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Record W2905739182

Bias Assessment and Reduction in Kernel Smoothing

2018· article· en· W2905739182 on OpenAlexaboutno aff
Wenkai Ma

Bibliographic record

VenueScholarship@Western (Western University) · 2018
Typearticle
Languageen
FieldComputer Science
TopicFace and Expression Recognition
Canadian institutionsnot available
Fundersnot available
KeywordsSmoothingComputer scienceReduction (mathematics)Kernel (algebra)StatisticsMathematicsArtificial intelligenceEconometricsCombinatorics
DOInot available

Abstract

fetched live from OpenAlex

When performing local polynomial regression (LPR) with kernel smoothing, the choice of the smoothing parameter, or bandwidth, is critical. The performance of the method is often evaluated using the Mean Square Error (MSE). Bias and variance are two components of MSE. Kernel methods are known to exhibit varying degrees of bias. Boundary effects and data sparsity issues are two potential problems to watch for. There is a need for a tool to visually assess the potential bias when applying kernel smooths to a given scatterplot of data. In this dissertation, we propose pointwise confidence intervals for bias and demonstrate a software tool to implement the confidence bands in practice. The effectiveness of the proposed bias assessment tool is demonstrated using simulated data and is illustrated by its application to classical data sets. To reduce the bias of LPR while keeping other good properties of it, as well as to mitigate the sparsity and boundary issues, this thesis extends the technique of double-smoothing from the local linear regression context to higher order local polynomial regression, with particular focus on local quadratic and local cubic regression. Double-smoothing is a technique that involves two levels of smoothing and is known to reduce bias in nonparametric regression while maintaining control over variance. What was not known is that the method is often sub-optimal when the bandwidths at both levels of smoothing are equal. In this thesis, we propose a simple method for obtaining the second-level smoothing bandwidth while using a cross-validation method for the first level. The proposed tools in this dissertation are employed to address real problems related to wildfire management: one is for modelling the time to initial attack using fire case records for the years from 1930 to 2012 in a Northeastern Ontario area. Another one is for the experimental results of burning debris as a randomized component in a firebrand spotting simulator

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame distilled prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: codex-gemma-dda1882f352aValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Observational · Consensus signal: Observational
GenreCandidate signal: Empirical · Consensus signal: Empirical
Teacher disagreement score0.015
Threshold uncertainty score0.793

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0010.001
Science and technology studies0.0000.000
Scholarly communication0.0000.003
Open science0.0010.000
Research integrity0.0000.000
Insufficient payload (model declined to judge)0.0000.000

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.137
GPT teacher head0.346
Teacher spread0.209 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one teacher head, not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designObservational
Domainnot available
GenreEmpirical

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations1
Published2018
Admission routes1
Has abstractyes

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