[Computer Communications and Networks] Continued Rise of the Cloud || Cloud Computing Environment for e-Learning Services for Students with Disabilities

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  • Chapter 14Cloud Computing Environment for e-LearningServices for Students with Disabilities

    Aleksandar Milic, Konstantin Simic and Milo Milutinovic

    Abstract This chapter discusses design of cloud computing environments for e-learning services and applications for students with disabilities. The main idea isto expand the corpus of e-learning services adjusted for students with disabilities.The rationale is that e-educational systems are becoming more complex and educa-tional institutions need a new solution for deploying e-learning services. The cloudcomputing environment gives a new perspective to educational process in terms ofusage of educational applications, software, and system for e-education. Regardlessof the rapid development of information and communication technologies, there is alow level of inclusion of students with disabilities into the education process. There-fore, in this chapter the authors present a model of cloud computing environment forproviding e-learning services developed with respect to the needs of students withdisabilities. The model includes a variety of services, applications and componentsintegrated into the e-learning Web portal. These services provide numerous features:a choice of different types of teaching materials, an integration of interactive voiceresponse system within the learning management system, a mobile messaging ser-vice, etc. As a proof of the concept, a number of components of the model wereimplemented for students with disabilities within the Laboratory for e-business, Fac-ulty of Organizational Sciences, University of Belgrade. Results and our impressionsare presented.

    Keywords Cloud computing E-learning services E-learning Students withdisabilities E-education Disability

    A. Milic () K. Simic M. MilutinovicFaculty of Organizational Sciences, University of Belgrade,Jove Ilica 154, Belgrade, Serbiae-mail: milic@elab.rs

    K. Simice-mail: kosta@elab.rs

    M. Milutinovice-mail: milosm@elab.rs

    363Z. Mahmood (ed.), Continued Rise of the Cloud, Computer Communicationsand Networks, DOI 10.1007/978-1-4471-6452-4_14, Springer-Verlag London 2014

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    14.1 Introduction

    The ability to provide access to services and information 24 h a day, seven daysa week, is an emerging force today. Nowadays, higher education institutions areturning attention and resources to provide information and services on-line, andto use technology for improvement of the educational process. As a result, the e-educational system is revolutionized. In this new age, a good e-educational systemis an accessible e-educational system. A good e-educational system needs to have animmediate access to pertinent information.

    Further, information and communication technology (ICT) changes the educa-tional systems and their possibilities, thereby enabling an educational process to beoffered in way that responds to students needs and demands. The ICT is a tremen-dously valuable tool for encouraging the development, inclusion, and participationof collectives traditionally excluded from several areas of social and cultural life.This feature has enabled higher education institutions to include groups of studentswith disability to participate in the general curriculum and to successfully achieveacademic success. According to the World Health Organization (WHO), a disabilityis any restriction or lack (resulting from any impairment) of ability to perform anactivity in the manner or within the range considered normal for a human being.

    A very important topic nowadays is the issue of designing new educational ser-vices and adjusting current educational services to suit the needs of a disabled student.While the amount and type of accessible information increases, learning environ-ments, which offer the same content to all participants, and the same navigationaloptions, cannot satisfy the demands [1]. The problem is that the learning materialdoes not take into consideration the studentspersonal learning needs [2, 3]. Becauseof the learning environments limitations, there is a need for a transition from Web-based learning environments, which are developed with a motto, such as One sizefits all, to an adaptive Web-based learning [1, 4, 5].

    With a huge growth in the number of users, services, education contents, andresources, e-learning systems become more and more large-scale. One of the basicproblems in developing the environment for an e-education system is how to providescalability and reliability of educational applications and services. One of the possiblesolutions is infrastructure based on the cloud computing concept.

    This chapter discusses one possible approach to providing e-education servicesfor a student with disabilities. The developed model is based on the cloud computinginfrastructure. The model includes all services necessary for the inclusion of stu-dents with disabilities. The rest of the chapter is organized as follows: in the secondsection, a theoretical background of cloud computing and implemented e-educationservices for people with disabilities is given; the third section describes the differentapproaches for delivering e-learning services through cloud computing; in Sect. 14.4a model for the usage of e-learning services for students with disabilities throughcloud computing is proposed. Section 14.5 gives details on the realization of theproposed model within the e-learning system of the Laboratory for e-business atthe University of Belgrade. The next Sect. 14.6 discusses benefits from the devel-oped cloud computing services that students with disabilities can achieve. Finally,concluding remarks are given.

