By Topic

Sensors Journal, IEEE

Early Access Articles

Early Access articles are new content made available in advance of the final electronic or print versions and result from IEEE's Preprint or Rapid Post processes. Preprint articles are peer-reviewed but not fully edited. Rapid Post articles are peer-reviewed and edited but not paginated. Both these types of Early Access articles are fully citable from the moment they appear in IEEE Xplore.

Filter Results

Displaying Results 1 - 25 of 157
  • A Resistivity Model for Ultra-Thin Films and Sensors

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3340 KB)  

    Gas sensors have been demonstrated based on conductivity changes in ultra-thin films. These sensors operate in a regime where three different physical phenomena determine the total resistivity of the film; quantum mechanical coupling between metallic islands, bulk material conductivity of the islands, and network resistivity. We present a lumped parameter model that simulates thin film growth and calculates the total film resistance during the growth process accounting for these three phenomena. The model contains four free parameters and yields good agreement with experimental data presented for palladium, titanium, and gold. The primary benefit of this model is that it shows the relative contribution of each source of conductivity during the growth process providing insight into the operation of ultra-thin films as gas sensors. We then model an ultra-thin film palladium based hydrogen sensor and show that the sensing mechanism is primarily due to variations in quantum tunneling. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Temperature Sensor Based on Quantum Dots Solution Encapsulated in Photonic Crystal Fiber

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (979 KB)  

    A luminescence temperature sensor was proposed based on quantum dots (QDs) aqueous solution encapsulated in a photonic crystal fiber (PCF) and sandwich structure by fusion splicing two multimode fibers (MMF) end-to-end. The relationships of the luminescent peak, intensity and the Full Width at Half Maximum (FWHM) of the luminescent emission band with the temperature are investigated. A self-referenced method is used to optimize the relationship between intensity and temperature. The experimental results indicate that the sensitivities are 130.9pm/???, 67pm/???and -0.008/??? respectively with favorable repeatability for the luminescent peak, the FWHM and the self-referenced intensity in the temperature range from -10??? to 120???. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Chemically modified carbon paste electrode for Cu2+ ion determination

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (999 KB)  

    A novel carbon paste electrode (CPE) was fabricated using 2-methoxy-6-(((3-(trimethoxysilyl) propyl) imino) methyl) phenol chemically bonded to multiwalled carbon nanotubes (MMSPIMP–MWCNT) followed by intermixing with CuO nanoparticles, sodium tetraphenylborate (NaTPB), graphite powder and Nujol oil. The MMSPIMP–MWCNT was characterized by Fourier Transform Infrared spectroscopy (FT-IR) and other appropriate techniques. The influences of variables including the amounts of sodium tetraphenylborate (NaTPB), modified multiwalled carbon nanotubes (MWCNT), CuO nanoparticles, graphite powder and Nujol oil on the electrode response were studied and optimized. Optimum composition of carbon paste was found to be a mixture of 120 mg Nujol with graphite powder: NaTPB: carrier with the mass (mg) ratio of 150:9:60. Thus the applied recipe for the construction of CPE, significantly enhanced its selectivity and sensitivity to Cu2+ ions over a wide concentration range of 4.09×10-8-1.0×10-2 mol L−1 with detection limit of 1.6×10-8 mol L−1 and a Nernstian slope of 29.56 ± 0.56 mV per decade of Cu2+ concentration. The electrode response is independent of pH in the range of 3.5−5.5 with response time lower than 20 s. The potentiometric selectivity coefficients of the proposed Cu2+ ion - CPE show its moderate selectivity for Cu2+ ion towards other metal ions. MMSPIMP-MWCNT was found to be a suitable neutral carrier for the construction of a carbon paste electrode for the determination of Cu2+ ion in solution. Finally, from practical point of view, this electrode was successfully applied for the determination of Cu2+ ions content in real water sample. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Suspended Thermopile for Microwave Power Sensors Based on Bulk MEMS and GaAs MMIC Technology

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (293 KB)  

