查看更多>>摘要：? 2022 Elsevier LtdAcquiring soil moisture content (SMC) in a mobile way when opening furrows during planting can improve the timeliness of the information to help make planting decision. Common commercial TDR SMC probe sensors was used to discuss the feasibility of applying probe sensors on on-the-go SMC measurement. And a revolving test bench with regulated speed was used to repeatedly conduct dynamic test. The dynamic test results showed common probe sensors can be used for mobile SMC measurement. The optimal measuring attitude of the probe sensor was that the front side of the probe sensor was vertical to soil surface and the probes inclined from the side view (FVSI). When the travel speed was not over 4.8 km/h, the dynamic measured and the static measured after the dynamic test by FVSI owned good correlation. In addition, the movement of the rods of the sensor had relatively stable influence on soil density during the dynamic movement.
查看更多>>摘要：? 2022 Elsevier LtdGeometric circle fitting is a fundamental task in scientific and engineering research. In this contribution, a parameter-free approach for weighted geometric circle fitting is proposed based on the iteratively linearized model with condition equations. Furthermore, the corresponding bias analysis is investigated by the classical theory of nonlinear least-squares. The simulated results show that: 1) Our new approach obtains the optimal solution in various weighted cases and its convergence behavior is more stable than the classical parametric method; 2) The biases caused by nonlinearity can be effectively removed in different situations. Finally, the measured coordinates of an archaeological site in Britain, the Brogar Ring, are adjusted and the results are analyzed.
查看更多>>摘要：? 2022 The AuthorsIn 3D optical metrology, novel approaches to characterise the geometrical quality of gears require a custom gear alignment process to produce reliable results. This study proposes a novel scan alignment method known as subsequent gear alignment (SGA). It emphasises on the proper alignment of the gear hole and follows the alignment of gears in real-world applications. Therefore, the SGA method increases the usability of the previously developed and published methods. The scanned data were first processed with both the commercial global alignment and SGA methods and then evaluated to obtain standard geometrical parameters. These were compared with those obtained by the tactile method, and the SGA method offered improved results over the global alignment method.
查看更多>>摘要：? 2022 Elsevier LtdINRIM realizes its flow rate standard using three distinct facilities, aimed at measuring different flow rate ranges; in particular, for the largest flow range rate (10–2600 L/min) a piston prover is used. This machine is of the volumetric type, therefore its traceability can be obtained through dimensional calibration of the piston, which has a nominal diameter of 1000 mm and a nominal stroke of 1200 mm. The present paper describes in detail the features of the standard, its traceability chain and the uncertainty budget of the measurements it can perform. The uncertainty budget directly determines the Calibration and Measurement Capabilities claim in the range available to the test rig. A detailed analysis of the various uncertainty components will be presented and discussed. Special attention will be dedicated to the dimensional calibration of the piston, since it is of paramount importance for the determination of the main uncertainty component. This calibration is particularly challenging since, due to the large size of the piston, it must be carried on in-situ, thereby requiring a set of special adaptations with respect to a standard calibration of a cylinder. It will be shown that the calibration of the piston recently performed is in good accordance with the one that was carried out at the piston initial installation in 1999, thus confirming the stability of the standard.
查看更多>>摘要：? 2022 Elsevier LtdA focusing polycapillary was incorporated in the M?ssbauer spectrometer to achieve M?ssbauer spectrum from the point with the diameter of 150μm. Since such an apparatus is rather unique and so far it has not been described, a detailed views into the problematics of using the focusing polycapillary with 57Co source, and into the problematics of the scanning transmission M?ssbauer microscope alignment procedure are presented. This article presents the properties of the focusing polycapillary and its performance for 57Fe 14.4keV M?ssbauer radiation using 57Co radioactive source. The performance of the polycapillary is demonstrated with the measurement of the stainless steel. The obtained spectrum exhibited a similar signal to noise ratio as the M?ssbauer spectrum acquired by using a pinhole with the diameter of 200μm. The usage of the polycapillary optics could be a promising way in M?ssbauer spectroscopy, e.g. for measurements of tiny samples in an anvil cell.
查看更多>>摘要：? 2022 Elsevier LtdIn this paper, a co-prime arc array structure with ultrasonic sensors is proposed, and the PM (propagator method) is applied in the field of wind parameters measurement. Two sub-arrays with co-prime properties are stacked to form a co-prime arc array. The array aperture is enlarged which avoids angle blur, improves the measurement accuracy of wind parameters. The propagator method is introduced to keep away from eigenvalue decomposition and estimate wind parameters directly. The estimation variance and CRB (Cramer Rao Bound) of wind parameters are obtained through theoretical analysis and simulation calculation. Simulation results show that the wind parameters measurement method based on co-prime array has lower estimation variance and higher measurement accuracy. A wind parameters measurement system with co-prime arc array was built, and the wind tunnel experiments validated the feasibility of the proposed method.
