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Sensors Journal, IEEE

Issue 8 • Date Aug. 2008

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Displaying Results 1 - 22 of 22
  • Table of contents

    Publication Year: 2008 , Page(s): 1383 - 1384
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    Freely Available from IEEE
  • Estimating Displacement of Periodic Motion With Inertial Sensors

    Publication Year: 2008 , Page(s): 1385 - 1388
    Cited by:  Papers (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (634 KB) |  | HTML iconHTML  

    Inertial sensors, like accelerometers and gyroscopes, are rarely used by themselves to measure displacement. Accuracy of inertial sensors is greatly handicapped by the notorious integration drift, which arises due to numerical integration of the sensors zero bias error. A solution is proposed in this paper to provide drift free estimation of displacement from inertial sensors. View full abstract»

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  • Networked Sensors for Cargo Screening

    Publication Year: 2008 , Page(s): 1389 - 1396
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (168 KB) |  | HTML iconHTML  

    Sensors to monitor cargo are currently operated in standalone mode because of cost considerations, operational simplicity, and because potential benefits to having sensors share information do not appear to have been seriously considered in many cases. To identify situations where threat detection benefits offset networking costs (and where they do not), we describe a numerical algorithm for approximating the multidimensional integrals defining the false positive rates and detection probabilities for networked systems. The algorithm is sufficiently fast computationally to embed in optimization routines that search over sensor space (e.g., how to best augment an existing sensor network), as well as over threshold space (i.e., how to best determine alarm thresholds for the sensors) for both standalone and networked sensors. Results are applied to detection of elevated gamma and neutron counts. Circumstances under which networking is useful are characterized. View full abstract»

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  • Characterization of Integrated Tin Oxide Gas Sensors With Metal Additives and Ion Implantations

    Publication Year: 2008 , Page(s): 1397 - 1398
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (126 KB) |  | HTML iconHTML  

    Post-treatment of the sensing film in tin oxide gas sensor arrays is widely used to improve the selectivity in gas recognition applications. This letter describes the characterization study of an integrated tin oxide gas sensor array chip in which the sensing films are modified using metal additives and ion implantations. Measurement results reveal that metal additives present a higher impact on the sensor sensitivity compared with ion implantations. The latter has no significant effect on the sensing properties. The drift is increased for the sensors with only ion implantation compared with the ones with metal additives. An array combining both post-treatment techniques is expected to improve the overall recognition performance. View full abstract»

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  • Theoretical and Experimental Identification of Love Wave Frequency Peaks in Layered Structure ZnO/Quartz SAW Device

    Publication Year: 2008 , Page(s): 1399 - 1403
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (540 KB) |  | HTML iconHTML  

    In this paper, the layered structure ZnO/Quartz (90deg rotated ST-cut) is investigated theoretically and experimentally. Both waves, Rayleigh and Love, are analyzed. Dispersion curves of phase velocities, electromechanical coupling coefficient (K 2) and temperature coefficient of frequency (TCF) were calculated as a function of normalized thickness ZnO film (kh ZnO = 2pih ZnO /lambda) and the optimum value of h ZnO was determined for experimental study. Experimental results combined with simulation lead to clearly identify the generated waves and their higher modes in this structure except the mode 0 that shows comparable velocity for both Rayleigh and Love waves. The identification of the wave type was performed by studying the frequency response of the device with or without a droplet of water in the wave path. We also demonstrate that the highest elastic velocity is obtained for the mode 1 of the Love wave. This Love wave mode exhibits very interesting electrical characteristics, good K 2, high-frequency rejection, low TCF, and very low attenuation in liquid making it very attractive for gas and liquid sensor applications. View full abstract»

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  • Modeling Piezoresistive Microcantilever Sensor Response to Surface Stress for Biochemical Sensors

    Publication Year: 2008 , Page(s): 1404 - 1410
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1267 KB) |  | HTML iconHTML  

    This paper considers mechanical stress and strain in a piezoresistive cantilever sensor under surface stress loading, which is the loading condition that occurs in biochemical sensing applications. Finite element simulations examine the piezoresistor sensitivity due to changes in cantilever length, width, and thickness, and piezoresistor size, location, and depth. A few unexpected results are found. Unlike cantilevers designed for atomic force microscopy, cantilevers for biochemical sensing should be short and wide. While shallow piezoresistors offer good sensitivity, the piezoresistor may extend far into the thickness of the cantilever and still be quite effective. The paper concludes with comments on design guidelines for piezoresistive cantilever sensors. View full abstract»

