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Fibre optic sensors are used to measure various physical quantities, including polarisation plane rotation. Existing solutions for measuring the rotation of the plane of polarisation in optical fibres are based on sensors using tilted fibre Bragg gratings (TFBGs). Articles describing the possibilities of measuring the rotation of the plane of polarisation are generally concepts that show the effect of the rotation of the plane of polarisation on quantities such as the change in optical power of the light transmitted through the TFBG, or the change in the position of the selected minimum of the light spectrum. The only method that allows the measurement of the rotation of the plane of polarisation bases on optical spectrum analysis and requires manual calibration by an experienced operator. The paper proposes a fully automatic method of sensor calibration and processing the signal from a TFBG to measure the light polarisation plane rotation. The method uses the discrete wavelet transform (DWT) to process the light spectrum. An automatic algorithm to choose optimal DWT coefficients to use has been developed. The presented method offers calibration of light polarisation plane rotation angle sensors avoiding the influence of manufacturing imperfections of the measurement system components. In addition, it allows the calibration process to be fully automated without operator involvement. The developed measurement method is also fully automated. It allows measurement of angles of rotation in the range of 0-180, making it possible to distinguish between 0-90 and 90-180 rotation angle ranges without any problems. The mean square error of measurement over the entire range is 0.37 degrees, which is better than that of competing methods. In addition, an independent measurement method operating in the 82-98 rotation angle range is proposed to increase measurement precision in this range. [ABSTRACT FROM AUTHOR]

Accurately measuring gender and sex is crucial in public health and epidemiology. Iteratively reexamining how variables—including gender and sex—are conceptualized and operationalized is necessary to achieve impactful research. Reexamining gender and sex advances epidemiology toward its goals of health promotion and disease elimination. While we cannot reduce the complexities of sex and gender to simply an issue of measurement, striving to capture these concepts and experiences accurately must be an ongoing dialogue and practice—to the benefit of the field and population health. We assert that epidemiology must counteract misconceptions and accurately measure gender and sex in epidemiology. We aim to summarize existing critiques and guiding principles in measuring gender and sex that can be applied in practice. [ABSTRACT FROM AUTHOR]

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Przegląd Elektrotechniczny is the property of Przeglad Elektrotechniczny and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A rigid-flexible dual-arm space robot offers promising potential for on-orbit operation due to complementary strengths of its rigid and flexible manipulators. The rigid manipulator has the advantage of large payload capacity and high motion accuracy. The segmented linkage flexible manipulator is ideal for maneuvering in narrow, unstructured environments like internal satellite inspections and maintenance, due to its flexibility and slender body. However, there are inevitable tracking errors due to the multiple cable-driven mechanisms in the flexible manipulator. It's difficult to get the configuration and end pose of flexible manipulator without adding external sensors. To address these issues, this paper presents a method for configuration reconstruction and all-joint synchronous measurement of the flexible manipulator. The flexible manipulator is captured by the stereovision system mounted on the rigid manipulator. The links' equivalent center points are recognized by central moment method and edge line extraction method based on the natural characteristics. Joint - to - link kinematic model of flexible manipulator is established to measure joint angles and reconstruct configuration. Several simulations and experiments are carried out to validate the proposed method. The experimental results showed links' average measurement position errors were less than 13 mm and joint angles reconstructed using the proposed method had an error of approximately 0.35 °. These results demonstrate the accuracy and robustness of the proposed method. [ABSTRACT FROM AUTHOR]

This study aimed to analyze the intra-device agreement of a new linear position transducer (Vitruve, VT) and the inter-device agreement with a previously validated linear velocity transducer (T-Force System, TF) in different range of velocities. A group of 50 healthy, physically active men performed a progressive loading test during a bench press (BP) and full-squat (SQ) exercise with a simultaneous recording of two VT and one TF devices. The mean propulsive velocity (MPV) and peak of velocity (PV) were recorded for subsequent analysis. A set of statistics was used to determine the degree of agreement (Intraclass correlation coefficient [ICC], Lin's concordance correlation coefficient [CCC], mean square deviation [MSD], and variance of the difference between measurements [VMD]) and the error magnitude (standard error of measurement [SEM], smallest detectable change [SDC], and maximum errors [ME]) between devices. The established velocity ranges were as follows: >1.20 m·s−1; 1.20–0.95 m·s−1; 0.95–0.70 m·s−1; 0.70–0.45 m·s−1; ≤0.45 m·s−1 for BP; and >1.50 m·s−1; 1.50–1.25 m·s−1; 1.25–1.00 m·s−1; 1.00–0.75 m·s−1; and ≤0.75 m·s−1 for SQ. For the MPV, the VT system showed high intra- and inter-device agreement and moderate error magnitude with pooled data in both exercises. However, the level of agreement decreased (ICC: 0.790–0.996; CCC: 0.663–0.992) and the error increased (ME: 2.8–13.4% 1RM; SEM: 0.035–0.01 m·s−1) as the velocity range increased. For the PV, the magnitude of error was very high in both exercises. In conclusion, our results suggest that the VT system should only be used at MPVs below 0.45 m·s−1 for BP and 0.75 m·s−1 for SQ in order to obtain an accurate and reliable measurement, preferably using the MPV variable instead of the PV. Therefore, it appears that the VT system may not be appropriate for objectively monitoring resistance training and assessing strength performance along the entire spectrum of load-velocity curve. [ABSTRACT FROM AUTHOR]

