
 
computation.  Given  the  diversity  of  cloud  service 
offerings, it is an essential challenge for organizations 
to discover suitable cloud providers who can satisfy 
their requirements. There may be trade-offs between 
different  user  requirements  fulfilled  by  different 
cloud service providers. As a result, it is not sufficient 
to discover multiple cloud services. It is important to 
determine the most suitable cloud service through an 
evaluation for a specific situation (Garg et al., 2013; 
Whaiduzzaman  et  al.,  2014;  Wibowo  and  Deng, 
2016).  The  evaluation  of  available  cloud  services 
concerning  a  set  of  specific  criteria  is  complex 
(Bryman and Bell, 2015) due to the presence of the 
multi-dimensional  nature  of  the  evaluation  process 
and the presence of vagueness of the decision-making 
process (Arpaci et al, 2015). 
Kritikos  and  Plexousakis  relate  the  basic  web 
service  discovery  and  cope  with  the  topic  of 
requirements  for  web  services  discovery  (Kritikos 
and Plexousakis, 2009). The core of this process is 
matchmaking, which enlists the relevant services in 
the registry. Afterward, the selection is based on the 
ranking approach. First, various services are filtered 
and selected as per the user's preference who selects 
the options they want to use. This service can be very 
likely using Categorization of Super Matches, exact 
matches, partially Matches and service that fails. In 
this approach, the quality criteria are defined through 
literature,  based  on  OWL  Q,  and  consist  of 
availability,  reliability,  safety,  and  security  are 
considered as criteria. However, according to Hema 
Priya  and  Chandramathi,  (Hema  Priya  and 
Chandramathi,  2014),  these  criteria  cannot  be 
considered  all  together,  which  reduces  the 
opportunities for restrictions. They use numeric QoS 
parameters along with their measurement units and 
methods in OWL-Q. The criteria reflect users’ needs 
and  are  not  considered,  and  the  approach  is  only 
tested prototypically. 
A Delphi study conducted by Lang (Lang et al., 
2016)  defines  the  most  critical  criteria  for  cloud 
provider  selection.  Through  conducting  workshops 
and  panels  with  industry  experts  from  the  cloud 
computing  area,  the  authors  provided  a  list  of 
important  selection  criteria.  This  set  of  criteria 
consists of several attributes: certification, contract, 
deployment  model,  flexibility,  functionality, 
geolocation of service, integration, legal compliance, 
monitoring,  support,  a  test  of  the  solution,  and 
transparency of activities. Using all these criteria can 
provide  a  comprehensive  limitation  for  a  cloud 
service  selection.  Nevertheless,  they  do  not  offer 
measures for their criteria nor a matchmaking method 
to  prove  the  approach.  This  diminishes  the 
applicability  for  users  as  criteria  support,  tests  of 
solution and transparency of activities are not easy to 
measure,  and  thus  high  expertise  in  each  area  is 
necessary.  
A Description Logic-based method proposed by 
Dastjerdi supports the QoS-aware discovery of IaaS 
web-services  and  the  automatic  deployment  of 
appliances  on  selected  services  through  a  service 
(Dastjerdi  et  al.,  2011).  The  proposed  service 
matchmaking process has two parts – ontologies and 
a  matchmaking  algorithm.  The  goal  of  service 
matching  and  five  matching  operations  are  first 
specified,  such  as  the  concepts  of  exact  matching, 
plugin matching, non-matching, etc.  
In  most  cases,  the  project  context  provides  the 
language  used  in  the  service  description.  If  the 
language of the service description is an ontology, the 
matchmaker  service  is  based  on  ontology 
fundamentals.  In  other  cases,  the  service 
matchmakers  use  different  mathematical  methods. 
However,  service  matchmakers also  differ  in other 
factors:  the  target  service  requester,  the  supported 
service  layer,  their  definition  for  the  service 
matchmaking process, the types of requirements, and 
according to the quality and model used. 
Table  I  examines  20  different  service  selection 
projects. Seven of the selected projects focus on the 
selection of web-services, whereas the other projects 
focus  on  Infrastructure  or  Software  Layers.  As 
functional  requirements  are  underlying  on  the 
systems input/output, most research work is based on 
non-functional  aspects.  Thus,  the  matchmaking 
methods focuses on the matching of non-functional 
requirements, mainly QoS aspects. 
In the existing approaches, the service description 
and  quality  models  stem  mostly  from  the  web 
services  context.  Some  QoS  properties  that  are 
specific  to  cloud  services  are  not  considered,  for 
example,  scalability,  elasticity  and  different  price 
models. Moreover, some matching approaches do not 
provide concrete examples for the service properties 
targeted  by  their  service  matcher.  Considering  a 
quality  model,  the  approaches  are  beside 
(Repschlaeger  et  al.,  2012;  Wang  et  al.,  2014) 
linguistic  terms  most  often  SMI  and  OWL-Q. 
Whereas  OWL-Q  appears  mostly  for  web-service 
matching, SMI and CFR are used for the selection of 
cloud services. As three roles are involved in service 
selection,  the  cloud  service  customer  (CSC),  the 
cloud  service  provider  (CSP)  and  the  Selector  (S) 
getting an  in-depth look  into the research  projects, 
Table 2 shows that 20 projects are focusing on the 
same roles. Somu (Somu et al., 2017) include the CSP 
role, beside the CSC as an essential part for building
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