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Steering wheel angle is an important and essential parameter of the navigation control of autonomous wheeled vehicles. At present, the combination of rotary angle sensors and four-link mechanisms is the main sensing approach for steering wheel angle with high measurement accuracy, which is widely adopted in autonomous agriculture vehicles. However, in a complex and challenging farmland environment, there are a series of prominent problems such as complicated installation and debugging, spattered mud blocking the parallel four-bar mechanism, breakage of the sensor wire during operation, and separate calibrations for different vehicles. To avoid the above problems, a novel dynamic measurement method for steering wheel angle is presented based on vehicle attitude information and a non-contact attitude sensor. First, the working principle of the proposed measurement method and the effect of zero position error on measurement accuracy and path tracking are analyzed. Then, an optimization algorithm for zero position error of steering wheel angle is proposed. The experimental platform is assembled based on a 2ZG-6DM rice transplanter by software design and hardware modification. Finally, comparative tests are conducted to demonstrate the effectiveness and priority of the proposed dynamic sensing method. Experimental results show that the average absolute error of the straight path is 0.057° and the corresponding standard deviation of the error is 0.483°. The average absolute error of the turning path is 0.686° and the standard deviation of the error is 0.931°. This implies the proposed dynamic sensing method can accurately realize the collection of the steering wheel angle. Compared to the traditional measurement method, the proposed dynamic sensing method greatly improves the measurement reliability of the steering wheel angle and avoids complicated installation and debugging of different vehicles. The separate calibrations for different vehicles are not needed since the proposed measurement method is not dependent on the kinematic models of the vehicles. Given that the attitude sensor can be installed at a higher position on the wheel, sensor damage from mud blocking and the sensor wire breaking is also avoided. [ABSTRACT FROM AUTHOR]

Objective: Diabetic foot ulcer (DFU) is a severe complication with high mortality. High plantar pressure and poor microcirculation are considered main causes of DFU. The specific aims were to provide a novel technique for real‐time measurement of plantar skin blood flow (SBF) under walking‐like pressure stimulus and delineate the first plantar metatarsal head dynamic microcirculation characteristics because of life‐like loading conditions in healthy individuals. Methods: Twenty young healthy participants (14 male and 6 female) were recruited. The baseline (i.e., unloaded) SBF of soft tissue under the first metatarsal head were measured using laser Doppler flowmetry (LDF). A custom‐made machine was utilized to replicate daily walking pressure exertion for 5 min. The exerted plantar force was adjusted from 10 N (127.3 kPa) to 40 N (509.3 kPa) at an increase of 5 N (63.7 kPa). Real‐time SBF was acquired using the LDF. After each pressure exertion, postload SBF was measured for comparative purposes. Statistical analysis was performed using the R software. Results: All levels of immediate‐load and postload SBF increased significantly compared with baseline values. As the exerted load increased, the postload and immediate‐load SBF tended to increase until the exerted load reached 35 N (445.6 kPa). However, in immediate‐load data, the increasing trend tended to level off as the exerted pressure increased from 15 N (191.0 kPa) to 25 N (318.3 kPa). For postload and immediate‐load SBF, they both peaked at 35 N (445.6 kPa). However, when the exerted force exceeds 35 N (445.6 kPa), both the immediate‐load and postload SBF values started to decrease. Conclusions: Our study offered a novel real‐time plantar soft tissue microcirculation measurement technique under dynamic conditions. For the first metatarsal head of healthy people, 20 N (254.6 kPa)‐plantar pressure has a fair microcirculation stimulus compared with higher pressure. There might be a pressure threshold at 35 N (445.6 kPa) for the first metatarsal head, and soft tissue microcirculation may decrease when local pressure exceeds it. [ABSTRACT FROM AUTHOR]

Phase-shifting profilometry (PSP) is one of the most widely available methods in three-dimensional (3D) measurement. However, PSP is not suitable for dynamic measurements due to multiple projections. The color fringe projection profilometry(CFPP) can encode three grayscale fringe patterns in a single color pattern, preserving the robustness of PSP while enabling dynamic measurements. But for the CFPP measurement system, color coupling and imbalance phenomena are inevitable between the RGB channels, which increases the measurement error. This paper proposes a background intensity calibration (BIC) method to correct the color imbalance and reconstruct 3D shapes by a single-shot projected-captured. First, capture a color fringe image and extract the background intensity by searching the upper and lower envelopes to get three background-free fringe images; Secondly, solve the normalized coefficient to balance the three background-free images. As a result, a color fringe image can be split into three phase-shifting fringe images with the normalized modulation intensity and good sinusoidal aiming to perform phase demodulation by three-step PSP; Thirdly, the demodulation phase is unwrapped using a simple solving fringe orders algorithm based on a positive and negative binarization (PNB) method. Several experiments on dynamic scenes were performed, verifying that the measurement speed and accuracy of the proposed BIC method are not limited by the object moving, which can achieve fast, dense, and accurate 3D measurements. [ABSTRACT FROM AUTHOR]

Hot forming is an effective approach for improving the formability of ultrathin metal sheets, such as those made of stainless steel and pure titanium. However, the increased friction coefficient between the tool and the high-temperature metal sheet negatively affects material flow during hot forming, potentially resulting in severe local thinning or even cracking. This study explores the frictional behavior of 0.1 mm thick ferritic stainless steel (FSS) and commercially pure titanium (CP-Ti) sheets at elevated temperatures. A friction testing apparatus was developed to measure the friction coefficients of these metal sheets from room temperature (25 °C) up to 600 °C. The friction coefficient of the FSS sheet increased monotonically with temperature, whereas that of the CP-Ti sheet first increased and then decreased. Post-friction testing microscopic examination demonstrated that built-up edges formed on the surfaces of the friction blocks when rubbed against the stainless steel, contributing to the higher friction coefficients. This study provides a foundation for understanding frictional behavior during the hot forming of ultrathin metal sheets. [ABSTRACT FROM AUTHOR]

