Persona Data Model 2.0
A natural, human person is represented as a graph of
p:Person entities (nodes, or vertices) interconnected by links (edges). Each node represents a different facet of the user (person). Each of these facets is held in a separate (graph) container called a context.
Each Person node is a set of attributes and values. These attributes may be simple literals (e.g. the user's first name) or they may be other entities (which we call complex attributes). These latter attributes are shown in diagrams a as links to other nodes.
Typically each node in the person graph is located in its own container call a Context. The root node lies in a special context (for each user) called the root context.
All of the main person entities can be reached by traversing links of the following kinds, (although other links may also exist (e.g.
In order to simplify the diagram below we follow a convention whereby the links are drawn between contexts whereas in reality the links are between the main
p:Person objects within each of these contexts. Further, these main person entities may well themselves have complex attributes (i.e. links to other entities). These have also been omitted.
Each regular context may have up to one associated template context (pointed to by p:template attribute). This template context may contain one or more of the following:
- so-called view information that describes how to logically organize a presentation interface for the associated regular context
- a p:Person subclass that has a set of mapping rules written in the Mapping vocabulary
- template information about how to dynamically create the associated regular context
- template information related to how to dynamically build so-called AppData contexts that are pointed to by the Person in the associated regular context
Each regular context is associated with up to one "control" context (linked to by h:context) that contains meta information such as:
- access control policy (e.g. read, write, append) for named external parties trying to access the regular context
- when the regular context was created and modified
Each regular context may be associated with up to one "twin" context (linked to by p:twin) that contains information about the person that is written to by one or more "other" parties in the interaction context. Its associated control context has access control policies that allow this/these other parties to write to this context. In a sense this context contains "what they say about you", whereas the regular context is roughly "what you say about you."
Representing Social Graphs
HDM defines a
h:relation complex attribute that is used in PDM to link one
Person node to another where each
Person node represents a different person. No symmetry is implied in this thus the statement (A
h:relation B) is akin to saying person A "knows of" person B.
Shown below are two social graph examples. One uses
foaf:knows links and and (unrelated to this) shows each node in its own context. The other uses
h:relation links and (unrelated) shows all person nodes in a single context. In the Work context we see that the user knows three colleagues but doesn't know how they know one another. In the Home & Family context we see that the user knows two people and that everyone knows one another. The
foaf:knows links are shown in both directions although logically this is redundant since
foaf:knows is what is a called a symmetric relation.
Nodes that represent the user are shown in purple. Nodes representing a person other than the user are shown in red.
To indicate that a person A "knows" person B where some level of reciprocated interaction between the parties is implied, we use foaf:knows.
Since foaf:knows is a broader concept than h:relation, foaf:knows is not a sub-attribute of h:relation. Thus if we had the statement "A h:relation B" then we might later add a second statement "A foaf:knows B" to add the stronger, broader (and symmetric) concept of "knowing."
HDM also defines
h:indeterminate link attribute on node A to indicates that its value(s) may or may not represent the same thing as is represented by A.
Consumers of the HDM may traverse
h:indeterminate attribute links and (despite ignoring all other links) traverse the entire graph of
Contexts may describe their contents in any vocabulary they wish so long as it builds on the Persona vocabulary. In the person graph example above all of the contexts except one describe their contents using the Persona Data Model (vocabulary) (shown as purple "PDM"s above). The exception is the managed i-card from Equifax which uses attribute (aka claim) URIs defined by the OASIS IMI TC and by the ICF's (Information Card Foundation) schema working group.
- Persona vocabulary - the main PDM data model that all contexts must use or build on
- Flat Persona vocabulary - a flattened, simplified subset useful for querying PDM-based data stores
@@@Need to rewrite. Old Persona Data Model Naming Notes
Imagine a root context containing a p:Person node locally named "me". This root node could have h:correlation links pointing to the root "me" nodes in two contexts, a web profile context, and a alice-staples context.
The web profile context might look like this:
The staples context (the profile of the user at staples.com) might look like this:
Rough notes; a bit long in the tooth: