1. 02. November 2007 Florian Probst Data and Knowledge Modelling for the Geosciences - Chris Date Seminar - e-Science Institute, Edinburgh Semantic Reference Spaces for Observations and Measurements

2. Florian Probst 2... short version Theory on how to categorize Qualities („properties of things“) and how to name their magnitudes („property values“) --> Ontologies --> Semantics

3. Florian Probst 3 Vision, Motivation, Problem (Where to go? Why? What‘s the problem?) Background (Semantics, Ontologies ) Research Questions Assumptions (basis of the approach) Qualities and Quality Spaces (ontological part) Semantic Reference Spaces (semantic part) Unit of Measure Region Extension Quality Roles Summary and Future Work

4. Florian Probst 4 Vision, Motivation and Problem Vision: Answer questions (solve problems) based on information from distributed and heterogeneous information sources. --> knowledge infrastructure, e-science Motivation: Sharing knowledge requires the ability to compare conceptualizations and the ability to communicate about the meaning of words. Problem: Lack of methods to assess semantic interoperability of information sources. ? Gewässer max. Tiefe in Meter #A30 #B52 lakedepth in inch #10.11 #20.23

5. Florian Probst 5 Ontology  An ontology is a symbol system (= human made artifact)  An IS ontology is a formal theory. Information System Ontologies ”An ontology is a formal and explicit partial account of a conceptualization.” (Guarino, 1998) Conceptualization “world view” Referent

6. Florian Probst 6 Focus What are the basic building blocks of geospatial information?  results of observations and measurements. Focus on: unary qualities of physical entities Examples: the height of a mountain the mass of an apple the volume of a lake

7. Florian Probst 7 Goal and Research Questions If we want to communicate the meaning of words denoting observations results we need to answer: What is the ontological nature of an observation? How to explicate the conceptualization underlying an observation result? How to name an observation result? --> Develop methods to identify commensurability of information sources.

8. Florian Probst 8 Assumptions "Stand alone ontologies" are not enough for comparing conceptualizations. commensurable  A foundational ontology is required My work is based on DOLCE (www.loa-cnr.it/)

9. Florian Probst 9 measuring = approximating perceiving = approximating Endurants, Qualities and Magnitudes Volume Quality Space volume quality (understood as individual entity) physical endurant volume quality hasQuality physical endurant hasQuality Magnitudes of qualities are structured in quality spaces. 10 cm 3 Reference Space hasQualityLocation

10. Florian Probst 10 Taxonomy of Quality Spaces

11. Florian Probst 11 Quality Spaces and Reference Spaces How to associate a sign with a magnitude?

12. Florian Probst 12 Elements of a Semantic Datum I

13. Florian Probst 13 Roles Roles are individual entities An entity can play roles. An entity does not loose its identity when it stops playing a certain role. --> any-rigid or non-essential A role allows to functionally characterize an entity Ontology engineering problem: At a certain stage anything seems to be a role.

14. Florian Probst 14 Position of the Grounding Region

15. Florian Probst 15 Elements of a Semantic Datum II Grounding Magnitude A grounding magnitude is defined by agreement of a community. An atomic quality region plays the role of a grounding magnitude. Grounding Reference Region Since a unit of measure maps to an atomic quality region, practically useful measurement is not yet possible. The grounding reference region extends the number of magnitudes that can be validly named from a single magnitude to a magnitude range. It is this extension that makes measurement possible. Region Extension Quality This kind of quality specifies the extent of the each non-atomic reference region in the reference space. Unit of Measure The previously agreed grounding magnitude grounds an atomic reference region. Sign for the Unit of Measure Any symbol can be used to denote the unit of measure, e.g. /1mm/. Note that the grounding magnitude gives meaning to this symbol. Position of the Unit of Measure within the Grounding Region Without an explicitly defined position of the unit of measure within the grounding region, the grounding region can map on different magnitude ranges

16. Florian Probst 16 Results The presented theory provides answers on how to classify observable entities how to structure the magnitudes of qualities in a scientific as well as cognitive plausible way how to partition the structured magnitudes and how to name the partitions. + Ontology for qualities, endurants and perdurants + Ontology for quality spaces + Semantic Reference Spaces Theory of semantic reference systems for observations and measurements

17. Florian Probst 17 Future Work Formal Ontology Extend theory: Investigate relational qualities (relational moments) and roles. Usability Methods for supporting users in “learning” a formal ontology. Research idea: semantic annotation infrastructure Semantic Translation Research idea: Combine methods for semantic similarity measurement with semantic reference systems.

18. Florian Probst 18 Thanks for your attention!