Fed-IT: Addressing Class Imbalance in Federated Learning through an Information- Theoretic Lens
Bibliographic record
Abstract
Federated learning (FL) is a promising technology wherein edge devices/clients collaboratively train a machine learning model under the orchestration of a central server. However, due to the inherent data heterogeneity among clients, local datasets on individual clients often exhibit class imbalance, i.e., samples from majority classes vastly outnumber those from minority classes. This imbalance significantly diminishes the performance of the trained model. To understand why, we first closely examine the output probability distribution clusters of the local deep neural networks (DNNs) in the probability space over the label set, and observe that for class imbalanced datasets, FL has two interesting phenomena: (1) dispersion problem-clusters corresponding to minority classes tend to disperse; and (2) gravity problem-clusters corresponding to minority classes are drawn toward those of majority classes. To overcome these two problems, we then introduce information quantities into FL, propose a new information theoretic loss function for FL, and develop a new FL framework called Fed-IT. It is shown that Fed-IT significantly outperforms previous counterparts, while maintaining client privacy.
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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 | 0.009 | 0.025 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.002 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.003 |
| Scholarly communication | 0.003 | 0.008 |
| Open science | 0.003 | 0.004 |
| Research integrity | 0.002 | 0.004 |
| Insufficient payload (model declined to judge) | 0.002 | 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".