Average Measurement Error Research Articles

The Practical Significance of Measurement Error in Pulmonary Function Testing Conducted in Research Settings.

Conventional spirometry produces measurement error by using repeatability criteria (RC) to discard acceptable data and terminating tests early when RC are met. These practices also implicitly assume that there is no variation across maneuvers within each test. This has implications for air pollution regulations that rely on pulmonary function tests to determine adverse effects or set standards. We perform a Monte Carlo simulation of 20,902 tests of forced expiratory volume in 1 second (FEV1), each with eight maneuvers, for an individual with empirically obtained, plausibly normal pulmonary function. Default coefficients of variation for inter‐ and intratest variability (3% and 6%, respectively) are employed. Measurement error is defined as the difference between results from the conventional protocol and an unconstrained, eight‐maneuver alternative. In the default model, average measurement error is shown to be ∼5%. The minimum difference necessary for statistical significance at p < 0.05 for a before/after comparison is shown to be 16%. Meanwhile, the U.S. Environmental Protection Agency has deemed single‐digit percentage decrements in FEV1 sufficient to justify more stringent national ambient air quality standards. Sensitivity analysis reveals that results are insensitive to intertest variability but highly sensitive to intratest variability. Halving the latter to 3% reduces measurement error by 55%. Increasing it to 9% or 12% increases measurement error by 65% or 125%, respectively. Within‐day FEV1 differences ≤5% among normal subjects are believed to be clinically insignificant. Therefore, many differences reported as statistically significant are likely to be artifactual. Reliable data are needed to estimate intratest variability for the general population, subpopulations of interest, and research samples. Sensitive subpopulations (e.g., chronic obstructive pulmonary disease or COPD patients, asthmatics, children) are likely to have higher intratest variability, making it more difficult to derive valid statistical inferences about differences observed after treatment or exposure.

A solid fertilizer and seed application rate measuring system for a seed-fertilizer drill machine

To achieve a precise seeding and fertilization control on a seed-fertilizer drill machine, it is essential to first realize accurate on-line measurement of the application rate for the machine. This study was focused on creating an on-line solid fertilizer and seed application rate measuring system based on the weighing principle for seed-fertilizer drill machines. The invented device consisted of a spring set and a weighing sensor, with its weighing mechanism, accurately measures the application rate of the seed-fertilizer drill machine. A real-time signal processing algorithm based on the low-pass filter, mean filter and adaptive Kalman filter was formulated based on analyzing field test results under various conditions. The developed device (with the on-line signal processing algorithm) was integrated to a commercial seed-fertilizer drill machine widely used on Jiangsu region of China and tested in field operations. The parameters being collected for assessing the performance of this developed system included the cumulative and the dynamic application rates in real time. In the cumulative rate measurement tests, this system was operated at three different seeding and fertilizing rates under two operating speeds of the machine. Obtained results showed that the maximum relative error of the cumulative application rate was 4.88%, and the average error of 2.62% with a standard deviation of 1.7% over about 2.5 ha of operation area. In the dynamic rate measurement performance tests, the device was operated at four combinations of seeding and fertilizing rates under two operation speeds. Under the condition of no seeding and fertilization, the average error of the dynamic application rate measurement was 3.15% with a standard deviation of 1.64% over about 2.2 ha of operation area. The seed-fertilizer drill machine was also tested on a wheat seeding operation, the obtained performance results showed that the application rate measuring system can provide the dynamic and cumulative performance information of the seed-fertilizer drill machine. The fluctuation degree of dynamic application rate can illustrate the dynamic regulation performance of the machine. Obtained results verified that the developed solid fertilizer application rate measuring system could not only used to precisely measure application rate, but also used to provide a needed feedback information for accurately control the application via a closed-loop controller to the machine to achieve a variable rate application.

