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Instrumentation and Measurement Technology Conference, 1998. IMTC/98. Conference Proceedings. IEEE

Date 18-21 May 1998

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  • Imtc/98 [front matter]

    Publication Year: 1998 , Page(s): i - xxiv
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    Freely Available from IEEE
  • Author's index

    Publication Year: 1998 , Page(s): xxix - xxxv
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  • Multiwinding transformers: a successive refinement method to characterize a general equivalent circuit

    Publication Year: 1998 , Page(s): 717 - 722 vol.2
    Cited by:  Papers (2)
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    A lumped component equivalent circuit has been developed by our team to model the linear electrical behaviour of any two winding transformer. Its topology is independent of sizes and technology and a general method of characterization, based exclusively on external impedance measurements, has been presented. Unfortunately, when some key frequencies are out of the range of the measuring apparatus, many of its components remain unevaluated. Owing to a new understanding of magnetic and electrostatic coupling, a several step approach is presented. At each step a more accurate circuit proven to be effective in electronic simulation, is fully characterized. This method suits whatever the number of windings and experimental data will be presented for two and three winding transformers View full abstract»

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  • The measurement system for the automatic determination of characteristic points of solid materials

    Publication Year: 1998 , Page(s): 1116 - 1120 vol.2
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    New method for the automatic determination of characteristic points of phase transitions of solid materials like sintering, softening, melting and flow points is presented. This method is based on the examination of the emissivity variation of the sample surface. The special system for the continuous observation and analysis of these variation was built. This system is equipped with the vertical tube furnace, radiation pyrometer, two thermocouples, computer PC with A/D converter and control and analysis software working in Windows 95. Important part of this work is connected with the data measurement correction. A special digital filtering algorithm based upon piece-wise second order polynomial approximation is applied View full abstract»

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  • An adaptive window function method for power measurement

    Publication Year: 1998 , Page(s): 785 - 790 vol.2
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    An adaptive window function for distorted power measurement is introduced in this paper. It can automatically provide the optimal window function according to the actual measured signal. Thus, the applied window function is always optimal due to the advantageous zeros of its frequency response corresponding to undesired spectrum components of the measured signal. As a result, the harmful truncation errors of asynchronous sampling and the influence of interharmonics in the measured signal spectrum can be totally eliminated. The correctness and applicability of the proposed method have been verified both theoretically and by extensive simulations View full abstract»

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  • 3-D temperature distribution in ultrasound interstitial heating with three applicator array

    Publication Year: 1998 , Page(s): 858 - 862 vol.2
    Cited by:  Papers (4)
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    We present finite element simulations of 3-D temperature pattern in ultrasound interstitial heating of the brain tissue. Instrumentation to produce the heating is a three-waveguide-applicator array. For asymmetric boundary condition, i.e., heating of malignant tissue to the brain side, our methodology helps to find optimum placement of the array. It enables also calculation of individual power at each applicator resulting in improved heating pattern and reduced heat toxicity View full abstract»

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  • A visual feedback system for micromanipulation with stereoscopic microscope

    Publication Year: 1998 , Page(s): 1127 - 1132 vol.2
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    A stereoscopic microscope is widely used in a micromanipulation such as to operate genes and to inspect integration circuits. As in these tasks the micromanipulation is handled and makes too heavy burden to operators, it is desirable to perform the micromanipulation automatically. In this paper, we propose a visual feedback system for micromanipulation with stereoscopic microscope. This system takes less time to control the manipulator by reducing searching area to detect an object View full abstract»

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  • Metrological characterization of a novel absolute distance meter based on dispersive comb-spectrum interferometry

    Publication Year: 1998 , Page(s): 1137 - 1140 vol.2
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    The paper reports results of an investigation on the main measurement uncertainty sources in a novel distance meter based on dispersive comb-spectrum interferometry. The light source is a commercial laser diode operating at 670 nm driven ender the threshold condition, and emitting a beam with a comb-shaped spectrum. Sensitivity of the measurement to the operating conditions has been evaluated. Results from an experimental activity aimed at characterizing the laser and to measure the performance of a prototype implementation are also presented. The system is suitable to perform unambiguous non-incremental distance measurements over a range of 0.8 mm with a total uncertainty of about 1.5 μm View full abstract»

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  • Nonlinear averagings and overlapping techniques for spectral analysis of noisy signals

