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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Intelligent Tools for the Semantic Internet Navigator Design</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Igor-kuz@mtu-net.ru somin@post.ru</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Proceedings of the 14</institution>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Igor Kuznetsov © Mikhail Charnine © Elena Kozerenko © Nikolay Somin © Vladimir Nikolaev © Andrey Matskevich Institute of Informatics Problems of the Russian Academy of Sciences</institution>
          ,
          <addr-line>Moscow</addr-line>
        </aff>
      </contrib-group>
      <fpage>222</fpage>
      <lpage>231</lpage>
      <abstract>
        <p>This paper describes the methods and instruments for semantic web navigator design which is a novel system providing semantic drive for Internet users. The solutions proposed rest on the statistical paradigm for knowledge extraction and the semantic presentations based on the Extended Semantic Networks (ESN) mechanism. The approach presented comprises rule-based and stochastic techniques for text processing and extracted entities and relations mapping onto the structures of the knowledge base.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1 Introduction</title>
      <p>
        The paper deals with the issues of design an
development of the new tools comprising the intelligent
methods and systems based on the presentation
mechanism of the extended semantic networks (ESN)
[
        <xref ref-type="bibr" rid="ref1">1</xref>
        ] which had been employed for creation of a wide
range of knowledge-based systems and the features of
the keywords encyclopedia Keywen [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
      </p>
      <p>As a result of tremendous growth of the Internet, its
users receive huge volumes of information as responses
to their Internet queries. Users are interested in a big
variety of questions, they make their own attempts to
employ keywords and phrases by means of test and
error method (addressing search machines and making
analysis of the answers). This results in tremendous
expenditures of labour and disappointment because of
huge amounts of irrelevant information and/or its
incompleteness.</p>
      <p>Hence, to make optimal queries, one has to face the
problem of requests ordering, reflecting interests of
users, creating directories of subjects and articles. It is
necessary to create special means, which allow users to
find what interests them in the sea of information with
reduced expenditures of labour. On-line encyclopedias
play the role of such means.</p>
      <p>The intelligent web navigator comprises the features
of the ESN linguistic processors which were developed
for different classes of information systems relating to
the artificial intelligence research field.</p>
      <p>The core feature of the development is assigning a
semantic structure to natural language input. Semantic
structure is obtained via the semantic categorization and
establishment of semantic relations between concepts
presented in natural language texts contained in
Internet. Association is the dominant type of semantic
relations supported by the intelligent tools under
discussion. The study of the contexts and co-occurrence
of terms and key words allows to shape the semantic
structure of the navigated texts and perform automatic
categorization.</p>
      <p>The hybrid approach is taken for the semantic
navigator design which incorporates the logical
analytical functionality of the intelligent systems based
on the extended semantic networks, statistical methods
and machine learning mechanisms.</p>
    </sec>
    <sec id="sec-2">
      <title>2 The ESN Intelligent Systems and their evolution</title>
      <p>
        The intellectual systems, developed on the basis of the
apparatus of the extended semantic networks (ESN) [
        <xref ref-type="bibr" rid="ref1 ref4 ref5 ref6">1,
4-6</xref>
        ], called the ESN-systems, were created by the
association of developers, including the authors of this
article at the Institute of Informatics problems of the
Russian Academy of Sciences during the period of two
decades within the framework of research projects and
applied systems, oriented at the concrete subject areas
and customers.
      </p>
      <p>We single out 4 generations of ESN- systems. The
linguistic semantic ideas laid as the basis of the systems
of this class underwent a specific evolutionary process.
Intellectual ESN- systems contain the developed bases
of knowledge, in this case the knowledge is represented
in the form of the records in the language of the
extended semantic networks, called ESN - structures.
LТnРuТstТМ knoаleНРe Тs, tСus, a “speМТal Мase oП
knoаleНРe” anН Тt Тs also representeН Тn tСe Пorm oП tСe
records in the language of the extended semantic
networks. Basic structural element of the ESN is the
named N-arв preНТМate, МalleН “ПraРment”. TСe аСole
set of language objects are given in the form of
predicate-argument structures, in this case the
mechanisms for presentation of embedded structures are
supported, which gives very powerful presentation
mechanisms for describing the objects of different
language levels.</p>
      <p>The uniformity of language presentations is a very
important factor. In the process of analysis and
synthesis of natural language sentences the formal
grammatical apparatus, similar to the dependency
grammar, is used. With this approach the words and the
constructions, which perform the role of predicates in
tСe sentenМe, are tСe “support” elements, anН tСe result
of the analysis of a sentence must become one
predicate, which corresponds to the predicate of the
sentence (i.e. to basic verb in the tensed form or to
another basic predicate expression) in question. Thus, in
the process of analysis, in the first place, the processing
Тs perПormeН oП tСe “aМtТon аorНs” anН tСe “relatТon
аorНs”, Т.e., of the verbs and other words, which have
syntactic-semantТМ ЯalenМes. An eбample oП a “relatТon
аorН” tСe аorН “ПatСer”, “ПrТenН”, anН tСe lТke, Т.e., Тn
tСТs Мase a “relatТon” Тs a аorН аСТМС assТРns stronР
clearly expressed syntactical-semantic expectations.</p>
      <p>
        Semantic analysis in the engineering linguistic
understanding is the process of translation of natural
lanРuaРe eбpressТons Тnto “Тnternal” struМtures oП tСe
knoаleНРe base (KB) Тn our Мase tСese “Тnternal”
structures are the records in the ESN language. Thus, a
KB structure is the code of sense in the intellectual
information systems. The language engineering
solutions were implemented in the systems with
“Мomplete” lТnРuТstТМ analвsТs, tСeses are tСe sвstems oП
the 1st and 2nd generations: DIES1, DIES2, Logos-D
Д1, 4] anН tСe sвstems аТtС “ПaМtoРrapСТМ” approaМС, Т.e.
the intelligent systems of analytical decisions support
(ISADS) [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], where the goal of analysis is the extraction
of entities and connections from the texts, these are the
systems of the 3rd and 4th generations.
