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Sensors Journal, IEEE

Issue 9 • Date Sept.-oct. 2007

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Displaying Results 1 - 25 of 38
  • [Front cover]

    Publication Year: 2007 , Page(s): C1
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    Freely Available from IEEE
  • IEEE Sensors Journal publication information

    Publication Year: 2007 , Page(s): C2
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  • Table of contents

    Publication Year: 2007 , Page(s): 1217 - 1218
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  • Spectroscopic Sensor System for Quality Assurance of the Tube-To-Tubesheet Welding Process in Nuclear Steam Generators

    Publication Year: 2007 , Page(s): 1219 - 1224
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1529 KB) |  | HTML iconHTML  

    In a previous paper a new technique was proposed to allow real-time, online operation for arc-welding quality assurance based on plasma spectroscopy. In this paper, the proposed system has been used to determine the appearance of weld defects in the arc-welding nuclear steam generator tube-to-tubesheet process. The system was implemented in the facilities of Equipos Nucleares S.A. (ENSA), where several welding tests were performed on weld test coupons. Results will show the feasibility of the proposed system to be used in a real industrial scenario, presenting successful examples of weld defect detections. View full abstract»

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  • A Mixed-Voltage Sensor Readout Circuit With On-Chip Calibration and Built-In Self-Test

    Publication Year: 2007 , Page(s): 1225 - 1232
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2075 KB) |  | HTML iconHTML  

    This paper reports a mixed-voltage mixed-signal chip for interfacing multiple capacitive transducers to embedded processors in integrated microsystems. A programmable switched-capacitor readout circuit accommodates capacitive sensors from 16 fF to 40 pF and allows self-test and online calibration. The 20 mm2 chip has a sensitivity of 1.25 mV/fF and is realized in a 1 mum n-well BiCMOS 2 P/2 M process that permits high-voltage operation, large-value resistors, and nonvolatile on-chip memory. An on-chip charge pump generates voltages up to 30 V that permits transducer electrostatic self-test. In normal operation mode, the chip provides a fast sensor readout consuming only 90 nj of energy, making it suitable for portable applications. View full abstract»

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  • Calculation of the Response of Field-Effect Transistors to Charged Biological Molecules

    Publication Year: 2007 , Page(s): 1233 - 1242
    Cited by:  Papers (21)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (789 KB) |  | HTML iconHTML  

    Robust approximations are presented that allow for the simple calculation of the total charge and potential drop psi0 across the region of electrolyte containing charged biological macromolecules that are attached to the gate area of a field-effect transistor (FET). The attached macromolecules are modeled as an ion-permeable membrane in contact with the insulator surface, exchanging protons with the electrolyte as described by the site-binding model. The approximations are based on a new screening length involving the Donnan potential in the membrane and are validated by comparison to the results obtained by numerical solution of the one-dimensional Poisson-Boltzmann equation in the electrolyte and membrane. For gates covered with amphoteric materials such as SiO2, the high surface charge density sigma0 due to proton exchange at values of pH far from the point-of-zero charge is a nonlinear function of psi0, but psi0 and sigma0 are still linear functions of the semiconductor surface potential between the source and drain. Nonlinear expressions for the amphoteric site charge at the contacts can thus be applied effectively with the new approximations to calculate the current-voltage characteristics of the FETs using the strong inversion and charge-sheet models. View full abstract»

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  • New Thin-Film Multijunction Thermal Converter Design for Improved High-Frequency Performance

    Publication Year: 2007 , Page(s): 1243 - 1247
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (347 KB) |  | HTML iconHTML  

    New thin-film planar multifunction thermal converters (PMJTC) were developed to improve the high-frequency ac-dc transfer differences. The heater resistor and thermocouples of these PMJTCs were produced on different substrates: an AIN chip for the heaters and polyimide film for the thermocouples, using simple fabrication processes. The thermocouples were moved from the conventional high-potential heater position, and placed close to the ground electrode of the input circuit. This new configuration upgrades the performance of ac-dc transfer differences above 10 kHz by improving both the electromagnetic coupling between the heater and thermocouples and the output resistance of thermocouples. Using a high thermal conductivity AIN substrate, through which heat is conducted from the heater to the hot junctions of the thermocouples, almost the same sensitivity as that of PMJTCs on silicon is obtained. View full abstract»

