SKOS-Utils

Introduction

We introduce the tool suite SKOS-Utils for the development and quality assessment of SKOS vocabularies (Simple Knowledge Organisation System). SKOS is a wide-spread standard for organizing hierarchical knowledge structures, that uses RDF as basic data model. SKOS-Utils provides converters for spreadsheets and mindmaps in order to facilitate the bottom-up development of SKOS vocabularies. SKOS-Utils also offers a suite of quality checks for testing the created vocabularies.

Project Structure

The main files of this project are located in the SKOSUtils directory. Here you can find the SKOSConverter, which includes functions to convert different data formats. You can simply switch between the well-known RDF syntax definitions XML, Turtle, and JSON-LD. The suite provides scripts to bridge this data model from/to the mind-mapping application XMind, to Graphviz, and from/to the spreadsheet application MS-Excel.

You can also find the SKOSQualityChecker in the directory of the same name. For the quality assessment a suite of configurable checks is executed as a pipeline. The results for each check are collected and reported after finishing the entire pipeline. Please note, that there is no real reasoning support for the checks, so the quality checks basically only analyse the knowledge graph as given from the file. We, however, can activate PoorMansReasoning in order to infer further triples to the graph that can be derived by very simple subclass and subproperty axioms.

The class QuickRDFConverter is used to quickly convert between different RDF syntaxes, such as XML, Turtle, and JSON-LD.

In the configs directory you can write your own configs to personalize the modules of this project.

How to Start

Before you start, make sure to install all required python packages (see requirements.txt). After this set the working directory to the root directory of this project. If you want to test, if everything is set up correctly, you can run ConverterExample and CheckerExample in the example directory.

Converter

To use the converter, simple specify the converter and input and output file and run the main-function of the SKOSConverter. For example: excel-to-rdf --input "D:/SKOSUTILS/Tests/TestData.xlsx" --output "D:/SKOSUTILS/Tests/TestData.ttl"

You can also use a YAML-config-file to set your settings permanently.

SKOS Quality Checker

To use the SKOS Quality Checker, you need to specify the path to the graph you want to check. Another parameter is the config-file you maybe want to use. For example: -config "configs\SKOSQualityChecker_config2.yaml" -graph "tests/Testdata/Bike_Testdata.ttl"

In this YAML-config-file you can set your settings permanently and choose advanced options for result outputs and set up the checker modules for your checker pipeline.

Advanced Settings

The settings in the charts below can be changed in the respective config file.

Converter

Setting name	Description
input_directory	Directory of your input file
output_directory	Directory where the output file will be created
file_name_prefix	You can set a name prefix if you use the same name for all file formats
name_space	Name space in your knowledge graph
name_space_key	The key of your name space
scheme_name	Name of your scheme
preferred_language	The preferred language of your knowledge graph
xMind_root_title	Set the root node title of your xMind graph

SKOS Quality Checker

Setting name	Description
input	Directory of your input file
output	Directory of your output file
add_datetime_to_output_file	Writes the current time and date at the end of your output file
write_results_to_excel	Creates an excel file if True, otherwise results are only shown on the console output
logging	Creates a log file if True
log_file	Specify the location and name of the used log file
tests	Create a test pipeline by writing all tests you want the SKOS Quality Checker to use

How to extend SKOS-Utils

If you want to extend the quality checks of SKOS-graphs, you can write new checker modules in rdf or SPARQL. Create the checker file and add your check to your YAML-config-file. Inherit from the class StructureTestInterfaceNavigate or StructureTestInterfaceSPARQL and set the status flag and the result message. Finally, implement the method find_concepts or the query to filter all wanted concepts from the given SKOS-graph. If you are using StructureTestInterfaceNavigate, your find_concepts method should return a set of concepts.