TY  - CONF
AU  - Atanasoski, Vladimir
AU  - Lazović, Aleksandar
AU  - Ivanović, Marija
AU  - Hadžievski, Ljupčo
AU  - Bojović, Boško
AU  - Petrović, Jovana
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13045
AB  - Photoplethysmography (PPG) has become a standard method for assessment of blood volume changes in clinical care and heart rate in home care [1]. Besides the pulse rate, PPG pulse forms carry signatures of diagnostically relevant events in cardiac cycle and can be used to estimate arterial stiffness. Extraction of these features requires removal of noise, motion artifacts and the superimposed slow varying signals, such as that from breathing, from the signal while preserving pulse morphology. However, modern filtering methods often fail to reproduce all signal features. Here, we propose a novel noise–removal method based on autocorrelation. Autocorrelation is a well-known method used in optics, mainly for estimating the duration of ultrashort laser pulses. We used autocorrelation to remove the noise and baseline wander (BLW) from a set of bioelectrical signals, namely electrocardiogram (ECG) and PPG. These signals comprise pulses (or beats) repeated in time but with slight changes. When we record several such beats and by averaging them get a noise-free signal with distorted morphology. However, taking a few steps further, namely subtracting the average from the original signal and filtering the difference in the frequency domain, enables the noise and BLW extraction from the original signal and reproduction of a faithful noise-free signal. We tested this method on the private ECG database, where added BLW component is from public MIT-NST database, and on the private PPG signals. The results show the superiority of our approach compared to the conventional cubic spline (CSP) method.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Autocorrelation for denoising biomedical signals
SP  - 25
EP  - 25
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13045
ER  - 

@conference{
author = "Atanasoski, Vladimir and Lazović, Aleksandar and Ivanović, Marija and Hadžievski, Ljupčo and Bojović, Boško and Petrović, Jovana",
year = "2023",
abstract = "Photoplethysmography (PPG) has become a standard method for assessment of blood volume changes in clinical care and heart rate in home care [1]. Besides the pulse rate, PPG pulse forms carry signatures of diagnostically relevant events in cardiac cycle and can be used to estimate arterial stiffness. Extraction of these features requires removal of noise, motion artifacts and the superimposed slow varying signals, such as that from breathing, from the signal while preserving pulse morphology. However, modern filtering methods often fail to reproduce all signal features. Here, we propose a novel noise–removal method based on autocorrelation. Autocorrelation is a well-known method used in optics, mainly for estimating the duration of ultrashort laser pulses. We used autocorrelation to remove the noise and baseline wander (BLW) from a set of bioelectrical signals, namely electrocardiogram (ECG) and PPG. These signals comprise pulses (or beats) repeated in time but with slight changes. When we record several such beats and by averaging them get a noise-free signal with distorted morphology. However, taking a few steps further, namely subtracting the average from the original signal and filtering the difference in the frequency domain, enables the noise and BLW extraction from the original signal and reproduction of a faithful noise-free signal. We tested this method on the private ECG database, where added BLW component is from public MIT-NST database, and on the private PPG signals. The results show the superiority of our approach compared to the conventional cubic spline (CSP) method.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Autocorrelation for denoising biomedical signals",
pages = "25-25",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13045"
}

Atanasoski, V., Lazović, A., Ivanović, M., Hadžievski, L., Bojović, B.,& Petrović, J.. (2023). Autocorrelation for denoising biomedical signals. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 25-25.
https://hdl.handle.net/21.15107/rcub_vinar_13045

Atanasoski V, Lazović A, Ivanović M, Hadžievski L, Bojović B, Petrović J. Autocorrelation for denoising biomedical signals. in 16th Photonics Workshop : Book of abstracts. 2023;:25-25.
https://hdl.handle.net/21.15107/rcub_vinar_13045 .

Atanasoski, Vladimir, Lazović, Aleksandar, Ivanović, Marija, Hadžievski, Ljupčo, Bojović, Boško, Petrović, Jovana, "Autocorrelation for denoising biomedical signals" in 16th Photonics Workshop : Book of abstracts (2023):25-25,
https://hdl.handle.net/21.15107/rcub_vinar_13045 .

TY  - CONF
AU  - Tadić, Predrag
AU  - Petrović, Jovana
AU  - Đorđević, Natalija
AU  - Ivanović, Marija
AU  - Lazović, Aleksandar
AU  - Vukčević, Vladan
AU  - Ristić, Arsen
AU  - Hadžievski, Ljupčo
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/13044
AB  - We present our progress on the “Multi-SENSor SysteM and ARTificial intelligence in service of heart failure diagnosis (SensSmart)” project, which was introduced at the last year’s edition of the Workshop [1]. The goal of the SensSmart project is to enable early diagnosis of heart failure, through the development of: 1) a multi-sensor polycardiograph apparatus (PCG) that produces simultaneous acquisition of the subject’s electrocardiogram (ECG), photoplethysmogram (PPG), heart sounds, and heart movements, and 2) AI-assisted analysis of the acquired signals. This presentation is going to focus on the acquisition and processing of PPG signals. PPG is obtained by using a pulse oximeter which illuminates the skin and measures the changes in light absorption, thereby enabling the detection of blood volume changes in the vessels. Our PCG apparatus measures the blood flow through the brachial, radial, and carotid arteries. During each heartbeat, the generated waveform typically exhibits several characteristic points [2]. The magnitudes and time distances between these points are useful indicators of many cardiac conditions, including heart failure [3]. However, the inter-patient variability of the PPG waveform makes it challenging to derive simple rule-based diagnostic procedures. This has led many researchers to turn to statistical or machine learning methods for processing of PPG signals [4].  In this presentation, we give an overview of AI-based signal processing methods for PPG, and present some preliminary results and challenges in extracting features from real-world signals obtained using our PCG.
PB  - Belgrade : Institute of Physics
C3  - 16th Photonics Workshop : Book of abstracts
T1  - Photoplethysmogram as a source of biomarkers  for AI-based diagnosis of heart failure
SP  - 24
EP  - 24
UR  - https://hdl.handle.net/21.15107/rcub_vinar_13044
ER  - 

@conference{
author = "Tadić, Predrag and Petrović, Jovana and Đorđević, Natalija and Ivanović, Marija and Lazović, Aleksandar and Vukčević, Vladan and Ristić, Arsen and Hadžievski, Ljupčo",
year = "2023",
abstract = "We present our progress on the “Multi-SENSor SysteM and ARTificial intelligence in service of heart failure diagnosis (SensSmart)” project, which was introduced at the last year’s edition of the Workshop [1]. The goal of the SensSmart project is to enable early diagnosis of heart failure, through the development of: 1) a multi-sensor polycardiograph apparatus (PCG) that produces simultaneous acquisition of the subject’s electrocardiogram (ECG), photoplethysmogram (PPG), heart sounds, and heart movements, and 2) AI-assisted analysis of the acquired signals. This presentation is going to focus on the acquisition and processing of PPG signals. PPG is obtained by using a pulse oximeter which illuminates the skin and measures the changes in light absorption, thereby enabling the detection of blood volume changes in the vessels. Our PCG apparatus measures the blood flow through the brachial, radial, and carotid arteries. During each heartbeat, the generated waveform typically exhibits several characteristic points [2]. The magnitudes and time distances between these points are useful indicators of many cardiac conditions, including heart failure [3]. However, the inter-patient variability of the PPG waveform makes it challenging to derive simple rule-based diagnostic procedures. This has led many researchers to turn to statistical or machine learning methods for processing of PPG signals [4].  In this presentation, we give an overview of AI-based signal processing methods for PPG, and present some preliminary results and challenges in extracting features from real-world signals obtained using our PCG.",
publisher = "Belgrade : Institute of Physics",
journal = "16th Photonics Workshop : Book of abstracts",
title = "Photoplethysmogram as a source of biomarkers  for AI-based diagnosis of heart failure",
pages = "24-24",
url = "https://hdl.handle.net/21.15107/rcub_vinar_13044"
}

Tadić, P., Petrović, J., Đorđević, N., Ivanović, M., Lazović, A., Vukčević, V., Ristić, A.,& Hadžievski, L.. (2023). Photoplethysmogram as a source of biomarkers  for AI-based diagnosis of heart failure. in 16th Photonics Workshop : Book of abstracts
Belgrade : Institute of Physics., 24-24.
https://hdl.handle.net/21.15107/rcub_vinar_13044

Tadić P, Petrović J, Đorđević N, Ivanović M, Lazović A, Vukčević V, Ristić A, Hadžievski L. Photoplethysmogram as a source of biomarkers  for AI-based diagnosis of heart failure. in 16th Photonics Workshop : Book of abstracts. 2023;:24-24.
https://hdl.handle.net/21.15107/rcub_vinar_13044 .

Tadić, Predrag, Petrović, Jovana, Đorđević, Natalija, Ivanović, Marija, Lazović, Aleksandar, Vukčević, Vladan, Ristić, Arsen, Hadžievski, Ljupčo, "Photoplethysmogram as a source of biomarkers  for AI-based diagnosis of heart failure" in 16th Photonics Workshop : Book of abstracts (2023):24-24,
https://hdl.handle.net/21.15107/rcub_vinar_13044 .

TY  - JOUR
AU  - Shvilkin, Alexei
AU  - Vukajlović, Dejan
AU  - Bojović, Boško P.
AU  - Hadžievski, Ljupčo
AU  - Vajdic, Branislav
AU  - Atanasoski, Vladimir
AU  - Miletić, Marjan
AU  - Zimetbaum, Peter J.
AU  - Gibson, C. Michael
AU  - Vukčević, Vladan
PY  - 2023
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12393
AB  - Background Early coronary occlusion detection by portable personal device with limited number of electrocardiographic (ECG) leads might shorten symptom-to-balloon time in acute coronary syndromes.  Objectives The purpose of this study was to compare the accuracy of coronary occlusion detection using vectorcardgiographic analysis of a near-orthogonal 3-lead ECG configuration suitable for credit card-size personal device integration with automated and human 12 lead ECG interpretation.  Methods The 12-lead ECGs with 3 additional leads (“abc”) using 2 arm and 2 left parasternal electrodes were recorded in 66 patients undergoing percutaneous coronary intervention prior to (“baseline”, n = 66), immediately before (“preinflation”, n = 66), and after 90-second balloon coronary occlusion (“inflation”, n = 120). Performance of computer-measured ST-segment shift on vectorcardgiographic loops constructed from “abc” and 12 leads, standard 12-lead ECG, and consensus human interpretation in coronary occlusion detection were compared in “comparative” and “spot” modes (with/without reference to “baseline”) using areas under ROC curves (AUC), reliability, and sensitivity/specificity analysis.  Results Comparative “abc”-derived ST-segment shift was similar to two 12-lead methods (vector/traditional) in detecting balloon coronary occlusion (AUC = 0.95, 0.96, and 0.97, respectively, P = NS). Spot “abc” and 12-lead measurements (AUC = 0.72, 0.77, 0.68, respectively, P = NS) demonstrated poorer performance (P < 0.01 vs comparative measurements). Reliability analysis demonstrated comparative automated measurements in “good” agreement with reference (preinflation/inflation), while comparative human interpretation was in “moderate” range. Spot automated and human reading showed “poor” agreement.  Conclusions Vectorcardiographic ST-segment analysis using baseline comparison of 3-lead ECG system suitable for credit card-size personal device integration is similar to established 12-lead ECG methods in detecting balloon coronary occlusion.
T2  - JACC: Advances
T1  - Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration
VL  - 2
IS  - 6
SP  - 100454
DO  - 10.1016/j.jacadv.2023.100454
ER  - 

