Kingsley Idehen's Blog Data Space

1. It isn't World Wide Web Specific (HTTP != World Wide Web)
2. It isn't Open Data Specific
3. It isn't about "Free" (Beer or Speech)
4. It isn't about Markup (so don't expect to grok it via "markup first" approach)
5. It's about Hyperdata - the use of HTTP and REST to deliver a powerful platform agnostic mechanism for Data Reference, Access, and Integration.

When trying to understand HTTP based Linked Data, especially if you're well versed in DBMS technology use (User, Power User, Architect, Analyst, DBA, or Programmer) think:

• Open Database Connectivity (ODBC) without operating system, data model, or wire-protocol specificity or lock-in potential
• Java Database Connectivity (JDBC) without programming language specificity
• ADO.NET without .NET runtime specificity and .NET bound language specificity
• OLE-DB without Windows operating system & programming language specificity
• XMLA without XML format specificity - with Tabular and Multidimensional results formats expressible in a variety of data representation formats.
• All of the above scoped to the Record rather than Container level, with Generic HTTP scheme URIs associated with each Record, Field, and Field value (optionally)

Remember the need for Data Access & Integration technology is the by product of the following realities:

1. Human curated data is ultimately dirty, because:
   • our thick thumbs, inattention, distractions, and general discomfort with typing, make typos prevalent
   • database engines exist for a variety of data models - Graph, Relational, Hierarchical;
   • within databases you have different record container/partition names e.g. Table Names;
   • within a database record container you have records that are really aspects of the same thing (different keys exist in a plethora of operational / line of business systems that expose aspects of the same entity e.g., customer data that spans Accounts, CRM, ERP application databases);
   • different field names (one database has "EMP" while another has "Employee") for the same record
   .
2. Units of measurement is driven by locale, the UK office wants to see sales in Pounds Sterling while the French office prefers French Francs
3. All of the above is subject to context halos which can be quite granular re. sensitivity e.g. staff travel between locations that alter locales and their roles; basically, profiles matters a lot.

Related

• ODBC and WODBC (Web Open Database Connectivity) Comparison
• Creating, Deploying, and Exploiting Linked Data Presentation
• Open Data Protocol Project

Here are 5 powerful benefits you can immediately derive from the combination of Virtuoso and Amazon's AWS services (specifically the EC2 and EBS components):

1. Acquire your own personal or service specific data space in the Cloud. Think DBase, Paradox, FoxPRO, Access of yore, but with the power of Oracle, Informix, Microsoft SQL Server etc.. using a Conceptual, as opposed to solely Logical, model based DBMS (i.e., a Hybrid DBMS Engine for: SQL, RDF, XML, and Full Text)
2. Ability to share and control access to your resources using innovations like FOAF+SSL, OpenID, and OAuth, all from one place
3. Construction of personal or organization based FOAF profiles in a matter of minutes; by simply creating a basic DBMS (or ODS application layer) account; and then using this profile to create strong links (references) to all your Data silos (esp. those from the Web 2.0 realm)
4. Load data sets from the LOD cloud or Sponge existing Web resources (i.e., on the fly data transformation to RDF model based Linked Data) and then use the combination to build powerful lookup services that enrich the value of URLs (think: Web addressable reports holding query results) that you publish
5. Bind all of the above to a domain that you own (e.g. a .Name domain) so that you have an attribution-friendly "authority" component for resource URLs and Entity URIs published from your Personal Linked Data Space on the Web (or private HTTP network).

In a nutshell, the AWS Cloud infrastructure simplifies the process of generating Federated presence on the Internet and/or World Wide Web. Remember, centralized networking models always end up creating data silos, in some context, ultimately! :-)

We have just released an Amazon EC2 based public Snapshot of DBpedia 3.4. Thus, you can now instantiate a personal and/or service specific variant of the DBpedia 3.4 Linked Data Space. Basically, you can replicate what we host, within minutes (as opposed to days). In addition, you no longer need to squabble --on an unpredictable basis with others-- for the infrastructure resources behind DBpedia's public instance, when using the SPARQL Endpoint, Faceted Search & Find Services, or HTML Browser Pages etc.