  • 14 Cloud Computing Environment for e-Learning Services . . . 365

    14.2 Theoretical Background

    14.2.1 E-Learning and Cloud Computing

    The majority of educational institutions own a computer centre which is designed andbuilt specifically for their own use. The efficiency of the existing resources representsa problem. The capacity of computer centre gradually becomes inadequate to meetthe demands of scientific research and educational activities, while at the same timeit becomes expensive to maintain. In each semester students mostly require the mostmodern hardware with specific software requirements for their laboratory exercisesand practical projects. Therefore, a low utilization of available resources requires adifferent approach to the implementation of infrastructure systems for e-learning.

    The best solution that information technologies could provide to users at highereducation institutions and to their computer centers is the development of an infor-mation technology (IT) infrastructure model based on the cloud computing concept.The concept of cloud computing is a business model and technology platform, whichis the result of evolution and convergence of many seemingly independent computingtrends. The cloud computing infrastructure for educational institutions allows for anefficient usage of the existing resources and gives a new perspective to scalability andreliability of educational applications, software, and a system for e-education. Thecloud computing concept and its characteristics can help higher education institu-tions improve productivity and enhance hardware and software resource managementwhich are necessary to provide e-education features, scientific and research activities,and student projects [6].

    The IT infrastructure of a higher education institution is a set of hardware, soft-ware, computer network, associated facilities meant to provide modern services andnetwork resources, the Internet connection and communication with other scientificresearch and higher education institutions, to promote scientific research and edu-cational processes. A majority of resources in the e-learning system are deployedand assigned for some specific tasks or services, and physical machines are usuallystacked simply and exclusively. With the growth of resources, the utilization of theseresources becomes another problem. During the education process a large amount ofteaching material is generated, which further aggravates the available resources. Oneof the biggest problems in the implementation of IT infrastructure is a competitiveaccess to shared resources in the higher education institution.

    14.2.2 People with Disabilities

    Developing learning environments and systems which provide education while sat-isfying the individual differences, such as learning styles, learning preferences,interests, etc. can be very beneficial. These environments/systems utilize differentsolutions, such as various teaching strategies to lessen the specific learning disability

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    [7]. People with disabilities face many difficulties in their everyday lives, dependingon the type of their disability. They are frequently the subjects of discrimination.Students with disabilities often have problems related to accessibility of teachingmaterials. Adequate categorization of people with disabilities can be used to preventthis discrimination of people with disabilities.

    When the literature is reviewed, it can be seen that classifications of specificlearning disabilities are expressed differently by different researchers. The mostfrequently used classifications of computer learning disability include visual im-pairments, hearing impairments, motor impairments, and cognitive impairments.Opposing these classifications, some specialists [8, 9] claim that specific learningdisabilities can vary from one child affected to another, and such disability can beobserved in a couple of areas and in some children, which cannot be classified. Thesedisabilities are briefly introduced in the following:

    Visual Impairments The visual impairments include:

    Total blindness: People who are totally blind cannot see at all; therefore, when ac-cessing the Internet or using computerized equipment, these individuals typicallyrely on screen reader devices.

    Low vision: People with low vision can see images; however, they cannot seemost images clearly.

    Color blindness: People with color blindness have difficulty in perceiving certaincolors and/or combinations of colors. These individuals may, however, have nodifficulty seeing black and white images or varying shades of grey [10].

    Hearing Impairments Hearing impairment disabilities vary in type and severity.People who have a hearing impairment may have a diminished ability to hear certainfrequencies (pitches), or they may have difficulty hearing at all frequency levels.

    Motor Impairments Some learners with motor impairment disabilities may havelimited use of their hands; others may not be able to use their hands at all. Condi-tions that may lead to a motor impairment disability include arthritis, amputation,birth defects, cerebral palsy, essential tremor, loss or damage of limbs, muscular dys-trophy, multiple sclerosis, spina bifida, spinal cord injury, neurological conditions,paralysis, and Parkinsons disease. Hudson [11] maintains that individuals who havemotor impairment disabilities commonly experience difficulties accessing computerkeyboards and mice; therefore, they often rely on special assistive technologies inorder to interact with a computer.

