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    <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>Lviv</institution>
          ,
          <addr-line>Ukraine May, 2015 Sotiris Batsakis</addr-line>
        </aff>
      </contrib-group>
      <fpage>539</fpage>
      <lpage>580</lpage>
      <kwd-group>
        <kwd>and Industrial Applications</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>ICTERI 2015
Batsakis, S., Mayr, H. C., Yakovyna, V., Nikitchenko, M., Zholtkevych, G.,
Kharchenko, V., Kravtsov, H., Kobets, V., Peschanenko, V., Ermolayev, V., Bobalo,
Yu. and Spivakovsky, A., (Eds.): ICT in Education, Research and Industrial
Applications: Integration, Harmonization and Knowledge Transfer. Proc. 11th Int.</p>
    </sec>
    <sec id="sec-2">
      <title>Conf. ICTERI 2015, Lviv, Ukraine, May 14-16, 2015, CEUR-WS.org, online</title>
      <p>This volume represents the proceedings of the 11th International Conference on
ICT in Education, Research, and Industrial Applications, held in Lviv, Ukraine, in
May 2015. It comprises 45 contributed papers that were carefully peer reviewed (3-4
reviews per paper) and selected from 119 submissions.</p>
      <p>The volume opens with the abstracts of the keynote talks and tutorial. The rest of
the collection is organized in 2 parts. Part I contains the contributions to the main
ICTERI conference, structured in four topical sections: (1) Teaching ICT and Using
ICT in Education; (2) Model-Based Software System Development; (3) Machine
Intelligence, Knowledge Engineering and Management for ICT; and (4) ICT in
Industrial Applications. Part II comprises the contributions of the four workshops
colocated with ICTERI 2015, namely: the International Workshop on Information
Technologies in Economic Research (ITER 2015); the International Workshop on
Methods and Resources of Distance Learning (MRDL 2015); the International
Workshop on Algebraic, Logical, and Algorithmic Methods of System Modeling,
Specification and Verification (SMSV 2015); and the International Workshop on Theory of</p>
    </sec>
    <sec id="sec-3">
      <title>Reliability for Modern Information Technologies (TheRMIT 2015).</title>
      <sec id="sec-3-1">
        <title>Copyright © 2015 for the individual papers by the papers’ authors.</title>
      </sec>
      <sec id="sec-3-2">
        <title>Copying permitted only for private and academic purposes. This volume is published and copyrighted by its editors.</title>
        <p>ICTERI, the International Conference on Information and Communication
Technologies in Education, Research, and Industrial Applications: Integration,
Harmonization, and Knowledge Transfer, has become a considerable and stable international
ICT conference. It is a real pleasure for all ICTERI players, that in contrast to 2014,
the 11th edition could bring scholars and expert representatives physically together
again for exchanging and discussing new ideas and findings, and for networking
across all political borders. This is all the more pleasing as, despite of all current
challenges, the Ukrainian ICT community proves its vigor and global integration.</p>
        <p>We gladly present you the proceedings of ICTERI 2015, which was held in Lviv,
Ukraine, on May 14-16, 2015. The conference scope was determined by the
cornerstones of ICT Infrastructures and Techniques, Knowledge Based Systems,
Academia/Industry ICT Cooperation, and ICT in education. Special emphasis was given to
real world applications of ICT solutions. Therefore, the contributions had to describe
original, not previously published work, and to demonstrate how and to what purpose
and extent the proposed solutions are applied or transferred into use.</p>
        <p>For the main conference, 42 full papers were submitted and evaluated by at least
three peers per paper. Finally, 16 have been selected and accepted after revision in
accordance with the reviewers comments. This corresponds to an acceptance rate of
38%. The program was rounded off with the two outstanding keynote talks on
Rigorous Semantics and Refinement for Business Processes by Klaus-Dieter Schewe and on
Smart Learning Environments: a Shift of Paradigm by David Esteban. The tutorial on
Systematic Business Process Modeling in a Nutshell by Heinrich C. Mayr
complemented the program, in particular regarding the emphasis on the synergy of education
and industrial applications.</p>
        <p>ICTERI 2015 continued the tradition of hosting co-located events, this year by
offering four workshops:
 4th Int. Workshop on Information technologies in economic research (ITER 2015)
 3rd Int. Workshop on Methods and Resources for Distance Learning (MRDL 2015)
 4th Int. Workshop on Algebraic, Logical, and Algorithmic Methods of System</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>Modeling, Specification and Verification (SMSV 2015)</title>
      <p> Int. Workshop on Theory of Reliability for Modern Information Technologies
(TheRMIT 2015)</p>
      <p>In total, these workshops attracted 77 submissions, from which 29 were selected by
the particular program committees. This again led to an acceptance rate of 38%.</p>
      <p>Clearly, the conference would not have been possible without the engaged support
of many people including the authors, members of our Program Committee, workshop
organizers and their program committees, local organizers, and, last but not least,
generous donators. We express our special thanks to all of them.</p>
      <p>May, 2015</p>
      <p>Sotiris Batsakis, Heinrich C. Mayr, Vitaliy Yakovyna, Mykola Nikitchenko,
Grygoriy Zholtkevych, Vyacheslav Kharchenko, Hennadiy Kravtsov, Vitaliy Kobets,
Vladimir Peschanenko, Vadim Ermolayev, Yuriy Bobalo, Aleksander Spivakovsky</p>
      <sec id="sec-4-1">
        <title>Committees</title>
        <p>General Chairs
Steering Committee</p>
        <p>Yuriy Bobalo, Lviv Polytechnic National University, Ukraine
Aleksander Spivakovsky, Kherson State University, Ukraine
Vadim Ermolayev, Zaporizhzhya National University, Ukraine
Aleksander Spivakovsky, Kherson State University, Ukraine</p>
        <p>Mikhail Zavileysky, DataArt, Russian Federation
Local Organization Chair</p>
        <p>Dmytro Fedasyuk, Lviv Polytechnic National University, Ukraine
Program Chairs
Workshop Chairs
Tutorial Chair
IT Talks Chairs</p>
        <p>Vadim Ermolayev, Zaporizhzhya National University, Ukraine
Heinrich C. Mayr, Alpen-Adria-Universät Klagenfurt, Austria
Mykola Nikitchenko, Taras Shevchenko National University of Kyiv, Ukraine
Aleksander Spivakovsky, Kherson State University, Ukraine
Mikhail Zavileysky, DataArt, Russian Federation
Grygoriy Zholtkevych, V.N.Karazin Kharkiv National University, Ukraine
Sotiris Batsakis, University of Huddersfield, UK
Heinrich C. Mayr, Alpen-Adria-Universität Klagenfurt, Klagenfurt, Austria
Vitaliy Yakovyna, Lviv Polytechnic National University, Ukraine
Mykola Nikitchenko, Taras Shevchenko National University of Kyiv, Ukraine
Grygoriy Zholtkevych, V.N.Karazin Kharkiv National University, Ukraine
Publicity Chair
Web Chair</p>
        <p>Nataliya Kushnir, Kherson State University, Ukraine</p>
        <p>Eugene Alferov, Kherson State University, Ukraine
Program Committees</p>
        <p>MAIN ICTERI 2015 Conference</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Program Committee</title>
      <p>Carlos Ruiz, playence, Spain
Abdel-Badeeh Salem, Ain Shams University, Cairo, Egypt
Wolfgang Schreiner, RISC, Johannes Kepler University Linz, Austria
Pavlo Serdyuk, Lviv Polytechnic National University, Ukraine