      </p>
      <p>The ESN systems of the 4-th generation perform
the tasks os semantic objects (named entities)
extraction. The set of the objects to be extracted
depends on the tasks of a user. At the same time the
quality of a linguistic processor is to a considerable
degree determined by the possibilities for this
extraction. The basic types of information objects and
connections, extracted by the ESN semantic processors
are given below:
• persons (bв ПamТlв name, РТЯen name anН patronвmТМ
- FNP) with their role features (criminal, victim);
• tСe Яerbal НesМrТptТon oП tСe persons, tСeТr НТstТnМtТЯe
signs;
• aННress, postТnР ТnПormatТon attrТbutes;
• Нate(s) mentТoneН;
• аeapon аТtС Тts speМТal Пeatures;
• telepСone numbers, faxes, e-mails with their
subsequent standardization;
• tСe means oП transport аТtС tСe ТnНТМatТon oП tСe
vehicle type, its state number, color and other attributes;
• passport Нata anН otСer НoМuments аТtС tСeТr
attributes;
• eбplosТЯes anН narcotic substances;
• orРanТгatТons, posТtТons;
• quantТtatТЯe МСaraМterТstТМs (Сoа manв persons or
other objects participated in an event);
• tСe numbers oП aММounts, sums oП moneв аТtС tСe
indication of the currency type;
• terrorТst Рroups anН orРanТzations;
• partТМТpants oП terrorТst Рroups аТtС tСe ТnНТМatТon oП
their roles (leader, head of, etc.);
• tСe armeН ПorМes, assТРneН Пor antТterrorТst Мombat
(Military_.Force);
• eЯent (МrТmТnal, terrorТst, bТoРrapСТМal, anН so on) аТtС
the indication of the information objects participation in
them;
• tТme anН tСe plaМe oП eЯents;
• tСe МonneМtТon betаeen НТППerent tвpes oП ТnПormatТon
objects (with whom a person works in an organization,
or lives at the same address, in what events participated
together with other objects, etc.). For extracting objects
all versions of an object name including the brief form
possible in the text were considered. Standard objects
(names, dates, addresses, the forms of weapon and
others) are reduced to one (standard) form.</p>
      <p>The identification of objects is performed taking
into account brief designations (for example, separate
surnames, patronymics, initials), anaphoric references
(indicative and personal pronouns, for example, "this
person", "it...") definitions and explanations (for
example, "the mayor of Moscow Sobianin" is identified
with the subsequent words "mayor", "Sobianin").</p>
      <p>For the extraction of events and connections the
analysis of verbal forms, participial and adverbial
constructions is carried out. An important task is the
identification of objects in the entire text, the use for
these purposes of indicative pronouns, brief names,
anaphoric references.</p>
      <p>Taking into account the difficulties and in
accordance with the tasks the linguistic processor
Semantix was developed, which achieves normalization
of words, their grouping with the formation of units, the
identification of objects and the establishment of
connections. As a result for each NL document a
semantic network called the meaningful document
portrait was constructed automatically. The latter are
the knowledge structures of the knowledge base which
serve the basis for implementing different forms of
semantic search : the search by features and
connections, the search for the objects connected at
different levels, the search for similar figurants and
incidents, the search by distinctive signs (with the use
of ontologies).</p>
      <p>The extraction of connections is not only the deep
analysis of verbal and other forms. Many connections
are given on default. For example, in the summaries of
incidents, as a rule, figurants names are followed by
their data without the indication of their belonging and
with the additional text insertions. For that the directed
search for the connected objects, i.e., the restoration of
connections, default data is organized in the processor
Semantix.</p>
      <p>Special processes are organized in order to connect
persons with their place of stay or place of work,
vehicles which belong to them, and so forth. For
example, the analysis of the summaries of incidents is
performed as follows. For a number of objects (address,
telephone, date of birth, etc.) a virtual connection with
other objects (names, organizations), is built thus yet
unidentified. Then, at the same level of processing their
search is performed with the aid of the special rules for
identification. In these rules the direction of search, the
permissible quantity of steps, and also the signs of
words and punctuation marks, where the process of
search ends are indicated. In this case special filters are
required, in order not to take and not to connect an alien
object.</p>
      <p>
        This approach showed sufficiently good results in
the system Criminal [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. The special features of natural
language are considered where the same actions are
identified with the aid of the verbs, verbal nouns and
participial constructions. Presented in ESN they are
reduced to one form, i.e. a complex object. Moreover,
forms with verbal nouns can be the components of
verbal forms. On analogy, in ESN some objects can be
the components of others. The reason- consequence and
temporary dependences between actions, events, etc. are
represented which reflect the logical connection of
sentences, assigned explicitly, with the aid of the words
“tСereПore”, “tСen”, etМ. The quality of a linguistic
processor is determined by a number of factors. First,
the possibility for isolation of objects and connections.
These are the types of objects being isolated, their
quantity. The Semantix processor identifies up to 40
types of objects, including very complex ones, which
correspond to actions and events. With an increase in
the quantity appear the additional difficulties, connected
with collisions of the extraction rules of: some rules can
seize the words, which relate to other objects and those
extracted by other rules.
      </p>
      <p>It becomes important to consider the order of the
application of rules, including of the rules of
identification. In the second place, an important factor
is the selectivity of rules and procedures of the
identification: the factor of the noise and losses. By
noise we mean the presence of excessive words in the
objects. Losses are the situations when an object is not
revealed or revealed partially: in the text there are the
words, which did not enter into the object. In the
Semantix processor the rules are arranged in such a way
that they ensure the high degree of selectivity and the
minimization of noise and losses with the large number
of the objects being selected.</p>
    </sec>
    <sec id="sec-3">
      <title>3 Conceptual linguistic simulation</title>
      <p>
        Conceptual linguistic simulation (CLS) is the process of
constructing a natural language model of a subject area
(SA) (Fig.1), that synthesizes in itself the approaches of
conceptual and linguistic simulation [
        <xref ref-type="bibr" rid="ref4 ref5 ref6">4-6</xref>
        ].
1. The analysis of the texts
&gt;2.