There is a rather striking similarity between the capabilities of the measuring and process means, because both have as their object the study of variation. In reality, however, it must be understood that, since the process image is based on measurements, the variation of the measurements is included in that of the process expressed by capability calculations. The variation of measurements comes from different factors and it is the role of the quality engineer to discover them, quantify them, decide which ones are relevant, calculate the total variation and decide whether the equipment is capable or not, depending on the recommendations of the standard and their own experience. [ABSTRACT FROM AUTHOR]

In recent years, the accuracy of visual SLAM (Simultaneous Localization and Mapping) technology has seen significant improvements, making it a prominent area of research. However, within the current RGB-D SLAM systems, the estimation of 3D positions of feature points primarily relies on direct measurements from RGB-D depth cameras, which inherently contain measurement errors. Moreover, the potential of triangulation-based estimation for ORB (Oriented FAST and Rotated BRIEF) feature points remains underutilized. To address the singularity of measurement data, this paper proposes the integration of the ORB features, triangulation uncertainty estimation and depth measurements uncertainty estimation, for 3D positions of feature points. This integration is achieved using a CI (Covariance Intersection) filter, referred to as the CI-TEDM (Triangulation Estimates and Depth Measurements) method. Vision-based SLAM systems face significant challenges, particularly in environments, such as long straight corridors, weakly textured scenes, or during rapid motion, where tracking failures are common. To enhance the stability of visual SLAM, this paper introduces an improved CI-TEDM method by incorporating wheel encoder data. The mathematical model of the encoder is proposed, and detailed derivations of the encoder pre-integration model and error model are provided. Building on these improvements, we propose a novel tightly coupled visual-inertial RGB-D SLAM with encoder integration of ORB triangulation and depth measurement uncertainties. Validation on open-source datasets and real-world environments demonstrates that the proposed improvements significantly enhance the robustness of real-time state estimation and localization accuracy for intelligent vehicles in challenging environments. [ABSTRACT FROM AUTHOR]

Scholars employ two main measures of the executive constraints embedded in European Union laws: one is based on the variation in the use of different types of restrictions, and the second is based on the frequency of such use. They reflect two alternative conceptualizations of bureaucratic control. We label them, respectively, as the "toolbox perspective" and the "design perspective". We illustrate that the constraint frequency measure poses fewer validity problems in estimating legislators' intent to constrain implementation and tends to produce less severe measurement errors. We then evaluate the performance in estimating constraint variation of a recent computational application and identify potential drawbacks of automated learning from hand‐coded provisions. We lastly introduce a skeletal framework for a machine‐learning approach based on the syntactic structures employed by legislators that could improve the performance of this innovative technique. [ABSTRACT FROM AUTHOR]

Objectives: Test the effect of perceived likelihood of arrest on criminal behavior under a relaxed set of measurement assumptions. Specifically, responses that are commonly associated with inaccurate reporting practices–particularly, the 0%, 50%, and 100% categories–can be treated as partially identified. By doing so, scholars are able to bound the effect of perceived arrest risk on criminality, which provides more credible, although less precise, estimates of β 1 . Scholars can use this approach to not only produce more defensible findings, on the whole, but also gain insight into the possible threat posed by measurement misspecification. Methods: Point estimates of a perceived certainty effect were elicited via Quasi-Poisson regression using data derived from the Pathways to Desistance study. These estimates were subsequently bounded under progressively weaker measurement assumptions by a series of hill-climb algorithms. Results: In nine out of seventeen total algorithms, the worst-case bound remained in the expected direction and was statistically significant. For as long as a relatively minor level of response inaccuracy is assumed, supportive conclusions can be drawn. Conclusions: Support for a certainty effect can be found under relaxed measurement assumptions, up to a point. This not only provides further support for the deterrence hypothesis, but also implies the effect might be somewhat resilient to measurement error. [ABSTRACT FROM AUTHOR]

Indoor distance measurement technology utilizing Zigbee's Received Signal Strength Indication (RSSI) offers cost-effective and energy-efficient advantages, making it widely adopted for indoor distance measurement applications. However, challenges such as multipath effects, signal attenuation, and signal blockage often degrade the accuracy of distance measurements. Addressing these issues, this study proposes a combined filtering approach integrating Kalman filtering, Dixon's Q-test, Gaussian filtering, and mean filtering. Initially, the method evaluates Zigbee's transmission power, channel, and other parameters, analyzing their impact on RSSI values. Subsequently, it fits a signal propagation loss model based on actual measured data to understand the filtering algorithm's effect on distance measurement error. Experimental results demonstrate that the proposed method effectively improves the conversion relationship between RSSI and distance. The average distance measurement error, approximately 0.46 m, substantially outperforms errors derived from raw RSSI data. Consequently, this method offers enhanced distance measurement accuracy, making it particularly suitable for indoor positioning applications. [ABSTRACT FROM AUTHOR]

