Knowledge Graphs and Linked Data

Question 1

What is the purpose of publishing KG data on the web?

Answer 1

To make it publicly available and accessible.

Question 2

What does Linked Open Data aim to overcome?

Answer 2

Merging siloed data.

Question 3

What is the main idea behind Linked Data?

Answer 3

Use the Web to create a global dataspace for consistent data sharing.

Question 4

What technology is used to publish structured data on the Web in Linked Data?

Answer 4

RDF (Resource Description Framework).

Question 5

Why are links stated explicitly between data items?

Answer 5

To define relationships and properties clearly across datasets.

Question 6

Why not just use CSV, XML, or relational data?

Answer 6

Because Linked Data focuses on shared semantics, not just syntax.

Question 7

What level of interpretability does Linked Data aim for?

Answer 7

Semantic level, not surface-level parsing.

Question 8

What is the Web-based model Linked Data relies on?

Answer 8

A data (RDF) and naming (URI) model.

Question 9

Why use HTTP-based identifiers?

Answer 9

To enable dereferencing via web mechanisms like GET and POST.

Question 10

What do dereferenced URIs return?

Answer 10

Useful structured information in standard formats like RDF.

Question 11

What is Linked Data trying to express between resources?

Answer 11

Relations and links accessible via IRIs.

Question 12

What are the 4 Linked Data principles?

Answer 12

1. Use URIs to identify things; 2. Use HTTP URIs; 3. Provide useful info; 4. Link to other URIs where possible

Question 13

What should URIs be used to name?

Answer 13

Everything including tangible and abstract concepts.

Question 14

What does using URIs for all things extend?

Answer 14

The scope of the Web to encompass all objects and concepts.

Question 15

Why must a URI be dereferenceable?

Answer 15

To retrieve useful data using web protocols.

Some URIs don’t point to any specific data, which is not ideal.

When you do an HTTP GET/type a URL into your browser, a result is returned, an RDF description in the best case!

Question 16

What protocol is used to dereference URIs?

Answer 16

HTTP.

Question 17

Are dereferenceable URIs mandatory in Linked Data?

Answer 17

No, they are recommended but not required.

Question 18

What should dereferenced URIs provide?

Answer 18

RDF descriptions using standard formats.

Question 19

Why is RDF used as a data model?

Answer 19

Because it’s a simple, graph-based model for structured data.

Question 20

What does linking to other URIs help with?

Answer 20

Discovery of related data on the Web.

Question 21

How are links between things expressed?

Answer 21

With RDF properties that describe the relationship type.

Question 22

What happens when RDF links connect different namespaces?

Answer 22

They connect resources in different datasets.

Question 23

What is the benefit of connecting data sets?

Answer 23

Creating a single global dataspace for navigation and integration.

Question 24

How does Linked Data differ from the classic Web?

Answer 24

It links real-world concepts, not just documents.

Question 25

What is the significance of using shared web mechanisms?

Answer 25

They help software navigate linked resources like humans navigate the Web.

Question 26

What does Tim berners lee mean by Open Data?

Answer 26

Data published with liberal licenses, freely usable and shareable.

Question 27

What is Linked Open Data?

Answer 27

The combination of Linked Data principles with Open Data publication.

Question 28

Why is Linked Open Data important?

Answer 28

It helps debunk misinformation by ensuring open and connected data.

Question 29

What is DBPedia?

Answer 29

An RDFised version of Wikipedia, serving as a central dataset.

Question 30

What are some big Linked Data datasets?

Answer 30

FOAF, US Census data.

Question 31

How are datasets categorised?

Answer 31

By colour representing shared subjects or characteristics.

Question 32

What does FOAF describe?

Answer 32

Persons, their properties, and their relationships.

Question 33

What is the transport mechanism for Linked Data?

Answer 33

HTTP protocol.

Question 34

What is used to represent data and the model in Linked Data?

Answer 34

RDF

Question 35

What identifies resources in Linked Data?

Answer 35

URIs.

Question 36

What defines the semantics of schemas?

Answer 36

Vocabularies and ontologies.

Question 37

What query language is used in Linked Data?

Answer 37

SPARQL

Question 38

What aggregates content from different namespaces?

Answer 38

Mashups

Question 39

What are some native RDF triplestores?

Answer 39

Sesame, Jena, Owlim.

Question 40

What do Linked Data browsers do?

Answer 40

Explore datasets and navigate between them.

Question 41

What are Linked Data mashups?

Answer 41

Sites that combine multiple Linked Data sources.

Question 42

What is the purpose of Linked Data search engines?

Answer 42

To search for Linked Data.

Question 43

What are persistent URIs?

Answer 43

URIs that cannot be changed, ensuring consistent identification of data.

Question 44

What is a downside of current Linked Data growth?

Answer 44

Some data is irregularly updated or already available in other formats.

Question 45

Why is API availability a concern in Linked Data?

Answer 45

APIs may not support RDF or may limit access to the data.

Question 46

What risk arises from not linking published data?

Answer 46

Creating RDF silos.

Question 47

What do we need more of to support Linked Data?

Answer 47

Applications, tools, and openly licensed data with provenance.

Question 48

What are some open issues in Linked Data applications?

Answer 48

Integration difficulties, data discovery, and interface usability.

Question 49

What is the 4-step process to create Linked Data?

Answer 49

1) Add semantics to the data 2) Model general world knowledge 3) Acquire new knowledge from inference 4) Query consistent information from different source

Question 50

What is step 1 in creating Linked Data?

Answer 50

Add semantics to the data. Can go further by identifying classes of individuals of the same type and relationships existing between entities in the domain and individuals.

Question 51

What is step 2 in creating Linked Data?

Answer 51

Model general world knowledge Now have instances of classes and relationships between classes.

Question 52

What is step 3 in creating Linked Data?

Answer 52

Acquire new knowledge through inference using RDFs/OWL.

Question 53

Give an example of inference from RDFs

Answer 53

If Shakespeare is a poet and all poets are writers, Shakespeare is a writer.

Question 54

What is step 4 in creating Linked Data?

Answer 54

Query information from different sources.

Question 55

Give an example query for Linked Data

Answer 55

List all persons from Wikipedia, IMDB, Wikidata, or British Library.

Question 56

What is an example of a co-authorship query?

Answer 56

List all authors who co-authored with a co-author of Paul Erdoss.