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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Modelling vagueness - A criteria-based system for the qualitative assessment of reading proposals for the deciphering of Classic Mayan hieroglyphs</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Franziska Diehr</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Sven Gronemeyer</string-name>
          <email>sgronemeyer@uni-bonn.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Elisabeth Wagner</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Christian Prager</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Katja Diederichs</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Uwe Sikora</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Maximilian Brodhun</string-name>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Nikolai Grube</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Department for Anthropology of the Americas, University of Bonn</institution>
          ,
          <country country="DE">Germany</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Department of Archaeology and History, La Trobe University</institution>
          ,
          <country country="AU">Australia</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>State and University Library Göttingen</institution>
          ,
          <country country="DE">Germany</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2018</year>
      </pub-date>
      <fpage>33</fpage>
      <lpage>44</lpage>
      <abstract>
        <p>The project 'Text Database and Dictionary of Classic Mayan' aims at creating a machine-readable corpus of all Maya texts and compiling a dictionary on this basis. The characteristics of this complex writing system pose particular challenges to research, resulting in contradictory and ambiguous deciphering hypotheses. In this paper, we present a system for the qualitative evaluation of reading proposals that is integrated into a digital Sign Catalogue for Mayan hieroglyphs, establishing a novel concept for sign systematisation and classification. The paper focuses in particular on the modelling process and thus emphasises the role of knowledge representation in digital humanities research.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Modelling vagueness in the Maya</title>
    </sec>
    <sec id="sec-2">
      <title>Dictionary project</title>
      <p>
        The not yet completely deciphered script of the
preColumbian Maya culture is the research subject
of the interdisciplinary project ‘Text Database and
Dictionary of Classic Mayan’.1 The aim of this
long-term project is to record the approximately
10,000 known text carriers and their inscriptions
in a machine-readable corpus and based on this
to compile a dictionary, which reflects the entire
vocabulary and its use in context
        <xref ref-type="bibr" rid="ref24">(Prager, 2014b)</xref>
        .2
As a joint effort, the specially established project
1. http://mayadictionary.de
2. The project started in 2014 and is expected to end in 2028.
It is funded by the North Rhine-Westphalian Academy of
Sciences and Arts http://www.awk.nrw.de and the Union
of German Academies of Sciences and Humanities https:
//www.akademienunion.de.
office, located at the Department for the
Anthropology of the Americas, University of Bonn,3 works
in close collaboration with the State and University
Library Göttingen.4 Since 2014, the hieroglyphic
texts have been prepared, evaluated, and interpreted
in interdisciplinary cooperation using methods and
tools from the humanities and information
technology
        <xref ref-type="bibr" rid="ref24">(Prager, 2014c)</xref>
        .
      </p>
      <p>One result of this collaboration, and at the same
time an important milestone of the project, is the
digital Sign Catalogue which is the subject of this
paper. For the creation of a text corpus and a
dictionary of an only partially understood language
and script, a Sign Catalogue, an inventory of all
used signs, is an indispensable instrument. At the
same time, the catalogue also forms the core
component for constructing a machine-readable text.
The project deals with a writing system that is only
partially deciphered. The investigation of the script
and language has produced numerous assumptions
and interpretations about the reading of its signs.
For a heuristic deciphering work, these reading
hypotheses are to be included for further investigation.
During the development of the Sign Catalogue, a
system for the qualitative evaluation of
decipherment hypotheses and reading proposals was
developed. Among other things, it offers assistance
with the linguistic analyses of the texts. The
challenge in modelling this system was to represent
several reading proposals, as well as to determine
the factors that led to the formulation of the
respective deciphering hypothesis. The goal of knowledge
representation is also the explicit description of
the methods applied. This enables the scholar to
carry out analyses and draw conclusions on the
3. https://www.iae.uni-bonn.de/
4. https://www.sub.uni-goettingen.de
basis of the model. The modelling of reading
proposals and their plausibility act as examples for
the representation of complex knowledge objects
with interpretive character, as they are typical for
research data in the humanities. In this context,
the paper emphasizes the role of knowledge
representation in projects that are located in the digital
humanities and considers the challenges posed by
the modelling of vague and uncertain information.
2</p>
    </sec>
    <sec id="sec-3">
      <title>Characteristics of Classic Maya writing</title>
      <p>Compared to other Mesoamerican writing systems,
such as Isthmic or Aztec, Maya writing has a
considerably long time of use, about 2,000 years. The
first pre-Classic texts were written in the 3rd
century B.C. The writing tradition reached its peak in
the Classic period (100 - 810 A.D.). The arrival of
the Spaniards lead to a deep cut in Maya culture
that also affected the use of their writing. It was
only possible for the Maya to use it in secret. In the
underground, hieroglyphic writing continued until
the late 17th century, and ceased to exist thereafter.