    In this letter, the effects of the suspended thermopile on the microwave and sensing performances of 0.01-30 GHz thermoelectric microwave power sensors are researched by experiments, in order to obtain the reasonable back-cavity dimension. The back-cavity underneath the thermopile is used to depress thermal losses of the power sensors and is fabricated using the bulk MEMS process. Three thermoelectric power sensors with different suspension lengths of the thermopile are accomplished with the GaAs MMIC technology. The three power sensors show good microwave matching impedance, with measured reflection losses of less than -21 dB up to 30 GHz. The good linearity between the input power and the output thermovoltages is obtained. When the suspension length of the thermopile is 20, 50 and 80 μm, the average sensitivity of these power sensors is 186.9, 238.9 and 286.0 μV/mW at 30 GHz, respectively. In addition, the relationships of the sensitivity with the microwave power and frequency are quantified under different suspension lengths of the thermopile. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • SmartPDR: Smartphone-Based Pedestrian Dead Reckoning for Indoor Localization

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6029 KB)  

    Indoor pedestrian tracking extends location-based services to indoor environments where GPS signal is rarely detected. Typical indoor localization method is Wi-Fi-based positioning system, which is practical showing accuracy and extending coverage. However, it involves significant costs of installing and managing wireless access points. A practical indoor pedestrian tracking approach should consider the absence of any infrastructure or pretrained database. In this paper, we present a smartphone-based pedestrian dead reckoning, SmartPDR, which tracks pedestrian through typical dead reckoning approach using data from inertial sensors embedded in smartphones. SmartPDR does not require any complex and expensive additional device or infrastructure that most existing pedestrian tracking systems rely on. The proposed system was implemented on off-theshelf smartphones and the performance was evaluated in several buildings. Despite inherent localization errors from low-cost noisy sensors and complicated human movements, SmartPDR successfully tracks indoor user’s location, which is confirmed from the experimental results with reasonable location accuracy. Indoor pedestrian tracking system using smartphone inertial sensors can be a promising methodology validating its practical usage through real deployment. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Encryption Scheme Using Chaotic Map and Genetic Operations for Wireless Sensor Networks

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (643 KB)  

    Over the past decade, the application domain of wireless sensor networks has expanded steadily, ranging from environmental management to industry control, from structural health monitoring to strategic surveillance. With the proliferation of sensor networks at home, work place, and beyond, securing data in the network has become a challenge. A number of security mechanisms have been proposed for sensor networks to provide data confidentiality: AES, KATAN, LED, and TWINE. However, these schemes have drawbacks, including security vulnerabilities, need for hardware based implementation, and higher computational complexity. To address these limitations, we propose a lightweight block cipher based on chaotic map and genetic operations. The proposed cryptographic scheme employs elliptic curve points to verify the communicating nodes and as one of the chaotic map parameters to generate the pseudorandom bit sequence. This sequence is used in XOR, mutation and crossover operations in order to encrypt the data blocks. The experimental results based on Mica2 sensor mote show that the proposed encryption scheme is nine times faster than the LED protocol and two times faster than the TWINE protocol. We have also performed a number of statistical tests and cryptanalytic attacks to evaluate the security strength of the algorithm and found the cipher provably secure. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fabrication and Characterization of Long Period Gratings in Hollow Core Fibers by Electric Arc Discharge

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (693 KB)  

    Recently the fabrication of Long Period Gratings (LPGs) in hollow-core air-silica photonic bandgap fibers by means of pressure assisted Electrode Arc Discharge (EAD) technique have been presented.. The EAD procedure properly combined with air pressure inside fiber holes enables the localized modification of hole size and shape in both core and cladding region avoiding holes collapsing. LPGs are fabricated with a step-by-step approach by periodically repeated EAD treatment. In this paper, the role of pressure inside the fiber holes as well as the effect of the grating pitch on the transmitted spectra have been experimentally investigated in order to achieve design criteria of novel hollow core devices. An appropriate perturbation of fiber structure (core and/or cladding) may change the field profile of the fiber modes and cause light coupling from the fundamental mode to higher order modes. Here, the experimental demonstration of LPG prototypes with different features exhibiting attenuation bands with depth up to 12 dB are reported. Finally, the resonant wavelength dependence on local temperature and strain changes are experimentally investigated. We believe that the fabrication of LPGs based devices in hollow core optical fibers enable new functionalities hitherto not possible. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Electric-field assisted desorption of water molecules in DNA functionalized CNT network

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (353 KB)  

