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    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Principles of Computing Resources Planning in Cloud-Based Problem Solving Environment</article-title>
      </title-group>
      <contrib-group>
        <aff id="aff0">
          <label>0</label>
          <institution>South Ural State University</institution>
          ,
          <addr-line>Chelyabinsk</addr-line>
          ,
          <country country="RU">Russia</country>
        </aff>
      </contrib-group>
      <fpage>22</fpage>
      <lpage>28</lpage>
      <abstract>
        <p>\Problem-solving environments" recently became a widely accepted approach to providing computational resources to solve complex eScience problems. This approach represents a problem as a workow, orchestrating a set of various computational services. The existing cloud computing resources planning methods do not take into account a relation between such services, problem domain speci cs, predicted workow execution timespan, etc. On the other hand, usage of cloud system provides e cient HPC resources usage, distributing tasks on the most suitable resources. Therefore, we need to develop algorithms that provide e cient cloud system resources usage and take into account domainspeci c information of the problem.</p>
      </abstract>
      <kwd-group>
        <kwd>cloud planning</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>problem-solving environment
work ow
cloud
Nowadays cloud systems become the primary provider to solve problems in
physics, biological, and social research. These problems are characterized by
structural complexity which causes di erent resources (informational, software
or hardware) to be integrated into a single solution. The problem often can be
represented as a work ow, orchestrating a set of actions represent computational
parts of the whole problem.</p>
      <p>Each action can require a di erent amount of computing resources and a
speci c execution environment to work. Comparing to \classical" approach to
HPC resources provision, cloud computing systems provide more e cient usage
of computational resources, providing each task a unique execution environment
and mapping them to the most suitable resources. Also, cloud system can provide
a user-friendly web interface for computational research tasks submission.</p>
      <p>
        To provide scientists and engineers a transparent access to the computing
resources a Problem Solving Environment (PSE) concept is commonly used. A
PSE is a software solution that warps and provides a problem-oriented access to
computational resources to solve a speci c class e-Science problems. PSE uses
the language of the target problem domain, and users do not need to have a
specialized knowledge of the underlying hardware or software to submit and get
a solution of their computational problem [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
      </p>
      <p>A PSE problem domain consists of a nite set of task classes. Each task
class is a set of tasks that have the same semantics and the same set of input
parameters and output data. This limits the class of problems that can be solved
using the PSE. On the other hand, this would allow using a domain-speci c
information of task for selecting a set of computing resources and planning the
task's execution in the cloud system.</p>
      <p>The aim of the paper is to describe the principles of computing resources
planning in Cloud-based Problem Solving Environment. It's required to solve
the following tasks for gain the aim of paper:
1. Analyze related solutions for the planning of execution of problem-solving
work ow's.
2. De ne a structure of cloud system for problem-solving environment's
deployment.
3. Describe a scheme of an approach for the computing resources planning in</p>
      <p>Cloud-based problem-solving environment.</p>
      <p>The paper is organized as follows. In section 2 we present the review of the
systems provide work ow's execution and methods used to support the resources
scheduling for work ow execution. In section 3 we describe the main
components of a cloud-based PSE. In section 4 we provide the scheme of an algorithm
for the planning of computing resources in the Cloud-based problem-solving
environment. In section 5 we summarize the results of our research and provide
further research directions.
2</p>
    </sec>
    <sec id="sec-2">
      <title>Scheduling Methods in Work ow Systems</title>
      <p>
        A lot of scienti c groups in e-Science and engineering elds use work ow
platforms to provide scienti c computations. Authors of the papers [3{5] describe
an analysis of modern (Scienti c Work ow Management Systems (SWMS) that
support e-Science approach, such as Pegasus [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ], Kepler [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], Taverna [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ], Galaxy
[
        <xref ref-type="bibr" rid="ref9">9</xref>
        ]. The Pegasus system [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] is widely used to solve problems in such elds as
astronomy, bioinformatics, climate simulation, etc. the System contains 4
components: Planner (Work ow Mapper), Work ow Manager, Task dispatcher (Job
Scheduler), Monitoring system (Monitoring Component). Work ow is presented
as DAX- le (XML-representation of directed acyclic graph). Pegasus uses
HTCondor [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] task scheduler. This scheduler provides computing resources
management in cluster computing systems, GRIDs [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ], and cloud computing systems
[
        <xref ref-type="bibr" rid="ref13">13</xref>
        ]. Authors of paper [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ] present the cloud-based Code Execution Framework.
