Browsing by Author "Liao, Chen-Hung"

Now showing 1 - 5 of 5

An Eavesdropping Prevention Problem When Repairing Network Coded Data from Remote Distributed Storage
(2013-01-01)
Chen, Yu-Jia
;
Liao, Chen-Hung
;
Wang, Li-Chun
;
交大名義發表
;
National Chiao Tung University
We consider the cloud storage systems with data stored in two geographically different datacenters for remote backup. In such system, inter-data center communication is established for data repair when storage nodes fail in the data center. Since the repairing data are transmitted over the Internet, the communication between the datacenters can become susceptible to eavesdropping. This problem is especially crucial in network coding-based distributed storage systems because more repair bandwidth and repair links are required, compared to conventional replication. In this paper, we show that remote repair bandwidth can be reduced by increasing storage per node and derive the tradeoff curves between remote repair bandwidth and storage. Moreover, we show that there exist another tradeoff for storage cost and reliability for different amount of remote and local storage nodes.
Eavesdropping Prevention for Heterogeneous Internet of Things Systems
(2018-01-01)
Liao, Chen-Hung
;
Shuai, Hong-Han
;
Wang, Li-Chun
;
交大名義發表
;
National Chiao Tung University
With the rapid growth of Internet of Things (IoT), the idea of integrating a variety of IoTs has been proposed to support a variety of novel applications. However, IoT devices are often deployed in an open environment in which IoTs are inclined to be malfunctioned. Although data reliability can be achieved by data recovery with conventional replication, the communication between IoTs is susceptible to eavesdropping. Since most of the current work focuses on designing the architectures for IoTs under the specific scenarios, the eavesdropping prevention for heterogeneous IoT systems remains unexplored. Therefore, in this paper, we consider using the network-coding-based distributed storage systems for security and show that repair bandwidth can be reduced by increasing storage per node. Moreover, we theoretically derive the relation between repair bandwidth and storage in heterogeneous IoT systems. Finally, we show the relation between storage cost and reliability with regard to different amounts of IoT devices.
Eavesdropping Prevention for Network Coding Encrypted Cloud Storage Systems
(2016-08)
Chen, Yu-Jia
;
Wang, Li-Chun
;
Liao, Chen-Hung
;
電機學院
;
College of Electrical and Computer Engineering
Network coding is an important cloud storage technique, which can recover data with small repair bandwidth and high reliability compared to the existing erasure coding and replication methods. However, regardless of which data recovery technique is used, the repaired data in a geographically distributed cloud storage system are easy to be eavesdropped at the transmission link between the local datacenter and its remote backup site. This kind of network security issue is called link eavesdropping in this paper. For a network coded cloud storage system, we propose a systematic design methodology to determine the important data recovery system parameters for any specified security level. Through analysis, we present the performance curves to relate the remote repair bandwidth and the number of coded data fragments. Consequently, all the important system parameters of a network coded data recovery system, including the number of storage nodes and the link capacity between the datacenter and the backup site, can be precisely designed for satisfying different security level requirements.
RNN-Assisted Network Coding for Secure Heterogeneous Internet of Things With Unreliable Storage
(2019-10-01)
Liao, Chen-Hung
;
Shuai, Hong-Han
;
Wang, Li-Chun
;
電機工程學系
;
Department of Electrical and Computer Engineering
With the rapid growth of Internet of Things (IoT), integrating a variety of IoT can result in novel applications. However, IoT devices are often deployed in an open environment where IoT are inclined to be malfunctioned. Although data reliability can be achieved by data recovery with conventional replication, the communication between IoT is susceptible to eavesdropping. Therefore, in this paper, we study the eavesdropping prevention of data repair in IoT environments based on network coding. We theoretically derive the relation between security level and storage in heterogeneous IoT systems. To further reduce the repair bandwidth, we exploit recurrent neural network for the storage failure prediction. Under the condition when failure probability and workloads of storage devices are considered, two allocation algorithms are proposed to avoid data repair. Finally, we show the relation between storage cost and reliability with different numbers of IoT devices. Experimental results manifest that the proposed allocation algorithms can outperform the baseline case by 18.4% in terms of the security level.
The integration of synchronous communication technology into service learning for pre-service teachers' online tutoring of middle school students
(2011-01-01)
Chen, Chao-Hsiu
;
Liao, Chen-Hung
;
Chen, Yi-Chieh
;
Lee, Chen-Feng
;
教育研究所
To well prepare pre-service teachers for their future teaching, researchers and teacher-educators have been employing information and communication technology to improve pre-service teachers' learning of subject-matter knowledge, pedagogies, classroom-management skills, and so on. This study illustrates a service-learning project we conducted to engage 18 Taiwanese pre-service teachers in tutoring middle school students by means of synchronous communication tools. To evaluate this project, we collected data from observations, surveys, postings on a discussion forum, teaching journals, and learning journals. Although the pre-service teachers and students generally held positive attitudes toward the tutoring experience and the pre-service teachers reported various benefits from participating in this project, some tutors were concerned with the effectiveness of online tutoring. Most of the tutors tried to motivate their students by providing appealing materials to, and by facilitating interaction with, the students. Yet, some tutors were troubled by students' misbehavior and low motivation. (C) 2010 Elsevier Inc. All rights reserved.