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Detecting insulation performance through testing the Raman spectroscopy of transformer oil is noninvasive and shows great promise in on-site diagnosis. The information, stored in spectra, that may reflect aging states of insulation aims to be effectively unfolded and provides decision support as well. In this article, a transformation method based on intrinsic product arithmetic is used to transform the 1-D Raman spectral data into 2-D image data. With the help of CNN based on the dimensionality expanding method, diagnosis of oil–paper insulation with different aging states based on the Raman spectroscopy was realized. The network-based oil–paper insulation aging diagnosis model has an accuracy of 95% in ten aging categories of 60 test samples and 100% in four aging categories. The result shows the trained CNN was able to identify the differences of transformer oil samples at each aging stage through visualized Raman spectral image. This method provides a more accurate determination method for diagnosing oil-immersed transformers’ aging conditions; it also develops an available method for a more detailed evaluation of insulation aging levels. [ABSTRACT FROM AUTHOR]

Moisture accumulates with the growing aging progress of oil-paper insulation and further shortens the remaining life of the transformer. The frequency-domain spectroscopy (FDS) technique can be used to realize the moisture estimation. However, the moisture estimation results would be unreliable once the aging effect on FDS was ignored. Given this issue, an alternative model including the aging effect is thus proposed using FDS and intelligent algorithm. In this work, the feature parameters of FDS data are used to build the databases for characterizing the aging degree and moisture. Then, the moisture estimation models are developed using the weighted K-nearest neighbor (K-NN) algorithm. The accuracy and applicability of the proposed models are finally discussed in laboratory and field conditions. In that respect, the findings reveal that the reported model is available for moisture estimation of transformer oil-paper insulation under various aging degrees and test temperatures. [ABSTRACT FROM AUTHOR]

The influence of nonuniform aging has not been considered in the prediction of the frequency domain spectroscopy (FDS) of the transformer oil-paper insulation (OPI) when using the finite element method (FEM). Given this issue, the modified simulation model was constructed based on the XY model and FEM. In the current work, the dielectric response property of the pressboards with different aging conditions in the modified model was characterized by its dielectric response parameters measured in the lab. Then the modified simulation model constructed in a 3-D system would be applied to study the effect of both nonuniform aging and the axial geometry on the FDS of OPI. Finally, the feasibility of the proposed models was verified by comparing the measured FDS and the predicted FDS. This article is expected to provide a model for predicting the FDS of the transformer OPI including the effect of nonuniform aging. [ABSTRACT FROM AUTHOR]

Over the last decade, the rapid development in health care industry and security has driven innovations in the field of wearable electronics and smart sensors. This report demonstrates the fabrication of molybdenum diselenide (MoSe2) by a facile, low-cost and scalable hydrothermal synthesis method followed by a vacuum filter deposition on cellulose paper. The fabricated device is utilized as a pressure and strain sensor. The fabricated device is passivated using polydimethylsiloxane (PDMS), and also, PDMS film enhances the flexibility of the device. The calculated sensitivity of pressure sensor is ~0.3 kPa−1, which is comparable and relatively better than the pressure sensor fabricated using sophisticated techniques. Furthermore, the device exhibited significant of merit for strain sensing with a gauge factor of ~6.84. The fabricated device showed excellent resilience in 500 cycle bending tests, which promises the robustness of the device. As an application, the fabricated sensor is used to develop a wireless keyboard by integrating the sensor on fingertips of an individual and a real-time human motion monitoring application in which the data are transmitted wirelessly to a smartphone with a dedicated android application. The successful fabrication of MoSe2/paper-based cost-effective, flexible, and biodegradable pressure-strain sensor shows tremendous applications in future intelligent user interface systems, human security, and personal health care monitoring. [ABSTRACT FROM AUTHOR]

Recycled paper is extensively used worldwide. In the last decades, its market has expanded considerably. The increasing use of recycled paper in papermaking has led to the production of paper containing several types of impurities. Consequently, wastepaper mills are forced to implement quality control schemes for evaluating the incoming wastepaper stock, thus guarantying the specifications of the final product. The main objective of this work is to present a fast and reliable system for identifying different paper types. Therefore, undesirable paper types can be refused, improving the performance of the paper machine and the final quality of the paper manufactured. For this purpose, two fast techniques, i.e., Fourier transform midinfrared (FTIR) and reflectance near infrared (NIR), were applied to acquire the infrared spectra of the paper samples. Next, four processing multivariate methods, i.e., principal component analysis, canonical variate analysis (CVA), extended CVA (ECVA), and support vector machines (SVMs), were employed in the feature-extraction or dimension-reduction stage. Afterward, the k nearest neighbor (kNN) algorithm was used in the classification phase. Experimental results show the usefulness of the proposed methodology and the potential of both FTIR and NIR spectroscopic methods. Using the FTIR spectrum in association with SVM and kNN, the system achieved a maximum classification accuracy of 100%, whereas using the NIR spectrum in association with ECVA or SVM and kNN, the system achieved a maximum classification accuracy of 96.4%. [ABSTRACT FROM PUBLISHER]

