Hi Maxime, Don't know whether it would be best as part of jena core or in an extension, but sounds very interesting! Will let others comment on this. At work, one item in my backlog is to replace jscience by jsr363 - Units of Measurement | | | | | |
| | | | | Units of Measurement Units of Measurement provides a set of APIs and services for handling units and quantities. | | | | We use it for weather forecast and GIS, with things like wind speed, rain amount, etc. I think another GIS library that we use did the switch as well (some OGC lib I think). Perhaps it would be nice to consider taking a look at their api for compatibility with other systems. CheersBruno Sent from Yahoo Mail on Android On Tue, 27 Mar 2018 at 2:07, Maxime Lefrançois<maxime.lefranc...@emse.fr> wrote: Dear all, I am Associate Professor at MINES Saint-Étienne, France, working on Semantic Web and Linked Data. I'd like to let you know about our project *Custom Datatypes for Quantity Values*[1], that leverages the Unified Code of Units of Measures, a code system intended to include all units of measures being contemporarily used in international science, engineering, and business. Using our UCUM Datatypes, one can encode and query quantity values in a lightweight manner: PREFIX cdt: <http://w3id.org/lindt/custom_datatypes#> PREFIX ex: <http://example.org/> SELECT ?value1 ?value2 ?result WHERE{ VALUES ( ?value1 ?value2 ) { ( "1.0 m/s"^^cdt:speed "2 s"^^cdt:time ) } BIND( ?value1 * ?value2 AS ?result ) } Results in ---------------------------------------------------------------------- | value1 | value2 | result | ====================================================================== | "1.0 m/s"^^cdt:speed | "2 s"^^cdt:time | "2.0 m"^^cdt:length | See our demonstration online [2]. It uses *a fork of Jena where we implemented UCUM datatypes* [3] (in jena-core and jena-arq, with several unit tests) our implementation uses the recent JSR 385, Units of Measurement API 2.0, and the UCUM extension [4]. This is not the first project I develop into/using Jena. - I forked it to Supporting Arbitrary Custom Datatypes in RDF and SPARQL fetching some Javascript definition at the URI of the datatype [5] - I develop SPARQL-Generate, an extension of SPARQL implemented on ARQ to generate RDF from web documents in XML, JSON, CSV, HTML, CBOR, and plain text with regular expressions [6] If you agree we me that supporting UCUM datatypes would be a nice addition to Apache Jena and a nice contribution to the Semantic Web community, I would be willing to help to integrate our contribution to other modules (with jena-tdb, ... ), and help maintaining it in the future. Best regards, Maxime Lefrançois, Associate Professor, MINES Saint-Étienne [1] - http://w3id.org/lindt/custom_datatypes# [2] - http://w3id.org/lindt/playground.html?example=05-Multiply [3] - http://w3id.org/lindt/custom_datatypes#implementation [4] - https://github.com/unitsofmeasurement/uom-systems/tree/master/ucum-java8 [5] - https://ci.mines-stetienne.fr/lindt/spec.html [6] - https://ci.mines-stetienne.fr/sparql-generate/