Method for Determining the Estimated Timing Uncertainty for Digital Sampling Instruments

2021 ◽  
Author(s):  
Sara DiGregorio ◽  
Keyword(s):  
Rise Time ◽  
Measurement Errors ◽  
Interpolation Method ◽  
Sampling Error ◽  
Sampling Rate ◽  
Department Of Energy ◽  
Time Base ◽  
Percentage Error ◽  
Digital Sampling ◽  
Timing Uncertainty

The overall uncertainty in digital captured data points is often misunderstood in our organization and is typically accepted as only the manufacturer uncertainty specification of the time base clock typically on the order of 10-100 parts per million. The time base clock of digital sampling technologies is critically important to maintain timing control of the internal electronics and to achieve the specified sampling rate of the instrument. The time base clock must remain within the manufacturer specification tolerance throughout the calibration interval to assure accurate performance. However, the time base uncertainty does not adequately account for the additional measurement errors accompanying the capture and evaluation of the time values for any cardinal points of interest when periodically sampling analog waveforms generated by other instruments or Units Under Test (UUTs). The proposed methodology described here details a general approach used to estimate the magnitude of the digital instrument sampling error when capturing analog waveforms based upon the instrument sampling rate, the frequency of a nominally equivalent sinusoidal waveform, as well as, whether the time value of any cardinal points is selected by a ‘Next Point After’ or Interpolation method for our purposes. Finally, the overall estimated timing uncertainty is quantified by arithmetically combining the error contributions for the sampling rate, the cardinal point selection method, and the instrument time base specification. The results of this method aid in selecting the appropriate digital sampling technology based upon waveform rise time requirements and provide general engineering guidance. Since the estimated error is a portion of the sampling timestep interval, the percentage error could be significant based upon the measured rise time. Sandia National Laboratories is a multi-mission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy National Nuclear Security Administration under contract DE-NA0003525.

Comparison of Forced-Choice and Subjective Probability Scales Measuring Behavioral Intentions

2000 ◽  
Vol 86 (1) ◽  
pp. 321-332 ◽  
Author(s):  
Laura T. Flannelly ◽  
Kevin J. Flannelly ◽  
Malcolm S. McLeod
Keyword(s):  
Subjective Probability ◽  
Measurement Errors ◽  
Behavioral Intentions ◽  
Cognitive Theory ◽  
Sampling Error ◽  
Forced Choice ◽  
Practical Application ◽  
Support Theory ◽  
Don't Know Responses ◽  
Source Of Error

Three surveys compared the accuracy of predictions based on forced-choice and subjective probability scales. The latter produced significantly more accurate election predictions and significantly reduced the percentage of undecided, or “Don't Know” responses, compared to forced-choice scales in all three surveys. Analysis indicates subjective probability scales decrease sampling error and confirms there is an inherent source of error in traditional forced-choice questions about voting intentions not attributable to sampling error. The results are discussed with respect to (1) sampling and measurement errors in forced-choice and subjective probability scales measuring behavioral intentions, (2) their practical application, and (3) cognitive theory, especially support theory.

scholarly journals Kriging with Unknown Variance Components for Regional Ionospheric Reconstruction

2016 ◽  
Author(s):  
Ling Huang ◽  
Hongping Zhang ◽  
Peiliang Xu ◽  
Jianghui Geng ◽  
Cheng Wang ◽  
...  
Keyword(s):  
Ordinary Kriging ◽  
Variance Components ◽  
Harmonic Functions ◽  
Measurement Errors ◽  
Spatial Interpolation ◽  
Interpolation Method ◽  
Single Frequency ◽  
Estimation Accuracy ◽  
Spherical Cap ◽  
Unknown Variance