@article{
author = "Shvilkin, Alexei and Vukajlović, Dejan and Bojović, Boško P. and Hadžievski, Ljupčo and Vajdic, Branislav and Atanasoski, Vladimir and Miletić, Marjan and Zimetbaum, Peter J. and Gibson, C. Michael and Vukčević, Vladan",
year = "2023",
abstract = "Background Early coronary occlusion detection by portable personal device with limited number of electrocardiographic (ECG) leads might shorten symptom-to-balloon time in acute coronary syndromes.  Objectives The purpose of this study was to compare the accuracy of coronary occlusion detection using vectorcardgiographic analysis of a near-orthogonal 3-lead ECG configuration suitable for credit card-size personal device integration with automated and human 12 lead ECG interpretation.  Methods The 12-lead ECGs with 3 additional leads (“abc”) using 2 arm and 2 left parasternal electrodes were recorded in 66 patients undergoing percutaneous coronary intervention prior to (“baseline”, n = 66), immediately before (“preinflation”, n = 66), and after 90-second balloon coronary occlusion (“inflation”, n = 120). Performance of computer-measured ST-segment shift on vectorcardgiographic loops constructed from “abc” and 12 leads, standard 12-lead ECG, and consensus human interpretation in coronary occlusion detection were compared in “comparative” and “spot” modes (with/without reference to “baseline”) using areas under ROC curves (AUC), reliability, and sensitivity/specificity analysis.  Results Comparative “abc”-derived ST-segment shift was similar to two 12-lead methods (vector/traditional) in detecting balloon coronary occlusion (AUC = 0.95, 0.96, and 0.97, respectively, P = NS). Spot “abc” and 12-lead measurements (AUC = 0.72, 0.77, 0.68, respectively, P = NS) demonstrated poorer performance (P < 0.01 vs comparative measurements). Reliability analysis demonstrated comparative automated measurements in “good” agreement with reference (preinflation/inflation), while comparative human interpretation was in “moderate” range. Spot automated and human reading showed “poor” agreement.  Conclusions Vectorcardiographic ST-segment analysis using baseline comparison of 3-lead ECG system suitable for credit card-size personal device integration is similar to established 12-lead ECG methods in detecting balloon coronary occlusion.",
journal = "JACC: Advances",
title = "Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration",
volume = "2",
number = "6",
pages = "100454",
doi = "10.1016/j.jacadv.2023.100454"
}

Shvilkin, A., Vukajlović, D., Bojović, B. P., Hadžievski, L., Vajdic, B., Atanasoski, V., Miletić, M., Zimetbaum, P. J., Gibson, C. M.,& Vukčević, V.. (2023). Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration. in JACC: Advances, 2(6), 100454.
https://doi.org/10.1016/j.jacadv.2023.100454

Shvilkin A, Vukajlović D, Bojović BP, Hadžievski L, Vajdic B, Atanasoski V, Miletić M, Zimetbaum PJ, Gibson CM, Vukčević V. Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration. in JACC: Advances. 2023;2(6):100454.
doi:10.1016/j.jacadv.2023.100454 .

Shvilkin, Alexei, Vukajlović, Dejan, Bojović, Boško P., Hadžievski, Ljupčo, Vajdic, Branislav, Atanasoski, Vladimir, Miletić, Marjan, Zimetbaum, Peter J., Gibson, C. Michael, Vukčević, Vladan, "Coronary Artery Occlusion Detection Using 3-Lead ECG System Suitable for Credit Card-Size Personal Device Integration" in JACC: Advances, 2, no. 6 (2023):100454,
https://doi.org/10.1016/j.jacadv.2023.100454 . .

TY  - JOUR
AU  - Stojanović, Danka B.
AU  - Gligorić, Goran
AU  - Beličev, Petra
AU  - Belić, Milivoj R.
AU  - Hadžievski, Ljupčo
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9769
AB  - In this article, we propose a chiral metamaterial absorber based on four rotated twisted closed ring resonators operative in terahertz frequency range. The resonant features are analyzed by electric field amplitude distributions, and surface currents flow generated by the interaction of circularly polarized waves with the chiral structure. The highest field amplitudes at the fundamental resonance are obtained at the gap region of the resonator. Therefore, the efficiency of the proposed absorber is determined through response of absorption spectrum around this resonance with variation of geometrical parameters of the structure. Significant increase of absorption of the left circularly polarized light is obtained with variation of the period size of structure. Consequently, huge circular dichroism, and near-unity polarization selective absorption have been provided. This makes the proposed chiral structure a good candidate for designing circular polarization selective absorber. © 2020 IEEE.
T2  - IEEE Journal of Selected Topics in Quantum Electronics
T2  - IEEE Journal of Selected Topics in Quantum Electronics
T1  - Circular polarization selective metamaterial absorber in terahertz frequency range
VL  - 27
IS  - 1
DO  - 10.1109/JSTQE.2020.3024570
ER  - 

@article{
author = "Stojanović, Danka B. and Gligorić, Goran and Beličev, Petra and Belić, Milivoj R. and Hadžievski, Ljupčo",
year = "2021",
abstract = "In this article, we propose a chiral metamaterial absorber based on four rotated twisted closed ring resonators operative in terahertz frequency range. The resonant features are analyzed by electric field amplitude distributions, and surface currents flow generated by the interaction of circularly polarized waves with the chiral structure. The highest field amplitudes at the fundamental resonance are obtained at the gap region of the resonator. Therefore, the efficiency of the proposed absorber is determined through response of absorption spectrum around this resonance with variation of geometrical parameters of the structure. Significant increase of absorption of the left circularly polarized light is obtained with variation of the period size of structure. Consequently, huge circular dichroism, and near-unity polarization selective absorption have been provided. This makes the proposed chiral structure a good candidate for designing circular polarization selective absorber. © 2020 IEEE.",
journal = "IEEE Journal of Selected Topics in Quantum Electronics, IEEE Journal of Selected Topics in Quantum Electronics",
title = "Circular polarization selective metamaterial absorber in terahertz frequency range",
volume = "27",
number = "1",
doi = "10.1109/JSTQE.2020.3024570"
}

Stojanović, D. B., Gligorić, G., Beličev, P., Belić, M. R.,& Hadžievski, L.. (2021). Circular polarization selective metamaterial absorber in terahertz frequency range. in IEEE Journal of Selected Topics in Quantum Electronics, 27(1).
https://doi.org/10.1109/JSTQE.2020.3024570

Stojanović DB, Gligorić G, Beličev P, Belić MR, Hadžievski L. Circular polarization selective metamaterial absorber in terahertz frequency range. in IEEE Journal of Selected Topics in Quantum Electronics. 2021;27(1).
doi:10.1109/JSTQE.2020.3024570 .

Stojanović, Danka B., Gligorić, Goran, Beličev, Petra, Belić, Milivoj R., Hadžievski, Ljupčo, "Circular polarization selective metamaterial absorber in terahertz frequency range" in IEEE Journal of Selected Topics in Quantum Electronics, 27, no. 1 (2021),
https://doi.org/10.1109/JSTQE.2020.3024570 . .

TY  - JOUR
AU  - Benini, Sergio
AU  - Ivanović, Marija D.
AU  - Savardi, Mattia
AU  - Kršić, Jelena
AU  - Hadžievski, Ljupčo
AU  - Baronio, Fabio
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9547
AB  - The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 min of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation. © 2020
T2  - Data in Brief
T1  - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients
VL  - 34
SP  - 106635
DO  - 10.1016/j.dib.2020.106635
ER  - 

@article{
author = "Benini, Sergio and Ivanović, Marija D. and Savardi, Mattia and Kršić, Jelena and Hadžievski, Ljupčo and Baronio, Fabio",
year = "2021",
abstract = "The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 min of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation. © 2020",
journal = "Data in Brief",
title = "ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients",
volume = "34",
pages = "106635",
doi = "10.1016/j.dib.2020.106635"
}

Benini, S., Ivanović, M. D., Savardi, M., Kršić, J., Hadžievski, L.,& Baronio, F.. (2021). ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients. in Data in Brief, 34, 106635.
https://doi.org/10.1016/j.dib.2020.106635

Benini S, Ivanović MD, Savardi M, Kršić J, Hadžievski L, Baronio F. ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients. in Data in Brief. 2021;34:106635.
doi:10.1016/j.dib.2020.106635 .

Benini, Sergio, Ivanović, Marija D., Savardi, Mattia, Kršić, Jelena, Hadžievski, Ljupčo, Baronio, Fabio, "ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients" in Data in Brief, 34 (2021):106635,
https://doi.org/10.1016/j.dib.2020.106635 . .

TY  - JOUR
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Maluckov, Aleksandra
AU  - Hadžievski, Ljupčo
AU  - Turitsyn, Sergei
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9869
AB  - Topological properties can make light field remarkably robust to various external perturbations. The ability to control and change on demand topological characteristics of light paves the way to new interesting physical phenomena and applications. Here, numerical modelling design of the device based on active multi-core fiber that can change topological charge of the state of light has been proposed. The concept is based on the nonlinear dynamics of optical vortices in active multi-core optical fiber with linearly coupled cores, saturated gain, and constant linear losses. Results demonstrate that the proposed system can provide change of the topological charge of vortices.
T2  - Annalen der Physik
T1  - Topological charge switch in active multi-core fibers
VL  - 533
IS  - 9
SP  - 2100108
DO  - 10.1002/andp.202100108
ER  - 

@article{
author = "Beličev, Petra and Gligorić, Goran and Maluckov, Aleksandra and Hadžievski, Ljupčo and Turitsyn, Sergei",
year = "2021",
abstract = "Topological properties can make light field remarkably robust to various external perturbations. The ability to control and change on demand topological characteristics of light paves the way to new interesting physical phenomena and applications. Here, numerical modelling design of the device based on active multi-core fiber that can change topological charge of the state of light has been proposed. The concept is based on the nonlinear dynamics of optical vortices in active multi-core optical fiber with linearly coupled cores, saturated gain, and constant linear losses. Results demonstrate that the proposed system can provide change of the topological charge of vortices.",
journal = "Annalen der Physik",
title = "Topological charge switch in active multi-core fibers",
volume = "533",
number = "9",
pages = "2100108",
doi = "10.1002/andp.202100108"
}

Beličev, P., Gligorić, G., Maluckov, A., Hadžievski, L.,& Turitsyn, S.. (2021). Topological charge switch in active multi-core fibers. in Annalen der Physik, 533(9), 2100108.
https://doi.org/10.1002/andp.202100108

Beličev P, Gligorić G, Maluckov A, Hadžievski L, Turitsyn S. Topological charge switch in active multi-core fibers. in Annalen der Physik. 2021;533(9):2100108.
doi:10.1002/andp.202100108 .

Beličev, Petra, Gligorić, Goran, Maluckov, Aleksandra, Hadžievski, Ljupčo, Turitsyn, Sergei, "Topological charge switch in active multi-core fibers" in Annalen der Physik, 533, no. 9 (2021):2100108,
https://doi.org/10.1002/andp.202100108 . .

TY  - JOUR
AU  - Pryamikov, Andrey
AU  - Hadžievski, Ljupčo
AU  - Fedoruk, Mikhail
AU  - Turitsyn, Sergei
AU  - Aceves, Alejandro
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10033
AB  - Coherent vortex structures are fascinating physical objects that are widespread in nature: from large scale atmospheric phenomena, such as tornadoes and the Great Red Spot of Jupiter to microscopic size topological defects in quantum physics and optics. Unlike classical vortex dynamics in fluids, optical vortices feature new interesting properties. For instance, novel discrete optical vortices can be generated in photonic lattices, leading to new physics. In nonlinear optical media, vortices can be treated as solitons with nontrivial characteristics currently studied under the emerging field of topological photonics. Parallel to theoretical advances, new areas of the engineering applications based on light vortices have emerged. Examples include the possibility of carrying information coded in the vortex orbital angular momentum, understood as a spatial-division-multiplexing scheme, to the creation of optical tweezers for efficient manipulation of small objects. This report presents an overview highlighting some of the recent advances in the field of optical vortices with special attention on discrete vortex systems and related numerical methods for modeling propagation in multi-core fibers.
T2  - Journal of the European Optical Society-Rapid Publications
T1  - Optical vortices in waveguides with discrete and continuous rotational symmetry
VL  - 17
IS  - 1
SP  - 23
DO  - 10.1186/s41476-021-00168-5
ER  - 

@article{
author = "Pryamikov, Andrey and Hadžievski, Ljupčo and Fedoruk, Mikhail and Turitsyn, Sergei and Aceves, Alejandro",
year = "2021",
abstract = "Coherent vortex structures are fascinating physical objects that are widespread in nature: from large scale atmospheric phenomena, such as tornadoes and the Great Red Spot of Jupiter to microscopic size topological defects in quantum physics and optics. Unlike classical vortex dynamics in fluids, optical vortices feature new interesting properties. For instance, novel discrete optical vortices can be generated in photonic lattices, leading to new physics. In nonlinear optical media, vortices can be treated as solitons with nontrivial characteristics currently studied under the emerging field of topological photonics. Parallel to theoretical advances, new areas of the engineering applications based on light vortices have emerged. Examples include the possibility of carrying information coded in the vortex orbital angular momentum, understood as a spatial-division-multiplexing scheme, to the creation of optical tweezers for efficient manipulation of small objects. This report presents an overview highlighting some of the recent advances in the field of optical vortices with special attention on discrete vortex systems and related numerical methods for modeling propagation in multi-core fibers.",
journal = "Journal of the European Optical Society-Rapid Publications",
title = "Optical vortices in waveguides with discrete and continuous rotational symmetry",
volume = "17",
number = "1",
pages = "23",
doi = "10.1186/s41476-021-00168-5"
}

Pryamikov, A., Hadžievski, L., Fedoruk, M., Turitsyn, S.,& Aceves, A.. (2021). Optical vortices in waveguides with discrete and continuous rotational symmetry. in Journal of the European Optical Society-Rapid Publications, 17(1), 23.
https://doi.org/10.1186/s41476-021-00168-5

Pryamikov A, Hadžievski L, Fedoruk M, Turitsyn S, Aceves A. Optical vortices in waveguides with discrete and continuous rotational symmetry. in Journal of the European Optical Society-Rapid Publications. 2021;17(1):23.
doi:10.1186/s41476-021-00168-5 .

