Integrating Knowledge Graphs into the RAG Stack in 2024

Walid Amamou
UBIAI NLP
Published in
7 min readAug 13, 2024
Photo by Alina Grubnyak on Unsplash

In the rapidly evolving field of artificial intelligence, integrating various technologies to enhance performance and capabilities is a primary focus. One such integration is the combination of Knowledge Graphs (KGS) with the Retrieval-Augmented Generation (RAG) Stack. Knowledge Graphs provide a structured representation of information, capturing relationships and entities in a format that is both human-readable and machine-processable. The RAG Stack, on the other hand, enhances generative models by incorporating information retrieval processes, resulting in more accurate and contextually relevant responses.

This article explores the components and benefits of Knowledge Graphs, explains the workings of the RAG Stack, and offers a detailed guide on how to integrate these technologies to create a more powerful AI system.

Understanding Knowledge Graphs

Definition and Components

1.1. What are Knowledge Graphs?

Knowledge Graphs (KGS) are structured representations of information that capture relationships and entities in a format that is both human-readable and machine-processable. They are designed to integrate, manage, and retrieve knowledge from diverse data sources, creating a network of interconnected data points that represent real-world entities and their relationships.

1.2. Key Components of Knowledge Graphs

Entities: Entities are the primary nodes in a knowledge graph representing real-world objects, concepts, or things. Each entity has a unique identifier and attributes that describe its properties.

Relationships: Relationships (also called edges or links) connect entities in a knowledge graph, indicating how they are related to each other.

Attributes: Attributes (also called properties) are data points that describe specific characteristics of an entity.

Applications and Benefits

2.1. How are Knowledge Graphs Used in Various Domains?

Search Engines: Knowledge Graphs enhance search engines by providing more accurate and contextually relevant results. They enable search engines to understand the relationships between different pieces of information and provide users with comprehensive answers.

Example: Google’s Knowledge Graph powers its search feature, offering users direct answers to queries instead of just a list of links.

Healthcare: In healthcare, Knowledge Graphs integrate and organize medical information from various sources, facilitating advanced research, personalized treatment plans, and improved patient care.

Example: Knowledge Graphs can link symptoms to diseases, treatments, and medical research, aiding in diagnosis and treatment recommendations.

Finance: Financial institutions use Knowledge Graphs to analyze complex relationships between entities like companies, financial instruments, and market events. This helps in risk assessment, fraud detection, and investment strategies.

Customer Support: Knowledge Graphs power virtual assistants and chatbots, enabling them to understand and respond to customer inquiries with precise and contextually relevant information.

2.2. Benefits of Using Knowledge Graphs

  • Improved Data Interlinking
  • Enhanced Information Retrieval
  • Better Decision-Making
  • Scalability and Flexibility

Introduction to the RAG Stack

What is the RAG Stack?

The RAG Stack, or Retrieval-Augmented Generation Stack, is an advanced AI system designed to enhance generative models by integrating information retrieval processes. It combines two core components: retrieval and generation.

Retrieval: This component retrieves relevant information from a database or knowledge base based on the input query. Techniques such as keyword matching or semantic search are utilized to identify and fetch the most pertinent documents or data snippets.

Generation: This component employs natural language processing models, like GPT (Generative Pre-trained Transformer), to produce coherent and contextually appropriate responses. These models generate text that is informed by the retrieved data, ensuring that the output is both relevant and accurate.

How RAG Works:

The RAG Stack operates through a multi-step process:

  1. Input Query: A user submits a query or prompt that requires a detailed response.
  2. Retrieval Phase: The system processes the query to retrieve relevant documents or data points from a knowledge base or external sources.
  3. Augmentation Phase: The retrieved information serves as additional context provided to the generation model.
  4. Generation Phase: Equipped with the retrieved data, the generation model creates a detailed and informed response.

Applications of RAG:

Question Answering Systems: RAG is instrumental in developing sophisticated systems that provide precise answers by leveraging pre-trained models and external knowledge sources. For instance, Facebook’s RAG model can answer complex questions by retrieving relevant documents and generating well-informed responses.

Chatbots and Virtual Assistants: RAG enhances conversational agents, enabling them to deliver accurate and context-aware responses in real-time interactions. Customer support virtual assistants utilize RAG to retrieve specific product information or troubleshooting steps and generate tailored, helpful responses.

Content Generation: RAG assists in content creation by generating text that incorporates up-to-date information from reliable sources. Content creators can utilize RAG to produce articles, reports, or summaries that are informed and relevant.

This integration of retrieval and generation capabilities makes the RAG Stack a powerful tool across various applications, enhancing AI systems’ ability to understand and respond effectively to complex queries and tasks.

Integrating Knowledge Graphs into the RAG Stack

Integrating Knowledge Graphs into the RAG Stack significantly enhances its performance by leveraging structured data relationships. Here’s why this integration is important and the benefits it brings:

Why Integration is Important?

Integrating Knowledge Graphs into the RAG Stack enhances the system’s ability to provide accurate and contextually relevant information. Knowledge Graphs offer a structured representation of data, capturing complex relationships and entities. This structured data helps improve both the retrieval and generation processes in the RAG Stack.

Benefits of Integration:

1. Enhanced Retrieval Accuracy: Knowledge Graphs enable the retrieval component to find more relevant and precise information by leveraging structured relationships between entities. This capability ensures that the system can fetch more accurate data tailored to the user query.

2. Improved Generation Quality: By providing the generation model with well-organized and context-rich data, the quality and relevance of generated responses can be significantly improved. This ensures that the output is not only accurate but also contextually appropriate.

3. Contextual Understanding: Knowledge Graphs help the RAG Stack to better understand the context of queries. This deeper understanding leads to more accurate and context-aware responses, enhancing the overall user experience.

4. Better Decision-Making: The structured data in Knowledge Graphs supports better decision-making by providing a comprehensive view of the information. This holistic perspective enables more informed responses and enhances the system’s ability to support decision-makers.

Integrating Knowledge Graphs into the RAG Stack thus enhances its capabilities across retrieval, generation, contextual understanding, and decision-making, making it a robust solution for delivering accurate and relevant information in various applications.

Implementing the Integration: Step-by- Step Guide

  1. Install Necessary Libraries

Ensure all required libraries are available to create knowledge graphs, perform efficient searches, and generate responses.

!pip install networkx faiss-cpu transformers scikit-learn matplotlib

2. Create and Visualize a Knowledge Graph

Use networkx to create and matplotlib to visualize the knowledge graph, including entities and their relationships.

3.Integrate with a Retrieval System

Utilize faiss and scikit–learn for efficient retrieval of relevant nodes based on queries.

import networkx as nx
import matplotlib.pyplot as plt

kg = nx.DiGraph()

kg.add_node("Product_A", type="Product")
kg.add_node("Issue_1", type="Issue")
kg.add_node("Solution_1", type="Solution")
kg.add_edge("Product_A", "Issue_1", relation="has_issue")
kg.add_edge("Issue_1", "Solution_1", relation="has_solution")

pos = nx.spring_layout(kg)
plt.figure(figsize=(8, 6))
nx.draw(kg, pos, with_labels=True, node_size=3000, node_color="lightblue", font_size=10, font_weight="bold", arrowsize=20)
edge_labels = nx.get_edge_attributes(kg, 'relation')
nx.draw_networkx_edge_labels(kg, pos, edge_labels=edge_labels, font_color='red')
plt.title("Knowledge Graph")
plt.show()
import faiss
from sklearn.feature_extraction.text import TfidfVectorizer

node_data = {
"Product_A": "Product A is an advanced technology gadget.",
"Issue_1": "Issue 1 involves battery draining quickly.",
"Solution_1": "Solution 1 recommends updating the firmware."
}

vectorizer = TfidfVectorizer()
node_texts = [node_data[node] for node in kg.nodes]
X = vectorizer.fit_transform(node_texts)

index = faiss.IndexFlatL2(X.shape[1])
index.add(X.toarray())

def retrieve_nodes(query, top_k=2):
query_vec = vectorizer.transform([query]).toarray()
_, indices = index.search(query_vec, top_k)
return [list(kg.nodes)[i] for i in indices[0]]

query = "battery issue"
retrieved_nodes = retrieve_nodes(query)
print("Retrieved Nodes:", retrieved_nodes)

4.Generate Responses with a Pre-trained Model

Leverage transformers to use a pre–trained GPT–2 model, adjusting parameters for improved response diversity and quality.

from transformers import GPT2Tokenizer, GPT2LMHeadModel

tokenizer = GPT2Tokenizer.from_pretrained("gpt2")
model = GPT2LMHeadModel.from_pretrained("gpt2")

tokenizer.pad_token = tokenizer.eos_token

def generate_response(query):
retrieved_nodes = retrieve_nodes(query)
context = " ".join([node_data[node] for node in retrieved_nodes])
input_text = query + " " + context
inputs = tokenizer.encode_plus(input_text, return_tensors="pt", padding=True)
input_ids = inputs['input_ids']
attention_mask = inputs['attention_mask']
outputs = model.generate(
input_ids,
attention_mask=attention_mask,
max_length=100,
num_return_sequences=1,
no_repeat_ngram_size=2,
pad_token_id=tokenizer.eos_token_id,
temperature=0.7,
top_p=0.9
)
return tokenizer.decode(outputs[0], skip_special_tokens=True)

query = "How to fix battery issue?"
response = generate_response(query)
print("Response:", response)

These steps combine the structure and semantics of knowledge graphs with advanced text generation capabilities to provide accurate and contextual responses.

Conclusion

Integrating Knowledge Graphs into the RAG Stack significantly enhances the performance and accuracy of AI systems. By leveraging the structured relationships and rich contextual data provided by Knowledge Graphs, the RAG Stack can retrieve more relevant information and generate higher quality responses. This integration not only improves data interlinking and information retrieval but also aids in better decision-making and contextual understanding.

The step-by-step guide provided demonstrates how to implement this integration effectively, combining the strengths of both Knowledge Graphs and the RAG Stack to achieve superior AI performance. As AI continues to advance, such integrations will be crucial in developing systems that can handle complex queries and provide precise, context-aware information.

By integrating Knowledge Graphs, AI systems powered by the RAG Stack can excel in various applications, from question answering systems to chatbots and content generation tools. This enhancement marks a significant stride towards creating more intelligent and responsive AI technologies capable of meeting diverse user needs with accuracy and efficiency.

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Walid Amamou
UBIAI NLP

Founder of UBIAI, annotation tool for NLP applications| PhD in Physics.