    This paper introduces the concept of electric field assisted desorption (EAD) of water molecules from the surface of DNA functionalized carbon nanotube (DFC) resistive network when a bias voltage VDS is applied across it. EAD at a given VDS is measured in terms of the characteristic life-time of desorption τ. The bias voltage produces an electric field E that aligns the molecular dipoles of water parallel to E. Mutually aligned neighboring dipole moments of water maximize the potential energy and drives them into a non-equilibrium state. The molecular dipoles return to the minimum potential energy state when water molecules escape from the surface of DFC. We find an exponential decrease in τ for VDS < Vcr which is attributed to EAD. Beyond Vcr we observe a linear increase in τ which is due to charge entrapment within ultrathin layer of water sandwiched between dielectric layers of DNA and air that prevents fast desorption of water molecules. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New Object Detection, Tracking and Recognition Approaches for Video Surveillance over Camera Network

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (16549 KB)  

    Object detection and tracking are two fundamental tasks in multi-camera surveillances. This paper proposes a framework for achieving these tasks in a non-overlapping multiple camera network. A new object detection algorithm using mean shift (MS) segmentation is introduced and occluded objects are further separated with the help of depth information derived from stereo vision. The detected objects are then tracked by a new object tracking algorithm using a novel Bayesian Kalman filter (BKF) with simplified Gaussian mixture (BKF-SGM). It employs a GM representation of the state and noise densities and a novel direct density simplifying algorithm for avoiding the exponential complexity growth of conventional KFs using GM. When coupled with an improved MS tracker, a new BKF-SGM with improved MS (BKF-SGM-IMS) algorithm with more robust tracking performance is obtained. Furthermore, a non-training-based object recognition algorithm is employed to support object tracking over non-overlapping network. Experimental results show that: 1) the proposed object detection algorithm yields improved segmentation results over conventional object detection methods, 2) the proposed tracking algorithm can successfully handle complex scenarios with good performance and low arithmetic complexity. Moreover, the performance of both non-training/ training-based object recognition algorithms can be improved by using our detection and tracking results as input. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Side-Hole Plastic Optical Fiber for Testing Liquid’s Refractive Index

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (455 KB)  

    A multimode plastic optical fiber with a side-hole fabricated by precision mechanical drilling technology is presented for refractive index (RI) sensing. A higher sensitivity of 1862.1 μW/RIU, when center wavelength of optical source is 652 nm and launched power is 1 mW, is obtained in a larger hole diameter of 350 μm, indicating that larger hole diameter can increase the sensitivity of the sensor. Ray-optics method and FDTD method are both utilized to theoretically evaluate the characteristics of the structure for refractive index testing, which is well in agreement with experimental results. Energy field distribution is analyzed to explain the sensing mechanism of the structure, which demonstrates that the divergent effect of the side-hole like a negative lens is the key to sensing. Due to the advantages of relative easily fabricated, low-cost and capable of continuous measurement, this side-hole based fiber sensing structure is attractive for RI monitoring in chemical, biological, and biochemical sensing region. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Crowd Escape Behavior Detection and Localization Based on Divergent Centers

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (750 KB)  

    In this paper, we propose a novel framework for anomalous crowd behavior detection and localization by introducing divergent centers in intelligent video surveillance systems. In this work, the scheme proposed can deal with this problem by modeling the crowd motion obtained from the optical flow. The obtained magnitude, position and direction are used to construct the motion model. The method of the weighted velocity is applied to calculate the motion velocity. People usually instinctively escape from a place where abnormal or dangerous events occur. Based on this inference, a novel algorithm of detecting divergent centers is proposed: Divergent centers indicate possible places where abnormal events occur. The proposed algorithm of detect divergent centers can identify more than one divergent center by analysis the intersections of vectors, and this algorithm consist of the distance segmentation method and the Nearest Neighbor Search. The performance of our method is validated in a number of experiments on public datasets. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Tube Glass Waveguides Modified With Gold Nanoparticles for Application as A Simple Chemical and Biological Sensor

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (589 KB)  

