{
  "model": {
    "architecture": "ContextualizedLemmatizer (character-level Transformer encoder-decoder with joint UPOS head; run context-free at inference)",
    "d_model": 512,
    "nhead": 8,
    "num_encoder_layers": 4,
    "num_decoder_layers": 4,
    "num_sentence_layers": 2,
    "dim_feedforward": 1024,
    "dropout": 0.15,
    "positional_encoding": "sinusoidal",
    "char_vocab_size": 140,
    "num_pos_tags": 18,
    "max_word_length": 50,
    "num_parameters": 26514078
  },
  "training": {
    "condition": "corpus-only (YCOE)",
    "training_instances": 84050,
    "dev_instances": 10506,
    "test_instances": 10507,
    "split": "80/10/10 random, seed 42",
    "epochs": 80,
    "batch_size": 24,
    "gradient_accumulation_steps": 3,
    "effective_batch_size": 72,
    "optimizer": "AdamW",
    "weight_decay": 0.01,
    "learning_rate": 0.00015,
    "lr_schedule": "cosine annealing with warm restarts (SGDR)",
    "lr_range": [1e-05, 0.00015],
    "num_cycles": 4,
    "cycle_peak_epochs": [22, 41, 58, 74],
    "warmup_fraction": 0.05,
    "label_smoothing": 0.15,
    "pos_loss_weight": 0.2,
    "early_stopping_patience": 20,
    "best_epoch": 74
  },
  "data_augmentation": {
    "type": "character-level, Old English spelling variation",
    "operations": [
      "substitution (þ<->ð, æ<->a/e, i<->y)",
      "deletion (words > 2 chars)",
      "adjacent-character swap",
      "duplication"
    ],
    "probability_per_word": 0.2,
    "reapplied_each_epoch": true
  },
  "performance": {
    "dev_lemma_accuracy": 0.6868,
    "test_lemma_accuracy": 0.6758,
    "test_pos_accuracy": 0.8275,
    "correct_lemmas": 7101,
    "correct_pos": 8695,
    "total_test_samples": 10507
  }
}