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Sensors Journal, IEEE

Issue 5 • Date May 2010

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Displaying Results 1 - 23 of 23
  • [Front cover]

    Page(s): C1
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  • IEEE Sensors Journal publication information

    Page(s): C2
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  • Table of contents

    Page(s): 901 - 902
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  • A Cubic 3-Axis Magnetic Sensor Array for Wirelessly Tracking Magnet Position and Orientation

    Page(s): 903 - 913
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1220 KB) |  | HTML iconHTML  

    In medical diagnoses and treatments, e.g., endoscopy, dosage transition monitoring, it is often desirable to wirelessly track an object that moves through the human GI tract. In this paper, we propose a magnetic localization and orientation system for such applications. This system uses a small magnet enclosed in the object to serve as excitation source, so it does not require the connection wire and power supply for the excitation signal. When the magnet moves, it establishes a static magnetic field around, whose intensity is related to the magnet's position and orientation. With the magnetic sensors, the magnetic intensities in some predetermined spatial positions can be detected, and the magnet's position and orientation parameters can be computed based on an appropriate algorithm. Here, we propose a real-time tracking system developed by a cubic magnetic sensor array made of Honeywell 3-axis magnetic sensors, HMC1043. Using some efficient software modules and calibration methods, the system can achieve satisfactory tracking accuracy if the cubic sensor array has enough number of 3-axis magnetic sensors. The experimental results show that the average localization error is 1.8 mm. View full abstract»

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  • Eliminating the Temperature Dependence of the Response of Magnetoelectric Magnetic-Field Sensors

    Page(s): 914 - 917
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    Magnetic fields may be electrically detected by exploiting strain-mediated magnetoelectric coupling between a ferromagnet showing magnetostriction and a ferroelectric showing piezoelectricity. We argue that by electrically and thermally connecting two appropriately oriented anisotropic magnetoelectric elements that are identical, it is possible to cancel the strong unwanted pyroelectric response of the ferroelectric without cancelling the magnetoelectric response of interest. This result may be achieved using magnetoelectric elements that are merely similar, by measuring sensor voltage using an instrument with sufficiently low internal resistance. Using this strategy, we eliminate the influence of slow thermal fluctuations on the output of a sensor comprising two cheap magnetoelectric multilayer capacitors. This sensor can easily detect ~200 mT, suggesting the possibility of low-tech applications, e.g., detecting fields from cheap permanent magnets. View full abstract»

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  • Electrical Performance of Alumina Thin Films for High-Temperature Pressure Cells With a Metallic Body

    Page(s): 918 - 923
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (170 KB) |  | HTML iconHTML  

    Sputter deposited alumina thin films were investigated with regard to their performance as high-temperature electrical insulators. A target application of such dielectric films is in metal pressure sensor cells intended for high-temperature operation. The leakage behavior of sputtered alumina films was investigated by analyzing the temperature-dependence of the I-V characteristics of alumina films deposited on silicon and Haynes 230 substrates. Silicon substrates were used to analyze the leakage behavior under optimally controlled substrate conditions. Haynes 230, a nickel-based superalloy, was used as a substrate material to simulate conditions expected in a high-temperature metal pressure cell. In order to compare the dielectric performance under conditions of closely similar substrate quality, the topography of the Haynes 230 substrates was improved by applying a lapping process. From our results, we derive an estimate of the maximum operating temperature of metal pressure sensor cells. View full abstract»

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  • A Concept of a Sensor System for Determining Composition of Organic Solvents

    Page(s): 924 - 933
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    This paper presents the results of work on a gas sensor system for determining qualitative and quantitative composition of organic solvents. The system performs the analysis of gaseous mixtures, which are obtained by evaporating liquid solvents and therefore directly represent their composition. The system utilizes gas sensor array, which is built of Taguchi gas sensors (TGS). It provides patterns of measured solvents which are analyzed by pattern recognition module. The module employs multivariate statistical tools like discriminant function analysis (DFA) and partial least squares (PLS) regression. The determination of solvent composition is organized in a hierarchical structure. The concept of the system was experimentally verified using the example of two-component solvents. It was here demonstrated that the proposed system is capable of determining qualitative and quantitative composition of liquid solvents. View full abstract»

