# Centralized vs. Decentralized Cloud Computing in Healthcare
## 3 Cloud Computing
### Cloud Computing Deployment Models  
Cloud infrastructure implementations fall into four distinct categories: private cloud, public cloud, hybrid cloud, and community cloud [27; 32]. The private cloud is exclusively controlled and centrally managed by a single entity, sometimes termed 'corporate cloud', as it operates under proprietary ownership. While external service providers can maintain private cloud servers, most enterprises opt for on-premise hardware, allowing internal teams to directly oversee and administer the infrastructure within their own data facilities [33]. Public cloud models are widely recognized as a standard cloud offering. They are publicly accessible platforms and are frequently employed for web-based applications, collaborative file distribution, and the storage of non-sensitive information. For collaborative endeavors and software creation, open-access cloud infrastructures are often advised. These systems rely on extensive hardware resources, owned and maintained by service vendors in large-scale computing facilities. In the realm of software engineering and quality assurance, openly accessible cloud platforms play a crucial role. Engineering teams frequently leverage these virtual ecosystems for their affordability, rapid deployment, and ease of configuration, making them ideal for developmental stages and test scenarios [34]. Integrating public and private cloud systems, hybrid infrastructures facilitate seamless interoperability between platforms. This fusion enables efficient data management and application performance across diverse environments. Enterprises with specific industry- or scale-related requirements often find this integrated approach ideal, as it caters to their need for both public and private cloud elements. Typically evolving from private infrastructures, hybrid cloud systems incorporate one or more public cloud services. This architecture proves advantageous for organizations facing data sensitivity concerns or regulatory constraints that demand specific protection, storage, and handling protocols [35]. Catering to groups with aligned interests or shared objectives, community cloud platforms offer specialized services to a network of affiliated users or entities. Participants in these ecosystems typically operate under common governance structures, adhere to similar security protocols, and follow unified policy frameworks. These collaborative digital environments can be deployed through various configurations: housed within a participating organization's facilities, maintained at a peer entity's location, managed by a single service provider, or distributed across a combination of these arrangements [36]. The structure of cloud computing ecosystems incorporates multiple essential elements: a front-end platform, back-end servers, network service, and a cloud-based delivery service. Figure 1 illustrates cloud architecture components. User interaction with cloud computing platforms occurs through front-end-client-side interfaces, serving as the entry point for accessing and utilizing cloud-based applications and services. Back-end infrastructure elements, including virtualized environments, processing units, data repositories, and security frameworks, form the core of cloud service operations. This back-end ecosystem,overseen by service providers, supplies the necessary resources for distributed computing functionalities [37]. The front-end encompasses web browsers, like Chrome, Firefox, and Opera; clients; and mobile devices. User interaction with cloud-based services occurs through visual digital interfaces, forming the foundation of client-side infrastructure. Network connectivity serves as the conduit linking user interfaces with core infrastructure, facilitating data exchange and operational synergy between these two domains [38]. Cloud-based software and platforms, accessible on demand, comprise the suite of services sought by end-users. Based on user requirements, the service orchestration layer determines and regulates access to specific cloud offerings.