Browsing by Author "Jan, Rong-Hong"

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A bilateral remote user authentication scheme that preserves user anonymity
(2008-07-01)
Tseng, Huei-Ru
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
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Department of Computer Science
Smart card-based authentication is one of the most widely used and practical solutions to remote user authentication. Compared to other authentication schemes, our proposed scheme aims to provide more functionalities and to resist well-known attacks. These crucial merits include (1) a user can freely choose and change his passwords; (2) our scheme provides mutual authentication between a server and a user; (3) it achieves user anonymity; (4) a server and a user can generate authenticated sessions keys. Moreover, our scheme can resist replay attacks, forgery attacks, insider attacks, reflection attacks, and parallel session attacks. Copyright (c) 2008 John Wiley & Sons, Ltd.
A Chaotic Maps-based Key Agreement Protocol that Preserves User Anonymity
(2009)
Tseng, Huei-Ru
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
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Department of Computer Science
A key agreement protocol is a protocol whereby two or more communicating parties can agree on a key or exchange information over an open communication network in such a way that both of them agree on the established session keys for use in subsequent communications. Recently, several key agreement protocols based on chaotic maps are proposed. These protocols require a verification table to verify the legitimacy of a user. Since this approach clearly incurs the risk of tampering and the cost of managing the table and suffers from the stolen-verifier attack, we propose a novel key agreement protocol based on chaotic maps to enhance the security. The proposed protocol not only achieves mutual authentication without verification tables, but also allows users to anonymously interact with the server. Moreover, security of the proposed protocol is modelled and analyzed with Petri nets. Our analysis shows that the proposed protocol can successfully defend replay attacks, forgery attacks, and stolen-verifier attacks.
A factoring approach for the Steiner tree problem in undirected networks
(2007-06-15)
Wang, Chu-Fu
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
In communication networks, many applications, such as video on demand and video conferencing, must establish a communications tree that spans a subset K in a vertex set. The source node can then send identical data to all nodes in set K along this tree. This kind of communication is known as multicast communication. A network optimization problem, called the Steiner tree problem (STP), is presented to find a least cost multicasting tree. In this paper, an O(vertical bar E vertical bar) algorithm is presented to find a minimum Steiner tree for series-parallel graphs where vertical bar E vertical bar is the number of edges. Based on this algorithm, we proposed an O(2(2c) . vertical bar E vertical bar) algorithm to solve the Steiner tree problem for general graphs where c is the number of applied factoring procedures. The c value is strongly related to the topology of a given graph. This is quite different from other algorithms with exponential time complexities in vertical bar K vertical bar. (c) 2007 Elsevier Inc. All rights reserved.
A fast failure detection and failover scheme for SIP high availability networks
(2007)
Wu, Wei-Ming
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Wang, Kuochen
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Jan, Rong-Hong
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Huang, Chia-Yuan
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資訊工程學系
The SIP proxy server, which is an important building block of a SIP network, can be in a form of a cluster to prevent service unavailability caused by software or hardware failures. The design of a SIP proxy server cluster with a single dispatcher in a SIP network faces the single-point-of-failure problem. The use of dual SIP dispatcher architecture was proposed and VRRP (Virtual Router Redundancy Protocol) was used as an JP failover mechanism. In this paper, we have designed and implemented a dependable SIP network that includes n + k SIP dispatchers (n active dispatchers + k backup dispatchers) to control and monitor a cluster of m SIP proxy servers for VoIP and video conferencing applications. A fast failure detection and failover (FFF) scheme has also been proposed. FFF uses OpenAIS as a high availability middleware to perform health check and failover of dispatchers and proxy servers. Experimental results have shown that the FFF scheme reduces the dispatcher failover time by 80% compared to the VRRP mechanism and also shorten the proxy failover time by 85% compared to the mechanism provided by OpenSER itself
A Fast Window-based Scalar Multiplication Algorithm for Elliptic Curve Cryptography in Wireless Sensor Networks
(2015-01-01)
Ye, Hung-Nan
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Wang, Kuochen
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Jan, Rong-Hong
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Hu, Yuh-Jyh
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Tseng, Yu-Chee
In this paper, we propose an enhanced window-based mutual opposite form (EW-MOF) for scalar multiplication with ECC in WSNs. The proposed EW-MOF combines MOF with an enhanced window method that can reduce not only pre-computation time and memory usage, but also average key generation time that includes pre-computation time in each sensor node. Our analysis has shown that the proposed EW-MOF requires a smaller number of essential pre-computed points than the one's complement. Therefore, it is very suitable for WSNs. Simulation results show that the proposed EW-MOF is 24.69% faster than the one's complement method, which is the best method available, in the average key generation time of ECC that includes pre-computation time under different field sizes. In summary, the proposed EW-MOF is more feasible than the one's complement for wireless sensor networks in terms of key generation time and power saving.