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  • Design of a Low-Frequency Microphone for Mobile Phones and Its Application to Ubiquitous Medical and Healthcare Monitoring

    Page(s): 934 - 941
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    This paper describes a novel strategy for providing ubiquitous medical and healthcare monitoring through the use of a mobile phone equipped with a low-frequency microphone sensitive to pressure waves in the frequency range of 0.1 Hz to 10 kHz. The mobile phone is placed in a sealed air cushion under the pillow or mattress of the subject's bed. The low-frequency microphone in the mobile phone picks up the signals from the subject's heartbeat, respiration, body movement and snoring and transmits them to a healthcare center where an auto-diagnosing system or specialist monitors the subject's health condition. View full abstract»

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  • Versatile Recognition Using Haar-Like Feature and Cascaded Classifier

    Page(s): 942 - 951
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1582 KB) |  | HTML iconHTML  

    This paper describes a world first versatile recognition algorithm suitable for processing images, sound and acceleration signals simultaneously with extremely low calculation cost while maintaining high recognition rates. There are three main contributions. The first is the introduction of a versatile recognition using Haar-like feature for images, sound and acceleration signals. The novel 1-D Haar-like features are proposed as very rough band pass filters for signals in temporal dimension. The second is a content-aware classifier which is based on the cascaded classifier and positive estimation. The cascaded classifier with positive estimation is introduced to allow a sensor node to computes finely only when the inputs are target-like and difficult to recognize, and stop computing when inputs obtain enough confidence. The third is a method of intermediate signal representation called Integral Signals and ¿-Integral Signals for calculation cost reduction in Haar-like feature based recognition. In this paper, the proposed recognition is experimented for a variety of sound recognition applications such as speech/non-speech, gender, speaker, emotion, and environmental sounds recognition. The preliminary results on human activity recognition and face detection are also given to show the versatility. The proposed algorithm yields sound recognition performance comparable to the conventional state-of-art method called MFCC while 96%-99% efficient in terms of the total amount of add and multiply operations. The proposed algorithm is evaluated with a versatile recognition processor implemented in 90-nm CMOS technology . For speech/nonspeech classification on 8-kHz 8-bit sound, the power consumption per frame rate is 0.28 ¿W/fps. When the sensor is operated with a duty ratio of 1%, the power consumption is reduced to 28.5 ¿W. View full abstract»

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  • Collection of Gaseous and Aerosolized Samples Using Microfluidic Devices With Gas–Liquid Interfaces

    Page(s): 952 - 959
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    We demonstrated methods for collecting gaseous samples and aerosolized particles into microfluidic channels. Gas-liquid interfaces created by surface tension permit analytes to transfer from the environment into a microfluidic channel. In one structure of our design, hydrophobic-hydrophilic boundaries created a channel of liquid confined by gas-liquid interfaces in which analytes were collected. In another structure, circular air pillars within microfluidic channels were created by surface tension forces for analytes collection. A multileveled structure could be formed by the air pillar design with a simple process, enabling it to collect and separate multiple analytes at a time. Both structures were tested with ammonia as a gaseous sample and Kool-Aid as aerosolized particles. The sample acquisition capabilities of the devices were demonstrated by extensive testing with gaseous NH3, using Nessler's reagent as the collecting fluidic stream, and with aerosolized Kool-Aid particles, using deionized (DI) water as the collecting fluidic stream. Increasing the exposed fluidic surface area to the environment effectively increased collection efficiency of the devices. This was confirmed by a resistance study between different sets of designs of both structures. Real-time analysis potential was also demonstrated through measurement of DI water resistance by collecting varying concentrations of gaseous NH3. View full abstract»

