Juan Sequeda

The Business Value of Reasoning with Ontologies

[Editor’s note: this guest post was co-written by Héctor Pérez-Urbina (Clark & Parsia) and Juan Sequeda (Capsenta)] Important enterprise business logic is often buried deep within a complex ecosystem of applications. Domain constraints and assumptions, as well as the main actors and the relations with one another, exist only implicitly in thousands of lines of…

Introduction to: Reasoners

Reasoning 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…

Introduction to: OWL Profiles

OWL, the Web Ontology Language has been standardized by W3C as a powerful language to represent knowledge (i.e. ontologies) on the Web. OWL has two functionalities. The first functionality is to express knowledge in an unambiguous way. This is accomplished by representing knowledge as set of concepts within a particular domain and the relationship between these concepts. If…

Introduction to: Triplestores

Triplestores are Database Management Systems (DBMS) for data modeled using RDF. Unlike Relational Database Management Systems (RDBMS), which store data in relations (or tables) and are queried using SQL, triplestores store RDF triples and are queried using SPARQL. A key feature of many triplestores is the ability to do inference. It is important to note…

Summary of 11th International Semantic Web Conference

Last week, the 11th International Semantic Web Conference (ISWC 2012) took place in Boston. It was an exciting week to learn about the advances of the Semantic Web and current applications. The first two days, Sunday November 11 and Monday November 12, consisted of 18 workshops and 8 tutorials. The following three days (Tuesday November…

Introduction to: SKOS

SKOS, which stands for Simple Knowledge Organization System, is a W3C standard, based on other Semantic Web standards (RDF and OWL), that provides a way to represent controlled vocabularies, taxonomies and thesauri. Specifically, SKOS itself is an OWL ontology and it can be written out in any RDF syntax. Before we dive into SKOS, what is…

R2RML and Direct Mapping: W3C Proposed Recommendations

Yesterday, the W3C announced the advancement to Proposed Recommendations of two Relational Database to RDF (RDB2RDF) documents: 1) R2RML: RDB to RDF Mapping Language and 2) A Direct Mapping of Relational Data to RDF. Additionally, two Working Group Notes were also published: R2RML and Direct Mapping Test Cases and RDB2RDF Implementation Report. Given that a vast amount…

Introduction to: RDF vs XML

There has always been a misconception between the relationship of RDF and XML. The main difference: XML is a syntax while RDF is a data model. RDF has several syntaxes (Turtle, N3, etc) and XML is one of those (known as RDF/XML). Actually, RDF/XML is the only W3C standard syntax for RDF (Currently, there is Last Call…

Twitter, the new kid on the Semantic Web block

Remember how search engines can show nice snippets in their search results thanks to the structured data that webmasters embedded in the HTML of their webpages (RDFa, schema.org, etc)? Additionally, Facebook gains insight about user’s interest through structured data on webpages (i.e. Open Graph Protocol). Now there is a new kid on the block: Twitter.…