Distributed Knowledge Graphs 1

UNC SDIS, INLS 620, Fall 2026

August 18
Introduction to the course

Total amount of required reading for this meeting: 1,000 words

An introduction to the course: what knowledge graphs are, what makes them distributed, and how we will work together this semester.

πŸ“– To read before this meeting:

  1. Recurse Center. “Social Rules,” n.d. https://www.recurse.com/social-rules.
    1,000 words

August 20
Git and GitHub

View notes Updated Thursday 8/20 10:36 AM

Git is a distributed version control system, and GitHub hosts Git repositories on the Web. Each assignment is distributed as a repository that is forked for you; we look at how to clone your fork, and how to stage, commit, and push your work back to it.

πŸ“– To read before this meeting:

  1. GitHub, Inc. “Start Your Journey: Learn the Basics of GitHub.” GitHub Docs, 2024. https://docs.github.com/en/get-started/start-your-journey.

August 25
Visual Studio Code and Codespaces

Total amount of required viewing for this meeting: 14 minutes

Visual Studio Code is the editor we will use throughout the course. A codespace is a preconfigured Linux development environment that runs in a container, either remotely on GitHub or locally using Docker.

πŸ“Ί To view before this meeting:

  1. Microsoft, β€œLearn Visual Studio Code in 7min.”

    View. 7 minutes
    Viewing tips

    You can follow along at https://vscode.dev.

  2. Microsoft, β€œUsing Git with Visual Studio Code.”

    View. 7 minutes

August 25
Hello world assignment available

August 27
Forms of data

Total amount of required reading for this meeting: 12,800 words

Data can be structured as blobs, sets, lists, dictionaries, trees, or graphs, and each of these structures makes different questions easy to ask. We compare the tabular, relational, meta-markup, and graph metamodels built on top of them.

πŸ“– To read before this meeting:

  1. Shaw, Ryan. “The Forms of Descriptions (Part 1),” 2022. PDF.
    4,300 words
  2. Shaw, Ryan. “The Forms of Descriptions (Part 2),” 2022. PDF.
    8,500 words

August 27
Hello world assignment due

September 1
(Semantic) data modeling I

Total amount of required viewing for this meeting: 19 minutes

Data modeling is the design of a formal language intended to aid communication and mediate among different purposes and perspectives.

πŸ“Ί To view before this meeting:

  1. Posner, Miriam. What Is Linked Open Data?, 2021.

    View. 19 minutes

September 3
(Semantic) data modeling II

Total amount of required reading for this meeting: 8,000 words

The Semantic Web is a vision of the Web as a space for sharing data rather than documents. We consider what it means to model data so that it can be combined with data modeled by other people for other purposes.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “What Is the Semantic Web?” In Semantic Web for the Working Ontologist, 3rd ed., 1–18. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    8,000 words

September 3
Data modeling assignment available

September 8
(Semantic) data modeling III

Total amount of required reading for this meeting: 7,000 words

Semantic modeling makes the meaning of data explicit, so that data can be interpreted consistently by parties who never coordinated with one another.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “Semantic Modeling.” In Semantic Web for the Working Ontologist, 3rd ed., 19–35. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    7,000 words

September 10
The Web I

Total amount of required reading for this meeting: 10,200 words

The (World Wide) Web is an Internet-scale distributed hypermedia system. It exists by means of voluntary compliance with open communication protocols and data format standards.

πŸ“– To read before this meeting:

  1. Richardson, Leonard, and Mike Amundsen. “Surfing the Web.” In RESTful Web APIs, 1–16. Sebastopol, California: O’Reilly, 2013. PDF.
    4,500 words
  2. Hogan, Aidan. “Introduction.” In The Web of Data, 1–14. Springer, 2020. PDF.
    5,700 words
    Reading tips

    Focus on section 1.2 (β€œThe Current Web”), pages 6–14.

September 15
The Web II

Total amount of required reading for this meeting: 4,900 words

A closer look at the machinery of the Web: resources identified by URIs, representations transferred over HTTP, and the roles played by DNS, HTTP methods, status codes, and content negotiation.

