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On Distributed Fault-Tolerant Detection in Wireless Sensor Networks,”
- IEEE Trans. Computers,vol.
, 2006
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1 Decentralized Hypothesis Testing in Wireless Sensor Networks in the Presence of Misbehaving Nodes
"... Abstract—Wireless sensor networks are prone to node misbehavior arising from tampering by an adversary (Byzantine attack), or due to other factors such as node failure resulting from hardware or software degradation. In this paper we consider the problem of decentralized detection in wireless sensor ..."
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Abstract—Wireless sensor networks are prone to node misbehavior arising from tampering by an adversary (Byzantine attack), or due to other factors such as node failure resulting from hardware or software degradation. In this paper we consider the problem of decentralized detection in wireless sensor networks in the presence of one or more classes of misbehaving nodes. Binary hypothesis testing is considered where the honest nodes transmit their binary decisions to the fusion center (FC), while the misbehaving nodes transmit fictitious messages. The goal of the FC is to identify the misbehaving nodes and to detect the state of nature. We identify each class of nodes with an operating point (false alarm and detection probabilities) on the ROC (receiver operating characteristic) curve. Maximum likelihood estimation of the nodes ’ operating points is then formulated and solved using the expectation maximization (EM) algorithm with the nodes ’ identities as latent variables. The solution from the EM algorithm is then used to classify the nodes and to solve the decentralized hypothesis testing problem. Numerical results compared with those from the reputation-based schemes show a significant improvement in both classification of the nodes and hypothesis testing results. We also discuss an inherent ambiguity in the node classification problem which can be resolved if the honest nodes are in majority. Index Terms—Wireless sensor networks, decentralized hypothesis testing, expectation maximization, sensor node classification, Byzantine attack. I.
Scalable PHY-Layer Security for Distributed Detection in Wireless Sensor Networks
"... Abstract—The problem of binary hypothesis testing is considered in a bandwidth-constrained densely populated low-power wireless sensor network operating over insecure links. Observations of the sensors are quantized and encrypted before transmission. The encryption method maps the output of the quan ..."
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Abstract—The problem of binary hypothesis testing is considered in a bandwidth-constrained densely populated low-power wireless sensor network operating over insecure links. Observations of the sensors are quantized and encrypted before transmission. The encryption method maps the output of the quantizer to one of the possible quantizer output levels randomly according to a probability matrix. The intended (ally) fusion center (AFC) is aware of the encryption keys (probabilities) while the unauthorized (third party) fusion center (TPFC) is not. A constrained optimization problem is formulated from the point of view of AFC in order to design its decision rule along with the encryption probabilities. The objective function to be minimized is the error probability of AFC and the constraint is a lower bound on the error probability of TPFC. In the binary case the optimal solution is found and in the nonbinary case a good suboptimal solution is analytically obtained. Numerical results are presented to show that it is possible to degrade the error probability of TPFC significantly and still achieve very low probability of error for AFC. The proposed method which may be considered a PHY-layer security scheme is highly scalable since it does not increase the packet overhead or transmit power of the sensors and has very low computational complexity. A scheme is described to randomize the keys so as to defeat any key space exploration attack. Index Terms—Decentralized detection, decision fusion rule, information security, soft decision, wireless sensor networks. I.
Secure Distributed Detection in Wireless Sensor Networks via Encryption of Sensor Decisions
"... ii Acknowledgements I am delighted to express my sincere gratitude to my major advisor, Dr. Morteza Naraghi-Pour for his exemplary support and guidance for my intellectual progress. He taught me how to approach a problem and inspired me how to be patient in dark times when progress is slow and overc ..."
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ii Acknowledgements I am delighted to express my sincere gratitude to my major advisor, Dr. Morteza Naraghi-Pour for his exemplary support and guidance for my intellectual progress. He taught me how to approach a problem and inspired me how to be patient in dark times when progress is slow and overcome all the hurdles on the way towards my Masters degree. His role as a major professor was not just restricted to technical advice and has been mentoring me in developing social relations in academia. I would like to thank my committee members, Dr. Xue-Bin Liang and Dr. Guoxiang Gu for their kind support. I also deeply appreciate Dr. Shaungqing Wei, Dr. Xue-Bin Liang, Dr. Robert Lipton (Department of Mathematics) and Dr. Hsiao-Chun Wu whom I am associated with in my classroom courses. I also thank Dr. Vaidyanathan and Dr. Richardson (Dept. of Mathematics) for their valuable suggestions in my course-plan. Furthermore, I thank the Dept. of Electrical and Computer Engineering for supporting me financially from my first day in LSU, making me concentrate on my research without any deviations. My deepest gratitude goes to my parents for moulding me as who I am. They patted my back whenever I made a right decision and protected me from the consequences of my wrong decisions. I would also like to thank all my relatives and friends for giving me a wonderful experience during my stay here in LSU. They boosted me with all the energy I need to pursue research, esp. when I was dull and gloomy. This certainly will prove to be a great starting point for me in my research...
Cooperation Reliability based on Reinforcement Learning for Cognitive Radio Networks
"... Abstract —The primary objective of cooperation in Cognitive Radio (CR) networks is to increase the efficiency and improve the network performance. However, CR users may act destructively and decrease both their own and others ’ performances. This can be due to Byzantine adversaries or unintentional ..."
