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In order to improve the positioning accuracy of the traditional master-slave unmanned aerial vehicle (UAV) cooperative navigation algorithm based on range and angle measurement information, given the angle and range measurement errors of low-cost slave UAV measuring equipment, the error model of the cooperative navigation system of master-slave UAV is reconstructed. The navigation and measurement errors of the slave UAV are estimated and compensated. The state equations and measurement equations are derived, then the algorithm is implemented using Kalman filter. Simulation results show that for a slave UAV's inertial navigation system based on a low accuracy micro electromechanical system (MEMS) with a gyro drift level of 10 (°) /h, the root mean square (RMS) of the east and the north velocity errors within 500 s are 0.25 m/s and 0.74 m/s, respectively, and the RMS of the latitude and the longitude errors are 17.10 m and 9.10 m, respectively, under single master UAV combined navigation. The speed accuracy is 3-10 times higher than that of the traditional algorithm, and the position accuracy is about 20 times higher. The positioning accuracy is close to the level of master UAV under double mater UAVs' measurement references. The estimation accuracy of range measurement errors of the slave UAV is high, while the estimation accuracy of angle measurement errors is affected by the heading accuracy of the slave UAV itself. The estimation accuracy of angle measurement error can be further improved if heading references such as magnetic heading exist. [ABSTRACT FROM AUTHOR]

Radar system error registration is a prerequisite and foundation for radar networking. For radars with long detection distances, their measurement errors in the detection space exhibit obvious non-uniform distribution characteristics, which causes traditional system error correction methods to be difficult to solve the error correction problem. In response to the non-uniform distribution characteristics of radar system errors, this paper proposes to divide the radar detection space into several small intervals, in each of which the system errors can be considered as a fixed value. At this time, the iterative closest point algorithm can be used to calculate the radar system error in each interval, and finally a system error compensation matrix is formed for the entire detection space, thereby achieving accurate correction of non-uniform distribution system errors. The effectiveness of the proposed method is verified by the experimental data. [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.)

Copyright of Psychological Science is the property of Psychological Science Editorial Office 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 Steel Pipe is the property of Steel Pipe Magazine 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 Forensic Science & Technology is the property of Institute of Forensic Science, Ministry of Public Security 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 Journal of East China Jiaotong University is the property of Journal of East China Jiaotong University Editorial Office 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.)

Traditional water pipe settlement meters mainly measure water levels through pressure sensors to calculate the settlement within the dam. However, it has the problem of poor measurement stability. To address these shortcomings, a water level measurement method for water pipe settlement meters based on deep learning is proposed. This technology includes a specially designed water gauge and corresponding algorithms. The method involves segmenting the water gauge from top to bottom using a camera and selecting the image containing the water level line. A QR code is used to correct the angle of the image and separate the water gauge, simultaneously, and centimeter-level water level coordinates are obtained. Based on the UNet model, an image matting model is used to accurately segment the water level. Finally, a YOLOv5 model is employed to identify millimeter-level coordinates on the gauge. Experimental results demonstrate that this technology has strong environmental adaptability. The measurement error is less than 0.3 mm compared to manual readings, meeting the requirements of practical engineering applications. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Drainage & Irrigation Machinery Engineering / Paiguan Jixie Gongcheng Xuebao is the property of Editorial Department of Drainage & Irrigation Machinery Engineering 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.)

Aiming at the problem that the dust mass measurement of the existing dust monitoring devices in the process of farmland dust monitoring was susceptible to the influence of ambient temperature and humidity, resulting in zero drift and a large measurement error, this study designed a dust monitoring device based on temperature and humidity compensation. The device included temperature and humidity sensors, mass sensor, data acquisition system, etc., which could realize cross-regional, remote, real-time online measurement of dust mass. The zero drift and temperature and humidity data of the four dust monitoring devices collected by the temperature and humidity correlation test showed that the temperature and humidity had a significant correlation with the zero drift of the dust monitoring device (the mean values of |p| were 0.59 and 0.62, respectively),and the correlation between zero drift of the dust monitoring device and absolute humidity was more stable than relative humidity performance, a linear expression of absolute humidity and zero drift of the dust monitoring device was provided, the humidity coefficient of the expression was positively correlated with temperature. When the temperature changed from 40 ℃ to 60 ℃, the single-factor test of the temperature and the output signal of dust monitoring device showed that the zero drift was 65.7 times that of the sensitivity change, zero drift was a key factor affecting the measurement accuracy of dust monitoring device. A compensation model of the zero-point drift dust monitoring device of BP network based on temperature and humidity was established, the experimental results showed that the data fluctuation range of the proposed model was 8.8% lower than that of the basing on temperature-humidity second-order polynomial compensation model, and 60.3% lower than that of the basing on temperature compensation model of BP network. A field measurement experiment was conducted for the dust monitoring device based on temperature and humidity compensation of this paper. The results showed the device in this paper reduces the final measurement error by 57.5% and the fluctuation of measurement results by 34.2% compared to the uncompensated device, effectively reduced the measurement error of dust mass. The research results could provide technical support for the research on online real-time monitoring of farmland dust. [ABSTRACT FROM AUTHOR]

Copyright of Electric Machines & Control / Dianji Yu Kongzhi Xuebao is the property of Electric Machines & Control 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.)

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Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She 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 Piezoelectrics & Acoustooptics is the property of Piezoelectric & Acoustooptic 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 Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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 Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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 Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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 Systems Engineering & Electronics is the property of Journal of Systems Engineering & Electronics Editorial Department 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 China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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.)

Interferometric Synthetic Aperture Radar (InSAR) is a novel method of ground observation, which is widely used in fields such as surface deformation monitoring due to the fact that it is unrestricted of day and night, as well as cloud and rain. However, due to measurement errors, InSAR technology still has some limitations, especially in the densely vegetated southwest mountainous areas. Time series InSAR, such as SBAS-InSAR receives insufficient observation points, making it difficult to carry out deformation monitoring in mountainous areas. In response to the above issues, this paper considers the atmospheric characteristics of the southwest mountainous areas and designs an improved SBAS-InSAR method to optimize the interferometric phase. The Lijiang-Shangrila Railway is an electrified railway connecting Lijiang City and Shangri-La in Diqing Tibetan Autonomous Prefecture in Yunnan Province. It is an important component of the Yunnan Tibet Railway in the Western Railway Network. In order to ensure the safety and stability of the Lijiang-Shangrila Railway and verify the availability of the above method, this paper takes a certain section along the Lijiang-Shangrila Railway as the experimental area, uses archived SAR data to estimate historical surface deformation, calculates the historical time series deformation of the target area for nearly six and a half years (May 16, 2015 to December 10, 2021), and analyzes their influence range, deformation factors, change patterns, and other information. Finally, the improved SBAS InSAR method proposed in this article is compared with conventional InSAR method, which fully demonstrates the superiority of the proposed method. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry 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 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.)

The "three breakthroughs" data is the most important basic information in the reconstruction and expansion of existing normal speed railways, but traditional methods are single point measurements, mainly relying on RTK. Its disadvantages includes slow measurement speed and poor continuity of results, which seriously restrict the progress of the project. To improve measurement efficiency, a "three breakthroughs" workflow was designed based on high-precision and high-efficiency vehicle-mounted mobile measurement technology, including job preparation, data collection, data calculation, and thematic information extraction. Moreover, each link of the homework process was elaborated in detail, and a complete and efficient "three breakthroughs" detection technology scheme was constructed. At the same time, a refined elevation anomaly fitting model for elevation correction of mobile measurement POS trajectory lines was proposed, optimizing the accuracy of elevation measurement. Research shows that the measurement efficiency of the "three breakthroughs" detection method proposed in this paper can reach 30 km/h, and the measurement error in the plane direction is 12 mm. After using the refined elevation anomaly value fitting model, the elevation measurement error is reduced from 30.1 mm to 21.5 mm. The research results indicate that the "three breakthroughs" measurement results obtained based on railway vehicle-mounted mobile measurement technology can meet the measurement accuracy requirements of general speed railways. Compared to traditional methods, the measurement efficiency has significantly improved. [ABSTRACT FROM AUTHOR]

