The paper studies distributed static parameter (vector) estimation in sensor networks with nonlinear observation models and noisy intersensor communication. It introduces separably estimable observation models that ge...
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The paper studies distributed static parameter (vector) estimation in sensor networks with nonlinear observation models and noisy intersensor communication. It introduces separably estimable observation models that generalize the observability condition in linear centralized estimation to nonlinear distributedestimation. It studies two distributedestimation algorithms in separably estimable models, the NU (with its linear counterpart LU) and the NLU. Their update rule combines a consensus step (where each sensor updates the state by weight averaging it with its neighbors' states) and an innovation step (where each sensor processes its local current observation). This makes the three algorithms of the consensus + innovations type, very different from traditional consensus. This paper proves consistency (all sensors reach consensus almost surely and converge to the true parameter value), efficiency, and asymptotic unbiasedness. For LU and NU, it proves asymptotic normality and provides convergence rate guarantees. The three algorithms are characterized by appropriately chosen decaying weight sequences. Algorithms LU and NU are analyzed in the framework of stochastic approximation theory;algorithm NLU exhibits mixed time-scale behavior and biased perturbations, and its analysis requires a different approach that is developed in this paper.
distributedestimation over multitask networks, where the target parameter vectors (tasks) for different nodes can be different, has received much attention recently. In this article, we consider some practical applic...
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distributedestimation over multitask networks, where the target parameter vectors (tasks) for different nodes can be different, has received much attention recently. In this article, we consider some practical application scenarios, where there are some similarities between tasks, and thus, intertask cooperation is beneficial to improve the estimation performance of nodes. In most of the existing multitask learning studies, local estimates are directly transmitted between neighboring nodes, and then, the adaptive combination strategy is adopted to achieve intertask cooperation. However, when the target parameter vectors contain sensitive information, direct transmission of local estimates may result in serious privacy breaches. To tackle this problem, we propose a privacy-preserving distributed multitask learning algorithm for collaborative estimation over networks. The proposed algorithm is implemented by a secure multiparty computation protocol designed on an organic combination of multiplicative/additive mask and additively homomorphic encryption technique. While allowing each node to adaptively cooperate with its neighbors, this protocol also preserves the privacy of the local estimates. Besides, we present a thorough privacy analysis of the proposed algorithm. Simulation results show that the proposed algorithm can effectively protect each node's task against leakage without sacrificing the performance of estimation.
The goal of this paper is to reliably estimate a vector of unknown deterministic parameters associated with an underlying function at a fusion center of a wireless sensor network based on its noisy samples made at dis...
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ISBN:
(纸本)9780819490827
The goal of this paper is to reliably estimate a vector of unknown deterministic parameters associated with an underlying function at a fusion center of a wireless sensor network based on its noisy samples made at distributed local sensors. A set of noisy samples of a deterministic function characterized by a finite set of unknown parameters to be estimated is observed by distributed sensors. The parameters to be estimated can be some attributes associated with the underlying function, such as its height, its center, its variances in different directions, or even the weights of its specific components over a predefined basis set. Each local sensor processes its observation and sends its processed sample to a fusion center through parallel impaired communication channels. Two local processing schemes, namely analog and digital, are considered. In the analog local processing scheme, each sensor transmits an amplified version of its local analog noisy observation to the fusion center, acting like a relay in a wireless network. In the digital local processing scheme, each sensor quantizes its noisy observation before transmitting it to the fusion center. A flat-fading channel model is considered between the local sensors and fusion center. The fusion center combines all of the received locally-processed observations and estimates the vector of unknown parameters of the underlying function. Two different well-known estimation techniques, namely maximum-likelihood (ML), for both analog and digital local processing schemes, and expectation maximization (EM), for digital local processing scheme, are considered at the fusion center. The performance of the proposed distributed parameter estimation system is investigated through simulation of practical scenarios for a sample underlying function.
In recent years because of substantial use of wireless sensor network the distributedestimation has attracted the attention of many researchers. Two popular learning algorithms: incremental least mean square (ILMS) a...
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In recent years because of substantial use of wireless sensor network the distributedestimation has attracted the attention of many researchers. Two popular learning algorithms: incremental least mean square (ILMS) and diffusion least mean square (DLMS) have been reported for distributedestimation using the data collected from sensor nodes. But these algorithms, being derivative based, have a tendency of providing local minima solution particularly for minimization of multimodal cost function. Hence for problems like distributedparameters estimation of IIR systems, alternative distributed algorithms are required to be developed. Keeping this in view the present paper proposes two population based incremental particle swarm optimization (IPSO) algorithms for estimation of parameters of noisy IIR systems. But the proposed IPSO algorithms provide poor performance when the measured data is contaminated with outliers in the training samples. To alleviate this problem the paper has proposed a robust distributed algorithm (RDIPSO) for IIR system identification task. The simulation results of benchmark HR systems demonstrate that the proposed algorithms provide excellent identification performance in all cases even when the training samples are contaminated with outliers. (C) 2013 Elsevier Inc. All rights reserved.
This paper investigates a distributed recursive projection identification problem with binaryvalued observations built on a sensor network,where each sensor in the sensor network measures partial information of the un...
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This paper investigates a distributed recursive projection identification problem with binaryvalued observations built on a sensor network,where each sensor in the sensor network measures partial information of the unknown parameter only,but each sensor is allowed to communicate with its neighbors.A distributed recursive projection algorithm is proposed based on a specific projection operator and a diffusion *** authors establish the upper bound of the accumulated regrets of the adaptive predictor without any requirement of excitation ***,the convergence of the algorithm is given under the bounded cooperative excitation condition,which is more general than the previously imposed independence or persistent excitations on the system regressors and maybe the weakest one under binary observations.A numerical example is supplied to demonstrate the theoretical results and the cooperative effect of the sensors,which shows that the whole network can still fulfill the estimation task through exchanging information between sensors even if any individual sensor cannot.