Vladimir A. Shekhovtsov, Alpen-Adria-Universität Klagenfurt, Austria
Mariya Shishkina, Institute of Information Technologies and Learning Tools
of the National Academy of Pedagogical Sciences of Ukraine, Ukraine
Martin Strecker, IRIT, Paul Sabatier University, Toulouse, France
Ilias Tachmazidis, University of Huddersfield, UK
Olga Tatarintseva, Satelliz, Ukraine
Vagan Terziyan, University of Jyväskylä, Finland
Ville Tirronen, University of Jyvaskyla, Finland
Nikolay Tkachuk, National Technical University "Kharkiv Polytechnic Institute”, Ukraine
Mauro Vallati, University of Huddersfield, UK
Leo Van Moergestel, Utrecht University of Applied Sciences, The Netherlands
Maxim Vinnik, Kherson State University, Ukraine
Paul Warren, Knowledge Media Institute, the Open University, UK
Vitaliy Yakovyna, Lviv Polytechnic National University, Ukraine
Yulia Nosenko (Zaporozhchenko), Institute of Information Technologies and Learning Tools
of the National Academy of Pedagogical Sciences of Ukraine, Ukraine
Iryna Zaretska, V. N. Karazin Kharkiv National University, Ukraine</p>
    </sec>
    <sec id="sec-6">
      <title>Grygoriy Zholtkevych, V. N. Karazin Kharkov National University, Ukraine</title>
    </sec>
    <sec id="sec-7">
      <title>Additional Reviewers</title>
      <p>Kalliopi Kravari, Aristotle University of Thessaloniki, Greece
Rustam Gamzaev, National Technical University "Kharkiv Polytechnic Institute”, Ukraine
Eleftherios Spyromitros-Xioufis, Aristotle University of Thessaloniki, Greece
Emmanouil Rigas, Aristotle University of Thessaloniki, Greece
ITER 2015 Workshop</p>
    </sec>
    <sec id="sec-8">
      <title>Workshop Chairs</title>
      <p>Vitaliy Kobets, Kherson State University, Ukraine
Sergey Kryukov, Southern Federal University, Russian Federation
Sergey Mazol, Academy of Public Administration, Minsk, Belarus
Tatyana Payentko, National University of State Tax Service of Ukraine, Ukraine</p>
    </sec>
    <sec id="sec-9">
      <title>Program Committee</title>
      <p>Tom Coupe, Kyiv School of Economics, Ukraine
Dorota Jelonek, Częstochowa University of Technology, Poland
Ludmila Konstants, American University of Central Asia, Kyrgyz Republic
Sergey Kryukov, Southern Federal University, Russian Federation
Sergey Mazol, Academy of Public Administration, Minsk, Belarus
Marin Neykov, University of National and World Economy (UNWE), Bulgaria
Nina Solovyova, Kherson State University, Ukraine
Ekaterina Vostrikova, Astrakhan State University, Russian Federation
Alexander Weissbult, Kherson State University, Ukraine
MRDL 2015 Workshop</p>
    </sec>
    <sec id="sec-10">
      <title>Workshop Chairs</title>
      <p>Vladimir Kukharenko, National Technical University “Kharkiv Polytechnic Institute”, Ukraine
Yulia Nosenko (Zaporozhchenko), Institute of Information Technologies and Learning Tools
of the National Academy of Pedagogical Sciences of Ukraine, Ukraine
Hennadiy Kravtsov, Kherson State University, Ukraine
Olga Gnedkova, Kherson State University, Ukraine
Alexander Kolgatin, H.S. Skovoroda Kharkiv National Pedagogical University, Ukraine
Evgen Kozlovskiy, Kherson State University, Ukraine
Vladislav Kruglik, Kherson State University, Ukraine
Michael Sherman, Kherson State University, Ukraine
Maria Shishkina, Institute of Information Technologies and Learning Tools</p>
      <p>of the National Academy of Pedagogical Sciences of Ukraine, Ukraine
Tatyana Zaytseva, Kherson State Maritime Academy, Ukraine
SMSV 2015 Workshop</p>
    </sec>
    <sec id="sec-11">
      <title>Workshop Chairs</title>
      <p>Wolfgang Schreiner, RISC, Johannes Kepler University Linz, Austria
Mykola Nikitchenko, Taras Shevchenko National University of Kyiv, Ukraine
Michael Lvov, Kherson State University, Ukraine
Martin Strecker, IRIT, Paul Sabatier University, France</p>
    </sec>
    <sec id="sec-12">
      <title>Program Committee</title>
      <p>Anatoliy Doroshenko, Glushkov Institute of Cybernetics of the National Academy of Sciences
of Ukraine, Ukraine
Louis Feraud, Paul Sabatier University, France
Alexander Letichevsky, Glushkov Institute of Cybernetics of the National Academy of Sciences
of Ukraine, Ukraine
Alexander Lyaletski, Taras Shevchenko National University of Kyiv, Ukraine
Frederic Mallet, University of Nice Sophia Antipolis, France
Vladimir Peschanenko, Kherson State University, Ukraine
TheRMIT 2015 Workshop</p>
    </sec>
    <sec id="sec-13">
      <title>Workshop Chairs</title>
      <p>Vyacheslav Kharchenko, National Aerospace University “KhAI”, Ukraine
Elena Zaitseva, Žilina University, Slovakia
Bogdan Volochiy, Lviv Polytechnic National University, Ukraine</p>
    </sec>
    <sec id="sec-14">
      <title>Program Committee</title>
      <p>Mario Fusani, ISTI-CNR System and Software Evaluation Center, Italy
Vladimir Sklyar, National Aerospace University "KhAI", Ukraine
Iosif Androulidakis, Ioannina University Network Operations Center, Greece
Yuriy Kondratenko, Black Sea State University named after Petro Mohyla, Ukraine
Vitaly Levashenko, Žilina University, Slovakia
Dmitriy Maevskiy, Odessa National Polytechnic University, Ukraine
Vladimir Mokhor, Pukhov Institute for Modeling in Energy Engineering, NASU, Ukraine
Oleg Odarushchenko, Research and Production Company Radiy, Ukraine
Olexandr Gordieiev, University of Banking of National Bank of Ukraine, Kyiv, Ukraine
Yurij Ponochovny, Poltava National Technical University, Ukraine
Jüri Vain, Tallinn University of Technology, Estonia
Sergiy Vilkomir, East Carolina University, USA</p>
      <p>Vladimir Zaslavskiy, Taras Shevchenko National University of Kyiv, Ukraine
Local Organizing Committee</p>
    </sec>
    <sec id="sec-15">
      <title>Oleksandr Spivakovsky’s Educational Foundation (OSEF,</title>
      <p>http://spivakovsky.fund/) aims to support gifted young people,
outstanding educators, and also those who wish to start up
their own business. OSEF activity is focused on the support
and further development of educational, scientific, cultural,
social and intellectual spheres in the Kherson Region of</p>
    </sec>
    <sec id="sec-16">
      <title>Ukraine.</title>
    </sec>
    <sec id="sec-17">
      <title>DataArt (http://dataart.com/) develops industry-defining ap</title>
      <p>plications, helping clients optimize time-to-market and
minimize software development risks in mission-critical systems.</p>
    </sec>
    <sec id="sec-18">
      <title>Domain knowledge, offshore cost advantages, and efficiency – that's what makes DataArt a partner of choice for their global clients.</title>
      <p>Lviv Polytechnic National University
(http://www.lp.edu.ua/en) is the largest technological
university in Lviv. Since its foundation in 1844, it was one of the most
important centres of science and technological development in</p>
    </sec>
    <sec id="sec-19">
      <title>Central Europe. Presently, the university comprises 16 institutes where students from Ukraine and other countries are enrolled in 64 bachelor, 123 master, and 99 PhD programmes.</title>
      <p>Logicify (http://logicify.com/) is an outsourcing company
providing software development services. Compay helps
customers with issues and projects involving software. Logicify
has been working in a variety of industries and fields,
including telecom, video sharing, social media, insurance. It has
several teams with specialized skills in different technologies
that can relate to specific industries.</p>
      <sec id="sec-19-1">
        <title>Organizers</title>
