Cloud computing, cloud-based enterprise systems and virtualisation

Cloud computing is a kind of Internet – based computing that relies on sharing computing resources instead of local servers. It enables ubiquitous, on demand access to a pool of configurable computing resources. Cloud computing is similar to grid computing, which corresponds to a network of computers as well, but it is based on sharing unused processing cycles of these computers. Mainly cloud computing serves three tasks: “application”, “storage” and “connectivity”. Each task serves a different purpose and provides different contribution to businesses and individuals around the world [1] [2] [3]. 

One of the benefits of using cloud computing by companies is the potential to reduce IT operational costs by outsourcing hardware and software maintenance to the cloud providers. The latter allows companies to outsource many of their IT related task to the service (cloud) provider including upfront infrastructure and IT equipment maintenance costs and focus on projects that differentiate their businesses instead of on IT infrastructure [4]. 

Cloud computing utilizes large server networks that run low-cost consumer PC technology with specialized connectivity capabilities, however the core technologies behind cloud computing are: (i) the hardware virtualization which allows the end user to exclusively use a set of virtual resources and (ii) the service oriented architecture model which makes it easier for software components on computers connected over a network to cooperate. The standards for connecting the computer systems and the software needed to make cloud computing work, are not strictly defined, which provides the flexibility to the companies to define their own cloud computing technologies. 

Cloud computing promises several attractive benefits for businesses and end users such as [5]: 
Services on demand: Service catalogue and specific SLAs 
 Acceleration of services: end users can accelerate their processing tasks by using cloud's computing resources on demand. 
 Adaptability: companies can scale up as computing needs increase and scale down as demands decrease. 
 Security, Risk management, compliance: Standardization and automation of these procedures 
 Incident management and fails management: Monitoring and filtering of events by the service providers 
Business Model: users pay only for the resources and workloads they use. 

Cloud computing has become a popular approach in corporate data centers as it enables them to operate like the Internet through the process of enabling computing resources to be accessed and shared as virtual resources in a secure and scalable manner. Small and medium size business (SMEs), benefit from cloud computing as well, as there are able to save time and money by investing in cloud computing for certain applications. The adoption of cloud computing can help SMEs in growing revenue, reducing long-term IT cost, attracting new customers, improving cash flow, maintaining profitability, and, increasingly importantly, reacting to ever-changing market conditions. Using cloud computing, SMEs can access remote resources and expand or shrink services as business needs change [6]. Cloud computing provisions can be categorized in two ways based on two criteria: deployment models and service models. 

Deployment models 
Based on the NIST categorization (National Institute of Standards and Technology), cloud computing can be divided into four types [7]: 
 Private Cloud: In this case the cloud infrastructure is operated solely for an organization, even if it may be managed by the organization or a third part and may exist on premise or off-premise. Private cloud gives an organization the benefits of cloud computing without the restrictions of bandwidth, security exposures and legal issues that could be entailed by using external resources. However, this model is very costly and usually it is much time consuming for a company to establish a usable cloud. 
 Community Cloud: In this case the cloud infrastructure is shared by several organizations and supports a specific community that has similar concerns (e.g. mission, security requirements, and policy and compliance considerations). While the burden of building the cloud is lifted from the shoulders of each community member, this must be done by the community as a whole. 
 Public Cloud: In this case the cloud infrastructure is available to the general public or a large industry group and is owned by an organization selling cloud services. The main benefit of this model is easy and inexpensive to set-up, because the work needed for the cloud establishment is done by the cloud services provider. 
 Hybrid Cloud: This is a combination of two or more of the above mentioned types of clouds that remain unique entities but are bound together by standardized or proprietary technology that enables data and application portability. 

Service models 
Based on the aforementioned report published by NIST [8] the service models applied in cloud computing are the following: Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). 
 Software as a Service (SaaS): The service offers the consumer the capability to use the provider’s applications which run on the cloud. A thin client interface such as a web browser (e.g., web-based email) allows the accessibility to applications from various client devices. 
 Platform as a Service (PaaS): The service offers the consumer the capability to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure. 
 Infrastructure as a Service (IaaS): The service offers the consumer the capability to process storage, networks, and other fundamental computing resources where the consumer is able to deploy and run software, including operating systems and applications. The consumer in this case too does not manage or control the cloud infrastructure. 

