Browsing by Author "Shen, Hung-Yen"

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A Fuzzy Logic-Based Routing for Delay-Tolerant Heterogeneous Networks
(2009)
Huang, Chenn-Jung
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Shen, Hung-Yen
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Liao, Jia-Jian
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Hu, Kai-Wen
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Yang, Dian-Xiu
Delay Tolerant Network (DTN) is an intermittently connected mobile wireless network in which the connectivity between nodes changes frequently due to nodes\' movement. Recently, there have been a lot of researches working on this area. However, to the best of our knowledge, no work has addressed on the DTN routing which focuses on the heterogeneous network environment in the literature. In this work, we propose a prediction based routing protocol for the heterogeneous delay tolerant networks wherein edge servers are distributed over the borders of the different network domains. A location prediction algorithm based on the user online logs to intelligently estimate the most possible future location of the destination, if the destination is currently unavailable. Then an edge server selection algorithm based on fuzzy logic system is exploited to select the close-by intermediate node on the path to the destination so that the messages can be saved temporarily for the destination after the location of the destination is predicted. The experimental results exhibit that the proposed routing protocol can efficiently deliver the message under limited buffer space, comparing with two representative delay tolerant network routing protocols in the literature. The scalability of the proposed work is also confirmed in the simulations.
An adaptive bandwidth reservation scheme for 4G cellular networks using flexible 2-tier cell structure
(2010-09-01)
Huang, Chenn-Jung
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Shen, Hung-Yen
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Chuang, Yi-Ta
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資訊工程學系
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Department of Computer Science
Many mechanisms based on bandwidth reservation have been proposed in the literature to decrease connection dropping probability for handoffs in cellular communications. The handoff events occur at a much higher rate in packet-switched fourth generation mobile communication networks than in traditional cellular systems. An efficient bandwidth reservation mechanism for the neighboring cells is therefore critical in the process of handoff during the connection of multimedia calls to avoid the unwillingly forced termination and waste of limited bandwidth in fourth generation mobile communication networks, particularly when the handoff traffic is heavy. In this paper, an adaptive two-tier scheme, which employs grey prediction theory and swarm intelligence techniques, is proposed to reduce the forced termination probability of multimedia handoffs. The simulation results show that the proposed scheme can achieve superior performance than the representative bandwidth-reserving schemes in the literature when performance metrics are measured in terms of the forced termination probability for the handoffs, the call blocking probability for the new connections and bandwidth utilization. (C) 2010 Elsevier Ltd. All rights reserved.
Using Learning Style-Based Diagnosis Tool to Enhance Collaborative Learning in an Undergraduate Engineering Curriculum
(2011-12-01)
Huang, Chenn-Jung
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Liao, Jia-Jian
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Shen, Hung-Yen
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Aye, Nwe Ni
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Wang, Yu-Wu
In this study, an intelligent learning style aware diagnosis agent for computer-supported cooperative learning is proposed. Learners are first assigned to heterogeneous groups based on their learning styles questionnaire given right before the beginning of learning activities on the e-learning platform. The proposed diagnosis agent then scrutinizes each learner's learning portfolio on e-learning platform and automatically issues feedback messages in case some learner's behavior that is unfitted to his/her learning styles or devious argument on discussion board or wiki is detected. The Moodle, an open-source software e-learning platform, is used to establish the cooperative learning environment for this study. The experimental results reveal that the proposed learning style aware diagnosis agent indeed boosts the performance of the learners. (C) 2009 Wiley Periodicals, Inc. Comput Appl Eng Educ 19: 739-746, 2011; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.20359