Browsing by Author "Tsai, WN"

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A content management scheme in a SCORM compliant learning object repository
(2005-09-01)
Su, JM
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Tseng, SS
;
Wang, CY
;
Lei, YC
;
Sung, YC
With the rapid development of the Internet, e-learning systems have become more and more popular. For sharing and reusing teaching materials in different c-learning system, the Sharable Content Object Reference Model (SCORM) has become the most popular international standard among the existing ones. In an e-learning system, teaching materials are usually stored in a database, called the Learning Object Repository (LOR). In the LOR, a huge amount of SCORM teaching materials, including associated learning objects, will result in management problems in a wired/wireless environment. Recently, the SCORM organization has focused on devising ways to efficiently maintain, search. and retrieve desired learning objects in LORs for users. This effort is referred to as the Content Object Repository Discovery and Resolution Architecture (CORDRA). In this paper, we propose a management approach, called the Level-wise Content Management Scheme (LCMS), that can be used to efficiently maintain, search, and retrieve learning contents from a SCORM compliant LOR. LCMS includes two phases: the Construction phase and Search phase. In the former, the content structure of SCORM teaching materials (Content Package) is first transformed into a tree-like structure. called a Content Tree (CT), to represent each piece of teaching material. Based on Content Trees (CTs), the proposed Level-wise Content Clustering Algorithm (LCCAIg) then creates a multistage graph showing relationships among learning objects (LOs), e.g.. a Directed Acyclic Graph (DAG), called the Level-wise Content Clustering Graph (LCCG). The LCCAIg determines the relationships among LOs in different teaching materials by clustering all of the LOs for each level from bottom to top, according to a similarity measure. Moreover, a maintenance strategy is employed to rebuild the LCCG if necessary by monitoring the condition of each node within the LCCG. The latter employs the LCCG Content Searching Algorithm (LCCG-CSAlg) to traverse the LCCG and retrieve desired learning content with both general and specific LOs, according to queries sent by users in the wire/wireless environment. Some experiments have been done conducted to test the proposed scheme, and the results are reported here.
A performance study of CDPD
(1999-10-01)
Tsai, WN
;
Lin, YB
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資訊工程學系
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Department of Computer Science
Cellular digital packet data (CDPD) is a wireless extension to data networks, which utilizes the idle capacity (radio channels) of cellular systems. This paper studies the performance of the CDPD system to investigate how the CDPD traffic and the voice traffic affect the CDPD blocking probability. The results offer guidelines for the CDPD network planning. (C) 1999 Published by Elsevier Science Inc. All rights reserved.
Adaptive learning environment to meet pedagogical needs
(2004-11-01)
Su, JM
;
Tseng, SS
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Chen, CT
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Tsai, WN
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資訊工程學系
With the vigorous development of the Internet, e-learning systems have become more and more popular. Currently, to solve the issue of sharing and reusing teaching materials in different e-learning systems, several standard formats, including SCORM, IMS, LOM, AICC etc., have been proposed by international organizations. Among these international standards, the Sharable Content Object Reference Model (SCORM) has become the most popular standard in recent years. In the SCORM standard, Sequencing and Navigation (SN), which is based on the concepts of learning activities, defines the course sequencing behavior, which controls the sequencing, selecting and delivering of the course, and organizes the content into a hierarchical structure, namely, an Activity Tree (AT). For a large-scale learning activity, the Activity Tree will become too complex to manage and reuse, as will its sequencing behavior rules. Moreover, the lack of inter-relations among Activity Trees also makes reusing and integrating them hard. This implies that the scalability and flexibility of an adaptive learning system will be limited. Therefore, how to create, represent and maintain an AT and associated sequencing definitions is our concern. In addition, for a personalized learning environment, how to extend the structure of an AT with Pedagogical Theory has also become an important issue. Therefore, in this paper, we extend and modularize the structure of an AT by applying Pedagogical Theory and the concept of the Object Oriented Methodology, respectively. Thus, we first propose a novel model, the Instructional Activity Model (IAM), which is composed of related AT nodes. Each AT node in IAM is modularized as a learning unit with inter-relations and specific attributes, which can be easily managed, reused, and integrated. We also propose an AT Selection algorithm with a pedagogical strategy for traversing IAM in order to generate dynamic learning content for the learner. IAM with its scalability and flexibility can apply appropriate pedagogical theories to meet specific needs by means of extension scheme. Finally, we propose a systematic approach to fast and easily construction of IAM using traditional course resources.