      </p>
      <p>Singling out the basic
concepts and characteristics
&gt;3.</p>
      <p>Constructing a subject area
vocabulary founded on the
basic “world model”</p>
      <p>The basic “world model”</p>
      <p>and the language model
&gt;4.
&gt;5.</p>
      <p>Establishment of the type-kind
relations between SA notions</p>
      <p>Formulation of the situational
rules in the form of IF… THEN</p>
      <p>rules
Construction of the conceptual linguistic model of a
certain subject area is subdivided into the following
stages: - construction of the conceptual model proper,
i.e., the ramification of fundamental notions, their
organization in kind-type trees and the determination of
the connections between them; - the development of the
ideographic dictionary for the subject area, i.e., the
lexical population of the conceptual model; - the
introduction of the base rules, which describe "the
model of the world" in the natural language relevant for
the subject area.</p>
      <p>The procedure of conceptual-linguistic simulation
on the basis of the ESN apparatus is based on the
following principles:</p>
      <p>• tСe model must be "open" , i.e., support the
effective mechanism of expansion and information
update;</p>
      <p>• tСe moНel oП tСe “sense” presentatТon sСoulН
consider the facts of extra-linguistic reality, which in
the form of rules and relations compose a certain basic
"world model" and the concrete models of subject
areas;</p>
      <p>• tСe moНel sСoulН be practical, i.e., not overloaded
by the detailed descriptions of connections and relations
between the concepts in order to ensure the possibility
of its realization, but at the same time, it should reflect
the relevant information for specific objectives.</p>
      <p>A realistic approach to the formulation of the
problem dictates the need of limitation to a
domainoriented subset of a natural language. The essence of
limitations consists in the following: - first, analyzed
text materials contain expert knowledge from particular
subject areas (we developed the systems for the subject
areas for the diagnostics of the microcircuits production
failures, forecast in the social sphere, criminology, and
others); - in the second place, for the purposes of the
maximally possible elimination of ambiguity, dictionary
is built according to the modular principle: there is a
certain most general common part (1-2 levels)
completed by special dictionaries for each particular
subject area.</p>
      <p>The proposed model of lexical semantics is based on
the principle of the "nuclear" value realized in the
context of this subject area with the subsequent
inductive supplementation of other meanings (if they
are actualized in the contexts in question). The
taxonomy is also used which is realized in the form of
the hierarchical trees of the word classes. The general
"world model" of the system serves as the basis for the
subject area models.</p>
      <p>The classes of words, are subdivided into
concept/names, relations, actions, properties,
characteristics of actions, time and place locatives. The
most Рeneral notТon Тs “МonМept”, or unТЯersal Мlass,
which is subdivided into object, the situation, process
and others. The words which relate to the classes of
actions and relations, are represented as the
semanticsyntactic frames, which determine the
predicateargument structures (government model).</p>
      <p>However, in the described approach (let us name it
the ESN-approach) the range of argument values is
substantially extended. This extension consists in the
fact that in the role of arguments there can appear
simple objects corresponding to the individual words,
structural objects which present word combinations,
phrases and clauses, and concept of "case" includes not
only semantic, but also syntactic aspects. The approach,
based on ESN allows to reflect the arbitrary level of the
structures embedding it makes it possible to reflect the
structural nature of lexical semantics, which in this
model has a hierarchical network structure.</p>
      <p>Linguistic knowledge is represented in the system
dictionary and the declarative modules of linguistic
processor. In the ESN systems the function of
dynamically formed semantic dictionary which is
expanded automatically by the system in the course of
concrete texts processing is also realized on the basis of
initial linguistic information.</p>
      <p>In FТР. 2 tСe “Тnternal” НesМrТptТon oП tСe Яerb Тn tСe
semantic dictionary is represented. This dictionary is
automatically generated by the ESN-systems DIES2,
LOGOS-D, IKS in the course of natural language texts
processing.</p>
    </sec>
    <sec id="sec-4">
      <title>4 General Considerations for Encyclopedia</title>
    </sec>
    <sec id="sec-5">
      <title>Design</title>
      <p>Encyclopedias traditionally played an important part in
the study of new material. However, their creation in
electronic type – is a huge work which requires not
simply to enter the adequate material into computer, but
also and its additional ordering: creation of subject
directories for allocation of main classes and subclasses,
definition of main notions, building of hyper-references
for communication of entries (articles) of encyclopedia
between themselves, but also of references to primary
sources. What should be also considered is the
dynamism of circulating in Internet information:
emergence of new information sources, which should
be taken into account in encyclopedias.</p>
      <p>In FТР. 2 tСe “Тnternal” НesМrТptТon oП tСe Яerb Тn tСe
semantic dictionary is represented. This dictionary is
automatically generated by the ESN-systems DIES2,
LOGOS-D, IKS in the course of natural language texts
processing.</p>
      <p>At present the majority of large electronic
encyclopedias operating on-line have been created on
the basis of printed materials of universal
encyclopedias: Big Soviet Encyclopedia, Britannica,
Big Brockhaus, Big Larousse and others. Creation of
such encyclopedias requires considerable human labour.</p>
      <p>The above said leads us to the conclusion that the
global problem in the present situation is the
development of methods and program means for
automation of the most labor-consuming stages of
formation of on-line Internet encyclopedias.</p>
      <p>Such formation requires elements of intellectual
activity: for making the choice of the subject for
description, formation of articles (entries), their names,
search for definitions, etc. Development of concepts of
on-line encyclopedia results in reference systems of a
more general plan, providing collection of information
and systematized knowledge representation about
different objects which are of interest to the user:
about politicians, persons of science, of culture; - about
organizations, companies; - about events (for example,
strikes, their reasons, place and time); - about goods and
objects of a particular class (for example, fuel, mining,
region) and others. While building such systems, many
common problems appear, that are also vital for on-line
encyclopedia.</p>
      <p>The only difference is that instead of articles and
their names there would be other objects.</p>
      <p>
        At present the decision of the discussed problems
becomes real because there have been designed and
developed many systems and facilities in the areas,
connected with creating different classes of intelligent
systems, language processors, knowledge bases,
statistical processing of language components [
        <xref ref-type="bibr" rid="ref1 ref10 ref11 ref12 ref13 ref14 ref2 ref3 ref4 ref5 ref6 ref7 ref8 ref9">1-14</xref>
        ].
