Data records containing one or more fields, which can be considered keys andor values, are received, and processed such that data values of records that contain key values of interest are aggregated together. The exhaust box includes means providing access to the upstream face of the particle filter. The plurality of Internet Protocol television video streams currently being displayed by the respective set-top box devices are displayed together with the universal resource locator on a display device. User devices may propose an origin and orientation or transformation data for a common coordinate system and exchange proposed coordinate system data to agree on a common coordinate system.