=Paper=
{{Paper
|id=Vol-2604/paper26
|storemode=property
|title=Ontologies as a Set to Describe Legal Information
|pdfUrl=https://ceur-ws.org/Vol-2604/paper26.pdf
|volume=Vol-2604
|authors=Anatolii Getman,Volodymyr Karasiuk,Yevhen Hetman
|dblpUrl=https://dblp.org/rec/conf/colins/GetmanKH20
}}
==Ontologies as a Set to Describe Legal Information==
https://ceur-ws.org/Vol-2604/paper26.pdf
Ontologies as a Set to Describe Legal Information
Anatolii Getman1[0000-0002-1987-2760], Volodymyr Karasiuk1[0000-0001-9092-2137]
and Yevhen Hetman2[0000-0002-1801-7252]
1
Yaroslav Mudryi National Law University, Kharkiv, Ukraine
2
National Academy of Law Science of Ukraine, Kharkiv, Ukraine
karasiuk@yahoo.com
Abstract. The article discusses the features of legal knowledge ontology crea-
tion. It is determined that ontology is the most appropriate way to describe legal
knowledge. The particular qualities of legal information and the features of the
language of a right were investigated. A review of legal knowledge ontologies
that are used in various branches of law was made. The properties of legal in-
formation and the requirements for regulatory documentation in Ukraine were
described. The formalization of the structure of the ontology database was pre-
sented, taking into account the required attributes of the concepts. The method-
ology of the work with the knowledge base was proposed to use the independ-
ent work of many users. The legal knowledge ontology at the law university
was filled by all users of the software package, but experts checked the quality
of this content. Crowdsourcing was considered as the main technique of the on-
tology filling process. Several branches of the ontology of legal knowledge
were filled. The results of the experimental operation of this ontology by uni-
versity students were analyzed.
Keywords: artificial intelligence, legal information, ontology, knowledge rep-
resentation, crowdsourcing
1 Introduction
The legal systems of continental Europe, including Ukraine, use regulatory law. That
is, they pay more attention to judicial interpretation in assessing legal facts and ac-
tions than to judicial precedents. Therefore, the regulatory framework (legislation)
first of all is to be easy of access and simply ordered. For many practical areas of ap-
plication of law information should also be available on the daily activities of legal
structures, that is, by-laws and regulations (on a second-priority basis). A modern way
of structuring legal knowledge is to describe them using ontologies. Based on legal
ontologies and inference rules, automated decision-making methods in the field of
law can be implemented. However, to create legal ontologies, it is necessary to con-
duct a legal analysis by the efforts of legal experts and knowledge specialists. Fea-
tures of the application of legal information requires the concept of legislative defini-
Copyright © 2020 for this paper by its authors.
Use permitted under Creative Commons License Attribution 4.0 International (CC BY 4.0).
tions and attributes of regulatory documents in which they are introduced and used.
One more serious problem is the organization of the process of filling the ontology
with relevant content. In this process, enormous amounts of legislative (and regulato-
ry) information as well as the presence of collisions and confusion of terminology are
complicating conditions. With regard to legal information for application software, it
is to be noted the high variability of its content. Continuous changes in the regulatory
framework are difficult to track and model in the ontology. It is impossible to rely on
only the efforts of legal experts to fill the ontology, due to its volume. In this case,
you can count on the use of crowdsourcing and advanced rules for working with the
content of the ontology.
The ideas and approaches considered in this article were implemented in the pro-
cess of creating an ontology, which is applied in the educational process at the univer-
sity. The present article is a further development of the ideas contained in [1-4].
2 Particular Qualities of Legal Information
Legal information has a great importance for the functioning of modern society. Due
to its significance, it has significant features and otherness. Characteristics of legal
information and the legal language in Ukraine in general are given in detail in reviews
[5, 6].
With regard to legal terminology, it is special because of its versatility, since any
social activity is closely linked to law. A clear definition and unambiguous interpreta-
tion of legal terms is an extremely important condition for becoming constitutional
state, contributes to the improvement of legislative activity, the effective implementa-
tion of legislative acts, creates the conditions for their ordering and systematization of
legislation. In order to carry out its functions, the term must satisfy the requirements
that are scientifically substantiated and legally binding. Most experts consider sys-
tematic, accurate, unambiguous, stylistic neutrality (lack of emotionally expressive
marking) and motivation to be inalienable attributes of the legal term.
Regulatory and legal terminology, moreover, are characterized by multi-
component quasi-terms - long-term descriptive turnovers of different structures that
give a fairly accurate definition of the subjects and objects of specific relationships
and their interaction, thereby reflecting the essence of legal relations in each case,
which is regulated in this case regulatory act.
