<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>ICT in Education, Research and Industrial Applications: Integration, Harmonization and Knowledge Transfer</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Preface</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Kherson</institution>
          ,
          <addr-line>Ukraine June, 2013</addr-line>
        </aff>
      </contrib-group>
      <fpage>556</fpage>
      <lpage>597</lpage>
      <kwd-group>
        <kwd>and Industrial Applications</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>ICTERI 2013
Ermolayev, V., Mayr, H. C., Nikitchenko, M., Spivakovskiy, A., Zholtkevych, G.,
Zavileysky, M., Kravtsov, H., Kobets, V. and Peschanenko, V. (Eds.): ICT in
Education, Research and Industrial Applications: Integration, Harmonization and
Knowledge Transfer. Proc. 9th Int. Conf. ICTERI 2013, Kherson, Ukraine, June 19-22, 2013,
CEUR-WS.org, online</p>
      <p>This volume constitutes the refereed proceedings of the 9th International
Conference on ICT in Education, Research, and Industrial Applications, held in Kherson,
Ukraine, in June 2013.</p>
      <p>The 49 papers were carefully reviewed and selected from 124 submissions. The
volume opens with the contributions of the invited speakers. Further, the part of the
volume containing the papers of the main ICTERI conference is structured in four
topical parts: ICT infrastructures, Integration and Interoperability; Machine
Intelligence, Knowledge Engineering and Management for ICT; Model-based software
system development; and Methodological and Didactical Aspects of Teaching ICT
and Using ICT in Education. This part of the volume is concluded by the two papers
describing the tutorials presented at the conference. The final part of the volume
comprises the selected contributions of the three workshops co-located with ICTERI
2013, namely: the 1st International Workshop on Methods and Resources of Distance
Learning (MRDL 2013); the 2nd International Workshop on Information
Technologies in Economic Research (ITER 2013); and the 2nd International Workshop on
Algebraic, Logical, and Algorithmic Methods of System Modeling, Specification and
Verification (SMSV 2013).</p>
      <p>Copyright © 2013 for the individual papers by the papers’ authors.
Copying permitted only for private and academic purposes. This
volume is published and copyrighted by its editors.
It is our pleasure to present you the proceedings of ICTERI 2013, the ninth edition of
the International Conference on Information and Communication Technologies in
Education, Research, and Industrial Applications: Integration, Harmonization, and
Knowledge Transfer, held at Kherson, Ukraine on June 19-22, 2013. ICTERI is
concerned with interrelated topics from information and communication technology
(ICT) infrastructures to teaching these technologies or using those in education or
industry. Those aspects of ICT research, development, technology transfer, and use in
real world cases are vibrant for both the academic and industrial communities.</p>
      <p>The conference scope was outlined as a constellation of the following themes:
 ICT infrastructures, integration and interoperability
 Machine Intelligence, knowledge engineering, and knowledge management
for ICT
 Cooperation between academia and industry in ICT
 Model-based software system development
 Methodological and didactical aspects of teaching ICT and using ICT in education</p>
      <p>A visit to Google Analytics proves the broad and continuously increasing interest
in the ICTERI themes. Indeed, between November 15, 2012 and May 15, 2013 we
have received circa 4 400 visits to the conference web site, http://icteri.org/, from 110
countries (568 cities). These numbers are 1.5 – 2 times higher than those observed in
the similar period for ICTERI 2012.</p>
      <p>ICTERI 2013 continues the tradition of hosting co-located focused events under its
umbrella. In the complement to the main conference this year, the program offered the
three co-located workshops, two tutorials, and IT talks panel. The main conference
program has been composed of the top-rated submissions evenly covering all the
themes of ICTERI scope.</p>
      <p>The workshops formed the corolla around the main ICTERI conference by
focusing on particular sub-fields relevant to the conference theme. In particular:
 The 1st International Workshop on Methods and Resources of Distance Learning
(MRDL 2013) dealt mainly with the methodological and didactical aspects of
teaching ICT and using ICT in education
 The scope of the 2nd International Workshop on Information Technologies in
Economic Research (ITER 2013) was more within the topic of cooperation between
academia and industry
 2nd International Workshop on Algebraic, Logical, and Algorithmic Methods of
System Modeling, Specification and Verification (SMSV 2013) focused on
modelbased software system development</p>
      <p>The IT Talks panel was the venue for the invited industrial speakers who wish to
present their cutting edge ICT achievements.</p>
      <p>This year we were also accepted the two focused short tutorials to the program: on
ontology alignment and the industrial applications of this technology; and on the time
model and Clock Constraint Specification Language for the UML profile used in
modeling and analysis of real-time and embedded systems.</p>
      <p>Overall ICTERI attracted a substantial number of submissions – a total of 124
comprising the main conference and workshops. Out of the 60 paper submissions to
the main conference we have accepted 22 high quality and most interesting papers to
be presented at the conference and published in our proceedings. The acceptance rate
was therefore 36.7 percent. Our three workshops received overall 64 submissions,
from which 27 were accepted by their organizers and included in the second part of
this volume. Those selected publications are preceded by the contributions of our
invited speakers. The talk by our keynote speaker Wolf-Ekkehard Matzke expressed
his industrial views on the knowledge-based bio-economy and the “Green
TripleHelix” of biotechnology, synthetic biology, and ICT. The invited talk by Gary L. Pratt
was focused on a movement of higher education institutions to forming consortiums
for creating a position of strength facing contemporary economic challenges. The
invited talk by Alexander A. Letichevsky presented a general theory of interaction
and cognitive architectures based on this theory.</p>
      <p>The conference would not have been possible without the support of many people.
First of all we would like to thank all the authors who submitted papers to ICTERI
2013 and thus demonstrated their interest in the research problems within our scope.
We are also very grateful to the members of our Program Committee for providing
timely and thorough reviews and also for been cooperative in doing additional review
work. We would like also to thank the local organizers of the conference whose
devotion and efficiency made this instance of ICTERI a very comfortable and effective
scientific forum. Finally a special acknowledgement is given to the support by our
editorial assistant Olga Tatarintseva who invested a considerable effort in checking
and proofing the final versions of our papers.</p>
      <p>June, 2013
Vadim Ermolayev
Heinrich C. Mayr
Mykola Nikitchenko
Aleksander Spivakovskiy
Grygoriy Zholtkevych
Mikhail Zavileysky
Hennadiy Kravtsov
Vitaliy Kobets</p>
      <p>Vladimir Peschanenko</p>
    </sec>
    <sec id="sec-2">
      <title>Organization</title>
      <sec id="sec-2-1">
        <title>Organizers</title>
        <p>Ministry of Education and Science of Ukraine
Kherson State University, Ukraine
Alpen-Adria-Universität Klagenfurt, Austria
Zaporizhzhya National University, Ukraine
Institute of Information Technology and Teaching Resources, Ukraine
V. N. Karazin Kharkiv National University, Ukraine
Taras Shevchenko National University of Kyiv, Ukraine
DataArt Solutions Inc.</p>
      </sec>
      <sec id="sec-2-2">
        <title>General Chair</title>
        <p>Aleksander Spivakovsky, Kherson State University, Ukraine</p>
      </sec>
      <sec id="sec-2-3">
        <title>Steering Committee</title>
        <p>Vadim Ermolayev, Zaporizhzhya National University, Ukraine
Heinrich C. Mayr, Alpen-Adria-Universät Klagenfurt, Austria
Natalia Morse, National University of Life and Environmental Sciences, Ukraine
Mykola Nikitchenko, Taras Shevchenko National University of Kyiv, Ukraine
Aleksander Spivakovsky, Kherson State University, Ukraine
Mikhail Zavileysky, DataArt, Russian Federation</p>
        <p>Grygoriy Zholtkevych, V.N.Karazin Kharkiv National University, Ukraine</p>
      </sec>
      <sec id="sec-2-4">
        <title>Program Co-chairs</title>
      </sec>
      <sec id="sec-2-5">
        <title>Workshops Chair</title>
      </sec>
      <sec id="sec-2-6">
        <title>Tutorials Chair</title>
        <p>Mykola Nikitchenko, Taras Shevchenko National University of Kyiv, Ukraine
Grygoriy Zholtkevych, V.N.Karazin Kharkiv National University, Ukraine</p>
      </sec>
      <sec id="sec-2-7">
        <title>IT Talks Co-chairs</title>
        <p>Aleksander Spivakovsky, Kherson State University, Ukraine
Mikhail Zavileysky, DataArt, Russian Federation</p>
      </sec>
      <sec id="sec-2-8">
        <title>Program Committee</title>
        <p>Vladimir A. Shekhovtsov, Alpen-Adria-Universität Klagenfurt, Austria
Mikhail Simonov, Istituto Superiore Mario Boella, Italy
Marcus Spies, Ludwig-Maximilians-Universität München, Germany
Aleksander Spivakovsky, Kherson State University, Ukraine
Martin Strecker, IRIT, Universite Paul Sabatier, France
Olga Tatarintseva, Zaporizhzhya National University, Ukraine
Vagan Terziyan, University of Jyväskylä, Finland
Nikolay Tkachuk, National Technical University "Kharkiv Polytechnic Institute”, Ukraine
Leo Van Moergestel, Utrecht University of Applied Sciences, Netherlands
Maryna Vladymyrova, V. N. Karazin Kharkov National University, Ukraine
Paul Warren, Knowledge Media Institute, the Open University, United Kingdom
Iryna Zaretska, V. N. Karazin Kharkov National University, Ukraine
Mikhail Zavileysky, DataArt Solutions Inc., Russian Federation</p>
        <p>Grygoriy Zholtkevych, V. N. Karazin Kharkov National University, Ukraine</p>
      </sec>
      <sec id="sec-2-9">
        <title>Additional Reviewers</title>
        <p>Fahdi Al Machot, Alpen-Adria-Universität Klagenfurt, Austria
Antonio Gonzalez-Pardo, Universidad Autonoma de Madrid, Spain
Alexey Vekschin, National Technical University "Kharkiv Polytechnic Institute”, Ukraine</p>
      </sec>
      <sec id="sec-2-10">
        <title>Individuals</title>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>Sponsors</title>
      <sec id="sec-3-1">
        <title>Organizations and Companies</title>
        <p>DataArt (http://dataart.com/) develops custom applications,
helping clients optimize time-to-market and save costs
Kherson State University (http://www.ksu.ks.ua/) is a
multidisciplinary scientific, educational, and cultural center in the
south of Ukraine
Zaporizhzhya National University (http://www.znu.edu.ua/)
is a renowned educational and research center of Ukraine that
offers a classically balanced diversity of high quality
academic curricula and many opportunities to build your
scientific carrier
Aleksandr Spivakovsky is the chair of the Department of
Informatics and the first vice-rector of Kherson State
University
Dmitriy Shchedrolosev is the head of DataArt’s R&amp;D Center
at Kherson
Preface ..........................................................................................................................I
1.5 ICTERI Tutorials ............................................................................................. 288
Binary Quasi Equidistant and Reflected Codes in Mixed Numeration Systems.... 311
Mechanism Design for Foreign Producers of Unique Homogeneity Product........ 329
Features of National Welfare Innovative Potential Parametric Indication
Information-Analytical Tools System in the Globalization Trends’ Context ........ 339
Matrix Analogues of the Diffie-Hellman Protocol ................................................ 352
Are Securities Secure: Study of the Influence of the International
Debt Securities on the Economic Growth.............................................................. 360
How to Make High-tech Industry Highly Developed? Effective Model
of National R&amp;D Investment Policy...................................................................... 366
Author Index ........................................................................................................... 595</p>
        <p>Invited Contributions</p>
        <sec id="sec-3-1-1">
          <title>The Knowledge-Based Bio-Economy and the “Green</title>
        </sec>
        <sec id="sec-3-1-2">
          <title>Triple-Helix” of Biotechnology, Synthetic Biology and ICT</title>
          <p>Wolf-Ekkehard Matzke
MINRES Technologises GmbH, Neubiberg, Germany
Abstract. Over the last decades economies around the globe have transformed
into a knowledge-based economy (KBE). Information and Communication
Technology (ICT) has served as the principal enabling technology for this
transformation. Now biology becomes another major pillar – producing a
knowledge-based bio-economy (KBBE). The challenges faced by biotechnology push
the requirements for ICT in many ways to the extreme and far beyond its basic
utility function. In particular, it is valid for synthetic biology which aims to
break ground on the rational design and construction of artificial biological
systems with ICT as its backbone for bio-design automation (BDA). This could be
best illustrated using a metaphor of a “green triple-helix”, where “green” stands
for environmental consciousness and “triple-helix” visualizes the
interdependency of biotechnology, synthetic biology, and ICT as the helical strands.