This paper presents a digital gyroscope interface system for high-frequency bulk-acoustic-wave (BAW) gyroscopes with in-run automatic mode-matching (AMM) capability. The presented work demonstrates the design and implementation of the dual-mode (DM) operation architecture on a flexible digital platform, which allows for low-cost rapid development and evaluation of new functions and architectures. Two prototype silicon BAW gyroscopes are tested on this platform using the proposed system to verify the advantages of the DM architecture. The AMM in DM showed below 4-ppb mode split accuracy and fast converge time without overshoot or oscillation. The DM operation with in-run AMM substantially reduced the bias drift of the gyros, leading to significantly lower rate random walk (RRW) compared to conventional single-mode (SM) operation. The performance repeatability and stability over the temperature of the DM gyro system are characterized, showing as high as $50\times $ improvement compared to the SM architecture. [ABSTRACT FROM AUTHOR]

We present the development of a novel smart ink pen instrumented with force and motion sensors designed for the quantitative and ecological assessment of daily-life handwriting. This work aims at testing the pen’s sensors and algorithms and the use of the smartpen to detect age-related changes in writing and tremor parameters during daily-life handwriting. A comparison against reference instruments was carried out to validate the pen tip force during static and dynamic conditions, the pen’s tilt angle, and the algorithm for the segmentation of the force signal into strokes. The smartpen was tested on 43 healthy adults divided into three age groups (young, middle-old, and old) during unconstrained handwriting on paper. The validation of the pen’s sensors and algorithms reported excellent results. A solid test–retest reliability was found in the writing and tremor indicators extracted from both young and old adults. As for the age-related analysis, the older age groups were characterized by an increase of temporal writing measures, a more uniform writing pressure, and more repetitive and predictable tremor oscillation components. The greatest accomplishment of our smart ink pen is the ability to combine the advantages of the digitizing tablet technology with the natural “feel,” the ease of use, and the ecological validity of the traditional pen-and-paper approach. The proposed solution represents an important step toward a simple, ecologically valid, reliable quantitative assessment of daily-life handwriting. Our smartpen is particularly suitable for daily-life telemonitoring applications in a number of important health-related fields. [ABSTRACT FROM AUTHOR]

Proposes a study which looks at a decoupled measurement method for sheet basis-weight and ash content. Importance of ash content; Discussion and results of the study.

Dear Readers, since my term as the Editor-in-Chief (EiC) of the IEEE Transactions on Instrumentation and Measurement (TIM) will come to an end by the end of this year, I would like to reflect on the last five years and briefly report the outstanding milestones TIM has achieved thanks to our focus on quality. But before that, let us first go through our traditional annual evaluation of TIM, starting with its quality metrics which continue to impress. [ABSTRACT FROM AUTHOR]

To satisfy the requirement of quality control in printing and packaging industry, a sheet counting apparatus is developed, which adopts a line-scan camera to image the fringes of sheet stack and is able to provide a real-time and noncontact measurement of their quantity. With a brief introduction of the system architecture, our main work focuses on the sheet counting algorithms. The basic principle is to identify each sheet profile from the 1-D image with a robust ridge strength measurement. First, a multiscale bi-Gaussian ridge likelihood measurement and a ridge-valley descriptor are utilized to improve adjacent objects detection by increasing local contrast around sheet fringes. Then, a sheet recognition scheme, which integrates a peak detection algorithm and the ridge region criteria for verification, is proposed to discriminate true sheets from the obtained ridgeness measure. According to experiments and tests in real production lines, our apparatus can reach a very high measuring accuracy for printing papers or cards with a thickness not <0.2 mm. [ABSTRACT FROM PUBLISHER]

An international comparison of lightning and switching impulse voltage measuring systems was arranged and coordinated by the Helsinki University of Technology (MIKES-TKK), Espoo, Finland, between 1999 and 2002. The number of participants was 26, including the coordinator. This paper summarizes the results obtained by those eight National Metrology Institutes that participated in the comparison. A 400-kV transfer reference measuring system for measuring lightning impulse voltages was prepared by the coordinator. In addition, a 1-kV impulse voltage calibrator system, including calibrators for both standard lightning and switching impulses, was circulated. [ABSTRACT FROM AUTHOR]

The 37th IEEE International Instrumentation and Measurement Conference (I2MTC) was planned to be held in Dubrovnik, Croatia, one of the most prominent destinations in the Mediterranean Sea and UNESCO World Heritage site since 1979. I2MTC is the flagship conference of the IEEE Instrumentation and Measurement Society that is dedicated to advances in measurement methodologies, measurement systems, instrumentation, and sensors in all areas of science and technology. The conference has been held every year since 1986 across the globe bringing together academic and industrial communities in discussions on a wide spectrum of research results and developments with applications in current industrial technology. Strong technical programs, accompanying social events, old and newly acquired friends, and life-long education opportunities provide strong reasons to attend the conference every year. [ABSTRACT FROM AUTHOR]

The article focuses on the changes in the Institute of Electrical and Electronics Engineers (IEEE) TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT (TIM) as it transitions to an online-only and volume-only journal in 2021. Topics include the rapid publication of accepted papers with a shortened waiting time, the introduction of 20 high-level topics for paper classification, and the adaptation of Special Issues to Special Sections, such as I2MTC and CPEM.

A wet thermal paper method for measuring of mode patterns and heat distributions in a high-power microwave multimode cavity is developed. The exposure time of the paper is evaluated. It is shown that this method allows measuring and recording mode patterns in the loaded and unloaded cavity, and the heat distribution inside the cavity with a load movement The mode patterns and heat distributions along horizontal and vertical planes of the cavity are presented. Possible applications of the method in medicine and biology are discussed, and a calibration protocol of a microwave oven for microwave radiation exposure on cell cultures in the cavity is given. [ABSTRACT FROM AUTHOR]

This paper proposes a metamaterial inspired radio frequency touchpad sensor system based on two split ring resonators (SRRs) realized on a Rogers/Duroid 5870 with 2.33 dielectric constant = 2.33, loss tangent = 0.0012, and thickness = 0.8 mm. The touchpad consists of two SRRs resonating at $f_{1} = 2.74$ GHz and $f_{2} = 3.86$ GHz. When a finger is placed on SRR 1, $f_{1}$ changes from 2.74 to 2.57 GHz due to electromagnetic coupling between the SRR and the finger, and similarly, $f_{2}$ changes from 3.86 to 3.76 GHz. The proposed touchpad system can detect a finger wearing a glove, in contrast to capacitive touchpads utilized in contemporary smart phones. We demonstrated 56- and 49-MHz frequency shifts for $f_{1}$ and $f_{2}$ , respectively, with 1.66-mm total thickness (0.69-mm-thick photo paper and 0.97-mm-thick glass slide). [ABSTRACT FROM AUTHOR]

The 35th IEEE International Instrumentation and Measurement Technical Conference (I2MTC) was held in Houston, TX, USA, on May 22–25, 2018. I2MTC is the flagship conference of the IEEE Instrumentation and Measurement Society held every year since 1986. It is dedicated to advances in measurement methodologies, measurement systems, instrumentation, and sensors in all areas of science and technology. The I2MTC is proposed as a catalyst to promote interactions between industry and academia; a wide spectrum of academic research results is presented, with potential practical applications in current industrial technology, as well as industry and application-driven developments. [ABSTRACT FROM AUTHOR]

New methods for extending the tunability range in second-order voltage-controlled oscillators (VCOs) with quadrature outputs are presented and compared in this paper. Linear dependence is the most common type of relation between frequency of oscillations (FO) and control voltage (or current) in communication subsystems (VCOs). However, there are other nonlinear types of dependencies that are advantageous (quadratic and cubic) and should be further studied. Positions of controllable blocks within the structure of the oscillator (providing parameters influencing time constants of integrators) in two scenarios are studied together. The impact of controllable parameters of these additional elements on FO as well as on produced output signal levels is evaluated. The simulation and experimental results are shown to confirm expected behavior of solutions in the case of the quadratic type of control of FO. Nowadays, standard linear control offers a tunability ratio 10:1 (for the same ratio of parameters that control the FO) only. However, in this paper, the experimental tests yield a tunability ratio 80:1 (50 kHz–4 MHz) for dc control voltage within the range 0.175–1.75 V (10:1). The presented approach is very beneficial for low supply voltage systems requiring a wide range of tunability and also for utilizing active devices having limited range of adjustability of their controllable parameters while still requiring wide tunability. [ABSTRACT FROM PUBLISHER]

This paper extends prior work on magnetic and inertial sensor frame calibration with an optimization study for the calibration of tilt-compensated electronic compasses. The novelty of this paper consists in formally demonstrating the optimal calibration orientations that maximize the observability of the various calibration coefficients. The optimal orientations are determined by analyzing the partial derivatives of the cost functions with respect to the calibration coefficients, and finding those orientations that produce their maximum slopes. This approach leads to the preservation of the information needed to determine the calibration coefficients by avoiding geometric dilution. Calibration schemes including optimal orientations for the accelerometers and magnetometers are determined not only for the alignment of the magnetometers and accelerometers sensor reference frames but also for the prerequisite calibrations in the sensor reference frames and partial body frames, respectively. This paper also shows that the optimal accelerometer orientations are different from the optimal magnetometer orientations, however, leaves the analysis of a possible compromise to future work. While confirming some intuitions about possible optimal orientations, this paper also offers an insight into those cases not supported by empirical wisdom, such as the misalignments, eliminating therefore the guesswork from the selection of the calibration profiles. [ABSTRACT FROM AUTHOR]

