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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Time Multipliers in Project Effectiveness Models for Ensuring the Survivability of Information Systems⋆</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Yuriy Syvytsky</string-name>
          <email>ys@intecracy.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Viktor Shevchenko</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Institute of Software Systems of the National Academy of Sciences of Ukraine</institution>
          ,
          <addr-line>40/5 Akademik Hlushkov ave., 03187 Kyiv</addr-line>
          ,
          <country country="UA">Ukraine</country>
        </aff>
      </contrib-group>
      <fpage>425</fpage>
      <lpage>436</lpage>
      <abstract>
        <p>The paper is devoted to the topical issue of the development of methods for modeling the effectiveness of projects to ensure the survivability of information systems. An analysis of existing research on the topic of the paper revealed a contradiction between the need for practice in the relevant modeling methods and the lack of appropriate theoretical and applied approaches. The purpose of the study is to develop methods for modeling the development of projects to ensure the survivability of information systems, in particular, taking into account the possibilities of additional financing of technologies for accelerating project implementation. The basic models of project and technology development were analyzed: models of exponential infinite growth, linear growth, and exponential entry into the saturation zone. A generalization of the basic models in a single logistic dependence was proposed. The logistic dependence was determined to be the most universal and adequate for modeling the processes of project and technology development. A classification of logistic development dependencies was performed: EGEL/BiS, EL/BiS, EL/BLO, EL/BiF, and their main properties were analyzed. For each type of dependency, a model was built for different parameter values corresponding to different scales of projects to ensure the survivability of information systems. An approach was proposed to implement the “Time is Money” principle, namely, a procedure was proposed for converting additional funding into acceleration of project implementation deadlines. For this purpose, a time multiplier value was proposed, which is a function of the amount of additional funding, has a logistic nature, and determines the patterns of the project implementation acceleration indicator depending on the amount of additional funding. Simulation was performed for a progressive time multiplier, which leads to acceleration of project implementation, and simulation was performed for a regressive time multiplier, which leads to inhibition of project implementation. It was found that the use of a time multiplier does not change the qualitative nature of project development dependencies.</p>
      </abstract>
      <kwd-group>
        <kwd>eol&gt;computer simulation model</kwd>
        <kwd>information system</kwd>
        <kwd>survivability</kwd>
        <kwd>logistic dependence</kwd>
        <kwd>useful effect</kwd>
        <kwd>resource</kwd>
        <kwd>management decision support</kwd>
        <kwd>automation</kwd>
        <kwd>optimization</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        It is not enough to simply create an information system. It is also necessary to ensure its stable
functioning in conditions of malicious and unintentional harmful influences. The issue of ensuring
the survivability of information systems has become especially relevant in conditions of war.
Relevant projects are aimed at ensuring the survivability of information systems, which have their
life cycle and the dependence of the useful effect on input resources. Financial, material, human
resources, intangible assets, and time resources can be considered as input resources [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. For
simplification, the required number of resources is usually planned for the project stages. It is then
assumed that each stage is provided at a sufficient level and further control of the project’s success
is carried out using the dependencies of the project’s useful effect on time. Verifying the
correctness of management decisions by implementing them in real projects carries the risk of
unexpected consequences and can lead to large economic losses. It is safer and more economically
feasible to use modeling. Models are used for a deeper study of the patterns of development of
specific types of projects and for predicting the possible consequences of various options for
alternative management decisions to find optimal project management. Of particular interest is the
search for ways to accelerate project implementation and predict the dynamics of development for
such situations.
      </p>
      <p>Thus, the development of methods for building models of project effectiveness to ensure the
survivability of information systems is a relevant task. Also relevant is the issue of modifying
existing development models to take into account the possibilities of accelerating project
implementation. For this purpose, in this work, time multipliers were introduced into the model,
which takes into account the impact of additional funding on the possibilities of accelerating
project implementation.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Analysis of existing studies</title>
      <p>
        Survivability is the ability to realize the goal of functioning under adverse influences [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ].
Survivability should be ensured by comprehensive actions to ensure certain properties of
information systems, properties of projects for the creation of such systems, a set of organizational
measures, appropriate process management, high-quality planning, and forecasting of possible
consequences of management decisions.
      </p>
      <p>
        A large number of applied methods for ensuring the survivability of information systems are
built based on numerical assessment and analysis of information security risks [
        <xref ref-type="bibr" rid="ref3 ref4 ref5 ref6">3–6</xref>
        ].
Unfortunately, these approaches do not use the potential of forecasting methods based on modeling
dynamic processes of project development.
