This class represents a web service that can be used to access SimDM/Resource-s registered in for example a SimDB. The precise way in which the web service gives access to these results not specified in detail. It includes simple downloads, and services implementing standards such as SimDAL. 
SimDM/Service is related to SimDM/Resource and can be used for more general purposes than simply giving access to results of a single experiment. It may be a web service that can handle results of any experiment performed by a particular SimDM/Protocol, or give access to all resources in a SimDM/Project.

The main goal of introducing SimDM/Service in the model is so that users can find web services based on requests for specific tyes of simulations etc. For example users may wish to find web services giving access to hydro simulations of clusters of galaxies with particular properties.
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It is assumed that web services registerd in a SimDB are also registered in a Registry which will store the more detailed capbilitieis and other service metadata. Therefore such details are not introduced here.