Method For Measurement Of Parameters Research Articles

Application of integrated binocular stereo vision measurement and wireless sensor system in athlete displacement test

Based on binocular stereo vision measurement and wireless sensing theory, this paper studies the measurement and analysis methods of athletes' movement displacement parameters. The main purpose is to explore the relationship between sports biomechanical parameters. The analysis reveals the laws of athletes 'movements, and provides theoretical guidance on athletes' attitude recognition and physical training. Based on the principle of binocular stereo vision, a non-contact displacement measurement system was developed. The displacement measurement system uses template matching to extract the image coordinates of the measurement points and restore the spatial coordinates of the measurement points through European 3D reconstruction, which improves the practicality of the measurement system. In the cantilever beam vibration test, the traditional displacement sensor and binocular image displacement measurement system are used to simultaneously measure the cantilever beam displacement. The experimental results show that the integrated displacement measurement system in this paper has higher accuracy and better stability.

A novel method of insulation parameters measurement based on hybrid flexible arc suppression device in distribution networks

As one kind of active arc suppression devices, the hybrid flexible arc suppression device (HFASD) with current-based arc suppression method can eliminate the ground-fault current during the single-line-to-ground (SLG) fault. One of the most important aspects for current-based arc suppression method is the insulation parameters measurement. The reference current of current-based arc suppression method is calculated by the insulation parameters, including the ground capacitance and ground leakage conductance. For the sake of obtaining high-precision reference current of current-based arc suppression method, the insulation parameters should be measured accurately. However, the most of existing methods of insulation parameters measurement should increase the additional device cost and measure inaccurately. In this paper, HFASD based on second-order generalized integrator phase-locked loop (SOGI-PLL) algorithm and twice injection current method is proposed to measure the insulation parameters under the normal condition of distribution networks. The simulation and experimental results verify the effectiveness of the proposed method under different influence factors.

Comprehensive review of floc growth and structure using electrocoagulation: Characterization, measurement, and influencing factors

• Floc growth and structure are crucial for removal efficiency; however, they have attracted little attention in the electrocoagulation process. • Reported floc structure parameters, and their measurement methods, are presented in detail. • Influencing factors, including current intensity, initial p H , EC cell design, power supply, stirring pattern, and temperature, are summarized. • The development of electrode materials and coupling techniques is promising for floc performance improvement. Electrocoagulation (EC) has received significant attention for wastewater treatment owing to its environmental sustainability. The high removal efficiency of EC depends on flocs with large, strong structures. Flocs that aggregate with coagulants, pollutant particles, and fine electrolytic bubbles (10–50 μm) are complex and fragile during EC. However, floc growth during EC has not been thoroughly studied, and their structures have not been described in detail compared to the flocs formed by chemical coagulation (CC). Herein, the current research on floc growth during EC is comprehensively reviewed. First, the characteristics of flocs grown using EC are introduced. Second, the floc size, strength, and fractal geometry are described in detail, revealing the floc structure. Third, these structural parameter measurement methods, such as equivalent diameter, three-dimensional (3D) reconstruction, scattering, strength factor, and velocity gradient, are presented. Next, since particle aggregation is affected by the chemical conditions and hydrodynamics within the reactor, several factors, such as initial pH, current intensity, stirring pattern, electrode design, power supply, and temperature, impacting floc growth are summarized. Finally, future research directions are proposed for exploring the floc structures grown during EC and optimizing electrode materials, such as air cathodes and porous metallic anodes. This review may help reveal the removal mechanisms for diverse pollutants using EC and provide a future standard for EC cell design.

Measurement of thermal deviation of flue-gas in crossover pass of single tangential boiler

Aiming at the problem of thermal deviation in crossover pass of single tangential boiler, an on-line measurement method of radiation parameters of high temperature coal particles based on radiation spectroscopy was proposed. A measurement system consisting of an optical fiber spectrometer system and a water-cooled structure probe was developed, which was used to measure the radiation parameters of high temperature coal particles in crossover pass of the boiler. The radiation spectra at 500–1000 nm band on the gas flow side of the final reheaters inlet section of a 660 MW ultra-supercritical boiler were measured by the system. According to Planck’s law, the distribution of coal particles temperature, emissivity and other parameters along the section was obtained by fitting parameter method. The results show that the burnout delay of pulverized coal particles caused by the air-stage combustion system and the radiant heat transfer deviation caused by the non-uniform concentration of coal particles are the main causes of the thermal deviation of the final reheaters. Under the condition of increasing yaw angle of SOFA nozzles, the ability of SOFA to alleviate the residual swirling flow is significant, and the temperature distribution of coal particles in the crossover pass is more uniform. However, due to the phenomenon of single-side particles accumulation still exists, the deviation of particles radiation intensity remains large, which cannot effectively reduce the steam temperature deviation in reheaters. Through differentially adjusting the angles of SOFA nozzles in vertical direction and horizontal direction, the phenomenon of single-side coal particles accumulation can be improved, the non-uniform radiation heat transfer of heat exchangers on both sides can be balanced, and the steam temperature deviation in final reheaters can be reduced.

A measurement method of motion parameters in aircraft ground tests using computer vision

The purpose of this work is aiming at the problem of high precision and large-scale measurement of motion parameters of aircraft ground test. Based on the traditional vision measurement method of motion parameters, a new measurement method of motion parameters based on intersected planes is discussed. Firstly, the measurement of 3D coordinates of laser spots was performed using the 3 D vision technique combined with plane constraints of curtain wall, the images of laser spot projected on the parallel curtain wall were processed using the centroid method, the calibration of multi-coordinates were unified by the unique coordinate system method, then the pose was solved using the proposed method that the normal vector of the intersect plane fixed on the vehicle is used. Finally, according to the measurement principle, the influence of spot center positioning, camera parameter calibration and target geometric error on the calculation results of aircraft motion parameters is analyzed, and the error propagation model is given. The experimental results show that in the measurement range of 8000 mm × 4000 mm × 4000 mm, the measurement error of attitude parameters is less than 0.14°, and the measurement error of position parameters is less than 2 mm. Compared with binocular stereo vision, the accuracy of attitude angle measurement is improved by 100%. Therefore, the measurement method proposed in this paper can achieve high precision and large-scale measurement of the motion parameters of the test aircraft.

Warhead Fragments’ Distribution Measurement Method by a Multiscreen Sensors’ Intersection Test Mechanism and Equivalent Target Damage Probability Calculation

To scientifically evaluate the damage effectiveness of a projectile explosion on the equivalent target, this article studies a warhead fragment distribution parameters’ measurement method based on a six-screen-sensors’ intersection test system; establishes a parameter calculation model of the warhead fragment hitting the equivalent target, the time and space constraints’ discriminant model of six infrared detection screens, and the time-value-matching model of multiple warhead fragments; and gives the calculation of the specific fragment distribution position and the time-matching algorithm of each infrared detection screen. According to the obtained warhead fragment parameters, a calculation method of the damage probability of equivalent target is constructed. Through experiments and analysis, it is verified that the established warhead fragment parameter measurement method and the damage probability model of the equivalent target are scientific.

Дослідження впливу параметрів проводу на режими роботи повітряних ліній 110 кВ

The article considers possibility using eddy current methods, non-destructive testing, in the power industry for contactless measurement instant parameters wires overhead power lines. There have been analyzed, with applied amplitude and phase methods of non-destructive testing, the change instant parameters of steel- aluminum wires with cross-section 240/32 mm2, which are mostly used for overhead power lines 110 kV. Made experimental research have revealed, that with increasing mechanical stresses on the wire and increasing its temperature decreases the electrical conductivity of the wire and increases its resistivity and, accordingly, increases the active resistance of the wire. The results of the presented experimental measurements show that the applied mechanical force on the wire leads to its elongation, in result it increased sagging and possible breakage of the wire, what complicates the operation mode of the line, and with increasing active resistance of the wire at constant current load, decreases transmitted power, and its losses increase, which affects the capacity of power line. To confirm this, using the experimental data, analyzed the capacity of power line and loss of active power of the 110 kV overhead line. The calculation of the relative error confirms the reliability of the results. The researches, which is based on experimental determinations of the influence of mechanical stresses and temperature on the parameters of the steel-aluminum wire with cross-section 240/32 mm2, substantiates the feasibility of using eddy current methods (non- destructive testing), namely the joint use of amplitude and phase methods for contactless measurement of instant parameters overhead power lines wires, for improving operation modes management of electrical networks in real time.

Fast Dynamic Frequency Response-Based Multiparameter Measurement in Spin-Exchange Relaxation-Free Comagnetometers

As the measurement of multiple parameters in a spin-exchange relaxation-free (SERF) comagnetometer requires a long time and complex experimentation, we present a novel dynamic frequency response-based method for the accurate and rapid measurement of key parameters in a SERF comagnetometer. By testing the dynamic frequency response to a transverse oscillating magnetic field, we can obtain multiple parameters simultaneously and quickly without interrupting the operation of the comagnetometer. This method simultaneously measures the nuclear longitudinal relaxation rate and alkali metal number density within minutes, with uncertainties of less than 20.8% and 14.0%, respectively. The main error sources in the nuclear longitudinal relaxation rate and alkali metal number density are the spin-exchange rate constant and spin-exchange enhancement factor, respectively. In addition, the polarization of alkali metal and noble gas atoms can be obtained during the experimental process, and the fast measurement of these parameters is beneficial for applications requiring simultaneous and in situ measurement of spin ensemble performance.

A Calibration Scheme With Combination of the Optical Shaft Encoder and Laser Triangulation Sensor for Low-Frequency Angular Acceleration Rotary Table

A low-frequency angular acceleration rotary table (LFAART) is capable of sinusoidal motion around a fixed position and essential to verify dynamic characteristics of a gyroscope device. The table’s performance at different swinging frequencies and amplitudes needs to be calibrated to realize traceability. However, there has been little research on the LFAART calibration. Besides, the existing measurement methods of sinusoidal angular motion parameters are not adequate for the needs of the LFAART calibration in terms of measurement range, precision, and feasibility. This article presents a calibration scheme combining an optical shaft encoder and a laser triangulation sensor. When the rotation amplitude covers sufficient slots of the scale grating, the optical shaft encoder is applied, while the laser triangulation sensor is used for a tiny amplitude motion. An algorithm is proposed to accurately calculate the angular acceleration amplitude and frequency of the rotation utilizing sinusoidal phase-modulated signals of the optical shaft encoder output. Singular zero-crossings of the series are discarded, and intervals of reversing moments are recognized according to the signal derivative’s sign at remaining zero-crossings. Then intervals are divided into subintervals to obtain accurate reversing moments. Finally, angular displacements between two adjacent reversing moments are estimated based on the fringe counting method, and the amplitude and frequency are calculated. The measurement uncertainty analysis and experiment demonstrate that the calibration scheme, including the algorithm, possesses high accuracy and resolution, wide range, and good operability, which perfectly solves the rotation’s angular acceleration amplitude and frequency.

Terahertz measurement method of liquid electromagnetic parameters based on Gaussian mixture model

针对使用透射式测量系统难以提取太赫兹波段高吸收样品电磁参数的难题，采用反射式时域光谱系统分别测量了极性液体和非极性液体的时域光谱。通过时域有限积分算法对太赫兹波在样品中的传播特性进行建模，并使用高斯混合模型重新构建反射光谱，从噪声中恢复了原始的太赫兹时域信号，解决了反射式系统信号易受干扰导致的电磁参数发生伪波动的问题。实验结果表明，使用恢复信号计算得到的水和液体石蜡在0.4 THz～2 THz波段的折射率和消光系数，与使用原始信号计算得到的结果相比，有效地消除了波动现象，去趋势波动分析（detrended fluctuation analysis, DFA）标度指数较之原始信号计算值分别上升了7%、3%、29%、31%，验证了该方法的有效性和正确性。

Application and analysis of carbon dioxide refrigeration system with ejector in commercial super cold cabinet

In this paper, the transcritical CO2 refrigeration system with ejector is applied to a commercial ultra-cold cabinet. The influence of the key operating parameters of the ejector on the system performance is analyzed, and the measurement method of the experimental parameters is proposed. The results show that the ejector can eject the low pressure refrigerant into the reservoir by using the energy of the large pressure difference throttle, and the COP of the system can be increased by 9%-19%. This paper provides a theoretical basis for the design, development and optimization of CO2 refrigeration and air conditioning system with ejector.

Current Status and Development Trend of Heat Transfer Mechanism Research of Fruit Heat Treatment

Heat treatment technology is widely considered to be an auxiliary sterilization and post-processing technology which can improve fruit quality, this paper introduced fruits and vegetables heat treatment methods domestic and overseas, including heat transfer model commonly used in heat treatment, measurement method of fruit and vegetable physical parameters which can influent heat treatment process, proposed suggestion for improving heat treatment effect from the point of view of heat transfer, at last analyzed defects of current heat treatment technology comprehensively, as well as the difference of heat treatment domestic and overseas and the development trend in the future.

REPRODUCIBILITY OF S2-ALAR ILIAC SCREW MORPHOMETRIC ANALYSIS.

ABSTRACTObjective: To evaluate the reproducibility of a S2-alar iliac (S2AI) screw parameters measurement method by inter and intraobserver reliability.Methods: Cross-sectional study, considering computed tomography exams. Morphometric analysis was performed by multiplanar reconstructions. Screw length, diameter and trajectory angles were the studied variables. To analyze the measurements reproducibility, intraclass correlation coefficient (ICC) was used.Results: Interobserver reliability was classified as strong for screw shortest length (ICC: 0.742) and diameter (ICC: 0.699). Interobserver reliability was classified as moderate for screw longest length (ICC: 0.553) and for screw trajectory angles in the axial plane for the longest (ICC: 0.478) and for the shortest lengths (ICC: 0.591). Intraobserver reliability was interpreted as excellent for screw shortest (ICC: 0.932) and longest lengths (ICC: 0.962) and diameter (ICC: 0.770) and screw trajectory angles in the axial plane for the screw longest (ICC: 0.773) and shortest lengths (ICC: 0.862). There were weak interobserver and strong intraobserver reliabilities for trajectory angle in sagittal plane, but no statistical significance was found.Conclusion: Inter and intraobserver reliability of S2AI screw morphometric parameters were interpreted from moderate to excellent in almost all studied variables, except for the screw trajectory angle in the sagittal plane measurement. Level of Evidence IV, Diagnostic Studies - Investigating a Diagnostic Test.

Application of Motion Sensor Fusion in Special Competitive Sports

With the advancement of science and technology and the rapid development of the field of intelligence, new sensor technology has also made great progress. The availability and use speed of motion sensor technology are increasing rapidly, while its cost is reduced, the overall performance is also more complete, and the application fields are becoming more and more extensive. Based on the introduction and summary of the human body structure and the characteristics of sports, in order to facilitate the study of human movement, this article establishes a rod‐shaped sports model and a human body coordinate system that is convenient for analysis and calculation. Through the analysis of commonly used sports parameter measurement methods, a method of using acceleration parameters for sports measurement and analysis is proposed. The motion sensor is used to measure the movement of the limbs, and the mathematical relationship between acceleration parameters and speed, displacement, and other parameters is used to solve other motion parameters, so as to analyze the posture and movement trajectory of sports. We developed a motion acquisition system which is divided into two parts: a signal acquisition unit and a data processing unit. With ARM7 and three‐axis accelerometer ADXL330 as the core, it can realize information acquisition and data analysis of up to 5 sensor network nodes. The topology management platform mainly formulates the sleep strategy of suitable nodes according to the changes of the sensor network topology, maintains the connectivity of the network, and ensures the effective transmission of data. On the basis of the performance test of the system, a sports measurement experiment was carried out, and it was applied to the control of competitive sports for reliability testing. The experimental results verified the use of the sports information acquisition system to collect and analyze sports information.

Intelligent parameters measurement of electrical structure of medium frequency DC resistance spot welding system

Three phase medium frequency direct current (DC) resistance spot welding (RSW) machine has a complex electrical structure. Because the structure included various electrical components, it is hard to establish an accurate and integrated numerical model to simulate the energy delivery and control process. This study employed a particle swarm optimization (PSO) algorithm to conduct an intelligent parameters measurement. The measurement process included three procedures, based on electrical and physical characteristics of the objective electrical system. To verify the accuracy and reliability of the measurement, another numerical model established by MATLAB Simulink was employed. The comparative results showed that the maximum error of all measured parameters was 1%, which meant that the proposed intelligent parameter measurement method was effective, and convinced measurement results can be obtained. This study can benefit to establish a full process numerical calculation or evaluation model of the medium frequency DC RSW system.

Contemporary principles for solving the problem in noise reduction from railway rolling stock

The statistical and monitoring data confirm the significant impact of the operational mode on the most important noise and vibration parameters, which is relevant for ensuring the efficiency and quality of the operational process with regard to ergonomic and environmental requirements. The article analyzes the acoustic parameters of rolling stock of the railway, emphasizes the peculiarities of noise emission from various elements of rolling stock and a track. Existing approaches towards solving the problem in the organization of railway noise control are outlined. On the basis of existing modern methods for measurement and analysis of acoustic parameters, the authors propose conceptual approaches toward monitoring the acoustic parameters, predicting noise characteristics and constructing the noise maps of railways. The algorithm of the developed acoustic model for the operational monitoring of noise load and the possibility to compile a case of noise maps for Ukrzaliznytsia is presented. The proposed algorithm allows at given basic design parameters and speed of rolling stock, known sound-absorbing and dissipative characteristics of all elements to carry out a rational selection of noise-protective measures in accordance with the sanitary noise regulations for a specific receptive facility.

Mechanical methods for state determination of Lithium-Ion secondary batteries: A review

Lithium-Ion batteries are the key technology to power mobile devices, all types of electric vehicles, and for use in stationary energy storage. Much attention has been paid in research to improve the performance of active materials for Lithium-Ion batteries, however, for optimal, long and safe operation, detailed knowledge of -among others- the state-of-charge and the state-of-health of the battery is paramount both in laboratory use, as well as during application by the battery management system. Today’s systems often derive their estimators from data of the voltage, current and temperature measurements, which can lead to inaccurate estimations of values during operation. Mechanical based measurements became very popular recently to fill the gap in data by complementing conventional measurements and thus provide more accurate information about the internal state of Lithium-Ion batteries. This review aims to present the current state of this promising topic for both laboratory use and applications on non-destructive in-situ and in-operando methods for measurement of mechanical battery parameters like expansion, strain and force, experimental modal analysis, ultrasonic probing and acoustic emission technologies. The intention of this summary is to provide insights in this emerging topic by showing benefits, drawbacks, possibilities and applications of each technique and compare those to each other, thus providing the readers with a deep insight into the topic.

Calibration on the Fly—A Novel Two-Port S-Parameter Measurement Method for On-Wafer Leaky Systems

In this article, we present a two-port on-wafer scattering parameter measurement method to tackle the issue of crosstalk between probes. The proposed method treats the crosstalk separately during the system calibration and the device measurement stages because the crosstalk during these stages is often different due to changes in the measurement conditions after the probes have been calibrated. For example, device under test (DUT) and calibration standards are often situated on different substrates, or the distance between probes during calibration is different from that during DUT measurement. Based on this concept, we develop a new error model in which the crosstalk is treated as a standalone two-port error network in parallel with the two-port calibration standards or DUTs. The two-port crosstalk error generated during probing, ECT, is removed in the system calibration and corrected during the measurement of the DUT by using a dummy pair of opencircuit standards that are fabricated on the same substrate as the DUT. Since the crosstalk is corrected while measuring the DUT, rather than during system calibration, we call this method “calibration on the fly” (COF). The method is demonstrated using measurements of a 10-dB attenuator between 140 and 220 GHz.

A two-stage vision-based method for measuring the key parameters of ball screws

Ball screws are crucial for improving the reliability and interchangeability of transmission mechanical systems; however, existing contact measurement methods that utilise stylus contact are not efficient, which precludes their use for rapid in-situ geometry evaluation. This paper presents a vision-based two-stage method for rapid measurement of key parameters (raceway arc radii and centre distance) of ball screws. The edge contour information is extracted from the acquired image using the dual-tree complex wavelet transform and non-maximal suppression. In the matching stage, a shape-matching algorithm is used for detecting approximate geometrical centres of raceway arcs. The refinement stage, on the other hand, is implemented for acquiring precise dimensional results. Furthermore, the method of averaging multiple measurements is performed to suppress random noise. A comparative experiment is presented to validate the robustness of the proposed method. Based on experimental results, the calculated mean absolute errors in the measurement of the two raceway arc radii and the centre distance are found to be 0.0082 mm, 0.0079 mm and 0.0055 mm, respectively. This study therefore paves the way for key parameter measurement without removing ball screws.

Anthropometric Parameter Measurement from Equivariant Multi-view Images

In this paper, we propose an anthropometric parameter measurement method that any customized parameter can be measured online by the pre-selected endpoints on the reconstructed 3D body models of equivariant multi-view images. The method includes 3D body model reconstruction, anthropometric parameter measurement, and parameter modification. In 3D body model reconstruction, we detect and segment the human body from its background and reconstruct a generative 3D body model from the segmented image with deep learning. And then we measure anthropometric parameter on the reconstructed 3D body model of each view. Before parameter measurement, we manually pre-select endpoints associated with all anthropometric parameters on the reconstructed 3D body model since all vertices of the reconstructed body model are ordered. However, the information of a single-view image is insufficient and the measurement result is varied regularly by the view changes. To improve the measurement accuracy, we design a convolutional neural network in the last step which can regress more accurate anthropometric parameters from equivariant multi-view measurements. Experimental results on the representative dataset demonstrate that the proposed method can measure planar and spatial anthropometric parameters automatically with comparable performance.