No. 1

 Theoretical Problems of Measurement

    Pages

S.V. Kosarevsky, V.N. Latypov:

Practical Procedure for Position Tolerance Uncertainty Determination via Monte-Carlo Error Propagation

Abstract: Determination of realistic uncertainty values in coordinate metrology is a challenging task due to the complexity of the implementation of numerical algorithms involved. Monte-Carlo error propagation is used to estimate the uncertainty of a position tolerance using least-squares criterion. In this paper all the required steps are sequentially performed using a number real-world datasets. Since no reference data sets are available for position tolerance evaluation hence drawings and numerical values of such data sets are proposed.

Keywords:  Uncertainty evaluation, propagation of distributions, Monte-Carlo simulation, position tolerance

  Measurement of Physical Quantities

N. Angkawisittpan, T. Manasri:

Determination of Sugar Content in Sugar Solutions using Interdigital Capacitor Sensor

Abstract: A novel low-cost electronic tongue system for sugar content determination in sugar solutions is proposed. The system consists of a sine wave generator, a resistor, and an interdigital capacitor sensor forming a first-order electronic high-pass filter circuit. The interdigital capacitor sensor has the planar interdigital structure and the consecutive fingers are connected to positive and negative electrodes. The system has been assembled and the experiments were conducted. The experimental results show that the proposed system has a great potential to determine the sugar content in sugar solutions. It also provides an opportunity for the development of a microcontroller-based low-cost sensing system as an electronic tongue system.

Keywords:  Interdigital capacitor, high-pass filter, relative permittivity, electronic tongue, sugar concentration

F. Tootoonchian, K. Abbaszadeh, M. Ardebili:

A New Technique for Analysis of Static Eccentricity in Axial Flux Resolver

Abstract: Resolvers have been widely used in motion control systems as position sensors. This paper deals with the analysis of Axial Flux Resolvers. Axial flux resolvers are a group of resolvers which can be used in high performance servomechanisms. The accuracy of resolver detected position is affected by errors. Some of these errors are caused by speed fluctuations, permeance ripples, unbalanced voltages, and eccentricity between rotor and stator. Among these errors the static eccentricity (SE) is not corrected electronically. In this paper, the eccentric resolver is modeled analytically based on d-q synchronous rotating coordinate system with different Ld and Lq values and then, the static eccentricity effect based on the developed model is studied. A novel algorithm is proposed for suppressing the eccentricity error. This method is based on analytical model and modern control fundamentals. In a comparison, simulation and experimental results show good agreement. Finally, the effect of air gap length, pole number and excitation voltage on position error of eccentric AFR is investigated, practically.

Keywords:  Position sensor, axial flux resolver, static eccentricity, dynamic model, state feedback, pole placement

Measurement in Biomedicine

C. W. Hsieh, C. Y. Chen, T. L. Jong, T. C. Liu, C. H. Chiu:

Automatic Segmentation of Phalanx and Epiphyseal/Metaphyseal Region by Gamma Parameter Enhancement Algorithm

Abstract: The performance of bone age assessment is highly correlated with the extraction of bony tissue from soft tissues, and the key problem is how to successfully separate epiphyseal/metaphyseal region of interests (EMROIs) from the background and soft tissue. In our experiment, a series of image preprocessing procedures are used to exclude the background and locate the EMROIs of left-hand radiographs. Subsequently, automatic gamma parameter enhancement is applied to test the two segmentation methods (adaptive two-means clustering algorithm and gradient vector flow snake) among children of different age (the age from 2 to 16 years for 80 girls and boys). Four error measurements of misclassification error, relative foreground area error, modified Hausdorff distances, and edge mismatch, are included to evaluate the segmentation performance. The result shows that the two segmentation algorithms are corresponding to different ranges of optimal gamma parameters. Furthermore, the margin of EMROIs can be obtained more precisely by developing an automatic bone age assessment method with the gamma parameter enhancement.

Keywords:  Bone age, Epiphyseal/metaphyseal, Segmentation, Gamma parameter enhancement, Adaptive two-means clustering

M. S. Hussain, Md. Mamun:

Effectiveness of the Wavelet Transform on the Surface EMG to Understand the Muscle Fatigue During Walk

Abstract: Muscle fatigue is the decline in ability of a muscle to create force. Electromyography (EMG) is a medical technique for measuring muscle response to nervous stimulation. During a sustained muscle contraction, the power spectrum of the EMG shifts towards lower frequencies. These effects are due to muscle fatigue. Muscle fatigue is often a result of unhealthy work practice. In this research, the effectiveness of the wavelet transform applied to the surface EMG (SEMG) signal as a means of understanding muscle fatigue during walk is presented. Power spectrum and bispectrum analysis on the EMG signal getting from right rectus femoris muscle is executed utilizing various wavelet functions (WFs). It is possible to recognize muscle fatigue appreciably with the proper choice of the WF. The outcome proves that the most momentous changes in the EMG power spectrum are symbolized by WF Daubechies45. Moreover, this research has compared bispectrum properties to the other WFs. To determine muscle fatigue during gait, Daubechies45 is used in this research to analyze the SEMG signal.

