A method for inferring a relationship between a first user and an area is disclosed, where the user is associated with one or more user devices. The method comprises retrieving event records having user device information corresponding to the user devices, and inferring, based on the event records, a relationship between the user and the area. A method for determining the presence of users at a location of a plurality of locations organised in a hierarchical structure is also disclosed. The method comprises receiving an indication of a location selected from the hierarchical structure, determining nodes associated with the selected location, retrieving event records from each node, and determining, based on the retrieved records, a number of users located at the selected location.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method for inferring a relationship between a first user and an area, the first user associated with one or more first user devices, wherein one or more nodes are capable of serving user devices located within said area, the method comprising: retrieving a first subset of a plurality of event records, wherein each event record corresponds to an event in a node and comprises user device information, time information, and location information, the first subset comprising one or more event records having user device information corresponding to the one or more first user devices; and inferring, based on one or more of the user device information, time information and location information associated with the retrieved events, a relationship between the first user and the area. 2. The method of claim 1, further comprising storing the relationship in a data store. 3. The method of claim 1, wherein inferring a relationship comprises: filtering the first subset to produce a second subset, the second subset comprising event records of the first subset having time information relating to a time between a first time and a second time; determining an average and a standard deviation for each location having at least one corresponding event record in the second subset; and inferring the first location for the user based on the average and the standard deviation for each location. 4. The method of claim 3, wherein the first time is a day time and the second time is a night time, and inferring a relationship between the user and the location comprises recording that the location is a work location for the user. 5. The method of claim 3, wherein the first time is a night time and the second time is a day time, and inferring a relationship between the user and the location comprises recording that the location is a home location for the user. 6. The method of claim 1, wherein inferring a relationship comprises for each location corresponding to the location information in at least one record in the first subset: calculating the number of records having location information relating to the location; and inferring a relationship between the user and the location based on the number of records. 7. The method of claim 6, wherein inferring a relationship between the user and the first location based on the number comprises: if the number is greater than a first number, recording that the user is a site worker at the first location; if the number is less than a first number but greater than a second number, and if a work location for the user is the same as a home location for the user, recording that the user is a home worker at the first location; if the number is less than a first number but greater than a second number, and if a work location for the user is not the same as a home location for the user, and the first location is associated with the user, recording that the user is an internal visitor at the first location; and if the number is less than a first number but greater than a second number, and if a work location for the user is not the same as a home location for the user, and the first location is not associated with the user, recording that the user is an external visitor at the first location. 8. The method of claim 1, wherein the event records comprise charging data records generated at the node. 9. The method of claim 1, wherein the operation of a subsystem in a facility is automatically controlled based on the inferred relationship. 10. A computer having computer-executable instructions stored thereon which, when executed by a computer, cause the computer to perform the method of claim 1. 11. A method for determining the presence of users at a location of a plurality of locations organised in a hierarchical structure having a plurality of levels, said plurality of locations being part of an area, each level of the hierarchical structure being associated with an area type of the area, wherein a plurality of nodes are capable of serving user devices located within said area, the method comprising: receiving an indication of a first location selected from the hierarchical structure; determining a subset of the plurality of nodes associated with the selected first location, each of said subset of nodes capable of serving user devices located at the first location; retrieving, from each node in the subset of the plurality of nodes, one or more event records, each event record corresponding to a user device event at the associated node and comprising user device information, event information and location information; and determining, based on the retrieved records, a number of users located at said selected first location. 12. The method of claim 11, further comprising storing the number of users in a data store. 13. The method of claim 11, further comprising: comparing the number of users at the first location to a predetermined user capacity for the first location. 14. The method of claim 11, wherein the area type comprises one of a zone, a floor or a building. 15. The method of claim 11, wherein determining a subset of the plurality of nodes associated with the selected first location comprises forming the subset from the node associated with the first location and descendants of the node. 16. A computer-readable medium having computer-executable instructions stored thereon which, when executed by a computer, cause the computer to perform the method of claim 11.