arXiv subjects

Antoine Bernard

Publications and source records attributed to Antoine Bernard.

4 recordsLinked to original sources

arXiv2026

The On-Sky Performance of the LSST Camera CCD Array

The focal plane of the LSST Camera contains 189 individual science CCDs, arranged into 21 raft tower modules, along with 4 wavefront and 8 guider CCDs located in 4 additional corner RTMs. Altogether, the LSST Camera CCDs compose the largest focal plane ever constructed. The LSST Camera is the primary instrument of Rubin Observatory, which will begin the Legacy Survey of Space and Time in 2026. In this paper, we describe the on-sky performance of the LSST Camera CCDs, from receipt at NSF/DOE Vera C. Rubin Observatory in May 2024 to on-sky observations during the first year of operations. We discuss the process to establish functionality of several CCDs which were affected by an electrical short and faulty analog-digital converter, optimizations of readout timing in response to changes in the survey strategy, and implementation of enhanced focal plane safety measures through an active clearing mechanism on the CCDs. Finally, we discuss sensor features observed on-sky, and global performance during the first year of operations. The operations to date of the LSST Camera CCDs have demonstrated the capability of performing a wide, fast, and deep optical imaging survey of the entire southern sky at the Rubin Observatory.

astro-ph.IM↗

arXiv2026

The filter exchange system of the LSSTCam at the Vera C. Rubin Observatory

The Filter Exchange System of the LSSTCam at the Vera C. Rubin Observatory is a critical subsystem enabling the Legacy Survey of Space and Time (LSST) by performing rapid, repeatable exchanges among five large-format filters within a highly constrained in-camera volume. Since the start of on-sky operations in April 2025, the FES has routinely performed up to 40 filter exchanges per night, completing each change in under 90 seconds with a positioning repeatability of 100 micrometers in the focal plane. Safety and reliability are ensured through a dedicated software architecture. Drawing on over a year of operational experience, we report on the in-situ performance of this sophisticated system within the observatory environment, characterize the key performance metrics, and discuss how specific design choices have influenced system behavior and reliability in practice.

astro-ph.IM↗

arXiv2025

DNS-based dynamic context resolution for SCHC

LPWANs are networks characterised by the scarcity of their radio resources and their limited payload size. LoRaWAN offers an open, easy-to-deploy and efficient solution to operate a long-range network. To efficiently communicate using IPv6, the LPWAN working group from the IETF developed a solution called Static Context Header Compression (SCHC). It uses context rules, which are linked to a given End Device, to compress the IPv6 and UDP header. Since there may be a huge variety of End Devices profile, it makes sense to store the rules remotely and use a system to retrieve the profiles dynamically. In this paper we propose a mechanism based on DNS to find the context rules associated with an End Device, allowing it to be downloaded from an HTTP Server. We evaluate the corresponding delay added to the communications using experimental measurements from a real testbed.

cs.NI↗

arXiv2025

Distributed Resource Allocation and Application Deployment in Mesh Edge Networks

Virtual Network Embedding (VNE) approaches typically assume static or slowly-changing network topologies, but emerging applications require deployment in mobile environments where traditional methods become insufficient. This work extends VNE to constrained mesh networks of mobile edge devices, addressing the unique challenges of rapid topology changes and limited resources. We develop models incorporating device capabilities, connectivity, mobility and energy constraints to evaluate optimal deployment strategies for mobile edge environments. Our approach handles the dynamic nature of mobile networks through three allocation strategies: an integer linear program for optimal allocation, a greedy heuristic for immediate deployment, and a multi-objective genetic algorithm for balanced optimization. Our initial evaluation analyzes application acceptance rates, resource utilization, and latency performance under resource limitations. Results demonstrate improvements over traditional approaches, providing a foundation for VNE deployment in highly mobile environments.

cs.NI↗