The talk will explore this inter-dependency in dynamics. High level ICT
requirements will be identified and discussed along the dimensions of education,
research and industry with the emphasis on synthetic biology and BDA. The
guidelines for the architecture and implementation of an open BDA platform
will be presented so that interested ICT researchers and practitioners will better
understand the biology-specific ICT challenges of the KBBE.</p>
        </sec>
        <sec id="sec-3-1-3">
          <title>A Movement of Higher Education Institutions to Consortiums of Institutions Banding Together to Create a Position of Strength</title>
          <p>Eastern Washington University, 202 Huston Hall, Cheney, Washington 99004, USA</p>
          <p>Gary L. Pratt
Abstract. Colleges and universities compete for students, faculty, and business,
industry, and research partnerships with quality programs, strong faculty,
research opportunities, affordable cost, and high student success factors. Yet, at
the infrastructure level, most of these institutions provide many similar
information technology services and support. On top of this, many of these institutions
struggle to provide this quality infrastructure because of a variety of factors,
including: shrinking budgets, minimal strategic planning, and a lack of
institutional vision of information technology as a strategic asset. This presentation
will showcase best practice examples of how higher education institutions can
band together, to create strong consortium relationships that can help all
partners in this relationship move forward as a strong force. Examples will include
actual successes experience by the Kentucky Council on Postsecondary
Educations Distance Learning Advisory Committee (DLAC), the Washington
Legislative Technology Transformation Taskforce (TTT), and the Washington
Higher Education Technology Consortium (WHETC).These successes range
from statewide strategic planning efforts, to significant consortial purchasing
contracts, to collaborative technology systems, services, and training
opportunities. This presentation will show that institutions can be stronger working
together than working individually.</p>
          <p>Keywords. University consortium, best practice, competition, infrastructure,
information technology, strategic asset, strategic planning, collaborative
technology system
General Theory of Interaction and Cognitive
Architectures</p>
          <p>Alexander Letichevsky
Glushkov Institute of Cybernetics, Academy of Sciences of Ukraine
40 Glushkova ave., 03187, Kyiv, Ukraine</p>
          <p>let@cyfra.net
Abstract. The challenge of creating a real-life computational
equivalent of the human mind is now attracting the attention of many scienti c
groups from di erent areas of cybernetics and Arti cial Intelligence such
as computational neuroscience, cognitive science, biologically inspired
cognitive architectures etc. The paper presents a new cognitive
architecture based on insertion modeling, one of the paradigms of a general
theory of interaction, and a basis for multiagent system development.
Insertion cognitive architecture is represented as a multilevel insertion
machine which realizes itself as a high level insertion environment. It has
a center to evaluate the success of its behavior which is a special type
agent that can observe the interaction of a system with external
environment. The main goal of a system is achieving maximum success repeated.
As an agent this machine is inserted into its external environment and
has the means to interact with it. The internal environment of intelligent
cognitive agent creates and develops its own model and the model of
external environment. If the external environment contains other agents,
they can be modeled by internal environment which creates
corresponding machines and interprets those machines using corresponding drivers,
comparing the behaviors of models and external agents. Insertion
architecture is now under development on the base of Insertion modeling
system, developed in Glushkov Institute of Cybernetics.
Key terms. AgentBasedSystem, DistributedArti cialIntelligence,
Reasoning, FormalMethod, Simulation
1</p>
          <p>
            Introduction
General theory of interaction is a theory of information interaction in complex
distributed multi-agent systems. It has a long history. Contemporary part of
this history can be considered as starting from neuro networks of
McCullochPitts [
            <xref ref-type="bibr" rid="ref37">23</xref>
            ]. The model of neuro nets caused the appearance of abstract automata
theory, a theory which helps study the behavior and interaction of evolving
systems independently of their structure. The Kleene-Glushkov algebra [
            <xref ref-type="bibr" rid="ref13 ref21 ref27 ref7">13, 7</xref>
            ]
is the main tool for the description of the behaviors of nite state systems.
Automata theory originally concentrated on the study of analyses and synthesis
problems, generalization of nite state automata and complexity. Interaction in
explicit form appeared only in 70s as a general theory of interacting information
processes. It includes the CCS (Calculus of Communicated Processes) [24, 25]
and the -calculus of R. Milner [26], CSP (Communicated Sequential Processes)
of T. Hoare [
            <xref ref-type="bibr" rid="ref10 ref24">10</xref>
            ], ACP (Algebra of Communicated Processes) [
            <xref ref-type="bibr" rid="ref17 ref3">3</xref>
            ] and many other
various branches of these basic theories. Now all these calculi and algebras are
the basis for modern research in this area. Fairly complete survey of the classical
process theory is presented in the Handbook of Process Algebras [
            <xref ref-type="bibr" rid="ref18 ref4">4</xref>
            ], published
in 2001.
          </p>
          <p>
            Insertion modeling is a trend that is developing over the last decade as an
approach to a general theory of interaction of agents and environments in
complex distributed multi-agent systems. The rst works in this direction have been
published in the middle of 90s [
            <xref ref-type="bibr" rid="ref20 ref29 ref30 ref6">6, 15, 16</xref>
            ]. In these studies, a model of
interaction between agents and environments based on the notion of insertion function
and the algebra of behaviors (similar to some kind of process algebra) has been
proposed. The paradigm shift from computing to interaction was extensively
discussed in computer science that time, and our work was in some sense a response
to this trend. But the real roots of the insertion model should be sought even
earlier, in a model of interacting of control and operational automata, proposed
by V. Glushkov back in the 60s [
            <xref ref-type="bibr" rid="ref22 ref23 ref8 ref9">8, 9</xref>
            ] to describe the structure of computers.
In the 70s the algebraic abstraction of this model were studied in the theory of
discrete processors and provided a number of important results on the problem
of equivalence of programs, their equivalent transformations and optimization.
Macroconveyor models of parallel computing, which were investigated in 80s
years [
            <xref ref-type="bibr" rid="ref11 ref25">11</xref>
            ], even more close to the model of interaction of agents and
environments. In these models, the processes corresponding to the parallel processors
can be considered as agents that interact in an environment of distributed data
structures.
          </p>
          <p>
            In recent years, insertion modeling has been applied to the development
of systems for the veri cation of requirements and speci cations of distributed
interacting systems [2, 12, 19{21]. The system VRS, developed in order from
Motorola, has been successfully applied to verify the requirements and speci cations
in the eld of telecommunication systems, embedded systems, and real-time
systems. A new insertion modeling system IMS [
            <xref ref-type="bibr" rid="ref31">17</xref>
            ], which is under development
in the Glushkov Institute of Cybernetics of the National Academy of Sciences
of Ukraine, is intended to extend the area of insertion modeling applications.
We found many common features of the tools used in software development area
based on formal methods and techniques used in biologically inspired cognitive
architectures. This gives us hope to introduce some new ideas to the development
of this subject domain.
          </p>
          <p>
            This paper presents the main principals of insertion modeling and the
conception of cognitive architecture based on insertion modeling. To understand the
formal part of the paper reader must be familiar with the concepts of labeled
transition system, bisimilarity and basic notions of general process theory. The
mathematical foundation of insertion modeling is presented in [
            <xref ref-type="bibr" rid="ref32">18</xref>
            ].
2
          </p>
          <p>The Basic Principals
Insertion modeling deals with the construction of models and study the
interaction of agents and environments in complex distributed multi-agent systems.
Informally, the basic principles of the paradigm of insertion modeling can be
formulated as follows.
1. The world is a hierarchy of environments and agents inserted into them.
2. Environments and agents are entities evolving in time.
3. Insertion of agent into environment changes the behavior of environment and
produces new environment which is in general ready for the insertion of new
agents.