The paper describes an architecture of the framework to run a problem-solving
environment in the cloud system, like Amazon EC2 cloud or OpenStack. These
systems can use numerous optimization algorithms to provide scheduling the
resources in the computing system, including Grid or cloud system. The
algorithms like Improved Di erential Evolutionary Algorithm combined with the
Taguchi method, Multi-Objective Evolutionary Algorithm based on NSGA-II,
Case Library and Pareto Solution based hybrid GA Particle Swarm
Optimization, Auction-Based Biobjective Scheduling Strategy [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ] have the main
drawback that they do not use information about previous executions.
      </p>
      <p>
        Problem-oriented scheduling (POS) algorithm, that takes into account both
speci cs of the problem-oriented jobs and multi-core structure of the computing
system nodes is proposed in [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ]. The algorithm allows one to schedule execution
of one task on several processor cores with regard to constraints on the scalability
of the task.
      </p>
      <p>
        The paper [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ] describes the scheduling algorithm PO-HEFT for a work
owbased problem-solving environment, which would e ectively use a
domainspeci c information (such as task execution time, scalability limits, and the
amount of data transfer) for prediction of cloud computing environment
resources load. The paper also presents a model for cloud problem-solving
environment. These algorithms are designed for scheduling the work ow actions'
execution - when the task has to run to provide a minimal makespan, for
example. The reviewed algorithms don't select the set of computing resources required
for task's execution and don't distribute the services on the computing nodes to
utilize the maximum of computing resources.
3
      </p>
    </sec>
    <sec id="sec-3">
      <title>Model of Cloud-Based Problem Solving Environment</title>
      <p>We can de ne the following main components of cloud-based problem-solving
environment:
1. Service is an entity that implements functionality for particular
computational action. Service provides transparent access to its functionality and
interacts with another system's components by an open protocol
(HTTPbased or binary). Service is implemented as a virtual machine le, including
a base image and applied software for particular computation action
implementation.
2. Base image - is a basic image of a computational environment (a Virtual
machine) that includes a set of system software tools (\middleware"). The
following elements are included in the common middleware set of the base
image:
{ execution agent (provides common interface for submission, execution,
live cycle management of tasks);
{ agent of monitoring system;
{ storage client.</p>
      <p>
        Virtual machine is an isolated computational environment that provides a
limited set of resources for service's execution. Virtual machines work on
computing nodes of a computing cluster. Every computing node of a cluster
runs an agent of virtualization platform that provides execution for virtual
machines and cloud system's agent for virtual machines management.
Several virtual machines can share resources of one computing node, such as
main memory, computing resources, a bandwidth of the network adapter,
local storage of the computing node. We can de ne a set of performance
characteristics for every virtual machine [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ].
3. Work ow executor is a cloud computing system service that provides
services orchestration, executing computational actions by work ow planners
request.
4. Work ow planner - generates a list of services with the computing resources
are required for service's execution and send the list to the Work ow
Executor.
5. Work ow predictor - predicts task's execution parameters for all tasks in the
job on the basis of the domain-speci c parameters.
6. Cloud monitoring system - monitors the execution of task and computing
resources' consumption. After a task is nished the Cloud monitoring system
sends the statistics about consumption of resources during task's execution
with the speci ed domain-speci c arguments of tasks for further
improvement in task's prediction.
4
      </p>
    </sec>
    <sec id="sec-4">
      <title>Work ow-Based Resources Planning in Cloud-Based PSE</title>
      <p>We can de ne four layers in the proposed work ow planning approach consists
(see Figure 1): the work ow layer, the service layer, the virtual machine layer and
the computing nodes layer. The input parameters for the work ow planning wold
be abstract problem-solving work ow, the set of the domain-speci c arguments'
values, paths for input and result les, and quality-of-service (QoS) description.
The following agreements can be de ned in QoS:
{ work ow execution time;
{ maximum amount of computing resources;
{ cost of calculation.
