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Статті в журналах з теми "Zero drift"

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Автор: Grafiati

Опубліковано: 30 травня 2022

Оновлено: 31 травня 2022

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1

Sun, Jun Wei, and Ya Zhang. "Algorithm for Inhibition of Zero Drift." Advanced Materials Research 616-618 (December 2012): 2068–71. http://dx.doi.org/10.4028/www.scientific.net/amr.616-618.2068.

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By elaborating the basic idea of eliminating zero drift with software, derives the algorithm to eliminate three zero drift, and deals with the zero drift sampled signal using MATLAB software program after analyzing the internal features of baseline of zero drift, the slope of the zero drift and step zero drift.

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2

Kolbas, Yu Yu, and M. A. Ivanov. "Improved Algorithm for Mathematical Correction of the Zero Drift of the Zeeman Laser Gyro with Switching Longitudinal Mode of Generation." Herald of the Bauman Moscow State Technical University. Series Instrument Engineering, no. 2 (125) (April 2019): 91–103. http://dx.doi.org/10.18698/0236-3933-2019-2-91-103.

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The paper addresses time and temperature zero drifts in Zeeman laser gyroscope (RLG) operating in the mode of periodic adjustment of RLG to the longitudinal mode of generation with the opposite circular polarization of the light wave. In such a gyroscope, the zero drift can be divided into magnetic and non-magnetic components having different nature and making a significantly different contribution to the final error. Algorithmic methods are proposed for mathematical compensation of RLG zero drift, both with and without using initial calibration. It is shown that the simultaneous use of reproducible dependencies of the magnetic and non-magnetic zero drifts due to RLG temperature changes allows solving the problem of RLG zero drift correction in the optimal way. The correction factors are calculated from the temperature of a Zeeman laser gyro at the moment of activation. At the same time, using the difference between the temperatures of the gyroscope and gyro case, where it is installed, it is possible to determine the temperature of the Zeeman laser gyroscope at the moment of switching on, thereby eliminating the problem of calculating the correction factors when the gyroscope is turned off and then on again. Experimental results for several Zeeman laser gyroscopes with typical values of zero drifts are presented

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3

Wong, Jacob Y., and Mike Schell. "Zero drift NDIR gas sensors." Sensor Review 31, no. 1 (January 25, 2011): 70–77. http://dx.doi.org/10.1108/02602281111099116.

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4

Kajikawa, Hiroaki, and Tokihiko Kobata. "Different long-term characteristics of hydraulic pressure gauges under constant pressure applications." ACTA IMEKO 8, no. 3 (September 30, 2019): 19. http://dx.doi.org/10.21014/acta_imeko.v8i3.665.

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This article focuses on the long-term drifts of hydraulic pressure gauges, which are constantly subjected to high pressures. A target measurement pressure was consistently applied to pressure gauges for more than two months, and the gauges were occasionally calibrated against a reference pressure balance. The long-term drift has been evaluated based on the variations in calibration values with the elapsed time since the pressure application. We evaluated the long-term drift of three kinds of pressure gauges that are commonly used for calibrations and industrial measurements. The long-term drift differed depending on the type of sensing structure. Although the gauges that had similar sensing structures showed similar drift when the gauges were pressurised due to atmospheric pressure, the amount of the drift depended on each product. In addition, the long-term drift was also affected significantly by the preliminary pressure conditions, even under the same pressure application. Preliminary or ex-post evaluations are necessary for the respective gauges under similar pressure conditions. In practice, the drift of zero-reading is often the main contributory factor of the drift; therefore, the drift can be mitigated by tracing the zero-reading during the pressure applications

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5

Krylov, A. A., and P. S. Kuznetsov. "MEMS gyroscope zero drift elimination at different temperature dynamics." Journal of «Almaz – Antey» Air and Space Defence Corporation, no. 2 (June 30, 2019): 34–39. http://dx.doi.org/10.38013/2542-0542-2019-2-34-39.

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The paper describes the physical causes of zero drift and its dependence on temperature. To reveal the temperature dependence of the drift at different heating dynamics, experiments were carried out with different switching intervals. The correlations between the drift and temperature are studied for different switching intervals at a number of significant time points from the switching. A method of drift compensation at different heating dynamics is proposed, which determines the interval closest to the current temperature dynamics

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6

Poroykov, A. Yu, S. V. Lebedev, R. V. Kontsov, A. A. Sinitsyn, and I. S. Zharenov. "Object orientation measurement system without zero drift." Journal of Physics: Conference Series 1636 (September 2020): 012030. http://dx.doi.org/10.1088/1742-6596/1636/1/012030.

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7

Tian, Yuan, and Jie Luo. "Semiparametric Regression Analysis on the AB Data with Zero-Point Drift." Applied Mechanics and Materials 568-570 (June 2014): 227–32. http://dx.doi.org/10.4028/www.scientific.net/amm.568-570.227.

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To deal with the AB data with zero-point drift, Swanson and Schlamminger have proposed a filter method to remove the drift of any desired polynomial order, and then give the best linear unbiased estimator of the observable, on the condition that the order of drift is known. Since this method directly removes the drift, one can not know the tendency of the systematic error. This paper proposes to construct a semiparametric regression model for the data, and then take the penalized least squares method to estimate the observable and the drift tendency simultaneously. Simulation analysis shows that the semiparametric method can reach the same accuracy of the filter method, and the estimation of the drift fits well with its actual value.

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8

Al-Tamimi, Yahia Z., Adel Helmy, Seb Bavetta, and Stephen J. Price. "ASSESSMENT OF ZERO DRIFT IN THE CODMAN INTRACRANIAL PRESSURE MONITOR." Neurosurgery 64, no. 1 (January 1, 2009): 94–99. http://dx.doi.org/10.1227/01.neu.0000328392.98602.5a.

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Abstract OBJECTIVE Intraparenchymal monitoring devices play an important role in the daily management of head injury and other critically ill neurosurgical patients. Although zero drift data exist for the Camino system (Camino Laboratories, San Diego, CA), only in vitro data exist for the Codman system (Codman and Shurtleff, Inc., Raynham, MA). The aim of this study was to assess the extent of zero drift for the Codman intracranial pressure (ICP) monitor in patients being monitored in 2 neurointensive care units. METHODS This was a prospective study conducted at 2 neurointensive care units. Eighty-eight patients who required ICP monitoring and who presented to the 2 neurosurgical departments, Center 1 (n = 48) and Center 2 (n = 40), were recruited for participation. The duration of ICP monitoring was noted, as was the resultant pressure reading in normal saline on removing the ICP monitor (zero drift). RESULTS The median absolute zero drift for the group was 2.0 mm Hg (interquartile range, 1–3 mm Hg). The median time in situ was 108 hours (interquartile range, 69–201 hours). There was a positive correlation between the drift and time of the probe spent in situ (Spearman's correlation coefficient = 0.342; P = 0.001). Of the readings, 20 and 2% showed a drift greater than 5 and 10 mm Hg in magnitude, respectively. CONCLUSION These data demonstrate that a small amount of zero drift exists in ICP monitors and that this drift increases with time. The wide range in the data demonstrates that some drift readings are quite excessive. This reinforces the school of thought that, although ICP readings contribute significantly to the management of neurosurgical patients, they should be interpreted carefully and in conjunction with clinical and radiological assessment of patients.

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9

Magdon-Ismail, Malik, Amir F. Atiya, Amrit Pratap, and Yaser S. Abu-Mostafa. "On the maximum drawdown of a Brownian motion." Journal of Applied Probability 41, no. 01 (March 2004): 147–61. http://dx.doi.org/10.1017/s0021900200014108.

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The maximum drawdown at time T of a random process on [0,T] can be defined informally as the largest drop from a peak to a trough. In this paper, we investigate the behaviour of this statistic for a Brownian motion with drift. In particular, we give an infinite series representation of its distribution and consider its expected value. When the drift is zero, we give an analytic expression for the expected value, and for nonzero drift, we give an infinite series representation. For all cases, we compute the limiting (T → ∞) behaviour, which can be logarithmic (for positive drift), square root (for zero drift) or linear (for negative drift).

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10

Magdon-Ismail, Malik, Amir F. Atiya, Amrit Pratap, and Yaser S. Abu-Mostafa. "On the maximum drawdown of a Brownian motion." Journal of Applied Probability 41, no. 1 (March 2004): 147–61. http://dx.doi.org/10.1239/jap/1077134674.

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The maximum drawdown at time T of a random process on [0,T] can be defined informally as the largest drop from a peak to a trough. In this paper, we investigate the behaviour of this statistic for a Brownian motion with drift. In particular, we give an infinite series representation of its distribution and consider its expected value. When the drift is zero, we give an analytic expression for the expected value, and for nonzero drift, we give an infinite series representation. For all cases, we compute the limiting (T → ∞) behaviour, which can be logarithmic (for positive drift), square root (for zero drift) or linear (for negative drift).

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11

Atkinson, R. A., and Peter Clifford. "The escape probability for integrated Brownian motion with non-zero drift." Journal of Applied Probability 31, no. 4 (December 1994): 921–29. http://dx.doi.org/10.2307/3215317.

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We consider the two-dimensional process {X(t), V(t)} where {V(t)} is Brownian motion with drift, and {X(t)} is its integral. In this note we derive the joint density function of T and V(T) where T is the time at which the process {X(t)} first returns to its initial value. A series expansion of the marginal density of T is given in the zero-drift case. When V(0) and the drift are both positive there is a positive probability that {Χ (t)} never returns to its initial value. We show how this probability grows for small drift. Finally, using the Kontorovich–Lebedev transform pair we obtain the escape probability explicitly for arbitrary values of the drift parameter.

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12

Atkinson, R. A., and Peter Clifford. "The escape probability for integrated Brownian motion with non-zero drift." Journal of Applied Probability 31, no. 04 (December 1994): 921–29. http://dx.doi.org/10.1017/s0021900200099459.

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We consider the two-dimensional process {X(t), V(t)} where {V(t)} is Brownian motion with drift, and {X(t)} is its integral. In this note we derive the joint density function of T and V(T) where T is the time at which the process {X(t)} first returns to its initial value. A series expansion of the marginal density of T is given in the zero-drift case. When V(0) and the drift are both positive there is a positive probability that {Χ (t)} never returns to its initial value. We show how this probability grows for small drift. Finally, using the Kontorovich–Lebedev transform pair we obtain the escape probability explicitly for arbitrary values of the drift parameter.

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13

KRASIŃSKI, ANDRZEJ, and KRZYSZTOF BOLEJKO. "EXACT INHOMOGENEOUS MODELS AND THE DRIFT OF LIGHT RAYS INDUCED BY NONSYMMETRIC FLOW OF THE COSMIC MEDIUM." International Journal of Modern Physics D 22, no. 06 (April 28, 2013): 1330013. http://dx.doi.org/10.1142/s0218271813300139.

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After introducing the Szekeres and Lemaître–Tolman cosmological models, the real-time cosmology program is briefly mentioned. Then, a few widespread misconceptions about the cosmological models are pointed out and corrected. Investigation of null geodesic equations in the Szekeres models shows that observers in favorable positions would see galaxies drift across the sky at a rate of up to 10-6 arc s per year. Such a drift would be possible to measure using devices that are under construction; the required time of monitoring would be ≈10 years. This effect is zero in the FLRW models, so it provides a measure of inhomogeneity of the Universe. In the Szekeres models, the condition for zero drift is zero shear. But in the shearfree normal models, the condition for zero drift is that, in the comoving coordinates, the time dependence of the metric completely factors out.

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14

Heeley, Andrew D., Matthew J. Hobbs, and Jon R. Willmott. "Zero Drift Infrared Radiation Thermometer Using Chopper Stabilised Pre-Amplifier." Applied Sciences 10, no. 14 (July 15, 2020): 4843. http://dx.doi.org/10.3390/app10144843.

