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1.
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2.
  • Ahmad, Jawad, 1985-, et al. (författare)
  • Screen Printed Piezoresistive Sensors for Monitoring Pressure Distribution in Wheelchair
  • 2019
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 19:6, s. 2055-2063
  • Tidskriftsartikel (refereegranskat)abstract
    • Prolonged sitting inadequacies cause pressure ulcer to many individuals, especially to disadvantaged with reduced mobility. The measurement of distributed pressure and detection of irregular sitting postures is essential for preventing the risk of developing pressure ulcer. In this paper, a pressure sensing system capable of recognizing sitting postures by means of measuring interface pressure through printed pressure sensors is presented. A thin and flexible large area sensor is screen-printed using silver flake and carbon particle inks and comprises 16 sensing elements. For the evaluation of practical usability, the sensor characterization is carried out by conducting stability, repeatability, drift and bending tests. The performance of the sensor is checked under varying environmental conditions. Sitting posture detection accuracy above 80 % is achieved using a classification algorithm for four different sitting postures. Pressure distribution is monitored at a scanning rate of 10 Hz. A low power and small form factor of read-out electronics enables a compact packaging inside the seat cushion. The presented sensor design targets smart wheelchairs, but it is extendable to much larger areas, for example to be used in beds. The proposed sensing system would be of a great assistance for caregivers and health professionals.
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3.
  • Ahmed, Mohammad Faisal, et al. (författare)
  • Privacy-Preserving Distributed Beamformer Design Techniques for Correlated Parameter Estimation
  • 2023
  • Ingår i: IEEE Sensors Journal. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 1530-437X .- 1558-1748. ; 23:21, s. 26728-26739
  • Tidskriftsartikel (refereegranskat)abstract
    • Privacy-preserving distributed beamforming designs are conceived for temporally correlated vector parameter estimation in an orthogonal frequency division multiplexing (OFDM)-based wireless sensor network (WSN). The temporal correlation inherent in the parameter vector is exploited by the rate distortion theory-based bit allocation framework used for the optimal quantization of the sensor measurements. The proposed distributed beamforming designs are derived via fusion of the dual consensus alternating direction method of multiplier (DC-ADMM) technique with a pertinent privacy-preserving framework. This makes it possible for each sensor node (SN) to design its transmit precoders in a distributed fashion, which minimizes the susceptibility of vital information to malicious eavesdropper (Ev) nodes, while simultaneously avoiding the significant communication overhead required by a centralized approach for the transmission of the state information to the fusion center (FC). The Bayesian Cramer-Rao bound (BCRB) is derived for benchmarking the estimation performance of the proposed transmit beamformer and receiver combiner designs, while our simulation results illustrate the performance and explicitly demonstrate the trade-off between the privacy and estimation performance.
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4.
  • Akbarzadeh, Saeed, et al. (författare)
  • A Simple Fabrication, Low Noise, Capacitive Tactile Sensor for Use in Inexpensive and Smart Healthcare Systems
  • 2022
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 22:9, s. 9069-9077
  • Tidskriftsartikel (refereegranskat)abstract
    • Tactile sensors are among the most important devices used in industrial and biomedical fields. Sensors' profiles are significantly affected by their structures and material used. This article presents a robust, low-cost, low noise, accurate and simple fabrication capacitive tactile sensor as a single taxel fabricated on foam. This highly scalable design provides excellent noise immunity, accuracy, and due to a unique printable elastic conductor, it is flexible and stretchable with more than 200% strain. Furthermore, the taxel is based on the capacitive Wheatstone bridge. As a result, noise immunity and stability in case of temperature fluctuation is accomplished. Additionally, the sensor's innovative, simple fabrication, made of Polyurethane foam and printable elastic conductor, allows the system to adapt and achieve relevant results necessary for the purpose of the sensor's application. Therefore, the proposed sensor has potential applications in industrial and biomedical contexts, such as sleep monitoring, etc.
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5.
  • Alam, Mohammad Anzar, et al. (författare)
  • Limitation of a line-of-light online paper surface measurement system
  • 2014
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:8, s. 2715-2724
  • Tidskriftsartikel (refereegranskat)abstract
    • A new prototype device has been developed based on a laser triangulation principle to measure online surface topography in the paper and paperboard industries. It characterizes the surface in a wide spatial scale of topography from 0.09-10 mm. The prototype's technique projects a narrow line-of-light perpendicularly onto the moving paper-Web surface and scattered reflected light is collected at a low angle, low specular, and reduced coherent length onto the CCD sensors synchronized with the laser sources. The scattering phenomenon determines surface deviations in the z-direction. The full-width, at half-maximum of a laser line in cross section is sensitive in computation of the surface topography. The signal processing aspect of the image processing, for example, threshold and filtering algorithms are also sensitive in estimating the accurate surface features. Moreover, improper light illumination, intensity, reflection, occlusion, surface motion, and noise in the imaging sensor, and so forth, all contribute to deteriorate the measurements. Optical techniques measure the surface indirectly and, in general, an evaluation of the performance and the limitations of the technique are both essential and challenging. The paper describes the accuracy, uncertainty, and limitations of the developed technique in the raw profiles and in terms of the rms roughness. The achieved image subpixel resolution is 0.01 times a pixel. Statistically estimated uncertainty (2σ) in the laboratory environment was found 0.05 μm for a smooth sample, which provides a 95% confidence level in the rms roughness results. The depth of field of the prototype is ~2.4 mm.
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6.
  • Alam, Mohammad Anzar, et al. (författare)
  • Real time surface measurement technique in a wide range of wavelengths spectrum
  • 2014
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:1, s. 285-294
  • Tidskriftsartikel (refereegranskat)abstract
    • Real time surface topography measurement in the paper and paperboard industries is a challenging research field. The existing online techniques measure only a small area of paper surface and estimate topographical irregularities in a narrow scale as a single predictor. Considering the limitations and complications in measuring the surface at high speed, a laser line triangulation technique is explored to measure surface topography in a wide scale. The developed technique is new for the paper and paperboard application that scans a line onto the paper-web surface up to 210 mm in length in the cross machine direction. The combination of a narrow laser linewidth imaging, a subpixel resolution, and the selection of a unique measurement location has made it possible to measure roughness and simultaneously characterize paper surface topography from 0.1 to 30 mm spatial wavelength. This spatial range covers wide scale surface properties such as roughness, cockling, and waviness. The technique clearly distinguishes and characterizes the surface of newspaper, and lightweight coated, coated, and uncoated paperboard in real time during the paper manufacturing process. The system temporal noise for the average roughness is estimated as 37 dB. The signal to noise ratio found is from 5.4 to 8.1 in the short spatial wavelength up to 1 mm, whereas it is more than 75 in the long spatial wavelength from 5 to 10 mm.