How Does It work?

1. Instantiate a Virtuoso EC2 AMI (paid variety, which is aggressively priced at $49.99 for setup and $19.99 per month thereafter)
2. Mount the shared DBpedia 3.4 public snapshot
3. Start Virtuoso Server
4. Start exploiting the DBpedia Linked Data Space.

What Interfaces are exposed?

1. SPARQL Endpoint
2. Linked Data Viewer Pages (as you see in the public DBpedia instance)
3. Faceted Search & Find UI and Web Services (REST or SOAP)
4. All the inference rules for UMBEL, SUMO, YAGO, OpenCYC, and DBpedia-OWL data dictionaries
5. Type Correlations Between DBpedia and Freebase

Enjoy!

Personally, I believe that we've actually reached a watershed moment re. the evolution of the Web from a mesh of Linked Data Containers (Web of Linked Documents) to a mesh of Linked Data Items (entities or real world objects).

The journey towards this watershed moment started with the Semantic Web Project, gained focus and pragmatism via the Linked Data meme, attained substance & credibility via efforts such as DBpedia and the resulting cloud of Open Linked Data Spaces, and finally arrived at the most important destination of all: broad comprehension and coherence, via RDFa.

Over the years, I've chronicled the journey above via entries in this particular data space (my blog) and most recently, via my rapid-fire comments and debates on Twitter (basically hastag #linkeddata account: kidehen).

On a parallel front re. my chronicles, I've periodically had conversations with Jon Udell, who has always provided a coherent sounding board and reconciliation framework for my world views and open data access vision; naturally, this has a lot to do with his holistic grasp of the big picture issues, associated technical details, and special communication prowess :-)

Against this backdrop, I refer you to my most recent podcast conversation with Jon, which is about how the tandem of HTML+RDFa and the GoodRelations vocabulary deliver the critical missing links re. broad comprehension of the Semantic Web vision en route to mass exploitation.

Related

• Mark Birbeck Introduces RDFa
• RDFa Handbook
• GoodRelations Usage Examples & Templates
• Be the master of your own search index

Situation Analysis

As the "Linked Data" meme has gained momentum you've more than likely been on the receiving end of dialog with Linked Open Data community members (myself included) that goes something like this:

"Do you have a URI", "Get yourself a URI", "Give me a de-referencable URI" etc..

And each time, you respond with a URL -- which to the best of your Web knowledge is a bona fide URI. But to your utter confusion you are told: Nah! You gave me a Document URI instead of the URI of a real-world thing or object etc..

What's up with that?

Well our everyday use of the Web is an unfortunate conflation of two distinct things, which have Identity: Real World Objects (RWOs) & Address/Location of Documents (Information bearing Resources).

The "Linked Data" meme is about enhancing the Web by unobtrusively reintroducing its core essence: the generic HTTP URI, a vital piece of Web Architecture DNA. Basically, its about so realizing the full capabilities of the Web as a platform for Open Data Identification, Definition, Access, Storage, Representation, Presentation, and Integration.

What is a Real World Object?

People, Places, Music, Books, Cars, Ideas, Emotions etc..

What is a URI?

A Uniform Resource Identifier. A global identifier mechanism for network addressable data items. Its sole function is Name oriented Identification.

URI Generic Syntax

The constituent parts of a URI (from URI Generic Syntax RFC) are depicted below:

What is a URL?

A location oriented HTTP scheme based URI. The HTTP scheme introduces a powerful and inherent duality that delivers:

1. Resource Address/Location Identifier
2. Data Access mechanism for an Information bearing Resource (Document, File etc..)

So far so good!

What is an HTTP based URI?

The kind of URI Linked Data aficionados mean when they use the term: URI.

An HTTP URI is an HTTP scheme based URI. Unlike a URL, this kind of HTTP scheme URI is devoid of any Web Location orientation or specificity. Thus, Its inherent duality provides a more powerful level of abstraction. Hence, you can use this form of URI to assign Names/Identifiers to Real World Objects (RWO). Even better, courtesy of the Identity/Address duality of the HTTP scheme, a single URI can deliver the following:

1. RWO Identfier/Name
2. RWO Metadata document Locator (courtesy of URL aspect)
3. Negotiable Representation of the Located Document (courtesy of HTTP's content negotiation feature).

