|
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:
- Each entity has a distinct id.
- 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:
 | At 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. |
| It 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. |
| It 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. |
| To do id-based or attribute-based location of entities. |
| To provide navigation services. |
| To provide visual output of the physical state of the
active space. |
|
]