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A zero-drift, mid–wave infrared (MWIR) thermometer constructed using a chopper stabilised operational amplifier (op-amp) was compared against an identical thermometer that utilised a precision op-amp. The chopper stabilised op-amp resulted in a zero-drift infrared radiation thermometer (IRT) with approximately 75% lower offset voltage, 50% lower voltage noise and less susceptibility to perturbation by external sources. This was in comparison to the precision op-amp IRT when blanked by a cover at ambient temperature. Significantly, the zero-drift IRT demonstrated improved linearity for the measurement of target temperatures between 20 °C and 70 °C compared to the precision IRT. This eases the IRT calibration procedure, leading to improvement in the tolerance of the temperature measurement of such low target temperatures. The zero-drift IRT was demonstrated to measure a target temperature of 40 °C with a reduction in the root mean square (RMS) noise from 5 K to 1 K compared to the precision IRT.

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15

Xia, Weiqiang, Shangchun Fan, Weiwei Xing, Tiehua Ma, Jing Zu, and Jinbiao Fan. "Restraining zero drift in an ultrahigh-gimpact environment." Measurement Science and Technology 23, no. 3 (February 8, 2012): 035108. http://dx.doi.org/10.1088/0957-0233/23/3/035108.

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16

Magalas, Leszek B., and A. Piłat. "Zero-Point Drift in Low-Frequency Mechanical Spectroscopy." Solid State Phenomena 115 (August 2006): 285–92. http://dx.doi.org/10.4028/www.scientific.net/ssp.115.285.

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The concept of the ‘zero-point drift’, ZPD, is introduced and analyzed on the basis of mechanical loss measurements carried out in a low-frequency mechanical spectrometer – inverted torsion pendulum. It is demonstrated that the ZPD, which modifies damped harmonic oscillations leads to false values of the logarithmic decrement computed from several widely accepted algorithms.

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17

Shi, Yonglei, Liqing Fang, Rongxiang Li, Deqing Guo, Sa Zhang, and Qiongjie Tang. "Processing method of acceleration signal with zero drift." Journal of Physics: Conference Series 1952, no. 3 (June 1, 2021): 032061. http://dx.doi.org/10.1088/1742-6596/1952/3/032061.

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18

He, Yuping, and Shijie Zhang. "SMC-Based Synchronization of Multiple Inertial Measurement Units with Application to Attitude Tracking Control." Mathematical Problems in Engineering 2021 (February 17, 2021): 1–9. http://dx.doi.org/10.1155/2021/6637641.

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In this paper, the attitude control of aircraft with multiple inertial measurement units under the influence of unknown gyro zero drift and external disturbance is studied. First of all, the observers are designed to estimate the zero drift biases based on the consensus algorithm. The angular velocity used for aircraft control is obtained by compensating the biases. Then, considering the external disturbance in the aircraft motion, this paper introduces a super-twisting sliding-mode algorithm to design the observer in order to compensate the disturbance. In addition, based on the proposed observers, a controller is designed to realize attitude control of the aircraft with the gyro zero drift and the external disturbance. Finally, the simulation results are given to verify the effectiveness of the proposed control law.

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19

Fu, Qiang, Xin-Peng Di, Wei-Ping Chen, Liang Yin, and Xiao-Wei Liu. "A temperature characteristic research and compensation design for micro-machined gyroscope." Modern Physics Letters B 31, no. 06 (February 28, 2017): 1750064. http://dx.doi.org/10.1142/s0217984917500646.

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The all temperature range stability is the most important technology of MEMS angular velocity sensor according to the principle of capacity detecting. The correlation between driven force and zero-point of sensor is summarized according to the temperature characteristic of the air-damping and resonant frequency of sensor header. A constant trans-conductance high-linearity amplifier is designed to realize the low phase-drift and low amplitude-drift interface circuit at all-temperature range. The chip is fabricated in a standard 0.5 [Formula: see text] CMOS process. Compensation achieved by driven force to zero-point drift caused by the stiffness of physical construction and air-damping is adopted. Moreover, the driven force can be obtained from the drive-circuit to avoid the complex sampling. The test result shows that the zero-point drift is lower than 30[Formula: see text]/h (1-sigma) at the temperature range from −40[Formula: see text]C to 60[Formula: see text]C after three-order compensation made by driven force.

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20

Wang, Xing, Lin Hua Piao, and Quan Gang Yu. "Research on Nozzle Array Structure Fluidic Gyroscope Zero Temperature Compensation." Advanced Materials Research 542-543 (June 2012): 631–34. http://dx.doi.org/10.4028/www.scientific.net/amr.542-543.631.

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The nozzle array structure fluidic gyroscope’s zero temperature compensation was researched. The fluidic gyroscope’s temperature characteristic was analyzed in the sensitive element and two zero temperature compensation methods were compared. Then, the software compensation method was used, which based on the Single chip microcomputer technology and realized temperature compensation for the gyroscope output signal. The results show that after the compensation, the gyroscope’s zero drift decreases from ≤1.3mV/°C to ≤0.1mV/°C and operating temperature range increases from normal temperature to -40°C~+60°C. Therefore, the fluidic gyroscope has the advantage of low zero drift and width operating temperature range after the zero temperature compensation, which provides the convenience for the production and application.

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21

Ahrens, T., JC Penick, and MK Tucker. "Frequency requirements for zeroing transducers in hemodynamic monitoring." American Journal of Critical Care 4, no. 6 (November 1, 1995): 466–71. http://dx.doi.org/10.4037/ajcc1995.4.6.466.

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BACKGROUND: Accurate hemodynamic monitoring information can be obtained only if the transducer/amplifier system is used correctly. One major component of correct use is zeroing the transducer to provide a relative reference point on which to measure hemodynamic pressures. However, nursing requirements for frequency of zeroing are inconsistent. In addition, the concepts of leveling and zeroing are frequently confused. OBJECTIVE: To determine whether transducers drift from zero (+/- 2 mm Hg), and if they do not drift from zero, how long they hold a zero value. METHODS: The study, conducted in four midwestern hospitals, was carried out in two parts: an initial 10-day bench test of 50 transducers and an evaluation of 388 transducers attached to patients for 1 to 5 days. Transducers were monitored over time after being consistently leveled. RESULTS: Bench testing indicated that 100% of transducers did not drift +/- 2 mm Hg from zero during the study period. In the clinical study, only 1.3% of transducers drifted from zero. Five transducers drifted +/- 2 mm Hg from zero, with a range of -5 to 3 mm Hg. CONCLUSIONS: We conclude that transducers used for hemodynamic monitoring require zeroing only on initial setup and disconnection from the amplifier.