Masonry arch bridges are an integral part of the European transportation infrastructure. Regular inspections are critical to ensure the safe operation of these bridges and also to preserve historical heritage. Despite recent advancements in assessment techniques, monitoring masonry arch bridges remains a difficult and important research topic. This paper describes a proof-of-concept study carried out on a masonry arch rail bridge in Gavirate, Italy, to investigate the dynamic responses of the bridge to train-induced moving loads. The dynamic measurements are obtained by a distributed fiber optic sensing system that enables a novel inspection of the integrity of masonry arch bridges. The focus of this field study is to quantify the dynamic strain induced by train moving loads and reveal the masonry arch bridge's dynamic behaviors through the use of an innovative distributed fiber optical sensing-based technique. The results may provide a useful guideline for the application of distributed fiber optical sensing to monitoring masonry arch bridges. [ABSTRACT FROM AUTHOR]

Picking cherry tomatoes is a time-consuming and labour-intensive task, and robots are an alternative solution to address this issue. The end effector is a key component of the harvesting robot, and it is crucial for achieving automated harvesting of cherry tomatoes. To develop efficient end effectors for picking robots, this study proposes a method to aid end effector design by evaluating and analysing picking patterns of cherry tomatoes. Based on manual picking methods, four potential robot picking patterns are proposed: pressing–breaking combination, pulling, pulling–rotating combination and twisting. A dynamic measurement system based on multi-sensor fusion was developed to measure applied forces and angles during the picking process. Based on the selected picking patterns, two pneumatically controlled picking end effectors, namely, a vacuum end effector and a rotating end effector, were designed. The results of the dynamic measurement experiment and the picking pattern evaluation indicated that the recommended order of picking patterns was twisting, pulling, pulling–rotating combination and pressing–breaking combination in descending order. The picking performance test results of the end effector revealed that for the vacuum end effector, the picking success rate was 66.3 %, whereas the detachment failure was the main reason for picking failure. For the rotating end effector, the picking success rate was 70.1 %, whereas localisation failure and collision were the main reasons for picking failure. This study provides a valuable reference and theoretical analysis basis for the development of cherry tomato picking robots and the design of the end effector in the future. • A method for analysing picking patterns to aid end-effector design is proposed. • Four feasible picking patterns for robot harvesting of cherry tomatoes are proposed. • A dynamic measurement system is developed to measure force, angle and dynamic change. • A vacuum end-effector and a rotating end-effector are developed. • The pulling and twisting are the preferred picking patterns for cherry tomato robots. [ABSTRACT FROM AUTHOR]

Steering wheel angle is an important and essential parameter of the navigation control of autonomous wheeled vehicles. At present, the combination of rotary angle sensors and four-link mechanisms is the main sensing approach for steering wheel angle with high measurement accuracy, which is widely adopted in autonomous agriculture vehicles. However, in a complex and challenging farmland environment, there are a series of prominent problems such as complicated installation and debugging, spattered mud blocking the parallel four-bar mechanism, breakage of the sensor wire during operation, and separate calibrations for different vehicles. To avoid the above problems, a novel dynamic measurement method for steering wheel angle is presented based on vehicle attitude information and a non-contact attitude sensor. First, the working principle of the proposed measurement method and the effect of zero position error on measurement accuracy and path tracking are analyzed. Then, an optimization algorithm for zero position error of steering wheel angle is proposed. The experimental platform is assembled based on a 2ZG-6DM rice transplanter by software design and hardware modification. Finally, comparative tests are conducted to demonstrate the effectiveness and priority of the proposed dynamic sensing method. Experimental results show that the average absolute error of the straight path is 0.057° and the corresponding standard deviation of the error is 0.483°. The average absolute error of the turning path is 0.686° and the standard deviation of the error is 0.931°. This implies the proposed dynamic sensing method can accurately realize the collection of the steering wheel angle. Compared to the traditional measurement method, the proposed dynamic sensing method greatly improves the measurement reliability of the steering wheel angle and avoids complicated installation and debugging of different vehicles. The separate calibrations for different vehicles are not needed since the proposed measurement method is not dependent on the kinematic models of the vehicles. Given that the attitude sensor can be installed at a higher position on the wheel, sensor damage from mud blocking and the sensor wire breaking is also avoided.