The traditional least-squares based diffusion least mean squares is not robust against outliers present in either desired data or input data. The diffusion minimum generalised rank (GR) norm algorithm proposed in the ...
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The traditional least-squares based diffusion least mean squares is not robust against outliers present in either desired data or input data. The diffusion minimum generalised rank (GR) norm algorithm proposed in the earlier works of the authors was able to effectively estimate the parameter of interest in presence of outliers in both desired and input data. However, this manuscript deals with the robust distributedestimation over distributed networks exploiting sparsity underlying in the system model. The proposed algorithm is based on both GR norm and compressive sensing, where GR norm ensures robustness against outliers in input as well as desired data. The techniques from compressive sensing endow the network with adaptive learning of the sparse structure form the incoming data in real-time and it also enables tracking of the sparsity variations of the system model. The mean and mean square convergence of the proposed algorithm are analysed and the conditions under which the proposed algorithm outperforms the unregularised diffusion GR norm algorithm are also investigated. The proposed algorithms are validated for three different applications namely distributed parameter estimation, tracking and distributed power spectrum estimation.
In wireless sensor networks, estimating a global parameter from locally obtained measurements via local interactions is known as the distributed parameter estimation problem. Solving these problems often require the d...
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ISBN:
(纸本)9781479981311
In wireless sensor networks, estimating a global parameter from locally obtained measurements via local interactions is known as the distributed parameter estimation problem. Solving these problems often require the deployment of distributed optimization algorithms that rely on a constant exchange of information among the sensor nodes. This makes such distributed algorithms vulnerable to attackers or malicious nodes that want to gain access to private information regarding the network. Based on the sliding mode control scheme, here we present a novel approach to infer sensitive information (e.g., gradient or private parameters of the local objective function) regarding a node of interest by intercepting the communication between the nodes. The effectiveness of the proposed approach is illustrated in a representative example of distributed event localization using an acoustic sensor network.
In this paper, we study the problem of distributed normalized least-mean squares(NLMS) estimation over multi-agent networks, where all nodes collaborate to estimate a common parameter of *** consider the situations th...
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In this paper, we study the problem of distributed normalized least-mean squares(NLMS) estimation over multi-agent networks, where all nodes collaborate to estimate a common parameter of *** consider the situations that all nodes in the network are corrupted by both input and output noise. This yields into biased estimates by the distributed NLMS algorithms. In our analysis, we take all the noise into consideration and prove that the bias is dependent on the input noise variance. Therefore, we propose a bias compensation method to remove the noise-induced bias from the estimated results. In our development, we first assume that the variances of the input noise are known a priori and develop a series of distributed-based bias-compensated NLMS(BCNLMS) methods. Under various practical scenarios, the input noise variance is usually unknown a priori, therefore it is necessary to first estimate for its value before bias removal. Thus, we develop a real-time estimation method for the input noise variance, which overcomes the unknown property of this noise. Moreover, we perform some main analysis results of the proposed distributed BCNLMS algorithms. Furthermore, we illustrate the performance of the proposed distributed bias compensation method via graphical simulation results.
In this paper, we study the problem of distributed bias-compensated recursive least-squares(BCRLS) estimation over multi-agent networks, where the agents collaborate to estimate a common parameter of interest. We cons...
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In this paper, we study the problem of distributed bias-compensated recursive least-squares(BCRLS) estimation over multi-agent networks, where the agents collaborate to estimate a common parameter of interest. We consider the situation where both input and output of each agent are corrupted by unknown additive noise. Under this condition, traditional recursive least-squares(RLS) estimator is biased, and the bias is induced by the input noise variance. When the input noise variance is available, the effect of the noise-induced bias can be removed at the expense of an increase in estimation variance. Fortunately, it has been illustrated that distributed collaboration between agents can effectively reduce the variance and can improve the stability of the estimator. Therefore, a distributed incremental BC-RLS algorithm and its simplified version are proposed in this paper. The proposed algorithms can collaboratively obtain the estimates of the unknown input noise variance and remove the effect of the noise-induced bias. Then consistent estimation of the unknown parameter can be achieved in an incremental fashion. Simulation results show that the incremental BC-RLS solutions outperform existing solutions in some enlightening ways.
In this work, we present low-complexity variable forgetting factor (VFF) techniques for diffusion recursive least squares (DRLS) algorithms. Particularly, we propose low-complexity VFF-DRLS algorithms for distributed ...
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In this work, we present low-complexity variable forgetting factor (VFF) techniques for diffusion recursive least squares (DRLS) algorithms. Particularly, we propose low-complexity VFF-DRLS algorithms for distributedparameter and spectrum estimation in sensor networks. For the proposed algorithms, they can adjust the forgetting factor automatically according to the posteriori error signal. We develop detailed analyses in terms of mean and mean square performance for the proposed algorithms and derive mathematical expressions for the mean square deviation (MSD) and the excess mean square error (EMSE). The simulation results show that the proposed low-complexity VFF-DRLS algorithms achieve superior performance to the existing DRLS algorithm with fixed forgetting factor when applied to scenarios of distributedparameter and spectrum estimation. Besides, the simulation results also demonstrate a good match for our proposed analytical expressions.
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