A GPS-less, outdoor, self-positioning method for wireless sensor networks
(2007-07-01)
Chu, Hung-Chi
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
One challenging issue in sensor networks is to determine where a given sensor node is physically located. This problem is especially crucial for very small sensor nodes. This paper presents a GPS-less, outdoor, self-positioning method for wireless sensor networks. In our method, a set of nodes, called reference points (RPs), are deployed in the sensor network with overlapping regions of coverage. The RP periodically broadcasts beacon frames which contain localization data. The sensor node collects the beacon frames from RPs and process the data in the frame; it can then easily localize itself. The analysis of positioning accuracy is given to show how well a sensor node can correctly localize itself. In the optimal transmitting power, the worst-case accuracy for all data points is within 28.87% of the separation-distance between two adjacent RPs and the average accuracy is within 15.51%. The simulation results also show the robustness of the proposed method. Finally, we have implemented our positioning method on a sensor network test bed and the actual measurement show that the method can achieve average accuracy within 17.9% of the separation-distance between two adjacent RPs in an outdoor environment. (C) 2006 Elsevier B.V. All rights reserved.
A MAC protocol for multi-channel multi-interface wireless mesh network using hybrid channel assignment scheme
(2007-07-01)
Li, Chi-Yu
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Jeng, An-Kai
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
In recent years, Wireless Mesh Network (WMN) which uses a multi-hop configuration to extend the reach of the last-mile access to Internet has come into public notice. WMN improves network performance by the use of multiple orthogonal (non-overlapping) channels and multiple wireless interfaces. However, the Medium Access Control (MAC) protocol in IEEE 802.11 standard was designed and suited for only one channel and one interface. In this paper, we present a new MAC protocol which is specially designed for multi-channel and multi-interface WMNs. The proposed MAC protocol employs a hybrid channel assignment strategy to solve the rendezvous problem and a waiting time scheme for updating network allocation vectors (NAVs) to solve the multi-channel hidden terminal problem. Simulation results show that the proposed protocol can achieve a better utilization of both interfaces and channels.
A multiple power-level approach for wireless sensor network positioning
(2008-11-13)
Fang, Jen-Yu
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Chu, Hung-Chi
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
Wireless sensor networks enhance our ability to monitor the physical world. Many recent researches on wireless sensor networks have focused on aspects such as routing, node cooperation, and energy consumption. In addition to these topics, the positioning service is also an important function in sensor networks. This paper presents a multiple power-level positioning algorithm, discusses its capabilities, and evaluates its performance in various environments. The simulation results show that the proposed algorithm exhibits better accuracy than do traditional single power-level methods. In critical situations such as reference node failure, unstable radio transmission range and beacon collision, the proposed algorithm still performs well. Finally, the positioning method is implemented on a sensor network test bed, and the actual measurements show that, the average estimation error is 2.5 m when three power-levels are used and adjacent reference nodes are 12 m apart in an outdoor environment. (C) 2008 Elsevier B.V. All rights reserved.
A power-saving scheduling for infrastructure-mode 802.11 wireless LANs
(2006-11-08)
Lin, Hsiao-Po
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Huang, Shih-Chang
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
This paper presents a novel method to arrange wakeup schedule for sleeping stations such that the number of wakeup stations in each beacon interval is balanced in IEEE 802.11 wireless local area networks (WLANs). This method reduces the probability of collision and thus the station can save more power. Next, we consider how to poll the wakeup stations to send the PS-Poll frame to get back their buffered data so that the contention can be avoided. Three different access scheduling mechanisms are proposed for the contention avoidance. In the first mechanism, only one of wakeup stations is scheduled to access the buffered data. The second and third mechanisms based on the smallest association ID (AID) first and the smallest queue length first, respectively, arrange a subset of wakeup stations to get back their buffered data within a beacon interval. Simulation results show that the proposed methods are effective in the power-saving. (c) 2006 Elsevier B.V. All rights reserved.
