CLOUD E-LEARNING

Abstract

The paper presents the main characteristics of a cloud-based e-learning system, by comparing it to other e-learning architectures like service-oriented architecture, event driven architecture, distributed computer. The first part of the paper shows these architectures and the way they fit to e-learning systems. The second part describes the main technologies that are used for developing such systems, while the third part is dedicated to e-learning databases. Finally, the last section takes an overview of the specialized e-learning functionalities that cloud computing brings. In this paper we clarify why cloud computing isn't a simple user-client architecture, why the security reaches a high level in cloud computing and why it is so important to keep all the users' needs in a pool of resource data. An important part of the paper is where we deal with cloud computing weaknesses and how they affect the e-learning process. The main problems are the internet access, students and professors' data that is kept on suppliers' servers. Overall one should be able to distinguish an authentic cloud computing e-learning system by its functionalities, availability, portability and, of course, interface. E-learning systems use all the advantages of a cloud computing architecture: the infrastructure, the platform and the services, and the paper details all these components that lead to a cloud e-learning architecture. The characteristics of a e-learning system in cloud may differ depending on the type of cloud architecture: public, private or hybrid. Moreover, from this point the philosophy and the implementation of the system take different turns. [PUBLICATION ABSTRACT]

Headnote

Abstract: The paper presents the main characteristics of a cloud-based e-learning system, by comparing it to other e-learning architectures like service-oriented architecture, event driven architecture, distributed computer. The first part of the paper shows these architectures and the way they fit to e-learning systems. The second part describes the main technologies that are used for developing such systems, while the third part is dedicated to e-learning databases. Finally, the last section takes an overview of the specialized e-learning functionalities that cloud computing brings.

In this paper we clarify why cloud computing isn't a simple user-client architecture, why the security reaches a high level in cloud computing and why it is so important to keep all the users' needs in a pool of resource data. An important part of the paper is where we deal with cloud computing weaknesses and how they affect the e-learning process. The main problems are the internet access, students and professors' data that is kept on suppliers' servers. Overall one should be able to distinguish an authentic cloud computing e-learning system by its functionalities, availability, portability and, of course, interface.

E-learning systems use all the advantages of a cloud computing architecture: the infrastructure, the platform and the services, and the paper details all these components that lead to a cloud e-learning architecture. The characteristics of a e-learning system in cloud may differ depending on the type of cloud architecture: public, private or hybrid. Moreover, from this point the philosophy and the implementation of the system take different turns.

Keywords: Cloud Computing, E-learning, database

I. E-LEARNING ARCHITECTURES

The mainly architectures that are used for developing an e-learning system are cloud computing, service-oriented architecture, distributed computing or event driven architecture. The ideal architecture would combine all of these architectures' advantages and integrate them in cloud environment. A service oriented learning platform can encapsulate each course and each exam as a web service that can be accessed world wide if the security protocols are passed. For extra protection, each service can have its own encrypted password that the student gets to have if he passes the previous exam.

Distributed e-learning also offers advantages in terms of security if data regarding courses, exams, students and teachers is stored on separate servers and the querying is made ad-hoc on each machine.

Most of the e-learning processes are interactive and this fact makes it mandatory that the elearning platform is driven by events like taking an exam, accessing a course, giving grades, viewing statistics etc.

Cloud computing can offer services driven by events and store data as a pool of resources, but it's not a simple user-client architecture. In a basic client-server architecture the processes are run on the clients machines, while the servers are supposed to store data In cloud computing the data is stored in datacenters and the distributed physically or virtualizes by distributed servers. The clients access the applications only via Internet. All the users' needs are expressed in events that are served as services. The services collect data from the pool of resources that are most of the time randomly distributed on datacenters. With data storage not being a problem, because of the huge available storing space on multiple servers, it is important to accumulate as much data as services can bring. Depending on the user's location or values of request's parameters, the service can access data on some server or others and remember how quick the answer was.

According to [1], in cloud computing the security reaches a high level due to data security, data privacy and data availability. Data security focuses on encryption, server security, client security and password security, while data availability uses techniques as geographic redundancy, SaaS (Software as Service) provider backups, user backups and data escrow. Data privacy covers the following areas: privacy polices, owners of data, data usage.

The main problems for cloud computing are the internet access and the fact that students and professors' data that is kept on suppliers' servers. If an exam is supposed to take place at a certain time and the Internet is not working students may be disqualified due to this abnormality. The best solution is to have deadlines and time periods for exams, but it should be the student's choice when to start the tests, depending on his availability and the network's capabilities. Also the server suppliers must be chosen considering their experience of storing data, security and confidentiality policies, hardware profile and location of servers (better to have servers in different locations).

II. MAIN TECHNOLOGIES THAT ARE USED FOR DEVELOPING ELEARNING SYSTEMS

E-learning systems can be developed on various platforms, using various software and technologies, but it should meet the learning technology standards in order to be part of a learning management system. The best choice for delivering learning products is by web services in cloud computing.

