Overview of Text Representation
📜 Text representation is crucial in NLP as it converts raw text into numerical formats.
🧠 Essential for machine learning models that require structured inputs.
Importance of Text Representation
🔑 Text is unstructured, needing transformation for ML/DL models.
📈 Retains context and meaning for better semantics.
🚀 Enhances model performance by reducing noise.
Types of Text Representation Techniques
📊 Traditional (Statistical) Approaches
📝 TF-IDF (Term Frequency-Inverse Document Frequency)
📝 Document Term Matrix (DTM)
📝 Topic Modeling (LDA, LSA, NMF)
🌐 Word Embedding-Based Approaches
🔤 Word2Vec (CBOW & Skip-Gram)
🔤 GloVe (Global Vectors for Word Representation)
🔤 FastText (Facebook’s Word Embeddings)
🔍 Contextual Embeddings (Deep Learning-Based)
🔠 ELMo (Embeddings from Language Models)
🔠 BERT (Bidirectional Encoder Representations from Transformers)
🔠 GPT (Generative Pre-trained Transformer)
Traditional Approaches Explained
📈 BoW emphasizes word frequency while ignoring order and semantics.
🔍 E.g., "NLP is amazing" vs "Machine Learning is fun" as data corpus.
Limitations of Bag of Words
❌ Loses crucial word order and meaning.
📏 Leads to high dimensionality and sparse matrices.
🚫 Fails to account for semantic similarity among words.
Understanding N-Grams
🗣️ An N-gram is a contiguous sequence of N words for text analysis.
📚 Types include Unigrams, Bigrams, Trigrams, and Higher N-grams.
Advantages of Using N-Grams
🔄 Helps improve context understanding in NLP.
🖥️ Essential for search engines and text prediction tasks.
📊 Enhances language modeling like Google Autocomplete.
TF-IDF Overview
📉 TF-IDF evaluates the importance of words within documents.
📊 TF determines word frequency, while IDF assesses rarity.
Application of TF-IDF
🔍 Useful for keyword extraction, search engine improvements, and text classification.
🔑 Affects document ranking based on term importance.
Information Retrieval Systems
📦 Focuses on accessing necessary information based on user queries.
🌐 Google Search is a well-known example of an information retrieval system.
Information Retrieval Models
📈 Various models exist like Boolean, Vector Space Model, Probabilistic Models, and Neural IR Models.
🔗 Each type has unique methodologies for retrieving relevant documents based on user queries.
Probabilistic Models
🔮 These models address uncertainties and rank documents based on relevance probability.
💡 Include Bernoulli and Binomial models as primary examples.
Conclusion
📖 Understanding text representation and information retrieval in NLP is essential for effective machine learning application.
🔑 Choosing the right techniques improves the accuracy of language processing tasks.