It combines grid technology with E-Learning, present an E-Learning architecture based on grid technology to support learning novel mode.. By using Grid Computing technology, this method
Trang 1F Li et al (Eds.): ICWL 2008, LNCS 5145, pp 314 – 321, 2008
© Springer-Verlag Berlin Heidelberg 2008
Platform in Grid Architecture
Tianding Chen
Institute of Communications and Information Technology, Zhejiang Gongshang University, Hangzhou 310018
chentianding@163.com
Abstract It combines grid technology with E-Learning, present an E-Learning
architecture based on grid technology to support learning novel mode By using Grid Computing technology, this method aims to integrate those unrelated
com-puters in schools to replace high level server as the teaching platforms of E-Learning Thus, not only the computer sources in schools can be fully used and applied, and moreover, constantly sharing the computer sources from other schools or associations as well as the computing capacities In this paper, a
pro-totype of E-Learning platform using grid environment is proposed, built up using a number of open source E-Learning software in a heterogeneous
envi-ronment In the future, using grid technology on E-Learning might be a new scheme We also expect the outcome and experiences of this research can
pro-vide reference to the schools that wish to develop E-Learning environment for saving the cost and time in developing a similar system
1 Introduction
Grid technology was originally conceived to provide support for applications belong-ing to scientific domains However, the grid is currently embarked on a maturation process derived from the definition of the Open Grid Services Architecture (OGSA) [1] which could allow the expansion of grid technology within new domains such as business and education At present, education and collaboration are emerging as very important application fields of grid technologies The use of grid technologies may enable access to large amounts of heterogeneous resources that can be employed for educational purposes This new scenario is called E-Learning Grid or Learning Grid [2][3][4][5][6]
In recent years, with the rapid development in communication and network tech-nologies, E-Learning has been popularized and become one of the most popular teaching methods in educational community Along with the gradual improvements found in network bandwidth and quality, real-time transmission of high-quality video and audio has become possible and true reality Because of these major transitions, conventional methods of school education have also followed this trend
E-Learning utilizes electronic devices to assist the education or training process, taking advantage of the internet or any other communication channel to connect other devices, to deliver information and knowledge This model of learning has many advantages with respect to traditional models: a better interaction between the learner and the learning resources he uses, i.e., the learning is not passive; Learning can happen anytime and anywhere, i.e., there are not boundaries tied to time and place; A
Trang 2tutor, or learner himself, is able to monitor the progress and to customize the learning experience basing on learner skills and preferences
In E-Learning research, it is a crucial problem the support of learning in scalable, open, dynamic and heterogeneous environments The scenario is a large scale and connected environment of Learning Management Systems, Learning Content Management Systems and virtual classroom systems of different organizations Grid computing has emerged as
an important new field, distinguished from conventional distributed computing by its focus on large-scale resource sharing, innovative applications and, in some cases, high-performance orientation [7] Grid technology address issues related to access provision-ing coordinated resource sharprovision-ing and problem solvprovision-ing in dynamic, multi institutional virtual organization [8] By adopting grid technology, it is possible a wide-scale learning resource sharing in heterogeneous and geographically distributed environments, the im-plementation of learning organizations in which different actors (teachers, learners), sharing a common target, are able to cooperate to obtain a result
2 E-Learning Systems and Grid Computing
With the rapid growth of the Internet and digital technologies, the web has become a powerful, global, interactive, dynamic, economic, and democratic medium of learning and teaching at a distance [9] E-Learning is the unifying term to describe the fields of online learning, web-based training, and technology-delivered instruction Rosenberg[10] defines E-Learning have three fundamental criteria: a E-Learning is networked, which makes it capable of instant updating, storage/retrieval, distribution and sharing of instruction or information; It is delivered to the end-user via a com-puter using standard Internet technology; It focuses on the broadest view of learning – learning solutions that go beyond the traditional paradigms of training
General E-Learning systems have four components: People, Authoring System, Run-Time System, and Learning Management System (LMS) [6] People in these systems are the learners and authors, while others may include trainers and administrators Au-thors (which may be teachers or instructional designers) create content, which is stored under the control of a LMS, and typically in a database Existing content can be up-dated, and it can also be exchanged with other systems A LMS is managed under the control of an administrator, and it interacts, with a run-time environment which is ad-dressed by learners, who in turn may be coached by a trainer These components of an E-Learning system can be logically and physically distributed
In current incredibly complex world of computational power, very high speed ma-chine processing capabilities, complex data storage methods, next-generation telecom-munications, new generation operating systems and services, and extremely advanced networking services capabilities, we are entering a new era of computing-Grid Comput-ing [11] Grid computComput-ing has emerged as a framework for supportComput-ing complex compila-tions over large data sets In general, grids enable the efficient sharing and management
of computing resources for the purpose of performing large complex tasks [12]
