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Panos Alexopoulos

Developing NLP Solutions for Automatic Knowledge Graph Construction - Part 1

A Talk by Panos Alexopoulos (Head of Ontology, Textkernel)

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About this Talk


Knowledge graphs are increasingly becoming important in the AI world as an enabling technology for data integration and analytics, semantic search and question answering, and other cognitive applications.

However, developing and maintaining large knowledge graphs in a manual way is too expensive and time consuming. To accelerate and scale the process, methods and techniques from the areas of information extraction and natural language processing (NLP) can be very helpful.

In this masterclass we will take a deep dive into the tasks required for mining a knowledge graph from text, and we will implement basic and advanced NLP techniques for each of them, using open-source tools and resources.

Key Topics

  • Knowledge Graphs
  • Natural Language Processing

Target Audience

  • NLP practitioners who want to learn how to apply their craft for constructing knowledge graphs
  • Data Scientists and Machine Learning Engineers


By the end of this masterclass, the attendees will be able to: - Identify the main components of a knowledge graph and the stages involved in its development process. - Identify and formulate the NLP tasks involved in a knowledge graph mining project - Develop and evaluate methods for mining entities and relations using open-source software

Session Outline

Session 1: Introduction, Knowledge Graph Basics and Schema Definition (60mins)

  • Introduction (10 mins)
  • Knowledge Graph Basics (25 mins)
    • What are knowledge graphs and why we build them
    • Basic knowledge graph elements: entities, classes, individuals, relations
    • Knowledge graph representation: RDF Graphs vs Labeled Property Graphs
    • Knowledge graph development: lifecycle and approaches
    • Q&A
  • Defining a Knowledge Graph Schema (25 mins)
    • What a schema should include
    • Good and bad practices
    • Hands-on: Creating a knowledge graph schema with Protege
    • Q&A

Break (5 mins)

Session 2: Mining Entities (60mins)

  • Task formulation and approaches
  • Off-The-Shelf APIs vs Custom solutions
  • Hands-On: Mining entities with the Spacy Named Entity Extractor
  • Hands-On: Mining entities with the Spacy EntityRuler
  • Hands-on: Training a custom entity extractor in Spacy


The masterclass will be delivered in four 1-hour sessions, with one long break in between.

Each session will comprise a slide-based presentation of key topics and techniques, a hands-on demonstration of these techniques with relevant software, and a Q&A.


Intermediate - Advanced

Prerequisite Knowledge

  • Basic coding skills in Python and Jupyter notebooks
  • Familiarity with RDF/OWL or Labeled Property Graphs (e.g. Neo4J).

You need an access pass to attend this session: Diversity Access Pass or Full Access Pass apply

02 December 2021, 06:00 PM

06:00 PM - 08:00 PM

About The Speakers

Panos Alexopoulos

Panos Alexopoulos

Head of Ontology, Textkernel

Panos Alexopoulos has been working at the intersection of data, semantics, and software, contributing to building intelligent systems that deliver value to business and society since 2006. Currently Head of Ontology at Textkernel BV, leading a team of data professionals in developing and delivering a large cross-lingual Knowledge Graph in the HR and Recruitment domain