Filtering a White-Noise Sequence

2008 ◽  
Keyword(s):  
White Noise ◽  
White Noise Sequence ◽  
Noise Sequence

Effects of neuronal norepinephrine uptake blockade on baroreflex neural and peripheral arc transfer characteristics

2004 ◽  
Vol 286 (6) ◽  
pp. R1110-R1120 ◽  
Author(s):  
Toru Kawada ◽  
Tadayoshi Miyamoto ◽  
Kazunori Uemura ◽  
Koji Kashihara ◽  
Atsunori Kamiya ◽  
...  
Keyword(s):  
Transfer Function ◽  
Sympathetic Nerve ◽  
Neuronal Uptake ◽  
Arterial Baroreflex ◽  
Exogenous Disturbance ◽  
Sympathetic Regulation ◽  
White Noise Sequence ◽  
Noise Sequence ◽  
Normalized Gain ◽  
Sinus Pressure

Neuronal uptake is the most important mechanism by which norepinephrine (NE) is removed from the synaptic clefts at sympathetic nerve terminals. We examined the effects of neuronal NE uptake blockade on the dynamic sympathetic regulation of the arterial baroreflex because dynamic characteristics are important for understanding the system behavior in response to exogenous disturbance. We perturbed intracarotid sinus pressure (CSP) according to a binary white noise sequence in anesthetized rabbits, while recording cardiac sympathetic nerve activity (SNA), arterial pressure (AP), and heart rate (HR). Intravenous administration of desipramine (1 mg/kg) decreased the normalized gain of the neural arc transfer function from CSP to SNA relative to untreated control (1.03 ± 0.09 vs. 0.60 ± 0.08 AU/mmHg, mean ± SE, P < 0.01) but did not affect that of the peripheral arc transfer function from SNA to AP (1.10 ± 0.05 vs. 1.08 ± 0.10 mmHg/AU). The normalized gain of the transfer function from SNA to HR was unaffected (1.01 ± 0.04 vs. 1.09 ± 0.12 beats·min−1·AU−1). Desipramine decreased the natural frequency of the transfer function from SNA to AP by 28.7 ± 7.0% (0.046 ± 0.007 vs. 0.031 ± 0.002 Hz, P < 0.05) and that of the transfer function from SNA to HR by 64.4 ± 2.2% (0.071 ± 0.003 vs. 0.025 ± 0.002 Hz, P < 0.01). In conclusion, neuronal NE uptake blockade by intravenous desipramine administration reduced the total buffering capacity of the arterial baroreflex mainly through its action on the neural arc. The differential effects of neuronal NE uptake blockade on the dynamic AP and HR responses to SNA may provide clues for understanding the complex pathophysiology of cardiovascular diseases associated with neuronal NE uptake deficiency.

Bezold-Jarisch reflex attenuates dynamic gain of baroreflex neural arc

2003 ◽  
Vol 285 (2) ◽  
pp. H833-H840 ◽  
Author(s):  
Koji Kashihara ◽  
Toru Kawada ◽  
Yusuke Yanagiya ◽  
Kazunori Uemura ◽  
Masashi Inagaki ◽  
...  
Keyword(s):  
Transfer Function ◽  
Myocardial Ischemia ◽  
Dynamic Characteristics ◽  
Acute Myocardial Ischemia ◽  
Renal Sympathetic Nerve Activity ◽  
Afferent Nerves ◽  
Before And After ◽  
White Noise Sequence ◽  
Noise Sequence ◽  
Dynamic Gain

Although acute myocardial ischemia or infarction may induce the Bezold-Jarisch (BJ) reflex through the activation of serotonin receptors on vagal afferent nerves, the mechanism by which the BJ reflex modulates the dynamic characteristics of arterial pressure (AP) regulation is unknown. The purpose of this study was to examine the effects of the BJ reflex induced by intravenous phenylbiguanide (PBG) on the dynamic characteristics of the arterial baroreflex. In seven anesthetized rabbits, we perturbed intracarotid sinus pressure (CSP) according to a white noise sequence while renal sympathetic nerve activity (RSNA), AP, and heart rate (HR) were recorded. We estimated the transfer function from CSP to RSNA (neural arc) and from RSNA to AP (peripheral arc) before and after 10 min of intravenous administration of PBG (100 μg · kg–1 · min–1). The intravenous PBG decreased mean AP from 84.5 ± 4.0 to 68.2 ± 4.7 mmHg ( P < 0.01), mean RSNA to 76.2 ± 7.0% ( P < 0.05), and mean HR from 301.6 ± 7.7 to 288.4 ± 9.0 beats/min ( P < 0.01). The intravenous PBG significantly decreased neural arc dynamic gain at 0.01 Hz (1.06 ± 0.08 vs. 0.59 ± 0.17, P < 0.05), whereas it did not affect that of the peripheral arc (1.20 ± 0.12 vs. 1.18 ± 0.41). In six different rabbits without intravenous PBG, the neural arc transfer function did not change between two experimental runs with intervening interval of 10 min, excluding the possibility that the cumulative effects of anesthetics had altered the neural arc transfer function. In conclusion, excessive activation of the BJ reflex during acute myocardial ischemia may exert an adverse effect on AP regulation, not only by sympathetic suppression, but also by attenuating baroreflex dynamic gain.

