| 1. |
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| 2. |
- Baumann, N., et al.
(författare)
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Piepser 2.0 : A Self-Sustaining Smartwatch to Maximize the Paragliders Flytime
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:4, s. 1445-1454
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Tidskriftsartikel (refereegranskat)abstract
- The main motivation of paraglider pilots is to stay in the air for as long as possible. Therefore, paraglider pilots are always searching for thermal upwind that allow them to gain altitude. These thermal lifts are difficult to detect. Therefore, sensors and devices that indicate the vertical speed (so-called variometers) are widely used among paraglider pilots. This article presents the design and the implementation of an ultralow-power, self-sustaining, high-precision, wrist-worn variometer with a minimal form factor but infinite lifetime, which can visually and acoustically indicate the vertical velocity. This article demonstrates the benefits of combining multisource energy harvesting (EH) for wearable devices with low power design, exploiting a novel near-threshold ARM Cortex-M4F microcontroller, the Ambiq Apollo2, for the onboard processing. The experimental results show a power consumption of only 17.12~\mu \text{W} in sleep mode and 1937.21~\mu \text{W} in the worst case scenario when processing the data and outputting an audio feedback. Measurements confirmed that combining both thermal and solar EH makes the designed electronics self-sustaining. Without EH, the system will be operational for up to 372 h in always-on mode (worst case scenario) supplied by a 200-mAh lithium-ion battery. © 1963-2012 IEEE.
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| 3. |
- Beltramelli, Luca, et al.
(författare)
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Energy efficiency of slotted LoRaWANcommunication with out-of-band synchronization
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662.
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Tidskriftsartikel (refereegranskat)abstract
- Although the idea of using wireless links for covering large areas is not new, the advent of Low Power Wide area networks (LPWANs) has recently started changing the game. Simple, robust, narrowband modulation schemes permit the implementation of low-cost radio devices offering high receiver sensitivity, thus improving the overall link budget. The several technologies belonging to the LPWAN family, including the well-known LoRaWAN solution, provide a cost-effective answer to many Internet-of-things (IoT) applications, requiring wireless communication capable of supporting large networks of many devices (e.g., smart metering). Generally, the adopted medium access control (MAC) strategy is based on pure ALOHA, which, among other things, allows to minimize the traffic overhead under constrained duty cycle limitations of the unlicensed bands. Unfortunately, ALOHA suffers from poor scalability, rapidly collapsing in dense networks. This work investigates the design of an improved LoRaWAN MAC scheme based on slotted ALOHA. In particular, the required time dissemination is provided by out-of-band communications leveraging on Radio Data System(FM-RDS) broadcasting, which natively covers wide areas both indoor and outdoor. An experimental setup based on low-cost hardware is used to characterize the obtainable synchronization performance and derive a timing error model. Consequently, improvements in success probability and energy efficiency have been validated by means of simulations in very large networks with up to 10000 nodes. It is shown that the advantage of the proposed scheme over conventional LoRaWAN communication is up to 100% when short update time and large payload are required. Similar results are obtained regarding the energy efficiency improvement, that is close to 100% for relatively short transmission intervals and long message duration; however, due to the additional overhead for listening the time dissemination messages, efficiency gain can be negative for very short duration of message fastly repeating.
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| 4. |
- Capriglione, D., et al.
(författare)
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Experimental Analysis of Filtering Algorithms for IMU-Based Applications under Vibrations
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- The use of microelectro-mechanical systems (MEMS)-based inertial measurement units (IMUs) is widespread in many applications concerning monitoring, diagnostic, and/or controlling in navigation and transportation systems, as well as in low-cost applications for automotive and aeronautical fields. The data provided by the set of sensors typically present in IMUs, as accelerometers, gyroscopes, and magnetometers, are often used also for feeding suitable filtering and positioning algorithms able to correct the attitude and path of the vehicle on which they are installed or to provide the analytical redundancy needed for online diagnosis. Nevertheless, on one hand, the performance of low-cost MEMS-based IMUs is certified only under a small set of nominal operating conditions, and on the other hand, the filtering algorithms are often designed and verified under canonical additive noises. In this framework, this article proposes a test plan and a test setup for analyzing and characterizing the performance of filtering algorithms for positioning based on data coming from low-cost IMUs and able to verify systematically the operation of such algorithms under real scenarios. Two kinds of very popular filtering algorithms have been considered, namely, the complementary filter and the attitude and heading reference systems (AHRS) Kalman filter, which belong to two opposite approaches. The experimental results prove how the typical vibrations present in real scenarios can significantly affect the performance of such algorithms. © 1963-2012 IEEE.
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| 5. |
- Capriglione, D., et al.
(författare)
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Soft Sensors for Instrument Fault Accommodation in Semiactive Motorcycle Suspension Systems
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:5, s. 2367-2376
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Tidskriftsartikel (refereegranskat)abstract
- This article describes the development and experimental verification of an instrument fault accommodation (IFA) scheme for front and rear suspension stroke sensors in motorcycles equipped with electronically controlled semiactive suspension systems. In particular, the IFA scheme is based on the use of nonlinear autoregressive with exogenous inputs (NARX) neural networks (NNs) employed as soft sensors for feeding the suspension control strategy back with measurement even in the presence of faults occurred on the sensors. Different NN architectures have been trained and tuned by considering real data acquired during several measurement campaigns. The performance has been compared with that of the well-known half-car model (HCM). Very satisfying results allow the soft sensor to be really integrated into fault-tolerant control systems. In experimental road tests, an implementation of the proposed IFA scheme on a low-cost microcontroller for automotive applications showed to be in real time. In this article, these experimental results are shown to prove the good performance of the IFA scheme in different motorcycle operating conditions. © 1963-2012 IEEE.
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| 6. |
- Catelani, Marcantonio, et al.