A robust user authentication scheme with self-certificates for wireless sensor networks
(2011-08-01)
Tseng, Huei-Ru
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
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Department of Computer Science
User authentication is a critical part of security, along with confidentiality and integrity, for computer systems that allow legitimate users remote access over an open communication network. Recently, user authentication for wireless sensor networks (WSNs) has received considerable attention. We propose a robust user authentication scheme for WSNs. The scheme is based on elliptic-curve cryptosystems with self-certificates. The proposed scheme allows users to change their key pairs without interaction with a key distribution center (KDC). Moreover, the proposed scheme still works well even if the adversary captures t nodes out of n nodes in the WSNs. Security of the proposed scheme is modeled and analyzed with Petri nets. Our analysis shows that the proposed scheme can successfully defend some of the most notorious attacks, including replay attacks, forgery attacks, and node-capture attacks. Copyright (C) 2010 John Wiley & Sons, Ltd.
Adaptive Topology Control for Mobile Ad Hoc Networks
(2011-12-01)
Jeng, Andy An-Kai
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
In MANETs, mobile devices are usually powered by batteries with limited energy supplies. Topology control is a promising approach, which conserves energy by either reducing transmission power for each node or preserving energy-efficient routes for the entire network. However, there is empirically a trade-off between the energy efficiency of the nodes and routes in a topology. Besides, it may consume considerable energy to maintain the topology due to node mobility. In this paper, we propose an adaptive topology control protocol for mobile nodes. The protocol allows each node to decide whether to support energy-efficient routing or conserve its own energy. Moreover, it can drastically shrink the broadcasting power of beacon messages for mobile nodes. We prove that any reconstruction and change of broadcasting radius converge in four and five beacon intervals, respectively. The experimental results show that our protocol can significantly reduce the total energy consumption for each successfully transmitted packet, and prolong the life times of nodes, especially in high mobility environments.
Adaptive Urban Traffic Signal Control System with Bus Priority
(2013-01-01)
Jeng, Andy An-Kai
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Jan, Rong-Hong
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Chen, Chien
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Chang, Tzu-Lin
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資訊工程學系
In recent years, with the economic development and urbanization, traffic congestion has become a serious problem in urban environments. Traffic signal control plays a key role in Intelligent Transportation System (ITS). Particularly, bus system can carry a higher capacity of passengers, which help to relief traffic jam in cities. However, different from ordinary vehicles, bus system has several unique features, including higher capacity of passengers, fixed routes and specific requirements on arrival time and headway. In this paper, we propose an adaptive traffic signal control approach with bus Priority that determines the phase sequence and time in non-fixed order based on synergic information to improve the performance of bus system with a very small cost to ordinary vehicles. Simulation results show that our approach can significantly reduce the waiting time of buses, keep bus schedules on time, and regular bus headway.
An adaptive topology control scheme for energy-efficient routing in mobile ad hoc networks
(2007)
Jeng, Andy An-Kai
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
In mobile ad hoc networks, nodes are usually powered by batteries with limited energy. To prolong the network life, the energy consumption of the routing task is crucial. In previous works, enormous topology control methods were given to support the energy-efficient routing, while the most of them are designed for static network. In this paper, we proposed a novel topology control scheme for mobile nodes. It is based on an adjustable structure, named the r-neighborhood graph. Simulation results show the proposed scheme can significantly improve the energy consumption especially in high mobility environment.
An efficient relay sensors placing algorithm for connectivity in wireless sensor networks
(2006)
Chang, Jyh-Huei
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Jan, Rong-Hong
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資訊工程學系
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Department of Computer Science
Randomly deployed sensor networks often make initial communication gaps inside the deployed area even in an extremely high-density network. How to add relay sensors such that the underlying graph is connected and the number of relay sensors added is minimized is an important problem in wireless sensor networks. This paper presents an Efficient Relay Sensors Placing Algorithm (ERSPA) for solving such a problem. Compared with minimum spanning tree algorithm and greedy algorithm, ERSPA achieves a better performance in terms of number of relay sensors added. Simulation results show that the average number of relay sensors added by minimal spanning tree algorithm is approximately up to two times than ERSPA algorithm.
An Energy-Efficient Scheduling for Multiple MSSs in IEEE 802.16e Broadband Wireless
(2008)
Huang, Shih-Chang
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Chen, Chien
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Jan, Rong-Hong
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Hsieh, Cheng-Chung
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資訊工程學系
This paper proposes an energy-efficient traffic scheduling approach for 802.16e broadband wireless networks. Instead of considering a single Mobile Subscriber Station (MSS) as most of the current researchers do, multiple MSSs are considered in our work. The constant bit rate traffic with QoS delay constraint is considered in this paper. The proposed approach considers both energy efficiency and bandwidth utilization. First, we derive a minimum wakeup time for each MSS to achieve the maximum power saving by waking up the minimum number of time slots. After then, we interleave the traffic of multiple MSSs by taking advantage of feasible slot allocation. In order to support the maximum number of MSSs, our scheduling problem can be transformed into a maximum bipartite matching problem. We use the Ford-Fulkerson maximum flow algorithm to obtain a feasible schedule for multiple MSSs. Simulation results show that our proposed approach has better bandwidth utilization and achieves maximum energy saving.