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7.
  • Alhashimi, Anas, 1978-, et al. (författare)
  • Calibrating distance sensors for terrestrial applications without groundtruth information
  • 2017
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 17:12, s. 3698-3709
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper describes a new calibration procedure for distance sensors that does not require independent sources of groundtruth information, i.e., that is not based on comparing the measurements from the uncalibrated sensor against measurements from a precise device assumed as the groundtruth. Alternatively, the procedure assumes that the uncalibrated distance sensor moves in space on a straight line in an environment with fixed targets, so that the intrinsic parameters of the statistical model of the sensor readings are calibrated without requiring tests in controlled environments, but rather in environments where the sensor follows linear movement and objects do not move. The proposed calibration procedure exploits an approximated expectation maximization scheme on top of two ingredients: an heteroscedastic statistical model describing the measurement process, and a simplified dynamical model describing the linear sensor movement. The procedure is designed to be capable of not just estimating the parameters of one generic distance sensor, but rather integrating the most common sensors in robotic applications, such as Lidars, odometers, and sonar rangers and learn the intrinsic parameters of all these sensors simultaneously. Tests in a controlled environment led to a reduction of the mean squared error of the measurements returned by a commercial triangulation Lidar by a factor between 3 and 6, comparable to the efficiency of other state-of-the art groundtruth-based calibration procedures. Adding odometric and ultrasonic information further improved the performance index of the overall distance estimation strategy by a factor of up to 1.2. Tests also show high robustness against violating the linear movements assumption.
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8.
  • Alqaysi, Hiba, et al. (författare)
  • Cost Optimized Design of Multi-Camera Domefor Volumetric Surveillance
  • 2021
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 21:3, s. 3730-3737
  • Tidskriftsartikel (refereegranskat)abstract
    • A multi-camera dome consists of number ofcameras arranged in layers to monitor a hemisphere aroundits center. In volumetric surveillance,a 3D space is required tobemonitoredwhich can be achievedby implementing numberof multi-camera domes. A monitoring height is consideredas a constraint to ensure full coverage of the space belowit. Accordingly, the multi-camera dome can be redesignedinto a cylinder such that each of its multiple layers hasdifferent coverage radius. Minimum monitoring constraintsshould be met at all layers. This work is presenting a costoptimized design for the multi-camera dome that maximizesits coverage. The cost per node and number of squaremetersper dollar of multiple configurations are calculated using asearch space of cameras and considering a set of monitoring and coverage constraints. The proposed design is costoptimized per node and provides more coverage as compared to the hemispherical multi-camera dome.
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9.
  • An, Sining, 1991, et al. (författare)
  • Micrometer Accuracy Phase Modulated Radar for Distance Measurement and Monitoring
  • 2020
  • Ingår i: IEEE Sensors Journal. - 1558-1748 .- 1530-437X. ; 20:6, s. 2919-2927
  • Tidskriftsartikel (refereegranskat)abstract
    • An enhanced accuracy random binary phase modulated radar is proposed. It can be used in high accuracy monitoring in manufacturing. Compared with the traditional high accuracy radar using frequency modulated continuous wave (FMCW), the proposed radar system can be used in a multi-user scenario without occupying more bandwidth. A two-step distance estimation method is introduced to estimate the distance. First, the distance estimation accuracy is narrowed down to a half carrier wavelength by analyzing the envelope of the phase modulated signal. Then the carrier phase information increases the distance accuracy to several micrometers. An equalization method is introduced to solve the I/Q imbalance problem. The proposed radar system is demonstrated at a carrier frequency of 80 GHz with a bandwidth of 2 GHz. The measured distance error was within ±7 μm. In addition, a high measurement repetition rate of 500 kHz was reached which is suitable for real-time monitoring in automatic manufacturing.
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10.
  • Andersson, Henrik, et al. (författare)
  • Inkjet printed silver nanoparticle humidity sensor with memory effect on paper
  • 2012
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:6, s. 1901-1905
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • In this paper, the design and the manufacture of an inkjet printed resistive type humidity sensor on paper are reported. After having been exposed to humidity above a given threshold level, the resistance of the sensor decreases substantially and remains at that level even when thehumidity is reduced. It is possible to deduce the humidity level by monitoring the resistance. The main benefit of the printed sensor presented in this case is in relation to its very low production costs. It has also been shown that both the ink type and this paper combination used prove to be crucial in order to obtain the desired sensor effect. More research is required in order to fully understand the humidity sintering effect on the nano particle ink and the role of the substrate. However, the observed effect can be put to use in printed humidity sensors which possess a memoryfunction. The sensor can be used in various applications for environmental monitoring, for example, in situations where a large number of inexpensive and disposable humidity sensors are required which are able to detect whether they have been subjected to high humidity. This could be the checking of transportation conditions of goods or monitoring humidity within buildings. © 2001-2012 IEEE.
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11.
  • Andersson, Henrik, et al. (författare)
  • Investigation of Humidity Sensor Effect in Silver Nanoparticle Ink Sensors Printed on Paper
  • 2014
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:3, s. Art. no. 6615915-
  • Tidskriftsartikel (refereegranskat)abstract
    • Thin inkjet-printed tracks of silver nanoparticles have previously been observed to show a non-reversible decrease in resistance when exposed to a high degree of relative humidity and thus providing sensor functionality with a memory effect. This paper provides a more in-depth explanation of the observed humidity sensor effect that originates from inkjet-printed silver nanoparticle sensors on a paper substrate. It is shown that the geometry of the sensor has a large effect on the sensor's initial resistance, and therefore also on the sensor's resistive dynamic range. The importance of the sensor geometry is believed to be due to the amount of solvent from the ink interacting with the coating of the paper substrate, which in turn enables the diffusion of salts from the paper coating into the ink and thus affecting the silver ink.
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12.
  • Andersson, Henrik, et al. (författare)
  • Processing and Characterization of a MOS Type Tetra Lateral Position Sensitive Detector with Indium Tin Oxide Gate Contact
  • 2008
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:9-10, s. 1704-1709
  • Tidskriftsartikel (refereegranskat)abstract
    • A 2-D tetra lateral position sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) principle has been manufactured and characterized. The active area of the device is 5 nun x 5 mm and the intention is to use the central 4 nun x 4 nun for low nonlinearity measurements. The gate contact is made of indium tin oxide (ITO) that is a degenerate electrically conducting semiconductor, which, in addition, is also transparent in the visible part of the spectrum. The use of a MOS structure results in a processing with no necessity to use implantation or diffusion in order to make the resistive p-layer as in a conventional p-n junction lateral effect PSD. Position measurements show good linearity in the middle 4 nun x 4 mm area. Within the middle 2.1 mm x 2.1 mm, the nonlinearity is within 1.7% of the active area with a position detection error of maximum 60 mu m. Measured MOS IV characteristics are compared to a level 3 spice model fit and show good agreement. The threshold voltage is determined to be -0.03 V. Responsivity measurements show a high sensitivity in the visible spectral region.