(författare)
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Optimizing Maintenance Policies for a Yaw System Using Reliability-Centered Maintenance and Data-Driven Condition Monitoring
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 69:9, s. 6241-6249
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Tidskriftsartikel (refereegranskat)abstract
- System downtime and unplanned outages massively affect plant productivity; therefore, the reliability, availability, maintainability, and safety (RAMS) disciplines, together with fault diagnosis and condition monitoring (CM), are mandatory in energy applications. This article focuses on the optimization of a maintenance plan for the yaw system used in an onshore wind turbine (WT). A complete reliability-centered maintenance (RCM) procedure is applied to the system to identify which maintenance action is the optimal solution in terms of cost, safety, and availability. The scope of the research is to propose a new customized decision-making diagram inside the RCM assessment to reduce the subjectivity of the procedure proposed in the standard and save the cost by optimizing maintenance decisions, making the projects more cost-efficient and cost-effective. This article concludes by proposing a new diagnostic method based on a data-driven CM system to efficiently monitor the health and detect damages in the WT by means of measurements of critical parameters of the tested system. This article highlights how a reliability analysis, during the early phase of the design, is a very helpful and powerful means to guide the maintenance decision and the data-driven CM.
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| 7. |
- Chang, Lin, et al.
(författare)
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Multisurface Interferometric Algorithm and Error Analysis With Adaptive Phase Shift Matching
- 2022
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9456 .- 1557-9662. ; 71
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Tidskriftsartikel (refereegranskat)abstract
- To simultaneously measure topographies of both surfaces of a transparent plate through wavelength-tuning interferometry at arbitrary cavity lengths, a flexible phase shift matching algorithm (FPSMA) is proposed. The FPSMA includes two parts: 1) taking the four-term third-order Nuttall window as an example, a phase demodulation approach is designed and analyzed for extracting the harmonic phases of the front surface, rear surface, and thickness variation of the measured plate and 2) based on the residual error analysis of the developed 5N-Nuttall algorithm for different cavity length coefficients M and the phase-shifting parameters N , a parameter-change technique that allows the developed phase demodulation approach is applied to arbitrary cavity lengths by adaptively changing the phase shifts and frames of the captured interferograms. By this technique, the algorithm failures due to the spectral aliasing of harmonics can be avoided effectively and conveniently, and then the correct phase demodulation can be ensured. Besides, using the developed method, when the values of N or M are chosen in advance, the corresponding available measurement ranges can be given. Besides, the relationship between the window length and the measurement limitation of the measurable thinnest optical thickness is investigated. Considering the common linear and nonlinear errors in the wavelength-shifting process, the error analysis of FPSMA is performed and discussed for situations close to reality. The comparative studies and the experimental results of two transparent parallel plates also support the performance of the developed FPSMA.
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| 8. |
- Cheng, Liu, et al.
(författare)
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EEG-CLNet : Collaborative Learning for Simultaneous Measurement of Sleep Stages and OSA Events Based on Single EEG Signal
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 72
-
Tidskriftsartikel (refereegranskat)abstract
- Sleep-stage and apnea-hypopnea index (AHI) are the most important metrics in the diagnosis of sleep syndrome disease. In previous studies, these two tasks are usually implemented separately, which is both time- and resource-consuming. In this work, we propose a novel single electroencephalogram (EEG)-based collaborative learning network (EEG-CLNet) for simultaneous sleep staging and obstructive sleep apnea (OSA) event detection through multitask collaborative learning. The EEG-CLNet regards different tasks as a common unit to extract features from intragroups via both local parameter sharing and cross-task knowledge distillation (CTKD), rather than just sharing parameters or shortening the distance between different tasks. Our approach has been validated on two datasets with the same or better performance than other methods. The experimental results show that our method achieves a performance gain of 1%-5% compared with the baseline. Compared to previous works where two or even more models were required to perform sleep staging and OSA event detection, the EEG-CLNet could reduce the total number of model parameters and facilitate the model to mine the hidden relationships between different task semantic information. More importantly, it effectively alleviates the task bias problem in hard parameter sharing. As a consequence, this approach has notable potential to be a solution for a lightweight wearable sleep monitoring system in the future.
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| 9. |
- Di Caro, D., et al.
(författare)
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Quality Assessment of the Inshell Hazelnuts Based on TD-NMR Analysis
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:6, s. 3770-3779
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Tidskriftsartikel (refereegranskat)abstract
- Nondestructive testing is critical in the quality detection of products. Among several techniques, time-domain nuclear magnetic resonance (TD-NMR) is gaining attention in the field of food quality control, thanks to its ability to detect liquid and solid materials, which are strictly related to the quality of some kinds of products. In this article, a novel method for the inline quality evaluation of the inshell hazelnuts, based on TD-NMR analysis, is disclosed. Different studies have been carried out on the quality control of hazelnuts or, more in general, shell fruit. They usually focus on laboratory application and the analysis of a single physical property. Conversely, the proposed method focuses on the signal processing with the aim of reducing the execution time making the procedure suitable for an inline application. Moreover, the main hidden defects are analyzed together to identify the defective nuts from the good ones in a two-class classification procedure. © 1963-2012 IEEE.
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| 10. |
- Fedorov, Igor, et al.
(författare)
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A two-layer 3D reconstruction method and calibration for multi-camera-based volumetric positioning and characterization
- 2021
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- A three-dimensional (3D) reconstruction method and multi-camera calibration using multiple artificial reference markers have been used for precise volumetric surveillance of fast-flying objects. The method uses a two-layer 3D reconstruction that integrates two multi-camera stereo-nodes. The fields of view of stereo nodes are directed at an acute angles to each other to provide greater coverage with the given constraints and to determine the flight characteristics of objects in 3D. The object’s flight reconstruction includes a “rough” estimation of its positions relative to selected artificial reference points in both stereo nodes separately and subsequent “refinement” of calculated positions. In this paper, we describe the proposed method and calibration technique, using a multi-camera system to measure object characteristics in 3D. The proposed method applies to volumetric surveillance in situations where it is necessary to count, track, and analyze the activities of flying objects, especially birds, using high spatial resolution.
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| 11. |
- Ferrari, P., et al.
