# Ontologies in Cloud Computing--Review and Future Directions
## 2 Background and Related Work
### Related Surveys of Ontology Usage in Conventional Computing  
Ontology is defined as the explicit formal specification of conceptualization [18]. Ontologies are absolutely the pillar of several cloud applications requiring specific domain knowledge [19]. In a cloud environment, identifying and categorizing cloud services in the real world could be challenging because cloud services are provided at various service levels with process data, business logic, and hardware capabilities [20]. Ontology offers organized rules of ideas, each with clearly stipulated guidelines that the machine can understand, thus contributing to machine intelligence [21]. The cloud ontology provides meta-information about data semantics, covering cloud models and their relationships [22]. An ontology represents domain knowledge; the ontology engineer creates ontology classes by making graphical models. This is because models are said to have clear semantics. Based on the above, ontology-based domain knowledge can create unambiguous formal rules such that models can be expressive and interpreted by both machines and humans [23]. Ontology has been applied to many areas since the advent of cloud computing, acting as the missing link between humans and machines to reconcile the heterogeneous nature of the cloud resulting from the lack of standard and governance structure. Ontologies are indispensable tools for semantic web-based application(s) [24]; hence, their evaluations are paramount for enhancing their (semantic) quality. Most ontology engineers would rather have a modular ontology rather than a general ontology. This is because a good quality modular ontology will promote reusability [25]. The research work carried out by [26] developed an architecture that uses dual core ontology components, namely, the Catalogue and Business Process Ontology, with the capacity for extension through the addition of specific domain ontologies. The catalog ontology explores Universal Business Languages (UBL), whereas the Business Process Ontology uses various applicable business metrics. The business process incorporates rules that different semantic analyzers for commercial practices can understand. The performance of an ontology is said to be efficient based on the depth selected; if the depth is very high, then it impliesthat the knowledge transfer will be very detailed. Otherwise, knowledge transfer and test will be superficial. Then, there will be no strategic advantage and the system will be lost [27]. The authors of the General Data Protection Regulation (GDPR) framework developed an architecture based on the results of the DAPRECO project. A product of GDPR contains not only legal instructions and ideas obtained within the legal environment, but semantic provisions based on obligations, permissions, and prohibitions [28]. The MEASUUR's ontology was developed as a model that offers a non-dynamic version of the enterprise configurations. This framework is being applied to various scenarios, and it has responded well by providing proof of strength. The authors proposed a system that supported an ontological judgment system to assist stakeholders in accepting such resolutions under electronic governance policies [29]. The authors of [30] proposed a process ontology-based approach to eliminate semantic ambiguity by providing a means to capture rich semantic information residing in business processes, which can be achieved by using domain-specific ontologies. The authors of [31] presented a framework consisting of a list of norms and a generic compliance checking approach based on process execution. The authors of [32] proposed a semantic framework based on an Internet of Things in Business Processes Ontology (IoT-BPO) semantic model. The authors of [33] created an ontology with the ability to depict relationships among various stakeholders involved in the cloud environment. The approach performs security assessment from different customers' points of view.