Accuracy of cup orientation and learning curve of the accelerometer-based portable navigation system for total hip arthroplasty in the supine position

To assess the accuracy of cup orientation and learning curve of the disposable accelerometer-based portable navigation system for total hip arthroplasty (THA) in the supine position. A total of 75 patients who underwent THA through the anterolateral supine approach (ALS) with an accelerometer-based portable navigation system for the supine position (HipAlign®) between July 2017 and October 2018 were analyzed in this study. We compared the intraoperative cup angles using navigation records with the postoperative angles using postoperative computed tomography (CT) data. All patients were categorized into the following groups according to the course of three discrete, sequential operative time periods: 1-25 (initial group), 26-50 (intermediate group), and 51-75 (recent group). We compared the accuracy of cup inclination and anteversion among the three groups. The time required for navigation and the operative time of all patients were measured. The average absolute error in measurement (postoperative CT-navigation record) was 2.6° ± 2.7° (inclination) and 2.8° ± 2.7° (anteversion). There were no significant differences among the three groups. The average time required for navigation and the operative time were 365.1 ± 90.3 s and 76.1 ± 1.6 min, respectively. The required time for HipAlign® navigation and operative time were constant in most patients, except for those of the initial five cases. The accelerometer-based portable navigation system provides good accuracy of cup orientation, has a short learning curve, and requires a minimal surgical time for THA in supine position.

Research on Accurate Positioning of Indoor Objects Based on ROS and 3D Point Cloud

Due to the small environmental limitations of GPS satellite positioning and the complexity of the indoor environment, indoor object location technology has the opportunity to display its talents. Considering that the map constructed by ROS SLAM can only describe the two-dimensional information of the environment, the three-dimensional point cloud image can only describe the independent three-dimensional information of the object. This paper combines the indoor 2D map and the 3D point cloud image information of the object constructed by Gmapping algorithm and proposes a composite coordinate positioning system. The whole positioning experimental data has shown that the average measurement error of the position in the object room is only 4.2cm, and its positioning accuracy is 6.7% higher than that of the common ultrasonic and infrared positioning system[1], and the positioning accuracy of the positioning system based on Bluetooth angle measurement[2] is improved by 20% compared with ultra-wideband[3]. Positioning system increased by 72%. The object positioning error is small and the positioning is accurate.

A three-dimensional reconstruction algorithm for extracting parameters of the banana pseudo-stem

Pseudo-stem diameter of banana is an important phenotype parameter reflecting the crop health and growth. Moreover, it indicates the lodging resistance as an important factor for peasants. For rapid measurement of pseudo-stems diameters, a 3D reconstruction algorithm is proposed. This algorithm consists of pseudo-stem reconstruction, point clouds data fitting, and parameter extraction of a depth image obtained by the red, green, blue-depth (RGB-D) camera by using a Particle Swarm Optimization algorithm. The experimental results show that the average measurement error of the pseudo-stem is 4.06 mm. The average relative measurement error is 2.34%. The mentioned results demonstrate the superior treatment effect of the proposed method.

Qubit Measurement by Multichannel Driving.

We theoretically propose and experimentally implement a method of measuring a qubit by driving it close to the frequency of a dispersively coupled bosonic mode. The separation of the bosonic states corresponding to different qubit states begins essentially immediately at maximum rate, leading to a speedup in the measurement protocol. Also the bosonic mode can be simultaneously driven to optimize measurement speed and fidelity. We experimentally test this measurement protocol using a superconducting qubit coupled to a resonator mode. For a certain measurement time, we observe that the conventional dispersive readout yields close to 100% higher average measurement error than our protocol. Finally, we use an additional resonator drive to leave the resonator state to vacuum if the qubit is in the ground state during the measurement protocol. This suggests that the proposed measurement technique may become useful in unconditionally resetting the resonator to a vacuum state after the measurement pulse.

Contactless Monitoring of Pulse Rate and Eye Movement for Uveal Melanoma Patients Undergoing Radiation Therapy

Ensuring eye immobilization and monitoring vital signs are crucial for uveal melanoma patients undergoing radiation therapy (RT). However, current clinical use of an artificial way to observe eye movement and to assess vital signals relies on the use of contact sensors such as finger probe, which is toilsome and inefficient. In this paper, we integrated the contactless measurement methodology to simultaneously monitor the eye movement and pulse rate of patients. The proposed method was also applied to three recruited patients with uveal melanoma to measure the immobilization of eyeball and verify the accuracy of pulse rate detection. Based on the experimental results, the average error of eyeball measurement was 0.96 ± 0.66 mm (mean ± SD) and the average accuracy of pulse rate detection was 96.67%. The environmental illuminance of 2223.92 lx and 1454.59 lx was required to accurately measure eyeball movement and pulse rate, respectively. The use of camera-based contactless measurement under high-energy RT is feasible and has the potential to improve the current clinically used method.

