Levente Kovacs | Óbuda University (original) (raw)

Papers by Levente Kovacs

2013 IEEE 8th International Symposium on Applied Computational Intelligence and Informatics (SACI), 2013

Cancer fighting treatments are expanding, and a promising type, targeted molecular therapies have... more Cancer fighting treatments are expanding, and a promising type, targeted molecular therapies have a new approach. The aim of these therapies is not to eliminate the whole tumor, but to control the tumor into a given state and keep it there. Explicit knowledge of tumor growth dynamics and the effects of targeted molecular therapies is crucial in tumor treatment development. We show the results of mouse experiments where tumor growth was investigated in case of C38 colon adenocarcinoma and B16 melanoma. Several curves were fitted and tumor growth dynamics was examined. Three attributes of tumor were measured: tumor volume, tumor mass and vascularization; and tumor growth dynamics was examined. Tumor volume was measured with digital caliper, vascularization was investigated with CD31 antibody immunohistochemistry staining on frozen sections. The relationship between these tumor attributes were examined with linear regression analysis. The dynamics of tumor growth was identified as a second order linear system.

2014 IEEE 9th IEEE International Symposium on Applied Computational Intelligence and Informatics (SACI), 2014

ABSTRACT Following the tradition established at previous IEEE INES conferences, this paper presen... more ABSTRACT Following the tradition established at previous IEEE INES conferences, this paper presents the results achieved by the Physiological Controls Group of Óbuda University in the field of physiological control last year (2013). The application target was focused on diabetes (artificial pancreas), tumor (antiangiogenic therapy), and hemodialysis (control of peristaltic pumps).

2013 IEEE 17th International Conference on Intelligent Engineering Systems (INES), 2013

ABSTRACT The current paper represents a continuation of the conference papers presented at the IN... more ABSTRACT The current paper represents a continuation of the conference papers presented at the INES 2011 and 2012 conferences. A brief summary of the newest results in the field of physiological modeling and control are presented focusing on high public health impact diseases: diabetes, tumor and obesity. In the case of diabetes control, preliminary model-free results of the developed robust control framework is presented, while in the case of tumor control we have started to create a new tumor growth model based on clinical experiments. In the case of biostatistical investigation of obesity, new aspects of relationship between overweight/obesity and laboratory results was examined.

Periodica Polytechnica Electrical Engineering, 2014

c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 1 4 ( 2 0 1 4 ) e... more c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 1 4 ( 2 0 1 4 ) e98-e110 a b s t r a c t Cancer is one of the most destructive and lethal illnesses of the modern civilization. In the last decades, clinical cancer research shifted toward molecular targeted therapies which have limited side effects in comparison to conventional chemotherapy and radiation therapy. Antiangiogenic therapy is one of the most promising cancer treatment methods. The dynamical model for tumor growth under angiogenic stimulator/inhibitor control was posed by Hahnfeldt et al. in 1999; it was investigated and partly modified many times. In this paper, a modified version of the originally published model is used to describe a continuous infusion therapy. In order to generalize individualized therapies a robust control method is proposed using H ∞ methodology. Uncertainty weighting functions are determined based on the real pathophysiological case and simulations are performed on different tumor volumes to demonstrate the robustness of the proposed method.

ABSTRACT In the past decades, many new trends appeared in interventional medicine. One of the mos... more ABSTRACT In the past decades, many new trends appeared in interventional medicine. One of the most groundbreaking ones is Image-Guided Surgery (IGS). The main benefit of IGS procedures is the reduction of the patient's pain and collateral damage through improved accuracy and targeting. Electromagnetic Tracking (EMT) has been introduced to medical applications as an effective tool for navigation. However, magnetic fields can be severely distorted by ferromagnetic materials and electronic equipment, which is a major barrier towards their wider application. The focus of the study is to determine and compensate the inherent errors of the different types of EMTs, in order to improve their accuracy. Our aim is to develop a standardized, simple and repeatable assessment protocol; to determine tracking errors with sub-millimeter accuracy, hence increasing the measurement precision and reliability. For initial experiments, the NDI Aurora and the Ascension medSAFE systems were used in a standard laboratory environment. We aim to advance to the state-of-the art by describing and disseminating an easily reproducible calibration method, publishing the CAD files of the accuracy phantom and the source of the evaluation data. This should allow the wider spread of the technique, and eventually lead to the repeatable and comparable assessment of EMT systems.

