No. 1

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  Measurement in Biomedicine

   Pages

Ganesh R. Naik, Dinesh K. Kumar, Sridhar P. Arjunan:

Abstract: The presence of noise and cross-talk from closely located and simultaneously active muscles is exaggerated when the level of muscle contraction is very low. Due to this the current applications of surface electromyogram (sEMG) are infeasible and unreliable in pattern classification. This research reports a new technique of sEMG using Independent Component Analysis (ICA). The technique uses blind source separation (BSS) methods to classify the patterns of Myo-electrical signals during different Maximum Voluntary Contraction (MVCs) at different low level finger movements. The results of the experiments indicate that patterns using ICA of sEMG is a reliable (p<0.001) measure of strength of muscle contraction even when muscle activity is only 20% MVC. The authors propose that ICA is a useful indicator of muscle properties and is a useful indicator of the level of muscle activity.

Keywords:  surface electromyography, independent component analysis, blind source separation, gestures, maximum voluntary contractions, RMS, motor unit action potential

You Kok Yeow, Zulkifly Abbas, Kaida Khalid:

Application of Microwave Moisture Sensor for Determination of Oil Palm Fruit Ripeness

Abstract: This paper describes the development of a low cost coaxial moisture sensor for the determination of moisture content (30 % to 80 % wet-weight basis) of the oil palm fruits of various degree of fruit ripeness. The sensor operating between 1 GHz and 5 GHz was fabricated from an inexpensive 4.1 mm outer diameter SMA coaxial stub contact panel which is suitable for single fruit measurement. The measurement system consists of the sensor and a PC-controlled vector network analyzer (VNA). The actual moisture content was determined by standard oven drying method and compared with predicted value of fruit moisture content obtained using the studied sensor. The sensor was used to monitor fruit ripeness based on the measurement of the phase or magnitude of reflection coefficient and the dielectric measurement software was developed to control and acquire data from the VNA using Agilent VEE. This software was used to calculate the complex relative permittivity from the measured reflection coefficient between 1GHz and 5 GHz.

Keywords:  Vector network analyzer, moisture content, reflection coefficient, oil palm fruits, microwave sensors, dielectric constant

  Measurement of Physical Quantities

A. Abu_Al_Aish, M. Rehman, M. Z. Abdullah and A. H. Abu Hassan:

Microcontroller Based Capacitive Mass Measuring System

Abstract: The paper deals with a new design of a capacitive sensor developed for the accurate and precise measurement of mass. It employs a co-axial cylinder based capacitive sensor whose capacitance decreases linearly with mass, due to the shielding effect of the conducting shield, which moves between the stationary cylinders of the capacitor with the movement of the mass holder. An accurate capacitance to voltage converting system is used to detect the mass in terms of voltage. Linear relationship between mass and output signal is obtained with the help of microcontroller. The presented sensor has high order of linearity, flexibility in design and controllable damping. The overall size of the sensor may be reduced to very small values by this design. It is highly robust and may be attached to any complex system. For the spring, used in the system, mass sensor can measure up to 7 kg.

Keywords:  capacitive sensor; mass sensor; capacitance measuring system; microcontroller; spring

J. Song, T. Vorburger, R. Thompson, T. Renegar, A. Zheng, L. Ma, J. Yen, M. Ols:

Three Steps towards Metrological Traceability for Ballistics Signature Measurements

Abstract: The National Institute of Standards and Technology (NIST) in collaboration with the Bureau of Alcohol, Tobacco, Firearms and Explosives (ATF) has developed the Standard Reference Material (SRM) bullets and casings.  NIST and ATF are proposing to establish a National Ballistics Measurement Traceability and Quality System for ballistics signature measurements and correlations using these materials.  In this paper, three key steps towards metrological traceability for ballistics signature measurements are discussed that include: 1) Establishing a reference standard; 2) Establishing an unbroken chain of calibrations; and 3) Evaluating measurement uncertainty.

