Eric Rollins

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F1 is a distributed relational database system built at Google to support the AdWords business. F1 is a hybrid database that combines high availability, the scalability of NoSQL systems like Bigtable, and the consistency and usability of traditional SQL databases. F1 is built on Spanner, which provides synchronous cross-datacenter replication and strong(More)
Many of the services that are critical to Google's ad business have historically been backed by MySQL. We have recently migrated several of these services to F1, a new RDBMS developed at Google. F1 implements rich relational database features, including a strictly enforced schema, a powerful parallel SQL query engine, general transactions, change tracking(More)
In June and July 1997, Nomad, a planetary-relevant mobile robot, traversed more than 220 kilometers across the barren Atacama Desert in Chile, exploring a landscape analogous to the surfaces of the Moon and Mars. In this unprecedented demonstration, Nomad operated both autonomously and under the control of operators thousands of kilometers away, addressing(More)
OBJECTIVE Descriptive analysis of 30-day, all-cause hospital readmission rate patterns from 2007-2012. POPULATION Medicare FFS beneficiaries experiencing at least one acute inpatient hospital stay. METHODS Using Chronic Condition Data Warehouse claims, we estimate unadjusted, monthly, readmission rates for the nation, within the Dartmouth Hospital(More)
OBJECTIVE Descriptive analysis comparing changes in hospital inpatient readmissions to emergency department visits and observation stays that occurred within 30 days of an inpatient stay. POPULATION Medicare fee-for-service (FFS) beneficiaries that had at least one acute hospital inpatient stay. DATA SOURCE Using 100 percent of claims in the Chronic(More)
OBJECTIVE Potentially avoidable hospitalizations have been identified by experts as leading to poor health outcomes and costly care. Potentially avoidable hospitalizations are particularly common among full-benefit dual eligible beneficiaries. This paper examines potentially avoidable hospitalizations rates by setting, state, and medical condition, and the(More)
During the Summer of 1997 Nomad a planetaryrelevant mobile robot, was driven via satellite link for more than 125 miles in the Atacama Desert of Chile by novice operators in North America, demonstrating many technologies relevant to robotic exploration of the planets. An innovative \transforming" chassis was demonstrated which uses a simple linkage to(More)
We introduce a protocol for schema evolution in a globally distributed database management system with shared data, stateless servers, and no global membership. Our protocol is asynchronous—it allows different servers in the database system to transition to a new schema at different times—and online—all servers can access and update all data during a schema(More)
During June and July of 1997, a mobile robot named Nomad traversed 223km in the Atacama Desert of southern Chile via transcontinental teleoperation. This unprecedented accomplishment is primarily attributed to Nomad’s innovative locomotion design which features four-wheel/all-wheel drive locomotion, a reconfigurable chassis, electronically coordinated(More)
This paper discusses the challenge of achieving high bandwidth, distant range wireless communication from mobile robots by way of antenna tracking. In the case of robots traversing rough terrain at moderate speeds, tracking demands high slew rates and large motion ranges due to vehicle motion disturbances. Attaining tracking accuracy, particular with the(More)