Re: [xdi] Thoughts in Modeling Personas in XDI

[Michael Schwartz <mike@gluu.org>]

Maybe I can shed some light on Gluu's implementation, and this could 
provide a concrete example.

This first kind of role Drummond is referencing is either an attribute of 
the person, in which case no special consideration needs to be given: it 
can be handled as any other attribute. Or its represented as a group. At 
Gluu, the organization, the person and the group all have i-numbers in our 
directory service. And the groupMembership is also referenced in the 
memberOf attribute of the person (so again, group membership basically 
looks like an attribute of the person).

Personas at Gluu are represented as sub-entries of the person. For 
example: inum=X1,ou=people,o=Y,o=gluu, where X1 is the inumber of the 
person and Y is the i-number of the organization. A person would be 
inum=z1,ou=personas,inum-X1,ou=people,o=Y,o=gluu. Furthermore, if we have 
a new person, X2, who is friends with X1, he may have a contact: 
inum=z2,ou=contacts,inum=X2,ou=people,o=Y,o=gluu. So it is possible to 
reference the person this information via several i-numbers.

I think if we map back the i-names to i-numbers, in some cases this may 
make the examples more concrete.

- Mike



>> Let me note that this concept of "persona" is most commonly referred to in
>> directory systems as a "role", i.e., =alice has the +salesperson role at
>> @company, and =alice has the +pitcher role at @sports.club.
>>
>> The second pattern is where =alice defines her own subcontexts that
>> represent different personas.
>
> Now, what is unclear to me is why these two patterns differ one from another. 
> Could we figure out any use case showing that a persona (second pattern) 
> cannot be thought at as a role of an individual in an organization or group 
> of members (first pattern)? I mean, from my PoV, +work, +baseball, +home, 
> etc. are all "contexts" in which =alice does play a "role": she is an 
> employer in her "work context", a player in her "baseball (team) context" and 
> a housewife in her "home context".
>
> Furthermore, to be precise, +work, +baseball, +home, are not proper instances 
> of contexts, rather they are different "categories" of contexts; e.g. =alice 
> is a +driver in @example.bus.company, not in +work; she is a +player in 
> @example.baseball.team, not in +baseball, she is +wife in @example.family, 
> not in +home, etc. Finally she is herself in her default context, which is, 
> simply, =alice.
>
> A third thought is about the usage of "numbered subcontext": $1 ("the first", 
> $2 ("the second"), $3 ("the third"), ... and $ (understood as "all of them") 
> itself are OK when applied to an identifier which is, by itself, a group - I 
> would say an array - i.e. an entity that naturally does contain members: 
> =alice+sister$1, @example.baseball.team+player$2, 
> @example.bus.company+driver$, @example.family+member$, etc. However, this is 
> less convincing when applied to identifiers identifying entities which are - 
> per se - unique, such as =alice.
>
> In other words, we should not have multiple =alice, rather we should probably 
> aim at having the very same =alice playing, as you said, different roles in 
> different contexts - or better - context instances.
>
> I might miss some important points here. If this is the case, please let me 
> know - the ideal would be to have a use case for this - If not, then I think 
> that this proposal is so simply that it could even succeed.. maybe.
>
> Best Regards,
> Giovanni
>
> Def. Quota "Drummond Reed" <drummond.reed@xdi.org>:
>
>> On Tue, Nov 16, 2010 at 12:50 PM, Giovanni Bartolomeo <
>> giovanni.bartolomeo@uniroma2.it> wrote:
>> 
>>> In order to speedly proceed toward closing some issues:
>> 
>> 
>>> During the call we discussed two alternatives for identifying different
>>> personas, one is the currently adopted in PDX
>>> 
>>> 
>>> http://wiki.oasis-open.org/xdi/PdxExample#Pattern.3ASubjectSuperset.28PersonaContext.29
>>> 
>>> and the second is the one I proposed here:
>>> 
>>> 
>>> http://wiki.oasis-open.org/xdi/XdiOne/AddressingAndGraphModel#A.24has.24aforqualifyingcontexts
>>> 
>>> my problem with the first option is that it causes semantic conflicts with
>>> the mereological interpretation of structured identifier (see hereafter
>>> reported excerpt from minutes):
>>> 
>>> 
>>> XDI adds a second feature to RDF, which is the ability of XRIs to express
>>>> structured identifiers reflecting the merelogical structure of the graph,
>>>> i.e., aggregation.
>>>> 
>>> 
>>> that's why I'm in favour of the second one. However, I've understood that
>>> the first pattern has been introduced for some issues related to the XRI
>>> resolution process - which I'm a bit less familiar with. Could you maybe
>>> guys provide some more details on this issue?
>>> 
>> 
>> Giovanni, in preparation for today's call, let me explain that I don't 
>> think
>> there is any conflict between the two patterns/models, i.e., that both 
>> work,
>> and both are part of the way personas can/will be modeled in XDI.
>> 
>> Let me first summarize the two patterns. The first one (illustrated in your
>> second link above), is where an individual, say =alice, can have different
>> "personas" by being placed inside different supercontexts.
>> 
>> @company=alice
>> @sports.club=alice
>> 
>> This pattern can be even more granular using tagged supercontexts.
>> 
>> @company+salesperson=alice
>> @sports.club+pitcher=alice
>> 
>> Let me note that this concept of "persona" is most commonly referred to in
>> directory systems as a "role", i.e., =alice has the +salesperson role at
>> @company, and =alice has the +pitcher role at @sports.club.
>> 
>> The second pattern is where =alice defines her own subcontexts that
>> represent different personas. This one is trickier, because =alice can have
>> many subcontexts, and not all those subcontexts represent personas of
>> =alice. For example:
>> 
>> =alice+tel    ==> represents the collection of Alice's telephone numbers -
>> not a persona of alice
>> =alice+friend      ==> represents the collection of Alice's friends - not a
>> persona of alice
>> 
>> So the question is, how can =alice define the set of personas for which she
>> is the sole authority, not inside other authorities (like @company or
>> @sports.club)?
>> 
>> The pattern for doing this (illustrated in your first link above) is the
>> inheritance pattern, i.e., defining subcontexts of =alice that are by
>> definition instances of =alice. Following  the metagraph symbol proposal,
>> this uses the superclass/subclass operator, !. It also uses the subject
>> operator, $, to indicate that the subcontext is a new subject.
>> 
>> In this pattern (illustrated using i-names instead of i-numbers for
>> readability), =alice can create subcontexts that semantically assert they
>> are personas because they are each subclasses of =alice. Each of these
>> personas is identified as a numbered subcontext, e.g., $1, $2, $3, etc.
>> 
>> The XDI statements that create these subcontexts are:
>> 
>> =alice/$1/$  ==> creates =alice$1
>> =alice/$2/$  ==> creates =alice$2
>> =alice/$3/$  ==> creates =alice$3
>> 
>> The XDI statements that asserts that these subcontexts are personas are:
>> 
>> =alice/!/=alice$1
>> =alice/!/=alice$2
>> =alice/!/=alice$3
>> 
>> Thus the semantics of =alice$[digits] where [digit] is a placeholder for 
>> any
>> number of digits is that it represents a persona of =alice defined by
>> =alice.
>> 
>> This doesn't yet answer the question of how =alice can identicate what type
>> of personas these represent, i.e., which one is her +home persona, her 
>> +work
>> persona, etc. These can be done with other XDI statements:
>> 
>> =alice/+home/=alice$1
>> =alice/+work/=alice$2
>> =alice/+baseball/=alice$3
>> 
>> Talk to you shortly,
>> 
>> =Drummond
>> 
>
>
>
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