archives

The original appearance of this entry was in Danny Weitzner - Open Internet Policy

A group of Princeton University students have just launched an effort to expose privacy risks in the operation of the campus network. They’ve shown that each user’s username is publicly visible to anyone through a reverse DNS lookup. I hope the Princeton IT group will fix this but wonder how many other local networks are configured this way.

(One quibble: I found it ironic that the web site put up by these students fails to post it’s own P3P policy (the one Web standard for informing users about site privacy policies) and doesn’t even have a human-readable privacy policy. I hope they’ll fix both of these privacy gaps.)

Our RSS feed is plaintext, so when it's syndicated in Planet RDF and the like, there are no links or pictures or even paragraph breaks.

From #swig discussion, I gather that the state-of-the-art is to use nasty escaped markup, but I'm not up for that. The RDF Core WG didn't spend 18 months getting the details of parseType="Literal" right for nothing, did we?

I don't know if there are drupal modules available that Do The Right Thing, and due to my PHP angst I don't really want to know. But maybe there's a motivated student out there... ?

In the W3C formalized digital library, we supplement the dublin core with a formal model of the W3C Rec-track process and various other schemas.

They were orginally written in N3, and published as RDF/XML. We've tried using CSS to make the RDF/XML browser-friendly, but in N3, it's a royal pain to make a hypertext link from a description of a class or a property, and I'm not even sure it works at all with RDF/XML+CSS. I pretty much prefer using XHTML as the source of most of the knowledge I record, and now that GRDDL is maturing, I revisited my work on representing RDF schemas in XHTML.

And since converting from N3 to XHTML is something the machine can do for me, I'd hate to do it any other way.

To convert the class relationships to an indented list, I want

• all the implicit class relationships, not just the stated ones, but
• only the direct super/subclass relationships, not the indirect/redundant ones

My working solution, classReport.n3, uses this rule to get the class relationships implied by RDFS semantics:

@forAll C, C2, SCHEMA, X, P, V.

{
  SCHEMA a Schema; copy ?SC.
  (?SC.log:semantics
   <http://www.w3.org/2000/10/swap/util/rdfs-rules>.log:semantics
   <classDef.n3>.log:semantics
  ).log:conjunction
    log:conclusion ?F
} => { SCHEMA rdfsClosure ?F }.

... and here are the rules for making the tree:

{
  SCHEMA a Schema; rdfsClosure ?F.
  ?F log:includes { C a rdfs:Class }.
  C log:racine SCHEMA.
  ?F log:notIncludes {
    C rdfs:subClassOf [ rdfs:isDefinedBy SCHEMA].
  }.
} => { SCHEMA root C }.

# direct subclasses
{ ?S a Schema; rdfsClosure ?F.
  ?F log:includes { C rdfs:subClassOf C2 };
     log:notIncludes { C rdfs:subClassOf [ rdfs:subClassOf C2 ] }.
} => { C rdfs:subClassOf C2 }.

I use a utility classDef.n3 to connect classes to schemas:

{ ?C a rdfs:Class.
  ?C log:racine ?DOC
} => { ?C rdfs:isDefinedBy ?DOC }.

Note this only works if you use the HashURI pattern.

I'm pretty happy with the result so far, though I've only got classes, their labels, and the subclass relationships, so far: