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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