Abstract: A world may be partitioned into a set of regions and sub-regions by the computer game system in a hierarchical manner, wherein the regions and sub-regions are arranged according to a hierarchy, each sub-region being encompassed by a higher-level sub-region or region, and two or more highest-level sub-regions being encompassed by a region. A location of a user of the computer game system along with one or more statistics associated with the user may be assigned to a smallest sub-region created in the hierarchical manner. A rank of the user may then be determined within a region or sub-region encompassing the smallest sub-region to which the user's location was assigned, wherein the rank is determined using the one or more statistics associated with the user. One or more users may then be notified of the rank.

Abstract: Methods for establishing a location-based leaderboard by a computer game system are disclosed. The world may be partitioned into a set of regions and sub-regions by the computer game system using a hierarchical spatial data structure, wherein the regions and sub-regions are arranged according to a hierarchy, each sub-region being encompassed by a higher-level sub-region or region, and two or more highest-level sub-regions being encompassed by a region. A location of a user of the computer game system along with one or more statistics associated with the user may be assigned to a smallest sub-region created by the hierarchical spatial data structure. A rank of the user may then be determined within a region or sub-region encompassing the smallest sub-region to which the user's location was assigned, wherein the rank is determined using the one or more statistics associated with the user. One or more users may then be notified of the rank.

Abstract: Methods for establishing a location-based leaderboard by a computer game system are disclosed. The world may be partitioned into a set of regions and sub-regions by the computer game system using a hierarchical spatial data structure, wherein the regions and sub-regions are arranged according to a hierarchy, each sub-region being encompassed by a higher-level sub-region or region, and two or more highest-level sub-regions being encompassed by a region. A location of a user of the computer game system along with one or more statistics associated with the user may be assigned to a smallest sub-region created by the hierarchical spatial data structure. A rank of the user may then be determined within a region or sub-region encompassing the smallest sub-region to which the user's location was assigned, wherein the rank is determined using the one or more statistics associated with the user. One or more users may then be notified of the rank.

Abstract: Systems and methods for providing back-up hydraulic power for aircraft are disclosed. A system in accordance with one aspect of the invention includes a hydraulic supply line, a hydraulic return line, and a hydraulic actuator coupled between the supply line and the return line. The system can further include a fluid energy storage device coupled in parallel with the hydraulic actuator between the supply line and the return line, and a first valve (e.g., check valve) coupled in series between the supply line and the fluid energy storage device. A second control valve can control the flow of fluid from the fluid energy storage device to the actuator. In particular embodiments, the fluid energy storage can be coupled to an actuator that deploys and retracts an aerial refueling device.