πŸ“– To read before this meeting:

  1. Richardson, Leonard, and Mike Amundsen. “Resources and Representations.” In RESTful Web APIs, 29–43. Sebastopol, California: O’Reilly, 2013. PDF.
    4,900 words
  2. Optional
    Allemang, Dean, Jim Hendler, and Fabien Gandon. “Linked Data.” In Semantic Web for the Working Ontologist, 3rd ed., 85–118. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    11,600 words

September 15
Data modeling assignment due

September 17
RDF: terms, triples, graphs I

Total amount of required reading for this meeting: 7,000 words

The Resource Description Framework (RDF) is a conceptual model for structuring information into triples that can be combined into graphs.

πŸ“– To read before this meeting:

  1. DuCharme, Bob. “What Is RDF?,” June 27, 2021. https://www.bobdc.com/blog/whatisrdf/.
    2,100 words
  3. Schreiber, Guus, and Yves Raimond. “RDF Data Model.” In RDF 1.1 Primer. W3C, 2014. https://www.w3.org/TR/rdf11-primer/#section-data-model.
    1,300 words

September 17
The Web assignment available

September 22
RDF: terms, triples, graphs II

Total amount of required reading for this meeting: 7,000 words

The three kinds of node found in an RDF graphβ€”URIs, literals, and blank nodesβ€”and the properties that relate them. We also look at namespaces and CURIEs, and at how RDF datasets keep track of graphs that change over time.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “RDF—The Basis of the Semantic Web.” In Semantic Web for the Working Ontologist, 3rd ed., 37–67. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    7,000 words
  2. Optional
    Hogan, Aidan. “Resource Description Framework.” In The Web of Data, 59–109. Springer, 2020. PDF.
    10,000 words
  3. Optional
    W3C. “RDF 1.1 Concepts and Abstract Syntax,” February 25, 2014. https://www.w3.org/TR/rdf11-concepts/.

September 24
RDF: serializations I

Total amount of required reading for this meeting: 5,100 words

Because RDF is a purely conceptual model, it does not specify how data should be written down or serialized. There are several alternative standards for serialization.

πŸ“– To read before this meeting:

  1. Schreiber, Guus, and Yves Raimond. “Writing RDF Graphs.” In RDF 1.1 Primer. W3C, 2014. https://www.w3.org/TR/rdf11-primer/#section-graph-syntax.
    2,900 words
  2. Allemang, Dean, Jim Hendler, and Fabien Gandon. “Alternatives for Serialization.” In Semantic Web for the Working Ontologist, 3rd ed., 68–63. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    2,200 words

September 29
RDF: serializations II

Total amount of required reading for this meeting: 5,000 words

A survey of the standard RDF syntaxesβ€”N-Triples, Turtle, RDF/XML, and JSON-LDβ€”and the tradeoffs among them, including what JSON-LD offers to developers already working with JSON.

πŸ“– To read before this meeting:

  1. Hogan, Aidan. “RDF Syntaxes.” In The Web of Data, 94–109. Springer, 2020. PDF.
    5,000 words
  2. Optional
    Sporny, Manu. What Is JSON-LD?, 2012. https://www.youtube.com/watch?v=vioCbTo3C-4.

September 29
The Web assignment due

October 1
RDF Schema and RDF vocabularies I

Total amount of required reading for this meeting: 2,200 words

RDF Schema is a data modeling language layered on top of the basic RDF conceptual model. It provides additional tools for describing classifications and collections of resources.

πŸ“– To read before this meeting:

  1. DuCharme, Bob. “What Is RDFS?,” July 25, 2021. https://www.bobdc.com/blog/whatisrdfs/.
    1,500 words
  2. Schreiber, Guus, and Yves Raimond. “RDF Vocabularies.” In RDF 1.1 Primer. W3C, 2014. https://www.w3.org/TR/rdf11-primer/#section-vocabulary.
    700 words

October 6
Well-being day

Due to the well-being day, we will not meet today.