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  • A Neuromorphic Chip That Imitates the ON Brisk Transient Ganglion Cell Set in the Retinas of Rabbits

    Publication Year: 2007 , Page(s): 1248 - 1261
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3066 KB) |  | HTML iconHTML  

    In this paper, a new CMOS design methodology is proposed to implement CMOS neuromorphic chips which imitate the ON brisk transient ganglion cell (GC) set of rabbits' retinas. The measurement results on the fabricated CMOS neuromorphic chip are consistent with the biological measurement results. Thus, the biological functions of the chip have been successfully verified. It can be used to understand more biological behaviors and visual language of retinas under different input optical images which have not yet been tested in biological experiments. Based on the results, the full GC sets of retina can be designed. Thus, many potential applications of retinal chips on motion sensors, computer vision, retinal prosthesis, and biomedical devices are feasible. View full abstract»

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  • A Plastic Optical Fiber Microbend Sensor Used as a Low-Cost Anti-Squeeze Detector

    Publication Year: 2007 , Page(s): 1262 - 1267
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    This paper presents a low-cost fiber optic anti-squeeze sensor, suitable for use in high-volume cost driven applications. The sensor, used as a car window anti-squeeze detector, complies with EC 2000/4/EC and U.S. Federal Motor Vehicle Safety Standard No. 118. The proposed design relies on microbend, loss induced in plastic optical fiber (POF). The sensor assembly employs only low-cost optoelectronic components readily in use by automotive and consumer markets. The lifetime tests have been performed on prototype sensors. The results show that the proposed design can easily reach and exceed 100 000 operational cycles even though it relies on flexible and all-polymer design. The proposed sensor design can be easily extended to other nonautomotive applications, such as protection devices in automatic door openers. View full abstract»

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  • A Proton Pumping Gate Field-Effect Transistor for a Hydrogen Gas Sensor

    Publication Year: 2007 , Page(s): 1268 - 1269
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (99 KB) |  | HTML iconHTML  

    A proton pumping field-effect transistor (FET), consisting of a triple layer gate structure of a Pd/proton conducting polymer/Pt, has been developed. The hydrogen sensitivity was controlled by the bias change between Pt and Pd. Furthermore, two kinds of methods for the readout of DC and AC modulation can be achieved. According to the decrement of the bias frequency, the modulated output was increased. This characteristic realizes a gas sensor with a self-check function. View full abstract»

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  • Low-Noise and High-Detectivity GaN-Based UV Photodiode With a Semi-Insulating Mg-Doped GaN Cap Layer

    Publication Year: 2007 , Page(s): 1270 - 1273
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (558 KB) |  | HTML iconHTML  

    GaN-based ultraviolet photodiodes with a semi-insulating Mg-doped GaN cap layer were fabricated and characterized. Dark leakage current of the aforementioned photodiodes was much smaller than that of the conventional ones without the Mg-doped GaN cap layer due to a thicker and higher potential barrier and less amounts of interface states after inserting the Mg-doped GaN cap layer. The ultraviolet to visible rejection ratio is 3.44 x 103 by inserting a semi-insulating Mg-doped GaN cap layer with a -IV applied bias. In this study, we also discuss the noise characteristics. It was found that minimum noise equivalent power and maximum detectivity of our photodiode were 1.2 x 10-12 W and 9.34 x 1011 cmHz0.5 W-1, respectively. View full abstract»

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  • Amorphous Silicon Sensors for Single and Multicolor Detection of Biomolecules

    Publication Year: 2007 , Page(s): 1274 - 1280
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (839 KB) |  | HTML iconHTML  

