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Sensors Journal, IEEE

Issue 9 • Date Sept. 2012

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Displaying Results 1 - 25 of 36
  • [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): 2729 - 2730
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  • Table of contents

    Page(s): 2731 - 2732
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  • Microfluidic Platform for Electrical Monitoring of Enzyme Activity

    Page(s): 2733 - 2734
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (277 KB) |  | HTML iconHTML  

    In this letter, we present a scalable method based on the use of microfluidics and electrical conductivity measurement for monitoring the activity of an enzyme. This scalable method can be used for drug screening to test for the ability of an organic small molecule to inhibit the activity of an enzyme. Our method involves the use of electrodes integrated in a microchannel for the measurement of conductivity across the channel. An ac measurement is used to monitor the conductivity across the channel as the enzyme reaction proceeds. Here, we show the ability to measure these changes in conductivity and also the ability to distinguish between an active and inactive enzyme using an enzyme with two orders of magnitude reduced. View full abstract»

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  • Rapid and Sensitive Detection of Malaria Antigen in Human Blood With Lab-on-a-Chip

    Page(s): 2735 - 2736
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB) |  | HTML iconHTML  

    A novel lab-on-a-chip detection device, based on the properties of immunoagglutination, was modified to detect malaria in the human blood through histidine-rich protein 2, an antigen expressed only by Plasmodium falciparum. Utilizing Mie scattering detection, which is angle- and size-dependent, the extent of immunoagglutination could be accurately measured while the optical disturbance from the human blood was minimized. The presence of human serum albumin in the blood is believed to further stabilize the antibody-conjugated submicron beads and/or break off the larger agglutinated beads. The lowest detection limit was 1 pg/mL in 10% of whole blood (equivalent to 10 pg/mL in undiluted whole blood), a few orders of magnitude lower than other assays. The final device is compact, with a fast assay time of approximately 8 min. View full abstract»

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  • Optical Fiber Bus Protection Network to Multiplex Sensors: Experimental Validation of Self-Diagnosis

    Page(s): 2737 - 2743
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (462 KB) |  | HTML iconHTML  

    The experimental demonstration of a resilient wavelength division multiplexed fiber bus network to interconnect sensors is reported. The network recovers operation after failures and it performs “self-diagnosis,” the identification of the failed constituent(s) from the patterns of surviving end-to-end connections at its operating wavelengths. We provide clear evidence for the channel arrivals predicted by theory. In doing so, we explore the potential for spurious signals caused by reflections from broken fiber ends. Appropriate precautionary measures, especially the imposition of electronic thresholds at the receivers, can greatly reduce the scope for false diagnoses. Software to predict the failure site within the network from the arriving channels at the receivers is also reported. We describe how to coordinate self-diagnosis with protection switching so as to reduce the momentary service interruption. View full abstract»

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  • High-Speed Imaging of 2-D Ionic Diffusion Using a 16 ,\times, 16 Pixel CMOS ISFET Array on the Microfluidic Scale

    Page(s): 2744 - 2749
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (565 KB) |  | HTML iconHTML  

    We present an electrochemical high-speed measurement for direct observation of the mixing of ions in solution over a sensor surface. The method is applied to the determination of time-varying mixing and diffusion rates in microfluidic systems. The system generates high-speed videos of the analytes under investigation as they mix, without the need for any preliminary staining or labeling and has a pixel-to-pixel pitch of 14 μm. We demonstrate ion displacement phenomena on the surface of a Si3N4-passivated complementary metal oxide semiconductor ion-sensitive field effect transistor array device and also monitor the pH change induced by the addition of sulfuric acid to normal saline. These chemical videos are recorded with a frame rate of up to 333 frames/s. By evaluating the time-varying change in ionic concentrations across the surface of the chip, we calculate time-varying estimates of diffusivity coefficient values for the mixing analytes. View full abstract»

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  • Fiber-Optic Two-Photon Fluorescence Correlation Spectroscopy for Cell Flow Measurements

    Page(s): 2750 - 2755
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB) |  | HTML iconHTML  

