=Paper= {{Paper |id=Vol-1260/paper5 |storemode=property |title=Positioning Traffic in NoSQL Database Systems by the Use of Particle Swarm Algorithm |pdfUrl=https://ceur-ws.org/Vol-1260/paper5.pdf |volume=Vol-1260 |dblpUrl=https://dblp.org/rec/conf/woa/Wozniak14 }} ==Positioning Traffic in NoSQL Database Systems by the Use of Particle Swarm Algorithm== https://ceur-ws.org/Vol-1260/paper5.pdf
    Positioning traffic in NoSQL database systems by
           the use of particle swarm algorithm

                                                             Marcin Woźniak
                                                        Institute of Mathematics
                                                   Silesian University of Technology
                                                 Kaszubska 23, 44-100 Gliwice, Poland
                                                   Email: Marcin.Wozniak@polsl.pl

    Abstract—In this paper, application of particle swarm al-           (using methods like [21] or [20]) server responses to the
gorithm in positioning and optimization of traffic in NoSQL             requests, but this goes according to the income queue. Earlier
database is discussed. Sample system is modeled with independent        requests must be served first and others according to arrival
2-order hyper exponential input stream of packets and exponen-          time. The problem is to position this system for most efficient
tial service time distribution. Optimization is solved using particle   operation (we shall define optimal service, vacation and in-
swarm algorithm for various scenarios of operation.
                                                                        come parameters). In this paper NoSQL database system will
                                                                        be positioned for most efficient service and lowest possible cost
                       I.   I NTRODUCTION                               of work by the use of particle swarm optimization algorithm
    In modern computer science, artificial intelligence (AI)            (PSO).
as well as evolutionary computing (EC) is one of most
important fields, widely applied in various tasks. There are                        II.   A PPLIED MASS SERVICE MODEL
many applications of AI in sciences and industry. The power
of such approaches lies within the dedicated mechanisms is                  For NoSQL database systems various methods of modeling
used to simulate sophisticated phenomenon. On the other                 and simulation can be applied. Mainly we try to analyze
hand some techniques of EC were proven very efficient for               the model, which describes operation. Operation model is
searching optimal solutions, easy to implement and precise.             defined for applied queueing system (QS). Service description
Let us give same examples. AI applied to create learning                of NoSQL database, where dedicated QS is applied to optimize
sets are discussed in [1], [2]. Some aspects of positioning             operation cost defines Tservice , Tincome and Tvacation , which
computing network models by the use of EC are presented                 describe average time of service, average income time and
in [3], [4] and [5]. Moreover, AI is used for the optimization          average vacation time (backup, conservation and etc.), respec-
of industry processes [6], [7], [8]. AI is also applied for             tively. All these are independent random variables, where the
systems which require dedicated solutions [9], [10], [11], as           symbols in time t are:
well as for agents oriented programming and object oriented                 •    τ1 — the first busy period starting at t = 0;
refactoring techniques [12], [13], [14], [15]. In NoSQL systems             •    δ1 — the first idle time (first vacation time and first
we use dedicated solutions to increase performance. These                        standby time);
applications are especially designed for given purposes, please             •    h(τ1 ) — the number of packets served during τ1 ;
see [16]. We must build applications to serve clients requests,             •    X(t) — the number of packets in the system at t.
search in database, maintain service and more. All these
aspects demand special mechanisms like dedicated sorting                In this paper is discussed simulation and positioning of NoSQL
and indexing algorithms and queueing systems to administrate            database traffic modeled with dedicated QS, where we define
incoming requests. Dedicated sorting algorithms help to or-             only one request arrival and response departure.
ganize large data sets as fast as possible. Some examples of
dedicated sorting algorithms are discussed in [17], [18], [19]          A. Analytical results
and [20]. While in [18] and [20] is presented dedicated version
of quick sort, where implemented modifications enabled faster              Modeling traffic in NoSQL systems is non-trivial problem.
sorting. In [17] is discussed dedicated merge sort, which even          Classical cost structure is considered in [25]. While in [26],
more efficient version is presented in [21]. Moreover extended          [27], [28] are presented most important aspects of positioning
research on these situations are discussed in [22] and [23],            and cost optimization. Various queueing models for applied
where research on efficient methods of indexing and sorting             type of the server are investigated in [29], [30], [31], [32],
large NoSQL systems are presented. Here will be discussed               [33], [34], [35]. Please see also [36] and [37] for a review of
another important aspect of optimal service in large NoSQL              important results on modeling and positioning.
systems - traffic simulation and positioning.
                                                                            In this paper are applied results of the research on similar
    Traffic in the network and therefore efficient service can          objects, see [38] and [39] for joint transform of first busy
increase Quality of Service (QoS) [24]. We can simulate                 period, first idle time and number of packets completely served
the network traffic, where NoSQL database server is serving             during first busy period in GI/G/1-type systems. More on
various clients. Clients send requests and server collects them         generally distributed service times and infinite buffers can be
to proceed actions. After processing knowledge in database              found in [40] and [41]. All these research results are helpful to
model and position QS of different type as discussed in [42]          then for model of traffic finally we have:
[43], [4] and [44]. Where in [42] or [43] was given an idea
to apply evolutionary computation (EC) in QS simulation and                                        ∂
                                                                                       En τ1 = −      Bn (s, 0, 1)     ,            (6)
positioning. An extension of the research for sophisticated QS                                     ∂s              s=0
were published in [4]. And finally main analytical model with         similarly we have:
detailed description and assessments for traffic in the system
was given in [44]. Let us see the model of QS for NoSQL                                            ∂
                                                                                       En δ1 = −      Bn (0, %, 1)     .            (7)
database traffic.                                                                                  ∂%              %=0

    To model NoSQL server operation was used a finite-
buffer H2 /M/1/N -type QS, similar to server traffic modeling              III.   A PPLIED PARTICLE S WARM O PTIMIZATION
                                                                                                ALGORITHM
functions discussed in [45] and [46]. Let it be here presented
only a brief description, just to help in understanding NoSQL             Particle swarm optimization algorithm (PSO) has been
positioning and simulation problem (for details please see            shown in [47]. In the initial form PSO was modeling behaviors
[44]). Incoming requests describes 2-order distribution func-         that can be observed in young birds or fish, which in the
tion:                                                                 cluster behave in a very specific way. Thanks to the ease of
                                                                      implementation and adaptation to different tasks PSO algo-
       F (t) = p1 1 − e−λ1 t + p2 1 − e−λ2 t , t > 0, (1)
                                              
                                                                      rithm has become one of the most commonly used algorithms
where λi > 0 for i = 1, 2 and p1 , p2 ≥ 0. Inter-arrival times        in it’s original or modified versions. In [48] is presented
are mixed of two exponential distributions with parameters            adaptivity of this methods to different initial conditions of
λ1 and λ2 , which are being “chosen” with probabilities p1            positioned object. While in [49], [50] and [51] many possible
and p2 . In the system, there are (N − 1) places in queue             aspects of application of various EC methods in engineering
and one for packet in the service. System starts working at           optimization are discussed. In [52] PSO application in relay
t = 0 with at least one packet present. After busy period the         times is presented. Finally discussion on theoretical aspects of
server begins vacation which is modeled with 2-order hyper            convergence and stability can be found in [53], [54] and [55].
exponential distribution function:                                    Let us discuss behavior of typical swarm.

      V (t) = q1 1 − e−α1 t + q2 1 − e−α2 t , t > 0. (2)
                                                                        In the swarm similar operations are performed by many
                                                                      individuals of the same species. In action, individuals com-
Interpretation of parameters αi , i = 1, 2 and q1 , q2 is similar     municate with each other in a manner characteristic for the
to that for λi , i = 1, 2 and p1 and p2 . If at the end of vacation   species. Communication helps to exchange information and as
there is no packet present in the system, the server is on            a result the whole swarm is moving in a certain direction or
standby and waits for first arrival to start service process. If      behaves like one big organism. PSO algorithm uses the insights
there is at least one packet waiting for service in the buffer        that emerge from the observation of swarms of fish or insects
at the end of vacation, the service process starts immediately        that are looking for food or a safe place. This process can
and new busy period begins.                                           be described in mathematical model. If we accept the goal of
                                                                      optimizing criterion function of the object, we can talk about
    Functions F (·) and V (·) help to simulate operation of           optimizing algorithm.
the examined NoSQL system, where inter-arrival times and
vacation are defined in (1) and (2). In the research PSO is used          PSO algorithm searches the space of test solutions by
to find optimal set of parameters λi , pi , µ and αi . To describe    matching trajectories of individuals (particles) in a quasi-
minimal amount of resources to perform all operations rn (c1 )        stochastic way. A particular individual is a vector and it’s
is defined:                                                           movement is the result of stochastic and deterministic com-
                                                                      ponents of movement model. Stochastic component corre-
                     Qn (c1 )   r(τ1 )En τ1 + r(δ1 )En δ1             sponds to random walk. In contrast, deterministic component
        rn (c1 ) =            =                           ,    (3)
                     En (c1 )         En τ1 + En δ1                   of the movement model is distance between particles, or
                                                                      other feature, which is modeled in mathematical equation. In
where the symbols are: r(τ1 )-fixed unit operation costs during
                                                                      subsequent periods individual particles move in looking for
busy period τ1 , r(δ1 )-fixed unit operation costs during idle
                                                                      the global optimum, where because of stochastic component
time δ1 , En τ1 -means of busy period τ1 and En δ1 -idle time δ1
                                                                      this movement also has a random character. This combination
on condition that system starts with n packets present. In (3)
                                                                      gives ability to efficiently search the test area of the simulated
are used means of busy period and vacation (idle) time. The
                                                                      or positioned object. If during motion the particle is on a
explicit formula with detailed information and description for
                                                                      new position, which is characterized by better properties of
conditional joint characteristic functions of τ1 , δ1 and h(τ1 ) is
                                                                      the optimum, for this position it updates the knowledge. In
presented in [4] and [44]. Here let us briefly discuss modeling
                                                                      further exploration particle accepts found value as the optimum
of applied QS. General equation to calculate this values is:
                                                                      and starts searching in relation to this value. In each iteration
 Bn (s, %, z) = E{e−sτ1 −%δ1 z h(τ1 ) | X(0) = n}, 2 ≤ n ≤ N,         of the algorithm, the particles can communicate with each
                                                             (4)      other and share information about the sought optimum. If we
where s ≥ 0, % ≥ 0 and |z| ≤ 1, n ≥ 1. Details on this                consider that all particles in the swarm want to reach the sought
equation are discussed in [17], [4] and [44], where using it we       optimum criterion function for the positioned object, in the end
can define, components of (3) total cos of work:                      we can take as the optimum best of all-values. In this way,
                                                                      entire swarm is communicating between it’s individuals while
       En e−sτ1 = E{e−sτ1 | X(0) = n} = Bn (s, 0, 1),          (5)    looking for the global optimum of the criterion function.
A. PSO model                                                                Algorithm 1 Basic PSO applied to position NoSQL database
                                                                            system traffic
    Actions taken while searching for the optimum criterion                  1: Define all coefficients: α–optimum value memory factor,
function of the object are written as mathematical equations.                   β–optimum position memory factor, generation– number
The model of particle swarm movement keeps the communica-                       of iterations in the algorithm, particles–number of parti-
tion between particles based on a deterministic factor, but also                cles in the swarm,
introduces randomness of the movements. To build the model                   2: Dedicated criterion function: lowest cost of NoSQL system
of the swarm behavior in the solution space of the object are                   operation (3),
used the following assumptions:                                              3: Create at random initial population,
                                                                             4: t:=0,
   •     Points in the search space are seen as potential solu-              5: while t ≤ generations do
         tions to moving particle swarm.                                     6:    Move particles according to (9) and (8),
                                                                             7:    Sort particles according to the value of criterion func-
   •     Each particle is seeking for optimum, which is deter-                     tion,
         mined by it’s position in the space.                                8:    Evaluate population and take best ratio of them to next
   •     At the end of PSO iteration, the particles interact with                  generation,
         other particles and change information.                             9:    Rest of particles take at random,
                                                                            10:    Next generation: t + +,
   •     As a result of communication global optimum is                     11: end while
         selected, relative to which all particles are continuing           12: Best particles from the last generation are potential
         their search.                                                          optimum.

   •     Number of moving particles is determined.