2010 IEEE 14th International Conference on Intelligent Engineering Systems, 2010

NFC is one of the latest wireless communication technologies, making possible variety of business... more NFC is one of the latest wireless communication technologies, making possible variety of business opportunities. At Budapest University of Technology and Economics (BME) a generalized approach for NFC application development has been elaborated, where the Mobile Network Operators (MNOs), as well as service providers can make their own application and run it in the proposed common environment. We have developed the prototype of an application framework based on the generalized approach that provides the possibility of rapid implementation of any kind of the business logic and the user interface as well as the opportunity to create a new skin for the already existing application. Further benefit of the application framework is that the technological details are hidden from the service application developers thus they can focus only on the proper implementation of the business logic and the user interface. One of the main units of the developed framework is a script application execution environment (the so called scripting host) running on mobile equipments. The scripting host allows the user to dynamically manage and access NFC based services using the underlying mobile equipment. The current paper presents the security consideration of the script installation and execution procedures.

Engineering is a relatively new 3. Bioengineering examination of accidents, orthopedic ' interdis... more Engineering is a relatively new 3. Bioengineering examination of accidents, orthopedic ' interdisciplinary science. This paper presents the biomedical cases, rehabilitation and sport activities. Preparation of engineering activity, which is carried Out at Budapest development trends. Design and manufacture of medical University of Technology and Economics and its partner institutes. I n the first part the main goals and the curriculum of the Biomedical Engineering ducation Program is 4. Assurance of instrumental and measurement presented. The second part of the paper summarizes the most important biomedical engineering researches carried Out technological background of biomedical research. mostly in the Biomedical Engineering Laboratory of our Development and operation of routine laboratory large university. equipments, technologies, automated analyzers and robots. auxiliary materials and appliances; KepvordsBiomedical Engineering, Education 111. CURRICULUM OF BIOMEDICAL ENGiNEERiNG TRAINING 1. NTRODUCTION ' 0-7803-7789-3/03/$17.00 02003 IEEE

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009

This paper presents a novel image processing procedure dedicated to the automated detection of th... more This paper presents a novel image processing procedure dedicated to the automated detection of the medial axis of the root canal from dental micro CT records. The 3D model of root canal is built up from several hundreds of parallel cross sections, using image enhancement and segmentation, center point detection in the segmented slice, three dimensional inner surface reconstruction and morphological skeleton extraction in three dimensions. The central line of the root canal is interpolated as a 3D spline curve. The proposed procedure can help prepare several kinds of endodontic interventions.

Application of modern robust control methods using Mathematica are presented in this case-study f... more Application of modern robust control methods using Mathematica are presented in this case-study for blood glucose control of Type I diabetic patients under intensive care. The methods are applied on the minimal model of Bergman [1], using computer algebra. Two modern robust control methods are exemplified: the disturbance rejection LQ control or minimax control (as an extension of the classical LQ control) and the robust H ∞ control. It is shown the minimax control has limitations in practice, but employing reduced Gröbner basis on rational field, it is possible to approximate the theoretical solution and so getting a better solution than LQ does. In case of H ∞ control, the graphical method in frequency domain -implemented under Mathematica by [2]is extended with a disturbance rejection constraint and the robustness of the resulted high-order linear controller is demonstrated by nonlinear closed loop simulation in state-space, in case of standard meal disturbances. The symbolic and numeric computations were carried out with Mathematica 5.2 and with its CSPS Application, as well as with MATLAB 6.5.

