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Instrumentation and Measurement, IEEE Transactions on

Issue 12 • Date Dec. 2008

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Displaying Results 1 - 25 of 35
  • Table of contents

    Page(s): C1 - 2685
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  • IEEE Transactions on Instrumentation and Measurement publication information

    Page(s): C2
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  • Editor-in-Chief's Year-End Message

    Page(s): 2686 - 2687
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  • List of Reviewers

    Page(s): 2688 - 2696
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  • An Economic Offline Technique for Estimating the Equivalent Circuit of Aluminum Electrolytic Capacitors

    Page(s): 2697 - 2710
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2368 KB) |  | HTML iconHTML  

    This paper presents an experimental technique that allows the determination of both reactance and equivalent series resistance (ESR) intrinsic values of aluminum electrolytic capacitors. The ESR is one of the most critical problems of static converters that operate near the resonance frequency of electrolytic capacitors. An increased ESR value leads to a significant increase in the alternate component of the output voltage, requiring constant action of the control system. In addition, manufacturers usually do not give the ESR value, but do give the maximum dissipation factor (DF), at the operating frequency of 120 Hz. From the DF, it is possible to determine the maximum ESR value at 120 Hz. Since the ESR value changes with frequency, and static converters operate at much higher ranges, designers need to compute its value at the operating frequency of these converters to reach the best design proposal. Moreover, almost all capacitor manufacturers give the capacitance value with a tolerance of 20%, whereas the proposed technique permits computation of its value with higher accuracy. Additionally, at low frequencies, if the ESR value of the capacitor is known, through its comparison with the maximum value given by the manufacturer, it is possible to estimate its condition. To validate the proposed technique and to demonstrate its applicability, some experimental results are presented and compared with the ones obtained with an impedance gain-phase analyzer and the manufacturers' specifications for four different capacitors. View full abstract»

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  • Design and Characterization of Solar-Assisted Heating Plant in Domestic Houses

    Page(s): 2711 - 2719
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1007 KB) |  | HTML iconHTML  

    This paper deals with the development and characterization of an innovative domestic heating system that is driven by a solar-assisted heat pump to increase system efficiency. A suitable online measurement system of overall observable quantities has been integrated in the plant to give accurate and updated measurements of all the variables that are of interest to the whole system. A more detailed analysis of the quantities that mainly influence system performance has been carried out, and a suitable mathematical model that is able to describe and control the behavior of the interesting phenomena has been developed. The amount of heating energy depends on the local weather conditions. In the thermal plant proposed here, there is a solar energy harvesting device; this kind of plant needs a highly sensitive control system because of the great sensitivity of solar-powered systems to climatic variations. The use of the proposed system allows monitoring and controlling of the heating conditions of domestic houses without high environmental impact and energy costs. View full abstract»

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  • Stable Approximation of Unstable Transfer Function Models

    Page(s): 2720 - 2726
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (218 KB) |  | HTML iconHTML  

    The result of a system identification experiment is usually a parametric continuous-time (s-domain) or discrete-time (z-domain) model. Due to noise on the measurements and/or nonlinear distortions, this model can be unstable. If an additional delay is added to the unstable system, then experience shows that a stable approximation with small approximation error can be obtained. In this paper, a new numerical algorithm is proposed for finding a delay that gives a stable result. Contrary to classical approaches, it needs fewer gradientlike steps during the approximation process. View full abstract»

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  • Parameter Sensitivity and Measurement Uncertainty Propagation in Torque-Estimation Algorithms for Induction Machines

    Page(s): 2727 - 2732
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (868 KB) |  | HTML iconHTML  

    This paper studies measurement uncertainty propagation and parameter sensitivity based on a torque-estimation model for induction machines. The model is based on the equation that describes the interaction of rotor flux and rotor currents. Contrary to classical schemes for induction motor control, this is an open-loop scheme; however, the model still requires different machine parameters. Therefore, the parameter sensitivity of the model is performed. For validation, the model is implemented in the real-time environment dSPACE, and a test induction machine is subjected to different combinations of speed and torque profiles. The identified model can be used to replace mechanical torque-measurement devices or as a backup for a low-cost torque sensor. View full abstract»