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  • Synthesis of Airborne Laser Measurements for Navigation Algorithms

    Publication Year: 2008 , Page(s): 1411 - 1412
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    Airborne laser scanners are widely used for remote sensing and mapping and they are recently being applied to navigation of aerial and ground vehicles. Evaluation of new navigation algorithms in the presence of varying platform, sensor, and environment parameters requires high-fidelity measurement models of the airborne laser sensor. We present a procedure for the synthesis of airborne laser scanner measurements using aircraft flight trajectory, the scanner's mechanical and optical characteristics and the target environment model. View full abstract»

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  • Analog Neural Network Implementation for a Real-Time Surface Classification Application

    Publication Year: 2008 , Page(s): 1413 - 1421
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3154 KB) |  | HTML iconHTML  

    This paper deals with the implementation of a CMOS analog neural network (NN) that has to be integrated in a new kind of optoelectronic measurement system. The aim is to achieve real-time surface recognition using a phase-shift rangefinder and a neural network. NN architecture is a multilayer perceptron (MLP) with two analog input signals provided by the rangefinder, three processing neurons in the hidden layer, and one output neuron whose output voltage indicates the detected surface. As the complete structure is analog, no analog-to-digital conversions or signal processing between the rangefinder and the network is necessary. Furthermore, the 3.3-V voltage supply, relative to the chosen CMOS 0.35-mum technology, allows to reduce the system power consumption. This paper focuses on the implementation in an ASIC of an elementary part of the NN, called neuron, and on the achievement of the complete NN from the integration of three ASICs in a printed circuit board. Comparisons between ideal case, simulations and tests are detailed in order to validate the design and the good functioning of the complete structure. View full abstract»

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  • Nanostructured Metal Oxide Thin Films for Humidity Sensors

    Publication Year: 2008 , Page(s): 1422 - 1429
    Cited by:  Papers (26)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2544 KB) |  | HTML iconHTML  

    Capacitive humidity sensors were fabricated using countersunk interdigitated electrodes coated with amorphous nanostructured TiO2, SiO2, and Al2O3 thin films grown by glancing angle deposition. The capacitive response and response times for each sensor were measured. The sensor utilizing TiO2 exhibited the largest change in capacitance, increasing exponentially from ~ 1 nF to ~ 1muF for an increase in relative humidity from 2% to 92%. Adsorption and desorption response times were measured using flow rates of 2.5 l/min and were between 90 ms and 300 ms for the sensors studied here. A simple model of the capacitive response of the devices has been developed and used to calculate the dielectric constant of the combined system of our films and adsorbed water. The obtained dielectric constants are found to be much higher than bulk or literature values for similar systems. View full abstract»

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  • A 3.2 kHz, 14-Bit Optical Absolute Rotary Encoder With a CMOS Profile Sensor

    Publication Year: 2008 , Page(s): 1430 - 1436
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1482 KB) |  | HTML iconHTML  

    We have developed a 3.2 kHz, 14-bit optical absolute rotary encoder system using a profile sensor and a slit disc. The profile sensor, which we have designed for this purpose, is a unique CMOS area image sensor aimed at high-speed position detection of X and Y axes. Y axis profile data from the profile sensor is used for recognition of an index code on the slit disc, and X axis profile data is used for position detection of the index code. This combination of two-axis information enables high resolution even with a small number of index codes (64 indexes) and a small amount of digital calculations. Experimental results show that this system can detect rotation with an angular resolution of 14 bits (0.022deg) and a maximum detection speed of 3.2 kHz. View full abstract»

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  • Optical Absorption Measurements in Particle-Containing Ambients Using Gated Ratiometric Detection

    Publication Year: 2008 , Page(s): 1437 - 1444
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1663 KB) |  | HTML iconHTML  

    We demonstrate a ldquotrading time for signalrdquo approach for the measurement of species-specific optical transmission, in ambients rich in particulates, using the example case of a turbulent fluidized bed reactor. The method is introduced on the basis of Monte Carlo simulations, as well as analysis of experimental data, of beam propagation for a range of path lengths, and particle concentrations. In a particular embodiment for relative propane-concentration measurements, data is acquired only during gated time intervals of partial beam occlusion detected in real time. The digitized data streams from the signal and background beams is processed by algorithms performing gating, digital balanced detection, and dual wavelength ratiometry. This combination, implemented on inexpensive programmable hardware, results in at least an order of magnitude improvement in sensitivity. View full abstract»