This paper presents a review of publications on methods for estimating the dynamic measurement error and methods for its correction. The error components are due to the dynamic properties (inertia) of the sensor and the additive noise at its output. A method is proposed for estimating and reducing the dynamic measurement error based on the principle of adaptive linear prediction or adaptive linear signal amplification. This approach generates an error estimation signal based on the result of comparing a delayed copy of the recovered signal with the same reconstructed signal passed through an adaptive nonrecursive filter with a linear phase characteristic. Based on this approach, a measurement system structure has been developed to estimate the dynamic measurement error and reduce it by correcting the dynamic characteristics of the sensor and adaptive filtering of measurement noise. A computer simulation of the proposed measurement system for a second-order sensor was performed. Optimal (in the sense of the mean squared deviation of the error) orders of the restoring adaptive filter were obtained in the presence of additive harmonic noise with variable frequency at the sensor output. The properties of the proposed measurement system structure with a dynamic measurement error estimator adaptive to the noise parameter are determined. The application field of the results obtained is the processing of measurement results of rapidly varying processes (including in real time), when the component of the dynamic measurement error caused by the dynamic properties (inertia) of the sensor, as well as the additive noise at its output, is dominant. The solution to such a problem is relevant, for example, when processing the results of ground tests of space technology. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel approach for dynamic micro-vibration measurement, employing an Orbital Angular Momentum (OAM) interferometer, where the reference beam is Gaussian (GS) and the measurement beam is OAM. The OAM light reflected back from the target carries information about the target's vibrations. The interference of the OAM light with Gaussian light generates petal-shaped patterns, and the target's vibration information can be measured by detecting the rotation angle of these petals. Our proposed method demonstrates enhanced tolerance to misalignment and superior precision. The effects of vibration frequency, CCD frame rates, and Topological Charges (TCs) on measurement accuracy are analyzed thoroughly. Experimental results reveal that the proposed method offers a higher accuracy (up to 22.34 nm) and an extended measurement range of (0–800 cm). These capabilities render our technique highly suitable for applications demanding nanometer-scale resolution in various fields, including precision engineering and advanced optical systems. [ABSTRACT FROM AUTHOR]

[Objective] For teaching experiments on the wheelset measurement of rail vehicles, manual measurement is usually conducted with the help of vernier calipers and a fourth type of checker. However, realizing the global dynamic measurement of the tread profile is impossible. Aiming at the issues of low measurement efficiency and poor accuracy in the contact measurement of the wheelset tread surface, this study obtained image information of the wheelset tread surface contour of railroad vehicles using an MV-DP090-02B laser contour sensor. Then, an outlier removal method, composite noise reduction, and feature extraction of three-dimensional (3D) point cloud data were proposed to realize the 3D reconstruction of the tread profile. [Methods] This study designed a measurement experimental device that performs the dynamic measurement of the wheel tread. Then, 3D point cloud data of the tread profile were obtained during low-speed rotation based on the laser triangulation method. Point cloud data processing was conducted in the following manner: 1) Statistical filtering was used to remove the obviously sparsely distributed outliers in the point cloud. 2) Composite filtering was used: median filtering to remove impulses and scanning noise, followed by Gaussian filtering to suppress Gaussian noise. 3) Cubic spline interpolation was used to smooth the pointclouds and restore the tread contour. 4) Geometric features were extracted, and tread contours were reconstructed. [Results] The experimental results showed the following: 1) After obtaining the original point cloud data of the tread profile using the laser profile sensor, the dynamic measurement of the tread profile was realized by combining the outlier rejection and the composite filter noise reduction processing. Compared with the traditional wheelset tread test, the operation was simpler and could be applied to the global measurement of the wheelset tread profile experiment in the course "Mechanical Overhaul of Railway Vehicles." 2) By removing outliers, filtering, and cubic spline interpolation on the original point cloud data obtained from the laser contour sensor and conducting 3D morphological modeling, the true profile of the tread in the entire region could be obtained. 3) The contour data in the dynamic measurement experiment of wheelset tread showed that the maximum relative error of the measurement results obtained using laser contour sensors and related data processing methods did not exceed 5.49%, the average relative error was less than or equal to 2.97%, and the absolute error was less than or equal to 1.01 mm. [Conclusions] The MV-DP090-02B laser profile sensor not only meets the demand of dynamic real-time sweep measurement of wear tread in the experiment but is also easy to operate. The method proposed in this study can greatly improve the measurement accuracy and efficiency and provides a new method of obtaining the tread profile of the wheelset in the experiment of the course "Mechanical Overhaul of Railway Vehicle." [ABSTRACT FROM AUTHOR]

Traditional conductivity method for measuring the liquid-holding of gas-liquid two-phase flow is often affected by the flow pattern and salinity, resulting in reduced measurement accuracy and range. To overcome these limitations, a method for measuring liquid holdup using a reciprocating dynamic conductivity probe under forced annular flow conditions has been proposed. The measurement device consists of a cyclone, conductivity probe, automatic probe reciprocating system, and data acquisition and processing system. On the one hand, this measurement method adjusts the flow pattern to a forced annular flow, so that the measurement results are not affected by the complex and variable gas-liquid flow patterns. On the other hand, the thickness of the liquid film is determined solely based on the circuit's on-off, without relying on the specific conductivity, thus overcoming the influence of mineralization on the measurement results. Numerical simulations were used to determine that the dynamic conductivity sensor should be located approximately 6D downstream of the swirl generator for measuring the liquid film, in which D is the measurement of the inner diameter of the pipe section. Laboratory experiments were conducted to verify the feasibility of the device, and the results show that within the experimental parameter range of gas phase superficial velocities of 5 ~ 20 m/ s and liquid phase superficial velocities of 0. 079 ~ 0. 48 m/ s, the maximum deviation of liquid holdup is 10. 45% . [ABSTRACT FROM AUTHOR]

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Hot forming is an effective approach for improving the formability of ultrathin metal sheets, such as those made of stainless steel and pure titanium. However, the increased friction coefficient between the tool and the high-temperature metal sheet negatively affects material flow during hot forming, potentially resulting in severe local thinning or even cracking. This study explores the frictional behavior of 0.1 mm thick ferritic stainless steel (FSS) and commercially pure titanium (CP-Ti) sheets at elevated temperatures. A friction testing apparatus was developed to measure the friction coefficients of these metal sheets from room temperature (25 °C) up to 600 °C. The friction coefficient of the FSS sheet increased monotonically with temperature, whereas that of the CP-Ti sheet first increased and then decreased. Post-friction testing microscopic examination demonstrated that built-up edges formed on the surfaces of the friction blocks when rubbed against the stainless steel, contributing to the higher friction coefficients. This study provides a foundation for understanding frictional behavior during the hot forming of ultrathin metal sheets.

