The Model, Architecture and Mechanism Behind Realcourse

Zhang, Jinyu; Li, Xiaoming

doi:10.1007/978-3-540-30566-8_73

Cited by 9 publications

(5 citation statements)

References 6 publications

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“…The ontology in this example is constructed according to the Computing Curriculum proposed by ACM/IEEE [7], where the knowledge system of information technology is categorized into three levels: Area, Unit, and Topic. The Area represents a sub-domain of the knowledge system that is used to organize, categorize, and describe the top level knowledge These three levels can make up the ontology of the Information Technology knowledge system, which has been applied to the University Course Online (realcourse in short) system [10] -a Grid based video stream online education service. The leaf nodes of the ontology are the direct parents of LO instances which are normally the titles of the courses or course components that can be freely selected by learners.…”

Section: B Organization Of the Learning Objects (Services)mentioning

confidence: 99%

An e-Curriculum Based Systematic Resource Integration Approach to Web-Based Education

Song¹,

Forsman²,

Yan³

2015

IJIET

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Abstract-With the rapid advancement of the web technology, more and more educational resources, including software applications for teaching/learning methods, are available across the web, which enables learners to access the learning materials and use various ways of learning at any time and any place. Researchers from both computer science and education are working together, collaboratively focusing on development of pedagogically enabling technologies which are believed to improve the infrastructure of education systems and processes, including curriculum development models, teaching/learning methods, management of educational resources, systematic organization of communication and dissemination of knowledge and skills required by and adapted to users. In this paper we address the following two aspects of systematic integration architecture of educational systems: 1) learning objects -a semantic description and organization of learning resources using the web service models and methods, and 2) learning services discovery and learning goals match for educational coordination and learning service planning.Index Terms-E-curriculum, learning object, e-learning, web based educational systems.

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Section: B Organization Of the Learning Objects (Services)mentioning

confidence: 99%

An e-Curriculum Based Systematic Resource Integration Approach to Web-Based Education

Song¹,

Forsman²,

Yan³

2015

IJIET

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“…Course Online Grid (realcourse in short) is a video stream service supported by a collection of physical servers distributed all over China [22]. Since its birth in April 2003, realcourse has been in non-stop operation for more than two years, in spite of some of the servers up-and-down, in-and-out from time to time.…”

Section: Course Online Gridmentioning

confidence: 99%

ChinaGrid and its impact to science and education in China

Jin

2005

2005 International Conference on Collaborative Computing: Networking, Applications and Worksharing

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Grid technology provides the mechanism for largescale sharing of computing resources, storage resources and equipments within virtual organizations crossing different administrative domains. ChinaGrid project, founded by Ministry of Education of China, is an attempt to achieve above goals by exploring the various resources on existing and well developed Internet infrastructure, CERNET (China Education and Research Network). In this paper, we introduce the current status of ChinaGrid project, and its driven requirements and architecture. The brief introduction of the design of ChinaGrid Support Platform, named CGSP, is also given. To illustrate the impact of ChinaGrid project, five different grid computing applications and its application supporting platform are discussed in detail.

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“…How ever, the system has experienced a major but smooth change in 2005 from Realcourse1.0 [1] to Realcourse2.0. The primary objective of Realcourse is to allow universities to share lecture videos in a cost-effective way and to deliver good performance of video playing.…”

Section: Introductionmentioning

confidence: 98%

“…For video file itself, which is normally large in size (about 100MB each), upon uploading, two servers are chosen to keep permanent copies of the file. Temporal copies (caches) of video files are generated among servers in a manner of "Copy on Demand in pipeline", that is, if the connected server does not have the requested video, it will fetch the video from either the original server or the backup server [1], and in the mean time deliver it to user.…”

Section: Introductionmentioning

confidence: 99%

Realcouse2.0: From Fully Connected Topology to Multiple Overlapping Stars

Zhang

2009

2009 Fourth ChinaGrid Annual Conference

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We present the second version of Realcourse. Realcourse is a cooperative Internet video publishing and delivery system used by more than thirty Chinese universities to share course videos. The design of Realcourse bears the following assumptions 1) the system is supposed to consists of hundreds of unreliable but controllable servers where temporal failures are common, permanent failures are rare, 2) videos are concurrently uploaded to local servers but their metadata are broadcasted to all servers, 3) users are connected to and served by local servers but should be able to watch all the videos in the system in a seamless and efficient fashion. Realcourse has gone through two versions. In Realcourse1.0, all servers were treated equal and fully connected by messaging channels. In order to maintain a consistent global directory among servers, each server informs all others of local update operations through the message channels. The fully connected server topology poses a great challenge to system management with respect to failures. To solve this problem, Realcourse2.0 adopts a server topology of multiple overlapping stars by 1) replacing direct broadcast with relayed-broadcast, in which message is first sent to a relay server and then forwarded to all other servers, 2) partitioning the global directory into sub-trees, each sub-tree is then fully replicated to a group of selected servers while groups may overlap with each other. This paper explains why such a change is necessary and how it was done. Realcourse has been operational since December 2003. Today, more than 5000 videos are served. We constantly observe about 10000 unique user IP addresses each day.

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The Model, Architecture and Mechanism Behind Realcourse

Cited by 9 publications

References 6 publications

An e-Curriculum Based Systematic Resource Integration Approach to Web-Based Education

An e-Curriculum Based Systematic Resource Integration Approach to Web-Based Education

ChinaGrid and its impact to science and education in China

Realcouse2.0: From Fully Connected Topology to Multiple Overlapping Stars

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