    Cognitive Impairments Cognitive impairments involve a wide variation of memory,perception, problem-solving, and conceptualizing challenges. Cognitive impair-ments are often attributed to conditions, such as autism, brain injury, cerebralpalsy, epilepsy, mental retardation, or neurological impairment [12]. Cognitiveimpairments can also include developmental disabilities, pervasive developmentaldisorders, Rett syndrome, and Williams syndrome [13].

  • 14 Cloud Computing Environment for e-Learning Services . . . 367

    Students with learning disabilities constitute the largest group of students withdisabilities at the college level. Some authors [14] suggested the need for new ed-ucational materials to develop students thinking ability, increase their motivation,and assess their learning. Carnine [15] and Ellis [16] advocate focusing teachingstrategies and instructional materials for all students on developing higher orderthinking processes. Rieth and Polsgrove [17] discuss three models for creating acurriculum for students with learning disabilities. Their goals include enabling stu-dents to better process information, improving their coping and problem-solvingskills, developing their interpersonal skills, and enabling them to establish socialsupport networks. Classroom simulations promote all four of these goals and couldbe effectively utilized in any of the three models discussed [18].

    14.3 Approaches to Delivering e-Learning Services to Studentswith Disabilities

    To bring services to people with disabilities, there are two commonly utilized ap-proaches. The first approach involves the utilization of an assistive technology. Thesecond approach involves the utilization of a design principle referred to as theuniversal design.

    14.3.1 Universal Design

    The term universal design was coined in the 1970s as an architectural concept formaking facilities accessible to all persons without the help of special assistance ordevices. Since that time the universal design concept has been adopted by many addi-tional fields including the computer industry, telecommunications, and informationsystems [19]. Universal design can be defined as the theory and practice pertainingto design, development, and implementation of communication, information, andtechnology products and services that are equally accessible to individuals who aredisabled.

    The Universal design for learning (UDL) is a research-based model for curriculardesign. The model ensures participation in the higher education institution programfor all students, including those with disabilities. The UDL offers options for howeducational resource is presented, how students respond or demonstrate their knowl-edge and skills, and how students are engaged in learning. The UDL implementationprovides the opportunity for all students to access, participate in, and progress in thehigher education institution curriculum by reducing barriers to instruction.

    The UDL addresses three learning networks within a broadly defined concept ofcurriculum that includes goals, materials, methods, and assessment [20]. Accordingto the following three UDL principles, each area of the curriculum should providemultiple, varied, and flexible options for representation, expression, and engagement:

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    Principle 1: It provides multiple means of representation (recognition network).Present information and content in different ways.

    Principle 2: It provides multiple means of action and expression (strategic net-work) and differentiates the ways in which students can express what theyknow.

    Principle 3: It provides multiple means of engagement (affective network) andstimulates interest and motivation for learning.

    Section 508 Standards [21] defines assistive technologies as any item, piece ofequipment, or system, whether acquired commercially, modified, or customized,that is commonly used to increase, maintain, or improve functional capabilities ofindividuals with disabilities.

    14.3.2 Assistive Technology

    In the context of Web accessibility assistive technologies include various hardwareand software solutions that improve the life quality of the people with motor andhearing impairments and those with sensory and mental disabilities. Some examplesare electronic aids, such as special keyboards, alternative commands, and auxiliarymeans for communication, such as ergonomic aids and specific software. Thesemodern technical aids and adapted software enable persons with disabilities to beindependent and to communicate.

    Assistive technologies can be classified into the following groups:

    Aids for Blind Persons These are:

    Voice program that includes two components: screen reader and speech synthe-sizer. Screen reader transforms users actions and screen content into text, whilesynthesizer transforms text into voice. One of the most used readers worldwideis job access with speech (JAWS).

    Braille display is a monitor for blind persons that presents text in Braille letters. Braille keyboards can replace standard keyboards. They contain the same keys

    as those on the typewriter for blind persons: Braille typewriter, and some otheradditional keys for navigation.

    Aids for Weak-Eyed Persons These are:

    Software for enlarging content on the screen with or without voice commands Keyboards with big letters for the weak-eyed Special keyboards, adaptable keyboards, mini keyboards, keyboards with

    enlarged keys, etc. Special mice, mice with adapted shape, etc. Touch screens

    Web accessibility should be perceivable, operable, understandable, and robust. Ifany of the principles are not taken into account, some users will not be enabled toaccess the content.

  • 14 Cloud Computing Environment for e-Learning Services . . . 369

    Perceivable means that all information and components on a page have to benotable and accessible in the way the user would like. Non-textual content, suchas images, audio, and video content, have to be visible, i.e., the user can see themin a proper way. For instance, for those who cannot hear, the content should bereadable; for those who cannot see, the content should be available using someother non-visual media.

    Operable means that link both navigation elements and user interface elementsare designed in the way that is useful for all users, i.e., they should be operable.Each element on the page has to be available via the keyboard. Users should begiven enough time to read and explore the content, except in the case of realtime operations, such as taking tests and auctions. Users should be provided withadequate support when they explore the Web page content, search for information,and determine position within site.

    The principle of understandability could be explained as a principle that providesa clear and understandable content presentation. The content has to be readableand predictable, i.e., Web pages work in the common way (opening pages in newtab or window, etc.). Further, support for users should be ensured. For instance,when the user fills a form, the system should notify the user whether some fieldhas been omitted, which field it is and give more explanations related to the properfilling of the form.

    Robustness is a concept that implies a high level of compatibility between pagesand user agents, including auxiliary technologies. All the elements should havea start and the last tag, have to be nested according to specification and must notcontain double attributes.

    14.4 A Model of Cloud Infrastructure for E-Learning

    Cloud computing refers to providing and using computational resources via theInternet [22]. It enables an access to technology in the form of services availableon demand. Cloud computing is an area of computing that refers to providing userswith highly scalable IT capacities as services via the Internet [23]. It is an abstract,scalable and controlled computer infrastructure that hosts applications and servicesfor end users. Services and data coexist in shared and dynamically scaled set ofresources [24].

    Applying cloud computing in higher education institutions improves efficiency ofthe existing resources usage, as well as reliability and scalability of software toolsand applications for e-education. Given the fact that most of resources are strictlyallocated to applications, physical machines are used for application, or particulartasks that are to be executed on that particular machine. If a system becomes busy andoverloaded, problem of scalability will be solved by adding new physical resources.Introducing new resources implies a significant increase in costs. Given this fact, itis necessary to find some other way of solving the problem of scalability and usageof resources. Simultaneous access to common resources is one of the most important

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    problems in using the IT infrastructure. Cloud computing can bring a new value toan e-education system, because educational services can be delivered in a reliableand efficient way.

    Basic components of the faculty e-education model are:

    Services for e-education (identity management system, e-mail, learning manage-ment system, document management system, customer relationship management,portal services, etc.)

    Software componentsmodular object oriented developmental learning environ-ment (Moodle), OpenNebula, open lightweight directory access protocol (LDAP),Apache, MySql, etc.

    Network and hardware infrastructure Users (students, non-teaching staff, etc.)

    14.4.1 Network Infrastructure

    Before developing the model of a cloud computing infrastructure it is necessary tobuild a network infrastructure that is suitable for e-learning. Network infrastructureis mandated to provide information, communication services, and the Internet con-nection for teachers, students, and external partners. Network infrastructure has toprovide a basis for the implementation of the e-education and scientific research ofhigh availability, scalability and reliability. In addition to services for employees andstudents, the system must provide support for collaboration with partners and exter-nal partners in distributed research teams. The primary tasks network infrastructurehas to meet are flexibility of the information system and a high level of security.Further, the infrastructure should enable quick, easy, and inexpensive installation ofnew hardware systems and software using the concepts of cloud computing.

    Part of the network infrastructure should be implemented as a common networkinfrastructure. The other part of the network infrastructure should be a virtual networkinfrastructure in the private cloud.

    All users of the service can be classified into the following categories:

    Employees have the highest level of administrative rights and privileges of allservices.

    Associates have a smaller set of privileges. Students have access to the set of student services.

    For the design and implementation of the computer network hierarchical model isused. This model is based on the principles of hierarchy and modularity. By applyingthis model complex network is divided into layers, defining the specific functions ofeach layer. The conceptual computer network architecture is shown in Fig. 14.1.

    The core layer is the backbone of the network and at the same time the mostcritical place in the network. It provides connectivity between the distribution layerdevices, and therefore high availability and redundancy are very important. Sincethis layer aggregates the traffic from all the devices of the distribution layer devices

  • 14 Cloud Computing Environment for e-Learning Services . . . 371

    Fig. 14.1 Conceptual logicnetworks scheme

    implemented at the central layer (routers and switches), it must support high datarates with low latency. On this layer, the security issue is of great importance. Pro-cessing large amounts of data, as well as connections to the Internet require theimplementation of high-performance devices on this layer.

    The distribution layer is the interface between the core and access layers. Therole of this layer is to provide aggregation of data from the access layer beforeforwarding these data to the core layer. The distribution layer controls the flow oftraffic using the policy and defining broadcast domains, which can be achieved byimplementing routers or virtual local area networks (VLAN). On this layer, there arehigh-performance devices. In order to achieve a high degree of availability, redundantdevices are implemented. Part of the distribution layer is implemented as a virtualnetwork infrastructure in the cloud.

    The access layer is the interface to end users and also represents the connectionof user devices with the rest of the network. In addition to user devices (computers,printers, IP phones, etc.) at this layer the routers, switches, hubs, and wireless accesspoint may also be included. The main task of this layer is connecting to a networkand access control in order to define which devices have access rights and the rightof communication over the network.

    The firewall/network address translation (NAT) is a software or hardware part ofnetwork infrastructure that controls the incoming and outgoing network traffic. Themain task of this part of the network is to control packets based on a defined set ofrules. The NAT is the process of modification of IP addresses in the IPv4 headerwhen passing through the routing device.

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    The cloud infrastructure includes part of the distribution and access layers of thecomputer network. This approach allows for the further development of educationaland research services in the cloud.

    The benefits of implementing the hierarchical model are numerous. The hierar-chical model successfully solves the problem of excessive broadcast traffic on thenetwork, thereby reducing the central processing unit (CPU) load of the networkdevices. Also, the cost of implementing computer network based on a hierarchi-cal model is reduced. For each layer, devices with clearly defined functionality areplanned, thus avoiding the purchase of expensive equipment with superfluous func-tionality. The principle of modularity makes the process of the system design simple.For that reason, network testing and troubleshooting in the network is simplified be-cause the entire network is seen as a set of layers. The process of network maintenanceand design changes in the hierarchical model is much easier to implement, since inthis case the changes in the network affect a small number of devices and services,as opposed to the flat network.

    14.4.2 Cloud Computing Infrastructure

    A developed environment for teaching and learning is based on a private cloudmodel. The main task was to deliver a reliable, secure, fault-tolerant, sustainable,and scalable infrastructure that enables efficient learning. A logical architecture ofthe implemented cloud computing infrastructure is shown in Fig. 14.2.

    Network services have to provide more flexibility of the IT infrastructure while atthe same time preserving a safe network environment. The limitations encounteredin the implementation of network services include a heterogeneous network environ-ment, the security access and links between different identities, multiple passwords,and a user account life cycle. Overcoming these constraints in the development ofnetwork services puts the focus on the entire process of managing digital identities.

    The process of managing the information on the digital identity of entities inorder to control access to resources is commonly referred to as identity management.In order to define a good structure of the directory for identity management, it isnecessary to define the user roles and privileges in the system. Every user withinthe model has a set of defined privileges in a specific sub-environment, in a specificcontext and for a specific service. The main problem of integration in a heterogeneousenvironment is to provide a unique method for identification and authentication ofsystem users.

    Numerous research works have proved that security, digital identity, and accessmanagement are essential for a successful deployment of infrastructure for e-learning[25, 26, 27]. For this set of tasks, the LDAP is chosen as a directory service. Users usethe same credentials to access different services. Depending on usersroles and needs,specific cloud services are provided through an appropriate deployment model:

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    Fig. 14.2 Logical architecture of cloud computing infrastructure

    Software as a service (SaaS)is provided mainly to teachers and students. Theseservices include the software necessary for the realization of e-learning (e.g., Moo-dle, communication tools, etc.) and specific solutions necessary for the realizationof the teaching process (e.g., interactive voice response; IVR system).