4.1</p>
      <sec id="sec-4-1">
        <title>Work ow Planning Layer</title>
        <p>
          The work ow layer implements the transformation of the abstract work ow into
the executable job. The data sources of the input parameters are being connected
with the certain tasks and sub- ows of the work ow during the transformation.
The abstract work ow [
          <xref ref-type="bibr" rid="ref3">3</xref>
          ] is executable if input arguments of any task are
independent of the result of another task's execution. In other words, the arguments
for work ow control nodes (such as decision and fork none) may come only before
work ow execution, the in uence of the intermediate arguments are prohibited.
4.2
        </p>
      </sec>
      <sec id="sec-4-2">
        <title>Service Planning Layer</title>
        <p>The Service layer provides assignment of particular services to the required
computing resources for any task in the work ow. The Service layer performs the
assignment on the basis of task executions prediction by Work ow predictor.
The Work ow predictor sends to the Work ow planner the following prediction
information:
{ time of the task execution (on the 1 computing core);
{ the amount of main memory, needed for the task execution;
{ maximum task scaling (how much cores can be provided to the task);
{ the amount of the result data;
{ prediction accuracy for each value.
4.3</p>
      </sec>
      <sec id="sec-4-3">
        <title>Virtual Machine Planning Layer</title>
        <p>The Virtual machine layer selects type (\instance") for each service from the
existing types in the cloud computing system. This layer performs the instances
selection, using the prediction of computing resources required for the certain
task execution, but (1) Work ow executor can allocate another set of resources
for QoS satisfaction, (2) if the prediction accuracy is low, i.e. most likely
prediction if false, then executor choose the type of virtual machine which is default
for the certain service.
4.4</p>
      </sec>
      <sec id="sec-4-4">
        <title>Computing Node Planning Layer</title>
        <p>
          The Computing node planning layer maps virtual machines' onto computing
nodes on the basis of a virtual machine computing resources and a volume of
node's local storage. At this layer, planner tends to place related virtual machine
from the work ow (which on this layer are presented as Task-to-VM list [
          <xref ref-type="bibr" rid="ref18">18</xref>
          ])
on the same node to reduce the amount of data are transferred between the
computing nodes.
5
        </p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>Conclusion</title>
      <p>In this paper, we provide a description of an approach for computing resources
planning for work ows execution in the Cloud-based problem-solving
environment. We present the components of the Cloud-based problem-solving
environment. The scheme of work ow planning approach consists of 4 layers: work ow
layer, service layer, virtual machines layer, computing nodes layer. Currently, we
implement the problem-solving algorithm for planning work ows in the
Cloudbased problem-solving environment. For the validation and evaluation of the
planning algorithm, it is planned to implement a model of problem-based Cloud
platform in the simulation environment, as well as on the basis of real HPC
system.</p>
      <p>Acknowledgements. The reported paper was supported by RFBR, research
project No. 15-29-07959.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          1.
          <string-name>
            <surname>Kobashi</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Kawata</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Manabe</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Matsumoto</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Usami</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Barada</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          :
          <article-title>PSE park: Framework for problem solving environments</article-title>
          .
          <source>J. Converg. Inf. Technol</source>
          .
          <volume>5</volume>
          ,
          <issue>225239</issue>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          2.
          <string-name>
            <surname>Fox</surname>
            ,
            <given-names>G.C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gannon</surname>
          </string-name>
          , D.:
          <article-title>Special issue: Work ow in grid systems</article-title>
          .
          <source>Concurr. Comput. Pract</source>
          . Exp.,
          <volume>18</volume>
          ,
          <fpage>1009</fpage>
          -
          <lpage>1019</lpage>
          (
          <year>2006</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          3.
          <string-name>
            <surname>Deelman</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gannon</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shields</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Taylor</surname>
          </string-name>
          , I.:
          <article-title>Work ows and e-Science: An overview of work ow system features and capabilities</article-title>
          .
          <source>Futur. Gener. Comput. Syst</source>
          .
          <volume>25</volume>
          ,
          <issue>528</issue>
          {
          <fpage>540</fpage>
          (
          <year>2009</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          4.