A New Array Pseudolites Technology for High Precision Indoor Positioning

Global Satellite Navigation System (GNSS) can't provide normal location service in the indoor environment because the signal can be blocked by buildings. The pseudolites system can supplement GNSS, especially in the indoor environments. A new indoor array pseudolites system is introduced, its multi-channel transmitter has an identical clock source. The high-precision Doppler positioning method based on Z-fixed Known Point Initialization (Z-KPI) is developed without ambiguity resolution. Some static and dynamic tests are conducted to evaluate the positioning accuracy of this new method. In the static testing, the average Doppler measurement error is 1x10-5 m/s, which lays the foundation of the high precision velocity measurement, and the average positioning error is 0.02 m in X axis, 0.004 m in Y axis, and the average velocity error is 3.28x10 -5 m/s in X axis, 1.94x10 -5 m/s in Y axis. In the dynamic test, the maximum positioning error is 0.39 m in X axis, 0.34 m in Y axis. Finally, the reason for adopting the Z-fixed KPI algorithm is explained by the horizontal dilution of precision (HDOP), meanwhile, the influence of the known initialization point error on indoor positioning accuracy is analyzed, when a deviation from -1.5 m to 0.9 m is added to the Z-axis of the KPI, the maximum positioning error is 0.311 m in X axis, 0.08 m in Y axis; when the horizontal deviation tolerance of the KPI is set from - 0.5 m to 0.5 m, the maximum horizontal positioning error is less than 0.5 m.

Precision Permittivity Measurement for Low-Loss Thin Planar Materials Using Large Coaxial Probe from 1 to 400 MHz

This paper focuses on the non-destructive dielectric measurement for low-loss planar materials with a thickness of less than 3 mm using a large coaxial probe with an outer diameter of 48 mm. The aperture probe calibration procedure required only to make a measurement of the half-space air and three offset shorts. The reflection coefficient for the thin material is measured using a Keysight E5071C network analyzer from 0.3 MHz to 650 MHz and then converted to a relative dielectric constant, εr and tangent loss, tan δ via closed form capacitance model and lift-off calibration process. Average measurement error of dielectric constant, Δεr is less than 6% from 1 MHz to 400 MHz and the resolution of loss tangent, tan δ measurement is capable of achieving 10−3.

Narrow-seam identification and deviation detection in keyhole deep-penetration TIG welding

A narrow-seam identification algorithm is developed to achieve seam tracking in keyhole deep-penetration tungsten inert gas welding (TIG). The welding images are captured by a high-dynamic-range camera and denoised by a bilateral filter based on a noise model analysis. The arc area is extracted as a fixed region of interest. Then, an improved Otsu algorithm and a parabolic fitting algorithm are used to obtain the centerline of the arc. The seam area is extracted as an adaptive region of interest based on a proposed HOG+LBP algorithm. Thereafter, a continuous single-pixel edge contour is extracted by the canny algorithm, and a proposed contour curvature evaluation method is used to obtain the corresponding pixel coordinates. After testing and analysis, the deviation can be reliably detected with an average measurement error within ± 0.04 mm. As a result, the algorithm proposed in this study can accurately identify the deviation during keyhole deep-penetration TIG welding, and has application prospects in the narrow-seam welding field.

Twisted Dual-Cycle Fiber Optic Bending Loss Characteristics for Strain Measurement.

The intensity-based fiber optic sensor (FOS) head using twisted dual-cycle bending loss is proposed and experimentally demonstrate. The bending loss characteristics depend on the steel wire radius, number, and distance. To determine the effects of these parameters, two samples in each of seven configuration cases of the proposed FOS head were bonded to fiber reinforced plastics coupons, and tensile and flexural strain tests were repeated five times for each coupon. The bending loss of the manufactured FOS heads was measured and converted to the tensile and flexural strain as a function of configuration cases. The measurement range, sensitivity, and average measurement errors of the tensile load and flexural strain were 4.5 kN and 1760 με, 0.70 to 3.99 dB/kN and 0.930 to 6.554 dB/mm, and 57.7 N, and 42.6 με, respectively. The sensing range of FOS head were 82 to 138 mm according to configuration cases. These results indicate that it is possible to measure load, tensile strain, and flexural strain using the proposed FOS head, and demonstrate that the sensitivities, the operating ranges, and the sensing range can be adjusted depending on the deformation characteristics of the measurement target.

Accuracy of X-ray computed tomography for dimensional metrology with employment of a new threshold selection method.