What is Metadata?

Data about Data. Put differently, data that describes other data in a structured manner.

How Do we Model Metadata?

The predominant model for metadata is the Entity-Attribute-Value + Classes & Relationships model (EAV/CR). A model that's been with us since the inception of modern computing (long before the Web).

What about RDF?

The Resource Description Framework (RDF) is a framework for describing Web addressable resources. In a nutshell, its a framework for adding Metadata bearing Information Resources to the current Web. Its comprised of:

1. Entity-Attribute-Value (aka. Subject-Predictate-Object) plus Classes & Relationships (Data Dictionaries e.g., OWL) metadata model
2. A plethora of instance data representation formats that include: RDFa (when doing so within (X)HTML docs), Turtle, N3, TriX, RDF/XML etc.

What's the Problem Today?

The ubiquitous use of the Web is primarily focused on a Linked Mesh of Information bearing Documents. URLs rather than generic HTTP URIs are the prime mechanism for Web tapestry; basically, we use URLs to conduct Information -- which is inherently subjective -- instead of using HTTP URIs to conduct "Raw Data" -- which is inherently objective.

Note: Information is "data in context", it isn't the same thing as "Raw Data". Thus, if we can link to Information via the Web, why shouldn't we be able to do the same for "Raw Data"?

How Does the Link Data meme solve the problem?

The meme simply provides a set of guidelines (best practices) for producing Web architecture friendly metadata. Meaning: when producing EAV/CR model based metadata, endow Subjects, their Attributes, and Attribute Values (optionally) with HTTP URIs. By doing so, a new level of Link Abstraction on the Web is possible i.e., "Data Item to Data Item" level links (aka hyperdata links). Even better, when you de-reference a RWO hyperdata link you end up with a negotiated representations of its metadata.

Conclusion

Linked Data is ultimately about an HTTP URI for each item in the Data Organization Hierarchy :-)

Related

1. History of how "Resource" became part of URI - historic account by TimBL
2. Linked Data Design Issues Document - TimBL's initial Linked Data Guide
3. Linked Data Rules Simplified - My attempt at simplifying the Linked Data Meme without SPARQL & RDF distraction
4. Linked Data & Identity - another related post
5. The Linked Data Meme's Value Proposition
6. My Del.icio.us hosted Bookmark Data Space for Identity Schemes
7. TimBL's Ted Talk re. "Raw Linked Data".

As espoused by the Ubuntu philosophy, no Human is an Island. Thus, although the objects of our sociality are vast and varied; that said, the basic foundation still centers on the pursuit and/or delivery of products and services.

Today, the we put stuff on the Web because we want it do be discovered as part of a "sharing act". Likewise, we make regular use of Search Engine Services because we want to "Find" stuff in a productive manner.

Putting, the above in context, you don't need to be Einstein to figure out that to date the Web hasn't enabled vendors to describe their products and services clearly. Likewise, it hasn't enabled us to describe what we want, when we want it, and how much we are willing to pay etc. Basically, the SDQ of Web Content is excruciatingly low!

The Linked Data meme is about using the essence of the Web -- HTTP URIs -- as the mechanism for conducting data across the Web that unambiguously unveils basic things like:

1. Using a personal profile to describe exactly who I am, my interests, favorite things, what I want (wishlist), what I have to offer (offerlist) etc.
2. Using an company profile to describe my entire product catalog, inventory levels, store locations, distributor and reseller networks, feature specs, price specs, deal terms and duration, and even opening and closing hours.

Conclusions

A Web of Linked Data enables a complete redefinition of eCommerce, and that's just for starters :-)

Related

• Post Introducing SDQ
• Serendipitous Discovery Quotient (SDQ): The Future of SEO? Or an Abstract Concept?

What is Linked Data?