October 8
RDF Schema and RDF vocabularies II

Total amount of required reading for this meeting: 11,300 words

The core RDF Schema vocabulary: classes and their instances, the subclass and subproperty relations, and the domains and ranges of properties. We also look at containers, collections, and reification.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “RDF Schema.” In Semantic Web for the Working Ontologist, 3rd ed., 201–32. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    11,300 words
  2. Optional
    Hogan, Aidan. “RDF Schema and Semantics.” In The Web of Data, 111–83. Springer, 2020. PDF.
    25,100 words
  3. Optional
    W3C. “RDF Schema 1.1,” February 25, 2014. https://www.w3.org/TR/rdf-schema/.
    4,000 words

October 8
RDFS assignment available

October 13
Wikidata and Wikibase I

Total amount of required reading for this meeting: 5,100 words

Wikidata is a free and openly editable knowledge base that is published as RDF. Wikibase is the software it runs on.

πŸ“– To read before this meeting:

  1. Vanderbilt University. “Learn Wikidata.” Accessed January 7, 2022. https://www.learnwikidata.net/.
  2. Vrandečić, Denny, and Markus Krötzsch. “Wikidata: A Free Collaborative Knowledgebase.” Communications of the ACM 57, no. 10 (September 23, 2014): 78–85. https://doi.org/10.1145/2629489.
    5,100 words

October 15
Fall break

Due to fall break, we will not meet today.

October 20
Wikidata and Wikibase II

Total amount of required reading for this meeting: 6,800 words

The Wikidata data model: items, properties, and the statements that relate them, along with the qualifiers, references, and datatypes a statement may involve, and how this model is mapped onto RDF.

πŸ“– To read before this meeting:

  1. Wikidata. “Help:Items,” n.d. https://www.wikidata.org/wiki/Help:Items.
    1,900 words
  2. Wikidata. “Help:Properties,” n.d. https://www.wikidata.org/wiki/Help:Properties.
    1,200 words
  3. Wikidata. “Help:Statements,” n.d. https://www.wikidata.org/wiki/Help:Statements.
    1,800 words
  4. Wikidata. “Help:Data Type,” n.d. https://www.wikidata.org/wiki/Help:Data_type.
    1,900 words
  5. Optional
    Wikibase. “Wikibase/DataModel,” n.d. https://www.mediawiki.org/wiki/Wikibase/DataModel.
    7,200 words
  6. Optional
    Wikibase. “Wikibase/Indexing/RDF Dump Format,” n.d. https://www.mediawiki.org/wiki/Wikibase/Indexing/RDF_Dump_Format.
    4,800 words

October 20
RDFS assignment due

October 22
SPARQL I

Total amount of required reading for this meeting: 19,200 words

The SPARQL Protocol and RDF Query Language (SPARQL) is a query language for RDF.

πŸ“– To read before this meeting:

  1. DuCharme, Bob. “Jumping Right in: Some Data and Some Queries.” In Learning SPARQL: Querying and Updating with SPARQL 1.1, 2nd ed., 1–17. Sebastopol: O’Reilly Media, 2013. PDF.
    5,100 words
  2. DuCharme, Bob. “SPARQL Queries: A Deeper Dive.” In Learning SPARQL: Querying and Updating with SPARQL 1.1, 2nd ed., 47–102. Sebastopol: O’Reilly Media, 2013. PDF.
    14,100 words

October 27
Ryan is out of town

I will be be out of town, so we will not meet today.

October 29
SPARQL II

Total amount of required viewing for this meeting: 45 minutes

Total amount of required reading for this meeting: 2,200 words

Writing SPARQL queries: basic graph patterns and the variables they bind, then ordering, limiting, and filtering results, matching alternatives with UNION, and handling incomplete data with OPTIONAL.

πŸ“Ί To view before this meeting:

  1. Wikimedia Foundation. Querying Wikidata with SPARQL for Absolute Beginners, 2018.

    View. 45 minutes
    Viewing tips

    You need not watch the entire 111 minutes… the first 45 minutes covers the most important things.

πŸ“– To read before this meeting:

  1. “A Gentle Introduction to the Wikidata Query Service.” In Wikidata, n.d. https://www.wikidata.org/wiki/Wikidata:SPARQL_query_service/A_gentle_introduction_to_the_Wikidata_Query_Service.
    2,200 words
  2. Optional
    Wikidata. “Wikidata:SPARQL Query Service/Queries,” n.d. https://www.wikidata.org/wiki/Wikidata:SPARQL_query_service/queries.