Keywords:  Electromyography, surface electromyography, wavelet, bispectrum

A. Rouane, D. Kourtiche:

Characterization of Microwave Antennas for Intracardiac Ablation Frequencies 915 and 2450 MHz

Abstract: This paper studies the microwave antenna characterization in intracardiac ablation for frequencies 915 and 2450 MHz. The theoretical study is validated by experimental measurements in vitro on electromagnetic phantom muscle tissue. The Specific Absorbed Rate (SAR) measurement setup is described. Two types of antennas have been designed, implemented and used, a monopoly antenna and a helical antenna. The Specific Absorbed Rate (SAR) and the measured reflection coefficient (S11) were obtained for antennas for the two frequencies. We show that each frequency can be adapted to a region where the ablation is necessary. According to the doctors, the goal is to have a lesion on the surface as the atria or in depth.

Keywords:  Cardiac ablation, microwave antenna, Specific Absorbed Rate, reflection coefficient

 Top ↑  

 Theoretical Problems of Measurement

Fumin Zhang, Xinghua Qu:

Fusion Estimation of Point Sets from Multiple Stations of Spherical Coordinate Instruments Utilizing Uncertainty Estimation Based on Monte Carlo

Abstract:  Multiple instrument stations, based on spherical coordinate measurements, are often used in the measurement of large objects. A data fusion method is proposed to derive optimal estimations of the positions of the object features, measured by more than one device. First, each device has a dedicated coordinate system that is linked together through the measurement of common points. Second, the weighted mean coordinates are derived. The covariance matrix of the sensory, covering of the radial distance and the angles, is propagated to get a weight matrix. Third, a nonlinear function is minimized to determine the optimized coordinate of the points. Monte Carlo error propagation is utilized to estimate the uncertainty of the fusion points. Simulation of the fusion algorithms is performed using laser tracking and laser radar. The fusion algorithm experiments are performed using two laser tracking stations. Simulation and experiments prove that the fusion method improves the precision of the measurements of an object’s location, due to incorporating the degree of uncertainty for each measurement point.

 Keywords:  Large volume metrology, multiple-station data fusion, uncertainty, Monte Carlo, laser tracker

Measurement in Biomedicine

Naga Rajesh A., Chandralingam S., Anjaneyulu T., Satyanarayana K.:

Denoising EOG Signal using Stationary Wavelet Transform

Abstract:  Eye movements are critical signs of the neurological disorders and they can be acquired by EOG. The EOG signal is electrical signal generated due to eye ball movements and is contaminated with brain signals and power line while recording. As the EOG signal is a non-stationary signal, it can be denoised by wavelet transformation techniques. The present work covers denoising of noisy EOG signal using Stationary Wavelet Transform (SWT), which was done with all suitable wavelets that are morphologically similar to an EOG signal by applying both Soft and Hard Thresholding methods. An EOG signal was simulated and added with noise to obtain noisy EOG signal. The wavelet analysis of the simulated noisy EOG signal reveals that the Biorthogonal 3.3 wavelet is the best wavelet to denoise by using SWT technique, wherein the yield achieved was good with Signal to Noise Ratio of 36.5882 dB and minimum Mean Square Error of 0.383313 for quality diagnosis.

Keywords:  EOG signal, Wavelet transform, denoising, thresholding, biorthogonal wavelet

M. A. Hasan, M. B. I. Reaz:

Hardware Prototyping of Neural Network based Fetal Electrocardiogram Extraction

Abstract:  The aim of this paper is to model the algorithm for Fetal ECG (FECG) extraction from composite abdominal ECG (AECG) using VHDL (Very High Speed Integrated Circuit Hardware Description Language) for FPGA (Field Programmable Gate Array) implementation. Artificial Neural Network that provides efficient and effective ways of separating FECG signal from composite AECG signal has been designed. The proposed method gives an accuracy of 93.7% for R-peak detection in FHR monitoring. The designed VHDL model is synthesized and fitted into Altera’s Stratix II EP2S15F484C3 using the Quartus II version 8.0 Web Edition for FPGA implementation.

Keywords:  Fetal electrocardiogram, neural network, FPGA, VHDL

  Measurement of Physical Quantities

 E. Kawate, M. Hain:

New Scatterometer for Spatial Distribution Measurements of Light Scattering from Materials

Abstract:  A new scatterometer is composed of two ellipsoidal mirrors of revolution and an optical detection system. It enables us to absolutely measure diffuse reflectance and transmittance and to measure the spatial distribution of light scattering from almost all materials. The optical detection system has been developed both to measure total photo-intensity using a photodiode and to capture the imaging data using a CCD camera. This results in faster, more complete and often more accurate measurements than can be achieved with traditional goniometric methods and integrated sphere methods. The absolute total integrated reflectance and transmittance of well-known samples were measured and the spatial distribution of light scattering from a diffraction grating was captured and evaluated.

Keywords:  STAR GEM, CCD camera, fish-eye lens, absolute reflectance, bi-directional reflection distribution function, total integrated reflectance

Xiang Deng, W. Q. Yang:

Fusion Research of Electrical Tomography with Other Sensors for Two-phase Flow Measurement

Abstract:  The two-phase flow widely exists in the nature and industrial processes. The measurement of two-phase flows, including gas/solids, gas/liquid and liquid/liquid flows, is still challenging. Fusions of electrical tomography with conventional sensors provide possibilities to improve two-phase flow accurate measurement. In this paper, fusions of (1) electrical resistance tomography (ERT) with electromagnetic (EM) flowmeter, (2) electrical capacitance tomography (ECT) with ERT and (3) ECT with electrostatic sensor are introduced. Some research results of fusion methods are presented and discussed. This paper can provide the theoretical support for the multi-sensor fusion for two-phase flow measurement.

