Nauki Techniczne

Metrology and Measurement Systems

Zawartość

Metrology and Measurement Systems | 2011 | No 3 |

Abstrakt

This paper is devoted to multiple soft fault diagnosis of analog nonlinear circuits. A two-stage algorithm is offered enabling us to locate the faulty circuit components and evaluate their values, considering the component tolerances. At first a preliminary diagnostic procedure is performed, under the assumption that the non-faulty components have nominal values, leading to approximate and tentative results. Then, they are corrected, taking into account the fact that the non-faulty components can assume arbitrary values within their tolerance ranges. This stage of the algorithm is carried out using the linear programming method. As a result some ranges are obtained including possible values of the faulty components. The proposed approach is illustrated with two numerical examples.

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Abstrakt

This paper is devoted to the problem of the appearance of a stagnation region during Karman vortex shedding. This particular phenomenon has been addressed by G. Birkhoff in his model of vortices generation. Experimental results obtained by various research methods confirm the existence of a stagnation region. The properties of this stagnation region have been described based on experimental findings involving flow visualisation and hot-wire anemometry. Special attention has been paid to the relationship between the existence of a slit in the bluff body and the size of the stagnation region. The slit takes over the role of the stagnation region as an information channel for generating vortices.

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Abstrakt

This paper presents an example of practical use of Prony's method for monitoring of power waveform fundamental harmonic fluctuations, which is required for the analysis of window synchronizations in frequency analyses in power monitoring systems. The example presented offers verification of the authors' theoretical considerations published earlier in articles about Prony's method and its opportunities for practical use for real life signals. The investigations shown are based on the least squares Prony's method, which, in connection with digital filtrations, enables estimations of fundamental frequency at the rate of even tens of times per one fundamental harmonic period.

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This paper presents the general solution of the least-squares approximation of the frequency characteristic of the data window by linear functions combined with zero padding technique. The approximation characteristic can be discontinuous or continuous, what depends on the value of one approximation parameter. The approximation solution has an analytical form and therefore the results have universal character. The paper presents derived formulas, analysis of approximation accuracy, the exemplary characteristics and conclusions, which confirm high accuracy of the approximation. The presented solution is applicable to estimating methods, like the LIDFT method, visualizations, etc.

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Abstrakt

This paper presents a universal approximation of the unit circle by a polygon that can be used in signal processing algorithms. Optimal choice of the values of three parameters of this approximation allows one to obtain a high accuracy of approximation. The approximation described in the paper has a universal character and can be used in many signal processing algorithms, such as DFT, that use the mathematical form of the unit circle. One of the applications of the described approximation is the DFT linear interpolation method (LIDFT). Applying the results of the presented paper to improve the LIDFT method allows one to significantly decrease the errors in estimating the amplitudes and frequencies of multifrequency signal components. The paper presents the derived formulas, an analysis of the approximation accuracy and the region of best values for the approximation parameters.

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Surface roughness parameter prediction and evaluation are important factors in determining the satisfactory performance of machined surfaces in many fields. The recent trend towards the measurement and evaluation of surface roughness has led to renewed interest in the use of newly developed non-contact sensors. In the present work, an attempt has been made to measure the surface roughness parameter of different machined surfaces using a high sensitivity capacitive sensor. A capacitive response model is proposed to predict theoretical average capacitive surface roughness and compare it with the capacitive sensor measurement results. The measurements were carried out for 18 specimens using the proposed capacitive-sensor-based non-contact measurement setup. The results show that surface roughness values measured using a sensor well agree with the model output. For ground and milled surfaces, the correlation coefficients obtained are high, while for the surfaces generated by shaping, the correlation coefficient is low. It is observed that the sensor can effectively assess the fine and moderate rough-machined surfaces compared to rough surfaces generated by a shaping process. Furthermore, a linear regression model is proposed to predict the surface roughness from the measured average capacitive roughness. It can be further used in on-machine measurement, on-line monitoring and control of surface roughness in the machine tool environment.