October 29
Wikidata and SPARQL assignment available

November 3
SPARQL III

Total amount of required reading for this meeting: 18,900 words

More of SPARQL: property paths for matching routes of arbitrary length through a graph, grouping and aggregation, and CONSTRUCT queries that return graphs rather than tables. We also look at querying Wikidata for labels, qualifiers, and references.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “Querying the Semantic Web—SPARQL.” In Semantic Web for the Working Ontologist, 3rd ed., 119–80. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    18,900 words
  2. Optional
    Hogan, Aidan. “SPARQL Query Language.” In The Web of Data, 323–448. Springer, 2020. PDF.
    37,500 words
  3. Optional
    W3C. “SPARQL 1.1 Query Language,” March 21, 2013. https://www.w3.org/TR/sparql11-query/.

November 5
Shape constraints I

Total amount of required reading for this meeting: 19,800 words

Shape constraint languages (SHACL and ShEx) allow us to prescribe a certain β€œshape” for a graph, by requiring or forbidding certain patterns of triples.

πŸ“– To read before this meeting:

  1. Hogan, Aidan. “Shape Constraints and Expressions.” In The Web of Data, 449–513. Springer, 2020. PDF.
    19,800 words

November 5
Wikidata and SPARQL assignment due

November 10
Shape constraints II

Shape constraint languages (SHACL and ShEx) allow us to prescribe a certain β€œshape” for a graph, by requiring or forbidding certain patterns of triples.

πŸ“– To read before this meeting:

  1. Wikidata. “Wikidata:WikiProject Schemas,” n.d. https://www.wikidata.org/wiki/Wikidata:WikiProject_Schemas.

November 10
SHACL and OWL assignment available

November 12
Shape constraints III / OWL I

We finish with shape constraints and begin the Web Ontology Language (OWL), introducing inverse, transitive, and symmetric properties and the distinction between object and datatype properties, by looking at how they are used to define the Simple Knowledge Organization System (SKOS).

πŸ“– To read before this meeting:

  1. Optional
    Allemang, Dean, Jim Hendler, and Fabien Gandon. “Extending RDF: RDFS and SHACL.” In Semantic Web for the Working Ontologist, 3rd ed., 181–200. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    7,400 words

November 17
OWL II

Total amount of required reading for this meeting: 12,400 words

The Web Ontology Language (OWL) is a data modeling language layered on top of RDF Schema (which is why some parts of OWL are referred to as β€œRDF-Plus.” OWL enables more complex inferences to be drawn from RDF data.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “RDFS-Plus.” In Semantic Web for the Working Ontologist, 3rd ed., 233–69. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    12,400 words

November 19
OWL III

Total amount of required reading for this meeting: 22,600 words

Beyond RDFS-Plus: the basic OWL constructs for describing classes in terms of set operations and cardinality restrictions, and what is involved in using these vocabularies in the wild.

πŸ“– To read before this meeting:

  1. Allemang, Dean, Jim Hendler, and Fabien Gandon. “Using RDFS-Plus in the Wild.” In Semantic Web for the Working Ontologist, 3rd ed., 271–302. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    12,600 words
  2. Allemang, Dean, Jim Hendler, and Fabien Gandon. “Basic OWL.” In Semantic Web for the Working Ontologist, 3rd ed., 319–51. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    10,000 words
  3. Optional
    Allemang, Dean, Jim Hendler, and Fabien Gandon. “SKOS—Managing Vocabularies with RDFS-Plus.” In Semantic Web for the Working Ontologist, 3rd ed., 303–18. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    5,700 words
  4. Optional
    Allemang, Dean, Jim Hendler, and Fabien Gandon. “Counting and Sets in OWL.” In Semantic Web for the Working Ontologist, 3rd ed., 353–89. ACM Books 33. Association for Computing Machinery, 2020. PDF.
    11,500 words
  5. Optional
    Hogan, Aidan. “Web Ontology Language.” In The Web of Data, 185–322. Springer, 2020. PDF.
    49,300 words

November 24–26
Thanksgiving

Due to Thanksgiving, we will not meet this week.

December 1
Semantic data modeling in practice

December 1
SHACL and OWL assignment due