2.1 Learning technology standards

The standards for e-learning system relate mainly to metadata, package content, profile learner, student registration and communication content. They are described as follows:

* Metadata: cataloging the learning content and requires a consistent labeling that allows indexing, storage and retrieval of learning objects by various utilities (LOM).

* Package Content: standards and specifications contained packages allow transfer courses from one platform to another (IMS Content Packaging, IMS Simple Sequencing, ADL SCORM).

* Profile learner: personal data, learning plans, learning history, accessibility requirements, certifications and diplomas, awareness and participation in learning (Learner Information Profile - LIP).

* Student registration: registration information provided to allow components and content delivery management to identify and find their required elements (IMS Enterprise Specification, Schools Interoperability Framework).

* Communication content: it provides student data and information about previous activities (ADL SCORM).

2.2 Learning management system (LMS)

Learning management system defined by the SCORM can be divided into Learning Content Management System (LCMS) and Learning Management System (LMS). A learning content management system is a multi-user environment where developers can create content, store, reuse, manage and deliver digital learning content. LMS manages learning process and LCMS created and delivery of learning content. LCMS allows users to create and reuse small units of digital educational content. Use standard metadata of learning structures and standards for import and export formats allow learning objects (LO) to be created, shared and stored. To achieve interoperability between systems, LCMS is done using standard specifications for metadata content, package content and communication content. It swaps user profile and registration information provided by other systems, locates the LCMS courses and provides student activities.

2.3 Web services

Web services are feasible for interoperability of e-learning for the following reasons:

* Information is interchangeable between e-learning systems using XML files.

* Web services architecture is platform independent language and promoting interoperability and extensibility among different applications, platforms and frameworks existing in the market.

* Web services provide a unified programming model for developing and using intranet and Internet services.

When talking about web services, we must clarify the terms of service provider, service request and service discovery. Service Provider is the platform that hosts access to services and an execution environment for services or a service container, its role in the exchange of messages with the server.

Service Request seeks or initiates interaction with the service, while service discovery is a set of services where providers publish their service description, which can be centralized or distributed.

Educational information presented in XML format and considering the specifications SOAP (Simple Object Access Protocol) is exchanged between the service request and the service provider. Public service provider WDSL file containing information describing the message and finally allowing to generate a service request SOAP message and sending it to the correct destination.

Cloud computing as a platform is a new era of cloud computing offers the academic organization a familiar development experience, on-demand scalability, scale up when it needs capacity and pull it back when it doesn't, cost savings, and reduced time to market for the applications, all in a secure environment.

Currently, e-Learning systems are still weak on scalability at the infrastructure level. Several resources can be deployed and assigned just for specific tasks so that when receiving high workloads, the system need to add and configure new resources of the same type, making the cost and resource management very expensive.

Masud and Huang in [2] pointed out the consequences and implications regarding the development of e-Learning services within the Cloud Computing environment:

* Accessed via Web: it implies an ease of access since anywhere, any time and any one can access the application, greater demand for Web Development skills.

* No client-side software needed: therefore, it has reduced costs for subscriber, as no installation, software maintenance, deployment and server administration costs, and a lower total cost of ownership, reduced time-to-value, fewer IT staffis needed by the institution.

* Pay by subscription based on usage: which is suitable for Software Model Education market, and can gain access to more sophisticated applications.

* SaaS server may support many educational institutions: since the application is running on a server farm, the scalability in inherent to the system. As student usage grows, the software performance will not degrade.

* All subscriber data held on SaaS server: very high level of security is needed by SaaS provider in order to gain trust of subscribers and sophisticated software architecture. The subscriber data is distributed between many providers and it must be integrated in order to gain overview of business, higher demand for system and data integrators.

Several potential values of Cloud Computing for education as stressed by Ouf et al. in [3] include the following:

* No need for backing up everything to a thumb drive and transferring it from one device to another. It also means students can create a repository of information that stays with them and keeps growing as long as he wants them

* Crash recovery is nearly unneeded. If the client computer crashes, there are almost no data lost because everything is stored in the cloud.

* Allow students to work from multiple Places (home, work, library ), find their files and edit them through the cloud and browser-based applications can also be accessed through various devices (mobile, laptop and desktop computers, provided internet access is available) [4].

* Flexibility: Scale infrastructure to maximize investments. Cloud computing allows user to dynamically scale as demands change [5].

* Improved improbability: it is almost impossible for any interested person (thief) to determine where is located the machine that stores some wanted data (tests, exam questions, results) or to find out which is the physical component he needs to steal in order to get a digital asset.

* Virtualization: makes possible the rapid replacement of a compromised cloud located server without major costs or damages. It is very easy to create a clone of a virtual machine so the cloud downtime is expected to be reduced substantially.

* Centralized data storage: losing a cloud client is no longer a major incident while the main part of the applications and data is stored into the cloud so a new client can be connected very fast. Imagine what is happening today if a laptop that stores the examination questions is stolen.