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Industrial applications require functional surfaces with a strictly defined micro-texture. Therefore engineered surfaces need to undergo a wide range of finishing processes. One of them is the belt grinding process, which changes the surface topography on a range of roughness and micro-roughness scales. The article describes the use of machined surface images in the monitoring process of micro-smoothing. Machined surface images were applied in the estimation of machined surface quality. The images were decomposed using two-dimensional Discrete Wavelet Transform. The approximation component was analyzed and described by the features representing the geometric parameters of image objects. Determined values of image features were used to create the model of the process and estimation of appropriate time of micro-smoothing.

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The work presented here, concentrates on experimental surface roughness analysis in the milling of hardened steel using a monolithic torus mill. Machined surface roughness with respect to milling process dynamics has been investigated. The surface roughness model including cutter displacements has been developed. Cutting forces and cutter displacements (vibrations) were measured in order to estimate their quantitative influence on Ra and Rz parameters. The cutter displacements were measured online using a scanning 3D laser vibrometer. The influence of cutting speed vc on surface roughness parameters (Ra, Rz) was also studied. The research revealed that real surface roughness parameters are significantly higher than those calculated on the basis of a kinematic-geometric basic model, and their values are strongly dependent on dynamic cutter displacements.

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Abstrakt

Advanced metallic material processes (titanium) are used or developed for the production of heavily loaded flying components (in fan blade construction). The article presents one process for diagnosing the blade interior by means of laser ultrasonography. The inspection of these parts, which are mainly made of titanium, requires the determination of the percentage of bonded grain sizes from around 10 to 30 μm. This is primarily due to the advantages of a high signal-to-noise ratio and good detection sensitivity. The results of the research into the internal blade structure are attached.

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Currently the high-precision event timers represent powerful tools for time measurement in various applications, including jitter measurement. Applied potential of this technology is illustrated by the example of clock jitter measurement and analysis based on the application of a high-precision event timer. The basic measurement procedures resulting in estimations of commonly used jitter parameters (such as accumulated jitter, period jitter, clock-to-clock jitter) are discussed. An approach to informal interpretation of statistical jitter characteristics based on theoretical jitter model and results of computer simulation is offered. Experimental results of jitter measurement and analysis for high-precision clock oscillators confirm the assumption that currently the event timing can provide for jitter measurement precision comparable with traditional oscilloscope-based techniques.

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The paper presents a procedure for correction of the error of an ECG signal, introduced by the skin-electrode interface. This procedure involves three main measuring-calculating stages: parametrical identification of the mathematical model of the interface, realized directly before the diagnostic measurements, registration of the signal at the output of electrodes as well as reconstruction of the input signal of the interface.

The first two stages are realized in the on-line mode, whereas the operation of signal reconstruction presents a numerical task of digital signal processing and is realized in the off-line mode through deconvolution of the registered signal with the transfer function of the skin-electrode interface.

The aim of the paper is to discuss in detail the procedure of parametric identification of the skin-electrode interface with the use of a computer system equipped with a DAQ card and LabVIEW software. The algorithm for error correction introduced by this interface is also presented.

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In this paper, we propose a concept of a continuous-time filter of constant component that exhibits a very short response in the time domain if compared to the traditional time-invariant filter. The improvement of the filter dynamics was achieved as a result of the time-varying parameters which were introduced to the filter structure. Such a designed filter is then applied in a system which switches many distorted signals which should be filtered as fast as possible. The paper is of review nature and presents both a theoretical background of the proposed filter and the results of simulations.

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Abstrakt

The error reduction technique, based on inverse transformation, for a shunt active resistance measurement using an ammeter and voltmeter is considered. When computing a corrected reading only multiplicative operations on two measurement results are used, namely squaring and division. The proposed method allows to increase re-sistance measurement accuracy by about two orders of magnitude what has been validated by both theoretical and experimental outcomes.