查看更多>>摘要：? 2022A new formalism using line–line measurements is proposed to improve the accuracy of propagation constant measurement of reflection-asymmetric networks using non-calibrated scattering (S-) parameters. For this measurement, the method uses a reference network with arbitrary forward and backward impedance, propagation constant, and length, thus giving flexibility in the application of line–line methods. S-parameter measurements were carried out for propagation constant extraction of a reflection-asymmetric waveguide loaded with a bianisotropic metamaterial slab made by C-shaped split-ring-resonators using two different kinds of reference networks (two empty waveguide sections as the first kind and the same sections loaded by polyethylene samples as the second kind). It is observed that the standard deviation in the extracted real part of the propagation constant of this network by our method could be reduced by using the first kind of reference network, indicating that the accuracy of our method could be improved using a suitable reference network.
查看更多>>摘要：? 2022 Elsevier LtdWearable and non-contact sensor technologies have spread to many diverse areas with their ease of use and application, and the variety of applications has been increasing rapidly thanks to technological developments in the recent years. This work ensures the usability of wearable and non-contact sensor technologies in various industrial fields. In this study, it is aimed that operators can easily control industrial robots in real-time without the need for a specialized programming environment. For this purpose, a new human–robot interface, in which industrial robots can be controlled by hand movements, has been created. In this interface, Leap Motion Controller (LMC), which uses an IR Camera for the control of robot arm positioning and motion trajectories, and Myo armband, which detects wrist and hand movements with EMG sensors, is used to control of robot end effector (tool) actions. By means of both devices, robot movements are controlled by industrial communication after hand movements, classification and data processing stages. The data processing, control and positioning results of the platform developed in the article are presented in comparison with similar studies in the literature. As a result, it has been observed that the developed platform works with high accuracy. EMG classification success was determined as 96.9% and hand tracking error between 2.45–2.85 mm. Thanks to this new platform, various robotic processes such as pick-place, object movement, painting applications, etc. will be carried out easily and flexibly without the need for programming.
查看更多>>摘要：? 2022 Elsevier LtdAlthough errors-in-variables (EIV) models have been substantially investigated, rank deficient EIV models have not been properly addressed. This paper proves the following major results: (i) given a full EIV model that the elements of its coefficient matrix are continuous random variables with a positive definite variance–covariance matrix, such an EIV model cannot be rank deficient with probability one, indicating that the non-uniqueness condition of total least squares solutions by Golub and van Loan [1] and van Huffel and Vandewalle [2, 3] cannot be true with probability one; (ii) even if a full EIV model is theoretically rank deficient, its rank deficiency cannot be identifiable from measurements with probability one. A full EIV model with theoretical rank deficiency can almost always be incorrectly identified to be an estimable model with probability one, due to the randomness of the coefficient matrix; and (iii) if an EIV model is rank deficient, it must be a partial EIV model, though a partial EIV model is not necessarily rank deficient. Further, if a partial EIV model is rank deficient, we may not numerically obtain its exact rank. These theoretical results have a practical engineering implication that solutions to a rank deficient EIV model from random measurements can be totally incorrect without the notice of an engineer, since there exist an infinite number of mathematically equivalent solutions to such an EIV model. We propose two methods to solve a partial rank deficient EIV model for a unique solution by imposing extra subjective information.
查看更多>>摘要：? 2022For outburst susceptibility assessment of glacial lakes, the accurate extraction of glacial lakes region from satellite image is essential. Several techniques are introduced to extract glacial lakes over the years, such as based on image pixel or different thresholds and object-based statistics. These methods require manual optimization parameters for accurate extraction of the glacial lake's region. Hence, in this work, the deep learning (DL) models are utilized to segment the water and non-water bodies from satellite imagery. DL techniques are successful in many research areas for classification problems, but these techniques are relatively new for the extraction of glacial lakes. The main challenges in implementing DL techniques for the extraction of the glacial lakes are (i) preserving the semantic features of the image without loss during max-pooling operation, (ii) huge dataset requirement for proper training. To overcome the problems mentioned above, a customized architecture of the U-Net named as glacial lakes U-Net (GLU-Net) with various encoders is proposed in this work for effective segmentation of the glacial lakes. The proposed method for segmentation is also compared with the existing DL techniques in this work. The DL models are evaluated on Imja, Chandra, and Bhaga glacier regions datasets collected from Landsat 8 satellite imagery. The average sensitivity (Sen), specificity (Spe), and dice coefficient (Dice) for GLU-Net are 92.23%, 99.81%, and 93.46%. These are the three measures for an average of Imja, Chandra and Bhaga glacier regions. The qualitative and quantitative performance analysis shows the significant improvement of the proposed technique compared to other DL techniques for extraction of glacial lake's region.
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