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Record W4385634287 · doi:10.1007/s43670-023-00065-7

Embracing off-the-grid samples

2023· article· en· W4385634287 on OpenAlex

Why this work is in the frame

A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.

affAt least one author lists a Canadian institution in the pinned OpenAlex snapshot.
fundA Canadian funder is recorded on the work.

Bibliographic record

VenueSampling Theory Signal Processing and Data Analysis · 2023
Typearticle
Languageen
FieldEngineering
TopicSparse and Compressive Sensing Techniques
Canadian institutionsUniversity of British Columbia
FundersPetrobrasNatural Sciences and Engineering Research Council of CanadaHess CorporationBG GroupConocoPhillips
KeywordsAlgorithmUndersamplingComputer scienceArtificial intelligenceCompressed sensing

Abstract

fetched live from OpenAlex

Abstract Many empirical studies suggest that samples of continuous-time signals taken at locations randomly deviated from an equispaced grid (i.e., off-the-grid ) can benefit signal acquisition, e.g., undersampling and anti-aliasing. However, explicit statements of such advantages and their respective conditions are scarce in the literature. This paper provides some insight on this topic when the sampling positions are known, with grid deviations generated i.i.d. from a variety distributions. By solving a square-root LASSO decoder with an interpolation kernel we demonstrate the capabilities of nonuniform samples for compressive sampling, an effective paradigm for undersampling and anti-aliasing. For functions in the Wiener algebra that admit a discrete s -sparse representation in some transform domain, we show that $${\mathcal {O}}(s{{\,\mathrm{poly\,\hspace{-2pt}log}\,}}N)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mi>s</mml:mi><mml:mrow><mml:mspace/><mml:mrow><mml:mi>poly</mml:mi><mml:mspace/><mml:mspace/><mml:mi>log</mml:mi></mml:mrow><mml:mspace/></mml:mrow><mml:mi>N</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math> random off-the-grid samples are sufficient to recover an accurate $$\frac{N}{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mfrac><mml:mi>N</mml:mi><mml:mn>2</mml:mn></mml:mfrac></mml:math> -bandlimited approximation of the signal. For sparse signals (i.e., $$s \ll N$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>s</mml:mi><mml:mo>≪</mml:mo><mml:mi>N</mml:mi></mml:mrow></mml:math> ), this sampling complexity is a great reduction in comparison to equispaced sampling where $${\mathcal {O}}(N)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mi>N</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math> measurements are needed for the same quality of reconstruction (Nyquist–Shannon sampling theorem). We further consider noise attenuation via oversampling (relative to a desired bandwidth), a standard technique with limited theoretical understanding when the sampling positions are non-equispaced. By solving a least squares problem, we show that $${\mathcal {O}}(N\log N)$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>O</mml:mi><mml:mo>(</mml:mo><mml:mi>N</mml:mi><mml:mo>log</mml:mo><mml:mi>N</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:math> i.i.d. randomly deviated samples provide an accurate $$\frac{N}{2}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mfrac><mml:mi>N</mml:mi><mml:mn>2</mml:mn></mml:mfrac></mml:math> -bandlimited approximation of the signal with suppression of the noise energy by a factor $$\sim \frac{1}{\sqrt{\log (N)}}.$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mo>∼</mml:mo><mml:mfrac><mml:mn>1</mml:mn><mml:msqrt><mml:mrow><mml:mo>log</mml:mo><mml:mo>(</mml:mo><mml:mi>N</mml:mi><mml:mo>)</mml:mo></mml:mrow></mml:msqrt></mml:mfrac><mml:mo>.</mml:mo></mml:mrow></mml:math>

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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)0.001
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: Simulation or modeling · Consensus signal: none
GenreCandidate signal: Empirical · Consensus signal: none
Teacher disagreement score0.936
Threshold uncertainty score0.624

Codex and Gemma teacher scores by category

CategoryCodexGemma
Metaresearch0.0010.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.002
Science and technology studies0.0000.000
Scholarly communication0.0000.000
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 head0.065
GPT teacher head0.306
Teacher spread0.241 · 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