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13.
  • Anderås, Emil, 1982-, et al. (författare)
  • Tilted c-Axis Thin-Film Bulk Wave Resonant Pressure Sensors With Improved Sensitivity
  • 2012
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:8, s. 2653-2654
  • Tidskriftsartikel (refereegranskat)abstract
    • Aluminum nitride thin film bulk wave resonant pressure sensors employing c- and tilted c-axis texture, have been fabricated and tested for their pressure sensitivities. The c-axis tilted FBAR pressure sensors demonstrate substantially higher pressure sensitivity compared to its c-axis oriented counterpart. More specifically the thickness plate quasi-shear resonance has demonstrated the highest pressure sensitivity while further being able to preserve its performance in liquid environment.
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14.
  • Arapan, Lilia, et al. (författare)
  • Sensitivity Features of Thin Film Plate Acoustic Wave Resonators
  • 2011
  • Ingår i: IEEE Sensors Journal. - : IEEE Sensors Council. - 1530-437X .- 1558-1748. ; 11:12, s. 3330-3331
  • Tidskriftsartikel (refereegranskat)abstract
    • Thin film plate acoustic resonators devices operating in the lowest order symmetric Lamb wave mode (S0) in coriented aluminum nitride (AlN) membranes on Si were fabricated and tested for their sensitivities to pressure and mass as well as for their ability to work in liquid environment.
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15.
  • Aroutiounian, Vladimir M., et al. (författare)
  • Noise spectroscopy of gas sensors
  • 2008
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 8:5-6, s. 786-790
  • Tidskriftsartikel (refereegranskat)abstract
    • We study current-voltages and low-frequency noise characteristics of the metal-porous silicon-silicon single crystal-metal structure with 50% and 73% porosity of porous silicon. The study is performed in dry air and in a mix of dry air with carbon monoxide of different concentrations. The Hooge noise parameter alpha(H) and the parameter gamma in the frequency dependence of the noise voltage spectral density S-U (f) were determined from experimental data. High sensitivity of spectral dependence of noise to gas concentration allows offering powerful method for determination of gas concentration in the air or environment.
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16.
  • Ashraf, Shakeel, 1984-, et al. (författare)
  • Fabrication and characterization of a SU8-epoxy membrane based thermopile detector with an integrated multilayered absorber structure for the mid-IR region
  • 2019
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 19:11, s. 4000-4007
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper reports on the fabrication and characterization of a thermopile detector with an integrated mid-infrared absorber structure. The fabricated absorber structure has shown an absorption of more than 95% in the wavelength range of 3.2 – 5.47 μm. The detector was fabricated with standard cleanroom process techniques and equipment. The serial resistance was measured at about 315 kΩ at room temperature. The photosensitivity of the detector was characterized for a signle wavelength (4.26 µm) and a band of wavelength ranging from 2.5 –5.5 µm through two different measurement setups. In the first measurement setup, the photosensitivity was estimated at 57.5 V·mm2·W-1 through a MEMS-based infrared radiation source and with an optical band-pass filter of wavelength 4.26µm. The following characterization was performed to characterise the photosensitivity of the detector in a broader wavelength range. This measurement was taken using a monochromator setup utilizing a reference photodetector for calculations of the optical power of the infrared source. The photosensitivity and the specific detectivity (D*) of the fabricated detector were measured to values of 30-92 V·W-1 and 8.0×107-2.4×108 cm·Hz1/2·W-1, respectively, in the wavelength range of 2.8 – 5 µm. The time constant was estimated to around 21 ms
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17.
  • Athalye, Akshay, et al. (författare)
  • Novel Semi-Passive RFID System for Indoor Localization
  • 2013
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 13:2, s. 528-537
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we present a novel semi-passive radio-frequency identification (RFID) system for accurate indoor localization. The system is composed of a standard ultra high frequency (UHF) ISO-18000-6C compliant RFID reader, a set of standard passive RFID tags whose locations are known, and a newly developed tag-like RFID component, which is attached to the items that need to be localized. The new semi-passive component, referred to as sensatag (sense-a-tag), has a dual functionality: it can sense and decode communication between the reader and standard tags in its proximity, and can communicate with the reader like standard tags using backscatter modulation. Based on the information conveyed by the sensatags to the reader, localization algorithms based on binary sensor principles can be developed. We conduct a number of experiments in a laboratory to quantify the performance of our system, including two real applications, one finding the exact placement of items on shelves, and the other estimating the direction of item movement.
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18.
  • Athanasiou, Vasileios, 1988, et al. (författare)
  • On Sensing Principles Using Temporally Extended Bar Codes
  • 2020
  • Ingår i: IEEE Sensors Journal. - 1558-1748 .- 1530-437X. ; 20:13, s. 6782-6791
  • Tidskriftsartikel (refereegranskat)abstract
    • The detection of ionic variation patterns could be a significant marker for the diagnosis of neurological and other diseases. This paper introduces a novel idea for training chemical sensors to recognise patterns of ionic variations. By using an external voltage signal, a sensor can be trained to output distinct time-series signals depending on the state of the ionic solution. Those sequences can be analysed by a relatively simple readout layer for diagnostic purposes. The idea is demonstrated on a chemical sensor that is sensitive to zinc ions with a simple goal of classifying zinc ionic variations as either stable or varying. The study features both theoretical and experimental results. By extensive numerical simulations, it has been shown that the proposed method works successfully in silico. Distinct time-series signals are found which occur with a high probability under only one class of ionic variations. The related experimental results point in the right direction.
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19.