    In this paper, we report on a system for single and multicolor detection of biomolecules based on amorphous silicon photosensors. The system promises to be compact, portable, and low cost. It allows the quantitative detection without using optics for focusing both the excitation and the emitted radiation. The revealed biomolecules can be chemi- or naturally luminescent or can be labeled with fluorochromes. Here, we focus on the detection of DNA molecules labeled with a single or with two fluorochromes by using a p-i-n and a p-i-n-i-p amorphous silicon stacked structure, respectively. The device design has been optimized in order to maximize the signal-to-noise ratio and to match the sensor spectral response with the emission spectra of the fluorochromes. This optimization process has been carried out by means of a numerical device simulator, which takes into account the optical and electrical properties of the amorphous silicon. Detection limit in the order of a few nmol/l have been achieved for both the single and the two-color photosensors. Comparison with commercial measurement equipment shows the suitability of our system for practical applications. View full abstract»

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  • Gramicidin Ion Channel-Based Biosensors: Construction, Stochastic Dynamical Models, and Statistical Detection Algorithms

    Publication Year: 2007 , Page(s): 1281 - 1288
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1084 KB) |  | HTML iconHTML  

    This paper deals with the experimental construction, stochastic modeling, and statistical signal processing of a novel, artificially constructed biosensor comprised of biological ion channels. Such nanoscale biosensors have been built by incorporating dimeric gramicidin A (bis-gA) ion channels into bilayer membranes of giant unilamellar liposomes, and then excising small patches of the membrane loaded with ion channels. We present a stochastic model for the response of the biosensor and present statistical model validation tests to verify the adequacy of the model. We show that in the presence of specific target molecules, the statistics of the gating mechanisms of the gA channels are altered. By capturing the change in real time, we devise a maximum-likelihood detector to detect the presence of target molecules. To test the sensitivity of this model, we conducted patch-clamp experiments with two compounds known to inhibit conduction of the gA channels. We found experimentally that the real-time detection algorithm was able to accurately identify the addition of the compounds even when the alterations in the patch-clamp recordings were very small. This algorithm provides the sensitive detection system for ongoing development of lipid-based nanosensors. View full abstract»

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  • Low-Noise and High-Detectivity GaN UV Photodiodes With a Low-Temperature AlN Cap Layer

    Publication Year: 2007 , Page(s): 1289 - 1292
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (442 KB) |  | HTML iconHTML  

    Here, we present the characteristics of a novel GaN- based ultraviolet (UV) photodiode (PD) with a low-temperature (LT) AIN cap layer. The dark leakage current for the PD with the LT-AIN cap layer was shown to be about four orders of magnitude smaller than that for the conventional PDs. It was found that we could achieve larger UV to visible rejection ratio by inserting an LT-AIN cap layer. It was also found that we could improve minimum noise equivalent power and maximum normalized detectivity of the PD by inserting an LT-AIN cap layer. View full abstract»

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  • Noise Limitations of the Applications of Miniature Thermal Resistors

    Publication Year: 2007 , Page(s): 1293 - 1299
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (290 KB) |  | HTML iconHTML  

    The limitations of the performance of thermal resistors due to the electronic noises are investigated. Two applications of the thermistors are considered: the thermometer and the bolometer. The speed of the response of the probe is kept in mind in the calculation of the noise bandwidth. The effects of three different types of noises having white, 1/f, and Lorentzian frequency spectra are treated. The noise equivalent instabilities of the measured temperature are calculated and also converted to fluctuations of the power in bolometers. The detectable minimum of short energy pulses is also investigated. The numeric examples show that in the case of platinum resistors the main limitation of the accuracy is the thermal noise, while in semiconductor thermistors the excess noises can have significance. View full abstract»

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  • Sensitivity Tunable Inductive Fluid Conductivity Sensor Based on RF Phase Detection

    Publication Year: 2007 , Page(s): 1300 - 1301
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (220 KB) |  | HTML iconHTML  

    New results are presented for a sensitivity-tunable, inductive fluid conductivity sensor based on RF phase detection. An electronically controlled RF phase shifter allows the sensor to function in a wide range of conductivities from 2-70 mS/cm and helps tune the sensitivity of the response in a selected conductivity range. The noncontact nature of the sensor makes it suitable for corrosive fluids. Furthermore, the small size of the sensing element (1 inch. Sq X 6 mm thick) makes it suitable for compact in-line and hand held monitoring systems. View full abstract»

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  • Vehicle Localization Using Sensors Data Fusion Via Integration of Covariance Intersection and Interval Analysis