The article presents and discusses results of an experimental study regarding the accuracy of measurements performed with X-ray CT scanners. One of the main factors affecting the measurement result is definition of the threshold value between the air and the material. In this study, the results of measurements using two methods to determine the threshold value namely, the newly developed method and a well-known and commonly used method of ISO50%, were compared. A novel method is based on the measurement of an additional reference workpiece. The correction value, based on the measurement, is determined, and then it takes account when determining the threshold value between the air and the material. The study was performed using two types of gauges. These were workpieces of a specified volume of material (consisting of reference balls) and with the defined values of linear dimensions (in the form of cubes and cylinder). Using five different CT scanners, the conducted study yielded increase in the accuracy of measurements by applying the developed method in relation to the ISO50% automated method. In the case of volumetric test workpieces, relative measurement errors were reduced by 3 to 10 times for metrological CT scanners and from 50 to 30% for defectoscopy CT scanners. In the case of linear dimension measurements, average measurement errors were reduced twice.

Research on 3D measurement model by line structure light vision

For serious radial distortion and high precision measurement, 3D measurement model is studied in the paper. Based on the two-step calibration algorithm, a round initialization window is proposed to calculate the initial value of the camera parameters for nonlinear optimization. In order to solve the problem that the Supersonic Transport Evaluation Group algorithm of light stripe center extraction has a large amount of computation, a method is presented by normalized correlation coefficient (NCC) method and principal component analysis (PCA). Finally, the coordinates of the central stripe could be obtained based on the bilinear interpolation and parabolic fitting. With the parameters of the structured light plane that could be obtained by the coordinates of the central stripe, the height of block gauge is measured by the 3D measurement model. The experiment results showed that the average measurement error is 0.0191 mm, and the strip extraction speed is improved.

Electrochemical measurement of high concentrations of UCl3 and GdCl3 in molten LiCl-KCl eutectic

Electrochemical methods have been developed to measure metal ion concentrations in spent nuclear fuel electrorefiner by correlating concentration with current response. Analytes UCl3 and GdCl3 were studied in LiCl-KCl eutectic solvent at 773 K. A mixture matrix, which consisted of varying concentrations of UCl3 and GdCl3 from 1 to 10 wt% and from 1 to 3 wt%, respectively, was tested. Optimized normal pulse voltammetry (NPV) measurements were made on this mixture matrix and used for the concentration correlations. The accuracy of the prediction was improved by including solution resistance compensation and minimizing the working electrode surface area. The presence of GdCl3 showed no effect on the U3+ NPV reduction current, but high U concentrations affected the Gd3+ NPV reduction current. This is speculated to be due to increased migrational current in the molten salt mixture. The average relative measurement errors obtained were 1.6% and 2.7% for UCl3 and GdCl3 respectively.

Use of dual coolant displacing media for in-process optical measurement of form profiles

In-process measurement supports feedback control to reduce workpiece surface form error. Without it, the workpiece surface must be measured offline causing significant errors in workpiece positioning and reduced productivity. To offer better performance, a new in-process optical measurement method based on the use of dual coolant displacing media is proposed and studied, which uses an air and liquid phase together to resist coolant and to achieve in-process measurement. In the proposed new design, coolant is used to replace the previously used clean water to avoid coolant dilution. Compared with the previous methods, the distance between the applicator and the workpiece surface can be relaxed to 1 mm. The result is 4 times larger than before, thus permitting measurement of curved surfaces. The use of air is up to 1.5 times less than the best method previously available. For a sample workpiece with curved surfaces, the relative error of profile measurement under coolant conditions can be as small as 0.1% compared with the one under no coolant conditions. Problems in comparing measured 3D surfaces are discussed. A comparative study between a Bruker Npflex optical profiler and the developed new in-process optical profiler was conducted. For a surface area of 5.5 mm × 5.5 mm, the average measurement error under coolant conditions is only 0.693 µm. In addition, the error due to the new method is only 0.10 µm when compared between coolant and no coolant conditions. The effect of a thin liquid film on workpiece surface is discussed. The experimental results show that the new method can successfully solve the coolant dilution problem and is able to accurately measure the workpiece surface whilst fully submerged in the opaque coolant. The proposed new method is advantageous and should be very useful for in-process optical form profile measurement in precision machining.