    Quantification of sampled blood volume is important in rare circulating cell detection. A sensitive double-clad fiber probe is utilized for in situ blood flow velocity measurements and cell size analysis by means of two-photon excited fluorescence correlation spectroscopy (FCS). The ability to measure flow velocities of fluorescently labeled cells in whole blood has been demonstrated. By simultaneously monitoring the distinct fluorescence signals from the labeled cells and fluorescent microspheres with known size, the flow velocity can be calibrated in real time and the average cell size can be calculated. The measured flow velocities agree with the theoretical estimation. However, the measured cell size is larger than the typical size, which is due to the comparable size between the cell and the probe area. Translational FCS measurements on particles of different sizes are conducted to confirm the particle size effect on the measured transit times. View full abstract»

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  • Design and Development of a Novel Passive Wireless Ultrasensitive RF Temperature Transducer for Remote Sensing

    Page(s): 2756 - 2766
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1301 KB) |  | HTML iconHTML  

    A wireless, passive, and ultrasensitive temperature transducer is presented in this paper. The transducer consists of split ring resonators loaded with micro-bimorph cantilevers, which can potentially operate up to millimeter-wave frequencies (above 30 GHz). As the temperature changes, the bimorph cantilevers deflect and result in a shift of the resonant frequency of the split rings. A design is proposed, that has a maximum sensitivity of 2.62 GHz/μm, in terms of frequency shift per deflection unit, corresponding to a sensitivity of 498 MHz/°C for an operating frequency around 30 GHz, i.e., a frequency shift of 1.6% per °C. Theoretically, it's about two orders of magnitude higher than the existing sensors observed in the same class. This sensor design also offers a high Q factor and is ultra-compact, enabling easy fabrication and integration in micro-electromechanical systems technology. Depending on the choice of materials, the proposed designs can also be utilized in harsh environments. As a proof of concept, a prototype is implemented around 4.7 GHz which exhibits a frequency shift of 0.05%/°C, i.e., 17 times more sensitive than the existing sensors. View full abstract»

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  • Raw Material Classification by Means of Hyperspectral Imaging and Hierarchical Temporal Memories

    Page(s): 2767 - 2775
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (644 KB) |  | HTML iconHTML  

    The recently proposed hierarchical temporal memory (HTM) paradigm of soft computing is applied to the detection and classification of foreign materials in a conveyor belt carrying tobacco leaves in a cigarette manufacturing industry. The HTM has been exposed to hyperspectral imaging data from 10 types of unwanted materials intermingled with tobacco leaves. The impact of the HTM architecture and the configuration of internal parameters on its classification performance have been explored. Classification results match or surpass those attained with other methods, such as Artificial Neural Networks (ANNs), with the advantage that HTM are able to handle raw spectral data and no preprocessing, spectral compression, or reflectance correction is required. It is also demonstrated that an optimized configuration of the HTM architecture and internal values can be derived from the statistical properties of the hyperspectral data, allowing the extension of the approach to other classification problems. View full abstract»

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  • Investigation of Dispersion and Nonlinear Effects in Silicon Nanocrystal Slot Waveguides for Surface Optical Sensing

    Page(s): 2776 - 2783
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (515 KB) |  | HTML iconHTML  

    In this paper, an investigation of silicon nanocrystals-based sandwiched slot waveguides which are dispersion engineered for exciting optical solitons inside very short structures (only 3 mm long) is proposed. The possibility of using these structures for efficient surface sensing devices has been explored for the first time in cases of either air or water solution cover. View full abstract»

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  • Source Information Estimation Using Enemy's Single-Ping and Geographic Information in Non-cooperative Bistatic Sonar

    Page(s): 2784 - 2790
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1403 KB) |  | HTML iconHTML  

    Bistatic sonar operations on modern submarines are classified into cooperative and non-cooperative operations. In the cooperative operation, an active signal of a friendly ship is used and the source information is known a priori. In the non-cooperative operation, an active signal of the enemy is used, which makes it difficult to acquire the source information. The source information consists of the range, speed, course, and frequency of ping, which gives advantage to operating bistatic sonar. This paper suggests a novel method of estimating the source information with geographic information in the sea and the single-ping of the enemy. The source range is given using one geographic point. The source speed, course, and the frequency of the enemy's source signal are given using two geographic points. The performance of the proposed method is validated through simulation studies. View full abstract»