Keywords:  Two-phase flow measurement, electrical tomography, fusion, multi-sensor

Guan Xu, Xiaotao Li, Jian Su, Rong Chen, Jianfang Liu:

A Method for the Estimation of the Square Size in the Chessboard Image using Gray-level Co-occurrence Matrix

Abstract:  The paper proposes a new simple procedure for measuring the square size employing the gray-level co-occurrence matrix of a chessboard image. As the size of the square structure in a chessboard image provides the geometric constraint information among the corners, it is available to improve the precision of extracting corners and serve the camera calibration. The co-occurrence matrix of a chessboard image is constructed to obtain the statistic information of the grayscale distribution. The 2D offset of the matrix is parameterized to calculate the correlation which is regarded as the implication of the repetition probability of the similar textures. A descending tendency is observed in the experiments because the similarity decreases with the greater offset. However, minimum and maximum are captured in the correlation curve, which represents that the square texture reappears with the periods of one and two square size, separately. The size of the square is tested by applying the first minimum of the correlation. The experiments are performed on the horizontal and vertical directions which are corresponding to the length and the width of the square, respectively. The experiments prove that the described method has the potential to measure square size of the chessboard.

Keywords: Chessboard image, measurement, gray-level co-occurrence matrix, correlation

Top ↑

Measurement in Biomedicine

O. Smirg, O. Liberda, Z. Smekal, A.Sprlakova-Pukova:

MRI Slice Segmentation and 3D Modelling of Temporomandibular Joint Measured by Microscopic Coil

Abstract:  The paper focuses on the segmentation of magnetic resonance imaging (MRI) slices and 3D modelling of the temporomandibular joint disc in order to help physicians diagnose patients with dysfunction of the temporomandibular joint (TMJ). The TMJ is one of the most complex joints in the human body. The most common joint dysfunction is due to the disc. The disc is a soft tissue, which in principle cannot be diagnosed by the CT method. Therefore, a 3D model is made from the MRI slices, which can image soft tissues. For the segmentation of the disc in individual slices a new method is developed based on spatial distribution and anatomical TMJ structure with automatic thresholding. The thresholding is controlled by a genetic algorithm. The 3D model is realized using the marching cube method.

Keywords: Marching cubes, genetic algorithms, magnetic resonance imaging, poly-surface, 3D models

A. Phinyomark, H. Hu, P. Phukpattaranont, C. Limsakul:

Application of Linear Discriminant Analysis in Dimensionality Reduction for Hand Motion Classification

Abstract:  The classification of upper-limb movements based on surface electromyography (EMG) signals is an important issue in the control of assistive devices and rehabilitation systems. Increasing the number of EMG channels and features in order to increase the number of control commands can yield a high dimensional feature vector. To cope with the accuracy and computation problems associated with high dimensionality, it is commonplace to apply a processing step that transforms the data to a space of significantly lower dimensions with only a limited loss of useful information. Linear discriminant analysis (LDA) has been successfully applied as an EMG feature projection method. Recently, a number of extended LDA-based algorithms have been proposed, which are more competitive in terms of both classification accuracy and computational costs/times with classical LDA. This paper presents the findings of a comparative study of classical LDA and five extended LDA methods. From a quantitative comparison based on seven multi-feature sets, three extended LDA-based algorithms, consisting of uncorrelated LDA, orthogonal LDA and orthogonal fuzzy neighborhood discriminant analysis, produce better class separability when compared with a baseline system (without feature projection), principle component analysis (PCA), and classical LDA. Based on a 7-dimension time domain and time-scale feature vectors, these methods achieved respectively 95.2% and 93.2% classification accuracy by using a linear discriminant classifier.

Keywords:  Electromyography signal, EMG, uncorrelated LDA, orthogonal LDA, orthogonal fuzzy neighborhood discriminant analysis, kernel discriminant analysis, QR decomposition, feature extraction, feature projection

B. Trifkovic, I. Budak, A. Todorovic, J. Hodolic, T. Puskar, D. Jevremovic, D. Vukelic:

Application of Replica Technique and SEM in Accuracy Measurement of Ceramic Crowns

Abstract: The paper presents a comparative study of the measuring values of the marginal gap related to the ceramic crowns made by dental CAD/CAM system using the replica technique and SEM. The study was conducted using three experimental groups, which consisted of ceramic crowns manufactured by the Cerec CAD/CAM system. The scanning procedure was carried out using three specialized dental 3D digitization systems from the Cerec family – two types of extraoral optical scanning systems and an intraoral optical scanner. Measurements of the marginal gap were carried out using the replica technique and SEM. The comparison of aggregate values of the marginal gap using the replica technique showed a statistically significant difference between the systems. The measured values of marginal gaps of ceramic crowns using the replica technique were significantly lower compared to those measured by SEM. The results indicate that the choice of technique for measuring the accuracy of ceramic crowns influences the final results of investigation.

Keywords:  Accuracy, CAD/CAM, replica technique, SEM, ceramic crown

J. Přibil, D. Gogola, T. Dermek, I. Frollo:

Design, Realization and Experiments with a new RF Head Probe Coil for Human Vocal Tract Imaging in an NMR device

Abstract:  Magnetic resonance imaging (MRI) is nowadays widely used in medicine for diagnostic imaging and in research studies. The modeling of the human vocal tract acoustics has recently attracted considerable interest. This paper describes the design, realization and first MR scan experiments with a new head probe coil for vocal tract imaging in the open-air MRI equipment working in a weak magnetic field up to 0.2 T. The paper also describes an experimental setting for sound recording during the MR imaging.