      </p>
      <p>
        Forecasting the consequences of management decisions to counter cyberattacks of an
epidemiological nature was implemented in work [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] based on the use of dynamic models of
epidemic development. Unfortunately, the dynamics of the development of relevant projects to
counter threats to the survivability of information systems were not considered.
      </p>
      <p>
        Models for ensuring the survivability (guaranteeability) of information systems (in particular,
situational centers) of critical infrastructure facilities were considered in the works [
        <xref ref-type="bibr" rid="ref8 ref9">8, 9</xref>
        ]. The value
of recent works lies in the creation of models for the development of information systems.
Unfortunately, the issues of the dynamics of the development of survivability projects were not
considered. Also, insufficient attention was paid to the issues of taking into account financial
resources.
      </p>
      <p>
        The issues of optimizing the financing of projects for the creation of information protection
systems are considered in [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. However, the issues of financing technologies for accelerating
project implementation are not considered.
      </p>
      <p>
        Methodological approaches at the level of generalization of best-world practices are considered
in [
        <xref ref-type="bibr" rid="ref11 ref12">11, 12</xref>
        ]. Unfortunately, these works do not use the tools of dynamic models that would allow
predicting the consequences of management decisions and finding optimal solutions for managing
projects to ensure the survivability of information systems.
      </p>
      <p>When analyzing existing research, a contradiction was identified between the need for practice
in methods for modeling the effectiveness of projects to ensure the survivability of information
systems and the lack of appropriate theoretical and applied approaches.</p>
      <p>Purpose of the paper: development of methods for modeling the development of projects to
ensure the survivability of information systems, in particular, taking into account the possibilities
of accelerating project implementation through additional financing of project implementation
acceleration technologies.</p>
    </sec>
    <sec id="sec-3">
      <title>3. Classification of logistic models of effectiveness of projects ensuring the survivability of information systems</title>
      <p>Previously, the authors used an atomic development model, which can also be applied to the
analysis of the useful effect of projects to ensure the survivability of information systems (Fig. 1).
Such a model is sometimes called the “black box” model. This means that during the analysis it is
important to focus on the input resources, the output useful effects, and the functional dependence
f(x), which is hidden in the “black box”.
The most common “black box” models are exponential infinite growth models.
,
linear growth</p>
      <p>( a−d )
E=d +</p>
      <p>T
exponential entry into the saturation zone
❑
( t −s ) ,</p>
      <p>E=d +( a−d )( 1−e−T1 (t−s)) .</p>
      <p>Or you can use a logistic growth model, which combines all three of the above models (Fig. 2).</p>
      <p>1
0.8
tc0.6
e
f
f
E
,E0.4
It is easy to see that the lower part of the logistic model is similar to the exponential model of
infinite growth, the middle part is similar to the linear growth model, and the upper part is similar
to the exponential model in the saturation zone. The logistic dependence in integral form has the
form
(1)
(2)
(3)
(4)
Here d and a are the ordinates of the lower and upper asymptotes, respectively, s is the abscissa of
the point of central symmetry of the logistic dependence, T is the constant value of the logistic
dependence. In its meaning, the constant value of the logistic dependence is similar to the constant
value of the exponent but differs from the latter in scale by a factor of 2.</p>
      <p>The graph (Fig. 2) clearly shows the lower and upper asymptotes and two segments on these
asymptotes are marked, corresponding to the constant values of the logistic dependence T 1, which
together with the ordinates of the asymptotes determine the growth rate of the development
process of the project to ensure the survivability of the information system.</p>
      <p>The main assumption of the study is that we are investigating projects that, within the
framework of the selected technologies to ensure the survivability of information systems, have an
upper limit of development. That is, after a certain period, the development process approaches the
upper asymptote and cannot exceed it. To be precise, it cannot touch the asymptote, but can only
infinitely approach it. This corresponds to the real situation of project development. To rise above
the current asymptote, it is necessary to introduce new technologies that simply have a different
upper asymptote, which is located higher. However, this can lead to certain development delays at
the initial stages of project implementation.</p>
      <p>The figure (Fig. 3) shows the logistic dependences of the growth of the effect of projects that use
different information technologies, which provide different levels of the maximum useful effect
(upper asymptote). The distinctive features of these dependencies are that they contain both a
section similar to an exponential in the zone of infinite growth and a section similar to an
exponential in the zone of approaching the limit. We will classify such forms of logistic
dependences as EGEL (Exponential Growth + Exponent with a Limit).</p>
      <p>In terms of physical content, the ordinate of the dependence corresponds to the indicators of the