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This paper considers a method for indirect measuring the vertical displacement of wheels resulting from the road profile, using an inverse parametric data-driven model. Wheel movement is required in variable damping suspension systems, which use an onboard electronic control system that improves ride quality and vehicle handling in typical maneuvres. This paper presents a feasibility study of such an approach which was performed in laboratory conditions. Experimental validation tests were conducted on a setup consisting of a servo-hydraulic test rig equipped with displacement, force and acceleration transducers and a data-acquisition system. The fidelity and adequacy of various parametric SISO model structures were evaluated in the time domain based on correlation coefficient, FPE and AIC criteria. The experimental test results showed that inverse models provide accuracy of inversion, ranging from more than 70% for the ARX model structure to over 90% for the OE model structure.

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Redakcja

Editor-in-Chief
  • Janusz SMULKO, Gdańsk University of Technology, Poland
International Programme Committee
  • Andrzej ZAJĄC, Chairman, Military University of Technology, Poland
  • Bruno ANDO, University of Catania, Italy
  • Martin BURGHOFF, Physikalisch-Technische Bundesanstalt, Germany
  • Marcantonio CATELANI, University of Florence, Italy
  • Numan DURAKBASA, Vienna University of Technology, Austria
  • Domenico GRIMALDI, University of Calabria, Italy
  • Laszlo KISH, Texas A&M University, USA
  • Eduard LLOBET, Universitat Rovira i Virgili, Tarragona, Spain
  • Alex MASON, Liverpool John Moores University, The United Kingdom
  • Subhas MUKHOPADHYAY, Massey University, Palmerston North, New Zealand
  • Janusz MROCZKA, Wrocław University of Technology, Poland
  • Antoni ROGALSKI, Military University of Technology, Poland
  • Wiesław WOLIŃSKI, Warsaw University of Technology, Poland
Associate Editors
  • Zbigniew BIELECKI, Military University of Technology, Poland
  • Vladimir DIMCHEV, Ss. Cyril and Methodius University, Macedonia
  • Krzysztof DUDA, AGH University of Science and Technology, Poland
  • Janusz GAJDA, AGH University of Science and Technology, Poland
  • Teodor GOTSZALK, Wrocław University of Technology, Poland
  • Ireneusz JABŁOŃSKI, Wrocław University of Technology, Poland
  • Piotr JASIŃSKI, Gdańsk University of Technology, Poland
  • Piotr KISAŁA, Lublin University of Technology, Poland
  • Manoj KUMAR, University of Hyderabad, Telangana, India
  • Grzegorz LENTKA, Gdańsk University of Technology, Poland
  • Czesław ŁUKIANOWICZ, Koszalin University of Technology, Poland
  • Rosario MORELLO, University Mediterranean of Reggio Calabria, Italy
  • Fernando PUENTE LEÓN, University Karlsruhe, Germany
  • Petr SEDLAK, Brno University of Technology, Czech Republic
  • Hamid M. SEDIGHI, Shahid Chamran University of Ahvaz, Ahvaz, Iran
  • Roman SZEWCZYK, Warsaw University of Technology, Poland
Language Editors
  • Andrzej Stankiewicz, Gdańsk University of Technology, Poland
Technical Editors
  • Agnieszka Kondratowicz, Gdańsk University of Technology, Poland

Kontakt

Editorial Office of Metrology and Measurement Systems

Contact:
E-mail: metrology@pg.edu.pl
URL: www.metrology.pg.gda.pl
Phone: (+48) 58 347-1357

Post address:
Editorial Office of Metrology and Measurement Systems
Gdańsk University of Technology, Faculty of Electronics, Telecommunications and Informatics

Instrukcje dla autorów

Types of contributions

The following types of papers are published in Metrology and Measurement Systems:
•    invited review papers presenting the current stage of the knowledge (max. 20 edited pages, 3000 characters each),
•    research papers reporting original scientific or technological advancements (10‒12 pages),
•    papers based on extended and updated contributions presented at scientific conferences (max. 12 pages),
•    short notes, i.e. book reviews, conference reports, short news (max. 2 pages).