Keywords:  NMR imaging, field calculation, RF probe coil, vocal tract modeling

  Measurement of Physical Quantities

Zhuxin Zhao, Gongjian Wen, Xing Zhang, Deren Li:

Model-based Estimation for Pose, Velocity of Projectile from Stereo Linear Array Image

Abstract:  The pose (position and attitude) and velocity of in-flight projectiles have major influence on the performance and accuracy. A cost-effective method for measuring the gun-boosted projectiles is proposed. The method adopts only one linear array image collected by the stereo vision system combining a digital line-scan camera and a mirror near the muzzle. From the projectile’s stereo image, the motion parameters (pose and velocity) are acquired by using a model-based optimization algorithm. The algorithm achieves optimal estimation of the parameters by matching the stereo projection of the projectile and that of the same size 3D model. The speed and the AOA (angle of attack) could also be determined subsequently. Experiments are made to test the proposed method.

Keywords:  Pose, velocity, projectile, speed, angle of attack, measurement, linear array image

J. Havelka, R. Malarić, K. Frlan:

Staged-Fault Testing of Distance Protection Relay Settings

Abstract:  In order to analyze the operation of the protection system during induced fault testing in the Croatian power system, a simulation using the CAPE software has been performed. The CAPE software (Computer-Aided Protection Engineering) is expert software intended primarily for relay protection engineers, which calculates current and voltage values during faults in the power system, so that relay protection devices can be properly set up. Once the accuracy of the simulation model had been confirmed, a series of simulations were performed in order to obtain the optimal fault location to test the protection system. The simulation results were used to specify the test sequence definitions for the end-to-end relay testing using advanced testing equipment with GPS synchronization for secondary injection in protection schemes based on communication. The objective of the end-to-end testing was to perform field validation of the protection settings, including verification of the circuit breaker operation, telecommunication channel time and the effectiveness of the relay algorithms. Once the end-to-end secondary injection testing had been completed, the induced fault testing was performed with three-end lines loaded and in service. This paper describes and analyses the test procedure, consisting of CAPE simulations, end-to-end test with advanced secondary equipment and staged-fault test of a three-end power line in the Croatian transmission system.

Keywords:  Distance protection, three-end line, Croatian power system, protection, fault, simulation, teleprotection scheme, communication

Top ↑

 Theoretical Problems of Measurement

P. Tuček, M. Tučková, E. Fišerová, J. Tuček, L. Kubáček:

Design of Experiment for Measurement of Langevin Function

Abstract:  The presented study focuses on a confrontation of the theory of regression models and theory of experiment with the real situation of determining properties of magnetic (nano)materials. Their magnetic properties can be deduced by measuring their magnetization, being the fundamental magnetic quantity of an arbitrary (nano)material. The results of the magnetization measurements determine the unknown parameters of a known nonlinear function that characterizes the (nano)material under investigation. Knowledge of the values of the unknown parameters enables to decide whether the (nano)material is suitable or not for a particular application. Thus, in this work, we present a possible approach how to estimate the unknown parameters of the nonlinear function by the regression models, taking into account a relevant linearization criterion. Then, we suggest an appropriate design for the measurement to get better estimators of the parameters.

 Keywords:  Approximation, nonlinear regression models, linearization, BLUE, D-optimal design of experiment, nanomaterial, hysteresis loop, Langevin function

Jing Wang, Qi Zhang, Shilin Wu:

Analysis of ATE Measurability Using Information Flow Model

Abstract: Since many test equipment can’t be calibrated conveniently, this paper proposed a new concept named measurability to solve the problem. The measurability is defined, and its indexes are given in detail. Selected from the models of testability, the information flow model is used to analyze the ATE (automatic test equipment) measurability. The correlative matrix of information flow model is decided according to the trace chain. Finally, a practical example is given to show the analysis process.

 Keywords:  ATE, measurability analysis, information flow model, correlative matrix

  Measurement of Physical Quantities

G. Barbato, G. Genta, A. Germak, R. Levi, G. Vicario:

Treatment of Experimental Data with Discordant Observations: Issues in Empirical Identification of Distribution

Abstract:  Performances of several methods currently used for detection of discordant observations are reviewed, considering a set of absolute measurements of gravity acceleration exhibiting some peculiar features. Along with currently used methods, a criterion based upon distribution of extremes is also relied upon to provide references; a modification of a simple, broadly used method is mentioned, improving performances while retaining inherent ease of use. Identification of distributions underlying experimental data may entail a substantial uncertainty component, particularly when sample size is small, and no mechanistic models are available. A pragmatic approach is described, providing estimation to a first approximation of overall uncertainty, covering both estimation of parameters, and identification of distribution shape.

Keywords:  Distribution shape, outlier, uncertainty, confidence region, gravimetry

Dibya Prakash Jena, Manpreet Singh, Rajesh Kumar:

Radial Ball Bearing Inner Race Defect Width Measurement using Analytical Wavelet Transform of Acoustic and Vibration Signal

Abstract:  In the present work, an experiment is carried out with a customized test setup where the seeded defects are introduced in the form of an axial groove on the inner race of a radial ball bearing. The nature of the acoustic and vibration signal bursts, and their correlation with the inner race defects, are established and estimated. Experimental investigation reveals that the analytical wavelet transform (AWT) is an effective tool for analyzing the acoustic and vibration signals, transmitted from the bearing, in order to characterize and measure the defect size. In the recent work, AWT followed by the time marginal integration (TMI) have been implemented on acoustic and vibration signals of a defective radial bearing. Size of the defect in the inner race of bearing is corroborated well with AWT scalogram. The segregation of the defect is carried out on TMI graph across the highest amplitude spike, which is due to signal burst (due to a contact of ball with bearing inner race defect). This manual demarcation on TMI graph in time axis provides the time duration (contact between a ball and the inner race defect). Using this time duration of the ball passed over bearing inner race defect, RPM of shaft mounted across bearing, and the fundamental train frequency, the defect width is estimated.  The deviation of the measured width from the actual, using the proposed method, is sought below 5%.  Summarizing, the proposed method can be reckoned  a suitable and reliable measurement of radial bearing inner race defect width from acoustic and vibration signal.