Deep hole measurement is a crucial step in both deep hole machining and deep hole maintenance. Single-camera vision presents promising prospects in deep hole measurement due to its simple structure and low-cost advantages. However, the measurement error caused by the heating of the imaging sensor makes it difficult to achieve the ideal measurement accuracy. To compensate for measurement errors induced by imaging sensor heating, this study proposes an error compensation method for laser and vision-based deep hole measurement instruments. This method predicts the pixel displacement of the entire field of view using the pixel displacement of fixed targets within the camera's field of view and compensates for measurement errors through a perspective transformation. Theoretical analysis indicates that the perspective projection matrix changes due to the heating of the imaging sensor, which causes the thermally induced measurement error of the camera. By analyzing the displacement of the fixed target point, it is possible to monitor changes in the perspective projection matrix and thus compensate for camera measurement errors. In compensation experiments, using target displacement effectively predicts pixel drift in the pixel coordinate system. After compensation, the pixel error was suppressed from 1.99 pixels to 0.393 pixels. Repetitive measurement tests of the deep hole measurement instrument validate the practicality and reliability of compensating for thermal-induced errors using perspective transformation. [ABSTRACT FROM AUTHOR]

There are currently few methods available to measure the conductance of water vapor through an orifice. The feasibility of the pressure rising method to measure the conductance of water vapor is analyzed by combining theory with experiment, indicating that the measurement error of this method increases with the decrease of intake volume, which is due to the strong adsorption characteristic of water vapor. To accurately obtain the relationship between the conductance of water vapor and the inlet pressure, a new method called the time-ratio method is proposed. This method calculates conductance by measuring the time of pressure change, reducing the effect of water vapor adsorption on the measurement effectively. Based on this method, a device is developed to provide a flow rate in the range of 3. 7×10-9 ~1. 5×10-5 Pa·m³· s-1. The measurement and theoretical values of conductance have good consistency, and the relative standard uncertainty of this time‑ratio method is 3. 3%. [ABSTRACT FROM AUTHOR]

Research on maltreatment exposure often demonstrates mixed findings and a potential explanation for this may be the measurement of maltreatment. One approach for addressing measurement concerns, which also accounts for maltreatment's multidimensional nature, is the use of a measurement or latent model. However, there is minimal evidence on the generalizability of this approach across populations of youth. This study examined measurement invariance of a one-factor maltreatment model across two samples of youth exposed to maltreatment using case file data from the SPARK and LONGSCAN datasets (N = 1286). Results showed that only partial metric invariance could be established for the one-factor model between SPARK and LONGSCAN subsamples, and neglect and emotional abuse indicators tended to show low factor loadings. Findings highlight the need to consider how potential differences in documentation and maltreatment rates influence model performance and the need for research on which maltreatment characteristics may best capture youths' experiences. [ABSTRACT FROM AUTHOR]

The final machining process, high-precision boring, can significantly affect the geometric error index of deep holes in gearboxes with thin-walled features. However, traditional mirror and mean compensation strategies are inadequate in compensating for the complex spatial and vector geometric errors, resulting in machining problems when boring deep holes in thin-walled boxes. This paper proposed a gradient compensation method that considered the geometric error and boring process characteristics to improve the current machining accuracy. The disadvantages of the classical compensation methods were analyzed in detail based on the error characteristics in boring deep holes. A gradient compensation was proposed and derived to improve the machining precision for boring deep holes on thin-walled boxes. On the other hand, a cutting test was designed and implemented using a control variable method in industrial cutting environment. Two different codes were programmed for boring process to validate the advantages of the proposed compensation method than the common. With the proposed compensation method, the geometric accuracy was improved by 86.12%, indicating that the proposed model was efficient for boring deep holes in thin-walled boxes. As a result, the proposed gradient compensation method successfully reduces the machining error of actual boring deep holes in thin-walled boxes. [ABSTRACT FROM AUTHOR]

The described system is designed to measure the field map of pulse bending magnets of accelerators. As an example, the magnet, which is an element of the particle bypass channel from the booster to the nuclotron of the NICA complex, which is being created at JINR, is chosen. Analyzing the capabilities of various methods in pulsed-field measurements and requirements for measurement errors in bending magnets better than 10–3 have led to the development of a method based on the use of Hall probes. The article substantiates the developed method, describes its capabilities, and the hardware developed for conducting measurements. In the conclusions, results of measurements of pulsed bending magnets of the booster–nuclotron channel are presented and analyzed. [ABSTRACT FROM AUTHOR]

How feelings change over time is a central topic in emotion research. To study these affective fluctuations, researchers often ask participants to repeatedly indicate how they feel on a self-report rating scale. Despite widespread recognition that this kind of data is subject to measurement error, the extent of this error remains an open question. Complementing many daily-life studies, this study aimed to investigate this question in an experimental setting. In such a setting, multiple trials follow each other at a fast pace, forcing experimenters to use a limited number of questions to measure affect during each trial. A total of 1398 participants completed a probabilistic reward task in which they were unknowingly presented with the same string of outcomes multiple times throughout the study. This allowed us to assess the test–retest consistency of their affective responses to the rating scales under investigation. We then compared these consistencies across different types of rating scales in hopes of finding out whether a given type of scale led to a greater consistency of affective measurements. Overall, we found moderate to good consistency of the affective measurements. Surprisingly, however, we found no differences in consistency across rating scales, which suggests that the specific rating scale that is used does not influence the measurement consistency. [ABSTRACT FROM AUTHOR]