Ionospheric delay has been a critical issue that limits the accuracy of GNSS precise positioning and navigation for single-frequency users, especially in mid- and low-latitude regions where irregularity of ionosphere is often significant. Kriging spatial interpolation techniques have been recently introduced to model the spatial correlation and variability of ionosphere, which intrinsically assume that the ionosphere field is stochastically stationary but does not take the random observational errors into account. In this paper, by treating the spatial statistical information on ionosphere as prior knowledge and based on TEC semivariogram analysis, we use Kriging techniques to spatially interpolate TEC values. By assuming that the stochastic models of both the ionospheric signals and measurement errors are only known up to some unknown factors, we propose a new Kriging spatial interpolation method with unknown variance components for both the signals of ionosphere and TEC measurements. Variance component estimation has been integrated with Kriging to reconstruct regional ionospherical delay. The method has been applied to data from the Crustal Movement Observation Network of China (CMONOC) and compared with the ordinary Kriging and polynomial interpolations with spherical cap harmonic functions, polynomial functions and low-degree spherical harmonic functions. The results have shown that the interpolation accuracy of the new proposed method is better than the ordinary Kriging and polynomial interpolation by about 1.2 TECU and 0.7 TECU, respectively. The root mean squared error of the proposed new Kriging with variance components is within 1.5 TECU and is smaller than those from other methods under comparison by about 1 TECU. When compared with ionospheric grid points, the mean squared error of the proposed method is within 6 TECU and smaller than Kriging, indicating that the proposed method can produce more accurate ionospheric delays and better estimation accuracy.

scholarly journals Quantification of stroke volume in a simulated healthy volunteer model of traumatic haemorrhage; a comparison of two non-invasive monitoring devices using error grid analysis alongside traditional measures of agreement

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0261546
Author(s):  
Sam D. Hutchings ◽  
Jim Watchorn ◽  
Rory McDonald ◽  
Su Jeffreys ◽  
Mark Bates ◽  
...  
Keyword(s):  
Stroke Volume ◽  
Lower Limb ◽  
Measurement Errors ◽  
Dynamic Change ◽  
Traumatic Injury ◽  
Haemodynamic Monitoring ◽  
Percentage Error ◽  
Circulating Blood Volume ◽  
Measures Of Agreement ◽  
Error Grid

Introduction Haemorrhage is a leading cause of death following traumatic injury and the early detection of hypovolaemia is critical to effective management. However, accurate assessment of circulating blood volume is challenging when using traditional vital signs such as blood pressure. We conducted a study to compare the stroke volume (SV) recorded using two devices, trans-thoracic electrical bioimpedance (TEB) and supra-sternal Doppler (SSD), against a reference standard using trans- thoracic echocardiography (TTE). Methods A lower body negative pressure (LBNP) model was used to simulate hypovolaemia and in half of the study sessions lower limb tourniquets were applied as these are common in military practice and can potentially affect some haemodynamic monitoring systems. In order to provide a clinically relevant comparison we constructed an error grid alongside more traditional measures of agreement. Results 21 healthy volunteers aged 18–40 were enrolled and underwent 2 sessions of LBNP, with and without lower limb tourniquets. With respect to absolute SV values Bland Altman analysis showed significant bias in both non-tourniquet and tourniquet strands for TEB (-42.5 / -49.6 ml), rendering further analysis impossible. For SSD bias was minimal but percentage error was unacceptably high (35% / 48%). Degree of agreement for dynamic change in SV, assessed using 4 quadrant plots showed a seemingly acceptable concordance rate for both TEB (86% / 93%) and SSD (90% / 91%). However, when results were plotted on an error grid, constructed based on expert clinical opinion, a significant minority of measurement errors were identified that had potential to lead to moderate or severe patient harm. Conclusion Thoracic bioimpedance and suprasternal Doppler both demonstrated measurement errors that had the potential to lead to clinical harm and caution should be applied in interpreting the results in the detection of early hypovolaemia following traumatic injury.

scholarly journals Study of measurement errors of Cabinet Office opinion survey

Impact ◽  
2021 ◽  
Vol 2021 (2) ◽  
pp. 6-7
Author(s):  
Harumasa Yoshimura
Keyword(s):  
Public Opinion ◽  
Measurement Errors ◽  
Japanese Society ◽  
Social Research ◽  
Sampling Error ◽  
Opinion Survey ◽  
Community Surveys ◽  
Public Opinion Surveys ◽  
Survey Results ◽  
Negative Impacts

Public opinion surveys are important for gauging the feelings and behaviours of societies. However, there is the possibility of error, which means that the data collected may not accurately reflect the thoughts and opinions of society, which can have dangerous repercussions. In order to minimise such error, with a specific focus on the Japanese Government's Cabinet Office public opinion survey, Professor Harumasa Yoshimura, Nara University, Japan, is investigating measurement error and, in doing so, he hopes to more accurately reflect the true opinions of Japanese society. This research involves integrating the different factors that can affect the reliability of survey results and looking at non-sampling error, which refers to human mistakes. Yoshimura is proposing a new style of social research that integrates psychometric research with sociological community surveys and believes this is the key to enhancing the reliability of public opinion surveys. Ultimately, improving the accuracy of public opinion surveys will have far-reaching benefits that include more accurately depicting thoughts and behaviours and therefore improving awareness of Japanese society, as well as preventing the negative impacts that inaccurate opinion survey results can have, including the political utilisation of academic endeavours.