The primary topic of a meme penned by TimBL in the form of a Design Issues Doc (note: this is how TimBL has shared his thoughts since the Beginning of the Web).

There are a number of dimensions to the meme, but its primary purpose is the reintroduction of the HTTP URI -- a vital component of the Web's core architecture.

What's Special about HTTP URIs?

They possess an intrinsic duality that combines persistent and unambiguous Data Identity with platform & representation format independent Data Access. Thus, you can use a string of characters that look like a contemporary Web URL to unambiguously achieve the following:

1. Identity or Name Anything of Interest
2. Describe Anything of Interest by associating the Description Subject's Identity with a constellation of Attribute and Value pairs (technically: an Entity-Attribute-Value or Subject-Predicate-Object graph)
3. Make the Description of Named Things of Interest discoverable on the Web by implicitly binding the aforementioned to Documents that hold their descriptions (technically: metadata documents or information resources)

What's the basic value proposition of the Linked Data meme?

Enabling more productive use of the Web by users and developers alike. All of which is achieved by tweaking the Web's Hyperlinking feature such that it now includes Hypertext and Hyperdata as link types.

Note: Hyperdata Linking is simply what an HTTP URI facilitates.

Examples problems solved by injecting Linked Data into the Web:

1. Federated Identity by enabling Individuals to unambiguously Identify themselves (Profiles++) courtesy of existing Internet and Web protocols (e.g., FOAF+SSL's WebIDs which combine Personal Identity with X.509 certificates and HTTPs based client side certification)
2. Security and Privacy challenge alleviation by delivering a mechanism for policy based data access that feeds off federated individual identity and social network (graph) traversal
3. Spam Busting via the above
.
4. Increasing the Serendipitous Discovery Quotient (SDQ) of Web accessible resources by embedding Rich Metadata into (X)HTML Documents e.g., structured descriptions of your "WishLists" and "OfferLists" via a common set of terms offered by vocabularies such as GoodRelations and SIOC
5. Coherent integration of disparate data across the Web and/or within the Enterprise via "Data Meshing" rather than "Data Mashing"
6. Moving beyond imprecise statistically driven "Keyword Search" (e.g. Page Rank) to "Precision Find" driven by typed link based Entity Rank plus Entity Type and Entity Property filters.

Conclusion

If all of the above still falls into the technical mumbo-jumbo realm, then simply consider Linked Data as delivering Open Data Access in granular form to Web accessible data -- that goes beyond data containers (documents or files).

The value proposition of Linked Data is inextricably linked to the value proposition of the World Wide Web. This is true, because the Linked Data meme is ultimately about an enhancement of the current Web; achieved by reintroducing its architectural essence -- in new context -- via a new level of link abstraction, courtesy of the Identity and Access duality of HTTP URIs.

As a result of Linked Data, you can now have Links on the Web for a Person, Document, Music, Consumer Electronics, Products & Services, Business Opening & Closing Hours, Personal "WishLists" and "OfferList", an Idea, etc.. in addition to links for Properties (Attributes & Values) of the aforementioned. Ultimately, all of these links will be indexed in a myriad of ways providing the substrate for the next major period of Internet & Web driven innovation, within our larger human-ingenuity driven innovation continuum.

Related

• Recipes for Describing Your Business and its Offerings using the GoodRelations Vocabulary / Schema
• Solving Real Problems with RDF based Linked Data
• Other Linked Data Posts from this Blog oriented Linked Data Space (goes back a few years!)
• Various practical Linked Data demo links from my Del.icio.us Bookmark oriented Data Space
• My personal WebID which is conduit to a Linked Data mesh covering vast variety of things I've opted to share with others via the Web (best viewed using a Linked Data aware User Agent like ODE).

Based on the prevalence of confusion re. the Linked Data meme, here are a few important points to remember about the World Wide Web.

