Research Engineer
StumbleUpon is seeking a talented research engineer to help us improve the quality of our recommendation engine. This will involve research, analysis and implementation of algorithm and data elicitation methods that improve recommendation relevance as user feedback occurs. The data source: Explicit preference and markup data on 29M websites from over 7.5M websurfers. In total over 9 billion detailed stumble/rating/review records are available to analyze. If you are self-motivated and possess a Can-Do attitude, we want to talk with you!

Responsibilities:
* Research and implement changes to improve recommender quality
* Help invent new heuristics and algorithms for information distribution and content discovery
* Use statistical methods and machine learning to characterize user preference
* Investigate data mining and concept extraction strategies using classification and clustering
* Create visualizations for complex datasets
* Explore new data collection methods, both explicit and implicit
 
Qualifications:
* MSc or PhD in Computer Science or a related field
* 3+ years of applied research experience related to recommender systems, computational linguistics, data analysis, statistical learning methods, or search
* Experience with basic statistical methods such as modeling multi-variate distributions, hypothesis testing, bayesian inference, simulation modeling, time series analysis
* Experience working with large data sets (100GB+)
* Knowledge of text classification and clustering
* Knowledge of unsupervised learning methods a bonus
* Experience with distributed computation a bonus
* SQL experience required
* PHP, C++ experience strongly desired
* Strong people skills to work with other engineers
* Strong work ethic, diligent and reliable
* Proactive problem solving skills
* Adaptable and innovative
* Superb verbal and written communication skills
* Active Stumbler!

About StumbleUpon
StumbleUpon is a fast growing discovery company that enables people to find relevant and entertaining web content based on their personal interests. We have nearly 10 million registered users and our goal is to become the #1 way that people discover the best content on the web. We need talented people like you to help us get there!

StumbleUpon is a great place to work!
* Your contributions will make a big impact because we are a small team
* We offer competitive salaries and company equity
* Our generous benefits package covers employees at 100% and dependents at 80% with no waiting period
* Company-sponsored benefits include: medical, dental, vision, flex spending, Roth IRA/401(k), Life/AD&D insurance, short and long-term disability coverage, EAP services, three weeks PTO, eight company-paid holidays, commuter and gym membership reimbursements, and a myriad of voluntary benefits programs like Aflac and WageWorks
* We are located in SOMA San Francisco and are easily accessible via BART, CalTrain, MUNI and the Transbay Terminal
* Other employee perks like gym and transportation reimbursements, quarterly team outings, team lunches twice a week, company art program—and the opportunity to play in our company-wide pool and ping-pong tournaments