Pryamikov, Andrey, Hadžievski, Ljupčo, Fedoruk, Mikhail, Turitsyn, Sergei, Aceves, Alejandro, "Optical vortices in waveguides with discrete and continuous rotational symmetry" in Journal of the European Optical Society-Rapid Publications, 17, no. 1 (2021):23,
https://doi.org/10.1186/s41476-021-00168-5 . .

TY  - CONF
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Maluckov, Aleksandra
AU  - Hadžievski, Ljupčo
AU  - Turitsyn, S.
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10901
AB  - The multi-core fiber (MCF) is a physical system of high practical importance. In addition to standard exploitation, the MCFs may support discrete vortices that carry orbital angular momentum suitable for spatial-division-multiplexing in high capacity fiber-optic communication systems which may also be attractive for applications in high power lasers. Up to now, the main concern of our study has been related to optimization of the conditions capable to ensure transfer of high coherent light through the MCFs [1]. Regarding this we firstly proved the possibility of nonlinearity managed propagation of highly coherent vortices carrying huge power through the passive circular MCFs, which consist of small number of periphery cores. The central core has been shown to play the role of optional switch/gate of coherent light transfer [1]. In addition, the effects of the presence of central core and material loss/gain of all cores on the linear MCF system eigenvalue commensurability conditions have shown significant impact on the coherent planar and vortex mode dynamics [2]. All these findings stimulated the investigation of possibility to amplify the power transferred through the MCF via vortex carriers by inducing effects of the saturable gain and non-saturable loss in the periphery and/or central cores [3]. We numerically consider three cases of active circular MCFs. In the first case active were only periphery cores. Secondly, we investigated response of the system with only central core active, while the last case included all cores to be active. The light propagation is modeled by the generalized nonlinear difference-differential Schrödinger equations with complex coefficients and saturable gain [3]. Results for MCF with 4, 5 and 6 periphery cores have shown that the active periphery is the most promising candidate for topological charge switch of vortices carrying high powers [4]. In this specific operating regime, MCF provides change of the vortex topological charge value, i.e. transition between different vortex states. Moreover, presented system supports topological charge switch function between noncounterpart vortices by proper tailoring the ratio between gain and loss in periphery. The key condition for this phenomenon is existence of the central core which appears to play role of mode dynamics moderator. Being the ‘singular phase’ point of vortex, the central core which only passively takes part in tunneling energy towards the periphery cores, can support the coherent light amplification through the MCF. On the top of this, presented system shows to be a promising platform for practical realization of devices covering range of multiple functions in applications: from high-power fiber lasers to coherent beam combiners and selective carriers of vortex beams.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade
T1  - Active multi-core fibers – photonic platform for development of a topological charge switching device
SP  - 71
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10901
ER  - 

@conference{
author = "Beličev, Petra and Gligorić, Goran and Maluckov, Aleksandra and Hadžievski, Ljupčo and Turitsyn, S.",
year = "2021",
abstract = "The multi-core fiber (MCF) is a physical system of high practical importance. In addition to standard exploitation, the MCFs may support discrete vortices that carry orbital angular momentum suitable for spatial-division-multiplexing in high capacity fiber-optic communication systems which may also be attractive for applications in high power lasers. Up to now, the main concern of our study has been related to optimization of the conditions capable to ensure transfer of high coherent light through the MCFs [1]. Regarding this we firstly proved the possibility of nonlinearity managed propagation of highly coherent vortices carrying huge power through the passive circular MCFs, which consist of small number of periphery cores. The central core has been shown to play the role of optional switch/gate of coherent light transfer [1]. In addition, the effects of the presence of central core and material loss/gain of all cores on the linear MCF system eigenvalue commensurability conditions have shown significant impact on the coherent planar and vortex mode dynamics [2]. All these findings stimulated the investigation of possibility to amplify the power transferred through the MCF via vortex carriers by inducing effects of the saturable gain and non-saturable loss in the periphery and/or central cores [3]. We numerically consider three cases of active circular MCFs. In the first case active were only periphery cores. Secondly, we investigated response of the system with only central core active, while the last case included all cores to be active. The light propagation is modeled by the generalized nonlinear difference-differential Schrödinger equations with complex coefficients and saturable gain [3]. Results for MCF with 4, 5 and 6 periphery cores have shown that the active periphery is the most promising candidate for topological charge switch of vortices carrying high powers [4]. In this specific operating regime, MCF provides change of the vortex topological charge value, i.e. transition between different vortex states. Moreover, presented system supports topological charge switch function between noncounterpart vortices by proper tailoring the ratio between gain and loss in periphery. The key condition for this phenomenon is existence of the central core which appears to play role of mode dynamics moderator. Being the ‘singular phase’ point of vortex, the central core which only passively takes part in tunneling energy towards the periphery cores, can support the coherent light amplification through the MCF. On the top of this, presented system shows to be a promising platform for practical realization of devices covering range of multiple functions in applications: from high-power fiber lasers to coherent beam combiners and selective carriers of vortex beams.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade",
title = "Active multi-core fibers – photonic platform for development of a topological charge switching device",
pages = "71",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10901"
}

Beličev, P., Gligorić, G., Maluckov, A., Hadžievski, L.,& Turitsyn, S.. (2021). Active multi-core fibers – photonic platform for development of a topological charge switching device. in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade
Belgrade : Institute of Physics Belgrade., 71.
https://hdl.handle.net/21.15107/rcub_vinar_10901

Beličev P, Gligorić G, Maluckov A, Hadžievski L, Turitsyn S. Active multi-core fibers – photonic platform for development of a topological charge switching device. in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade. 2021;:71.
https://hdl.handle.net/21.15107/rcub_vinar_10901 .

Beličev, Petra, Gligorić, Goran, Maluckov, Aleksandra, Hadžievski, Ljupčo, Turitsyn, S., "Active multi-core fibers – photonic platform for development of a topological charge switching device" in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade (2021):71,
https://hdl.handle.net/21.15107/rcub_vinar_10901 .

TY  - CONF
AU  - Stojanović, D. B.
AU  - Milošević, V.
AU  - Ralević, Uroš
AU  - Hadžievski, Ljupčo
PY  - 2021
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10915
AB  - Controlling states of circular polarization with metamaterials [1] enables diverse applications in information processing, spectroscopy and communications. Furthermore, strong modulation of polarization of terahertz (THz) electromagnetic waves can be achieved by integrating active material (such as graphene) with metamaterials [2,3]. The chiral effects can be tuned and metamaterial sensing capabilities can be improved by dynamical modulation of the graphene conductivity. Nowadays, there is a need for rapid and reliable detection of biological samples, especially viruses. The advantage of active metamaterials is precise distinction in between viruses, which is challenging due to their nearly comparable refractive indices. This makes them appropriate for biosensor applications [4,5]. In this work, we numerically investigate THz electromagnetic wave propagation through metamaterial composed of resonant elements based on metallic strips embedded with gated graphene layer. The analysis is provided by calculation of cross- and co-reflection coefficients and efficiency of linear to circular polarization conversion with the change of the Fermi energy of graphene. In addition, the sensitivity of reflection spectra is tested for variations of refractive index, using the data available in the literature for several types of viruses, which is indicative for performance of the proposed metamaterial as a potential biosensor. We expect that proposed structure will enable easier biosensor fabrication with enhanced detection sensitivity compared to previously numerically investigated structures.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade
T1  - Active terahertz metamaterial for polarization manipulation and biosensing
SP  - 159
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10915
ER  - 

@conference{
author = "Stojanović, D. B. and Milošević, V. and Ralević, Uroš and Hadžievski, Ljupčo",
year = "2021",
abstract = "Controlling states of circular polarization with metamaterials [1] enables diverse applications in information processing, spectroscopy and communications. Furthermore, strong modulation of polarization of terahertz (THz) electromagnetic waves can be achieved by integrating active material (such as graphene) with metamaterials [2,3]. The chiral effects can be tuned and metamaterial sensing capabilities can be improved by dynamical modulation of the graphene conductivity. Nowadays, there is a need for rapid and reliable detection of biological samples, especially viruses. The advantage of active metamaterials is precise distinction in between viruses, which is challenging due to their nearly comparable refractive indices. This makes them appropriate for biosensor applications [4,5]. In this work, we numerically investigate THz electromagnetic wave propagation through metamaterial composed of resonant elements based on metallic strips embedded with gated graphene layer. The analysis is provided by calculation of cross- and co-reflection coefficients and efficiency of linear to circular polarization conversion with the change of the Fermi energy of graphene. In addition, the sensitivity of reflection spectra is tested for variations of refractive index, using the data available in the literature for several types of viruses, which is indicative for performance of the proposed metamaterial as a potential biosensor. We expect that proposed structure will enable easier biosensor fabrication with enhanced detection sensitivity compared to previously numerically investigated structures.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade",
title = "Active terahertz metamaterial for polarization manipulation and biosensing",
pages = "159",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10915"
}

Stojanović, D. B., Milošević, V., Ralević, U.,& Hadžievski, L.. (2021). Active terahertz metamaterial for polarization manipulation and biosensing. in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade
Belgrade : Institute of Physics Belgrade., 159.
https://hdl.handle.net/21.15107/rcub_vinar_10915

Stojanović DB, Milošević V, Ralević U, Hadžievski L. Active terahertz metamaterial for polarization manipulation and biosensing. in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade. 2021;:159.
https://hdl.handle.net/21.15107/rcub_vinar_10915 .

Stojanović, D. B., Milošević, V., Ralević, Uroš, Hadžievski, Ljupčo, "Active terahertz metamaterial for polarization manipulation and biosensing" in PHOTONICA2021 : 8th International School and Conference on Photonics and HEMMAGINERO workshop : Abstracts of Tutorial, Keynote, Invited Lectures, Progress Reports and Contributed Papers; August 23-27, 2021; Belgrade (2021):159,
https://hdl.handle.net/21.15107/rcub_vinar_10915 .

TY  - JOUR
AU  - Popović Maneski, Lana
AU  - Ivanović, Marija D.
AU  - Atanasoski, Vladimir
AU  - Miletić, Marjan
AU  - Zdolšek, Sanja
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8940
AB  - Wearable smart monitors (WSMs) applied for the estimation of electrophysiological signals are of utmost interest for a non-stressed life. WSM which records heart muscle activities could signalize timely a life-threatening event. The heart muscle activities are typically recorded across the heart at the surface of the body; hence, a WSM monitor requires high-quality surface electrodes. The electrodes used in the clinical settings [i.e. silver/silver chloride (Ag/AgCl) with the gel] are not practical for the daily out of clinic usage. A practical WSM requires the application of a dry electrode with stable and reproducible electrical characteristics. We compared the characteristics of six types of dry electrodes and one gelled electrode during short-term recordings sessions (≈30 s) in real-life conditions: Orbital, monolithic polymer plated with Ag/AgCl, and five rectangular shaped 10 × 6 × 2 mm electrodes (Orbital, Ag electrode, Ag/AgCl electrode, gold electrode and stainless-steel AISI304). The results of a well-controlled analysis which considered motion artifacts, line noise and junction potentials suggest that among the dry electrodes Ag/AgCl performs the best. The Ag/AgCl electrode is in average three times better compared with the stainless-steel electrode often used in WSMs.
T2  - Biomedical Engineering / Biomedizinische Technik
T1  - Properties of different types of dry electrodes for wearable smart monitoring devices
VL  - 65
IS  - 4
SP  - 405
EP  - 415
DO  - 10.1515/bmt-2019-0167
ER  - 

@article{
author = "Popović Maneski, Lana and Ivanović, Marija D. and Atanasoski, Vladimir and Miletić, Marjan and Zdolšek, Sanja and Bojović, Boško and Hadžievski, Ljupčo",
year = "2020",
abstract = "Wearable smart monitors (WSMs) applied for the estimation of electrophysiological signals are of utmost interest for a non-stressed life. WSM which records heart muscle activities could signalize timely a life-threatening event. The heart muscle activities are typically recorded across the heart at the surface of the body; hence, a WSM monitor requires high-quality surface electrodes. The electrodes used in the clinical settings [i.e. silver/silver chloride (Ag/AgCl) with the gel] are not practical for the daily out of clinic usage. A practical WSM requires the application of a dry electrode with stable and reproducible electrical characteristics. We compared the characteristics of six types of dry electrodes and one gelled electrode during short-term recordings sessions (≈30 s) in real-life conditions: Orbital, monolithic polymer plated with Ag/AgCl, and five rectangular shaped 10 × 6 × 2 mm electrodes (Orbital, Ag electrode, Ag/AgCl electrode, gold electrode and stainless-steel AISI304). The results of a well-controlled analysis which considered motion artifacts, line noise and junction potentials suggest that among the dry electrodes Ag/AgCl performs the best. The Ag/AgCl electrode is in average three times better compared with the stainless-steel electrode often used in WSMs.",
journal = "Biomedical Engineering / Biomedizinische Technik",
title = "Properties of different types of dry electrodes for wearable smart monitoring devices",
volume = "65",
number = "4",
pages = "405-415",
doi = "10.1515/bmt-2019-0167"
}

Popović Maneski, L., Ivanović, M. D., Atanasoski, V., Miletić, M., Zdolšek, S., Bojović, B.,& Hadžievski, L.. (2020). Properties of different types of dry electrodes for wearable smart monitoring devices. in Biomedical Engineering / Biomedizinische Technik, 65(4), 405-415.
https://doi.org/10.1515/bmt-2019-0167

Popović Maneski L, Ivanović MD, Atanasoski V, Miletić M, Zdolšek S, Bojović B, Hadžievski L. Properties of different types of dry electrodes for wearable smart monitoring devices. in Biomedical Engineering / Biomedizinische Technik. 2020;65(4):405-415.
doi:10.1515/bmt-2019-0167 .

Popović Maneski, Lana, Ivanović, Marija D., Atanasoski, Vladimir, Miletić, Marjan, Zdolšek, Sanja, Bojović, Boško, Hadžievski, Ljupčo, "Properties of different types of dry electrodes for wearable smart monitoring devices" in Biomedical Engineering / Biomedizinische Technik, 65, no. 4 (2020):405-415,
https://doi.org/10.1515/bmt-2019-0167 . .

TY  - JOUR
AU  - Ivanović, Marija D.
AU  - Mančić, Ana
AU  - Hermann-Avigliano, Carla
AU  - Hadžievski, Ljupčo
AU  - Maluckov, Aleksandra
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8837
AB  - In this paper, we establish a new scheme for identification and classification of high intensity events generated by the propagation of light through a photorefractive SBN crystal. Among these events, which are the inevitable consequence of the development of modulation instability, are speckling and soliton-like patterns. The usual classifiers, developed on statistical measures, such as the significant intensity, often provide only a partial characterization of these events. Here, we try to overcome this deficiency by implementing the convolution neural network method to relate experimental data of light intensity distribution and corresponding numerical outputs with different high intensity regimes. The train and test sets are formed of experimentally obtained intensity profiles at the crystal output facet and corresponding numerical profiles. The accuracy of detection of speckles reaches maximum value of 100%, while the accuracy of solitons and caustic detection is above 97%. These performances are promising for the creation of neural network based routines for prediction of extreme events in wave media. © 2020 IOP Publishing Ltd.
T2  - Journal of Optics
T1  - Deep learning-based classification of high intensity light patterns in photorefractive crystals
VL  - 22
IS  - 3
SP  - 035504
DO  - 10.1088/2040-8986/ab70f0
ER  - 

@article{
author = "Ivanović, Marija D. and Mančić, Ana and Hermann-Avigliano, Carla and Hadžievski, Ljupčo and Maluckov, Aleksandra",
year = "2020",
abstract = "In this paper, we establish a new scheme for identification and classification of high intensity events generated by the propagation of light through a photorefractive SBN crystal. Among these events, which are the inevitable consequence of the development of modulation instability, are speckling and soliton-like patterns. The usual classifiers, developed on statistical measures, such as the significant intensity, often provide only a partial characterization of these events. Here, we try to overcome this deficiency by implementing the convolution neural network method to relate experimental data of light intensity distribution and corresponding numerical outputs with different high intensity regimes. The train and test sets are formed of experimentally obtained intensity profiles at the crystal output facet and corresponding numerical profiles. The accuracy of detection of speckles reaches maximum value of 100%, while the accuracy of solitons and caustic detection is above 97%. These performances are promising for the creation of neural network based routines for prediction of extreme events in wave media. © 2020 IOP Publishing Ltd.",
journal = "Journal of Optics",
title = "Deep learning-based classification of high intensity light patterns in photorefractive crystals",
volume = "22",
number = "3",
pages = "035504",
doi = "10.1088/2040-8986/ab70f0"
}

Ivanović, M. D., Mančić, A., Hermann-Avigliano, C., Hadžievski, L.,& Maluckov, A.. (2020). Deep learning-based classification of high intensity light patterns in photorefractive crystals. in Journal of Optics, 22(3), 035504.
https://doi.org/10.1088/2040-8986/ab70f0

Ivanović MD, Mančić A, Hermann-Avigliano C, Hadžievski L, Maluckov A. Deep learning-based classification of high intensity light patterns in photorefractive crystals. in Journal of Optics. 2020;22(3):035504.
doi:10.1088/2040-8986/ab70f0 .

Ivanović, Marija D., Mančić, Ana, Hermann-Avigliano, Carla, Hadžievski, Ljupčo, Maluckov, Aleksandra, "Deep learning-based classification of high intensity light patterns in photorefractive crystals" in Journal of Optics, 22, no. 3 (2020):035504,
https://doi.org/10.1088/2040-8986/ab70f0 . .

TY  - DATA
AU  - Benini, Sergio
AU  - Ivanović, Marija D.
AU  - Savardi, Mattia
AU  - Kršić, Jelena
AU  - Hadžievski, Ljupčo
AU  - Baronio, Fabio
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9549
AB  - The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 minute of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation.
T2  - Mendeley Data
T1  - Cardially - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients
DO  - 10.17632/wpr5nzyn2z.1
ER  - 

@misc{
author = "Benini, Sergio and Ivanović, Marija D. and Savardi, Mattia and Kršić, Jelena and Hadžievski, Ljupčo and Baronio, Fabio",
year = "2020",
abstract = "The provided database of 260 ECG signals was collected from patients with out-of-hospital cardiac arrest while treated by the emergency medical services. Each ECG signal contains a 9 second waveform showing ventricular fibrillation, followed by 1 minute of post-shock waveform. Patients’ ECGs are made available in multiple formats. All ECGs recorded during the prehospital treatment are provided in PFD files, after being anonymized, printed in paper, and scanned. For each ECG, the dataset also includes the whole digitized waveform (9 s pre- and 1 min post-shock each) and numerous features in temporal and frequency domain extracted from the 9 s episode immediately prior to the first defibrillation shock. Based on the shock outcome, each ECG file has been annotated by three expert cardiologists, - using majority decision -, as successful (56 cases), unsuccessful (195 cases), or indeterminable (9 cases). The code for preprocessing, for feature extraction, and for limiting the investigation to different temporal intervals before the shock is also provided. These data could be reused to design algorithms to predict shock outcome based on ventricular fibrillation analysis, with the goal to optimize the defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation and/or drug administration) for enhancing resuscitation.",
journal = "Mendeley Data",
title = "Cardially - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients",
doi = "10.17632/wpr5nzyn2z.1"
}

Benini, S., Ivanović, M. D., Savardi, M., Kršić, J., Hadžievski, L.,& Baronio, F.. (2020). Cardially - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients. in Mendeley Data.
https://doi.org/10.17632/wpr5nzyn2z.1

Benini S, Ivanović MD, Savardi M, Kršić J, Hadžievski L, Baronio F. Cardially - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients. in Mendeley Data. 2020;.
doi:10.17632/wpr5nzyn2z.1 .

Benini, Sergio, Ivanović, Marija D., Savardi, Mattia, Kršić, Jelena, Hadžievski, Ljupčo, Baronio, Fabio, "Cardially - ECG waveform dataset for predicting defibrillation outcome in out-of-hospital cardiac arrested patients" in Mendeley Data (2020),
https://doi.org/10.17632/wpr5nzyn2z.1 . .

TY  - JOUR
AU  - Ivanović, Marija D.
AU  - Hannink, Julius
AU  - Ring, Matthias
AU  - Baronio, Fabio
AU  - Vukčević, Vladan
AU  - Hadžievski, Ljupčo
AU  - Eskofier, Bjoern
PY  - 2020
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/9678
AB  - Optimizing timing of defibrillation by evaluating the likelihood of a successful outcome could significantly enhance resuscitation. Previous studies employed conventional machine learning approaches and hand-crafted features to address this issue, but none have achieved superior performance to be widely accepted. This study proposes a novel approach in which predictive features are automatically learned.MethodsA raw 4s VF episode immediately prior to first defibrillation shock was feed to a 3-stage CNN feature extractor. Each stage was composed of 4 components: convolution, rectified linear unit activation, dropout and max-pooling. At the end of feature extractor, the feature map was flattened and connected to a fully connected multi-layer perceptron for classification. For model evaluation, a 10 fold cross-validation was employed. To balance classes, SMOTE oversampling method has been applied to minority class.ResultsThe obtained results show that the proposed model is highly accurate in predicting defibrillation outcome (Acc = 93.6 %). Since recommendations on classifiers suggest at least 50 % specificity and 95 % sensitivity as safe and useful predictors for defibrillation decision, the reported sensitivity of 98.8 % and specificity of 88.2 %, with the analysis speed of 3 ms/input signal, indicate that the proposed model possesses a good prospective to be implemented in automated external defibrillators.ConclusionsThe learned features demonstrate superiority over hand-crafted ones when performed on the same dataset. This approach benefits from being fully automatic by fusing feature extraction, selection and classification into a single learning model. It provides a superior strategy that can be used as a tool to guide treatment of OHCA patients in bringing optimal decision of precedence treatment. Furthermore, for encouraging replicability, the dataset has been made publicly available to the research community.
T2  - Artificial Intelligence in Medicine
T1  - Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design
VL  - 110
SP  - 101963
DO  - 10.1016/j.artmed.2020.101963
ER  - 

@article{
author = "Ivanović, Marija D. and Hannink, Julius and Ring, Matthias and Baronio, Fabio and Vukčević, Vladan and Hadžievski, Ljupčo and Eskofier, Bjoern",
year = "2020",
abstract = "Optimizing timing of defibrillation by evaluating the likelihood of a successful outcome could significantly enhance resuscitation. Previous studies employed conventional machine learning approaches and hand-crafted features to address this issue, but none have achieved superior performance to be widely accepted. This study proposes a novel approach in which predictive features are automatically learned.MethodsA raw 4s VF episode immediately prior to first defibrillation shock was feed to a 3-stage CNN feature extractor. Each stage was composed of 4 components: convolution, rectified linear unit activation, dropout and max-pooling. At the end of feature extractor, the feature map was flattened and connected to a fully connected multi-layer perceptron for classification. For model evaluation, a 10 fold cross-validation was employed. To balance classes, SMOTE oversampling method has been applied to minority class.ResultsThe obtained results show that the proposed model is highly accurate in predicting defibrillation outcome (Acc = 93.6 %). Since recommendations on classifiers suggest at least 50 % specificity and 95 % sensitivity as safe and useful predictors for defibrillation decision, the reported sensitivity of 98.8 % and specificity of 88.2 %, with the analysis speed of 3 ms/input signal, indicate that the proposed model possesses a good prospective to be implemented in automated external defibrillators.ConclusionsThe learned features demonstrate superiority over hand-crafted ones when performed on the same dataset. This approach benefits from being fully automatic by fusing feature extraction, selection and classification into a single learning model. It provides a superior strategy that can be used as a tool to guide treatment of OHCA patients in bringing optimal decision of precedence treatment. Furthermore, for encouraging replicability, the dataset has been made publicly available to the research community.",
journal = "Artificial Intelligence in Medicine",
title = "Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design",
volume = "110",
pages = "101963",
doi = "10.1016/j.artmed.2020.101963"
}

Ivanović, M. D., Hannink, J., Ring, M., Baronio, F., Vukčević, V., Hadžievski, L.,& Eskofier, B.. (2020). Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design. in Artificial Intelligence in Medicine, 110, 101963.
https://doi.org/10.1016/j.artmed.2020.101963

Ivanović MD, Hannink J, Ring M, Baronio F, Vukčević V, Hadžievski L, Eskofier B. Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design. in Artificial Intelligence in Medicine. 2020;110:101963.
doi:10.1016/j.artmed.2020.101963 .

Ivanović, Marija D., Hannink, Julius, Ring, Matthias, Baronio, Fabio, Vukčević, Vladan, Hadžievski, Ljupčo, Eskofier, Bjoern, "Predicting defibrillation success in out-of-hospital cardiac arrested patients: Moving beyond feature design" in Artificial Intelligence in Medicine, 110 (2020):101963,
https://doi.org/10.1016/j.artmed.2020.101963 . .

TY  - CONF
AU  - Ivanović, Marija D.
AU  - Atanasoski, Vladimir
AU  - Shvilkin, Alexei
AU  - Hadžievski, Ljupčo
AU  - Maluckov, Aleksandra
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8805
AB  - Atrial fibrillation (AF) and atrial flutter (AFL) represent atrial arrhythmias closely related to increasing risk for embolic stroke, and therefore being in the focus of cardiologists. While the reported methods for AF detection exhibit high performances, little attention has been given to distinguishing these two arrhythmias. In this study, we propose a deep neural network architecture, which combines convolutional and recurrent neural networks, for extracting features from sequence of RR intervals. The learned features were used to classify a long term ECG signals as AF, AFL or sinus rhythm (SR). A 10-fold cross-validation strategy was used for choosing an architecture design and tuning model hyperparameters. Accuracy of 88.28 %, with the sensitivities of 93.83%, 83.60% and 83.83% for SR, AF and AFL, respectively, was achieved. After choosing optimal network structure, the model was trained on the entire training set and finally evaluated on the blindfold test set which resulted in 89.67% accuracy, and 97.20%, 94.20%, and 77.78% sensitivity for SR, AF and AFL, respectively. Promising performances of the proposed model encourage continuing development of highly specific AF and AFL detection procedure based on deep learning. Distinction between these two arrhythmias can make therapy more efficient and decrease the recovery time to normal heart rhythm. © 2019 IEEE.
PB  - IEEE
C3  - Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (41; 2019; Berlin)
T1  - Deep Learning Approach for Highly Specific Atrial Fibrillation and Flutter Detection based on RR Intervals
SP  - 1780
EP  - 1783
DO  - 10.1109/EMBC.2019.8856806
ER  - 

@conference{
author = "Ivanović, Marija D. and Atanasoski, Vladimir and Shvilkin, Alexei and Hadžievski, Ljupčo and Maluckov, Aleksandra",
year = "2019",
abstract = "Atrial fibrillation (AF) and atrial flutter (AFL) represent atrial arrhythmias closely related to increasing risk for embolic stroke, and therefore being in the focus of cardiologists. While the reported methods for AF detection exhibit high performances, little attention has been given to distinguishing these two arrhythmias. In this study, we propose a deep neural network architecture, which combines convolutional and recurrent neural networks, for extracting features from sequence of RR intervals. The learned features were used to classify a long term ECG signals as AF, AFL or sinus rhythm (SR). A 10-fold cross-validation strategy was used for choosing an architecture design and tuning model hyperparameters. Accuracy of 88.28 %, with the sensitivities of 93.83%, 83.60% and 83.83% for SR, AF and AFL, respectively, was achieved. After choosing optimal network structure, the model was trained on the entire training set and finally evaluated on the blindfold test set which resulted in 89.67% accuracy, and 97.20%, 94.20%, and 77.78% sensitivity for SR, AF and AFL, respectively. Promising performances of the proposed model encourage continuing development of highly specific AF and AFL detection procedure based on deep learning. Distinction between these two arrhythmias can make therapy more efficient and decrease the recovery time to normal heart rhythm. © 2019 IEEE.",
publisher = "IEEE",
journal = "Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (41; 2019; Berlin)",
title = "Deep Learning Approach for Highly Specific Atrial Fibrillation and Flutter Detection based on RR Intervals",
pages = "1780-1783",
doi = "10.1109/EMBC.2019.8856806"
}

Ivanović, M. D., Atanasoski, V., Shvilkin, A., Hadžievski, L.,& Maluckov, A.. (2019). Deep Learning Approach for Highly Specific Atrial Fibrillation and Flutter Detection based on RR Intervals. in Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (41; 2019; Berlin)
IEEE., 1780-1783.
https://doi.org/10.1109/EMBC.2019.8856806

Ivanović MD, Atanasoski V, Shvilkin A, Hadžievski L, Maluckov A. Deep Learning Approach for Highly Specific Atrial Fibrillation and Flutter Detection based on RR Intervals. in Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (41; 2019; Berlin). 2019;:1780-1783.
doi:10.1109/EMBC.2019.8856806 .

Ivanović, Marija D., Atanasoski, Vladimir, Shvilkin, Alexei, Hadžievski, Ljupčo, Maluckov, Aleksandra, "Deep Learning Approach for Highly Specific Atrial Fibrillation and Flutter Detection based on RR Intervals" in Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) (41; 2019; Berlin) (2019):1780-1783,
https://doi.org/10.1109/EMBC.2019.8856806 . .

TY  - CONF
AU  - Lazović, Aleksandar
AU  - Popović Maneski, Lana
AU  - Hadžievski, Ljupčo
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/10876
AB  - To research the possibility of noninvasive detection of heart failure we developed an acquisition system with multiple sensors. The system synchronously measures cardiovascular pulsations, heart sounds and ECG using different types of sensors positioned only on the patient’s body. The system has a modular structure with five modules: 1. Module for controlling the light source (MWLS) 2. Module for data acquisition from fiber optical sensors (FBGA) with the compact optical spectral analyzer 3. Module for the acquisition of hearth sounds (PCG) with four ports for microphones; 4. Module for the acquisition of standard ECG signals; 5. Module for data acquisition from three accelerometers and three photoplethysmography sensors (ACC/PPG).
PB  - Belgrade : ETRAN
PB  - Belgrade : Academic Mind
C3  - Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine
T1  - Multi-sensor acquisition system for noninvasive detection of heart failure
SP  - 235
EP  - 238
UR  - https://hdl.handle.net/21.15107/rcub_vinar_10876
ER  - 

@conference{
author = "Lazović, Aleksandar and Popović Maneski, Lana and Hadžievski, Ljupčo",
year = "2019",
abstract = "To research the possibility of noninvasive detection of heart failure we developed an acquisition system with multiple sensors. The system synchronously measures cardiovascular pulsations, heart sounds and ECG using different types of sensors positioned only on the patient’s body. The system has a modular structure with five modules: 1. Module for controlling the light source (MWLS) 2. Module for data acquisition from fiber optical sensors (FBGA) with the compact optical spectral analyzer 3. Module for the acquisition of hearth sounds (PCG) with four ports for microphones; 4. Module for the acquisition of standard ECG signals; 5. Module for data acquisition from three accelerometers and three photoplethysmography sensors (ACC/PPG).",
publisher = "Belgrade : ETRAN, Belgrade : Academic Mind",
journal = "Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine",
title = "Multi-sensor acquisition system for noninvasive detection of heart failure",
pages = "235-238",
url = "https://hdl.handle.net/21.15107/rcub_vinar_10876"
}

Lazović, A., Popović Maneski, L.,& Hadžievski, L.. (2019). Multi-sensor acquisition system for noninvasive detection of heart failure. in Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine
Belgrade : ETRAN., 235-238.
https://hdl.handle.net/21.15107/rcub_vinar_10876

Lazović A, Popović Maneski L, Hadžievski L. Multi-sensor acquisition system for noninvasive detection of heart failure. in Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine. 2019;:235-238.
https://hdl.handle.net/21.15107/rcub_vinar_10876 .

Lazović, Aleksandar, Popović Maneski, Lana, Hadžievski, Ljupčo, "Multi-sensor acquisition system for noninvasive detection of heart failure" in Proceedings of Papers – 6th International Conference on Electrical, Electronic and Computing Engineering, IcETRAN 2019, Silver Lake, Serbia, June 03 – 06, 2019 / Zbornik radova - 63. Konferencija za elektroniku, telekomunikacije, računarstvo, automatiku i nuklearnu tehniku, Srebrno jezero, 03 – 06. juna, 2019. godine (2019):235-238,
https://hdl.handle.net/21.15107/rcub_vinar_10876 .

TY  - CONF
AU  - Ivanović, M. D.
AU  - Ring, M.
AU  - Hannink, J.
AU  - Baronio, F.
AU  - Hadžievski, Ljupčo
AU  - Eskofier, B.
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11867
AB  - Ventricular fibrillation (VF) represents the most frequent initial rhythm in out-of-hospital cardiac arrest (OHCA). It is characterized by rapid and disorganized contraction of the heart muscle cells which can lead to a sudden cardiac death. Optimizing defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation) by evaluating the probability of the successful outcome could significantly enhance resuscitation. Over the past few decades, different classification strategies were applied to predict the defibrillation outcome of OHCA patients, but none have achieved superior performance to be widely accepted and implemented in automated external defibrillators. All these reported strategies utilized conventional machine learning (ML) approach with feature engineering. Here, we compare the performances of 7 ML algorithms (Logistic Regression (LR), Naïve Bayes (NB), Decision tree (C4.5), AdaBoost M1(AB), Support Vector Machine (SVM), k Nearest Neighbour (kNN) and Random Forest (RF)) [1] with a novel approach based on convolutional neural networks (CNN). For conventional ML approach we engineered 28 “hand-crafted” features using time domain, frequency domain, time-frequency domain and non-linear dynamical analysis of the 4s pre-shock VF signal. The best performing feature combination was chosen using the wrapper feature selection method, which utilizes the classifier in evaluating selected feature subset. In deep learning approach, the CNN was capable of learning useful features from the raw VF signals. We used 3-stage CNN feature extractor, which contained convolution, rectified linear unit activation, dropout (only in training) and max-pooling and 2 layer perceptron for classification. Our results show that the SVM, kNN and RF outperformed other conventional ML algorithms. The mean accuracy obtained over 10 fold cross-validation of these 3 ML algorithms were: 81.5%, 81.8 % and 82.8 %, respectively. On the other hand deep learning approach demonstrated the superiority over the conventional ML approach with engineered features. Obtained averaged accuracy of 93.6 %, along with sensitivity of 98.8 % and specificity of 88.2 %, which satisfy the condition of at least 50 % specificity at 95 % sensitivity for being considered safe, indicate that the proposed CNN model can be considered as a safe and useful predictor for defibrillation decision.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
C3  - PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
T1  - Defibrillation outcome prediction as a potential guide to resuscitation
SP  - 51
EP  - 51
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11867
ER  - 

@conference{
author = "Ivanović, M. D. and Ring, M. and Hannink, J. and Baronio, F. and Hadžievski, Ljupčo and Eskofier, B.",
year = "2019",
abstract = "Ventricular fibrillation (VF) represents the most frequent initial rhythm in out-of-hospital cardiac arrest (OHCA). It is characterized by rapid and disorganized contraction of the heart muscle cells which can lead to a sudden cardiac death. Optimizing defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation) by evaluating the probability of the successful outcome could significantly enhance resuscitation. Over the past few decades, different classification strategies were applied to predict the defibrillation outcome of OHCA patients, but none have achieved superior performance to be widely accepted and implemented in automated external defibrillators. All these reported strategies utilized conventional machine learning (ML) approach with feature engineering. Here, we compare the performances of 7 ML algorithms (Logistic Regression (LR), Naïve Bayes (NB), Decision tree (C4.5), AdaBoost M1(AB), Support Vector Machine (SVM), k Nearest Neighbour (kNN) and Random Forest (RF)) [1] with a novel approach based on convolutional neural networks (CNN). For conventional ML approach we engineered 28 “hand-crafted” features using time domain, frequency domain, time-frequency domain and non-linear dynamical analysis of the 4s pre-shock VF signal. The best performing feature combination was chosen using the wrapper feature selection method, which utilizes the classifier in evaluating selected feature subset. In deep learning approach, the CNN was capable of learning useful features from the raw VF signals. We used 3-stage CNN feature extractor, which contained convolution, rectified linear unit activation, dropout (only in training) and max-pooling and 2 layer perceptron for classification. Our results show that the SVM, kNN and RF outperformed other conventional ML algorithms. The mean accuracy obtained over 10 fold cross-validation of these 3 ML algorithms were: 81.5%, 81.8 % and 82.8 %, respectively. On the other hand deep learning approach demonstrated the superiority over the conventional ML approach with engineered features. Obtained averaged accuracy of 93.6 %, along with sensitivity of 98.8 % and specificity of 88.2 %, which satisfy the condition of at least 50 % specificity at 95 % sensitivity for being considered safe, indicate that the proposed CNN model can be considered as a safe and useful predictor for defibrillation decision.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade",
journal = "PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts",
title = "Defibrillation outcome prediction as a potential guide to resuscitation",
pages = "51-51",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11867"
}

Ivanović, M. D., Ring, M., Hannink, J., Baronio, F., Hadžievski, L.,& Eskofier, B.. (2019). Defibrillation outcome prediction as a potential guide to resuscitation. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade., 51-51.
https://hdl.handle.net/21.15107/rcub_vinar_11867

Ivanović MD, Ring M, Hannink J, Baronio F, Hadžievski L, Eskofier B. Defibrillation outcome prediction as a potential guide to resuscitation. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts. 2019;:51-51.
https://hdl.handle.net/21.15107/rcub_vinar_11867 .

Ivanović, M. D., Ring, M., Hannink, J., Baronio, F., Hadžievski, Ljupčo, Eskofier, B., "Defibrillation outcome prediction as a potential guide to resuscitation" in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts (2019):51-51,
https://hdl.handle.net/21.15107/rcub_vinar_11867 .

TY  - CONF
AU  - Mančić, Ana
AU  - Ivanović, Marija
AU  - Hermann-Avigliano, C.
AU  - Hadžievski, Ljupčo
AU  - Maluckov, Aleksandra
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11887
AB  - Extreme events (EE) continue to challenge researches in diverse fields of natural and social
sciences [1]. The traces of different dynamics of huge intensity light events recently observed
experimentally on the output facets of a SBN photorefractive crystal were challenge of this kind
for us. We investigate the statistical properties of high intensity events by adopting the standard
methods of the EEs detection and classification [2]. It was shown that these events were
inevitable in our experiment for a large set of parameters, which was confirmed by a simple
theoretical model based on the two-dimensional Schrödinger equation with saturable
nonlinearity. We distinguished two main EE regimes, one with speckles pattern and another one
with soliton-like structures.
In order to classify different EEs regimes we used the achievements of the deep learning
methods applied in various fields of science and implemented them in the EE framework [3]. We
applied the convolution neural network (CNN) architecture consisting of the 3-stage feature
extractor and a fully connected multi-layer perceptron to classify different high light intensity
profiles. These profiles were formed in the experiment and in the corresponding numerical
simulations of the light propagation through the SBN crystal [2]. Each feature learning stage
incorporated the convolution, ReLU nonlinear activation and max-pooling. Three high intensity
profiles: caustic-, soliton- and speckling-like were confronted to the linear dispersion one (i. e. no
RW regime). The train and test sets of data were formed from the light intensity profiles. The
network architecture and optimal hyperparameters were selected using 10 fold cross-validation.
The model performances were evaluated on the blindfolded test set after the model was trained
on the whole training set. When the combination of theoretical and experimental data were
considered, the overall accuracy of selecting the soliton and speckling regimes, which can be
associated with different types of extreme events was above 97%. The caustic regime which can
be considered as a nucleus of high intensity events was extracted correctly from the other
regimes, too with the accuracy of 97.51 %. Satisfying performances of the CNN based detector
and classifier of the high intensity events were an encouraging outcome for continuing the study.
We are interested in going towards the prediction of the system preferences for the formation of
high intensity events using the deep learning strategy, since these events usually have a
devastating effect in the systems.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
C3  - PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
T1  - Deep learning based classification of high intensity light patterns in photorefractive crystals
SP  - 175
EP  - 175
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11887
ER  - 

@conference{
author = "Mančić, Ana and Ivanović, Marija and Hermann-Avigliano, C. and Hadžievski, Ljupčo and Maluckov, Aleksandra",
year = "2019",
abstract = "Extreme events (EE) continue to challenge researches in diverse fields of natural and social
sciences [1]. The traces of different dynamics of huge intensity light events recently observed
experimentally on the output facets of a SBN photorefractive crystal were challenge of this kind
for us. We investigate the statistical properties of high intensity events by adopting the standard
methods of the EEs detection and classification [2]. It was shown that these events were
inevitable in our experiment for a large set of parameters, which was confirmed by a simple
theoretical model based on the two-dimensional Schrödinger equation with saturable
nonlinearity. We distinguished two main EE regimes, one with speckles pattern and another one
with soliton-like structures.
In order to classify different EEs regimes we used the achievements of the deep learning
methods applied in various fields of science and implemented them in the EE framework [3]. We
applied the convolution neural network (CNN) architecture consisting of the 3-stage feature
extractor and a fully connected multi-layer perceptron to classify different high light intensity
profiles. These profiles were formed in the experiment and in the corresponding numerical
simulations of the light propagation through the SBN crystal [2]. Each feature learning stage
incorporated the convolution, ReLU nonlinear activation and max-pooling. Three high intensity
profiles: caustic-, soliton- and speckling-like were confronted to the linear dispersion one (i. e. no
RW regime). The train and test sets of data were formed from the light intensity profiles. The
network architecture and optimal hyperparameters were selected using 10 fold cross-validation.
The model performances were evaluated on the blindfolded test set after the model was trained
on the whole training set. When the combination of theoretical and experimental data were
considered, the overall accuracy of selecting the soliton and speckling regimes, which can be
associated with different types of extreme events was above 97%. The caustic regime which can
be considered as a nucleus of high intensity events was extracted correctly from the other
regimes, too with the accuracy of 97.51 %. Satisfying performances of the CNN based detector
and classifier of the high intensity events were an encouraging outcome for continuing the study.
We are interested in going towards the prediction of the system preferences for the formation of
high intensity events using the deep learning strategy, since these events usually have a
devastating effect in the systems.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade",
journal = "PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts",
title = "Deep learning based classification of high intensity light patterns in photorefractive crystals",
pages = "175-175",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11887"
}

Mančić, A., Ivanović, M., Hermann-Avigliano, C., Hadžievski, L.,& Maluckov, A.. (2019). Deep learning based classification of high intensity light patterns in photorefractive crystals. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade., 175-175.
https://hdl.handle.net/21.15107/rcub_vinar_11887

Mančić A, Ivanović M, Hermann-Avigliano C, Hadžievski L, Maluckov A. Deep learning based classification of high intensity light patterns in photorefractive crystals. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts. 2019;:175-175.
https://hdl.handle.net/21.15107/rcub_vinar_11887 .

Mančić, Ana, Ivanović, Marija, Hermann-Avigliano, C., Hadžievski, Ljupčo, Maluckov, Aleksandra, "Deep learning based classification of high intensity light patterns in photorefractive crystals" in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts (2019):175-175,
https://hdl.handle.net/21.15107/rcub_vinar_11887 .

TY  - CONF
AU  - Kršić, Jelena
AU  - Miletić, Marjan
AU  - Atanasoski, Vladimir
AU  - Hadžievski, Ljupčo
AU  - Ivanović, Marija
PY  - 2019
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/11892
AB  - The measurement of arterial blood pressure waveform can provide important data about arterial health, from which general cardiovascular health can be estimated. The arterial blood pressure wave is created by heart contraction which then propagates along the arterial tree. Along its path, the pressure wave causes the distention of arterial walls which consequently can be palpated and measured as micro-movements on the surface of the body. The most frequently used places on the body for recording of the blood pressure waveform are in the fingers and above the radial artery on the wrist. However, since waveforms recorded on the periphery of the body alter from central ones, there is the necessity for non-invasive measurements closer to the ascending aorta [1]. The purpose of this study was to evaluate the possibility of utilizing the superficial temporal artery (STA) as a potential candidate for obtaining arterial waveform recorded non-invasively by fiber grating sensors. The STA is a terminal branch of the external carotid artery and it represents the major artery of the head. The sites over the main branch (near the ear) and the frontal branch of the STA (near ocular area) are easily accessible ones with negligible amounts of fat and muscle tissues. Assessment tests were carried out by using fiber grating sensors (fiber Bragg grating (FBG) and long-period grating (LPG)) as sensors of the arterial distention movement. Here we were focused on the possibility to record the STA pulsations in healthy volunteers when the sensors were just placed on the skin over the STA and fixed with the tape or elastic bandage. Our results show that with this type of application, LPG technology outperformed FBG in a sense of sensitivity and signal to noise ratio. The reason possibly lies in the fact that cladding modes generated by an LPG are much more affected by arterial distention than back-propagating core modes of an FBG [2]. By using LPG sensor we were able to record STA pulsations in all volunteers.
PB  - Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade
C3  - PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
T1  - Optical fiber grating sensors for the measurement of superficial temporal artery pulsations
SP  - 121
EP  - 121
UR  - https://hdl.handle.net/21.15107/rcub_vinar_11892
ER  - 

@conference{
author = "Kršić, Jelena and Miletić, Marjan and Atanasoski, Vladimir and Hadžievski, Ljupčo and Ivanović, Marija",
year = "2019",
abstract = "The measurement of arterial blood pressure waveform can provide important data about arterial health, from which general cardiovascular health can be estimated. The arterial blood pressure wave is created by heart contraction which then propagates along the arterial tree. Along its path, the pressure wave causes the distention of arterial walls which consequently can be palpated and measured as micro-movements on the surface of the body. The most frequently used places on the body for recording of the blood pressure waveform are in the fingers and above the radial artery on the wrist. However, since waveforms recorded on the periphery of the body alter from central ones, there is the necessity for non-invasive measurements closer to the ascending aorta [1]. The purpose of this study was to evaluate the possibility of utilizing the superficial temporal artery (STA) as a potential candidate for obtaining arterial waveform recorded non-invasively by fiber grating sensors. The STA is a terminal branch of the external carotid artery and it represents the major artery of the head. The sites over the main branch (near the ear) and the frontal branch of the STA (near ocular area) are easily accessible ones with negligible amounts of fat and muscle tissues. Assessment tests were carried out by using fiber grating sensors (fiber Bragg grating (FBG) and long-period grating (LPG)) as sensors of the arterial distention movement. Here we were focused on the possibility to record the STA pulsations in healthy volunteers when the sensors were just placed on the skin over the STA and fixed with the tape or elastic bandage. Our results show that with this type of application, LPG technology outperformed FBG in a sense of sensitivity and signal to noise ratio. The reason possibly lies in the fact that cladding modes generated by an LPG are much more affected by arterial distention than back-propagating core modes of an FBG [2]. By using LPG sensor we were able to record STA pulsations in all volunteers.",
publisher = "Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade",
journal = "PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts",
title = "Optical fiber grating sensors for the measurement of superficial temporal artery pulsations",
pages = "121-121",
url = "https://hdl.handle.net/21.15107/rcub_vinar_11892"
}

Kršić, J., Miletić, M., Atanasoski, V., Hadžievski, L.,& Ivanović, M.. (2019). Optical fiber grating sensors for the measurement of superficial temporal artery pulsations. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts
Belgrade : Vinča Institute of Nuclear Sciences, University of Belgrade., 121-121.
https://hdl.handle.net/21.15107/rcub_vinar_11892

Kršić J, Miletić M, Atanasoski V, Hadžievski L, Ivanović M. Optical fiber grating sensors for the measurement of superficial temporal artery pulsations. in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts. 2019;:121-121.
https://hdl.handle.net/21.15107/rcub_vinar_11892 .

Kršić, Jelena, Miletić, Marjan, Atanasoski, Vladimir, Hadžievski, Ljupčo, Ivanović, Marija, "Optical fiber grating sensors for the measurement of superficial temporal artery pulsations" in PHOTONICA2019 : 7th International School and Conference on Photonics & Machine Learning with Photonics Symposium : Book of abstracts (2019):121-121,
https://hdl.handle.net/21.15107/rcub_vinar_11892 .