    Publication Year: 1998 , Page(s): 909 - 914 vol.2
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    The authors propose a new method for accurate spectral estimation of noisy signals. The major drawback caused by trade-off between spectral resolution and variance is examined. The main aim of the paper is to show how the accuracy of periodogram estimation can be improved by adopting nonlinear averaging techniques of partially overlapped time slice of data samples. Also, the effects of the taper functions and the percentage overlap both on the computational cost and the improvements achievable are investigated. The derived expressions for the bias and variance point out the better performance of this method with respect to previous ones. Finally, the experimental validations of the results are shown View full abstract»

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  • Multi-functional sensing for high-sensitivity detection of initial state of iron rust

    Publication Year: 1998 , Page(s): 1145 - 1148 vol.2
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    Some nondestructive diagnostic methods including various types of corrosion sensor have been investigated. Under these conditions, a new structure of the sensor which has a pair of electrodes and magneto-supply is proposed. Two different states of the sensor, called a surface mode and a penetration mode, are realized by changing the direction of the magnetic field. For the initial state of iron rust, its thickness is sensitively detected in the surface mode, and precisely in the penetration mode. As the result, our proposed sensor can act as a multi-functional-sensing device useful for detecting the initial stale of iron rust View full abstract»

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  • Reliable LDA-spectra by resampling and ARMA-modeling

    Publication Year: 1998 , Page(s): 1290 - 1295 vol.2
    Cited by:  Papers (2)
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    Laser-Doppler Anemometry (LDA) is used to measure the velocity of gases and liquids with observations irregularly spaced in time. Linear interpolation of the data followed by equidistant resampling turns out to be better than slotting techniques. After resampling, two ways of spectral estimation are compared. The estimates are a windowed periodogram and a time series model with an ARMA process whose orders are automatically selected from the data with an objective statistical criterion. Typically, the ARMA spectrum is better than the best of all windowed periodograms View full abstract»

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  • A probabilistic approach to the threshold error reduction theory in bistable measurement devices

    Publication Year: 1998 , Page(s): 1307 - 1312 vol.2
    Cited by:  Papers (4)
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    The notion of noise activated system has been well known since the 1950s. A lot of natural phenomena have been investigated by means of this theory. The improvement of several system performances have been performed as well. One of the most important techniques based on noisy forcing signal is the well known dithering. In particular it has been used for improving the performances in A/D converters. Recently the stochastic resonance phenomenon (SR) has been introduced as an innovative approach for both understanding the behaviour and improving the performances of bistable systems. In this work a new approach to the SR theory is reported in order to investigate the influence of forcing signal parameters on the persistence of the SR condition. Both theoretical results and simulations have been carried out in order to emphasise the suitability of the proposed methodology View full abstract»

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  • Characterization of a magnetic field sensor based on torque measuring

    Publication Year: 1998 , Page(s): 1033 - 1036 vol.2
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    A sensor for low frequency measurements of the magnetic field is presented in the paper. It is based on the measurements of an electromagnetic torque. An output directly proportional to the unknown magnetic field is produced, the method has the main advantage of avoiding the drifts present in the integration of signals from inductive sensors. The design and construction criteria, aiming at an uncertainty of few milliteslas in field measuring, are described. The analysis of the sensor linearity is presented in the paper together with the test rig, able to guarantee well reproducible conditions. The dynamic behavior of the torque based sensor is considered. It is studied either on the basis of the coil and load cell characteristics or analyzing the response to an applied known electromagnetic torque View full abstract»

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  • A fine control of the air-to-fuel ratio with recurrent neural networks

    Publication Year: 1998 , Page(s): 924 - 929 vol.2
    Cited by:  Papers (3)
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    A fine control of the air-to-fuel ratio is a fundamental issue to minimise exhaust emissions in automotive fuel injection systems. Traditional approaches have limited effectiveness since the air-to-fuel ratio is sensitive to small engine perturbations, some parts of the combustion process are unknown and some others are nonlinear. In this paper we introduce a direct neural-based control scheme which results in a performance obtainable with more classic approaches based on transient fuel film compensation View full abstract»

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  • Measuring active power, voltage and current using slow A/D converters

    Publication Year: 1998 , Page(s): 732 - 737 vol.2
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    A new design of a digital measurement system based on the use of very slow highly precise and cheap A/D converters (dual slope) is described in this paper. Measurements of voltage and current are performed more than once in a period, so the measured value is reconstructed after n periods. Measurements performed on the electric utilities in Yugoslavia indicate that the voltage waveform remains unchanged while the required accuracy is maintained View full abstract»

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  • Silver-stained “comets” for the detection of radiation-induced apoptosis: automated assay

