This paper presents a novel time synchronization method in real-time wireless sensor networks. Firstly, time synchronization algorithms in common distributed system are reviewed and essential requirements in the desig...
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ISBN:
(纸本)078039335X
This paper presents a novel time synchronization method in real-time wireless sensor networks. Firstly, time synchronization algorithms in common distributed system are reviewed and essential requirements in the design of synchronization methods for wireless sensor network are proposed. Then, Reference Broadcast Synchronization (RBS), a very efficient method, is introduced and the probabilistic technique is applied to RBS in order to improve the performance. After that, a new method, namely partial delay measurement time synchronization, is proposed in this paper to optimize RBS further. At last, the algorithm is implemented on MICA, a wireless sensor platform, and the results illustrate the feasibility and reliability of the new method. It is shown theoretically and experimentally that the probabilistic time synchronization introduced in this paper is able to acquire satisfactory accuracy with less computational costs than such algorithms developed in common distributedsystems.
The widespread dissemination of small-scale sensor nodes has sparked interest in a powerful new database abstraction for sensor networks: Clients "program" the sensors through queries in a high-level declara...
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ISBN:
(纸本)3540264221
The widespread dissemination of small-scale sensor nodes has sparked interest in a powerful new database abstraction for sensor networks: Clients "program" the sensors through queries in a high-level declarative language permitting the system to perform the low-level optimizations necessary for energy-efficient query processing. In this paper we consider multi-query optimization for aggregate queries on sensor networks. We develop a set of distributed algorithms for processing multiple queries that incur minimum communication while observing the computational limitations of the sensor nodes. Our algorithms support incremental changes to the set of active queries and allow for local repairs to routes in response to node failures. A thorough experimental analysis shows that our approach results in significant energy savings, compared to previous work.
The literature on programming sensor networks has focused so far on providing higher-level abstractions for expressing local node behavior. Kairos is a natural next step in sensor network programming in that it allows...
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ISBN:
(纸本)3540264221
The literature on programming sensor networks has focused so far on providing higher-level abstractions for expressing local node behavior. Kairos is a natural next step in sensor network programming in that it allows the programmer to express, in a centralized fashion, the desired global behavior of a distributed computation on the entire sensor network. Kairos' compile-time and run-time subsystems expose a small set of programming primitives, while hiding from the programmer the details of distributed-code generation and instantiation, remote data access and management, and inter-node program flow coordination. In this paper, we describe Kairos' programming model, and demonstrate its suitability, through actual implementation, for a variety of distributed programs-both infrastructure services and signal processing tasks-typically encountered in sensor network literature: routing tree construction, localization, and object tracking. Our experimental results suggest that Kairos does not adversely affect the performance or accuracy of distributed programs, while our implementation experiences suggest that it greatly raises the level of abstraction presented to the programmer.
We present a distributed, localized and integrated approach for establishing both low-level (i.e. exploration of 1-hop neighbors, interference avoidance) and high-level (a subgraph of the unit-disk graph) infrastructu...
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ISBN:
(纸本)3540264221
We present a distributed, localized and integrated approach for establishing both low-level (i.e. exploration of 1-hop neighbors, interference avoidance) and high-level (a subgraph of the unit-disk graph) infrastructure in wireless sensor networks. More concretely, our proposed scheme constructs a subgraph of the unit-disk graph which is connected, planar and has power stretch factor of I (the well-known Gabriel graph intersected with the unit disk-graph) and - most importantly - deals explicitly with the problem of interference between nearby stations. Due to our interleaved approach of constructing low- and high-level infrastructure simultaneously, this results in considerable improvements in running time when applied in dense wireless networks. To substantiate the advantages of our approach, we introduce a novel distribution model inspired by actual sensing applications and analyze our new approach in that framework.
In this paper, we present two techniques. The first technique called Privacy Sensitive Information dilUtin Mechanism (PSIUM) is able to prevent the misuse of data by a service provider by using a mixture of true and f...