Time Series Analysis of Pulmonary Tuberculosis Incidence: Forecasting by Applying the Time Series Model

2013 ◽  
Vol 709 ◽  
pp. 819-822 ◽  
Author(s):  
Yin Ping Chen ◽  
Ai Ping Wu ◽  
Cui Ling Wang ◽  
Hai Ying Zhou ◽  
Shu Xiu Feng
Keyword(s):  
Time Series ◽  
Pulmonary Tuberculosis ◽  
Moving Average ◽  
Arima Model ◽  
Autoregressive Integrated Moving Average ◽  
Tuberculosis Incidence ◽  
Short Lead Time ◽  
White Noise Sequence ◽  
Noise Sequence ◽  
Residual Sequence

The main objective of this study is to identify the stochastic autoregressive integrated moving average (ARIMA) model to predict the pulmonary tuberculosis incidence in Qianan. Considering the Box-Jenkins modeling approach, the incidence of pulmonary tuberculosis was collected monthly from 2004 to 2010. The model ARIMA(0,1,1)12 was established finally and the residual sequence was a white noise sequence. Then, this model was used for calculating dengue incidence for the last 6 observations compared with observed data, and performed to predict the monthly incidence in 2011. It is necessary and practical to apply the approach of ARIMA model in fitting time series to predict pulmonary tuberculosis within a short lead time.

Adaptive Two-stage Kalman Filter for SINS/Odometer Integrated Navigation Systems

2016 ◽  
Vol 70 (2) ◽  
pp. 242-261 ◽  
Author(s):  
Hongsong Zhao ◽  
Lingjuan Miao ◽  
Haijun Shao
Keyword(s):  
Kalman Filter ◽  
Navigation System ◽  
Scale Factor ◽  
Navigation Systems ◽  
Integrated Navigation ◽  
Two Stage ◽  
Integrated Navigation System ◽  
White Noise Sequence ◽  
Noise Sequence ◽  
Computation Load

In Strapdown Inertial Navigation System (SINS)/Odometer (OD) integrated navigation systems, OD scale factor errors change with roadways and vehicle loads. In addition, the random noises of gyros and accelerometers tend to vary with time. These factors may cause the Kalman filter to be degraded or even diverge. To address this problem and reduce the computation load, an Adaptive Two-stage Kalman Filter (ATKF) for SINS/OD integrated navigation systems is proposed. In the Two-stage Kalman Filter (TKF), only the innovation in the bias estimator is a white noise sequence with zero-mean while the innovation in the bias-free estimator is not zero-mean. Based on this fact, a novel algorithm for computing adaptive factors is presented. The proposed ATKF is evaluated in a SINS/OD integrated navigation system, and the simulation results show that it is effective in estimating the change of the OD scale factor error and robust to the varying process noises. A real experiment is carried out to further validate the performance of the proposed algorithm.

Integrated Fractional white Noise as an Alternative to Multifractional Brownian Motion

2007 ◽  
Vol 44 (02) ◽  
pp. 393-408 ◽  
Author(s):  
Allan Sly
Keyword(s):  
Stochastic Process ◽  
Brownian Motion ◽  
White Noise ◽  
Gaussian Process ◽  
Discrete Data ◽  
Hölder Exponent ◽  
Scaling Properties ◽  
Multifractional Brownian Motion ◽  
Local Properties

Multifractional Brownian motion is a Gaussian process which has changing scaling properties generated by varying the local Hölder exponent. We show that multifractional Brownian motion is very sensitive to changes in the selected Hölder exponent and has extreme changes in magnitude. We suggest an alternative stochastic process, called integrated fractional white noise, which retains the important local properties but avoids the undesirable oscillations in magnitude. We also show how the Hölder exponent can be estimated locally from discrete data in this model.

Auditory Selective Attention in Cerebral-Palsied Individuals

1985 ◽  
Vol 16 (4) ◽  
pp. 260-266 ◽  
Author(s):  
Lee Ann Laraway
Keyword(s):  
Selective Attention ◽  
White Noise ◽  
Normal Subjects ◽  
Auditory Selective Attention ◽  
Normal Individuals ◽  
Significant Difference

The purpose of this study was to determine whether there is a statistically significant difference between the auditory selective attention abilities of normal and cerebral-palsied individuals. Twenty-three cerebral-palsied and 23 normal subjects between the ages of 5 and 21 were asked to repeat a series of 30 items consisting of from 2 to 4 digits in the presence of intermittent white noise. Results of the study indicate that cerebral-palsied individuals perform significantly poorer than normal individuals when the stimulus is accompanied by noise. Noise was not a significant factor in the performance of the normal subjects regardless of age.

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