    Publication Year: 1998 , Page(s): 868 - 873 vol.2
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    This paper reviews the development of a bioassay that uses apoptosis (a form of cell death) to directly measure the response of cells to a physical or chemical insult. The assay described here is in mid-phase of development and has been applied to various cell lines isolated from humans and mice. Under the assay conditions, apoptotic cells present a isignaturei, or morphology, distinct from other cells. The exposure of cells to ionising radiation, UV light or some chemicals, produces a dose-dependent increase in the apoptotic fraction. The dose response is linear up to about 1 Gy of ionising radiation. A preparation technique for the cells is used that produces a permanent record of the experiment. With automation, the statistical power of the assay is substantial since there are potentially 105 cells that can be examined at each data point. A prototype system is described, it consists of a bright-field microscope and a computer controlled microscope stage integrated with preliminary image analysis software. Trials indicate that 200-400 cells per minute can be assessed for isignaturesi characteristic of apoptotic and unaffected has also begun to determine if the assay can be used to predict the relative radiosensitivities of normal and tumour cells, information that could be used to assist in the planning of dosing schedules for radiotherapy View full abstract»

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  • Central heating control: a new technique to gauge room temperature

    Publication Year: 1998 , Page(s): 1079 - 1082 vol.2
    Cited by:  Papers (3)  |  Patents (2)
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    The project criteria and common evolution in design and restructuring central heating systems are leading to the complete elimination and substitution of the old, enormous central heating boilers (only one of them was planned to heat up to 40 flats), for one-family stand-alone systems. This tendency-encouraged by the Italian law-has the favorable effect to install new, well-operating devices in the place of the old ones; at the same time it allows the user to regulate the heating according to his own requirements and finally he will pay only his own gas bill: not more, not less. This new system is designed to operate on a central heating system (no matter what size), but takes its maximum advantage when implemented in district heating: the incoming constant-flow hot water is piped in a heat exchanger. Water temperature at the flowing in and out is gauged by two sensors, in order to obtain a reliable value for the power consumption; two other sensors are employed to gauge room temperature. A local unit processes signals and data, and communicates by a serial bus (only one line serves up to 64 remote units) with a remote computer. This last one acquires in real time all temperature data, compare them with data fixed by users and calculates power consumption. Each user can at any moment choose and request one of the eight heating programs, from maximum economy to maximum comfort View full abstract»

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  • Waveform missing mechanisms and a countermeasure in a random sampling system

    Publication Year: 1998 , Page(s): 1319 - 1324 vol.2
    Cited by:  Papers (3)
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    This paper reports on a newly revealed waveform missing mechanism and a rational countermeasure in a random sampling system. Random sampling is an equivalent sampling technique which measures waveforms using a finer time resolution compared to the sampling period. Random sampling is usually applied for digital storage oscilloscopes (DSOs). Its design does not require delay lines for introducing the time shift for the measured signals, and theoretically, it is able to measure very-wide-band signals. However, partial waveform missing phenomenon will occur if interference between the trigger signals and hold-off (HO=trigger-enable) signals exists. One of the mechanisms already reported for the phenomenon is where the trigger periods are shorter than those of the sampling periods. Some dithers were added to hold-off signals to eliminate the interference. We call this method the random hold-off method (RHM). In this paper, we introduce the second mechanism where the trigger signals are not evenly divided by hold-off signals. Unexpectedly, RHM has a good effect on the second mechanism. However, we propose a rational countermeasure with no dither to avoid both mechanisms. Our proposed countermeasure controls the timing of the hold-off signals using the data which was measured during a series of acquisitions. We call it the constant hold-off method (CHM). CHM makes it possible to design a low-display-noise and wide-band DSOs because dither produces intermodulation. In a simulation, the waveform acquisition time of CHM is about two-thirds that of RHM View full abstract»

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  • Fiber-optic sensor systems for absolute measurements

    Publication Year: 1998 , Page(s): 942 - 947 vol.2
    Cited by:  Papers (1)
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    In this review presentation we provide a short introduction to fiber-optic sensor technology, a quickly emerging novel industrial application area of photonics, different from fiber-optic communications. Fundamental sensor concepts, sensor classification, sensor components and several representative examples of industrial sensor systems will be presented with special focus on sensors and sensor systems developed for absolute measurements in the area of engineering mechanics. Several specific topologies of fiber-optic absolute pressure transducers developed recently at the Laboratory of Industrial Optoelectronics (LIO) at UQAH to meet requirements for use in general purpose pressure measurements, and for load distribution measurements in large engineering structures will also be presented View full abstract»

