To address the problem of unsupervised outlier detection in wireless sensor networks, we develop an algorithm that (1) is flexible with respect to the outlier definition, (2) works in-network with a communication load...
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To address the problem of unsupervised outlier detection in wireless sensor networks, we develop an algorithm that (1) is flexible with respect to the outlier definition, (2) works in-network with a communication load proportional to the outcome, and (3) reveals its outcome to all sensors. We examine the algorithm’s performance using simulation with real sensor data streams. Our results demonstrate that the algorithm is accurate and imposes a reasonable communication load and level of power consumption.
This paper proposes a concurrency model which integrates the asynchronous and event-driven nature of networked sensors with a more familiar programming style for the developer. We argue that coroutines can provide a b...
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This paper proposes a concurrency model which integrates the asynchronous and event-driven nature of networked sensors with a more familiar programming style for the developer. We argue that coroutines can provide a basis for this integration and describe some details of its implementation, which was developed as an extension to the TinyOS operating system.
sensor replacement is important for sensor networks to provide continuous sensing services. Existing approaches relocate redundant nodes to fill the holes created by failed sensors and require all or most sensor nodes...
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sensor replacement is important for sensor networks to provide continuous sensing services. Existing approaches relocate redundant nodes to fill the holes created by failed sensors and require all or most sensor nodes to have mobility. However, mobility equipment is expensive while technology trends are scaling sensors to be smaller and cheaper. In this paper, we propose to use a small number of mobile robots to replace failed sensors in a large-scale static sensor network. We study algorithms for detecting and reporting sensor failures and coordinating the movement of robots that minimize the motion energy of mobile robots and the messaging overhead incurred to the sensor network. A manager receives failure reports and determines which robot to handle a failure. We study three algorithms: a centralized manager algorithm, a fixed distributed manager algorithm, and a dynamic distributed manager algorithm. Our simulations show that: (a) The centralized and the dynamic distributed algorithms have lower motion overhead than the fixed distributed algorithm. (b) The centralized algorithm is less scalable than the two distributed manager algorithms. (c) The two distributed algorithms have higher messaging cost than the centralized algorithm. Hence, the optimal choice of the coordination algorithm depends on the specific scenarios and objectives being optimized.
In this paper, we study distributed approximation algorithms for fault-tolerant clustering in wireless ad hoc and sensor networks. A k-fold dominating set of a graph G = (V,E) is a subset S of V such that every node v...
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In this paper, we study distributed approximation algorithms for fault-tolerant clustering in wireless ad hoc and sensor networks. A k-fold dominating set of a graph G = (V,E) is a subset S of V such that every node v \in V \ S has at least k neighbors in S. We study the problem in two network models. In general graphs, for arbitrary parameter t, we propose a distributed algorithm that runs in time O(t^2) and achieves an approximation ratio of O(t\delta^2/t log\delta), where n and \delta denote the number of nodes in the network and the maximal degree, respectively. When the network is modeled as a unit disk graph, we give a probabilistic algorithm that runs in time O(log log n) and achieves an O(1) approximation in expectation. Both algorithms require only small messages of size O(log n) bits.
A wireless sensor network (WSN) is composed of wireless sensors using batteries with energy constraints, which limits the network lifetime. How to maximize the network lifetime is an important issue in the design of W...
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A wireless sensor network (WSN) is composed of wireless sensors using batteries with energy constraints, which limits the network lifetime. How to maximize the network lifetime is an important issue in the design of WSNs. We establish a relationship between node density and network lifetime in a periodically data delivery scenario of WSNs with sensors transmitting data to the sink node periodically. Based on our analysis, we propose a sensor node density deployment method that could implement a differential node density in WSNs so that the lifetime of the network could be maximized. Both theoretic analysis and simulation results show that our method outperforms the uniform node distribution method in terms of the network lifetime
sensor network security solutions that have been proposed so far are mostly built on the assumption of a trusted environment, which is not very realistic so we need trust management before deploying any other security...
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sensor network security solutions that have been proposed so far are mostly built on the assumption of a trusted environment, which is not very realistic so we need trust management before deploying any other security solution. Traditional trust management schemes that have been developed for wired and wireless ad-hoc networks are not suitable for wireless sensor networks because of higher consumption of resources such as memory and power. In this paper, we propose a novel lightweight group based trust management scheme (GTMS) for distributed wireless sensor networks in which the whole group will get a single trust value. Instead of using completely centralized or distributed trust management schemes, GTMS uses hybrid trust management approach that helps in keeping minimum resource utilization at the sensor nodes
We present the design and implementation of POS, an in-network service that computes accurate order statistics energy-efficiently. POS returns a stream of periodic samples from any order statistic. It initially comput...
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We present the design and implementation of POS, an in-network service that computes accurate order statistics energy-efficiently. POS returns a stream of periodic samples from any order statistic. It initially computes the value of the order statistic and then periodically runs a validation protocol to determine whether the value is still valid. If not, it uses an optimized binary search to determine the new value and then resumes periodic validation. POS uses in-network aggregation and transmission suppression to reduce communication complexity. Results from both experiments on a mote testbed and simulations show that POS can compute order statistics accurately while consuming less energy than the best techniques to compute averages in common cases.
Existing network reprogramming protocols target the efficient, reliable, multi-hop dissemination of application updates in sensor networks, but assume correct or fail-stop behavior from participating sensors. Compromi...
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Existing network reprogramming protocols target the efficient, reliable, multi-hop dissemination of application updates in sensor networks, but assume correct or fail-stop behavior from participating sensors. Compromised nodes can subvert such protocols to result in the propagation and remote installation of malicious code. Sluice aims for the progressive, resource-sensitive verification of updates in sensor networks to ensure that malicious updates are not disseminated or installed, while trusted updates continue to be efficiently disseminated. Our verification mechanism provides authenticity and integrity through a hash-chain construction that amortizes the cost of a single digital signature over an entire update. We integrate Sluice with an existing network reprogramming protocol and empirically evaluate its effectiveness both in a real sensor testbed and through simulation.
As wireless sensor networks continue to grow, so does the need for effective security mechanisms. The classical mechanisms, namely authentication and encryption, can prevent some outsider attacks;however, these mechan...
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The art and science of sensing and responding to dynamic data over vast areas through distributed network of assets has long been in existence for centuries. Much of the current and emerging developments in sensor-net...
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The art and science of sensing and responding to dynamic data over vast areas through distributed network of assets has long been in existence for centuries. Much of the current and emerging developments in sensor-networks and trusted computing have their metaphorical counterparts seen in history. Clear insights into the architecture and effective practices in command, control, communication, computation, collaboration and coordination (C*) have much to offer to the way we design and deploy new and innovative sensors as we continue to exploit latest developments in micro- and nano-scale sensors and systems. This paper presents a brief overview of how a complex Web of intelligent autonomous and heterogeneous sensors might be used in a dynamic environment. The key elements of enabling technologies and required capabilities are identified to facilitate a paradigm for sensors, driven by system level considerations
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