 Keywords:  Condition monitoring, analytical Wavelet transform, scalogram, time marginal integration (TMI)

Rajesh Kumar, Harish Kumar, Anil Kumar, Vikram:

Long Term Uncertainty Investigations of 1 MN Force Calibration Machine at NPL, India (NPLI)

Abstract:  The present paper is an attempt to study the long term uncertainty of 1 MN hydraulic multiplication system (HMS) force calibration machine (FCM) at the National Physical Laboratory, India (NPLI), which is used for calibration of the force measuring instruments in the range of 100 kN – 1 MN. The 1 MN HMS FCM was installed at NPLI in 1993 and was built on the principle of hydraulic amplifications of dead weights. The best measurement capability (BMC) of the machine is ± 0.025% (k = 2) and it is traceable to national standards by means of precision force transfer standards (FTS). The present study discusses the uncertainty variations of the 1 MN HMS FCM over the years and describes the other parameters in detail, too. The 1 MN HMS FCM was calibrated in the years 2004, 2006, 2007, 2008, 2009 and 2010 and the results have been reported.

 Keywords:  Force standard machine (FSM), force calibration machine (FCM), hydraulic multiplication system (HMS), best measurement capability (BMC), dead weights, uncertainty of measurement

Measurement in Biomedicine

J. Mikulka, E. Gescheidtova, K. Bartusek:

Soft-tissues Image Processing: Comparison of Traditional Segmentation Methods with 2D active Contour Methods

Abstract:  The paper deals with modern methods of image processing, especially image segmentation, classification and evaluation of parameters. It focuses primarily on processing medical images of soft tissues obtained by magnetic resonance tomography (MR). It is easy to describe edges of the sought objects using segmented images. The edges found can be useful for further processing of monitored object such as calculating the perimeter, surface and volume evaluation or even three-dimensional shape reconstruction. The proposed solutions can be used for the classification of healthy/unhealthy tissues in MR or other imaging. Application examples of the proposed segmentation methods are shown. Research in the area of image segmentation focuses on methods based on solving partial differential equations. This is a modern method for image processing, often called the active contour method. It is of great advantage in the segmentation of real images degraded by noise with fuzzy edges and transitions between objects. In the paper, results of the segmentation of medical images by the active contour method are compared with results of the segmentation by other existing methods. Experimental applications which demonstrate the very good properties of the active contour method are given.

Keywords:  Medical image processing, image segmentation, liver tumor, temporomandibular joint disc, watershed method

Top ↑

  Measurement of Physical Quantities

J. Kemppinen, F. Lackner, H. Mainaud Durand:

Validation Test of a Cam Mover Based Micrometric Pre-Alignment System for Future Accelerator Components

Abstract: Compact Linear Collider (CLIC) is a 48 km long linear accelerator currently studied at CERN. It is a high luminosity electron-positron collider with an energy range of 0.5-3 TeV. CLIC is based on a two-beam technology in which a high current drive beam transfers RF power to the main beam accelerating structures. The main beam is steered with quadrupole magnets. Main beam components have to be actively pre-aligned within 14 µm in sliding windows of 200 m. To reach the pre-alignment requirement as well as the rigidity required by nano-stabilization, a system based on eccentric cam movers is proposed for the re-adjustment of the main beam quadrupoles. Validation of the technique to the stringent CLIC requirements was started with tests in one degree of freedom on an eccentric cam mover. This paper describes the dedicated mock-up as well as the tests and measurements carried out with it. Finally, the test results are presented.

Keywords: CLIC, main beam quadrupole, eccentric cam mover, alignment

S. Seyedtabaii

Performance Evaluation of Neural Network Based Pulse-Echo Weld Defect Classifiers

Abstract: Pulse-echo ultrasonic signal is used to detect weld defects with high probability. However, utilizing echo signal for defects classification is another issue that has attracted attention of many researchers who have devised algorithms and tested them against their own databases. In this paper, a study is conducted to score the performance of various algorithms against a single echo signal database. Algorithms tested the use of Wavelet Transform (WT), Fast Fourier Transform (FFT) and time domain echo signal features and employed several NN’s architectures such as Multi-Layer Perceptron Neural Network (MLP), Self Organizing Map (SOM) and others known to be good classifiers. The average performance of all can be viewed fair (90%) while some algorithms render success rate of about 94%. It seems that acquiring higher success rates out of a single fixed angle probe pulse-echo set up needs new arrangements of data collection, which is under investigation.

