What are and why are we studying ontologies

1. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 What are Ontologies and why is one studying it? Prof. Dr. Harald Sack Fraunhofer IWM Freiburg, 21 October 2019

2. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 2 From Data to Knowledge Erich Kuithan: Schiller auf dem Weg zu seiner Antrittsvorlesung, 1909/10 [1] “All our knowledge finally, as all the world's wise men agree, amounts to a conventional deception with which, however, the strictest truth can exist.” Friedrich Schiller, Theoretical Essays and Philosophical Letters (1786)

3. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 3 From Data to Knowledge 33.6

4. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 4 From Data to Knowledge 33.6 m

5. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 5 From Data to Knowledge 33.6m Baleanoptera musculus 33.6 m maxLength BaleanopteraMusculus ⊑ Animal ⊓ ∀maxLength.≤33.6 Animal is a

6. Information Service Engineering , Prof. Dr. Harald Sack, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & AIFB - Karlsruhe Institute of Technology Data [2]

7. Information Service Engineering , Prof. Dr. Harald Sack, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & AIFB - Karlsruhe Institute of Technology Information [3]

8. Information Service Engineering , Prof. Dr. Harald Sack, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & AIFB - Karlsruhe Institute of Technology Data transforms to information by convention, information to knowledge by cognition, and knowledge to wisdom by contemplation Knowledge [4]

9. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 9 Carol Kaelson/Jeopardy Productions Inc., via Associated Press From Data to Knowledge 9 DIKW Pyramid, Ackoff 1989 From Data to Knowledge evaluated understanding information enriched with semantics in usable form raw characters and symbols future novelty past experience

10. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 10 „People can‘t share knowledge if they don‘t speak a common language“ Thomas Davenport (1997) [5]

11. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 11 What is Knowledge? [5] Beliefs Truths Knowledge Traditional Definition: „Knowledge is a subset of all true beliefs“

12. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 12 ...to speak a common Language: ● common symbols and concepts (Syntax) ● agreement about their meaning (Semantics) ● classification of concepts (Taxonomy) ● associations and relations of concepts (Thesauri) ● rules and knowledge about which relations are allowed and make sense (Ontologies) [5]

13. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 13 Carol Kaelson/Jeopardy Productions Inc., via Associated Press 13 What is Ontology? „A theory of being, which tries to explain the being itself, by developing a system of universal categories and their intrinsic relationships...“ Philosophy Definition [6]

14. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 14 14 DIKW Pyramid What is an Ontology? „A theory of being, which tries to explain the being itself, by developing a system of universal categories and their intrinsic relationships...“ Computer Science Definition What is Ontology? [7] An ontology is an explicit, formal specification of a shared conceptualization. according to Thomas R. Gruber: A Translation Approach to Portable Ontology Specifications. Knowledge Acquisition, 5(2):199-220, 1993.

15. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 15 15 DIKW Pyramid What is an Ontology? „A theory of being, which tries to explain the being itself, by developing a system of universal categories and their intrinsic relationships...“ What is Ontology? [7] conceptualization: abstract model (domain, identified relevant concepts, relations) explicit: meaning of all concepts must be defined formal: machine understandable shared: consensus about ontology An ontology is an explicit, formal specification of a shared conceptualization. according to Thomas R. Gruber: A Translation Approach to Portable Ontology Specifications. Knowledge Acquisition, 5(2):199-220, 1993.

16. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 16

17. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 17 From Data to Knowledge 33.6m Baleanoptera musculus 33.6 m maxLength BaleanopteraMusculus ⊑ Animal ⊓ ∀maxLength.≤33.6 Animal subClass Of Miniature Example Ontology Class Class Property Constraint Animal ⊓ Plant ≡ ∅ subClass Of ThingAnimal ⊑ Thing Plant subClass Of Plant ⊑ Thing

18. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 18 From Data to Knowledge 33.6m Miniature Example Knowledge Base BaleanopteraMusculus Animal subClassOf Moby “Moby the Blue Whale” hasName AtlanticOcean livesIn is a BodyOfWater livesIn InstancesClasses is a Logical inference Logical inference is a

19. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 19 [7] Ontology Types and Categories according to their level of Generality Top-Level Ontology (Upper Ontology, Foundation Ontology) Task OntologyDomain Ontology Application Ontology specialized ontology focussed on a specific task and domain; often a specialization of both task and domain ontology; often specify roles played by domain entities for specific activity fundamental concepts according to a general activity or task; specializes terms introduced in top-level ontology (according to Guarino: Formal Ontology in Information Systems, 1998) general, cross domain ontologies; represent very general concepts as e.g., Time, Space, Event; independent of a specific domain or problem fundamental concepts according to a generic domain; specializes terms introduced in top-level ontology

20. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 20 Ontology Types and Categories according to their level of Generality Top-Level Ontology (Upper Ontology, Foundation Ontology) Task OntologyDomain Ontology Application Ontology specialized ontology focussed on a specific task and domain; often a specialization of both task and domain ontology; often specify roles played by domain entities for specific activity fundamental concepts according to a general activity or task; specializes terms introduced in top-level ontology (according to Guarino: Formal Ontology in Information Systems, 1998) general, cross domain ontologies; represent very general concepts as e.g., Time, Space, Event; independent of a specific domain or problem fundamental concepts according to a generic domain; specializes terms introduced in top-level ontology [8]

22. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 22 Ontology Types and Categories according to their level of Generality Top-Level Ontology (Upper Ontology, Foundation Ontology) Task OntologyDomain Ontology Application Ontology specialized ontology focussed on a specific task and domain; often a specialization of both task and domain ontology; often specify roles played by domain entities for specific activity fundamental concepts according to a general activity or task; specializes terms introduced in top-level ontology (according to Guarino: Formal Ontology in Information Systems, 1998) general, cross domain ontologies; represent very general concepts as e.g., Time, Space, Event; independent of a specific domain or problem fundamental concepts according to a generic domain; specializes terms introduced in top-level ontology

24. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 24 Ontology Types and Categories according to their level of Semantic Expressivity (according to Guarino: Formal Ontology in Information Systems, 1998) (according to Lassila and McGuiness:The Role of Frame-Based Representation on the Semantic Web, 2001 formalinformal - +Expressivity controlled Vocabulary Thesauri formal IS-A Frames general logical Constraints Glossaries informal IS-A formal Instance Value Restrictions Disjunctiveness, Inversiveness, Part-of... Terms Folksonomies formal Taxonomies First Order Logics Data Dictionaries Logic Programming Description Logics heavyweight Ontologies lightweight Ontologies

25. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 25 “It does not do to leave a live dragon out of your calculations, if you live near him.” J.R.R. Tolkien, The Hobbit or There and Back again (1937) [11]

26. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 26 Ontologies as Interpretations of Reality Various categories of animals from "a certain Chinese encyclopedia" according to Jorge Luis Borges: ● Those that belong to the emperor ● Embalmed ones ● Those that are trained ● Suckling pigs ● Mermaids (or Sirens) ● Fabulous ones ● Stray dogs ● Those that are included in this classification ● Those that tremble as if they were mad ● Innumerable ones ● Those drawn with a very fine camel hair brush ● Et cetera ● Those that have just broken the flower vase ● Those that, at a distance, resemble flies Jorge Luis Borges: The Analytical Language of John Wilkins (1942) Jorge Luis Borges (1899-1986) [12]

27. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 27 Great Ontology The Ontology Development Process SOMETHING [13]

28. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 28 The Ontology Design Process Management quality assurance control scheduling Support knowledge acquisition evaluation integration documentation merging configuration management alignment Design Oriented environment study feasibility study specification conceptualization formalization implementation maintenance use / re-use

29. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 29 Management Activities of the Ontology Design Process ● Scheduling ○ Identification of tasks/problems to solve ○ Arrangement/planning of tasks/problems to solve ○ Identification of required resources (time, memory, etc…) ● Control ○ Guaranteeing correct execution of tasks / problems to solve ● Quality Assurance ○ Quality assurance of all produced resources during development (ontologies, software, documentation)

30. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 30 Development Activities of the Ontology Design Process 1. Pre-Development 2. Development 3. Post-Development ● Environment Study ○ What is the designated software platform for the ontology? ○ Which applications should use the ontology? ● Feasibility Study ○ Can the ontology really be developed? ○ Does it make sense to develop the ontology? 1. Pre-Development Activities

31. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 31 Development Activities of the Ontology Design Process 2. Development Activities ● Specification ○ Why is the ontology developed, what is the benefit and who are the end-users? ● Implementation ○ Construction of a computable model in an ontology representation language ● Conceptualization ○ Structuring domain knowledge in a conceptual model ● Formalization ○ Formalize conceptual model in (semi-)computable model

32. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 32 Development Activities of the Ontology Design Process 3. Post-Development Activities ● Maintenance ○ Update and adjustment of the ontology (if necessary) ● Use / Re-Use ○ Usage of the ontology within the designated applications as well as in unplanned applications/ontologies?

33. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 33 Support Activities of the Ontology Design Process ● Knowledge Acquisition ○ Gather knowledge from experts (Ontology Learning) ● Evaluation ○ Technical evaluation of the ontology in each step of the development process ● Integration ○ Reuse of existing ontologies (Ontology Reuse) ● Merging ○ Construction of a new ontology from already existing ontologies within a specific domain

34. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 34 Support Activities of the Ontology Design Process ● Alignment ○ Design/apply mapping rules for involved ontologies ● Documentation ○ Each step of the ontology development must be accurately documented ● Configuration Management ○ Manages all versions of documentation and of the developed ontology

35. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 35 Ontology Design Methodologies “Though this be madness, yet there is method in it” William Shakespeare, Hamlet (1602)

36. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 36 ● in practice an iterative Process that repeats continuously and improves the ontology ● there are always different approaches for modelling an ontology ● in practice the designated application decides about the modelling approach Ontology Development 101 (Noy, McGuinness, 2000) „There is no one correct way to model a domain. There are always viable alternatives.“

37. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 37 Unified Process for Ontology Building De Nicola, Missikoff, Navigli (2005) ● Development is divided into Cycles, which are subdivided into 4 Phases of Iterations (Inception, Elaboration, Construction, Transition). Each iteration results in a new prototype ● Each iteration consists of 5 workflows (Requirements, Analysis, Design, Implementation, Test)

38. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 38 Ontology Design Patterns Gangemi (2005) ● Adapting a design idea originally from architecture ○ recurring modeling problems ○ providing a set of adaptable standard solutions ○ a “pattern” is a solution to a problem in a given context (Christopher Alexander) The elements of this language are entities called patterns. Each pattern describes a problem that occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice. — Christopher Alexander

39. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 39 Hans Holbein the Younger: The Ambassadors (1533) [15] “Reality is that which, when you stop believing in it, doesn't go away.” Philip K. Dick, How To Build A Universe That Doesn't Fall Apart Two Days Later (1978)

40. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 40 ● Ontologies are not the Reality ● Ontologies are a context-dependent projection (model) of the Reality ● Ontologies are engineering artefacts ● Ontologies are shared among different components for potentially different tasks ● Ontologies might be reused in unexpected ways ● Ontologies are used to integrate heterogeneous data sources Evaluation of Ontologies is necessary, but (might be) difficult... Hans Holbein the Younger: The Ambassadors (1533) [15]

41. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 41 ● Ontology Evaluation ○ can be defined as the process of deciding the quality of an ontology ● Ontology Verification: ○ checks the encoding of the specification ○ detects errors, as e.g. circular, class hierarchies, redundant axioms, inconsistent naming schemes etc. ○ confirms that the ontology has been built according to certain specified ontology quality criteria ● Ontology Validation: ○ checks whether the meaning of the definitions matches with the conceptualization the ontology is meant to specify ○ the goal is to show that the world model is compliant with the formal model Ontology Evaluation

42. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 42 Ontology Evaluation Real World Model (Approximate Conceptualization) Abstraction Generalization Aggregation ... Evaluation: Metrics, Methods, etc. Distance between Real World and Model acc. to Hlomani: Approaches, methods, metrics, measures and subjectivity in ontology evaluation, ACM 2014

43. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 43 Criteria for Ontology Evaluation (1/4) ● Accuracy: ○ Do axioms comply to the expertise of the users? ○ Does the ontology capture and represent correctly aspects of the real world? ● Adaptability: ○ Does the ontology offer the conceptual foundation for a range of anticipated tasks? ○ Can the ontology be extended and specialized monotonically, i.e. without the need to remove axioms? ○ Does the ontology comply to procedures for extension, integration, and adaption? D.Vrandecic: Ontology Evaluation, in Ontologies Handbook, 2nd ed, 2009

44. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 44 Criteria for Ontology Evaluation (2/4) D.Vrandecic: Ontology Evaluation, in Ontologies Handbook, 2nd ed, 2009 ● Clarity: ○ Does the ontology communicate effectively the intended meaning of the defined terms? ○ Are the definitions objective and independent of context? ○ Does the ontology use definitions or (partial) descriptions? ○ Are the definitions documented? ○ Is the ontology understandable? ● Completeness: ○ Is the domain of interest appropriately covered? ○ Are competency questions defined and can the ontology answer them? ○ Does the ontology include all relevant concepts and their lexical representations?

45. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 45 Criteria for Ontology Evaluation (3/4) D.Vrandecic: Ontology Evaluation, in Ontologies Handbook, 2nd ed, 2009 ● Computational Efficiency: ○ How easy and successful can reasoners process the ontology? ○ How fast can the standard reasoning processes (satisfiability, instance classification, etc.) be applied to the ontology? ● Conciseness: ○ Does the ontology include irrelevant axioms? ○ Does the ontology specify the weakest theory possible and define only essential terms? ○ How weak are the assumptions regarding the ontology’s underlying philosophical theory about reality?

46. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 46 Criteria for Ontology Evaluation (4/4) D.Vrandecic: Ontology Evaluation, in Ontologies Handbook, 2nd ed, 2009 ● Consistency: ○ Do the axioms lead to contradictions (logical consistency)? ○ Are formal and informal description of the ontology consistent? ○ Are any representation choices made purely for the convenience of notation or implementation? ○ Does the translation from the knowledge level to the encoding show a minimal encoding bias? ● Organisational Fitness: ○ Is the ontology easily deployed within the organization? ○ Do tools within the organization put constraints on the ontology? ○ Does the ontology meet legal requirements, etc.?

47. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 47 Measures for Ontology Evaluation ● Direct measurement of the mentioned criteria is difficult ● Ontology Correctness ○ Accuracy, e.g. via precision (total number correctly found over whole knowledge defined in ontology) and recall (total number correctly found over all knowledge that should be found) ○ Completeness, e.g. via coverage of encoded axioms and axioms in specification ○ Consistency, e.g. count terms with inconsistent meaning ● Ontology Quality ○ Computational Efficiency, e.g. via size ○ Adaptability, e.g. via coupling (number of external classes referenced) and cohesion (number of root, leaf, avg. inheritance depth, etc.) ○ Clarity, e.g. via number of word senses

48. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 48 OntoClean Guarino, Welty (2001) ● OntoClean for Ontology Validation ○ helps to expose common misuses of subsumption and ○ provides a formal basis for why they’re wrong ● OntoClean helps to expose ○ inappropriate and inconsistent modelling choices ○ implicit assumptions about the way in which the atomic properties or classes are being interpreted ○ ontological commitments being made by the modeller ● OntoClean focuses on taxonomy and subsumption: ○ A subsumes B iff for all x, x instance of B implies x instance of A

49. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 49 “Grau ist alle Theorie. Entscheidend is’ auf’m Platz.” Alfred ‘Adi’ Preißler, Borussia Dortmund (1956) Albrecht Dürer, Melancholia 1, 1514 [16]

50. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 50 The Renaissance of “Soft” AI Carol Kaelson/Jeopardy Productions Inc., via Associated Press Linked Data and Knowledge Graphs The Linked Data Cloud, 2019 [17]

51. Information Service Engineering , Prof. Dr. Harald Sack, FIZ Karlsruhe - Leibniz Institute for Information Infrastructure & AIFB - Karlsruhe Institute of Technology - #Lectures4FutureThe Semantic Web - Not just a piece of cake, [18]

52. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 52 Ontology Types and Categories according to their level of Generality Semantic Search & Retrieval Ontology & Knowledge Graph Applications 52 Text/Data Acquisition Index Creation Text/Data Transformation User Interaction Ranking Evaluation Retrieval Process Indexing Process IndexDocument Store Knowledge Graph Messy Store Room with Boxes, [19]

53. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 53 Ontology Types and Categories according to their level of Generality Semantic Search & Retrieval Ontology & Knowledge Graph Applications 53 TIB AV-Portal German National Library of Science and Technology > 10.000 videos OCR, ASR, VCD NEL GND http://av.tib.eu/ J. Waitelonis, M. Plank, H. Sack, TIB|AV-Portal: Integrating Automatically Generated Video Annotations into the Web, in Proc. of 20th International Conference on Theory and Practice of Digital Libraries (TPDL 2016), pp 429-433

54. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 54 Ontology Types and Categories according to their level of Generality Semantic Search & Retrieval Ontology & Knowledge Graph Applications 54 Document Text (Labels) Knowledge Graph (Instances) Ontology (Classes & Relations) Jörg Waitelonis, Claudia Exeler, and Harald Sack. Linked Data enabled Generalized Vector Space Model to improve document retrieval. In Proc. of NLP & DBpedia 2015 workshop in conjunction with 14th International Semantic Web Conference (ISWC2015), CEUR Workshop Proceedings, Vol1581, pp 33-44, 2015.

55. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 55 Ontology Types and Categories according to their level of Generality Semantic Annotation Support Ontology & Knowledge Graph Applications 55 e.g. via refer.cx WordPress PlugIn at http://scihi.org/ T. Tietz, J. Jäger, J. Waitelonis, H. Sack,S emantic Annotation and Information Visualization for Blogposts with refer, Proc. of 2nd. Int. Workshop on Visualization and Interaction for Ontologies and Linked Data 2016, co-located with ISWC 2016, Vol. 1704, pp. 28-40

56. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 56 Ontology Types and Categories according to their level of Generality Concept-Based Search Ontology & Knowledge Graph Applications 56 J. Osterhoff, J. Waitelonis, and H. Sack. Widen the Peepholes! Entity-Based Auto-Suggestion as a rich and yet immediate Starting Point for Exploratory Search. Proc. of 2. Workshop Interaktion und Visualisierung im Daten-Web IVDW 2012

57. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 57 Ontology Types and Categories according to their level of Generality Exploration & Recommendation Ontology & Knowledge Graph Applications 57 e.g. via refer.cx WordPress PlugIn at http://scihi.org/

58. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 58 “Technology presumes there's just one right way to do things and there never is” Robert M. Pirsig, Zen and the Art of Motorcycle Maintenance (1974) Camille Flammarion L'atmosphère: météorologie populaire (1888) [20]

59. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 59

60. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 60 Ontology Types and Categories according to their level of Generality 60 Collaborative Ontology Design for Materials Science https://vocol.iais.fraunhofer.de/

61. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 61 Ontology Types and Categories according to their level of Generality An Evolving Knowledge Graph For Materials Science 61

62. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 to be continued... Prof. Dr. Harald Sack What are Ontologies and why is one studying it? harald.sack@fiz-karlsruhe.de twitter: lysander07 Fraunhofer IWM Freiburg, 21. Oct. 2019 “As for me, all I know is that I know nothing..” Socrates, in Plato, Phædrus, Section CCXXXV (c. 370 BC)

63. Prof. Dr. Harald Sack: What are ontologies and why is one studying it?, Fraunhofer IWM Freiburg, Innovationsplattform MaterialDigital, 21. Oct 2019 Image References: [1] Erich Kuithan: Schiller auf dem Weg zu seiner Antrittsvorlesung, 1909/10, https://www4.uni-jena.de/Sonderausgabe_Schiller_Kuithans_Gemaelde.html [2] Matrix Computer Screen, https://pixabay.com/illustrations/matrix-code-computer-pc-data-356024/ [3] UBC Library Card Catalog, Paul Joseph, cc-by-2.0, https://commons.wikimedia.org/wiki/File:2009_3544505541_card_catalog.jpg [4] Tree of knowledge based on the French Encyclopedie from 1780, https://commons.wikimedia.org/wiki/File:Essai_d%27une_distribution_g%C3%A9n%C3%A9alogique_des_sciences_et_des_arts_principaux,_1780.jpg [5] Pieter Bruegel the ELder, The Tower of Babel, 1563, https://commons.wikimedia.org/wiki/File:Pieter_Bruegel_the_Elder_-_The_Tower_of_Babel_(Vienna)_-_Google_Art_Project_-_edited.jpg [6] Michelangelo Buonarotti, Creazione di Adamo, c. 1512, https://en.wikipedia.org/wiki/The_Creation_of_Adam#/media/File:Michelangelo_-_Creation_of_Adam_(cropped).jpg [7] Niklas Jansson, Touched by His Noodly Appendage, https://commons.wikimedia.org/wiki/File:Touched_by_His_Noodly_Appendage_HD.jpg [8] Arbor porphyrii, in translation of Boetius, 6th century, https://en.m.wikipedia.org/wiki/File:Arbor_porphyrii_(probably_from_one_of_Boethius%27_translations).png [9] Scientist (Ice Cream) 1986; Cover illustration for The New Yorker, August 4, 1986; Courtesy of Roz Chast and Danese/Corey, New York, https://www.nrm.org/2015/03/roz-chast-cartoon-memoirs/ [10] Hannah Wolley, The Queen-like Closet. 1672, <link> [11] Jorge Luis Borges by Annemarie Heinrich, 1967, https://commons.wikimedia.org/wiki/File:Jorge_Luis_Borges_by_Annemarie_Heinrich,_1967.jpg [12] A fantasy map of a flat earth. Photograph: Antar Dayal/Getty Images/Illustration Works <link> [13] The Software Deveopment Process, Geek & Poke, http://geekandpoke.typepad.com/geekandpoke/2012/01/simply-explained-dp.html [14] Liberty Statue, work in progress, 1884, https://commons.wikimedia.org/wiki/File:Statue_de_la_Libert%C3%A9,_en_construction.jpg [15] Hans Holbein the Younger, The Ambassadors, 1533, https://commons.wikimedia.org/wiki/File:Hans_Holbein_the_Younger_-_The_Ambassadors_-_Google_Art_Project.jpg [16] Albrecht Dürer, Melancholia 1, 1514, https://commons.wikimedia.org/wiki/File:D%C3%BCrer_Melancholia_I.jpg [17] The Linked Data Cloud, 2019, https://lod-cloud.net ] [18] The Semantic Web, Not just a piece of cake, http://bnode.org/blog/2009/07/08/the-semantic-web-not-a-piece-of-cake [19] Messy Storage Room with Boxes, https://commons.wikimedia.org/wiki/File:Messy_storage_room_with_boxes.jpg [20] Camille Flammarion L'atmosphère: météorologie populaire (1888), https://en.wikipedia.org/wiki/File:Flammarion.jpg