Physical Sciences and Mathematics Commons^™

Challenges And Techniques For Simulating Line Emission, Karen P. Olsen, Andrea Pallottini, Aida Wofford, Marios Chatzikos, Mitchell Revalski, Francisco Guzmán, Gergö Popping, Enrique Vázquez-Semadeni, Georgios E. Magdis, Mark L. A. Richardson, Michaela Hirschmann, William J. Gray

Physics and Astronomy Faculty Publications

Modeling emission lines from the millimeter to the UV and producing synthetic spectra is crucial for a good understanding of observations, yet it is an art filled with hazards. This is the proceedings of “Walking the Line”, a 3-day conference held in 2018 that brought together scientists working on different aspects of emission line simulations, in order to share knowledge and discuss the methodology. Emission lines across the spectrum from the millimeter to the UV were discussed, with most of the focus on the interstellar medium, but also some topics on the circumgalactic medium. The most important quality of a …

Evaluation Of Acoustic Telemetry Grids For Determining Aquatic Animal Movement And Survival, Richard T. Kraus, Christopher M. Holbrook, Christopher S. Vandergoot, Taylor R, Stewart, Matthew D. Faust, Douglas A. Watkinson, Colin Charles, Mark A. Pegg, Eva C. Enders, Charles C. Krueger

School of Natural Resources: Faculty Publications

1. Acoustic telemetry studies have frequently prioritized linear configurations of hydrophone receivers, such as perpendicular from shorelines or across rivers, to detect the presence of tagged aquatic animals. This approach introduces unknown bias when receivers are stationed for convenience at geographic bottlenecks (e.g. at the mouth of an embayment or between islands) as opposed to deployments following a statistical sampling design.

2. We evaluated two-dimensional acoustic receiver arrays (grids: receivers spread uniformly across space) as an alternative approach to provide estimates of survival, movement and habitat use. Performance of variably spaced receiver grids (5–25 km spacing) was evaluated by simulating …

Towards The Right Ordering Of The Sequence Of Models For The Evolution Of A Population Using Agent-Based Simulation, Morgane Dumont, Johan Barthelemy, Nam N. Huynh, Timoteo Carletti

SMART Infrastructure Facility - Papers

Agent based modelling is nowadays widely used in transport and the social science. Forecasting population evolution and analysing the impact of hypothetical policies are often the main goal of these developments. Such models are based on sub-models defining the interactions of agents either with other agents or with their environment. Sometimes, several models represent phenomena arising at the same time in the real life. Hence, the question of the order in which these sub-models need to be applied is very relevant for simulation outcomes. This paper aims to analyse and quantify the impact of the change in the order of …

Monte Carlo Estimates Of Evaluation Metric Error And Bias: Work In Progress, Mucun Tian, Michael D. Ekstrand

Computer Science Faculty Publications and Presentations

Traditional offline evaluations of recommender systems apply metrics from machine learning and information retrieval in settings where their underlying assumptions no longer hold. This results in significant error and bias in measures of top-N recommendation performance, such as precision, recall, and nDCG. Several of the specific causes of these errors, including popularity bias and misclassified decoy items, are well-explored in the existing literature. In this paper we survey a range of work on identifying and addressing these problems, and report on our work in progress to simulate the recommender data generation and evaluation processes to quantify the extent of …

Room Temperature Measurements Of Higher Order Modes For The Sps Prototype Rf Dipole Crabbing Cavity, Subashini De Silva, P. Berrutti, Jean R. Delayen, N. A. Huque, Hyekyoung Park

Physics Faculty Publications

LHC High Luminosity Upgrade will be developing two local crabbing systems to increase the luminosity of the colliding bunches at the ATLAS and CMS experiments. One of the crabbing systems uses the rf-dipole cavity design that will be crabbing the beam in the horizontal plane. The fully integrated crabbing cavity has two higher order mode couplers in damping those excited modes. Currently two sets of HOM couplers have been fabricated at Jefferson Lab for prototyping and testing with the LARP crabbing cavities. This paper presents the measurements of the higher order modes with the prototype HOM couplers carried out at …

Simulation Study Of The Magnetized Electron Beam, S.A.K. Wijethunga, J.F. Benesch, Jean R. Delayen, F. E. Hannon, Geoffrey A. Krafft, M. A. Poelker, R. Suleiman

Physics Faculty Publications

Electron cooling of the ion beam plays an important role in electron ion colliders to obtain the required high luminosity. This cooling efficiency can be enhanced by using a magnetized electron beam, where the cooling process occurs inside a solenoid field. This paper compares the predictions of ASTRA and GPT simulations to measurements made using a DC high voltage photogun producing magnetized electron beam, related to beam size and rotation angles as a function of the photogun magnetizing solenoid and other parameters.