Data Objects & Semantics

Transcription

1 ITN-DCH Summer School Martin Doerr Center for Cultural Informatics, Institute of Computer Science Foundation for Research and Technology - Hellas Stuttgart, Germany, October 22, 2014 IFORTH-ICS October 2014 Cultural Research: What, Who, How Disciplinary processes related to cultural heritage: Evidence collection: Observing and surveying (walking & seeing, satellite, seismic, radar ) Excavating, collecting (field, market, bequeathal, donation etc.) Imaging (drawing, painting, digitization, 2D/3D surface, density, video) Analytical examination (chemical, radiological, structural (optical, X-ray) Finding historical sources.and recording events, finds, findings and used methods Collection documentation: maintaining Inventory books & collection management systems Library catalogues Archival find books Monument records 2

2 Disciplinary processes related to cultural heritage cont d: Preservation: Administration (control of access and use, protection) Conservation (planning and intervention) Researching (science and scholarship) : Investigation, aggregation, interpretation of evidence Aggregation and interpretation of interpretation Dissemination Presentation - exhibition, site access, performing, story telling (things in context, how it could have been) Teaching Cultural Research: What, Who, How Publication (scholarly, general public, movie, Web) 3 Relevance of Cultural Objects 4

3 Relevance of Cultural Objects By: Thomas Bewick , London In: The figures of Bewick s quadrupeds, Edward Walker, Newcastle, Relevance of Cultural Objects Individual value: Artistic, stylistic significance Social, spiritual, symbolic utility and value usually expensive and impressive Illustrating a context: Presence at a historical event, property of a person (use?, why?) Historical impact in art, technology, social history Use as scientific evidence, such as chronology of an excavation layer worthless without knowing 6

4 Illustrating a kind: Rarity or representativeness Value of the kind as such: functional (utility/aesthetic) significance, historical impact, scientific evidence Value of the kind of illustrated context: Ecosystems, traditions and customs of social groups, communities and nations If not rare, easy to replace Potential: Relevance of Cultural Objects Research potential to reveal historical or scientific facts or to support interpretation Potential future use 7 Due to differences in research subjects and disciplines, there is no core description of cultural heritage. Despite disciplinary differences, all knowledge is related and mutually relevant. We propose: Meaning and services Whatever we regard as semantic or meaning in ITN_DCH should be related in a clear way to the terms of relevance presented above. Whatever IT services we provide, should play a clearly identifiable functional role in the respective processes. 8

5 What are Metadata Metadata: Data about Data, abused for data about things, confused with any data about individual activities Metadata are information containers, not to be detached from the content or object, and not from their source of knowledge. A notion of what is necessary to be documented about a (content) object at time of acquisition or ingest! In OAIS, Preservation Description Information (PDI) are the metadata that contains information that will allow the understanding of the Content Information over an indefinite period of time. (OAIS PDI types (functional specs!): Reference Information, Provenance Information, Context Information, Fixity Information) 9 Example: Mobile Object Record One document (the metadata ) per object 10

6 Small museum administration 11 12

7 Knowledge management has 3 levels: Knowledge Management Acquisition needs: (your database (metadata), can be derived from ontology) sequence and order, completeness, constraints to guide and control data entry. ergonomic, case-specific language, optimized to specialist needs often working on series of analogous items interoperability needs capability of your database to be mapped! Integration / comprehension needs: (target of the global ontology): break up document boundaries, relate facts to wider context match shared identifiers of items, aggregate alternatives explore contexts, no preference direction of search, no cardinality constraints interoperability needs a global schema Reasoning, presentation, story-telling needs: (can be based on the ontology) represent contexts orthogonal to data acquisition present in order, allow for digestion support deduction and induction What Form of Integration Schema? Data integration in the mid 90 s has shown: impossible to integrate RDBMS under RDBMS Equally impossible are the application profiles! First Cause: No generalization of properties (attributes, fields). Second cause: Optimizing data entry forms semantics causes heterogeneity. Problem to solve: integrate specialized and generalized databases Knowledge representation, such as RDF/OWL can generalize over tables AND fields Simple idea: Break data up into independent propositions (using URIs!), boxes and arrows describe facts by broader/narrower categories and broader/narrower relationships! This is knowledge representation. 14