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  • A Methodology to Test Instrument Software: An Automotive Diagnostic System Application

    Page(s): 2733 - 2741
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    This paper aims to describe a new methodology specifically designed for testing measurement and diagnostic software. A black-box procedure allows the user to verify whether the functional requirements of a software module under test are fulfilled. The robust experimental design techniques and statistical theories implemented to generate the software input test sets are described in detail. The reliability of the testing methodology is estimated by applying it to diagnostic software in wide use throughout the automotive industry. The results of validation tests carried out on data from a car engine measurement system are reported and analyzed. View full abstract»

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  • One-Way Delay Measurement: State of the Art

    Page(s): 2742 - 2750
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (382 KB) |  | HTML iconHTML  

    Nowadays, the evaluation of performance measurement in computer networks is an important issue. To ensure the quality of service of the network communication, one of the most important network performance parameters is the one-way delay (OWD). For accurate OWD estimation, it is essential to consider some parameters that can influence the measure, such as the operating system and, in particular, the threads, which are concurrent with the measurement application. Moreover, OWD estimation is not an easy task, because it can be affected by synchronization uncertainties. This paper aims to review the different solutions proposed in the scientific literature for OWD measurement. These solutions adopt different methods to guarantee a reasonable clock synchronization based on the Network Time Protocol, the Global Positioning System, and the IEEE 1588 Standard. These different approaches are critically reviewed, showing their advantages and disadvantages. View full abstract»

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  • Processing of Ultrasonic Echo Envelopes for Object Location With Nearby Receivers

    Page(s): 2751 - 2755
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1000 KB) |  | HTML iconHTML  

    Ultrasonic sonar systems are commonly used for obstacle location in robotics and autonomous navigation applications. When irregular objects have to be located, optimal algorithms for time-of-flight (TOF) estimation, like cross correlation, might be unreliable since complex reflecting surfaces can destroy phase coherence during the duration of the echo. Direct threshold methods acting on the envelope are equally inaccurate. This paper proposes a simple digital processing technique, called selective normalization, that works with the signal envelope and robustly determines the differential TOF (DTOF) of the ultrasonic echoes received by two or more nearby transducers. It is empirically demonstrated that this method improves the positioning accuracy of nonpointlike objects. View full abstract»

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  • The Complete Design of Microstrip Directional Couplers Using the Synthesis Technique

    Page(s): 2756 - 2761
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (827 KB) |  | HTML iconHTML  

    A symmetrical microstrip directional coupler design using the synthesis technique without prior knowledge of the physical geometry of the directional coupler is analytically given. The introduced design method requires only the information of the port impedances, the coupling level, and the operational frequency. The analytical results are first validated by using a planar electromagnetic simulation tool and then experimentally verified. The error between the experimental and analytical results is found to be within 3% for the worst case. The design charts that give all the physical dimensions, including the length of the directional coupler versus frequency and different coupling levels, are given for alumina, Teflon, RO4003, FR4, and RF-60, which are widely used in microwave applications. The complete design of symmetrical two-line microstrip directional couplers can be obtained for the first time using our results in this paper. View full abstract»

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  • ADC Testing With Verification

    Page(s): 2762 - 2768
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB) |  | HTML iconHTML  

    An important method for analog-to-digital-converter (ADC) testing is sine wave fitting. In this method, the device is excited with a sine wave, and another sine wave is fitted to the samples at the output of the ADC. The acquisition device can be analyzed by looking at the differences between the fitted signal and the samples. The fit is done using the least-squares (LS) method. If the samples of the error (the difference between the fitted signal and the samples) were random and independent of each other and of the signal, the LS fit would have very good properties. However, when the error is dominated by quantization error, particularly when a low bit number is used or the level of the measured noise is low, these conditions are not fulfilled. The estimation will be biased, and therefore, it must be corrected. The independence of the error samples is more or less true if the sine wave is noisy or dither is used. In these cases, the correction is not necessary. Therefore, it is reasonable to analyze the effect of the potentially unnecessary correction to noisy data, and it is desirable to determine the magnitude of the noise from the measurements. In this paper, these two questions are investigated. The variance of the corrected estimator is investigated, and a new noise estimation method is developed and analyzed. View full abstract»

