a modified version of the Price algorithm enhanced with artificial intelligence techniques. The proposed modification demonstrates superior performance in locating the global extremum of the objective function, resulting in enhanced security of the encrypted image. Numerical and graphical results for various images are provided, along with a comparative analysis between the standard and the modified Price method.

30 September 2021
Verified
Conference Paper
Closed access
GMGeorgi Mihalev
Georgi Mihalev
SYStanimir Yordanov
Stanimir Yordanov
The article represents developed anthropomorphic robotic finger and its ability to perform complex manipulations as a part of a robotic arm. The advantages and disadvantages of this type of manipulators are defined. Using a hybrid approach, a kinematic model of the system is derived. The main functional dependences of the forward and inverse kinematic model are derived. The analysis is made on the basis of differential kinematics and the workspace of the manipulator. The developed system has been tested while performing various tasks and graphical results for some of them are presented, proving the peculiarities of the control of this type of robotic systems.

25 August 2025 in Engineering Proceedings
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Conference Paper
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GMGeorgi Mihalev
Georgi Mihalev
This article presents a hybrid approach that combines Laguerre orthonormal functions with deep neural networks (DNN) for effective approximation of impulse responses of dynamic systems. Attention is given to key limitations in approximation with Laguerre functions, such as the selection of the optimal scaling factor, the number of functions used, and computational complexity. By training compact DNNs that directly predict the decomposition coefficients, increased functionality is achieved, as well as greater flexibility and efficiency in the context of implementing MPC. The proposed architecture provides good scalability, robustness, and computational efficiency, making it applicable in tasks related to system approximation and identification under uncertainty and noise conditions.

14 January 2026 in Engineering Proceedings
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Conference Paper
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GMGeorgi Mihalev
Georgi Mihalev
SYStanimir Yordanov
Stanimir Yordanov
KOKrasimir Ormandzhiev
Krasimir Ormandzhiev
SIStefan Ivanov
Stefan Ivanov
Hristina StoychevaHristina Stoycheva
Hristina Stoycheva
This paper presents the design of a fuzzy PID controller with a parallel structure for controlling an electro-hydraulic servo system. The main factors affecting control performance in electro-hydraulic systems are discussed in detail. The proposed fuzzy controller features a specific structure obtained through a coefficient transfer approach from a classical PID controller, enabling seamless integration of the fuzzy logic component and simplifying the tuning process. Relevant mathematical equations and dependencies are provided. The closed-loop system’s stability is analyzed using the BIBO (Bounded Input, Bounded Output) criterion. The designed controller is implemented in the MATLAB/Simulink 2019 environment and tested using a real-time measurement and control system. Graphical results are presented, illustrating the performance of the closed-loop system under step and sinusoidal reference signals. The obtained results confirm the qualities and proper tuning of the implemented controller.