8 The Scholarly Process Hypertext is wrong! Refer interpret present Publications Stories exhibitions Search, correlate, integrate Donald Johanson Cleveland Museum of Natural History Johanson's Expedition Ethiopia Hadar Discovery of Lucy Lucy AL Layer of Latest Knowledge discover collect aggregate update Evidence layer Things Sources Collections Corpora 15 Knowledge Representation: Basic Notions What is Knowledge Representation : Representation of concepts, items (particulars) and their interrelation as perceived by humans and expressed in terms of a formal language, such as logic, conceptual graphs etc. The intended meaning (semantics) is the interpretation (identification) of used symbols as things and categories in the described universe ( domain, world, real world), and the interpretation of expressions with those symbols as statements about their structure and interrelations (early Wittgenstein). A set of related knowledge representation expressions is called a model (of a domain). Only humans know the interpretation function. This turns information into knowledge. Knowledge cannot be stored!! IT Jargon: KNOWLEDGE for model, SEMANTICS for logical expressions 16

9 Limitations: Knowledge Representation: Reservations Principle of equivalence ( Turing Test ): Given a model accepted as correct by a human, logical (automatable) inferences from a model should conform with the expectations of a human. Only in this sense represents knowledge representation (KR) knowledge. KR is a means of communication. Logical expressions are rarely definitions, but partial constraints. (see also late Wittgenstein, Eleonore Rosch - George Lakoff). Formal languages fit only partially the way we think. Psychological Obstacles to create KR: The true structure of our thoughts is unconscious. Methodological questions reveal part of the unconscious (e.g. change of context). 17 From Forms to Classes (a decompression ) Relational Database Tables: - an abstraction from forms, - a model for (statistical) information processing Table name Patient Name String Attributes (sometimes called part-of ) Weight Birth date Birth Place Number Time String Value types Address String What does that mean as statements about the world? Is it correct, e.g., Address? 18

10 Knowledge Representation:From Forms to Classes Name Patient String has has has has Shared Context specific Independent entity Who is the Patient then? 1 1 Patient s Weight Birth Date Time Place String Address 19 Knowledge Representation: Classes and Instances In KR, instances are independent units of models, not a restricted to the records of one table. Identity is separated from description. We can do multiple instantiation.? Weight Doctor Patient Address Costas 65 George 1 Odos Evans 6. GR71500 Heraklion, Crete, Greece 85 Kg What have doctors and patients in common? instance property 20

11 Generalization and Inheritance An instance of a class is an instance of all its superclasses. A subclass inherits the properties of all superclasses. (properties move up ) weighs superclass Physical Object Weight Person dwells at Address isa subclass Doctor Patient Costas 65 George 1 Odos Evans 6. GR71500 Heraklion, Crete, Greece 85 Kg 21 Ontology and Information Systems An ontology is a logical theory accounting for the intended meaning of a formal vocabulary, i.e. its ontological commitment to a particular conceptualization of the world. It can only approximate the models intended by the expert. (Nicola Guarino, Formal Ontology and Information Systems, 1998) Ontologies are models of possible states of affairs. Ontologies pertains to a perceived truth: A conceptualization typically of a group, how we imagine things in the world are related. An ontology can be implemented on a database with compromises(!!) on datatypes and identifiers, e.g., with RDF, OWL. Then it becomes an information system which is (hopefully!) consistent with our knowledge. 22

12 Terminology and Information Systems We define as terminology (vocabulary) as a system of named universals (classes) which is used in an information system as data, i.e., their use does not depend or imply instance relationships that hold only between these the terms or their specializations. e.g., has_type : car, has_type : wheel is not used to say in which position of this car this wheel is mounted. Terminological systems are organized in KOS, typically with specialization/generalization hierarchies, and categorical relations (such as: cars have parts wheels) For us (FORTH-ISL, CRM-SIG), terminological systems are NOT ontologies! Gazetteers and Person lists are NEVER ontologies, they describe particular states of affairs. 23 Historical Archives Type: Text Title: Protocol of Proceedings of Crimea Conference Title.Subtitle: II. Declaration of Liberated Europe Date: February 11, 1945 Creator: The Premier of the Union of Soviet Socialist Republics The Prime Minister of the United Kingdom The President of the United States of America Publisher: State Department Subject: Postwar division of Europe and Japan Metadata About Documents The following declaration has been approved: The Premier of the Union of Soviet Socialist Republics, the Prime Minister of the United Kingdom and the President of the United States of America have consulted with each other in the common interests of the people of their countries and those of liberated Europe. They jointly declare their mutual agreement to concert.and to ensure that Germany will never again be able to disturb the peace of the world 24