This paper shows the feasibility of the blood analysis based on the electrochemical impedance spectroscopy (EIS) using compact low-cost instrumentations. This paper presents the measurement problem and some models for the interpretation of blood impedance spectra. The requirements for ad-hoc instrumentation are derived, and the implementation of a compact, low-cost, and reliable impedance measurement system operating in the frequency range 1 kHz–2.2 MHz is described, which is an improved version of the one presented in a previous work. To prove the potentialities of the EIS-based blood analysis, some parameters relevant to medical diagnosis such as hematocrit, erythrocyte sedimentation rate, and reactive oxygen species levels in blood are extracted from the impedance spectra measured with the two instruments. The presented results indicate that the application of low-cost compact systems for blood impedance measurements can reduce time and costs of the blood analysis and open new perspectives, especially for point-of-care diagnostics. [ABSTRACT FROM AUTHOR]

Using the barometer for height estimation often requires the use of external reference to correct biases in measurement. These biases are often caused by the change of the ambient pressure environment. The barometric height estimation is especially challenging in tactical and rescue applications where high temperatures or sudden large pressure shocks can change the pressure rapidly. We assess the suitability of barometers for infrastructure-free navigation in tactical applications. First, this paper investigates the effect of transition in seamless indoor/outdoor navigation. Second, we measure the effects of pressure shocks, caused by explosions or firearms, on low-cost and lightweight micro-electromechanical barometers to ensure that the sensors are capable of operating under these conditions. Finally, we investigate the use of sonar measurement to estimate the vertical speed as an alternative to the reference barometer for infrastructure-free navigation. The fusion of barometer and sonar achieved on average 0.46-m root-mean-square error (RMSE) while simple barometric height estimation had a RMSE of 0.65 m. The fusion method had no errors over 1.5 m during the test. This accuracy is generally sufficient to find the correct floor level which is crucial for tactical situational awareness. The goal of this paper is to develop the methods for seamless indoor/outdoor navigation, and therefore the most important result of this paper is that the error caused when transitioning between outdoor and indoor environments is visibly reduced. [ABSTRACT FROM AUTHOR]

This paper has two main objectives. First, it describes the practical challenges of field trials and proposes a developed test method. Second, the test method is used to compare the uplink (UL) performance with different antenna technologies when user equipment (UE) does not have a line of sight (LOS) to the evolved node B. Both passive and active antenna configurations were used in the performance evaluation. Modern cellular networks have high demands for capacity, reliability, and availability. The verification of a network’s configuration and technological features is essential to guarantee network performance, and the performance of a network must be verified by the laboratory testing or field trials; such trials produce the experimental knowledge of technology features and configurations. Technological and environmental factors must also be considered before performing mobile network field testing. This paper showed that moving UE produces more reliable and repeatable results than measurements with stationary UE. Our antenna configuration comparison study revealed that in the UL direction, active antenna system beam control could significantly increase the UL capacity in non-LOS conditions. [ABSTRACT FROM AUTHOR]

An introduction is presented in which editor discusses various articles within the issue on topics including developments in ultra-high accuracy electrical metrology, Planck constant and digital sampling techniques for the measurements of impedance.

This paper presents a novel deep learning-based method that integrates a Convolutional Auto-Encoder (CAE) with support vector machine (SVM) for finger-vein verification. The CAE is used to learn the features from finger-vein images, and the SVM is used to classify finger vein from these learned feature codes. The CAE consists of a finger-vein encoder, which extracts high-level feature representation from raw pixels of the images, and a decoder which outputs reconstruct finger-vein images from high-level feature code. As an effective classifier, SVM is introduced in this paper to classify the feature code which is obtained from CAE. Experiments prove that the proposed deep learning-based approach has superior performance in learning features than traditional method without any prior knowledge, presenting a good potential in the verification of finger vein. [ABSTRACT FROM AUTHOR]

This paper proposes a pattern recognition method for the fault diagnosis of machinery based on an enhanced trace ratio linear discriminant analysis (ETR-LDA) algorithm. It is an extension of TR-LDA that pursues to maximize the between-class distance and minimize the within-class distance. Since TR-LDA focuses on the total between-class distance and ignores the attention to local features, it may lead to deficiencies in the classification of specific patterns/classes, which is defined as short board in this paper. To cope with this limitation, the proposed ETR-LDA makes a reconsideration of the relationship between the total between-class distance and the global separability. More specifically, a new objective function is derived in ETR-LDA by taking the smallest between-class distance into account. The optimal solution of this objective function is proved to improve the smallest between-class distance with no change to the convergence and the global optimality of the algorithm, and the separability of different classes is increased eventually. Both synthetic data and hard disk drive wearing experimental data are employed to verify the efficiency of the proposed method. The results show that ETR-LDA is able to distinguish those fault categories and outperform TR-LDA and other dimensionality reduction methods. [ABSTRACT FROM AUTHOR]

