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Page 224 of 977 Results 2231 - 2240 of 9762

Francesco Adamo, Gregorio Andria, Filippo Attivissimo, Nicola Giaquinto
SOIL MOISTURE MEASUREMENT WITH ACOUSTIC METHODS

The paper deals with the problem of measuring the soil moisture by an accurate and real-time method. Since no available measuring techniques provide both an accurate estimation of the soil water content and a user-friendly real-time system, the authors examine a method to assess the degree of the saturation with water in granular materials that use acoustic wave. Particularly, the influence of soil characteristics on velocity of wave propagation are analysed in systematic way. The final aim of the research is to carry out a simple and complete system for microclimate soil analysis.

Dina Šimuniæ, Zvonko Glavaš
SAR MEASUREMENTS OF DIFFERENT MIXTURES AT 900 MHz

The paper discusses measurements of Specific Absorption Rate at mobile telephone frequencies.More specifically, measurements are performed at frequency of GSM system, i.e. 900 MHz. Recently issued CENELEC standard in this field, as well as requirements of European Commission for SAR labeling of every phone are calling for creating and testing different measurement set-ups for this purpose. For this kind of testing, a mixture with required complex dielectric properties is necessary. One of the contributions presented in this paper is creating an adequate liquid with measuring its properties. Measurement system uncertainty has been assessed according to CENELEC EN 50361.

Armin Pavić
ERRORS IN MEASUREMENT OF ELECTROMAGNETIC FIELDS

The accurate measurements are essential for an effective control of human exposure to electromagnetic fields. In the paper, some systematic errors that could be introduced in the measurement of ELF electromagnetic fields are identified. The influence of measurement errors on the measurement accuracy is quantified, and the procedures for minimizing and avoiding the errors are stated.

Valeriu David, Alexandru Salceanu, Mihai Cretu
THE SURVEY OF THE ELECTROMAGNETIC ENVIRONMENT IN A RESIDENTIAL AREA TRAVERSED BY TRANSMISSION LINES

This paper presents the instrumentation and the results of measurements of the magnetic and electric fields near an overhead high-voltage transmission line that passes through a residential area. For measurements have been used two sensors created and calibrated by the authors: a sensor for magnetic field measurement and a sensor for both magnetic and electric field measurements. The measurements have been made in several days with view to estimate the influence of the overhead high-voltage transmission line on the electromagnetic environment in a residential area (block of flats).

A. Cataldo, F. De Tomasi, A. Lay-Ekuakille, M. R. Perrone, A. Trotta
RAMAN LIDAR SIGNAL FILTERING IN WATER VAPOR REMOTE SENSING

A Raman lidar (Light Detection And Ranging) can be implemented in the straightforward fashion illustrated in Fig. 1. The system operates by transmitting a laser pulse of arbitrary wavelength λ0 and recording radiation backscattered from the atmosphere as function of time to provide range information in a similar manner to a radar system. The return signal contains a strong elastically scattered component (at λ0) that is useful for profiling clouds and aerosols and also weaker inelastically scattered components that provide chemical-specific information. For profiling water vapor, we use components produced by vibrational Raman effect that produces energy shifts characteristic of the molecules in the atmosphere (3652 cm-1 for water vapor, 2331 cm-1 for nitrogen). The aim of this paper is to process lidar backscattered signal that contains water vapor and aerosol information in order to improve their recovery. Since they are affected by different kinds of noise, an appropriate filtering, with an improved recovery, represents a way to get good estimates of the bove components.

Nadža Milanović, Mladen Boršić
THE EXAMPLE OF WORKLOAD ALLOCATION ALGORITHM IN DISTRIBUTED COMPUTING ENVIRONMENT

To simplify the usage of a computer network as a virtual parallel machine, as well as to introduce the opportunity of distributed parallel computing to Visual Basic users, a DCOM-based software infrastructure has been implemented. This infrastructure is based on a masterslave model. Algorithm for workload allocation in distributed computing system used with this software infrastructure is proposed in this article. Algorithm is used in finding the simple solution of traveling salesman problem and with more complex schedule feasibility analysis.

Anagnostopoulos Ioannis, Anagnostopoulos Christos, Psoroulas Ioannis, Kouzas Georgios, Kotsakis Stavros, Loumos Vassileio, Kayafas Eleftherios
SOFTWARE MEASUREMENTS FOR PROTECTION CAPACITY OPTIMISATION IN SONET

During the last years, several types of network restoration techniques have been proposed and discussed. However it was evaluated that a single restoration technique cannot cover the wide range of customer’s requirements on survivability and economical spare channel assignment. This is due to the fact that each technique has its own feature and properties in terms of restoration time, flexibility, applied network elements and restoration cost. A proposed Alternative Shared Self-healing Ring Algorithm (ASSRA) is placed as substitution in a phase of an algorithm, which use an integrated self-healing technique, based in the principal of evolving more than one restoration techniques. These techniques are Route Diversity (RD), Shared Self-healing Rings (SSR) and Dynamic Self-Healing algorithms. The main scope of this paper is to examine the influence of the proposed ASSRA algorithm in the restoration cost.

Roman Wyżgolik
WAVELETS AND GRAPHICAL PROGRAMMING IN SEISMIC SIGNAL PROCESSING

The numerical methods based on a wavelet analysis and their application in seismic signals for the purpose of denoising and automatically identifying of the P phase arrival are presented. The methods implemented in the computer program and the results are presented. The methods are used for the low-amplitudes, therefore noisy signals, which were usually rejected because of the problem with the proper P phase arrival identification.

Jerzy Nabielec
“BLIND” CORRECTION OF THE ME ASUREMENT DYNAMIC ERROR – SIMULATION INVESTIGATIONS OF THE SECOND-ORDER SYSTEM

The paper presents a measuring system, which performs auto-correction of dynamic errors caused by its analogue input circuits. Input signal is used for selfidentification of the system parameters. Influence of sampling frequency and A/D converter resolution on the correction efficiency has been investigated. A range of the system analogue part parameters variation, which allows for the efficient correction, has been determined. A measure, which determines the effectiveness of correction as related to the measurement result without the correction has been introduced. Investigation has been carried out for the second-order inertial plants.

Manuel Fonseca da Silva, Pedro Miguel Ramos, António Cruz Serra
IMPEDANCE MEASUREMENT USING SINE FITTING ALGORITHMS

This paper describes an impedance measurement technique based on the use of a personal computer, two digitizing channels and the application of a four parameter sine fitting algorithm, that estimate amplitude, phase, offset and frequency of the voltages across the impedance under measurement and of a reference impedance. This simple and inexpensive setup leads to experimental results with accuracy comparable to those obtained with sophisticated high cost dedicated impedance measurement equipment. The results here presented, obtained by using a low cost 12 bit PC data acquisition board, for impedances with magnitudes below 1kΩ at 1kHz, show relative standard deviations of Z below 0.002% and standard deviations for the measured phase under 0.001º.

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