Lecture 7 Flashcards
What is the purpose of knowledge graphs?
Knowledge graphs connect instances, classes, and their properties using relations for structured reasoning and data representation.
What are the components of an ontology?
Instances, classes, attributes, and relations.
What is an ontology?
An explicit specification of a shared conceptualization tied to a specific domain or task.
What is the purpose of RDF in knowledge graphs?
RDF provides a standardized vocabulary for modeling knowledge graphs using triples.
What is a triple in RDF?
A triple consists of a subject, predicate, and object, representing relationships between entities.
What is the role of entailment in RDF?
Entailment allows reasoning over RDF triples by applying rules to infer new relationships or data.
What is the domain of a relation in an ontology?
The class of objects the relation applies to.
What is the range of a relation in an ontology?
The class of objects the relation produces as a result.
What is SPARQL used for?
SPARQL is a query language for retrieving and manipulating data in knowledge graphs.
What is a subclass in an ontology?
A class that inherits properties from its parent class.
What is the difference between forward chaining and backward chaining?
Forward chaining derives all possible conclusions from the knowledge base, while backward chaining works backward from a goal to determine its validity.
What is monotonicity in reasoning?
The property that adding new information to a knowledge base does not invalidate existing entailed conclusions.
What is the purpose of reasoning with rules in knowledge graphs?
To derive new facts or relationships based on existing data and logical rules.
What is the difference between propositional logic and knowledge graphs?
Propositional logic evaluates truth values, while knowledge graphs model structured relationships between entities.
What are the benefits of knowledge graphs over propositional logic?
Knowledge graphs are scalable, can represent complex relationships, and are context-independent.
What are the limitations of propositional logic?
Limited expressive power and inefficiency in handling partial or infinite domains.
What is the closure set in forward chaining?
The set of all facts derivable from the knowledge base.
How does backward chaining reduce complexity?
It focuses only on deriving specific facts rather than exploring all possible derivations.
What is the purpose of entailment rules in RDF?
To infer new facts by applying logical rules to triples in the graph.
What is the difference between domain and range in RDF?
Domain specifies the class the relation applies to, and range specifies the class it relates to.
What is the significance of class disjointness in ontologies?
It ensures that instances of one class cannot belong to another disjoint class.
What are axioms in ontologies?
Statements or rules defining properties and relationships between classes and instances.
What is the significance of universal and existential restrictions in ontologies?
They define constraints on the relationships between classes and their instances.
What is a knowledge base (KB) in the context of reasoning?
A collection of structured facts and rules used for reasoning and inference.
What is the difference between declarative and procedural knowledge?
Declarative knowledge describes facts, while procedural knowledge describes how to perform tasks.
What are the advantages of rule-based reasoning?
It is explicit, compositional, and allows reasoning over structured knowledge.
What is the role of SPARQL in reasoning with knowledge graphs?
It retrieves and manipulates data by querying triples in the graph.
What does RDF(S) stand for?
Resource Description Framework (Schema), a framework for describing and structuring metadata.
What is the role of owlrl in knowledge graphs?
It provides reasoning capabilities for RDF and OWL (Web Ontology Language) datasets.
What is the purpose of defining a taxonomy in ontology development?
To organize terms into a hierarchy of classes and subclasses.
