Knowledge Representation and Reasoning Tools

Overview

The KR library is for working with knowledge representations and knowledge bases. Currently it facilitates use of RDF-based representations backed by triple-/quad- stores. It provides a consistent clojure based way of interacting with its backing implementations, which currently include the Jena and Sesame APIs.

update: see the note on Sesame Versions

Basic Setup

The primary api functions you're likely to use come from the kr-core apis:

(use 'edu.ucdenver.ccp.kr.kb)
(use 'edu.ucdenver.ccp.kr.rdf)
(use 'edu.ucdenver.ccp.kr.sparql)

To actually get a KB instance to work with you'll need to make sure the implementation-specific code is loaded:

(require 'edu.ucdenver.ccp.kr.sesame.kb)
;; OR
(require 'edu.ucdenver.ccp.kr.jena.kb)

a kb instance can then be acquired with the kb function, for example:

(kb :sesame-mem)  ; an in-memory sesame kb

The kb function can take keyword arguments such as :sesame-mem or :jena-mem or it can take names of several native jena or sesame objects or pre-constructed jena or sesame instances to create a kb wrapper around (e.g., a jena Model or a sesame Sail).

kb's need some help knowing what the namespace mappings are, the server mappings can be brought down from a third party kb by calling (synch-ns-mappings my-kb) or you can add a few:

(register-namespaces my-kb
                     '(("ex" "http://www.example.org/") 
                       ("rdf" "http://www.w3.org/1999/02/22-rdf-syntax-ns#")
                       ("foaf" "http://xmlns.com/foaf/0.1/")))
;;the return value is the new modified kb - hang onto it

Basic Use

Once you have a KB you can load rdf triple or files:

  ;;in parts
  (add my-kb 'ex/KevinL 'rdf/type 'ex/Person)
  ;;as a triple
  (add my-kb '(ex/KevinL foaf/name "Kevin Livingston"))

Query for RDF triples:

(ask-rdf my-kb nil nil 'ex/Person)
;;true

(query-rdf my-kb nil nil 'ex/Person)
;;((ex/KevinL rdf/type ex/Person))

Query with triple patterns (SPARQL):

(query my-kb '((?/person rdf/type ex/Person)
               (?/person foaf/name ?/name)
               (:optional ((?/person foaf/mbox ?/email)))))
;;({?/name "Kevin Livingston", ?/person ex/KevinL})

More Details

The examples also provide details on how to interact with a KB, with run-able poms: https://github.com/drlivingston/kr/tree/master/kr-examples

These include examples of connecting to a remote repository and a local in-memory repository.

More detailed uses can be found in the test cases for both the KB, RDF, and SPARQL APIs. They are here: https://github.com/drlivingston/kr/tree/master/kr-core/src/test/clojure/edu/ucdenver/ccp/test/kr

Maven

releases are deployed to clojars:

<repository>
  <id>clojars.org</id>
  <url>http://clojars.org/repo</url>
</repository>

the core dependency is kr-core:

<dependency>
  <groupId>edu.ucdenver.ccp</groupId>
  <artifactId>kr-core</artifactId>
  <version>1.4.8</version>
</dependency>

but the core dependency is unnecessary if you are brining in either the sesame or jena implementations:

<dependency>
  <groupId>edu.ucdenver.ccp</groupId>
  <artifactId>kr-sesame-core</artifactId>
  <version>1.4.8</version>
</dependency>

<dependency>
  <groupId>edu.ucdenver.ccp</groupId>
  <artifactId>kr-jena-core</artifactId>
  <version>1.4.8</version>
</dependency>

Acknowledgements

open sourced by:
CCP Lab
University of Colorado Denver
primary developer: Kevin Livingston