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ISBN:
(纸本)0769523153
In this paper, we present two techniques. The first technique called Privacy Sensitive Information dilUtin Mechanism (PSIUM) is able to prevent the misuse of data by a service provider by using a mixture of true and false sensor data. The second technique protects privacy sensitive information from being revealed to an attacker through traffic analysis by using a combination of frequently changing pseudonyms and dummy traffic.
Recent research has shown that using a mobile element to collect and carry data mechanically from a sensor network has many advantages over static multihop routing. We have an implementation as well employing a single...
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ISBN:
(纸本)3540264221
Recent research has shown that using a mobile element to collect and carry data mechanically from a sensor network has many advantages over static multihop routing. We have an implementation as well employing a single mobile element. But the network scalability and traffic may make a single mobile element insufficient. In this paper we investigate the use of multiple mobile elements. In particular, we present load balancing algorithm which tries to balance the number of sensor nodes each mobile element services. We show by simulation the benefits of load balancing.
sensor nodes in a distributedsensor network can fail due to a variety of reasons, e.g., harsh weather conditions, sabotage, battery failure, and component wear-out. Since many wireless sensor networks are intended to...
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ISBN:
(纸本)3540264221
sensor nodes in a distributedsensor network can fail due to a variety of reasons, e.g., harsh weather conditions, sabotage, battery failure, and component wear-out. Since many wireless sensor networks are intended to operate in an unattended manner after deployment, failing nodes cannot be replaced or repaired during field operation. Therefore, by designing the network to be fault-tolerant, we can ensure that a wireless sensor network can perform its surveillance and tracking tasks even when some nodes in the network fail. In this paper, we describe a fault-tolerant self-organization scheme that designates a set of backup nodes to replace failed nodes and maintain a backbone for coverage and communication. This scheme has been implemented on top of an energy-efficient self-organization technique for sensor networks. The proposed fault-tolerance-node selection procedure can tolerate a large number of node failures, without losing either sensing coverage or communication connectivity.
In surveillance and tracking applications, wireless sensor nodes collectively monitor the existence of intruding targets. In this paper, we derive closed form results for predicting surveillance performance attributes...
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ISBN:
(纸本)3540264221
In surveillance and tracking applications, wireless sensor nodes collectively monitor the existence of intruding targets. In this paper, we derive closed form results for predicting surveillance performance attributes, represented by detection probability and average detection delay of intruding targets, based on tunable system parameters, represented by node density and sleep duty cycle. The results apply to both stationary and mobile targets, and shed light on the fundamental connection between aspects of sensing quality and deployment choices. We demonstrate that our results are robust to realistic sensing models, which are proposed based on experimental measurements of passive infrared sensors. We also validate the correctness of our results through extensive simulations.
Wireless sensor networks have posed a number of challenging problems such as localization, deployment and tracking, etc. One of the interesting problems is the calculation of the coverage path for sensor networks. In ...
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ISBN:
(纸本)0769524052
Wireless sensor networks have posed a number of challenging problems such as localization, deployment and tracking, etc. One of the interesting problems is the calculation of the coverage path for sensor networks. In this paper we design a localized algorithm to solve the worst coverage problem first introduced by Meguerdichian et al. All nodes cooperate to construct the worst coverage path with their one-hop neighbors' information. Also, the correctness of the algorithm is proved under the diminishing model formally.
Embedded systems are often distributed and deployed in various environments. Wireless sensor nodes deposited in various places provide light, temperature, humidity, and other measurements. Wireless nodes attached to c...
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ISBN:
(纸本)0780393058
Embedded systems are often distributed and deployed in various environments. Wireless sensor nodes deposited in various places provide light, temperature, humidity, and other measurements. Wireless nodes attached to circuits or appliances sense the current or control the usage. Wireless sensor networks are application-specific. Because of this they have to involve both software and hardware. They also use protocols which relate to both the application and wireless network. The applications using wireless sensor networks are the consumer devices supporting multimedia applications, for example, personal digital assistants, network computers, and mobile communication devices. Emerging embedded systems run multiple applications such as Web-browsers, audio and video communication applications. We describe design issues in wireless networks to support sensors and embedded systems communication and information processing.
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