Message Mediation in the Semantic Web

nulllogicone.net is an abstract system for mediating messages between unknown parties, describing authors, messages, and recipients. It consists of a Cycle Model [SAPCT], the Word Space [NKBZ], and a Mediation Logic [OgIf]. A web application against a central database server is realized as a reference implementation.

Instances

All entities are data records that can be displayed as html pages, RDF documents, or JSON documents. The RDF documents are generated on the fly from the database records and can be retrieved by appending .rdf to the URL. For JSON format, append .json.

In the database tables, the key fields are GUIDs. These are used in URIrefs and URLs. A URIref in an RDF statement consists of the base namespace (https://nulllogicone.net/) followed by the full class name from [SAPCT][NKBZ] with appended GUID. These can display further information on a webpage as URLs.

SPARQL

For querying the data using semantic web standards, a SPARQL endpoint is available at /sparql. SPARQL (SPARQL Protocol and RDF Query Language) enables powerful queries across the entire knowledge graph using W3C standards. The endpoint is built on Ontop, which provides a virtual knowledge graph layer over the relational database, automatically translating SPARQL queries to SQL.

For interactive query development, a visual query interface with syntax highlighting, autocomplete, and result visualization is powered by YASGUI, providing an intuitive environment for exploring and testing SPARQL queries.)
Click to open: /sparql/ui (in new tab)

Open interactive query examples with syntax highlighting and one-click copy functionality to get started quickly.

Example SPARQL query to retrieve Stamm entities:

PREFIX nlo: <http://nulllogicone.net/schema.rdfs#>
SELECT ?stamm ?name ?email
WHERE {
  ?stamm a nlo:Stamm ;
         nlo:name ?name ;
         nlo:email ?email .
}
LIMIT 10

Visit /sparql for programmatic access and usage instructions, or use the SPARQL UI for interactive queries.

Examples

Schema

For the exchange of data at nulllogicone.net in RDF format, you can download the schema.rdfs file.
On the FRODO RDFSViz Tool page, the relationships can be visualized. As URL for the schema, you must specify the full path https://nulllogicone.net/schema.rdfs.

For storage in local databases or XML files, XSD documents are available as schema definitions for the entities with their fields and the definition of the table structure with their relational relationships. If they are used against web services, the types are bindingly defined in the wsdl files.

For setting up a relational table structure, there are SQL scripts which can be tailored to any use case.

Documents

nulllogicone.net mediates messages between unknown parties. For the exchange of data, the RDF format is used to enable decentralization and distributability.

RDF is based on XML and describes arbitrary resources with simple sentences consisting of subject, predicate, and object.

Example: A shortened RDF document

<?xml version="1.0" encoding= "utf-8"?> 
    <rdf:RDF
    xmlns:rdf=http://www.w3.org/1999/02/22-rdf-syntax-ns#
    xmlns:nlo="https://nulllogicone.net/schema.rdfs#" 
    xml:base="https://nulllogicone.net/">
    <nlo:Stamm rdf:about="https://nulllogicone.net/Stamm/?b4111e0e-48d9-42c4-a6f6-ec4991264947">
    <nlo:name>Oli</nlo:name>
    </nlo:Stamm>
    </rdf:RDF>

Web Applications

The web application www.oli-it.com is a question-answer game. It offers full functionality and the possibility to edit content.
With the MetaWeb Project www.metaweb-project.net, websites, blog posts, or images can be described and found.
UniSonus is a specialized application for collaboration and exchange among distance learning students.