4. Environments as agents can be inserted into higher level environment.
5. New agents can be inserted from external environment as well as from
internal agents (environments).
6. Agents and environments can model another agents and environments on
the di erent levels of abstraction.</p>
          <p>All these principles can be formalized in terms of transition systems, behavior
algebras, and insertion functions. This formalization can be used as high level
abstractions of biological entities needed for computer modeling of human mind.</p>
          <p>The rst and the second principals are commonly used in information
modelling of di erent kinds of systems, for example as in object oriented or agent
programming. They are also resembling to M. Minsky's approach of the society
of mind [27].</p>
          <p>The third principal is clear intuitively, but has a special re nement in
insertion modelling. We treat agents as transition systems with states considered up
to bisimilarity (or up to behavior, which is the same). The type of an agent is
the set of actions it can perform. The term action we use as a synonim of label
for transitions, and it can denote signals or messages to send, events in which an
agent can participate etc. This is the most general notion of agent which must
be distinguished from more special notions of autonomous or intellectual agents
in AI.</p>
          <p>
            Transition system consists of states and transitions that connect states.
Transitions are labeled by actions (signals, events, instructions, statements etc.).
Transition systems are evolving in time changing their states, and actions are
observable symbolic structures used for communication. We use the well-known
notation s a! s0 to express the fact that transition system can evolve from the
state s to s0 performing action a. Usually transition systems are nondeterministic
and there can be several transitions coming from the same state even labeled by
the same action. If we abstract from the structure of states and concentrate only
on (branching) sequences of observable actions we obtain the state equivalence
called bisimilarity (originated from [28] and [24], exact de nition can be found
in [
            <xref ref-type="bibr" rid="ref32">18</xref>
            ]). Bisimilar states generate the same behavior of transition systems.
          </p>
          <p>Environment by de nition is an agent that possesses the insertion function.
Given the state of environment s and the state of agent u, insertion function
computes the new state of environment which is denoted as s[u]. Note that we
consider states up to bisimilarity and if we have some representation of behaviors,
the behaviors of environment and agent can be used as states. The state s[u]
is a state of environment and we can use insertion function to insert a new
agent v into environment s[u] : (s[u])[v] = s[u; v]. Repeating this construction
we can obtain the state of environment s[u1; u2; : : :] with several agents inserted
into it. Insertion function can be considered as an operator over the states of
environment, and if the states are identi ed with behaviors, then the insertion
of a new agent changes the behavior of environment.</p>
          <p>Environment is an agent with insertion function, so if we forget the
insertion function, then environment can be inserted as agent into a higher level
environment and we can obtain hierarchical structure like</p>
          <p>s[s1[u11; u12; : : :]E1 ; s2[u21; u22; : : :]E2 ; : : :]E
Here notation s[u1; u2; : : :]E explicitly shows the environment E to which the
state s belongs (environment indexes can be omitted if they are known from the
context). This re nes the fourth principle.</p>
          <p>Environment is an agent which can be inserted into external environment
and having agents inserted into this environment. The evolution of agents can
be de ned by the rules for transitions. The rules s[u] a! s[u; v] and s[t[u; v]] a!
s[t[u]; v] can be used for the illustration of the 5-th principal.</p>
          <p>We consider the creating and manipulation of the models of external and
internal environments as the main property of cognitive processes of intellectual
agent. Formalization of this property in terms of insertion modeling supports
the 6-th principal.</p>
          <p>Cognitive architecture will be constructed as a multilevel insertion
environment. Below we shall de ne the main kinds of blocks used for construction of
cognitive architecture. They are local description unites and insertion machines.
3
To represent behaviors of transition systems we use behavior algebras (a kind of
process algebra). Behavior algebra is de ned by the set of actions and the set
of behaviors (processes). It has two operations and termination constants.
Operations are pre xing a:u (a - action, u - behavior) and nondeterministic choice
u + v (u and v - behaviors). Termination constants are successful termination
, deadlock 0, and unde ned behavior ?. It has also approximation relation ,
which is a partial order with minimal element ?, and is used for constructing
a complete algebra with xed point theorem. To de ne in nite behaviors we
use equations in behavior algebra. These equations have the form of recursive
de nitions ui = Fi(u1; u2; : : :); i = 1; 2; : : : and de ne left hand side functions as
the components of a minimal xed point. Left hand sides of these de nitions can
depend on parameters ui(x) = Fi(u; x) of di erent types. In complete behavior
algebra each behavior has a representation (normal form)
u =</p>
          <p>X ai:ui + "i
i2I
which is de ned uniquely (up to commutativity and associativity of
nondeterministic choice), if all ai:ui are di erent ("u is a termination constant).</p>
          <p>The type of environment is de ned by two action sets: the set of environment
actions and the set of agent actions. The last de nes the type of agents which
can be inserted into this environment: if the set of agent actions is included in
the set of agent actions of environment then this agent can be inserted into this
environment. This relation is called compatibility relation between agents and
environments (agent is compatible with environment if it can be inserted into
this environment). Multilevel environment is a family of environments with
distinguished the most external environment. The compatibility relation on the set
of environments de nes a directed graph and we demand for multilevel
environment that the outermost environment would be reachable from any environment
of the family in this graph.</p>
          <p>To de ne the insertion function for some environment it is su cient to de ne
transition relation for all states of environment including states with inserted
agents. The common approach is to de ne behavior by means of rules. The
following is an example of such rule:
s !b s0; u !a u0
s[u] !c s0[u0]</p>
          <p>P (a; b; c)
This rule can be interpreted as follows. Agent in the state u can make a transition
u !a u0. Environment allows this transition if the predicate P (a; b; c) is true. This
rule de nes behavior property of environment in some local neighborhood of the
state s[u]. So such a rule belongs to the class of local description units discussed
in the next section.</p>
          <p>At a given moment of time an agent belongs (is inserted) to only one
environment. But if the type of an agent is compatible with the type of another
environment it can move to this environment. Such a movements can be
described by the following types of rules:
moving from internal to external environment;
u moveup E
E[F [u; v]; w] moveup(F !E!) E[F [v]; u0; w]</p>
          <p>u movedn !F u0
E[F [v]; u; w] movedn(E!F !) E[F [u0; v]; w]
P1(E; F; u; moveup(E))
P2(E; F; u; movedn(F ))
tional testing. Hundreds of components were formally specified and tested with
UniTESK. By the end of the first year of using UniTESK the positive effect appeared
in shorter time of integration of new versions of the distributed system. However, a
serious problem revealed. In the previous UniTESK applications the requirements to
most interfaces were defined by standards and other well-developed documents. But
here the level of components documentation often appeared to be insufficient for
creation of consistent specifications. Recovery of documentation or requirements to
interfaces in the systems of such size becomes almost unsolvable task, which often
makes it impossible to use MBT in corpore. Possible solution of this problem will be
briefly discussed in Conclusion.</p>
          <p>
            The largest example of UniTESK application is the OLVER (Open Linux
VERification) project [
            <xref ref-type="bibr" rid="ref21 ref7">7</xref>
            ] fulfilled in 2005-2007 under support of the Russian Ministry of
Education and Science. The goal of the project was to create formal specifications of
interfaces defined in the Linux Standard Base (LSB) standard or in LSB Core – the
central part of this standard, to be more exact. The LSB Core includes the most
important libraries of OS Linux which implement most of the POSIX standard. The
rigorous description of the LSB standard and the test suite capable of a high-quality
checking of conformance of any Linux library implementation to the requirements of
the standard is a very powerful tool for providing portability of OS Linux applications
from one Linux distribution to another. The portability problem is very critical in the
Linux ecosystem, since several hundreds of very different distributions are available.
The project results are open [
            <xref ref-type="bibr" rid="ref21 ref7">7</xref>
            ]. The contract specifications of more than 1500
interfaces in C were created. Naturally, the CTESK tool was used for modeling and test
generation. In this project, the problems in the standards were also revealed: in LSB
(ISO/IEC 23360) and in The Single UNIX Specification containing the POSIX.1
standard (aka IEEE Std 1003.1, aka ISO/IEC 9945, aka The Open Group Base
Specifications Issue 6) as its significant part. The developed test suite is included into the
package of the certification tests of the international consortium The Linux
Foundation [
            <xref ref-type="bibr" rid="ref13 ref27">13</xref>
            ].
          </p>
          <p>The experience of interface formalization for a large industrial standard and test
suite development for such standard gave many lessons to learn. One of such lessons
is importance of informational and methodological organization of such project. The
amount of documentation and sources, especially with respect to multiple versions
and variants for different hardware platforms, is huge. Besides, the development of
the standard and development of interface implementations involve thousands of
people around the world. It means that the documentation maintenance and availability is
one of the most important concerns of the projects of such scale. On the
organizational and methodical side, we faced the fact that the training of new employees and
the specification and tests quality control require a lot of effort, and the quick
achievement of the required professional level is still impossible. In other words, the
scalability of the MBT projects in the part of increasing the number of specification
and verification experts is one of the most complicated problems preventing MBT
from wide introduction.</p>
          <p>One of the methodical problems is the choice of the abstraction level for the model.
More abstract models or models separated into two-three layers of different
abstraction levels simplify the reuse of the models and tests yielding, however, the bigger
and more complex test system. In the long term, it’s better to have multilayer models,
while in the short term the models close to implementation in the detail level (of
course, if the implementation already exists) are more appropriate. A professional and
experienced verification expert can find the balance between the abstract description
of the behavior, for example, of a file system and specifics and details of the interface
of its particular implementation. UniTESK provides special support for the separation
of abstraction levels. In particular, the specifics of interfaces can be encapsulated in
the mediator-adapter layer. The choice of the balance is determined by the long-tem
plans on using and improvement of the models and the test suite. So, the work of such
kind requires a broad experience and long-term planning skills, which can hardly be
expected from ordinary test engineers.</p>
          <p>
            The results of the OLVER project were used later on in the development of the test
suite for the Russian real-time operating system OS2000/3000 [
            <xref ref-type="bibr" rid="ref14 ref28">14</xref>
            ]. This system
provides two groups of interfaces. The first group meets the requirements of the POSIX
standard, the second one – the requirements of the ARINC-653 international standard
for the embedded and other safety critical systems. The definition of the adapter layer
separating model and implementation representations of the interfaces provided by
the UniTESK architecture significantly simplified the OLVER reuse in this project.