Keywords:  Nondestructive testing, Pulse-Echo ultrasonic; neural network; radial basis function; self organizing map; Wavelet Transform

P. Petrović:

Frequency and Parameter Estimation of Multi-Sinusoidal Signal

Abstract: Estimating the fundamental frequency and harmonic parameters is basic for signal modeling in a power supply system. This paper presents a complexity-reduced algorithm for signal reconstruction in the time domain from irregularly spaced sampling values. Differing from the existing parameter estimation algorithms, either in power quality monitoring or in harmonic compensation, the proposed algorithm enables a simultaneous estimation of the fundamental frequency, the amplitudes and phases of harmonic waves. The reduction in complexity is achieved owing to completely new analytical and summarized expressions that enable a quick estimation at a low numerical error. It is proved that the estimation performance of the proposed algorithm can attain Cramer-Rao lower bound (CRLB) for sufficiently high signal-to-noise ratios. The proposed algorithm can be applied in signal reconstruction, spectral estimation, system identification, as well as in other important signal processing problems. The simulation and experimental results verify the effectiveness of the proposed algorithm.

Keywords: Band-limited signals, fundamental frequency and Fourier coefficient estimation, analytical solutions, signal reconstruction, time domain

J. Valíček, M. Držík, T. Hryniewicz, M. Harničárová, K. Rokosz, M. Kušnerová, K. Barčová, D. Bražina:

Non-Contact Method for Surface Roughness Measurement After Machining

Abstract: The paper deals with the measurement and identification of surfaces after machining in a non-contact manner. It presents a new modified measurement method and its implementation, the results of intensity distribution in the defocusing plane, their analysis and interpretation. The scanned intensity distribution at the defocusing plane gives information necessary to assess the second derivatives, and thus, surface functions which can be used to determine groove curvatures of the real surface morphology. The proposed method of measurement has proved to be very sensitive in evaluating the differences between surface finishing methods by which the measured surface standards (etalons) were machined. Two methods of machining were chosen: face grinding and planning.  By comparing the roughness standard values Ra, there were obtained relationships between these values and the parameter of the characteristic frequency of vertical inequality being measured according to the presented method. A good correlation between the measured and surface standard values with the correlation coefficient taking a range of values from 0.8 to 1 was achieved.

Keywords: Surface roughness, non-contact measurement, surface finishing methods

K. Arun Venkatesh, N. Mathivanan:

Design of MEMS Accelerometer based Acceleration Measurement System for Automobiles

Abstract: 

Design of an acceleration measurement system using a MEMS accelerometer to measure acceleration of automobiles in all the three axes is presented. Electronic stability control and anti-lock breaking systems in automobiles use the acceleration measurements to offer safety in driving. The system uses an ARM microcontroller to quantize the outputs of accelerometer and save the measurement data on a microSD card. A LabVIEW program has been developed to analyze the longitudinal acceleration measurement data and test the measurement system. Random noises generated and added with measurement data during measurement are filtered by a Kalman filter implemented in LabVIEW. Longitudinal velocity of the vehicle is computed from the measurement data and displayed on a graphical chart. Typical measurement of velocity of a vehicle at different accelerations and decelerations is presented.

Keywords: MEMS Accelerometer, acceleration measurement, ARM microcontroller, LabVIEW, Kalman filter

M. Harničárová, J. Valíček, M. Kušnerová, R. Grznárik, J. Petrů, L. Čepová:

A New Method for the Prediction of Laser Cut Surface Topography

Abstract: The submitted contribution focuses on the clarification of a laser beam cutting technology especially from the point of view of created surface topography. It provides a new view on a deformation process caused by laser beam action and on possibilities of using the surface topography. The measurement and characterisation of surface topography was performed in depth traces using a contact profilometer Surftest SJ 401 and by and an optical-contact profilometer Talysurf CLI 2000 (measured from the top edge of the sample). Thanks to this procedure, it was possible to observe and to measure a development of the numerical values of the surface (profile) roughness parameter Ra. Based on the measurement of the surface topography, there were analyzed and interpreted data with a purpose to theoretically describe surface topography and to develop an analytical solution for the profile topographical function. By using the profile topographical function, it is possible to solve the practical problems the most engineers and users face in laser beam cutting technology (LBC) process, as well as to maximize LBC manufacturing system performance and to determine the values of the process parameters that will reach the desired product quality.

Keywords: Laser cutting, surface topography, prediction, deformation parameters, topographic function

P. Marcon, K. Bartusek, Z. Dokoupil, E. Gescheidtova:

Diffusion MRI: Mitigation of Magnetic Field Inhomogeneities

Abstract: The article reports on certain artifacts that emerge during the in vitro diffusion-weighted imaging of physical samples. In this context, the authors analyze the influence of magnetic field inhomogeneity, temperature, or eddy currents and consider artifact mitigation procedures. A technique reducing the examined spurious effects was designed, experimentally verified, and denominated as the three measurement method. The technique proved to be useful mainly for the evaluation of a DWI image measured with a diffusion gradient in the z axis, where the relative measurement error decreased to 3.38 % (during measurement using two images, the relative error was greater than 19 %). For small errors within the measurement of diffusion constants of a deionized water sample (< 5 %) it was necessary to select a b-factor value larger than 200·106 s.m-2. Temperature stabilization with accuracy better than 0.1 °C during the entire measuring process is a necessary prerequisite for the measurement of biological or material samples with relative accuracy lower than 1 %.

Keywords: Correction, diffusion, inhomogeneity, eddy currents, magnetic resonance

Top ↑

 Theoretical Problems of Measurement

Z. Domotor:

Algebraic Frameworks for Measurement in the Natural Sciences

Invited paper                                                   

Abstract: The goals of this paper fall into three related areas: (i) we present an overview of a universal algebraic paradigm in which measurement specialists can construct formal models of measurement in a unified manner and systematically reason about a large class classical measurement operations, (ii) we construct convenient von Neumann quantity algebras and quantity-channels between them to represent measurements, and introduce the dual framework of state spaces and state-channels between them to investigate the statistical structure of measurements, and (iii) we provide several detailed examples that illustrate the power and versatility of algebraic approaches to measurement procedures.