A simple microwave photonic, reconfigurable, instantaneous frequency measurement system based on low-voltage thin-film lithium niobate on an insulator phase modulator is put forward and experimentally demonstrated. Changing the wavelength of the optical carrier can realize the flexibility of the frequency measurement range and accuracy, showing that during the ranges of 0–10 GHz, 3–15 GHz, and 12–18 GHz, the average measurement errors are 26.9 MHz, 44.57 MHz, and 13.6 MHz, respectively, thanks to the stacked integrated learning models. Moreover, this system is still able to respond to microwave signals of as low as −30 dBm with the frequency measurement error of 62.06 MHz, as that low half-wave voltage for the phase modulator effectively improves the sensitivity of the system. The general-purpose, miniaturized, reconfigurable, instantaneous frequency measurement modules have unlimited potential in areas such as radar detection and early warning reception. [ABSTRACT FROM AUTHOR]

Aiming at the shortcomings of the existing machine vision pose measurement technology, a pose measurement method based on monocular vision and a cooperative target is proposed. A planar target designed with circles and rings as the main body is dedicated to object pose measurement, and a feature point coordinate extraction and sorting algorithm is designed for this target to effectively extract image features on the target. The RANSAC algorithm and topology-based fitting for the intersection method are used to optimise data processing, further improving the accuracy of feature point coordinate extraction and ultimately achieving high-precision measurement of object poses. The experimental results show that the measurement accuracy of the roll angle perpendicular to the optical axis can reach 0.02°, and the repeatability can reach 0.0004° after removing the systematic error; the measurement accuracy of the pitch angle can reach 0.03°, and the repeatability can go to 0.002° after removing the systematic error. The measurement range of the pitch angle is [−30°, +30°]; the measurement range of the roll angle is [−179°, +179°]. The experimental results show that the system has high measurement accuracy and meets the requirements of high-precision measurement. [ABSTRACT FROM AUTHOR]

To guarantee the accuracy of sophisticated equipment in spacecraft, it is essential to evaluate the dynamic forces of vibration sources. In contrast to conventional rigid-based measuring approaches, a method for predicting the interference of dynamic forces from large sources on spacecraft considering vibration coupling is proposed. In addition, a flexible-based dynamic force measuring platform capable of withstanding large masses and mounting large-volume vibration sources is designed. After that, the experiments for calibrating the platform and acquiring unknown terms in the derived theoretical models are detailed. The principle prototype is then manufactured for feasibility verification. It is demonstrated that despite the low fundamental frequency of the measuring platform of 242.8 Hz, the measurement error of the flexible measuring platform is less than 8% when the coupling is taken into account, which is 29% lower than that without coupling. Additionally, the prediction error of disturbance forces is within 17%. As a result, the accuracy of the proposed dynamic force measurement and prediction of large vibration sources considering coupling is substantially improved, providing a good reference for aerospace applications. [ABSTRACT FROM AUTHOR]

Fill dam structures are generally considered safe, but frequent heavy rainfall in recent years due to climate change has increased their risk of collapse. Technologies for the monitoring and safety management of these structures have attracted considerable attention, and methods to utilize technologies such as artificial intelligence (AI) and Internet of Things (IoT) for maintenance have been investigated. However, the measurement and communication processes of sensors used in the IoT technology are prone to measurement errors. Moreover, the communication environment and frequency range used by unlicensed operators vary within a country. Technologies for accurate interpretation of measurement results and optimal communication are required to address these issues. In this study, a technology for dam safety management and communication environment optimization was developed using AIoT (AI+IoT), and its field applicability was verified. [ABSTRACT FROM AUTHOR]

Background: The Episodic Disability Questionnaire (EDQ) is a generic 35-item patient-reported outcome measure of presence, severity and episodic nature of disability. We assessed the measurement properties of the Episodic Disability Questionnaire (EDQ) with adults living with HIV. Methods: We conducted a measurement study with adults living with HIV in eight clinical settings in Canada, Ireland, United Kingdom, and United States. We electronically administered the EDQ followed by three reference measures (World Health Organization Disability Assessment Schedule; Patient Health Questionnaire; Social Support Scale) and a demographic questionnaire. We administered the EDQ only 1 week later. We assessed the internal consistency reliability (Cronbach's alpha; > 0.7 acceptable), and test–retest reliability (Intra Class Correlation Coefficient; > 0.7 acceptable). We estimated required change in EDQ domain scores to be 95% certain that a change was not due to measurement error (Minimum Detectable Change (MDC95%)). We evaluated construct validity by assessing 36 primary hypotheses of relationships between EDQ scores and scores on the reference measures (> 75% hypotheses confirmed indicated validity). Results: Three hundred fifty nine participants completed the questionnaires at time point 1, of which 321 (89%) completed the EDQ approximately 1 week later. Cronbach's alpha for internal consistency ranged from 0.84 (social domain) to 0.91 (day domain) for the EDQ severity scale, and 0.72 (uncertainty domain) to 0.88 (day domain) for the EDQ presence scale, and 0.87 (physical, cognitive, mental-emotional domains) to 0.89 (uncertainty domain) for the EDQ episodic scale. ICCs for test–retest reliability ranged from 0.79 (physical domain) to 0.88 (day domain) for the EDQ severity scale and from 0.71 (uncertainty domain) to 0.85 (day domain) for the EDQ presence scale. Highest precision was demonstrated in the severity scale for each domain (MDC95% range: 19–25 out of 100), followed by the presence (MDC95% range: 37–54) and episodic scales (MDC95% range:44–76). Twenty-nine of 36 (81%) construct validity hypotheses were confirmed. Conclusions: The EDQ possesses internal consistency reliability, construct validity, and test–retest reliability, with limited precision when administered electronically with adults living with HIV across in clinical settings in four countries. Given the measurement properties, the EDQ can be used for group level comparisons for research and program evaluation in adults living with HIV. [ABSTRACT FROM AUTHOR]