In human–robot coexisting environment, one of the primary objectives is to equip robots with the facilities of detecting and following a human being in front, using various sensors. Within this genre, developing algorithms for vision sensor-based shoe detection and subsequently following is considered an active problem. Considering that the shoe poses, during the pursuit, undergo different transformations, this paper presents how the vision sensor based shoe detection problem can be treated as analogous to template matching under general conditions. This paper first shows how a popular fast randomized template-matching algorithm, called FAsT-Match algorithm, and its contemporary variant for color images, called CFAsT-Match algorithm, can be implemented in real robots with success for detecting shoes in subsequent frames. Then, this paper proposes a new density-based clustering method, called ordering points to identify the clustering structure (OPTICS), based template-matching algorithm that is specifically developed to overcome several implementation problems associated with the FAsT-Match and CFAsT-Match algorithms, in real life. Experimental results and performance evaluations demonstrate the superiority of the proposed OPTICS-based algorithm for shoe detection during human tracking in human–robot coexisting environments. [ABSTRACT FROM AUTHOR]

In this paper, an antenna gain measurement method for millimeter-wave antennas in an on-wafer probe station environment is studied. The one-antenna gain measurement has been known since the 1940s. However, the authors believe that this extension of their previous work is the first time when the method is systematically studied in the on-wafer probe station environment. The main difference between the original one-antenna gain measurement and our method is that in the probe station environment, the space is limited and, therefore, the reflecting plate dimensions are limited. We have studied the effect of the reflector size limitation through computations using physical optics and through measurements with a standard gain horn (SGH) and with a printed microstrip patch antenna. The necessary size of the reflecting plate naturally depends on the beamwidth of the antenna under test and on the distance. Time gating has been applied in the retrieving calculation to filter out multiple reflections. According to this paper, the one-antenna gain measurement in the $W$ -band results in the correct antenna gain with very high accuracy for the highly directional SGH. For the patch antenna, the gain measured in the on-wafer probe station environment agrees well with the simulated one. [ABSTRACT FROM AUTHOR]

While formal and rigorous procedures are adopted to ensure the reliability of measurement results, the decision-making activities based on the information returned by measurement are often poorly structured and based on vague assumptions and reasoning, thus negatively impacting the reliability of the achieved conclusion. To overcome this problem, a structured multicriteria decision-making approach based on the analytic hierarchy process was recently proposed in the literature to properly support decision-making activities by exploiting the information provided by measurement results related to heterogeneous properties and its application was demonstrated in a case study. Using the same case study, this paper analyses the sensitivity of the obtained conclusion to various uncertainty sources that are embedded in that approach. In particular, the impact of uncertainties on both measurement and pairwise comparisons of the criteria is analyzed and their combined effect is evaluated by considering a worst case situation. Moreover, the effect of the formula adopted to aggregate the information returned by the measurement of heterogeneous properties on the final decision is considered. The performed analysis contributes to support a disciplined and methodologically sound implementation of decision-making activities, significantly improving both the repeatability and reproducibility of the whole evaluation process, as well as the confidence in the achieved conclusions. [ABSTRACT FROM AUTHOR]

In this paper, the current distribution of an experimental lead cell is estimated using two methods and the results are compared. Noninvasive measurements are obtained using our magnetic tomography system, consisting of an array of magnetic sensors and a solver algorithm that is specially adapted for application to lead cells. Verification of this magnetic tomography system is achieved by comparing the results with data from a new invasive measurement instrument also reported in this paper. This new instrument is an array of ferrous cored current transducers submerged in the cell electrolyte, providing a direct spatially and temporally resolved measurement of the ionic current in a lead cell. Comparisons between the techniques and data are drawn. The new flowthrough internal sensor array has been designed specifically for this application and represents an improvement over a similar system reported in the literature. In addition, some auxiliary features of the experimental setup are designed to enable useful magnetic measurements to be taken by minimizing the complexity of the setup, and therefore the complexity of the models needed to interpret the data. Example results are presented for a typical automotive lead cell operating at a low state of charge and in a fatigued condition, to demonstrate the ability of both measurement systems to produce spatially and temporally resolved images of current distribution. The methods are evaluated, and the future work is recommended. [ABSTRACT FROM AUTHOR]

An accurate assessment of the damp status of oil-impregnated paper (OIP) bushings is crucial for the power industry to make informed decisions on the maintenance and replacement schedule of bushings. This article proposes a hybrid of the convolutional neural network (CNN) and the hidden Markov model (HMM) for estimating the damp status (i.e., moisture level and moisture source) of bushings especially when nonuniform moisture distribution exhibits in the bushing. First, simulation models of moisture diffusion and frequency-domain spectroscopy (FDS) of the OIP bushing were constructed using the finite element modeling (FEM) approach. Then, CNN was employed to extract informative features from FDS results of the OIP bushing, which is sensitive to both concentrations and sources of moisture. Finally, HMMs were further utilized as a strong stability tool to recognize the damp status of OIP bushings. The proposed method was implemented to identify the bushing damp status using both simulation data and real-life measurements. Identification results demonstrate that the proposed method has high accuracy in determining the moisture level and moisture source of the OIP bushing insulation. [ABSTRACT FROM AUTHOR]

