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Ramamohan, Krishnaprasad Nambur (author), Chepuri, Sundeep Prabhakar (author), Comesana, Daniel Fernandez (author), Leus, G.J.T. (author)In this work, we consider the self-calibration problem of joint calibration and direction-of-Arrival (DOA) estimation using acoustic sensor arrays. Unlike many previous iterative approaches, we propose solvers that can be readily used for both linear and non-linear arrays for jointly estimating the sensor gain, phase errors, and the source...journal article 2023
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Sharma, Shubham (author), Coutino, Mario (author), Chepuri, Sundeep Prabhakar (author), Leus, G.J.T. (author), Hari, K. V.S. (author)The design of feasible trajectories to traverse the k-space for sampling in magnetic resonance imaging (MRI) is important while considering ways to reduce the scan time. Over the recent years, non-Cartesian trajectories have been observed to result in benign artifacts and being less sensitive to motion. In this paper, we propose a generalized...journal article 2020
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Han, Jing (author), Chepuri, Sundeep Prabhakar (author), Leus, G.J.T. (author)Orthogonal signal-division multiplexing (OSDM) has recently emerged as a promising modulation scheme for underwater acoustic communications. Although providing more flexibility in system design, it suffers from a special interference structure over time-varying channels. To enable reliable OSDM equalization, we propose a joint channel impulse...journal article 2020
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Bushnaq, Osama M. (author), Chaaban, Anas (author), Chepuri, Sundeep Prabhakar (author), Leus, G.J.T. (author), Al-Naffouri, Tareq Y. (author)Optimal sensor selection for source parameter estimation in energy harvesting Internet of Things (IoT) networks is studied in this paper. Specifically, the focus is on the selection of the sensor locations which minimizes the estimation error at a fusion center, and to optimally allocate power and bandwidth for each selected sensor subject to...journal article 2020
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Coutino, Mario (author), Chepuri, Sundeep Prabhakar (author), Maehara, Takanori (author), Leus, G.J.T. (author)To analyze and synthesize signals on networks or graphs, Fourier theory has been extended to irregular domains, leading to a so-called graph Fourier transform. Unfortunately, different from the traditional Fourier transform, each graph exhibits a different graph Fourier transform. Therefore to analyze the graph-frequency domain properties of...journal article 2020
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Nambur Ramamohan, K. (author), Chepuri, S.P. (author), Comesana, Daniel Fernandez (author), Leus, G.J.T. (author)In this paper, the focus is on the gain and phase calibration of sparse sensor arrays to localize more sources than the number of physical sensors. The proposed technique is a blind calibration method as it does not require any calibrator sources. Joint estimation of the gain errors, phase errors, and source directions is a complicated non...conference paper 2019
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Han, J. (author), Chepuri, S.P. (author), Zhang, Qunfei (author), Leus, G.J.T. (author)Orthogonal signal-division multiplexing (OSDM) is a promising modulation scheme that provides a generalized framework to unify orthogonal frequency-division multiplexing (OFDM) and single-carrier frequency-domain equalization. By partitioning each data block into vectors, it allows for a flexible configuration to trade off resource management...journal article 2019
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Tohidi, E. (author), Coutino, Mario (author), Chepuri, S.P. (author), Behroozi, Hamid (author), Nayebi, Mohammad Mahdi (author), Leus, G.J.T. (author)Multiple-input multiple-output (MIMO) radar is known for its superiority over conventional radar due to its antenna and waveform diversity. Although higher angular resolution, improved parameter identifiability, and better target detection are achieved, the hardware costs (due to multiple transmitters and multiple receivers) and high-energy...journal article 2019
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Ortiz-Jimenez, Guillermo (author), Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)We consider the problem of designing sparse sampling strategies for multidomain signals, which can be represented using tensors that admit a known multilinear decomposition. We leverage the multidomain structure of tensor signals and propose to acquire samples using a Kronecker-structured sensing function, thereby circumventing the curse of...journal article 2019
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Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)In this paper, we propose sensor selection strategies, based on convex and greedy approaches, for designing sparse samplers for composite detection. Particularly, we focus our attention on sparse samplers for matched subspace detectors. Differently from previous works, that mostly rely on random matrices to perform compression of the sub...conference paper 2018
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Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)Detection of a signal under noise is a classical signal processing problem. When monitoring spatial phenomena under a fixed budget, i.e., either physical, economical or computational constraints, the selection of a subset of available sensors, referred to as sparse sensing, that meets both the budget and performance requirements is highly...journal article 2018
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Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)In this work, we address the problem of identifying the underlying network structure of data. Different from other approaches, which are mainly based on convex relaxations of an integer problem, here we take a distinct route relying on algebraic properties of a matrix representation of the network. By describing what we call possible...conference paper 2018
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Segarra, Santiago (author), Chepuri, S.P. (author), Marques, Antonio G. (author), Leus, G.J.T. (author)Stationarity is a cornerstone property that facilitates the analysis and processing of random signals in the time domain. Although time-varying signals are abundant in nature, in many contemporary applications the information of interest resides in more irregular domains that can be conveniently represented using a graph. This chapter reviews...book chapter 2018
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Chepuri, S.P. (author), Eldar, Yonina C. (author), Leus, G.J.T. (author)In this paper the focus is on sampling and reconstruction of signals supported on nodes of arbitrary graphs or arbitrary signals that may be represented using graphs, where we extend concepts from generalized sampling theory to the graph setting. To recover such signals from a given set of samples, we develop algorithms that incorporate prior...conference paper 2018
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Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)In this work, we introduce subset selection strategies for signal reconstruction based on kernel methods, particularly for the case of kernel-ridge regression. Typically, these methods are employed for exploiting known prior information about the structure of the signal of interest. We use the mean squared error and a scalar function of the...conference paper 2018
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Nambur Ramamohan, K. (author), Chepuri, S.P. (author), Comesana, Daniel Fernandez (author), Pousa, Graciano Carrillo (author), Leus, G.J.T. (author)In this paper, we present a calibration algorithm for acoustic vector sensors arranged in a uniform linear array configuration. To do so, we do not use a calibrator source, instead we leverage the Toeplitz blocks present in the data covariance matrix. We develop linear estimators for estimating sensor gains and phases. Further, we discuss the...conference paper 2018
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Chepuri, S.P. (author), Coutino, Mario (author), Marques, Antonio G. (author), Leus, G.J.T. (author)An analytical algebraic approach for distributed network identification is presented in this paper. The information propagation in the network is modeled using a state-space representation. Using the observations recorded at a single node and a known excitation signal, we present algorithms to compute the eigenfrequencies and eigenmodes of...conference paper 2018
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Ortiz-Jimenez, Guillermo (author), Coutino, Mario (author), Chepuri, S.P. (author), Leus, G.J.T. (author)In this paper, we consider the problem of subsampling and reconstruction of signals that reside on the vertices of a product graph, such as sensor network time series, genomic signals, or product ratings in a social network. Specifically, we leverage the product structure of the underlying domain and sample nodes from the graph factors. The...conference paper 2018
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Pizzo, A. (author), Chepuri, S.P. (author), Leus, G.J.T. (author)In this paper we focus on the relative position and orientation estimation between rigid bodies in an anchorless scenario. Several sensor units are installed on the rigid platforms, and the sensor placement on the rigid bodies is known beforehand (i.e., relative locations of the sensors on the rigid body are known). However, the absolute...conference paper 2016