Although many academies have now adopted E-Learning for teaching, the software and hardware facilities that the academies use are very different It has become a cause of major difficulties in sharing the teaching resources with one another The technique of Web Services can integrate the different information system within the
Trang 3Fig 1 The Grid computing infrastructure
Grid to solve the above mentioned problem Therefore, the concept of this research is based on integrating Grid Computing with Web Services to build up an E-Learning platform [13] Figure 1 shows the concept of grid computing
3 Proposed E-Learning Grid Architecture
The architecture contains five layers from bottom to up, as shown in Figure 2 [14] The infrastructure layer, at the lowest layer, supports basic networking environment,
Fig 2 An E-Learning Grid Architecture
Trang 4including computing devices, networking and networking protocols etc Secondly, the basic service oriented architecture for implementing the basic web services related protocols such as XML, UDDI/SOAP/WSDL etc This layer provides the elementary connectivity, interoperation, reliability and flexibility for the layers on top of it As next layer, the grid middleware layer is the core of the architecture where the basic grid problems such as distribution, dynamic, open and cross-organization are re-solved The content layer is on top of grid middleware layer to store all of learning contents in our platform At last, the learning grid portal supports single user sign on the system In next subsections, brief introduction of these layers will be discussed Grid Middleware Layer is a crucial layer to build a grid environment and should be
on existing OGSA compliant middleware such as Globus Toolkit 4 (GT4) The Globus project provides open source software toolkit that can be used to build compu-tational grids and grid-based applications [15] It allows sharing of computing power, databases, and other resources securely across corporate, institutional and geographic boundaries without sacrificing local autonomy It implements services for Security Services, Resource Management, Information Services and Data Management in the grid The main functions of them are listed below
(1) Security Services
(2) Resource Management
(3) Information Services
(4) Data Management
Content Layer is on top of grid middleware layer to store all of contents in our plat-form [16] As above mentioned an E-Learning system needs a Learning Management System to store and manage its teaching content However, every LMS platform runs its own learning materials, which cannot be exchanged with those of other LMSs To deal with this problem, the U.S government launched the Advanced Distributed Learning Initiative (ADL) [17] is unifying E-Learning specifications emerging from the international standards organizations into a single specification referred to as the Sharable Content Object Reference Model (SCORM) SCORM aims to establish a mechanism for repeated use and sharing of courseware as a way to reduce the time and cost of developing courseware and to make courseware reusable and acceptable
to different LMSs
Learning Gird Portal is the unified entry for all grid platform users Users from dif-ferent organizations who logon it could share learning resources without knowing where they come from Moreover, the portal is responsible for assisting authenticated users when operating within the grid environment
4 Optimization on Grid Portal Structure
In a grid organization, the grid portal allows communication between the outside world and the grid The major function is to provide users with a web-based interface for the grid service and resources To make the grid portal run more efficient way, we use the web mining technology to adjust its framework To make it congregate users’ needs Web mining is a type of application of data mining and it is categorized into
“web content mining” and “web usage mining” Web content mining deals with sur-veying the contents of the web and it is mainly applied to analyzing web contents and
Trang 5reinforcing web-searching capability, such as a search engine Web usage mining mainly deals with analyzing the web users’ browsing behavior through web log, so that the web administrator will become aware of the operation of the website before modifying the system, for the purpose of more efficient operation [18]
Web Usage Mining suggests analysis of user’s browsing behavior through the web log It enables the web administrator to be aware of the operation of the website be-fore modifying the framework, for the purpose of more efficient operation Its appli-cation comes as follows:
(1) Analysis of web flow
In the web log, the title and size of a specific web and a specific access are duly registered and pattern for the web flow In the [19] study, variation of web flow in each day of the week is registered in the web log Analysis of it will become more applicable on the adjustment and planning of network bandwidth
(2) Improvement of web accessibility
By analyzing the web log, we have come to realize what popular websites and files are received more in an access rate Consequently, we can place those files in the Web Proxy server or cache server In the [20] study, we can analyze the web log and make
a forecast of the popular web pages to decide on its priority of the pages in Cache (3) Analysis or forecast of browsing behavior
This is a common subject being studied in Web Usage Mining Robert Cooley et
al [21] is one of the few experts that introduced the idea Other studies aim to im-prove or propose new algorithmic methods [22] [23] for more efficient analysis On the other hand, the web mining tool WUM [24] used in this study is theoretically based on aggregate tree, and MINT language that resembles SQL is used for analysis
of the web before reaching to the patterns that we are interested in
Data obtained through WUM analysis can be taken as a pattern, which comes from
a kind of a rule An example is that the browse from page A, page B to page C must follow a number of rules To locate the most beneficial one, other methods are needed In this case, we opt for the Greedy Algorithm
Greedy Algorithm is simply understood as: When we have a number of options, we will usually select the most beneficial one at sight [25] Figure 3 shows a simple route selection
Fig 3 A simple route selection
Suppose we are to choose the most popular route from V0 to V3, Greedy Algorithm would suggest 5 + 10 + 7 = 22, which is the common one This can not be an easy job every time The following Figure 4 explains why