13 Images, non-verbose Type: Image Title: Allied Leaders at Yalta Date: 1945 Publisher: United Press International (UPI) Source: The Bettmann Archive Copyright: Corbis References: Churchill, Roosevelt, Stalin Photos, Persons Metadata About 25 Explicit Events, Object Identity, Symmetry E39 Actor E52 Time-Span February 1945 P82 at some time within E7 Activity E53 Place E39 Actor Crimea Conference E38 Image P86 falls within E39 Actor E65 Creation Event * P81 ongoing throughout E52 Time-Span E31 Document Yalta Agreement 26

14 Outcomes The CIDOC Conceptual Reference Model A collaboration with the International Council of Museums An ontology of 90 classes and 150 properties for culture and more With the capacity to explain hundreds of (meta)data formats Accepted by ISO TC46 in September 2000 International standard since ISO 21127:2006 To be revised in 2014 (minor extensions) Serving as: intellectual guide to create schemata, formats, profiles A language for analysis of existing sources for integration/ mediation Identify elements with common meaning Transportation format for data integration / migration / Internet 27 Data example (RDF-like form) Epitaphios GE34604 (entity E22 Man-Made Object) P30 custody transferred through, P24 changed ownership through Transfer of Epitaphios GE34604 (entity E10 Transfer of Custody, E8 Acquisition Event) P28 custody surrendered by Metropolitan Church of the Greek Community of Ankara (entity E39 Actor) P23 transferred title from Metropolitan Church of the Greek Community of Ankara (entity E39 Actor) P29 custody received by Museum Benaki (entity E39 Actor) P22 transferred title to Exchangeable Fund of Refugees (entity E40 Legal Body) P2 has type national foundation (entity E55 Type) P14 carried out by Exchangeable Fund of Refugees (entity E39 Actor) P4 has time-span P7 took place at Greece GE34604_transfer_time (entity E52 Time-Span) P82 at some time within (entity E61 Time Primitive) (entity E53 Place) P2 has type nation (entity E55 Type) republic (entity E55 Type) P89 falls within Europe (entity E53 Place) P2 has type continent (entity E55 Type) Multiple Instantiation TGN data 28

15 Top-level classes useful for integration E55 Types refer to / refine E39 Actors participate in affect or / refer to E28 Conceptual Objects E18 Physical Thing E2 Temporal Entities location E52 Time-Spans at E53 Places 29 The types of relationships Identification of real world items by real world names Observation and Classification of real world items Part-decomposition and structural properties of Conceptual & Physical Objects, Periods, Actors, Places and Times Participation of persistent items in temporal entities creates a notion of history: world-lines meeting in space-time Location of periods in space-time and physical objects in space Influence of objects on activities and products and vice-versa Reference of information objects to any real-world item 30

16 The E2 Temporal Entity Hierarchy E68 Dissolution E64 End of Existence E69 Death E6 Destruction E81 Transformation E67 Birth E4 Period E5 Event E63 Beginning of Existence E66 Formation E65 Creation E12 Production E2 Temporal Entity E3 Condition State E11 Modification E9 Move E83 Type Creation E80 Part Removal E 79 Part Addition E10 Transfer of Custody E8 Acquisition E17 Type Assignment E7 Activity E87 Curation Activity E14 Condition Assessment Generalization E13 Attribute Assignment E86 Leaving E15 Identifier Assignment E16 Measurement E85 Joining 31 Temporal Entity-Main Properties E2 Temporal Entity Properties: P4 has time-span (is time-span of): E52 Time-Span E4 Period Properties: P7 took place at (witnessed): E53 Place P9 consists of (forms part of): E4 Period P10 falls within (contains): E4 Period E5 Event Properties: P12 occurred in the presence of (was present at): E77 Persistent Item P11 had participant (participated in): E39 Actor E7 Activity Properties: P14 carried out by (performed): E39 Actor P20 had specific purpose (was purpose of): E5 Event P21 had general purpose (was purpose of): E55 Type P16 used specific object (was used for): E70 Thing P125 used object of type (was type of object used in) E55 Type 32