scholarly journals Analasys of two low-cost and robust methods for indoor localisation of mobile robots

2017 ◽  
Vol 30 (3) ◽  
pp. 403-416 ◽  
Author(s):  
Milos Petkovic ◽  
Vladimir Sibinovic ◽  
Dragisa Popovic ◽  
Vladimir Mitic ◽  
Darko Todorovic ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Low Cost ◽  
Sampling Rate ◽  
Cost Effective ◽  
Robust Methods ◽  
Lighting Conditions ◽  
Measuring Devices ◽  
Cost Distance ◽  
Indoor Localisation ◽  
Nelder Mead Algorithm

This paper presents two simple and cost effective indoor localisation methods. The first method uses ceiling-mounted wide-view angle webcam, computer vision and coloured circular markers, placed on the top of a robot. Main drawbacks of this method are lens distortion and sensitivity to lighting conditions. After solving these problems, a high localisation accuracy of ?1cm is achieved at about 5 Hz sampling rate. The second method is a version of trilateration, based on ultrasound time of flight distance measurement. An ultrasonic beacon is placed on a robot while wall detectors are strategically placed to avoid an excessive occlusion. The ZigBee network is used for inter-device synchronisation and for broadcasting measured data. Robot location is determined as a solution to the minimisation of measurement errors. Using Nelder-Mead algorithm and low-cost distance measuring devices, a solid sub 5 cm localisation accuracy is achieved at 10Hz.

Deep-learning based forecasting sampling frequency of biosensors in wireless body area networks

2020 ◽  
Vol 39 (3) ◽  
pp. 3195-3227 ◽  
Author(s):  
Mohammad Mehrani ◽  
Iman Attarzadeh ◽  
Mehdi Hosseinzadeh
Keyword(s):  
Short Term Memory ◽  
Fuzzy Inference ◽  
Interpolation Method ◽  
Spline Interpolation ◽  
Sampling Rate ◽  
Body Area Networks ◽  
Wireless Body Area Networks ◽  
Sampling Frequency ◽  
Body Area ◽  
Inference System

Wireless Body Area Networks (WBANs) have been introduced as a useful way in controlling health status of the monitored patients, during recent years. Each WBAN includes a number of biosensors attached to the patient’s body, collecting his vital sign features and communicating them to the coordinator to make appropriate decisions. Managing energy consumption of biosensors and continuous monitoring of the patients are two main issues in WBANs. Hence, denoting efficient sampling frequency of biosensors is very important in WBANs. In this paper, we propose a scheme which aims at determining and forecasting sampling rate of active biosensors in WBANs. In this regard, from the first round until a certain round, the sampling rate of biosensors would be determined. Accordingly, we introduce our modified Fisher test, develop spline interpolation method and introduce three main parameters. These parameters are information of patient’s activity, patient’s risk and pivot biosensor’s value. Then, by employing mentioned parameters in addition to the introduced statistical and mathematical based strategies, the sampling rate of active biosensors in the next round would be determined at the end of each entire round. By reaching a pre-denoted round, the sampling rate of biosensors would be predicted through forecasting methods. For this purpose, we develop two machine learning based techniques namely Adaptive Neuro Fuzzy Inference System (ANFIS) and Long Short Term Memory (LSTM). For estimation our approaches we simulate them in MATLAB R2018b software. Simulation results demonstrate that our methods can decrease the number of communicated data by 81%, reduce energy expenditure of biosensors by 73% and forecast the sampling rate of biosensors in the future rounds with 97% accuracy and 2.2753 RMSE.

