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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 us-ability of traditional SQL databases. F1 is built on Spanner , which provides synchronous cross-datacenter replica-tion 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)
During the Summer of 1997-Nomad-a planetary-relevant 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)
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)
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)
We present a novel stereoscopic mapping system for use in post-nuclear accident operations. First we discuss a radiation shielded sensor array designed t o tolerate extended cumulative dose using 4 shielding. Next, we outline procedures to ensure timely, accurate range estimation using trinocular stereo. Finally, we review the implementation of a system for(More)
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