Vl Ma - Academia.edu (original) (raw)

Papers by Vl Ma

BMC Neuroscience, Dec 1, 2015

Journal of Electrical Engineering, 2020

A mobile users’ network with power control on traffic channels, as it is GSM, is considered in th... more A mobile users’ network with power control on traffic channels, as it is GSM, is considered in this paper. It is analyzed the influence of busy channels reallocation on the necessary emission power. The main principle in reallocation is that users who need greatest power for their connections take traffic channels of the first carrier where power is always maximum. It is assessed that reallocation process is not more complicate than the simplest handover processes. It is proved that this method may be used to decrease emission power of carriers after the second one. Power saving depends on number of carriers, environmental propagation coefficient and users’ density distribution in the cell. The results are verified by originally developed simulation program.

Journal of Electrical Engineering, 2020

In this paper the properties of handover traffic are analyzed in the system with channel reservat... more In this paper the properties of handover traffic are analyzed in the system with channel reservation. The reservation of several traffic channels only for handover calls leads to probability of handover calls congestion decrease to the level of per mill or even lower. The congestion of all traffic channels in the neighbouring cells is the cause that handover traffic process deviates from the Poissonian distribution and this deviation is negligible, because handover calls congestion probability is very low. This low handover calls probability is also the reason why implementation of one equivalent cell instead of 6 neighbouring cells surrounding the central cell does not model satisfactory the traffic flow in the mobile network. The randomness of handover calls arrival to the central cell is tested by our originally developed simulation program. Coefficient of variation of time between handover calls arrival to the central cell is calculated as the result of simulation. We introduced...

Proceedings of the International Scientific Conference - Sinteza 2019, 2019

1Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje boles... more 1Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje bolesti, Zavod za gastroenterologiju, 2Sveučilište u Zagrebu, Farmaceutskobiokemijski fakultet, 3Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje bolesti, Zagreb, 4Sveučilište u Rijeci, Medicinski fakultet, Katedra za internu medicinu, Rijeka i 5Sveučilište u Zagrebu, Medicinski fakultet, Katedra za internu medicinu, Zagreb, Hrvatska

ITS'98 Proceedings. SBT/IEEE International Telecommunications Symposium (Cat. No.98EX202)

Sinusoidal signal generators represent an important part of communication systems, devices and ap... more Sinusoidal signal generators represent an important part of communication systems, devices and applications. The implementation of integrated digital signal processing in signal generation provides fast and accurate calculations. This paper describes and compares three well-known algorithms for sine wave signal generation with an aim to identifying the algorithm most suitable for practical applications

Tehnika, 2021

New modern technologies in mobile telephony overcome the possibilities of GSM systems. VAMOS tech... more New modern technologies in mobile telephony overcome the possibilities of GSM systems. VAMOS technique is one way to improve traffic properties of traditional GSM systems. Our aim is to analyze the level of this improvement achieved by VAMOS implementation. The number of traffic resources is doubled, but it is proved that traffic capacity is more than doubled for full rate connections implementation and more than quadrupled for half rate connections regardless of offered traffic for all values of emission power difference between 4dB and 10dB when considering two paired subchannels. There are two loss types in VAMOS systems: unpairing loss and traffic loss when all subchannels are busy. The values of these two loss types whose sum presents the total loss in VAMOS systems are determined by originally developed simulation program. The achievable total loss may be decreased for 45% or even more when allowable power difference between paired channels is increased from 4dB to 10dB.

Pediatrics & Neonatology, 2018

Journal of Process Management. New Technologies, 2013

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, Sep 12, 2017

To assess interrater agreement based on majority voting in visual scoring of neonatal seizures. A... more To assess interrater agreement based on majority voting in visual scoring of neonatal seizures. An online platform was designed based on a multicentre seizure EEG-database. Consensus decision based on 'majority voting' and interrater agreement was estimated using Fleiss' Kappa. The influences of different factors on agreement were determined. 1919 Events extracted from 280h EEG of 71 neonates were reviewed by 4 raters. Majority voting was applied to assign a seizure/non-seizure classification. 44% of events were classified with high, 36% with moderate, and 20% with poor agreement, resulting in a Kappa value of 0.39. 68% of events were labelled as seizures, and in 46%, all raters were convinced about electrographic seizures. The most common seizure duration was <30s. Raters agreed best for seizures lasting 60-120s. There was a significant difference in electrographic characteristics of seizures versus dubious events, with seizures having longer duration, higher power a...

International Journal of Cognitive Research in Science Engineering and Education, Dec 20, 2013

Neuroscience, Jan 11, 2016

Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal ... more Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 to 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant in...

