Distributed sampling and reconstruction of a physical field using an array of sensors is a problem of considerable interest in environmental monitoring applications of sensornetworks. Our recent work has focused on t...
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ISBN:
(纸本)1581138466
Distributed sampling and reconstruction of a physical field using an array of sensors is a problem of considerable interest in environmental monitoring applications of sensornetworks. Our recent work has focused on the sampling of bandlimited sensor fields. However, sensor fields are not perfectly bandlimited but typically have rapidly decaying spectra. In a classical sampling set-up it is possible to precede the A/D sampling operation with an appropriate analog anti-alia,sing filter. However, in the case of sensornetworks, this is infeasible since sampling must precede filtering. We show that even though the effects of aliasing on the reconstruction cannot be prevented due to the "filter-less" sampling constraint, they can be suitably controlled by oversampling and carefully reconstructing the field from the samples. We show using a dither-based scheme that it is possible to estimate non-bandlimited fields with a precision that depends on how fast the spectral content of the field decays. We develop a framework for analyzing non-bandlimited fields that lead to upper bounds on the maximum pointwise error for a spatial bit rate of R bits/meter. We present results for fields with exponentially decaying spectra as an illustration. In particular, we show that for fields f(t) with exponential tails;i.e., \F(omega)\ < pialphae(-a\omega\), the maximum pointwise error decays as c(2)e(-a1rootR) + c(3)1/rootRe(-2a1rootR) with spatial bit rate R bits/meter. Finally, we show that for fields with spectra that have a finite second moment, the distortion decreases as O((1/N)(2/3)) as the density of sensors, N, scales up to infinity. We show that if D is the targeted non-zero distortion, then the required (finite) rate R scales as O(1/rootDlog1/D).
Wireless sensornetworks are an important research area that has attracted a lot of attention in the past few years. Most of this attention, however, has focused on wireless sensor network collect scalar data such as ...
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ISBN:
(纸本)9781424455379
Wireless sensornetworks are an important research area that has attracted a lot of attention in the past few years. Most of this attention, however, has focused on wireless sensor network collect scalar data such as temperature and vibration. Scalar data is insufficient for many applications such as video surveillance and traffic monitoring. Whereas, camera sensors collect video data, which are rich in information and offer tremendous potential when used in wireless sensornetworks. Video sensornetworks continue to gain increase interest due to their ability to collect video information for a wide range of applications in recent years. However, knowledge about these types of networks is mostly related to visual algorithms, leaving the issues such as the coverage of video sensor network and the transmission of video data aside. In this paper, we first highlight the issues and opportunities of video sensor network. And then we discuss key research issue on video sensor network, specifically camera coverage problem, network architecture, and low-power video data processing and communication. Finally, we identify enabling approaches in this area.
Developing applications for wireless sensornetworks (WSN) is a complicated process because of the wide variety of WSN applications and low-level implementation details. Model-Driven Engineering offers an effective so...
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ISBN:
(纸本)9783642011115
Developing applications for wireless sensornetworks (WSN) is a complicated process because of the wide variety of WSN applications and low-level implementation details. Model-Driven Engineering offers an effective solution to WSN application developers by hiding the details of lower layers and raising the level of abstraction. However, balancing between abstraction level and unambiguity is challenging issue. This paper presents Baobab, a metamodeling framework for designing WSN applications and generating the corresponding code, to overcome the conflict between abstraction and reusability versus unambiguity. Baobab allows users to define functional and nonfunctional aspects of a system separately as software models, validate them and generate code automatically.
The proceedings contain 8 papers. The topics discussed include: processing proximity queries in sensornetworks;impact of multi-query optimization in sensornetworks;MeT: a real world oriented metadata management syst...
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The proceedings contain 8 papers. The topics discussed include: processing proximity queries in sensornetworks;impact of multi-query optimization in sensornetworks;MeT: a real world oriented metadata management system for semantic sensornetworks;network scheduling for data archiving applications in sensornetworks;transactional issues in sensor data management;energy-efficient handling of sensor failures;quality of service in stateful information filters;and intelligent system monitoring on large clusters.
This paper proposes to use a radial basis function (RBF) network to increase the separation performance of blind signal separation (BSS). Independent component analysis (ICA) is often used for BSS, but in general, ICA...
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ISBN:
(纸本)0780382927
This paper proposes to use a radial basis function (RBF) network to increase the separation performance of blind signal separation (BSS). Independent component analysis (ICA) is often used for BSS, but in general, ICA employs a sigmoid function to describe the probability distribution of signals in the process of learning. We attempt to describe the probability distribution of signals as accurately as possible in order to improve the performance of signal separation by ICA. The proposed method is applied to the signal separation problem of actual speech signals. The effectiveness of the proposed method has been confirmed by simulation experiments.
Multidimensional Scaling (MDS) has been recently applied to node localization in sensornetworks and gained some very impressive performance. MDS treats dissimilarities of pair-wise nodes directly as Euclidean distanc...
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ISBN:
(纸本)9781424416523
Multidimensional Scaling (MDS) has been recently applied to node localization in sensornetworks and gained some very impressive performance. MDS treats dissimilarities of pair-wise nodes directly as Euclidean distances and then makes use of the spectral decomposition of a doubly centered matrix of dissimilarities. However dissimilarities mainly estimated by Received Signal Strength (RSS) or by the Time of Arrival (TOA) of communication signal from the sender to the receiver used to suffer errors. From this observation, Nonmetric Multidimensional Scaling (NMDS) based only the rank order of the dissimilarities is proposed in this paper. Different from MDS, NMDS obtain insights into the nature of "perceived" dissimilarities which makes it more suitable to the problem of sensor localization. The experiment on real sensor network measurements of RSS and TOA shows the efficiency and novelty of NMDS for sensor localization problem in term of sensor location-estimated error.
This work is a survey on the usage of machine learning techniques in wireless sensornetworks (WSNs) and mobile ad-hoc networks (MANETs). Its focus lies on approaches for data routing. The goal of the work is two-fold...
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ISBN:
(纸本)9781424415014
This work is a survey on the usage of machine learning techniques in wireless sensornetworks (WSNs) and mobile ad-hoc networks (MANETs). Its focus lies on approaches for data routing. The goal of the work is two-fold: first, to classify and evaluate the most important existing and on-going research in the area and, second, to provide a guide for researchers wanting to apply machine learning techniques. For this, it also gives short description of the most appropriate algorithms and suggests for which scenarios they can be best used.
The events which are monitored in wireless sensornetworks(WSNs) always happens randomly, so the network traffic is dynamic. This paper proposes a traffic adaptive asynchronous media access control(MAC) protocol of wi...
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ISBN:
(纸本)9781509055210
The events which are monitored in wireless sensornetworks(WSNs) always happens randomly, so the network traffic is dynamic. This paper proposes a traffic adaptive asynchronous media access control(MAC) protocol of wireless sensor network (TAASMAC). TAASMAC gets the number of packets which are waiting to be sent in the queue, according to the number, TAASMAC can get the current information of network traffic, and changes the sleep time. The TAASMAC also solves the broadcasting problem in asynchronous MAC. This paper uses NS2 to validate the TAASMAC, and the results show that the TAASMAC gets lower energy consumption while in low network traffic condition, and gets lower delay while in high network traffic condition.
In this paper, we describe an experiment where we gathered audio information from a series of conventional wired micro-phones installed in a typical university setting. We also obtained visual information from cameras...
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Because of the battery replacement confined by physical conditions, the battery energy limit of the sensor nodes becomes one of the most critical constraints in the design of the entire sensor network, which directly ...
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