To overcome the difficulties of obtaining the magnetic anomaly data of underwater vehicles and the low calculation precision of existing magnet simulation models, a high-precision hybrid analytical model suitable in both near-field and far-field based on finite element method is introduced. The spatial signature of magnetic anomaly of an underwater vehicle with complex structure is analyzed by the finite element method. Then, an analytical model combined with uniformly-magnetized spheroid and a dipole array is proposed with the numerical results as the convergence goal. This analytical model consists of several parameters, including the number of array elements, the positions of each element, and magnetic moments, which are solved by nonlinear least-square algorithm. The simulation results show that the magnetic anomaly calculated from this model has good consistencies with the numerical solution in full space, giving an average error of 3% at the measurement plane. This model could be potentially extended to applications like magnetic field continuation and high-precision modeling. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Tiangong University is the property of Journal of Tianjin Polytechnic University 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.)

In order to solve the problem of underwater in-situ measurement of fuel assembly bending and twisting deformation, an underwater in-situ deformation measurement method of fuel assembly based on line laser 3D vision is proposed. The calibration of single-layer refraction-based underwater camera and plane-constrained optical plane calibration algorithms are used to solve the calibration problem of single measurement unit; ten groups of measurement units based on three-dimensional calibration tooling are quickly calibrated in situ to solve the problem of global coordinate unification of the measurement system and the bending and torsion accuracy of the calibration tooling is measured by laser tracking instrument or the comparative experimental verification of the measurement accuracy. The study shows that the developed underwater n-situ deformation measurement system for fuel assemblies based on line laser 3D vision has an error limit of 0.15° for twist measurement and 0.3 mm for bending measurement, and the whole measurement time is about 1 s, which is better than that of the existing measurement system in terms of the measurement efficiency and measurement error limit. [ABSTRACT FROM AUTHOR]

For calibrating the measurement error of the speed sensor and estimating the speed accurately while system is nonlinear and noise is non-Gaussian, dual radar and wheel axle sensor are configured and federal particle filter is used to acquire fusion. The whole operation process of CRH3 train from start to stop between two stations is taken as an example, the speed measurement errors of different speed estimation methods under the conditions of train idling, slipping, vibration and the speed sensor with dynamic noise are analyzed and verified. The simulation results show that: The root-mean-square error can be reduced by 31.52% and 47.35% respectively in the idling and sliding stages after the calibration of dual-radar and wheel-axle combination compared with no calibration; Compared with the two types of dual-radar calibration methods, the maximum relative error of the dual-radar separation vibration speed calibration method can be 39.66% lower than that of the dual-radar angle deviation estimation calibration method when the train vibration speed ratio is 0 to 1 and the radar installation angle error is -1° to 1°. Compared with the filtering results of dual radar and axle sensors before fusion, the speed measurement results after using joint particle filtering fusion are 34.71% and 14.03% lower in MAE, and 26.51% and 10.98% lower in RMSE respectively. Compared with federated extended Kalman filter fusion, the root mean square error of velocity measurement using federated particle filter fusion is 26.97% lower and the maximum absolute error can be reduced by 16.10%. [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]

Copyright of Journal of Remote Sensing is the property of Editorial Office of Journal of Remote Sensing & Science Publishing Co. 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.)