Moreover, the following services models are suggested [9]: 
 Business Process as a Service (BPaaS) The service offers the consumer the capability to manage an entire business process as a service in the cloud. Generally, the underlying capabilities of a BPaaS platform (i.e., software, technology, infrastructure resources, etc.) are owned and managed by the Cloud Service Provider. Examples of business processes could be: payroll, CRM, billing, HR, order taking, information delivery etc. The main difference of this model with the SaaS model is that the former includes services partly performed by people and not just by the applications software as in the case of SaaS. 
 Information/Data as a Service (DaaS) The service offers the consumer the capability to set information/data and associated metadata using one or more established standards. This type of service is especially useful for large and complex data. 

Commercial Applications 
As mentioned above cloud computing is used mainly for three purposes: optimizing applications performance, storing large volume of data and connectivity purposes. Many companies choose to build their own clouds in order to maintain security, secure legal issues that are entailed by using external resources, and keep control of the infrastructure and the resources that will be used for their purposes. However, there are many examples of organizations that prefer to use a public cloud in order to avoid the cost and time consuming of the establishment of the cloud. These organizations address to external cloud services providers. Popular examples of public cloud providers are: 
 Infrastructure as a Service: in this case providers supply a virtual server instance and storage as well as APIs that let users (organizations) migrate workloads to a virtual machine. 
 Amazon Web Services 
 Microsoft Azure 
 Google Compute Engine 
 Platform as a Service: in this case providers host development tools on their infrastructures. Users access those tools over the Internet using APIs, Web portals or gateway software. 
 Amazon Elastic Beanstalk 
 Google App Engine 
 Software as a Service: in this case providers deliver software applications over the Internet 
 Microsoft Office 365 

Cloud computing in transportation 
Cloud computing is used by early adopters in the transportation industry. The data shows that the market growing fast. In 2008, total transit ridership reached an estimated 10.5 billion unlinked trips. The main solution the companies ask from in the sector of transport lies in bringing various measurements together into one useful dashboard. The connection directly to the cloud of transport services can bring multiple pieces of data together which become available, in near real-time, allowing managers to make quick adjustments for better service [10]. 

The Device Cloud 
Many vendors provide online hosting or software-as-a-service (SaaS) models to transportation organizations. SaaS essentially allows the customer to rent the software and access it online for a monthly fee. While these tools can benefit the business side of the transportation industry, the real value comes when the cloud intersects directly with fleet management devices. Bypassing SaaS and simply passing data directly from the device to the cloud saves time and also money. 

It typically takes long, to plan, procure and deploy IT infrastructure to connect embedded transportation devices to the network and capture valuable data. Transportation agencies use GPS devices, passenger counters, fare collectors and other devices to capture key data. Traditionally, these devices are plugged into a hard-wired Internet connection, and the data is downloaded onto a local PC connected to a network. The data is downloaded at specified intervals, such as each night or once per week. Many times the data are either never used, or analyzed once per month or even once per year to make service changes. 

The device cloud is a term coined by Eurotech, to describe how organizations can bring data from device to business application with an integrated solution to turn bits of data into valuable and actionable information. By storing device data in the cloud, both public and private transportation agencies can access data in near real-time. The device cloud is also scalable, secure and many times more cost-effective than traditional infrastructure for transportation IT departments. As cloud computing becomes more mainstream, transportation agencies are evaluating whether a cloud solution can be an efficient alternative to traditional computing networks. 

Simplifying the Dashboard using more useful data 
Using cloud computing for storing transportation data could beneficiary for travel/transport providers and agencies. Currently, the last ones collect various measurements ranging from travel time to fare collection. Then, the management of this data is done by different departments in these organizations. When all of these measures are stored in the cloud, transportation executives can access the data anytime and anywhere through a secure online portal. The creation of specific dashboards that extract the data needed, in considered to be invaluable in analyzing data. With a cloud computing infrastructure, the cloud service can pull information from all of the different databases and sources of information together into one simple and secure dashboard. At any given moment, the person in charge can generate a report containing both data such as fare collection and passenger counting with a single click. The elimination of operational times spent on processing data from different sources gained from cloud computing can minimize the personnel ‘s recurring time used to generate the same reports month after month, year after year. 

Making Quick Decisions with Faster Data through the Cloud 
In addition to minimizing personnel’s effort in regards to data manipulation with a simple dashboard, cloud computing can also provide the benefit of more immediate, near real-time data. Since data is sent to the cloud almost continuously, organizations can see realistic snapshots at any given moment. 

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[7] P. Mell and T. Grance, The NIST Definition of Cloud Computing, National Institute of Standards and Technology, Information Technology Laboratory, Technical Report Version 15, 2009. 
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