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22

Lerche, Hans Rudolf, and Ilse Maahs. "Sequential Detection of Drift Change for Brownian Motion with Unknown Sign." gmj 15, no. 4 (December 2008): 713–30. http://dx.doi.org/10.1515/gmj.2008.713.

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Abstract We study tests of power one for the following change-point problem. Suppose one observes a process 𝑊 which is either a Brownian motion without drift or a Brownian motion that has zero drift up to a random time τ after which with equal probability the drift becomes either θ or –θ, where the value of θ > 0 is known. The distribution of τ is also assumed to be known. We search for a stopping time 𝑇* that minimizes an appropriate Bayes risk and give a solution that is asymptotically optimal, when the cost of observation tends to zero.

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23

Dinh, Trieu-Vuong, In-Young Choi, Byeong-Gyu Park, Jee-Hyun Lee, In-Young Kim, Han-Nui Gil, Sang-Woo Lee, and Jo-Chun Kim. "Development of a Negligible Zero-Drift NDIR Analyzer for Measuring NH3 Emitted from an Urban Household Solid Waste Incinerator." Atmosphere 12, no. 7 (June 30, 2021): 858. http://dx.doi.org/10.3390/atmos12070858.

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An analyzer for measuring NH3 emitted from a combustion process has been developed based on a simple non-dispersive infrared (NDIR) technique because of its cost-effective benefit. The weakness of the NDIR analyzer due to interference and zero-drift has been overcome. A least-interfering bandpass filter (BPF) was found and manufactured to compensate for the interfering effects of gases emitted from a combustion process (e.g., CO, NOx, SO2, CO2, H2O, HCl, formaldehyde, acetaldehyde and toluene). It was found that there was no significant interference in the least-interfering BPF with respect to gases of concern. Measurement errors by the analyzer were less than 2.5% in a range of 1 to 10 ppmv of NH3 compared to a standard method when the compound was measured in complicated mixing gases. For the zero-drift, using BPFs with identical center wavelength with respect to different incident infrared intensity was found to help minimize the zero-drift of the NDIR analyzer. As a result, the analyzer could cut approximately 19% of zero-drift caused by the aging effect of both IR source and detector. It suggests that the analyzer could be applied for measuring NH3 emitted from combustion processes with good accuracy and reproducibility.

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24

Lü Hang, 吕航, 廖宁放 Liao Ningfang, 吴文敏 Wu Wenmin, 曹玮亮 Cao Weiliang, 王佳佳 Wang Jiajia, and 程灏波 Cheng Haobo. "Zero-Order Drift of Interferograms in Ultraviolet Imaging Spectrometer." Acta Optica Sinica 36, no. 9 (2016): 0911003. http://dx.doi.org/10.3788/aos201636.0911003.

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25

Kvasnikov, Volodymyr, and Anatolij Perederko. "Removal of temperature drift of zero of piezoelectric accelerometer." Technology audit and production reserves 1, no. 1(51) (December 24, 2019): 41–44. http://dx.doi.org/10.15587/2312-8372.2020.199068.

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26

du Toit, J., G. Peskir, and A. N. Shiryaev. "Predicting the last zero of Brownian motion with drift." Stochastics 80, no. 2-3 (April 2008): 229–45. http://dx.doi.org/10.1080/17442500701840950.

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27

Korshunov, D. A. "Moments for stationary Markov chains with asymptotically zero drift." Siberian Mathematical Journal 52, no. 4 (July 2011): 655–64. http://dx.doi.org/10.1134/s0037446611040100.

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28

Ricklefs, Robert E. "A comment on Hubbell's zero-sum ecological drift model." Oikos 100, no. 1 (January 2003): 185–92. http://dx.doi.org/10.1034/j.1600-0706.2003.12018.x.

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29

Teng, Teng, Zhi Hua Zhao, and Tao Tao. "Zero Drift Automatic Suppression Technology for Non-Inertia Integrating Circuit Based on C8051F350 MCU." Applied Mechanics and Materials 392 (September 2013): 687–92. http://dx.doi.org/10.4028/www.scientific.net/amm.392.687.

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The non-inertia integration circuit is a basic segment for the reduction of DC or low-frequency small signals. Whether the circuit can work normally or not depends on zero drift. Through a detailed study of a certain non-inertia integrating circuit, this paper has proposed a kind of zero drift technology based on C8051F350 to automatically suppress the drift voltage from the input of the operational amplifier by injecting the suppression signals into the input of the amplifier directly. This technology is designed to ensure that the integrating circuit can work accurately for more than 10 seconds. The experiments have shown that the technology is effective and feasible.

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30

Tao, Huan Qi, and Heng Zhang. "Application Research of Solving Random Drift Based on Dynamic Tracking in the Detection System." Advanced Materials Research 647 (January 2013): 833–37. http://dx.doi.org/10.4028/www.scientific.net/amr.647.833.

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To eliminate the zero drift of the detection system, In this paper, a method of dynamic real-time tracking component parameter values are discussed to solve the temperature drift and time drift problems. That in the original basis, starting only from the system hardware, an increase of only two precision standard resistor, thus effectively solving the system of drift and time drift problems. This method greatly improves system stability and anti-jamming capability of work, but also improves the interchangeability between components.

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31

POKHOTELOV, O. A., O. G. ONISHCHENKO, P. K. SHUKLA, and L. STENFLO. "Drift–Alfvén vortices in dusty plasmas with non-zero ion-temperature effects." Journal of Plasma Physics 64, no. 4 (October 2000): 319–32. http://dx.doi.org/10.1017/s0022377800008643.

