RDFS allows the definition of subproperties.
true
SHACL is equivalent to OWL
false
Mathematically, a knowledge graph can be described as a directed labelled graph
Blank nodes can occur in any position of an RDF triple.
only as subjects and objects, not as predicates
RML allows to specify XML sources
N-Triples are a valid serialization format of RDF triples
Evaluating a SPARQL query with entailment regimes always leads to fewer results
it can lead to more results
? is used to denote blank nodes in RDF.
it is denoted with a blank node identifier such as _:blankNode
OWL ontologies can be exchanged as RDF documents
The "Open World Assumption" allows us to consider missing information as negative information.
the “Closed World Assumption”
Using RDFS, we can express the fact that every child (A) has exactly one father (B)
in OWL we could
RDFS allows multiple inheritance for classes and properties
The result type of an ASK query is an RDF graph or triple
a boolean
SPARQL uses primary keys for subgraph merging.
The result type of a CONSTRUCT query is a Boolean
an RDF graph / a triple
Internationalized Resource Identiers (IRIs) are a subset of Uniform Resource Identiers (URIs).
A SPARQL query can be evaluated on the default graph.
R2RML is a superset of RML
RML is a superset of R2RML
SPARQL supports JOIN clauses
RDFS provides a wider range of ontological constructs than OWL
OWL can do more than RDFS
On the subject position of an RDF triple, any RDF term is allowed
IRI or blank node
In SPARQL queries, SELECT DISTINCT filters out duplicate solution mappings.
SPARQL queries are always translated into SQL and then executed on a relational database.
In a SPARQL query, only solutions that match all of the FILTER expressions are returned
A resource can only be a member (hint: type) of a single class
e.g.: Subclasses
Blank nodes have URIs
Domain and range of properties can be specied in RDFS.
In OWL, the range of object properties are instances of classes
The result type of a CONSTRUCT query is an RDF graph or triple
SPARQL Is primarily a query language for relational databases
for RDF graphs
A SPARQL query can only be evaluated on the default graph
can be evaluated on multiple graphs
SHACL is mainly targeted at XML
R2RML allows to specify XML sources
for RDB (databases)
RDFS is a way to specify ontologies
OWL is based on a form of logic
description logic
OWL is a way to specify ontologies
Which data is processed with OpenRefine to obtain RDF
Tabular data (CSV)
Which data is processed with R2RML to obtain RDF?
Relational Data (Databases)
Which data is processed with RML to obtain RDF?
Structured data (JSON, XML, CSV, …)
What is an ontology?
Formal, explicit specification of a shared conceptualization
What is a taxonomy?
controlled vocabulary in a hierarchical structure
An ontology is an extended taxonomy
Which steps are necessary to create an ontology?
The process is not linear and involves the following 8 steps:
Determining Scope
Consider Reuse
Enumerate Terms
Define Classes & Taxonomy
Define Properties
Define Constraints
Create Instance
Check for Anomalies
Literals have URIs
only text
What does a plain literal in RDF consist of?
lexical form (value) + optional language tag
What does a typed literal in RDF consist of?
A string + URIref identifying the datatype it should be interpreted as
RDF blank node represent unnamed resources
What is the AAA slogan?
(On the Web) “Anyone can say Anything about Any topic”
How does RDFS extend RDF?
Defines taxonomy for RDF
What property restrictions are there in advanced OWL?
restrictions on values
restrictions on cardinality
The SELECT query returns variables and their bindings directly
The DESCRIBE query returns an RDF graph containing data about a resource
Unlike the DISTINCT keyword, REDUCED does not guarantee elimination of duplicates
In SPARQL 1.1, what do CREATE, LOAD, CLEAR, and DROP do?
CREATE creates an empty graph in the graph store
LOAD reads the content of a document into a graph in the graph store
CLEAR removes all triples in one or more graphs
DROP removes the graph from the graph store
What is SHACL for?
Validating RDF graphs against a set of conditions
What are the data graph and the shapes graph in SHACL
Data graph: the graph to be validated
Shapes graph: graph with conditions as shapes
What type of shapes are there in SHACL?
Node Shapes (validating the focus nodes)
Property Shapes (validating properties of focus nodes)
What are ways of knowledge graph creation?
Template-based on-the-fly generation
with mapping and transformation tools
On-the-fly generation of knowledge graphs doesn’t create links between resources
Openrefine is bad for messy data
it is a tool for messy data
Openrefine’s key feature is to apply transformations over many cells in bulk
Which two components are unique to RML (compared to R2RML)
Iterator
Reference Formulation
YARRRML is a superset of YAML
a subset
YARRRML can produce R2RML and RML mappings
What does an annotation consists of?
(s, o, p, c) where …
… s is the subject (the annotated data)
… o is the object (the annotating data)
… p is the predicate (the annotation relation)
… c is the context in which the annotation is made
RDF graphs can be stored on a centralized or a distributed system
Last changed20 days ago