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Abstract —The primary objective of cooperation in Cognitive Radio (CR) networks is to increase the efficiency and improve the network performance. However, CR users may act destructively and decrease both their own and others ’ performances. This can be due to Byzantine adversaries or unintentional erroneous conduct in cooperation. This work presents an autonomous cooperation solution for each CR user, i.e., each CR user decides with whom to cooperate. The objective of the proposed solution is to increase the spectrum access in cooperative CR networks. To realize this, a Reinforcement Learning (RL) algorithm is utilized to determine the suitability of the available cooperators and select the appropriate set of cooperators. In addition, the proposed solution determines the most appropriate number of cooperators to achieve the highest efficiency for spectrum access. Accordingly, the control communication overhead is reduced. The simulation results demonstrate the learning capabilities of the proposed to achieve reliable behavior under highly unreliable conditions. Keywords- cognitive radio networks, cooperation, reinforcement learning, reliability. I.
DISTRIBUTED FAULT-TOLERANT EVENT DETECTION FOR NON-SYMMETRIC ERRORS IN WIRELESS SENSOR NETWORKS
"... Abstract Wireless sensor network (WSN) ..."
Design Space . . . in Modern Embedded Systems
"... Power minimization is a critical challenge for modern embedded system design. Recently, due to the rapid increase of system’s complexity and the power density, there is a growing need for power control techniques at various design levels. Mean-while, due to technology scaling, leakage power has beco ..."
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Power minimization is a critical challenge for modern embedded system design. Recently, due to the rapid increase of system’s complexity and the power density, there is a growing need for power control techniques at various design levels. Mean-while, due to technology scaling, leakage power has become a significant part of power dissipation in the CMOS circuits and new techniques are needed to reduce leakage power. As a result, many new power minimization techniques have been proposed such as voltage island, gate sizing, multiple supply and threshold voltage, power gating and input vector control, etc. These design options further enlarge the design space and make it prohibitively expensive to explore for the most energy efficient design solution. Consequently, heuristic algorithms and randomized algorithms are frequently used to explore the design space, seeking sub-optimal solutions to meet the time-to-market requirements. These algorithms are based on the idea of truncating the design space and restricting the search in a subset of the original design space. While this approach can effectively reduce the runtime of searching, it may also
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"... I would like to express my gratitude to my advisor, Dr. Morteza Naraghi Pour for his guidance and motivation towards the completion of this thesis. His technical advice and suggestions helped me overcome hurdles and kept me enthusiastic and made this a wonderful learning experience. I would like to ..."
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I would like to express my gratitude to my advisor, Dr. Morteza Naraghi Pour for his guidance and motivation towards the completion of this thesis. His technical advice and suggestions helped me overcome hurdles and kept me enthusiastic and made this a wonderful learning experience. I would like to thank him for being very supportive and patient with me during my thesis and write up. I have learned a lot from him which will help me in my academic and professional career. I would like to thank my committee members Dr. Jorge Aravena and Dr. Xue-Bin Liang for taking time out of their busy schedule and agreeing to be a part of my committee. I would like to thank all my friends at LSU who made my stay at LSU pleasant and enjoyable. I would like to thank Chetan Chitnis for helping me with my write up. Finally, I would like to thank my parents and sister for the support and unconditional love they provided me throughout my life. They have supported me in every decision I made in my life. I hope the completion of my degree will be a stepping
OPTIMAL FAULT-TOLERANT EVENT DETECTION IN WIRELESS SENSOR NETWORKS
"... In this paper, we propose an optimal fault-tolerant algorithm for distributed event detection in wireless sensor networks. Two important problems are addressed: 1. How to handle both the noise-related measurement error and sensor fault simultaneously in fault-tolerant detection? 2. How to choose a p ..."
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In this paper, we propose an optimal fault-tolerant algorithm for distributed event detection in wireless sensor networks. Two important problems are addressed: 1. How to handle both the noise-related measurement error and sensor fault simultaneously in fault-tolerant detection? 2. How to choose a proper neighborhood size n for a sensor node in fault correction such that the maximum energy could be conserved? Both theoretical analysis and experimental results confirm the effectiveness and efficiency of the proposed algorithm. 1.
Energy-Driven Detection Scheme with Guaranteed Accuracy
"... Abstract — This is our first step towards a holistic investigation of the minimum energy for wireless sensor network (WSN) to perform a specific function. We consider wireless sensor networks that perform an event detection function. Each sensor node will repetitively collect a 1-bit information reg ..."
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Abstract — This is our first step towards a holistic investigation of the minimum energy for wireless sensor network (WSN) to perform a specific function. We consider wireless sensor networks that perform an event detection function. Each sensor node will repetitively collect a 1-bit information regarding whether the event occurs or not in its neighborhood. A fusion center will make the decision on whether the event occurs based on the information provided by individual sensor nodes. Traditionally, a centralized scheme requires each sensor node to forward all its observations to the fusion center, which results in large energy in communication. A distributed scheme, on the other hand, allows each sensor node to make its own decision and then send out only its 1-bit decision. This reduces communication energy at the cost of increased processing energy and reduced detection accuracy. We propose a hybrid energy-driven scheme where each sensor node sends out its 1-bit decision if that decision exceeds a predetermined detection accuracy threshold, and sends out all its observations otherwise. This scheme provides WSN designers the flexibility to balance detection accuracy, sensor density, and energy consumption. We develop the optimal decision rules for this scheme. We also propose methods to calculate the detection accuracy threshold for individual sensor node to guarantee the overall detection accuracy at the fusion center. The simulation results show that the hybrid scheme consumes significantly less energy than both centralized and distributed schemes to achieve the same detection accuracy. I.