          <string-name>
            <surname>Taylor</surname>
          </string-name>
          , I.,
          <string-name>
            <surname>Deelman</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Gannon</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shields</surname>
            ,
            <given-names>M.S.:</given-names>
          </string-name>
          <article-title>Work ows for e-Science</article-title>
          .
          <source>Work. e-Science Sci. Work</source>
          . Grids.
          <volume>1</volume>
          {
          <issue>523</issue>
          (
          <year>2007</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          5.
          <string-name>
            <surname>Miles</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wong</surname>
            ,
            <given-names>S.C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fang</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Groth</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Zauner</surname>
            ,
            <given-names>K.P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Moreau</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          :
          <article-title>Provenancebased validation of e-science experiments</article-title>
          .
          <source>Web Semant</source>
          .
          <volume>5</volume>
          ,
          <issue>28</issue>
          {
          <fpage>38</fpage>
          (
          <year>2007</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          6.
          <string-name>
            <surname>Deelman</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vahi</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Juve</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rynge</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Callaghan</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Maechling</surname>
            ,
            <given-names>P.J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mayani</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Chen</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          , Ferreira Da Silva,
          <string-name>
            <given-names>R.</given-names>
            ,
            <surname>Livny</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            ,
            <surname>Wenger</surname>
          </string-name>
          ,
          <string-name>
            <surname>K.</surname>
          </string-name>
          :
          <article-title>Pegasus, a work ow management system for science automation</article-title>
          .
          <source>Futur. Gener. Comput. Syst</source>
          .
          <volume>46</volume>
          ,
          <issue>17</issue>
          {
          <fpage>35</fpage>
          (
          <year>2015</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          7.
          <string-name>
            <surname>Altintas</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Berkley</surname>
            ,
            <given-names>C.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jaeger</surname>
            ,
            <given-names>E.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jones</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ludascher</surname>
            ,
            <given-names>B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Mock</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          :
          <article-title>Kepler: an extensible system for design and execution of scienti c work ows</article-title>
          .
          <source>Sci. Stat</source>
          .
          <source>Database Manag</source>
          .
          <year>2004</year>
          .
          <source>Proceedings. 16th Int. Conf. I</source>
          ,
          <volume>423</volume>
          {
          <fpage>424</fpage>
          (
          <year>2004</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          8.
          <string-name>
            <surname>Oinn</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Addis</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Ferris</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Marvin</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Senger</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Greenwood</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Carver</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Glover</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Pocock</surname>
            ,
            <given-names>M.R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wipat</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Li</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Taverna: A tool for the composition and enactment of bioinformatics work ows</article-title>
          .
          <source>Bioinformatics</source>
          .
          <volume>20</volume>
          ,
          <issue>3045</issue>
          {
          <fpage>3054</fpage>
          (
          <year>2004</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          9.
          <string-name>
            <surname>Goecks</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Nekrutenko</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Taylor</surname>
          </string-name>
          , J.:
          <article-title>Galaxy: a comprehensive approach for supporting accessible, reproducible, and transparent computational research in the life sciences</article-title>
          .
          <source>Genome Biol</source>
          .
          <volume>11</volume>
          ,
          <issue>R86</issue>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          10.
          <string-name>
            <surname>Wolstencroft</surname>
            ,
            <given-names>K.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Haines</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Fellows</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Williams</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Withers</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Owen</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Soiland-Reyes</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Dunlop</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Nenadic</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          , Fisher,
          <string-name>
            <given-names>P.</given-names>
            ,
            <surname>Bhagat</surname>
          </string-name>
          ,
          <string-name>
            <given-names>J.</given-names>
            ,
            <surname>Belhajjame</surname>
          </string-name>
          ,
          <string-name>
            <given-names>K.</given-names>
            ,
            <surname>Bacall</surname>
          </string-name>
          ,
          <string-name>
            <given-names>F.</given-names>
            ,
            <surname>Hardisty</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            ,
            <surname>Nieva de la Hidalga</surname>
          </string-name>
          ,
          <string-name>
            <given-names>A.</given-names>
            ,
            <surname>Balcazar</surname>
          </string-name>
          <string-name>
            <surname>Vargas</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.P.</given-names>
            ,
            <surname>Su</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S.</given-names>
            ,
            <surname>Goble</surname>
          </string-name>
          ,
          <string-name>
            <surname>C.</surname>
          </string-name>
          :
          <article-title>The Taverna work ow suite: designing and executing work ows of Web Services on the desktop, web or in the cloud</article-title>
          .