Keywords: traceability, forensic science, ballistics signature, standard reference material, standard bullet, standard casing

R. M. Radetic, D. R. Milivojevic, V. M. Despotovic:

Optimization of Measuring Current for Chopper Low Resistance Comparator

Abstract: The article describes systematic error analysis for realized chopper low-resistance comparator. The objective was to determine optimal working conditions, considering limited resolution (about 10 nV) and resistance variation due to self-heating caused by increase of measuring current. The analysis and performances of realized chopper low-resistance comparator prototype instrument confirmed the initial assumptions of applied principles. The error for 1 A measuring current is 1.15 ppm in the measuring range of 10 mW. It is possible to use the same principle for calculation of optimal measuring current and measurement error in other measurement ranges, as well.

Keywords:  low-resistance measurement, chopper comparator, error analysis

R. M. Radetic, D. R. Milivojevic, M. Pavlov:

The New Bridge Converter Control Method

Abstract: The article describes a new control method of transistor power bridge converter. It is a new one, because of some original solutions and its difference in comparison to existing methods. It’s irrelevant of load, similar to the “phase shifted” control method. It is easy to realize using ordinary electronic elements. A significant advantage of method is the possibility of permanent output current monitoring by measuring the voltage sag on a pair of transistors. That allows a very efficient current protection.

Keywords:  control method, bridge converter, PWM

  Measurement in Biomedicine

S. Štolc, I. Bajla:

On the Optimum Architecture of the Biologically Inspired Hierarchical Temporal Memory Model Applied to the Hand-Written Digit Recognition        Invited paper

Abstract: In the paper we describe basic functions of the Hierarchical Temporal Memory (HTM) network based on a novel biologically inspired model of the large-scale structure of the mammalian neocortex.The focus of this paper is in a systematic exploration of possibilities how to optimize important controlling parameters of the HTM model applied to the classification of hand-written digits from the USPS database. The statistical properties of this database are analyzed using the permutation test which employs a randomization distribution of the training and testing data. Based on a notion of the homogeneous usage of input image pixels, a methodology of the HTM parameter optimization is proposed. In order to study effects of two substantial parameters of the architecture: the patch size and the overlap in more details, we have restricted ourselves to the single-level HTM networks. A novel method for construction of the training sequences by ordering series of the static images is developed. A novel method for estimation of the parameter maxDist based on the box counting method is proposed. The parameter sigma of the inference Gaussian is optimized on the basis of the maximization of the belief distribution entropy. Both optimization algorithms can be equally applied to the multi-level HTM networks as well. The influences of the parameters transitionMemory and requestedGroupCount on the HTM network performance have been explored. Altogether, we have investigated 2736 different HTM network configurations. The obtained classification accuracy results have been benchmarked with the published results of several conventional classifiers.

Keywords:  hierarchical temporal memory (HTM); optimum network architecture, visual pattern recognition, USPS hand-written digits

  Measurement of Physical Quantities

M. Jurčević, H. Hegeduš, M. Golub:

Generic System for Remote Testing and Calibration of Measuring Instruments: Security Architecture

Abstract: Testing and calibration of laboratory instruments and reference standards is a routine activity and is a resource and time consuming process. Since many of the modern instruments include some communication interfaces, it is possible to create a remote calibration system. This approach addresses a wide range of possible applications and permits to drive a number of different devices. On the other hand, remote calibration process involves a number of security issues due to recommendations specified in standard ISO/IEC 17025, since it is not under total control of the calibration laboratory personnel who will sign the calibration certificate. This approach implies that the traceability and integrity of the calibration process directly depends on the collected measurement data. The reliable and secure remote control and monitoring of instruments is a crucial aspect of internet-enabled calibration procedure.

