Office of Research Information Services

Office of the Chief Information Officer

SIdora Information Architecture

SIdora is based on the Flexible Extensible Digital Object Repository Architecture (Fedora). All information is managed as "information objects", each of which represents one unit of content. The objects provide an identity for the set of all components (content files, metadata files, policies, audit trails, etc.) that are associated with that unit of content. Each object can assert a formal relationship to any other object within the respository using the a link defined using the Resource Description Framework (RDF). In theory these relationships can also point to any compliant resource on any server in the world. This lets us build aggregations of related information objects that can represent complex resources, like research projects, and positions us to have our data particpate in a world-wide network of linked data, as it evolves.

The SIdora architecture is built upon the idea that there are two primary kinds of information object. Concept objects are a digital instantiation in a particular context of an idea,  a conceptual entity or as a digital surrogate for a physical object or entity. They are essentially descriptive metadata that provides a formal node in the creation of a context. Resource objects organize all of the components of a digital artifact, such as an image, video clip, tabular dataset, gene sequence, etc. Concept objects can have child concept objects, infinitely recursively and with relationships to any number of parents, while resource objects are the immediate children of one or more concept objects. The diagram below illustrates the model.

This means that a user of SIdora can construct an conceptual graph of description that provides an intellectual model that organizes digital resources in arbitrary ways. A concept object is only required to have a title in its metadata, which means that  a user can initially sketch out the context that is like a directory structure, later adding more metadata to each concept to enhance the graph to make it more of a rich database. This means that a outline of an intellectual model can be established quickly and used to organize resources as they are gathered, which is then built out as the resources are analyzed.

Though a project always starts with a project concept object, which establishes the root node of a tree which represents a project as a whole, it can quickly grow into a graph. A concept can be the child of more than one concept, as can a resource. For example, in an archaeology project a pot can be represented in a conceptual tree that captures the semantics of excavation, showing where the pot was found in a tomb, but simultaneously be in a tree that represents the analysis of pottery found in a whole site or in multiple sites. This allows for a particular context that represents the way that data is gathered, to coexist with multiple simultaneous contexts that represent that represent different lines of analysis for the same set of data.