        <sec id="sec-19-1-1">
          <title>Ministry of Education and Science of Ukraine http://www.mon.gov.ua/</title>
        </sec>
        <sec id="sec-19-1-2">
          <title>Lviv Polytechnic National University, Ukraine http://www.lp.edu.ua/en</title>
        </sec>
        <sec id="sec-19-1-3">
          <title>University of Huddersfield, UK http://www.hud.ac.uk/</title>
        </sec>
        <sec id="sec-19-1-4">
          <title>Alpen-Adria-Universität Klagenfurt, Austria http://www.uni-klu.ac.at/</title>
        </sec>
        <sec id="sec-19-1-5">
          <title>Kherson State University, Ukraine http://www.kspu.edu/</title>
        </sec>
        <sec id="sec-19-1-6">
          <title>Taras Shevchenko National University of Kyiv, Ukraine http://www.univ.kiev.ua/en/</title>
        </sec>
        <sec id="sec-19-1-7">
          <title>V.N. Karazin Kharkiv National University, Ukraine http://www.univer.kharkov.ua/en</title>
        </sec>
        <sec id="sec-19-1-8">
          <title>Zaporizhzhya National University, Ukraine http://www.znu.edu.ua/en/</title>
        </sec>
        <sec id="sec-19-1-9">
          <title>Institute of Information Technologies and Learning Tools of the National Academy of Pedagogical Sciences of Ukraine, Ukraine; http://iitlt.gov.ua/en/</title>
        </sec>
        <sec id="sec-19-1-10">
          <title>DataArt Solutions Inc., Russian Federation</title>
          <p>http://dataart.com/
Rigorous Semantics and Refinement for Business Processes . . . . . . . . . . . . .</p>
          <p>Klaus-Dieter Schewe
Smart Learning Environments: a Shift of Paradigm . . . . . . . . . . . . . . . . . . . .</p>
          <p>David Esteban
Tutorial
Systematic Business Process Modeling in a Nutshell . . . . . . . . . . . . . . . . . . .</p>
          <p>Heinrich C. Mayr
Part I: Main ICTERI Papers
Teaching ICT and Using ICT in Education
On the Results of a Study of the Willingness and the Readiness to Use
Dynamic Mathematics Software by Future Math Teachers . . . . . . . . . . . . . .</p>
          <p>Elena Semenikhina and Marina Drushlyak
Model-Based Software System Development
Knowledge-Based Approach to Effectiveness Estimation of Post
Object-Oriented Technologies in Software Maintenance . . . . . . . . . . . . . . . .</p>
          <p>Mykola Tkachuk, Kostiantyn Nagornyi and Rustam Gamzayev
Provably Correct Graph Transformations with Small-tALC . . . . . . . . . . . . .</p>
          <p>Nadezhda Baklanova, Jon Hael Brenas, Rachid Echahed, Christian
Percebois, Martin Strecker and Hanh Nhi Tran
A Study of Bi-Objective Models for Decision Support in Software
Development Process . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .</p>
          <p>Vira Liubchenko
1
3
4
5
21
35
51
62
78
94
Method of Evaluating the Success of Software Project Implementation
Based on Analysis of Specification Using Neuronet Information
Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100</p>
          <p>Tetiana Hovorushchenko and Andriy Krasiy
Machine Intelligence, Knowledge Engineering and Management for
ICT
Calculation Method for a Computer’s Diagnostics of Cardiovascular
Diseases Based on Canonical Decompositions of Random Sequences . . . . . 108</p>
          <p>Igor P. Atamanyuk and Yuriy P. Kondratenko
Synthesis of Time Series Forecasting Scheme Based on Forecasting
Models System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
Fedir Geche, Vladyslav Kotsovsky, Anatoliy Batyuk, Sandra Geche and
Mykhaylo Vashkeba
C-Clause Calculi and Refutation Search in First-Order Classical Logic . . . 137</p>
          <p>Alexander Lyaletski
Principles of Intellectual Control and Classification Optimization in
Conditions of Technological Processes of Beneficiation Complexes . . . . . . . 153</p>
          <p>Andrey Kupin and Anton Senko
ICT in Industrial Applications
A Composite Indicator of K-society Measurement . . . . . . . . . . . . . . . . . . . . . 161</p>
          <p>Kseniia Ilchenko and Ivan Pyshnograiev
Part II: ICTERI Workshop Papers
ITER Workshop Papers
Risk Assessment of Use of the Dnieper Cascade Hydropower Plants . . . . . 204</p>
          <p>Andriy Skrypnyk and Olha Holiachuk
Behavioral Aspects of Financial Anomalies in Ukraine . . . . . . . . . . . . . . . . . 214</p>
          <p>Tetiana Paientko
The Formation of the Deposit Portfolio in Macroeconomic Instability . . . . 225</p>
          <p>Andriy Skrypnyk and Maryna Nehrey
Dynamic Model of Double Electronic Vickrey Auction . . . . . . . . . . . . . . . . . 236</p>
          <p>Vitaliy Kobets, Valeria Yatsenko and Maksim Poltoratskiy
The Multidimensional Data Model of Integrated Accounting Needed for
Compiling Management Reports Based on Calculation EBITDA Indicator 276</p>
          <p>Viktoria Yatsenko
MRDL Workshop Papers
The Hybrid Service Model of Electronic Resources Access in the
Cloud-Based Learning Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 295</p>
          <p>Mariya Shyshkina
Methods and Technologies for the Quality Monitoring of Electronic
Educational Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 311</p>
          <p>Hennadiy Kravtsov
SMSV Workshop Papers
Realisation of ”Black Boxes” Using Machines . . . . . . . . . . . . . . . . . . . . . . . . . 326</p>
          <p>Grygoriy Zholtkevych
An Interleaving Reduction for Reachability Checking in Symbolic Modeling 338
Alexander Letichevsky, Oleksandr Letychevskyi and Vladimir
Peschanenko
Abstracting an Operational Semantics to Finite Automata . . . . . . . . . . . . . 354
Nadezhda Baklanova, Wilmer Ricciotti, Jan-Georg Smaus and Martin
Strecker
The Static Analysis of Linear Loops . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 366</p>
          <p>Michael Lvov and Yulia Tarasich
Defining Finitely Supported Mathematics over Sets with Atoms . . . . . . . . . 382</p>
          <p>Andrei Alexandru and Gabriel Ciobanu
On a Strong Notion of Viability for Switched Systems . . . . . . . . . . . . . . . . . 396</p>
          <p>Ievgen Ivanov
Natural Computing Modelling of the Polynomial Space Turing Machines . 408</p>
          <p>Bogdan Aman and Gabriel Ciobanu
TheRMIT Workshop Papers
Rigorous Semantics and Refinement for Business
⋆
Processes (Abstract)</p>
          <p>
            Klaus-Dieter Schewe1,2
1 Software Competence Center Hagenberg, Austria, kd.schewe@scch.at
2 Johannes-Kepler-University Linz, Austria, kd.schewe@cdcc.faw.jku.at
ICTERI Key Terms. Mathematical Model, Methodology, Formal Method,
Process, Integration
For the modelling of business processes it is necessary to integrate models for
control flow, messaging, event handling, interaction, data management, and
exception handling. In principle, all common business process models such as BPMN
[
            <xref ref-type="bibr" rid="ref14">14</xref>
            ], YAWL [
            <xref ref-type="bibr" rid="ref13 ref29">13</xref>
            ], ARIS [
            <xref ref-type="bibr" rid="ref11 ref27">11</xref>
            ] or S-BPM [
            <xref ref-type="bibr" rid="ref22 ref6">6</xref>
            ] follow such an approach. Though it
is claimed that the models have already reached a high level of maturity, they
still lack rigorous semantics as pointed out in [
            <xref ref-type="bibr" rid="ref1 ref15 ref17 ref21 ref5">1, 5, 15</xref>
            ]. Furthermore, quite a few
aspects such as data management, interaction and exception handling have only
been dealt with superficially as pointed out in [
            <xref ref-type="bibr" rid="ref12 ref28">12</xref>
            ].