          </p>
          <p>
            Along with the start of the OLVER project, the work on the UniTESK application
to testing of microprocessor designs [
            <xref ref-type="bibr" rid="ref29">15</xref>
            ] has been started. Hardware units being parts
of Russian microprocessors with the MIPS architecture and microprocessors with
VLIM/EPIC elements became the systems under test in this case. The size of typical
units in such microprocessors is several millions of gates. The tools required no
significant modifications for specification and test generation since CTESK was used as
the basis. Technically, binding CTESK to corresponding API of microprocessor
model simulator is not a problem, because most simulators that work with modeling
languages for microprocessors logic (HLD – High Level Design languages), for
example, VHDL or Verilog, provide suitable interface to C programs. Pre-conditions
semantics in contract specifications had to be slightly modified. They now describe
not just the domain of input data, but rather the operation execution readiness
conditions in the given time frame. The same as in the case of protocols modeling, the use
of explicit models of the target device behavior (functionality) along with the
postconditions in the form of predicates appeared to be necessary.
          </p>
          <p>
            Similar to the projects on verification of software systems, one of the main
problems preventing MBT from introduction into practice (as well as many other
verification methods) is the lack of documentation and other descriptions of functional
requirements to components. However, the situation in microprocessors development is
slightly better than in the case of software development, because in this case it is
customary to build system and architectural models of instruction set semantics along
with the HLD models. Elements of these architectural models can be used to fill the
gap in the knowledge on behavior of some microprocessor design units [
            <xref ref-type="bibr" rid="ref30">16</xref>
            ]. It
appears also relatively simple to implement parallel test execution on clusters. Typical
size of the finite-state machine generated during test execution for one microprocessor
unit is millions of nodes and dozens of millions of transitions. The algorithm of FSM
generation and exploration on clusters with up to 200 nodes appeared to require just
10-15% overhead, i.e. scalability coefficient is close to 1.
          </p>
          <p>
            It is important to mention the verification tasks that, on the one hand, could not be
reduced to modeling with contract specifications, and, on the other hand, pushed
forward the development of new MBT methods. In the first place, the task of compiler
testing should be mentioned, as well as the task of testing microprocessor as a whole,
the so-called “core testing”. The both cases are the tasks of system testing, where test
data and test stimuli are submitted to a big “black box” (in our case, these are test
programs submitted to the compiler or loaded into memory of the microprocessor
simulator), and it is interesting to test not just everything, but some specific behavior
modes or specific group of units. In the case of compiler testing, the OTK tool has
been developed that was used for testing of optimizing Intel compilers and Simulink
[
            <xref ref-type="bibr" rid="ref31 ref32">17, 18</xref>
            ]. It allows targeting on specific kinds of optimizations. In the case of
microprocessor design verification, the MicroTESK tool [
            <xref ref-type="bibr" rid="ref33 ref34 ref35">19, 20, 21</xref>
            ] was developed. The
main goal of this tool is checking of various situations appearing in the most
complicated subsystems of memory control: TLB, cache and Memory Management Unit
(MMU) as a whole.
3
          </p>
          <p>Conclusions and Further Work
Let’s start with positive conclusions.</p>
          <p>
            Positive Conclusions on Modern State of Using MBT
 The world experience is confirmed [
            <xref ref-type="bibr" rid="ref36">22</xref>
            ], MBT can be effectively used in industrial
projects, and in comparison with the traditional testing MBT gives a unique
advantage – many defects can be found in requirements, which are often much more
expensive than the defects in implementation
 The achievable level of test coverage is significantly higher than the traditional one
(even in comparison with the “white box” testing). Thus, in the case of using OTK
for testing GCC compiler, the achieved test coverage was 95%, and in the case of
the Intel compiler this level was 75% that was significantly higher than the level
achieved by traditional tests [
            <xref ref-type="bibr" rid="ref32">18</xref>
            ].
 Although the multi-level structure of specifications (several levels of abstraction) is
seldom used in practice, the explicit separation of adapters layer simplifies tests
porting and maintenance and, vise versa, the lack of the corresponding level of
adaptation makes test suite development significantly more complicated, which was
demonstrated in the Microsoft Interoperability Initiative program [
            <xref ref-type="bibr" rid="ref37">23</xref>
            ]
 Online generation of test sequences with the FSM exploration method can be
efficiently parallelized and allows using computational resources of clusters with just
10-15% overhead, at least in the case of microprocessor models testing
 The demand of MBT in the safety critical area increases. This tendency can be
found in standards defining requirements to development processes for safety
critical systems, for example, in DO178C [24] and in Common Criteria [25].
3.2
          </p>
          <p>
            Negative Aspects of the Modern State in the MBT Area
 The main obstacle preventing MBT from wide introduction into practice is the
absence of specifications/models in casual software development. That is, the lack
of specifications is often not only the consequence of insufficient attention to
specification development or the consequence of short resources. The main reason
is often the lack of qualified specialists who are experts in the knowledge domain
and at the same time can create specification/model necessary for test generation.
 If MBT is used in projects that do not involve MDD (Model Driven Development)
approach, then the model development delays the appearance of first tests – this
does not allow obtain tests early in the development. If MBT is used within MDD,
then the problems still remain, because different models required for development
and for testing, in particular, for generation of different artifacts of the test suite. It
is often considered as unacceptable additional cost, while with proper planning
many components of the development models can be reused during test generation
as demonstrated, for example, in M. M. Chupilko paper [
            <xref ref-type="bibr" rid="ref30">16</xref>
            ].
 Bilingual test generation systems like UniTESK and first versions of
SpecExplorer [26], specification notations even close to conventional programming
languages, for example, JML [27] make deployment of such systems difficult.
Bilingual notations require special training of the staff and need permanent and
expensive maintenance. Still note that the modern object-oriented languages already have
advanced means for writing specifications just in the same language [26-31].
3.3
          </p>
          <p>Directions of Further Works
 A variety of modeling paradigms should be used in various project contexts, in
particular, contract specifications, various types of executable models, for example,
finite-state machines, Kripke structures, etc. [32]. It is not obvious that the
transformation of models from one paradigm into another one will bring real benefit.
Each of the model kinds is suitable for analysis of specific aspects of the system
behavior, so we should not expect that, for example, a functional model will
facilitate estimation of the execution time and memory required. However, obtaining
some skeleton or a prototype of the model of one kind on the basis of another kind
is quite possible.
 The development of various tools for modeling and specification description for
the MBT purposes is required. In spite of the progress in the area of technologies
for development of Domain Specific Languages (DSL), practically, the systems
based on universal languages benefit from the large number of programmers
knowing such languages. The same can be also said about monolingual systems – they
overtake multilingual ones.
 Modern achievements in the area of static and hybrid static-dynamic analysis allow
integration of these techniques into the MBT systems, at that, the
models/specifications as well as software implementations should be the subject of this
analysis.
 To overcome the problems with the extreme lack of specifications in real practice,
tools for work with requirements and models (see, for example, [33]), in particular,
with system models [34, 35] should be developed and deployed. For
multicomponent systems, MBT tools should be integrated with the tools for architecture and
process mining.</p>
          <p>Protoautomata as Models of Systems with Data</p>
          <p>Accumulation
Irina Mikhailova1 and Boris Novikov2 and Grygoriy Zholtkevych2
1 Luhansk Taras Shevchenko National University,
Institute of Information Technology, 2, Oboronna Str., 91011, Luhansk, Ukraine
2 V.N. Karazin Kharkiv National University,
School of Mathematics and Mechanics, 4, Svobody Sqr., 61022, Kharkiv, Ukraine
Abstract. In the paper formal models of software systems and their
components based on the notion of an abstract machine are discussed.
Necessity to model systems with data accumulation sets the problem of
study of generalizations of the notion of an abstract automaton. In the
paper two generalizations, namely, preautomata and protoautomata, are
considered. It is shown that passing from automata via preautomata to
protoautomata can be naturally realized using the language and methods
of category theory.</p>
          <p>
            Keywords. system modelling, abstract automaton, category of automata,
preautomata, category of preautomata, globalization, protoautomaton,
category of protoautomaton, re ector, free protoautomaton
Key terms. MathematicalModel, Speci cationProcess, Veri
cationProcess
1
Theory of abstract state machines or abstract automata is widely applied in
di erent areas of Computer Science. While the early applications of automata
theory were connected with theory of compilators design (see, for example, [
            <xref ref-type="bibr" rid="ref1 ref15">1</xref>
            ]),
the more recent its applications are focused on the problems of speci cation and
veri cation of behaviour of software components [
            <xref ref-type="bibr" rid="ref11 ref17 ref25 ref3">3, 11</xref>
            ]. Such changing of the
object of the theory was marked by R. Milner in [
            <xref ref-type="bibr" rid="ref11 ref25">11</xref>
            ]: \In the classical theory,
rather little attention is paid to the way in which two automata may interact, in
the sense that an action by one entails a complementary action by another. This
kind of interaction requires us to look at automata in new light; in particular, this
interdependency of automata via their actions seems to demand a new approach
to behavioural equivalence".
          </p>
          <p>But the practice of modelling system behaviour based on the automata
approach has shown that the approach is inadequate if data accumulation for the
correct response is necessary.</p>
          <p>
            Using the concept of partial action of a semigroup on a set [
            <xref ref-type="bibr" rid="ref10 ref21 ref24 ref7">7, 10</xref>
            ], we have
de ned the notion of preautomaton and studied its properties [
            <xref ref-type="bibr" rid="ref12 ref18 ref26 ref4">4, 12</xref>
            ]. The further
study has shown that preautomata can be used for modelling some aspects of
behaviour of systems with a delayed response [
            <xref ref-type="bibr" rid="ref13 ref14 ref27 ref28">13, 14</xref>
            ].
          </p>
          <p>
            In this paper, we consider a more general class of automaton-liked systems |
the class of protoautomata. All necessary information from the theory of
semigroups, automata theory, and category theory can be found in the monographs
[
            <xref ref-type="bibr" rid="ref19 ref20 ref22 ref23 ref5 ref6 ref8 ref9">5, 6, 8, 9</xref>
            ].