2013 IEEE 8th International Symposium on Applied Computational Intelligence and Informatics (SACI), 2013

Cancer fighting treatments are expanding, and a promising type, targeted molecular therapies have... more Cancer fighting treatments are expanding, and a promising type, targeted molecular therapies have a new approach. The aim of these therapies is not to eliminate the whole tumor, but to control the tumor into a given state and keep it there. Explicit knowledge of tumor growth dynamics and the effects of targeted molecular therapies is crucial in tumor treatment development. We show the results of mouse experiments where tumor growth was investigated in case of C38 colon adenocarcinoma and B16 melanoma. Several curves were fitted and tumor growth dynamics was examined. Three attributes of tumor were measured: tumor volume, tumor mass and vascularization; and tumor growth dynamics was examined. Tumor volume was measured with digital caliper, vascularization was investigated with CD31 antibody immunohistochemistry staining on frozen sections. The relationship between these tumor attributes were examined with linear regression analysis. The dynamics of tumor growth was identified as a second order linear system.

2014 IEEE 9th IEEE International Symposium on Applied Computational Intelligence and Informatics (SACI), 2014

ABSTRACT Following the tradition established at previous IEEE INES conferences, this paper presen... more ABSTRACT Following the tradition established at previous IEEE INES conferences, this paper presents the results achieved by the Physiological Controls Group of Óbuda University in the field of physiological control last year (2013). The application target was focused on diabetes (artificial pancreas), tumor (antiangiogenic therapy), and hemodialysis (control of peristaltic pumps).

2013 IEEE 17th International Conference on Intelligent Engineering Systems (INES), 2013

ABSTRACT The current paper represents a continuation of the conference papers presented at the IN... more ABSTRACT The current paper represents a continuation of the conference papers presented at the INES 2011 and 2012 conferences. A brief summary of the newest results in the field of physiological modeling and control are presented focusing on high public health impact diseases: diabetes, tumor and obesity. In the case of diabetes control, preliminary model-free results of the developed robust control framework is presented, while in the case of tumor control we have started to create a new tumor growth model based on clinical experiments. In the case of biostatistical investigation of obesity, new aspects of relationship between overweight/obesity and laboratory results was examined.

Periodica Polytechnica Electrical Engineering, 2014

c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 1 4 ( 2 0 1 4 ) e... more c o m p u t e r m e t h o d s a n d p r o g r a m s i n b i o m e d i c i n e 1 1 4 ( 2 0 1 4 ) e98-e110 a b s t r a c t Cancer is one of the most destructive and lethal illnesses of the modern civilization. In the last decades, clinical cancer research shifted toward molecular targeted therapies which have limited side effects in comparison to conventional chemotherapy and radiation therapy. Antiangiogenic therapy is one of the most promising cancer treatment methods. The dynamical model for tumor growth under angiogenic stimulator/inhibitor control was posed by Hahnfeldt et al. in 1999; it was investigated and partly modified many times. In this paper, a modified version of the originally published model is used to describe a continuous infusion therapy. In order to generalize individualized therapies a robust control method is proposed using H ∞ methodology. Uncertainty weighting functions are determined based on the real pathophysiological case and simulations are performed on different tumor volumes to demonstrate the robustness of the proposed method.

ABSTRACT In the past decades, many new trends appeared in interventional medicine. One of the mos... more ABSTRACT In the past decades, many new trends appeared in interventional medicine. One of the most groundbreaking ones is Image-Guided Surgery (IGS). The main benefit of IGS procedures is the reduction of the patient's pain and collateral damage through improved accuracy and targeting. Electromagnetic Tracking (EMT) has been introduced to medical applications as an effective tool for navigation. However, magnetic fields can be severely distorted by ferromagnetic materials and electronic equipment, which is a major barrier towards their wider application. The focus of the study is to determine and compensate the inherent errors of the different types of EMTs, in order to improve their accuracy. Our aim is to develop a standardized, simple and repeatable assessment protocol; to determine tracking errors with sub-millimeter accuracy, hence increasing the measurement precision and reliability. For initial experiments, the NDI Aurora and the Ascension medSAFE systems were used in a standard laboratory environment. We aim to advance to the state-of-the art by describing and disseminating an easily reproducible calibration method, publishing the CAD files of the accuracy phantom and the source of the evaluation data. This should allow the wider spread of the technique, and eventually lead to the repeatable and comparable assessment of EMT systems.