          </p>
          <p>
            The first concern regarding rigorous semantics has been discussed in detail
by B¨orger in [
            <xref ref-type="bibr" rid="ref18 ref2">2</xref>
            ] for BPMN, which led to an intensive investigation of BPMN
semantics on the grounds of Abstract State Machines (ASMs, [
            <xref ref-type="bibr" rid="ref20 ref4">4</xref>
            ]), in particular
for OR-synchronisation [
            <xref ref-type="bibr" rid="ref19 ref3">3</xref>
            ]. The monograph by Kossak et al. defines a rigorous
semantics for a large subset of BPMN leaving out some ill-defined concepts [
            <xref ref-type="bibr" rid="ref24 ref8">8</xref>
            ].
          </p>
          <p>
            The second concern can be addressed by means of horizontal refinement.
On grounds of ASMs necessary subtle distinctions and extensions to the control
flow model such as counters, priorities, freezing, etc. can be easily integrated in
a smooth way [
            <xref ref-type="bibr" rid="ref12 ref28">12</xref>
            ]. Conservative extensions covering messaging can be adopted
from S-BPM [
            <xref ref-type="bibr" rid="ref22 ref6">6</xref>
            ], while events in BPMN have been handled in [
            <xref ref-type="bibr" rid="ref23 ref7">7</xref>
            ]. For the event
model it is necessary and sufficient to specify what kind of events are to be
observed, which can be captured on the grounds of monitored locations in ASMs,
and which event conditions are to be integrated into the model. Extensions
concerning actor modelling, i.e. the specification of responsibilities for the execution
of activities (roles), as well as rules governing rights and obligations lead to the
integration of deontic constraints [
            <xref ref-type="bibr" rid="ref10 ref26">10</xref>
            ], some of which can be exploited to simplify
the control flow [
            <xref ref-type="bibr" rid="ref25 ref9">9</xref>
            ]. In this way subtle distinctions regarding decision-making
responsibilities in BPM can be captured.
⋆ The research reported in this paper was supported by the Austrian
Forschungsfo¨rderungsgesellschaft (FFG) for the Bridge Early Stage project
“Advanced Adaptivity and Exception Handling in Formal Business Process Models”
(adaBPM) under contract 842437.
          </p>
          <p>In the talk a glimpse of the rigorous, ASM-based semantics for business
processes is presented. The focus is on the control flow with specific emphasis on
priority handling. This is followed by a discussion of horizontal refinement
focusing on the introduction of disruptive events and associated exception handling. A
simplified example capturing the effects of external change to a running process
is used for illustration.
Smart Learning Environments: a Shift of Paradigm</p>
          <p>David Esteban1
1 TECHFORCE, Vía Augusta, 2bis planta 5ª E-08006 Barcelona, Spain
Abstract. The incorporation of Information and Communication Technologies
(ICT) as a supporting mechanism in educational processes has already been
proved as an important driver in reinforcing both teaching and learning. The
extensive development of Learning Management Systems (LMS), software
platforms aimed at supporting and articulating e-learning, education courses and
training programs, is already backed by a relevant ICT industry, with significant
market penetration. The emergence of the new concept of Smart Learning
Environments (SLEs) is shifting the main focus of LMSs on courseware towards a
more efficient and effective approach focused on teaching and learning
processes, thus in the students themselves and in the teachers as key players. The
evolving concept of SLEs encompasses blending educational technologies with
appropriate considerations and guidance developed by pedagogical and
educational neuroscience domains, thus opening up room for interesting scientific and
technological challenges.
Systematic Business Process Modeling in a Nutshell</p>
          <p>Heinrich C. Mayr1
1Alpen-Adria-Universität Klagenfurt,
Universitätsstrasse 65-67 Klagenfurt, 9020, Austria</p>
          <p>Heinrich.Mayr@aau.at
Abstract. In-depth business process management is crucial for any institution
and enterprise in a competitive world. Although this insight is by no means
new, the daily practice draws another picture: Certainly, many enterprises have
defined their overall strategy including IT issues at least roughly, and, based
here on, have documented their business processes somehow. Rarely however,
do they manage their business processes comprehensively in the sense of
covering analysis, design, measurement, continuous optimization, and IT support.</p>
          <p>The key prerequisite for allowing such comprehensive handling of business
processes is to describe these processes transparently and completely, using a
modeling language that is appropriate for the particular context including all
stakeholders concerned.</p>
          <p>The aims of this tutorial, therefore, are threefold: (1) the participants will learn
about the fundamentals of business processes and their contexts; (2) the key
features of popular business process modeling languages like Adonis and
BPMN; and (3) guidelines for selecting an appropriate modeling approach
including the customization to the given environment.</p>
          <p>Intended audience: Practitioners and researchers who are interested in a
systematic approach to business process management, and have basic knowledge
in modeling and information systems engineering.</p>
          <p>Keywords. Business process fundamental, business process context, business
process modeling language, selection of the modeling approach, customization
Key Terms. Process, ProcessPattern, Technology, Methodology, Model
Using ICT in Training Scientific Personnel in Ukraine:</p>
          <p>Status and Perspectives</p>
          <p>Aleksandr Spivakovsky, Maksim Vinnik and Yulia Tarasich
Kherson State University, 27, 40 rokiv Zhovtnya St., 73000 Kherson, Ukraine
{Spivakovsky, Vinnik, YuTarasich}@kspu.edu
Abstract. Today an enormous amount of problems in building a system of
efficient education and science is on the discussion agenda in Ukraine. A
decrease in the number of scientists in the country has been observed in the last
15 years. At the same time, the amount of postgraduate students and people
aiming at obtaining their doctorate is increasing. Notably, similar indicators are
also observed in the majority of post-soviet countries. One complicating factor
is that the system of scientific personnel training in Ukraine is very restrictive
and closed. The proportion of research results published using a free access
scheme to the overall bulk of publications is still very small, in particular if
compared to the level of ICT development. Therefore, a major part of the
publications still remains inaccessible from the outside. In this study we
investigate the openness and accessibility of the preparation of the academic
staff in Ukraine. As a result we come up with a proposal of requirements to the
ICT infrastructure in this area.</p>
          <p>Key Terms: ICT Infrastructure, Research.</p>
          <p>''If it's not on the Web, it doesn't exist at all''</p>
          <p>Sarah Stevens-Rayburn &amp; Ellen N. Bouton, 1997
1 Introduction
The main catalyst for socio-economic development of a state potential is the ability to
create, collect, and effectively manage knowledge that is comes out from the best
scholarly research practices. The countries which have made it to their development
strategy and implemented the effective interaction with the business enjoy TOP
ratings in the World rankings. In the age of information technologies, it takes one not
years, but rather days to bear the bell of scientific research and excel the competitors.
The companies which are the first in the market are more likely to benefit from a
positive effect caused by the introduction of new knowledge. Globalization is
adjusting the cooperation between science and industry. More and more funds are
invested in scientific research and development to capture the leadership in the
market. A modern country's development is stimulated by the transition from a
resource-based economy to hi-tech. There is an opportunity to create “intellectual
dollars” without any resource, but people. The results of intellectual work become a
hard currency. For example, Japan, though it had no natural resources, managed to
become the leader in world's economy. The monetary value of the biggest hi-tech (IT)
companies is at a scale of the budgets of some developed countries (Apple – $ 711
billion, Microsoft – $ 349 billion, Google – $ 365 billion).</p>
          <p>
            The Open Science (OS) movement gains popularity in the world of clerisy, aiming
to make research results and source data accessible to public at all levels. However,
there is a conflict between the desire of scientists to have access to shared resources
and make profit by using these resources [
            <xref ref-type="bibr" rid="ref1 ref17">1</xref>
            ]. In recent years, many governments try
to impose the policy of openness regarding scientific knowledge, especially, if it is
funded with public money. One way is the enforcement of providing open access to
the results of all research projects performed at public expense. An indicative example
is the US, which grant annually about $ 60 billion for research. In 2008, the US
Congress imposed the obligation to grant free access in a year after the first
publication to all the research papers based on the studies conducted by the National
Institute for Health (which receives circa the half of the total public funding for
science). Similar measures are now considered by many other countries.
