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Shen, Yanning (author), Leus, G.J.T. (author)Graphs have well-documented merits for modeling complex systems, including financial, biological, and social networks. Network nodes can also include attributes such as age or gender of users in a social network. However, the size of real-world networks can be massive, and nodal attributes can be unavailable. Moreover, new nodes may emerge...conference paper 2019
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Gama, F. (author), Marques, Antonio G. (author), Leus, G.J.T. (author), Ribeiro, Alejandro (author)In this ongoing work, we describe several architectures that generalize convolutional neural networks (CNNs) to process signals supported on graphs. The general idea of the replace time invariant filters with graph filters to generate convolutional features and to replace pooling with sampling schemes for graph signals. The different...conference paper 2019
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Kazaz, T. (author), Coutino, Mario (author), Janssen, G.J.M. (author), Leus, G.J.T. (author), van der Veen, A.J. (author)Synchronization and ranging in internet of things (IoT) networks are challenging due to the narrowband nature of signals used for communication between IoT nodes. Recently, several estimators for range estimation using phase difference of arrival (PDoA) measurements of narrowband signals have been proposed. However, these estimators are based...conference paper 2019
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van der Meulen, P.Q. (author), Kruizinga, P. (author), Bosch, Johannes G. (author), Leus, G.J.T. (author)We consider a model-based ultrasound imaging scenario using a single transducer with a coding mask, and assume that the pulse-echo model is erroneously estimated, resulting in decreased imaging performance. Although the pulse-echo Green's function to each pixel has to be measured to obtain a good model, typically only forward-field...conference paper 2019
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Coutino, Mario (author), Leus, G.J.T. (author)As the size of the sensor network grows, synchronization starts to become the main bottleneck for distributed computing. As a result, efforts in several areas have been focused on the convergence analysis of asynchronous computational methods. In this work, we aim to cross-pollinate distributed graph filters with results in parallel computing...conference paper 2019
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Coutino, Mario (author), Isufi, E. (author), Maehara, Takanori (author), Leus, G.J.T. (author)In this work, we explore the limits of finite-time distributed consensus through the intersection of graph filters and matrix function theory. We focus on algorithms capable to compute the consensus exactly through filtering operations over a graph, and that have been proven to converge in finite time. In this context, we show that there...conference paper 2019
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Gama, F. (author), Marques, Antonio G. (author), Ribeiro, Alejandro (author), Leus, G.J.T. (author)Graph neural networks (GNNs) regularize classical neural networks by exploiting the underlying irregular structure supporting graph data, extending its application to broader data domains. The aggregation GNN presented here is a novel GNN that exploits the fact that the data collected at a single node by means of successive local exchanges...conference paper 2019
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Isufi, E. (author), Banelli, Paolo (author), Di Lorenzo, Paolo (author), Leus, G.J.T. (author)This work merges tools from graph signal processing and linear systems theory to propose sampling strategies for observing the initial state of a process evolving over a graph. The proposed method is ratified by a mathematical analysis that provides insights on the role played by the different actors, such as the graph topology, the process...conference paper 2019
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Aittomäki, Tuomas (author), Leus, G.J.T. (author)Graph filters are an essential part of signal processing on graphs enabling one to modify the spectral content of the graph signals. This paper proposes a graph filter optimization method with an exact control of the ripple on the passband and the stopband of the filter. The proposed filter design method is based on the sum-of-squares...conference paper 2019
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Gama, Fernando (author), Marques, Antonio G. (author), Leus, G.J.T. (author), Ribeiro, Alejandro (author)Convolutional neural networks (CNNs) restrict the, otherwise arbitrary, linear operation of neural networks to be a convolution with a bank of learned filters. This makes them suitable for learning tasks based on data that exhibit the regular structure of time signals and images. The use of convolutions, however, makes them unsuitable for...conference paper 2019
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van der Meulen, P.Q. (author), Kruizinga, P. (author), Bosch, J.G. (author), Leus, G.J.T. (author)We study the optimal design of an aperture coding mask, and the optimal sensing positions of a single ultrasound sensor with a scanning configuration. In previous works, we have shown that 3D ultrasound imaging is possible using a randomly shaped coding mask with randomly chosen sensing positions. Here we propose an optimization algorithm for...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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Gama, F. (author), Leus, G.J.T. (author), Marques, Antonio G. (author), Ribeiro, Alejandro (author)Convolutional neural networks (CNNs) are being applied to an increasing number of problems and fields due to their superior performance in classification and regression tasks. Since two of the key operations that CNNs implement are convolution and pooling, this type of networks is implicitly designed to act on data described by regular...conference paper 2018
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Ebihara, Tadashi (author), Leus, G.J.T. (author), Ogasawara, Hanako (author)In this paper, we propose a novel underwater acoustic communication scheme that achieves energy and spectrum efficiency simultaneously by combining Doppler-resilient orthogonal signal division multiplexing (D-OSDM) and multiple-input multiple-output (MIMO) signaling. We present both the transmitter and receiver processing for MIMO D-OSDM. We...conference paper 2018
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van der Meulen, P.Q. (author), Kruizinga, P. (author), Bosch, Johan G. (author), Leus, G.J.T. (author)High quality three dimensional ultrasound imaging is typically attained by increasing the amount of sensors, resulting in complex hardware. Compressing measurements before sensing addresses this problem, and could enable new clinical applications. We have developed an analogue compression technique, by positioning a plastic coding mask in...conference paper 2018
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Gama, F. (author), Marques, Antonio G. (author), Ribeiro, Alejandro (author), Leus, G.J.T. (author)Superior performance and ease of implementation have fostered the adoption of Convolutional Neural Networks (CNN s) for a wide array of inference and reconstruction tasks. CNNs implement three basic blocks: convolution, pooling and pointwise nonlinearity. Since the two first operations are well-defined only on regular-structured data such as...conference paper 2018
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Gama, F. (author), Isufi, E. (author), Leus, G.J.T. (author), Ribeiro, Alejandro (author)In this work, we jointly exploit tools from graph signal processing and control theory to drive a bandlimited graph signal that is being diffused on a random time-varying graph from a subset of nodes. As our main contribution, we rely only on the statistics of the graph to introduce the concept of controllability in the mean, and therefore...conference paper 2018
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Tohidi, E. (author), Behroozi, Hamid (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. However, the increased hardware cost (due to multiple transmitters and receivers), power consumption (due to multiple transmitters and pulses), and computational complexity (due to numerous pulses) form...conference paper 2018
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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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Mecklenbrauker, Christoph F. (author), Gerstoft, Peter (author), Leus, G.J.T. (author)Direction of arrival (DOA) estimation from array observations in a noisy environment is discussed. The source amplitudes are assumed to be correlated zero-mean complex Gaussian distributed with unknown covariance matrix. The DOAs and covariance parameters of plane waves are estimated from multi-snapshot sensor array data using sparse Bayesian...conference paper 2018