9762 papers found
The main scopes activities of international metrological organization are described. Correspondence of activity IMEKO TCs and CIPM CCs is analyzed. The main principles of harmonization of national standards with the OIML imeko_proceedings are defined. Possibility of interactions of IMEKO, OIML TCs and CIPM CCs are determined.
The main scopes activities of international organization for standardization in field of metrology are described. Correspondence of activity IMEKO, ISO and IEC TCs is analyzed. The main principles of harmonization of national standards with the international standards in field of metrology are defined. Possibility of interactions of IMEKO, ISO and IEC TCs are determined.
A new simple method of single soft fault detection and localization of analog parts in embedded electronic systems controlled by microcontrollers is presented. In the pre-testing stage of the method a fault dictionary is created based on the map of localization curves. In the measurement stage the time response to a stimulating square impulse of the analog part is applied to the input of the analog comparator, and measurements of duration times of subsequent impulses of output signals of the analog comparator are realized by the internal timer of the microcontroller. In the last stage, fault...
The paper describes a PC application for processing results in calibration of special weights used by Mass laboratory of National Institute of Metrology. The application named "GS 2007" is friendly used, complex and safe application. It realizes the necessary functions for calculating the mass and uncertainty of the special weights, according to OIML R 111, including the uncertainty analysis, to optimize the measurement process. The application allows data recording, interactive dialog, the visualization and the printing of the results.
This paper describes two methods for economical test of dynamic parameters ADCs in embedded Data Acquisition Systems. First method is Exponential Fit Test, second method is Wobbler Test. Common testing methods are mentioned as far the accuracy and time necessary for the complete test are concerned. The tests for fast evaluation of the dependence of an effective number of bits on frequency of input signal are described and the comparison of proposed method with the standard methods is given.
The measurement of in-phase/quadrature (IQ) imbalance parameters of radio frequency direct downconversion receivers by tone test is considered. The receiver is excited by a radio frequency sinewave, and the digital baseband output is used as the sole basis for the determination of the IQ imbalance parameters, which are the gain imbalance, quadrature skew and local oscillator leakage. A set of parameters is estimated from the baseband output of the direct downconversion receiver and the required parameters are then calculated by a transformation. The universal software radio peripheral (USRP)...
The paper is devoted to the issues of experimental analysis of residual stresses on the concrete part of pipelines – welded ball valve. A semi-destructive hole-drilling method was used for measurement, and experimental stress analysis and evaluation of residual stresses was made in accordance with the US standard ASTM E 837 – 01, as well as with use of an integral method. Residual stresses were measured both immediately after welding and after pressurising of the ball valve. This has enabled observation of the influence of pressurising on change of residual stresses in the neighbourhood of...
The increasing use of microprocessors and microcontrollers in measurement and data acquisition systems has necessitated the need for obtaining sensor response in a digital format, thus avoiding the need for an analog-to-digital conversion stage. Further, in quite of a number of automation applications, there is the need of wireless transmission of data signals over narrow gaps. The signal obtained is loaded with data from transducers measuring parameters of interest for monitoring or other reasons. Changes in resistive sensors as a result of parameters changes are obtained as a digital...
A SIFT-based Vehicle Manufacturer and Model Recognition (VMMR) method was utilized to tackle the problem of vehicle security. Distinctive parts of the vehicle frontal view such as the headlights, grill and logo area were segmented. A series of experiments were conducted in a variety of outdoor conditions, where a query image that was rotated, scaled, shifted or set in different lighting conditions, matched against a database of model images. In this work, is shown that image processing functions based on Scale Invariant Feature Transform (SIFT) measurements can be used to obtain high...
In this paper, we consider the practical issues related to positioning in WiMAX networks depending on the available measurements. The network under study is the Clearwire network deployed in Brussels capitol city. The focus lies on making the available terminal-based measurements, study the possibility of using these measurements in positioning and provide a comparison between these measurements depending on the accuracy achieved and the difficulty to obtain them.