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Your search keyword '"Posch, Christoph"' showing total 2 results
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2 results on '"Posch, Christoph"'

1. Photonic Neuromorphic Accelerators for Event-Based Imaging Flow Cytometry

Author

Tsilikas, Ioannis, Tsirigotis, Aris, Sarantoglou, George, Deligiannidis, Stavros, Bogris, Adonis, Posch, Christoph, Branden, Gerd Van den, and Mesaritakis, Charis

Subjects
Physics - Optics, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

In this work, we present experimental results of a high-speed label-free imaging cytometry system that seamlessly merges the high-capturing rate and data sparsity of an event-based CMOS camera with lightweight photonic neuromorphic processing. This combination offers high classification accuracy and a massive reduction in the number of trainable parameters of the digital machine-learning back-end. The photonic neuromorphic accelerator is based on a hardware-friendly passive optical spectrum slicing technique that is able to extract meaningful features from the generated spike-trains. The experimental scenario comprises the discrimination of artificial polymethyl methacrylate calibrated beads, having different diameters, flowing at a mean speed of 0.01m/sec. Classification accuracy, using only lightweight, digital machine-learning schemes has topped at 98.2%. On the other hand, by experimentally pre-processing the raw spike data through the proposed photonic neuromorphic spectrum slicer we achieved an accuracy of 98.6%. This performance was accompanied by a reduction in the number of trainable parameters at the classification back-end by a factor ranging from 8 to 22, depending on the configuration of the digital neural network., Comment: 21 pages, 11 figures, submitted to Scientific Reports - Springer Nature

Published
2024

2. Lake ice break-up in Greenland: timing and spatiotemporal variability.

Author

Posch, Christoph, Abermann, Jakob, and Silva, Tiago

Subjects
*GREENLAND ice, *ICE on rivers, lakes, etc., *SYNTHETIC aperture radar, *SUBGLACIAL lakes, *MELTWATER, *MELTING points, *WATER depth
Abstract

Synthetic aperture radar (SAR) data from the Sentinel-1 (S1) mission with its high temporal and spatial resolution allows for an automated detection of lake ice break-up timings from surface backscatter differences across south (S), southwest (SW), and northwest (NW) Greenland (<71 ° N latitude) during the period 2017 to 2021. Median break-up dates of the 563 studied lakes range between 8 June and 10 July, with the earliest being in 2019 and the latest in 2018. There is a strong correlation between the break-up date and elevation, while a weak relationship with latitude and lake area could be observed. Lake-specific median break-up timings for 2017–2021 increase (i.e., are later) by 3 d per 100 m elevation gain. When assuming an earlier break-up timing of 8 d which corresponds to the observed median variability of ±8 d, the introduced excess energy due to a changing surface albedo from snow-covered ice surface to water translates to melting 0.4 ± 0.1 m thick ice at the melting point or heating up a water depth down to 35 ± 3 m by 1 K across the entire surface area of each respective lake. Upscaling the results to 100 486 lakes across the S, SW, and NW regions, which correspond to 64.5 % of all lakes or 62.1 % of the overall lake area in Greenland, yields an estimate of 1.8 × 10 6 TJ additional energy input. This translates to melting 5.8 Gt ice at the melting point or warming 432.3 Gt water by 1 K. [ABSTRACT FROM AUTHOR]

Published
2024
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