2010 IEEE 14th International Conference on Intelligent Engineering Systems, 2010

NFC is one of the latest wireless communication technologies, making possible variety of business... more NFC is one of the latest wireless communication technologies, making possible variety of business opportunities. At Budapest University of Technology and Economics (BME) a generalized approach for NFC application development has been elaborated, where the Mobile Network Operators (MNOs), as well as service providers can make their own application and run it in the proposed common environment. We have developed the prototype of an application framework based on the generalized approach that provides the possibility of rapid implementation of any kind of the business logic and the user interface as well as the opportunity to create a new skin for the already existing application. Further benefit of the application framework is that the technological details are hidden from the service application developers thus they can focus only on the proper implementation of the business logic and the user interface. One of the main units of the developed framework is a script application execution environment (the so called scripting host) running on mobile equipments. The scripting host allows the user to dynamically manage and access NFC based services using the underlying mobile equipment. The current paper presents the security consideration of the script installation and execution procedures.

Engineering is a relatively new 3. Bioengineering examination of accidents, orthopedic ' interdis... more Engineering is a relatively new 3. Bioengineering examination of accidents, orthopedic ' interdisciplinary science. This paper presents the biomedical cases, rehabilitation and sport activities. Preparation of engineering activity, which is carried Out at Budapest development trends. Design and manufacture of medical University of Technology and Economics and its partner institutes. I n the first part the main goals and the curriculum of the Biomedical Engineering ducation Program is 4. Assurance of instrumental and measurement presented. The second part of the paper summarizes the most important biomedical engineering researches carried Out technological background of biomedical research. mostly in the Biomedical Engineering Laboratory of our Development and operation of routine laboratory large university. equipments, technologies, automated analyzers and robots. auxiliary materials and appliances; KepvordsBiomedical Engineering, Education 111. CURRICULUM OF BIOMEDICAL ENGiNEERiNG TRAINING 1. NTRODUCTION ' 0-7803-7789-3/03/$17.00 02003 IEEE

2009 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2009

This paper presents a novel image processing procedure dedicated to the automated detection of th... more This paper presents a novel image processing procedure dedicated to the automated detection of the medial axis of the root canal from dental micro CT records. The 3D model of root canal is built up from several hundreds of parallel cross sections, using image enhancement and segmentation, center point detection in the segmented slice, three dimensional inner surface reconstruction and morphological skeleton extraction in three dimensions. The central line of the root canal is interpolated as a 3D spline curve. The proposed procedure can help prepare several kinds of endodontic interventions.

Application of modern robust control methods using Mathematica are presented in this case-study f... more Application of modern robust control methods using Mathematica are presented in this case-study for blood glucose control of Type I diabetic patients under intensive care. The methods are applied on the minimal model of Bergman [1], using computer algebra. Two modern robust control methods are exemplified: the disturbance rejection LQ control or minimax control (as an extension of the classical LQ control) and the robust H ∞ control. It is shown the minimax control has limitations in practice, but employing reduced Gröbner basis on rational field, it is possible to approximate the theoretical solution and so getting a better solution than LQ does. In case of H ∞ control, the graphical method in frequency domain -implemented under Mathematica by [2]is extended with a disturbance rejection constraint and the robustness of the resulted high-order linear controller is demonstrated by nonlinear closed loop simulation in state-space, in case of standard meal disturbances. The symbolic and numeric computations were carried out with Mathematica 5.2 and with its CSPS Application, as well as with MATLAB 6.5.