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  • Real-Time Digital Multifunction Instrument for Power Quality Integrated Indexes Measurement

    Page(s): 2769 - 2776
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1057 KB) |  | HTML iconHTML  

    In this paper, the design and implementation of a high-performance, real-time power quality (PQ)-measuring instrument based on a digital signal processor is discussed. The system is realized according to the latest standards about PQ monitoring, and it can be reconfigured for future developments of the standards. The instrument is particularly implemented to operate in stand-alone mode, and it is interfaced with a hardware module that adopts Transmission Control Protocol/Internet Protocol to exchange information and data. The main advantage of the realized device is the possibility to perform a comprehensive PQ monitoring that adopts a single low-cost instrument. Finally, this paper reports some preliminary experimental results of the accuracy characterization of an implemented prototype of the proposed instrument. View full abstract»

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  • Increased Visibility of Targets Submerged in Scattering Opaque Media and Polarimetric Techniques

    Page(s): 2777 - 2781
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (327 KB) |  | HTML iconHTML  

    The novelty of this paper is indicated by a series of experimental measurements aimed at enhancing the detectability of targets immersed in scattered solutions. The experimental results clearly show that polarimetric images of superior quality can be obtained by doping the background surrounding the target with polar or high-dielectric molecules, yielding an enhanced contrast and specificity of the target. In addition, it is observed that degree of linear polarization (DOLP) images exhibit superior image characteristics with respect to total intensity (S0) images with the increase in the concentration of the optical scattering agents. View full abstract»

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  • Detection of Anomalous Behaviors in Networks From Traffic Measurements

    Page(s): 2782 - 2791
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1188 KB) |  | HTML iconHTML  

    Analysis and monitoring of traffic measurements can provide a useful tool for diagnostics, troubleshooting, and performance analysis in networks. This paper presents a method for traffic analysis based on the theory of extreme values. Numerical time series obtained from traffic measurements are processed to compute statistical indicators and analyze them to detect significant local features, which may point to some critical network behavior. View full abstract»

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  • A 1.2-V CMOS RC Oscillator for Capacitive and Resistive Sensor Applications

    Page(s): 2792 - 2800
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (913 KB) |  | HTML iconHTML  

    An accurate self-adjusting CMOS RC oscillator for capacitive and resistive sensor applications has been designed and manufactured. The oscillator operates with supply voltages from 1.2 to 3 V and achieves an internal accuracy of plusmn0.7% with a temperature range from -20degC to 60degC. The RC oscillator was fabricated in a 0.35-mum standard n-well CMOS process with threshold voltages of 0.5 and -0.65 V. Its design and operation are described, and results of measurements performed on the fabricated chips are presented. View full abstract»

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  • An Extended Wavelet Spectrum for Bearing Fault Diagnostics

    Page(s): 2801 - 2812
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (952 KB) |  | HTML iconHTML  

    Rolling-element bearings are widely used in various mechanical and electrical systems. A reliable online bearing fault-diagnostic technique is critically needed to prevent the system's performance degradation and malfunction. In this paper, an extended wavelet spectrum analysis technique is proposed for a more positive assessment of bearing health conditions. Two strategies have been suggested for different wavelet function implementation. Two statistical indexes are proposed to quantify the resulting wavelet (coefficient) functions. Based on the information provided by these indexes, the wavelet functions can be deployed more effectively over the designated frequency bands. An extended Shannon function is proposed to synthesize the wavelet coefficients over selected bandwidths to enhance feature characteristics. An averaged autocorrelation power spectrum is adopted to highlight bearing characteristics. The viability of the developed technique is verified by online experimental tests corresponding to different bearing conditions. View full abstract»

