{"title":"Through-the-wall radar imaging using a distributed Quasi-Newton method","authors":"Haroon Raja, W. Bajwa, F. Ahmad","doi":"10.1109/ACSSC.2017.8335142","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335142","url":null,"abstract":"This paper considers a distributed network of through-the-wall imaging radars and provides a solution for accurate indoor scene reconstruction in the presence of multipath propagation. A sparsity-based method is proposed for eliminating ghost targets under imperfect knowledge of interior wall locations. Instead of aggregating and processing the observations at a central fusion station, joint scene reconstruction and estimation of interior wall locations is carried out in a distributed manner across the network. Using alternating minimization approach, the sparse scene is reconstructed using the recently proposed MDOMP algorithm, while the wall location estimates are obtained with a distributed quasi-Newton method (D-QN) proposed in this paper. The efficacy of the proposed approach is demonstrated using numerical simulation.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"224 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121307512","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Graph slepians to probe into large-scale network organization of resting-state functional connectivity","authors":"M. Preti, D. Ville","doi":"10.1109/ACSSC.2017.8335615","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335615","url":null,"abstract":"Functional magnetic resonance imaging (fMRI) is providing large amounts of data about brain function. Measuring correlations between spontaneous activity time courses from resting-state fMRI has revealed large-scale network organization. In the graph-based approach for functional connectivity analysis, a graph is built where nodes are brain regions and edge weights are pairwise correlations between the associated time courses. Here, we propose to apply recent approaches from graph signal processing to analyze fMRI data. First, the graph is constructed from structural connectivity, then, the corresponding graph spectrum is obtained such that the graph Slepian design can be deployed. In particular, graph Slepians are band-limited (i.e., using only graph Laplacian eigenvectors with lowest eigenvalues) with optimal energy concentration in predefined subgraphs. The subgraphs selected here are default-mode network (DMN) and fronto-parietal network (FPN), known as task-negative and — positive networks, respectively. While their activity appears anti-correlated during resting-state, a much more complicated interplay has been suggested recently using dynamic and time-resolved approaches. Preliminary results using data from the Human Connectome Project show that the proposed framework can direct the analysis to specific parts of the network and bring to light interactions between local and global aspects of network organization that were hidden before.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121500777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Radar detection in K-distributed clutter plus noise using L-statistics","authors":"J. Ritcey","doi":"10.1109/ACSSC.2017.8335532","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335532","url":null,"abstract":"Detection in long-tailed clutter is a challenging problem. Recently, the Generalized Likelihood Ratio Test (GLRT) in K-distributed clutter plus noise has been addressed. It has been shown that the minimum order-statistic detector works well to sort non-fluctuating point targets from clutter. We extend this work to show that, at little additional computational cost, linear combining of sorted values, L-statistics, can provide some additional performance gains, depending on the Clutter-to-Noise Ratio. Results are given primarily through Monte Carlo simulation.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121700583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Directional timing synchronization in wideband millimeter wave cellular systems with low-resolution ADCs","authors":"Dalin Zhu, R. Heath","doi":"10.1109/ACSSC.2017.8335131","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335131","url":null,"abstract":"We develop a new beamforming strategy for millimeter-wave systems to improve the frame timing synchronization performance under low-resolution analog-to-digital converters. In the proposed method, identical synchronization sequences are sent across a cluster of simultaneously probed synchronization beams. The beam codewords in the beam cluster are selected to maximize the received synchronization signal-to-quantization-plus-noise ratio (SQNR). Numerical results reveal that the frame timing synchronization performance of the proposed method outperforms the existing approach due to the improvement in the received synchronization SQNR.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"70 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114828481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Pilot decontamination under imperfect power control","authors":"Jitendra Tugnait","doi":"10.1109/ACSSC.2017.8335513","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335513","url":null,"abstract":"In a time-division duplex (TDD) multiple antenna system the channel state information (CSI) can be estimated using reverse training. In multicell multiuser massive MIMO systems, pilot contamination degrades CSI estimation performance and adversely affects massive MIMO system performance. In this paper we consider a subspace-based semi-blind approach where we have training data as well as information bearing data from various users (both in-cell and neighboring cells) at the base station (BS). Existing subspace approaches assume that the interfering users from neighboring cells are always at distinctly lower power levels at the BS compared to the in-cell users. In this paper we do not make any such assumption. Unlike existing approaches, the BS estimates the channels of all users: in-cell and significant neighboring cell users, i.e., ones with comparable power levels at the BS. We exploit both subspace method using correlation as well as blind source separation using higher-order statistics. The proposed approach is illustrated via simulation examples.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127957453","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Parallel GF(2n) multipliers","authors":"Trenton J. Grale, E. Swartzlander","doi":"10.1109/ACSSC.2017.8335505","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335505","url":null,"abstract":"Operations over polynomial Galois fields GF(2n) are employed in a variety of cryptographic systems. These operations include multiplication and reduction with respect to an irreducible polynomial modulus. Fast parallel multipliers can be designed but require substantial die area. Building on prior work, two fully parallel polynomial n× n multipliers are presented with O(log2 n) latency, which use lookup tables to store modular reduction terms.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131945328","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Omar Aldayel, Tiantong Guo, V. Monga, M. Rangaswamy
