Ask HN: How to search for science research jobs in Europe?

I am a graduate student in the U.S. nearing the completion of my master's degree in applied mathematics. I am looking for jobs at the master's degree level that involve working on large data sets, doing machine learning, scientific computing, etc. I don't want to be a software developer, per se, but don't mind doing software development among other scientific tasks.

For comparison, I used to work at MIT Lincoln Laboratory as an assistant radar analyst. It was a very very good mix of theoretical work, algorithmic development, and plain software development. I'm looking for similar institutions in Europe that are looking to hire full-time employees at the master's degree level. I've considered CERN (and may still apply there) but it appears to be either too much purely experimental physics or plain software development for me.

How do I locate these kinds of institutions, and what processes should I undertake to find such a job in Europe? What kinds of things should I look for in terms of job security, visa issues (I am only a US citizen), etc? I have worked for an extended time in Paris once before and loved living there (it was as a visiting research assistant as part of my current grad program). I'm looking to replicate that experience but in a full-time, non-student position.