          </p>
          <p>We use the notation ' : A 99K B for the partial mapping of A to B (unlike
the complete mapping A ! B). If '(a) is not de ned for a 2 A, we write
'(a) = ?. The free monoid on the alphabet is denoted by , and its unit by
". All actions and preactions used in the paper are right, as it is common in the
automata theory.
2</p>
          <p>Preliminaries
We will use the de nition of the automaton in the following form (the condition
of the niteness is ignored):
De nition 1. Given a set X and a free monoid over the alphabet , an
automaton is a mapping X ! X : (x; a) 7! xa such that for all x 2 X
and u; v 2</p>
          <p>x" = x;
x(uv) = (xu)v:
(1)
(2)</p>
          <p>
            More general concept is the following
De nition 2 (see [
            <xref ref-type="bibr" rid="ref18 ref4">4</xref>
            ]). A preautomaton is such a partial mapping of
X 99K X : (x; a) 7! xa, that
a) the condition (1) is ful lled;
b) if xu 6= ? and (xu)v 6= ?, then x(uv) 6= ? and equality (2) is ful lled;
c) if xu 6= ? and x(uv) 6= ?, then (xu)v 6= ? and equality (2) is ful lled.
          </p>
          <p>The preautomata over the monoid
phisms are such maps ' : X ! Y that
form a category PAut( ); its
mor(8 a 2
)(8 x 2 X)( xa 6= ? =) ? 6= '(x)a = '(xa)):
(3)
The category Aut( ) of the automata over is a full subcategory of PAut( ).</p>
          <p>Preautomata appear in the following situation. Let Y be an automaton and
X an arbitrary nonempty subset of Y . Then a restriction of an action on X is a
preautomaton.</p>
          <p>Conversely, let X M 99K X be a preautomaton. The construction which is
inverse to restriction is called globalization. More precisely:
De nition 3. A globalization of the preautomaton X is an automaton Z with
an injection : X ! Z such that for all a 2 , x 2 X
? 6= (x)a = (xa);
xa 6= ? &amp; (xa) = (x)a:
Obviously, is a morphism of PAut(M ). We also call it a globalization.
De nition 4. A globalization : X ! Z is called universal if for any
globalization 0 : X ! Z0 there is an unique morphism { : Z ! Z0 such that 0 = { .
The following construction gives an universal globalization (obviously unique up
to isomorphism) for any preautomaton X 99K X. De ne a relation ` on
the set X :
(x; ab) ` (xa; b) ()
xa 6= ?:
Let ' be an equivalence relation generated by `, and XU = (X )= '. An
equivalence class of ' containing a pair (x; a) is denoted by [x; a]. For [x; a] 2 XU
and b 2 , we set [x; a]b = [x; ab]. Thus a complete action on XU is de ned.
Theorem 1. The automaton XU with a morphism U : X ! XU : x 7! [x; "] is
the universal globalization of the preautomaton X.</p>
          <p>Proof. See [4, Theorem 2]
3</p>
          <p>Protoautomata
(4)
The main object of this paper is a generalization of the notion of preautomaton:
De nition 5. A protoautomaton is a partial mapping X
(x; a) 7! xa such that
99K X :
a) the condition (1) is ful lled;
b) if xu 6= ? and (xu)v 6= ?, then x(uv) 6= ? and equality (2) is ful lled.
We will also denote the protoautomaton from this de nition simply by X, if it
does not cause a confusion.</p>
          <p>Example 1. Let S be a free subsemigroup of and : X S ! X an
automaton. De ne a partial mapping X 99K X as an extension of , putting
xu = ? for u 2 n S; so we get a protoautomaton over . Note that in
general it is not a preautomaton. In addition, this example shows that the
automaton over an in nite alphabet can be represented as a protoautomaton over
a two-letter alphabet.</p>
          <p>Example 2. Let X = fx; yg be a two-element set, L a subset of
protoautomaton X 99K X putting for a 6= "
. De ne a
xa =
y; if a 2 L;
?; if a 2= L;
and ya = ?. This example shows that protoautomata recognize all languages.</p>
          <p>We denote the category of protoautomata with morphisms de ned by the
condition (3) by PtAut( ); clearly, PAut( ) is its subcategory.</p>
          <p>It follows from the theory of partial action of semigroups [6, Theorem 5.7],
that a protoautomaton which is not a preautomaton has no globalization. More
precisely, for the protoautomaton X we can construct an automaton XU as in
Sec. 2, but in this case the morphism U is not injective in general.</p>
          <p>In this situation, the concept of a re ector is useful. We recall its de nition
De nition 6. A subcategory D of a category C is called re ective if with each
object C 2 C an object RD(C) 2 D is associated (called D-re ector of the object
C) and a morphism D(C) : C ! RD(C) (re ection morphism) such that for
each D 2 D the diagram</p>
          <p>C D(!C) RD(C)
can be extended uniquely to a commutative diagram by some morphism out
HomD(RD(C); D).</p>
          <p>It is convenient to use another description of the equivalence ':
Lemma 1. De ne a relation ] on the set X
:
(x; a) ] (y; b) () (9 a0; b0; p 2</p>
          <p>)(a = a0p &amp; b = b0p &amp; xa0 = yb0 6= ?):
Let
be the equivalence relation generated by ]. Then
coincides with '.</p>
          <p>Proof. If (x; a) ] (y; b) then</p>
          <p>(x; a) = (x; a0p) ` (xa0; p) = (yb0; p) a (y; b0p) = (y; b);
whence '.</p>
          <p>Conversely, if (x; a) ` (y; b), then a = cb; y = xc for some c 2
` ]. Consequently, '
. Hence
Remark 1. Obviously, ` is re exive and transitive, while ] is re exive and
symmetric.</p>
          <p>Lemma 2. Let X be a protoautomaton, Y be a preautomaton (both over ),
: X ! Y be a morphism, x; y 2 X, a 2 . Then [x; "] = [y; a] implies
(x) = (y)a 6= ?..</p>
          <p>Proof. It follows from the condition that</p>
          <p>(x; ") ] (z1; b1) ] : : : ] (zn; bn) ] (y; a)
for some z1; : : : ; zn 2 X, b1; : : : ; bn 2</p>
          <p>Proof has completed
Similarly (and even easier) one can prove
Lemma 3. Let X be a protoautomaton, Y be an automaton (both over ),
: X ! Y be a morphism, x; y 2 X, a; b 2 . Then [x; a] = [y; b] implies
(x)a = (y)b.</p>
          <p>Proof is omitted tu</p>
          <p>We set [X; "] = f[x; "] 2 XU j x 2 Xg. Obviously, [X; "], being a subset of
XU , is a preautomaton, and in addition, U (X) = [X; "].
(z1)b1. Suppose
bn = cp; a = dp; znc = yd 6= ?
for some c; d; p 2 . Then (zn)c 6= ? and by the induction
Since Y is a preautomaton then
(zn)(cp) 6= ?.
(x) =
(zn)(cp) =
(znc)p =
(yd)p = ( (y)d)p =
(y)a:
tu
Theorem 2. Let X be a protoautomaton over
, then
1. [X; "] is a re ector for X in the category PAut( ),
2. XU is a re ector for X in Aut( ),
3. XU is a re ector for [X; "] in Aut( ).</p>
          <p>
            Proof. 1) Let Y be some preautomaton and : X ! Y be a morphism of
protoautomata. The required morphism : [X; "] ! Y is uniquely determined
from the equality = U . Indeed, for x 2 X we have (x) = U (x) = ([x; "]).
It follows from Lemma 2 that is well-de ned.
2) Similarly, using Lemma 3.
3) Follows from 1), 2), and the following well-known fact [
            <xref ref-type="bibr" rid="ref23 ref9">9</xref>
            ]:
If A B C are categories, A is re ective in B, and B is re ective in C, then A
is re ective in C. Moreover, the re ection morphism from C to A is the product
of the corresponding re ection morphisms from C to B and from B to A
Corollary 1. Aut( ) is a re ective subcategory of PAut( ). Moreover, the
universal globalization of a preautomaton is its re ector.
          </p>
          <p>Example 3. Let X = fx; y; z; tg, p; u; v 2 n f"g. We set zu = zv = t; z(up) =
x; z(vp) = y and sw = ? for all s 2 X; w 2 n f"; p; u; vg. In such a
manner X turns into a protoautomaton. Since (x; ") ] (z; up) ] (z; vp) ] (y; ")
then [x; "] = [y; "] and the re ection morphism of X is non-injective.</p>
          <p>
            A large class of protoautomata is contained in the following example.
Example 4. Consider a preautomaton X 99K X as a directed weighted
multigraph with states as vertices and with edges of the form (x; u; y), where
x; y 2 X, u 2 , and y = xu. Let U be an arbitrary subset of edges of X. Build
a transitive closure U t of the set U , extending it step by step by the rule: if the
edges (x; u; y) and (y; v; z) are at some stage in the expansion, then on the next
step we include the edge (x; uv; z). Then U t is a protoautomaton.
Example 3 shows that there exists a protoautomaton such that it can not be
embedded into some preautomaton (and thus into some automaton).
4
It is well known [
            <xref ref-type="bibr" rid="ref16 ref2">2</xref>
            ] that free automata play a signi cant role in the theory of
automata (for example, in the problem of constructing a minimal realization).
Therefore, it is advisable to consider the question about the existence of free
objects in the category of protoautomata.
          </p>
          <p>Recall the necessary de nitions:
De nition 7. Let C and D be categories, F : C D be a functor, C be an object
of C. An object D of D is called free on C with respect to the functor F ,
if there is a morphism : C ! F D such that for any object D0 2 D and any
morphism : C ! F D0 there exists the unique morphism : D ! D0 such that
F ( )
= :</p>
          <p>We consider a category Rel( ) whose objects are pairs (X; ), where X is
a set (X 2 Set), X is a binary relation such that X f"g .