It was only due to 18th and especially the 19th
century explorers who brought Maya texts back
to light, and with that further and further into the
focus of research. To date, an estimated 10,000
text carriers (Figure 1) have survived, mainly
monumental inscriptions such as altars and stelae.
Numerous texts can also be found on ceramics and
small artefacts, like jewellery, implements or boxes.
Of special importance are the codices written on
paper-like material, of which unfortunately only
four have survived.</p>
      <p>The Maya writing system is characterised by
an iconic character, hence labelled a hieroglyphic
script. Typologically it is a logo-syllabic system
which is characterised by two main sign classes:
logograms and syllabograms. Logograms stand
for linguistic terms, like e.g. PAKAL for ‘shield’,
and refer, with only a few exceptions, only to one
denotation. Syllabograms represent single vowels
and syllabic components and serve to write
lexical and grammatical morphemes. They are also
used as phonetic complements of logograms, as
in PAKAL-la. Words could thus also be written
exclusively with syllabic signs pa-ka-la (Figure 2),
but mostly, both sign classes were combined in
writing (Diehr et al., 2017, 1186).</p>
      <p>
        The signs were arranged in almost rectangular
blocks. Such a hieroglyphic block probably
corresponds to the emic idea of a word. Within a
block, the signs could be arranged in many
different ways. Depending on space requirements and
aesthetics, they could merge, overlap, be infixed,
or rotated. The blocks were usually arranged in
double columns and read from left to right and
top to bottom. The sentences constructed this way
form complex texts with a syntax and structure
still preserved in modern Mayan languages
        <xref ref-type="bibr" rid="ref24">(Prager,
2014a)</xref>
        . Maya writing shows a distinct calligraphic
complexity, as we can observe a broad graphic
variability of signs. It allowed to write aesthetically
sophisticated texts without necessarily repeating
identical variants. For a linguistic expression, there
is not only a single graphic correspondence, but
usually several, sometimes very different, variants.
The bipartite syllabogram u could either be
written in its full form or alternatively with only one
of its two segments. These segments could also
be reduced or multiplied. As a further example,
the syllablic sign yi shows how simple forms can
be transformed into so-called head variants. Even
diagnostic features (marked in Figure 3) are not
present in all graph variants. It was even possible
to insert or parenthesise other graphs, as the
example ma shows (Figure 3).
      </p>
      <p>
        The way in which variants are formed has not
yet been the subject of systematic investigations
before. There are a few individual studies by
        <xref ref-type="bibr" rid="ref1 ref2">Beyer
(1934</xref>
        a; 1934b; 1936; 1937) and
        <xref ref-type="bibr" rid="ref15">Lacadena (1995</xref>
        ,
of published sign inventories shows between 700
and 1,000 signs with a phonemic value. These
comprise, according to own estimates, about 3,000
distinctive graph variants.
3
      </p>
    </sec>
    <sec id="sec-4">
      <title>Sign catalogues as classification aids</title>
      <p>The study of the hieroglyphs is carried out on the
basis of previously discovered text carriers.
However, many text carriers have been destroyed over
time, are forgotten in archives and museums,
hidden in private collections, or have simply not yet
been discovered. Therefore, there will always be
a small number of signs that could not be
inventoried. On the other hand, it can be assumed that
new discoveries will be made in the coming years.</p>
      <p>Early in 2018, the results of a large-scale aerial</p>
      <p>
        Lidar prospection in Guatemala were presented,
Figure 3: Graph variants showing a much denser concentration of
archaeological sites in the tropical lowlands than previously
assumed, also implying a larger number of text
204 ff.) that investigate substitutions, rotation prin- carriers
        <xref ref-type="bibr" rid="ref6">(Clyens, 2018)</xref>
        .
ciples, or symmetries. In the course of the pre- The discovery of new inscriptions and thus the
paratory work for the digital Sign Catalogue, we discovery of previously unknown signs represents
recognised for the first time that there are general a challenge for the classification of Maya signs.
rules and principles for the formation of graphs Previous sign inventories could, of course, only
which can be derived and defined by graphotactic consider the signs known at the time for a printed
analyses 5. In total, we have identified 45 individual publication. The discovery of new signs has to be
variation principles that can be divided into nine anticipated in the digital Sign Catalogue, also a
posclasses (mono-, bi-, tri-, and variopartite, division, sible re-classification of already known signs. We
animation head, animation figure, multiplication, therefore need flexible data management processes
extraction). for new research results.
      </p>
      <p>
        Another feature is the polyvalence of signs. A Compared to other ancient languages and
writsingle glyph can either be read as a logogram or a ing systems, the decipherment of Maya writing is
syllabogram, depending on context. For example, relatively recent. Although it was known since the
the sign with catalogue number 528 can be used 19th century that many texts contain readable dates
as the logograms TUN (‘stone’) and CHAHUK
        <xref ref-type="bibr" rid="ref19">(Morley, 1915)</xref>
        , a historical character and thus a
(name of the 19th day in the Maya calendar), or as representation of spoken language was rejected
the syllabogram ku. The graph variant used does
        <xref ref-type="bibr" rid="ref27">(Thompson, 1956, 169)</xref>
        . It was not until the 1950s
not indicate which of the readings is to be applied. that Yuri Knorozov recognised the logo-syllabic
      </p>
      <p>
        This impressively illustrates how free Maya scribes character of Maya writing
        <xref ref-type="bibr" rid="ref10">(Knorozov, 1952)</xref>
        and
were in the design of their texts. It also explains the was able to present the first linguistically viable
challenges faced in the still ongoing decipherment readings. Although his research appeared in
Engprocess. Especially the graph variations make the lish translation in 1958
        <xref ref-type="bibr" rid="ref12">(Knorozov and Coe, 1958)</xref>
        ,
determination of graphemes and their allocation the Cold War left his work mostly unnoticed by
to a specific linguistic expression difficult. Until researchers for a long time.
today, the exact number of signs and their vari- The hieroglyph catalogue by J. Eric S. Thompson
ations could not be determined exactly. A review
        <xref ref-type="bibr" rid="ref28">(Thompson, 1962)</xref>
        contains several multiple and
false classifications, but it still serves as the
stand5. This classification was first presented at the conference ard reference for sign classification and subsequent
“tÄhegyApctaodloegmisychoef S‘Bciiennsecnes’-aWnedisLhieteitreantuIrIeI”inwMhicahintzoookn pAlapcriel a8t, transliteration in preparation for linguistic analyses,
2016
        <xref ref-type="bibr" rid="ref22">(Prager and Gronemeyer, 2018)</xref>
        . even though Thompson did not provide any
readings in rejection of Knorozov’s works
        <xref ref-type="bibr" rid="ref24">(Prager, 2014a)</xref>
        . humanities that aims to represent objects and the
A total of nine other sign inventories have been knowledge about them in a data model. In Sowa’s
published so far. They all have incorrect classi- sense, this means making the semantics of
knowfications, particularly problematic are the multiple ledge objects explicit and transferring them into a
classifications of signs in which several allographs data model (Sowa, 2000, 132). We call the
‘knowof a grapheme were inventoried as different signs ledge object’ the epistemic notion of specific
entit
        <xref ref-type="bibr" rid="ref14 ref7">(Grube, 1990; Kelley, 1962; Kurbjuhn, 1989; Riese, ies that constitute themselves in a specific
know2006; Ringle and Smith-Stark, 1996)</xref>
        . The cata- ledge context. Knowledge objects do not exist
logues are mostly simple graph inventories. It was by themselves. They are created by
knowledgenot until Knorozov’s “Compendio Xcaret”, pub- generating processes; they are formed from
statelished posthumously in 1999
        <xref ref-type="bibr" rid="ref11">(Knorozov, 1999)</xref>
        , ments, analyses and interpretations about specific
that readings were linked to the corresponding entities that are the object of interest. We call the
graphemes for the first time. However, these are specific knowledge context from which questions
based on the state of research of the 1960s. Even to the object arise ‘domain’. The process of
modelthe two most recent catalogues show readings only ling knowledge objects and their specific domain
in an unreflected manner. can be subdivided into the following steps: (1)
ana
      </p>
      <p>With our digital Sign Catalogue we want to con- lysis of domain-specific requirements, (2)
knowsider both expression levels of a sign, the functional- ledge representation by conceptual modelling and
linguistic and the graphemic, and model them in (3) construction of a machine-readable model.
such a way that the assignment of both levels to
each other is accurate and flexible. A further disad- 4.1 Analysis of domain-specific requirements
vantage of traditional character catalogues is that
they are unchangeable due to their printed
edition and therefore cannot be dynamically
extended. This prevents misclassifications from being
corrected or new relations between signs from
being established. Here, too, a catalogue in digital
format can remedy the situation by being able to
react flexibly to changes while at the same time
offering persistent identification possibilities.
4</p>
    </sec>
    <sec id="sec-5">
      <title>Modelling of the digital sign catalogue</title>
      <p>We are developing our digital Sign Catalogue with
the aim of carrying out a complete new inventory
of Maya signs and thus making a reliable statement
on the number of currently known signs. With the
Sign Catalogue we establish a new concept for the
systematisation and classification of signs. The
specific characteristics of the complex Maya
writing system are explicitly represented in the model:
Graph variants, multifunctional characters and
multiple transliteration values are defined and related
to each other. Particular attention is paid to reading
hypotheses, which are not only documented in the
catalogue, but also qualitatively evaluated
according to explicit criteria, so that they can be prepared
for later analysis.</p>
      <p>In order to develop a Sign Catalogue in a virtual
environment, the signs and their properties must be
represented in a machine-readable model. We
understand modelling as a research method of digital</p>
      <p>Requirements for the Maya Sign Catalogue are
to be determined by intensive exchange and
transfer of knowledge between domain experts and the
modeller. In the process, specific requirements are
defined for the model, its implementation in a data
cataloguing system and technical environment. To
do so, we chose a procedure based on the method
of an expert interview. According to Reinhold,
this represents an adequate method of information
needs analysis particularly in the context of
modelling research processes and research data in the
digital humanities, since a high degree of implicit
knowledge is to be expected on part of the
researchers (Reinhold, 2015, 330). However, it should be
noted that experts only share goal-oriented
knowledge if the questioner already has a high level
of expertise on the subject (Flick, 2007, 218 ff.).
The process thus requires a high degree of
familiarisation with subject on the part of the modeller,
who must be able to describe the respective domain
from a disciplinary point of view.</p>
      <p>The process of defining requirements represents
the most interdisciplinary area in joint project work.
According to an explorative-hermeneutic working
method, we proceeded as follows: The first step
was to incorporate the basic concepts of the
domain, i.e. linguistics and grammatology. We also
analysed the subject, the Sign Catalogue, for its
importance as an essential tool for decipherment,
as well as its function specific to the project and
discipline. Furthermore, an intensive analysis of
the structure of the Maya writing system was
carried out with the aim of explicitly representing its
signs and their function in the model. The resulting
minutes of the discussions formed the basis for a
catalogue of requirements, which serves as a
working paper to determine further requirements and to
specify existing ones.
4.2</p>
      <sec id="sec-5-1">
        <title>Knowledge representation by conceptual modelling</title>
        <p>We are convinced that the process of knowledge
representation is a hermeneutic method aimed at
constructing a machine-readable model.
Conceptual modelling defines what Sowa calls ‘ontological
categories’. They determine everything that can be
represented in a computer application (Sowa, 2000,
51). The creation of an ontological model aims to
explicitly describe knowledge objects, their
relationship to each other, and to their domain. The
definition of these categories is particularly difficult
when it comes to vague and uncertain information:
“any incompleteness, distortions, or restrictions in
the framework of categories must inevitably limit
the generality of every program and database that
uses those categories” (Sowa, 2000, 51). Since
‘knowledge’ about objects can be questioned or
interpreted differently, it is necessary to represent
the various levels of knowledge in the model in
order to counteract such distortions and to limit
the knowledge base precisely in the sense of the
defined ontological categories.</p>
        <p>
          First, we scanned through specialised literature
and linguistic vocabularies such as the SIL
Glossary of Linguistic Terms
          <xref ref-type="bibr" rid="ref16">(Loos et al., 2003)</xref>
          for
definitions and concepts to describe writing systems and
signs. However, the materials showed that most
concepts are not reusable for our model because
they already focus too much on applicability in a
particular linguistic context. Our aim, however,
is to define ontological categories for the
representation of signs and their function in a writing
system. Linguistic categories can only be applied
on a meta-level (Diehr et al., 2018, 38).
        </p>
        <p>Based on the literature and the outcomes of the
requirement analysis, we modelled concepts and
their relationships to each other and to their domain
in an ontology using OWL syntax. Figure 4 shows
the domain model of the ontology and illustrates
the core concepts and their relationships to each
other.</p>
        <sec id="sec-5-1-1">
          <title>In our understanding, a sign is constituted by the</title>
          <p>conjunction of two different levels: 1) a
linguisticfunctional level, which, according to Ferdinand de
Saussure, contains the notion and the pronunciation
(de Saussure, 1931, 28 ff.) as well as the specific
function of the sign in its writing system; and 2) a
level of graphic representation which contains all
possible forms of expression reflecting the concept
of the linguistic-functional level.</p>
          <p>Consider a Maya sign as an example: it has the
verbal utterance yi and thus fulfills the function of
a syllabic sign. For the syllabogram yi there are at
least three different graphical forms of
representation (see Figure 3). This form of representation
is called a graph.6 A graph is an abstract, typed
form of an individually realised sign. The graph of
yi in the variation ‘anthropomorphic head variant’
recorded in the catalogue represents a type which
prototypically represents all individual writing
variants and thus all actual occurrences for yi in the
form of a ‘head variant’.</p>
          <p>
            All graphs that are assigned to a shared linguistic
expression stand in an allographic relationship to
each other and in their totality form variants of the
grapheme of the sign
            <xref ref-type="bibr" rid="ref5">(Bussmann, 2002, 294)</xref>
            . A
graph can only be assigned to exactly one
linguisticfunctional expression (idiomcat:Sign). This
relation (idiomcat:isGraphOf) is optional, so that also
graphs can be inventoried which could not be
assigned to a ‘sign’ yet.
          </p>
          <p>The function of a sign within the
writing system is called a sign function
(idiomcat:SignFunction). For Classic Mayan, besides
the two main classes logogram and syllabogram
(idiomcat:SyllabicReading), two additional
functions were defined, since Rogers (2005, 10) also
includes numerals (idiomcat:NumericFunction) and
diacritics (idiomcat:DiacriticFunction).
Logograms are further subdivided by their function: We
differentiate between those that have a deciphered
phonetic value (idiomcat:LogographicReading)
and those for which only a semantic field can be
narrowed down (idiomcat:LogographicMeaning).7
6. The term ‘graph’ chosen by the project as the concept of
the abstract, typified form of a realised character is still under
discussion within the project. Since in linguistic discourse
the realised character is commonly referred to as ‘graph’, the
abstract form represents a kind of prototype of the graph.
Here it is still to be considered how such a typification can
be considered in an intermediate step between the realised
graph and the graphem. For example, the typed form could
be considered as meta-graph or proto-graph in contrast to the
graph.
7. This distinction may be irrelevant for sign classification
In the catalogue, we also document reading
hypotheses and evaluate their plausibility
(idiomcat:ConfidenceLevel). Therefore, a distinction
of the logograms is necessary because different
evaluation criteria (idiomcat:parameter) have to
be applied to each. In the linguistic analysis
of the corpus it also makes sense to distinguish
between phonetic values and a meaning. Both
are represented as transliteration values
(idiomcat:transliterationValue) in the model.
4.3</p>
        </sec>
      </sec>
      <sec id="sec-5-2">
        <title>Construction of a machine-readable model</title>
        <p>Once the objects have been defined, their structure
and relationships to each other have been
represented in a conceptual model, the data model can be
developed. Concepts and structures are translated
into a machine-readable form by formulating them
in a syntax suitable for representing the conceptual
model. Since the Sign Catalogue was designed as
an ontology, a data structure is required that can
represent semantic relations between uniquely
referenceable entities.</p>
        <p>We use the virtual research environment
Textin general, since the function of the character is one and the
same for the writing system. However, with the ontology we
model a specific use case: The Sign Catalogue serves as an
instrument purposing the deciphering of the Classic Mayan
writing system.</p>
        <p>
          Grid
          <xref ref-type="bibr" rid="ref20">(Neuroth et al., 2015)</xref>
          for the administration,
creation, and presentation of the data generated in
the project. For data acquisition, we use the RDF
input mask of the TextGrid Lab, which we adapted
to our project-specific needs. The mask renders
HTML forms to enter data on the basis of an RDF
schema in TURTLE syntax. In order to make the
input mask usable for the Sign Catalogue, the model
designed as an ontology must be transferred into
an RDF schema.
        </p>
        <p>This illustrates that data modelling often requires
pragmatic decisions. Since the functionality of the
input mask is based on an RDF schema in TURTLE
syntax, it was not possible to directly use the
ontology written in OWL. This is not a problem in
the present case, since the OWL schema could be
transferred lossless into an RDF schema. In our
scope, the expressiveness of the triple structure is
sufficient to represent the complexity of the
ontological relationships defined by the conceptual
model. However, the generated data is stored in a
triple store. With the use of the Query Language
SPARQL sophisticated queries are possible.</p>
        <sec id="sec-5-2-1">
          <title>In addition to the aim of representing knowledge</title>
          <p>objects and their domain in a machine-readable
model, interoperability with other systems and
schemata plays an important role in the
development of data models. The adoption of already
defined concepts enables the exploitation of the
potential of existing metadata standards: Their
integration improves the searchability of ontologies and
increases both their quality and that of the
applications accessing them, since the knowledge base
is continuously enriched (Gradmann et al., 2013,
275 ff.). Simperl names the following steps for the
reuse and integration of ontologies: 1) Search for
reusable ontologies, 2) integration-oriented
evaluation, and 3) integration of ontologies into the own
model (Simperl, 2010, 246).</p>
          <p>The chances of finding already existing
ontologies are low if they are subject-specific and thus
often only known in the respective domains. The
ontologies developed in these domains are
obviously very specific and/or geared to a specific
application, which makes their immediate reuse and
the integration of concepts more difficult.8</p>
          <p>
            Therefore, it makes sense to use so-called
toplevel ontologies in addition to subject-specific
ontologies. Top-level ontologies make it possible to
reach agreement on generally valid concepts that
do not have to be redefined in one’s own scheme
            <xref ref-type="bibr" rid="ref17">(Milton and Smith, 2004, 85)</xref>
            .
