“'POLYGNOSIS'': Educational Knowledge Web Platform and
semantically linked Thesaurus on optical and laser-based
techniques for Cultural Heritage analysis and diagnosis”
N. Platia1, M. Chatzidakis1, K. Doerr2, L. Harami2, Ch. Bekiari2, K. Melessanaki3, K. Hatzigiannakis3, P. Pouli3
Department of Conservation of Antiquity and Works of Art, Technological Educational Institute (T.E.I.) of Athens1,
Centre for Cultural Informatics (CCI), Information Systems Laboratory (ISL), Institute of Computer Science (ICS), Foundation for Research
and Technology-Hellas (FORTH) 2 and Photonics for Cultural Heritage Laboratory, Institute of Electronic Structure and Lasers (IESL),
Foundation for Research and Technology-Hellas (FORTH) 3
INTRODUCTION
‘POLYGNOSIS’ ELECTRONIC HANDBOOK
‘’POLYGNOSIS’’ is an educational, Web-Based
Information System (WBIS) with emphasis on the
conservation, analysis and diagnosis of Cultural Heritage
(CH) objects with the use of laser-based and optical
methods. It includes notions of conservation of works-ofart, as well as, the examination and analysis method
applications on CH objects. The purpose of the system is to
assist primarily art conservators, but also scientists who
apply such scientific investigation methods.
The present study involves the collection and
curation of data for the enrichment of the Knowledge
Platform, as well as, the definition and classification of
terms for the semantically linked Thesaurus. It includes the
organization and analysis of knowledge acquired by
examination procedures and scientific texts (research
articles, instructional manuals for the use of the
instruments, analysis reports etc.).
The aim of the system is to be a reference and
educational tool for the analytical and diagnostic laser
technologies, and also, provide a powerful conduit for
research and study of CH materials, condition state and
pathology.
Description of User Interface
The Best Practice Guide is the core of the
POLYGNOSIS's website, where accumulated knowledge
regarding the selection of the diagnostic tool and the
suggested
methodology
are
presented,
with
simultaneous display of examples of actual method
applications on CH objects.
The model relates those examples to the relevant
terminology of the thesaurus (Glossary), the
information about the object under examination
(Objects) and the data extracted and processed from
those procedures (Data). Most of the current semantic
connections consist of simple hyperlinks between
information pages.
Each top-level content category is considered an
alternative study suggestion for better understanding
the use of the investigation methods presented. The
current system aims to introduce the methods of
Multispectral Imaging, Digital Holographic Speckle
Pattern Interferometry (DHSPI), Raman Spectroscopy
and Laser Induced Breakdown Spectroscopy (LIBS).
SEMANTICALLY-LINKED THESAURUS
METHOD APPLICATION
In ‘POLYGNOSIS’ knowledge is produced
through analysing and assessing the available
material. The user selects an investigation method
that provides evidence for certain kinds of
phenomena or features of objects, while the
system describes the actual process and
methodology that produced this evidence, by
displaying examples of best practice. Each
example is based on an actual examination of an
object and is documented by informative texts and
images.
‘Polygnosis’ Case Study
‘’POLYGNOSIS’’ thesaurus is a semantically structured
vocabulary organized by a faceted classification, which provides a
global subdivision of concepts through Broader-Narrower Term
Hierarchy.
It is designed under four extensible facets:
a. “Material Objects”: dealing with the investigated CH objects
b. “Investigation Methods”: dealing with optical and laser-based
techniques,
c. “Identifiable Features”: dealing with the detectable evidences
d. “Data”: dealing with the results of the investigation
procedures and their diagnostic and documentation material.
Methodology followed for the construction
of the thesaurus:
1. Collection and study of sources and
relevant documents
2. Semantic categories and facets of the
thesauri
3. Hierarchy building and formation of
relationships between terms (hierarchical,
associative and equivalence relationships)
Detail of a mural painting studied by Multispectral
Imaging; the aim was to study, map and
differentiate red pigments located in 4 spots of
the painting, representing different historical eras.
450nm
Map of the
analysed spots
on the mural
painting
Reflectance
spectra of all
four spots
analysed
600nm
450nm
600nm
Facets are mapped to CIDOC Conceptual Reference
Model (ISO 21127) entities:
•‘Material Objects’ maps to E70 Thing,
•‘Investigation Methods’ maps to E29 Design or
Procedure,
•‘Identifiable Features’ maps to E26 Physical
Feature
•‘Data’ maps to E73 Information Object.
Conclusions & further research
‘‘Polygnosis’’ provides reliable access to highly specialized knowledge. Its contents are dynamically
enriched and semantically organized. It implements a comprehensive environment with respect to a
problem. The system gives access to specialized information and guides users to identify categorical
relationships through real examples -crucial for interpreting the complex and constantly evolving
methodologies and tools described. It classifies examples of examination and diagnosis (“assessment”),
texts, object descriptions, images, data produced by the applied methods to specific objects.
Moreover, the thesaurus’ faceted classification brings to light hidden connections between the terms
and establishes concept relationships. Thus, each term acts as a junction and offers a holistic point of
view for understanding a large part of the knowledge area. To conclude, future work may include the
development of mechanisms that would enable the adaptive representation of the system’s content
according to learners’ profiles and educational needs, as well as, allow the exchange of users’
assessments, opinions and ideas through an experts’ forum.
Bibliography
•M.Doerr, (2004), Modeling Learning Subjects as Relationships, Human Interface 2004, LNAI 3359, pp. 201.214
•N. Crofts, M. Doerr, T. Gill, S. Stead, M. Stiff, Definition of the CIDOC Conceptual Reference Model, ISO (2005)
•ANSI/NISO Z39.19 (2010) “Guidelines for the construction, format and management of monolingual thesauri”, National Information Standards Organization (NISO), NISO Press, Bethesda, Md.
•V. M. Papadakis, Y. Orphanos, S. Kogou, K. Melessanaki, P. Pouli, C. Fotakis (2011), IRIS: a novel spectral imaging system for the analysis of cultural heritage objects, SPIE, Volume 8084, pp.1-6
•ISO 2788 (1986) “Documentation – Guidelines for the establishment and development of monolingual thesauri”, 2nd ed., International Organization for Standardization
Acknowledgments
This study was financed by the research project “POLITEIA”, Action KRIPIS,
project No MIS-448300 (2013SE01380035) that was funded by the Ministry
of Culture and the General Secretariat for Research and Technology, Ministry
of Education, respectively, in Greece and the European Regional
Development Fund (Sectoral Operational Programme: Competitiveness and
Entrepreneurship, NSRF 2007-2013)/ EC.