          </p>
          <p>Today, a lot of research in Ukraine is devoted to the problems of higher education
and, in particular, the use of ICT for training students, creating information and
communication environments in the universities, etc. However, in the scholarly
literature insufficient attention is paid to the development of information and
communication models of interaction with ІCT in academic staff training. Moreover,
today we are talking about the need for openness and accessibility of scientific
activity, whereas a substantial part of the scholarly output never reaches its reader
within and even more outside the professional academic community. This problem is
particularly acute in the post-soviet countries. Regionalism of entire areas in science,
convention, low connection with contemporary scientific trends, low level of foreign
language knowledge by scientists, lack of self-developing scientific community, low
competition with other countries, lack of motivation, poor funding, brain drain, and a
number of other factors result in the continuing archaism of scientific brainpower
training in Ukraine.</p>
          <p>Scientometrics is rapidly developing nowadays. Using information technology
allows creating new services for the development of scientific and research activity.
Many global companies invest billions of dollars in services to support research
activity, thereby creating a serious market not for the research results but for the
research process support. Herewith the trend shifts toward commercial projects. The
examples of such companies are Apple, Microsoft, Google, Elsevier, Thomson
Reuters, not to mention many others. The most outstanding services with rapidly
growing impact are Google Scholar, Scopus, Orcid, Academia.edu, Research Gate,
Mendeley, arXiv.org, cs2n, Epernicus, Myexperiment, Network.nature,
Sciencecommunity. These services contribute to satisfying the needs of the scientific
community. In fact, these positively influence scientific and technical progress and
create a new paradigm of scientific research. A big number of the recently created
scientometric services allow assessing the relevance of the research results by a
scientist, the number of his publications, citations, storage, etc. Having these
measurements at hand opens up new opportunities and prospects. Our time is
characterized by the high rates of the accumulation of new knowledge, in particular in
А
С</p>
          <p>E
B</p>
          <p>D
Fig. 3. The RBD of the fault-tolerant
system
On the basis of developed binary
SAM of the fault-tolerant system,
which consists of set of formal
parameters (Fig. 4), SV
components and failure condition
(Fig. 5), the tree of modification
rules of state vector (Fig. 6),
which is the input to the software
module ASNA, the graph states
and transitions was obtained in the
automatic mode (Fig. 7).
Fig .5. State vector components and failure condition</p>
          <p>Basing on the obtained graph of states and transitions the software module ASNA
formed mathematical model of the system as a system of Chapmen - Kolmogorov
differential equations. After its solving the probability of being in every possible state
was obtained. Probability of system being in operable state is 0.9894, and the
probability of failure is equal to:</p>
          <p>Qf = 1 - 0,9894 = 0,01061
λA</p>
          <p>ABC</p>
          <p>DE
λE λD
λB
λC</p>
          <p>λD
BCDE
λE</p>
          <p>λA
ACD λC</p>
          <p>λE
λA
ABD</p>
          <p>λE λD
λB
ABCE λC
λE
λC
λB
λB
λA
λB
λA
ABC λC
λD</p>
          <p>CDE
λD
λC</p>
          <p>BDE
ADE
λE
λB
λA
λD
λA
ABE λB
λE
ABD
λD
DE
λD</p>
          <p>λE
λA</p>
          <p>BCD λB
ACD
λA
λD
λB</p>
          <p>BCE
ACE
λC
λB
λA
λC
λD
λE
CE</p>
          <p>BE
AE
λC
λB
λA
CD
λC
λE</p>
          <p>E
λE</p>
          <p>SF</p>
          <p>
            On the basis of the graph of states and transitions according to developed algorithm,
it was determined that after simultaneous failure of modules E and D the system fails
in general. Next, other two combinations which also lead to failure of the whole system
are ACE and BCE. Thus, these three combinations make the MCS. The next stage was
the determining of the values of the probability of each of these combinations.
Substituting logical expression of MCS DE: ((V4 = 0) AND (V5 = 0)) instead of failure
condition the MCS value of probability simultaneous failure of combination of modules
E and D was obtained, which is QDE = 0,009. Similarly, substituting logical expression
of MCS ACE and BCE instead of failure condition we get: QACE = 0,00084; and QBCE
= 0.00084. The calculated MCS is shown in Table. 1.
Validation of the
developed method. To
validate the developed
method it was
implemented the a
fault tree building for
the system (Fig. 8)
according to the
approach [
            <xref ref-type="bibr" rid="ref24 ref8">8</xref>
            ] and the
values of the
probability of failures
for each MCS were
calculated. It was
considered that the
results obtained by
fault tree are accurate
and they were
compared with results
which are shown in
Fig.8. Fault tree Table 1.
          </p>
          <p>The validation was
performed using
specialized software suite RAM Commander by ALD Service. For RBD the fault tree
was set up (Fig. 8) and MCS were obtained by tools of RAM Commander and are
shown in Fig. 9.</p>
          <p>The comparison shows that the calculated values of MCS, which were obtained from
fault tree using software suite RAM Commander coincide with the values obtained
from the graph of states and transitions with the split failure state using binary SAM.
The developed approach (Fig. 2) allows us to get the MCS in automatic mode without
fault tree construction.</p>
          <p>Expanding the Functionality of the Program ASNA for the</p>
          <p>Safety Analysis of CTSCA</p>
          <p>For building complex models, which are focused on determination of the reliability
and safety indexes it is most advisable to take as a basis the graph of states and
transitions with split state of catastrophic failure and method for its automated
construction using binary SAM. However, the biggest problem for the designer, in this
case, is the construction of the binary SAM because its formation requires from the
developer not only the deep knowledge of the nuances of functionality of designed
CTSCA but also thorough knowledge about techniques of construction the formalized
graph of states and transitions that is the whole direction in complex systems designing.</p>
          <p>
            Therefore, the next urgent task is to automate the construction of binary SAM-based
graphical representation of the system as a RBD. This will speed up the development
of SAM, reduce the time cost in degree and obtain both reliability and safety indexes.
Principles of this automation were laid in works [
            <xref ref-type="bibr" rid="ref12 ref15 ref28">12, 15</xref>
            ]. At the same time, we note
that this approach narrows the class of the analyzed systems because it does not allow
us to analyze complex technical systems that are described by queuing systems,
flowcharts, etc. behavior algorithm.
          </p>
          <p>
            According to approach [
            <xref ref-type="bibr" rid="ref12 ref28">12</xref>
            ] the visualization software for RBD of technical system,
which makes it possible the automatic construction of graphic images of flow diagram
of technical systems and the formation of conditions of their functioning and failure,
was developed. Using the developed software the information about the system is
transmitted as input to the ASNA software for further calculations of reliability indexes
accordingly to the number of elements in the node, the number of renewals and
maintenance crews, time range, intensity of failures and recoveries for each of elements
of analyzed system.