The use of information technology in classroom teaching has become a common trend. This paper proposes a mathematical model for the dynamic measurement of the level of informatization of Korean language education, which adopts a mathematical logic method to comprehensively examine the attributes, functions, and values of each part of the construction of informatization of Korean language education, and dynamically regulate the relationship between the whole and the parts. The index value of the assessment system is obtained by the weighted average of the factor loading coefficients of each index variable, and the weighting coefficients are determined by the difference assignment method to maximize the differences between the objects being assessed. Finally, the differences in informatization of Korean language education in colleges and universities are measured through the concentrated trend, discrete degree, skewed and peak indicators, and the optimization path is proposed. The results show that the differences in the level of informatization of Korean language education in colleges and universities between regions are all less than 0.1, and the degree of contribution to the total difference is all around 15%, which indicates a relatively small situation of differences between colleges and universities in each region. In this paper, the in-depth measurement of the difference in the level of informatization of Korean language education among Chinese universities in various regions is of great value and significance in promoting the development of Korean language education informatization in Chinese universities.

Herein, a single-camera stereo digital image correlation (DIC) method is developed for dynamic deformation measurement, and a dual-biprism high-speed stereo camera system is proposed to capture surface images. Then, full-field displacement and strain distributions are obtained after correlation and differential calculation using the stereo-DIC algorithm. After a typical experiment is performed to verify the accuracy of the proposed system, full-field displacement and strain distributions of sandwich panels subjected to low-velocity impacts are determined. These results show that the proposed system is an efficient and convenient tool for dynamic deformation measurement.

The R-Test measures the three-dimensional displacement of a tool center point with respect to a work table in five-axis machine tool, as linear axes are driven synchronously with a rotary axis. This paper experimentally compares the measuring performance of the R-Test instruments with (1) tactile linear displacement sensors, (2) laser displacement sensors based on the refraction in a glass ball lens (Laser R-Test), and (3) laser interferometers, in dynamic tests described in ISO 10791-6:2014. A tactile displacement sensor pushes its measuring contact to the target surface by a spring, and its stiffness can limit the measurement bandwidth. This paper experimentally investigates this influence in the measurement of dynamic synchronization error of rotary and linear axes particularly near the reversal point in the present tests. This paper also presents a test to measure the bandwidth of a tactile displacement sensor. [ABSTRACT FROM AUTHOR]

After more than 30 years of development, the measurement performance of atom gravimeters in the laboratory has reached a high level. More and more compact, small, portable instruments begin to appear, and field measurements have been conducted gradually. At present, the field measurements of atom gravimeters are mostly static or "stop-and-go" quasi-dynamic experiments, and the research on dynamic measurement is still in its infancy. High-precision absolute gravity dynamic surveying in the field has shown attractive prospects in many aspects, and many researchers have carried out research on it. This paper first reviews the main research work of the atom gravimeter, especially its dynamic measurement technology. Then it introduces the reported principle, scheme, and equipment of atom gravimeter dynamic measurement. The generation mechanism and suppression methods of the main error sources of dynamic measurement, such as vibration noise, accelerometer drift, and carrier dynamic effect, are analyzed. Finally, the application prospects of atom gravimeter dynamic measurement technology in gravity field mapping, navigation, and underwater target detection are discussed. [ABSTRACT FROM AUTHOR]

The measurement process of ground shock wave overpressure is influenced by complex field conditions, leading to notable errors in peak measurements. This study introduces a novel pressure measurement model that utilizes the Rankine−Hugoniot relation and an equilateral ternary array. The research delves into examining the influence of three key parameters (array size, shock wave incidence angle, and velocity) on the precision of pressure measurement through detailed simulations. The accuracy is compared with that of a dual-sensor array under the same conditions. Static explosion tests were conducted using bare charges of 0.3 kg and 3 kg TNT to verify the numerical simulation results. The findings indicate that the equilateral ternary array shock wave pressure measurement method demonstrates a strong anti-interference capability. It effectively reduces the peak overpressure error measured directly by the shock wave pressure sensor from 17.73% to 1.25% in the test environment. Furthermore, this method allows for velocity-based measurement of shock wave overpressure peaks in all propagation direction, with a maximum measurement error of 3.59% for shock wave overpressure peaks ≤ 9.08 MPa.

The accuracy and efficacy of medical treatment would be greatly improved by the continuous and real-time monitoring of protein biomarkers. Identification of cancer biomarkers in patients with solid malignant tumors is receiving increasing attention. Existing techniques for detecting cancer proteins, such as the enzyme-linked immunosorbent assay, require a lot of work, are not multiplexed, and only allow for single-time point observations. In order to get one step closer to clinical usage, a dynamic platform for biosensing the cancer biomarker CD44 using a single-mode optical fiber-based ball resonator biosensor was designed, constructed and evaluated in this work. The main novelty of the work is an in-depth study of the capability of an in-house fabricated optical fiber biosensor for in situ detection of a cancer biomarker (CD44 protein) by conducting several types of experiments. The main results of the work are as follows: (1) Calibration of the fabricated fiber-optic ball resonator sensors in both static and dynamic conditions showed similar sensitivity to the refractive index change demonstrating its usefulness as a biosensing platform for dynamic measurements; (2) The fabricated sensors were shown to be insensitive to pressure changes further confirming their utility as an in situ sensor; (3) The sensor’s packaging and placement were optimized to create a better environment for the fabricated ball resonator’s performance in blood-mimicking environment; (4) Incubating increasing protein concentrations with antibody-functionalized sensor resulted in nearly instantaneous signal change indicating a femtomolar detection limit in a dynamic range from 7.1 aM to 16.7 nM; (5) The consistency of the obtained signal change was confirmed by repeatability studies; (6) Specificity experiments conducted under dynamic conditions demonstrated that the biosensors are highly selective to the targeted protein; (7) Surface morphology studies by AFM measurements further confirm the biosensor’s exceptional sensitivity by revealing a considerable shift in height but no change in surface roughness after detection. The biosensor’s ability to analyze clinically relevant proteins in real time with high sensitivity offers an advancement in the detection and monitoring of malignant tumors, hence improving patient diagnosis and health status surveillance.

