Abstract: This disclosure describes a map-matching module that supports a Global Positioning System (GPS) and provides a user with a best match trajectory corresponding to GPS sampling points taken at a low sampling rate. The best match trajectory is based upon a spatial-temporal analysis.

Abstract: Techniques for improving complex database queries are provided. A determination is made whether to adopt a static or dynamic query execution plan for a received database query based on metrics. When a dynamic query execution plan is adopted, the database query is separated into query fragments. A plan fragment is generated for each query fragment and executed to generate feedback for the plan fragment. The feedback from the execution of each plan fragment is used to initiate query rewrite rules to simplify the corresponding query fragments. The rewritten query fragments are combined to generate the dynamic query plan.

Abstract: This disclosure describes a map-matching module that supports a Global Positioning System (GPS) and provides a user with a best match trajectory corresponding to GPS sampling points taken at a low sampling rate. The best match trajectory is based upon a spatial-temporal analysis.

Abstract: This disclosure describes a map-matching module that supports a Global Positioning System (GPS) and provides a user with a best match trajectory corresponding to GPS sampling points taken at a low sampling rate. The best match trajectory is based upon a spatial-temporal analysis.

Abstract: This disclosure describes a map-matching module that supports a Global Positioning System (GPS) and provides a user with a best match trajectory corresponding to GPS sampling points taken at a low sampling rate. The best match trajectory is based upon a spatial-temporal analysis.

Abstract: Techniques for improving complex database queries are provided. A determination is made whether to adopt a static or dynamic query execution plan for a received database query based on metrics. When a dynamic query execution plan is adopted, the database query is separated into query fragments. A plan fragment is generated for each query fragment and executed to generate feedback for the plan fragment. The feedback from the execution of each plan fragment is used to initiate query rewrite rules to simplify the corresponding query fragments. The rewritten query fragments are combined to generate the dynamic query plan.

Abstract: Techniques for providing a route based on route-oriented vehicle trajectories are described. This disclosure describes receiving GPS logs and extracting route-oriented vehicle trajectory content from the GPS log data to pertain to a single trip. Next, the process maps each route-oriented vehicle trajectory to a corresponding road segment to construct a landmark graph. A landmark is a road segment frequently visited by route-oriented vehicles. The process includes receiving a user query with a starting point and a destination point; searching the landmark graph for a sequence of landmarks with corresponding transition times and a least amount of travel time. Then the process identifies and connects sets of road segments between each pair of consecutive landmarks, and displays a route to a user with a nearest landmark to the starting point, other landmarks along the route, and another nearest landmark to the destination point.

Abstract: This disclosure describes a map-matching module that supports a Global Positioning System (GPS) and provides a user with a best match trajectory corresponding to GPS sampling points taken at a low sampling rate. The best match trajectory is based upon a spatial-temporal analysis.

Abstract: Techniques for providing a route based on route-oriented vehicle trajectories are described. This disclosure describes receiving GPS logs and extracting route-oriented vehicle trajectory content from the GPS log data to pertain to a single trip. Next, the process maps each route-oriented vehicle trajectory to a corresponding road segment to construct a landmark graph. A landmark is a road segment frequently visited by route-oriented vehicles. The process includes receiving a user query with a starting point and a destination point; searching the landmark graph for a sequence of landmarks with corresponding transition times and a least amount of travel time. Then the process identifies and connects sets of road segments between each pair of consecutive landmarks, and displays a route to a user with a nearest landmark to the starting point, other landmarks along the route, and another nearest landmark to the destination point.