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

Frontiers in Human Neuroscience, 2015

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

Signal recovery is one of the key techniques of compressive sensing (CS). It reconstructs the ori... more Signal recovery is one of the key techniques of compressive sensing (CS). It reconstructs the original signal from the linear sub-Nyquist measurements. Classical methods exploit the sparsity in one domain to formulate the L0 norm optimization. Recent investigation shows that some signals are sparse in multiple domains. To further improve the signal reconstruction performance, we can exploit this multi-sparsity to generate a new convex programming model. The latter is formulated with multiple sparsity constraints in multiple domains and the linear measurement fitting constraint. It improves signal recovery performance by additional a priori information. Since some EMG signals exhibit sparsity both in time and frequency domains, we take them as example in numerical experiments. Results show that the newly proposed method achieves better performance for multi-sparse signals.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011

We propose a novel approach for compressive sampling of the neonatal electro-encefalogram (EEG) d... more We propose a novel approach for compressive sampling of the neonatal electro-encefalogram (EEG) data. The method assumes that the set of EEG data is generated by linearly mixing a fewer number of source signals. Another assumption is that the sources are nearly-sparse in Gabor dictionary. The presented method, instead of compressing original EEG channels, first performs a data-reduction, and then compresses the obtained sources. With this approach we showed that the gain in reconstruction speed is 33%-50%, whereas the compression rate is enhanced by 33%.

Proceedings of the International Conference on Bio-inspired Systems and Signal Processing, 2015

2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012

EEG inter-burst interval (IBI) and its evolution is a robust parameter for grading hypoxic enceph... more EEG inter-burst interval (IBI) and its evolution is a robust parameter for grading hypoxic encephalopathy and prognostication in newborns with perinatal asphyxia. We present a reliable algorithm for the automatic detection of IBIs. This automated approach is based on adaptive segmentation of EEG, classification of segments and use of temporal profiles to describe the global distribution of EEG activity. A pediatric neurologist has blindly scored data from 8 newborns with perinatal postasphyxial encephalopathy varying from mild to severe. 15 minutes of EEG have been scored per patient, thus totaling 2 hours of EEG that was used for validation. The algorithm shows good detection accuracy and provides insight into challenging cases that are difficult to detect.

BMC Neuroscience, Dec 1, 2015

Journal of Electrical Engineering, 2020

A mobile users’ network with power control on traffic channels, as it is GSM, is considered in th... more A mobile users’ network with power control on traffic channels, as it is GSM, is considered in this paper. It is analyzed the influence of busy channels reallocation on the necessary emission power. The main principle in reallocation is that users who need greatest power for their connections take traffic channels of the first carrier where power is always maximum. It is assessed that reallocation process is not more complicate than the simplest handover processes. It is proved that this method may be used to decrease emission power of carriers after the second one. Power saving depends on number of carriers, environmental propagation coefficient and users’ density distribution in the cell. The results are verified by originally developed simulation program.

Journal of Electrical Engineering, 2020

In this paper the properties of handover traffic are analyzed in the system with channel reservat... more In this paper the properties of handover traffic are analyzed in the system with channel reservation. The reservation of several traffic channels only for handover calls leads to probability of handover calls congestion decrease to the level of per mill or even lower. The congestion of all traffic channels in the neighbouring cells is the cause that handover traffic process deviates from the Poissonian distribution and this deviation is negligible, because handover calls congestion probability is very low. This low handover calls probability is also the reason why implementation of one equivalent cell instead of 6 neighbouring cells surrounding the central cell does not model satisfactory the traffic flow in the mobile network. The randomness of handover calls arrival to the central cell is tested by our originally developed simulation program. Coefficient of variation of time between handover calls arrival to the central cell is calculated as the result of simulation. We introduced...

Proceedings of the International Scientific Conference - Sinteza 2019, 2019

1Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje boles... more 1Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje bolesti, Zavod za gastroenterologiju, 2Sveučilište u Zagrebu, Farmaceutskobiokemijski fakultet, 3Sveučilište u Zagrebu, Medicinski fakultet, Klinička bolnica Dubrava, Klinika za unutarnje bolesti, Zagreb, 4Sveučilište u Rijeci, Medicinski fakultet, Katedra za internu medicinu, Rijeka i 5Sveučilište u Zagrebu, Medicinski fakultet, Katedra za internu medicinu, Zagreb, Hrvatska

ITS'98 Proceedings. SBT/IEEE International Telecommunications Symposium (Cat. No.98EX202)

Sinusoidal signal generators represent an important part of communication systems, devices and ap... more Sinusoidal signal generators represent an important part of communication systems, devices and applications. The implementation of integrated digital signal processing in signal generation provides fast and accurate calculations. This paper describes and compares three well-known algorithms for sine wave signal generation with an aim to identifying the algorithm most suitable for practical applications

Tehnika, 2021

New modern technologies in mobile telephony overcome the possibilities of GSM systems. VAMOS tech... more New modern technologies in mobile telephony overcome the possibilities of GSM systems. VAMOS technique is one way to improve traffic properties of traditional GSM systems. Our aim is to analyze the level of this improvement achieved by VAMOS implementation. The number of traffic resources is doubled, but it is proved that traffic capacity is more than doubled for full rate connections implementation and more than quadrupled for half rate connections regardless of offered traffic for all values of emission power difference between 4dB and 10dB when considering two paired subchannels. There are two loss types in VAMOS systems: unpairing loss and traffic loss when all subchannels are busy. The values of these two loss types whose sum presents the total loss in VAMOS systems are determined by originally developed simulation program. The achievable total loss may be decreased for 45% or even more when allowable power difference between paired channels is increased from 4dB to 10dB.