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Reduced two-fluid equations governing the nonlinear dynamics of drift–Alfvén waves in dusty plasmas with non-zero ion temperature are derived. In the linear limit, we find a dispersion relation that shows the coupling between the ion-drift–Shukla–Varma mode, and electron-drift (magnetostatic) and (inertial or kinetic) Alfvén waves due to the finite collisionless electron skin depth or Larmorradius corrections. In contrast to the case of an electron–ion plasma, when the nonlinear drift–Alfvén vortices are weakly localized, i.e. decrease at infinity as r−1, the presence of the charged dust grains makes exponential localization possible. The physical meaning of such a localization is connected with the fact that charged massive dust granules provide an additional screening that results in stronger localization of the vortex. In several intermediate-β plasmas with 1 [Gt ] β [Gt ] me/mi (me,i is the electron or ion mass), the localization length approaches a minimum value when the vortex velocity is of the order of the ion diamagnetic drift. It then reaches the value ρiδ−1/4d where ρi is the ion Larmor radius and δd is the ratio of the dust to ion densities multiplied by the dust charge number Zd. In the case of very low plasma pressure, β [Lt ] me/mi, the vortex is localized with typical scale (λeρi)1/2δ−1/4d where λe is the electron skin depth. Our investigation can thus predict the velocities of coherent nonlinear structures in space plasmas.

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32

BOCHI, JAIRO, and ANDRÉS NAVAS. "A geometric path from zero Lyapunov exponents to rotation cocycles." Ergodic Theory and Dynamical Systems 35, no. 2 (August 20, 2013): 374–402. http://dx.doi.org/10.1017/etds.2013.58.

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AbstractWe consider cocycles of isometries on spaces of non-positive curvature $H$. We show that the supremum of the drift over all invariant ergodic probability measures equals the infimum of the displacements of continuous sections under the cocycle dynamics. In particular, if a cocycle has uniform sublinear drift, then there are almost invariant sections, that is, sections that move arbitrarily little under the cocycle dynamics. If, in addition, $H$ is a symmetric space, then we show that almost invariant sections can be made invariant by perturbing the cocycle.

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33

Kuznetsov, A. A., and E. P. Kontar. "First imaging spectroscopy observations of solar drift pair bursts." Astronomy & Astrophysics 631 (November 2019): L7. http://dx.doi.org/10.1051/0004-6361/201936447.

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Drift pairs are an unusual and puzzling type of fine structure sometimes observed in dynamic spectra of solar radio emission. They appear as two identical short narrowband drifting stripes separated in time; both positive and negative frequency drifts are observed. Currently, due to the lack of imaging observations, there is no satisfactory explanation for this phenomenon. Using the Low Frequency Array (LOFAR), we report unique observations of a cluster of drift pair bursts in the frequency range of 30−70 MHz made on 12 July 2017. Spectral imaging capabilities of the instrument have allowed us for the first time to resolve the temporal and frequency evolution of the source locations and sizes at a fixed frequency and along the drifting pair components. Sources of two components of a drift pair have been imaged and found to propagate in the same direction along nearly the same trajectories. Motion of the second component source is seen to be delayed in time with respect to that of the first one. The source trajectories can be complicated and non-radial; positive and negative frequency drifts correspond to opposite propagation directions. The drift pair bursts with positive and negative frequency drifts, as well as the associated broadband type-III-like bursts, are produced in the same regions. The visible source velocities are variable from zero to a few 104 (up to ∼105) km s−1, which often exceeds the velocities inferred from the drift rate (∼104 km s−1). The visible source sizes are of about 10′−18′; they are more compact than typical type III sources at the same frequencies. The existing models of drift pair bursts cannot adequately explain the observed features. We discuss the key issues that need to be addressed, and in particular the anisotropic scattering of the radio waves. The broadband bursts observed simultaneously with the drift pairs differ in some aspects from common type III bursts and may represent a separate type of emission.

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34

Chen, Wei Cao, Guo Wei Gao, Juan Wang, Li Li Liu, and Xi Lin Li. "The Study of the MEMS Gyro Zero Drift Signal Based on the Adaptive Kalman Filter." Key Engineering Materials 500 (January 2012): 635–39. http://dx.doi.org/10.4028/www.scientific.net/kem.500.635.

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The random noise is an important factor that affects the precision of the MEMS gyroscope. Based on the time-series analysis method, the AR model of the MEMS gyro drift signal is established. Then the adaptive Kalman filter is used to filter the drift signal. Comparison the original signal and the signal filtered by the adaptive Kalman filter, we found that the adaptive Kalman filter has the good filtering effect in the processing the zero drift signal of the MEMS gyro.

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35

Zhang, Wei, and Yuan. "Novel Drift Reduction Methods in Foot-Mounted PDR System." Sensors 19, no. 18 (September 13, 2019): 3962. http://dx.doi.org/10.3390/s19183962.

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The zero-velocity update (ZUPT)-aided extended Kalman filter (EKF) is commonly used in the traditional inertial navigation system (INS)-based foot-mounted pedestrian dead reckoning (PDR) system, which can effectively suppress the error growth of the inertial-based pedestrian navigation systems. However, in the realistic test, the system still often suffers from drift, which is commonly caused by two reasons: failed detection of the stationary phase in the dynamic pedestrian gait and heading drift, which is a poorly observable variable of the ZUPT method. In this paper, firstly, in order to improve the initial heading alignment accuracy, a novel method to calibrate the PDR system’s initial absolute heading is proposed which is based on the geometric method. By using a calibration line rather than only using the heading of the starting point, the method can calibrate the initial heading of the PDR system more accurately. Secondly, for the problem of failed detection of the stationary phase in the dynamic pedestrian gait, a novel stationary phase detection method is proposed, which is based on foot motion periodicity rather than the threshold comparison principle in the traditional method. In an experiment, we found that the zero-speed state points always occur around the minimum value of the stationary detector in each gait cycle. By taking the minimum value in each gait cycle as the zero-speed state point, it can effectively reduce the failed detection of the zero-speed interval. At last, in order to reduce the heading drifts during walking over time, a new motion constraint method is exploited based on the range constraint principle. During pedestrian walking, the distance between the foot position estimates of the current moment and the previous stationary period is within the maximum stride length. Once the distance is greater than the maximum stride length, the constraint method is used to confine the current estimated foot position to the sphere of the maximum stride length relative to the previous stationary foot position. Finally, the effectiveness of all proposed methods is verified by the experiments.