Constructing SCORM compliant course based on high-level Petri nets
(2006-01-01)
Su, JM
;
Tseng, SS
;
Chen, CY
;
Weng, JF
;
Tsai, WN
With rapid development of the Internet, e-learning system has become more and more popular. Currently, to solve the issue of sharing and reusing of teaching materials in different e-learning system, Sharable Content Object Reference Model (SCORM) is the most popular standard among existing international standards. In SCORM standard, the Sequencing and Navigation (SN) defines the course sequencing behavior, which controls the sequencing, selecting and delivering of a course, and organizes the content into a hierarchical structure, namely Activity Tree (AT). However, the structures with complicated sequencing rules of Activity Tree (AT) in SCORM make the design and creation of course sequences hard. Therefore, how to provide a user-friendly authoring tool to efficiently construct SCORM compliant course becomes an important issue. However, before developing the authoring tool, how to provide a systematic approach to analyze the sequencing rules and to transform the created course into SCORM compliant are our concerns. Therefore, in this paper, based upon the concept of Object Oriented Methodology (OOM), we propose a systematic approach, called Object Oriented Course Modeling (OOCM), to construct the SCORM compliant course. High-Level Petri Nets (HLPN), which is a powerful language for system modeling and validation, are applied to model the basic sequencing components, called Object-Oriented Activity Tree (OOAT), for constructing the SCORM course with complex sequencing behaviors. Every OOAT as a middleware represents a specific sequencing behavior in teaming activity and corresponding structure with associated sequencing rules of AT in SCORM. Thus, these OOATs can be efficiently used to model and construct the course with complex sequencing behaviors for different teaming guidance. Moreover, two algorithms, called PN2AT and AT2CP, are also proposed to transform HLPN modeled by OOATs into a tree-like structure with related sequencing rules in Activity Tree (AT) and package the AT and related physical teaming resources into a SCORM compliant course file described by XML language, respectively. Finally, based upon the OOCM scheme, a prototypical authoring tool with graphical user interface (GUI) is developed. For evaluating the efficiency of the OOCM approach compared with existing authoring tools, an experiment has been done. The experimental results show that the OOCM approach is workable and beneficial for teachers/ instructional designers. (c) 2005 Elsevier B.V. All rights reserved.
Learning portfolio analysis and mining for SCORM compliant environment
(2006)
Su, JM
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Tseng, SS
;
Wang, W
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Weng, JF
;
Yang, JTD
With vigorous development of the Internet, e-learning system has become more and more popular. Sharable Content Object Reference Model (SCORM) 2004 provides the Sequencing and Navigation (SN) Specification to define the course sequencing behavior, control the sequencing, selecting and delivering of course, and organize the content into a hierarchical structure, namely Activity Tree. Therefore, how to provide customized course according to individual learning characteristics and capabilities, and how to create, represent and maintain the activity tree with appropriate associated sequencing definition for different learners become two important issues. However, it is almost impossible to design personalized learning activities trees for each learner manually. The information of learning behavior, called learning portfolio, can help teacher understand the reason why a learner got high or low grade. Thus, in this paper, we propose a Learning Portfolio Mining (LPM) Approach including four phases: 1. User Model Definition Phase: define the learner profile based upon existing articles and pedagogical theory. 2. Learning Pattern Extraction Phase: apply sequential pattern mining technique to extract the maximal frequent learning patterns from the learning sequence, transform original learning sequence into a bit vector, and then use distance based clustering approach to group learners with good learning performance into several clusters. 3. Decision Tree Construction Phase: use two third of the learner profiles with corresponding cluster labels as training data to create a decision tree, and the remainings are the testing data. 4. Activity Tree Generation Phase: use each created cluster including several learning patterns as sequencing rules to generate personalized activity tree with associated sequencing rules of SN. Finally, for evaluating our proposed approach of learning portfolio analysis, an experiment has been done and the results show that generated personalized activity trees with sequencing rules are workable and beneficial for learners.