Keywords: Discretization, duality, measurement operation, pointer quantity, quantity algebra, quantity-channel, state-channel, state space

V. Witkovsky:

Estimation, Testing, and Prediction Regions of the Fixed and Random Effects by Solving the Henderson’s Mixed Model Equations

Invited paper

Abstract: We present a brief overview of the methods for making statistical inference (testing statistical hypotheses, construction of confidence and/or prediction intervals and regions) about linear functions of the fixed effects and/or about the fixed and random effects simultaneously, in conventional simple linear mixed model. The presented approach is based on solutions from the Henderson’s mixed model equations.

Keywords: Linear mixed model, mixed model equations, fixed effects, random effects, REML, BLUP, EBLUP, MSE, Satterthwaite approximation, Fai-Cornelius approximation, Harville-Jeske and Prasad-Rao approximation, Kenward-Roger approximation

  Measurement of Physical Quantities

F. Ansarudin, Z. Abbas, J. Hassan, N. Z. Yahaya, M. A. Ismail:

A Simple Insulated Monopole Sensor Technique for Determination of Moisture Content in Hevea Rubber Late         

Abstract: This paper describes the application of a SMA stub contact panel as an insulated monopole sensor for determination of moisture content in hevea rubber latex. Comparison results between measured and calculated reflection coefficient using King’s model are presented. Calibration equations relating moisture content to phase shift have been established in the frequency range from 100 MHz to 5 GHz. The accuracy of the technique was 1.3% when compared to actual moisture content obtained using the gravimetric method.

Keywords: Reflection coefficient, phase shift, relative error

R. Sotner, A. Kartci, J. Jerabek, N. Herencsar, T. Dostal, K. Vrba:

An Additional Approach to Model Current Followers and Amplifiers with Electronically Controllable Parameters from Commercially Available ICs

Abstract:  Several behavioral models of current active elements for experimental purposes are introduced in this paper. These models are based on commercially available devices. They are suitable for experimental tests of current- and mixed-mode filters, oscillators, and other circuits (employing current-mode active elements) frequently used in analog signal processing without necessity of onchip fabrication of proper active element. Several methods of electronic control of intrinsic resistance in the proposed behavioral models are discussed. All predictions and theoretical assumptions are supported by simulations and experiments. This contribution helps to find a cheaper and more effective way to preliminary laboratory tests without expensive on-chip fabrication of special active elements.

Keywords: Intrinsic resistance, current and voltage gain control, current follower and amplifier, behavioral modeling

Q. Yousef, M. B. I. Reaz, M. A. M. Ali:

The Analysis of PPG Morphology: Investigating the Effects of Aging on Arterial Compliance

Abstract:  This study presents the variations of photoplethysmogram (PPG) morphology with age. PPG measurement is done noninvasively at the index finger on both right and left hands for a sample of erectile dysfunction (ED) subjects. Some parameters are derived from the analysis of PPG contour showed in association with age. The age is found to be an important factor that affects the contour of PPG signals which accelerates the disappearance of PPG’s dicrotic notch and PPG’s inflection point as well. Arterial compliance is found to be degraded with age due to the fall of arterial elasticity. This study approaches the establishment of usefulness of PPG’s contour analysis as an investigator to the changes in the elastic properties of the vascular system, and as a detector of early sub-clinical atherosclerosis.

Keywords: Carotid intima-media thickness, contour analysis, erectile dysfunction, photoplethysmogram, reflection index, stiffness index

Hongfeng Lv, Weiping Yan, Xiaobo Yang, Jiechao Li, Jieying Zhu:

Signal Detection of Multi-Channel Capillary Electrophoresis Chip Based on CCD

Abstract:  A kind of multi-channel capillary electrophoresis (CE) chip signal revised-highlight detection system based on CCD was developed. The output signal of the CCD sensor was processed by a series of pre-processing circuits and ADC, and then it was collected by the Field Programmable Gate Array (FPGA) chip which communicated with a host computer. The core in FPGA was designed to control the signal flow of the CCD and transfer the data to PC based on a Nios II embedded soft-processor. The application of PC was used to store the data and demonstrate the curve. The measurement of the fluorescent signals for different concentration Rhodamine B dyes is presented and the comparison with other detection systems is also discussed.

Keywords: Capillary electrophoresis, Multi-Channel, CCD, SOPC

B.M. Antić, Z.L. Mitrović, V.V. Vujičić:

A Method for Harmonic Measurement of Real Power Grid Signals with Frequency Drift using Instruments with Internally Generated Reference Frequency

Abstract:  The authors have recently developed a number of instruments for measuring harmonic composition of power grid signals. These instruments have a simple, predominantly digital architecture and they are based on an assumption that the frequency of the measured signals equals its nominal value (50 Hz, 60 Hz or 400 Hz). This approach has enabled the measurement of a high number of harmonics within a single period. However, the internal oscillator in the instrument generates the nominal frequency and cannot adapt to frequency changes in the input signal. This paper presents a method for the improvement of the operation of the developed instruments in cases when the fundamental frequency drifts from its nominal value as is the case with real power grid signals. Based on this method, modified versions of the harmonic measurement instruments have been developed. A comparison of the measurement error with and without the application of the proposed method is presented in the paper.

