semantic-web

问题 I'm playing with the idea of using SPARQL to identify conceptual overlap between things. Take movies for example (LinkedMDB data), if I have a movie, "The Matrix" and my goal is to list movies that are similar to that movie, I would probably start by doing the following: The Matrix get genre get actors get director get location etc And then using the things I identified in the matrix, I would query for things with those properties (pseudo-query) SELECT movie, genre, director, location, actors

问题 In Wikidata (Wikidata SPARQL endpoint), is there a way to order the SPARQL query results with something like a PageRank? SELECT DISTINCT ?entity ?entityLabel WHERE { ?entity wdt:P31 wd:Q5. SERVICE wikibase:label { bd:serviceParam wikibase:language "en" . } } LIMIT 100 OFFSET 0 Can we specify a field to order the results by and that field expresses that the entity at the top is more notable/important/recognizable that the following one and so on? 回答1: It seems that PageRank does not make much

问题 What to use for poem? pre blockquote code something else? 回答1: Don't use code (unless computer code is part of the poem). Don't use blockquote (unless you quote a poem). white space / line breaks: pre or br You may use the pre element. The spec gives an (informative) example: The following shows a contemporary poem that uses the pre element to preserve its unusual formatting, which forms an intrinsic part of the poem itself. <pre> maxling it is with a heart heavy that i admit loss of a feline

问题 Is it possible in protege (Thus in owl) to describe a class depending if it has some properties? For example I have a class Home , and I want to say that every instance that has property1 and property2 and property2 is considered an instance of that class? 回答1: Suppose you have a class Duck and you want to say that if something walks like a Duck, and talks like a Duck, then it is a Duck. You can do that with a class axiom: ((walksLike some Duck) and (talksLike some Duck)) SubClassOf Duck A

问题 SPARQL property path queries of arbitrary length require using specific properties. I want to query and find any path starting from a resource and ending in another resource. For example: SELECT ?p WHERE { :startNode ?p* :endNode } where ?p* specifies a path. Is there a way of doing this? 回答1: You're right that you can't use variables in property path expressions. There are a few things that you can do, though, that might help you. A wildcard to check whether a path exists You can use a

问题 I am trying to grasp the concept of Semantic Web. I am finding it hard to understand what exactly is the difference between RDF and OWL. Is OWL an extension of RDF or these two are totally different technologies? 回答1: 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

问题 I'm looking for a clear approach to use SWRL clearly in virtuoso server. For example, I designed an ontology using Protege 4.3 and I wrote the SWRL rules using Rules tab in Protege. Product(?P),hasName(?P,?N),inGroupB(?P,?B)->hasBug(?P) I uploaded my RDF data (~3GB) into Virtuoso server, along with the Ontology schema. I tried to recall the data that is supposed to be inferred based on the Rules in the ontology but the query return empty results. Example of the SPARQL query that it should

问题 We've installed Fuseki2 as a service at a Ubuntu-server and its works fine: sudo service fuseki status * Fuseki is running with pid: 915 I now can go to http://xyz:30303/manage.html (where xyz it the ip-address of the server) and it shows the Manage datasets screen, but nothing happens when I click add new dataset . Console browser (and also http://xyz:3030/$/server ) gives " Failed to load resource: the server responded with a status of 403 (Access denied : only localhost access allowed) "

问题 Is it possible to have a list in front of an expression in OWL? Something like: ( :Dairy :Egg :Nut ) rdfs:subClassOf :FoodGroup . or: :Dairy , :Egg , :Nut rdfs:subClassOf :FoodGroup . Or in general, is there a syntactic sugar for a group of expressions of the type?: :Diary rdfs:subClassOf :FoodGroup . :Egg rdfs:subClassOf :FoodGroup . :Nut rdfs:subClassOf :FoodGroup . 回答1: Turtle In Turtle, there are no subject lists that would be similar to object lists. It is possible to write something

问题 I'm making that SPARQL query: PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#> SELECT ?label WHERE { <http://pt.dbpedia.org/resource/Brasil> rdfs:label ?label.} and I don't get any results for ?text . I checked that URI on my browser and found the rdfs:label property there. Is that problem caused by the URI form http://pt.dbpedia.org/ ? I've already used the same query with IRIs starting with http://dbpedia.org/resource/ , e.g.,