                                                                                                   IV.    R ESEARCH RESULTS
In the model, we mean a particle moving in a virtual way. We
only model the choice of the optimum to which particle has                      Research results help to predict possible response time and
moved. Selected points in the study area are compared, and                  optimize service cost rn (c1 ) considered in different variants:
among them is chosen the global optimum, see also [56] for                  under-load, critical load and overload. PSO simulations were
details on convergence and stability of PSO.                                performed for r(τ1 ) = 0.5 and r(δ1 ) = 0.5. It means
                                                                            that modeled NoSQL database system uses 0.5 energy unit
    PSO algorithm for each particle takes the form of xti whose             each vacation and work period. For other system types these
i components correspond to dimensions of the test space. Each               values may be changed in (3), what makes presented model
particle is moving at the speed vit appropriate for the swarm               flexible and easily applicable. All presented research results
in a particular PSO iteration. These values vary in subsequent              are averaged values of 100 PSO samplings for 20 particles
iterations of the algorithm. Speed of movement of the particles             in 80 iterations with α = 0.4 and β = 0.4. In each iteration
is described by the formula:                                                best ratio = 90%, what means that 72 best particles were
                                                                            moved to next generation and 8 were taken at random. This
   vit+1 = vit + α · 1 · [g∗t − f (xti )] + β · 2 · [xt∗ − xti ],   (8)   helped to search entire object space for optimum values, where:

where the symbols are: vit –speed of i particle in t iteration,                •    Average service time: Tservice = µ1 ,
α–optimum value memory factor, β–optimum position mem-                         •    Average time between packages income into the sys-
ory factor, 1 , 2 ∈ [0, 1]–random values, g∗t –optimum for t                      tem: Tincome = λp11 + λp22 ,
iteration, xt∗ –optimum position for t iteration, f (xti )– fitness
function value for i particle in t iteration, xti –position of i               •    Average vacation time: Tvacation = αq11 + αq22 ,
particle in t iteration.
                                                                               •    Examined system size: N = buffer size +1.
    Equation repositioning particle swarm movement in each                  Scenario 1.
iteration of the PSO algorithm is defined using formula:                    PSO was performed to find set of parameters for lowest cost
                                                                            of work. In Table I are optimum values for all parameters that
                     xt+1
                      i   = xti + (−1)K · vit ,                       (9)   affect NoSQL server work. PSO positioned NoSQL system
where the symbols are: xti –position of i particle in t iteration,          TABLE I.          O PTIMAL PARAMETERS µ, λi , αi , pi , qi FOR i = 1, 2 AND
vit –speed of i particle in t iteration, K–random factor to change                                     LOWEST VALUE OF (3).

motion direction. The initial coordinates of the particle swarm                         λ1       λ2      α1    α2         p1      p2       q1   q2
position and their speed we take at random. However, it is                              2.9      2.3    1.43   0.32      1.78     1.3     6.1   3.5
possible also to apply some boundary criteria that will allow                            µ       0.6                  rn (c1 )   0.34
additional control of the swarm.                                                                  Tservice      Tincome          Tvacation
                                                                                       [sec]         1.67         1.18               15.20
    These two equations allow to change position of each
particle and therefore search entire space for the optimum of               to operate at minimum costs, if the service and vacation are
the modeled object. Let us now see possible implementation                  results from Table I. PSO was also arranged to position the
of PSO, which is presented in Algorithm 1.                                  system in various scenarios.
Scenario 2.                                                                         average on-line shop or customer service). Calculated values
NoSQL Tservice = 2[sec], what means that request service                            of Tservice and Tincome gave positioning for lowest cost of
takes about 2[sec]. Research results are shown in Table II.                         work. If the system works with calculated parameters QoS
                                                                                    is still very high, but also cost of service is possibly lowest,
TABLE II.           O PTIMAL PARAMETERS µ, λi , αi , pi , qi FOR i = 1, 2 AND       what means better profit for the owner. In the article, have
                             LOWEST VALUE OF (3).
                                                                                    been examined newly proposed methods for QS simulation
        λ1            λ2      α1       α2          p1       p2       q1      q2     and positioning (see also [4] and [44]). EC methods like PSO
       2.13          3.15    0.94      0.78      79.70     0.89    2.30     12.10   are excellent for simulation or positioning of different objects.