    Publication Year: 2007 , Page(s): 1302 - 1314
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1338 KB) |  | HTML iconHTML  

    Achieving an innovative integrated sensor fusion architecture with a robust vehicle navigation and localization using an extended Kalman filter, interval analysis and covariance intersection that can overcome the uncertainty in the system model and sensor noise statistics. There are various approaches to the problem, but here the focus is on an approach which can guaranteed performance of sensor-based navigation. The guaranteed performance is quantified by explicit bounds of position estimate of a ground vehicle. Ground vehicles generally carry dead reckoning sensors such as wheel encoders and inertial sensors, to measure acceleration and angle rate, while obstacle detection and mapmaking is done with time-of-flight ultrasonic sensors. Most of these sensors give overlapping or complementary information and sometimes are redundant as well, which offers scope for exploiting data fusion. The purpose here is to achieve data fusion for ground vehicles with low-cost sensors by forming an intelligent sensor system. This is accomplished by combining the sensors' measurements and processing these measurements with data fusion algorithms. The algorithms are complementary in the sense that they compensate for each other's limitations, so that the resulting performance of the sensor system is better than its individual components. View full abstract»

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  • A Microfluidic Device to Acquire Gaseous Samples Via Surface Tension Held Gas-Liquid Interface

    Publication Year: 2007 , Page(s): 1315 - 1316
    Cited by:  Papers (8)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (199 KB) |  | HTML iconHTML  

    We present a relatively simple and effective method for acquiring gaseous samples into microfluidic channels. Hydrophobic polymers are photopatterned on hydrophilic substrates. Due to surface tension, aqueous liquid is confined by the hydrophobic polymers, but not completely blocked by a physical wall, thus allowing an interface for gas-liquid interaction. Here, the mechanism is demonstrated by using hydrophobic (poly)iso-bornyl acrylate polymer patterns on hydrophilic glass substrates, and through a Nessler's reagent-ammonia reaction that exhibits changes in color and electrical resistance. View full abstract»

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  • A Low-Complexity Circuit for On-Sensor Concurrent A/D Conversion and Compression

    Publication Year: 2007 , Page(s): 1317 - 1325
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1017 KB) |  | HTML iconHTML  

    A low-complexity circuit for on-sensor compression is presented. The proposed circuit achieves complexity savings by combining a single-slope analog-to-digital converter with a Golomb-Rice entropy encoder and by implementing a low-complexity adaptation rule. The adaptation rule monitors the output codewords and minimizes their length by incrementing or decrementing the value of the Golomb-Rice coding parameter k. Its hardware implementation is one order of magnitude lower than existing adaptive algorithms. The compression circuit has been fabricated using a 0.35 muM CMOS technology and occupies an area of 0.0918 . Test measurements confirm the validity of the design. View full abstract»

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  • A Resonant Micromachined Magnetic Field Sensor

    Publication Year: 2007 , Page(s): 1326 - 1334
    Cited by:  Papers (20)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1225 KB) |  | HTML iconHTML  

    The design, modeling, and simulation of a novel micromachined magnetic field sensor are discussed. The sensor uses an electrostatic resonator whose fundamental resonant frequency is modified by a Lorentz force generated from the interaction of the sensor structure and the present magnetic field. The sensor was fabricated in a standard bulk micromachining process without the need for any additional processing steps. Since the sensor does not employ any magnetic materials, it does not exhibit hysteresis. A comprehensive model of the sensor behavior is derived which encompasses the interactions of the involved physical domains. Validity of the modeling results was verified by finite-element simulations, and later, through experiments. The sensitivities of the fabricated sensors are in the range of 48-87 Hz/T, depending on sensor structure and dimensions. The design of the sensor allows for its fabrication in many standard microelectromechanical system processes and is compatible with CMOS processes. The theoretical minimum detectable signal with current devices is on the order of 217 nT. Methods to improve the sensitivity of the current sensors are suggested. A linear response to a wide range of magnetic fields makes this design suitable for applications where large fields need to be measured with high resolution. View full abstract»

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  • High-Sensitivity Temperature Measurement With Miniaturized InSb Mid-IR Sensor