  • Barac, Filip, 1983-, et al. (författare)
  • Channel Diagnostics for Wireless Sensor Networks in Harsh Industrial Environments
  • 2014
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:11, s. 3983-3995
  • Tidskriftsartikel (refereegranskat)abstract
    • Wireless sensor network communication in industrial environments is compromised by interference, multipath fading, and signal attenuation. In that respect, accurate channel diagnostics is imperative to selecting the adequate countermeasures. This paper presents the lightweight packet error discriminator (LPED) that infers the wireless link condition by distinguishing between errors caused by multipath fading and attenuation, and those inflicted by interfering wideband single-channel communication systems (e.g., IEEE 802.11b/g), based on the differences in their error footprints. The LPED uses forward error correction in a novel context, namely, to determine the symbol error density, which is then fed to a discriminator for error source classification. The classification criteria are derived from an extensive set of error traces collected in three different types of industrial environments, and verified on a newly collected set of error traces. The proposed solution is evaluated both offline and online, in terms of classification accuracy, speed of channel diagnostics, and execution time. The results show that in ≥91% of cases, a single packet is sufficient for a correct channel diagnosis, accelerating link state inference by at least 270%, compared with the relevant state-of-the-art approaches. The execution time of LPED, for the worst case of packet corruption and maximum packet size, is below 30 ms with ≤3% of device memory consumption. Finally, live tests in an industrial environment show that LPED quickly recovers from link outage, by losing up to two packets on average, which is only one packet above the theoretical minimum.
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20.
  • Becker, Elin, et al. (författare)
  • Study of the Sensing Mechanism Towards Carbon Monoxide of Platinum-Based Field Effect Sensors
  • 2011
  • Ingår i: IEEE SENSORS JOURNAL. - : IEEE. - 1530-437X. ; 11:7, s. 1527-1534
  • Tidskriftsartikel (refereegranskat)abstract
    • We have investigated the temperature dependence and the effect of hydrogen on the CO response of MISiC field effect device sensors. The evolution of adsorbates on a model sensor was studied by in situ DRIFT spectroscopy and correlated to sensor response measurements at similar conditions. A strong correlation between the CO coverage of the sensor surface and the sensor response was found. The temperature dependence and hydrogen sensitivity are partly in agreement with these observations, however at low temperatures it is difficult to explain the observed increase in sensor response with increasing temperature. This may be explained by the reduction of a surface oxide or removal of oxygen from the Pt/SiO2 interface at increasing temperatures. The sensing mechanism of MISiC field effect sensors is likely complex, involving several of the factors discussed in this paper.
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21.
  • Becker, Elin, 1981, et al. (författare)
  • Study of the Sensing Mechanism Towards Carbon Monoxide of Platinum-Based Field Effect Sensors
  • 2011
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1558-1748 .- 1530-437X. ; 11:7, s. 1527-1534
  • Tidskriftsartikel (refereegranskat)abstract
    • We have investigated the temperature dependence and the effect of hydrogen on the CO response of MISiC field effect device sensors. The evolution of adsorbates on a model sensor was studied by in situ DRIFT spectroscopy and correlated to sensor response measurements at similar conditions. A strong correlation between the CO coverage of the sensor surface and the sensor response was found. The temperature dependence and hydrogen sensitivity are partly in agreement with these observations, however at low temperatures it is difficult to explain the observed increase in sensor response with increasing temperature. This may be explained by the reduction of a surface oxide or removal of oxygen from the Pt/SiO2 interface at increasing temperatures. The sensing mechanism of MISiC field effect sensors is likely complex, involving several of the factors discussed in this paper.
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22.
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23.
  • Biabani, Morteza, et al. (författare)
  • RBDMS : Rate-Adaptation and Buffer-Awareness Data Gathering for Mobile Sink Scheduling in WSNs
  • 2022
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers Inc.. - 1530-437X .- 1558-1748. ; 22:21, s. 21326-21341
  • Tidskriftsartikel (refereegranskat)abstract
    • Employing a mobile sink (MS) to act as a relay node in wireless sensor network (WSN) applications is a promising solution for efficient power saving and data collection. However, establishing long-distance traveling leads to larger latency or inefficient buffer management at rendezvous points (RPs), e.g., flying UAVs in disaster management. Moreover, there is no efficient solution to guarantee the completeness of data gathering by considering the waiting time (sojourn) of the MS to receive packets from RPs in addition to the MS moving time among RPs. This work presents a rate-adaptation and buffer-awareness data gathering for MS scheduling (RBDMS) by constructing grid cells in the monitoring area. In fact, it establishes the shortest path by passing within the communication range of the sensors based on data volume. RBDMS not only has a mechanism for handling emergency packets with low latency but also benefits from stochastic integer programming (SIP) for scheduling the MS sojourn time with lower computational time using Lagrangian relaxation. Simulation results confirm that the proposed RBDMS outperforms comparable state-of-the-art works in terms of the MS path length, network lifetime, the energy consumption of sensors, and MS, as well as buffering performance.
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24.
  • Bonmann, Marlene, 1988, et al. (författare)
  • Terahertz radar observes powder dynamics for pharmaceutical manufacturing
  • 2024
  • Ingår i: IEEE Sensors Journal. - 1558-1748 .- 1530-437X. ; 24:13, s. 20512-20522
  • Tidskriftsartikel (refereegranskat)abstract
    • The optical opaqueness of powders has precluded the observation of powder flow dynamics in processing tubes, with important implications, for example, in the pharmaceutical industry, where non-destructive monitoring during the manufacturing process is essential to ensure the quality of the final product and the effectiveness of the process. Taking advantage of the high penetration of terahertz electromagnetic waves in powders and its wavelength-to-particle size ratio, we demonstrate that a submillimeter-wave pulse-Doppler radar can overcome the present challenges and characterize powder flow dynamics in pharmaceutical manufacturing processes. Mimicking typical vessel shapes in pharmaceutical operations, we were able to characterize falling powder streams in a tube with a sample volume resolution of a few cubic centimeters and a range resolution of about 5 mm. We successfully monitored particle velocity, particle distribution within the tube, and mass flow rate in real-time. This remote sensing method, based on advanced terahertz electronics, opens up the possibility to study and monitor powder dynamics in a wide range of applications.
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25.
  • Brasil, M. A. B., et al. (författare)
  • Performance Comparison of Multi-Agent Middleware Platforms for Wireless Sensor Networks
  • 2018
  • Ingår i: IEEE Sensors Journal. - Piscataway, N.J. : Institute of Electrical and Electronics Engineers Inc.. - 1530-437X .- 1558-1748. ; 18:7, s. 3039-3049
  • Tidskriftsartikel (refereegranskat)abstract
    • Despite the numerous possible applications of wireless sensor networks (WSNs), there is a key disadvantage related to the high complexity in programming WSNs, which is a result of their distributed and built-in features. To overcome this shortcoming, software agents have been identified as a suitable programming paradigm. The agent-based approach commonly uses a middleware for the execution of the software agents. In this regard, the present paper aims at comparing Java-based agent middleware platforms in their performance for the WSN application domain. Experiments were performed to analyze two versions of tracking applications, based on different agent models implemented for a given set of middleware platforms that support programming at a high-level of abstraction. The results highlight the differences in the resource consumption (CPU, memory, and energy) and in the communication overhead, providing an indication of suitability for each type of analyzed middleware, considering specific concerns while developing WSN applications. © 2001-2012 IEEE.