          </p>
          <p>While searching for reusable ontologies for the
Sign Catalogue we came across ‘General Ontology
for Linguistic Description’ (GOLD).9 With the
aim to define basic categories and relations for the
scholarly description of human language, the
ontology seemed to be reusable for our purposes. In the
integrated evaluation it turned out that it focuses on
grammatical rules with morphosyntax as a starting
point (Farrar and Langendoen, 2003, 100). In our
context, the concepts defined in GOLD could only
be used to a limited extent, since our concept
represents a meta-level that serves for the organisation
of signs. Nevertheless, some concepts provided a
good starting point for the definition of our schema.
The definition of gold:FeatureStructure as “a kind
of information structure, a container or data
structure, used to group together qualities or features
of some object” (Farrar, 2010) is so general that
our definition of the class idiomcat:SignFunction
as “a feature assessed to a Sign[,] [t]he nature of
the feature is specified by the subclasses” 10 could
8. This is also true for the ontology of the Sign Catalogue: It
was developed specifically for the needs of the project. Even
though, it can principally be abstracted for other applications.
9. http://linguistics-ontology.org/gold
10. Ontology of the Sign Catalogue for Classic Mayan
https://classicmayan.org/documentations/
catalogue.html
be modelled as a subclass of gold:FeatureStructure.</p>
          <p>The evaluation of suitable top-level ontologies
showed that the CIDOC Conceptual Reference
Model (CIDOC CRM), despite its focus on
describing processes for documenting cultural
heritage objects, contains many meta-concepts that are
suitable for modelling our catalogue. In this
regard, most classes have been defined as subclasses
of CIDOC CRM, for example classes ‘Sign’ and
‘Graph’ were defined as specific sub-concepts of
crm:E33_Linguistic_Object as they are
“identifiable expressions in natural language” (Doerr et al.,
2011).
5</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>Development of a system for the qualitative evaluation of decipherment hypotheses</title>
      <p>In our Sign Catalogue we want to consider
published as well as own reading hypotheses,
especially since the readings are used for the linguistic
analysis of the text corpus for the compilation of
the dictionary.</p>
      <p>
        Even though research is working with erroneous
catalogues, the decipherment of Maya writing has
significantly advanced in recent decades. In the
1980s, David Stuart presented an important study
        <xref ref-type="bibr" rid="ref25">(Stuart, 1987)</xref>
        that gave the decipherment process
new impetus. Nonetheless, there is no consensus
about the reading for all signs. The reasons why
signs are not equally deciphered can be manifold,
for example if a sign is only attested once, or
if there are no indicators pointing to phonemics.
Since decipherment has mostly been carried out by
individual epigraphers using isolated examples in
‘hand-picked’ texts, they have never been checked
and compared using a complete text corpus, since
it does not yet exist and is only being developed
by the project now. Not only for these reasons
different reading hypotheses were and are presented
for many signs. Individual interpretations of the
context or linguistic basics also contribute hereto.
5.1
      </p>
      <sec id="sec-6-1">
        <title>Development and plausibility of reading hypotheses</title>
        <p>From a grammatological point of view, different
categories of deciphering can be defined that are
linguistic and semantic, extended after the sign
function by Riese (1971, 20-23) and deciphering
criteria by Houston (2001, 9 ff.). The phonetic
content of linguistically secured signs can be
verified in a number of contexts, often with semantic
and lexical agreement in morphographs, sometimes
also with polyvalent readings. With operational
readings, the sound value can be inferred on the
basis of certain indications, such as vowel harmony
rules, phonemic complements, or the semantic field.
However, multiple reading proposals that are not
polyvalent and have different plausibilities may
also occur, based on the individual interpretation
of the context or the knowledge of the material. In
some cases, only parts of the phonetic content can
be isolated due to a lack of indications, such as
the final sound through complements. However,
semantics and almost always the word class can often
be narrowed down from only partially readable or
undeciphered signs, either because of the context
or also because of the iconicity of the graph. About
one third of the sign inventory resists any
reasonable interpretation so far, mostly morphographs
and among these mostly nouns.
5.2</p>
      </sec>
      <sec id="sec-6-2">
        <title>Definition of propositional logics to determine confidence levels</title>
        <p>Since each sign function fulfills a different
linguistic function, each requires the creation of its
own set of criteria to test a decipherment
hypothesis. For example, a logogram cannot appear in a
stem medial position of a word, whereas a syllable
character can (criterion ‘m’). The evaluation of a
decipherment is qualitatively done by combining
certain criteria in propositional logics, which
indicate the plausibility in disjunct numerical values.
