IMEKO Event Proceedings

Page 792 of 822 Results 7911 - 7920 of 8218

V. Gradetsky, M. Knyazkov
Unmanned vehicle systems in unstructured environments: challenge and current status

The scientific and applied interest to Unmanned vehicle systems (UVS) or Unmanned guided vehicles (UGV) is growing every year and a lot of world-known universities and companies are working very hard in R&D of UVS. The fully autonomous vehicles or ones with different degrees of autonomy vehicles are used on the land, in the air, and in the sea for broad range of technologies including hazardous waste cleanup, agriculture crops processing, transportation, underwater monitoring, nuclear power station repair, as well as security, inspection, demining, military operations.The new uses for these systems may be found every day.
Real UVS has to understand control commands fast and without mistakes. They have to possess logically thinking, have possibilities of learning and training, produce decision making by themselves, to move in unknown environment without operator. However, today in practice the situation may arise when operator forced to intervene in teleoperated control because of unsufficient reliability of robot behaviour. High level of artificial intelligence and mind as well as data base and special software are required for real UVS.

Piotr Bilski
Unsupervised learning-based hierarchical diagnosis of analog circuits

The paper presents the automated diagnostic method of analog circuits combining supervised and unsupervised learning. The purpose of this sophisticated approach is to effectively distinguish easily identified states of the analyzed system from the more difficult ones. The latter are often related with existence of ambiguity groups, which create problems for the distinction of specific states. The proposed approach uses subsequently two algorithms. The first one extracts and learns to classify such “simple” training examples. The second one aims at the classification of more difficult ones. For both stages, Self-Organizing Maps and Random Forest were used, respectively. The scheme was tested on the model of the 3rd order Bessel highpass filter, confirming effectiveness of the approach.

Philippe Averlant, Claire Bartoli
UPGRADE OF THE MEDIUM AND HIGH FREQUENCY VIBRATION CALIBRATION REFERENCE EQUIPMENT AND EXTENSION TO LOW FREQUENCIES

The national accelerometry references in France are provided by the LNE. Such traceability to national standards is essential for industrial organisations using processes in which an understanding of acceleration related parameters is of primary importance in terms of quality and safety. These fields include the armaments, nuclear, aerospace and automotive industries.
The calibration of reference accelerometers for industries and other laboratories has been carried out on the LNE site at Trappes since 2006, using an absolute method involving a Michelson laser interferometer in accordance with standard ISO 16063. The bench used, which is described in article [2] is however of an old design and an upgrading program has been drawn up and carried out.
This article describes the upgrading of this bench. The characteristics of the components undergoing modifications are described. These are the laser interferometer, the shaker and the measurement system and data processing system. In order to cover requirements for traceability chains for vibration frequencies below 10 Hz, an additional specific shaker for low frequencies has been sourced.
Metrological approval was based on the consistency achieved between the calibration results for given accelerometers obtained using the new bench and those obtained using the original bench.

Milos Sedlacek, Ondrej Tomiska
Upgrading E-learning of basic measurement algorithms based on DSP and MATLAB Web Server

The paper presents an upgraded version of an application of MATLAB web server, one of MATLAB toolboxes, for teaching/learning some selected measurement algorithms important in processing discrete-time signals in measurement. The original version is described in [1] and [2]. The topics included are DFT/FFT (demonstration of DFT basic properties and DFT application in spectrum analysis and detection of week tones close to a strong tone), FIR filters (including the important moving average filter), basic IIR filters and some basics of stochastic signal processing in time domain and amplitude domain including finding SNR using correlation analysis. This upgraded version of MATLAB web server application is currently replacing an old one in teaching signal processing at Department of Measurement of the CTU in Prague, Faculty of Electrical Engineering, for both the students studying in Czech and (mostly Erasmus students) in English.

Tihomir Mihalic, Tomislav Stašic, Nastia Degiuli
UPGRADING OF A BELL PROVER

Bell provers have a wide usage for calibrating various types of flow meters by timing the bell ascendance. They are often used as a working standard. Known area of the bell along with measured displacement of the bell produce, with some measurement uncertainty, volume generated by the bell. This volume with measured time gives the flow generated by the bell.
The temperature and the pressure of the gas in the bell are not constant. Further more the temperature and the pressure at the flow meter are not equal to those in the bell due to losses in pipes. Because of that it is imperative to measure all of them. When those measurands are stored in database entire measurement can be analyzed at referent conditions.
In order to automate measurements with the bell prover, to improve the measurement uncertainty of the results, and to obtain some additional quantities like velocity and acceleration of the bell, computerized measurement equipment has been installed on the bell prover.

He Li, Zhang Feng, Ye Ming, Liu Lianqiu, Wang Beiping
UPGRADING OF THE ROCKWELL HARDNESS PRIMARY STANDARD MACHINE

According to the new definition of Rockwell hardness given by the international working group on hardness, the Rockwell hardness primary standard machine has been upgraded. As the new loading system, loading monitor system, PLC control system and laser measuring system have been developed, the function of the new primary standard machine can now meet the requirements of the new definition and its measuring uncertainty can reach the expected values.

Romeo Ciobanu, Cristina Schreiner, Marinel Temneanu
UPON THE DIFFERENCE BETWEEN THE EVOLUTION VERSUS FREQUENCY OF PD AND BREAKDOWN PROCESSES, RELATED TO PAPER FOR DC CABLES INSULATION

Significant differences between the evolution versus frequency of the PD and breakdown processes were emphasized, suggesting that the breakdown analysis, if used as unique method in quality assessment of insulating materials, proves to have limits in accuracy and may lead to errors in results interpretation.

Alexandru Salceanu, Fanel Iacobescu, Mirela-Adelaida Olteanu (Anghel)
Upon The Influence of the Real Value of Human Body Capacitance in ESD Immunity Tests

The first part of the paper is focussed on own direct measurements of human body resistancecapacitance, in indissoluble connection with two resistances: the leakage and respective, the discharge ones. There are presented methods, set-ups and argued explanations for the large dispersion of the obtained results. The human impedance (capacitance shunted by leakage resistance) was measured by performing the ratio between the well known ac voltage (as r.m.s. and frequency) and the established current. In order to determine the skin resistance between different parts of the human body (wrist, elbow, shoulder, ankle), there were performed both ac and dc measurements.
The second part aims to investigate the relationship between the real skin resistance (in the main, determined by volume resistivity, not just surface one) and the factual disturbing potential of the associated discharge in order to evaluate the impact of the series resistance in an ESD gun upon the susceptibility test results.

M. Kowalewski, Z. Czaja
USAGE OF TWO-CENTER BASIS FUNCTION NEURAL CLASSIFIERS IN COMPACT SMART RESISTIVE SENSORS

A new solution of the smart resistance sensor with the Two-Center Basis Function (TCBF) neural classifier, for which the resistance sensor is a component of an anti-aliasing filter of an ADC is proposed. The temperature measurement procedure is based on excitation of the filter by square impulses, sampling time response of the filter and processing measured voltage values by the TCBF classifier. All steps of the measurement procedure can be realized by the microcontroller and its internal devices.

Page 792 of 822 Results 7911 - 7920 of 8218