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  • Addressing Factors Affecting Fluorescent Signal Collection of a Multimode Photonic Crystal Fiber Fluorometer

    Page(s): 2813 - 2818
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    A multimode photonic crystal fiber (PCF) fluorometer interrogated by a spectrometer is investigated. By adding a glass tip at the end of the PCF, we found that this fluorometer significantly enhances the fluorescent light collection efficiency (CE). Factors associated with the CE and stray light rejection are addressed. The experimental study verifies the proposed PCF probe based on the consideration of solely meridian rays. However, our further study in this paper shows the significance of skew rays under total internal reflection (TIR), which in fact carry 53% of the total guidable fluorescent signal power and are blocked in our experiment. We highlight that this missing power is strongly associated with the numerical aperture (NA) of each optical component in the system and suggest further improvement on the components in the system. The proposed PCF fluorometer is particularly efficient and cost effective for an immersion medium with a high attenuation. View full abstract»

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  • The construction of random-fuzzy variables from the available relevant metrological information

    Page(s): 365 - 374
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (311 KB) |  | HTML iconHTML  

    Approaches other than the probabilistic approach recommended by the guide to the expression of uncertainty in measurement (GUM) have been proposed during the recent past for uncertainty expression and estimation. The approach based on random-fuzzy variables (RFVs) appears to be the most promising approach since it is based on the theory of evidence, which encompasses probability theory as a particular case. The correctness of the final uncertainty estimation quite directly depends on the way the RFVs are built, which depends on the available relevant metrological information. After briefly recalling the fundamentals of the RFV approach, this paper discusses how the available relevant information should be exploited to attain correct results. View full abstract»

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  • Detection and Characterization of Buried Macroscopic Cracks Inside Dielectric Materials by Microwave Techniques and Artificial Neural Networks

    Page(s): 2819 - 2826
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    The detection and characterization of macroscopic cracks inside dielectric materials is an important practical issue. Thus, there is a need to establish evaluation techniques, which can be used to characterize buried cracks; indeed, the knowledge of the geometrical configuration of a hidden crack is a key factor for fatigue crack engineering. Therefore, a microwave method for nondestructive characterization of macroscopic cracks inside dielectric materials is presented in this paper. This nondestructive and noncontact technique is based on the determination of the near-field reflection coefficient of an open-ended rectangular waveguide. The measurements are achieved by means of a microwave six-port-based system that operates at 35 GHz. We show that relatively small defects are detectable and demonstrate that the association of signal processing tools to this characterization method enables the retrieval of the crack profile in an acceptable manner. The reconstruction of a 1-D buried crack profile is performed by means of a multiple-multilayer-perceptron (MLP) approach. Several cases are investigated to demonstrate the capabilities of the method. View full abstract»

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  • Application of Segmented 2-D Probabilistic Occupancy Maps for Robot Sensing and Navigation

    Page(s): 2827 - 2837
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (899 KB) |  | HTML iconHTML  

    The concept of probabilistic occupancy maps was introduced by the end of the 1980s. Over the years, research has focused on the definition of the representation, the data fusion, and the generation of such occupancy models. However, few considerations have been given to processing occupancy maps as textured images to extract meaningful information that is required for robot navigation. This paper investigates the application of modern segmentation techniques over 2-D probabilistic occupancy maps that are encoded as textured images. Enhancements are proposed to a uniformity estimation technique based on local binary pattern and contrast (LBP/C) to achieve the robust segmentation of occupancy maps that typically result from range sensors with limited resolution. The enhanced LBP/C segmentation technique handles occupancy uncertainty and subdivides the space in regions that are characterized by three deterministic occupancy states, which are defined as free, unknown, and occupied. The approach is also extended to increase the number of classification levels, which provides the necessary flexibility to automatically select the regions that are characterized by a given range of occupancy states. The use of these extensions, along with the accuracy of the segmented 2-D occupancy maps, is first experimentally demonstrated on ground-based probabilistic grids for application in mobile robot navigation with collision avoidance. The potential of the proposed approach is also evaluated on aerial and satellite images for which it provides stable results and can find applications for unmanned aerial vehicle navigation. View full abstract»