Freeform surfaces can realize optical systems with a wide field of view, high throughput, and high contrast. For constructing optical systems with freeform surfaces, measuring technology is essential. However, it is difficult to measure freeform surfaces by existing measurement methods. We have developed a new measurement method of the dragging three-point method (DTPM). To realize further improvement in the accuracy of the DTPM, we propose the DTPM with a circular path. Since the circular path is closed, the measurement error can be reduced by the boundary condition that the height and slope agree with at the start and end points of the measurement. To evaluate this method, we conducted the circular path measurement of an off-axis asphere. The measurement repeatability was RMS = 1.5 nm, and the result agreed well with that of an interferometric test; the difference was RMS = 17.2 nm. [ABSTRACT FROM AUTHOR]

Higher-order evidence is evidence about evidence. Epidemiologic examples of higher-order evidence include the settings where the study data constitute first-order evidence and estimates of misclassification comprise the second-order evidence (e.g., sensitivity, specificity) of a binary exposure or outcome collected in the main study. While sampling variability in higher-order evidence is typically acknowledged, higher-order evidence is often assumed to be free of measurement error (e.g., gold standard measures). Here we provide two examples, each with multiple scenarios where second-order evidence is imperfectly measured, and this measurement error can either amplify or attenuate standard corrections to first-order evidence. We propose a way to account for such imperfections that requires third-order evidence. Further illustrations and exploration of how higher-order evidence impacts results of epidemiologic studies is warranted. [ABSTRACT FROM AUTHOR]

We consider the role of a Turing machine in controlling measurement experiments and the corresponding revision of Measurement Theory, incorporating the notion of physical time in a theory we show to be realised by all types of measurements of extensive quantities found in the scientific literature. Surprisingly, when we try to mechanise certain aspects of the experimental procedures with Turing machines, we uncover that quantities have an inherent measurement complexity. We demonstrate that there is a relationship between the structure of a real number and the amount of time required to measure its digits, which leads to the emergence of complexity classes associated with measuring of the digits of a real number and a new form of uncertainty: When algorithms govern experiments in Physics, then, even in the limit of the application of the theory, even in the absence of measurement errors, precise measurements of quantities cannot always be made. [ABSTRACT FROM AUTHOR]

In this paper, the precise design of a high-power amplifier (HPA) is shown, along with the problems associated with the stability of "on-wafer" measurements. Here, techniques to predict possible oscillations are discussed to ensure the stability of a monolithic microwave-integrated circuit (MMIC). In addition, a deep reflection is made on the instabilities that occur when measuring both on wafer and using a mounted chip. Stability techniques are used as tools to characterize measurement results. Both a precise design and instabilities are shown through the design of a three-stage X-band HPA in gallium nitride (GaN) from the WIN Semiconductors Corp. foundry. As a result, satisfactory performance was obtained, achieving a maximum output power equal to 42 dBm and power-added efficiency of 32% at a 20 V drain bias. In addition to identifying critical points in the design or measurement of the HPA, this research shows that the stability of the amplifier can be verified through a simple analysis and that instabilities are often linked to errors in the measurement process or in the characterization of the measurement process. [ABSTRACT FROM AUTHOR]

This article proposes a measurement method using a multi-dimensional LED detection array, which can be used to obtain the flight parameters (i.e., impact coordinates, flight velocity, and incident angle) of a small flying object. Firstly, the composition of the proposed system and its detection principle are described in detail. Then, a calculation model is derived according to the geometrical relationship between the different LED detection arrays, which can calculate the above flight parameters. Furthermore, numerical simulations are performed to analyze the change trend in the measurement error of the proposed system, and it can be verified that its measurement performance meets the related requirements in theory. Finally, we use the proposed system and a high-speed camera system to carry out comparison experiments with two different reference velocities of 900 m/s and 700 m/s, and the results show that the maximum deviation in the measured absolute velocity is always less than 1 m/s and that the maximum deviations of the measured coordinates of x and y are not more than 2 mm within the effective measurement range. Therefore, the proposed measurement method is feasible and effective, and it can also meet the requirements of the measurement system. [ABSTRACT FROM AUTHOR]

We obtain the median-, the arithmetic mean–, and the weighted mean–based central estimates for the distance to M87 using all the measurements collated in literature. We then reconstruct the error distribution for the residuals of the combined measurements and also split them based on the tracers used. We then check for consistency with a Gaussian distribution and other symmetric distributions such as Cauchy, Laplacian, and Student's- t distributions. We find that when we analyze the combined data, the weighted mean–based estimates show a poor agreement with the Gaussian distribution, indicating that there are unaccounted systematic errors in some of the measurements. Therefore, the median-based estimate for the distance to M87 would be the most robust. This median-based distance modulus to M87 is given by 31.08 ± 0.09 mag and 31.07 ± 0.09 mag, with and without considering measurements categorized as "averages," respectively. [ABSTRACT FROM AUTHOR]