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36

Georgiou, Nicholas, Mikhail V. Menshikov, Aleksandar Mijatović, and Andrew R. Wade. "Anomalous recurrence properties of many-dimensional zero-drift random walks." Advances in Applied Probability 48, A (July 2016): 99–118. http://dx.doi.org/10.1017/apr.2016.44.

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AbstractFamously, a d-dimensional, spatially homogeneous random walk whose increments are nondegenerate, have finite second moments, and have zero mean is recurrent if d∈{1,2}, but transient if d≥3. Once spatial homogeneity is relaxed, this is no longer true. We study a family of zero-drift spatially nonhomogeneous random walks (Markov processes) whose increment covariance matrix is asymptotically constant along rays from the origin, and which, in any ambient dimension d≥2, can be adjusted so that the walk is either transient or recurrent. Natural examples are provided by random walks whose increments are supported on ellipsoids that are symmetric about the ray from the origin through the walk's current position; these elliptic random walks generalize the classical homogeneous Pearson‒Rayleigh walk (the spherical case). Our proof of the recurrence classification is based on fundamental work of Lamperti.

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37

Denisov, Denis, Dmitry Korshunov, and Vitali Wachtel. "Renewal theory for transient Markov chains with asymptotically zero drift." Transactions of the American Mathematical Society 373, no. 10 (August 6, 2020): 7253–86. http://dx.doi.org/10.1090/tran/8167.

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38

Cerf, Raphaël, and Sana Louhichi. "The Initial Drift of a 2D Droplet at Zero Temperature." Probability Theory and Related Fields 137, no. 3-4 (June 21, 2006): 379–428. http://dx.doi.org/10.1007/s00440-006-0007-4.

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39

Åkerstedt, Hans O. "Drift-kinetic stability analysis of z–pinches." Journal of Plasma Physics 41, no. 1 (February 1989): 45–59. http://dx.doi.org/10.1017/s0022377800013647.

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From the Vlasov-fluid model, a set of approximate stability equations describing the stability of a cylindrically symmetric z–pinch is derived. The equations are derived in the limit of small gyroradius and include kinetic effects such as finite Larmor radius, particle drifts and resonant particles. In the limit of zero Larmor radius and short wavelengths, we apply the equations to the internal m = 0 and m = 1 modes. If the drift term mωD + kVD is neglected in the resonant denominators, we find stability criteria that are more optimistic than the corresponding stability criteria for perpendicular MHD. The neglect of the drift term is, however, not justified for the m = 1 mode, where mωD needs to be retained in order to preserve the property that this approximate model should have the same point of marginal stability as the exact Vlasov-fluid model. Retaining the drift terms, growth rates have been calculated for the m = 1 mode, for a constant-current-density equilibrium and for the Bennett equilibrium. For the Bennett profile, we obtain, when compared with perpendicular MHD, a substantial reduction in growth rate γ/γMHD ≈ 0·2.

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40

Kapoula, Z., D. A. Robinson, and L. M. Optican. "Visually induced cross-axis postsaccadic eye drift." Journal of Neurophysiology 69, no. 4 (April 1, 1993): 1031–43. http://dx.doi.org/10.1152/jn.1993.69.4.1031.

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1. It has been previously shown that, if a visual pattern is transiently moved just after every saccade, it is possible to induce horizontal, postsaccadic, ocular drift after horizontal saccades that persists in the dark. In this study we show that horizontal ocular drift can also be created after vertical saccades. Five human subjects viewed binocularly the interior of a full-field hemisphere filled with a random-dot pattern. They were encouraged to make frequent vertical saccades. During training, eye movements were recorded by the electrooculogram. A computer detected the end of every saccade and immediately moved the pattern to the left after up saccades and right after down saccades. The motion was exponential, its amplitude was 25% of the vertical component of the antecedent saccade, its time constant was 50 ms. Before and after 2-3 h of training, movements of both eyes were measured by the eye-coil/magnetic-field method while subjects were instructed to make vertical saccades in the dark, in the presence of the movable adapting pattern, and between stationary targets for calibration. 2. After training (approximately 20,000 saccades) all subjects developed a zero-latency, exponential ocular drift to the left after up saccades and to the right after down saccades. The amplitude of the horizontal drift, expressed as a percentage of the vertical component of the preceding saccade, was 2.7% in the dark. This rose to 10.2% in the presence of the movable adapting stimulus. The latter rise is not due to visual following systems but to a zero-latency increase in initial drift velocity. 3. The horizontal drifts were usually unequal between the two eyes, indicating the presence of disconjugate movements. We measured intrasaccadic disconjugate horizontal movements of all subjects. In agreement with studies by others of saccades in the light, we measured a divergence during up saccades (1.3 degrees) and a convergence for down (0.4 degrees), but in this case for spontaneous saccades in the dark. After training, these values increased for saccades in the dark but decreased in the light in the presence of the adapting stimulus. These changes were largely idiosyncratic and statistically significant in only a few subjects. 4. The cross-axis postsaccadic drifts were separated into their conjugate and disconjugate components. The disconjugate components were small and idiosyncratic, and the means were small for saccades in the dark. The only consistent trend was in the presence of the adapting stimulus where up saccades were often followed by convergence.(ABSTRACT TRUNCATED AT 400 WORDS)

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41

Mei, Chuan Zhi, Lin Hua Piao, and Bao Li Zhang. "Study on Fluidic Gyroscope Zero Temperature Compensation Method." Advanced Materials Research 756-759 (September 2013): 4225–28. http://dx.doi.org/10.4028/www.scientific.net/amr.756-759.4225.

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This paper had studied on the zero temperature compensation of fluidic gyroscope based on MEMS thermistor. Through the analysis of temperature characteristics of jet gyro sensitive element, two methods of comparison of zero temperature compensation was compared. Then, introduction of SCM and temperature sensor, to achieve zero temperature compensation for gyro output signal. The experiment shows: after compensation, zero voltage variation gyro reduced from 150mV to 10mV, working temperature range from room temperature to-40°C ~+55 °C. The fluidic gyroscope zero temperature compensated with zero drift is low, wide working temperature range advantages.