Manuscript preparation

The text of a manuscript should be written in clear and concise English. The form similar to “camera-ready” with an attached separate file – containing illustrations, tables and photographs – is preferred. For the details of the preferred format of the manuscripts, Authors should consult a recent issue of the journal or the sample article and the guidelines for manuscript preparation. The text of a manuscript should be printed on A4 pages (with margins of 2.5 cm) using a font whose size is 12 pt for main text and 10 pt for the abstract; an even number of pages is strongly recommended. The main text of a paper can be divided into sections (numbered 1, 2, ...), subsections (numbered 1.1., 1.2., ...) and – if needed – paragraphs (numbered 1.1.1., 1.1.2., ...). The title page should include: manuscript title, Authors’ names and affiliations with e-mail addresses. The corresponding Author should be identified by the symbol of an envelope and phone number. A concise abstract of approximately 100 words and with 3–5 keywords should accompany the main text.
Illustrations, photographs and tables provided in the camera-ready form, suitable for reproduction (which may include reduction) should be additionally submitted one per page, larger than final size. All illustrations should be clearly marked on the back with figure number and author’s name. All figures are to have captions. The list of figures captions and table titles should be supplied on separate page. Illustrations must be produced in black ink on white paper or by computer technique using the laser printer with the resolution not lower than 300 dpi, preferably 600 dpi. The thickness of lines should be in the range 0.2–0.5 mm, in particular cases the range 0.1–1.0 mm will be accepted. Original photographs must be supplied as they are to be reproduced (e.g. black and white or colour). Photocopies of photographs are not acceptable.
References should be inserted in the text in square brackets, e.g. [4]; their list numbered in citation order should appear at the end of the manuscript. The format of the references should be as follows: for a journal paper – surname(s) and initial(s) of author(s), year in brackets, title of the paper, journal name (in italics), volume, issue and page numbers. The exemplary format of the references is available at the sample article.

Manuscript submission and processing

Submission procedure. Manuscript should be submitted via Internet Editorial System (IES) ‒ an online submission and peer review system http://www.editorialsystem.com/mms
In order to submit the manuscript via IES, the authors (first-time users) must create an author account to obtain a user ID and password required to enter the system. From the account you create, you will be able to monitor your submission and make subsequent submissions.
The submission of the manuscript in two files is preferred: “Paper File” containing the complete manuscript (with all figures and tables embedded in the text) and “Figures File” containing illustrations, photographs and tables. Both files should be sent in DOC and PDF format as well as. In the submission letter or on separate page in “Figures File”, the full postal address, e-mail and phone numbers must be given for all co-authors. The corresponding Author should be identified.
Copyright Transfer. The submission of a manuscript means that it has not been published previously in the same form, that it is not under consideration for publication elsewhere, and that – if accepted – it will not be published elsewhere. The Author hereby grants the Polish Academy of Sciences (the Journal Owner) the license for commercial use of the article according to the Open Access License which has to be signed before publication.
Review and amendment procedures. Each submitted manuscript is subject to a peer-review procedure, and the publication decision is based on reviewers’ comments; if necessary, Authors may be invited to revise their manuscripts. On acceptance, manuscripts are subject to editorial amendment to suit the journal style.
An essential criterion for the evaluation of submitted manuscripts is their potential impact on the scientific community, measured by the number of repeated quotations. Such papers are preferred at the evaluation and publication stages.
Proofs. Proofs will be sent to the corresponding Author by e-mail and should be returned within 48 hours of receipt.

Other information

Author Benefits. The publication in the journal is free of charge. A sample copy of the journal will be sent to the corresponding Author free of charge.
Colour. For colour pages the Authors will be charged at the rate of 160 PLN or 80 EUR per page. The payment to the bank account of main distributor must be acquitted before the date pointed to Authors by Editorial Office.

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