    Platform as a service (PaaS)is provided to teachers and students who need toteach and learn subjects that include using software tools that cannot be distributedto every student (e.g., students do not own the required hardware).

    Infrastructure as a service (IaaS)is managed by administrators and can beoffered to a universitys departments for developing their own virtual laboratories.

    There are several open source packages that take a holistic approach and integrateall of the necessary functionality into a single package (virtualization, management,interfaces, and security). When added to a network of servers and storage, thesepackages produce flexible cloud computing and storage infrastructures (IaaS). TheOpenNebula is issued under the Apache license. It supports private cloud construc-tion, as well as the idea of hybrid clouds. A hybrid cloud permits combining a privatecloud infrastructure with a public cloud infrastructure (such as Amazon) to enable

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    even higher degrees of scaling. After analyzing different reports found in the litera-ture [28], one can conclude that the OpenNubula is a suitable solution to deployingthe private cloud of an educational institution.

    The architecture of the private cloud is based on the OpenNebula. The OpenNebulais a tool that enables on-premise IaaS clouds in the existing infrastructures. A privatecloud uses the OpenNebula services for accessing the virtualized environment. TheOpenNebula has a set of pluggable modules to interact with specific middleware ofthe Cloud infrastructure (e.g., virtualization hypervisor, cloud services, file transfermechanisms, or information services). These adaptors are called drivers. Services forthe access to a virtual environment provide an interface for monitoring, migrating andmanaging virtual machines (VMs). The OpenNebula drivers are the core componentsof the infrastructure and only the administrators have the privileges to manage them.The services for managing the virtualized infrastructure can be accessed by otherapplications in the system. User credentials are stored in the OpenLDAP. Everyuser can save their VMs using a system for distributed file management, NetworkFile System.

    The primary goal of a private cloud implementation is to provide users with runof virtualized infrastructure, environment, and services. Virtual infrastructure man-agement system automates, coordinates, and integrates the existing solutions fornetworking, storage, virtualization, monitoring, and user management. The key com-ponents of the model enable an efficient work with VMs. VMs are put on the imagerepository and could be moved and run on users demands. The system componentfor VM management enables achieving scalability and reliability of implementedservices on the VM. The private cloud layer (driver) that enables access by usingvirtualized infrastructure includes: (1) Virtual machine manager (VMM) driver usedfor creation, control, and tracking VM (2)Transfer drivers used for transmission,replication, removing and creating VM images (3) Information driver that controlsand tracks machines and other hardware performances.

    Security is one of the big concerns in this model. The main goal that securityshould fulfill is creating a highly available system and a secure environment. Thephysical security that makes the system resistant to attacks created at theVM, requiresa strict separation between the physical environment and the VM. The only accesspoint to virtual environment is delegated to the VM that is connected to a physicalnetwork interface. By using a firewall, the system is protected from unauthorizedaccess to virtual networks and to the system itself. The firewall disables commu-nication between VMs in configured virtual networks. During the VM exploitationfailovers could occur, thus the work of the whole system could be threatened. In orderto quickly recover the system, requirement for distributed file system (DSF) is nec-essary. The DSF possesses a defined fault tolerant, realized through data replicationon different physical machines.

    14.4.3 Services for E-Education

    A key part of the described model is the Moodle LMS learning management systemas the aggregator and integrator of all components and services. The Moodle LMS

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    provides services for collaboration and communication which do not meet all therequirements of student needs. The LMS is built as a VM within the private cloudthat is managed through the administrative part of the OpenNebula interface. ThisVM has certain hardware resources and can be expanded during the work or moved byintroducing a new, more powerful machine. Students access the portal and resourcesonly within the educational research resource pool. Logging into the portal enablesthe use of student services. All access rights for e-education services are written inLDAP. Students and employees can use an interactive voice response machine andreceive an SMS notification about courses they are subscribed to. The model enablesstudents to exercise developing and managing VM for hosting, thus they can getpractical knowledge from different areas.