      </p>
      <p>The given work is based on the experience of
creation of the on-line encyclopedia and is devoted to
the principal directions of decision methods
development for the mentioned problem.</p>
    </sec>
    <sec id="sec-6">
      <title>5 Special Features of Automation</title>
      <p>In general, the problem looks like this. The input
comprises a stream of documents from Internet (all
relating to a determined application domain). The
output is an electronic encyclopedia consisting of brief
articles with names, with hyper-references between
articles (if the names of other articles are encountered in
the text) and with hyper-references to primary sources
the documents from Internet.</p>
      <p>In addition an electronic encyclopedia should
include the main menu, article sections, various
classifiers and the internal search system, providing
quick access to concrete subjects making application
domain. Certainly, to automate all this processes is not
possible.</p>
      <p>Formation of the main menu, subjects and query
facilities is done manually. Computer can help with
selection of material of articles and the choice of their
meaningful components.</p>
      <p>Two stages are distinguished: training and
operation. The grade level, when training sample is
given to the system (documents from Internet) with
indicated articles which the system should select.</p>
      <p>For example, types of diseases can be, symptoms,
texts of description, falling into, say, preventive
maintenance of diseases and of others. The system
should develop decision rules providing allocation of
these articles at the stage of operation on other
documents.</p>
      <p>Such rules are founded on statistical treatment with
discovery of keywords and standard contexts
(meaningful components), providing selection of
articles.</p>
      <p>Grade level allows to partly or completely automate
the activity of a developer in discovery of the data,
necessary for system operation. Discovery of keywords
and of contexts requires the use of morphological and
semantic blocks of analysis of natural language (NL).</p>
      <p>The first block converts word forms
e.g. TABLE, of TABLE, to TABLE
into the uniform type (TABLE) and is particularly
important for languages, where words have the a
system of cases and other morphological information
as, for example, the Russian language.</p>
      <p>Without such transformation the search in documents
for the same components becomes extremely difficult.</p>
      <p>The second block selects word-combinations (they
can also be with names of articles) and verbal forms,
that determine context in most cases.</p>
      <p>Both these blocks of the language processor
implementing the analysis of natural language sentences
plays an important part in the system.</p>
      <p>In creation of on-line encyclopedia important are the
following factors: the quality of a created encyclopedia
(it is determined by the vicinity to the existing
encyclopedia); the difficulty of the preparatory stage
including creation and input of basic materials
(dictionaries, catalogues and others.) necessary for
system operation; also development of a system
teaching to discovery of articles is a very difficult
programming task.</p>
      <p>Simplification of the second and the third factors
can dramatically decrease the quality. At the same time,
an “oЯer-МomplТМatТon” oП the task should be avoided.</p>
      <p>We follow the scheme when the development is
conducted in stages: first a simple system is developed
with subsequent enforcement of its features.</p>
    </sec>
    <sec id="sec-7">
      <title>6 Semantic Navigator: Encyclopedia of</title>
    </sec>
    <sec id="sec-8">
      <title>Keywords</title>
      <p>
        In 2002 the first version of the on-line encyclopedia [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]
was released by Michael M. Charnine, having received
the name Encyclopedia of keywords largely basing on
the methods described above. The Encyclopedia
functions on the web-site: www.keywen.com. It
constantly grows and at present contains more than
250000 articles on different subjects in different
languages. The majority of the articles are English, but
there are also more than 3800 German and 1300 Italian
articles. The Encyclopedia of keywords is universally
recognized in Internet. Daily several thousand people
have free use of its information.
      </p>
      <p>Each article of Encyclopedia consists of key
sentences (of phrases). Each of them contains one or
several key words. Such phrases are found in Internet
with a special semantic navigating program, that is
named Keywen Encyclopedia Bot.</p>
      <p>At present Encyclopedia contains more than 5
million key-phrases. The major part of the articles of
Encyclopedia begin with the section, in which the
definitions of terms, included into the article title are
given. This allows to understand quickly what the
article is about. If a more profound study of the given
subject is required, it is possible to use the references to
Internet sites. Each phrase is supplied with such
reference in Encyclopedia. Each clause of Encyclopedia
contains a list of the most important keywords. For each
keyword in an article there is a section in which
examples of phrases, containing this keyword are given.</p>
      <p>The knowledge of keywords is necessary for
automatic development of exact requests to search
machines. For example, for the article Knowledge
Discovery a typical structure in the paragraph
DEFINITIONS is given: " Knowledge discovery is the
extraction of implicit, previously unknown and
potentially useful knowledge from data". An article
contains references to more specialized articles:
Business and Companies, Magazines and,
Organizations, Text Mining, Tools. An article contains
keywords (with examples of phrases) KNOWLEDGE
DISCOVERY, DATA MINING, INTERNATIONAL
CONFERENCE, KDD and others. Encyclopedia
(Keywen. com) that contains internal search machine
allows to quickly find all key-phrases and appropriate
clauses, containing this or that key word. As a result for
any keyword it is possible to quickly find application
domain corresponding to it. At the beginning of 2004 a
version was created of electronic encyclopedia of the
Open Project type entitled "Encyclopedia of key
phrases". In the framework of this project each user of
Internet can bring some contribution into the
development of Encyclopedia. The facilities to move
sections of any article according to their value and also
enter new phrases in Encyclopedia are given to each
user.</p>
      <p>For Keywen development a constantly growing
multilingual texts corpora automatically extracted from
Internet is used. For each subject domain and for every
supported language a particular text corpus is formed.
The text corpora are analysed by the linguistic
processor.</p>
      <p>Keywen NLP pipeline includes:
a text tokenization module,
a part-of-speech tagging system,
a sentence boundary detection tool,
a collocation identification module,
a named entity recognizer,
a word sense disambiguation system,
a full-syntactic parser.</p>
      <p>Extraction of term candidates from
domainoriented texts supports Automatic Term Recognition
resulting in Multilingual terminology</p>
      <p>Reordering the list of extracted candidates is based
on the term/keywords candidate relevance ranking.</p>
      <p>Extraction of key phrases and definitions provides
Automatic summarization of domain-oriented texts
using TF/DF measure</p>
      <p>Extraction of key phrases and definitions creates
Knowledge-Rich Contexts, automated pattern
acquisition is used for the identification of semantic
relations: associations and family trees which serve the
basis for semantic parser. There are a number of useful
advantages of the Keywen apparatus, including, but not
limited to: the ability to build large scale
humanreadable and semantic-oriented hierarchy of categories;
the ability to generate dynamical and flexible
hierarchical categories; the ability to accept
contributions of users with different qualification for
improving hierarchical categories; the ability to accept
user’s mТnТmal МontrТbutТons (as lТttle as one МlТМk); tСe
ability to have multiple ways to categories in the
polyhierarchy and at the same time to have
hierarchical/directory paths of the categories.</p>
      <p>The Keywen apparatus produces a "concrete"
substantially repeatable result. It generates hierarchical
categories that are substantially repeatable. If users
were to perform the claimed steps on multiple different
occasions using the same inputs (e.g., the same
collection of related terms, the same communication
with input/output module), the users would achieve the
same result on each occasion. The functionality of the
technique has been mathematically proven, the present
apparatus for generating hierarchical categories do not
use any empiric, heuristic, or fuzzy considerations.</p>
      <p>The following two basic category systems are
currently most popular:</p>
      <p>- Hierarchical, as in directories (easier for
understanding, planning and processing);</p>
      <p>- Multi-hierarchical, as in Wiki-encyclopedias (more
natural, flexible and easy to maintain).</p>
      <p>The category structure of Keywen is the product of
these two systems: it has advantages of both and opens
greater possibilities than either. Both the structure of
web-directories and structure of Wiki-encyclopedias
may be viewed as an isolated case of Keywen Category
Structure. The category structure of Keywen is more
precise, logically correct, flexible and dynamic. It is
convenient for effective navigation and fast
understanding, helps:
- to see the BIG PICTURE,
- to divide knowledge into parts and select the most
important parts,</p>
      <p>- to create effective plans for learning and
knowledge processing.</p>
      <p>Hierarchy is a form of organizational structure in
which each unit has one and only one "parent" unit,
except the "top" unit, which has none.</p>
      <p>A Polyhierarchy (multi-hierarchy) is like a
hierarchy, but nodes can have multiple parents. In
mathematical terms, polyhierarchy is represented by a
directed acyclic graph, or a partially ordered set. In
terms of object-oriented methodology, it can be viewed
as class hierarchy with multiple inheritance.</p>
      <p>Directory structure is a particular case of
hierarchical structure (that is more general concept). For
example, UNIX and DOS have a hierarchical directory
structure that allows files to be organized by categories.
The main difference between hierarchical and directory
structure is different naming convention for categories.</p>
      <p>The category names in directory structure can be full
or short (local). The full category names in a directory
usually are equal to their paths from Top category. A
directory contained inside another directory is called a
subdirectory of that directory. Subdirectories are
specified by concatenating the subdirectory short name
to the name of the directory above it in the hierarchy.
Together, the directories form a hierarchy, or tree
structure.</p>
      <p>Keywen Category Structure is a polyhierarchy
(multi-hierarchy) that contains one preferred (primary)
hierarchy (tree) which contains all nodes.</p>
      <p>The following new technologies are employed in
Keywen:</p>
      <p>- One-click Keywen technology and electronic
Voting System,
- Keywen search engine with large queries,
- Keywen Writing Service.</p>
      <p>These technologies can accelerate the encyclopedia
РroаtС anН Мan make a аrТter’s аork most eППeМtТЯe.</p>
    </sec>
    <sec id="sec-9">
      <title>7 Prospects for the development of</title>
    </sec>
    <sec id="sec-10">
      <title>Semantic-Focused Systems</title>
      <p>The development trends "Encyclopedias of keywords"
and "Encyclopedias of key phrases" are determined as
follows:
- constant increase of the encyclopedia articles number
in different European languages, including Russian,
inter-referenced between the relevant articles in
different languages;
- the speed of updating of Encyclopedia will be
increased; old articles will be kept in the archive of
Encyclopedia, but fresh articles will occupy their place
with references to the new phrases and new articles
from Internet;
- the Rating of articles self-descriptiveness will be
constructed; for this it is necessary to analyze several
million references contained in Keywen.com: those
containing more key phrases to a given issue, should get
high position in the rating.</p>
      <p>Further stages of development are connected with
the use of language processor.</p>
      <p>Stage 1. The system for English and Russian
morphological analysis - for transformation of words
into normal form. Simplistic analysis of sentences for
discovery of definitions on keywords.</p>
      <p>Stage 2. The component for analysis of sentences with
selection of often met relevant word-combinations.
Stage 3. Means for establishment of relations between
relevant objects that form the clauses.</p>
      <p>Stage 4. Extension of the notion "meaningful
components".</p>
      <p>Not only words and word-combinations are allowed,
but also objects described in documents: people,
addresses, organizations, etc.</p>
      <p>Stage 5.Incorporation of the XML-based semantic
presentations into the semantic navigator. In the XML
file a meaningful portrait of a document (the semantic
network structure) is represented comprising all objects
and connections, revealed by the Semantix text
processor. In connection with this the organization of
XML files has the definite scientific value as the means
for presentation of the semantic structure of sentences
and texts. The transformation of the semantic network
into the XML file is ensured with the aid of the reverse
linguistic processor. In this case the fragments which
present objects, relations, actions and sentences in the
semantic network structure are mapped onto the
appropriate components of the XML file which will
also contain objects, relations, actions and sentences.</p>
      <p>
        The basic task of the LP use consists in operation as
a separate module within the framework of the
integrated systems of information collection and
processing. The exchange is conducted through XML
files [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ]. For that end a reverse LP was developed,
which constructs XML files on the basis of meaningful
portraits.