    A low-cost simple and stable optical chemical and biological sensor was prepared by using a U-shaped glass tube whose 200-μm-thick wall coated with a colored layer serves as a sensitive waveguide. Light from a LED is launched into the glass wall of the tube from an endface and emits from the other endface to be detected with a silicon photodetector. The refractive-index (RI) sensitivity of the sensor is mainly attributed to the clad-RI-induced enhancement of evanescent field that results in the increased absorption of the colored layer. The sensor’s sensitivity can be effectively improved by HF etching of the bent portion of the U-shaped tube before deposition of the colored layer. The gold-nanoparticle (GNP) monolayer was used as the colored layer in this work, and the GNP self-assembly process that took more than 12 hours was in situ monitored with the sensor. The resulting sensor can easily detect a small change of 1 wt% in sucrose concentration, and is also applicable for real-time detection of bimolecular adsorption and immunoreaction. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Optical Fiber Fabry-Perot Interferometer Sensor for Simultaneous Measurement of Relative Humidity and Temperature

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1542 KB)  

    A simultaneous relative humidity (RH) and temperature sensor based on an optical fiber Fabry-Perot interferometer (FPI) is proposed and experimentally demonstrated. This sensor is constructed by splicing a short length of photonic crystal fiber (PCF) to single mode fiber (SMF) and coating an ultrathin polyvinyl alcohol (PVA) film to the PCF's cleaved surface. The total length of this sensing head is only about 110µm and the compact size means it can be used flexibly in limited space and harsh environments. Experimental results demonstrate that this sensor can simultaneously measure the ambient RH and temperature by demodulating the power change and wavelength shift of reflection spectrum. Consequently, the advantages of compact size, low cost, high flexibility and stability, fast response, and simultaneous RH and temperature measurement ability means the proposed sensor has an extensive range of potential applications. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fabrication of a Glow Discharge Plasma-based Ionization GasSensor using Multi-Walled Carbon Nanotubes for Specific Detection of Hydrogenat Parts per Billion Levels

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (859 KB)  

    A new glow discharge plasma-based sensor is fabricated for specific detection of hydrogen (H2) at parts per billion (ppb) levels based on gas ionization process under vacuum condition (~0.01 torr). The system setup consists of a twoelectrode system including graphite electrode (diameter: 6.5 mm), modified with arc-synthesized carbon nanostructures as anode and an aluminum disk with 2.4 mm diameter as cathode with inter-electrodes distance of 700±10 μm inside a glass chamber. For H2 detection, ionization current is considered as detection system, during applying an 853-V direct current potential as a fingerprint breakdown voltage for H2 ionization to the electrodes. According to the results, the sensor is linear ranging from 40 to 86 ppb. The relative standard deviation of nine replicate analyses during introduction of ~60 ppb of H2 is 2.57 %. Also, the detection limit is evaluated to ~3.3 ppb. No interfering effect is observed when introduction of at least 1000- fold excess (mass/mass) of foreign species such as Ar, He, CO2, CO, C2H2, O2, acetone, and CH3OH to ~60 ppb of H2 standard solution. Reliability of the sensor is also evaluated via determination of H2 in two industrial gas samples. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Ultrasonic Sensor Triangulation for accurate 3D Relative Positioning of Humanoid Robot Feet

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (777 KB)  

    A simple measurement system with a set of six ultrasonic piezoelectric transducers is presented for direct 3D positioning of humanoid robot limbs. A configuration with three emitters and three receivers leads to millimetric estimation of the distances. Millimetric resolution achievement over 70 cm range is aimed with high angular tolerance in order to mount the sensor on a humanoid robot. Sampling frequency up to 60 Hz is obtained. The sensor is then used to estimate relative positions and orientations in the space of each foot of the robot with regard to the pelvis. The principle and experimental performances of the sensor are presented in the first part with uncertainty estimations and discussions. In the second phase, the sensor has been set up on the ROBIAN humanoid robot to illustrate an application case and test the performances. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Selective detection of Hg (II) over Cd(II) and Pb(II) ions by DNA functionalized CNT network

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (713 KB)  