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  • The Detection of Chemical Vapors in Air Using Optical Emission Spectroscopy of Pulsed Microdischarges From Two- and Three- Electrode Microstructures

    Publication Year: 2008 , Page(s): 1445 - 1454
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1389 KB) |  | HTML iconHTML  

    Emission spectroscopy of plasma-excited chemical species is widely used for generalized chemical analyses in bench-top systems. This paper explores the use of pulsed microdischarges between two and three electrode microstructures, which operate in air at atmospheric pressure, for use in handheld chemical analyzers. Pulsed microdischarges are fired between two-electrodes spaced apart by 0.2-2 mm. Synchronized optical sampling and time resolved spectroscopy are performed to capture the emission spectra from the microdischarge and its afterglow. The discharge spectra in air consist mainly of wide-band background spectra and line spectra from the nitrogen, and water vapor in air. The detection of vapors in air is limited by the relative strengths of representative lines compared to background spectra rather than by their absolute strength. The separate temporal characteristics of the line and background spectra present opportunities to improve detection. This concept is evaluated using isopropyl alcohol vapors (100 ppm) for which lines corresponding to CH fragments are detected with a handheld spectrometer despite the presence of air spectra. This paper also introduces a three-electrode (flashFET) configuration, which further reduces power consumption and electrode wear. Occupying an active area < 1 mm2, it employs a strategically located high-impedance gate electrode that permits the use of pulses < 100 V between the source and drain. The device consumes only 2.5 muJ/pulse at 140 Torr and 22.5 muJ/pulse at atmosphere, as compared to 470 muJ/pulse for two-electrode discharges. The operation of the flashFET as a gas sensor is evaluated using acetone vapors in air ambient. A response curve is obtained by measuring the 388.1 nm emission from acetone fragments for acetone concentrations ranging from 50 to 1000 ppm. View full abstract»

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  • Characterization of the Temperature Dependence of the Piezoresistive Coefficients of Silicon From {-}150,^{\circ} C to {+}125,^{\circ} C

    Publication Year: 2008 , Page(s): 1455 - 1468
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1615 KB) |  | HTML iconHTML  

    Stress sensing test chips are widely utilized to investigate integrated circuit die stresses arising from assembly and packaging operations. In order to utilize these test chips to measure stresses over a wide range of temperatures, one must have values of six piezoresistive coefficients for n- and p-type silicon over the temperature range of interest. However, the literature provides limited data over the desired range, and even the data at room temperature exhibit wide discrepancies in magnitude as well as sign. Thus, this work focuses on an extensive experimental study of the temperature dependence of the fundamental piezoresistive coefficients, pi11, pi12, and pi44, for both p- and n-type silicon from -150degC to +125degC, as well as a number of useful combined coefficients. Measurements were performed using stress sensors fabricated on (001) silicon. In order to minimize errors associated with misalignment with the crystallographic axes on (001) silicon wafers, anisotropic wet etching was used to accurately locate the axes. Four-point bending (4PB) was used to generate the required stress in strip-on-beam samples, and finite-element simulations were used to determine the states of stress in the silicon material. View full abstract»

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  • Cadmium Selective PVC-Membranes Sensor Based on 1, 2-Bis (Quinoline-2-Carboxamido) -4-Chlorobenzene as a Neutral Carrier

    Publication Year: 2008 , Page(s): 1469 - 1477
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (485 KB) |  | HTML iconHTML  

