Machine Learning

Text Mining #1 Theory

grace21110 2023. 9. 4. 23:12
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Text Mining performs analysis tasks such as business intelligence and predictive analysis by establishing models and extracting information using machine learning, language understanding, and statistics. 

 

It is categorized in four different parts:

1) Text Classification (Text Categorization) : Text classification is like teaching a computer to understand and sort text into different categories or labels. Imagine you have a big pile of books, and you want to organize them into genres like fiction, science fiction, romance, and mystery. Text classification does something similar but with digital text data.

 

2) Sentiment Analysis : Sentiment analysis is the process of evaluating and categorizing the sentiment or emotional polarity conveyed in text, such as reviews, comments, social media posts, and other forms of written communication. It aims to determine whether the text expresses positive, negative, or neutral sentiments.

 

3) Summarization : Summarization is a technique for extracting important topics or central ideas within a text.

 

4) Clustering : Clustering a type of unsupervised learning technique used to group similar data points together based on certain characteristics or features, without the need for predefined labels or categories. Clustering is often used for data exploration, pattern recognition, and understanding the structure of the data.

 

 

# Process for Text Mining 


1) Data Collection : Gather the text data from various sources, such as websites, documents, social media, or databases. Ensure that the data is relevant to your analysis objectives.

2) Data Preprocessing : Clean the text data to remove noise and inconsistencies. Common preprocessing steps include:
     - Text Cleaning: Remove HTML tags, special characters, punctuation, and extra whitespace.
     - Lowercasing: Convert all text to lowercase to ensure consistency.
     - Tokenization: Split the text into words or phrases (tokens) for further analysis.
     - Stop Word Removal: Eliminate common words like "the," "and," "is," as they often don't carry meaningful information.
     -  Stemming or Lemmatization: Reduce words to their base or root form to treat variants as the same word (e.g., "running" and "ran" become "run").

3) Text Parsing : Analyze the structure of the text, such as sentence and paragraph boundaries, to understand the context and relationships within the data.

4) Text Exploration and Visualization : Perform exploratory data analysis (EDA) to gain insights into the data. Visualizations like word clouds, histograms, and word frequency distributions can help identify patterns and trends.

5) Text Representation : 
   - Convert the text data into a numerical format that machine learning models can work with. Common techniques for text representation include:
     - Bag of Words (BoW): Represent each document as a vector of word frequencies or term occurrences.
     - TF-IDF (Term Frequency-Inverse Document Frequency): Assign weights to words based on their importance in a document relative to the entire dataset.
     - Word Embeddings (e.g., Word2Vec, GloVe): Create dense vector representations of words that capture semantic relationships.

6) Feature Selection : Choose the most relevant features (words or phrases) to include in your analysis. This step can help reduce dimensionality and improve model performance.

7)  Text Analysis : Apply various text mining techniques to extract valuable information from the data. Some common methods include:
     - Sentiment Analysis: Determine the sentiment (positive, negative, neutral) of the text.
     - Topic Modeling (e.g., Latent Dirichlet Allocation): Discover topics or themes within the text data.
     - Named Entity Recognition (NER): Identify and categorize entities like names, dates, and locations.
     - Text Classification: Categorize text documents into predefined classes or categories.

8) Machine Learning Modeling : If your goal is prediction or classification, build machine learning models using the preprocessed and feature-engineered text data. Common algorithms include decision trees, random forests, support vector machines, and neural 

networks.

9) Model Evaluation : Assess the performance of your machine learning models using appropriate evaluation metrics, such as accuracy, precision, recall, and F1-score.

10) Interpretation and Visualization : Interpret the results of your analysis and use visualizations to communicate findings effectively.