Cantilever vibration in an optical lever AFM is theoretically analyzed considering the effect of surface force and ambient fluid. The surface force between the tip and the sample is modeled using a cantilever with a spring and damping added to the tip, and the effect of ambient fluid on the cantilever vibration is analyzed using the bead model. The amplitude ratios of the forced vibration were derived by solving the equation of motion. There are discrepancies between the amplitude ratio derived from bending vibration theory and that obtained through the optical lever method. The amplitude ratio from bending vibration theory reveals that the effect of surface force dominates primarily below the second resonant frequency. The tip-added spring affects the resonant frequency shift and amplitude ratio, while the tip-added damping mainly affects the amplitude ratio at the resonant frequency. In contrast, the amplitude ratio considering the optical lever method reveals that anti-resonance occurs when the tip-added spring constant is positive, which is not observed in bending vibration theory. The amplitude ratio of the cantilever is modified by introducing a correction factor. The correction factor decreases with excitation frequency except for the frequency where the anti-resonance occurs. The correction factor becomes small when the ambient fluid has high density and viscosity.

The wear condition of steel rails directly affects the safety of railway operations. Line-structured-light visual measurement technology is used for online measurement of rail wear due to its ability to achieve high-precision dynamic measurements. However, in dynamic measurements, the random deviation of the measurement plane caused by the vibration of the railcar results in changes in the actual measured rail profile relative to its cross-sectional profile, ultimately leading to measurement deviations. To address these issues, this paper proposes a method for three-dimensional measurement of steel rail cross-sectional profiles based on binocular line-structured light. Firstly, calibrated dual cameras are used to simultaneously capture the profiles of both sides of the steel rail in the same world coordinate system, forming the complete rail profile. Then, considering that the wear at the rail waist is zero in actual operation, the coordinate of the circle center on both sides of the rail waist are connected to form feature vectors. The measured steel rail profile is aligned with the corresponding feature vectors of the standard steel rail model to achieve initial registration; next, the rail profile that has completed the preliminary matching is accurately matched with the target model based on the iterative closest point (ICP) algorithm. Finally, by comparing the projected complete rail profile onto the rail cross-sectional plane with the standard 3D rail model, the amount of wear on the railhead can be obtained. The experimental results indicate that the proposed line-structured-light measurement method for the complete rail profile, when compared to the measurements obtained from the rail wear gauge, exhibits smaller mean absolute deviation (MAD) and root mean square error (RMSE) for both the vertical and lateral dimensions. The MAD values for the vertical and lateral measurements are 0.009 mm and 0.039 mm, respectively, while the RMSE values are 0.011 mm and 0.048 mm. The MAD and RMSE values for the vertical and lateral wear measurements are lower than those obtained using the standard two-dimensional rail profile measurement method. Furthermore, it effectively eliminates the impact of vibrations during the dynamic measurement process, showcasing its practical engineering application value. [ABSTRACT FROM AUTHOR]

In this study, a more efficient, convenient, and cost-effective way was proposed to design and fabricate a polydimethylsiloxane (PDMS) microfluidic device using 3D printing and transfer techniques. Typically, sensor measurements can only be conducted by immersing the sensor in a solution under static conditions. However, in this study, a newly designed microfluidic device combined with a microfluidic system enables dynamic measurements with sensors. By controlling the flow and temperature of the test liquid, the physiological environment of the human body under various conditions can be simulated, resulting in more accurate and realistic data. During the dynamic condition, an average sensitivity of 6.396 mV/(mg/dL) and linearity of 0.999 were obtained at a flow rate of $75.0 \mu \text{L}$ /min. When the temperature was at 37°C, the biosensor achieved an average sensitivity of 4.381 mV/(mg/dL) and a linearity of 0.999. The dynamic response time was 7 seconds, and the drift rate was 1.47 mV/hr. The experimental results obtained under dynamic conditions showed a significant improvement in the sensing characteristics of the urea biosensor compared with the results obtained under static conditions.

The authors of this paper first proposed the concept, definition and academic connotation of privacy computing, and formed a relatively mature theoretical and technical system accordingly.In order to continuously promote the academic research and industrial application of privacy computing, the academic connotation of privacy computing was elaborated, including how to understand the full-life cycle, extended control, privacy quantification and mapping, desensitization effect evaluation.Besides, the necessity of iterative on-demand desensitization and the motivation to study the language of privacy computing were presented.The role of audit log self-storage in ubiquitous sharing was explained and some distorted academic concepts were also clarified.Moreover, 37 research points in 9 aspects of privacy computing and 40 research points in 8 aspects of data security were given.It helps to better understand the research scope of privacy computing and correctly distinguish between privacy computing and data security.