Keywords:   internet-enabled testing and calibration, travelling standard, hardware security module (HSM), ISO/IEC 17025

K. Hariharan, P. Vasanthakumar, G. Varun, V. Abhaikumar:

A Method for ADC Error Testing and its Compensation in Ratiometric Measurements

Abstract: Errors induced due to ratiometric measurements are discussed and a simplified compensation method to reduce the various static errors of ADC, voltage reference errors in ratiometry and resistance mismatch errors is proposed. Curve fitting is done for the error samples and the system is modelled in comparison to an ideal system. Static errors and other ratiometric errors, thus modelled are derived into a corrective equation in comparison with an errorless system. Implementation of the proposed method is discussed for a resistance measurement system and analyzed. This paper also discusses the usage of the proposed system with successive approximation ADCs for ratiometric measurement operations against the conventional requirement dual slope ADCs for the same.

Keywords:  ratio-metric measurements, curve fitting, ADC error testing, error compensation

E. Kuvaldin:

Counting Method for Measuring and Linearity Checking Photometry Devices

Abstract: The possibility of calibration and linearity check of optical detectors in a wide dynamic range by method of counting separate parts of energy is investigated. Counting method permits nonselective energy change  of measuring optical pulse more then 105 times. A construction of working source of radiation with GaAs LED is described. Results of experimental investigation are presented.

Keywords:  optical measurement, check linearity, energy meter, calibration, pulse count

A. Kavitha, C. M. Sujatha and S. Ramakrishnan:

Prediction of Spirometric Forced Expiratory Volume (FEV1)  Data Using Support Vector Regression

Abstract: In this work, prediction of forced expiratory volume in 1 second (FEV1) in pulmonary function test is carried out using the spirometer and support vector regression analysis. Pulmonary function data are measured with flow volume spirometer from volunteers (N=175) using a standard data acquisition protocol. The acquired data are then used to predict FEV1. Support vector machines with polynomial kernel function with four different orders were employed to predict the values of FEV1. The performance is evaluated by computing the average prediction accuracy for normal and abnormal cases. Results show that support vector machines are capable of predicting FEV1 in both normal and abnormal cases and the average prediction accuracy for normal subjects was higher than that of abnormal subjects. Accuracy in prediction was found to be high for a regularization constant of C=10. Since FEV1 is the most significant parameter in the analysis of spirometric data, it appears that this method of assessment is useful in diagnosing the pulmonary abnormalities with incomplete data and data with poor recording.

Keywords:  spirometry, forced expiratory maneuver, support vector regression

S. Kosarevsky,  V. Latypov:

Inertia Compensation While Scanning Screw Threads on Coordinate Measuring Machines

Abstract: Usage of scanning coordinate-measuring machines for inspection of screw threads has become a common practice nowadays. Compared to touch trigger probing, scanning capabilities allow to speed up the measuring process while still maintaining high accuracy. However, in some cases accuracy drastically depends on the scanning speed. In this paper a compensation method is proposed allowing to reduce the influence of inertia of the probing system while scanning screw threads on coordinate-measuring machines.

Keywords:  scanning, CMM, accuracy, screw thread

  Measurement in Biomedicine

J. Přibil, A. Přibilová:

An Experiment with Evaluation of Emotional Speech Conversion by Spectrograms

Abstract:The spectrogram is a useful tool for visual quality comparison of different types of emotional synthetic speech. This paper is focused on application of this method to evaluation of sentences after spectral and prosodic modifications for emotional speech conversion. Performed experiments with spectrogram evaluation for several male and female speakers and four emotional states (joy, sadness, anger, neutral state) are also described.

K. Sapozhnikova, R. Taymanov:

Improvement of Traceability of Widely-Defined Measurements in the Field of Humanities

Abstract: In the last decades, a tendency to extend the domain of “fuzzy” measurements of multiparametric quantities to the field of humanities has been observed. In the measurement process, the “fuzzy” measurements should meet the requirements of metrological traceability. The paper deals with the approach proposed for developing a measurement model of “fuzzy” measurements. The approach suggested is illustrated by an example of a model for measuring the emotions contained in musical fragments. The model is based on the hypothesis that permits to explain the origination of emotions in the evolution process.