Keywords: Harmonics, spectral analysis, frequency stability, power grid measurements

Jian Lei, Chong Lei, Yong Zhou:

Micro Fluxgate Sensor using Solenoid Coils Fabricated by MEMS Technology

Abstract:  In this paper, we present a micro fluxgate sensor with solenoid coils. Micro-solenoid coils were used in this fluxgate sensor as excitation and sensing elements. Two identical excitation coils in inverse series were wound around the opposite sides of the rectangular-ring-shaped magnetic core, respectively. The sensing coil was placed vertically to the excitation coils and between them. Adopting gluing and chemical wet etching, iron-based nanocrystalline alloy was used as magnetic core material. This fluxgate sensor was designed to operate based on second harmonic operation principle. 100 kHz excitation currents with different effective values were selected to characterize the fabricated fluxgate sensor. From these experiments, we obtained some results from which we found out that the greatest sensitivity of 583.1 V/T was achieved with the effective excitation current of 150 mA. In the range from -500 μT to +500 μT, the fabricated fluxgate sensor can keep a good linearity. The noise power density was 13.57 nT/Hz0.5 at 1Hz and the noise RMS level was 23 nT in the frequency range of 10 mHz-25 Hz.

Keywords: Fluxgate sensor, magnetic sensor, micro-solenoid coil, nanocrystalline alloy, magnetic material

Chun-yao Lee and Yu-Hua Hsieh:

Bearing Damage Detection of BLDC Motors Based on Current Envelope Analysis

Abstract:  This paper proposes current envelope analysis (CEA) to analyze bearing fault signals in brushless direct current (BLDC) motors, and back propagation neural networks (BPNN) to automatically identify bearing faults. We made sample motors which contained different types of fault, recorded the current signals, and extracted the current features using CEA and Hilbert Huang transform (HHT) for BPNN fault identification. The results indicate that this approach can efficiently identify bearing faults in BLDC motors.

Keywords: Current envelope analysis, back propagation neural networks, Hilbert Huang transform

Jin Guofeng, Zhang Wei, Yang Zhengwei, Huang Zhiyong, Song Yuanjia, Wang Dongdong, Tian Gan:

Image Segmentation of Thermal Waving Inspection based on Particle Swarm Optimization Fuzzy Clustering Algorithm

Abstract:  The Fuzzy C-Mean clustering (FCM) algorithm is an effective image segmentation algorithm which combines the clustering of non-supervised and the idea of the blurry aggregate, it is widely applied to image segmentation, but it has many problems, such as great amount of calculation, being sensitive to initial data values and noise in images, and being vulnerable to fall into the shortcoming of local optimization. To conquer the problems of FCM, the algorithm of fuzzy clustering based on Particle Swarm Optimization (PSO) was proposed, this article first uses the PSO algorithm of a powerful global search capability to optimize FCM centers, and then uses this center to partition the images, the speed of the image segmentation was boosted and the segmentation accuracy was improved. The results of the experiments show that the PSO-FCM algorithm can effectively avoid the disadvantage of FCM, boost the speed and get a better image segmentation result.

Keywords: Image segmentation, thermal wave inspection, particle swarm optimization, fuzzy C-Mean clustering algorithm

Wen-jiang Xiang, Zhi-xiong Zhou, Dong-yuan Ge, Qing-ying Zhang, Qing-he Yao:

Camera Calibration by Hybrid Hopfield Network and Self-Adaptive Genetic Algorithm

Abstract:  A new approach based on hybrid Hopfield neural network and self-adaptive genetic algorithm for camera calibration is proposed. First, a Hopfield network based on dynamics is structured according to the normal equation obtained from experiment data. The network has 11 neurons, its weights are elements of the symmetrical matrix of the normal equation and keep invariable, whose input vector is corresponding to the right term of normal equation, and its output signals are corresponding to the fitting coefficients of the camera’s projective matrix. At the same time an innovative genetic algorithm is presented to get the global optimization solution, where the cross-over probability and mutation probability are tuned self-adaptively according to the evolution speed factor in longitudinal direction and the aggregation degree factor in lateral direction, respectively. When the system comes to global equilibrium state, the camera’s projective matrix is estimated from the output vector of the Hopfield network, so the camera calibration is completed. Finally, the precision analysis is carried out, which demonstrates that, as opposed to the existing methods, such as Faugeras’s, the proposed approach has high precision, and provides a new scheme for machine vision system and precision manufacture.

Keywords: Camera calibration, projective matrix, Hopfield neural network, self-adaptive genetic algorithm, longitudinal direction and lateral direction   

Qingle Pang, Xinyun Liu, Bo Sun, Qunli Ling:

Approximate Entropy Based Fault Localization and Fault Type Recognition for Non-solidly Earthed Network

Abstract:  For non-solidly earthed network, the fault localization of single phase grounding fault has been a problem. A novel fault localization and fault type recognition method of single phase grounding fault based on approximate entropy is presented. The approximate entropies of transient zero sequence current at both ends of healthy section are approximately equal, and the ratio is close to 1. On the contrary, the approximate entropies at both ends of fault section are different, and the ratio is far from 1. So, the fault section is located. At the same fault section, the smaller is the fault resistance, the larger is the approximate entropy of transient zero sequence current. According to the function between approximate entropy and fault resistance, the fault type is determined. The method has the advantages of transferring less data and unneeded synchronous sampling accurately. The simulation results show that the proposed method is feasible and accurate.

Keywords: Approximate entropy, fault localization, fault type recognition, non-solidly earthed network

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