202 research outputs found
Design Space Exploration of a Spiking LSM Classifier for RADAR applications
No full textRecent trends in platforms for the consumer market increased the need for low-power and reliable classification engines. Spiking Neural Network (SNN) is a new technology that promises to deliver 4 orders of magnitude more performance per watt than competing solutions. Moreover, the adoption of RADAR for gesture detection provides higher reliability compared to image sensors. However, no accepted topology for a temporal SNN classifier focusing on RADAR data exists. In addition, previous research did not account for several design limitations necessary to export the design in analog hardware. In this work, we explore the possible SNN topologies and propose a Liquid State Machine (LSM) with fully-supervised readout, suitable to be exported to a mixed-signal neuron array. A complete parametric model of the architecture and learning rule has been implemented in a simulation environment. Following, the design space was explored in search for the optimal operating region. By analysing the results, we: (i) highlight and explain the effects of several parameters and the trade-off between accuracy and power consumption; (ii) emphasize the need for a good balance between global excitation and inhibition in the LSM; (iii) suggest that the limitations of the proposed design point to the importance of an adequate feature extraction for a stable LSM behaviour and to the unpredictable nature of the SNN backpropagation algorithm, caused by the non differentiability of the spike signals.Electrical Engineering | Embedded System
COMPUTER-ASSISTED ANALYSIS OF NORMAL 2ND TRIMESTER FETAL HEART-RATE PATTERNS
No full textA software package for computer-assisted analysis of antenatal fetal heart rate (FHR) patterns has been commercially available from 1989. Reference ranges for the third trimester of pregnancy have been established. In order to obtain reference values for the second trimester, one hour FHR recordings were made between 20 and 29 weeks gestation in 77 women with uncomplicated pregnancies. There was a significant increase of (medium term) FHR variation and of the number of accelerations from 20 to 29 weeks (r = 0.48, p <0.01 and r = 0.34, p <0.01 respectively). The lower limit of normal FHR variation (mean - 2 SD's) increased from 18 msec at 20 weeks to 28 msec at 28 weeks. Furthermore, a 30 minute recording appeared to be sufficient to obtain a reliable impression of FHR variation. Short term FHR variation, a measure of FHR variation that facilitates the identification of sinusoidal FHR patterns, also increased significantly between 20 and 29 weeks (r = 0.61, p <0.01). Delerations (> 20 heats/min and greater-than-or-equal-to 30 seconds) were present in 54% of the recordings and are a more or less common phenomenon at this age.It is concluded that during the second trimester FHR variation differs considerably from that in the third trimester. This should be taken into account in the interpretation of second trimester FHR records.</p
CONTINUOUS MATERNAL HYPEROXYGENATION IN THE TREATMENT OF EARLY FETAL GROWTH-RETARDATION
No full textContinuous maternal hyperoxygenation treatment (2.5 l/min by means of a nasopharyngeal cannula) was given in four patients presenting with intrauterine growth-retarded (IUGR) fetuses and decelerative fetal heart rate (FHR) patterns at 27-28 weeks of gestation. The effect of maternal hyperoxia was studied longitudinally. Neither the incidence of generalized fetal movements (FGM%) nor the pulsatility index of the internal carotid artery increased under hyperoxia. In fact, both variables decreased progressively. FHR variation was abnormal prior to the start of hyperoxygenation and showed a slight but transient increase. On average, maternal hyperoxygenation 'resulted' in a prolongation of the duration of pregnancy of 9 days. The neonatal mortality was similar in the study group as compared to a control group of IUGR infants. However, hypoglycemia, thrombocytopenia and disseminated intravascular coagulation at birth were found more frequently in the study group. Conversely, blood gas abnormalities were less frequent in the fetuses of mothers that were treated with oxygen. We conclude that positive effects of oxygen therapy in IUGR fetuses remain uncertain and that detrimental effects due to prolongation of intrauterine malnutrition have not as yet been sufficiently excluded
CONTINUOUS MATERNAL HYPEROXYGENATION IN THE TREATMENT OF EARLY FETAL GROWTH-RETARDATION