(författare)
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Resilient time synchronization opportunistically exploiting UWB RTLS infrastructure
- 2022
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 71, s. 1-10
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Tidskriftsartikel (refereegranskat)abstract
- Ultra Wide Band (UWB) based solutions for real time localization are starting to be widely diffused. They use two-way ranging scheme achieving indoor positioning accuracy well below ten centimeters. These wireless devices are based on counters with picosecond resolution, which could be used also for nodes time synchronization. This work aims to propose an opportunistic approach for transparently obtaining multiple accurate time synchronization from low-cost infrastructure of Real Time Location Systems (RTLS). After the description of the proposed approach, the idea is demonstrated using off-the-shelf Ultra Wide Band (UWB) modules from Decawave and their related software. Thanks to hardware timestamping support inside the core architecture, the realized wireless station is able to simultaneously lock and track several time references generated by the UWB module. The extensive experimental characterization evaluates both the uncertainty of the reference signal generated by the UWB receiver, and the time synchronization uncertainty of the whole host system running a Proportional Integrative (PI) control loop for locking the master reference clock. The time reference pulses are delivered by the UWB modules with a maximum jitter on the order of 40 ns, whereas the synchronization uncertainty is less than 10 ns. IEEE
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| 12. |
- Gao, Yiping, et al.
(författare)
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A Multilevel Information Fusion-Based Deep Learning Method for Vision-Based Defect Recognition
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 69:7, s. 3980-3991
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Tidskriftsartikel (refereegranskat)abstract
- Vision-based defect recognition is an important technology to guarantee quality in modern manufacturing systems. Deep learning (DL) becomes a research hotspot in vision-based defect recognition due to outstanding performances. However, most of the DL methods require a large sample to learn the defect information. While in some real-world cases, it is difficult and costly for data collecting, and only a small sample is available. Generally, a small sample contains less information, which may mislead the DL models so that they cannot work as expected. Therefore, this requirement impedes the wide applications of DL in vision-based defect recognition. To overcome this problem, this article proposes a multilevel information fusion-based DL method for vision-based defect recognition. In the proposed method, a three-level Gaussian pyramid is introduced to generate multilevel information of the defect so that more information is available for model training. After the Gaussian pyramid, three VGG16 networks are built to learn the information and the outputs are fused for the final recognition result. The experimental results show that the proposed method can extract more useful information and achieve better performances on small-sample tasks, compared with the conventional DL methods and defect recognition methods. Furthermore, the analysis results of the robustness and response time also indicate that the proposed method is robust for the noise input, and it is fast for defect recognition, which takes 13.74 ms to handle a defect image.
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| 13. |
- Ge, Chenjie, 1991, et al.
(författare)
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Deep Feature Clustering for Seeking Patterns in Daily Harmonic Variations
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- This article proposes a novel scheme for analyzing power system measurement data. The main question that we seek answers in this study is on “whether one can find some important patterns that are hidden in the large data of power system measurements such as variational data.” The proposed scheme uses an unsupervised deep feature learning approach by first employing a deep autoencoder (DAE) followed by feature clustering. An analysis is performed by examining the patterns of clusters and reconstructing the representative data sequence for the clustering centers. The scheme is illustrated by applying it to the daily variations of harmonic voltage distortion in a low-voltage network. The main contributions of the article include: 1) providing a new unsupervised deep feature learning approach for seeking possible underlying patterns of power system variation measurements and 2) proposing an effective empirical analysis approach for understanding the measurements through examining the underlying feature clusters and the associated reconstructed data by DAE.
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| 14. |
- Ghorai, Sagar, et al.
(författare)
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A setup for direct measurement of the adiabatic temperature change in magnetocaloric materials
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 72, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- In order to find a highly efficient, environmentally-friendly magnetic refrigerant, direct measurements of the adiabatic temperature change ΔTadb are required. Here, in this work, a simple setup for the ΔTadb measurement is presented. Using a permanent magnet Halbach array with a maximum magnetic field of 1.8 T and a rate of magnetic field change of 5 T/s, accurate determination of ΔTadb is possible in this system. The operating temperature range of the system is from 100 to 400 K, designed for the characterization of materials with potential for room temperature magnetic refrigeration applications. Using the setup, ΔTadb of a first-order and two second-order compounds have been studied. Results from the direct measurement for the first-order compound have been compared with ΔTadb calculated from the temperature and magnetic field-dependent specific heat data. By comparing results from direct and indirect measurements, it is concluded that for a reliable characterization of the magnetocaloric effect (MCE), direct measurement of ΔTadb should be adopted.
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| 15. |
- Hua, D., et al.
(författare)
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A Novel Ferrofluid Rolling Robot : Design, Manufacturing, and Experimental Analysis
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- With the increasing applications of magnetic robots in medical instruments, the research on different structures and locomotion approaches of magnetic robots has become a hotspot in recent years. A ferrofluid rolling robot (FRR) with magnetic actuation is proposed and enabled to realize a novel locomotion approach in this article. The drive performance of ferrofluid is elaborated, which is characterized by the magnetic torque of a rectangle-shaped object filled with ferrofluid under magnetic field. First, the proposed structure and locomotion mechanism of the FRR are detailed. Moreover, based on the established mathematical models of the FRR, the simulations with straight and turning locomotion are carried out, respectively. Finally, the FRR prototype is manufactured by 3-D printing, and experimental results demonstrate that the feasibility of straight and turning locomotion is verified. The locomotion performance of the FRR is in good agreement with the theoretical models where the root mean square (rms) value of displacement for experiments and simulations is 1.2 mm. In this work, the proposed FRR can automatically switch from straight to turning locomotion with a fast response in an external magnetic field, and does not has magnetism when without a magnetic field.
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| 16. |
- Kampik, Marian, et al.
(författare)
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Comparison of a Thermal AC Voltage Standard in the 1 MHz to 30 MHz Frequency Range
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- The paper presents results of a comparison of a travelling AC voltage standard, which was a fused-silica NIST planar multijunction thin-film thermal converter (PMJTC). The AC-DC voltage transfer difference of the standard was measured at 2 V and selected frequencies from 1 MHz to 30 MHz against primary thermal AC voltage standards at SUT, INRiM, RISE and Trescal.
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| 17. |
- Kasebzadeh, Parinaz, 1985-, et al.
