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Number of results: 8
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Abstract

The aim of the paper is to present the possibilities and limitations of using the Digital Image Correlation systems. In order to assess the measurement inaccuracies the measuring volume 1250 × 1100 mm was analysed using two cameras with sensor resolution 6 megapixels. It was stated very good accuracy of the line segment length change. It causes that observation of crack widths can be considered as precisely. Some practical information concern how determine the compatibility between crack width measured traditionally and by using DIC are given. In the second part of the paper the results of the tests concerning capacity of interface between two concrete casting at the same time were presented. Use of the optical measurement system Aramis enables the analysis of the deformation, determination of failure mode of the tested specimens and limit displacement between edges of the interface.

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Authors and Affiliations

Ł. Krawczyk
Michał Gołdyn
ORCID: ORCID
Tadeusz Urban
ORCID: ORCID
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Abstract

The paper considers an algorithm for increasing the accuracy of measuring systems operating on moving objects. The algorithm is based on the Kalman filter. It aims to provide a high measurement accuracy for the whole range of change of the measured quantity and the interference effects, as well as to eliminate the influence of a number of interference sources, each of which is of secondary importance but their total impact can cause a considerable distortion of the measuring signal. The algorithm is intended for gyro-free measuring systems. It is based on a model of the moving object dynamics. The mathematical model is developed in such a way that it enables to automatically adjust the algorithm parameters depending on the current state of measurement conditions. This makes possible to develop low-cost measuring systems with a high dynamic accuracy. The presented experimental results prove effectiveness of the proposed algorithm in terms of the dynamic accuracy of measuring systems of that type.

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Authors and Affiliations

Dimitar Dichev
Hristofor Koev
Totka Bakalova
Petr Louda
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Abstract

The paper presents a new method for building measuring instruments and systems for gyro-free determination of the parameters of moving objects. To illustrate the qualities of this method, a system for measuring the roll, pitch, heel and trim of a ship has been developed on its basis. The main concept of the method is based, on one hand, on a simplified design of the base coordinate system in the main measurement channel so as to reduce the instrumental errors, and, on the other hand, on an additional measurement channel operating in parallel with the main one and whose hardware and software platform makes possible performing algorithms intended to eliminate the dynamic error in real time. In this way, as well as by using suitable adaptive algorithms in the measurement procedures, low-cost measuring systems operating with high accuracy under conditions of inertial effects and whose parameters (intensity and frequency of the maximum in the spectrum) change within a wide range can be implemented.

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Authors and Affiliations

Dimitar Dichev
Petr Louda
Totka Bakalova
Hristofor Koev
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Abstract

We present a prototype of a simple, low-cost setup for a fast scatterometric surface texture measurements. We used a total integrated scatter method (TIS) with a semiconductor laser (λ =  638 nm) and a Si photodiode. Using our setup, we estimated the roughness parameters Rq for two reference surfaces (Al mirrors with flatness λ/10) and seven equal steel plates to compare. The setup is easily adaptable for a fast, preliminary manufacturing quality control. We show is possible to construct a low-cost measurement system with nanometric precision.

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Authors and Affiliations

D. Kucharski
H. Zdunek
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Abstract

International standards from IEC and IEEE regulate power grid parameters such as theRMSvalue, frequency, harmonic and interharmonic distortion, unbalance or the presence of transients, that are important to assure the quality of distributed power. Standard IEC 61000-4-30 suggests the zero crossing algorithm for the measurement of the power grid frequency, but also states that different algorithms can be used. This paper proposes a new algorithm, the Fractional Interpolated Discrete Fourier Transform, FracIpDFT, to estimate the power grid frequency, suitable for implementation in resource limited embedded measurement systems. It is based on the non-integer Goertzel algorithm followed by interpolation at non-integer multiples of the DFT frequency resolution. The proposed algorithm is validated and its performance compared with other algorithms through numerical simulations. Implementation details of the FracIpDFT in an ARM Cortex M4 processor are presented along with frequency measurement results performed with the proposed algorithm in the developed system.
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Authors and Affiliations

Nuno M. Rodrigues
1
Fernando M. Janeiro
2
Pedro M. Ramos
1

  1. Instituto de Telecomunicações, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
  2. Instituto de Telecomunicações, Universidade de Évora, 7000-671 Évora, Portugal
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Abstract

History has shown different approaches to improving productivity the way of companies do business. Since the early 1900s, the development of different production systems has played an increasingly remarkable role in global manufacturing countries. It seems, that the growth of understanding has widened the ideology of production systems used up to current ones. This article examines the development path of business development. It evaluates the suitability of the key tools used to support change in a modern business model in a customer-driven project business environment.
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Authors and Affiliations

Jyri Vuorela
1
Mikael Ollikainen
1
Vesa Salminen
2
Juha Varis
1

  1. Energy Systems, LUT University, Finland
  2. Smart Research Center, Häme University of Applied Sciences, Finland
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Abstract

The following article collects and describes several practical problems that can be encountered when performing geophysical field measurements using the electrical resistivity tomography (ERT) method. The methodology of work carried out with the Terrameter LS apparatus of the Swedish company ABEM (currently the company has changed its name to GUIDELINE GEO) was presented and discussed. The attention was paid to interesting solutions that increase the efficiency of works, especially in works related to linear investments. Errors that may appear during the use of the roll-along method are indicated, in particular, those appearing in measurements where too long measurement sections are transferred, as well as problems resulting from high electrode earthing, nonlinear profile traces and variable morphology. It describes how the use of different measurement systems affects the depth of prospecting, and which systems cope well in the area with disturbances. The article also emphasizes that the work should be properly planned before starting field research.
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Authors and Affiliations

Grzegorz Pacanowski
1
ORCID: ORCID
Maciej Maślakowski
2
ORCID: ORCID
Anna Lejzerowicz
2
ORCID: ORCID

  1. Polish Geological Institute – National Research Institute, Rakowiecka 4, 00-975 Warsaw, Poland
  2. Warsaw University of Technology, Faculty of Civil Engineering, Al. Armii Ludowej 16, 00-637 Warsaw, Poland
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Abstract

This article presents a system of precise navigation for a visually impaired person which uses GPS navigation and an infrared sensor in the form of an infrared matrix. The presented system allows determining the orientation and distance of a blind person relative to a selected object, e.g. a wall or road edge. The application of the above solution facilitates a significant increase in the accuracy of determining the position of a blind person compared to the accuracy offered by commonly used ground satellite devices. The system uses thermal energy accumulated in the environment without the need to generate additional signals. The main parts of the system are a simple infrared matrix, data processing system and vibrating wristband. Messages and navigation warnings are sent to a blind person in the form of a vibration code. The article describes the method of determining the path of a specified width and distance from the wall of a building, curb, etc., along which a blind person should move. The article additionally describes the method of determining the orientation of a blind person depending on the selected object. Such a method facilitates verifying whether the visually impaired person is moving according to the indicated direction. The method can also be used to navigate mobile robots. Due to the use of natural energy for data registration and processing, the mobile navigation system can be operated for a long time without the need to recharge the battery.

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Bibliography

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Authors and Affiliations

Paweł Marzec
1
Andrzej Kos
1

  1. AGH University of Science and Technology, Faculty of Computer Science, Electronics and Telecommunications, al. Mickiewicza 30, 30-059 Krakow, Poland

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