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Location Service

Currently, a certain physical knowledge of the building is assumed. The goal of the Location Service is to make this physical knowledge structured and organized in a hierarchy/graph.  Using GML, a complete geographic representation of the building is created.  This has the physical representation of the rooms, corridors, staircases, floors, etc.  Parts of bigger rooms may be represented in greater detail.

Each entity's information is stored in the smallest geographic feature which encompasses it fully.  The location detectors (IR sensors/badge detectors) would continuously update this information, which might include links to policy files.  There are two assumptions about the type of entities whose information is stored by the Location Service. They are:

  1. Each entity has a distinct id.
  2. The addition or removal of entities is an established and well-monitored process, irrespective of whether this process is explicit or implicit.

Uses of the Location Service/Physical Representation:

bulletAt the lowest level of abstraction, every Active Space corresponds to a physical space, so the Active Space id (used in the Trader while registering a service) is derived from its physical space.
bulletIt is an updated copy of the info about all the entities, so it can be used to repopulate a part of the Naming Service Tree.  If the information about services is also stored (subject to Assumption 2), then this re-population would be more effective.  However, the naming service provides an Active Space hierarchy which is actually a superset of the physical hierarchy.  Hence, it may not be possible to do a "complete" re-population of the Active Space hierarchy using the physical hierarchy.
bulletIt can be used effectively to achieve physical access control, e.g., when a user wishes to go to a particular destination, then all the policies en route can be sent to the security service along with the credentials of the user to determine whether he is allowed to do so.
bulletTo do id-based or attribute-based location of entities.
bulletTo provide navigation services.
bulletTo provide visual output of the physical state of the active space.