success of the project. This can be income, profit, the amount of damage that was avoided, the
quality of protection, the level of survivability, the percentage of guaranteed operability of the
information system, the speed of the system, etc.</p>
      <p>A feature of the technologies presented in (Fig. 3) is that they have a stage of almost zero
development at the beginning of implementation and, in addition, periods of rapid growth that
begin at noticeably different points in time. That is, these projects have fundamentally different
durations of the initial stages of implementation.</p>
      <p>5
4</p>
      <sec id="sec-3-1">
        <title>EGEL: Big is Slow</title>
        <p>T5
T3</p>
        <p>T4</p>
        <p>T2
T1
T1
20</p>
        <p>T2</p>
        <p>T3
It is logical that the higher the potential of the maximum level of useful effect of a technology, the
more time such a technology requires for implementation. We will denote the type of such projects
as BiS (Bigger is Slower). Although in some cases, even for projects with different values of the
upper limit of technology development (upper asymptote), the implementation time does not differ
significantly (Fig. 4), but it still corresponds to the BiS type.</p>
        <p>T1</p>
        <p>T2</p>
      </sec>
      <sec id="sec-3-2">
        <title>EGEL: Big is Slow</title>
        <p>T5
T3</p>
        <p>T4
E4
E3
E2
E1
E25
E15
The logistic dependencies discussed above are inherent in almost all technologies that start from
zero or almost from zero. They are characterized by the presence of a stage of almost zero growth
at the beginning of the technology implementation and all of them are EGEL/BiS projects.</p>
        <p>At the same time, some technologies practically do not lose time for implementation and
immediately begin to produce a useful effect that is proportional to the time spent (Fig. 6).
To diversify the computational experiment conditions, one study also considered projects that had
a large difference in the maximum level of development of the technology they used (Fig. 5).
EGEL: Big is SlowT25</p>
        <p>T15
T15</p>
        <p>T25
Over time, such technologies also reach the limits of their capabilities and slow down their
development. Visually, such dependencies are similar to the dependencies of exponential
development in the saturation zone. Therefore, we will further classify them as EL dependencies
(Exponential function with Limit). In addition to BiS projects, there are also BLO projects (Bigger
have Bigger Limit Only), which grow from the same trunk and differ only in the level of the upper
asymptote (Fig. 7).
It is also worth highlighting BiF projects (Bigger is Faster), in which large projects grow faster than
small ones. We consider such types of projects rather for the sake of completeness of the
classification. Because they are either very rare or completely unrealistic (Fig. 8).
E9
E5
Thus, the classification of projects that we analyzed includes the following types of projects:
EGEL/BiS, EL/BiS, EL/BLO, and EL/BiF.</p>
      </sec>
    </sec>
    <sec id="sec-4">
      <title>4. Modification of models taking into account the principle of “Time is</title>
    </sec>
    <sec id="sec-5">
      <title>Money”</title>
      <p>The dynamics of the growth of the useful effect of projects over time was considered under the
conditions of normal resource provision of projects. Any material resource at the input of the
project can be estimated in terms of money. Any resource is converted into an output useful effect
according to the logistic dependence on the entire life cycle of the project or at its stages.
Regarding the time resource, the issue is not so obvious. The study determined that it is difficult to
establish a direct time-money relationship. However, money can be used as an input resource in
technologies aimed at accelerating technological processes. Let us introduce the concept of a “time
multiplier,” as a multiplier that shows the degree of acceleration of technological processes with
the help of additional financing.</p>
      <p>We consider projects that have normal (normative or planned) resource provision. Therefore,
with zero funding for time acceleration technologies (time multipliers), the project will develop in
the usual way. With additional funding for time multiplier technologies, all basic project operations
will be performed faster. In practice, this can be achieved by introducing additional personnel who
will work in the second or third shift, by purchasing more powerful computing resources that
allow faster and more efficient solutions to the issue of ensuring the survivability of information
systems, or by purchasing more effective software, or by purchasing analytical information from
other companies regarding possible malicious actions by potential information security violators,
etc. At the same time, time multiplier technologies, like other technologies, have their upper limit
on the acceleration of basic project processes. On the other hand, time multiplier technologies do
not turn on instantly. There is a certain level of initial financing of these technologies, which gives
a zero increase in the value of the time multiplier. That is, the dependence of the time multiplier on
the input financing is also logistic. The only fundamental difference from the dependencies that we
considered above is that at the zero moment, the value of the multiplier is always equal to 1 (Figure
9). To ensure this condition, it is necessary to solve the following equation for the ordinate of the
lower asymptote</p>
      <p>After transformations we get
1=SL (t )=d +</p>
      <p>a−d</p>
      <p>.</p>
      <p>2 (t−s)
d =1+(1−a) e T</p>
      <p>.