      </p>
      <p>Thus, the input for the linguistic processor (LP) is a
natural language text, and the output is an XML- file,
where all chosen objects and connections with the
indication of sources are represented. This LP named
Semantix is provided in the form of an SDK- module. It
works under WINDOWS, but it can be recompiled for
the work under LINUX.</p>
      <p>The Semantix Processor is an independent module
and it can be used without the mentioned systems for
the standard tasks of analytical services. There are
means of tuning to the objects of other types - due to the
linguistic knowledge or the dictionaries.</p>
      <p>Let us give some explanations. Each object has the
following structure:
&lt;OBJECT ID="7" TYPE="Organization"&gt;
&lt;ARG CONST="Headquarters /&gt;
&lt;ARG CONST="Residence" /&gt;
&lt;SOURCE&gt; Headquarters residence of the opposing
group&lt;/SOURCE&gt;
&lt;/OBJECT&gt;
where ID="7" – is an identification of an object, the
TYPE="Organization" is its type. The text component
corresponding to the object is also given. Objects
relations and their participation in the actions are given
through the REF=... references. For example, with the
help of the following construction
&lt;ACTION ID="15" TYPE="Blow"&gt;
&lt;ARG CONST="At" /&gt;
&lt;ARG REF="7" /&gt;
&lt;/ACTION&gt;</p>
      <p>where the sentence "one of the blows struck the
headquarters of the oppositional group" is represented.
For each object or action the reference to the sentence is
given. The Semantix processor uses sufficiently
universal constructions of XML- file: one object
(through the reference) can include another object.
Properties are given as arguments. If necessary the type
of attribute is indicated.</p>
      <sec id="sec-10-1">
        <title>For example, in the statement</title>
        <p>&lt;ATTR TYPE="YEAR" VALUE="2003"/&gt;
the year is indicated, etc. An XML file has a
complete set of information items necessary for the use
in different integrated systems.</p>
      </sec>
      <sec id="sec-10-2">
        <title>An example of XML file is given in Figure 3.</title>
      </sec>
    </sec>
    <sec id="sec-11">
      <title>8 Semantic-Focused Systems</title>
      <p>
        The development of concepts of on-line encyclopedia
results in more general systems providing discovery of
semantically meaningful information from documents,
and building on this base an information-reference
system [
        <xref ref-type="bibr" rid="ref1 ref4 ref5 ref6">1, 4-6</xref>
        ]. The method of tuning - introduction
into the system of a new template with the tying of its
positions to the components of natural language, or a
change in the existing templates and corresponding
linguistic knowledge. At present this system is created
on the basis of logical-analytical crime detection system
ANALYST, and the linguistic processor Semantix
using the knowledge base and the semantics- oriented
linguistic processor for the tasks of the automatic
formalization of text information, answer to the queries
in free form, etc. [
        <xref ref-type="bibr" rid="ref4 ref5 ref6">4-6</xref>
        ].
      </p>
      <p>More than 40 different types of objects are
supported by the Semantix processor. The subject areas
represented in the text documents are as follows.
Documents about terrorism in the Russian language.
The analysis of the documents, in which the discussion
deals with the terrorist acts and the groups. This feature
supports the extraction of 40 types of objects, their
connections and the degree of participation in the
criminal actions. Documents about terrorists in the
English language. The objects and links include persons
(their family name, name, patronymic – FNP), posts,
organizations, terrorist groups, instruments of crime,
time and place of events and so forth, and also
connection with and participation in the actions.
 Summaries of incidents. Is ensured the extraction
of figurants, their connections, organizations, dates,
documents, numbers of bank accounts, details of
weapons, etc. with the indication of their participation
in particular criminal actions.
 Accusatory conclusions, information about the
criminal cases. Objects are identified along the entire
field of text. Their connections and criminal actions are
revealed.
 Government communications, media issues.
Persons, dates, organizations, positions and other
significant information and also connections and
participation in the actions are selected.
 Autobiographies in the Russian and English
languages. From the resumes all attributes of people,
periods of time and place of their work, studies,
language proficiency and so forth are extracted.
 Autobiographies in the English. From the English
language resumes are all attributes of people, periods of
time and place of their work, studies, language
proficiency and so forth are extracted.
 Documents of media issues in English. From the
English language texts the persons mentioned in media
issues, positions, organizations, dates, terrorist and
antiterrorist groups, weapons, events, their time and place,
different connections and other features are extracted.</p>
      <p>In the processors of the Semantix, Lingua-Master,
“CrТmТnal” sвstems up to 40 tвpes oП objeМts are
extracted with high accuracy and minimum noise. For
example, the system "Criminal" was verified on about
500 thousand incidents from the summaries of Moscow
Criminal Police Department, and on the basic objects
showed the unique results: the coefficient of noise, i.e.
excessive words in the objects) is not more than 1-2%
and losses are not more than 1%. The Semantix
Processor was fixed on a smaller quantity of documents
dealing with the terrorist activity, and therefore there
can be more noise and losses in it. But this can be
quickly fixed. The fact is that to consider everything
which can be encountered in the NL texts is impossible.</p>
      <p>Therefore, in the first place, the representative
collections of test documents are extremely important,
and in the second place, the means of fixing or tuning of
linguistic processors are as follows: the employment of
hybrid approaches comprising hand-made rules and
statistical means for rapid correction and fine
adjustment of linguistic knowledge. In our systems
there is an entire complex of such means which ensure
rapid tuning to the applications (including the
introduction of new objects and connections) taking into
account the demands of customers.</p>
      <p>Such systems have much in common with the
system of electronic encyclopedia construction. The
significant information corresponds to the names of the
articles of the encyclopedia. Templates are the variety
of schemes, on which are constructed the articles of the
encyclopedia. The layout of the material in accordance
with the scheme is required, as well as taxonomic
formation of hyper-references.</p>
      <p>A backbone instrument for semantic categorization
is the employment of hierarchy. Hierarchy is a form of
organizational structure in which each unit has one and
only one "parent" unit, except the "top" unit, which has
none.</p>
      <p>A Polyhierarchy (multi-hierarchy) is like a
hierarchy, but nodes can have multiple parents. In
mathematical terms, polyhierarchy is represented by a
directed acyclic graph, or a partially ordered set. In
terms of object-oriented methodology, it can be viewed
as class hierarchy with multiple inheritance.</p>
      <p>Directory structure is a particular case of
hierarchical structure (that is more general concept).
