Gábor Hosszú

Long-term Phonocardiographic Fetal Home Monitoring for Telemedicine Systems

A novel compact method for fetal home monitoring optimized for long data acquisition time and low communication costs is presented. The method incorporates the preprocessing of disturbed acoustic signal received on the maternal abdomen. The basic idea of the preprocessing is that the detection of the systolic and diastolic sounds takes place on two separated frequency bands with autocorrelation on predicted time intervals. Measurements on 47 selected pregnant women have shown that the use of this method significantly reduces the amount of data to be transferred to the computer centre in the hospital, where only the very disturbed time periods have to be evaluated. Based on this method a new, phonocardiographic fetal telemedicine system can be built without time limitation of measurements

Fetal phonocardiography-Past and future possibilities

The paper presents an overview of the 15 year long development of fetal phonocardiography including the works on the applied signal processing methods for identification of sound components. Based on the improvements achieved on this field, the paper shows that beyond the traditional CTG test the phonocardiography may be successfully applied for long-term fetal measurements and home monitoring. In addition, by indication of heart murmurs based on a comprehensive analysis of the recorded heart sound congenital heart defects can also be detected together with additional features in the third trimester. This makes an early widespread screening possible combined with the prescribed CTG test even at home using a telemedicine system.

Extended Noninvasive Fetal Monitoring by Detailed Analysis of Data Measured With Phonocardiography

This paper presents a complex heuristic method for the evaluation of fetal heart sounds, applying simultaneously several algorithms, where the autocorrelation technique has been completed with the wavelet transform and the matching pursuit methods. In this way, a more reliable heart rate variability can be achieved and further parameters of the cardiac operation can be assessed in addition to the conventional cardiotocographic examination. This also comprises those parameters, which can be investigated only with long-term or continuous monitoring, and those, which rely on a very accurate estimation of the heart rate variability. The proposed method provides a way for assessing fetal heart murmurs, which is a completely new possibility for monitoring the well-being of the fetus.

Computer method for perinatal screening of cardiac murmur using fetal phonocardiography

The main purpose of this paper is to demonstrate the capability of fetal phonocardiographic measurements to indicate some congenital heart defects. It deals with the results of investigations carried out during the last four years involving 820 pregnant women. During the investigations fetal cardiac murmurs presenting typical waveforms and incidences of acoustic signals were recorded. Causes of these murmurs are suggested based on comparison with the well-known waveforms of infants and children. A sophisticated signal processing method for murmur discovery is presented, that is also useful for automatic perinatal screening after the 28th week of gestation. By these means low-risk population may also be fully tested for cardiac malfunctions.

An efficient adiabatic charge-recovery logic

We propose a novel dual-rail energy efficient adiabatic charge recovery logic. We completely eliminate nonadiabatic loss during the charge phase, but allow partial reversibility only at nodes with small capacitance, in order to keep the reversibility overhead low. We apply transistor size optimization for a given frequency to alleviate the problem of increasing energy loss at higher operating frequencies. In the case of the nodes with high capacitance, a recovery path is introduced to provide complete charge recovery. The simulation on test circuits with the threshold voltage of 0.8 V showed 34% power reduction on average with complete recovery over the already optimally sized circuit.

Experiences with fetal phonocardiographic telemonitoring and future possibilities

Phonocardiography (PCG) makes possible the examination of some fetal cardiac anomalies which otherwise usually remain undetected during pregnancy. The application of PCG in a telemonitoring system enhances its diagnostic capabilities, allowing long-term measurements even at home. The paper summarizes the intensive fetal monitoring campaign carried out in Hungary during the last three years that yielded useful experience regarding recent and future possibilities of fetal monitoring. Results collected from a large number of measurements suggest that PCG home monitoring may be a suitable screening method for fetal congenital heart diseases, even if surgical intervention in this phase of pregnancy is not easy.

Application of the Matching Pursuit Method in a Fetal Phonocardiographic Telemedicine System

A novel compact method for fetal home monitoring optimized for long data acquisition time has already been presented [1]. The method involves preprocessing a disturbed acoustic signal received on the maternal abdomen. The present work summarizes phenomena encountered during analysis of the incoming PCG signal, and describes further improvements made to the analysis system already in use including the application of the MP method to determining heartbeat lengths and identifying murmurs between heart sounds.

Fetal Breathing Transmission in Phonocardiographic Monitoring Telemedicine Systems

The phonocardiographic monitoring of fetal heart activity due to its passive nature enables extremely long measuring times providing thus the possibility of fetal breathing recovery. The long monitoring time is required because of the temporary appearing of breathing movement. However, the long measurement time and consequently the large amount of data to be transmitted to the hospitals computer centre may be costly on mobile phone network. To keep monitoring costs low an appropriate data compression should be applied assuring the transmission of all important features of the detected acoustic signal. The present work summarizes the results of the extension of the novel telemedicine system with measurement of breathing periodicity and the achieved compression level of acquisited data. The Golomb-Rice compression is applied for lossless transmission of the segmented beat cycles considering the importance of the given segments in order to obtain the most accurate transfer of beat-to-beat time and all irregular heart sounds

Enhancing Collaborative Intrusion Detection Methods Using a Kademlia Overlay Network

The two important problems of collaborative intrusion detection are aggregation and correlation of intrusion events. The enormous amount of data generated by detection probes requires significant network and computational capacity to be processed. In this article we show that a distributed hash table based approach can reduce both network and computational load of intrusion detection, while providing almost the same accuracy of detection as centralized solutions. The efficiency of data storage can be improved by selecting Kademlia as the underlying overlay network topology, as its routing can easily adapt to the dynamic properties of such an application.

Screening for congenital heart diseases by murmurs using telemedical phonocardiography

A large proportion of congenital heart diseases (CHD) remain undetected during pregnancy or even after birth. Many of them generate turbulent blood flow, resulting heart murmur. Doppler ultrasound cardiotocography (CTG) is suitable for the assessment of the fetal heart rate and some derived parameters, but it is inadequate for detecting heart murmurs. Although comprehensive examination can be carried out with echocardiography, it is expensive and requires expertise; therefore, it is not applicable for widespread screening. This paper presents a new possibility for screening for some CHDs using phonocardiography, which can be combined with Doppler ultrasound CTG as an extension of it. Furthermore it can be carried out at home allowing repeated measurements, which increases also the reliability of filtering out innocent murmurs. The diagnostic capability of this screening method is supported by a large number of evaluated fetal heart sound records. Moreover, according to experiences pregnant women prefer this reliable, easy to use method, which facilitates their examination.