Bibliographic record
Abstract
Singular spectrum analysis (SSA), a linear univariate and multivariate time series technique, is essentially principal component analysis (PCA) applied to the time series and additional copies of the time series lagged by 1 to L-1 time steps. Neural network theory has meanwhile allowed PCA to be generalized to nonlinear PCA (NLPCA). In the paper, NLPCA is further extended to perform nonlinear SSA (NLSSA). First, SSA is applied to the data, then the leading principal components of the SSA are chosen as inputs to an NLPCA network (with a circular node at the bottleneck), which performs the NLSSA by nonlinearly combining all the input SSA modes into a single NLSSA mode. This nonlinear spectral technique allows the detection of highly anharmonic oscillations, as illustrated by a stretched square wave imbedded in white noise, which shows NLSSA to be superior to SSA and classical Fourier spectral analysis.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.002 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.005 | 0.002 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".