The main difference between hierarchical and directory
structure is different naming convention for categories.</p>
      <p>The category names in directory structure can be full
or short (local). The full category names in a directory
usually are equal to their paths from Top category. A
directory contained inside another directory is called a
subdirectory of that directory. Subdirectories are
specified by concatenating the subdirectory short name
to the name of the directory above it in the hierarchy.
Together, the directories form a hierarchy, or tree
structure.</p>
      <p>Keywen Category Structure is a polyhierarchy
(multi-hierarchy) that contains one preferred (primary)
hierarchy (tree) which contains all nodes.</p>
      <p>The method for generating hierarchical categories
from collection of related terms contains the following
steps:
huge collection
of related terms is
(a) A
accumulated;</p>
      <p>(b) Information about relationships of any term is
communicated to users (and agents);</p>
      <p>(c) Users select multiple parent categories for each
term among its relatives;</p>
      <p>(d) Many parent-child relationships are accumulated
and create direct graph; and</p>
      <p>(e) Variety of hierarchical structures is constructed
from combined direct graphs of different users.</p>
      <p>The last step (e) contains sub steps of:
(e1) Direct graphs of different users are combined
together according to user contribution ranks so that
better ranked users have the priority in the selection of
parents for particular term; and</p>
      <p>(e2) Any cycles between nodes in the graph are
eliminated.</p>
      <p>Categories are indicated in the very beginning of an
article; one glance at the category will be sufficient to
determine the field of the article, since all categories
will contain popular terms.</p>
      <p>For example, in the beginning of an article on
Mesopotamia, the category "SOCIETY &gt; HISTORY &gt;
HISTORICAL ERAS &gt; PREHISTORY &gt; IRON AGE
&gt; MESOPOTAMIA" will be indicated.</p>
      <p>EЯen ТП аe Нo not knoа tСe аorН “MESOPOTAMIA”,
the easily understandable words "SOCIETY &gt;
HISTORY" will clearly indicate the field.</p>
      <p>Categories are located in the beginning of an article;
since all categories contain most popular terms, the first
glance at the category will make the field of the article
clear. All category terms correspond to the titles of the
articles, which makes the direction of transition, when
mouse-clicking any term within the category,
selfexplanatory.</p>
      <p>Category String is the line that contains the full
name of category, which consists of several terms, such
as</p>
      <p>"THINKING &gt; NONVERBAL THINKING &gt;
BIGPICTURE THINKING".</p>
      <p>All terms included into the Category String, are located
in hierarchical order, which makes the internal structure
of the category easier to understand and more logical.
Every category (as full path to category) in Keywen
Category Structure is unique.</p>
      <p>Keywen Category Structure contains 17 top-level
categories.
3.1 ANIMALS &gt; SEA_ANIMALS &gt; WHALES
3.2 ARTS &gt; FILM &gt; ANIMATION &gt; ANIME
3.3 BUSINESS &gt; BUSINESS_ECONOMICS
3.4 COMPUTATION &gt; INTERNET &gt; INTERNET_HISTORY &gt;
ARPANET
3.5 GAMES &gt; BOARD_GAMES &gt; KINGS_CRIBBAGE
3.6 HEALTH &gt; MEDICINE &gt; HEALTHCARE &gt; THERAPY &gt;
ENERGY_THERAPIES &gt; REIKI
3.7 HOME &gt; COOKING &gt; FRUIT_JUICE &gt; LEMONADE
3.8 IDEAS &gt; BOOKS
3.9 MINERALS &gt; CRYSTALS &gt; ZIRCON
3.10 PEOPLE &gt; POETS
3.11 PLANTS &gt; TREES
3.12 RECREATION &gt; TRAVEL &gt; TOURISM
3.13 REFERENCE &gt; REFERENCE_WORKS &gt; ATLASES &gt;
CARTOGRAPHY &gt; WEB_MAPPING
3.14 SCIENCE &gt; NATURAL_SCIENCES &gt; SPACE_SCIENCE &gt;
SOLAR_SYSTEM &gt; NEPTUNE
3.15 SOCIETY &gt; HISTORY &gt; HISTORICAL_ERAS &gt;
PREHISTORY &gt; IRON_AGE &gt; MESOPOTAMIA
3.16 THINKING &gt; NONVERBAL_THINKING &gt;
BIGPICTURE_THINKING
3.17 WORLD &gt; AFRICA &gt; MIDDLE_EAST &gt; NORTH_AFRICA
&gt; EGYPT</p>
    </sec>
    <sec id="sec-12">
      <title>9 Conclusions</title>
      <p>Thus by semantic navigation we mean semantic
analysis and search for the relevant semantic
information in natural language texts in the Web.
Semantic analysis consists in assigning a semantic
structure to natural language input. Semantic structure
is obtained via the semantic categorization and
establishment of semantic relations between concepts
presented in natural language texts. Association is the
dominant type of semantic relations supported by
Keywen and the Navigator under development.
Synonyms, taxonomies and other types of paradigmatic
semantic relations are established within particular
contexts and are viewed as particular cases of the
association relation. Hence we employ the semantic
impacts of context and co-occurrence which play the
decisive role in automatic categorization.</p>
      <p>Further development includes the detailed
structuring of the Keywen knowledge base with the
employment of the Semantix linguistic processor and
logical processing features, construction of the
encyclopedic articles from definitions and key words
automatically extracted from Internet, establishment of
hierarchies / category trees on the basis of key word
family trees by assigning a dominant category,
semiautomatic correction of the category tree, manual and
semi-automatic correction of definitions, manual and
semi-automatic correction of articles by the methods of
digital voting and crowdsourcing. The Keywen
technology can be used for terminological data bases
creation according to the International Standard ISO
12620: 2009.</p>
      <p>The approach taken combines the methods of the
rule-based paradigm and machine learning, thus
providing a hybrid platform for design and development
of the Internet Semantic Navigator.