17 The Participation Properties The Real Difference! P16 used specific object (was used for) P25 moved (moved by) P11 had participant (participated in) P33 used specific technique (was used by) P142 used constituent (was used in) P146 separated from (lost member by) P96 by mother (gave birth) P14 carried out by (performed) P143 joined (was joined by) P145 separated (left by) P144 joined with (gained member by) P29 custody received by (received custody through) P22 transferred title to (acquired title through) P23 transferred title from (surrendered title through) P28 custody surrendered by (surrendered custody through) P12 occurred in the presence of (was present at) P93 took out of existence (was taken out of existence by) P31 has modified (was modified by) P99 dissolved (was dissolved by) P13 destroyed (was destroyed by) P124 transformed (was transformed by) P100 was death of (died in) P112 diminished (was diminished by) P110 augmented (was augmented by) P108 has produced (was produced by) P123 resulted in (resulted from) Generalization P92 brought into existence (was brought into existence by) P95 has formed (was formed by) P98 brought into life (was born) P94 has created (was created by) P135 created type (was created by) 33 t Historical Events as Meetings Brutus was present at! Caesar s mother was present at! Caesar was present at! was present at! was present at! Brutus dagger coherence volume of Caesar s death coherence volume of Caesar s birth? Forum Romanum, Rome 34 S

18 t 3D Model Creation as Meetings coherence volume of rendering 3D model coherence volume of mesh-creation scanner mesh-data 2 nd Computer museum object scan-data operator 1 st Computer coherence volume of acquisition Museum It-Lab S 35 Activities: E16 Measurement P140 assigned attribute to E1 CRM Entity (was attribute by) E13 Attribute Assignment P141 assigned (was assigned by) E1 CRM Entity E70 Thing P39 measured (was measured by) 1,1 E16 Measurement P40 observed dimension 1,n (was observed in) E54 Dimension 1,1 1,1 1,1 property Generalization Indirect Generalization P43 has dimension (is dimension of) Shortcut P91 has unit (is unit of) E58 Measurement Unit P90 has value E60 Number 36

19 P89 falls within (contains) E44 Place Appellation Properties of E53 Place P88 consists of (forms part of) E53 Place P87 is identified by (identifies) 0,1 P26 moved to (was destination of) P27 moved from (was origin of) 1,n 1,n P7 took place at (witnessed) E9 Move 1,n P25 moved (moved by) 1,n E4 Period E12 Production 1,n P108 has produced (was pro duced by) 1,1 P58 has section definition E46 Section Definition (defines section) E47 Spatial Coordinates E48 Place Name E45 Address Where was Lord Nelson s ring when he died? 1,n E18 Physical Thing 1,1 E24 Physical Man-Made Thing E19 Physical Object P8 took place on or within (witnessed) 37 Metadata and Global Ontology Ontology + specialization Metadata formats application dependent RDFS Subset Specialization Data structure with well defined mapping/transform 38

20 Object Metadata The data elements of a metadata document have an ontological view (propositions about reality the things under investigation useful for information integration ) Describe historical relevance and deal with the relationships of things, people, events, time and place, such as production, use, ownership. have an epistemological nature (statements of what has been understood statements how the knowledge was acquired - useful for understanding why we believe it) Describe observation (find), measurement, inference and reference processes. 39 Metadata, Ontologies and Research Epistemological considerations: Material facts: history as meetings of people, things and information. Material facts are supporting the discourse about possible pasts. Material facts are the most objective information we have. Material facts are carriers, evidence and constraints of the more vague and subjective social/intellectual processes and their interpretations we do not model! Metadata describe material facts. A global ontology allows for integrating them into a latest stage of knowledge. Research can then reason about the not observed or not observable. 40

21 Proposed Epistemological Core Model of Sciences Inductive reasoning Categorical Models (terminologies) Collective world view Deductive reasoning Possible Worlds and mechanisms of evolution Cognition models Innate or explicit Statistical reasoning Collective material behavior Material world (CRM) Factual world inferred Collective psychological behavior Socio -Psychological world Deductive reasoning Actual world in data or mind recognition Observable world Non discrete unlimited and unclassified material phenomena Reality Reasoning are also real world activities (CRM)!! 41