# A Virtual Learning Architecture Enhanced by Fog Computing and Big Data Streams
## 2 Distance Learning
### State of the Art
#### 2.1.4 IT Staff  
As is the case with any IT-based system, distance learning environments must undergo a proper development, implementation and continuous improvement as well, usually performed by dedicated IT staff. As analyzed deeply in [9], the main design characteristics of a satisfactory VLE can be classified according to either the granularity of the provided features (coarse, medium or fine) or the origin of the features themselves. In this second case, the IT staff is in charge of those system features depending on the technical design of the environment such as trustworthiness, communication abilities, presence of feedback or of interactivity elements, media synchronicity, flexibility, screen design, accessibility and adaptability. In this regard, in [21], a novel design approach of VLEs is described. The proposed solution tries to smoothly apply aspect-oriented software development and multiagent programming to traditional object-oriented LMSs, by mapping objects to agents as useful joining points. In particular, the author separates the functionalities and concerns of a complex team-learning environment into different agents, each one in charge of different tasks, such as infrastructure interfaces, learning styles, learning tools, learning functions, queries, and so on. Even if the task was complex, the author partly succeeded in improving adaptability and re-usability, proven to be more and more important in VLEs in turn. Some other solutions, mainly based on the cloud computing paradigm [5], stress the reduction in installation efforts and maintenance times (through virtualization), as well as the necessary flexibility to set up complex lab scenarios and to reuse pre-configured frameworks. The cloud allows also for scalability in managing services with variable demands; however, it can also be sensitive to reliability problems, such as the possibility of outage episodes, which may affect IT staff especially in certain periods, such as enrollment, exams and the like. Moreover, in the cloud, different integration layers should be considered, e.g., the management of infrastructures, software, resources, services, as well as applications [22]. Particular attention should be employed, by IT technicians, to those levels, providing the coupling between the aforementioned technologies and a unified user interface. Despite these challenges, cloud solutions for VLEs are still very popular. For example, in [18], the authors propose a proprietary cloud-based virtual lab for mechatronics, enriched with a virtual meeting system, including communications with experts, a booking system for the physical equipment and a monitoring channel based on webcams. The proposed solution sheds light on the importance of carefully adapting, on the part of a dedicated IT staff, the different layers of the cloud to the specific laboratory, with particular care to micro-controllers, local servers, pieces of middleware, appropriate operating systems and devices (Arduino, Raspberry Pie, etc.). In [20], another system for virtual laboratories is presented. This solution takes advantage of remote access to virtual machines (Virtual Remote Labs) and needs IT staff to isolate virtual machines during certain time frames, when they have to be connected to actual physical devices or with network equipment. Technicians are also necessary to manage the four main layers (management, cloud, platform and data centers) of the proposal and to set hypervisors, such as VMware ([[http://www.vmware.com](http://www.vmware.com)]([http://www.vmware.com](http://www.vmware.com))), and virtual infrastructure managers, such as Open Nebula ([[http://opennebula.org/](http://opennebula.org/)]([http://opennebula.org/](http://opennebula.org/))). Moreover, some issues still to be solved concern the careful management of network communications and the need for a unique user interface and single sign on, as well as energy saving. In [12], other forms of virtual labs are exploited thanks to the mobile devices of students.