    Publication Year: 2007 , Page(s): 1335 - 1339
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1145 KB) |  | HTML iconHTML  

    This paper reports the development and evaluation of an InSb photovoltaic infrared sensor (InSb PVS) operating at room temperature. The InSb PVS consists of 700 InSb p+ - p- - n+ photodiodes connected in series, on a semi-insulating GaAs (100) substrate. An Al0.17rIn0.83Sb barrier layer between p+ and p- layers was used to reduce diffusion of photo-excited electrons. Cutoff wavelength was 6.8 mum and output signal was almost linear with irradiance up to 0.6 mW/cm2. Sensitivity of 67 muV/K and noise equivalent temperature difference of 2.2 mK/Hz1/2 was obtained at room temperature, which shows the sensor to be a suitable for noncontact thermometry. View full abstract»

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  • A Novel Planar-Type Biosensor for Noninvasive Meat Inspection

    Publication Year: 2007 , Page(s): 1340 - 1346
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1422 KB) |  | HTML iconHTML  

    A novel biosensor for inspection of meat in a noninvasive and nondestructive way has been fabricated and developed. The sensor has the planar interdigital structure and the consecutive fingers are connected to positive and negative electrodes, respectively. A novel sensor has been fabricated which provides improved results. The experimental results show the sensors have a great potential to estimate the fat content of meat in a noninvasive and nondestructive way. View full abstract»

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  • Detection of Moisture and Methanol Gas Using a Single Electrospun Tin Oxide Nanofiber

    Publication Year: 2007 , Page(s): 1347 - 1348
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (166 KB) |  | HTML iconHTML  

    This letter reports the fabrication of a gas sensor based on a single tin oxide nanofiber made from dimethyldineodecanoate tin using electrospinning and metallorganics decomposition techniques. The fabricated sensor has been used to detect moisture and methanol gas. It showed high sensitivity to both gases and the response times of the complete testing system are in the range of 108-150 s for moisture, and 10-38 s for methanol gas, respectively. View full abstract»

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  • Gas Sensing Interactions at Hydrogenated Diamond Surfaces

    Publication Year: 2007 , Page(s): 1349 - 1353
    Cited by:  Papers (6)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (604 KB) |  | HTML iconHTML  

    Hydrogenated diamond (HD) samples exhibit a p-type surface conductivity (SC) which is caused by transfer doping to an adsorbed liquid electrolyte layer. We report on gas sensing experiments showing that such samples selectively respond to NO2 and NH3 gases at room temperature. Successive substitution of H-terminated surface sites by O-termination ones causes an increase in both the sensor baseline resistance and the gas-induced resistance changes. Thermal desorption of the surface electrolyte layer, on the other hand, causes the sensor baseline resistance to increase and the gas sensing effect to disappear. Readsorption of the surface electrolyte reestablishes both the sensor baseline resistance and the gas sensing effect. Our results indicate that the gas sensing effect is caused by local pH-changes due to acid/base reactions of the adsorbed gas molecules in the surface electrolyte layer. It is argued that this dissociative gas sensing mechanism represents a valuable complement with regard to the established surface combustion mechanism that is operative on heated metal oxide surfaces. View full abstract»

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  • Built-In Self-Repair for Die-to-Die Misalignment of Multidie Space Sensors

    Publication Year: 2007 , Page(s): 1354 - 1355
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (262 KB) |  | HTML iconHTML  

    A space sensor often consists of a number of dies integrated side-by-side on a single substrate of package due to its high-resolution requirement. The sensing areas of these dies often cannot align both vertically and horizontally. This problem could cause serious image distortion if not handled properly. Trying to fix this problem at the base station on the earth is less effective since the expanded image data would have been too overwhelming. To overcome this problem, a low-cost built-in self-repair scheme is proposed in this paper. The misalignment amount at each die-to-die boundary is first decided continually, and then used to repair the distorted image on-the-fly right before they are stored into the image buffer. Experiments on a large number of test images indicate that a repair rate of almost 100% is achievable at only 2.43% area overhead. View full abstract»

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Aims & Scope

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

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Meet Our Editors

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