Pediatrics & Neonatology, 2018

Journal of Process Management. New Technologies, 2013

Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology, Sep 12, 2017

To assess interrater agreement based on majority voting in visual scoring of neonatal seizures. A... more To assess interrater agreement based on majority voting in visual scoring of neonatal seizures. An online platform was designed based on a multicentre seizure EEG-database. Consensus decision based on 'majority voting' and interrater agreement was estimated using Fleiss' Kappa. The influences of different factors on agreement were determined. 1919 Events extracted from 280h EEG of 71 neonates were reviewed by 4 raters. Majority voting was applied to assign a seizure/non-seizure classification. 44% of events were classified with high, 36% with moderate, and 20% with poor agreement, resulting in a Kappa value of 0.39. 68% of events were labelled as seizures, and in 46%, all raters were convinced about electrographic seizures. The most common seizure duration was <30s. Raters agreed best for seizures lasting 60-120s. There was a significant difference in electrographic characteristics of seizures versus dubious events, with seizures having longer duration, higher power a...

International Journal of Cognitive Research in Science Engineering and Education, Dec 20, 2013

Neuroscience, Jan 11, 2016

Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal ... more Early intermittent cortical activity is thought to play a crucial role in the growth of neuronal network development, and large scale brain networks are known to provide the basis for higher brain functions. Yet, the early development of the large scale synchrony in cortical activations is unknown. Here, we tested the hypothesis that the early intermittent cortical activations seen in the human scalp EEG show a clear developmental course during the last trimester of pregnancy, the period of intensive growth of cortico-cortical connections. We recorded scalp EEG from altogether 22 premature infants at post-menstrual age between 30 to 44 weeks, and the early cortical synchrony was quantified using recently introduced activation synchrony index (ASI). The developmental correlations of ASI were computed for individual EEG signals as well as anatomically and mathematically defined spatial subgroups. We report two main findings. First, we observed a robust and statistically significant in...

2015 37th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 2015

Frontiers in Human Neuroscience, 2015

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2012

Signal recovery is one of the key techniques of compressive sensing (CS). It reconstructs the ori... more Signal recovery is one of the key techniques of compressive sensing (CS). It reconstructs the original signal from the linear sub-Nyquist measurements. Classical methods exploit the sparsity in one domain to formulate the L0 norm optimization. Recent investigation shows that some signals are sparse in multiple domains. To further improve the signal reconstruction performance, we can exploit this multi-sparsity to generate a new convex programming model. The latter is formulated with multiple sparsity constraints in multiple domains and the linear measurement fitting constraint. It improves signal recovery performance by additional a priori information. Since some EMG signals exhibit sparsity both in time and frequency domains, we take them as example in numerical experiments. Results show that the newly proposed method achieves better performance for multi-sparse signals.

Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Annual Conference, 2011

We propose a novel approach for compressive sampling of the neonatal electro-encefalogram (EEG) d... more We propose a novel approach for compressive sampling of the neonatal electro-encefalogram (EEG) data. The method assumes that the set of EEG data is generated by linearly mixing a fewer number of source signals. Another assumption is that the sources are nearly-sparse in Gabor dictionary. The presented method, instead of compressing original EEG channels, first performs a data-reduction, and then compresses the obtained sources. With this approach we showed that the gain in reconstruction speed is 33%-50%, whereas the compression rate is enhanced by 33%.

Proceedings of the International Conference on Bio-inspired Systems and Signal Processing, 2015

2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, 2012

EEG inter-burst interval (IBI) and its evolution is a robust parameter for grading hypoxic enceph... more EEG inter-burst interval (IBI) and its evolution is a robust parameter for grading hypoxic encephalopathy and prognostication in newborns with perinatal asphyxia. We present a reliable algorithm for the automatic detection of IBIs. This automated approach is based on adaptive segmentation of EEG, classification of segments and use of temporal profiles to describe the global distribution of EEG activity. A pediatric neurologist has blindly scored data from 8 newborns with perinatal postasphyxial encephalopathy varying from mild to severe. 15 minutes of EEG have been scored per patient, thus totaling 2 hours of EEG that was used for validation. The algorithm shows good detection accuracy and provides insight into challenging cases that are difficult to detect.