Each sign function has a different number of
plausibilities. If new texts add new occurrences with
criteria that have not been considered so far, these
can be supplemented. For example, the following
criteria have been defined for the syllabic signs:
d = Landa’s Manuscript
l = Consonant in Landa’s Alphabet
u = Vowel in Landa’s Alphabet
k = Complete logographic substitution
t = Partial logographic substitution
a = Allographic substitution
o = Preposed to deciphered logogram
c = Postposed to deciphered logogram
f = Stem initial
m = Stem medial
g = Word medial
r = Word final
y = Ergative spellings
s = Correspondence with image
q = Correspondence with object
b = Doubling is possible
v = Vowel harmony
i = Lexical correspondence with graph icon</p>
        <p>These are combined in four propositional logics
to determine four plausibility levels:
1 (excellent) = d _ u _ (k ^ (s _ q)) ^ (a ^ ( f _
m) ^ (s _ q)) _ ((o _ f _ m _ y) ^ (g _ r _ c) ^ (s _ q))
2 (good) = (t _ o _ c) ^ v ^ (s _ q)) _ (a _ o _ f _
m) ^ (g _ r _ c)) _ (g _ r _ c) ^ (s _ q)) _ ( f _ m) ^
(s _ q))
3 (partial) = t _ c _ l _ r:v
4 (weak) =</p>
        <p>g _ m _ r
The criteria and propositional logics were
developed under critical consideration of the
existing decipherment practice. In an account
from about 1566, we actually have a contemporary
description of the Maya script (de Landa, 1959,
104 ff.), even if it was considered as an alphabet
then. Nonetheless, the manuscript contains
annotations to certain hieroglyphics with a syllabic
value, which then brought the key to decipherment.
Even before Knorozov it was known that there
was a strong text-image relation in the codices.
Thus Paul Schellhas was able to isolate the proper
names of different gods in a structuralistic way
(Schellhas, 1897). This also turned out to be
helpful for decipherment. Among the examples
with a syllabic annotation in said manuscript there
are also &lt;cu&gt; and &lt;ku&gt; (ku and k’u in today’s
orthography). These examples are therefore
deciphered only by criterion ‘d’, as they are
supported by a contemporary witness, further
criteria would be exclusively complementary. Both
signs can be found in the initial position (criterion
‘f’) in hieroglyphs that identify animals that are
also depicted in the corresponding image: a turkey
and a vulture (Figure 5). Colonial dictionaries
provide kutz and k’uch for the two animals. Thus
we also have a hypothesis to the sound of the
second syllabograms (tzV and chV), but without
knowing the vowel, because both hieroglyphics are
not present in Landas list. Criterion ‘r’ is fulfilled
and level 3 is reached.</p>
        <p>But the sign tzV appears in the initial word
position among the depiction of a dog, attested as tzul
in the dictionaries. Thus the syllabic value tzu is
confirmed and the sign becomes level 2, in
connection with the image even to level 1 (criterion ‘s’).
The second sign is therefore lV; the initial sound
is confirmed by the annotation &lt;L&gt; for a very
similar sign in the manuscript. The examples have so
far shown vowel harmony (CV1-CV1), so that the
reading might be lu, which would be level 2.</p>
        <p>Final proof comes from a stem medial
attestation. In the calendrical structure of an almanach,
we find three hieroglyphs where the number ‘11’
should appear, which is spoken buluk. Indeed, with
the spelling bu-lu-ku, the assumed vowel can be
confirmed here, and the sign is deciphered on level
1.
6</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>Methods and techniques for the creation of a machine-readable corpus</title>
      <p>
        One objective of the project is to create a
machinereadable corpus of all inscriptions. Due to the
complex graphemics, the sign polyvalence and the low
decipherment status, it is not possible to capture the
text in phonemic-transliterated values. Therefore,
it is not surprising that there is currently no
standardised machine-readable font, such as Unicode,
available for the Maya script. There are efforts in
this direction
        <xref ref-type="bibr" rid="ref22">(Pallan Gayol and Anderson, 2018)</xref>
        ,
but in their current form they do not meet the
classification requirements of the Mayan script.