This paper demonstrates the feasibility of implementing real-time state estimators for active distribution networks in field-programmable gate arrays (FPGAs) by presenting an operational prototype. The prototype is based on a linear state estimator that uses synchrophasor measurements from phasor measurement units. The underlying algorithm is the sequential discrete Kalman filter (SDKF), an equivalent formulation of the DKF for the case of uncorrelated measurement noise. In this regard, this paper formally proves the equivalence of SDKF and the DKF, and highlights the suitability of the SDKF for an FPGA implementation by means of a computational complexity analysis. The developed prototype is validated using a case study adapted from the IEEE 34-node distribution test feeder. [ABSTRACT FROM PUBLISHER]

This paper presents a comprehensive investigation of several important error sources for the successive-approximation register (SAR) analog-to-digital converters (ADCs). The error sources that we discuss in this paper include the dynamic comparator offset, the dynamic gain error of digital-to-analog converter (DAC), the capacitor mismatch of capacitive DAC, the incomplete settling of DAC, the undershoot of reference voltage, and the input signal coupling. The integral/differential nonlinearities (INL/DNL) of SAR ADCs that are resulted from these error sources are analyzed and addressed. A diagnostic procedure is presented to identify the possible error sources based on the INL/DNL plots. In addition, design suggestions for overcoming these problems are also offered and recommended in this paper. [ABSTRACT FROM AUTHOR]

Detecting partial discharge (PD) in gas-insulated switchgear (GIS) is an effective way to diagnose the insulation state of GIS. When PD occurs in GIS, optical and electromagnetic signals will be emitted from the discharge source. PD can be detected by analyzing these signals. At present, the ultrahigh-frequency (UHF) method is one of the most popular methods for detecting the PD in GIS. However, the optical method has not been in the field due to the problem of mounting optical sensor into GIS, even though it has higher sensitivity and better anti-interference performance. To settle this problem, a novel GIS PD detection sensor integrated with the optical fiber and UHF method is developed in this paper, which can fully utilize the advantages both of UHF and optical methods. The simulation results indicate that the integrated sensor can be mounted into GIS on the premise of not affecting the electric field distribution in GIS. In addition, the integrated sensor has a good UHF performance. The PD signals of typical defects at several locations were measured in a physical GIS using the integrated sensor. The results show that the integrated sensor can detect the optical and UHF signals induced by PD at the same time. The optical method has higher sensitivity than the UHF method for the protrusion defect. The amplitude and the number of the optical signals induced by PD clearly decrease with the increase in the detection distance. The studies in this paper are helpful to improve the accuracy and sensitivity of PD detection in GIS on site. [ABSTRACT FROM AUTHOR]

Multichannel digital sinewave generators play a key role in digital automated impedance bridges. Along with the technological progress in the development of commercial data acquisition (DAQ) boards, which brings with it improvements in their metrological and functional properties, it is possible to realize the DAQ-based high-precision multichannel generators. This paper describes the evaluation of properties of three commercial DAQs, available in the form of PCI eXtensions for Instrumentation modules and working as two-channel generators supervised by software developed by the authors. Due to the fact that the main application area of these generators is digital impedance bridges, this paper presents research results the most relevant for the impedance bridges, i.e., the stability of amplitude ratio and phase difference as well as total harmonic distortion and spurious-free dynamic range. The results and conclusion presented in this paper may be useful when choosing DAQs intended to be used in the multichannel generators. [ABSTRACT FROM AUTHOR]

This paper is an extension of the procedure pointed out to evaluate the distortion of the exponential signal, modeled as multiexponential signal with different amplitudes and time constants. This procedure evaluates the distortion by applying the Prony-like method to the signal reconstructed by zero-crossing time evaluated on the difference between the exponential original signal and the reference sinusoidal one. The extension proposed in this paper concerns with the use of the low-chirp signal as reference instead of the sinusoidal signal. The low-chirp signal permits to increase the number of the zero-crossing time in the section of exponential signal with the higher slope and decreasing in the section with the lower slope. This setting permits to estimate the distortion of the exponential signal with higher accuracy and precision. The parameters’ amplitude, phase, and start frequency of the reference low-chirp signal are used to reconstruct the exponential signal in the zero-crossing time in order to overcome the problem of the high-resolution sampling. Their estimation is carried out by the time-varying sine-fitting algorithm that processes the resulting signal that is the difference between the exponential original signal and the low-chirp signal. Advantages of the proposed extended procedure regard the direct estimation of the reference low-chirp signal parameters from the resulting signal over-sampled at low resolution, and the use of only one input acquisition channel that permits to overcome the synchronization problem between the reference and the resulting signal. The numerical and experimental tests validate the extended procedure. [ABSTRACT FROM AUTHOR]

In this paper, we proposed to evaluate the optimal phasor measurement unit (PMU) placement based on the sum of variance (SV) of the robust estimators. Variance is traditionally used as a measure of the quality of estimates. In this paper, after satisfying the requirements of the minimum number of PMUs, maximum measurement redundancy, and observability, the placements obtained are further distinguished on the basis of the variance of the estimated states. Both the weighted least squares (WLS) and robust estimators are considered. Examples on the IEEE 30-bus system using least absolute value (LAV) estimation are given. The covariance of the state estimates from the WLS can be calculated using the existing formulas. However, there is no equivalent formula for the robust LAV estimator. A formula is derived in this paper using influence function to approximately calculate the covariance matrix of the state estimates from the robust LAV estimator. The optimum placement, i.e., the placement with the smallest SV, can be selected. [ABSTRACT FROM AUTHOR]

