Programatically infers triples using custom functions or methods. – Linked Data for Professional Education

RDFLib Examples Package

Tue, 03 May 2016 13:01:46 +0000

This documentation includes examples on the following subjects: 1) creating named graphs and working with the conjunction of all the graphs; 2) registering new mappings between literal datatypes and Python objects; 3) adding custom evaluation functions to handle certain SPARQL Algebra elements; 4) overloading Python operators on URIRefs to allow for creating path operators directly in Python; 5) binding variables,; 6) processing RDFa data from the Web. These examples all live in ./examples in the source-distribution of RDFLib.

URL: http://rdflib.readthedocs.org/en/stable/apidocs/examples.html
Keywords: Python, SPARQL, RDFa
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P30M
Educational use: instruction
Educational audience: student
Interactivity type: expositive

XQuery and JavaScript Semantics APIs

Abi Evans — Tue, 19 Apr 2016 01:24:26 +0000

This is the tenth chapter in MarkLogic's "Semantic Developer's Guide". It describes the XQuery and JavaScript Semantics APIs, which include an XQuery library module, built-in semantics functions, and support for SPARQL, SPARQL Update, and RDF. This chapter also includes examples using the Semantics API, which is an API designed to create, query, update, and delete triples and graphs in MarkLogic.

URL: https://docs.marklogic.com/guide/semantics/semantics-api
Keywords: Semantics API, JavaScript, XQuery, Triples
Publisher: MarkLogic
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P40M
Educational use: instruction
Educational audience: professional
Interactivity type: mixed

Inference

Sun, 17 Apr 2016 23:37:59 +0000

This is the seventh chapter in MarkLogic's "Semantic Developer's Guide". This chapter describes the process of discovering new facts about data based on a set of rules. Inference with semantic triples means that automatic procedures can generate new relationships (new facts) from existing triples. An inference query is any SPARQL query that is affected by automatic inference(i.e., automatic processing by a computer program). New facts may be added to the database (forward-chaining inference), or they may be inferred at query time (backward chaining inference), depending on the implementation. MarkLogic supports backward-chaining inference.

URL: https://docs.marklogic.com/guide/semantics/inferencing
Keywords: REST API, XQuery, Ruleset, JavaScript, SPARQL
Publisher: MarkLogic
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P30M
Educational use: instruction
Educational audience: professional
Interactivity type: expositive

MarkLogic: Next Steps

Tue, 19 Jan 2016 14:59:48 +0000

This is just one of several tutorials in a sequence, and they should be done in order to gain the most benefit. This final tutorial presents a few final challenges- using the data loaded and used in the previous exercises, try to answer a series of questions about Aldous Huxley.

URL: http://developer.marklogic.com/learn/semantics-exercises/next-steps
Keywords: XQuery, SPARQL, Graph traversal
Publisher: MarkLogic
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P15M

MarkLogic: Using the Triple Index

Tue, 19 Jan 2016 14:59:48 +0000

This brief exercise makes use of a triple index outside of SPARQL. It relies on previously loaded data and builds on queries which were run in previous exercises. Also contains advice regarding the use of SPARQL vs. XQuery. This is just one of several tutorials in a sequence, and they should be done in order to gain the most benefit.

URL: http://developer.marklogic.com/learn/semantics-exercises/triple-index
Keywords: XQuery, SPARQL
Publisher: MarkLogic
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P15M

Semantic Inferencing with MarkLogic

Sat, 16 Jan 2016 13:43:28 +0000

This tutorial familiarizes the user with concepts and steps for using Semantic Inferencing in MarkLogic. The concepts of inference, rulesets, asserted triples and ontology triples are described with examples. Forward and backward chaining is compared and contrasted. RDF Schema, OWL, and path-based inference are also described and demonstrated. Includes discussion of best practices for optimizing inference performance.

URL: http://mlu.marklogic.com/ondemand/f960d986
Keywords: SPARQL, XQuery, Rules Based Inference, JavaScript, REST API
Publisher: MarkLogic
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P20M
Interactivity type: expositive

ELITE: An Entailment-based Federated Query Engine for Complete and Transparent Semantic Data Integration

Abi Evans — Tue, 15 Sep 2015 02:33:08 +0000

In recent years, the core of the Semantic Web has evolved to a conceptual layer built by a set of ontologies mapped onto data distributed in numerous data sources which are interlinked, interpreted and processed in terms of semantics. In this context federated querying of Linked Data becomes a central issue. This paper presents the federated query engine ELITE, which facilitates a complete and transparent integration and querying of distributed autonomous data sources.

URL: http://www.semanco-project.eu/index_htm_files/ELITE.pdf
Keywords: Description Logics, Query rewriting, Web Ontology Language (OWL), Entailment Regimes, Ontology-based Data Access (OBDA)
Author: Nolle, Andreas
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P45M
Educational use: professionalDevelopment
Educational audience: professional

Semantic Python: Mastering Linked Data with Python

Abi Evans — Thu, 13 Aug 2015 13:45:22 +0000

Python offers a very powerful and easy to use library to work with Linked Data: rdflib. RDFLib is a lightweight and functionally complete RDF library, allowing applications to access, create and manage RDF graphs. This talk presents a general overview of the main features provided by the rdflib package. Several code examples are discussed, along with a case study concerning the analysis of a (semantic) social graph. Begins with a non-trivial overview of Linked Data Principles and the RDF Data Model, before moving on to the programming examples.

URL: https://www.youtube.com/watch?v=5DCS9LE-8rE
Keywords: SQ-Lite, RDFLib, Python, SPARQL, DBPedia
Author: Maggio, Valerio
Publisher: PyData
Date created: 2014-07-26 07:00:00.000
Language: http://id.loc.gov/vocabulary/iso639-2/eng
Time required: P50M
Educational use: professionalDevelopment