A Combined Interpolation Method for Cross Correlation Based Particle Velocity Measurement

2012 ◽  
Vol 508 ◽  
pp. 67-70
Author(s):  
Gang Yang ◽  
Wei Dong Li ◽  
Yu Tao Wang ◽  
Ming Yu Li
Keyword(s):  
Correlation Function ◽  
Velocity Measurement ◽  
Cross Correlation ◽  
Interpolation Method ◽  
Sampling Rate ◽  
Time Delay Estimation ◽  
Parametric Models ◽  
Center Frequency ◽  
Estimation Accuracy ◽  
Particulate Solids

Cross correlation techniques have been proved to be a valuable tool for online continuous velocity measurement of particulate solids in pneumatic pipelines. In order to reduce computational complexity the sampling frequency is usually kept as low as possible, and the peak in the correlation function is found by interpolating the correlation function. Parabola functions are commonly used as parametric models of the cross correlation function in time delay estimation. However, the parabolic-fit interpolation method introduces a bias at low sampling rate to the center frequency ratio of input signal. In this paper, a combined interpolation method is proposed to improve the estimation accuracy. Experiments are carried out to evaluate the performance of the proposed interpolation method for low sampling rate. The experimental results have been promising and have shown the potential of the proposed method for particle flow velocity measurements.

All that Glitters is Not Gold: Examining the Perils and Obstacles in Collecting Data on the Internet

2005 ◽  
Vol 10 (1) ◽  
pp. 115-130 ◽  
Author(s):  
Cha Yeow Siah
Keyword(s):  
Data Collection ◽  
Measurement Errors ◽  
Research Method ◽  
Sampling Error ◽  
Reliability And Validity ◽  
The Internet ◽  
The Past ◽  
Areas Of Concern ◽  
Conducting Research

AbstractThe speed, ease and cost of conducting an internet-based study has attracted an increasingly large number of researchers to the medium for data collection. The lure of conducting research on the internet warrants heightened awareness of the practical problems one may encounter in the course of design and data collection. Researchers should also be attuned to the various threats of reliability and validity that may affect the quality of their data. This article surveys the past literature and identifies four main areas of concern in internet-based research: (1) sampling error and generalizability; (2) subject fraud; (3) measurement errors resulting from extraneous factors, and (4) the ethics of conducting research on the internet. Before carrying out their research on the internet, researchers should carefully weigh the sometimes hidden costs against the obvious benefits to consider whether the results obtained will be seriously compromised by the problems currently existing with this relatively new medium. However, a more productive approach recognizes that this research method is here to stay and thus greater attention needs to be given to refining and clearing the hurdles that internet-based researchers currently face.

scholarly journals A 1.15 μW 200 kS/s 10-b Monotonic SAR ADC Using Dual On-Chip Calibrations and Accuracy Enhancement Techniques

Sensors ◽  
2018 ◽  
Vol 18 (10) ◽  
pp. 3486
Author(s):  
Jae-Hun Lee ◽  
Dasom Park ◽  
Woojin Cho ◽  
Huu Phan ◽  
Cong Nguyen ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Dynamic Range ◽  
Sampling Error ◽  
Sampling Rate ◽  
Oxide Semiconductor ◽  
Cmos Process ◽  
Calibration Technique ◽  
Accuracy Enhancement ◽  
On Chip ◽  
Comparator Offset

Herein, we present an energy efficient successive-approximation-register (SAR) analog-to-digital converter (ADC) featuring on-chip dual calibration and various accuracy-enhancement techniques. The dual calibration technique is realized in an energy and area-efficient manner for comparator offset calibration (COC) and digital-to-analog converter (DAC) capacitor mismatch calibration. The calibration of common-mode (CM) dependent comparator offset is performed without using separate circuit blocks by reusing the DAC for generating calibration signals. The calibration of the DAC mismatch is efficiently performed by reusing the comparator for delay-based mismatch detection. For accuracy enhancement, we propose new circuit techniques for a comparator, a sampling switch, and a DAC capacitor. An improved dynamic latched comparator is proposed with kick-back suppression and CM dependent offset calibration. An accuracy-enhanced bootstrap sampling switch suppresses the leakage-induced error <180 μV and the sampling error <150 μV. The energy-efficient monotonic switching technique is effectively combined with thermometer coding, which reduces the settling error in the DAC. The ADC is realized using a 0.18 μm complementary metal–oxide–semiconductor (CMOS) process in an area of 0.28 mm2. At the sampling rate fS = 9 kS/s, the proposed ADC achieves a signal-to-noise and distortion ratio (SNDR) of 55.5 dB and a spurious-free dynamic range (SFDR) of 70.6 dB. The proposed dual calibration technique improves the SFDR by 12.7 dB. Consuming 1.15 μW at fS = 200 kS/s, the ADC achieves an SNDR of 55.9 dB and an SFDR of 60.3 dB with a figure-of-merit of 11.4 fJ/conversion-step.

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