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  • A silicon wafer dissolved vibrating gyroscope

    Publication Year: 1998 , Page(s): 1133 - 1136 vol.2
    Cited by:  Patents (1)
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    Since micromachining technology has raised the prospect of batch fabrication high performance sensors with low cost and small size, many researchers have investigated the micromachined gyroscope which is expected to rapidly grow in the automotive and consumer market. This paper proposes a vibrating wheel gyroscope developed by a bulk silicon dissolved wafer process. The dimension of movable elements is designed as φ 1.2 mm×0.015 mm and the FEM simulation results are provided. The fabrication sequence is introduced and the key technique of high aspect ratio trenches etching is introduced. Primary test results show that this kind of micromachined gyroscope would satisfy the requirements of trade market View full abstract»

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  • Identification of a two input two output distillation column using noninteracting multifrequency ternary and quaternary signals

    Publication Year: 1998 , Page(s): 1011 - 1016 vol.2
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    This paper presents a new approach to the system identification of a two input multivariable system. In a similar manner to that used for the single-input/single-output system, the multi-input multi-output system response may be obtained directly from measured input output frequency responses. An investigation of compact multifrequency data measurement signals, which have been extensively catalogued by the authors, has provided compact multifrequency ternary and quaternary input signals that have uncorrelated spectra. They are powerful multisymbol, multilevel computer generated measurement signals whose signal power is concentrated in either two or three dominant harmonics. As the signals, which are given in this paper, have six, seven or eight symbols in their measurement codes, it is ensured that both the computation time for the frequency estimates and the experimental time are minimized. Two multifrequency quaternary signals with uncorrelated spectra are used to identify a simulated distillation column. It is shown that the cross coupling terms between the measurement channels may be removed by these digital measurement signals with the same number of symbols but different measurement codes View full abstract»

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  • Ultra low noise, current to voltage converter with offset compensation independent of the source impedance

    Publication Year: 1998 , Page(s): 752 - 754 vol.2
    Cited by:  Papers (4)
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    A new version of a low-noise, high gain transimpedance amplifier, operating in the frequency range from DC to KHz, is described. The new version of the instrument, thanks to a completely differential architecture, is capable to give the same stability without controlling the temperature of the input stage, as in the previous one. A more sophisticated circuitry for offset nulling allows to null contemporaneously both voltage and current input offset sources. A further improvement of the performance, as far as low frequency noise is concerned, has been obtained. In fact, for instance, the input equivalent current noise is 5.2 fA/√Hz between 10 mHz and 2 Hz View full abstract»

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  • Current measurement in electrical discharges in air gaps for conducted noise estimation

    Publication Year: 1998 , Page(s): 749 - 751 vol.2
    Cited by:  Papers (5)
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    In this paper current rising time and power spectral density in electrical discharges in overvoltaged air gaps with different electrode geometries are investigated in order to perform a preliminary study on the characteristics of the conducted electrical disturbances. The main objective of this work is to study spontaneously generated sparks, without using any UV or similar pre-ionization methods, in order to reproduce as close as possible real life electrical or electrostatic discharges. An experimental set up was implemented and highly reproducible discharge currents waveforms were obtained View full abstract»

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  • A CMOS IC for portable EEG acquisition systems

    Publication Year: 1998 , Page(s): 1406 - 1410 vol.2
    Cited by:  Papers (6)
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    This paper presents a monolithic low-power, low-noise analog front-end electroencephalogram (EEG) acquisition system. It draws only 500 μA from a standard 9 V battery, making it suitable for use in portable systems. Although fabricated in a standard CMOS technology, using current feedback techniques it achieves a CMRR of 100 dB while the total input noise referred to input is kept as low as 1.5 μV (RMS) View full abstract»

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  • Thermal performance of plastic-encapsulated and hermetically sealed components for automotive applications

    Publication Year: 1998 , Page(s): 1185 - 1188 vol.2
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    In automotive applications reliability and lifetime of electronic components are mainly influenced by aging processes related to superposing effects of mechanical vibrations, thermomechanically induced stress and thermal load. Two of these factors can be minimized by optimizing the component's thermal design. In this work measured and simulated thermal qualities of plastic-encapsulated and ceramic packages are compared. The experimental test procedure and main features of a new thermal simulation tool especially designed for the prediction of thermal characteristics of mono-chip and multi-chip components are discussed. Although, the thermal conductivity of ceramic is high compared to plastic moldings our results clearly show that plastic packages can compete with their ceramic counterparts View full abstract»

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