  Measurement of Physical Quantities

D. Sumina, A. Šala, R. Malarić:

Determination of Load Angle for Salient-pole Synchronous Machine

Abstract: This paper presents two methods for load angle determination for salient-pole synchronous generator. The first method uses optical encoder to detect the rotor position. In some cases the end of the rotor shaft is not free to be used and mounting of an encoder is impossible. Therefore, the second method proposes estimation of the load angle based on the measured electrical values that have been already used in excitation control system of the synchronous generator. Estimation method uses corresponding voltage-current vector diagram and parameters of the synchronous generator, transformer and transmission lines. Both methods were experimentally verified on the digital control system and synchronous generator connected to power system. The estimation and measured results were compared. The accuracy of load angle estimation method depends on voltage and current measurement accuracy as well as generator, transformer and transmission line parameter accuracy. The estimation method gives satisfactory accuracy for load angles less than 120º el. Thus, it can be applied in excitation control system to provide stable work of synchronous generator in under-excitation operating area.

I. Frollo,  P. Andris, J. Přibil, L. Vojtíšek, T. Dermek, L. Valkovič:

Measurement and Imaging of Planar Electromagnetic Phantoms Based on NMR Imaging Methods

Abstract: Planar electromagnetic phantom design for measurement and imaging using NMR has been performed. Electromagnetic phantom computation and testing on a NMR 0.178 Tesla Esaote Opera imager were accomplished. The classical geometrical and chemical phantoms are generally used for testing of NMR imaging systems. They are simple cylindrical or rectangular objects with different dimensions and shapes with holes filled with specially prepared water solutions. In our experiments a homogeneous phantom (reference medium) - a container filled with water - was used. The resultant image represents the magnetic field distribution in the homogeneous phantom.  An image acquired by this method is actually a projection of the sample properties onto the homogeneous phantom. The goal of the paper is to map and image the magnetic field deformation using NMR imaging methods. We are using a double slender rectangular vessel with constant thickness filled with specially prepared water solution in our experiments. For detection a carefully tailored gradient-echo imaging method, susceptible to magnetic field homogeneity, was used.

V.P. Lukin, N.N. Botygina, O.N. Emaleev, P.A. Konyaev:

Wavefront sensors for adaptive optical systems

Abstract: A high precision Shack-Hartmann wavefront (WF) sensor has been developed on the basis of a low-aperture off-axis diffraction lens array. The device is capable of measuring WF slopes at array sub-apertures of 640х640 mm in size with an error not exceeding 4.80 arcsec (0.15 pixel), which corresponds to the standard deviation equal to 0.017 λ at the reconstructed WF with wavelength λ. Also the modification of this sensor for adaptive system of solar telescope using extended scenes as tracking objects, such as sunspot, pores, solar granulation and limb, is presented. The software package developed for the proposed WF sensors includes three algorithms of local WF slope estimation (modified centroids, normalized cross-correlation and fast Fourier-demodulation), as well as three methods of WF reconstruction (modal Zernike polynomial expansion, deformable mirror response function expansion and phase unwrapping), that can be selected during operation with accordance to the application.

V.E. Privalov, V.G. Shemanin, E.I.Voronina:

Iodine Molecules Differential Absorption Cross section Lidar Studies

Abstract: Lidar monitoring of the gaseous molecules in atmosphere can be used for concentration measurements of the toxic pollutants in air of the urban and industrial regions. Such a concentration study in the multi-components gaseous mixture by lidar technique is a complex problem in atmospheric pollution monitoring. The differential absorption lidar (DA-lidar) is the most preferable for the detection of iodine molecules at very low concentration levels. The iodine molecules absorption cross section in the laboratory lidar studies and lidar equation simulation in this lidar variant corresponds with earlier data.

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