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Metamodels Introduction: The Resource-Event-Agent (REA) framework has been designed for representing and reasoning about economic exchanges. The basic REA pattern models an exchange by three components: the events of the exchange, the resources that are exchanged, and the participating agents. In order to obtain a resource an agent must give up some other resource. Therefore, an economic exchange always consists of two corresponding events, e.g. a purchase and a payment. This figure shows the basic REA pattern, where the relationship between events in an exchange is modelled by the association "duality" (the figure is taken from [Geerts,McCarthy2000]). An extended version of the REA pattern is shown in this figure (also taken from [Geerts,McCarthy2000]). It also shows commitments that are established, where a commitment is an obligation to perform an economic event some time in the future. An economic event is the transfer of an economic resource from one agent to another. The figure also makes a distinction between the operational level of day-to-day activities and objects and the knowledge level which describes groups of activities and objects. There are several papers on the REA framework. Two of the most important ones are listed below. The first is a classical paper from 1982, where the REA framework is introduced. The second is a recent paper discussing extensions to the original REA framework and putting the framework into the context of ontologies. REA has been used as one of the theoretical foundations of UMM. It is incorporated in the BRV (Business Requirements View). More information can be found at the home page of William E. McCarthy. Page prepared by Prof. Paul Johannesson, Royal Institute of Technology, Stockhom, Sweden. Links:
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