Model clustering and its application to water quality monitoring
Bibliographic record
Abstract
Abstract The classification of objects into groups where the objects within a group share a set of common traits is important in many areas of applications and particularly in environmental pollution studies. Consider the situation where variables are measured on different occasions for each of K objects, and the objective is to classify these objects into groups according to some common characteristics. The procedure introduced in this paper consists of two aspects: model fitting and clustering. The model fitting selects a family of models which is appropriate for the structure and nature of the available measurements, and then is performed for both individual and pooled datasets. The clustering starts with K models that represent the K objects and thus the similarity of the objects reduces to the similarity of their models. Since the models are members of the same family, the models similarity is defined as the equality of their parameters of interest. Here, we partition the parameter vector into two sub‐vectors corresponding to the interested parameters and ancillary parameters. The clustering will group together objects that have common interested parameters while allowing the ancillary parameters to be object specifics. The p‐value associated with the proposed model linking test is used as the similarity measure. Several grouping strategies are proposed like cluster peeling, pairwise combining, as well as a speeding technique called splitting‐and‐binding. A small simulation study is used to demonstrate the utility of the method. The paper concludes by presenting an environmental application where the interest is to classify E. coli bacteria according to their responses to antibiotic treatments. The data were collected bi‐weekly at several locations within three Canadian watersheds during 2005. Metric closeness in parameter space used by conventional method and likelihood closeness in model space employed by model clustering are discussed in this application. Copyright © 2008 John Wiley & Sons, Ltd.
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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 | 0.005 | 0.019 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.004 | 0.003 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.002 | 0.001 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.002 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
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".