TY  - JOUR
AU  - Ivanović, Marija D.
AU  - Petrović, Jovana S.
AU  - Savić, Andrej
AU  - Gligorić, Goran
AU  - Miletić, Marjan
AU  - Vukčević, Miodrag
AU  - Bojović, Boško
AU  - Hadžievski, Ljupčo
AU  - Allsop, Thomas P.
AU  - Webb, David J.
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7637
AB  - Objective: The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism. Approach: The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence. We propose a technique that uses the measurement of chest-wall curvature by a long-period fibre-grating sensor. The sensor was applied externally to the rib-cage and interrogated in the lateral (edge) filtering scheme. The study was performed on 34 healthy volunteers. Statistical data analysis of the time lag between the fibregrating sensor and the reference pneumotachograph was preceded by the removal of the unwanted heartbeat signal by wavelet transform processing. Main results: The results show a consistent fibregrating signal advance with respect to the standard pneumatic signal by (230 +/- 100) ms in both the inspiratory and expiratory phases. We further show that heart activity removal yields a tremendous improvement in sensor accuracy by reducing it from 60 ml to 0.3 ml. Significance: The results indicate that the proposed measurement technique may lead to a more reliable triggering decision. Its imperviousness to air leaks, non-invasiveness, low-cost and ease of implementation offer good prospects for applications in both clinical and homecare ventilation.
T2  - Physiological Measurement
T1  - Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering
VL  - 39
IS  - 4
SP  - 045009
DO  - 10.1088/1361-6579/aab7ac
ER  - 

@article{
author = "Ivanović, Marija D. and Petrović, Jovana S. and Savić, Andrej and Gligorić, Goran and Miletić, Marjan and Vukčević, Miodrag and Bojović, Boško and Hadžievski, Ljupčo and Allsop, Thomas P. and Webb, David J.",
year = "2018",
abstract = "Objective: The ventilators involved in non-invasive mechanical ventilation commonly provide ventilator support via a facemask. The interface of the mask with a patient promotes air leaks that cause errors in the feedback information provided by a pneumatic sensor and hence patient-ventilator asynchrony with multiple negative consequences. Our objective is to test the possibility of using chest-wall motion measured by an optical fibre-grating sensor as a more accurate non-invasive ventilator triggering mechanism. Approach: The basic premise of our approach is that the measurement accuracy can be improved by using a triggering signal that precedes pneumatic triggering in the neuro-ventilatory coupling sequence. We propose a technique that uses the measurement of chest-wall curvature by a long-period fibre-grating sensor. The sensor was applied externally to the rib-cage and interrogated in the lateral (edge) filtering scheme. The study was performed on 34 healthy volunteers. Statistical data analysis of the time lag between the fibregrating sensor and the reference pneumotachograph was preceded by the removal of the unwanted heartbeat signal by wavelet transform processing. Main results: The results show a consistent fibregrating signal advance with respect to the standard pneumatic signal by (230 +/- 100) ms in both the inspiratory and expiratory phases. We further show that heart activity removal yields a tremendous improvement in sensor accuracy by reducing it from 60 ml to 0.3 ml. Significance: The results indicate that the proposed measurement technique may lead to a more reliable triggering decision. Its imperviousness to air leaks, non-invasiveness, low-cost and ease of implementation offer good prospects for applications in both clinical and homecare ventilation.",
journal = "Physiological Measurement",
title = "Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering",
volume = "39",
number = "4",
pages = "045009",
doi = "10.1088/1361-6579/aab7ac"
}

Ivanović, M. D., Petrović, J. S., Savić, A., Gligorić, G., Miletić, M., Vukčević, M., Bojović, B., Hadžievski, L., Allsop, T. P.,& Webb, D. J.. (2018). Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering. in Physiological Measurement, 39(4), 045009.
https://doi.org/10.1088/1361-6579/aab7ac

Ivanović MD, Petrović JS, Savić A, Gligorić G, Miletić M, Vukčević M, Bojović B, Hadžievski L, Allsop TP, Webb DJ. Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering. in Physiological Measurement. 2018;39(4):045009.
doi:10.1088/1361-6579/aab7ac .

Ivanović, Marija D., Petrović, Jovana S., Savić, Andrej, Gligorić, Goran, Miletić, Marjan, Vukčević, Miodrag, Bojović, Boško, Hadžievski, Ljupčo, Allsop, Thomas P., Webb, David J., "Real-time chest-wall-motion tracking by a single optical fibre grating: a prospective method for ventilator triggering" in Physiological Measurement, 39, no. 4 (2018):045009,
https://doi.org/10.1088/1361-6579/aab7ac . .

TY  - JOUR
AU  - Mančić, Ana
AU  - Baronio, Fabio
AU  - Hadžievski, Ljupčo
AU  - Wabnitz, Stefan
AU  - Maluckov, Aleksandra
PY  - 2018
UR  - https://link.aps.org/doi/10.1103/PhysRevE.98.012209
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7797
AB  - We present a statistical analysis based on the height and return-time probabilities of high-amplitude wave events in both focusing and defocusing Manakov systems. We find that analytical rational or semirational solutions, associated with extreme, rogue wave (RW) structures, are the leading high-amplitude events in this system. We define the thresholds for classifying an extreme wave event as a RW. Our results indicate that there is a strong relationship between the type of RW and the mechanism which is responsible for its creation. Initially, high-amplitude events originate from modulation instability. Upon subsequent evolution, the interaction among these events prevails as the mechanism for RW creation. We suggest a strategy for confirming the basic properties of different extreme events. This involves the definition of proper statistical measures at each stage of the RW dynamics. Our results point to the need for redefining criteria for identifying RW events.
T2  - Physical Review E
T1  - Statistics of vector Manakov rogue waves
VL  - 98
IS  - 1
SP  - 012209
DO  - 10.1103/PhysRevE.98.012209
ER  - 

@article{
author = "Mančić, Ana and Baronio, Fabio and Hadžievski, Ljupčo and Wabnitz, Stefan and Maluckov, Aleksandra",
year = "2018",
abstract = "We present a statistical analysis based on the height and return-time probabilities of high-amplitude wave events in both focusing and defocusing Manakov systems. We find that analytical rational or semirational solutions, associated with extreme, rogue wave (RW) structures, are the leading high-amplitude events in this system. We define the thresholds for classifying an extreme wave event as a RW. Our results indicate that there is a strong relationship between the type of RW and the mechanism which is responsible for its creation. Initially, high-amplitude events originate from modulation instability. Upon subsequent evolution, the interaction among these events prevails as the mechanism for RW creation. We suggest a strategy for confirming the basic properties of different extreme events. This involves the definition of proper statistical measures at each stage of the RW dynamics. Our results point to the need for redefining criteria for identifying RW events.",
journal = "Physical Review E",
title = "Statistics of vector Manakov rogue waves",
volume = "98",
number = "1",
pages = "012209",
doi = "10.1103/PhysRevE.98.012209"
}

Mančić, A., Baronio, F., Hadžievski, L., Wabnitz, S.,& Maluckov, A.. (2018). Statistics of vector Manakov rogue waves. in Physical Review E, 98(1), 012209.
https://doi.org/10.1103/PhysRevE.98.012209

Mančić A, Baronio F, Hadžievski L, Wabnitz S, Maluckov A. Statistics of vector Manakov rogue waves. in Physical Review E. 2018;98(1):012209.
doi:10.1103/PhysRevE.98.012209 .

Mančić, Ana, Baronio, Fabio, Hadžievski, Ljupčo, Wabnitz, Stefan, Maluckov, Aleksandra, "Statistics of vector Manakov rogue waves" in Physical Review E, 98, no. 1 (2018):012209,
https://doi.org/10.1103/PhysRevE.98.012209 . .

TY  - JOUR
AU  - Mančić, Ana
AU  - Baronio, Fabio
AU  - Hadžievski, Ljupčo
AU  - Wabnitz, Stefan
AU  - Maluckov, Aleksandra
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/7798
UR  - https://arxiv.org/pdf/1807.01941.pdf
AB  - We present a statistical analysis based on the height and return-time probabilities of high-amplitude wave events in both focusing and defocusing Manakov systems. We find that analytical rational or semirational solutions, associated with extreme, rogue wave (RW) structures, are the leading high-amplitude events in this system. We define the thresholds for classifying an extreme wave event as a RW. Our results indicate that there is a strong relationship between the type of RW and the mechanism which is responsible for its creation. Initially, high-amplitude events originate from modulation instability. Upon subsequent evolution, the interaction among these events prevails as the mechanism for RW creation. We suggest a strategy for confirming the basic properties of different extreme events. This involves the definition of proper statistical measures at each stage of the RW dynamics. Our results point to the need for redefining criteria for identifying RW events.
T2  - Physical Review E
T1  - Statistics of vector Manakov rogue waves
VL  - 98
IS  - 1
SP  - 012209
DO  - 10.1103/PhysRevE.98.012209
ER  - 

@article{
author = "Mančić, Ana and Baronio, Fabio and Hadžievski, Ljupčo and Wabnitz, Stefan and Maluckov, Aleksandra",
year = "2018",
abstract = "We present a statistical analysis based on the height and return-time probabilities of high-amplitude wave events in both focusing and defocusing Manakov systems. We find that analytical rational or semirational solutions, associated with extreme, rogue wave (RW) structures, are the leading high-amplitude events in this system. We define the thresholds for classifying an extreme wave event as a RW. Our results indicate that there is a strong relationship between the type of RW and the mechanism which is responsible for its creation. Initially, high-amplitude events originate from modulation instability. Upon subsequent evolution, the interaction among these events prevails as the mechanism for RW creation. We suggest a strategy for confirming the basic properties of different extreme events. This involves the definition of proper statistical measures at each stage of the RW dynamics. Our results point to the need for redefining criteria for identifying RW events.",
journal = "Physical Review E",
title = "Statistics of vector Manakov rogue waves",
volume = "98",
number = "1",
pages = "012209",
doi = "10.1103/PhysRevE.98.012209"
}

Mančić, A., Baronio, F., Hadžievski, L., Wabnitz, S.,& Maluckov, A.. (2018). Statistics of vector Manakov rogue waves. in Physical Review E, 98(1), 012209.
https://doi.org/10.1103/PhysRevE.98.012209

Mančić A, Baronio F, Hadžievski L, Wabnitz S, Maluckov A. Statistics of vector Manakov rogue waves. in Physical Review E. 2018;98(1):012209.
doi:10.1103/PhysRevE.98.012209 .

Mančić, Ana, Baronio, Fabio, Hadžievski, Ljupčo, Wabnitz, Stefan, Maluckov, Aleksandra, "Statistics of vector Manakov rogue waves" in Physical Review E, 98, no. 1 (2018):012209,
https://doi.org/10.1103/PhysRevE.98.012209 . .

TY  - JOUR
AU  - Ivanović, Marija D.
AU  - Ring, Matthias
AU  - Baronio, Fabio
AU  - Calza, Stefano
AU  - Vukčević, Vladan
AU  - Hadžievski, Ljupčo
AU  - Maluckov, Aleksandra
AU  - Eskofier, Bjoern Michael
PY  - 2018
UR  - http://stacks.iop.org/2057-1976/5/i=1/a=015012?key=crossref.179380a6d1fbac3633b726787a95feb5
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/8095
AB  - Objective: Algorithms to predict shock outcome based on ventricular fibrillation (VF) waveform features are potentially useful tool to optimize defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation). Researchers have investigated numerous predictive features and classification methods using single VF feature and/or their combinations, however reported predictabilities are not consistent. The purpose of this study was to validate whether combining VF features can enhance the prediction accuracy in comparison to single feature. Approach: The analysis was performed in 3 stages: feature extraction, preprocessing and feature selection and classification. Twenty eight predictive features were calculated on 4s episode of the pre-shock VF signal. The preprocessing included instances normalization and oversampling. Seven machine learning algorithms were employed for selecting the best performin single feature and combination of features using wrapper method: Logistic Regression (LR), Naïve-Bayes (NB), Decision tree (C4.5), AdaBoost.M1 (AB), Support Vector Machine (SVM), Nearest Neighbour (NN) and Random Forest (RF). Evaluation of the algorithms was performed by nested 10 fold cross-validation procedure. Main results: A total of 251 unbalanced first shocks (195 unsuccessful and 56 successful) were oversampled to 195 instances in each class. Performance metric based on average accuracy of feature combination has shown that LR and NB exhibit no improvement, C4.5 and AB an improvement not greater than 1% and SVM, NN and RF an improvement greater than 5% in predicting defibrillation outcome in comparison to the best single feature. Significance: By performing wrapper method to select best performing feature combination the non-linear machine learning strategies (SVM, NN, RF) can improve defibrillation prediction performance. © 2018 IOP Publishing Ltd.
T2  - Biomedical Physics and Engineering Express
T1  - ECG derived feature combination versus single feature in predicting defibrillation success in out-of-hospital cardiac arrested patients
VL  - 5
IS  - 1
SP  - 015012
DO  - 10.1088/2057-1976/aaebec
ER  - 