Dynamic compensation is the (partial) correction of the measurement signals for the effects due to bandwidth limitations of measurement systems and constitutes a research topic in dynamic measurement. The dynamic compensation of an accelerometer is here considered, as obtained by a method that directly comes from a general probabilistic model of the measurement process. Although the application of the method is simple, the analytical development of the corresponding compensation filter is quite complex and had been previously developed only for first-order systems, whilst here a second-order system is considered, thus moving from a scalar to a vector problem. The effectiveness of the method has been tested both through simulation and by a dedicated experiment. Both tests have shown the capability of the method of significantly improve the performance of the measurement system when dynamic effects are more prevalent than additive observation noise. [ABSTRACT FROM AUTHOR]

Dynamic Measurement Modeling (DMM) is a recently-developed measurement framework for gauging developing constructs (e.g., learning capacity) that conventional single-timepoint tests cannot assess. The current project developed a person-specific DMM Trajectory Deviance Index (TDI) that captures the aberrance of an individual's growth from the model-implied trajectory. Four TDI candidates were formulated, and two simulation studies were conducted to investigate the distributional properties and effectiveness of those four TDI candidates. Consequently, the best functioning index was determined as the final formulation of the TDI, to be recommended for use in DMM research. The data generation model in the simulation study was based on the parameter estimates from the Technology-enhanced, Research-based, Instruction, Assessment, and professional Development (TRIAD) cluster-randomized experiment data, which contains seven waves of mathematics test scores for students from preschool through Grade 5, and which has been modeled by DMM in previous research. In addition, an empirical study was also conducted to demonstrate the uses of the developed TDI within those real-world data. Incorporating TDI into DMM analysis strengthened the validity of score use and interpretation and offered a quantitative means of determining which students in the dataset were not adequately served by the dynamic measurement model. [ABSTRACT FROM AUTHOR]

In this study, we introduce a novel approach for dynamic micro-vibration measurement, employing an Orbital Angular Momentum (OAM) interferometer, where the reference beam is Gaussian (GS) and the measurement beam is OAM. The OAM light reflected back from the target carries information about the target’s vibrations. The interference of the OAM light with Gaussian light generates petal-shaped patterns, and the target’s vibration information can be measured by detecting the rotation angle of these petals. Our proposed method demonstrates enhanced tolerance to misalignment and superior precision. The effects of vibration frequency, CCD frame rates, and Topological Charges (TCs) on measurement accuracy are analyzed thoroughly. Experimental results reveal that the proposed method offers a higher accuracy (up to 22.34 nm) and an extended measurement range of (0–800 cm). These capabilities render our technique highly suitable for applications demanding nanometer-scale resolution in various fields, including precision engineering and advanced optical systems.

Tracking operating trains and identifying illegal intruders are two important and critical issues in subway safety management. One challenge is to find a reliable methodology that would enable these two needs to be addressed with high sensitivity and spatial resolution over a long-distance range. This paper proposes a novel monitoring approach based on distributed vibration, which is suitable for both train tracking and incursion detection. For an actual subway system, ultra-weak fiber Bragg grating (FBG) sensing technology was applied to collect the distributed vibration responses from moving trains and intruders. The monitoring data from the subway operation stage were directly utilized to evaluate the feasibility of the proposed method for tracking trains. Moreover, a field simulation experiment was performed to validate the possibility of detecting human intrusion. The results showed that the diagonal signal pattern in the distributed vibration response can be used to reveal the location and speed of the moving loads (e.g., train and intruders). Other train parameters, such as length and the number of compartments, can also be obtained from the vibration responses through cross-correlation and envelope processing. Experimental results in the time and frequency domains within the selected intrusion range indicated that the proposed method can distinguish designed intrusion cases in terms of strength and mode.

It is challenging for engineers to timely identify illegal ground intrusions in underground systems such as subways. In order toprevent the catastrophic collapse of subway tunnels from intrusion events, this paper investigated the capability of detecting the ground intrusion of underground structures based on dynamic measurement of distributed fiber optic sensing. For an actual subway tunnel monitored by the ultra-weak fiber optic Bragg grating (FBG)sensing fiber with a spatial resolution of five meters, a simulated experiment of the ground intrusion along the selected path was designed and implemented, in which a hydraulic excavator was chosen to exert intrusion perturbations with different strengths and modes at five selected intrusion sites. For each intrusion place, the distributed vibration responses of sensing fibers mounted on the tunnel wall and the track bed were detected to identify the occurrence and characteristics of the intrusion event simulated by the discrete and continuous pulses of the excavator under two loading postures. By checking the on-site records of critical moments in the intrusion process, the proposed detection approach based on distributed structural vibration responses for the ground intrusion can detect the occurrence of intrusion events, locate the intrusion ground area, and distinguish intrusion strength and typical perturbation modes.

This article reviews the publications on the theory of dynamic measurements. The problem of minimizing the dynamic measurement error, whose components are due to the dynamic properties (inertia) of the sensor and additive noise at its output, is discussed. To solve this problem, a method is proposed for minimizing the dynamic measurement error as a result of the simultaneous correction of the specified components, and the structure of the measurement system is developed. The measurement system evaluates the dynamic measurement error and reduces it through a simultaneous restoration and filtering of the input measured signal of the sensor. The structure of a special filter with the preliminary correction of the transfer function of the sensor for the further processing of the measured signal is proposed. The processing of the dynamic measurement error consists of the iterative application of a finite impulse restoring filter (or nonrecursive filter) and estimation of the dynamic error. The computer simulation of the developed measurement system was performed for the second-order sensor. The optimal (in terms of the minimum estimate of the dynamic error) values of the order of the restoring filter for the input signals of various types in the presence of an additive Gaussian noise at the sensor output were obtained. The reduction of the dynamic error with the use of the developed measurement system is demonstrated. The obtained results can be used in measuring the parameters of rapidly varying processes when the dynamic component of the error is dominant, which is due to the dynamic properties (inertia) of the sensor and additive noise at its output. [ABSTRACT FROM AUTHOR]