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  • Detection of Fluorophore-Tagged Recombinant Bovine Somatotropin (rbST) by Using a Silica-on-Silicon (SOS)-PDMS Lab-on-a-Chip

    Page(s): 2791 - 2798
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1035 KB) |  | HTML iconHTML  

    The presence of potentially harmful substances in milk is a concern for consumers. The discovery of recombinant DNA technology allowed the production of large quantities of recombinant bovine somatotropin (rbST), which is allowed to be used to increase milk and meat production in many countries. The use of rbST is controversial because of its potential effects on animal and human health. Use of the existing large instruments for the detection of rbST suffers disadvantages such as the need of large quantities of reagents, increased time of assays and most importantly, the high cost of equipment, etc. In this paper, a novel optical lab-on-a-chip (LOC) is proposed for the detection of a fluorophore-tagged rbST. The advantages of a silica-on-silicon platform for the optical waveguide and polydimethylsiloxane for microfluidics are exploited for the fabrication of a low-cost LOC. The tagging of rbST with two different types of fluorophores, such as FITC and Alexa-647, is carried out and used for detection in the proposed LOC. View full abstract»

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  • Enhanced Correlation Estimators for Distributed Source Coding in Large Wireless Sensor Networks

    Page(s): 2799 - 2806
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (876 KB) |  | HTML iconHTML  

    In this paper, we propose two estimators based on correlation parameters for the two key steps of a practical distributed source coding (DSC) scheme, namely: 1) the computation of the side-information at the receiver side and 2) the estimation of the required number of bits to compress the readings in order to guarantee a certain symbol error probability. We show that using the proposed estimators, the DSC algorithm performs better in terms of the compression rate and the symbol error rate. In particular, this improvement is especially significant when the number of snapshots used in the training phase is only slightly larger than the observation vector. However, when the number of snapshots is much higher than the observation dimension, our proposed estimators perform similarly to the classical estimators. View full abstract»

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  • Correlator Implementation for Orthogonal CSS Used in an Ultrasonic LPS

    Page(s): 2807 - 2816
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1725 KB) |  | HTML iconHTML  

    This paper presents a new architecture for the correlation of orthogonal complementary sets of sequences (OCSS) and their performance in an ultrasonic local positioning system (U-LPS). OCSS are sets of sequences whose addition of correlation functions has ideal properties, that makes interference-free code-division multiple access (CDMA) possible. They can be used to encode the signals emitted by a CDMA-based U-LPS, enhancing the performance of such systems in terms of immunity against noise, multipath propagation, and near-far effect. Also, the orthogonality of the codes offers an operation resistance to multiaccess interference, which endows the U-LPS with the capability of simultaneous emission from different beacons. On the other hand, the detection of OCSS codes can be performed by means of efficient algorithms. This paper presents an optimization of previous proposals allowing the simultaneous correlation of OCSS by using fewer operations and memory elements. Furthermore, the hardware implementation of the proposed optimization is also addressed, and an U-LPS based on this proposal is presented. View full abstract»

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  • Surface Modified {\rm CaTiO}_{3} Loaded in Polyaniline by Sodium Dodecyl Benzene Sulphonic Acid for Humidity Sensor

    Page(s): 2817 - 2823
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2596 KB) |  | HTML iconHTML  

    Polyaniline-CaTiO3 nanocomposites with their various weight percentages were prepared by chemical oxidative in situ polymerization technique. The prepared composites were characterized by Fourier transform infrared spectroscopy, scanning electronic microscope, and X-ray diffraction. The temperature-dependent dc conductivity of polyaniline-CaTiO3 nanocomposite was studied within the range of 40-200°C and found that 50 wt% shows high conductivity compared to other composites. Humidity sensor properties of polyaniline-CaTiO3 nanocomposite show better sensing properties and exhibit good linearity in sensing response curve, which discuss the implications of distortions and nonstoichiometry on their physical properties. Among all composites, 50 wt% of polyaniline-CaTiO3 nanocomposites show high sensitivity up to ~ 90% and their response-recovery times are 500 and 453 s, respectively. View full abstract»