@article{
author = "Ivanović, Marija D. and Ring, Matthias and Baronio, Fabio and Calza, Stefano and Vukčević, Vladan and Hadžievski, Ljupčo and Maluckov, Aleksandra and Eskofier, Bjoern Michael",
year = "2018",
abstract = "Objective: Algorithms to predict shock outcome based on ventricular fibrillation (VF) waveform features are potentially useful tool to optimize defibrillation strategy (immediate defibrillation versus cardiopulmonary resuscitation). Researchers have investigated numerous predictive features and classification methods using single VF feature and/or their combinations, however reported predictabilities are not consistent. The purpose of this study was to validate whether combining VF features can enhance the prediction accuracy in comparison to single feature. Approach: The analysis was performed in 3 stages: feature extraction, preprocessing and feature selection and classification. Twenty eight predictive features were calculated on 4s episode of the pre-shock VF signal. The preprocessing included instances normalization and oversampling. Seven machine learning algorithms were employed for selecting the best performin single feature and combination of features using wrapper method: Logistic Regression (LR), Naïve-Bayes (NB), Decision tree (C4.5), AdaBoost.M1 (AB), Support Vector Machine (SVM), Nearest Neighbour (NN) and Random Forest (RF). Evaluation of the algorithms was performed by nested 10 fold cross-validation procedure. Main results: A total of 251 unbalanced first shocks (195 unsuccessful and 56 successful) were oversampled to 195 instances in each class. Performance metric based on average accuracy of feature combination has shown that LR and NB exhibit no improvement, C4.5 and AB an improvement not greater than 1% and SVM, NN and RF an improvement greater than 5% in predicting defibrillation outcome in comparison to the best single feature. Significance: By performing wrapper method to select best performing feature combination the non-linear machine learning strategies (SVM, NN, RF) can improve defibrillation prediction performance. © 2018 IOP Publishing Ltd.",
journal = "Biomedical Physics and Engineering Express",
title = "ECG derived feature combination versus single feature in predicting defibrillation success in out-of-hospital cardiac arrested patients",
volume = "5",
number = "1",
pages = "015012",
doi = "10.1088/2057-1976/aaebec"
}

Ivanović, M. D., Ring, M., Baronio, F., Calza, S., Vukčević, V., Hadžievski, L., Maluckov, A.,& Eskofier, B. M.. (2018). ECG derived feature combination versus single feature in predicting defibrillation success in out-of-hospital cardiac arrested patients. in Biomedical Physics and Engineering Express, 5(1), 015012.
https://doi.org/10.1088/2057-1976/aaebec

Ivanović MD, Ring M, Baronio F, Calza S, Vukčević V, Hadžievski L, Maluckov A, Eskofier BM. ECG derived feature combination versus single feature in predicting defibrillation success in out-of-hospital cardiac arrested patients. in Biomedical Physics and Engineering Express. 2018;5(1):015012.
doi:10.1088/2057-1976/aaebec .

Ivanović, Marija D., Ring, Matthias, Baronio, Fabio, Calza, Stefano, Vukčević, Vladan, Hadžievski, Ljupčo, Maluckov, Aleksandra, Eskofier, Bjoern Michael, "ECG derived feature combination versus single feature in predicting defibrillation success in out-of-hospital cardiac arrested patients" in Biomedical Physics and Engineering Express, 5, no. 1 (2018):015012,
https://doi.org/10.1088/2057-1976/aaebec . .

TY  - JOUR
AU  - Stojanović, Danka
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Hadžievski, Ljupčo
PY  - 2018
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/1909
AB  - We present a chiral metamaterial (CMM) made of periodically distributed compact elements in a form of twisted closed ring resonators designed to be operational in terahertz (THz) frequency range. We analyze the three observed resonances in the absorption spectra and electric field distribution of linearly polarized incident electromagnetic waves. It has been shown that they arise due to excitation of symmetric and antisymmetric modes and are dependent on the geometry of resonant elements as well as the periodicity of the system. For the case of incident circularly polarized waves, a phenomenon of circular dichroism was observed, and its origin and dependency on the geometrical parameters and metal and dielectric losses was examined. This study indicates that the proposed CMM has a high potential for applications in the design of different THz components.
T2  - Journal of Physics. D: Applied Physics
T1  - Terahertz chiral metamaterial based on twisted closed ring resonators
VL  - 51
IS  - 4
DO  - 10.1088/1361-6463/aaa06d
ER  - 

@article{
author = "Stojanović, Danka and Beličev, Petra and Gligorić, Goran and Hadžievski, Ljupčo",
year = "2018",
abstract = "We present a chiral metamaterial (CMM) made of periodically distributed compact elements in a form of twisted closed ring resonators designed to be operational in terahertz (THz) frequency range. We analyze the three observed resonances in the absorption spectra and electric field distribution of linearly polarized incident electromagnetic waves. It has been shown that they arise due to excitation of symmetric and antisymmetric modes and are dependent on the geometry of resonant elements as well as the periodicity of the system. For the case of incident circularly polarized waves, a phenomenon of circular dichroism was observed, and its origin and dependency on the geometrical parameters and metal and dielectric losses was examined. This study indicates that the proposed CMM has a high potential for applications in the design of different THz components.",
journal = "Journal of Physics. D: Applied Physics",
title = "Terahertz chiral metamaterial based on twisted closed ring resonators",
volume = "51",
number = "4",
doi = "10.1088/1361-6463/aaa06d"
}

Stojanović, D., Beličev, P., Gligorić, G.,& Hadžievski, L.. (2018). Terahertz chiral metamaterial based on twisted closed ring resonators. in Journal of Physics. D: Applied Physics, 51(4).
https://doi.org/10.1088/1361-6463/aaa06d

Stojanović D, Beličev P, Gligorić G, Hadžievski L. Terahertz chiral metamaterial based on twisted closed ring resonators. in Journal of Physics. D: Applied Physics. 2018;51(4).
doi:10.1088/1361-6463/aaa06d .

Stojanović, Danka, Beličev, Petra, Gligorić, Goran, Hadžievski, Ljupčo, "Terahertz chiral metamaterial based on twisted closed ring resonators" in Journal of Physics. D: Applied Physics, 51, no. 4 (2018),
https://doi.org/10.1088/1361-6463/aaa06d . .

TY  - CONF
AU  - Stojanović, Danka B.
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Hadžievski, Ljupčo
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12735
AB  - Chiral metamaterial consists of periodically placed resonant elements exhibiting chiral effects such as circular dichroism and optical activity. They appear due to the coupling of electric and magnetic fields which is result of an interaction of electromagnetic wave and chiral metamaterial. Numerous designs of chiral resonant elements are proposed providing applications for polarization conversion, filtering and absorption in THz frequency range [1, 2]. Here, we analyze propagation of electromagnetic waves through chiral metamaterial composed of twisted closed ring resonators (TCRR). The proposed chiral metamaterial is ultrathin structure which makes this design easy to fabricate and, at the same time, maintains effects which can be observed in conventional chiral 3D metamaterial structures. Dimensions of chiral elements are chosen to provide resonances within THz frequency range. Different geometrical parameters are varied in order to determine their influence on resonant frequency and losses [3]. For our TCRR chiral metamaterial structure, the analysis is made from microscopic as well as from macroscopic point of view. Through numerical simulations, we calculate electromagnetic field distribution, scattering coefficients, absorption and consequently, circular dichroism. Additionally, we examine losses in our chiral structure in terms of radiative and non-radiative ones [4] and explore its influence on the circular dichroism.
PB  - Belgrade : Institute of Physics Belgrade
C3  - PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
T1  - Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators
SP  - 190
EP  - 190
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12735
ER  - 

@conference{
author = "Stojanović, Danka B. and Beličev, Petra and Gligorić, Goran and Hadžievski, Ljupčo",
year = "2017",
abstract = "Chiral metamaterial consists of periodically placed resonant elements exhibiting chiral effects such as circular dichroism and optical activity. They appear due to the coupling of electric and magnetic fields which is result of an interaction of electromagnetic wave and chiral metamaterial. Numerous designs of chiral resonant elements are proposed providing applications for polarization conversion, filtering and absorption in THz frequency range [1, 2]. Here, we analyze propagation of electromagnetic waves through chiral metamaterial composed of twisted closed ring resonators (TCRR). The proposed chiral metamaterial is ultrathin structure which makes this design easy to fabricate and, at the same time, maintains effects which can be observed in conventional chiral 3D metamaterial structures. Dimensions of chiral elements are chosen to provide resonances within THz frequency range. Different geometrical parameters are varied in order to determine their influence on resonant frequency and losses [3]. For our TCRR chiral metamaterial structure, the analysis is made from microscopic as well as from macroscopic point of view. Through numerical simulations, we calculate electromagnetic field distribution, scattering coefficients, absorption and consequently, circular dichroism. Additionally, we examine losses in our chiral structure in terms of radiative and non-radiative ones [4] and explore its influence on the circular dichroism.",
publisher = "Belgrade : Institute of Physics Belgrade",
journal = "PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts",
title = "Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators",
pages = "190-190",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12735"
}

Stojanović, D. B., Beličev, P., Gligorić, G.,& Hadžievski, L.. (2017). Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts
Belgrade : Institute of Physics Belgrade., 190-190.
https://hdl.handle.net/21.15107/rcub_vinar_12735

Stojanović DB, Beličev P, Gligorić G, Hadžievski L. Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators. in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts. 2017;:190-190.
https://hdl.handle.net/21.15107/rcub_vinar_12735 .

Stojanović, Danka B., Beličev, Petra, Gligorić, Goran, Hadžievski, Ljupčo, "Electromagnetic wave propagation through chiral metamaterials composed of twisted closed ring resonators" in PHOTONICA2017 : 6th International School and Conference on Photonics and COST actions: MP1406 and MP1402 : Program and the book of abstracts (2017):190-190,
https://hdl.handle.net/21.15107/rcub_vinar_12735 .

TY  - CONF
AU  - Stojanović, Danka B.
AU  - Beličev, Petra
AU  - Gligorić, Goran
AU  - Radovanović, Jelena V.
AU  - Milanović, Vitomir B.
AU  - Hadžievski, Ljupčo
PY  - 2017
UR  - https://vinar.vin.bg.ac.rs/handle/123456789/12789
PB  - Belgrade : Institute of physics
C3  - 10th Photonics Workshop : Book of abstracts
T1  - Electromagnetic wave propagation through terahertz chiral metamaterials
SP  - 9
EP  - 9
UR  - https://hdl.handle.net/21.15107/rcub_vinar_12789
ER  - 

@conference{
author = "Stojanović, Danka B. and Beličev, Petra and Gligorić, Goran and Radovanović, Jelena V. and Milanović, Vitomir B. and Hadžievski, Ljupčo",
year = "2017",
publisher = "Belgrade : Institute of physics",
journal = "10th Photonics Workshop : Book of abstracts",
title = "Electromagnetic wave propagation through terahertz chiral metamaterials",
pages = "9-9",
url = "https://hdl.handle.net/21.15107/rcub_vinar_12789"
}

Stojanović, D. B., Beličev, P., Gligorić, G., Radovanović, J. V., Milanović, V. B.,& Hadžievski, L.. (2017). Electromagnetic wave propagation through terahertz chiral metamaterials. in 10th Photonics Workshop : Book of abstracts
Belgrade : Institute of physics., 9-9.
https://hdl.handle.net/21.15107/rcub_vinar_12789

Stojanović DB, Beličev P, Gligorić G, Radovanović JV, Milanović VB, Hadžievski L. Electromagnetic wave propagation through terahertz chiral metamaterials. in 10th Photonics Workshop : Book of abstracts. 2017;:9-9.
https://hdl.handle.net/21.15107/rcub_vinar_12789 .

Stojanović, Danka B., Beličev, Petra, Gligorić, Goran, Radovanović, Jelena V., Milanović, Vitomir B., Hadžievski, Ljupčo, "Electromagnetic wave propagation through terahertz chiral metamaterials" in 10th Photonics Workshop : Book of abstracts (2017):9-9,
https://hdl.handle.net/21.15107/rcub_vinar_12789 .