วันพุธที่ 7 สิงหาคม พ.ศ. 2567

World of NLP

 https://kinoshita.eti.br/2017/06/03/natural-language-processing-and-natural-language-understanding.html

https://en.m.wikipedia.org/wiki/Natural_language_processing













Feature extaction includes vectorization using Bag of word, word2vec, TF-IDF.


NLP model developing steps by ChatGPT:

To develop an NLP model using the terms provided, the process generally follows these steps:

1. **Data Collection**: Gather and prepare a dataset of text that will be used for training and testing the NLP model.

2. **Tokenization**:

   - **Explanation**: Split the text into smaller units called tokens, which can be words, subwords, or characters. 

   - **Purpose**: Tokenization allows the model to process and analyze text at a granular level.

   - **Example**: "The cat sat on the mat." becomes ["The", "cat", "sat", "on", "the", "mat"].

3. **Stop Words Removal**:

   - **Explanation**: Remove common words that have little meaning on their own, such as "the," "is," and "and."

   - **Purpose**: Reduce noise in the data, focusing the model on more meaningful words.

   - **Example**: After removal, ["The", "cat", "sat", "on", "the", "mat"] might become ["cat", "sat", "mat"].

4. **Stemming**:

   - **Explanation**: Reduce words to their root form by removing suffixes (e.g., "running" → "run").

   - **Purpose**: Simplify words to a common base form, reducing vocabulary size.

   - **Example**: "running", "runner", "ran" all stem to "run".

5. **Lemmatization**:

   - **Explanation**: Similar to stemming, but it reduces words to their base or dictionary form, known as the lemma, considering the context.

   - **Purpose**: Ensure words are reduced to their meaningful base form, which may differ based on context.

   - **Example**: "better" → "good", "running" → "run".

6. **Feature Extraction**:

- **Explanation**: Convert tokens into numerical features that the model can understand.

- **Methods**:

  - **Bag of Words (BoW)**: Represents text by the frequency of words in the document.

  - **TF-IDF (Term Frequency-Inverse Document Frequency)**: Adjusts the frequency of words by their importance across documents. (https://bdi.or.th/big-data-101/tf-idf-1/)

  - **Word Embedding**: An advanced method that transforms words into dense vectors capturing semantic relationships between words. Common methods include Word2Vec, GloVe, and FastText.

- **Purpose**: Transform text data into a format suitable for modeling, whether through simple frequency counts or more complex vector representations.

7. **Modeling with Deep Learning Algorithms**:

   - **Explanation**: Use deep learning techniques to build the NLP model.

   - **Purpose**: Leverage complex neural networks to capture patterns and relationships in text data.

   - **Common Models**:

     - **RNN (Recurrent Neural Network)**: Suitable for sequence-based tasks like text generation.

     - **LSTM (Long Short-Term Memory)**: An advanced form of RNN that handles long-term dependencies.

     - **Transformer**: State-of-the-art model architecture for NLP tasks (e.g., BERT, GPT).

8. **Model Training**:

   - **Explanation**: Train the deep learning model using the processed text data.

   - **Purpose**: Optimize model parameters to minimize error and improve accuracy.

9. **Evaluation**:

    - **Explanation**: Assess the model's performance on a validation set.

    - **Purpose**: Ensure the model generalizes well to unseen data.

10. **Deployment**:

    - **Explanation**: Integrate the trained model into a production environment.

    - **Purpose**: Make the model available for practical use.

11. **Monitoring and Maintenance**:

    - **Explanation**: Continuously monitor the model's performance and update it as needed.

    - **Purpose**: Ensure the model remains accurate and relevant over time

Example implementation of ChatBot using LSTM

https://medium.com/@newnoi/%E0%B8%A1%E0%B8%B2%E0%B8%AA%E0%B8%A3%E0%B9%89%E0%B8%B2%E0%B8%87-chatbot-%E0%B9%81%E0%B8%9A%E0%B8%9A%E0%B9%84%E0%B8%97%E0%B8%A2%E0%B9%86-%E0%B8%94%E0%B9%89%E0%B8%A7%E0%B8%A2-machine-learning-lstm-model-%E0%B8%81%E0%B8%B1%E0%B8%99%E0%B8%94%E0%B8%B5%E0%B8%81%E0%B8%A7%E0%B9%88%E0%B8%B2-part1-6230eac8d1f8

https://medium.com/@newnoi/%E0%B8%AA%E0%B8%AD%E0%B8%99%E0%B8%84%E0%B8%AD%E0%B8%A1%E0%B8%9E%E0%B8%B9%E0%B8%94%E0%B9%81%E0%B8%9A%E0%B8%9A%E0%B9%84%E0%B8%97%E0%B8%A2%E0%B9%86-%E0%B8%94%E0%B9%89%E0%B8%A7%E0%B8%A2-machine-learning-model-part2-2a1609af1bd7