Nowadays, an increasing concern about people and environmental health and safety is spreading all over the world, and technologies such as efficient monitoring systems are furthered. In the field of air quality, filtering systems, especially based on activated carbons (ACs), are commonly used. In most cases, their state of health is not monitored, and their time of life is based on statistical and a priori evaluations. This paper proposes a novel microsensor platform for the real-time monitoring of AC filters based on the impedance measurements during gas exposition. A metrological characterization of the novel proposed instrument is provided in this paper, by comparing its output to a reference $RLC$ meter. A calibration and adjustment procedure is developed in order to analyze the device measurement capabilities and obtain correction coefficients. Experiments with different gas typologies are presented, and the analysis of filters impedance dynamics is provided. [ABSTRACT FROM AUTHOR]

The diagnostic machinery monitoring system presented in this paper coordinates the acquisition of vibration and speed estimates for an electric machine. It functions even when the machine is “off” or spinning down. This effectively turns the machine into its own mechanical network analyzer. Data from this system can be used to correlate electrical and mechanical data in order to distinguish a variety of pathologies in the machine and its mechanical mounts. The entire sensor system powers itself from surrounding magnetic fields, requiring no ohmic contact or special power wiring. The system presented in this paper presents a unique approach for fusing data from multiple sensors to create a coordinated picture of machine operation on a self-powered platform. [ABSTRACT FROM AUTHOR]

Electrical capacitance tomography exhibits great potentials in the visualization measurement of industrial processes, and high-precision images are of great significance for the reliability and usefulness of measurement results. In this paper, we propose a deep learning-based inversion method to ameliorate the reconstruction accuracy. With the aid of the deep learning methodology, the prior from the images reconstructed by a certain imaging technique to the true images is abstracted and stored in the deep extreme learning machine. A new cost function is constructed to encapsulate the prior from the proposed deep learning model and the domain expertise about imaging targets, and the split Bregman algorithm and the fast iterative shrinkage thresholding technique are combined into a new numerical method to effectively solve it to get the final reconstruction. The numerical and experimental results validate that the inversion method proposed in this paper reduces the reconstruction artifacts and deformations and leads to the much improvement in the imaging quality. [ABSTRACT FROM AUTHOR]

The Conference on Precision Electromagnetic Measurements (CPEM) 2014 was held at Windsor Barra Hotel in Rio de Janeiro, Brazil, from August 24 to August 29, 2014 (http://www.inmetro.gov.br/cpem2014). Experts working in the field of precision metrology and its applications to real-world situations gathered to present and discuss recent advances and open issues/questions. [ABSTRACT FROM PUBLISHER]

The Sensors Applications Symposium (SAS) 2020 was the 15th edition of the flagship professional event in the sensor technology and application area organized by the IEEE Instrumentation and Measurement Society (IMS). It brought together sensor developers, innovators, and users, providing a forum for the exploration of new ideas, developments, implementations, and applications in the field. SAS 2020 was scheduled to take place on March 9–11, 2020, in Kuala Lumpur, Malaysia. However, the outbreak of the Covid-19 lead to the sudden and necessary decision of converting the event to a virtual conference. Indeed, IEEE SAS 2020 was arguably the first IMS and one of the first IEEE conferences that took place in that way, thus acting as a model for subsequent events. Nonetheless, the 2020 edition of the IEEE SAS has drawn significant professional interest worldwide leading to receiving 96 submissions of which 73 were accepted for the presentation at the virtual event. The review process of the symposium was designed to ensure the high quality of accepted papers authored by specialists from all over the world. Accepted papers were divided for presentation into ten virtual Oral Sessions and one large virtual Poster Session available for online access by the attendees during the three weeks of the virtual event. [ABSTRACT FROM AUTHOR]

In this paper, the effects of motion blur on 2-D digital image correlation (DIC) measurements are discussed, with a particular focus on the description of displacement measurement uncertainty. The research started with the simulation of motion blur with a suitable literature-based algorithm. Then the state of the art of uncertainty analysis in the context of DIC was compared with simulation results, and it was found that the effects of motion blur on uncertainty are not predicted correctly by the literature models. This phenomenon is explained by the fact that the literature models do not consider motion blur. Consequently, a simple monodimensional case is analyzed. In this way, it has been possible to evaluate the sensitivity of DIC correlation function [evaluated as the sum of squared differences (SSD)] to motion blur. Using these results, it is possible to extend the analysis to the case of a generic image with the help of a power-law model. Eventually, the model proposed in this paper is able to represent the effects of motion blur correctly. [ABSTRACT FROM AUTHOR]