An improved dynamic user authentication scheme for wireless sensor networks
(2007)
Tseng, Huei-Ru
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Jan, Rong-Hong
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Yang, Wuu
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資訊工程學系
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Department of Computer Science
Over the last few years, many researchers have paid a lot of attention to the user authentication problem. However, to date, there has been relatively little research suited for wireless sensor networks. Recently, Wong et al. proposed a dynamic user authentication scheme for WSNs that allows legitimate users to query sensor data at every sensor node of the network. We show that Wong et al.'s scheme is vulnerable to the replay and forgery attacks and propose a lightweight dynamic user authentication scheme for WSNs. The proposed scheme not only retains all the advantages in Wong et al.'s scheme but also enhances its security by withstanding the security weaknesses and allows legitimate users to change their passwords freely. In comparison with the previous scheme, our proposed scheme possesses many advantages, including resistance of the replay and forgery attacks, reduction of user's password leakage risk, capability of changeable password, and better efficiency.
An Upper Bound of the Throughput for Multi-Radio Wireless Mesh Networks
(2010-08-01)
Jan, Rong-Hong
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Huang, Shu-Ying
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Wang, Chu-Fu
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資訊工程學系
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Department of Computer Science
This paper focuses on how to determine an upper bound of maximum throughput from mesh clients to the Internet (or from the Internet to mesh clients) for multi-radio Wireless Mesh Networks (WMNs) under an interference-free assumption. In the case of the number of channels for assignment being high enough in a multi-radio WMN to meet the interference-free assumption, then the resulting solution can provide the basis for channel assignment and routing to achieve optimal throughput.
Broadcasting with the least energy is an NP-complete problem
(2008)
Yang, Wuu
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Tseng, Huei-Ru
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Jan, Rong-Hong
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Shen, Bor-Yeh
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交大名義發表
Energy conservation is an important issue in wireless networks. We propose a method for estimating the least amount of energy needed for broadcasting a message to all nodes in the network, The method can work with any reasonable energy models. We prove that this least-energy problem is NP-complete by showing that the maximum-leaf spanning-tree problem is a special case of the least-energy problem.
DDoS detection and traceback with decision tree and grey relational analysis
(2011)
Wu, Yi-Chi
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Tseng, Huei-Ru
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Yang, Wuu
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Jan, Rong-Hong
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資訊工程學系
In Distributed Denial-of-Service (DDoS) Attack, an attacker breaks into many innocent computers (called zombies). Then, the attacker sends a large number of packets from zombies to a server, to prevent the server from conducting normal business operations. We design a DDoS-detection system based on a decision-tree technique and, after detecting an attack, to trace back to the attacker's locations with a traffic-flow pattern-matching technique. Our system could detect DDoS attacks with the false positive ratio about 1.2-2.4%, false negative ratio about 2-10%, and find the attack paths in traceback with the false negative rate 8-12% and false positive rate 12-14%.
DDoS Detection and Traceback with Decision Tree and Grey Relational Analysis
(2009)
Wu, Yi-Chi
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Tseng, Huei-Ru
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Yang, Wuu
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Jan, Rong-Hong
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資訊工程學系
As modern life becomes increasingly closely bound to the Internet, network security becomes increasingly important. Like it or not, we all live under the shadow of network threats. The threats could cause leakage of privacy and/or economic loss. Among network attacks, the DDoS (distributed denial-of-service) attack is one of the most frequent and serious. In a DDoS attack, an attacker first breaks into many innocent computers (called zombies) by taking advantages of known or unknown bugs and vulnerabilities in the software. Then the attacker sends a large number of packets from these already-captured zombies to a server These packets either occupy a major portion of the server's network bandwidth or they consume much of the server's time. The server is then prevented from conducting normal business operations. In order to mitigate the DDoS threat, we design a system to detect DDoS attacks based on a decision-tree technique and, after detecting an attack, to trace back to the approximate locations of the attacker with a traffic-flow pattern-matching technique. We conduct our experiment on the DETER system. According to our experiment results, our system could detect the DDoS attack with the false positive ratio about 1.2% - 2.4%, false negative ratio about 2% - 10% with different kind of attack, attack sending rate and find the attack path in traceback with the false negative rate 8% - 12% and false positive rate 12% - 14%.(1)