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26.
  • Bur, Christian, et al. (författare)
  • Detecting Volatile Organic Compounds in the ppb Range with Gas Sensitive Platinum gate SiC-Field Effect Transistors
  • 2014
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 14:9, s. 3221-3228
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, the use of a platinum gate gas-sensitive SiC field-effect transistor (SiC-FET) was studied for the detection of low concentrations of hazardous volatile organic compounds (VOCs). For this purpose, a new gas mixing system was realized providing VOCs down to sub-parts per billion levels with permeation ovens and gas predilution. Benzene, naphthalene, and formaldehyde were chosen as major indoor air pollutants and their characteristics are briefly reviewed. Measurements have shown that the selected VOCs can be detected by the SiC-FET in the parts per billion range and indicate a detection limit of ~1 ppb for benzene and naphthalene and ~10 ppb for formaldehyde in humid atmospheres. For 10-ppb naphthalene at 20% r.h., the sensor response is high with 12 mV, respectively, a relative response of 1.4%. Even in a background of 2-ppm ethanol, the relative response is still 0.3%. Quantification independent of the humidity level can be achieved using temperature cycled operation combined with pattern recognition, here linear discriminant analysis. Discrimination of benzene, naphthalene, and formaldehyde is also possible.
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27.
  • Bur, Christian, et al. (författare)
  • Increasing the Selectivity of Pt-Gate SiC Field Effect Gas Sensors by Dynamic Temperature Modulation
  • 2012
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 12:6
  • Tidskriftsartikel (refereegranskat)abstract
    • Based on a diode coupled silicon carbide field effect transistor (FET) with platinum as catalytic gate material, the influence of dynamic temperature modulation on the selectivity of gas analysis sensors FETs has been investigated. This operating mode, studied intensively for semiconductor gas sensors, has only recently been applied to FETs. A suitable temperature cycle for detection of typical exhaust gases (CO, NO, C3H6, H-2, NH3) was developed and combined with appropriate signal processing. The sensor data were evaluated using multivariate statistics, e.g., linear discriminant analysis. Measurements have proven that typical exhaust gases can be discriminated in backgrounds with 0, 10, and 20% oxygen. Furthermore, we are able to quantify the mentioned gases and to determine unknown concentrations based on training data. Very low levels of relative humidity below a few percent influence the sensor response considerably but for higher levels the cross interference of humidity is negligible. In addition, experiments regarding stability and reproducibility were performed.
  •  
28.
  • Cai, Haibin, et al. (författare)
  • Sensing-enhanced Therapy System for Assessing Children with Autism Spectrum Disorders : A Feasibility Study
  • 2019
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 19:4, s. 1508-1518
  • Tidskriftsartikel (refereegranskat)abstract
    • It is evident that recently reported robot-assisted therapy systems for assessment of children with autism spectrum disorder (ASD) lack autonomous interaction abilities and require significant human resources. This paper proposes a sensing system that automatically extracts and fuses sensory features such as body motion features, facial expressions, and gaze features, further assessing the children behaviours by mapping them to therapist-specified behavioural classes. Experimental results show that the developed system has a capability of interpreting characteristic data of children with ASD, thus has the potential to increase the autonomy of robots under the supervision of a therapist and enhance the quality of the digital description of children with ASD. The research outcomes pave the way to a feasible machine-assisted system for their behaviour assessment. IEEE
  •  
29.
  • Cao, Mingwei, et al. (författare)
  • FAPP : Extremely Fast Approach to Boosting Image Matching Precision
  • 2024
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 24:4, s. 4907-4919
  • Tidskriftsartikel (refereegranskat)abstract
    • Feature matching is a critical problem in the field of computer vision, which serves as the foundation for many high-level computer vision applications. This article aims to improve the accuracy of feature matching by eliminating mismatches in putative matches. To achieve this goal, we propose an extremely fast approach to boosting image matching precision (FAPP). The key idea behind FAPP is that correct feature matches have similar Euclidean distances, and the sine values of the angles between correct feature matches and the horizontal axis are also similar. Consequently, putative matches can be represented as 2-D coordinate points (sine value, Euclidean distance), which makes correct and incorrect feature matches have different degrees of clustering. The coordinate points are, furthermore, divided into grid spaces so that the coordinate points are distributed in different grid areas. Through adaptive parameter estimation, we determine a threshold for the number of correct feature matches within each grid, thereby eliminating false feature matches. In addition, to validate the effectiveness of FAPP, we conducted experiments on two public datasets and compared the results with several existing classical methods. The experimental outcomes demonstrate the superior performance of FAPP over the existing classical methods. Furthermore, the method has been applied to 3-D reconstruction with good results. Source code: https://github.com/caomw/fapp.
  •  
30.
  • Cao, Mingwei, et al. (författare)
  • MLV : Robust Image Matching via Multilayer Verification
  • 2024
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 24:9, s. 14454-14470
  • Tidskriftsartikel (refereegranskat)abstract
    • Image matching is one of the hottest research topics in the field of computer vision, and it aims to compute the correct feature correspondences between images; however, under the influence of illumination changes and scale changes, relying only on the similarity between feature descriptors as the basis for judging feature matching tends to generate more false feature correspondences. To solve the above problems, in this article, we systematically analyze various factors that lead to false feature correspondences, design corresponding solutions for these various factors, and then propose a multilayer verification (MLV) image-matching method. First, eliminating the potential mismatches caused by brute force matching; second, eliminating the mismatches caused by the ambiguity of descriptors; and third, eliminating the feature matches that do not satisfy geometric constraints. Finally, we test the proposed MLV method on several open-source datasets and make a comprehensive comparison with the classical methods. Experimental results show that the MLV method not only can compute more true feature correspondences but also has a low computational cost. In addition, we applied the MLV method to sparse point cloud reconstruction to demonstrate its practical application value. Source code: https://github.com/caomw/mlv.
  •  
31.
  • Carlsson, Håkan, et al. (författare)
  • Quantifying the Uncertainty of the Relative Geometry in Inertial Sensors Arrays
  • 2021
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 21:17, s. 19362-19373
  • Tidskriftsartikel (refereegranskat)abstract
    • We present an algorithm to estimate and quantify the uncertainty of the accelerometers' relative geometry in an inertial sensor array. We formulate the calibration problem as a Bayesian estimation problem and propose an algorithm that samples the accelerometer positions' posterior distribution using Markov chain Monte Carlo. By identifying linear substructures of the measurement model, the unknown linear motion parameters are analytically marginalized, and the remaining non-linear motion parameters are numerically marginalized. The numerical marginalization occurs in a low dimensional space where the gyroscopes give information about the motion. This combination of information from gyroscopes and analytical marginalization allows the user to make no assumptions of the motion before the calibration. It thus enables the user to estimate the accelerometer positions' relative geometry by simply exposing the array to arbitrary twisting motion. We show that the calibration algorithm gives good results on both simulated and experimental data, despite sampling a high dimensional space.