1. Its an HTTP based Network Cluster within the Internet (remember: Networks are about meshes of Nodes connected by Links)
2. Its underlying data model is that of a Network (we've had Network Data models for eons. EAV/CR is an example)
3. Links are facilitated via URIs
4. Until recently the granularity of Networking on the Web was scoped to Data Containers (documents) (due to prevalence of URL style links
5. The Linked Data meme adds Data Item (Datum) level granularity to World Wide Web networking via HTTP URIs
6. Data Items become Web Reference-able when you Identify/Name them using HTTP based URIs
7. An HTTP URI implicitly binds a Web Reference-able Data Item (Entity, Datum, Data Object, Resource) to its Web Accessible Metadata
8. Web Accessible Metadata resides within Data Containers (documents or information resources)
9. The representation of a Web Accessible Metadata container is negotiable
10. I am able to write and dispatch this blog post courtesy of the Web features listed above
11. You are able to explore the many dimensions to data exposed by this blog should you decide to explore the Linked Data mesh exposed by this post's HTTP URI (via its permalink permalink)

The HTTP URI is the secret sauce of the Web that is powerfully and unobtrusively reintroduced via the Linked Data meme (classic back to the future act). This powerful sauce possess a unique power courtesy of its inherent duality i.e., how it uniquely combines Data Item Identity (think keys in traditional DBMS parlance) with Data Access (e.g. access to negotiable representations of associated metadata).

As you can see, I've made no mention of RDF or SPARQL, and I can still articulate the inherent value of the "Linked Data" dimension that the "Linked Data" meme adds to the World Wide Web.

As per usual this post is a live demonstration of Linked Data (dog-food style) :-)

Related

• Greg Boutin's post about Linked Data Brand Management
• Ian Davis' "Linked Data Brand" post
• Paul Miller's "Does Linked Data need RDF" post

As a compliment to the most recent Linked Data Design Issues note by TimBL, I would like to add this subtle tweak to the enumerated rules:

1. Identify or Name things using HTTP URIs
2. Describe things using the RDF metadata model
3. Increase link data mesh density on the Web by linking (referring) to things in other data spaces using their HTTP URIs.

If you perform the steps above, on any HTTP network (e.g. World Wide Web), you implicitly bind the Names/Identifiers of things to negotiable representations of their metadata (description) bearing documents.

Also note, you can create and deploy the resulting RDF metadata using any of the following approaches:

1. RDFa within (X)HTML documents
2. N3, Turtle, TriX, RDF/XML etc. based documents
3. Programmatically generated variants of 1&2.

Related

• What is the Linked Data meme about?
• Simple Explanation of RDF and Linked Data Dynamics

Situation Analysis:

Dr. Dre is one of the artists in the Linked Data Space we host for the BBC. He is also referenced in music oriented data spaces such as DBpedia, MusicBrainz and Last.FM (to name a few).

Challenge:

How do I obtain a holistic view of the entity "Dr. Dre" across the BBC, MusicBrainz, and Last.FM data spaces? We know the BBC published Linked Data, but what about Last.FM and MusicBrainz? Both of these data spaces only expose XML or JSON data via REST APIs?

Solution:

Steps:

1. Go to Last.FM and search using pattern: Dr. Dre (you will end up with this URL: http://www.last.fm/music/Dr.+Dre)
2. Go to the Virtuoso powered BBC Linked Data Space home page and enter: http://bbc.openlinksw.com/about/html/http://www.last.fm/music/Dr.+Dre
3. Go to the BBC Linked Data Space home page and type full text pattern (using default tab): Dr. Dre, then view Dr. Dre's metadata via the Statistics Link.

What Happened?

The following took place:

1. Virtuoso Sponger sent an HTTP GET to Last.FM
2. Distilled the "Artist" entity "Dr. Dre" from the page, and made a Linked Data graph
3. Inverse Functional Property and sameAs reasoning handled the Meshup (augmented graph from a conjunctive query processing pipeline)
4. Links for "Dr. Dre" across BBC (sameAs), Last.FM (seeAlso), via DBpedia URI.

The new enhanced URI for Dr. Dre now provides a rich holistic view of the aforementioned "Artist" entity. This URI is usable anywhere on the Web for Linked Data Conduction :-)

Related (as in NearBy)

• Augmenting Last.fm Data with BBC data on the Talis Platform