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  • Flicker Measurement System for Wind Turbine Certification

    Page(s): 375 - 382
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (586 KB) |  | HTML iconHTML  

    There is currently a shortage of equipment specifically designed to measure and assess power quality in wind turbines in accordance with the International Electrotechnical Commission (IEC) 61400-21 standard. This deficiency negatively affects the work of companies involved in wind park installation facing the certification process. We have designed a system to measure and assess flicker in wind turbines in accordance with the standard. The system consists of two modules. The first module is a signal register to store the established voltage and current series as a function of the wind speed. The second module processes the stored series in accordance with the standard specification to precisely obtain the required flicker parameters of the wind turbine. Our system facilitates the certification process and is sufficiently flexible to cope with changing standards. View full abstract»

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  • An Adaptive BIST Design for Detecting Multiple Stuck-Open Faults in a CMOS Complex Cell

    Page(s): 2838 - 2845
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (331 KB) |  | HTML iconHTML  

    This paper describes a new adaptive built-in self-test (BIST) technique for detecting stuck-open faults in a CMOS complex cell. A test pattern generator (TPG) that adaptively generates a sequence of single-input-change test pairs based on the past responses of the circuit under test (CUT) is designed. Conventional TPGs produce a predefined sequence of test vectors. The novelty of the proposed approach lies in the fact that the test sequence (TS) generated by the TPG depends on the actual error produced by the CUT during testing. The BIST design is universal, i.e., independent of the structure or functionality of the CUT, and depends only on the number of inputs to the CUT. The length of the TS (|TS|) also depends on the error behavior; hence, it significantly reduces the average test application time. For an n-input CUT, it is shown that 4 les |TS | les 2n ldr2n. The design of the response analyzer is also simple. Barring a few exceptions, any irredundant multiple stuck-open faults, including those simultaneously occurring in both the n- and p- parts of a complex cell, are guaranteed to be detected using the proposed BIST scheme. View full abstract»

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  • Ultrasonic Thickness Measurement of Multilayered Aluminum Foam Precursor Material

    Page(s): 2846 - 2855
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1085 KB) |  | HTML iconHTML  

    Metallic foams are prospective materials for use in the aerospace and automotive industry for crash energy absorption safety parts or lightweight constructions. During manufacturing, artifacts in the foamable precursor material or material quality variations can influence the foam structure after the foaming process; thus, such a process requires quality control. The advantage of ultrasonic techniques is the possibility to perform noncontact and one-sided access measurements online. A three-layer system consisting of a layer of aluminum foam precursor sandwiched between two aluminum sheets has been investigated. The problems of ultrasonic nondestructive characterization of such materials are due to the very similar density and ultrasound velocity of the adjacent layers, which produce very weak reflections of ultrasonic waves, and the thin layers also give overlapped reflections in the time domain. The objective of this paper was to develop an ultrasonic technique that is suitable for measurement of the total thickness and the thickness of individual layers. The proposed technique is based on the identification of object parameters. The numerical iterative deconvolution technique was investigated, analyzed, and adapted to measure the thickness of individual layers with similar density and ultrasound velocity of the multilayered aluminum foam precursor material. Theoretical analysis and experimental investigations have shown that application of the proposed numerical iterative deconvolution enables the thickness measurement of individual layers with the expanded uncertainty of less than plusmn10 mum. View full abstract»

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Aims & Scope

Papers are sought that address innovative solutions to the development and use of electrical and electronic instruments and equipment to measure, monitor and/or record physical phenomena for the purpose of advancing measurement science, methods, functionality and applications.

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Meet Our Editors

Editor-in-Chief
Prof. Alessandro Ferrero
Dipartimento di Elettrotecnica
Piazza Leonardo da Vinci 32
Politecnico di Milano
Milano 20133 Italy
alessandro.ferrero@polimi.it
Phone: 39-02-2399-3751
Fax: 39-02-2399-3703