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  • Low-Frequency Noise Characteristics of GaN Schottky Barrier Photodetectors Prepared With Nickel Annealing

    Page(s): 2824 - 2829
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (564 KB) |  | HTML iconHTML  

    In this paper, GaN Schottky barrier photodetectors (PDs) prepared with and without Ni treatment were fabricated. I-V and noise characteristics of these devices were then investigated. Comparing the GaN PDs with and without Ni treatment, it was found that GaN PDs prepared with Ni treatment can not only reduce dark current, but also enhance the UV-to-Vis rejection ratio. With an applied bias of -2 V, it was found that noise equivalent power (NEP) and detectivity (D*) for the PDs prepared without Ni treatment were 9.95 × 10-8 W and 1.59 × 107 cmHz0.5W-1, respectively. At the same applied bias, it was also found that NEP and D* for PDs prepared with Ni treatment were 1.74 × 10-11 W and 9.07 × 1010 cmHz0.5W-1, respectively. View full abstract»

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  • Electro-Thermal MEMS Switch With Latching Mechanism: Design and Characterization

    Page(s): 2830 - 2838
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2095 KB) |  | HTML iconHTML  

    This paper presents the design, fabrication, and characterization of a proprietary metallic microelectromechanical systems switch with unique latching and switching mechanisms that are driven electro-thermally by a set of V-shaped actuators (VSA) and modified Guckel U-shaped actuators. These distinctive actuators are specifically designed and uniquely integrated to provide desired large in-plane traveling distance and force for the switch contact and latching mechanisms. Due to the structural symmetry of the VSA, the out-of-plane displacements are minimized in the entire system. The latching mechanism reduces the total power consumption of the switch while providing a large mechanical contact force for a reliable switching function. This switch with latching capability only consumes power at the time of changing states. MetalMUMPs is employed to fabricate the device, in which electroplated nickel is used as the structural material. Using the metallic structure allows a low operating voltage. At 1.0 V with an electrical power of ~ 0.67 W, each nickel 4-arm VSA generates ~ 13.5-μm displacement and ~ 8-mN force. View full abstract»

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  • Application of an Optical Fiber Sensor on the Determination of Sucrose and Ethanol Concentrations in Process Streams and Effluents of Sugarcane Bioethanol Industry

    Page(s): 2839 - 2843
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (713 KB) |  | HTML iconHTML  

    In this paper, the measurement of process streams and effluents from the sugar-ethanol industry using an optical fiber sensor based on the Fresnel reflection principle is reported. Firstly, binary sucrose-water and ethanol-water solutions with predetermined concentrations were measured for calibration purposes. Secondly, the coproducts from various processing stages were analyzed in order to identify the sucrose or ethanol content. The measured data were processed by an artificial neural network model, which correlated the reflected intensity values to the sample concentration. The absolute error was calculated by a comparison between the nominal concentration values obtained by the plant laboratory analysis and the sensor response, yielding errors ≤ 3& wt% and ≤ 5.1 vol% for the sucrose and ethanol contents, respectively. The fiber sensor has the potential to provide reliable results even for samples with more complex compositions than pure sucrose or ethanol solutions, with perspectives of application on the several stages of the plant facility. View full abstract»

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  • Flexible UHF Resistive Humidity Sensors Based on Carbon Nanotubes

    Page(s): 2844 - 2850
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2259 KB) |  | HTML iconHTML  

    This paper presents the investigation of the resistive humidity-sensing properties of multi-walled carbon nanotubes (MWCNTs). MWCNTs functionalized by acid treatment (f-MWCNTs) exhibit rather high sensitivity in resistance toward humidity, owing to the presence of carboxylic groups on the nanotube surface. By integrating the f-MWCNTs resistor into a wireless sensor platform, flexible humidity sensors for ultra-high frequency applications are investigated. The operating frequency range of the sensor is dramatically increased from 600 MHz to 2 GHz by adjusting the resistor-electrodes' configuration. This enhancement is predominately attributed to the variation in parasitic capacitance between the resistor-electrodes. View full abstract»