          </p>
          <p>
            In order to extend the functionality of the ASNA software for safety analysis of
CTSCA it is needed to combine binary SAM methodology with the approach [
            <xref ref-type="bibr" rid="ref12 ref28">12</xref>
            ]. It is
necessary to modify the SAM as follows:
 Every element input in the RBD is accompanied by the creation the next set of SV
components, the number of elements corresponds to the number of components:
Item1, Item2, … ,Itemi,… → V11, V21, … , Vi1, …


          </p>
          <p>The initial value of each component is equal to one: Vi1=1;
Type of connection of RBD elements (serial, parallel, combined) is given by the
inoperable condition
If the limited number of renewals of system is planned, for each item is added
another SV component – counter of repairs:</p>
          <p>→ V12, V22, … , Vi2, …</p>
          <p>The initial value of each component is equal to zero: Vi2=0
If the number of renewals is unlimited, the additional component isn’t added;
Each RBD element is assigned to line of binary SAM as follows:</p>
          <p>Event Condition FCIT FCPAT MRSV
Failure of module і Vi1=1 i 1 Vi1=0
If the system is renewable, in addition to each RBD element, another line is
assigned to binary SAM as follows:</p>
          <p>Event Condition FCIT FCPAT MRSV
Repair of module і (Vi1=0) AND µi 1 Vi1=1
(Vi2&lt;RCi) Vi2= Vi2+1
 Parametres of each element (failure rate - i, the intensity of repair - i, the number
of repairs - RCi etc.) is transmitted to set of formal parametres;
 Limited values of each RBD element repair, the number of repair crews, repair
priority are transmitted to set of formal parametres;
 Inoperable conditions are transmitted to SAM and serves to filter the
operablebodied and inoperable states.</p>
          <p>
            Thus all components of SAM can be automatically formed. Generated data can be
represented as a file that is sent to ASNA software module as input data. ASNA
software module enables automated obtaining of the graph of states and transitions with
split failure state. Basing on the graph of states and transitions ASNA software makes
it possible to assess reliability. CutSetDefiner software, basing on the graph of states
and transitions, can generate MCS and basing on MCS through software [
            <xref ref-type="bibr" rid="ref16">16</xref>
            ] we can
automatically get the fault tree.
5
          </p>
          <p>Conclusions
1. Split of critical failure state in graph of states and transitions, in contrast to the
known approaches, allows estimation of reliability and safety indexes, that makes the
impact of maintenance strategies on safety and reliability, impact of the fault
tolerance on safety to be considered. This will increase the accuracy (certainty) of
efficiency indexes estimation of complex technical systems for critical application.
2. Minimal cut sets obtaining on the basis of the graph of states and transitions allows
taking into account the interrelations of accidents directly from the analysis of system
states for identification weaknesses. It gives only reasonable means for providing
fault tolerance that reasonably reduces the cost of improving the system.
3. Using binary structural-automatic model allows automated obtaining of split critical
failure state and reducing time costs for building the graph of states and transitions.
4. Risk reduction factor was introduced for quantitatively assess of the efficiency of
improving safety by improving reliability by introducing redundancy in critical
elements of complex technical systems for critical application.
5. Fault tree building from the graph of states and transitions basing on minimal cut
sets takes into account the behavior of complex system that is not available when
using static and dynamic fault trees
6. The combination of binary structural-automatic model and method of automated
constructing of graph of states and transitions basing on reliability block diagram
makes it possible to automate the procedure of building structural-automatic model
of fault-tolerant renewable complex technical systems for critical application and
reduce time costs by more than degree.
Scenario-Based Markovian Modeling of Web-System
Availability Considering Attacks on Vulnerabilities
Vyacheslav Kharchenko1, Yurij Ponochovny2, Artem Boyarchuk1 and Anatoliy</p>
          <p>Gorbenko1
1 National Aerospace University KhAI, Kharkiv, Ukraine</p>
          <p>V.Kharchenko@khai.edu
2 Poltava National Technical University named after Yurij Kondratyuk, Poltava, Ukraine
pnch1@rambler.ru
Abstract. In the paper we simulate web-system availability taking into account
security aspects and different maintenance scenarios. As a case study we have
developed two Markov’s models. These models simulate availability of a
multitier web-system considering attacks on DNS vulnerabilities in additional to
system failures due to hardware/software (HW/SW) faults. Proposed Markov’s
model use attacks rate and criticality as initial simulation parameters. In the
paper we demonstrate how to estimate these parameters using open
vulnerability databases (e.g. National Vulnerability Database). We also define
different vulnerability elimination (VE) scenarios and examine how they affect
system availability.</p>
          <p>Keywords: web-system availability, security, vulnerability, Markov’s models,
scenario of vulnerability elimination</p>
          <p>Key terms. MathematicalModeling, MathematicalModel, SoftwareSystems
1 Introduction</p>
          <p>
            Efficient implementation and operation of multitier web-systems using COTS
components depend on accuracy of security assessment and quality of attacks
prevention and recovery activities. Security of web-system can be estimated by
analyzing web-components vulnerabilities and predicting attacks affecting system
availability and other security attributes. System availability and accessibility of the
provided ser-vices depend on the used maintenance strategy. This strategy can
implement various vulnerability prevention and elimination scenarios [
            <xref ref-type="bibr" rid="ref1 ref17">1</xref>
            ]. Thus,
assessing web-systems availability taking into account both system failures due to
HW/SW faults, and hacker attacks on components vulnerabilities is important.
          </p>
          <p>
            To estimate system availability and security researchers develop various simulation
models [
            <xref ref-type="bibr" rid="ref1 ref17 ref18 ref2">1, 2</xref>
            ]. Most of them are based on attack tree analysis [
            <xref ref-type="bibr" rid="ref19 ref20 ref3 ref4">3,4</xref>
            ], Markov’s [
            <xref ref-type="bibr" rid="ref21 ref22 ref5 ref6">5,6</xref>
            ] and
semi-Markov’s chains [
            <xref ref-type="bibr" rid="ref23 ref24 ref7 ref8">7,8</xref>
            ] or use of Petri nets [
            <xref ref-type="bibr" rid="ref10 ref25 ref26 ref9">9,10</xref>
            ] as a mathematical apparatus.
However, known models do not explicitly consider attacks on system vulnerabilities
causing inaccessibility of the provided services (accessibility vulnerabilities) and do not
take into account different security policies and vulnerability elimination strategies.
          </p>
          <p>
            In the paper we analyze web-system availability considering failures caused by
HW/SW faults as well as attacks on system vulnerabilities. With this purpose we
propose and examine a set of Markov’s availability models implementing different
scenarios of vulnerability elimination. This paper continues research described in [
            <xref ref-type="bibr" rid="ref22 ref6">6</xref>
            ]
using scenario-based approach.
          </p>
          <p>The rest of the paper is organized as follows. In the second section we suggest a set
of scenarios to assess web-system availability taking into account different vulnerability
elimination procedures. In the third section we discuss a technique of estimating input
parameters of Markov’s models by use of information about software component
vulnerabilities from the open vulnerability databases. The forth section presents a case
study and the set of Markov’s models and also examines simulation results.
2 The Scenario-Based
Modeling with Regards
Elimination</p>
          <p>Approach to
to System</p>
          <p>Web-System
Vulnerabilities</p>
          <p>Availability
and their</p>
          <p>
            Attacks on vulnerabilities of web-systems can be simulated using Markov’s models
[
            <xref ref-type="bibr" rid="ref21 ref22 ref23 ref5 ref6 ref7">5-7</xref>
            ]. However, for that we should take into account that parameters of the
vulnerabilities (numbers and types) are changed as a result of elimination and patching
procedures.
