Wednesday, 8 July 2020

Graphistania 2.0 - Episode 7 - The one after the Covid-19 lockdown

Yes! We were able to record and publish another episode of our Graphistania podcast. It's been an amazing and turbulent couple of months - but before the summer holiday season really takes off we wanted to get this to you.

Wishing you a fantastic and relaxing time - and in the mean time enjoy this episode!

Here's the transcript of our conversation:

Monday, 29 June 2020

Executives of Belgian Public Companies - revisited!

Tuesday, 16 June 2020

What VAT Fraud Detection and Contact Tracing have in common

In the previous blogpost we already illustrated in some detail that the contact tracing graph that we built, has a lot of similarities with a product recommendation system graph. We focused on a the Person-Visit-Place triangle that we had built in our Contact Tracing Graph data model, and converted the red and yellow bits into a Person-Purchase-Product triangles.
There is of course another part to the contact tracing graph that is also very interesting: the Person-Meets-Person subgraph. We derived that graph from the original contact tracing graph, by assuming that if a Person had visited a Place at the same time as another person, they would have been likely to have had a meeting there. This Person-Meets-Person subgraph was the basis for most of our graph analytics.

Friday, 12 June 2020

What Recommender Systems and Contact Tracing have in common

With the Covid-19 pandemic raging in the past few months, I have had a lot of interesting conversations about the use of graph technology and how it could help the world be a better, safer, healthier place. At Neo4j, we even put in place a specific Graphs4Good program, helping out where we can. There's splendid research going on at, companies like Elsevier chipping in (and using Neo4j) as well, and I have tried to write up my humble thoughts on how Contact Tracing could really benefit from using graphs as well. See some of my recent posts published on this blog.

Looking at that work, however, I always had a the feeling that I was looking at an excellent example of something else: an excellent example of a great "graph problem". The contact tracing example is a great fit for a tool like Neo4j, and the reason why that is the case is basically because the problem that we are trying to solve with contact tracing (understanding the pandemic spread in our societies, predicting potential evolutions of the pandemic based on contacts between healthy and sick individuals, protecting the healthcare systems by managing the rate of spreading this way) is very much suited for analysis with graph technology. It is a domain where the links between people, the links between people and places, their visits, their meetings are the main important data entities that we need to look at. It's the connections that matter. It's the connections that are becoming the "equal citizens" in the dataset - and therefore we need to spend time and resources analysing it.

But of course I know one thing for sure: there are plenty of other cases that are like that, that are true "graph problems" and that could really benefit from a graph approach to solving it. We know that from all the Neo4j project that we have been running for years. So how do I demonstrate that? How do I show that Contact Tracing is essentially the same thing like a recommendation engine? Or another graph application that we have come to know and love. Let's explore that.

Tuesday, 9 June 2020

Creating a Contact Tracing Testbed with Neo4j and Faker

Over the past few weeks and months, I have been living through the Covid-19 pandemic like many others. It's not been easy - but at the same time I feel very fortunate to have been able to stay healthy, active, working, and connected. There's a lot of people out there that are a lot less fortunate, and my heart goes out to them.

On this blog, I have been writing about using graphs for Contact Tracing quite a bit. See 
Fortunately, these articles were very well received by the community - we have had a ton of discussions with a variety of different individuals, companies and governments about how to use this technology to prevent that the next lockdown would again require immobilising so many healthy people. If the pandemic's second wave hits, we all want people at risk / sick people to be separated from the healthy population, and manage the spread of the disease in this way. But all of that requires contact tracing to be effective and operational - which is not a trivial thing to do.

This is why I have been looking at creating a very easy to use testbed for Contact Tracing in Neo4j. I wanted to make it super easy for people to create synthetic contact tracing datasets, and then work with them to gain experience - valuable experience for the "real deal" when we have to manage that. That's what this post is about.

Tuesday, 28 April 2020

Contact tracing guide for the Neo4j Browser

Based on the past two blogposts on (Covid-19) contact tracing (see here for the posts, here for the movies), I thought it would be a good idea to pick up an old skill - to create a Browser Guide for Neo4j for people to look at this dataset example more easily. I did this a long time ago for my beergraph as well, so why not do it for the contacttracinggraph :) ...

About the Neo4j Browser and Browser guides

Here's what this is: with Neo4j, the native graph database, we always ship a default user interface called the "Neo4j Browser". It's a interactive application that communicates with the database, and that essentially allows you to fire of Cypher queries and look at / manipulate the contents of your database. Read up about it over here. Once you have done that you will realise that the Browser is actually more than that: it's also a great way for people to learn more about Neo4j, and has a built in mechanism to share "guides" to various topics. If you experiment a bit with the following commands:

A guided tour of Neo4j Browser
:play intro
Graph database basics
:play concepts
Neo4j’s graph query language introduction
:play cypher
The Movie Graph
A mini graph model of connections between actors and movies
:play movie graph
The Northwind Database
A classic use case of RDBMS to graph with import instructions and queries
:play northwind graph
you will get to see a number of topics that allow you to familiarise yourself with it really easily. Most of these guides are either built in or available for serving from a webserver. But: you can also develop these guides yourself. There's a really nice worked example over here, but the process really is dead simple:

Friday, 24 April 2020

(Covid-19) Contact tracing follow-up - demo movies

In my previous post I outlined the 4 different blogposts that I wrote about using the Neo4j Graph Database for Contact Tracing. Each of these posts is actually interesting in and of its own, and actually makes for a really nice demo of the capabilities in Neo4j. So I created those today - and put them on a Youtube playlist for you: