Publications (18)
The XXL Survey : XXVI. Optical and near-infrared identifications of the ATCA 2.1 GHz radio sources in the XXL-S Field
Paolo Ciliegi, Nika Jurlin, Andrew Butler +7
In this paper we present the optical, near-infrared (NIR) and X-ray identifications of the 6287 radio sources detected in the 2.1 GHz deep radio survey down to a median rms of ~ 41…
Efficient Optimization of the Likelihood Function in Gaussian Process Modelling
Andrew Butler, Thomas D. Humphries, Pritam Ranjan +1
Gaussian Process (GP) models are popular statistical surrogates used for emulating computationally expensive computer simulators. The quality of a GP model fit can be assessed by a…
On the cohomology of Lie algebras associated with graphs
Marco Aldi, Andrew Butler, Jordan Gardiner +3
We describe a canonical decomposition of the cohomology of the Dani-Mainkar metabelian Lie algebras associated with graphs. As applications, we obtain explicit formulas for the thi…
Tailoring the Spectral and Directional Emissivity of Functionalized Laser Processed Surfaces
Andrew Butler, Andrew Reicks, Dennis Alexander +3
Development of methods to control the directional and spectral characteristics of thermal radiation from metallic surfaces is a critical factor enabling many important thermal mana…
Integrating prediction in mean-variance portfolio optimization
Andrew Butler, Roy H. Kwon
Prediction models are traditionally optimized independently from their use in the asset allocation decision-making process. We address this shortcoming and present a framework for…
Near-field imaging of plasmonic nanopatch antennas with integrated semiconductor quantum dots
Vasudevan Iyer, Yoong Sheng Phang, Andrew Butler +5
Plasmonic nanopatch antennas that incorporate dielectric gaps hundreds of picometers to several nanometers thick have drawn increasing attention over the past decade because they c…
Gradient boosting for convex cone predict and optimize problems
Andrew Butler, Roy H. Kwon
Prediction models are typically optimized independently from decision optimization. A smart predict then optimize (SPO) framework optimizes prediction models to minimize downstream…
The XXL Survey: XXXI. Classification and host galaxy properties of 2.1 GHz ATCA XXL-S radio sources
Andrew Butler, Minh Huynh, Ivan Delvecchio +10
The classification of the host galaxies of the radio sources in the 25 deg ultimate XMM extragalactic survey south field (XXL-S) is presented. XXL-S was surveyed at 2.1 GHz wit…
The XXL Survey XVIII. ATCA 2.1 GHz radio source catalogue and source counts for the XXL-South field
Andrew Butler, Minh Huynh, Jacinta Delhaize +12
The 2.1 GHz radio source catalogue of the 25 deg ultimate XMM extragalactic survey south (XXL-S) field, observed with the Australia Telescope Compact Array (ATCA), is presented…
SCQPTH: an efficient differentiable splitting method for convex quadratic programming
Andrew Butler
We present SCQPTH: a differentiable first-order splitting method for convex quadratic programs. The SCQPTH framework is based on the alternating direction method of multipliers (AD…
Efficient differentiable quadratic programming layers: an ADMM approach
Andrew Butler, Roy Kwon
Recent advances in neural-network architecture allow for seamless integration of convex optimization problems as differentiable layers in an end-to-end trainable neural network. In…
The XXL Survey: XXXVI. Evolution and black hole feedback of high-excitation and low-excitation radio galaxies in XXL-S
Andrew Butler, Minh Huynh, Anna Kapinska +5
The evolution of the comoving kinetic luminosity densities () of the radio loud (RL) high-excitation radio galaxies (RL HERGs) and the low-excitation radio galaxies…
Tunable Directional Filter for Mid-Infrared Optical Transmission Switching
Andrew Butler, Jack Schulz, Christos Argyropoulos
Controlling the spectral and angular response of infrared (IR) radiation is a challenging task of paramount importance to various emerging photonic applications. Here, we overcome…
Mechanically Tunable Radiative Cooling for Adaptive Thermal Control
Andrew Butler, Christos Argyropoulos
Passive radiative cooling is currently the frontier technology in renewable-energy research. In terms of extraterrestrial applications, radiative cooling is a critical component to…
Data-driven integration of norm-penalized mean-variance portfolios
Andrew Butler, Roy H. Kwon
Mean-variance optimization (MVO) is known to be sensitive to estimation error in its inputs. Norm penalization of MVO programs is a regularization technique that can mitigate the a…
Exceptional points in parity-time symmetric plasmonic Huygens metasurfaces
Andrew Butler, Christos Argyropoulos
Parity-Time (PT) symmetric optical structures exhibit several unique and interesting characteristics with the most popular being exceptional points. While the emerging concept of P…
Plasmon Enhanced Quantum Properties of Single Photon Emitters with Hybrid Hexagonal Boron Nitride Silver Nanocube Systems
Mohammadjavad Dowran, Andrew Butler, Suvechhya Lamichhane +5
Hexagonal boron nitride (hBN) has emerged as a promising ultrathin host of single photon emitters (SPEs) with favorable quantum properties at room temperature, making it a highly d…
The XXL Survey: XLIII. The quasar radio loudness dichotomy exposed via radio luminosity functions obtained by combining results from COSMOS and XXL-S X-ray selected quasars
Lana Ceraj, Vernesa SmolÄiÄ, Ivan Delvecchio +13
We studied a sample of 274 radio and X-ray selected quasars (XQSOs) detected in the COSMOS and XXL-S radio surveys at 3 GHz and 2.1 GHz, respectively. This sample was identified by…