Design and experiments of weeding teleoperated robot spectral sensor for winter rape and weed identification

The objective of this research was to eliminate the influence of environmental stray light on the measured spectral reflectance in a spectral sensor system used on a weeding teleoperated robot for rape fields. The system mainly consists of a light source, signal acquisition, and data processing. In this study, optical modulation technology and discrete Fourier transform method were used to carry out experiments based on four characteristic wavelengths. The results show that the experimental system can obtain a stable reflectivity value no matter whether the stray light changes slowly or dramatically in the field environment. Furthermore, the calibration equation of spectral reflectance was obtained by curve fitting based on a FieldSpec3 portable spectrometer. The determination coefficients are all close to 1, and the root-mean-square errors are small. Through verification experiments, the results show that the average measurement error is less than 5%. Hence, this proposed method would be very helpful in improving the accuracy and efficiency of the spectral reflectance measurement, which in turn provides a theoretical basis for weed identification during in-field weeding by teleoperated robots.

Design and Implementation of Pointer-Type Multi Meters Intelligent Recognition Device Based on ARM Platform

This paper adopts a low power consumption ARM Hisilicon mobile processing platform and OV4689 camera, combined with a new skeleton extraction based on distance transform algorithm and the improved Hough algorithm for multi meters real-time reading. The design and implementation of the device were completed. Experimental results shows that The average error of measurement was 0.005MPa, and the average reading time was 5s. The device had good stability and high accuracy which meets the needs of practical application.

Heterogeneous treatment effects with mismeasured endogenous treatment

This paper studies the identifying power of an instrumental variable in the nonparametric heterogeneous treatment effect framework when a binary treatment is mismeasured and endogenous. Using a binary instrumental variable, I characterize the sharp identified set for the local average treatment effect under the exclusion restriction of an instrument and the deterministic monotonicity of the true treatment in the instrument. Even allowing for general measurement error (e.g., the measurement error is endogenous), it is still possible to obtain finite bounds on the local average treatment effect. Notably, the Wald estimand is an upper bound on the local average treatment effect, but it is not the sharp bound in general. I also provide a confidence interval for the local average treatment effect with uniformly asymptotically valid size control. Furthermore, I demonstrate that the identification strategy of this paper offers a new use of repeated measurements for tightening the identified set. Local average treatment effect instrumental variable nonclassical measurement error endogenous measurement error partial identification C21 C26

Algoritma Interpolasi Nearest-Neighbor untuk Pendeteksian Sampul Pulsa Oscilometri Menggunakan Mikrokontroler Berbiaya Rendah

Non-invasive blood pressure measurement devices are widely available in the marketplace. Most of these devices use the oscillometric principle that store and analyze oscillometric waveforms during cuff deflation to obtain mean arterial pressure, systolic blood pressure and diastolic blood pressure. Those pressure values are determined from the oscillometric waveform envelope. Several methods to detect the envelope of oscillometric pulses utilize a complex algorithm that requires a large capacity memory and certainly difficult to process by a low memory capacity embedded system. A simple nearest-neighbor interpolation method is applied for oscillometric pulse envelope detection in non-invasive blood pressure measurement using microcontroller such ATmega328. The experiment yields 59 seconds average time to process the computation with 3.6% average percent error in blood pressure measurement.

Design of a Monitoring System for Level and Speed of Water Flow and River Condition Recorder Based on Android

Now a days, the condition of the river has been contaminated by householdwaste especially in the urban areas, the waste comes from people who are not responsible for the trash,so it potentially causes floods. Therefore, this research aims to design a system to monitor water level height and water speed as well as river condition recorder based on android. The use of ultrasonic sensor as an indicator to find out high levels of surface water, the optocoupler sensor as an indicator to know the speed of the water flow and IP cameras as a tool of monitoring the condition of the river are actual and direct. Research on the design of the ultrasonic sensor and optocoupler sensor resulted in average percentage error of measurement of 0.54% and 9.35%. IP camera that was designed as a visualization tool monitoring the condition of the river was able to produce on average the smallest delay 0ms. The notification system was implemented on the device users generating the biggest delay on average 22,9s and an average delay of the smallest 9,6s. QoS analysis on android gained the biggest delay of 1.64ms, the largest throughput of 81.01 Kb/s and packet loss of 0%. While QoS analysis on the website obtained the biggest delay of 58ms, the largest throughput of 19.3 KB/s and packet loss of 0%.