(författare)
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Joint Pedestrian Motion State and Device Pose Classification
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 69:8, s. 5862-5874
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Tidskriftsartikel (refereegranskat)abstract
- Novel features for joint classification of gait and device modes are proposed and multiple machine learning methods are adopted to jointly classify the modes. The classification accuracy as well as the F1 score of two standard classification algorithms, K-nearest neighbor (KNN) and Gaussian process (GP), are evaluated and compared against a proposed neural network (NN)-based classifier. The proposed features are the correlation scores of a detected gait cycle relative to a set of unique gait signatures as well as the gait cycle time, all extracted from handheld inertial measurement units (IMUs). Each gait signature is defined such that it contains one full cycle of the human gait. In order to take the temporal correlation between classes into account, the initial classifiers’ estimates are fed into a hidden Markov model (HMM) unit to obtain the final class estimates. The performance of the proposed method is evaluated on a large data set, including two classes of gait modes (walking and running) and four classes of device modes (fixed and face-up in the hand, swinging in the hand, in the pocket, and in the backpack). The experimental results validate the reliability of the considered features and effectiveness of the HMM unit. The initial classification accuracy of the NN-based approach is 91%, which is further improved to 99% after the smoothing stage on the validation set and 98% on the test set.
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| 18. |
- Kluss, Joni, et al.
(författare)
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High-Frequency Current Transformer Design and Implementation Considerations for Wideband Partial Discharge Applications
- 2021
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- High-frequency current transformers are popular noninvasive inductive wideband sensors. Despite simplicity in design and operational principle, implementation of such sensors for partial discharge applications requires careful consideration, particularly in the higher frequency range where traveling wave attenuation and distortion is relevant. First, the role of design variables, including core materials, winding design, and shielding practices on sensor sensitivity and frequency characteristics (transfer impedance) are presented. Next, the suitability of the constructed sensors for partial discharge applications is assessed. The designed wideband sensors are suitable for laboratory applications with standard measurement circuits and controlled conditions. The low-level magnitude and frequency spectrum of the discharge pulses hinders signal integrity in relation to the placement of the sensors within the measurement circuit, signal amplification, and pulse repetition rate (pulse resolution). To enable most stringent detection levels under 1 pC, efforts are needed in distortionless amplifier design and interference mitigation.
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| 19. |
- Li, Xinmin, et al.
(författare)
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A Pin-on-Disk Study of the Tribological Properties of Polyoxymethylene (POM) Gear Materials
- 2024
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 73
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Tidskriftsartikel (refereegranskat)abstract
- Polyoxymethylene (POM) is now widely used as a gear material due to its excellent mechanical properties. There have been several studies on the tribology of POM; however, most of them focused solely on the material itself without integrating practical applications. This study investigates the tribological properties of POM-POM combinations in conjunction with the application of POM gears. Using a pin-on-disk machine, we simulate the sliding part of gear meshing. The influences of contact pressures (40 and 50 MPa), sliding speed (0.1 and 0.5 m/s), and lubrication on the tribological performance of POM pin sliding against POM disk were studied. The results showed that grease can reduce adhesion between sliding surfaces and effectively improve the tribological performance of the POM-POM combination. The friction coefficient decreases with increasing contact pressure, which is consistent with the existing models of the frictional behavior of polymer-polymer systems. The wear coefficient exhibits contrasting relationships with increasing contact pressure at high and low velocities. Because the wear mechanism changes from predominantly abrasion at low velocity to adhesion-peeling off at high velocity. Both the friction and wear coefficients decrease with increasing sliding velocity. The specific mechanisms of the influence of different lubrication conditions, pressures, velocities, and PV values on friction and wear are described and discussed throughout this article.
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| 20. |
- Liu, Xing, et al.
(författare)
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Constrained Wrapped Least Squares: A Tool for High Accuracy GNSS Attitude Determination
- 2022
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 1557-9662 .- 0018-9456. ; 71
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Tidskriftsartikel (refereegranskat)abstract
- Attitude determination is a popular application of Global Navigation Satellite Systems (GNSS). Many methods have been developed to solve the attitude determination problem with different performance offerings. We develop a constrained wrapped least-squares (C-WLS) method for highaccuracy attitude determination. This approach is built on an optimization model that leverages prior information related to the antenna array and the integer nature of the carrier-phase ambiguities in an innovative way. The proposed approach adopts an efficient search strategy to estimate the vehicle’s attitude parameters using ambiguous carrier-phase observations directly, without requiring prior carrier-phase ambiguity fixing. The performance of the proposed method is evaluated via simulations and experimentally utilizing data collected using multiple GNSS receivers. The simulation and experimental results demonstrate excellent performance, with the proposed method outperforming the ambiguity function method, the constrained LAMBDA and multivariate constrained LAMBDA methods, three prominent attitude determination algorithms.
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| 21. |
- Ma, Xinyu, et al.
(författare)
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Power Estimation for Indoor Light Energy Harvesting Systems
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 0018-9456 .- 1557-9662. ; 69:10, s. 7513-7521
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Tidskriftsartikel (refereegranskat)abstract
- The growing interest in indoor light energy harvesting for wireless sensor systems and low-power electronics has created a demand for systematic design methods that optimize the system implementation and component choices for different lighting scenarios. Although the spectrum of light is known to influence the efficiency and output power of a photovoltaic cell, existing power estimation methods neglect the spectrum. By contrast, the power estimation method proposed in this paper takes spectral and intensity information into account. It uses low-cost sensors to measure spectral information and select an appropriate device model based on the classification of the light source. The method is evaluated under different light conditions, including individual light sources, mixed artificial light sources, and mixtures of artificial light and sunlight. The results demonstrate that the proposed implementation selects a reasonable model in most cases, including mixed light source conditions. Using light source specific models for photovoltaic panels, the resulting estimation error is low and has clear advantages over methods neglecting spectral information.
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| 22. |
- Mayer, P., et al.
(författare)
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RTK-LoRa : High-Precision, Long-Range, and Energy-Efficient Localization for Mobile IoT Devices
- 2021
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- High-precision global navigation satellite system (GNSS) is a crucial geolocalization feature enabling a wide range of applications, from mobile Internet-of-Things devices to autonomous drones and self-driving vehicles. Real-time kinematic (RTK) is a GNSS technology that attracting increased interest due to the centimeter precision achievable when wireless communication is present on the devices. On the other hand, sending continuously wireless data increases the energy consumption and the cost of the solution, especially when communication is carried over the 4G network. Due to those drawbacks, RTK is not much exploited in the localization of battery-operated devices. This work combines RTK with low-power long-range communication to achieve submeter precision in an energy-efficient RTK-based system. The proposed system exploits a state-of-the-art RTK-GNSS module combined with a long range (LoRa) to achieve geolocalization with minimal wireless radio infrastructure requirements. An energy-efficient algorithm is proposed and implemented in a microcontroller to have a quick startup and high accuracy. We evaluate three different GNSS modules and compare their performance in terms of power and accuracy. Experimental results, with in-field measurements, show that an average geolocalization precision of tens of centimeters is achievable on a battery-operated wireless end node connected to a single base station used as a geostationary reference anchor placed at kilometers of distance. The peak precision measured is below 10 cm. © 1963-2012 IEEE.
