Wyniki wyszukiwania - BazTech

1

Site diversity performance in Ka band using a 7.3 m antenna diameter at tropical climate: a comparison of prediction models

Samat Fazdliana, Singh Mandeep Jit

Acta Geophysica

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2020

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Vol. 68, no. 4

1213--1221

EN

Site diversity gain prediction models were created to estimate mathematically the acquired benefts from the implementation of site diversity at place of choice. This work contributes to the comparison of existing gain prediction model to the gain of measured attenuation at Cyberjaya and Rawang, Malaysia. The experiment has been conducted for 4 years from 2014 to 2017, in Ka band using a large 7.3-m diameter antenna and a high elevation angle of 68.8°, together with the rain analysis at both places for the same duration. The average monthly rainfall and attenuation for 4 years were presented. The results revealed that prediction model Hodge performs better than other models, while X. Yeo and Panagopoulos models appear to exhibit very similar graph shape to the measured gain data. More research on gain development in tropical region should be conducted, as the existing prediction model appears to be less consistent with the current data.

2

Analiza porównawcza modeli regresyjnych z modelami sztucznych sieci neuronowych w zagadnieniach eksploatacji

Ruta R., Trzos M.

Problemy Eksploatacji

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2005

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nr 4

271--281

PL

W artykule przedstawiono wyniki modelowania procesu osuszania zawodnionego oleju transformatorowego. W procesie modelowania wykorzystano dane pochodzące z badań osuszania oleju prowadzonych w laboratorium oraz pomiarów osuszania oleju w warunkach eksploatacyjnych przeprowadzonych w Elektrowni Kozienice. Badania zmierzały do zbudowania, na podstawie danych doświadczalnych, modelu prognostycznego wyliczającego zawartość wody w oleju (skuteczność procesu osuszania) w zależności od parametrów procesu osuszania. Przedstawiono procesy konstruowania modeli z wykorzystaniem sztucznych sieci neuronowych oraz modeli regresyjnych. Omówiono opracowane modele oraz dokonano analizy ich przydatności do prognozowania procesu osuszania. Jako kryterium oceny przyjęto średni błąd względny odwzorowania modelowanego procesu.

EN

The modelling results of a transformer watery oil drying were presented. The data used in modelling came from the research of oil drying in laboratory and from the power station Kozienice, where the transformer works actually. Research aimed to develop a prognostic model for the calculation of water content in oil depending on drying parameters, on the basis of experimental data. Processes of constructing artificial neural network models and regression models construction are presented. The models developed were discussed and their prognostic usefulness for a drying processes were analysed. As the evaluation criterion the average relative error of the model was established.

3

Comparison of the 2d and 3d models of flutter of a palisade in an inviscid flow

Rządkowski R., Gnesin V., Kovalyov A

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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1999

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nr 115

349--356

EN

In recent years the works of the coupled fluid-structure problems appeared. The computational method used to solve this problem was based on a time-marching algorithm, so it was natural to consider a time domain flutter analysis method. The time domain method of flutter analysis is based on the simultaneous integration in time of the equation of motion for the structure and the fluid. In this work the comparison of the 2D and 3D Flutter results for the turbine cascade (IV Configuration) is shown. It was observed that the negative aerodamping coefficient calculated for the harmonic oscillation are not sufficient condition for growing oscillation during fluid-structure interaction.