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🏗️ System DesignID: query-understanding-pipeline

Query Understanding Pipeline

Query 理解、分词与意图分类
🎯Core Definition
The Query Understanding Pipeline (QU) is the front-end NLP intelligence hub of search engines and e-commerce portals that structurally decodes raw search intents within <5ms<5\text{ms} before physical indexing: 1) Normalization (punctuation stripping, case folding, unicode normalization); 2) Spelling Correction (edit distance, phonetic pinyin mapping, and n-gram LM correction); 3) NER & Term Weighting (extracting brands, categories, attributes, and computing information entropy weights); 4) Synonym Expansion & Rewriting (e.g., expanding 'Apple phone' to 'iPhone'); 5) Intent & Category Classification (predicting transactional, navigational, or informational categories with confidence logits).
💡Use Cases
E-commerce search bars (Amazon/Taobao), general web search (Google), and vertical enterprise documentation search.
Key Problems Solved
Raw search queries are ultra-short (2-3 words), noisy, typo-riddled, and ambiguous; QU translates unstructured queries into structured boolean query trees with category filters and weighted tokens, establishing the ceiling of retrieval accuracy.
🎯5 High-Frequency Exam Points
1
Detail Term Weighting algorithms calculating importance weights between core entity nouns and modifier adjectives?
2
Design low-latency C++ inference acceleration for Transformer sequence-labeling NER models identifying e-commerce entities?
3
Explain the two-stage Query Spelling Correction architecture: Trie/phonetic candidate recall followed by n-gram/LM re-scoring?
4
How does synonym expansion prevent over-generalization via context-aware disambiguation (e.g. 'Apple' as fruit vs tech giant)?
5
How does Category Prediction enforce hard category filtering or soft boosting in e-commerce search to prevent irrelevant results?
Updated 2026-08-14
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