[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]

To confront the difficulties for moving vehicles in measuring the actual heights at various highway height limit facilities, this paper proposes a binocular camera height limit target real-time monitoring algorithm. First, an analysis of the height limit scenarios and facilities is made and a large- scale multi-scenario highway height limit dataset is built. Second, the target region is obtained by the detection and tracking algorithm based on deep learning. The binocular disparity is processed by a multi-step and multi-scale filtering algorithm to obtain the high-confidence height limit facility disparity data and thus calculate the distance and height information. Finally, the robust output strategy is adopted and alarms will be activated based on the real-time collected distance and height results. After multi-scenario height limit experiments, the target detection accuracy stands at 98.77%, the missed detection rateat 0. 87%, the false detection rate at 0. 36%, and the average height measurement error within 60 m below 4%. The results show that our algorithm achieves automatic detection and computation of highway height limit targets, as well as real-time and robust delivery of distance and height measurements and early warnings. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Test & Measurement Technology is the property of Publishing Center of North University of China 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 Journal of Test & Measurement Technology is the property of Publishing Center of North University of China 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 Telecommunication Engineering is the property of Telecommunication Engineering 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 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.)

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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.)

Aiming at the inherent defect of single jammer against synthetic aperture radar (SAR) system with ground moving target indication (GMTI), this defect is usually solved by using the idea of dual-jammer cooperative jamming. However, the jamming methods of dual-jammer cooperative jamming in the current public literature need to reconnoitre some key parameters of SAR-GMTI system in advance, such as the carrier platform speed, the nearest slant distance between the jammer and the carrier platform, and the self-position of the two jammers. The acquisition of these parameters usually requires complex reconnaissance equipment. To solve this problem, an implementation method of dual-jammer system against SAR-GMTI based on integration of reconnaissance and jamming is proposed. This method uses the layout of jammers and receivers as well as the time difference of arrival (TDOA) information between receivers to effectively solve the problem of reconnaissance key parameters of complex equipment, and simplifies the configuration of jamming system. The results show that, considering the measurement error of TDOA and the spacing error of two antennas in SAR-GMTI system, the proposed method can also generate false moving targets with controllable velocity and azimuth position. Theoretical analysis and simulation results verify the feasibility of the proposed method. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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 Journal of Test & Measurement Technology is the property of Publishing Center of North University of China 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 Rolling Stock (1002-7602) is the property of Rolling Stock Editorial Office 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.)

Objectives: In the global navigation satellite system (GNSS) /acoustic positioning system, the transducer position needs to be obtained by rotating the GNSS (global navigation satellite system) receiver position through the offset parameter and attitude observation information. The measurement error of the offset parameter will inevitably affect the position of the transducer and thus the positioning accuracy of the seafloor control point. If the offset parameter is taken as unknown to be solved together with the seafloor control point coordinates without considering the priori information of the offset parameters, the problem of unreliable results of the observation equation due to the strong correlation between the parameters. Methods: First, a Bayesian estimation model of GNSS-A was proposed, the influence of offset parameter error on positioning results is analyzed. Second, we derive the correlation between the position parameters and the offset parameters, explain the reasons for the ill-posed observation equation theoretically, and then a Bayesian estimation model based on prior information of offset parameters is established. Results and Conclusions: The result shows that the model can improve the equation's ill-posed problem caused by the strong correlation between the parameters, and can effectively improve the accuracy of the three-dimensional coordinates and offset parameters of the seafloor control points. [ABSTRACT FROM AUTHOR]

Copyright of Ordnance Industry Automation is the property of Editorial Board for Ordnance Industry Automation 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.)

