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In Wavelength Division Multiplexed (WDM) transmission systems the following categories of optical amplifiers are used: Erbium Doped Fiber Amplifier (EDFA), Raman amplifier (RAMAN) and Semiconductor Optical Amplifier (SOA). A hybrid amplifier can be formed using these amplifiers to combine the merits and to compensate for the demerits of different amplifiers. In this study, the performance of different hybrid optical amplifiers (EDFA-EDFA-EDFA, RAMAN-EDFA-EDFA, EDFA-EDFA-RAMAN, RAMAN-EDFA-RAMAN, EDFA-EDFA-SOA) for 64x10 Gbps Dense Wavelength Division Multiplexed (DWDM) system has been compared. The performance has been analyzed on the basis of transmission distance from 80-200 km in terms of output power, Q-factor and bit error rate. The impact of modulation formats (NRZ and RZ) on hybrid optical amplifiers has been further investigated and it is found that EDFA-EDFA-EDFA provides the highest output power. The better Q value is provided by EDFA-EDFA-RAMAN up to 160 km. The least bit error rate is provided by EDFA-EDFA-RAMAN up to 160 km.
Image retrieval is a challenging and important research applications
like digital libraries and medical image databases. C ontent-based image retrieval
is useful in retrieving images from database based on the feature vector generated
with the help of the image features. In this study, researchers present image
retrieval based on the Genetic algorithm. The shape feature and morphological
based texture features are extracted images in the database and query image.
Then, generating chromosome based on the distance value obtained by the difference
feature vector of images in the data base and the query image. In the selected
chromosome the genetic operators like cross over and mutation are applied. After
that the best chromosome selected and displays the most similar images to the
query image. The retrieval performance of the method shows better retrieval
result.
