@article{MTMT:34836703, title = {Impedance and Dielectric Analysis of Nickel Ferrites: Revealing the Role of the Constant Phase Element and Yttrium Doping}, url = {https://m2.mtmt.hu/api/publication/34836703}, author = {Šiljegović, M. and Cvejić, Ž. and Jankov, S. and Toth, E. and Herceg, D. and Odry, Péter and Tadity, Vladimir}, doi = {10.3390/electronics13081496}, journal = {ELECTRONICS (SWITZ)}, volume = {13}, unique-id = {34836703}, year = {2024}, eissn = {2079-9292} } @article{MTMT:34547851, title = {Double-Layer Coils Design for 11 kW Wireless Power Transfer}, url = {https://m2.mtmt.hu/api/publication/34547851}, author = {Herceg, Dejana and Rajs, Vladimir and Despotović, Živadin and Popadić, Bane and Šiljegović, Mirjana and Király, Zoltán and Vizvári, Zoltán Ákos and Wizner, Krisztián and Felde, Imre and Odry, Péter and Tadity, Vladimir}, doi = {10.3390/electronics13030547}, journal = {ELECTRONICS (SWITZ)}, volume = {13}, unique-id = {34547851}, abstract = {The design of a wireless power transfer system with double rectangular coils for 11 kW power transfer is considered. System modeling and numerical calculation of the system parameters are described. Coils are made from available Litz wire, which has a smaller than necessary diameter for the required power. Thus, a setup with double layer coils was developed, which resulted in a modified design. Starting from a system consisting of coupled coils, as suggested by the standard for wireless power transfer Level 3 in class Z1, different coil and ferrite shield layouts were tested in numerical simulations, and their parameters were calculated. The prototype was constructed based on the simulated model with the best results and properties. Numerical results were verified by laboratory measurements, and a successful power transfer at 11 kW was achieved.}, year = {2024}, eissn = {2079-9292}, orcid-numbers = {Rajs, Vladimir/0000-0003-4357-770X; Despotović, Živadin/0000-0001-7277-9453} } @article{MTMT:34496311, title = {Dead-Time Effect in Inverters on Wireless Power Transfer}, url = {https://m2.mtmt.hu/api/publication/34496311}, author = {Rajs, Vladimir and Herceg, Dejana and Despotović, Živadin and Bogdanović, Miroslav and Šiljegović, Mirjana and Popadić, Bane and Kiraly, Zoltan and Vizvári, Zoltán Ákos and Sári, Zoltán and Klincsik, Mihály and Felde, Imre and Odry, Péter and Tadity, Vladimir}, doi = {10.3390/electronics13020304}, journal = {ELECTRONICS (SWITZ)}, volume = {13}, unique-id = {34496311}, abstract = {This paper presents a comprehensive analysis of the dead-time effects in wireless power transfer systems based on LCC-S topology. In these systems operating at high frequencies, the ratio of dead-time versus the operating period becomes critical, and the dead-time issue can cause certain problems regarding power quality, efficiency, and output voltage ripple. The impact of input quantities such as voltage and switching frequency on the efficiency and output power of the LCC-S-tuned WPT system was also investigated. The optimal combination of these parameters used to achieve the maximum efficiency for a target output power and to set the appropriate value of the dead time were determined by running multiple simulations using the MATLAB R2023b software platform. It was also shown that the output voltage remained unchanged with and without a load and up to 1200 ns of dead-time, which provides a simple implementation of the corresponding mathematical model. In the recommended interval of 600–1500 ns, the influence of the dead-time on the value of the output voltage amplitude is less than 10%. The validity of the proposed method was confirmed through the implementation of the experimental prototype, a 5 kW wireless power transmission system, and the obtained results were in accordance with the simulation results.