Functional Requirements & CHIL Cooperative Information System Software Design

ion SituationModel <<singleton>> Persistence <<singleton>> Tracker Relation Situation ModelAPI Figure 6-9 Situation Modelling architectural classes. The roles of these classes are as follows: • Abstraction models entities. Examples include Person, Whiteboard, Table and Meeting. • Relation models a predicate (truth function) computed over one or more entity. Examples include At-Door(E1), In-Front-Of(E1, E2), Sitting(E1). • Roles designate the specific entities within the scene and associate them to potential actions and events. Examples are Lecturer, Audience History is maintained by recording the evolution of the situation within the network of situations so that chronological evolution can be queried. Cooperative Information System Software Design Version: 1.0 14-July-2004 Page 81/114 © CHIL Fraunhofer IITB, IBM, INRIA, KTH, RESIT/AIT, UKA/IPD The SituationModel is the main point of entry, enabling adding, querying and listing of objects in the model. It also enables searching for a particular type of objects, as for example looking for the current list of person objects in the situation model. Both Abstractions and Relations contain a set of attributes. These attributes may have an associated probability, and will vary in time. All the objects that will be modelled will have to satisfy the API of their base class. With the current set of use cases, we envision the following hierarchy: Cooperative Information System Software Design Version: 1.0 14-July-2004 Page 82/114 © CHIL Fraunhofer IITB, IBM, INRIA, KTH, RESIT/AIT, UKA/IPD Abstraction Relation Tracker FixedArtefact Whiteboard Table Chair MobileArtefact PDA Phone Person Meeting