Copyright of Machine Tool & Hydraulics is the property of Guangzhou Mechanical Engineering Research Institute (GMERI) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Measuring the running accuracy of aerostatic bearings is challenging because of the high-precision requirements in rotational motion. This paper presents an ultra-high precision measurement method for aerostatic bearings using atomic force microscopy (AFM) as the displacement sensor. The Donaldson reversal method was used to separate the artifact form errors from the measurement results. A measurement system was developed with the integration of an AFM module. The effects of sensor nonlinearity, environmental noise, and structural vibration on the measurement results were effectively suppressed in the system. The experimental results show that the measurement achieves up to subnanometer accuracy. [ABSTRACT FROM AUTHOR]

Robot measurement systems with a binocular planar structured light camera (3D camera) installed on a robot end-effector are often used to measure workpieces' shapes and positions. However, the measurement accuracy is jointly influenced by the robot kinematics, camera-to-robot installation, and 3D camera measurement errors. Incomplete calibration of these errors can result in inaccurate measurements. This paper proposes a joint calibration method considering these three error types to achieve overall calibration. In this method, error models of the robot kinematics and camera-to-robot installation are formulated using Lie algebra. Then, a pillow error model is proposed for the 3D camera based on its error distribution and measurement principle. These error models are combined to construct a joint model based on homogeneous transformation. Finally, the calibration problem is transformed into a stepwise optimization problem that minimizes the sum of the relative position error between the calibrator and robot, and analytical solutions for the calibration parameters are derived. Simulation and experiment results demonstrate that the joint calibration method effectively improves the measurement accuracy, reducing the mean positioning error from over 2.5228 mm to 0.2629 mm and the mean distance error from over 0.1488 mm to 0.1232 mm. [ABSTRACT FROM AUTHOR]

The straightness error of guideways is one of the key indicators of an ultra-precision machine, which plays an important role in the machining accuracy of a workpiece. In order to measure the straightness error of a long-distance ultra-precision guideway accurately, a splicing measurement for the straightness error of a guideway using a high-precision flat mirror and displacement sensor was proposed in this paper, and the data splicing processing algorithm based on coordinate transformation was studied. Then, comparative experiments on a splicing measurement and direct measurement of the straightness error were carried out on a hydrostatic guideway grinder. The maximum difference between the two measurements was 0.3 μm, which was far less than the straightness error of 5.8 μm. The experiment demonstrated the correctness of the proposed splicing measurement method and data processing algorithm. To suppress the influence of the straightness error on machining accuracy, a straightness error compensation algorithm based on error rotation transformation and vertical axis position correction was proposed, and the grinding experiment of a plane optics with a size of 1400 mm × 500 mm was carried out. Without error compensation grinding, the flatness error of the element was 7.54 μm. After error compensation grinding, the flatness error was significantly reduced to 2.98 μm, which was less than the straightness errors of the guideways. These results demonstrated that the straightness error of the grinding machine had been well suppressed. [ABSTRACT FROM AUTHOR]

Over the last decade, Nitrogen Oxide (NOx) emissions have garnered significantly greater attention due to the worldwide emphasis on sustainable development strategies. In response to the issues of dynamic measurement delay and low measurement accuracy in the NOx sensors of heavy-duty diesel vehicles, a novel Multilayer Perceptron (MLP)–Random Forest Regression (RFR) fusion algorithm was proposed and explored in this research. The algorithm could help perform post-correction processing on the measurement results of diesel vehicle NOx sensors, thereby improving the reliability of the measurement results. The results show that the measurement errors of the On-board Nitrogen oxide Sensors (OBNS) were reduced significantly after the MLP-RFR fusion algorithm was corrected. Within the concentration range of 0–90 ppm, the absolute measurement error of the sensor was reduced to ±4 ppm, representing a decrease of 73.3%. Within the 91–1000 ppm concentration range, the relative measurement error was optimised from 35% to 17%, providing a reliable solution to improve the accuracy of the OBNS. The findings of this research make a substantial contribution towards enhancing the efficacy of the remote monitoring of emissions from heavy-duty diesel vehicles. [ABSTRACT FROM AUTHOR]

In the machining process for herringbone gears manufactured by numerical control gear-shaping machines, out-of-tolerance problems of symmetry error generally exist. This paper proposed a high-precision control of spatial symmetry error in the one-time forming machining for herringbone gear. To improve the machining symmetry accuracy and quality of herringbone gear, a mathematical model of measurement, evaluation and compensation for spatial symmetry error was established based on the least square method. Meanwhile, a new shaping machining method based on spatial symmetry error detection and compensation was proposed. The test results indicated that the proposed method can maintain symmetry within 0.02 mm. This study provided a novel spatial symmetry error detection and compensation machining method for herringbone gear that has advantages compared to traditional methods in terms of machining accuracy, efficiency, and continuous machining type. [ABSTRACT FROM AUTHOR]

In view of the problem that the measurement accuracy of screen gaps is affected by the R region of the transition rounded corner of the large-size flat back cover, a mobile vision system with dual linear motor synchronous drive is designed to realize precise positioning of monocular vision in 16 local image acquisition positions set in the R region. Full-size measurement of the R region is achieved using local information fusion to accurately measure the screen gap. First, to solve the problem of edge breaking and the blurring of local images, a region extraction and segmentation method based on block statistics is proposed to quickly obtain accurate outer edges. Then, an adaptive Hough line detection method based on dichotomy is proposed to accurately locate the outer edges. The experimental results show that the accuracy of region extraction and segmentation is up to 99.68% within 60 ms; the angle error and position error of line detection are less than 0.01° and 0.2 pixels, respectively. With optimal anti-interference performance, the proposed algorithm realizes the adaptive and accurate positioning of the outer edge within 200 ms; the measurement time and the measurement error of the measurement system are less than 6.0 s and 0.03 mm, respectively. [ABSTRACT FROM AUTHOR]