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  • Predicting Millimeter Wave Radar Spectra for Autonomous Navigation

    Page(s): 960 - 971
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3685 KB) |  | HTML iconHTML  

    Millimeter Wave (MMW) radars are currently used as range measuring devices in applications such as automotive driving aids (Langer and Jochem, 1996), (Rohling and Mende, 1996), the mapping of mines (Brooker et al., 2005) and autonomous field robotics (Brooker, 2001), (Langer, 1996). This recent interest is largely due to the advantages MMW radars offer over other range measuring sensors, as their performance is less affected by dust, fog, rain or snow and ambient lighting conditions. MMW radars can provide received signal strength values, at all discrete range intervals, within the working range of the radar (Clark and Durrant-Whyte, 1997), (Scheding et al., 2002). The received power versus range spectra hence contain useful range to target information, but are also corrupted by noise. User defined stochastic algorithms can then be implemented, which exploit this rich data to improve object detection and mapping performance. This is in contrast to many other range measuring devices which typically internally threshold received signals, to provide single hard decisions only, on the estimated range to objects (Mullane, 2007). This paper addresses the issues of predicting the power-range spectra from MMW radars which use the Frequency Modulated Continuous Wave (FMCW) range estimation technique. This is important for two reasons. First, in automotive and autonomous robotic applications, such sensors are used in conjunction with vehicle navigation and map state estimation filters. This is so that (typically uncertain) vehicle motion knowledge can be optimally fused with the noisy sensor information, to infer estimates of the state of interest (typically, the vehicle's pose (position and orientation) and/or information of the surrounding object locations). Hence, it is essential that predicted power versus range spectra can be computed, to apply a Bayesian recursive estimation framework, based on previous measurements, and uncertain vehicle motion information. Second, it- is extremely useful to be able to simulate MMW radar data, given certain environmental configurations. This aids the development of reliable object detection algorithms, based on theoretical sensor and noise models, which can then be applied more effectively to real MMW radar data. View full abstract»

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  • Capacitive-Type Flexible Linear Encoder With Untethered Slider Using Electrostatic Induction

    Page(s): 972 - 978
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    A novel capacitive linear encoder characterized by its untethered slider is presented. The main components are made of flexible printed circuit films measuring 0.2 mm in thickness that allows the sensor to be set up in thin interspaces or on curved surfaces. The sensor consists of a long receiver film and a short transmitter film, respectively containing four-phase and two-phase electrodes; the transmitter is used as a slider and the receiver as a stator. To realize an untethered slider, the sensor employs a unique approach; electric power is supplied to the transmitter film by electrostatic induction, which removes electric wires from the slider. This untethered slider can facilitate sensitive applications where a mechanical disturbance caused by an electric wire can be a problem. The principle was verified using a prototype encoder, which showed an error of ± 4 ¿ m. View full abstract»

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  • Amperometric ATP Biosensors Based on Coimmobilizations of p-Hydroxybenzoate Hydroxylase, Glucose-6-Phosphate Dehydrogenase, and Hexokinase on Clark-Type and Screen-Printed Electrodes

    Page(s): 979 - 983
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    Two types of amperometric trienzyme ATP biosensors were developed based on new combinations of enzymes and electrodes by using the coimmobilizations of p-hydroxybenzoate hydroxylase (HBH), glucose-6-phosphate dehydrogenase (G6PDH), and hexokinase (HEX) on a Clark-type oxygen electrode and on a screen-printed electrode. The principles of the determinations are as follows: HEX transfers the phosphate group from ATP to glucose to form glucose-6-phosphate. G6PDH catalyzes the specific dehydrogenation of glucose-6-phosphate by consuming NADP+. The product, NADPH initiates the irreversible hydroxylation of p-hydroxybenzoate by HBH to consume dissolved oxygen which results in a detectable signal on a Clark-type electrode and generate 3, 4-dihydroxybenzoate which results in a detectable signal on a screen-printed electrode. Both sensors show high-performance characteristics with broad detection ranges, short measuring times and good specificities. View full abstract»

