FOAF

If FOAF is to support an online community, it is essential that the provenance of every piece of information be traceable.

Shows a FOAF description of me that contains a link to an acquaintance of mine.

The simplest way is to have participants register the URL of their FOAF file with a central service, which then does the aggregation.

The rest of this article describes FOAF's basic features and gives some pointers to current implementations and future considerations.

Liz Somebody would not form a solution, because she has a foaf: name but no foaf: depiction property, and needs both to match the query.

The FOAF vocabulary provides a useful means of managing information within communities.

Using it, he might create an FOAF file shown in Listing 5.

In Listing 3, you query for the foaf: phone, but a new graph is constructed with a different predicate in its place (wingerz: officephone).

Like creating your own Web pages, the creation of your FOAF data is decentralized and within your control.

Fortunately, FOAF's creators have come up with an alternative, the mbox_sha1sum property.

These questions and others are under consideration among the FOAF developers.

Use popular ontologies like FOAF whenever possible because common structures and vocabulary will facilitate data integration.

Instead, FOAF tools use digital signatures to associate an e-mail address with a document.

Also, be sure to check out Resources for more documentation and demonstrations of FOAF.

Link also serves as a useful way of separating FOAF descriptions into multiple files.

Theorizing aside, let's take a look at what form FOAF information takes.

Note that it is good practice to use existing predicates whenever possible; in this case, you use some vocabulary from the FOAF ontology.

In addition to providing simple directory services, you could use information from FOAF in many ways.

Or how about one that finds links to FOAF files on web pages your browsing and then blogs that information to your people blog?

This article has attempted to address some common issues, inspired in part by experience with the FOAF vocabulary.

The graph pattern's second triple matches the object of the contributor's foaf: weblog property.

Which describes currently documented FOAF properties.

There is much more to the FOAF vocabulary than I have space to explain here.

A SELECT query whose graph pattern included foaf: depiction would only find three solutions.

For instance, I could create an FOAF description for several other people.

In the bloggers. rdf model, contributor will match the foaf: Agent blank-node at the top of Figure 1.

Which aggregates and answers queries about FOAF information.

This would appear to present a difficulty for the FOAF vocabulary.

This plan has been shown to work well in the FOAF (Friend-of-a-friend) project for expressing personal information and social networks.

In my experiments I have assumed that certification carries the semantics of the signer endorsing the statements in the contained FOAF file.

What legal obligations do aggregators of FOAF information have under the data-protection law in the jurisdiction under which they operate?

Because code often speaks louder than words, Listing 1 shows a small FOAF description of myself.

I'm going to examine a new project, with certain similarities, called Friend-of-a-Friend (FOAF).

Spidering agents are notified that certain FOAF files aren't encrypted for them, and the agents can then ignore those files.

FOAF has the potential to become an important tool in managing communities.

The vCard RDF schema is more general in coverage than the FOAF schema, but we don't need its additional properties.

Listing 11's GRAPH clause matches on each person node in the named FOAF graphs given to the query.

Listing 5 shows a very small FOAF graph, expressed in Turtle syntax.

Listing 8 shows how you can use this instead of the mbox property in a FOAF file.

Listing 3 shows two methods from the FOAF class in bloginfo. py (see Resources for links to this code).

I concluded my most recent column by posing a series of questions raised by my use of the FOAF application.

Links and aggregates FOAF and RDF content.

The first line defines a prefix for the data, so that can be abbreviated as foaf: name.

The same principles apply to FOAF.

Contribute thoughts about the future development of FOAF at.

Let's start with the core problem that FOAF addresses: how to identify people in order to describe them.

For merging FOAF descriptions to continue to work, processing agents must instead merge on the

The particular mechanism used in FOAF is the RDF Schema

Restricting FOAF to a community of trust

Listing 7: Fragment showing linking of an encrypted FOAF file

XML Watch: Support online communities with FOAF