The Mann–Kendall test for trend has gained a lot of attention in a range of disciplines, especially in the environmental sciences. One of the drawbacks of the Mann–Kendall test when applied to real data is that no distinction can be made between meaningful and non-meaningful differences in subsequent observations. We introduce the concept of partial ties, which allows inferences while accounting for (non)meaningful difference. We introduce the modified statistic that accounts for such a concept and derive its variance estimator. We also present analytical results for the behaviour of the test in a class of contiguous alternatives. Simulation results which illustrate the added value of the test are presented. We apply our extended version of the test to some real data concerning blood donation in Europe. [ABSTRACT FROM AUTHOR]

The paper deals with the issue of calibration of an analogue force sensor with a voltage output. For measurement, the force sensor uses a deformation member with a tensometric bridge and a measuring amplifier. This measuring chain must be used for force measurement, but the measurement uncertainty of this measuring chain is not known. Force sensors are planned for use in intelligent traumatological external fixation systems. [ABSTRACT FROM AUTHOR]

Copyright of Technisches Messen is the property of De Gruyter and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Arc sag is an important parameter in the design and operation and maintenance of transmission lines and is directly related to the safety and reliability of grid operation. The current arc sag measurement method is inefficient and costly, which makes it difficult to meet the engineering demand for fast inspection of transmission lines. In view of this, this paper proposes an automatic spacer bar segmentation algorithm, CM-Mask-RCNN, that combines the CAB attention mechanism and MHSA self-attention mechanism, which automatically extracts the spacer bars and calculates the center coordinates, and combines classical algorithms such as beam method leveling, spatial front rendezvous, and spatial curve fitting, based on UAV inspection video data, to realize arc sag measurement with a low cost and high efficiency. It is experimentally verified that the CM-Mask-RCNN algorithm proposed in this paper achieves an AP index of 73.40% on the self-built dataset, which is better than the Yolact++, U-net, and Mask-RCNN algorithms. In addition, it is also verified that the adopted approach of fusing CAB and MHSA attention mechanisms can effectively improve the segmentation performance of the model, and this combination improves the model performance more significantly compared with other attention mechanisms, with an AP improvement of 2.24%. The algorithm in this paper was used to perform arc sag measurement experiments on 10 different transmission lines, and the measurement errors are all within ±2.5%, with an average error of −0.11, which verifies the effectiveness of the arc sag measurement method proposed in this paper for transmission lines. [ABSTRACT FROM AUTHOR]

Copyright of Trakya Journal of Education is the property of Trakya Journal of Education and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ways of reducing the error of measurement methods of frequency deviation and expanding the measurement ranges of frequency deviation are considered. The possibilities of reducing the error of the electronic counting frequency meter method using digital signal processing algorithms are investigated. Digital signal processing algorithms are implemented in software developed by the authors on a modern spectrum analyzer. The algorithm for digital signal processing with the spectrum analyzer is described. Using a mathematical model embedded in the calculation algorithm of the developed software, the measurement error of frequency deviation is estimated. The possibility of using the electronic counting frequency meter method with the help of digital signal processing algorithms of the spectrum analyzer has been experimentally investigated. We consider the error sources in the classical method of the electronic counting frequency meter and possible ways of their elimination. Comparisons of the proposed implementation of the electronic counting frequency meter method with the classical method, which is implemented in the State Primary Standard of the unit of frequency deviation GET 166-2020, are carried out. The proposed implementation of the method has expanded the measurement range of frequency deviation towards small values in comparison with the classical method of electronic counting frequency meter. Limitations and prospects of application of the investigated method in reference means of measuring frequency deviation based on analog-to-digital converters are considered. [ABSTRACT FROM AUTHOR]

High-precision electro-optic distance measurement (EDM) is essential for deformation monitoring. Although sub-ppm instrumental accuracy is already feasible with state-of-the-art commercial technology, the practically attainable accuracy on distances over more than a few hundred meters is limited by uncertainties in estimating the integral refractive index along the propagation path, which often results in measurement errors of several ppm. This paper presents a new instrumental basis for high-accuracy multispectral EDM using an optical supercontinuum to enable dispersion-based inline refractivity compensation. Initial experiments performed on two spectrally filtered bands of 590 and 890 nm from the supercontinuum show measurement precision better than 0.05 mm over 50 m for an acquisition time of around 3 ms on the individual bands. This represents a comparable performance to our previously reported results on 5 cm by over a range of 3 orders of magnitude longer, which can still be improved by increasing the acquisition time. The preliminary results indicate a relative accuracy of about 0.1 mm at 50 m on each wavelength. Improvement is possible by calibration and by implementing a self-reference scheme that mitigates slow drifts caused by power-to-phase coupling. The results reported herein thus indicate that the presented approach can be further developed for achieving sub-ppm accuracy of refractivity compensated distance measurements on practically useful ranges and under outdoor conditions. [ABSTRACT FROM AUTHOR]