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  • Precise Alignment of a Magnetic Sensor in a Coordinate Measuring Machine

    Page(s): 984 - 990
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    In order to measure strongly inhomogeneous magnetic fields it is straight forward to mount a magnetic sensor in a coordinate measuring machine (CMM). A scan of the field provides the components of the field vector w.r.t. the coordinates of the CMM reference frame. However, assembly tolerances of the sensor impair the field measurement. This paper explains a calibration procedure how to determine the misalignment of the sensor w.r.t. the reference frame of the CMM. To this end, the sensor needs at least two and for high accuracy four sensor elements on a single die with negligible hysteresis and offset. The calibration procedure requires a reference magnetic field with certain symmetry properties. A magnetic circuit generating this field is shown. Inaccuracies of the sensor elements and a curvature of the die surface are investigated theoretically and exemplary and result in a maximum error smaller than ±0.027°. View full abstract»

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  • CMOS Capacitive Sensors With Sub- \mu m Microelectrodes for Biosensing Applications

    Page(s): 991 - 996
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    Miniaturized complementary metal-oxide semiconductor (CMOS) capacitive sensors presented in this work are capable of providing sensitive detection in the sub-nM range for biosensing applications. A convenient post-CMOS fabrication process is proposed to make sub-μm interdigitated microelectrodes covered by inter-metal dielectric layer as the sensing interface. Capacitance change due to the electrode-analyte impedance is detected by the integrated continuous-time sensing circuit. For immunodetection of mouse IgG and anti-mouse IgG enhanced by 25% gold nanoparticles, the produced interface capacitance changes after specific bindings were -4, -7.4, and -17 fF for the 13-, 95-, and 925-fF microelectrode designs, respectively. Detection of the 200-nM neurotransmitter dopamine (DA) showed interface capacitance changes of 0.22,1.46, and 22 fF for the three designs. Based on the measured circuit noise of 14.2 μV/Hz1/2, the minimum detectable capacitance changes were 0.3, 2.9, and 22.5 aF, equivalent to detectable DA concentrations of 309, 394, and 203 pM, respectively. View full abstract»

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  • Silicon on Insulator Diode Temperature Sensor– A Detailed Analysis for Ultra-High Temperature Operation

    Page(s): 997 - 1003
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    Silicon diodes can be used for accurate temperature monitoring up to higher temperatures in a variety of sensors such as micro-machined resistive and calorimetric gas sensors, thermal flow sensors, exhausts, etc. This paper investigates the performance of a diode temperature sensor when operated at ultra high temperatures (up to 780°C ). A low leakage silicon on insulator (SOI) diode was designed and fabricated in a 1.0 ¿m CMOS (complementary metal oxide semiconductor) process. The diodes were suspended within a dielectric membrane [formed by post CMOS deep reactive ion etching (DRIE)] for efficient thermal insulation. A CMOS compatible micro-heater was integrated with the diode on the dielectric membrane for local heating. It was found that the diode forward voltage exhibited a linear dependence on temperature as long as the reverse saturation current remained below the forward driving current. We show experimentally that the maximum temperature up to which the linearity of diode's forward voltage output is maintained can be as high as 550°C . Long term continuous operation at high temperatures (400°C and 500°C ) showed good stability of the diode voltage drop. Finally, we present a detailed theoretical analysis that helps to determine the maximum operating temperature for the diode and also explains the presence of nonlinearity factors in diode voltage output at ultra high temperatures. View full abstract»

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  • Influence of Oxygen Content and Post-Deposition Annealing on Structural and Sensing Characteristics of \hbox {Tm}_{2}\hbox {O}_{3} Thin Membranes for pH Detection