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| 23. |
- Ottosson, Patrik, et al.
(författare)
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An ultra-wideband system for measuring the dielectric properties of mineral compounds in a heat-reaction chamber at high temperatures
- 2023
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 72
-
Tidskriftsartikel (refereegranskat)abstract
- A measurement system for the measurement of microwave dielectric properties of mineral compounds at temperatures up to +1000°C is presented. It includes the simultaneous measurement of mass and temperature. Samples volumes in the range 0.01 to 0.1 m 3 can be studied. The system comprises a heat reaction chamber on a mass scale with mounted ultra-wideband (UWB) radio sensors and temperature probes. The complex refractive index is determined from the UWB signals using a technique with windowing to suppress interference and fitting of a modelled signal to the experimental ones. The developed method is validated by measuring the complex refractive index of water from +82°C down to +23°C and comparing with literature values. The systems is used to study calcination of limestone, i.e. the chemical decomposition of CaCO 3 to CaO and CO 2 when heated up to +1000°C. The chemical decomposition is clearly seen as a decrease in mass and as significant changes in the complex refractive index. The system could be used also for other mineral compounds and other types of materials.
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| 24. |
- Peng, Changqing, et al.
(författare)
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LightFlow : Lightweight unsupervised defect detection based on 2D Flow
- 2024
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662.
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Tidskriftsartikel (refereegranskat)abstract
- In the industrial production process, unsupervised visual inspection methods have obvious advantages over supervised visual inspection methods due to the scarcity of defect samples, annotation costs and the uncertainty of defect generation. Currently, unsupervised defect detection and localization methods have demonstrated significant improvements in detection accuracy to find numerous applications in industrial inspection. Nonetheless, the complexity of these methods limits their practical application. In this paper, we integrate the FastFlow model plugin as a probability distribution by introducing a simpler and lightweight CNN pre-trained backbone. Concurrently, various training strategies are employed to optimize the 2D Flow module within the Lightweight unsupervised flow model (LightFlow). Notably, the number of model parameters in the LightFlow model is only 1/4 of the original model size of the typical Vision Transformer (ViT) model CaiT. Thereby, this offers heightened training efficiency and speed. Therefore, extensive experimental results on three challenging anomaly detection datasets (MVTec AD, VisA, and BTAD) using various CNN backbones and multiple current state-of-the-art vision algorithms demonstrate the effectiveness of our approach. Specifically, the existing method can achieve 99.1% and 95.2% image-level AUROC (area under the receiver operating characteristic) in MVTec AD and VisA, respectively. IEEE
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| 25. |
- Peng, Xiangdong, et al.
(författare)
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DSCSSA: A Classification Framework for Spatiotemporal Features Extraction of Arrhythmia Based on the Seq2Seq Model With Attention Mechanism
- 2022
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 71
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Tidskriftsartikel (refereegranskat)abstract
- In the field of arrhythmia classification, classification accuracy has always been a research hotspot. However, the noises of electrocardiogram (ECG) signals, the class imbalance of ECG data, and the complexity of spatiotemporal features of ECG data are all important factors affecting the accuracy of ECG arrhythmias classification. In this article, a novel DSCSSA ECG arrhythmias classification framework is proposed. First, discretewavelet transform (DWT) is used to denoise and reconstruct ECG signals to improve the feature extraction ability of ECG signals.Then, the synthetic minority oversampling technique (SMOTE) oversampling method is used to synthesize a new minority sample ECG signal to reduce the impact of ECG data imbalance on classification. Finally, a convolutional neural network (CNN) and sequence-to-sequence (Seq2Seq) classification model with attention mechanism based on bi directional long short-term memory(Bi-LSTM) as the codec is used for arrhythmias classification, and the model can give corresponding weight according to the importance of heartbeat features and can improve the ability toextract and filter the spatiotemporal features of heartbeats. In the classification of five heartbeat types, including normal beat (N), supraventricular ectopic beat (S), ventricular ectopic beat (V),fusion beat (F), and unknown beat (Q), the proposed method achieved the overall accuracy (OA) value and Macro-F1 score of 99.28% and 95.70%, respectively, in public the Massachusetts Institute of Technology - Boston’s Beth Israel Hospital (MIT-BIH)arrhythmia database. These methods are helpful to improve the effectiveness and clinical reference value of computer-aided ECG automatic classification diagnosis.
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| 26. |
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| 27. |
- Raj, Rishabh, et al.
(författare)
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A Novel Cost-Effective Magnetic Characterization Tool for Soft Magnetic Materials Used in Electrical Machines
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9456 .- 1557-9662. ; 70
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Tidskriftsartikel (refereegranskat)abstract
- Energy losses during the magnetization process of soft magnetic laminations depend on the excitation waveform. Manufacturers of magnetic materials may not provide lasses for different excitation waveforms. This may affect the accuracy of the predicted losses which are used to estimate the performance of electrical equipment during the predesign stage. Thus, a characterization tool which is capable of measuring hysteresis loops under controlled magnetization is required. Digital characterization systems available in literature use expensive commercial power amplifiers. In this work, a cost-effective power amplifier circuit is developed and interfaced with a LabVIEW program to characterize soft magnetic materials. The measurements for a sinusoidal excitation from the proposed setup are validated with those from a standard commercial measuring setup. The system is also used to measure hysteresis loops for arbitrary magnetization conditions (magnetic flux density (B) with harmonics). The proposed setup can operate over a frequency range 35-500 Hz. A small Epstein frame is also designed for measurements at higher frequencies (>200 and <500 Hz). A provision is also made to predict three components of dynamic hysteresis lasses at any frequency in the above range using the loss separation approach. This capability of the setup enables the user to predict the losses at frequencies beyond the capability of the tool. The predicted losses using this algorithm are validated with measured losses. The proposed setup is cost-effective and can be developed easily using basic electronic components.
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| 28. |
- Rinaldi, S., et al.
(författare)
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Design of a Time Dissemination System Using Chirp Modulation for Medium Voltage Smart Grid Applications
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:9, s. 6686-6695
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Tidskriftsartikel (refereegranskat)abstract
- The monitoring and the management of smart grid require an advanced communication infrastructure. The time synchronization is among the most important services such an infrastructure should offer. Several solutions are available to disseminate the time information in a distributed system; for instance, most of the times a global positioning system (GPS) receiver is used to recover accurate time information. However, GPS receivers need a clear view of the sky. Other solutions, like the use of a network-based synchronization mechanism, require a dedicated communication infrastructure, which is not always feasible for economical reason. Thus, the use of the power grid itself to disseminate a time signal is extremely interesting. The aim of this article is to investigate the possibility to distribute a time signal over a medium voltage (MV) grid using a chirp-based modulation. The timing data are coded using IRIG-B time code. Such an approach does not require the installation of a dedicated infrastructure, and it is noninvasive, because the signal is transmitted on a different band with the respect to power line communication (PLC). The effectiveness of the approach has been experimentally evaluated on a test MV line available in a laboratory. Although the tested chirp-based symbol has a limited frequency bandwidth (80 kHz), the jitter in the identification of the start of frame is on the order of 7.5 μ s, fulfilling the requirements of the most smart grid applications. © 1963-2012 IEEE.
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| 29. |
- Ruggiero, A., et al.
(författare)
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Accurate Measurement of Reciprocating Kinetic Friction Coefficient through Automatic Detection of the Running-In
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:5, s. 2398-2407
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Tidskriftsartikel (refereegranskat)abstract
- Tribological tests are adopted to estimate the kinetic friction coefficient (COF) of the material of interest according to the American Society for Testing and Materials (ASTM) standard. Typically, for the measurement process, several replicas, as well as a postprocessing data treatment, are necessary to take into account the observed casual variability of the measurand. This article describes a statistical approach aiming to highlight the running-in phase and the most significant time intervals during the steady-state for each test replica. A two-steps procedure based on the adoption of the bootstrap method allows the automatic detection of the running-in time interval and the outlier filtering of the steady-state. Experimental activity has been carried out by performing multiple tests through the ball-on-flat tribometer in order to verify the improvement allowed by the authors' proposal about the dry friction COF measurement in terms of both accuracy and repeatability. © 1963-2012 IEEE.
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| 30. |
- Rydblom, Stefani Alita Leona, 1975-, et al.
(författare)
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Measurement of atmospheric icing and droplets
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:8, s. 5799-5809
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Tidskriftsartikel (refereegranskat)abstract
- Icing conditions including atmospheric liquid water content (LWC) and size distribution of droplets were recorded close to the top of Mt. Åreskutan, 1260-m above sea level, Sweden, a place known for frequent severe icing. The findings are comparatively analyzed. Combitech IceMonitor was used to measure the ice load, and HoloOptics T41 was used to measure the atmospheric icing rate. A method to translate the digital output from HoloOptics T41 to a value between 0 and 100 is described and used. Two instruments were used for measuring LWC and the median volume diameter (MVD). We created a model of icing intensity based on the k-nearest neighbor (KNN) using wind speed, LWC, and MVD as input. The result indicates that more learning data decrease the error. An heuristic model of erosion/ablation was added to simulate the ice load, and the result was compared with that of the standard Makkonen ice load model. The Makkonen model is suitable for estimating the ice load using a 1-h temporal resolution. With a 1-min temporal resolution, the erosion/ablation needs to be modeled and included. Our observations show that conditions can alternate between icing and erosion/ablation within 1 min during an icing event.
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| 31. |
- Salles, Rafael S., et al.
(författare)
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Analytics of Waveform Distortion Variations in Railway Pantograph Measurements by Deep Learning
- 2022
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 71
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Tidskriftsartikel (refereegranskat)abstract
- Waveform distortion in general represent a widespread problem in electrified transports due to interference, service disruption, increased losses and ageing of components. Given the multitude of moving sources and the extremely variable operating conditions, short time records must be considered for analysis, and this increases in turn its complexity, from which the need for effective automated processing, as offered by a deep learning (DL) approach. This paper proposes an application of unsupervised DL to measurements of railway pantograph quantities to identify waveform distortion patterns. Data consists of pantograph current from a Swiss 15 kV 16.7 Hz railway system. Three DL input types are considered: waveforms, harmonic spectra, and supraharmonic spectra. The applied DL method applied is the deep autoencoder (DAE) followed by feature clustering, using techniques to define a suitable number of clusters. Short-term distortion is evaluated over sub-10 min intervals of harmonic and supraharmonic spectra down to sub-second intervals. Results are explained among others by connecting the distribution of the clusters (determined by self-supervised method) to the dynamic operating conditions of the rolling stock. Resulting DAE performance are superior in terms of accuracy and comprehensiveness of spectral components compared to a more traditional principal component analysis (PCA) that was chosen as reference for comparison.
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| 32. |
- Samanta, Anik Kumar, et al.
(författare)
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Minimum Distance-Based Detection of Incipient Induction Motor Faults Using Rayleigh Quotient Spectrum of Conditioned Vibration Signal
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- In this article, we propose a single-vibration sensor-based method for detecting incipient faults in squirrel cage induction motors (SCIMs). We consider defects in different parts of the bearing (inner raceway, outer raceway, cage train, and rolling element) and in a single bar of the rotor. The vibration signal is dominated by the fundamental rotational frequency and its harmonics. The dominant components result in numerical errors while estimating the relatively indistinct fault-specific spectral components. In this article, we precondition the vibration signal by suppressing multiple dominant components using an extended Kalman filter-based method. The suppression of the dominant components reduces the spectral leakage, exposes minute fault components, and improves the overall amplitude estimation. Subsequently, we estimate the fault frequency and amplitude using an accurate and low-complexity Rayleigh-quotient-based spectral estimator. The thresholds for fault detection are determined from a small number of healthy data, and an adaptive minimum distance-based detector is used for hypothesis testing. The proposed test improves detection and reduces false alarms under noisy conditions. We test the complete algorithm using data from a 22-kW SCIM laboratory setup. The proposed method has achieved 100% accuracy with the publicly available 12-kHz drive-end bearing data from Case Western Reserve University, Cleveland, OH, USA.
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| 33. |
- Shereen, Ezzeldin, et al.
(författare)
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Feasibility of Time-Synchronization Attacks Against PMU-Based State Estimation
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 69:6, s. 3412-3427
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Tidskriftsartikel (refereegranskat)abstract
- The emerging measurement technology of phasor measurement units (PMUs) makes it possible to estimate the state of electrical grids in real time, thus opening the way to new protection and control applications. PMUs rely on precise time synchronization; therefore, they are vulnerable to time-synchronization attacks (TSAs), which alter the measured voltage and current phases. In particular, undetectable TSAs pose a significant threat as they lead to an incorrect but credible estimate of the system state. Prior work has shown that such attacks exist against pairs of PMUs, but they do not take into consideration the clock adjustment performed by the clock servo, which can modify the attack angles and make the attacks detectable. This cannot be easily addressed with the existing attacks, as the undetectable angle values form a discrete set and cannot be continuously adjusted as would be required to address the problems posed to the attacker by the clock servo. Going beyond prior work, this article first shows how to perform undetectable attacks against more than two PMUs, so that the set of undetectable attacks forms a continuum and supports small adjustments. Second, it shows how an attacker can anticipate the operation of the clock servo while achieving her attack goal and remaining undetectable. Third, this article shows how to identify vulnerable sets of PMUs. Numerical results on the 39-bus IEEE benchmark system illustrate the feasibility of the proposed attack strategies.
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| 34. |
- Sisinni, Emiliano, et al.
(författare)
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Full-Analog Parasitic Capacitance Compensation for AC-Excited Differential Sensors
- 2020
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers Inc.. - 0018-9456 .- 1557-9662. ; 69:8, s. 5890-5899
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Tidskriftsartikel (refereegranskat)abstract
- Capacitive sensors are popular, especially due to the possibility to be integrated together with the readout circuit. In particular, differential implementations are intrinsically insensitive to common-mode noise. Unfortunately, stray capacitances can significantly alter the sensor output value, worsening the performance. This article proposes a novel solution based on an autotuning feedback loop to compensate for parasitic effects, thus preserving measurement performance. In particular, a voltage-controlled negative impedance converter is driven by a feedback loop, in order to control the current flowing in the sensor. The proposed solution can work with the both linear and hyperbolic type of sensors and with any voltage-mode sensor interfaces. An experimental setup, comprising the proposed compensating circuit, a De-Sauty bridge-based sensor front end and an emulated sensor, has been arranged to evaluate obtainable performance. Results show that the linearity error is decreased from more than 10%, without compensation, to less than 1%, when the proposed system is applied. © 1963-2012 IEEE.
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| 35. |
- Song, Yang, et al.
(författare)
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Contact Wire Irregularity Stochastics and Effect on High-Speed Railway Pantograph-Catenary Interactions
- 2020
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0018-9456 .- 1557-9662. ; 69:10, s. 8196-8206
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Tidskriftsartikel (refereegranskat)abstract
- In high-speed rail operations, contact wire irregularity (CWI) in a catenary is a common disturbance to the pantograph-catenary interaction performance, which directly affects the quality of current collection. To describe the pointwise stochastics of CWI, the power spectral density (PSD) function for CWI is proposed, and its effect on the pantograph-catenary interaction is investigated. First, a preprocessing procedure is proposed to eliminate the redundant information in the measured irregularities based on the ensemble empirical mode decomposition (EEMD). Then, the upper envelope of the irregularity, which contains all the information regarding the dropper positions on the contact wire, is extracted. A form of the PSD function is suggested for contact wire irregularities. A methodology is proposed to include the effect of random irregularities in the assessment of the interaction performance of a pantograph-catenary. A developed target configuration under dead load (TCUD) method is used to calculate the initial configuration of the catenary, in which the dropper points on the contact wire are placed on their exact positions. Finally, the effect of the random contact wire irregularities on the contact force is investigated through 500 numerical simulations at each operating speed. The present results indicate that random irregularities have a direct impact on the pantograph-catenary contact, including an increment in the dispersion of the contact force statistics. The stochastic analysis shows that over 70% of the results with irregularities are worse than the ideal result without irregularities.
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| 36. |
- Verma, Shalin, et al.
(författare)
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Measurements and Characterization of a Newly Developed Novel Miniature WIPT System
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- This article reports, for the first time, the design and experimental evaluation of a compact wireless information and power transfer (WIPT) system operating at radio frequency (RF). The design of WIPT system is facilitated by the development of a novel tri-band defected ground structure (DGS) based bandstop filter (BSF) operating at three different frequencies of 300, 433, and 700 MHz. Then, two similar BSFs are arranged in a back-to-back configuration to achieve near-field resonant inductive coupling for transfer of information and power. The measurement carried out on a prototyped system shows an excellent agreement between the measured and simulation results and provides power transfer efficiencies of 70.1%, 66%, and 65% at 300, 433, and 700 MHz, respectively, at a separation distance of 23 mm. These figures are a significant advancement over the existing state of the art. Furthermore, up-link and down-link of data transfer at 433 and 700 MHz are demonstrated using universal software radio peripheral (USRP), and power transfer is shown by illuminating a light emitting diode (LED) at 300 MHz.
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| 37. |
- Wang, Yifan, et al.
(författare)
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Composite Data Driven-based Adaptive Control for a Piezoelectric Linear Motor
- 2022
-
Ingår i: IEEE Transactions on Instrumentation and Measurement. - 1557-9662 .- 0018-9456. ; 71
-
Tidskriftsartikel (refereegranskat)abstract
- Piezoelectric linear motors play an important role in ultra-precision manufacturing technology. However, the complex nonlinear relationship between the input and output of the piezoelectric linear motors limits their further application. In this paper, to achieve precise motion control for a piezoelectric linear motor, a composite data driven-based adaptive control method is proposed, consisting of a correction controller, model free adaptive controller (MFAC), and low pass filter. The proposed control method addresses the demand for a precise model of the piezoelectric linear motor and solely relies on the linear model and input/output measurement data. First, an experimental test is implemented to analyze the complex nonlinearity between input and output signals of the controlled system, and a correction control is employed based on the dynamic linear sub-model of the piezoelectric linear motor to improve its dynamic and static characteristics. Then, to avoid the influence of unmodeled dynamics, such as inherent nonlinearity and external vibration, a MFAC is established as a feedback controller using data driven technology. In addition, a low pass filter is incorporated into the feedback loop to eliminate high frequency measurement noise in the system, thus improving the transient response of the MFAC method. Finally, the theoretical analysis of the error convergence is presented. The effectiveness of the proposed method is verified via comparisons with a correction control method, correction control-based digital sliding-mode control method, and correction control-based MFAC method. The experimental results indicate that the proposed control method is suitable for engineering applications. In particular, the root-mean-square error (RMSE) for the third-order S-curve tracking using the proposed is reduced by more than 15%, compared with the RMSEs for the cases with contrast control methods.
