Basic definitions RDF is a concept. RDF is also a NAME of a vocabulary. RDFS is a NAME of another vocabulary. “ontology” is just a SYNONYM of the term “vocabulary”. Explanations RDF is a concept RDF is a concept or a way of describing things. The concept of RDF is that you are describing / … Read more
Gephi was already mentioned, but I’ll incode screenshots and a short description here. Gephi can not just visualize graphs but also supports analyzing, layouting and further importing and exporting. There is a Semantic Web Import Extension that allows you to directly query (via SPARQL) or import RDF data. https://wiki.gephi.org/index.php/SemanticWebImport (You can install it directly within … Read more
By far the best RDF linked open data visualization tool that I’ve come across is LodLive: http://en.lodlive.it/ It knows of numerous SPARQL endpoints, including DBpedia. I’ve previously implemented a web based RDF authoring tool that hooks into it: https://github.com/robstewart57/discover-me-semantically .
The viewpoint of the CTO of a company that extensively uses RDF Triplestores commercially: Schema flexibility – it’s possible to do the equivalent of a schema change to an RDF store live, and without any downtime, or redesign – it’s not a free lunch, you need to be careful with how your software works, but … Read more
The best explanation is by example. Try googling for all cars advertised on the web with engines smaller than 2.0 litres that run unleaded, and have an mp3 connection and can been seen in a showroom conveniently accessible by public transport from my house. Google just won’t be able to help you with that query, … Read more
Differences between Microdata and RDFa While there are many (technical, smaller) differences, here’s a selection of those I consider important (used my answer on Webmasters as a base). Specifications As W3C’s HTML WG found no volunteer to edit the Microdata specification, it is now merely a W3C Group Note (see history), which means that there … Read more
Thanks for this interesting question. There are few more things to consider here. What is a pair? Two elements together. So we need a tag for this. Let’s say it is pair tag. <pair></pair> The pair contains the key, and the corresponding value: <pair><key>keyname</key><value>value</value></pair> Then, we need to list the pairs: <pairlist> <pair><key>keyname</key><value>value</value></pair> <pair><key>keyname</key><value>value</value></pair> </pairlist> … Read more
The semantic web comes in layers. This is a quick summary of the ones I think you’re interested in. Update: Please note that RDFS is used to define the structure of the data, not OWL. OWL describes semantic relationships which normal programming, such as a C struct, isn’t fussed about and is closer to AI … Read more