Certainly! To include key entities such as people, organizations, and places for entity-based ranking, you generally need to follow these steps:1. **Entity Extraction**: Use Named Entity Recognition (NER) to extract entities from your documents or dataset. Popular NER tools/frameworks include:
- SpaCy
- Stanford NER
- Hugging Face transformers (models fine-tuned for NER)
- Flair2. **Entity Normalization**: Normalize or link entities to canonical forms (e.g., "U.S." → "United States") to ensure consistency. You can use:
- Named Entity Linking (NEL) systems like DBpedia Spotlight, Wikifier, or REL
- Custom synonym dictionaries or knowledge bases3. **Feature Engineering for Ranking**:
- **Presence of key entities**: Binary or count features indicating if a document contains particular entities.
- **Entity frequency**: Number of times key entities appear in the document.
- **Entity importance**: Assign weights based on entity type or relevance.
- **Entity co-occurrence**: How often certain entities appear together.4. **Ranking Model Integration**:
- Incorporate entity features into your ranking model (e.g., learning-to-rank models like LambdaMART, RankNet).
- Use entity-based features alongside traditional IR features like TF-IDF, BM25 scores, or embeddings.5. **Query Expansion or Reformulation (Optional)**:
- Extract entities from queries and expand the query using related entities to improve recall.### Example Pipeline```python
import spacy
from sklearn.feature_extraction.text import CountVectorizer# Load NER model
nlp = spacy.load("en_core_web_sm")docs = ["Apple is looking at buying U.K. startup for $1 billion",
"San Francisco considers banning sidewalk delivery robots"]# Extract entities function
def extract_entities(text):
doc = nlp(text)
entities = [(ent.text, ent.label_) for ent in doc.ents if ent.label_ in ["PERSON", "ORG", "GPE"]]
return entities# Extract entities per document
all_entities = [extract_entities(doc) for doc in docs]
print(all_entities)
# Output: [[('Apple', 'ORG'), ('U.K.', 'GPE')], [('San Francisco', 'GPE')]]# Feature engineering: Convert entities to features (example: count vectorizer on entity text)
entities_texts = [" ".join([ent[0] for ent in ents]) for ents in all_entities]vectorizer = CountVectorizer()
entity_features = vectorizer.fit_transform(entities_texts).toarray()print(entity_features)
# Each row corresponds to a document, each column to an entity token count# Integrate these features into your ranking or ML model as additional input features
```If you share more about your ranking system or data format, I can tailor the integration example further!