The laser tracker has characteristics of high measurement accuracy and wide measurement range. Laser tracker technology, as an effectively large-scale measuring approach, plays a critical role in dynamic measurement. Currently, the static performance of laser trackers has been well studied. However, the dynamic characteristics of the laser tracker remain unclear in terms of evaluating its dynamic performance. The circular trajectory generator measurement system can quantify the dynamic performance of the laser tracker. We developed a standard circular trajectory generator using a stable servo system and then conducted an in-depth study on the dynamic performance of the laser tracker through statistical analysis. Numerous experiments have shown that if the laser tracker is set at equal spacing, the dynamic indication error is smallest when the measurement distance is 3 m, indicating that the fitted diameter at a distance of 3 m is closest to the diameter of the circular trajectory generator. If the laser tracker is set with equal sampling frequency, the dynamic indication error is smallest when the measurement distance is 5 m. When the circular trajectory generator is at low speed, the measurement spacing of sampling points of the laser tracker is fixed proportional to the number of measurement points, while at low or high speed the sampling frequency of the laser tracker is fixed proportionally to the number of measurement points. These conclusions will facilitate the application of the laser tracker in dynamic measurement. [ABSTRACT FROM AUTHOR]

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Broadband wavelength-swept lasers (WSLs) are widely used as light sources in biophotonics and optical fiber sensors. Herein, we present a polygonal mirror scanning wavelength filter (PMSWF)-based broadband WSL using two semiconductor optical amplifiers (SOAs) with different center wavelengths as the gain medium. The 10-dB bandwidth of the wavelength scanning range with 3.6 kHz scanning frequency was approximately 223 nm, from 1129 nm to 1352 nm. When the scanning frequency of the WSL was increased, the intensity and bandwidth decreased. The main reason for this is that the laser oscillation time becomes insufficient as the scanning frequency increases. We analyzed the intensity and bandwidth decrease according to the increase in the scanning frequency in the WSL through the concept of saturation limit frequency. In addition, optical alignment is important for realizing broadband WSLs. The optimal condition can be determined by analyzing the beam alignment according to the position of the diffraction grating and the lenses in the PMSWF. This broadband WSL is specially expected to be used as a light source in broadband distributed dynamic FBG fiber-optic sensors. [ABSTRACT FROM AUTHOR]

During drilling, a rotary steerable system (RSS) is affected by vibration, rotation, and other random noises. This paper presents a random weighting adaptive estimation of model errors on attitude measurement for RSS drilling tools. The algorithm is used to estimate the covariance matrix of the dynamic model errors and the state prediction vectors for RSS drilling tools, to reduce the effect of abnormal noises of the dynamic model on the estimation of state parameters. The random weighting estimation of observation’s systematic error and covariance matrices of observation error vectors to control the effect of observation model noises anomaly on state parameter estimation, enhance the use efficiency of the latest observation information, indirectly weaken the impact of model error on state parameter vector, and improve the accuracy of attitude calculation of RSS drilling tools. Experimental results and comparison analysis demonstrate that the proposed algorithm achieves better outcomes than the Kalman filtering and Extended Kalman filtering. The maximum solution error is controlled at 0.15°, and the tool face angle error is less than 3°. It cannot only control the covariance matrix of the observation error vector and predicted residual vector, but it can also effectively resist the disturbances of kinematic model error. It also can improve the dynamic measurement accuracy of attitude parameters, and solve the problem of uncertainty in dynamic attitude measurement of RSS drilling tools.

There are arguments about the scattering mechanism of the 10-dB periodic signal fluctuations posed by the repetitive flapping motion in radar ornithology. We design a dynamic measurement system composed of a network analyzer and a high-speed camera to track dynamic radar signals modulated by the flapping gaits of birds within the S-band, X-band, and Ku-band. The results indicate that the respiration motion contributes little to the bird’s signals, but the flapping wings not only contribute at least 10 dB to the signal fluctuation, but also modulate the radar signals of flying birds related to the flapping gaits, regarding different radar bands, observing angles and bird species. Furthermore, the contributions observed in the tests indicate that our theory of the time-varying wingbeat corner reflector (WCR) effect is correct in explaining the modulation mechanism of the 10-dB signal fluctuations in radar ornithology.

For blade tip clearance measurement, the optical measurement method has the characteristics of high precision, anti-electromagnetic interference, and non-contact measurement. A dynamic and high-speed blade tip clearance measurement system based on time stretch dispersive Fourier transform with the optical comb is proposed and demonstrated. The dynamic experiments are designed to verify the accuracy of the system. The results show that the measuring speed is up to 17.6 MHz and the measurement errors are less than 1 μm under dynamic conditions. The experiments prove that the system has the advantages of high measurement accuracy, high speed, and good repeatability. It can provide a new tool for engine health monitoring.

