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(Related publications: [PUBLink] [PUBLink])

The confidence projection that an Object really exists is realized by using an ExistenceProjection variable, which is similar to the temporal StateProjection variables of SRCs, taking values between 0 and 1 at each time point (see the extensible object constraint Object).

The ExistenceProjection is not only dependent on Object-local features but on the whole world state. For example, it is improbable that there is a Door if the agent's Location is Park. Given these global conditions, an Existence Constraint must be linked to all Objects to be capable of accessing all relevant State Resources. To keep the linking costs reasonably low, only one Existence Constraint is responsible for maintaining all Objects' ExistenceProjections.

The Extensible Conventional Existence Constraint

The Structural Existence Constraint

The Existence Constraint must also ensure correct Object configurations. For example, an Object with an ObjectType of Door and a Nutritive Value State Resource gets a very poor ExistenceProjection. However, Objects do not have to be specified completely. For example, the Door's Color State Resource may not be important for a plan to open it.

The ExistenceProjection of an Object has an impact on the satisfaction of Task Constraints that have tasks connected to the Object. Using this mechanism, an appropriate temporally projected anchoring, i.e., a convenient correspondence between the plan's and the real world's objects (see [PUBLink] for a more detailed treatment of this topic), can be realized.

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Last update:
May 20, 2001 by Alexander Nareyek