Revolutionizing Sentiment Analysis with Customized Transfer Learning | by Risenhoover Sherrill | Dec, 2023

This article was crafted with the assistance of an AI writer helper, ZAI, to provide you with an in-depth understanding of how to enhance sentiment analysis using transfer learning with TensorFlow and Hugging Face.

Photo by Debby Hudson on Unsplash

Transfer learning, often known simply as fine-tuning, is the technique of retraining a model on a smaller dataset by utilizing knowledge previously gained from a larger dataset. The focus here is on using a compact review dataset to fine-tune a pre-existing transformer model. We’ll dive into:

  • The advantages of a custom sentiment analysis model using transfer learning
  • Constructing a transfer learning model for sentiment analysis
  • Making accurate predictions and evaluating their accuracy
  • Saving and reusing a fine-tuned transfer learning model
  • Speeding up the training process for extensive datasets

Step 1: Advantages of Transfer Learning for Sentiment Analysis

Before we delve into the technicalities, let’s explore why transfer learning is beneficial for sentiment analysis:

  • It’s generally more accurate than lexicon-based methods like VADER or TextBlob.
  • It requires less data and computational resources compared to building a model from scratch.
  • Leveraging a pre-trained model often results in better prediction accuracy.
  • It’s more cost-effective than cloud sentiment analysis services and is customizable to specific domain data.
  • It offers more precise predictions for specialized domains when compared to zero-shot or pre-trained models.

Step 2: The Mechanics of Transfer Learning

Transfer learning involves modifying a pre-trained model’s final layer to suit a new task. In sentiment analysis, this means replacing the pre-trained BERT model’s original classification head with one that corresponds to sentiment labels (positive or negative). The process typically includes:

  1. Selecting a pre-trained model.
  2. Removing the original output layer and its associated weights.
  3. Initializing new weights for the sentiment analysis task.
  4. Retraining the new weights.

Step 3: Setting Up Necessary Python Libraries

To begin, we install and import the required libraries:

# Install libraries
!pip install transformers datasets

We’ll use pandas and numpy for data handling, train_test_split from sklearn for splitting the dataset, tensorflow and transformers for model creation, Dataset from Hugging Face for dataset formatting, and accuracy_score to evaluate model performance.

# Data processing
import pandas as pd
import numpy as np

# Train test split
from sklearn.model_selection import train_test_split

# Modeling
import tensorflow as tf
from tensorflow.keras.optimizers import Adam
from transformers import AutoTokenizer, TFAutoModelForSequenceClassification

# Hugging Face Dataset
from datasets import Dataset

# Import accuracy_score to check performance
from sklearn.metrics import accuracy_score

Step 4: Collecting and Reviewing Data

We gather the dataset from the UCI Machine Learning Repository, focusing on Amazon reviews. Here’s the step-by-step guide to download, unzip, and prepare your dataset for analysis. If using Google Colab, remember to mount your Google Drive and set the working directory to where the dataset resides.

# Mount Google Drive
from google.colab import drive

# Change directory
import os
os.chdir("drive/My Drive/contents/nlp")

# Print out the current directory

We read the dataset using pandas and examine its structure:

# Read in data
amz_review = pd.read_csv('sentiment labelled sentences/amazon_cells_labelled.txt', sep='\t', names=['review', 'label'])

# Take a look at the data

Amazon reviews for sentiment analysis —

Step 5: Splitting the Data

We split the dataset into training and testing sets, with 80% for training and 20% for testing, ensuring we have a balanced dataset for accurate model evaluation.

Step 6: Tokenizing the Text

Tokenization is the process of converting text into numerical tokens. These tokens can be words, parts of words, or even punctuation. We use the BERT tokenizer to perform this task, including padding shorter reviews with zeros for uniformity.

# Tokenizer from a pretrained model
tokenizer = AutoTokenizer.from_pretrained("bert-base-cased")

# Tokenize the reviews
tokenized_data_train = tokenizer(X_train.to_list(), return_tensors="np", padding=True)

Step 7: Crafting the Transfer Learning Model

Here, we load a pre-trained BERT model without the classification head, compile it with a loss function, optimizer, and metrics suitable for our sentiment analysis task.

# Load and compile model
model = TFAutoModelForSequenceClassification.from_pretrained("bert-base-cased", num_labels=2)

Step 8: Training the Model

We train our transfer learning model using the tokenized dataset, specifying batch size and number of epochs. As we progress, we can observe the model’s performance, which often exceeds 90% accuracy after only a few epochs.

Step 9: Making Predictions and Evaluating the Model

After training, we use the model to predict sentiments on our test dataset and then evaluate its accuracy, which typically yields very high accuracy rates.

Step 10: Saving and Reusing the Model

We save both the tokenizer and model to the disk, allowing us to reload and reuse them for future sentiment predictions.

Step 11: Handling Large Datasets

For large datasets, we convert our data to a Hugging Face arrow dataset, tokenize it, load the model, and prepare it using prepare_tf_dataset(). This approach is more memory-efficient and faster, especially when dealing with extensive data.

Throughout this article, we’ve explored how transfer learning can transform sentiment analysis, offering a customizable, efficient, and highly accurate approach. Whether you’re working with small or large datasets, the flexibility of TensorFlow and Hugging Face ensures that you can adapt to the nuances of your specific domain, providing insights that are both deep and relevant.

For more tutorials, check out the GrabNGoInfo YouTube Channel, website, and LinkedIn page. Happy modeling!

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