1. ICS-FORTH Which Period Is It? A Methodology To Create Thesauri Of Historical Periods Martin Doerr, Athina Kritsotaki, Stephen Stead

2. ICS-FORTH2 What does “Period” mean? Period definition by CIDOC CRM (ISO/CD21127): “ This class comprises sets of coherent phenomena or cultural manifestations bounded in time and space. It is the social or physical coherence of these phenomena that identify an E4 Period and not the associated spatio-temporal bounds. These bounds are a mere approximation of the actual process of growth, spread and retreat. Consequently, different periods can overlap and coexist in time and space, such as when a nomadic culture exists in the same area as a sedentary culture. … “ “ This class comprises sets of coherent phenomena or cultural manifestations bounded in time and space. It is the social or physical coherence of these phenomena that identify an E4 Period and not the associated spatio-temporal bounds. These bounds are a mere approximation of the actual process of growth, spread and retreat. Consequently, different periods can overlap and coexist in time and space, such as when a nomadic culture exists in the same area as a sedentary culture. … “

3. ICS-FORTH3 Problem  Vagueness of traditional definition  Confusion of evidence and conclusion, definition and interpretation  Confusion of general characteristics and distinct characteristics  Confusion of definition and spatiotemporal approximation  Lack of communication – different scientists use different definitions and different terminology

4. ICS-FORTH4 Objectives  Develop a method and a standard template to describe period definitions (as found in literature) in a formal and comprehensive way (NOT to research periods)  Construction of a thesaurus capturing formal relations This enables us to: - Standardize forms and templates - Standardize forms and templates - Organize archaeological information in a computerized environment - Organize archaeological information in a computerized environment - Classify museum objects consistently by true period of creation - Classify museum objects consistently by true period of creation - Identify contemporary finds in archaeological research and excavations - Identify contemporary finds in archaeological research and excavations - Make easier the communication and knowledge sharing between scientists - Make easier the communication and knowledge sharing between scientists

5. ICS-FORTH5 The presented method and thesaurus does not aim to analyze periods or to prescribe a correct scientific opinion about chronological problems! Instead, it aims to provide via a methodical approach:  an overview of scientific opinions  the relationships between multiple period definitions

6. ICS-FORTH6 Approach  A Schema specification in the form of an XML DTD for: - data acquisition - data exchange  An example (of period names within the Helladic period) as a proof of concept  Implementation in a knowledge base

7. ICS-FORTH7 DTD Major Elements - metadata about the conception of the period and multilingual terminology naming the period - definition (defining criteria & events) - spatiotemporal extent, evolution and spatiotemporal relationships - characteristic attributes and cultural influences - metadata about the documentation

8. ICS-FORTH8 Definition of period Period is defined by distinct (“defining”) criteria based on the archaeological contexts rather than by time and place. “Defining criteria” are: types of phenomena or interrelated phenomena that determine the unity and identify the cultural continuity of a period. “Defining criteria” are distinguished from the “general characteristics” that simply describe periods and may be distinct or not.

9. ICS-FORTH9 Period definition: DTD

10. ICS-FORTH10 Period definition and events Events are related to period definition.They may mark limits of the temporal extent of a period. Events may happen at the beginning or at the end of a period, but they don’t cause a period. They are seen as occasion rather than cause. Those events do not define the periods themselves as cultural phenomena.

11. ICS-FORTH11 Spatiotemporal extent The extent of a period (in time and space) is approximated by a description of spatial and temporal outer bounds. The extent of a period (in time and space) is approximated by a description of spatial and temporal outer bounds. The extent of a period can be described as a temporal evolution over space. The extent of a period can be described as a temporal evolution over space. The spatiotemporal extent is also constraint by The spatiotemporal extent is also constraint byspatial temporal, and spatiotemporal relations resulting from archaeological evidence (not absolute dating) resulting from archaeological evidence (not absolute dating)

12. ICS-FORTH12 Spatiotemporal extent: DTD

13. ICS-FORTH13 Characteristics attributes: DTD

14. ICS-FORTH14 An example: (XML-XSL)

15. ICS-FORTH15 Conclusions  A formal methodology has been developed to capture period definition and description, based on CIDOC specifications, archaeological reasoning and computer science.  A schema, in the form of XML DTD, has been defined to structure terms and relations of a Period Thesaurus.  A multilingual thesaurus of period definitions within the Helladic period is under development.