    Further, in order that the students should try out all the advanced techniquesand technologies it is necessary to ensure the use of different operating systems,development platforms, software tools, database management tools, Web servers,browsers, etc. Therefore, using a developed cloud computing infrastructure eachstudent accesses a VM that hosts a required image. After the closure of work, thestudents results can be saved for further work or analysis. The advantage of thisapproach is that the student needs only an Internet connection for work and a completehardware and software necessary to successfully master the matter are provided at ahigher education institution.

    14.4.4 Network Performance Monitoring System

    The primary task of the network performance monitoring system is to oversee andmonitor the parameters of network devices and services. Considering the structureand characteristics of the network infrastructure, it was decided to implement net-work monitoring using the simple network management protocol (SNMP). [29]. Fornetwork devices, it is necessary to monitor the network traffic on interfaces and theCPU usage. For servers andVMs, it is necessary to monitor the following parameters:

    Traffic on interfaces Processor availability Memory consumption Number of processes Number of logged users

    In order to monitor the network parameters, in the computer network of the laboratoryfor e-business Cacti application was implemented. Cacti application is installed in aVM on a server with a CentOS 6.4 operating system. The access to the applicationis made via the Web interface.

    The main task of the Cacti application is to monitor the parameters of networkdevices and servers (Fig. 14.3). The SNMP protocol is mainly used for collecting datafrom network devices (routers, switches, etc). For security reasons, the SNMP accessshould be limited to the management station, which is implemented by access lists.

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    Fig. 14.3 CPU usage on one of the servers

    14.5 Implementation of Application Services in E-Education

    According to numerous research works, the Moodle is one of LMSs with thelargest number of functionalities and services [30, 31]. The Moodle is flexible forimplementing new components and integration with other systems and technologies.

    The laboratory for e-business, at the Faculty of Organizational Sciences, organizesits courses at all levels of study, using a blended learning concept [32]. More than900 students have access to more than 100 online courses, created within the e-learning system management Moodle LMS. The Moodle is an open-source systemfor managing teaching and learning via theWeb. It is widely used by many universitiesand instructors. In the scope of the Moodle courses, we use a lot of additional softwareand applications.

    Problems arise when a large number of students simultaneously access the system(taking tests, uploading or downloading large amounts of data, setting homework,etc.). At these moments, the server load is near the maximum and then it is necessaryto provide the scalability and reliability. In order to overcome these problems andimprove the system performances, the Department for e-business has implemented acloud computing infrastructure described in the previous section. The infrastructureincludes 160 CPU with more than 4TB of memory. The implemented infrastructurebased on cloud computing enabled an efficient and scalable work of teachers andstudents.

    According to the four principles ofWeb accessibility and according to the proposedmodel, some adjustments were introduced in scope of the laboratory for e-business,Faculty of Organizational Sciences, Belgrade. These adjustments include an adap-tation of current services and teaching materials, as well as customization of designof the e-learning Web portal. This e-learning system is realized by using the Moodlelearning management system. Customizing the portal to students with visual impair-ments is performed in several ways. Each non-text element is described in detail andalso students are able to change the theme of the portal (font, colors, element layout,etc.). In Fig. 14.4, an example is given of the image which has additional descrip-tions and can make materials more accessible to students who are blind by providing

  • 14 Cloud Computing Environment for e-Learning Services . . . 377

    Fig. 14.4 Image with additional descriptions

    Fig. 14.5 Choosing betweendifferent text sizes

    meaningful alternate or long descriptions (alt tags) for each non-text element on thepage. Alt tags are a descriptive text that shows up when a mouse-arrow hovers overa non-text element. Screen-reading devices are able to read these image descriptionsto students.

    Students are able to choose between four available different Web portal themes.They are also able to choose one of two available text sizes for each theme. Usedthemes are customized for people with low vision and color blindness. In Fig. 14.5,an example of choosing between different text sizes is shown.

    In addition to customizing the design of the current e-learning portal, the systemis extended with a new IVR service. The infrastructure for this system is shown inFig. 14.6. This service helps students with visual and motor impairments. A studentwith special needs chooses whether he/she wants to take a normal or accessible testand whether he/she has visual or motor problem(s). These data are saved into theMoodle database, as well as the phone number which the student will use for access-ing the system. While taking the test, the student is being identified by comparing thephone number which is used for accessing the system with the phone number storedin the database. The system checks if the student has the privilege for accessingthe test and if it is the case, the student can start the test. For a student with visualproblems, the voice synthesizer reads the questions. Students answer the questionsby pressing the appropriate keypad key. All questions are previously prepared andthere are four available answers. Only one answer is a correct one.

    Our IVR solution [33] can also be used by students with motor impairment andby everyone, as well. Students with motor impairment may have a difficult time

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    Fig. 14.6 Infrastructure of an IVR system for e-learning

    interfacing with their computer. Therefore, the IVR in their case has a long timeoutof 30 s per question. The IVR also has a built-in basic speech recognition mechanism.All questions have four available responses. The student chooses only one response.Response can be given by pressing the appropriate key or by saying the response. Thespeech recognition mechanism is simple because the system distinguishes only fourwords (one, two, three, and four). If the student does not respond in the scheduledtime interval, all skipped or unanswered questions will be read again and the studentwill have another chance to answer them. After finishing the test, the result is read tothe student by the IVR system and it is stored in the Moodle database. The numberof accessing the test by a single student can be limited.

    The proposed model is appropriate because it allows a high-level scalability andreliability for e-learning services. Numerous researchers show [34, 35, 36] that in adynamic environment, such as learning environment, cloud computing represents amost convenient approach in developing infrastructure. The main reason why thereis no quantitative result or analysis of the presented model is the number of studentswith disabilities on our courses. Each year there are only a few students with someimpairment but nevertheless some trends can be noticed. Students with disabilitieschoose examinations and courses which are realized on the described platform. Fur-thermore, they participated in improving the platform through practical work on theirfinal examination.

  • 14 Cloud Computing Environment for e-Learning Services . . . 379

    There are a few problems which are identified. Our IVR solution for the speechrecognition engine shows some malfunctioning. Speech recognitions systems be-have well when it comes to the English words. For languages for which the speechrecognition system is not especially developed some problems occurred.

    14.6 Conclusion

    In this chapter we discussed new possibilities and solutions in the area of cloudcomputing. We used cloud computing in order to improve the development of the ITinfrastructure of a higher education institution. Cloud computing allows for a seam-less integration of all the components necessary for learning activities. A privatecloud was developed on the existing IT infrastructure. The main goal was to em-phasize the advantages and constraints of applying cloud computing in education. Asuccessful realization of teaching and learning processes requires the use of variousapplications and services.

    This research introduced a model of e-learning services developed with respect toneeds of students with disabilities. The key advantage of the suggested approach isthat it is designed to use the existing resources of an educational institution to providean integrated and high performance environment for teaching and learning of studentswith disabilities. The model includes various applications and components integratedinto the e-learning system. As a proof of the concept, a few components of the modelwere implemented for students with disabilities within the laboratory for e-business,the Faculty of Organizational Sciences, University of Belgrade.

    The study presented in this chapter demonstrates a measurable improvement ofthe system for e-learning for students with disabilities by introducing cloud servicesand integrating them with the Moodle Learning Management System. The resultsof the research showed that students achieved good results when studying in thee-learning environment improved with cloud computing technologies.

    Future research directions include the establishment of an inter-institutional ini-tiative for building a prototype of cloud computing infrastructure that can be shared,and organized for educational, scientific, and research purposes as well as for devel-oping a virtualization platform that can deploy different VMs on the fly on studentsrequests.


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    Part V Applications in Education and Other ScenariosChapter 14 Cloud Computing Environment for e-Learning Services for Students with Disabilities14.1 Introduction14.2 Theoretical Background14.2.1 E-Learning and Cloud Computing14.2.2 People with Disabilities

    14.3 Approaches to Delivering e-Learning Services to Students with Disabilities14.3.1 Universal Design14.3.2 Assistive Technology

    14.4 A Model of Cloud Infrastructure for E-Learning14.4.1 Network Infrastructure14.4.2 Cloud Computing Infrastructure14.4.3 Services for E-Education14.4.4 Network Performance Monitoring System

    14.5 Implementation of Application Services in E-Education14.6 ConclusionReferences


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