{"title":"Adaptive sequential refinement: A tractable approach for ambiguity function shaping in cognitive radar","authors":"Omar Aldayel, Tiantong Guo, V. Monga, M. Rangaswamy","doi":"10.1109/ACSSC.2017.8335406","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335406","url":null,"abstract":"Ambiguity function shaping continues to be one of the most challenging open problems in cognitive radar. Analytically, a complex quartic function should be optimized as a function of the radar waveform code. Practical considerations further require that the waveform be constant modulus, which exacerbates the issue and leads to a hard non-convex problem. We develop a new approach called Adaptive Sequential Refinement (ASR) to suppress the clutter returns for a desired range-Doppler, i.e. ambiguity function response. ASR solves the aforementioned optimization problem in a unique iterative manner such that the formulation is updated depending on the iteration index. We establish formally that: 1.) the problem in each step of the iteration has a closed form solution, and 2.) monotonic decrease of the cost function until convergence is guaranteed. Experimental validation shows that ASR produces a radar waveform with higher Signal to Interference Ratio (SIR) and superior ambiguity function shaping than state of the art alternatives even as its computational burden is orders of magnitude lower.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134115772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Whole brain reconstruction from multilayered sections of a mouse model of status epilepticus","authors":"Haoyi Liang, N. Dabrowska, J. Kapur, D. Weller","doi":"10.1109/ACSSC.2017.8335554","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335554","url":null,"abstract":"This research concerns confocal fluorescence microscopy imaging of the whole brain of C57BL/6 mice with single-cell resolution. These brains are too large for specimen holders in available 3D microscopes, so this research develops a set of volume reconstruction methods to reproduce a whole brain from multilayered, thin sections of the brain imaged using a confocal microscope. As the sections are in solution during imaging, their shapes warp differently, and their structures no longer align. The proposed two-stage reconstruction procedure consists of single-section correction and section-to-section alignment, towards producing a whole brain volume. In the first stage, the proposed method carefully unwarps the distorted shapes of each section. The second stage aligns prominent features between the layers of neighboring sections. This paper also newly considers how these stages influence each other in the broader context of whole brain volume reconstruction. Experimental results portraying each stage with real image data suggest that the proposed approach can produce consistent 3D volumes and largely correct the observed distortions.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134137828","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Latent variable models for hippocampal sequence analysis","authors":"E. Ackermann, C. Kemere, Kourosh Maboudi, K. Diba","doi":"10.1109/ACSSC.2017.8335439","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335439","url":null,"abstract":"The activity of ensembles of neurons within the hippocampus is thought to enable memory formation, storage, recall, and potentially decision making. During offline states (associated with sharp wave ripples, quiescence, or sleep), some of these neurons are reactivated in temporally-ordered sequences which are thought to enable associations across time and episodic memories spanning longer periods. However, analyzing these sequences of neural activity remains challenging. Here we build on recent approaches using latent variable models for hippocampal population codes, to detect so-called \"replay events\", and to build models of hippocampal sequences independent of animal behavior. We demonstrate that our approach can identify the same replay events as traditional Bayesian decoding approaches, and moreover, that it can detect nonlinear remote replay events that are difficult or impossible to detect with existing approaches.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"201 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134429719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Multiple interface brain and head models for EEG: A surface charge approach","authors":"F. J. Solisi, A. Papandreou-Suppappola","doi":"10.1109/ACSSC.2017.8335568","DOIUrl":"https://doi.org/10.1109/ACSSC.2017.8335568","url":null,"abstract":"Electroenecephalography (EEG) studies can be carried out using forward methods, where the scalp potential is first determined for given localized brain neural dipole sources. The recently introduced surface charge forward method addresses the forward problem by means of an integral equation where the accumulated charge at the boundaries between homogeneous regions is taken as the basic variable. We demonstrate the application of this method to the case of realistic head shapes with multiple homogenous regions and discuss the use of these results to source tracking problems.","PeriodicalId":296208,"journal":{"name":"2017 51st Asilomar Conference on Signals, Systems, and Computers","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2017-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133876062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}