6,455 research outputs found
The Loss Rank Principle for Model Selection
We introduce a new principle for model selection in regression and
classification. Many regression models are controlled by some smoothness or
flexibility or complexity parameter c, e.g. the number of neighbors to be
averaged over in k nearest neighbor (kNN) regression or the polynomial degree
in regression with polynomials. Let f_D^c be the (best) regressor of complexity
c on data D. A more flexible regressor can fit more data D' well than a more
rigid one. If something (here small loss) is easy to achieve it's typically
worth less. We define the loss rank of f_D^c as the number of other
(fictitious) data D' that are fitted better by f_D'^c than D is fitted by
f_D^c. We suggest selecting the model complexity c that has minimal loss rank
(LoRP). Unlike most penalized maximum likelihood variants (AIC,BIC,MDL), LoRP
only depends on the regression function and loss function. It works without a
stochastic noise model, and is directly applicable to any non-parametric
regressor, like kNN. In this paper we formalize, discuss, and motivate LoRP,
study it for specific regression problems, in particular linear ones, and
compare it to other model selection schemes.Comment: 16 page
MIRIAM: A Multimodal Chat-Based Interface for Autonomous Systems
We present MIRIAM (Multimodal Intelligent inteRactIon for Autonomous
systeMs), a multimodal interface to support situation awareness of autonomous
vehicles through chat-based interaction. The user is able to chat about the
vehicle's plan, objectives, previous activities and mission progress. The
system is mixed initiative in that it pro-actively sends messages about key
events, such as fault warnings. We will demonstrate MIRIAM using SeeByte's
SeeTrack command and control interface and Neptune autonomy simulator.Comment: 2 pages, ICMI'17, 19th ACM International Conference on Multimodal
Interaction, November 13-17 2017, Glasgow, U
The Impact of Two Curricular Models on Motivation, Engagement and Achievement in Physical Educatio
The purpose of this study was to compare motivation, engagement and achievement in two teaching conditions; one focusing on a skill-drill-game approach, and the second using Sport Education. Forty high school students were randomly selected to participate in either a Sport Education season or a Skill-Drill-Game unit. Post intervention measures of student enjoyment/interest, effort/importance, perceived competence, and pressure/tension were obtained for both groups. A daily gauge of engagement was obtained through pedometry. A pre- and postintervention measure of aerobic fitness was used to assess achievement. ANOVAs indicated a significant difference between groups for effort/importance (p= .012) and enjoyment/interest (p= .005), but not for pressure/tension (p= .762) or perceived competence (p= .218). Three separate oneway ANOVAs indicated that the SEM group took significantly more steps than the SDG group during the introduction and skill practice phase of the season/unit, during the preseason/modified games phase, and also during the regular season/game play phase. ANOVAs indicated a significant difference between groups on both engagement (p= .005) and aerobic fitness (p= .048). The results of this study provide initial, but cautious support for the notion that participation in Sport Education moves students towards more autonomous forms of motivation, which in turn results in greater levels of engagement in classes. The results support Sport Education as a viable curricular model for teachers in order to promote engagement in physical education. The challenge now is to plan studies that formally test this notion, and also use more sophisticated measures of engagement that use both the dimensions of active involvement as well as emotional intensity and effort
Effect of current corrugations on the stability of the tearing mode
The generation of zonal magnetic fields in laboratory fusion plasmas is
predicted by theoretical and numerical models and was recently observed
experimentally. It is shown that the modification of the current density
gradient associated with such corrugations can significantly affect the
stability of the tearing mode. A simple scaling law is derived that predicts
the impact of small stationary current corrugations on the stability parameter
. The described destabilization mechanism can provide an explanation
for the trigger of the Neoclassical Tearing Mode (NTM) in plasmas without
significant MHD activity.Comment: Accepted to Physics of Plasma
Resistive MHD Transport Model for an RFP: Part II - Results
No. DE-FG02-91ER-54109. Reproduction, translation, publication, use and disposal, in whole or in part, by or for the United States government is permitted. Submitted for publication to Physics ofPlasmas
Resistive MHD Transport Model for an RFP: Part I - The Model
No. DE-FG02-91ER-54109. Reproduction, translation, publication, use and disposal, in whole or in part, by or for the United States government is permitted. Submitted for publication to Physics ofPlasmas
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