A morphism : (X; ) ! (Y; ) of Rel( ) is a map : X ! Y such that
( x; u) 2 for (x; u) 2 .</p>
          <p>Next, let F be a forgetful functor F : PtAut( )
protoautomaton X 99K X to the pair (X; ) with
Rel( ) mapping each
= f(x; u) j xu 6= ?g.</p>
          <p>Theorem 3. For each object (X; ) 2 Rel( ) there is a protoautomaton that is
free on it with respect to the forgetful functor F .</p>
          <p>Proof. For (X; ) 2 Rel( ) construct a protoautomaton M = (
de ning the action by the rule
99K ),
(x; u)v =
(x; uv); if (x; uv) 2</p>
          <p>?; if (x; uv) 2= :
Then F M = ( ; ^), where ^ = f((x; u); v) j (x; u)v = (x; uv)g . De ne
the morphism : (X; ) ! ( ; ^) by the formula (x) = (x; ").</p>
          <p>Let us show that M is a free protoautomaton on (X; ).</p>
          <p>Let N = (Y 99K Y ) be some protoautomaton and F Y = (Y; ). For the
required morphism : M ! N of (5) we have:</p>
          <p>(x; ") = F ( )(x; ") = F ( ) (x) = (x):
Then for any u 2
one can obtain</p>
          <p>(x; u) = (x; ")u = (x)u;
is uniquely determined
Conclusion
tu
It seems that the class of protoautomata, which has been introduced in the
paper, gives the most abstract models for systems with discrete behaviour. This
class of abstract machines includes not only machines reacting on the received
data immediately, as automata, but it also includes machines whose reactions
depend on the accumulated information.</p>
          <p>
            The machines of this class having a greedy behaviour are united into a
subclass whose instances are called preautomata. Machines of the subclass are used
for modelling behaviour systems for complex event processing as it was shown
earlier [
            <xref ref-type="bibr" rid="ref13 ref14 ref27 ref28">13, 14</xref>
            ]. This class of machines, in contrast to the class of automata, is
closed under structural decomposition, and hence, is more suitable for
specifying complex systems. But the condition c) in the de nition of a preautomaton
(see De nition 2) seems unnatural. This condition also impedes de nition of a
nondeterministic preautomaton.
          </p>
          <p>Therefore, by eliminating the condition c) we provide a possibility to study
nondeterministic models. In our opinion, the models derived in this way
(protoautomata) are interesting objects that can be used for speci cation and
verication of complex systems.</p>
        </sec>
        <sec id="sec-3-1-4">
          <title>Models of Class Specification Intersection of Object</title>
        </sec>
        <sec id="sec-3-1-5">
          <title>Oriented Programming</title>
          <p>Dmitriy Buy1 and Serhiy Kompan1
Taras Shevchenko National University of Kyiv, Faculty of Cybernetics,
03680 Academician Glushkov Avenue 4d, Kyiv, Ukraine
Abstract. This paper describes the application of heterogeneous algebraic
system for the construction of the formal model of object database instead of object
algebra. Complete formalization of the operation of intersection of class
specifications is given.</p>
          <p>Keywords. object-oriented programming, object database, object algebra, class
specification</p>
          <p>
            Key terms. MathematicalModel
1
In applications of information technologies there is a problem of construction of the
so-called dependable and stable systems and infrastructures – the systems which
behave stably under all, especially, critical working circumstances. Similarity of risks
and increasing actuality of their decline to an acceptable level for critical applications
led to the appearance of a special term “safeware”, by the analogy with the terms
“hardware”, “software”, “firmware” etc., which combines two components: safe –
secure and ware – a product, an item. This term was suggested and patented by the
leading expert of NASA on the questions of infrastructure security, professor
N. Leveson, who registered the appearance of a modern field of knowledge called
safeware engineering [
            <xref ref-type="bibr" rid="ref1 ref15">1</xref>
            ]. We mention a fundamental statement both obvious, and
elusive in its nature: it’s impossible to talk about stability of a working system,
especially of the infrastructure, if there is no formal model of its operation which has been
constructed and verified. Moreover, for the construction of a formal model, more or
less complex, not “toylike”, there should exist a mathematical apparatus with the help
of which software developers create a formal model and verify it according to the
source demands of a customer could.
          </p>
          <p>
            For the full confidence in the fact that informational system will work stably (will
be dependable and stable), one should single out system components, describe them
formally and verify. Indeed, nowadays there is nothing instead of a “divide and rule”
approach to cope with this difficulty. In fact, one of the most important components
of any complex system (infrastructure) is databases. That’s why there should exist an
appropriate formal model. For the relational databases such a formal model has been
already constructed and explored considerably. This issue is exhaustively covered in
the literature, beginning from the pioneering works by E.F. Codd (see, e.g. [
            <xref ref-type="bibr" rid="ref16 ref2">2</xref>
            ], the
first textbooks [
            <xref ref-type="bibr" rid="ref17 ref18 ref3 ref4">3, 4</xref>
            ] and modern textbooks [
            <xref ref-type="bibr" rid="ref19 ref20 ref5 ref6">5, 6</xref>
            ]). We mention only a collection of
works done by the collaborators of Taras Shevchenko National University of Kiev on
the natural generalization of classical results of the databases relational approaches
[714].
          </p>
          <p>
            Nowadays, there are a lot of formal models of object-oriented databases (OODB)
[
            <xref ref-type="bibr" rid="ref29 ref30 ref31 ref32 ref33 ref34">15-20</xref>
            ]. Each of these models elaborates OODB to a certain extent by applying
certain mathematical apparatus. The analysis of research papers dedicated to OODB has
shown that authors overlook the question arising from the necessity to construct a new
class specification with the two given specifications. For example, the construction of
a super class from two specified classes (the operation of intersection of class
specification), the construction of a subclass from two super classes (the operation of union
of class specification). The intersection of class specifications is important, in our
opinion, as it provides for the opportunity to construct the core of a new program with
two programs which allows integrating these two programs that results in the
Framework version. This paper is dedicated to the exploration of the operation intersection
of class specifications and refining conditions under which the intersection of classes
is possible.
          </p>
          <p>
            Practical results
The authors of this paper have conducted a number of investigations in the field under
research: for example, in the article [
            <xref ref-type="bibr" rid="ref35">21</xref>
            ] it has been suggested to consider an object
algebraic system as a model. Formally it can be formulated like this:
 , ;obj ; spec ,  , where  is a set of objects’ classes,  is a set of class
specification, obj is a set of operations over objects, spec is a set of operations over
class specifications, and a relation      is a partial order which formalizes
inheritance. The main objective of this article is specification of the intersection
operation  and the difference of class specifications.
          </p>
          <p>
            Let’s start with the intersection operation  . Let us formalize the notion of a class:
by a class we mean a pair K  s,   , where s is a functional binary relation which
associates an attribute with its meaning (from a universal domain D ), and  is a
functional binary relation, which brings to conformity a method with its signature.
Therefore [
            <xref ref-type="bibr" rid="ref35">21</xref>
            ], the relations s and  determine a class specification.
          </p>
          <p>The intersection operation (of class specifications) is an operation of the form
 :      , where:  s1, 1    s2 ,  2  s1  s2 , 1   2  , where  is a
standard set-theoretical intersection.</p>
          <p>We will demonstrate some results concerning the structure of a partially ordered
set (poset) F,  , where</p>
          <p>
            is a set of all the functional binary relations (on the
universal domain ), а is an ordinary set-theoretical inclusion. These results will
supplement the results of the paper [
            <xref ref-type="bibr" rid="ref36">22</xref>
            ]. All undetermined notions and designations are
understood in terms of this paper.
          </p>
          <p>Lemma 1. For the arbitrary functional binary relations and the following
equality is true: f  g  ( f  g) (domf  domg) □</p>
          <p>def</p>
          <p>
            Proof. ■ Let us start with X  domf  domg . Let us use generally valid properties
of the set-theoretical restriction operation (a binary ratio on a set) (monotony,
distributivity etc.) [
            <xref ref-type="bibr" rid="ref33">19</xref>
            ].
          </p>
          <p>Firstly, we have an inclusion dom( f  g)  domf  domg  X . Secondly, from this
the next chain of equalities and inequalities follows:
f  g  ( f  g) dom( f  g)  ( f  g) X  f X  g X  f  g .</p>
          <p>Thus, f  g  ( f  g) X  ( f  g ) (domf  domg ) □
def
Below  is a relation of consistency: f  g  f X  g X , where</p>
          <p>
            def
X  domf  domg . In [
            <xref ref-type="bibr" rid="ref21 ref7">7</xref>
            ] the main property of consistency was determined as:
f  g  f  g is a functional binary relation.
          </p>
          <p>The following lemma’s corollary forms another criterion of consistency.</p>
          <p>Corollary (the criterion of consistency of functional binary relations). Let f , g be
arbitrary
functional
binary
relations,
and
f  g  dom( f  g)  X , ( f  g)  dom( f  g)  X . □</p>
          <p>Proof. ■ The proof is performed by using a Lemma 1 and
inclusion dom( f  g)  X . It’s important to note that the second (the first) equivalence is
a formal corollary of the first one (of the second one accordingly). □</p>
          <p>As for the structure of the poset F, , there are two statements.</p>
          <p>Statement 1. Poset</p>
          <p>is a lower semilattice, and at the same time,
inff , g  f  g . □</p>
          <p>
            The proof results from the fact that is a commutative idempotent semigroup and
from a well-known connection between such semigroups and lower semilattices (see,
e.g. [
            <xref ref-type="bibr" rid="ref37">23</xref>
            ]).
          </p>
          <p>More complete information about the poset F, is given by the following
statement.</p>
          <p>Statement 2. (the structure of poset F, ). The following statements are true:
1. The empty function f is the smallest element (“a bottom”)
def
X  domf  domg .</p>
          <p>Then:
2. The largest element in poset F, </p>
          <p>exists if and only if the universe D is
singleton
3. The infimum exists for any nonempty set F and inf F   f F f
4. The supremum of the set F exists if and only if in the case when the set F is
restricted, and supF  f F f
5. The element f is an atom only when f is singleton
6. Poset F,  is a relatively complete poset and a complete (upper) semilattice □
Let’s proceed to the substantial interpretation of above results.</p>
          <p>The operation  constructs a new class which will be basic (paternal) for classes
arguments. This intersection can also be empty, in this case we will get a special
empty class.</p>
          <p>As the relation  on the specifications is component wise
( s,  s,   s  s     ) , all properties of the relation  (statements 1, 2)
can be lifted to the relation  . The corresponding formulations are obvious and
thereby are omitted.