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42

Koskinen, Lars-Owe D., and Magnus Olivecrona. "Clinical Experience with the Intraparenchymal Intracranial Pressure Monitoring Codman MicroSensor System." Neurosurgery 56, no. 4 (April 1, 2005): 693–98. http://dx.doi.org/10.1227/01.neu.0000156609.95596.24.

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Abstract OBJECTIVE: Our main objective was to study the reliability of the Codman MicroSensor (CMS), used for intracranial pressure (ICP) measurements, as it is used in a clinical setting. In particular, the drift from zero was studied. METHODS: The investigation is a prospective study of 128 patients with a need for neurointensive care who have been treated for various diseases. The patients received an intraparenchymal CMS device, and the zero drift was measured at explantation of the sensor. In another 22 patients, the ICP was recorded simultaneously from a ventriculostomy and a CMS, and the values were compared. The general data of complications and pitfalls are collected from close to 1000 CMS devices implanted. RESULTS: The CMS was used, on average, 7.2 ± 0.4 days per patient. The total time of ICP measurement was 20,040 hours, resulting in at least 7.2 × 107 measuring values displayed. The drift from zero was 0.9 ± 0.2 mm Hg, and no correlation with duration of use was found (P = 0.9, r = 0.002). There was a good correlation between ICP measured by CMS and by ventriculostomy (P < 0.0001, r = 0.79). The average ICP measured with the ventriculostomy was 18.3 ± 0.3 mm Hg, and with the CMS, it was 19.0 ± 0.2 mm Hg. A few minor hematomas were identified, and no infections directly connected to the device were observed. Some pitfalls in handling and problems during magnetic resonance imaging investigations are discussed. CONCLUSION: In our hands, the CMS device is reliable and easy to use. The ICP recordings are stable over time, and there is only a minor zero drift. The device is today our standard method for ICP measurements.

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43

Okojie, R. S., D. Lukco, V. Nguyen, and E. Savrun. "Temperature Induced Voltage Offset Drifts in Silicon Carbide Pressure Sensors." Additional Conferences (Device Packaging, HiTEC, HiTEN, and CICMT) 2012, HITEC (January 1, 2012): 000099–103. http://dx.doi.org/10.4071/hitec-2012-tp16.

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We report the reduction of transient drifts in the zero pressure offset voltage in silicon carbide (SiC) pressure sensors when operating at 600 °C. The previously observed maximum drift of ± 10 mV of the reference offset voltage at 600 °C was reduced to within ± 5 mV. The offset voltage drifts and bridge resistance changes over time at test temperature are explained in terms of the microstructure and phase changes occurring within the contact metallization, as analyzed by Auger electron spectroscopy and field emission scanning electron microscopy. The results have helped to identify the upper temperature reliable operational limit of this particular metallization scheme to be 605 °C.

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44

Bavetta, Seb, John S. Norris, Michelle Wyatt, John C. Sutcliffe, and Peter J. Hamlyn. "Prospective study of zero drift in fiberoptic pressure monitors used in clinical practice." Journal of Neurosurgery 86, no. 6 (June 1997): 927–30. http://dx.doi.org/10.3171/jns.1997.86.6.0927.

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✓ One hundred and one fiberoptic pressure transducers (59 subdural and 42 ventricular) were studied in 86 patients (some in whom more than one device had been inserted). Only four complications occurred: two transient cerebrospinal fluid leaks after removal and two clinically insignificant intracerebral hematomas. No intracranial infections could be attributed to the devices. Technical problems occurred 23 times, with 11 devices ceasing to function before removal, seven becoming displaced, and five microventricular catheters failing to enter the ventricles. Zero-drift readings were obtained for 83 devices at the time of removal (median 66 hours after insertion, range 2 hours–13 days). There was a clear negative bias in the readings (median −3), with a wide range of values (−12 to +14 mm Hg; interquartile range −6 to −1) that was apparent even in the first 3 days of use. There was no important relationship between zero drift and any recorded variable. It is concluded that zero drift of fiberoptic pressure transducers is a significant problem and that undue reliance should not be placed on intracranial pressure readings from these devices in isolation from other clinical and radiological information.

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45

Zhang, Liqiang, Yu Liu, and Jinglin Sun. "A Hybrid Framework for Mitigating Heading Drift for a Wearable Pedestrian Navigation System through Adaptive Fusion of Inertial and Magnetic Measurements." Applied Sciences 11, no. 4 (February 22, 2021): 1902. http://dx.doi.org/10.3390/app11041902.

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Pedestrian navigation systems could serve as a good supplement for other navigation methods or for extending navigation into areas where other navigation systems are invalid. Due to the accumulation of inertial sensing errors, foot-mounted inertial-sensor-based pedestrian navigation systems (PNSs) suffer from drift, especially heading drift. To mitigate heading drift, considering the complexity of human motion and the environment, we introduce a novel hybrid framework that integrates a foot-state classifier that triggers the zero-velocity update (ZUPT) algorithm, zero-angular-rate update (ZARU) algorithm, and a state lock, a magnetic disturbance detector, a human-motion-classifier-aided adaptive fusion module (AFM) that outputs an adaptive heading error measurement by fusing heuristic and magnetic algorithms rather than simply switching them, and an error-state Kalman filter (ESKF) that estimates the optimal systematic error. The validation datasets include a Vicon loop dataset that spans 324.3 m in a single room for approximately 300 s and challenging walking datasets that cover large indoor and outdoor environments with a total distance of 12.98 km. A total of five different frameworks with different heading drift correction methods, including the proposed framework, were validated on these datasets, which demonstrated that our proposed ZUPT–ZARU–AFM–ESKF-aided PNS outperforms other frameworks and clearly mitigates heading drift.

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46

Gu, Haoyang, Huakun Wang, Qiu Zhai, Weibing Feng, and Jiaxiu Cao. "Study on the Dynamic Responses of a Large Caisson during Wet-Towing Transportation." Water 13, no. 2 (January 7, 2021): 126. http://dx.doi.org/10.3390/w13020126.

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Large caissons are extensively applied as deep-water foundations in marine engineering. In fact, caissons are generally prefabricated and transported to project site by wet towing. Motion responses of large caissons and those occurring during the towing process were investigated, and CO2 emissions under various conditions were calculated. These are all considered to ensure towing safety and environmental protection. The caisson resistance coefficient was simulated via Ansys Fluent software. The effects of towrope length, towing speed, and drift depth on the motion responses of caissons under the combined action of wind and wave were evaluated via Ansys AQWA software. Maximum heave value was dominantly affected by rope length and draft depth, and its fluctuation was highly influenced by towing speed and draft depth. However, all of the above mentioned factors had insignificant influences on pitch response. When towing existed, rope tension was rapidly increased from zero to a constant value that depended on towing speed and drift depth. However, the speed of achieving this stable phase depended on the length of the towrope.

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47

Gu, Haoyang, Huakun Wang, Qiu Zhai, Weibing Feng, and Jiaxiu Cao. "Study on the Dynamic Responses of a Large Caisson during Wet-Towing Transportation." Water 13, no. 2 (January 7, 2021): 126. http://dx.doi.org/10.3390/w13020126.

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Анотація:

Large caissons are extensively applied as deep-water foundations in marine engineering. In fact, caissons are generally prefabricated and transported to project site by wet towing. Motion responses of large caissons and those occurring during the towing process were investigated, and CO2 emissions under various conditions were calculated. These are all considered to ensure towing safety and environmental protection. The caisson resistance coefficient was simulated via Ansys Fluent software. The effects of towrope length, towing speed, and drift depth on the motion responses of caissons under the combined action of wind and wave were evaluated via Ansys AQWA software. Maximum heave value was dominantly affected by rope length and draft depth, and its fluctuation was highly influenced by towing speed and draft depth. However, all of the above mentioned factors had insignificant influences on pitch response. When towing existed, rope tension was rapidly increased from zero to a constant value that depended on towing speed and drift depth. However, the speed of achieving this stable phase depended on the length of the towrope.

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48

Jansons, Kalvis M. "Stochastic Stokes' drift with inertia." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 463, no. 2078 (October 17, 2006): 521–30. http://dx.doi.org/10.1098/rspa.2006.1778.

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We consider both the effect of particle inertia on stochastic Stokes' drift, and also a related process which could be considered as a crude model of stochastic Stokes' drift driven by an eddy diffusivity. In the latter, the stochastic forcing is a stable Ornstein–Uhlenbeck process rather than Brownian motion. We show that the eddy Stokes' drift velocity has a peak at a non-zero value of the correlation time-scale for particles that have the same (limiting) diffusivity. For both of the models considered, this study shows that not only can stochastic Stokes' drift be used to sort particles with different diffusivities, but also it can be used to sort particles of the same diffusivities, but with different particle masses or correlation time-scales. This effect may be important in particle sorting applications.

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49

He, Jianing, and Haibo Wang. "The Analysis of Zero Inventory Drift Variants Based on Simple and General Order-Up-To Policies." International Journal of Applied Metaheuristic Computing 1, no. 3 (July 2010): 37–52. http://dx.doi.org/10.4018/jamc.2010070103.

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In this paper, simple and general Order-Up-To (OUT) models with Minimum Mean Square Error (MMSE) forecast for the AR(1) demand pattern are introduced in the control engineering perspective. Important insights about lead-time misidentification are derived from the analysis of variance discrepancy. By applying the Final Value Theorem (FVI), a final value offset (i.e., inventory drift) is proved to exist and can be measured even though the actual lead-time is known. In this regard, to eliminate the inherent offset and keep the system variances acceptable, two kinds of zero inventory drift variants based on the general OUT model are presented. The analysis of variance amplification suggests lead-times should always be estimated conservatively in variant models. The stability conditions for zero inventory drift variants are evaluated in succession and some valuable attributes of the new variants are illustrated via spreadsheet simulation under the assumption that lead-time misidentification is inevitable.

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50

Singh, Nishant K. "Moffatt-drift-driven large-scale dynamo due to fluctuations with non-zero correlation times." Journal of Fluid Mechanics 798 (June 9, 2016): 696–716. http://dx.doi.org/10.1017/jfm.2016.284.

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We present a theory of large-scale dynamo action in a turbulent flow that has stochastic, zero-mean fluctuations of the ${\it\alpha}$ parameter. Particularly interesting is the possibility of the growth of the mean magnetic field due to Moffatt drift, which is expected to be finite in a statistically anisotropic turbulence. We extend the Kraichnan–Moffatt model to explore effects of finite memory of ${\it\alpha}$ fluctuations, in a spirit similar to that of Sridhar & Singh (Mon. Not. R. Astron. Soc., vol. 445, 2014, pp. 3770–3787). Using the first-order smoothing approximation, we derive a linear integro-differential equation governing the dynamics of the large-scale magnetic field, which is non-perturbative in the ${\it\alpha}$-correlation time ${\it\tau}_{{\it\alpha}}$. We recover earlier results in the exactly solvable white-noise limit where the Moffatt drift does not contribute to the dynamo growth/decay. To study finite-memory effects, we reduce the integro-differential equation to a partial differential equation by assuming that ${\it\tau}_{{\it\alpha}}$ be small but non-zero and the large-scale magnetic field is slowly varying. We derive the dispersion relation and provide an explicit expression for the growth rate as a function of four independent parameters. When ${\it\tau}_{{\it\alpha}}\neq 0$, we find that: (i) in the absence of the Moffatt drift, but with finite Kraichnan diffusivity, only strong ${\it\alpha}$ fluctuations can enable a mean-field dynamo (this is qualitatively similar to the white-noise case); (ii) in the general case when also the Moffatt drift is non-zero, both weak and strong ${\it\alpha}$ fluctuations can lead to a large-scale dynamo; and (iii) there always exists a wavenumber ($k$) cutoff at some large $k$ beyond which the growth rate turns negative, irrespective of weak or strong ${\it\alpha}$ fluctuations. Thus we show that a finite Moffatt drift can always facilitate large-scale dynamo action if sufficiently strong, even in the case of weak ${\it\alpha}$ fluctuations, and the maximum growth occurs at intermediate wavenumbers.

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