Rolf Hendriks

· Data Scientist • Washington, DC • rolf@rolfhendriks.net

Experienced software engineer with 20 years in game development, mobile development, and data science. I can combine the skillset of an engineer with the mindset of a designer to deliver polished experiences for users and clean code for developers.

What I Offer

  • Technical Excellence. 20 years in software engineering have taught me many details about code quality, testing, client/server architecture, localization, accessibility, and much more.
  • Visual Polish. I developed pixel-perfect designs as a game developer and app developer, and I apply the same level of visual precision to my data visualizations.
  • Innovation. I am a first-principles thinker who excels at developing novel solutions to existing problems.
  • Initiative. I can thrive in low-supervision environments and take ownership of tasks and projects.
  • No Fluff Design. All of my work adheres to the No Fluff Design philosphy.

Skills

Python
SQL
Pandas
Scikit-Learn
Matplotlib
Tableau
NLP
Keras
Jupyter Labs
VS Code

Career Highlights

  • Designed, developed, and architected SylvanSync - a digital solution that replaces thousands of paper + pencil based lessons in Sylvan learning centers nationwide
  • Delivered The Great Courses Plus Apple TV - a Netflix-like app for high-quality University lectures - on time with no known bugs and a high degree of polish
  • Proactively developed an organization-wide Blackboard custom UI library of branded components for Blackboard apps used by millions of students daily
  • Initiated an incident dashboard used organization-wide across Capital One to help troubleshoot customer-facing issues
  • Created novel physics-based particle effects for Uncharted: Drake's Fortune - an award-winning Playstation game franchise

    • Work Samples

    Presto!

    General Assembly
    SQL
    Python
    Pandas
    Matplotlib

    Presto! is a high-performance SQL-based book and music recommendation algorithm that I made as my final project for General Assembly's Data Science Bootcamp

    Achievements

    • Designed a high-performance general-purpose SQL product database
    • Ingested 8GB of book and album data from multiple sources
    • Enabled queries of millions of reviews in milliseconds
    • Created robust search capabilities handling a variety of special cases (diactritic insensitivity, product disambiguation, first/last name ordering insensitivity, and more)
    • Developed a product recommendation page mockup using matplotlib

    Matplotlib Business Card

    Matplotlib

    My business card is also an exercise in how to achieve pixel-perfect control over data visualizations using Matplotlib, including how to insert assets into a plot. This has been my goal ever since I first began using matplotlib, and is deceptively difficult to do.

    The Great Courses Plus (Apple TV)

    The Teaching Company
    Apple TV
    Swift
    Core Data
    RESTful JSON
    SQL

    Developed all features for the Apple TV version of Great Courses Plus - the Netflix of high-quality University lectures - and delivered a polished app on time with no known bugs. Then I implemented a complete redesign for the Wondrium rebrand.

    Achievements

    • Delivered polished and bug-free app in part by proactively querying the product SQL database for unusual data during development
    • Initiated the use of a shared backend between iOS and Apple TV

    Bb Student (iPhone)

    Blackboard, Inc.
    iOS
    Swift
    Core Graphics
    Localization
    Accessibility

    I was a key developer in the full software lifecycle of Blackboard mobile apps used by millions of college students daily to manage their course contents.

    Blackboard app screenshot Blackboard app screenshot

    Achievements

     

    SylvanSync (iPad)

    Sylvan Inc
    iOS
    Core Graphics
    RESTful JSON
    Usability Testing

    I consider this project my career highlight because of the exceptional level of ownership and innovation involved. SylvanSync replaced paper and pencil based instruction with iPad based learning for thousands of students in hundreds of Sylvan learning centers nationwide.

    As the developer, architect, and designer, I was present for the full product lifecycle and responsible for all details, beginning with proactively interviewing teachers and administrators before beginning design and development.

    Due to its non-public distribution, this project is not conducive to screenshots and videos.

    SylvanSync

    Achievements

    • Developer, architect, and designer of an iPad solution that replaced paper-and-pencil-based learning for thousands of lessons in Sylvan centers nationwide
    • Proactively visited learning centers to interview teachers and administrators before designing features
    • Designed a RESTful JSON client-server architecture while XML was the industry standard
    • Developed realistic handwriting and annotation tools by using a sophisticated custom Bezier spline algorithm
    • Innovated a scroll bar with built-in left-handed support and a unique gesture-based grading mechanism
    • More

    RHAnimator

    iOS
    Swift
    Core Animation
    Accessibility

    Quite possibly my best technical deep-dive, RHAnimator is an exploration of animation fundamentals from first principles, recreating and demonstrating various animation curves from scratch. RHAnimator is an excellent example of a carefully crafted developer API that combines flexibility and simplicity - two goals that are usually at odds with each other.

    Though this seems like an academic exercise, the impetus behind RHAnimator was to solve a real-world problem. I used a foundation similar to RHAnimator to bring rich liquid-like custom animations to life for Blackboard apps used by millions of students.

    Sliding Tiles

    Android
    Java

    This demo is a deep-dive on Android layout, interaction, and animation fundamentals. I included this unusual example in my portfolio to demonstrate transferability of skills. Despite being quite inexperienced in Android development, I was able to quickly adapt a user-centric iOS development philosophy to a new platform with this project.

    So if you have an engineerig project in mind that does not fit the specifics of my current tech stack, keep this example in mind.

    These are only a few of many examples of my work. See my Resume for a more complete and chronological list.

    Certifications and Awards