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| 38. |
- Wang, Zengkun, et al.
(författare)
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Min-Max Probe Placement and Extended Relaxation Estimation Method for Processing Blade Tip Timing Signals
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 72
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Tidskriftsartikel (refereegranskat)abstract
- Measuring blade displacement using blade tip timing (BTT) enables nonintrusive monitoring of rotating blades and their vibration frequencies. The average sampling frequency of BTT is the product of the number of measurement probes and rotational frequency, which is usually far less than the blade natural frequency due to the limited number of probes. The pattern of the aliasing that arises from under-sampling is rather complex under uneven probe placement. In this article, we consider a probe placement design that is based on minimizing the maximum sidelobe level of the spectral window to suppress the aliasing frequencies in the spectrum. Based on a signal model containing both asynchronous and synchronous sinusoids, we then develop an extended version of the RELAX method (ERELAX) to estimate their parameters simultaneously. Model order selection rules are also used to determine the number of asynchronous sinusoids. The frequency ambiguity that arises from periodic nonuniform sampling (PNS) is also discussed based on the convolution in the frequency domain. Numerical simulations and results of a curved-blade experiment show that the proposed method has a mean squared estimation error less than 25% of that of two state-of-the-art methods (Block-OMP and MUSIC), requires 40% of the data length needed by the latter methods to achieve the same estimation accuracy, and has the smallest standard deviation of the reconstruction errors. Simulation codes are available at https://github.com/superjdg/RELAX_BTT.
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| 39. |
- Xue, Wei, et al.
(författare)
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A Unified Approach for Uncertainty Analyses for Total Radiated Power and Total Isotropic Sensitivity Measurements in Reverberation Chamber
- 2021
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - 1557-9662 .- 0018-9456. ; 70
-
Tidskriftsartikel (refereegranskat)abstract
- With the rapid development and explosive application of the Internet of Things (IoT) technology, IoT devices become ubiquitous and indispensable in people’s daily lives. IoT devices with various forms and massive production impose challenges on their over-the-air (OTA) testing. Nowadays, conducting OTA testing in an efficient, reliable, and cost-effective way has become an urgent demand for the IoT industry. Owing to the particular properties (e.g., low cost, high efficiency, and good repeatability) of the reverberation chamber (RC), it has become a popular OTA testing facility. This paper analyzes the statistical uncertainties of two fundamental metrics for IoT devices, i.e., the total radiated power (TRP) and the total isotropic sensitivity (TIS), measured in the RC. Based on the derived probability density functions (PDFs) and associate statistics, a unified approach for uncertainty analyses of TRP and TIS has been proposed, which can greatly facilitate the uncertainty characterizations in the OTA testing.
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| 40. |
- Zhang, Yinlong, et al.
(författare)
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GCMVF-AGV : Globally Consistent Multiview Visual-Inertial Fusion for AGV Navigation in Digital Workshops
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9456 .- 1557-9662. ; 72
-
Tidskriftsartikel (refereegranskat)abstract
- An accurate and globally consistent navigation system is crucial for estimating the positions and attitudes of automated guided vehicles (AGVs) in digital workshops. A promising navigation technology for this purpose is tightly coupled visual-inertial fusion, which offers advantages such as quick response (QR), absolute scale, and accuracy. However, existing visual-inertial fusion systems have limitations, including long-term drift, tracking failures in textureless or poorly illuminated environments, and a lack of absolute references. To create a reliable and consistent AGV navigation framework and correct for long-term drift, we have designed a novel framework, globally consistent multiview visual-inertial fusion for AGV navigation (GCMVF-AGV). This framework uses a downward-looking QR vision sensor and a forward-looking visual-inertial sensor together to estimate AGV poses in real time. The downward camera provides absolute AGV positions and attitudes with reference to the global workshop frame. Furthermore, long-term visual-inertial drift, inertial biases, and velocities are periodically compensated between spatial intervals of QR codes by minimizing visual-inertial residuals with the rigid constraints of absolute poses estimated from the downward visual measurements. We have evaluated the proposed method on the developed AGV navigation platform, and experimental results demonstrate the position and attitude errors of less than 0.05 m and 2 degrees, respectively.
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| 41. |
- Zhang, Yuxuan, et al.
(författare)
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Leveraging Acoustic Emission and Machine Learning for Concrete Materials Damage Classification on Embedded Devices
- 2023
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Ingår i: IEEE Transactions on Instrumentation and Measurement. - : IEEE. - 0018-9456 .- 1557-9662. ; 72
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Tidskriftsartikel (refereegranskat)abstract
- For the field of structural health monitoring (SHM), acoustic emission (AE) technology is important as a damage identification technique that does not cause secondary damage to concrete. Nowadays, applications of non-destructive concrete damage identification are mostly limited to commercial software or identification algorithms running on desktop computers. It has so far not been deployed in low-power embedded devices. In this study, a lightweight convolutional neural network (CNN) model for online non-destructive damage type recognition of concrete materials is presented and deployed on a resource-constrained microcontroller unit as a tiny machine learning (TinyML) application. The CNN model uses raw acoustic emission signals as input and damage recognition types as output. 15,000 acoustic emission signals are used as data sets divided into training, validation, and test sets in the ratio of 8:1:1. The experimental results show that an accuracy of 99.6% is achieved on the nRF52840 microcontroller (ARM Cortex M4) with only 166.822 ms and 0.555mJ for a single inference using only 20K parameters and 30.5KB model size. This work demonstrates the effectiveness and feasibility of the proposed model, which achieves a trade-off between high classification accuracy and deployability on resource-constrained MCUs. Consequently, it provides strong support for online continuous non-destructive structural health monitoring.
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