## 2 Literature Review
### Cloud Computing Services and Deployment Models  
According to [47], CC comprises a tripartite of services, infrastructure as a service (IaaS), platform as a service (PaaS) and software as a service (SaaS). The latter enables users to access applications via a cloud-based infrastructure. SaaS means that the infrastructure such as the servers, operating systems, and networks are essentially removed from the consumer, who no longer need to be concerned with this or with other issues such as data storage. To access the services, the customer uses either a direct interface, which is used for web-based emails such as Gmail, or a program interface such as Dropbox. Meanwhile, the IaaS model means that consumers can deploy and run the software, which they choose, through the provision of computing resources such as networks, storage, and processing. This can be achieved through varies softwares, which might be an application or even an entire operating system such as Microsoft Azure and Amazon Web Services, which are two examples of providers within this sphere. Finally, PaaS provides a platform for users to deploy applications on a broader cloud infrastructure and allows them to create and modify their applications by using libraries, services, and languages that have already been developed by a cloud platform provider such as Google App Engine or Heroku.  
A description of the four deployment models in cloud technology applications is seen in [47], where these cloud types are named as private, community, public, and hybrid. The private cloud, as the name suggests, is used solely within one organization and its infrastructure may be either self-managed or operated by a third party [51]. This model is usually chosen when security issues are a concern for a particular organization, so in the academic sector, this may be due to ownership of certain resources or to cultivate an online community [51].  
Concerning the community model, many institutions may use the same basic infrastructure that is hosted either by a third party or by one of the organizations that is part of the community. Organizations may consider this model to be an advantage either through shared costs and resources or because perceived risks are lessened when the model is shared [52]. This model may work well when used by cooperating organizations, or when institutions have a close relationship or are interlinked in some way but can be an issue in higher education sector where many similar institutions are essentially in competition with each other for students, funding and other resources.  
The public cloud is probably the most popular form of cloud deployment and is managed by the provider of the service, and the most well-known providers are Microsoft One Drive, Dropbox, and Google Drive as well as those provided by Amazon. In the field of education, users such as students, lecturers and faculty staff will probably be familiar with the system, which is one of its advantages.  
The final model of deployment is the hybrid cloud, which combines two or more models. Utilizing more than one model harnesses the benefits of each model and aims to mitigate the disadvantages of every single model as well as to provide a more flexible and wide-ranging approach.