* Monitoring of data access becomes easier in view of the fact that only one place should be supervised, not thousands of computers scattered over an extensive geographical area, for example. Also, the security changes can be easily tested and implemented since the cloud represents a unique entry point for all the clients [6].

III. E-LEARNING AND DATABASES

Like shown in [7], most Learning Management Systems (LMS) use to provide support to manage subjects, student groups, and facilities for content dissemination, learner's evaluation and communication between users. In this case, data are usually stored in a database using a relational model. In [7], in order to give semantics to entities and relations the authors describe the matching between classes and slots in the ontology proposed with the corresponding tables in the database. They propose a model for the database integration of these systems using ontology.

Web 2.0 technologies can be important. They allow individuals to create their own data, consume data from multiple sources and provide services to remix the data in a learning environment [8].

In [9] it is proposed the first open source on authoring system which introduces XML as the backend database system for storing question sheets made by educators and answers made by students.

3.1 Cloud storage

In a cloud solution using cloud storage can be a good idea. Cloud storage service is an emerging infrastructure that offers Platforms as a Service (PaaS). There are many solutions available. Amazon Simple Storage Service (Amazon S3) is regarded as the reference of cloud storage service. Amazon S3 provides virtually elastic and unlimited storage space. Users can access the internet-based storage service through using a set of simple interfaces and pay for the service of the amount of storage, Get Request, Put Request, data transfer in and data transfer out each month for one year. This offers full database functionality, accessed via common set of APIs.

As shown on its website and in [12], another solution, from Amazon: AWS has a form a cloud service catalog in which users can select preconfigured Amazon Machine Images (AMIs) to install on the Amazon cloud. Some of these AMIs are free; others aren't. Other cloud providers, such as MicrosoftAzure, have similar facilities, but Amazon is currently considered the best example. It offers a number of AMIs developed by Amazon developers. In this case, the cloud developers are part of the cloud provider organization. Amazon also offers AMIs developed by other organizations. An Oracle customer who wants to run an Oracle database on the Amazon cloud can use an AMI supplied by Oracle in the Amazon AMI catalog. The Oracle AMI contains a configured and installed Oracle environment and the customer will pay license fees to the supplier. The consumer who installs the Oracle AMI saves the time and trouble of downloading installing and configuring the database. In this case Oracle developers are acting as cloud developers.

In another case, the cloud developer may be the consumer who develops an AMI as an easily reproducible service. For example, in e-learning a library service can be build that can be then easily replicated for every instance.

DaaS (Data-as-a-Service) describes the ability to define data lists in a cloud service and then query against this data. Such a solution cannot be accessed by SQL-like interfaces.

In [10] the authors propose a general architecture of a cloud storage service system called CS3 with a simple, flexible and modular architecture with a hierarchical design reflecting common resource environments found in many academic settings. The system allows users to access their own data using SOAP and REST interfaces, offers a Web interface for users. Using a Web browser, users can upload, download, and look through their own data in CS3, which is similar to on-line disk you used. In [11] the scope of cloud storage systems is shown like in Figure 1. It assumes the presence of a storage gateway, which at its core contains a technical storage controller as the interface for all applications in need of storage.

3.2 Data security in the cloud

Data is subject to unavailability, corruption, loss and to undesired exposure. As security is concerned cloud solutions are probably not much more or less secure than installations on the consumer premises. Securing a cloud is not much different than securing an enterprise computing system. They are subject to the same kinds of threats and have the same solutions. The viruses attacking a cloud datacenter are the same viruses that attack an individual PC. However, the cloud provider takes care of most of the security responsibilities.

Cloud providers have begun getting certification in ISO/IEC 27001. This means that cloud consumers should familiarize themselves with ISO/IEC 27001. As shown in [12], understanding what it means to comply with ISO/IEC 27001 is likely to become crucial to understanding how safe a given provider will be for the consumer's business.

IV. Conclusions

E-learning systems use all the advantages of a cloud computing architecture: the infrastructure, the platform and the services. The characteristics of an e-learning system in cloud may differ depending on the type of cloud architecture: public, private or hybrid. Moreover, from this point the philosophy and the implementation of the system take different turns.

Some of the most popular functionalities of an e-learning system are e-mail accounts, individual web pages, forums, chats, learning platforms, class books and they all can be part of a cloud platform.

Also shown in [13], cloud computing brings to e-learning a great deal of security and portability by improved improbability (it is very difficult to determine where is the data stored), virtualization (the data is virtual replicated so the total loss of information is almost impossible), centralized data storage (no data is stored on the student's computer) and monitored data access (the security has to apply only to the entry points in the cloud).

This paper presents some preliminary researches of the project PN II, TE Program, Code 332: "Informatics Solutions for decision making support in the uncertain and unpredictable environments in order to integrate them within a grid network", financed within the framework of People research program.

References

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