          </p>
          <p>In the Fig. 1 we propose a set of common state-transitional models capturing
different attack and recovery scenarios. The scenarios are differed by a number of
attacked vulnerabilities: one (a-f) or several (g); with (b-g) or without (a) vulnerability
elimination; with vulnerability elimination after system been successfully attacked (b-d)
or during (e,f) preventive maintenance actions.</p>
          <p>We have marked model states as following: double circles correspond to up-states,
single line marked circles correspond to maintenance states, thick line marked circles
correspond to down-states after attacks.</p>
          <p>The simplest scenario is shown in Fig. 1,а. After successful attack a web-system is
recovered (e.g. rebooted) without vulnerability elimination. However not all attacks can
be successful and lead to web system unavailability. This is why we consider two
transitions from up-state S0: the first transition with the rate attack*Da leads to down
(unavailable)-state Sd; the second one with the rate attack*(1-Da) returns back to
upstate S0 (Da is a probability of attack to be successful).</p>
          <p>The second scenario (Fig. 1,b) illustrates vulnerability elimination during system
recovery after successful attack. We assume that during recovery action it is possible to
eliminate from 0 to all (nv) vulnerabilities. Hence, web-system may return from the
down-state Sd to the initial state S0 without vulnerability elimination with the rate
′ a*(1-Dp), where Dp is a probability of successful recovery and vulnerability
elimination, or may transit to the next up-state Su with the rate ′ a*Dp.
ilty
tuho lavo irae</p>
          <p>b
iw rem lvun
t
s
te
i
i
l
i
b
a
r
e
n
l
u
v
l
a
v
o
m
e
r
e
h
t
h
t
i
W
e
v
i
t
n
e
v
e
r
p
h
t
i
W
l
a
r
e
v
e
s
on se
s i
k it
ttcaa ilrab
ith len
W vu</p>
          <p>S0</p>
          <p>nv
S0
S0
S0
S0
Sp
S0
Sp</p>
          <p>S0
Sd
Sd
Sd</p>
          <p>Sd
Sd
Sd
Sd
Sd
Sd
Sd</p>
          <p>nv-1
Su
Su
Su
Su
Sp
Su</p>
          <p>Sp
Su
Sd
Sd
Sd</p>
          <p>Sd
Sd</p>
          <p>1
Su
Su
Su
Su
Sp
Su</p>
          <p>Sp
Sd</p>
          <p>Su</p>
          <p>Sd
Sd
Sd
Sd
Sd
Sd
0
Su
Su
Su
Su
Su
Su
a)
b)
c)
Fig. 1. Graph models of scenarios of web-system availability considering different options of
vulnerability elimination</p>
          <p>The third scenario (Fig. 1,c) describes graduate vulnerability elimination only after
successful attacks on these vulnerabilities. In this scenario the total number of
vulnerabilities in the system may be unlimited nv → ∞.</p>
          <p>The step by step vulnerability elimination is described by the next scenario (Fig. 1,d).
In this case it is assumed that restart of web-system is possible without elimination of
vulnerability which was attacked.
3 Estimation of Input
Availability Models
3.1</p>
          <p>Parameters for</p>
          <p>Markov’s</p>
          <p>Web-System</p>
          <p>According with the fifth scenario (Fig. 1,e) vulnerabilities can be detected and
eliminated from the system only during the periodic maintenance actions (i.e. security
audits) only. After the successful attack a web-system is restarted or reboot without
vulnerability elimination. Vulnerabilities can be detected and eliminated from the
system only during periodic security audits. The probability of eliminating the i-th
vulnerability is equal to αi, Σαi = 1.</p>
          <p>The sixth scenario (Fig. 1,f) assumes that vulnerabilities can be detected and
eliminated from the system both after successful attacks or during periodic security
audits. The seventh scenario takes into account possibility of attacks on several
vulnerabilities (Fig. 1,g). The scenario describes sequential chains of attacks on sever-al
(four, in our example) services of a web-system. In this case an intruder continues to
attack the next services. After successful attack a web-system can transit to a new
upstate where vulnerabilities are eliminated from the system or can return back to the
initial state by system restarting or rebooting.</p>
          <p>Described set of scenarios is not complete. This set includes some basic scenarios.
However, other scenarios can be developed considering different procedures of
maintenance and vulnerability elimination or patching.</p>
          <p>In this section we discuss how parameters of Markov’s models simulating
websystem availability can be estimated using existing vulnerability databases like NVD.</p>
          <p>
            The whole set of vulnerabilities stored in NVD can be downloaded as an XML file
«NVD/CVE XML Feed with CVSS and CPE mappings (version 1.2)» [
            <xref ref-type="bibr" rid="ref11 ref12 ref27 ref28">11,12</xref>
            ]. Then we
need to select those vulnerabilities of Web-system components (DNS-server,
HTTPserver, application server, etc.) affecting system availability. It is can be done by
analyzing vulnerabilities availability impact and vector of access using, for instance,
common vulnerability scoring system (CVSS) [
            <xref ref-type="bibr" rid="ref13 ref29">13</xref>
            ] provided by NVD:
          </p>
          <p>- Availability impact, A, which can be equal one of three fuzzy values “None” (N),
“Partial” (P) and “Complete” (C);
- Vector of access, value “Network” (N).</p>
          <p>For example, Table 1 presents a subset of vulnerabilities detected during 2013 and
causing unavailability of DNS (CVSS_vector – contains – AVμN, AμC и AμP;
ns1:descript – contains – DNS (an example for analysis attacks on DNS) including their
publishing dates and score.
3.2</p>
          <p>Estimation of Attack Rates</p>
          <p>In order to parameterizes state-transition models we need to evaluate a rate of the
attacks exploiting system vulnerabilities.</p>
          <p>This rate obviously depends on different factors including number of system
vulnerabilities, their criticality, availability impact and vector of access. However,
vulnerabilities define only the capability of a system to be attacked. On the other hand,
unlike random system failures, vulnerabilities are exploited by various intended (hacker,
computer criminals, industrial espionage, insiders, etc.) and unintended (viruses, worms,
malware, etc.) threat agents.</p>
          <p>name
CVE-2013-0198
CVE-2013-2266
CVE-2013-2494
CVE-2013-1152
CVE-2013-2052
CVE-2013-2053
CVE-2013-2054
CVE-2013-4854
CVE-2013-4115
CVE-2013-5479
CVE-2013-5480</p>
          <p>Motivation of intended threat agents is also depended on the system itself (its value
and interest for the attacker). Last two factors are really difficult to define quantitatively.
Thus, in the paper we propose to define the attack rate by the average per year
frequency of vulnerability disclosure in the system components.</p>
          <p>Criticality of attack is determined as an average value of basic CVSS estimation. We
propose the following technique to estimate attack rate:</p>
          <p>1) development of availability block diagram (ABD) of web-systems as a
sequentially-parallel connection of components influencing on accessibility (similar to
RBD);
2) extraction from NVD the vulnerability subsets for all components of ABD;
3) calculation of average per year frequency of vulnerability disclosure in these
subsets;</p>
          <p>4) determination of attack rate as the maximum of these frequencies of vulnerability
disclosure;</p>
          <p>5) calculation of attack criticality as an average value of basic CVSS estimation for
selected set per year.</p>
          <p>According with Table 1, average attack rate on DNS vulnerabilities causing
unavailability could be estimated in 2013 as 1,26*10–3 1/h while the average criticality
equals 6,75.</p>
          <p>Route
DNS</p>
          <p>DHCP</p>
          <p>Route
mudns</p>
          <p>ladns
4 Web-System Availability
Elimination Scenarios</p>
          <p>Models for Different Vulnerability
4.1 Initial Model and its Parameters</p>
          <p>Let us examine a web-system based on three network services: DNS, DHCP and
Routing. Reliability block diagram (RBD) and Markov’s model (the marked Markov’s
chain) of the web-system are shown in Fig. 2.</p>
          <p>Fig. 2. Reliability block diagram and Markov’s model of the web-system without considering
system vulnerabilities</p>
          <p>
            The RBD consists of three consequently connected components and failure of any
components causes failure (unavailability) of the system. In this section we study two
availability models taking into account attacks on DNS vulnerabilities and different
maintenance operations including security audits [
            <xref ref-type="bibr" rid="ref23 ref7">7</xref>
            ]. The first model (MA-1)
corresponds to scenario with vulnerability elimination during security audits only
(Fig. 1,e). The second one (MA-2) implements scenario with vulnerability elimination
after successful attack on a system and also during security audits (Fig. 1,f).
