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Классификация текста и анализ тональности

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Язык и знанияНачальный #05
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Полный текст статьи представлен на английском; заголовок и аннотация локализованы.

ЧТО ЭТО ЗА ВОЗМОЖНОСТЬ

Takes a piece of text and outputs its category — sentiment polarity, topic, intent or policy violation. The label set is fixed at training time, so it answers which class rather than what is said. A single text can carry several labels, and the model can also emit a probability distribution over the label set.

Как это устроено

Early systems paired bag-of-words with linear classifiers; fine-tuning a pre-trained encoder such as the BERT family later became the standard when labelled data is scarce. A classification head sits on top of the encoder and is trained with cross-entropy. With many labels and few examples, it can be recast as sentence-pair entailment or done zero-shot by prompting a large model.

Примеры продуктов

5

Связанные организации

Типичное применение

  • Sentiment polarity of reviews and public opinion
  • Spam and policy-violation filtering
  • Routing tickets by topic and priority
  • Intent detection to drive dialogue

Как её оценивают

F1
Harmonic mean of precision and recall; more trustworthy than accuracy under imbalance
ROC-AUC
Ranking quality, threshold-independent
Confusion matrix
Per-class error direction, to locate systematic bias

Границы и трудности

  • Under heavy class imbalance, minority classes are ignored while accuracy still looks high
  • Wording drift outside the training domain degrades predictions
  • Sarcasm, negation and double negation are often flipped, since the literal words point the other way

Концепции в основе