1.8
1.6
1.4
E=SLE ( t SLt ( kt t )) .
Further interaction between the material resources of the time multiplier and time resources can be
described by the following dependence
(5)
(6)
(7)
Here M is the money entering the time multiplier technology, SLt ( kt t ) is the dependence of the
time multiplier value on the amount of money entering its input, kt is the specific value of
financing per unit of time, t is time, SLE is the logistic dependence of the useful effect of the
technology of ensuring the survivability of the information system depending on the time of
implementation of the corresponding project. In this case, the linear dependence of the time-based
financing increase of the time multiplier is considered.</p>
    </sec>
    <sec id="sec-6">
      <title>5. Progressive Time Multiplier</title>
      <p>The time multiplier that accelerates the implementation of the project (Figure 9) will be called
progressive. The results of modeling the impact of the progressive time multiplier technology on
the basic projects EGEL/BiS, EL/BiS, and EL/BLO, which we analyzed above, are presented in (Figs.
10–13). The modeling results show that the use of the progressive time multiplier accelerated the
implementation of projects. But at the same time, it did not change the qualitative picture of the
dependence of the useful effect on time for all types of projects.</p>
      <p>E5
E4
E3
E2
E1
E25
E15
tc15
e
f
f
E
,10
E</p>
      <p>EGEL:TB5ig is Slow
T3</p>
      <p>T4
T1</p>
      <p>T2
0</p>
      <p>T1 T2 T3 T4 T5
50</p>
      <p>100
t, time</p>
      <sec id="sec-6-1">
        <title>EGEL: Big is Slow</title>
        <p>T25
T15
T7
5
E4
E3
E2
E1
E9
E5
4 T4</p>
      </sec>
      <sec id="sec-6-2">
        <title>EL: Big is Slow</title>
        <p>T9 EL: Big have Bigger Lim Only</p>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>6. Regressive time multiplier</title>
      <p>In addition to the progressive time multiplier, there may also be a regressive time multiplier, which
slows down the project implementation (Fig. 14). The regressive time multiplier may appear as a
result of the action of unfavorable factors in the development of the project. Its introduction is
necessary for the systematic consideration of possible project development options. The regressive
time multiplier model is represented by a logistic dependence that decreases with time. The
multiplier begins its movement from the asymptote d, which we previously called the lower
asymptote, and decreases its value to the asymptote a, which we previously called the upper
asymptote. That is</p>
      <p>d &gt;a (8)</p>
      <p>In this case, it would be more correct to call d the ordinate of the asymptote of the beginning of
the movement, and the value of a the ordinate of the asymptote of the end of the movement. The
results of modeling the impact of the regressive time multiplier technology on the basic projects
EGEL/BiS, EL/BiS, and EL/BLO are presented in (Figs. 15–18).
0.8
1 T1
0</p>
      <p>0
8
6
t
c
e
f
f
4
E
,
E T3</p>
      <p>T5
E4
E3
E2
E1
E9
E5
The modeling results show that the use of the regressive time multiplier slows down the
implementation of projects. But at the same time, just as in the case of the progressive multiplier, it
does not change the qualitative picture of the dependence of the useful effect on time for all types
of projects.</p>
    </sec>
    <sec id="sec-8">
      <title>Conclusions</title>
      <p>The paper proposes a classification of project development patterns: EGEL/BiS, EL/BiS, EL/BLO,
EL/BiF. This classification can be applied to projects to ensure the survivability of information
systems. The models are modified taking into account the “Time is Money” principle. For this
purpose, the “time multiplier” indicator is proposed, which allows linking financial resources with
indicators of project implementation acceleration. The models are modified taking into account
time multipliers. The modeling results for the progressive time multiplier and for the regressive
time multiplier are obtained. The analysis of the modeling results showed that the use of time
multipliers changes the time frames of projects, but does not affect the qualitative picture of the
patterns of project development.
While preparing this work, the authors used the AI programs Grammarly Pro to correct text
grammar and Strike Plagiarism to search for possible plagiarism. After using this tool, the authors
reviewed and edited the content as needed and took full responsibility for the publication’s content.</p>
    </sec>
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