This paper reviews and analyzes studies concerning measurement uncertainty, examining 114 papers published between 2004 and 2010 in the following international journals: IEEE Transactions on Instrumentation and Measurement, Measurement, Flow Measurement and Instrumentation, and Precision Engineering. The papers were classified according to six different approaches identified during the research and six different methods of calculating uncertainty used by the authors of the researched articles. This paper provides a short summary of the state of the art of measurement uncertainty, analyzes the research scenario on the theme, and, finally, brings suggestions on future work based on the analysis. [ABSTRACT FROM AUTHOR]

Presents a study on a developed measurement system allowing researchers to measure the velocity of different two-dimensional (2-D) objects. What the measurement system was tested for; Contents of the measurement system; Presentation of different measurements at a test stand and at an industrial paper machine to demonstrate the accuracy of the measurement system and its flexibility and robustness.

Presents information on the technical papers presented during the Conference on Precision Electromagnetic Measurements held in Sydney, Australia in May 2000. Editors who worked on the compilation of the papers; Evaluation of the papers presented; Reviewers of the technical papers.

As one of the most important and essential elements of machines, rolling element bearings always fail due to the severe operating environment. Bearing failures usually result in the periodic impulses, which are the most crucial feature for the bearing diagnosis. These impulses may be overwhelmed by the background noises or other unrelated components. Many traditional features in the time domain such as kurtosis and root mean square (rms) are invalid in some cases. They are ineffective in detecting periodic impulses. This paper proposed a novel frequency-domain index, named envelope spectrum (ES) L-kurtosis (ESLK), to detect the periodicity of impulses. In this paper, simulations and bearing degradation data are utilized to clarify the properties of ESLK. In addition, this paper also proposed an ESLK-based method to locate the frequency range of periodic impulses. This method is verified by simulations and an experiment. The results illustrate that the proposed method performs better than the traditional kurtosis-based method. [ABSTRACT FROM AUTHOR]

Artificial intelligence evolved as a powerful tool in condition monitoring of the induction motor for early diagnosis of bearing faults. This paper attempted to identify the features to improve the accuracy of diagnosis using the benchmark database of the Case Western Reserve University (CWRU) and the Machinery Fault Prevention Technology (MFPT). In this paper, 18 time-domain features are extracted constituting six proposed time-dependent spectral features (TDSFs) and 12 statistical time-domain features. For the first time, a set of six TDSFs are extracted to diagnose the bearing faults. This involves extracting frequency-domain features using the relationship between Parseval’s theorem and the Fourier transform directly from the time domain. Particle swarm optimization (PSO) and wheel-based differential evolution (WBDE) feature selection algorithms are also implemented to identify four prominent features. It is found that three of the four selected features are TDSF features, and results of selected features revealed the attainment of 90.92% for 48 class identifications of CWRU database and 100% for 17 class identifications of the MFPT database, respectively. [ABSTRACT FROM AUTHOR]

This paper is a nontrivial extension of prior work on rate and position table leveling and inertial and magnetic sensors calibration techniques. The table leveling is essential for a class of calibration techniques using known stimuli, herein referred to as classical techniques. Such techniques are effective for the calibration of inertial sensors as they usually lead to closed-form solutions and body frame calibrations. However, the classical techniques are negatively affected by table leveling and azimuth orientation errors or by changes in the direction of the reference field. These errors are collectively referred to as field alignment errors in this paper. The impact of field alignment errors is usually avoided by using reference-free calibrations which rely on satisfying the invariance of the field modulus constraint. This constraint works well for orthogonal sensor triads as it leads to unique solutions. There is a great body of work dedicated to studying such calibration techniques for orthogonal sensor triads. However, redundant sensor configurations have too many degrees of freedom to satisfy the invariance of the modulus constraint; therefore, require special techniques. This paper introduces a novel approach that can be used to produce body frame calibrations for skew redundant sensor configurations in the presence of field alignment errors. Unlike prior work, no simplifying assumptions are made on the redundant sensor configuration (e.g., multiple orthogonal triads). The new method is showcased for the dodecahedron configuration, one of the most complex skew redundant configurations. [ABSTRACT FROM AUTHOR]

Translational position error in microwave and millimeter-wave synthetic aperture radar (SAR) imaging systems can cause significant image quality degradation, particularly in nondestructive testing and evaluation (NDT&E) applications where the distance to the imaging object is relatively short. In this paper, this translational position error problem is fully studied through electromagnetic simulation. The results show that among possible geometrical causes of error, a translational position error, in the height direction, is the dominant factor in image quality degradation. Subsequently, a corresponding height position error compensation method is proposed and analyzed. The extensive simulations and measurement are performed in the X-band (8.2–12.4 GHz) frequency range. Then, by defining several evaluation metrics, the relationship between image quality and height position error is discussed quantitatively. The measured results show good agreement with the simulated results, which validates the effectiveness of the proposed analysis approach and the compensation method. The methodology proposed in this paper can be used to evaluate the feasibility or help define the required specifications of a microwave SAR imaging system for a specific application. [ABSTRACT FROM AUTHOR]