    Page(s): 1004 - 1011
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    In this paper, we describe an electrolyte-insulator-semiconductor (EIS) device prepared from Tm2O3 sensing membranes deposited on Si (100) substrates through reactive sputtering. X-ray diffraction, X-ray photoelectron spectroscopy, and atomic-force microscopy were used to study the chemical and morphological features of these films as functions of the growth conditions (argon-to-oxygen flow ratios of 10/20, 15/15, and 20/10; temperatures ranging from 700 to 900°C). The Tm2O3 EIS prepared under an Ar/O2 flow ratio of 15/15 with subsequent annealing at 800°C exhibited a higher sensitivity (58.02 mV/pH, in the solutions from pH 2 to 12), a smaller hysteresis voltage (2 mV in the pH loop 7 ¿ 4 ¿ 7 ¿ 10 ¿ 7), and a lower drift rate (1.04 mV/h in the pH 7 buffer solution) than those of the other conditions. We attribute this behavior to the optimal oxygen content in this oxide film forming a strong (622) crystallographic orientation of Tm2O3, a thin low-k interfacial layer, and a large surface roughness. View full abstract»

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  • Numerical Study on Strain Measurements Using the Improved Bonding Fiber Bragg Grating

    Page(s): 1012 - 1018
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    This study suggests an improved bonding method for a surface mounted fiber Grating strain sensor to significantly reduce the mechanical influences from the surrounding cement of a glued fiber grating in the conventional bonding method. The linear relationship between the voltage signals and the average strains within the glue-free fiber grating is the advantage of the improved bonding method over the conventional bonding method (distributing cement along the full fiber grating). The numerical computations based on the coupled-mode theory were conducted to obtain the reflection spectra of a fiber grating, that are induced from different strain fields. The one-dimensional strain fields, that vary linearly within a fiber grating, were considered in this research. In addition, the filtered spectral power interrogation system to obtain the voltage signals from an optical fiber framework was taken in consideration. The filtered spectral power interrogation system is economic, compact, and suitable for on site measurements compared with other systems such as the optical spectrum analyzer. For a glued fiber grating, results show that the distortions in shape and the dilations in area of its reflection spectrum are because of the varied strain gradients within the grating during a strain history. Also, the central wavelength shifts of a reflection spectrum are related to the average strains within a fiber grating. In applications using the improved bonding fiber grating strain sensor, its linear relationship between the voltage signals and the average strains shows the feasibility of obtaining calibrations by using a commonly used resistance strain gauge. View full abstract»

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  • A Bistable Threshold Accelerometer With Fully Compliant Clamped-Clamped Mechanism

    Page(s): 1019 - 1024
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    In the IEEE SENSORS JOURNAL, vol. 7, no. 8, pp. 1102-1109, 2007, we presented an analyzing method for a threshold accelerometer based on the fully compliant bistable mechanism composed of post-buckling beams with both ends fixed. The critical buckling phenomenon and bistability of the compliant buckling structures are considerably suitable for mechanically sensing the threshold acceleration, and eliminating the electrical power needed for retaining the stable state. Based on the bistability of the fully compliant clamped-clamped mechanism, a threshold accelerometer which can sense the threshold deceleration (cutoff acceleration) after being triggered is designed and fabricated in this paper. The accelerometer mainly consists of a contact, an inertial mass, and two parallel clamped-clamped beams with a length of L and an initial angle ¿. A mini rotating test bench is designed to test the sensing capability of threshold acceleration. The threshold acceleration and deceleration for triggering and cutting-off the accelerometer are 9.7 g and -3.1 g in experiments, which deviate from the design values of 10.0 g and -3.0 g with only 3.0% and 3.33%, respectively. The capabilities of accurate threshold sensing and stable state retaining validate the feasibility of introducing the post-buckling compliant beams in designing threshold accelerometers. And, the accordance in the five experiment results also shows that the repeatability and structural simplicity of the designed threshold accelerometer ensure its reliability and applicability in engineering. View full abstract»

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    Page(s): 1025
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    Page(s): 1026
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    Page(s): 1027
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    Page(s): C3
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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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Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.