3</p>
          <p>Results and conclusions
The model of intersection operation of class specifications has been examined. This
operation has been specified as set-theoretical intersection. The specification f  g
has been interpreted as the largest total part of f and g , that is, the specification
from which specifications-arguments can be obtained by inheritance (in other words,
the result specification is the specification of a paternal class). The conditions for
nonempty (equivalent, empty) intersection have been examined.</p>
          <p>As for formal results, natural criteria of function consistency have been presented
(corollary) which supplement the already known criteria; the structure of a partially
ordered set of partial functions has been specified (statements 1, 2).</p>
          <p>References
Alferov, Eugene................................... 108
Alobaidi, Mizal...................................... 18
Arkatov, Denis B. ................................ 178
Aronov, Andrey ................................... 252
Baiev, Oleksandr ................................. 118
Baklanova, Nadezhda .......................... 550
Batyiv, Andriy ....................................... 18
Becker, Karsten ................................... 424
Beletsky, Alexsander ........................... 352
Beletsky, Anatoly ........................ 311, 352
Beletsky, Evgeny ................................. 311
Bilousova, Lyudmyla........................... 209
Blinov, Igor Ol..................................... 565
Bodnenko, Dmitry ............................... 281
Bonda, Darya....................................... 360
Buy, Dmitriy........................................ 590</p>
          <p>A
B
C
D
Chaabani, Mohamed ............................ 521
Cochez, Michael .................................. 221
Davidovsky, Maxim ...................... 99, 295
Derevianko, Andrii ................................ 30
Didenko, Ievgen................................... 118
Doroshenko, Anatoliy............................ 38
Dzyubenko, Artem............................... 252
Echahed, Rachid ..................................521
Ermolayev, Vadim ...... II, 64, 99, 108, 295</p>
          <p>E
Kandyba, Roman .................................352
Keberle, Natalya G.................................79
Kharchenko, Vyacheslav .....................146
Klionov, Dmitriy M. ............................464
Kobets, Vitaliy ........................ II, 310, 329
Kolgatin, Oleksandr .............................209
Kolgatina, Larisa..................................209
Kompan, Serhiy ...................................590
Kotkova, Vera......................................236
Kravtsov, Hennadiy ................ II, 236, 410
Kropotov, Aleksandr..............................30
Kryukov, Sergey ..................................310
Kryvolap, Andrii..................................533
Kukharenko, Vladimir .................273, 410
Maksimov, Andrey .............................. 573
Mallet, Frédéric ................... 130, 289, 475
Mantula, Elena....................................... 91
Manzhulam Anna ................................ 195
Mashtalir, Vladimir ............................... 91
Matthes, Ralph..................................... 506
Matzke, Wolf-Ekkehard .......................... 2
Mayr, Heinrich C.................................... II
Mazol, Sergey...................................... 360
Mazol, Sergey...................................... 366
Mesropyan, Karine .............................. 385
Mikhailova, Irina ................................. 582
Moiseeva, Oksana................................ 366
Möller, Dietmar P.F............................. 424
Morze, Natalia ..................................... 264
Morze, Natalia V. ................................ 411</p>
          <p>N
O</p>
          <p>P
Nikitchenko, Mykola .............. II, 447, 533
Novikov, Boris .................................... 582
Odarushchenko, Oleg .......................... 146
Odarushchenko, Valentina................... 146
R
S
T
V
W</p>
          <p>Y
Popov, Peter.........................................146
Pratt, Gary L. ...........................................3
Protsenko, Galina.................................264
Ralo, Aleksandr .....................................30
Richter, Harald.....................................424
Romenska, Yuliia.................................130
Rudenko, Margarita .............................401
Tatarintseva, Olga..................................64
Tirronen, Ville .....................................221
Tkachuk, Nikolay...................................48
Tolok, Vyacheslav .................................99
Payentko, Tanya .................................. 310
Peschanenko, Vladimir ........... II, 447, 490
Petrenko, Alexander K......................... 573
Petukhova, Lyubov.............................. 236
Yatsenko, Olena.....................................38
Valko, Nataliya ....................................195
Varava, Anastasiia ...............................163
Vasylevych, Leonid .............................187
Vozniy, Oleksiy .....................................30
Weissblut, Alexander J. .......................374</p>
          <p>Winckel, Mathias .................................506
Zaporozhchenko, Yulia........................ 410
Zaretska, Iryna..................................... 475
Zavileysky, Mikhail................................ II
Zhereb, Kostiantyn.................................38
Zholtkevych, Galyna............................475
Zholtkevych, Grygoriy..... II, 18, 163, 475,
582</p>
        </sec>
      </sec>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Aho</surname>
            ,
            <given-names>A.V.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ullman</surname>
            ,
            <given-names>J.D.</given-names>
          </string-name>
          : Theory of Parsing, Translation, and Compiling. PrenticeHall, New York (
          <year>1972</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Arbib</surname>
            ,
            <given-names>M.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Manes</surname>
            ,
            <given-names>E.G.</given-names>
          </string-name>
          :
          <article-title>Machines in a category: an expository introduction</article-title>
          .
          <source>SIAM Rev</source>
          .
          <volume>16</volume>
          ,
          <issue>163</issue>
          {
          <fpage>192</fpage>
          (
          <year>1974</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3. Borger, E., Stark, R.:
          <article-title>Abstract State Machines: A Method for High-Level System Design and Analysis</article-title>
          . Springer-Verlag, Berlin Heidelberg (
          <year>2003</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Dokuchaev</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Novikov</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zholtkevych</surname>
          </string-name>
          , G.:
          <article-title>Partial actions and automata</article-title>
          .
          <source>Alg. and Discr</source>
          . Math. Vol.
          <volume>11</volume>
          ,
          <issue>2</issue>
          , 51{
          <fpage>63</fpage>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Eilenberg</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          : Automata,
          <string-name>
            <surname>Languages,</surname>
          </string-name>
          <source>and Machines</source>
          , vol. B. Academic Press, New York (
          <year>1976</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Holcombe</surname>
            ,
            <given-names>W.M.L.</given-names>
          </string-name>
          :
          <article-title>Algebraic Automata Theory</article-title>
          . Cambridge Univ. Press (
          <year>1982</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Hollings</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          :
          <article-title>Partial actions of monoids</article-title>
          .
          <source>Semigroup Forum</source>
          .
          <volume>75</volume>
          ,
          <issue>293</issue>
          {
          <fpage>316</fpage>
          (
          <year>2007</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Lallement</surname>
          </string-name>
          , G.:
          <article-title>Semigroups and combinatorial applications</article-title>
          . John Wiley, New York (
          <year>1979</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>MacLane</surname>
          </string-name>
          , S.:
          <article-title>Categories for the Working Mathematician</article-title>
          . Springer, Berlin (
          <year>1971</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Megrelishvili</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          , Schroder, L.:
          <article-title>Globalization of con uent partial actions on topological and metric spaces</article-title>
          .
          <source>Topol. and Appl</source>
          .
          <volume>145</volume>
          ,
          <issue>119</issue>
          {
          <fpage>145</fpage>
          (
          <year>2004</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Milner</surname>
          </string-name>
          , R.:
          <source>Communicating and Mobile Systems: The Pi Calculus</source>
          . Cambridge University Press, Cambridge (
          <year>1999</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Novikov</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Perepelytsya</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zholtkevych</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          <article-title>Pre-automata as mathematical models of event ows recognisers</article-title>
          . In: V.
          <string-name>
            <surname>Ermolayev</surname>
          </string-name>
          et al.
          <source>(eds.) Proc. 7-th Int. Conf. ICTERI</source>
          <year>2011</year>
          ,
          <volume>41</volume>
          {
          <fpage>50</fpage>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Perepelytsya</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zholtkevych</surname>
          </string-name>
          , G.:
          <article-title>On some class of mathematical models for static analysis of critical-mission asynchronous systems</article-title>
          .
          <source>Syst. ozbr. ta viysk. tehn</source>
          . Vol.
          <volume>27</volume>
          ,
          <issue>3</issue>
          , 60{
          <fpage>63</fpage>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Perepelytsya</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zholtkevych</surname>
          </string-name>
          , G.:
          <article-title>Hierarchic Decomposition of Pre-machines as Models of Software System Components</article-title>
          .
          <source>Syst. upravl. navig. i zv'iazku</source>
          . Vol.
          <volume>20</volume>
          ,
          <issue>4</issue>
          , 233{
          <fpage>238</fpage>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          1.
          <string-name>
            <surname>Kharchenko</surname>
            ,
            <given-names>V. S.:</given-names>
          </string-name>
          <article-title>Safety of Critical Infrastructures: Mathematical and Engineering Methods of Analysis and Ensuring</article-title>
          . N.E. Zhukovsky National Aerospace University (
          <year>2011</year>
          )
          <article-title>(in Russian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          2.
          <string-name>
            <surname>Codd</surname>
            ,
            <given-names>E. F.</given-names>
          </string-name>
          :
          <article-title>A Relational Model of Data for Large Shared Data Banks</article-title>
          .
          <source>Comm. ACM</source>
          ,
          <volume>13</volume>
          (
          <year>1970</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          3.
          <string-name>
            <surname>Maier</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>The Theory of Relational Databases</article-title>
          . Computer Science Press (
          <year>1983</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          4.
          <string-name>
            <surname>Ullman</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Garsia-Molina</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Widom</surname>
          </string-name>
          , J.:
          <article-title>Database Systems: The Complete Book</article-title>
          . Prentice Hall Inc.,
          <string-name>
            <surname>Stanford</surname>
          </string-name>
          (
          <year>2002</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref19">
        <mixed-citation>
          5.
          <string-name>
            <surname>Kroenke</surname>
            ,
            <given-names>D. M.</given-names>
          </string-name>
          : Database Processing: Fundamentals, Design, and
          <string-name>
            <surname>Implementation</surname>
          </string-name>
          . Prentice
          <string-name>
            <surname>Hall</surname>
          </string-name>
          (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref20">
        <mixed-citation>
          6.
