QED: Groupon's ETL management and curated feature catalog system for machine learning. - Derrick C. Spell; Ling-Yong Wang; Richard T. Shomer; Bahador Nooraei; Jarrell Waggoner; Xiao-Han T. Zeng; Jae Young Chung; Kai-Chen Cheng; Daniel Kirsche (IEEE BigData, 2016)