janrenz.de

Nerd, Researcher, PhD Candidate

OpenSource projects

codeocean

The online coding platform used on openHPI https://github.com/openHPI/codeocean

xikolo-android

The android app of openHPI: https://github.com/openHPI/android-app

xikolo-ios

The iOS app of openHPI (WIP): https://github.com/openHPI/ios-app

mediathek

An android app for accessing and downloading ARD content (deprecated): https://github.com/jprberlin/mediathek1

Some code snippets

How to not recreate existings elements in Rails / Ruby

Lets assume you dont want to recreate some Element if it already exists.

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@ticket = Ticket.find_or_create_by!(ticket_params)
if @ticket.new_record?
  @ticket.save!
  # do something else
end

In my case i wanted to allow the creation if th e original element is more than 1 hour old.

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@ticket = Ticket.find_or_create_by!(ticket_params)
if @ticket.new_record? or @ticket.created_at < 1.hour.ago
  @ticket.save!
  # do something else
end

Get all records created or updated in a certain timespan

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Ticket.where(updated_at: (Time.now - 24.hours)..Time.now)

Publications

Paper

Renz, J., Staubitz, T., Pollack, J., & Meinel, C. (2014). Improving the Onboarding User Experience in MOOCs. EDULEARN14 Proceedings, 3931-3941.

Staubitz, T., Woinar, S., Renz, J., & Meinel, C. TOWARDS SOCIAL GAMIFICATION-IMPLEMENTING A SOCIAL GRAPH IN AN XMOOC PLATFORM.

Renz, J., Staubitz, T., & Meinel, C. MOOC TO GO.

Meinel, C., Willems, C., & Thomas Staubitz, J. R. (2014). Reflections on enrollment numbers and success rates at the openhpi mooc platform. Proceedings of the European MOOC Stakeholder Summit, 101-106.

Renz, J., Staubitz, T., Willems, C., Klement, H., & Meinel, C. (2014, April). Handling re-grading of automatically graded assignments in MOOCs. In Global Engineering Education Conference (EDUCON), 2014 IEEE (pp. 408-415). IEEE.

Staubitz, T., Renz, J., Willems, C., Jasper, J., & Meinel, C. (2014, April). Lightweight ad hoc assessment of practical programming skills at scale. In Global Engineering Education Conference (EDUCON), 2014 IEEE (pp. 475-483). IEEE.

Staubitz, T., Renz, J., Willems, C., & Meinel, C. (2014). Supporting Social Interaction and Collaboration on an xMOOC Platform. Proc. EDULEARN14, 6667-6677.

Online

Sicherheit durch Wissen: Dank MOOCs sicherer im Internet?: https://www.dsin-blog.de/dank-moocs-sicherer-im-internet