There are certain rules for using regulatory terminology when creating legal docu-
ments [7]. And the volume of by-laws (instructions, regulations, certificates, and oth-
er) is generally difficult to assess.
3 Formulation of the Problem
The main purpose of this research are: explore legal information to spot features that
are fundamental to the formation of the electronic structure of legal knowledge; study
the problem area of knowledge engineering to build legal information ontology, and
then provide an ontology model and technology to work with it. Features of legal in-
formation imposes their requirements on the structure of the ontology and the rela-
tionship between concepts. Attributes of concepts are very important for practical
activities in the field of law. The task is also to investigate the crowdsourcing method
for ontology filling-in.
4 The Use of Ontologies to Represent the Legal Information
Intelligent knowledge-based systems have various models of data processing and dis-
play. The most common in practice are taxonomies, semantic networks, and ontolo-
gies.
Taxonomy. Taxonomies display hierarchy of concepts associated subordination re-
lation, wherein each subsequent level taxonomy includes previous subtypes. Formally
taxonomy can generally be described: T = C, H , where C is the set of terms (con-
cepts), H - hierarchy relationships between terms (concepts).
Semantic network. Network models represent a directed graph wherein vertices -
are concepts and arcs - the relationship there between: N = C, R , where C is the set
of terms (concepts), R - set of relationships between concepts. This is the closest
view to what natural language information appears. Network model at the same time
does not give an idea of the domain hierarchy; in addition, the creation and modifica-
tion of the subject area model is difficult; moreover, for the processing of network
models a special apparatus for formal inference and planning is necessary [8].
Ontology. Ontologies are a variety of frame models that are used to describe re-
sources in WEB applications, corporate databases, document processing applications,
and the like [9-11]. Ontologies have a large number of element types and relation-
ships between them. Ontologies contain such elements: concepts (notions), classes,
relations, interpretation functions. Concepts are objects - the vertices of the ontology
graph that have their own semantic representation; classes combine many of the same
type of concepts. Relationships and interpretation functions define the relationship
between terms and their properties.
Ontology should introduce a minimum basic set of concepts, but sufficient for
modeling purposes, and given the description of complex situations, determine the
ratio between these concepts, their characteristics, effectively transmit certain value
concepts necessary to describe situations and interpretation functions.
A more relevant definition of ontology is given in the IEEE Std 1872 ™ -2015
standard: ontology is the basis that defines the main concepts, their properties, rela-
tionships between concepts and domain rules. Taxonomies provide an ordered set of
vocabulary and a single type of relationship between the terms, and an ontology pro-
vides more relationships, restrictions, and rules. Ontologies provide relevant
knowledge about the subject area explicit in a computer-interpreted format, which
allows software (SW) to reason about this knowledge to output new information. On-
tologies are an excellent tool to reduce the ambiguity in transferring knowledge be-
tween groups of people, information systems, knowledge bases, control systems and
other objects that are built on the same abstraction [12].
With regard to law, ontologies here allow us to emphasize [13, 14] the relationship
of legal norms with each other; the relevance of official legal conclusions; take into
account the degree of priority of legal norms; the identity of the diverse branches of
law and more. Ontological engineering in law therefore has its own characteristics: 1)
a large number of generally accepted concepts with their own specific application; 2)
the difference in the structures of various branches of law; 3) the presence of a general
theoretical legal level between the ontology of the upper level and the ontology of the
subject area; 4) a large number of theoretical assumptions and abstract constructions,
which depend on the specifics of legal views. Therefore, it should be considered that
the most effective approach is founded on the learning of the terminology of law and
the construction of ontologies on large text blocks.
Today, reliable methods for creating ontologies have not been created, and there is
no methodology for a comprehensive assessment of ontologies. Although general
approaches imply the idea of an assessment [15]: epistemological identity (clarity,
intuition, relevance, completeness), executive authenticity (sequence, computability),
the possibility of multiple use (task and method, subject area). These criteria are antic-
ipated to be developed for use as a standard for describing all ontologies.
In Ukraine, work on the creation of legal ontologies is also underway [16 - 18].
5 Overview of Legal Information Ontologies
Currently, a large number of software packages have been developed that implement
information systems in law based on ontologies. Consider the most interesting.
PrOnto [19], the ontology is designed to describe information about products and
their groups, and is currently effectively used to describe the GDPR (General data
protection regulation). This ontology considers the GDPR as a starting point, however
it is meant to be extended to the concepts and relative relations of other legal frame-
works.
LRI-Core - ontology, which covers all branches of law. Book [20] illustrates the
use of LRI-Core for legal ontologies in the Netherlands.
