arXiv subjects

Andrew Nelson

Publications and source records attributed to Andrew Nelson.

9 recordsLinked to original sources

arXiv2026

SbDN: Source-based TSN-Grade Deterministic Networking using Commodity Switches

Deterministic networking is essential for safety-critical applications in automotive, industrial, and aerospace systems, where bounded end-to-end latency must be guaranteed for time-critical traffic. Time-Sensitive Networking (TSN) provides the mechanisms to achieve such guarantees, but its deployment requires expensive TSN-capable switches at every hop and complex per-switch configuration that hinders runtime reconfiguration. This paper presents SbDN, a Multi-Agent Source-based architecture that achieves TSN-grade determinism using commodity Ethernet switches. SbDN moves all scheduling intelligence to a centralized controller composed of three cooperating agents and enforces the computed configurations exclusively at the source endpoints, leaving switches as simple forwarding elements. We propose two methods: Temporal Network Partitioning (TNP), which provides strict temporal isolation on pure FIFO switches, and Traffic Prioritization (TP), which leverages strict-priority queuing at switches to enable work-conserving best-effort traffic. Both methods are formally proven to guarantee that all admitted time-critical flows meet their end-to-end deadlines. Evaluation across 40 benchmark configurations on two topologies shows that TNP and TP achieve 100\% admission of time-critical traffic in every scenario, with scheduling times in the low-millisecond range suitable for safe runtime reconfiguration. Compared to a standard TSN baseline, SbDN delivers superior time-critical latency at a fraction of the switch infrastructure cost, while offering competitive best-effort throughput through the choice between the two methods.

cs.NI↗

arXiv2026

V-TSN: A Software-Defined TSN Overlay for General-Purpose Networks

Time-Sensitive Networking (TSN) extends Ethernet with deterministic communication for time-critical applications such as industrial automation, in-vehicle networks, and cyber-physical systems. However, realizing TSN behavior without dedicated hardware is difficult. During design and validation, offline simulation cannot run application software at real-time speed when costly specialized TSN hardware is not (yet) available. At deployment time, many systems run on general-purpose and cloud networks with no native TSN support, where provisioning full TSN hardware is unnecessary or impractical for applications that tolerate relaxed timing. In this paper, we introduce Virtual Time-Sensitive Networking (V-TSN), a software-defined overlay that realizes gPTP-based synchronization and TSN traffic shaping over general-purpose, non-deterministic networks without specialized hardware. V-TSN runs in real time alongside the unmodified application stack, serving both as a development-time emulation tool and as a cost-efficient deployment option where relaxed timing is acceptable. In a cloud-based deployment, V-TSN achieves an average clock offset below 200 microseconds, it isolates time-critical traffic through a virtual Time-Aware Shaper (TAS), and it enforces per-class bandwidth reservations through a virtual Credit-Based Shaper (CBS).

cs.NI↗

arXiv2026

What LLMs Must Forget to Teach Effectively: A DIY Approach to Premodern Japanese Language Pedagogy

We discuss a novel approach to Premodern Japanese Language Pedagogy (PJLP) with potential applications in other languages and fields. The integration of artificial intelligence into education has largely operated as a top-down project, affording minimal agency to everyday users. This dynamic mirrors the broader frontier model ecosystem, which concentrates massive human and financial resources within a few labs. Drawing inspiration from grassroots initiatives such as the DIY and Maker movements, this paper advocates for an approach to AI in Education that fosters instructional and student agency over the pedagogical process. Specifically, we discuss a tutoring framework for textual analysis in the context of a graduate seminar in premodern Japanese literature, as well as a bilingual interactive dictionary and a conversational partner created for a language course in Classical Japanese. Created through prompt engineering as custom instances of a Large Language Model (LLM), these three tools are designed to counteract the tendency of out-of-the-box LLMs to either bypass student effort through over-explanation or misguide learners via hallucinations. To illustrate how this approach can promote active comprehension and pedagogical alignment, we provide transcripts (logs) of actual exchanges, sample instructions (system prompts), and guidance for instructors curious about exploring this approach in a variety of fields (starter kit).

cs.HC↗

arXiv2025

Chromium-doped uranium dioxide fuels: A review

UO2 doped with parts per million Cr2O3 powder is considered a potential near term accident tolerant fuel candidate. Here, the results of decades of industry and academic research into Cr-doped UO2 are analyzed and their shortcomings are critiqued. Focusing on the incorporation mechanisms of Cr into the fuel matrix, we explore a mechanistic understanding of the characteristic properties of Cr-doped UO2, notably, enhanced fission gas retention attributed to enlarged grain sizes following sintering, along with marginal improvements in the thermophysical properties. The findings of recent X-ray Adsorption Near Edge Spectroscopy studies were compared and put into conversation with historic data regarding the incorporation of Cr in UO2. On the basis of defect mechanisms, the case is made for the substitutional incorporation of Cr governing the lattice solubility but not the enhanced U diffusivity. Instead, Cr/Cr2O3 redox chemistry in a well-defined oxygen potential explains the differences in the U diffusivity and O/M ratio. The primary mechanism of doping-enhanced grain growth is found to be liquid assisted sintering due to a CrO(l) eutectic phase at the grain boundaries. The role of inhomogeneities in Cr concentration in UO2 at various length scales across the materials microstructure is highlighted and connected to promising experimental and modeling work to fill in the gaps in the current understanding of Cr-doped UO2. The review ends with an outline of future works that combine meticulous irradiation studies and high resolution experiments with next generation modeling and simulations techniques empowered by machine learning advances to accelerate the fabrication and adoption of Cr-doped UO2 light water reactors.

