41 research outputs found
Silicon Photonic Architecture for Training Deep Neural Networks with Direct Feedback Alignment
There has been growing interest in using photonic processors for performing
neural network inference operations; however, these networks are currently
trained using standard digital electronics. Here, we propose on-chip training
of neural networks enabled by a CMOS-compatible silicon photonic architecture
to harness the potential for massively parallel, efficient, and fast data
operations. Our scheme employs the direct feedback alignment training
algorithm, which trains neural networks using error feedback rather than error
backpropagation, and can operate at speeds of trillions of multiply-accumulate
(MAC) operations per second while consuming less than one picojoule per MAC
operation. The photonic architecture exploits parallelized matrix-vector
multiplications using arrays of microring resonators for processing
multi-channel analog signals along single waveguide buses to calculate the
gradient vector for each neural network layer in situ. We also experimentally
demonstrate training deep neural networks with the MNIST dataset using on-chip
MAC operation results. Our novel approach for efficient, ultra-fast neural
network training showcases photonics as a promising platform for executing AI
applications.Comment: 15 pages, 6 figure
Diversity and Distribution of Archaea in the Mangrove Sediment of Sundarbans
Mangroves are among the most diverse and productive coastal ecosystems in the tropical and subtropical regions. Environmental conditions particular to this biome make mangroves hotspots for microbial diversity, and the resident microbial communities play essential roles in maintenance of the ecosystem. Recently, there has been increasing interest to understand the composition and contribution of microorganisms in mangroves. In the present study, we have analyzed the diversity and distribution of archaea in the tropical mangrove sediments of Sundarbans using 16S rRNA gene amplicon sequencing. The extraction of DNA from sediment samples and the direct application of 16S rRNA gene amplicon sequencing resulted in approximately 142 Mb of data from three distinct mangrove areas (Godkhali, Bonnie camp, and Dhulibhashani). The taxonomic analysis revealed the dominance of phyla Euryarchaeota and Thaumarchaeota (Marine Group I) within our dataset. The distribution of different archaeal taxa and respective statistical analysis (SIMPER, NMDS) revealed a clear community shift along the sampling stations. The sampling stations (Godkhali and Bonnie camp) with history of higher hydrocarbon/oil pollution showed different archaeal community pattern (dominated by haloarchaea) compared to station (Dhulibhashani) with nearly pristine environment (dominated by methanogens). It is indicated that sediment archaeal community patterns were influenced by environmental conditions