    The 1, 2-bis(quinoline-2-Carboxamido)-4-chlorobenzene (H2Clbqb) was used as an excellent ionophore in the construction of a cadmium(II)-selective PVC-based membrane sensor. The influences of membrane compositions on the potentiometric response of the electrodes have been found to substantially improve the performance characteristics. The best performance was obtained with a membrane composition of (H2Clbqb) (5%): PVC (31%): DBP (61%): NaTPB (3%). The sensor shows a Nernestian response for cadmium ions over a wide concentration range (1.0times106 to 1.0 times 10-1 mol.L-1) with slope of 30.3 plusmn0.4 mV decade1. The limit of detection was 8.0 times10-7 mol.L-1. It illustrates a relatively fast response time in the whole concentration range (< 10 s) and it can be used for at least 8 weeks without any divergence in potential. The electrode can be used in the pH range from 2.4 to 9.0. The selectivity coefficient of some alkali, alkaline earth, transition and heavy metal ions towards Cd2+ion have been determined. The results show proposed Cd sensor is selective over a number of mono, bi- and trivalent cations such as Pb2+, Fe3+, Ni2+, K+, and Mg2+. The analytical usefulness of the proposed electrode has been evaluated by its application in the determination of cadmium in real samples. It was successfully applied for the direct determination of Cd2+ in standard and real sample solutions. View full abstract»

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  • Enhanced Accuracy of Force Application for AFM Nanomanipulation Using Nonlinear Calibration of Optical Levers

    Publication Year: 2008 , Page(s): 1478 - 1485
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (795 KB) |  | HTML iconHTML  

    The atomic force microscope (AFM) has been widely used as a nano-effector with a function of force sensing to detect interaction forces between an AFM tip and a sample, thereby controlling the process of the nanomanipulation. However, both the extent and accuracy of force application are significantly limited by the nonlinearity of the commonly used optical lever with a nonlinear position-sensitive detector (PSD). In order to compensate the nonlinearity of the optical lever, a nonlinear calibration method is presented. This method applies the nonlinear curve fit to a full-range position-voltage response of the photodiode, obtaining a continuous function of its voltage-related sensitivity. Thus, interaction forces can be defined as integrals of this sensitivity function between any two responses of photodiode voltage outputs, instead of rough transformation with a single conversion factor. The lateral position-voltage response of the photodiode, a universally acknowledged puzzle, was directly characterized by an accurately calibrated force sensor composed of a tippless piezoresistive microcantilever and corresponding electronics, regardless of any knowledge of the cantilevers and laser measuring system. Experiments using a rectangular cantilever (normal spring constant 0.24 N/m) demonstrated that the proposed nonlinear calibration method restrained the sensitivity error of normal position-voltage responses to 3.6% and extended the force application range. View full abstract»

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  • A Tactile Sensor for Biomedical Applications Based on IPMCs

    Publication Year: 2008 , Page(s): 1486 - 1493
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1067 KB) |  | HTML iconHTML  

    In this paper, a first prototype of a multifunctional tactile sensor using ionic polymer metal composites (IPMCs) is proposed, designed, and tested. Two IPMC strips are used, one as an actuator and one as a sensor, both positioned in a cantilever configuration; working together they enable the system to detect the presence of a material in contact with it and to measure its stiffness. These sensing capabilities can be exploited in various biomedical applications, such as catheterism, laparoscopy and the surgical resection of tumors. Moreover, the simple structure of the proposed tactile sensor can easily be extended to devices in which a sensing tip for exploration of the surrounding environment is required. Compared with other similar tools, the one proposed works with a very low-power supply (the order of magnitude being a few volts), it needs very simple electronics, it is very lightweight and has a low cost. View full abstract»

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  • IEEE Sensors 2008

    Publication Year: 2008 , Page(s): 1494
    Save to Project icon | Request Permissions | PDF file iconPDF (642 KB)  
    Freely Available from IEEE
  • IEEE Foundation [advertisement]

    Publication Year: 2008 , Page(s): 1495
    Save to Project icon | Request Permissions | PDF file iconPDF (320 KB)  
    Freely Available from IEEE
  • Scitopia.org

    Publication Year: 2008 , Page(s): 1496
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | PDF file iconPDF (270 KB)  
    Freely Available from IEEE
  • IEEE Sensors Council Information

    Publication Year: 2008 , Page(s): 1497
    Save to Project icon | Request Permissions | PDF file iconPDF (33 KB)  
    Freely Available from IEEE
  • [Front cover]

    Publication Year: 2008 , Page(s): 1498
    Save to Project icon | Request Permissions | PDF file iconPDF (132 KB)  
    Freely Available from IEEE
  • IEEE Sensors Journal publication information

    Publication Year: 2008 , Page(s): 1499
    Save to Project icon | Request Permissions | PDF file iconPDF (37 KB)  
    Freely Available from IEEE

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.