scholarly journals Comparison of time‐domain parabolic equation and measured ocean impulse responses in a range‐dependent environment

1993 ◽  
Vol 93 (4) ◽  
pp. 2427-2427
Author(s):  
James H. Leclere ◽  
Robert L. Field
Keyword(s):  
Parabolic Equation ◽  
Time Domain ◽  
Impulse Responses

Time‐domain solutions for Rayleigh and Stoneley waves using the single‐scattering parabolic equation method.

2008 ◽  
Vol 124 (4) ◽  
pp. 2585-2585
Author(s):  
Adam M. Metzler ◽  
William L. Siegmann ◽  
Michael D. Collins ◽  
Robert A. Zingarelli ◽  
Stanley A. Chin‐Bing
Keyword(s):  
Parabolic Equation ◽  
Time Domain ◽  
Single Scattering ◽  
Equation Method ◽  
Stoneley Waves ◽  
Parabolic Equation Method

scholarly journals Cardiorespiratory kinetics in exercise physiology: estimates and predictions using randomized changes in work rate

2021 ◽  
Author(s):  
Uwe Hoffmann ◽  
Felix Faber ◽  
Uwe Drescher ◽  
Jessica Koschate
Keyword(s):  
Time Domain ◽  
Ventilatory Threshold ◽  
Exercise Physiology ◽  
Work Rate ◽  
Steady States ◽  
Binary Sequences ◽  
Impulse Responses ◽  
Test Protocol ◽  
Two Phases ◽  
The Time Domain

Abstract Purpose Kinetics of cardiorespiratory parameters (CRP) in response to work rate (WR) changes are evaluated by pseudo-random binary sequences (PRBS testing). In this study, two algorithms were applied to convert responses from PRBS testing into appropriate impulse responses to predict steady states values and responses to incremental increases in exercise intensity. Methods 13 individuals (age: 41 ± 9 years, BMI: 23.8 ± 3.7 kg m−2), completing an exercise test protocol, comprising a section of randomized changes of 30 W and 80 W (PRBS), two phases of constant WR at 30 W and 80 W and incremental WR until subjective fatigue, were included in the analysis. Ventilation ($$\dot{V}_{{\text{E}}}$$ V ˙ E ), O2 uptake ($$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 ), CO2 output ($$\dot{V}{\text{CO}}_{2}$$ V ˙ CO 2 ) and heart rate (HR) were monitored. Impulse responses were calculated in the time domain and in the frequency domain from the cross-correlations of WR and the respective CRP. Results The algorithm in the time domain allows better prediction for $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 and $$\dot{V}{\text{CO}}_{2}$$ V ˙ CO 2 , whereas for $$\dot{V}_{{\text{E}}}$$ V ˙ E and HR the results were similar for both algorithms. Best predictions were found for $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 and HR with higher (3–4%) 30 W steady states and lower (1–4%) values for 80 W. Tendencies were found in the residuals between predicted and measured data. Conclusion The CRP kinetics, resulting from PRBS testing, are qualified to assess steady states within the applied WR range. Below the ventilatory threshold, $$\dot{V}{\text{O}}_{2}$$ V ˙ O 2 and HR responses to incrementally increasing exercise intensities can be sufficiently predicted.

Time Domain Replica Signal Based Interference Compensation for SP-MIMO/OFDM with Large Delay Spread Channel

2014 ◽  
Vol 5 (4) ◽  
pp. 1-17
Author(s):  
Taichi Sakaue ◽  
Chang-Jun Ahn ◽  
Tatsuya Omori ◽  
Ken-Ya Hashimoto
Keyword(s):  
Mobile Communications ◽  
Time Domain ◽  
Delay Spread ◽  
Impulse Responses ◽  
Channel State ◽  
Large Delay ◽  
Guard Interval ◽  
Interference Compensation ◽  
Mimo Ofdm ◽  
The Time Domain

In mobile communications, MIMO-OFDM transmission performance suffers severe degradation caused by the large delay spread channel greater than guard interval (GI). This is because the excess delay results in considerable inter-symbol interference (ISI) between adjacent symbols and inter-carrier-interference (ICI) among subcarrier in the same symbol. In case of scattered pilot (SP), the interference of pilot signals causes the deterioration of channel estimation. To mitigate this problem, in this paper, we propose the interference compensation scheme using the time domain replica signals. We make the time domain replica signals from detected signals and the excess channel impulse responses over GI. After compensation of the time domain replica signals and the received signals, we recalculate the channel state information (CSI) and the CSI is updated. Finally, we carry out the channel compensation with updated CSI for obtaining accurate compensated signals.

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