cond-mat.mtrl-sci↗

arXiv2023

The effect of direct electron beam patterning on the water uptake and ionic conductivity of Nafion thin films

We report the effect of electron-beam patterning on the water uptake and ionic conductivity of Nafion films using a combination of x-ray photoelectron spectroscopy, quartz crystal microbalance studies, neutron reflectometry, and AC impedance spectroscopy. The aim was to more fully characterize the nature of the nanoscale patterned Nafion structures recently used as a key element in novel ion-to-electron transducers by Gluschke et al. To enable these studies, we develop the electron beam patterning process for large areas, achieving patterning speeds approaching 1 cm$^{2}$/hr, and patterned areas as large as 7 cm$^{2}$ for the neutron reflectometry studies. We ultimately show that electron-beam patterning affects both the water uptake and the ionic conductivity, depending on film thickness. We see Type-II adsorption isotherm behaviour for all films. For thick films (~230 nm), we see a strong reduction in water uptake with electron-beam patterning. In contrast, for thin films (~30 nm), electron-beam patterning enhances water uptake. Notably, we find that for either thickness the reduction in ionic conductivity arising from electron-beam patterning is kept to less than an order of magnitude. We propose mechanisms for the observed behaviour based on the known complex morphology of Nafion films to motivate future studies of electron-beam processed Nafion.

cond-mat.soft↗

arXiv2023

Affordable Artificial Intelligence -- Augmenting Farmer Knowledge with AI

Farms produce hundreds of thousands of data points on the ground daily. Farming technique which combines farming practices with the insights uncovered in these data points using AI technology is called precision farming. Precision farming technology augments and extends farmers' deep knowledge about their land, making production more sustainable and profitable. As part of the larger effort at Microsoft for empowering agricultural labor force to be more productive and sustainable, this paper presents the AI technology for predicting micro-climate conditions on the farm. This article is a chapter in publication by Food and Agriculture Organization of the United Nations and International Telecommunication Union Bangkok, 2021. This publication on artificial intelligence (AI) for agriculture is the fifth in the E-agriculture in Action series, launched in 2016 and jointly produced by FAO and ITU. It aims to raise awareness about existing AI applications in agriculture and to inspire stakeholders to develop and replicate the new ones. Improvement of capacity and tools for capturing and processing data and substantial advances in the field of machine learning open new horizons for data-driven solutions that can support decision-making, facilitate supervision and monitoring, improve the timeliness and effectiveness of safety measures (e.g. use of pesticides), and support automation of many resource-consuming tasks in agriculture. This publication presents the reader with a collection of informative applications highlighting various ways AI is used in agriculture and offering valuable insights on the implementation process, success factors, and lessons learnt.

eess.SP↗

arXiv2019

Chemically reversible isomerization of inorganic clusters

Structural transformations in molecules and solids have generally been studied in isolation, while intermediate systems have eluded characterization. We show that a pair of CdS cluster isomers provides an advantageous experimental platform to study isomerization in well-defined atomically precise systems. The clusters coherently interconvert over an est. 1 eV energy barrier with a 140 meV shift in their excitonic energy gaps. There is a diffusionless, displacive reconfiguration of the inorganic core (solid-solid transformation) with first order (isomerization-like) transformation kinetics. Driven by a distortion of the ligand binding motifs, the presence of hydroxyl species changes the surface energy via physisorption, which determines phase stability in this system. This reaction possesses essential characteristics of both solid-solid transformations and molecular isomerizations, and bridges these disparate length scales.

physics.chem-ph↗

arXiv2012

Collider searches for dark matter in events with a Z boson and missing energy

Searches for dark matter at colliders typically involve signatures with energetic initial-state radiation without visible recoil particles. Searches for mono-jet or mono-photon signatures have yielded powerful constraints on dark matter interactions with Standard Model particles. We extend this to the mono-Z signature and reinterpret an ATLAS analysis of events with a Z boson and missing transverse momentum to derive constraints on dark matter interaction mass scale and nucleon cross sections in the context of effective field theories describing dark matter which interacts via heavy mediator particles with quarks or weak bosons.

hep-ex↗

arXiv2010

Phase Phenomena in Supported Lipid Films under Varying Electric Potential

We model cyclic voltammetry experiments on supported lipid films where a non-trivial dependence of the capacitance on the applied voltage is observed. Previously, based on a mean-field treatment of the Flory-Huggins type, under the assumption of strongly screened electrostatic interactions, it has been hypothesized that peaks in the capacitance-vs-voltage profiles correspond to a sequence of structural or phase transitions within the interface. To examine this hypothesis, in this study we use both mean-field calculations and Monte Carlo simulations where the electrostatic effects due to the varying electric potential and the presence of salt are accounted for explicitly. Our main focus is on the structure of the film and the desorption-readsorption phenomena. These are found to be driven by a strong competition for the progressively charged-up (hydrophobic) surface between lipid hydrocarbon tails and the electrode counterions (cations). As the surface charge density is raised, the following phase phenomena within the interface are clearly observed: (i) a gradual displacement of the monolayer from the surface by the counterions, leading to complete monolayer desorption and formation of an electric double layer by the surface, (ii) a transformation of the monolayer into a bilayer upon its desorption, (iii) in the case of zwitterionic (or strongly polar) lipid head groups, the desorption is followed by the bilayer readsorption to the electrode via interaction with the electric double layer and release of the excess counterions into the bulk solution. We argue then that the voltammetry peaks are associated with a stepwise process of formation of layers of alternating charge: electric double layer - upon film desorption, triple or multi-layer - upon film readsoption.

cond-mat.soft↗