      </p>
      <p>In the text corpus we would like to refer to the
graph variants used in each case, in order to carry
out investigations for the use of the writing in its
spatial-temporal development and its use
depending on the text carrier, its location as well as the
text contents.</p>
      <p>
        We encode the text corpus in XML using the
TEI-P5 guidelines
        <xref ref-type="bibr" rid="ref26">(TEI, 2018)</xref>
        . In order to
distinguish the structure, the arrangement of the glyphs
and other inscription-specific phenomena, we have
developed a TEI-compliant, application-specific
schema. Instead of using phonemic-transliterated
values, we use Semantic Web technology to refer
in the XML document to the resource stored in
RDF. In the Sign Catalogue, each graph variant is
recorded as an independent resource and thus has
a URI. In the TEI-encoded text we tag each glyph
with the element &lt;g&gt; (character or glyph) and use
the attribute @ref (“points to a description of the
character or glyph intended”)11 to refer to the
respective URI (Figure 6). The text itself consists
of external resources and together with the Sign
Catalogue forms an ontologically linked system.
      </p>
      <p>With this approach, we also take into account the
requirement to consider different deciphering
hypotheses. Since the text corpus refers to the graph,
which is potentially associated with several
possible reading proposals in the digital catalogue, it is
now possible to analyse the inscription under
consideration of various hypotheses. A further
advantage of this approach is that new decipherments can
be flexibly integrated. Even in the case of newly
11. http://www.tei-c.org/release/doc/
tei-p5-doc/en/html/ref-g.html
formulated, reliable statements, these do not have
to be elaborately incorporated into the corpus. By
using URIs, it is possible to clearly reference the
corresponding resource in the Sign Catalogue. The
encoding of the corpus text itself does not change,
it remains stable.
7</p>
    </sec>
    <sec id="sec-8">
      <title>Data publication and reuse possibilities</title>
      <p>The cataloguing and classification of Maya signs
is a continuous process. Through ongoing
research, new findings will repeatedly lead to
reclassifications. In the scope of our project, a first
new inventory will be completed in the course of
2018. As soon as all graph variants and signs have
been recorded, the encoding of the inscriptions and
the compilation of the corpus will begin. The
documentation of the texts and text carriers will extend
over the remaining duration of the project until
2028. The data will successively be made
accessible on our project portal,12 which is currently in
the conception stage. Furthermore, the corpus data
will also be published in the TextGrid Repository
(TG Rep),13 where they can also be accessed by
external users via OAI-PMH. The RDF data of the
Sign Catalogue will be also retrievable at the portal
via a SPARQL endpoint and also at the TG Rep.
All schemata created in the project can be
downloaded from the public area of our Git repository14
and can be used under a CC BY-4.0 license. The
documentation of the Sign Catalogue ontology is
also available as a website.15
8</p>
    </sec>
    <sec id="sec-9">
      <title>Conclusion: modelling as a research method</title>
      <p>Modelling processes bring about a reflection of the
definitions and methods of the respective discipline,
12. https://www.classicmayan.org/
13. https://textgridrep.org/
14. https://projects.gwdg.de/projects/
documentations/repository
15. Ontology of the Sign Catalogue for Classic Mayan
https://classicmayan.org/documentations/
catalogue.html
which poses questions to knowledge objects and
their domain. The representation of this knowledge
in a machine-readable model requires the precise
definition of the objects as well as their
relationships to each other and to their knowledge base.
Specialist traditions are questioned and applied
methods are checked for their fundamentals. In the
case of modelling the deciphering hypotheses, it
became clear that statements about the plausibility
of reading proposals can only be made on the basis
of formal evaluation criteria. Without reflection
on the intuitive-pragmatic evaluation mechanisms,
no evaluation system could have developed that
operates on the basis of formalised and
logicalcategorised parameters.</p>
      <p>Modelling thus makes a central contribution to
the research methods of the Digital Humanities
by stimulating the reflection on the generation of
discipline-specific knowledge through conscious
questioning. The modelling process produces
explicitly defined objects and relationships that are
transformed into machine-readable data and data
structures. This transformation process makes the
knowledge objects and their knowledge base
available for further analysis, whether hermeneutical or
quantitative.</p>
      <p>Laser scans</p>
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https://news.nationalgeographic.com/2018/
02/maya-laser-lidar-guatemala-pacunam/.
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de Saussure, Ferdinand (1931). Cours de linguistique
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pages 1185–1196. Bonn: Gesellschaft für Informatik.
doi:10.18420/in2017_120.</p>
      <p>Diehr, Franziska, Sven Gronemeyer, Christian Prager,
Maximilian Brodhun, Elisabeth Wagner, Katja
Diederichs, and Nikolai Grube (2018). Ein
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noch nicht entzifferte Schrift der Klassischen Maya.
In Christian Wartena, Michael Franke-Maier, and
Ernesto De Luca, eds., Knowledge Organization
for Digital Humanities. Proceedings of the 15th
Conference on Knowledge Organization WissOrg’17
of the German Chapter of the International Society
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Mayaschrift von der Protoklassik bis zur spanischen
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