  •  
32.
  • Carlsson, Håkan, et al. (författare)
  • Self-Calibration of Inertial Sensor Arrays
  • 2021
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 21:6, s. 8451-8463
  • Tidskriftsartikel (refereegranskat)abstract
    • A maximum likelihood estimator is presented for self-calibrating both accelerometers and gyroscopes in an inertial sensor array, including scale factors, misalignments, biases, and sensor positions. By simultaneous estimation of the calibration parameters and the motion dynamics of the array, external equipment is not required for the method. A computational efficient iterative optimization method is proposed where the calibration problem is divided into smaller subproblems. Further, an identifiability analysis of the calibration problem is presented. The analysis shows that it is sufficient to know the magnitude of the local gravity vector and the average scale factor gain of the gyroscopes, and that the array is exposed to two types of motions for the calibration problem to be well defined. The proposed estimator is evaluated by real-world experiments and by Monte Carlo simulations. The results show that the parameters can be consistently estimated and that the calibration significantly improves the accuracy of the motion estimation. This enables on-the-fly calibration of small inertial sensors arrays by simply twisting them by hand.
  •  
33.
  • Chen, Guang, et al. (författare)
  • A Novel Visible Light Positioning System With Event-Based Neuromorphic Vision Sensor
  • 2020
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 20:17, s. 10211-10219
  • Tidskriftsartikel (refereegranskat)abstract
    • With the advanced development of image processing technology, visible light positioning (VLP) system based on image sensors has attracted more and more attention. However, as a commonly used light receiver, traditional CMOS camera has limited dynamic range and high latency, which is susceptible to various lighting and environmental factors. Moreover, high computational cost from image processing is unavoidable for most of visible light positioning systems. In our work, a novel VLP system using an event-based neuromorphic vision sensor (event camera) as the light receiver is proposed. Due to the low latency and microsecond-level temporal resolution of the event camera, our VLP system is able to identify multiple high-frequency flickering LEDs in asynchronous events simultaneously leaving out the need for data association and traditional image processing methods. A multi-LED fusion method is applied and a high positioning accuracy of 3cm is achieved when the height between LEDs and the event camera is within 1m.
  •  
34.
  • Chen, Guang, et al. (författare)
  • EDDD : Event-Based Drowsiness Driving Detection Through Facial Motion Analysis With Neuromorphic Vision Sensor
  • 2020
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 20:11, s. 6170-6181
  • Tidskriftsartikel (refereegranskat)abstract
    • Drowsiness driving is a principal factor of many fatal traffic accidents. This paper presents the first event-based drowsiness driving detection (EDDD) system by using the recently developed neuromorphic vision sensor. Compared with traditional frame-based cameras, neuromorphic vision sensors, such as Dynamic Vision Sensors (DVS), have a high dynamic range and do not acquire full images at a fixed frame rate but rather have independent pixels that output intensity changes (called events) asynchronously at the time they occur. Since events are generated by moving edges in the scene, DVS is considered as an efficient and effective detector for the drowsiness driving-related motions. Based on this unique output, this work first proposes a highly efficient method to recognize and localize the driver's eyes and mouth motions from event streams. We further design and extract event-based drowsiness-related features directly from the event streams caused by eyes and mouths motions, then the EDDD model is established based on these features. Additionally, we provide the EDDD dataset, the first public dataset dedicated to event-based drowsiness driving detection. The EDDD dataset has 260 recordings in daytime and evening with several challenging scenes such as subjects wearing glasses/sunglasses. Experiments are conducted based on this dataset and demonstrate the high efficiency and accuracy of our method under different illumination conditions. As the first investigation of the usage of DVS in drowsiness driving detection applications, we hope that this work will inspire more event-based drowsiness driving detection research.
  •  
35.
  • Cheng, Peng, et al. (författare)
  • Stator-free RPM Sensor Using Accelerometers - A Statistical Performance Simulation by Monte Carlo Method
  • 2011
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 11:12, s. 3368-3376
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents an statistical performance simulation for rigid-body revolutions per minute (RPM) measurement based on two uni-axial accelerometers mounted on rotor. In comparison with other existing sensing methods that are based on two coupled parts, namely stator and rotor and which include conventional electro-magnetic RPM sensors and photo-electric RPM sensors, this new stator-free inertial sensing principle has the advantage of high bandwidth at low RPM, true contact-free sensing and flexible installation. The paper first focuses on the description of the operating principle and the common mode rejection (CMR) method of the stator-free RPM sensor, and then its error model is developed and the error sources are statistically simulated based on Monte Carlo method. The simulation result presents a most interesting property of this sensor, that is, it gives lower precision at lower RPM and higher precision at higher RPM. The conclusion summarizes the modeling analysis result and motivates potential application for this new RPM sensing method.
  •  
36.
  • Cheng, Peng, et al. (författare)
  • Torque Sensor Based on Differential Air Pressure Using Volumetric Strain
  • 2017
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 17:11, s. 3269-3277
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper proposes a torque sensor based on the differential air pressure measurement method using the volumetric strain of a mechanical sensing structure. A model of the measurement system based on the differential air pressure from the volumetric strain of the mechanical sensing structure is proposed and theoretically discussed. The error sources are identified and an error propagation model is presented for the proposed torque measurement method. Considering these error sources, a prototype torque sensor is presented as a case study for the method verification. Both the mechanical and readout electronics designs are discussed and analyzed. The mechanical sensitivity, resolution, and maximum stresses are analyzed using finite-element modeling. Based on the results from the simulation, a prototype torque sensor is manufactured and experimentally verified using a readout electronics design. For verification, the sensor prototype is measured under static torque to have a sensitivity of 0.04272V/N. m and a range of +/- 117N . m. Compared with the nominal mechanical sensitivity result from the FEM simulation, this measured sensitivity has a difference less than 6%. The noise analysis of the designed readout electronics shows that the resolution of 0.006% can be achieved with this design. Furthermore, hysteresis analysis shows an error of 0.012% of full scale. From these results, it is also shown that the actual performance of the sensor is mainly limited by the differential pressure sensor and the readout electronics design and is not by the mechanical design of the sensor.
  •  
37.
  • Choudhary, Anurag, et al. (författare)
  • Infrared Thermography-Based Fault Diagnosis of Induction Motor Bearings Using Machine Learning
  • 2021
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748. ; 21:2, s. 1727-1734
  • Tidskriftsartikel (refereegranskat)abstract
    • Bearing is one of the most crucial parts in induction motor (IM) as a result there is a constant call for effective diagnosis of bearing faults for reliable operation. Infrared thermography (IRT) is appreciably used as a non-destructive and non-contact method to detect the bearing defects in a rotary machine. However, its performance is limited by insignificant information and string noise present in the infrared thermal image. To address this issue, an emergent two dimensional discrete wavelet transform (2D-DWT) based IRT method has been proposed in this article for diagnosing the different bearing faults in IM, namely, inner and outer race defects, and lack of lubrication. The dimensionality of the extracted features was reduced using principal component analysis (PCA) and thereafter the selected features were ranked in the order of most relevant features using the Mahalanobis distance (MD) method to achieve the optimal feature set. Finally these selected features have been passed to the complex decision tree (CDT), linear discriminant analysis (LDA) and support vector machine (SVM) for fault classification and performance evaluation. The classification results reveal that the SVM outperformed CDT and LDA. The proposed strategy can be used for self-adaptive recognition of bearing faults in IM which helps to avoid the unplanned and unwanted system shutdowns due to the bearing failure. © 2001-2012 IEEE.
  •  
38.
  • Choudhary, Vipin, et al. (författare)
  • A Non-destructive Testing Method in Industrial Processes to Determine the Complex Refractive Index Using Ultra-Wide Band Radio
  • 2022
  • Ingår i: IEEE Sensors Journal. - : IEEE. - 1530-437X .- 1558-1748 .- 2379-9153. ; 22:8, s. 7752-7762
  • Tidskriftsartikel (refereegranskat)abstract
    • An ultra-wide band measurement method for determining the complex refractive index of large-volume objects is presented. The method is intended for industrial non-destructive testing. It uses a frequency-domain technique in which transmitted radio pulses are analyzed and the effects of near field and coupling on the determined refractive index are compensated. Measurements were performed in an industrial setup with electromagnetic sensors buried in the object. The results are presented for woodchips as an object. The refractive index was experimentally determined in the frequency range 0.5-3.0 GHz. Additionally, we designed and manufactured planar quasi-differential elliptical-antennas as electromagnetic sensors. The results from the industrial measurement setup were compared with the results of the laboratory setup, in which the sensors were placed outside the test box and near field and coupling effects could be neglected. The complex refractive index determined for the two setups was in good agreement, which corroborates the proposed method for compensating for coupling and near-field effects. The complex refractive index of woodchips changes with the moisture content. It is experimental verified using the industrial setup that the moisture content can be determined with a 2 percent error.
  •  
39.
  • Concina, Isabella, et al. (författare)
  • Electronic noses as flexible tools to assess food quality and safety : Should we trust them?
  • 2012
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:11, s. 3232-3237
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents three different applications of an electronic nose (EN) based on a metal oxide sensor array, in order to illustrate the broad spectrum of potential uses of the technique in food quality control. The following scenarios are considered: 1) the screening of a typical error that may occur during the processing of tomato pulp, which leads to sensory damage of the product; 2) the detection of microbial contamination by Alicyclobacillus spp. (ACB) affecting soft drinks; and 3) the proof of evidence of extra virgin olive oil fraudulently adulterated with hazelnut oil. In each case, the EN is able to identify the spoiled product by means of the alterations in the pattern of volatile compounds, reconstructed by principal component analysis of the sensor responses.
  •  
40.
  •  
41.
  • Damiati, Samar, et al. (författare)
  • Flex Printed Circuit Board Implemented Grapene-Based DNA Sensor for Detection of SARS-CoV-2
  • 2021
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 21:12, s. 13060-13067
  • Tidskriftsartikel (refereegranskat)abstract
    • Since the COVID-19 outbreak was declared a pandemic by the World Health Organization (WHO) in March 2020, ongoing efforts have been made to develop sensitive diagnostic platforms. Detection of viral RNA provides the highest sensitivity and specificity for detection of early and asymptomatic infections. Thus, this work aimed at developing a label-free genosensor composed of graphene as a working electrode that could be embedded into a flex printed circuit board (FPCB) for the rapid, sensitive, amplification-free and label-free detection of SARS-CoV-2. To facilitate liquid handling and ease of use, the developed biosensor was embedded with a user-friendly reservoir chamber. As a proof-of-concept, detection of a synthetic DNA strand matching the sequence of ORF1ab was performed as a two-step strategy involving the immobilization of a biotinylated complementary sequence on a streptavidin-modified surface, followed by hybridization with the target sequence recorded by the differential pulse voltammetric (DPV) technique in the presence of a ferro/ferricyanide redox couple. The effective design of the sensing platform improved its selectivity and sensitivity and allowed DNA quantification ranging from 100 fg/mL to 1 mu g/mL. Combining the electrochemical technique with FPCB enabled rapid detection of the target sequence using a small volume of the sample (5-20 mu L). We achieved a limit-of-detection of 100 fg/mL, whereas the predicted value was similar to 33 fg/mL, equivalent to approximately 5 x 10(5) copies/mL and comparable to sensitivities provided by isothermal nucleic acid amplification tests. We believe that the developed approach proves the ability of an FPCB-implemented DNA sensor to act as a potentially simpler and more affordable diagnostic assay for viral infections in Point-Of-Care (POC) applications.
  •  
42.
  • Davide, F., et al. (författare)
  • Chaotic chemical sensing
  • 2002
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 2:6, s. 656-662
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, we have examined the behavior of a chaotic circuit where one of the components has been replaced by a chemical sensor. The response of the sensor is manifested as a change in the attractor of the circuit. Furthermore, with a proper operating point, a small response of the sensor causes a change in the attractor of the circuit within a time much shorter than the normally defined response time of the sensor. This technique unites sensors and data processing as one combined unit in a unique fashion. © 2002 IEEE.
  •  
43.
  • Enlund, Johannes, et al. (författare)
  • FBAR sensor array for in liquid operation
  • 2010
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 10:12, s. 1903-1904
  • Tidskriftsartikel (refereegranskat)abstract
    • This letter discusses the design of thickness shear mode thin-film bulk acoustic resonator (FBAR) sensor array for in liquid operation with respect to minimizing the observed Q-degradation and crosstalk.
  •  
44.
  •  
45.
  • Farag, Hossam, et al. (författare)
  • A Delay-Bounded MAC Protocol for Mission- and Time-Critical Applications in Industrial Wireless Sensor Networks
  • 2018
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 18:6, s. 2607-2616
  • Tidskriftsartikel (refereegranskat)abstract
    • Industrial Wireless Sensor Networks (IWSNs) designedfor mission- and time-critical applications require timelyand deterministic data delivery within stringent deadline bounds.Exceeding delay limits for such applications can lead to system malfunction or ultimately dangerous situations that can threaten human safety. In this paper, we propose SS-MAC, an efficient slot stealing MAC protocol to guarantee predictable and timely channel access for time-critical data in IWSNs. In the proposed SS-MAC, aperiodic time-critical traffic opportunistically steals time slots assigned to periodic non-critical traffic. Additionally, a dynamic deadline-based scheduling is introduced to provide guaranteed channel access in emergency and event-based situations where multiple sensor nodes are triggered simultaneously to transmit time-critical data to the controller. The proposed protocol is evaluated mathematically to provide the worst-case delay bound for the time-critical traffic. Performance comparisons are carried out between the proposed SS-MAC and WirelessHARTstandard and they show that, for the time-critical traffic, theproposed SS-MAC can achieve, at least, a reduction of almost 30% in the worst-case delay with a significant channel utilization efficiency.
  •  
46.
  • Farag, Hossam, et al. (författare)
  • Priority-Aware Wireless Fieldbus Protocol for Mixed-Criticality Industrial Wireless Sensor Networks
  • 2019
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 19:7, s. 2767-2780
  • Tidskriftsartikel (refereegranskat)abstract
    • Industrial wireless sensor networks are becoming popular for critical monitoring and control applications in industrial automation systems. For such type of applications, providing reliable real-time performance regarding data delivery is considered as a fundamental challenge. The problem becomes more prominent with mixed-criticality systems, where different data flow with different levels of criticality (importance) coexist and characterized by different requirements regarding delay and reliability. In this paper, we propose a wireless fieldbus protocol to enable real-time communication and service differentiation for cluster-based mixed-criticality networks. A process monitoring scenario of plastic extrusion is used to define the protocol requirements and elaborate the working principle of the proposed work. In our proposed protocol, each data flow is scheduled for channel access based on its criticality level using a distributed prioritized medium access mechanism that ensures a guaranteed channel access for the most critical traffic over other traffic types. The performance of the proposed protocol is analyzed analytically using a discrete-time Markov chain model to evaluate the performance in terms of delay and throughput. Moreover, the extensive simulations are conducted to prove the analytical claims and different performance assessments are provided, which also demonstrate the effectiveness of the proposed approach compared with the related existing work.
  •  
47.
  • Feng, Yi, et al. (författare)
  • Flexible UHF resistive humidity sensors based on carbon nanotubes
  • 2012
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 12:9, s. 2844-2850
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents the investigation of the resistive humidity-sensing properties of multi-walled carbon nanotubes (MWCNTs). MWCNTs functionalized by acid treatment (f-MWCNTs) exhibit rather high sensitivity in resistance toward humidity, owing to the presence of carboxylic groups on the nanotube surface. By integrating the f-MWCNTs resistor into a wireless sensor platform, flexible humidity sensors for ultra-high frequency applications are investigated. The operating frequency range of the sensor is dramatically increased from 600 MHz to 2 GHz by adjusting the resistor-electrodes' configuration. This enhancement is predominately attributed to the variation in parasitic capacitance between the resistor-electrodes.
  •  
48.
  • Feng, Yi, et al. (författare)
  • Low Cost Printed Chipless RFID Humidity Sensor Tag for Intelligent Packaging
  • 2015
  • Ingår i: IEEE Sensors Journal. - 1530-437X .- 1558-1748. ; 15:6, s. 3201-3208
  • Tidskriftsartikel (refereegranskat)abstract
    • This paper presents a fully-printed chipless radio frequency identification sensor tag for short-range item identification and humidity monitoring applications. The tag consists of two planar inductor-capacitor resonators operating wirelessly through inductive coupling. One resonator is used to encode ID data based on frequency spectrum signature, and another one works as a humidity sensor, utilizing a paper substrate as a sensing material. The sensing performances of three paper substrates, including commercial packaging paper, are investigated. The use of paper provides excellent sensitivity and reasonable response time to humidity. The cheap and robust packaging paper, particularly, exhibits the largest sensitivity over the relative humidity range from 20% to 70%, which offers the possibility of directly printing the sensor tag on traditional packages to make the package intelligent at ultralow cost.
  •  
49.
  • Fernández Schrunder, Alejandro, 1993-, et al. (författare)
  • A Real-Time Muscle Fatigue Detection System Based on Multi-Frequency EIM and sEMG for Effective NMES
  • 2024
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; , s. 1-1
  • Tidskriftsartikel (refereegranskat)abstract
    • Neuromuscular electrical stimulation (NMES) is a self-directed home based therapeutic tool in early rehabilitation for musculoskeletal (MSK) conditions. However, the effectiveness of traditional NMES is fundamentally constrained by muscle fatigue. To address this limitation, this work proposes a detection system, which simultaneously records multifrequency electrical impedance myography (EIM) and surface electromyography(sEMG) in real time for time-frequency analysis of muscle activation, contraction, and fatigue. To demonstrate the ability to monitor these muscle physiological states, two experiments involving weightless and weighted dynamic contractions of the biceps brachii muscle were performed. Results from these experiments show synchronous changes in sEMG and EIM spectra during contractions, and clear trends in sEMG’s mean power frequency (MPF) and EIM spectra with fatigue progression. Additionally, the configurable 4-channel NMES has been electrically evaluated for clinical use, demonstrating the feasibility of the proposed system for closed-loop stimulation. This work showcases the potential of sEMG and multi-frequency EIM to enhance the effectiveness of NMES for MSK conditions by capturing the behavior of distinct mechanisms of muscle fatigue.
  •  
50.
  • Fu, Hongyan, et al. (författare)
  • Transversal-Load Sensor by Using Local Pressure on a Chirped Fiber Bragg Grating
  • 2010
  • Ingår i: IEEE Sensors Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 1530-437X .- 1558-1748. ; 10:6, s. 1140-1141
  • Tidskriftsartikel (refereegranskat)abstract
    • A transversal-load sensor based on the local pressure-induced refractive index change in a chirped fiber Bragg grating (CFBG) is proposed. The local pressure induced refractive index change in the touch point can generate a main transmission peak and several subpeaks on the long wavelength side of the reflection band of the CFBG. The difference of the wavelength shifts for the main transmission peak and the first subpeak is used to measure transversal-load with temperature compensation capability.
  •  
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