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  • Humidity Sensing by Polymer-Loaded UHF RFID Antennas

    Page(s): 2851 - 2858
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1698 KB) |  | HTML iconHTML  

    Passive ultra high-frequency radio frequency identification tags, besides item labeling, are also able to exploit capability to sense the physical state of the tagged object as well as of the surrounding environment. Here, a new family of polymer-doped tags are proposed and fully characterized for the detection of ambient humidity. A sensitive chemical species based on PEDOT:PSS is used to load a shaped slot, carved into a folded-like patch tag. The communication and sensing capabilities of the resulting radio-sensor are investigated by means of simulation and measurements that show how to control and balance above opposite requirements by a proper deposition of the sensitive material. The device could have interesting applications in the assessment of the air quality within living and controlled rooms, in the monitoring of the conservation state of foods, in the preservation of walls, and even in the medical field, e.g., to monitor the healing of wounds. View full abstract»

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  • High Definition Image Pre-Processing System for Multi-Stripe Satellites' Image Sensors

    Page(s): 2859 - 2865
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2239 KB) |  | HTML iconHTML  

    High-resolution image sensors play an important role in today's satellites' remote sensing applications. This paper presents an image recombination and processing system for one-dimensional multi-strip complementary metal-oxide semiconductor image sensors (CISs.) The proposed system takes advantage of the satellites' linear moving property to control the exposure time of CIS and provides the real-time ability to generate 11 200× N high-resolution images for satellites' remote sensing. Using hardware accelerators coupled with versatile microprocessors, the architecture is able to offer processing capability as well as long-term maintainability for space-borne platforms. The details of hardware design to meet real-time requirement are presented. The prototype, which contains four strip CISs and field programmable gate array-based prototyping, was implemented to verify functionality and capability of real-time image acquisition and combination. The implementation results show that it is feasible to integrate the proposed system into a single chip. View full abstract»

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  • Data Integration Method for Multipath Ultrasonic Flowmeter

    Page(s): 2866 - 2874
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1106 KB) |  | HTML iconHTML  

    Compared to ultrasonic flowmeters with a single sound path, multipath ultrasonic flowmeters are capable of providing more accurate mean flow velocities on a cross-section of a pipe. This is accomplished by integrating the flow velocities derived from the measurements on multiple sound paths. In this paper, we proposed a data fusion based integration method to obtain the estimation of flow velocities on a cross-section of a pipe. The multipath ultrasonic flowmeter can provide a mean fluid velocity by taking the weighted average of the measured velocities of all sound paths. Compared to the traditional integration method, in which weights are determined according to the geometrical positions of sound paths, the proposed method considers the noise in the measured velocities on individual sound paths and determines the weights according to the variances of measured velocities on individual sound paths. This leads to a fused (integrated) flow velocity with a minimum mean square error. In addition, even if certain sound paths do not work properly, the proposed method can still provide a robust estimate of flow velocity on a cross-section of a pipe. View full abstract»

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  • Quasi-Distributed IFPI Sensing System Demultiplexed With FFT-Based Wavelength Tracking Method

    Page(s): 2875 - 2880
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (507 KB) |  | HTML iconHTML  

    In this paper, we fabricated a quasi-distributed intrinsic Fabry-Perot interferometric (IFPI) sensing array with the femtosecond laser. Each IFPI sensor is constituted by a pair of laser-induced internal reflectors and has a different cavity length. After multiplexing, IFPI sensors can be distinguished in the frequency domain for their different free spectral ranges. Next, a fast-Fourier-transform-based wavelength tracking method was proposed to demodulate the sensing signal. With a specially designed digital filter, frequency components corresponding to each sensor are extracted from the transmission spectra and are transformed back to the wavelength domain. Then the wavelength tracking method is utilized to demodulate the temperature information applied on the individual sensors. Experimental results show that the multiplexed sensors have good consistency and the temperature sensitivity is 11.24 pm/°C. 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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Editor-in-Chief
Krikor Ozanyan
University of Manchester
Manchester, M13 9PL, U.K.