CLO – (Core Legal Ontology) SLO is an instrumental framework for building le-
gal ontologies for any branches of [21].
LKIF - is, first of all, several libraries of related concepts and their properties.
LKIF is a universal means for the legal domain [22].
LTS - Legal Taxonomy Syllabus - is an ontology-based legal curriculum [23].
Eurovoc thesaurus - is a multilingual thesaurus that forms the basis of domain
names for the European Union terminology database. Eurovoc is available in 23 offi-
cial languages.
Eunomos - is a software for managing legal documents and terminology. Eunomos
is focused on tracking changes in regulatory documents. This software supports mul-
tiple languages and focuses on many areas of application in various branches of law.
LegalRuleML - a package that uses Legal XML to represent a model of legal
knowledge and uses the rules to build a legal ontology. It includes NLP tools. Very
interesting project.
NRV - following development of LegalRuleML, which contains a set of basic
primitives for identification and classification.
ODRL - a structured language focused on legal support of open licenses in publish-
ing digital data on the network - photos, software, news and other data.
LDR - a modification of the language ODRL, which is focused on the use of model
LOD, including the multilingual data.
CC - language for describing the use of Creative Commons copyright licenses.
RDF concept used.
L4LOD - ontology for one problem area - for a universal description of licenses in
a computer network for data exchange.
ELI - ontology for a standardized description of European law through XML. This
ontology can be used online on the internet.
LOTED2 - legal ontology, which provides information on tendering in Europe. It
supports the legal grounding for purchases.
PPROC - an ontology in which a semantic description is used to support public
procurement procedures. Ontology prevents misconduct in procurement.
And other ontologies [24, 25].
6 Features of Legal Knowledge Ontology
The mathematical description of the legal ontology that we are developing is pre-
sented in detail in [3].
Features of legal information that were considered earlier should be taken into ac-
count when developing an ontology scheme:
- the presence of a synonymous description of some legal terms (nodes of ontolo-
gy);
- the presence of restrictions on the duration of wording of a legal term;
- the presence of a mandatory relationship between definitions (ontology nodes)
and strict wording (legislative definitions) in regulatory documents.
-and more others.
That is, the database implements the ontology, includes the following parts:
- concept (legal term) and connections;
- connections of groups of synonyms of legal terms;
- texts - definitions of legal terms in accordance with regulatory documents;
- lexical mapping of legal terms and relationships;
- indices the use of legal terms and relationships in the source document.
More about each part.
• concept and relations: are recorded with unique identifiers, with a name string for
output in the graphical interface.
• texts - definitions of legal terms: presented in the form of sentences, with fixation
of belonging to the section and the text, that is, among them the following entities can
be distinguished:
- text - in accordance with the structure of the normative document, this is a se-
quence of paragraphs, type, title, list of service attributes of the document;
- paragraph - description of the structure of the part of the document, which in-
cludes the title of the paragraph, the sequence of blocks and separate sentences of the
text;
- sentence - a structural unit of the source text in the form of a string and the type
of sentence (indicating membership in the source regulatory document or its para-
graph).
Fig. 1 schematically shows the hierarchy between the legal term (concept), sen-
tences, groups of synonyms.
Fig. 1. The structure of concepts and their relationships in the ontology database.
The problem of terminological confusion. The basic principle of legal technology
requires that different terminology in one text designate different legal phenomena.
Moreover, ideally, they try to extend this principle to the entire legal system as a
whole, so that only one term answers each legal phenomenon within it. This problem
is not confined to the particular case of terminological confusion in any particular
document - it is quite common, has long been known and has deep roots. One can find
a series of many terminological inconsistencies and contradictions in the Ukrainian
legislation. An analysis of the laws of Ukraine from the point of view of their termi-
nological certainty gives reason to conclude that the meaning of the term used in one
law is not always the same in content with the term contained in another law. Howev-
er, this is due to the fact that in addition to general legal terminology, which combines
the basic terms of the entire system of legislation, there is intersectoral and industry
terminology. Tautological constructions, polysemy and the like lead to confusion in
understanding the regulatory requirements of the laws of Ukraine [26].
In addition, conflicts between the provisions of regulatory documents of various
branches of law are not uncommon. In the era of the widespread dissemination of
electronic documents, digital databases and systems of related documents, the prob-
lem of adhering to terminological unity and its gradual implementation in current leg-
islation and practice of its application is of fundamental importance. The terminologi-
cal toolkit gives lawyers such an opportunity. However, on February 4, 2020 Law No.
