How-to

W3C Publishes Linked Data Platform Best Practices and Guidelines

Photo of Arnaud Le Hors presenting the LDP at SemTechBiz 2014The W3C’s Linked Data Platform (LDP) Working Group has published a document outlining best practices and guidelines for implementing Linked Data Platform servers and clients. The document was edited by Cody Burleson, Base22, and Miguel Esteban Gutiérrez and Nandana Mihindukulasooriya of the Ontology Engineering Group, Universidad Politécnica de Madrid.

For those new to LDP, SemanticWeb.com has recently published the following materials:

WEBINAR: “Getting Started with the Linked Data Platform (LDP)” with LDP Working Group Chair, Arnaud Le Hors, IBM (pictured above presenting LDP work at the SemTechBiz conference last week).

ARTICLE: “Introduction to: Linked Data Platform” by Cody Burleson, Base 22

Those ready to dive into the nuts and bolts of the document will find detailed guidance on topics such as:

  • Predicate URIs
  • Use of relative URIs
  • Hierarchy and container URIs
  • Working with fragments
  • Working with standard datatypes
  • Representing relationships between resources
  • Finding established vocabularies

…and much more. See the full document at http://www.w3.org/TR/ldp-bp/

SemanticWeb.com congratulates the Working Group on this step and looks forward to reporting on use cases and implementations of LDP.

New Open Source Graph Database Cayley Unveiled (Video – Part 2)

Cayley Logo[Editor's note: This is Part 2 of a 3 part series. See Part 1 and Part 3]

Barak Michener, Software Engineer, Knowledge NYC has posted on the Google Open Source Blog about “Cayley, an open source graph database.”: “Four years ago this July, Google acquired Metaweb, bringing Freebase and linked open data to Google. It’s been astounding to watch the growth of the Knowledge Graph and how it has improved Google search to delight users every day. When I moved to New York last year, I saw just how far the concepts of Freebase and its data had spread through Google’s worldwide offices. I began to wonder how the concepts would advance if developers everywhere could work with similar tools. However, there wasn’t a graph available that was fast, free, and easy to get started working with. With the Freebase data already public and universally accessible, it was time to make it useful, and that meant writing some code as a side project.”

The post continues: “Cayley is a spiritual successor to graphd; it shares a similar query strategy for speed. While not an exact replica of its predecessor, it brings its own features to the table:RESTful API, multiple (modular) backend stores such as LevelDB and MongoDB, multiple (modular) query languages, easy to get started, simple to build on top of as a library, and of course open source. Cayley is written in Go, which was a natural choice. As a backend service that depends upon speed and concurrent access, Go seemed like a good fit.”

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New schema.org Technical Brief Available from LRMI and Cetis

Image of Technical Brief by LRMI about schema.org.The Learning Resource Metadata Initiative (LRMI) has released a technical briefing about schema.org. The paper was co-authored by Phil Barker and Lorna M. Campbell of Cetis, the Centre for Educational Technology, Interoperability and Standards.

LRMI, which we have reported on here, “has developed a common metadata framework for describing or ‘tagging’ learning resources on the web.”

The Cetis website says, “This briefing describes schema.org for a technical audience. It is aimed at people who may want to implement schema.org markup in websites or other tools they build but who wish to know more about the technical approach behind schema.org and how to implement it. We also hope that this briefing will be useful to those who are evaluating whether to implement schema.org to meet the requirements of their own organization.”

In making the announcement in a W3C list, Barker explained, “We often find that when explaining the technology approach of LRMI we are mostly talking about schema.org, so this briefing, which describes the schema.org specification for a technical audience should be of interest to anyone thinking about implementing or using LRMI in a website or other tool. It should also be of interest to people who plan to use schema.org for describing other types of resources.”

The technical brief can be downloaded from:

http://publications.cetis.ac.uk/2014/960

Introduction to: Reasoners

Name Tag: Hello, we are ReasonersReasoning is the task of deriving implicit facts from a set of given explicit facts. These facts can be expressed in OWL 2 ontologies and stored RDF triplestores. For example, the following fact: “a Student is a Person,” can be expressed in an ontology, while the fact: “Bob is a Student,” can be stored in a triplestore. A reasoner is a software application that is able to reason. For example, a reasoner is able to infer the following implicit fact: “Bob is a Person.”

Reasoning Tasks

Reasoning tasks considered in OWL 2 are: ontology consistency, class satisfiability, classification, instance checking, and conjunctive query answering.

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New “Linked Data” Book Launches – 50% Discount for Our Readers

Cover of Linked Data book by David Wood et alThis week, Manning Publications is launching the book “Linked Data,” by David Wood, Marsha Zaidman, Luke Ruth, and Michael Hausenblas.

As part of that launch, Manning is offering a one-day 50% discount for readers of SemanticWeb.com. The discount applies to all versions of “Linked Data”: eBook, print books, and Manning’s “MEAP” books (more on MEAP below). To claim the discount, use coupon code “12linksw” when ordering.

This offer expires at 11:59 pm (US EST) on December 6, so if you’re interested, act fast!

About the Book (description by David Wood):

The flexible, unstructured nature of the Web is being extended to act as a global database of structured data. Linked Data is a standards-driven model for representing structured data on the Web that gives developers, publishers, and information architects a consistent, predictable way to publish, merge and consume data. The Linked Data model offers the potential to standardize Web data in the same way that SQL standardized large-scale commercial databases. Linked Data has been adopted by many well-known institutions, including Google, Facebook, IBM, Oracle and government agencies, as well as popular Open Source projects such as Drupal.

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Web Developers Can Now Easily “Play” with RDFa

Kids playingYesterday, we announced RDFa.info, a new site devoted to helping developers add RDFa (Resource Description Framework-in-attributes) to HTML.

Building on that work, the team behind RDFa.info is announcing today the release of “PLAY,” a live RDFa editor and visualization tool. This release marks a significant step in providing tools for web developers that are easy to use, even for those unaccustomed to working with RDFa.

“Play” is an effort that serves several purposes. It is an authoring environment and markup debugger for RDFa that also serves as a teaching and education tool for Web Developers. As Alex Milowski, one of the core RDFa.info team, said, “It can be used for purposes of experimentation, documentation (e.g. crafting an example that produces certain triples), and testing. If you want to know what markup will produce what kind of properties (triples), this tool is going to be great for understanding how you should be structuring your own data.”

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Drs. Wood & Seuss Explain RDF in Two Minutes

“How would you explain RDF to my grandmother?  I still don’t get it…” a student recently asked of David Wood, CTO of 3Roundstones. Wood was speaking to a class called “Linked Data Ventures” and was made up of students from the MIT Computer Science Department and the Sloan School of Business. He responded by creating a slide deck and subsequent video explaining the Resource Description Framework using the classic Dr. Seuss style of rhyming couplets and the characters Thing 1 and Thing 2.

I hope this student’s grandmother found this as enjoyable as I did. (Video after the jump). Read more

Introduction to: RDFa 1.1 Lite

[Editor's Note: In our most recent SemanticLink podcast with special guest R.V. Guha, we mentioned RDFa 1.1 Lite, proposed by Ben Adida at last month's Schema.org workshop. Thanks to Manu Sporny for sharing the following look at RDFa 1.1 Lite.]

Summary: RDFa 1.1 Lite is a simple subset of RDFa consisting of the following attributes: vocab, typeof, property, rel, about and prefix.

During the schema.org workshop, a proposal was put forth by RDFa’s resident hero, Ben Adida, for a stripped down version of RDFa 1.1, called RDFa 1.1 Lite. The RDFa syntax is often criticized as having too much functionality, leaving first-time authors confused about the more advanced features. This lighter version of RDFa will help authors easily jump into the Linked Data world. The goal was to create a very minimal subset that will work for 80% of the folks out there doing simple markup for things like search engines. Read more

Upcoming Webcast: “Introduction to SKOS” with Bob DuCharme

Date: Thursday, October 6, 2011
Register Now
Time: 2:00pm ET / 11:00am PT
Cost: FREE

In August, we had the pleasure of hosting the excellent instructor, Bob DuCharme, as he walked us through an introduction to SPARQL: “SPARQL Queries, SPARQL Technology.” Next week, Bob will join us again, this time to introduce us to SKOS, the Simple Knowledge Organization System standard.

Description:

You manage a taxonomy, thesaurus, or some other kind of controlled vocabulary using a proprietary tool or perhaps even by emailing around spreadsheets to each other. Read more

Exploit That R&D!

 

Photo courtesy: Flickr/Bruce Berrien

So many semantic web efforts have their beginnings as R&D projects. Moving these projects from the lab into the real world has its challenges. But they can be overcome, and Daniel Field, business consultant at IT services and consulting company Atos Origin, has advice on how to manage them so the investment pays off.

In many cases these projects begin with multiple partners from different backgrounds –universities, businesses (including sometime competitors), and research centers on commission for other parties. “So they’re starting from a diverse set of perspectives,” he says. And the focus on meeting a mission’s specific goals can take center stage without due consideration of next steps – how, that is, to ensure that the partners contributing to the effort actually are able to exploit its achievements.

One thing Field recommends in order to realize that value is that the business case for the project be made at the proposal stage, and stuck to throughout the term of the effort. Critical to this is dealing upfront with questions around licensing and intellectual property.

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