Measurement error affects the quality of population orderings of an index and, hence, increases the misclassification of the poor and the non-poor groups and affects statistical inferences from binary regression models. Hence, the conclusions about the extent, profile, and distribution of poverty are likely to be misleading. However, the size and type (false positive/negatives) of classification error have remained untraceable in poverty research. This paper draws upon previous theoretical literature to develop a Bayesian-based estimator of population misclassification and binary-regression coefficient bias. The study uses the reliability values of existing poverty indices to set up a Monte Carlo study based on factor mixture models to illustrate the connections between measurement error, misclassification, and bias and evaluate the procedure and discusses its importance for real-world applications. [ABSTRACT FROM AUTHOR]

Crosshole Sonic Logging Tomography (CSLT) is an emerging innovative measurement system which provides information on the size, shape, and orientation of defects in a bored pile. In this paper, we quantify measurement precision of the CSTL system by a gage repeatability and reproducibility (R&R) study, in order to understand and model the effects of the test operators, defects, and the test machines on measurement error. We do this by setting up a test pile with three know defects and performing various measurement experiments. We use a feature extraction method to quantify measurement error. Overall, we find that the CSLT has satisfactory repeatability and reproducibility for practical usage of defect detection. [ABSTRACT FROM AUTHOR]

This work proposes a comparison among GaN and SiC device main parameters measured with a dedicated and low-cost embedded system, employing an STM32 microcontroller designed to the purpose. The system has the advantage to avoid the use of expensive laboratory measurement equipment to test the devices, allowing to obtain their behavior in operating conditions. The following KPIs (Key Performance Indicators) are measured and critically compared: threshold voltage, on-resistance and input capacitance. All the measurements are carried out in a short time interval and on a wide range of switching frequencies, ranging from 10 kHz to 1 MHz. This investigation is focused on the deviation of the figures of merit when the switching frequency changes, since it is crucial for wide-bandgap devices. The devised, low-cost, microcontroller unit allows high flexibility and system portability, while the employed equivalent-time sampling technique overcomes some issues related to the need of high sampling frequency. It allows good performances with common microcontroller embedded AD converters. To validate the proposed system, the obtained results have been compared with the time-domain waveforms acquired with a traditional laboratory oscilloscope and a study of the system's measurement errors has been carried out. Results show that GaN devices achieve a higher efficiency with respect to SiC devices in the considered range of switching frequencies. The on-resistance exhibited by GaN devices shows, as expected, an increase with frequency, which happens to switching losses, too. On the other hand, GaN devices are more sensitive to parasitic effects and the high dV/dt, due to the reduced switching times, can excite unwanted ringing phenomena. [ABSTRACT FROM AUTHOR]

In this paper, we argue that Williamson's arguments against luminosity and the KK principle do not work, at least in a scientific context. Both of these arguments are based on the presence of a so-called "buffer zone" between situations in which one is in a position to know p and situations in which one is in a position to know ¬p. In those positions belonging to the buffer zone ¬p holds, but one is not in a position to know ¬p. The presence of this buffer zone triggers two types of sorites arguments. We show that this kind of argument does not hold in a scientific context, where the buffer zone is controlled by a quantitative measurement of the experimental error. [ABSTRACT FROM AUTHOR]

The radial error is an important parameter to evaluate the performance of ultra-precision spindles. The three-point method has not yet been well applied in nanometer-scale measurement due to its disadvantages of harmonic suppression and the complicated error separation process. In order to verify that the three-point method can realize the nanometer-scale measurement of the radial error in the machining environment, an in situ measurement and evaluation system is established. Experiments are performed using the system, and a comparative experiment is conducted to verify the accuracy of the system. The average value and standard deviation of the measurement results are 23.096 nm and 0.556 nm, respectively. The in situ measurement result was in good agreement with the Donaldson reversal method using a commercially available spindle analyzer. [ABSTRACT FROM AUTHOR]

Background: To assess the impact of the lung cancer screening protocol recommended by the European Society of Thoracic Imaging (ESTI) on nodule diameter, volume, and density throughout different computed tomography (CT) scanners. Methods: An anthropomorphic chest phantom containing fourteen different-sized (range 3–12 mm) and CT-attenuated (100 HU, −630 HU and −800 HU, termed as solid, GG1 and GG2) pulmonary nodules was imaged on five CT scanners with institute-specific standard protocols (PS) and the lung cancer screening protocol recommended by ESTI (ESTI protocol, PE). Images were reconstructed with filtered back projection (FBP) and iterative reconstruction (REC). Image noise, nodule density and size (diameter/volume) were measured. Absolute percentage errors (APEs) of measurements were calculated. Results: Using PE, dosage variance between different scanners tended to decrease compared to PS, and the mean differences were statistically insignificant (p = 0.48). PS and PE(REC) showed significantly less image noise than PE(FBP) (p < 0.001). The smallest size measurement errors were noted with volumetric measurements in PE(REC) and highest with diametric measurements in PE(FBP). Volume performed better than diameter measurements in solid and GG1 nodules (p < 0.001). However, in GG2 nodules, this could not be observed (p = 0.20). Regarding nodule density, REC values were more consistent throughout different scanners and protocols. Conclusion: Considering radiation dose, image noise, nodule size, and density measurements, we fully endorse the ESTI screening protocol including the use of REC. For size measurements, volume should be preferred over diameter. [ABSTRACT FROM AUTHOR]