          <string-name>
            <surname>Date</surname>
            ,
            <given-names>C. J.:</given-names>
          </string-name>
          <article-title>An Introduction to Database Systems</article-title>
          . In: Addison-Wesley,
          <article-title>(</article-title>
          <year>2000</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref21">
        <mixed-citation>
          7.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kahuta</surname>
            ,
            <given-names>N. D.</given-names>
          </string-name>
          : Full Image, Restriction, Projection,
          <string-name>
            <given-names>Relationship</given-names>
            <surname>Compatibility</surname>
          </string-name>
          .
          <source>Theoretical and Applied Aspects of Program Systems Development: International Conference, December</source>
          <volume>8</volume>
          -
          <issue>10</issue>
          , pp.
          <fpage>244</fpage>
          -
          <lpage>260</lpage>
          (
          <year>2009</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref22">
        <mixed-citation>
          8.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Bogatiryova</surname>
            ,
            <given-names>J. A.</given-names>
          </string-name>
          :
          <article-title>The Theory of Multisets: Bibliography, Use the Table in Databases</article-title>
          .
          <source>Radio Electronic and Computer Systems</source>
          ,
          <volume>7</volume>
          (
          <issue>48</issue>
          ),
          <fpage>56</fpage>
          -
          <lpage>62</lpage>
          (
          <year>2010</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref23">
        <mixed-citation>
          9.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Polyakov</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          :
          <article-title>Compositional Semantics of Recursive Queries in SQL-like Languages</article-title>
          . Bulletin of Kyiv University. Series. Phis.-Math. Science,
          <volume>1</volume>
          ,
          <fpage>45</fpage>
          -
          <lpage>56</lpage>
          (
          <year>2010</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref24">
        <mixed-citation>
          10.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Glushko</surname>
            ,
            <given-names>I. M.</given-names>
          </string-name>
          :
          <article-title>Generalized Table Algebra, Generalized Tuple Calculus, Generalized Domain Calculus and Theirs Equivalence</article-title>
          . In: Bulletin of Kyiv University. Series. Phys.-Math. Science.
          <volume>1</volume>
          ,
          <fpage>86</fpage>
          -
          <lpage>95</lpage>
          (
          <year>2011</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref25">
        <mixed-citation>
          11.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Puzikova</surname>
          </string-name>
          , А. V.:
          <article-title>Completeness of Armstrong Axioms</article-title>
          . In: Bulletin of Kyiv University. Series. Phys.-Math. Science,
          <volume>3</volume>
          ,
          <fpage>103</fpage>
          -
          <lpage>108</lpage>
          , (
          <year>2011</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref26">
        <mixed-citation>
          12.
          <string-name>
            <surname>Redko</surname>
            ,
            <given-names>V. N.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brona</surname>
            ,
            <given-names>J. Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Polyakov</surname>
            ,
            <given-names>S. A.</given-names>
          </string-name>
          :
          <article-title>Relational Databases: Tabular Algebra and SQL-like Language</article-title>
          .
          <source>AcademPeriodika</source>
          (
          <year>2001</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref27">
        <mixed-citation>
          13.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Silveystruk</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          :
          <article-title>Formalization of Structural Constraints of Relationships in «Entity-Relationship» Model</article-title>
          .
          <source>In: Electronic Computers and Informatics</source>
          <year>2006</year>
          : International Scientific Conference,
          <source>September 20-22</source>
          , pp.
          <fpage>96</fpage>
          -
          <lpage>101</lpage>
          , Kosice, Slovakia (
          <year>2006</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref28">
        <mixed-citation>
          14.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Glushko</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          :
          <article-title>Equivalence of Table Algebras of Finite (Infinite) Tables and Corresponding Relational Calculi</article-title>
          .
          <source>In: Proceedings of the Eleventh International Conference on Informatics INFORMATICS'2011, November 16-18</source>
          , pp.
          <fpage>56</fpage>
          -
          <lpage>60</lpage>
          . Rožňava, Slovakia, (
          <year>2011</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref29">
        <mixed-citation>
          15.
          <string-name>
            <surname>Piskunov</surname>
          </string-name>
          , А. G.:
          <article-title>The Formalization of the Object-Oriented Programming Paradigm</article-title>
          , http://www.realcoding.net/dn/docs/machine.pdf (in Russian)
        </mixed-citation>
      </ref>
      <ref id="ref30">
        <mixed-citation>
          16.
          <string-name>
            <surname>Piskunov</surname>
            ,
            <given-names>A. G.</given-names>
          </string-name>
          :
          <article-title>The Formalization of the OOP: Types</article-title>
          , Sets, Classes, http://agp1.hx0.ru/articles/typeSetsClasses.pdf (in Russian)
        </mixed-citation>
      </ref>
      <ref id="ref31">
        <mixed-citation>
          17.
          <string-name>
            <surname>Chaplanova</surname>
          </string-name>
          , Е. B.:
          <article-title>Operating Specification of Object-Relational Data Model</article-title>
          . Radіoelektronіka, Informatika, Upravlіnnya,
          <volume>12</volume>
          ,
          <fpage>75</fpage>
          -
          <lpage>79</lpage>
          (
          <year>2011</year>
          )
          <article-title>(in Russian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref32">
        <mixed-citation>
          18.
          <string-name>
            <surname>Richta</surname>
            ,
            <given-names>K</given-names>
          </string-name>
          , Toth,
          <string-name>
            <surname>D.</surname>
          </string-name>
          :
          <article-title>Formal Models of Object-Oriented Databases</article-title>
          .
          <source>In: Objekty</source>
          <year>2008</year>
          . Žilina: Žilinská univerzita v Žiline,
          <source>Fakulta Riadenia a Informatiky</source>
          , pp.
          <fpage>204</fpage>
          -
          <lpage>217</lpage>
          , http://www.ksi.mff.cuni.cz/~richta/publications/richta-toth-Objekty2008.pdf (
          <year>2008</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref33">
        <mixed-citation>
          19.
          <string-name>
            <surname>Sarkar</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Reiss</surname>
            ,
            <given-names>S.:</given-names>
          </string-name>
          <article-title>A Data Model and a Query Language for Object-Oriented Database</article-title>
          . In: Island, Department of Computer Science Brown University Providence, Rhode, CS-
          <volume>92</volume>
          - 57, http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.34.4531&amp;
          <article-title>rep=rep1&amp;type= pdf (</article-title>
          <year>1992</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref34">
        <mixed-citation>
          20.
          <string-name>
            <surname>Gail</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shaw</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>Zdonik A Query Algebra for Object-Oriented Databases</article-title>
          . Island, Department of Computer Science Brown University Providence, Rhode, CS-
          <volume>89</volume>
          -19 http://trac.common-lisp.net/elephant/raw-attachment/wiki/RelationalAlgebra/shaw89 query.2.
          <string-name>
            <surname>pdf</surname>
          </string-name>
          (
          <year>1989</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref35">
        <mixed-citation>
          21.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kompan</surname>
            ,
            <given-names>S. V.</given-names>
          </string-name>
          :
          <article-title>Union and Intersection Operations of Classes Specifications in Heterogen Algebraic System for Object-Oriented Programming</article-title>
          .
          <source>In: Proc. SWorld. Int. SciPract. Conf. Modern Problems</source>
          and Solutions in Science, Transportation, Manufacturing and
          <string-name>
            <surname>Education. KUPRIENKO</surname>
          </string-name>
          , Odessa, vol.
          <volume>4</volume>
          , pp.
          <fpage>45</fpage>
          -
          <lpage>49</lpage>
          (
          <year>2012</year>
          )
          <article-title>(in Russian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref36">
        <mixed-citation>
          22.
          <string-name>
            <surname>Buy</surname>
            ,
            <given-names>D. B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kahuta</surname>
            ,
            <given-names>N. D.</given-names>
          </string-name>
          :
          <article-title>Properties Related Confinality and Order a Set of Partial Functions</article-title>
          . Bulletin of Kyiv University. Series. Phys.-Math. Science,
          <volume>2</volume>
          ,
          <fpage>125</fpage>
          -
          <lpage>135</lpage>
          , (
          <year>2006</year>
          )
          <article-title>(in Ukrainian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref37">
        <mixed-citation>
          23.
          <string-name>
            <surname>Skornyakov</surname>
            ,
            <given-names>L. A.</given-names>
          </string-name>
          :
          <article-title>Elements of the Theory of Structures</article-title>
          . Nauka,
          <string-name>
            <surname>Мoskow</surname>
          </string-name>
          (
          <year>1982</year>
          )
          <article-title>(in Russian)</article-title>
        </mixed-citation>
      </ref>
      <ref id="ref38">
        <mixed-citation>
          <string-name>
            <surname>Schreiner</surname>
            ,
            <given-names>Wolfgang ............................533</given-names>
          </string-name>
          <string-name>
            <surname>Selyutin</surname>
            ,
            <given-names>Victor....................................401</given-names>
          </string-name>
          <string-name>
            <surname>Semenyuk</surname>
            ,
            <given-names>Andriy ...............................393</given-names>
          </string-name>
          <string-name>
            <surname>Shushpanov</surname>
            ,
            <given-names>Constantin.......................490</given-names>
          </string-name>
          <string-name>
            <surname>Shyshkina</surname>
            ,
            <given-names>Mariya ...............................</given-names>
          </string-name>
          436 Sitzmann,
          <string-name>
            <given-names>Daniel..................................424</given-names>
            <surname>Sokol</surname>
          </string-name>
          ,
          <string-name>
            <given-names>Vladyslav....................................48</given-names>
            <surname>Spivakovska</surname>
          </string-name>
          ,
          <string-name>
            <given-names>Evgeniya ........................236</given-names>
            <surname>Spivakovskiy</surname>
          </string-name>
          ,
          <string-name>
            <surname>Aleksander............... II</surname>
          </string-name>
          , 236 Strecker,
          <string-name>
            <surname>Martin ...................</surname>
          </string-name>
          <volume>447</volume>
          ,
          <issue>521</issue>
          , 550 Styervoyedov,
          <string-name>
            <surname>Sergiy.............................30</surname>
          </string-name>
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>