To consider the influence of the quality of the accelerometer and the installation position on the test frequency, a test scheme was designed to identify the first-order bending frequency with free and cantilever beams as well as the first-order torsion frequency with free plates. According to the energy method and mode shape, the correction relationship between the elastic modulus and the first-order bending frequency of free and cantilever beams is derived alongside the relationship between the shear modulus and first-order torsion frequency of a free plate. These relationships are suitable for informing the influence of the accelerometer mass and installation. The first-order bending frequency and the first-order torsion frequency of Sitka spruce beams, slabs, and oriented strand board have been measured along the length, which verifies the effectiveness of the derived relation in testing the elastic modulus and shear modulus of wood materials. Taking the ratio m/M between the mass of the accelerometer and the mass of the test specimen as a parameter, the scope of application of the modified relation is discussed. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study is to investigate the effect of plan complexity on the dosimetry, delivery accuracy, and interplay effect in lung stereotactic body radiation therapy (SBRT) using volumetric modulated arc therapy (VMAT) with 6 MV flattening-filter-free (FFF) beam. Methods: Twenty patients with early stage non-small cell lung cancer were included. For each patient, high-complexity (HC) and low-complexity (LC) three-partial-arc VMAT plans were optimized by adjusting the normal tissue objectives and the maximum monitoring units (MUs) for a Varian TrueBeam linear accelerator (Varian Medical Systems, Palo Alto, CA, USA) using 6 MV FFF beam. The effect of plan complexity was comprehensively evaluated in three aspects: (1) The dosimetric parameters, including CI, D2cm, R50, and dose–volume parameters of organs at risk were compared. (2) The delivery accuracy was assessed by pretreatment quality assurance for two groups of plans. (3) The motion-induced dose deviation was evaluated based on point dose measurements near the tumor center by using a programmable phantom. The standard deviation (SD) and maximum dose difference of five measurements were used to quantify the interplay effect. Results: The dosimetry of HC and LC plans were similar except the CI (1.003 ± 0.032 and 1.026 ± 0.043, p = 0.030) and Dmax to the spinal cord (10.6 ± 3.2 and 9.9 ± 3.0, p = 0.012). The gamma passing rates were significantly higher in LC plans for all arcs (p < 0.001). The SDs of HC and LC plans ranged from 0.5–16.6% and 0.03–2.9%, respectively, under the conditions of one-field, two-field, and three-field delivery for each plan with 0.5, 1, 2, and 3 cm motion amplitudes. The maximum dose differences of HC and LC plans were 34.5% and 9.1%, respectively. Conclusion: For lung VMAT SBRT, LC plans have a higher delivery accuracy and a lower motion-induced dose deviation with similar dosimetry compared with HC plans. [ABSTRACT FROM AUTHOR]

The evaluation of the uncertainty due to systematic dynamic effects is addressed. When high dynamic performance is required, they should be compensated, by solving the associated inverse dynamic problem. When instead they are considered compatible with the target uncertainty, they may be simply included in the uncertainty budget. Furthermore, even in the case of dynamic compensation, a residual uncertainty remains, due to the imperfect compensation, and should be evaluated. Therefore, simple formulas are presented here, applicable to many classes of dynamic phenomena, including periodic, harmonic, transitory impulsive and stochastic stationary ones.

Research in the field of dynamic torque calibration has gained some momentum in the last few years. At PTB, a calibration device for small dynamic torque levels up to about 0.5 N⋅m proved the working principle of dynamic torque calibrations with sinusoidal excitation. In a next step, a new calibration device was developed with the intention of generating higher dynamic torque levels in the range of up to 20 N⋅m. Although this is still less than many industrial applications require, it could pave the way to higher torque levels. The new calibration device features a horizontal arrangement of all components of the drive shaft. The device consists mostly of industrial components that have been modified, rather than custom-made components. After commissioning, optimising the device enabled a frequency range from 10 Hz to up to 400 Hz with dynamic torque amplitudes of up to 20 N⋅m.

After more than 30 years of development, the measurement performance of atom gravimeters in the laboratory has reached a high level. More and more compact, small, portable instruments begin to appear, and field measurements have been conducted gradually. At present, the field measurements of atom gravimeters are mostly static or “stop-and-go” quasi-dynamic experiments, and the research on dynamic measurement is still in its infancy. High-precision absolute gravity dynamic surveying in the field has shown attractive prospects in many aspects, and many researchers have carried out research on it. This paper first reviews the main research work of the atom gravimeter, especially its dynamic measurement technology. Then it introduces the reported principle, scheme, and equipment of atom gravimeter dynamic measurement. The generation mechanism and suppression methods of the main error sources of dynamic measurement, such as vibration noise, accelerometer drift, and carrier dynamic effect, are analyzed. Finally, the application prospects of atom gravimeter dynamic measurement technology in gravity field mapping, navigation, and underwater target detection are discussed.

Tea flow rate is a key indicator in tea production and processing. Due to the small real−time flow of tea leaves on the production line, the noise caused by the transmission system is greater than or close to the real signal of tea leaves. This issue may affect the dynamic measurement accuracy of tea flow. Therefore, a variational mode decomposition combined with a wavelet threshold (VMD−WT) denoising method is proposed to improve the accuracy of tea flow measurement. The denoising method of the tea flow signal based on VMD−WT is established, and the results are compared with WT, VMD, empirical mode decomposition (EMD), and empirical mode decomposition combined with wavelet threshold (EMD−WT). In addition, the dynamic measurement of different tea flow in tea processing is carried out. The result shows that the main noise of tea flow measurement comes from mechanical vibration. The VMD−WT method can effectively remove the noise in the tea dynamic weighing signal, and the denoising performance is better than WT, VMD, EMD, and EMD−WT methods. The average cumulative measurement accuracy of the tea flow signal based on the VMD−WT algorithm is 0.88%, which is 55% higher than that before denoising. This study provides an effective method for dynamic and accurate measurement of tea flow and offers technical support for digital control of the tea processing. [ABSTRACT FROM AUTHOR]