        µ            0.5                       rn (c1 )    0.37
                                                                                    PSO method helps to simulate complicated objects and because
                      Tservice          Tincome            Tvacation
       [sec]             2.08             37.70                17.96
                                                                                    of the free design, calculations are easy to perform. The experi-
                                                                                    ments confirmed PSO efficiency in simulation and positioning
                                                                                    the system in various scenarios representing common traffic
                                                                                    situations.
Scenario 3.
NoSQL Tservice = 0.5[sec]. This situation represents NoSQL
business service with heavy traffic and very efficient server                                                      R EFERENCES
machine. Research results with system positioning are shown
                                                                                     [1]   G. Capizzi, C. Napoli, and L. Paternò, “An innovative hybrid neuro-
in Table III.                                                                              wavelet method for reconstruction of missing data in astronomical
TABLE III.           O PTIMAL PARAMETERS µ, λi , αi , pi , qi FOR i = 1, 2 AND             photometric surveys,” in Artificial Intelligence and Soft Computing.
                             LOWEST VALUE OF (3).                                          Springer Berlin Heidelberg, 2012, pp. 21–29.
                                                                                     [2]   C. Napoli, F. Bonanno, and G. Capizzi, “An hybrid neuro-wavelet
         λ1            λ2      α1       α2         p1       p2       q1       q2           approach for long-term prediction of solar wind,” IAU Symposium, no.
        44.3          22.1    112.9     1.4       1.91       1     57.60     14.3          274, pp. 247–249, 2010.
         µ            2.00                     rn (c1 )    0.29
                                                                                     [3]   C. Napoli, G. Pappalardo, E. Tramontana, Z. Marszałek, D. Połap,
                        Tservice         Tincome            Tvacation                      and M. Woźniak, “Simplified firefly algorithm for 2d image key-points
       [sec]               0.5             0.09                10.72
                                                                                           search,” in IEEE Symposium Series on Computational Intelligence.
                                                                                           IEEE, 2014.
Using PSO it is also possible to position the system for                             [4]   M. Woźniak, W. M. Kempa, M. Gabryel, R. K. Nowicki, and Z. Shao,
Tincome . This will correspond to peculiar incoming traffic.                               “On applying evolutionary computation methods to optimization of
                                                                                           vacation cycle costs in finite-buffer queue,” Lecture Notes in Artificial
Scenario 4.                                                                                Intelligence - ICAISC’2014, vol. 8467 (PART I), pp. 480–491, 2014.
NoSQL Tincome was given as 2[sec], what means that requests                          [5]   C. Napoli, F. Bonanno, and G. Capizzi, “Exploiting solar wind time
are incoming to the server once in every 2 seconds. Research                               series correlation with magnetospheric response by using an hybrid
results are shown in Table IV.                                                             neuro-wavelet approach,” Proceedings of the International Astronomical
                                                                                           Union, vol. 6, no. S274, pp. 156–158, 2010.
TABLE IV.            O PTIMAL PARAMETERS µ, λi , αi , pi , qi FOR i = 1, 2 AND
                                                                                     [6]   G. Capizzi, F. Bonanno, and C. Napoli, “Hybrid neural networks
                             LOWEST VALUE OF (3).
                                                                                           architectures for soc and voltage prediction of new generation batter-
                                                                                           ies storage,” in Clean Electrical Power (ICCEP), 2011 International
              λ1         λ2      α1     α2      p1         p2       q1     q2
              3.7        4.5     1.3    1.4     6.2       2.5     13.1     7.2
                                                                                           Conference on. IEEE, 2011, pp. 341–344.
               µ         0.4               rn (c1 )       0.43                       [7]   F. Bonanno, G. Capizzi, A. Gagliano, and C. Napoli, “Optimal man-
                         Tservice       Tincome           Tvacation                        agement of various renewable energy sources by a new forecasting
             [sec]           2.5           2.23               15.22                        method,” in Power Electronics, Electrical Drives, Automation and
                                                                                           Motion (SPEEDAM), 2012 International Symposium on. IEEE, 2012,
                                                                                           pp. 934–940.
Scenario 5.                                                                          [8]   F. Bonanno, G. Capizzi, G. L. Sciuto, C. Napoli, G. Pappalardo, and
NoSQL Tincome was given as 0.5[sec], what means that                                       E. Tramontana, “A cascade neural network architecture investigating
requests are incoming to the server twice in every second.                                 surface plasmon polaritons propagation for thin metals in openmp,”
This situation is describing an extensively used database,                                 Lecture Notes in Artificial Intelligence - ICAISC’2014, vol. 8468, PART
                                                                                           I, pp. 22–33, 2014.
like these of business purpose. Research results are shown in
                                                                                     [9]   G. Capizzi, F. Bonanno, and C. Napoli, “Recurrent neural network-
Table V.                                                                                   based control strategy for battery energy storage in generation systems
TABLE V.            O PTIMAL PARAMETERS µ, λi , αi , pi , qi FOR i = 1, 2 AND              with intermittent renewable energy sources,” in Clean Electrical Power
                             LOWEST VALUE OF (3).
                                                                                           (ICCEP), 2011 International Conference on. IEEE, 2011, pp. 336–340.
                                                                                    [10]   F. Bonanno, G. Capizzi, and C. Napoli, “Some remarks on the appli-
              λ1         λ2      α1      α2        p1       p2      q1     q2              cation of rnn and prnn for the charge-discharge simulation of advanced
             27.1       27.2     0.8     0.4      16.1     1.1     5.6     4.3             lithium-ions battery energy storage,” in Power Electronics, Electrical
              µ         0.7                    rn (c1 )    0.33                            Drives, Automation and Motion (SPEEDAM), 2012 International Sym-
                         Tservice        Tincome           Tvacation                       posium on. IEEE, 2012, pp. 941–945.
             [sec]          1.43           0.63               17.75
                                                                                    [11]   G. Capizzi, F. Bonanno, and C. Napoli, “A new approach for lead-acid
                                                                                           batteries modeling by local cosine,” in Power Electronics Electrical
                                                                                           Drives Automation and Motion (SPEEDAM), 2010 International Sym-
                                                                                           posium on. IEEE, 2010, pp. 1074–1079.
                               V.      C ONCLUSIONS                                 [12]   C. Napoli, G. Pappalardo, and E. Tramontana, “Using modularity
                                                                                           metrics to assist move method refactoring of large systems,” in Sev-
    Positioned model was simulated in situations with prede-                               enth International Conference on Complex, Intelligent, and Software
fined time of service or time of income. Given times reflect                               Intensive Systems - CISIS 2013, July 2013, pp. 529–534.
situations when traffic is heavy and system must serve many                         [13]   R. Giunta, G. Pappalardo, and E. Tramontana, “AODP: refactoring code
requests (like business machines) or common traffic (like                                  to provide advanced aspect-oriented modularization of design patterns,”
       in Proceedings of Symposium on Applied Computing (SAC).           ACM,      [33]   E. Tramontana, “Automatically characterising components with con-
       2012.                                                                              cerns and reducing tangling,” in Proceedings of QUORS workshop at
[14]   E. Tramontana, “Detecting extra relationships for design patterns roles,”          Compsac. IEEE, 2013.
       in Proceedings of AsianPlop, March 2014.                                    [34]   Z. Niu and Y. Takahashi, “A finite-capacity queue with exhaus-
[15]   G. Pappalardo and E. Tramontana, “Suggesting extract class refactoring             tive vacation/close-down/setup times and markovian arrival processes,”
       opportunities by measuring strength of method interactions,” in Pro-               Queueing Systems, vol. 1, no. 31, pp. 1–23, 1999.
       ceedings of Asia Pacific Software Engineering Conference (APSEC).           [35]   Z. Niu, T. Shu, and Y. Takahashi, “A vacation queue with setup and
       IEEE, December 2013.                                                               close-down times and batch markovian arrival processes,” Performance
                                                                                          Evaluation Journal, vol. 3, no. 54, pp. 225–248, 2003.
[16]   Z. Marszałek and M. Woźniak, “On possible organizing nosql database
       systems,” International Journal of Information Science and Intelligent      [36]   H. Takagi, Queueing Analysis, vol. 1: Vacation and Priority Systems,
       System, vol. 2, no. 2, pp. 51–59, 2013.                                            vol. 2. Finite Systems. Amsterdam: North-Holland, 1993.
[17]   M. Woźniak, Z. Marszałek, M. Gabryel, and R. K. Nowicki, “Modified         [37]   N. Tian and Z. G. Zhang, Vacation queueing models. Theory and
       merge sort algorithm for large scale data sets,” Lecture Notes in                  applications. Berlin, Heidelberg: Springer - Verlag, 2006.
       Artificial Intelligence - ICAISC’2013, vol. 7895 (PART II), pp. 612–        [38]   W. M. Kempa, “Gi/g/1/ batch arrival queuing system with a single
       622, 2013.                                                                         exponential vacation,” Mathematical Methods of Operations Research,
[18]   ——, “On quick sort algorithm performance for large data sets,” in                  vol. 1, no. 69, pp. 81–97, 2009.
       Looking into the Future of Creativity and Decision Support Systems,         [39]   ——, “Characteristics of vacation cycle in the batch arrival queuing
       A. M. J. Skulimowski, Ed. Cracow, Poland: Progress & Business                      system with single vacations and exhaustive service,” International
       Publishers, 2013, pp. 647–656.                                                     Journal of Applied Mathematics, vol. 4, no. 23, pp. 747–758, 2010.
[19]   ——, “Triple heap sort algorithm for large data sets,” in Looking            [40]   ——, “Some new results for departure process in the m/g/1 queuing
       into the Future of Creativity and Decision Support Systems, A. M. J.               system with a single vacation and exhaustive service,” Stochastic
       Skulimowski, Ed. Cracow, Poland: Progress & Business Publishers,                   Analysis and Applications, vol. 1, no. 28, pp. 26–43, 2009.
       2013, pp. 657–665.                                                          [41]   ——, “On departure process in the batch arrival queue with single
[20]   ——, “Preprocessing large data sets by the use of quick sort algorithm,”            vacation and setup time,” Annales UMCS Informatica, vol. 1, no. 10,
       Advances in Intelligent Systems and Computing - KICSS’2013, vol.                   pp. 93–102, 2010.
       accepted–in press, 2014.                                                    [42]   M. Gabryel, R. K. Nowicki, M. Woźniak, and W. M. Kempa, “Genetic
[21]   Z. Marszałek, D. Połap, and M. Woźniak, “On preprocessing large                   cost optimization of the gi/m/1/n finite-buffer queue with a single
       data sets by the use of triple merge sort algorithm,” in Proceedings of            vacation policy,” Lecture Notes in Artificial Intelligence - ICAISC’2013,
       International Conference on Advances in Information Processing and                 vol. 7895 (PART II), pp. 12–23, 2013.
       Communication Technologies - IPCT’2014. Santa Barbara, California,          [43]   M. Woźniak, “On applying cuckoo search algorithm to positioning
       USA: The IRED, Seek Digital Library, 2014, pp. 65–72.                              gi/m/1/n finite-buffer queue with a single vacation policy,” in Pro-
[22]   M. Woźniak and Z. Marszałek, Selected Algorithms for Sorting Large                ceedings of the 12th Mexican International Conference on Artificial
       Data Sets. Gliwice, Poland: Silesian University of Technology Press,               Intelligence - MICAI’2013. IEEE, 2013, pp. 59–64.
       2013.                                                                       [44]   M. Woźniak, W. M. Kempa, M. Gabryel, and R. K. Nowicki, “A
[23]   ——, Extended Algorithms for Sorting Large Data Sets.            Gliwice,           finite-buffer queue with single vacation policy - analytical study with
       Poland: Silesian University of Technology Press, 2014.                             evolutionary positioning,” International Journal of Applied Mathematics
                                                                                          and Computer Science, vol. 24, no. 4, pp. accepted–in press, 2014.
[24]   C. Napoli, G. Pappalardo, and E. Tramontana, “A hybrid neurowavelet
       predictor for qos control and stability,” in Proceedings of AI*IA, ser.     [45]   D. Hongwei, Z. Dongfeng, and Z. Yifan, “Performance analysis of
       LNCS, vol. 8249. Springer, 2013, pp. 527–538.                                      wireless sensor networks of serial transmission mode with vacation on
                                                                                          fire prevention,” ICCET’10 IEEE CPS, pp. 153–155, 2010.
[25]   J. Teghem, “Control of the service process in a queueing system,”
       European Journal of Operations Research, vol. 1, no. 23, pp. 141–158,       [46]   V. Mancuso and S. Alouf, “Analysis of power saving with continuous
       1986.                                                                              connectivity,” Computer Networks, vol. 56, no. 10, pp. 2481–2493,
                                                                                          2012.
[26]   O. Kella, “Optimal control of the vacation scheme in an m/g/1 queue,”
                                                                                   [47]   J. Kennedy and R. C. Eberhard, “Particie swarm optimization,” in IEEE
       Operations Research Journal, vol. 4, no. 38, pp. 724–728, 1990.
                                                                                          International Conference on Neural Networks. Piscataway, NJ: IEEE,
[27]   R. Lillo, “Optimal operating policy for an m/g/1 exhaustive server-                1995, pp. 1942–1948.
       vacation model,” Methodology and Computing in Applied Probability,
                                                                                   [48]   M. Hu, T. Wu, and J. Weir, “An adaptive particle swarm optimization
       vol. 2, no. 2, pp. 153–167, 2000.
                                                                                          with multiple adaptive methods,” IEEE Transactions on Evolutionary
[28]   F. Bonanno, G. Capizzi, G. L. Sciuto, C. Napoli, G. Pappalardo, and                Computation, vol. 17, no. 5, pp. 705–720, 2013.
       E. Tramontana, “A novel cloud-distributed toolbox for optimal energy        [49]   S. Koziel and X. Yang, Computational Optimization, Methods and
       dispatch management from renewables in igss by using wrnn predictors               Algorithms. Berlin, Heidelberg: Springer, 2011.
       and gpu parallel solutions,” in Power Electronics, Electrical Drives,
       Automation and Motion (SPEEDAM), 2014 International Symposium               [50]   M. Gabryel, M. Woźniak, and R. K. Nowicki, “Creating learning sets
       on. IEEE, 2014, pp. 1077–1084.                                                     for control systems using an evolutionary method,” Lecture Notes in
                                                                                          Computer Science - ICAISC’2012, vol. 7269, pp. 206–213, 2012.
[29]   U. C. Gupta, A. D. Banik, and S. Pathak, “Complete analysis of
       map/g/1/n queue with single (multiple) vacation(s) under limited service    [51]   X. Yang, Engineering Optimisation: An Introduction with Metaheuristic
       discipline,” Journal of Applied Mathematics and Stochastic Analysis,               Applications. USA: John Wiley & Sons, 2010.
       no. 3, pp. 353–373, 2005.                                                   [52]   J. Bansal and K. Deep, “Optimisation of directional overcurrent relay
                                                                                          times by particle swarm optimisation,” in SIS’2008 Proceedings. IEEE,
[30]   U. C. Gupta and K. Sikdar, “Computing queue length distributions in
                                                                                          2008, pp. 1–7.
       map/g/1/n queue under single and multiple vacation,” Applied Mathe-
       matics and Computation, vol. 2, no. 174, pp. 1498–1525, 2006.               [53]   E. Baonabeau, M. Dorigo, and G. Theraulaz, Swarm Intelligence: From
                                                                                          Natural to Artificial Systems. Oxford University Press, 1999.
[31]   C. Napoli, G. Papplardo, and E. Tramontana, “Improving files availabil-
       ity for bittorrent using a diffusion model,” in IEEE 23nd International     [54]   V. Gazi and K. Passino, Swarm stability and optimization. Berlin,
       Workshop on Enabling Technologies: Infrastructure for Collaborative                Heidelberg: Springer, 2011.
       Enterprises - WETICE 2014, June 2014, pp. 191–196.                          [55]   X. Yang, Z. Cui, R. Xiao, A. Gandomi, and M. Karamanoglu, Swarm
[32]   F. Banno, D. Marletta, G. Pappalardo, and E. Tramontana, “Tack-                    Intelligence and Bio-inspired Computation: Theory and Applications.
       ling consistency issues for runtime updating distributed systems,” in              OXFORD, United Kingdom: Elsevier, 2013.
       Proceedings of International Symposium on Parallel & Distributed            [56]   M. Clerc and J. Kennedy, “The particle swarmexplosion, stability and
       Processing, Workshops and Phd Forum (IPDPSW). IEEE, 2010, pp.                      convergence in a multidimensional complex space,” IEEE Transactions
       1–8.                                                                               on Evolutionary Computation, vol. 6, no. 1, pp. 58–73, 2002.