,
,
,
.</p>
      <p>.</p>
      <p>.</p>
      <p>,
,
,</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>Kuznetsov</given-names>
            <surname>Igor. Semantic Representations</surname>
          </string-name>
          . Moscow: Science,
          <year>1986</year>
          . 294 p.
          <article-title>(in Russian)</article-title>
          ..
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          <article-title>[2] Web site for the Keywen encyclopedia of keywords: www</article-title>
          .keywen.com
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>Salton</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          <year>1989</year>
          .
          <article-title>Automatic text processing: The transformation, analysis, and retrieval of information by computer</article-title>
          . New York: AddisonWesley.
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <surname>Kuznetsov</surname>
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Charnine</surname>
            <given-names>M</given-names>
          </string-name>
          .
          <article-title>Semantic-Oriented System For Factual Search With the Interface in Russian</article-title>
          and English // Systems and Facilities of Informatics. Moscow: Science,
          <year>1995</year>
          , V 7.
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <surname>Kuznetsov</surname>
            <given-names>I.P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Efimov</surname>
            <given-names>D.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kozerenko</surname>
            <given-names>E.B.</given-names>
          </string-name>
          <article-title>Tools for Tuning the Semantix Processor to Application Areas //</article-title>
          <source>Proceedings of ICAI'09</source>
          ,
          <string-name>
            <surname>Vol. I. WORLDCOMP</surname>
          </string-name>
          '
          <volume>09</volume>
          ,
          <string-name>
            <surname>July</surname>
            <given-names>13</given-names>
          </string-name>
          <source>-16</source>
          ,
          <year>2009</year>
          ,
          <string-name>
            <given-names>Las</given-names>
            <surname>Vegas</surname>
          </string-name>
          , Nevada, USA. - CRSEA Press, USA,
          <year>2009</year>
          . P.
          <volume>467</volume>
          -
          <fpage>472</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <surname>Kuznetsov</surname>
            <given-names>I.P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kozerenko</surname>
            <given-names>E.B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kuznetsov</surname>
            <given-names>K.I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Timonina</surname>
            <given-names>N.O.</given-names>
          </string-name>
          <article-title>Intelligent System for Entities Extraction (ISEE) from</article-title>
          <source>Natural Language Texts // Proceedings of the International Workshop on Conceptual Structures for Extracting Natural Language Semantics - Sense'09</source>
          ,
          <string-name>
            <surname>Uta</surname>
            <given-names>Priss</given-names>
          </string-name>
          , Galia Angelova (Eds.),
          <source>at the 17 International Conference on Conceptual Structures (ICCS'09)</source>
          , University Higher School of Economics, Moscow, Russia,
          <year>2009</year>
          . P.
          <volume>17</volume>
          -
          <fpage>25</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <surname>Han</surname>
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pei</surname>
            <given-names>Y.</given-names>
          </string-name>
          <string-name>
            <surname>Yin</surname>
          </string-name>
          , and
          <string-name>
            <surname>Mao R. Mining Frequent Patterns without Candidate Generation: A Frequent-Pattern Tree</surname>
            <given-names>ApproaМС</given-names>
          </string-name>
          ,” // Data MТnТnР and Knowledge Discovery,
          <volume>8</volume>
          (
          <issue>1</issue>
          ),
          <year>2004</year>
          . P.
          <volume>53</volume>
          -
          <fpage>87</fpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>FASTUS</given-names>
            <surname>:</surname>
          </string-name>
          <article-title>a Cascaded Finite-State Trasducerfor Extracting Information from Natural-Language Text</article-title>
          . // AIC, SRI International. Menlo Park. California,
          <year>1996</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <surname>Cunningham</surname>
            <given-names>H.</given-names>
          </string-name>
          <string-name>
            <surname>Automatic</surname>
          </string-name>
          Information Extraction // Encyclopedia of Language and Linguistics, 2cnd ed. Elsevier,
          <year>2005</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Dobrov</surname>
            <given-names>B.V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Lukashevich</surname>
            <given-names>N.V.</given-names>
          </string-name>
          <article-title>Ontologies for natural language processing: Description of concepts</article-title>
          and
          <source>lexical senses // Computational Linguistics and Intelligent Technologies: Proceedings of the International Conference DТaloР'06</source>
          ,
          <string-name>
            <surname>BekasoЯo</surname>
          </string-name>
          , Maв,
          <fpage>31</fpage>
          -June, 4,
          <year>2006</year>
          , P.
          <fpage>138</fpage>
          -
          <lpage>142</lpage>
          ,
          <year>2006</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>Kuznetsov</surname>
            <given-names>I.P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Matskevich</surname>
            <given-names>A.G.</given-names>
          </string-name>
          <article-title>The English Language Version of Automatic Extraction of Meaningful Information from</article-title>
          Natural Language Texts // Proceedings of the Dialog-2005
          <string-name>
            <surname>International Conference</surname>
          </string-name>
          <article-title>"Computational Linguistics and Intelligent Technologies"</article-title>
          , Zvenigorod,
          <year>2005pp</year>
          .
          <fpage>303</fpage>
          -
          <lpage>311</lpage>
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <article-title>Web site for Semantic Web</article-title>
          : http://www.w3.org/standards/semanticweb/
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          [13]
          <string-name>
            <surname>Jackendoff</surname>
            ,
            <given-names>R. Semantic</given-names>
          </string-name>
          <string-name>
            <surname>Structures</surname>
          </string-name>
          . MIT Press, Cambridge, MA, 1990
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          [14]
          <string-name>
            <surname>Gardner</surname>
            ,
            <given-names>J. R.</given-names>
          </string-name>
          and
          <string-name>
            <given-names>Z. L.</given-names>
            <surname>Rendon</surname>
          </string-name>
          ,
          <article-title>XSLT and XPATH: A Guide to XML Transformations</article-title>
          , Prentice Hall,
          <year>2001</year>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>