Abstract: A service arrangement system coordinates service providers who provide geographical location-based services to users. The location-based services may include transportation of users. For example, a service provider operates a vehicle to transport a user from an origin location to a destination location. To provide an engaging user experience and encourage users to continue using the services, the service arrangement system accurately and expediently determines the origin location and the destination location based on querying available data sources. The service arrangement system can use selection rules for multiplexing, fallback logic, or load-balancing to select a high quality data source from the available data sources.

Abstract: A service arrangement system coordinates service providers who provide geographical location-based services to users. The location-based services may include transportation of users. For example, a service provider operates a vehicle to transport a user from an origin location to a destination location. To provide an engaging user experience and encourage users to continue using the services, the service arrangement system accurately and expediently determines the origin location and the destination location based on querying available data sources. The service arrangement system can use selection rules for multiplexing, fallback logic, or load-balancing to select a high quality data source from the available data sources.

Abstract: A service arrangement system coordinates service providers who provide geographical location-based services to users. The location-based services may include transportation of users. For example, a service provider operates a vehicle to transport a user from an origin location to a destination location. To provide an engaging user experience and encourage users to continue using the services, the service arrangement system accurately and expediently determines the origin location and the destination location based on querying available data sources. The service arrangement system can use selection rules for multiplexing, fallback logic, or load-balancing to select a high quality data source from the available data sources.

Abstract: Fine-grained access control for querying a database with low overhead and safety plans. In a view placement approach, base relations of the query expression are replaced by views that are appropriate for the particular user. Information leakage via UDF pushing, exception processing, and error messages can be prevented by generating safe plans. An existing query optimizer can be modified to perform redundancy removal and safe plan implementation. Subsumption testing available in materialized view matching can be exploited by the query optimizer. Authorization inference is exploited to generate safe plans.

Abstract: Fine-grained access control for querying a database with low overhead and safety plans. In a view placement approach, base relations of the query expression are replaced by views that are appropriate for the particular user. Information leakage via UDF pushing, exception processing, and error messages can be prevented by generating safe plans. An existing query optimizer can be modified to perform redundancy removal and safe plan implementation. Subsumption testing available in materialized view matching can be exploited by the query optimizer. Authorization inference is exploited to generate safe plans.