}, year = {2024}, eissn = {2079-9292}, orcid-numbers = {Rajs, Vladimir/0000-0003-4357-770X; Despotović, Živadin/0000-0001-7277-9453; Kiraly, Zoltan/0000-0002-6808-3856} } @article{MTMT:34448557, title = {Continuous Electrode Models and Application of Exact Schemes in Modeling of Electrical Impedance Measurements}, url = {https://m2.mtmt.hu/api/publication/34448557}, author = {Vizvári, Zoltán Ákos and Klincsik, Mihály and Odry, Péter and Tadity, Vladimir and Győrfi, Nina Rubina and Tóth, Attila and Sári, Zoltán}, doi = {10.3390/electronics13010066}, journal = {ELECTRONICS (SWITZ)}, volume = {13}, unique-id = {34448557}, abstract = {The crucial issue in electrical impedance (EI) measurements lies in the galvanic interaction between the electrodes and the investigated material. This paper brings together the basic and applied research experience and combines their results with excellent properties. Consequently, innovative precise methodologies have emerged, enabling the direct modeling of EI measurements, free from the inaccuracies often associated with numerical approaches. As an outcome of the efficiency and robustness of the applied method, the conductivity of the material and the electrodes are represented by a common piecewise function, which is used to solve the differential equation modeling of the EI measurement. Moreover, this allows the possibility for modeling the conductivity of electrodes with continuous functions, providing an important generalization of the Complete Electrode Model (CEM), which has been widely used so far. The effectiveness of the novel approach was showcased through two distinct case studies. In the first case study, potential functions within both the material and the electrodes were computed using the CEM. In the second case study, calculations were performed utilizing the newly introduced continuous electrode model. The simulation results suggest that the new method is a powerful tool for biological research, from in vitro experiments to animal studies and human applications.}, year = {2024}, eissn = {2079-9292} } @article{MTMT:34124226, title = {Novel Noninvasive Paraclinical Study Method for Investigation of Liver Diseases}, url = {https://m2.mtmt.hu/api/publication/34124226}, author = {Győrfi, Nina Rubina and Gál, Adrián Róbert and Fincsur, András and Kalmar-Nagy, Karoly and Mintál, Kitti and Hormay, Edina and Miseta, Attila János and Tornóczky, Tamás and Nemeth, Anita K. and Bogner, Péter and Kiss, Tamas and Helyes, Zsuzsanna and Sári, Zoltán and Klincsik, Mihály and Tadity, Vladimir and Lénárd, László and Vereczkei, András and Karádi, Zoltán György and Vizvári, Zoltán Ákos and Tóth, Attila}, doi = {10.3390/biomedicines11092449}, journal-iso = {BIOMEDICINES}, journal = {BIOMEDICINES}, volume = {11}, unique-id = {34124226}, abstract = {Based on a prior university patent, the authors developed a novel type of bioimpedance-based test method to noninvasively detect nonalcoholic fatty liver disease (NAFLD). The development of a new potential NAFLD diagnostic procedure may help to understand the underlying mechanisms between NAFLD and severe liver diseases with a painless and easy-to-use paraclinical examination method, including the additional function to detect even the earlier stages of liver disease. The aim of this study is to present new results and the experiences gathered in relation to NAFLD progress during animal model and human clinical trials.}, keywords = {VALIDATION; clinical study; hepatic steatosis; Wistar; Bioelectrical impedance spectroscopy; NAFLD; noninvasive measurement; low-frequency measurement}, year = {2023}, eissn = {2227-9059}, orcid-numbers = {Mintál, Kitti/0009-0003-4739-2902; Hormay, Edina/0009-0004-0598-5061; Miseta, Attila János/0000-0002-7984-3347} } @article{MTMT:34079171, title = {Online Outdoor Terrain Classification Algorithm for Wheeled Mobile Robots Equipped with Inertial and Magnetic Sensors}, url = {https://m2.mtmt.hu/api/publication/34079171}, author = {Sarcevic, Péter and Csík, Dominik Miklós and Pesti, Richárd and Stančin, Sara and Tomažič, Sašo and Tadity, Vladimir and Rodriguez-Resendiz, Juvenal and Sárosi, József and Odry, Ákos}, doi = {10.3390/electronics12153238}, journal = {ELECTRONICS (SWITZ)}, volume = {12}, unique-id = {34079171}, abstract = {Terrain classification provides valuable information for both control and navigation algorithms of wheeled mobile robots. In this paper, a novel online outdoor terrain classification algorithm is proposed for wheeled mobile robots. The algorithm is based on only time-domain features with both low computational and low memory requirements, which are extracted from the inertial and magnetic sensor signals. Multilayer perceptron (MLP) neural networks are applied as classifiers. The algorithm is tested on a measurement database collected using a prototype measurement system for various outdoor terrain types. Different datasets were constructed based on various setups of processing window sizes, used sensor types, and robot speeds. To examine the possibilities of the three applied sensor types in the application, the features extracted from the measurement data of the different sensors were tested alone, in pairs and fused together. The algorithm is suitable to operate online on the embedded system of the mobile robot. The achieved results show that using the applied time-domain feature set the highest classification efficiencies on unknown data can be above 98%. It is also shown that the gyroscope provides higher classification rates than the widely used accelerometer. The magnetic sensor alone cannot be effectively used but fusing the data of this sensor with the data of the inertial sensors can improve the performance.}, year = {2023}, eissn = {2079-9292}, orcid-numbers = {Sarcevic, Péter/0000-0003-4050-8231; Stančin, Sara/0000-0002-8569-0498; Rodriguez-Resendiz, Juvenal/0000-0001-8598-5600; Sárosi, József/0000-0002-6303-5011} } @article{MTMT:34037447, title = {General Exact Schemes for Second-Order Linear Differential Equations Using the Concept of Local Green Functions}, url = {https://m2.mtmt.hu/api/publication/34037447}, author = {Vizvári, Zoltán Ákos and Klincsik, Mihály and Odry, Péter and Tadity, Vladimir and Sári, Zoltán}, doi = {10.3390/axioms12070633}, journal-iso = {AXIOMS}, journal = {AXIOMS}, volume = {12}, unique-id = {34037447}, abstract = {In this paper, we introduce a special system of linear equations with a symmetric, tridiagonal matrix, whose solution vector contains the values of the analytical solution of the original ordinary differential equation (ODE) in grid points. Further, we present the derivation of an exact scheme for an arbitrary mesh grid and prove that its application can completely avoid other errors in discretization and numerical methods. The presented method is constructed on the basis of special local green functions, whose special properties provide the possibility to invert the differential operator of the ODE. Thus, the newly obtained results provide a general, exact solution method for the second-order ODE, which is also effective for obtaining the arbitrary grid, Dirichlet, and/or Neumann boundary conditions. Both the results obtained and the short case study confirm that the use of the exact scheme is efficient and straightforward even for ODEs with discontinuity functions.}, year = {2023}, eissn = {2075-1680} } @article{MTMT:33787514, title = {Lumped Element Method Based Conductivity Reconstruction Algorithm for Localization Using Symmetric Discrete Operators on Coarse Meshes}, url = {https://m2.mtmt.hu/api/publication/33787514}, author = {Sári, Zoltán and Klincsik, Mihály and Odry, Péter and Tadity, Vladimir and Tóth, Attila and Vizvári, Zoltán Ákos}, doi = {10.3390/sym15051008}, journal-iso = {SYMMETRY-BASEL}, journal = {SYMMETRY (BASEL)}, volume = {15}, unique-id = {33787514}, abstract = {The inverse conductivity problem in electrical impedance tomography involves the solving of a nonlinear and under-determined system of equations. This paper presents a new approach, which leads to a quadratic and overdetermined system of equations. The aim of the paper is to establish new research directions in handling of the inverse conductivity problem. The basis of the proposed method is that the material, which can be considered as an isotropic continuum, is modeled as a linear network with concentrated parameters. The weights of the obtained graph represent the properties of the discretized continuum. Further, the application of the developed procedure allows for the dielectric constant to be used in the multi-frequency approach, as a result of which the optimized system of equations always remains overdetermined. Through case studies, the efficacy of the reconstruction method by changing the mesh resolution applied for discretizing is presented and evaluated. The presented results show, that, due to the application of discrete, symmetric mathematical structures, the new approach even at coarse mesh resolution is capable of localizing the inhomogeneities of the material.}, year = {2023}, eissn = {2073-8994} } @{MTMT:32590342, title = {BIOIMPEDANCIA MONITORING MÉRÉSIADATAINAK NÉPEGÉSZSÉGÜGYI SZEMPONTÚ ELEMZÉSE}, url = {https://m2.mtmt.hu/api/publication/32590342}, author = {Csibi, Katalin}, booktitle = {SZAKDOLGOZAT ABSZTRAKTKÖTET III.}, unique-id = {32590342}, year = {2019}, pages = {6-8} }