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Biased calibration can often be found in the model parameter calibration using the traditional Gaussian likelihood function (GLF). Particularly, there are measurement errors in the observation data and complex algorithmic structures in the model. The GLF is also limited to capturing the heteroscedastic characteristics of model residuals, leading to the inaccurate calibration in Markov chain Monte Carlo (MCMC). In this study, two modified likelihood functions were introduced: the Gaussian likelihood function with coefficient of variation transformation (GLF-CV), and the Gaussian likelihood function with Box-Cox transformation (GLF-BC). These modified likelihood functions were then incorporated the heteroscedasticity induced by both the observation data and the model structure. A more accurate representation was obtained for the complex characteristics of the model residuals. The performance of the modified likelihood functions was also evaluated to conduct the parameter calibration and uncertainty analysis using the uncertainty ratio (UR). The field experimental data was collected from three ecological sites: Gao Yaoxue Sticky Rice (early-maturing) from 2004 to 2009, Xinghua Wuyu Jing 3 (mid-maturing) from 2001 to 2004, and Liu'an Shanyou 63 (late-maturing) from 1991 to 2004. The RiceGrow and Oryza2000 phenology models were selected to compare the effects of GLF-CV, GLF-BC, and GLF on the calibration. Model parameter calibration was also conducted using the Ensemble Sampling for Affine-invariant MCMC (EMCEE). The research findings were summarized as follows: 1) The UR ranges were 2.66-4.54, and 2.30-4.47 days, respectively, for the RiceGrow and Oryza2000 phenology models under all three likelihood functions. There were some effects of all three likelihood functions on the parameter calibration, leading to reasonable UR values within the specified ranges. 2) The GLF-BC of the RiceGrow model was achieved in the smallest UR values for the Gao Yaoxue Sticky Rice, Xinghua Wuyu Jing 3, and Liu'an Shanyou 63 varieties. Specifically, the predicted UR values with the GLF-BC were 0.09, 0.07, and 0.80 days smaller than those with the GLF, while 1.21, 0.20, and 0.07 days smaller than those with the GLF-CV. The superior adaptability of GLF-BC was then achieved in the RiceGrow phenology model, indicating the better-improved calibration. 3) The likelihood function with the smallest UR varied greatly among the different rice varieties in the Oryza2000 phenology model. The GLF obtained the smallest UR for the Gao Yaoxue Sticky Rice variety, while the GLF-BC and GLF-CV were the smallest UR for the Xinghua Wuyu Jing 3 and Liu'an Shanyou 63 rice varieties, with values of 2.30, 4.17, and 3.50 days, respectively. Consequently, the likelihood function depended mainly on the primary source of heteroscedasticity in the model residuals. The optimal model was achieved in the GLF-CV, when the main source was the observation data, whereas, the GLF-BC was preferred, when the main source was the model structure. The GLF was selected as the suitable likelihood function with the minimal heteroscedasticity of model residuals. In conclusion, the heteroscedastic characteristics of model residuals were captured from the measurement errors and complex algorithmic structures. Two modified likelihood functions (GLF-CV and GLF-BC) can also provide more accurate descriptions of heteroscedasticity induced by both observation data and model structure. The comparative analysis of parameter calibration and model uncertainty with the UR demonstrated that the modified likelihood functions can be expected to effectively improve the calibration. The likelihood function also depended on the main source of heteroscedasticity, with the preferable GLF-CV under the primary source of observation data, and the preferred GLF-BC under the primary source of the model structure. The GLF was suitable for the minimal heteroscedasticity of model residuals. [ABSTRACT FROM AUTHOR]

Copyright of China Mechanical Engineering is the property of Editorial Board of China Mechanical Engineering 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.)

"Determination of calcium content in dolomite by potassium permanganate method" is a classical analytical chemistry experiment to train students' comprehensive experimental ability, including dissolution of dolomite ore sample, preparation and washing of calcium oxalate precipitate, concentration calibration of potassium permanganate solution and titration of calcium oxalate precipitate. Because of the complexity of the experiment process and the many influence factors, it is very difficult that students control the measurement error within 3‰ in the experiment. Therefore, we guide students to precipitate calcium oxalate from acid-dissolved dolomite solution under different experimental conditions, investigate the relationship between the particle size and surface morphology of calcium oxalate precipitate and the determined calcium contents, and thus revealing the control factors affecting the accuracy of calcium content determination. It not only deepens the students' understanding to the experimental process, but also stimulates their interest in learning chemical experiments, improving their experimental ability and strengthening their confidence in scientific research. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Mine Automation is the property of Industry & Mine Automation Editorial Department 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 Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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 Journal of Chongqing University of Technology (Natural Science) is the property of Chongqing University of Technology 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.)