          </p>
          <p>Initial values of model parameters are presented in Table 2. The models itself have
been implemented as Matlab programs.
4.2</p>
          <p>The Model MA-1</p>
          <p>This model describes a web-system with attacks on DNS vulnerabilities and
periodic maintenance activities (security audits) including detection and elimination
of vulnerabilities without complication of code (ladns =const).
mudns</p>
          <p>ladns</p>
          <p>Sn+1
j
αj</p>
          <p>q*muprof
mureboot</p>
          <p>S10
S11
nv–1
qnv–2*p</p>
          <p>nv
1-∑αj
S1
S2</p>
          <p>S3
mudns</p>
          <p>ladns
mudhcp</p>
          <p>ladhcp
muroute
laroute</p>
          <p>Fig. 3. Marked Markov’s graph for МА-1</p>
          <p>Marked Markov’s graph is shown on Fig. 3. As during these activities it is possible to
detect and eliminate more than one vulnerability [1…nv], we use a special parameter αj
which defines probability of detection of j-th (j  [1…nv]) vulnerabilities. Apparently,
Σαj = 1, and values α1, α2,… αj,… αnv are distributes on discreet law. For calculation
of geometrical distribution law αj was used with parametersμ р=α1=0.7 (probability of
detection of the single vulnerability) and q=1–р=0.3 (Table 3).</p>
          <p>Initially (state S0) web-system works considering failures and recovering of DNS,
DHCP и Routing services (states S1- S3). After attack on DNS (transition to state S5
with the rate d1dns*laatdns) the system fails and can be recovered by restart without
vulnerability elimination with rate mureboot. Periodically maintenance activities are
performed (state S4) during which 0, 1,…nv vulnerabilities can be eliminated
(transitions from state S4 to states S0, S4… Sn). These transitions are weighted using
parameter αj*muprof. Further process is continued in the same way (states Sn…Sn+3).
1
0.998
0.996
t)0.994
(
A
0.992
1
)(t0.96
A0.95
3.5</p>
          <p>4.5
2.5
t, hours</p>
          <p>5
x 104
Fig. 4. Diagram of dependency of availability function for the model МА-1 on different
probabilities α1
mureboot =0.05
mureboot =0.1
mureboot =0.5
mureboot =1
mureboot =2</p>
          <p>2.5
t, hours
3.5
4.5</p>
          <p>5
x 104
Fig. 5. Diagram of dependency of availability function for the model МА-1 on different
recovery rate after attack on vulnerabilities, mureboot</p>
          <p>The research results of availability function depending on parameters р=α1 and
mureboot are shown on Fig. 4 and Fig. 5.</p>
          <p>The greater value α1 causes more fast transition of the function A(t) to stationary
state (Fig. 4). A value of mureboot influences on a value of availability function
minimum, location of minimum on the time axis and time of transition to stationary
state (Fig. 5). If mureboot=2 (1/hour) availability function minimum equals 0,9953 for
t=17 hours; if mureboot=0.05 (1/hour) availability function minimum equals 0,9103 for
t=119 hours.</p>
          <p>The model МА-2</p>
          <p>This model describes scenarios whish in addition to MA-1 assumes detection and
elimination of vulnerabilities both during security audit and right after attack (without
complication of code (ladns =const). Marked Markov’s graph is shown on Fig. 6.
S0
S1
S2</p>
          <p>S3
murecovery*
*(1-d2p)
murecovery*
*d2p
q*muprof</p>
          <p>S10</p>
          <p>an-1*muprof
murecovery*
*(1-d2p)</p>
          <p>murecovery*</p>
          <p>S11 *d2p
d1dns*laatdns
S6
S7
S8</p>
          <p>S9</p>
          <p>After attack on DNS and transition to state S5 with rate d1dns*laatdns system fails
and can be recovered by restart without eliminating vulnerability with the rate (1–
d2p)*murecovery or with elimination with the rate d2p*murecovery.</p>
          <p>The results of availability function analysis depending on parameters d2p and laprof
are shown on Fig. 7 and Fig. 8. The increasing of probability of vulnerability
elimination d2 during maintenance activities causes more fast transition of the function
A(t) to stationary state (Fig. 8). Changing the availability function depending on the rate
of maintenance laprof is dual. On the one hand the rare maintenance activities are
carried on the more minimum of availability function on non-stationary phase. On the
other side the more often maintenance activities are carried on the faster the function
transits to stationary state (Fig. 8).
d2p =0
d2p =0.1
d2p =0.2
d2p =0.5
d2p =0.7
d2p =1
laprof =4.57e-2
laprof =4.57e-3
laprof =4.57e-4
laprof =4.57e-5
laprof =4.57e-6
1
0.998
0.996
0.994
)0.992
(t
A
0.99
0.988
0.986
0.984</p>
          <p>0
1
0.99
0.98
0.97
)
(tA0.96
0.95
0.94
0.93
t, hours</p>
          <p>2.5
x 104
Fig. 7. Diagram of dependency of availability function for the model МА-2 on different
probabilities of vulnerability elimination after attack d2p
Fig. 8. Diagram of dependency of availability function for the model МА-2 on rate of
maintenance laprof
4.4</p>
          <p>Combining of the Models МА-1 and МА-2</p>
          <p>The scenarios corresponding to the models MA-1 and MA-2 can be superposed to
increase availability due to increasing of minimum and duration of system transition
to the stationary state of availability function. To combine these two scenarios we
have developed a set of Matlab programs. Filing of coefficient matrixes was done
according with the same initial data (Table3). To solve systems of
KolmogorovChapman’s differential equations the method ode15s for time span [0…20000] hours.
The results of solving are shown on the Fig. 9.
МA-2
model without attacks
МA-1
combination of scenarios
1
0.998
0.996
0.994
0.992
)
t
(A0.99
0.988
0.986
0.984</p>
          <p>2
x 104</p>
          <p>Fig. 9. Combining of the models MA-1 and MA-2 (solid line)</p>
          <p>According to Fig. 9, the vulnerability elimination scenario MA-1 is better to use till
tswitch =750 hours, after this time the scenario MA-2 ensures better availability.
Hence at the beginning recovering a system after attack (without vulnerability
elimination) is preferable. Then, taking into account increase of the number of failures
caused by attacks other scenario (when vulnerabilities are detected and eliminated
both after attacks and during maintenance) becomes preferable. It allows increasing
the value of availability from 0.984 (MA-2) to 0.988 (MA-1) and decreasing time
transition to stationary state from 20000 (MA-1) to 3000 (MA-2) hours.
5 Conclusions</p>
          <p>We analyzed a set of web-system behavior scenarios in conditions of attacks on
component vulnerabilities. Quantitative assessment and research of availability for
such systems can be based on Markov’s models using statistic data about
vulnerabilities contained in open databases and described sequence of evaluating of
attacks rates and criticality.</p>
          <p>We proposed and discussed two models of web-system availability considering
attacks on DNS vulnerabilities and different scenarios of vulnerability elimination.
There is possibility and reasonability of scenario changing taking into account values
of availability function allowing increase minimum one at the non-stationary stage
and decrease time of transition to stationary state. This approach allows selecting VE
scenario to improve resilience of web-system.</p>
          <p>The future research efforts may be concentrated on development of integrated
strategies for maintenance and security policies selection taking into account physical,
design and interaction faults, and implementation of dynamically reconfigurable
weband cloud-systems with embedded monitor and solver to select the optimal strategy of
maintenance.</p>
          <p>Besides, other types of the vulnerabilities for confidentiality and integrity issues
and more detailed model taking into account routing processes can be researched.
References</p>
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