Browsing by Author "Wang, Shu-Ching"

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Byzantine Agreement & Fault Diagnosis Agreement in Dynamic Ad-Hoc Environment
(2008)
Cheng, Chien-Fu
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Wang, Shu-Ching
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Liang, Tyne
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資訊工程學系
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Department of Computer Science
Since wireless communication and mobile computing are becoming more and more ubiquitous, the reliability and fault tolerance of the Mobile Ad-hoc Network (MANET) has become an important topic. In order to provide a reliable environment, a mechanism that allows a set of nodes to reach a common agreement, even in the presence of faulty nodes, is needed. Therefore, the Byzantine Agreement (BA) problem has drawn attention of more researchers. Traditionally, the BA problem was focused on wired networks. We know that the physical topology of a wired network is static, but the physical topology of an MANET is dynamic. Thus, previous BA protocols are not applicable in an MANET. In this paper, a new protocol is proposed to solve the BA problem with malicious faulty components in dynamic MANET. Furthermore, we also propose a new Fault Diagnosis Agreement (FDA) protocol to detect/locate faulty components to provide a highly reliable environment. From the performance perspective, the proposed protocols use the minimum number of message exchanges and can tolerate/detect/locate the maximum number of faulty nodes allowed in the dynamic network.
FILE CONSISTENCY PROBLEM OF FILE-SHARING IN PEER-TO-PEER ENVIRONMENT
(2010-02-01)
Cheng, Chien-Fu
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Wang, Shu-Ching
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Liang, Tyne
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資訊工程學系
;
Department of Computer Science
In this paper, file consistency problem of file-sharing with malicious processors in Peer-to-Peer (P2P) networks is investigated. We propose a novel hybrid approach integrating the clustering algorithm and consensus protocol to provide better Quality of Service (QoS) and solve the file consistency problem in the P2P file-sharing system. First, the clustering algorithm is introduced in our approach to provide better QoS. After clustering, we use consistent hash Junction to assign each processor and key to the corresponding processor in the de-Bruijn network. The de-Bruijn graph is nearly optimal and feature very short average routing distances. Finally, We use the consensus protocol to reach the consistent file information.
Investigation of Consensus Problem over Combined Wired/Wireless Network
(2009-07-01)
Cheng, Chien-Fu
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Wang, Shu-Ching
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Liang, Tyne
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資訊工程學系
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Department of Computer Science
Wireless networks have become ubiquitous, making combined wired/wireless network a popular trend of development in nowadays, Therefore, the Consensus problem in combined wired/wireless network is an important topic. Over the past few years, a considerable number of studies have been made on pure wired networks. However, no studies have ever tried to solve the Consensus problem in combined wired/wireless networks. In order to meet the characteristics of combine wired/wireless networks (the limited resources have made the computation ability of mobile processors often weaker than that of stationary processors) and reduce the number of rounds of message exchange required, most of the communications and computation overhead must be fulfilled within by the consensus-servers. Therefore, we introduce a hierarchical concept in our system model. Only consensus-servers need to exchange messages and compute the common value. In this paper, we will investigate the Consensus problem in combined wired/wireless network to enhance fault-tolerance and reliability. Besides, we also prove our protocol is able to tolerate a maximum number of allowable faulty components with minimum rounds of message exchange required.
The anatomy study of server-initial agreement for general hierarchy wired/wireless networks
(2009-01-01)
Cheng, Chien-Fu
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Wang, Shu-Ching
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Liang, Tyne
;
資訊工程學系
;
Department of Computer Science
The Byzantine Agreement (BA) plays a key role in fault-tolerant distributed system design. A number of solutions to the BA problem based on Various network model assumptions have been proposed. However, most existing BA protocols are designed for pure wired or pure wireless networks, In practice, most current networks are combined wired and wireless environments. In this paper, we extend the BA problem over a combined wired/wireless network, consisting of both powerful computing stationary processor and low-power mobile processor. The communication overhead of BA protocol is inherently large and secure group communications are important. The protocols proposed in this paper use the hierarchical model concept to reduce the communication overhead and provide secure group communications well suited for combined wired/wireless networks. (C) 2007 Elsevier B.V. All rights reserved.
Zone-oriented Byzantine Agreement on zone-based wireless ad-hoc network
(2006)
Cheng, Chien-Fu
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Wang, Shu-Ching
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Liang, Tyne
;
資訊工程學系
;
Department of Computer Science
A wireless ad-hoc network system may suffer from various types of hardware failure. In order to enhance the fault-tolerance and reliability of the wireless ad-hoc networks, we revisit the Byzantine Agreement problem in the zone-based wireless ad-hoc network in this paper. The proposed protocol is called as the Zone-Oriented Agreement Protocol (ZOAP) which can make each fault-free mobile processor reach an agreement value to cope with the faulty component in the zone-based wireless ad-hoc network.