No full textContinuous maternal hyperoxygenation treatment (2.5 l/min by means of a nasopharyngeal cannula) was given in four patients presenting with intrauterine growth-retarded (IUGR) fetuses and decelerative fetal heart rate (FHR) patterns at 27-28 weeks of gestation. The effect of maternal hyperoxia was studied longitudinally. Neither the incidence of generalized fetal movements (FGM%) nor the pulsatility index of the internal carotid artery increased under hyperoxia. In fact, both variables decreased progressively. FHR variation was abnormal prior to the start of hyperoxygenation and showed a slight but transient increase. On average, maternal hyperoxygenation 'resulted' in a prolongation of the duration of pregnancy of 9 days. The neonatal mortality was similar in the study group as compared to a control group of IUGR infants. However, hypoglycemia, thrombocytopenia and disseminated intravascular coagulation at birth were found more frequently in the study group. Conversely, blood gas abnormalities were less frequent in the fetuses of mothers that were treated with oxygen. We conclude that positive effects of oxygen therapy in IUGR fetuses remain uncertain and that detrimental effects due to prolongation of intrauterine malnutrition have not as yet been sufficiently excluded.</p
PREDICTION OF FETAL ACIDEMIA IN INTRAUTERINE GROWTH-RETARDATION - COMPARISON OF QUANTIFIED FETAL ACTIVITY WITH BIOPHYSICAL PROFILE SCORE
No full textObjective To study the relation between quantified fetal movements and fetal activity assessed by the biophysical profile score and the pH in umbilical arterial blood at elective caesarean section. Design Fetal activity was assessed within 24 h prior to caesarean section for decelerative fetal heart rate patterns both by quantification (% of time spent moving) and by applying the biophysical profile score (BPS) criteria. Setting Department of Obstetrics, University Hospital. Subjects Nineteen growth retarded fetuses. Main outcome measures Fetal generalised movements (FGM%), fetal breathing movements (FBM%), total fetal activity (TFA% = FGM% + FBM%); FGM, FBM and tone as assessed according the biophysical profile score (BPS); umbilical arterial pH. Results In all 11 acidaemic fetuses (pH Conclusion TFA
Changes in antepartum heart-rate patterns with progressive deterioration of the fetal condition
No full textChanges in antepartum heart-rate patterns with progressive deterioration of the fetal condition
No full textCOMPUTER-ASSISTED ANALYSIS OF NORMAL 2ND TRIMESTER FETAL HEART-RATE PATTERNS
No full textA software package for computer-assisted analysis of antenatal fetal heart rate (FHR) patterns has been commercially available from 1989. Reference ranges for the third trimester of pregnancy have been established. In order to obtain reference values for the second trimester, one hour FHR recordings were made between 20 and 29 weeks gestation in 77 women with uncomplicated pregnancies. There was a significant increase of (medium term) FHR variation and of the number of accelerations from 20 to 29 weeks (r = 0.48, p 20 heats/min and greater-than-or-equal-to 30 seconds) were present in 54% of the recordings and are a more or less common phenomenon at this age. It is concluded that during the second trimester FHR variation differs considerably from that in the third trimester. This should be taken into account in the interpretation of second trimester FHR records
PREDICTION OF FETAL ACIDEMIA IN INTRAUTERINE GROWTH-RETARDATION - COMPARISON OF QUANTIFIED FETAL ACTIVITY WITH BIOPHYSICAL PROFILE SCORE
No full textObjective To study the relation between quantified fetal movements and fetal activity assessed by the biophysical profile score and the pH in umbilical arterial blood at elective caesarean section.Design Fetal activity was assessed within 24 h prior to caesarean section for decelerative fetal heart rate patterns both by quantification (% of time spent moving) and by applying the biophysical profile score (BPS) criteria.Setting Department of Obstetrics, University Hospital.Subjects Nineteen growth retarded fetuses.Main outcome measures Fetal generalised movements (FGM%), fetal breathing movements (FBM%), total fetal activity (TFA% = FGM% + FBM%); FGM, FBM and tone as assessed according the biophysical profile score (BPS); umbilical arterial pH.Results In all 11 acidaemic fetuses (pHConclusion TFA%</p
A new scenario of turbulence theory and an application to pipe turbulence
No full textA new general scenario of turbulence theory is proposed and applied to pipe-flow turbulence. The theory supports tranverse traveling waves which suffer energy loss by internal friction (Joule-like effect). Its predictions are consistent with some characteristic features of pipe turbulence found in recent experiments: (i) existence of traveling waves and their important function and (ii) existence of two large scales (LSM and VLSM), both in turbulent state. In fact, predicted waves are characterized by two scales (wave-length and damping-length). Bulk energy dissipation is expressed unexpectedly in a form analogous to a model of eddy-viscosity
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