469-IX was introduced to improve the electronic form of workflow in the Verkhovna
Rada. Previously, it was assumed that publications on the Verkhovna Rada website
are considered the official publication of laws (along with the publication in the Voice
of Ukraine newspaper and in the Verkhovna Rada Vedomosti). Now the official is
considered the publication of laws and other acts of the Verkhovna Rada in these me-
dia. That is, the electronic form of the document was made dependent on the printed
form. And the issues of streamlining the conceptual and terminological apparatus of
legal information remain relevant for modern Ukrainian jurisprudence. Naturally,
when creating an ontological structure, these circumstances should be kept in mind.
7 How to Work with This Ontology
Crowdsourcing. Only the efforts of experts are not enough to build ontology of this
scale. In addition, the legal knowledge system is very dynamic, «alive». One can re-
call Wikipedia, which was filled by everyone and a high level of reliability of the in-
formation contained in it. It means that the approach does works.
A number of projects for the creation and improvement of ontologies are known in
which the crowdsourcing method was applied [27, 28].
We managed to attract a significant group of students to fill the ontology. As part
of the training course, they analyzed the information of the subject area, identified
concepts, and created (filled) the ontology. The work was carried out under the gen-
eral guidance of a teacher, and after acquiring some experience, without assistance.
The results turned out to be rather optimistic both in relation to the initial ontology,
covering one subject area [4].
The completion of the first stage of creating an ontology of legal knowledge
showed the following results. The quality of extracting legal concepts from legislative
documents and textbooks was 90%. Students identified and contributed a total of
more than 6,000 legal terms. Experts noted some of the shortcomings identified in the
ontology. Students were not able to correctly identify some concepts that have com-
plex definitions consisting from several words. Conversely, several concepts were
defined verbose, more complex than they actually were. Also, when filling in the on-
tology, some concepts were not placed in the branches where they should have been
located according to the hierarchy of concepts. However, in general, the result is quite
good.
8 Discussion
After creating the ontology, it is necessary to evaluate the characteristics and reliabil-
ity of the obtained ontology. In accordance with [29], evaluation is required through-
out the entire ontology life cycle. However, in analyzing the different methods for
evaluating of an ontology it is to be noted that the proposed metric [30] difficult to
apply ontologies in various problem areas that have serious differences of the struc-
ture and output functions.
Ontology can be actively used if it is complete and has a convenient interface. Us-
ers got used to modern information systems with a developed interface. Shortcomings
in the interface repel potential users.
The experience of filling and training operation of an exemplary ontology has
shown that the problem of updating (supplementing) the ontology with new concepts
is acute. Users rarely refer to concepts that are needed infrequently, and these branch-
es remain unfilled. That is, to achieve perfect coverage of the subject area is very dif-
ficult. Perhaps, when scaling the system, with the access of a huge number of users
(all at once), this problem will be solved, as is now the case on Wikipedia — the clas-
sic crowdsourcing system.
Organizing the process of filling the legal ontology, there is a proposal on the fea-
sibility of forming an ontology at the time of adoption and the description of the nor-
mative act, due to a competent and proper analysis of correlation of concepts by ex-
perts in the divisions of the Verkhovna Rada are responsible for work with legal in-
formation.
In any case, ontologies are a better mechanism than using XML markup of legal
documents. Although it requires large expenditures for maintenance and development.
The lack of state support for the development and filling of legal ontology dooms
dozens of enthusiastic groups to proactive, unrelated (multidirectional) work in this
area.
9 Conclusions
As a result of the study, analysis of the advantages and disadvantages of various
knowledge representation systems, it is advisable to use an ontological representation
to describe legal knowledge.
The full implementation of the task of developing an ontological description of le-
gal information allows lawyers to provide a tool for access to relevant regulatory in-
formation in real time. And given the volume of the regulatory framework and its
variability, this will have a great practical effect.
In the framework of this work, the structure of the ontology database is formed, the
structure takes into account the attributes of concepts related to legislative definitions
and the time frame of validity of regulatory documents.
The created ontology is filled with key concepts of one branch of law (which is
considered as the core on the basis of which a full ontology will be developed). This
ontology is used in the educational process for specially prepared tasks in the study of
selected topics.
To fill in the ontology, the crowdsourcing method was used with the attracting of a
sufficient number of law students. We hope that with the accumulation of experience
with the created ontology, the quality of filling in the ontology will increase.
Based on the work performed, promising for future work, we consider the follow-
ing:
- development of automatic ontology comparison tools, which will be an important
tool for assessing the completeness, consistency of ontologies created by different
users, as well as comparing ontologies of different branches of law (or ontologies of
different countries);
- development of an interface in a natural language, to attract non-professional us-
ers of information systems to work.
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