Location tracking with distributed HLR's and pointer forwarding
(1998-02-01)
Lin, YB
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Tsai, WN
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資訊工程學系
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資訊科學與工程研究所
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Department of Computer Science
Location tracking operations in a personal communications services (PCS's) network are expensive. A location tracking algorithm called pointer forwarding has been proposed to reduce the location update cost, The key observation behind forwarding is that if users change PCS registration areas (RA's) frequently, but receive calls relatively infrequently, it should be possible to avoid registrations at the home-location register (HLR) database by simply setting up a forwarding pointer from the previous visitor-location register (VLR), Calls to a given user will first query the user's HLR to determine the first VLR, which the user was registered at, and then follow a chain of forwarding pointers to the user's current VLR. To reduce the "find" cost in call delivery, the PCS service provider may distribute HLR databases in the network. This paper integrates the concept of distributed HLR's with pointer forwarding, and the new scheme is referred to as the pointer forwarding with distributed HLR (PFDHLR). Since no registration to the HLR is performed in the pointer forwarding scheme when a user moves to the new locations, the cost of updating multiple HLR's is eliminated in PFDHLR. Our study indicates that PFDHLR may significantly reduce the mobility management cost compared with the single HLR approach.
Location tracking with distributed HLR's and pointer forwarding
(1998-02-01)
Lin, YB
;
Tsai, WN
;
資訊工程學系
;
Department of Computer Science
Location tracking operations in a personal communications services (PCS's) network are expensive. A location tracking algorithm called pointer forwarding has been proposed to reduce the location update cost, The key observation behind forwarding is that if users change PCS registration areas (RA's) frequently, but receive calls relatively infrequently, it should be possible to avoid registrations at the home-location register (HLR) database by simply setting up a forwarding pointer from the previous visitor-location register (VLR), Calls to a given user will first query the user's HLR to determine the first VLR, which the user was registered at, and then follow a chain of forwarding pointers to the user's current VLR. To reduce the "find" cost in call delivery, the PCS service provider may distribute HLR databases in the network. This paper integrates the concept of distributed HLR's with pointer forwarding, and the new scheme is referred to as the pointer forwarding with distributed HLR (PFDHLR). Since no registration to the HLR is performed in the pointer forwarding scheme when a user moves to the new locations, the cost of updating multiple HLR's is eliminated in PFDHLR. Our study indicates that PFDHLR may significantly reduce the mobility management cost compared with the single HLR approach.
Performance of CDPD with timed hop and forced hop
(2001)
Chuang, YM
;
Lin, YB
;
Tsai, WN
;
資訊工程學系
;
Department of Computer Science
Cellula, Digital Packet Data (CDPD) offers mobile users access to a low-cost, ubiquitous, wireless data network. CDPD can be overlaid on existing AMPS analog cellular systems and share their infrastructure equipment on a non-interfering basis. To prevent interference with the voice activities, CDPD performs forced hop to a channel stream when a voice request is about to use the RF channel occupied by that channel stream. In addition? several timers and system parameters are defined in CDPD to ensure that the normal AMPS activities are not affected by CDPD. This article investigates how the channel selection algorithms, the timers and other parameters affect the performance of AMPS/CDPD systems. Specifically, we study the trade-off between mean CDPD channel holding time and voice incompletion probability. Our study indicates that if AMPS exercises the most-idle channel selection algorithm and CDPD exercises the least-idle channel selection algorithm, then the largest mean CDPD channel holding time is expected. On the other hand, if AMPS exercises the least-idle channel selection algorithm, then the smallest voice incompletion probability is expected.