Johannes Wilms, Developer in Vienna, Austria
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Johannes Wilms

Verified Expert  in Engineering

Data Scientist and Developer

Vienna, Austria

Toptal member since September 2, 2021

Bio

Johannes is a data scientist with a strong theoretical background gained through a PhD in physics and nearly a decade of industry experience in large-scale software engineering projects. He believes in the power of Agile software development to produce results quickly and iterate based on these results.

Portfolio

Novomatic AG
Python, Scikit-learn, Pandas, Spark, Hadoop, BigQuery, Google Cloud, Docker...
TNG Technology Consulting
Java, Oracle, HTML, JavaScript, Objective-C, Swift, Jira, eCommerce...

Experience

  • Numerical Modeling - 15 years
  • MATLAB - 15 years
  • Jira - 9 years
  • Pandas - 6 years
  • Python - 6 years
  • Scikit-learn - 6 years
  • Spark - 4 years
  • Google Cloud - 2 years

Availability

Part-time

Preferred Environment

Python, Visual Studio Code (VS Code), Confluence, Git, Jira

The most amazing...

...thing about a project is taking it live and seeing it run in production.

Work Experience

Senior Data Scientist | Data Scientist

2016 - PRESENT
Novomatic AG
  • Developed a game recommender system to be used in smartphone gaming apps.
  • Carried out analyses and developed predictive models for responsible gaming applications.
  • Studied and benchmarked models for sports betting predictions, exploring ways to incorporate external information sources to offer more competitive odds or lower operator risk.
  • Developed custom online aggregations of Kafka Streams to allow for real-time personalization, incentives, and insights.
  • Provided a wide range of in-house data science consulting in the form of analyses and visualizations.
  • Integrated data from various SQL and NoSQL sources into a BigQuery data warehouse and created self-service dashboards.
Technologies: Python, Scikit-learn, Pandas, Spark, Hadoop, BigQuery, Google Cloud, Docker, Scala, Apache Kafka, Numerical Modeling, Predictive Modeling, Dashboards, Kafka Streams, Recommendation Systems, Casinos & Gaming, Gambling

Senior Consultant | Software Consultant

2012 - 2016
TNG Technology Consulting
  • Worked on existing projects with more than one million lines of code.
  • Used Jira to support Scrum and Kanban workflows for feature development and bug fixing.
  • Supported a CRM system for 10 million+ customers and an eCommerce platform with $500 million+ in annual revenue.
Technologies: Java, Oracle, HTML, JavaScript, Objective-C, Swift, Jira, eCommerce, Customer Relationship Management (CRM), eCommerce UI, eCommerce UX, eCommerce Platforms, Mobile eCommerce, iOS, Android, Subversion (SVN), Telecom Equipment & Solutions

Experience

Recommender System Service

A back-end service providing new logic to an existing smartphone app that offered access to a large number of games. Based on observed user preferences, the service would be called in different places to recommend additional games for a user to try.

The service consisted of two components. The first component ingested playing data from a PostgreSQL database and generated or updated a model. Typically, this would happen daily because new games were added frequently.

The second component then used the model to serve recommendations in the form of a REST service that provided a number of ways to generate different recommendations for different contexts.

Everything was encapsulated into Docker containers and run on AWS infrastructure. Caching recommendations for performance reasons could be implemented in a straightforward way as a proxy in front of the REST service.

Real-time Personalization and Monitoring

Real-time events that describe the user experience arrive via Apache Kafka topics and are processed using Spark Structured Streaming in an on-premise Hadoop cluster.

Domain-specific aggregations of the events are used to further personalize the user experience, provide users with custom incentives, and implement real-time monitoring of what's happening on the platform.

Education

2007 - 2012

PhD in Physics

University of Vienna - Vienna, Austria

2001 - 2007

Diploma (MSc Degree Equivalent) in Physics

Technical University of Darmstadt - Darmstadt, Germany

2004 - 2005

Erasmus Study Abroad Year in Physics

KTH Royal Institute of Technology - Stockholm, Sweden

Skills

Libraries/APIs

Scikit-learn, Pandas

Tools

MATLAB, Jira, BigQuery, Tableau, Kafka Streams, Confluence, Git, Subversion (SVN), Miva Merchant

Languages

Python, C++, Java, HTML, JavaScript, Objective-C, Swift, Scala, SQL

Frameworks

Spark, Hadoop

Paradigms

REST

Platforms

Oracle, Docker, Apache Kafka, Kubernetes, Amazon Web Services (AWS), iOS, Android, Visual Studio Code (VS Code)

Storage

Google Cloud, PostgreSQL

Other

University Teaching, Numerical Modeling, eCommerce, Casinos & Gaming, Gambling, Customer Relationship Management (CRM), Predictive Modeling, Dashboards, Recommendation Systems, eCommerce UI, eCommerce UX, eCommerce Platforms, Mobile eCommerce, Telecom Equipment & Solutions

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