          <source>Nucleic Acids Res</source>
          .
          <volume>41</volume>
          , (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          11.
          <string-name>
            <surname>Thain</surname>
            ,
            <given-names>D.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Tannenbaum</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Livny</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          :
          <article-title>Distributed computing in practice: The Condor experience</article-title>
          .
          <source>Concurrency Computation Practice and Experience</source>
          . vol.
          <volume>17</volume>
          , no.
          <volume>24</volume>
          ,
          <fpage>323</fpage>
          -
          <lpage>356</lpage>
          (
          <year>2005</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          12.
          <string-name>
            <surname>Deelman</surname>
          </string-name>
          , E.:
          <article-title>Grids and Clouds: Making Work ow Applications Work in Heterogeneous Distributed Environments</article-title>
          .
          <source>Int. J. High Perform. Comput. Appl</source>
          .
          <volume>24</volume>
          ,
          <fpage>284</fpage>
          -
          <lpage>298</lpage>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref13">
        <mixed-citation>
          13.
          <string-name>
            <surname>Juve</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Deelman</surname>
          </string-name>
          , E.:
          <article-title>Scienti c work ows and clouds</article-title>
          .
          <source>Crossroads</source>
          .
          <volume>16</volume>
          ,
          <fpage>14</fpage>
          -
          <lpage>18</lpage>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref14">
        <mixed-citation>
          14.
          <string-name>
            <surname>Ludescher</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Feilhauer</surname>
            ,
            <given-names>T.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Brezany</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          :
          <article-title>Cloud-Based Code Execution Framework for scienti c problem solving environments</article-title>
          .
          <source>J. Cloud Comput. Adv. Syst. Appl. 2</source>
          ,
          <issue>1</issue>
          {
          <fpage>16</fpage>
          (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref15">
        <mixed-citation>
          15.
          <string-name>
            <surname>Pandey</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Wu</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Guru</surname>
            ,
            <given-names>S.M.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Buyya</surname>
            ,
            <given-names>R.:</given-names>
          </string-name>
          <article-title>A particle swarm optimization-based heuristic for scheduling work ow applications in cloud computing environments</article-title>
          .
          <source>In: Proceedings - International Conference on Advanced Information Networking and Applications</source>
          , AINA. pp.
          <volume>400407</volume>
          (
          <year>2010</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref16">
        <mixed-citation>
          16.
          <string-name>
            <surname>Sokolinsky</surname>
            ,
            <given-names>L.B.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Shamakina</surname>
            ,
            <given-names>A. V.</given-names>
          </string-name>
          :
          <article-title>Methods of resource management in problemoriented computing environment</article-title>
          .
          <source>Program. Comput. Softw</source>
          .
          <volume>42</volume>
          ,
          <issue>17</issue>
          {
          <fpage>26</fpage>
          (
          <year>2016</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref17">
        <mixed-citation>
          17.
          <string-name>
            <surname>Nepovinnykh</surname>
            ,
            <given-names>E.A.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Radchenko</surname>
            ,
            <given-names>G.I.</given-names>
          </string-name>
          :
          <article-title>Problem-Oriented Scheduling of Cloud Applications : PO-</article-title>
          <source>HEFT Algorithm Case Study. 2016 39th Int. Conv. Inf. Commun. Technol. Electron. Microelectron. MIPRO 2016 - Proc</source>
          .
          <volume>196</volume>
          {
          <issue>201</issue>
          (
          <year>2016</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref18">
        <mixed-citation>
          18.
          <string-name>
            <surname>Yang</surname>
            ,
            <given-names>Z.W.L.N.Y.</given-names>
          </string-name>
          :
          <article-title>A market-oriented hierarchical scheduling strategy in cloud work ow systems</article-title>
          .
          <volume>63</volume>
          , (
          <year>2013</year>
          ).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>