    This work describes the selective detection of Hg(II) ions over Cd(II) and Pb(II) ions by DNA functionalized carbon nanotube (DFC) resistive network. The nucleobases, especially adenine and thymine, which are bound to the nanotubes through π—π stacking interactions, have strong affinities for Hg(II) ions and bind to the Hg(II) ions at suitable ligand sites forming a stable chelate complex. The coordinate ligand-Hg(II) bond possesses higher covalent character than either the ligand-Cd(II) or the ligand-Pb(II) bond. The higher the covalent character of the coordinate bonds in the chelate complex formed on the DFC network more is the e-scattering at the metal binding sites and thus greater is the reduction in the conductance of the DFC network. The amount of covalent character of the metal-ligand bond is measured by the stability factor of the complex. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Abnormal Scene Change Detection from a Moving Camera Using Bags of Patches and Spider-Web Map

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (983 KB)  

    This paper proposes a novel surveillance system for detecting exceptional scene changes as abnormal events with a mobile camera mounted on a robot. In contrast to abnormal event analysis using fixed cameras, three key problems should be tackled in this system, i.e., scene construction, robot localization, and scene comparison. For the first problem, “scene construction”, a clustering scheme is proposed for extracting a set of key frames from the surveillance environment. Each key frame is further divided into a set of patches, which forms a sparse representation for representing scene contents. In addition to the compression effect, the scheme can tackle the effects of misalignment and lighting changes well. For the localization problem, a novel patch matching method is proposed to reduce not only the size of the search space but also the size of the feature dimensions in similarity matching. To prune the search space, a set of projection kernels is used to construct a ring structure. Then, one order of time complexity in the similarity calculation can be reduced from the structure. After scene searching, the robot location is not always guaranteed to be successfully registered to the scene map. Thus, a novel spider-web map is proposed to tackle the effect of misalignment and then detect different exceptional scene changes from the videos. The proposed method has been rigorously tested on a variety of videos to demonstrate its superiority in object detection and abnormal scene change detection. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Unsupervised Hair Segmentation and Counting System in Microscopy Images

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (6411 KB)  

    This study focuses on the development of medical software for clinical applications using advanced image processing algorithms. Three critical issues of hair segmentation and counting are addressed in this study. First, the removal of any bright spots due to oil or moisture, which generate circular patterns in the middle of the hair and significantly affect the accuracy of determining the line. Second, two contacting or overlapping hairs are recognized and counted as a single hair. To solve this problem, we proposed a hair-bundling algorithm to calculate any concealed hairs. Finally, hairs may be wavy or curly, making the conventional Hough-based line detection algorithm unsuitable, since it suffers from parameter selections such as the minimum length of line segment, and distance between line segments. Our proposed hair counting algorithm is substantially more accurate than the Hough-based one, and robust to curls, oily scalp, noise-corruption, and overlapping hairs, under various white balance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Optimal-Distance based Transmission Strategy for Lifetime Maximization of Wireless Sensor Networks

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (333 KB)  

    An effective transmission strategy plays a vital role in maximizing the lifetime of wireless sensor networks (WSNs). To fulfill such a maximization aim, an optimal-distance based transmission strategy is put forward on the basis of ant colony optimization (ACO). The novelty of this strategy is threefold. Firstly, by introducing two notions, “most energy-efficient distance” and “most energy-balanced distance”, a local optimal-distance achievement mechanism is presented for not only high energy efficiency but also good energy balancing in WSNs; Secondly, by working out a network lifetime evaluation method, a global optimal-distance acquirement scheme is developed to achieve energy depletion minimization for sensor nodes with maximal energy consumption throughout the network. Finally, it is proved by simulations that our findings significantly outperform the state-of-the-art solutions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Dynamic Range Extension Technique for CMOS Image Sensors with in-pixel Dual Exposure Synthesis

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1268 KB)  

    This paper presents an in-pixel dual exposure synthesis technique to extend dynamic range of CMOS image sensors (CIS). The transfer transistor of the 4-T pixel acts as an overflow transistor in this proposed method. The full well capacity of photodiode can be very well controlled by biasing the transfer gate at different states. The long and short time exposed signals can be both stored in photodiode (PD) by adjusting the transfer gate voltage, and such the wide dynamic range signal can be obtained without extra readout operation. A proto chip with 64×48 pixel array is fabricated in 0.18μm CIS process. The sensor structure is based on a typical 4-T pixel image sensor with modified transfer gate driver and timing. This structure not only maintains the good features of 4-T pixels, such as good fill factor and low noise, but also achieves a wide dynamic range. The dynamic range of the proto chip is extended from 51.59dB to 90.53dB. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Reduction of Buffering Requirements: Another Advantage of Cooperative Transmission

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (67 KB)  

    Yet another advent of cooperative transmission is exposed in this paper. It is shown that cooperation lends itself to the reduction of buffer sizes of wireless sensor nodes. It is less likely to find the channel busy when cooperative transmission is employed in the network. Otherwise, in the lack of cooperation, the probability of build up of packet queues in transmission buffers increases. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Novel Sol-Gel Thin Film Constant Phase Sensor for High Humidity Measurement in the Range of 50-100 % RH

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1266 KB)  

    Present work proposes a new type constant phase sensor (CPS) for solving the problem of high humidity measurement. It is based on change in phase angle of the CPS with variation of humidity. The CPS having interdigitated electrode sandwiched between two identical thin films of γ-Al2O3 is fabricated by sol-gel dipcoating method. In the presence of relative humidity, the device shows fairly constant phase behavior over wide signal frequency and its fractional exponent changes by nearly 0.3 value at 90% RH from the initial value of 1 at dry humidity. Results show that the CPS is effective in measuring humidity in the range of 50 to 100 % RH at the signal frequency of 1 to 5 MHz. Finally the device has been interfaced with a simple fractional order differentiator circuit to measure the phase angle change of the device with change in relative humidity. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Multi-Focus Image Fusion Based on NSCT and Focused Area Detection

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1578 KB)  

    To overcome the difficulties of subband coefficients selection in multi-scale transform domain based image fusion and solve the problem of block effects suffered by spatial domain based image fusion, this paper presents a novel hybrid multi-focus image fusion method. Firstly, the source multi-focus images are decomposed using the non-subsampled contourlet transform (NSCT). The low frequency subband coefficients are fused by the Sum-Modified-Laplacian (SML) based local visual contrast, while the high frequency subband coefficients are fused by the local Log-Gabor energy. The initial fused image is subsequently re-constructed based on the inverse NSCT with the fused coefficients. Secondly, after analyzing the similarity between the previous fused image and the source images, the initial focus area detection map is obtained, which is used for achieving the decision map obtained by employing a mathematical morphology post-processing technique. Lastly, based on the decision map, the final fused image is obtained by selecting the pixels in the focus areas and retaining the pixels in the focus region boundary as their corresponding pixels in the initial fused image. Experimental results demonstrate that the proposed method is better than var-ious existing transform-based fusion methods, including gradient pyramid transform, discrete wavelet transform, NSCT, and a spatial-based method, in terms of both subjective and objective evaluations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Cross-spectrum Analysis based Scheme for Multiple Power Quality Disturbance Sensing Device

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1258 KB)  

    This paper presents a methodology of cross-wavelet transform aided Fischer linear discriminant analysis (FLDA) based feature selection and classification for sensing simultaneous occurrence of multiple power quality disturbances. A linear support vector machine is used for classification of the extracted features as it suits well with FLDA. This scheme is implemented in a general purpose microcontroller as a standalone module and the performance of the standalone module for sensing simultaneous occurrence of multiple Power Quality disturbances is judged by both online and offline testing. Results show that the performance is comparable with the results reported in the literatures. Moreover, the scheme is immune to real life uncorrelated noises due to incorporation of cross spectrum analysis in the feature extraction phase. The present method is generic in nature and can be implemented for any other microcontroller based applications addressing topologically similar problems. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • PMI based nonlinear H∞ estimation of unknown sensor error for INS/GPS integrated system

    Page(s): 1
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (5575 KB)  

    This paper deals with the problem of robust estimation for time-varying sensor errors of inertial navigation system (INS) and global positioning system (GPS) integration. A nonlinear strapdown INS error model is established to describe the behavior of the the integrated system. Under assumptions of time-varying bias and noise being L2 norm bounded, a robust H∞ nonlinear estimator by Krein space theory is proposed and, based on this, a proportional and multi-integral (PMI) H∞ estimator is developed for simultaneous estimation of the navigation states and sensor errors. Finally, a flight experiment is implemented to show the effectiveness of the proposed method. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

Aims & Scope

The IEEE Sensors Journal is a peer-reviewed, monthly online/print  journal devoted to sensors and sensing phenomena

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.