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Sparse deep predictive coding captures contour integration capabilities of the early visual system

PLOS COMPUTATIONAL BIOLOGY 2021年第1期17卷 e1008629-e1008629页

作者： Boutin, Victor Franciosini, Angelo Chavane, Frederic Ruffier, Franck Perrinet, Laurent Aix Marseille Univ Inst Neurosci Timone CNRS Marseille France Aix Marseille Univ CNRS ISM Marseille France

Both neurophysiological and psychophysical experiments have pointed out the crucial role of recurrent and feedback connections to process context-dependent information in the early visual cortex. While numerous models have accounted for feedback effects at either neural or representational level, none of them were able to bind those two levels of analysis. Is it possible to describe feedback effects at both levels using the same model? We answer this question by combining Predictive coding (PC) and Sparse coding (SC) into a hierarchical and convolutional framework applied to realistic problems. In the Sparse Deep Predictive coding (SDPC) model, the SC component models the internal recurrent processing within each layer, and the PC component describes the interactions between layers using feedforward and feedback connections. Here, we train a 2-layered SDPC on two different databases of images, and we interpret it as a model of the early visual system (V1 & V2). We first demonstrate that once the training has converged, SDPC exhibits oriented and localized receptive fields in V1 and more complex features in V2. Second, we analyze the effects of feedback on the neural organization beyond the classical receptive field of V1 neurons using interaction maps. These maps are similar to association fields and reflect the Gestalt principle of good continuation. We demonstrate that feedback signals reorganize interaction maps and modulate neural activity to promote contour integration. Third, we demonstrate at the representational level that the SDPC feedback connections are able to overcome noise in input images. Therefore, the SDPC captures the association field principle at the neural level which results in a better reconstruction of blurred images at the representational level. Author summary One often compares biological vision to a camera-like system where an image would be processed according to a sequence of successive transformations. In particular, this "feedforward"

关键词： Neurons coding mechanisms Vision Visual cortex Neurophysiology convolutional coding Sensory perception Visual system

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Proposal of New Decision Feedback Carrier Synchronization Method for Meteor Burst Communications

Proposal of New Decision Feedback Carrier Synchronization Me...

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International Symposium on Information Theory and its Applications (ISITA)

作者： Komatsubara, Keisuke Mukumoto, Kaiji Wada, Tadahiro Shizuoka Univ Grad Sch Engn Naka Ku Johoku 3-5-1 Hamamatsu Shizuoka 4328561 Japan

ISBN: (纸本)9784885522673

We have previously proposed Go-Back-i symbol automatic repeat request (GBi-ARQ) scheme appropriate to meteor burst communications. The GBi-ARQ scheme can achieve symbol-wise ARQ by using the Viterbi decoder for convolutional codes. In this paper, we propose a new carrier synchronization method appropriate to the GBi-ARQ scheme. The method can efficiently estimate carrier phase and frequency offset by using a pair of simple recursive equations for each survivor of the Viterbi algorithm.

关键词： carrier synchronization Viterbi decoders Viterbi algorithm decision feedback Automatic repeat request carrier phase convolutional coding FREQUENCY SHIFT Survivors iodine METEOR SHOWERS Pairing

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Energy-Efficient Vision on the PULP Platform for Ultra-Low Power Parallel Computing

Energy-Efficient Vision on the PULP Platform for Ultra-Low P...

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IEEE Workshop on Signal Processing Systems (SiPS)

作者： Conti, Francesco Rossi, Davide Pullini, Antonio Loi, Igor Benini, Luca Univ Bologna Dept Elect Elect & Informat Engn Bologna Italy Swiss Fed Inst Technol Integrated Syst Lab Zurich Switzerland

ISBN: (纸本)9781479965885

Many-core architectures structured as fabrics of tightly-coupled clusters have shown promising results on embedded computer vision benchmarks, providing state-of-art performance with a reduced power budget. We propose PULP (Parallel processing Ultra-Low Power platform), an architecture built on clusters of tightly-coupled OpenRISC ISA cores, with advanced techniques for fast performance and energy scalability that exploit the capabilities of the STMicroelectronics UTB FD-SOI 28nm technology. As a use case for PULP, we show that a computationally demanding vision kernel based on convolutional Neural Networks can be quickly and efficiently switched from a low power, low frame-rate operating point to a high frame-rate one when a detection is performed. Our results show that PULP performance can be scaled over a 1x-354x range, with a peak performance/power efficiency of 211 GOPS/W.

关键词： Benchmark testing Clocks Computer architecture convolutional codes Kernel Parallel processing System-on-chip PARALLEL PROCESSING (COMPUTERS) Benchmark testing system-on-chip convolutional coding Computer Architecture Pulp Timing devices Kernel core construction tight coupling Sight Seeds

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Performance of Anti-Jamming Techniques with Bit Interleaving in OFDM-Based Tactical Communications 6

Performance of Anti-Jamming Techniques with Bit Interleaving...

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6th International Conference on Information Technology and Electrical Engineering (ICITEE)

作者： Puspitaningayu, Pradini Hendrantoro, Gamantyo Univ Negeri Surabaya Elect Engn Fac Engn Surabaya Indonesia Inst Teknol Sepuluh Nopember Elect Engn Fac Ind Technol Surabaya Indonesia

ISBN: (纸本)9781479953035

Tactical communications is a communication system which is applied to a military operation with some strict requirements compared to a commercial communication system. One of the important requirement is its security. This communication has a high risk to be attacked by jamming which generated by the adversary. The other important requirement is network flexibility to handle its high mobility and information exchange in a big order. To fulfil those special requirement of tactical communication, OFDM system is equipped with channel coding and interleaving to handle information damage caused by jamming. The jamming strategy used in this research is single-tone and multitone jamming which strike while information signal pass the AWGN channel. In this research,we evaluate the performance of OFDM system which is equipped with convolutional Encoder and Inter leaver with various schemes. By using a half-rate convolutional encoder, for both parameters BER and interleaving gain, helical-scan interleaver scheme shows the best performance among block and random interleaver. However due to its complexity in applying this scheme, block interleaver which is the second best is preferred.

关键词： Jamming convolutional coding Interleaving

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Toward Scalable Source Level Accuracy Analysis for Floating-point to Fixed-point Conversion 33

Toward Scalable Source Level Accuracy Analysis for Floating-...

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33rd IEEE/ACM International Conference on Computer-Aided Design (ICCAD)

作者： Deest, Gael Yuki, Tomofumi Sentieys, Olivier Derrien, Steven Univ Rennes 1 F-35014 Rennes France Inria Rocquencourt France

ISBN: (纸本)9781479962785

In embedded systems, many numerical algorithms are implemented with fixed-point arithmetic to meet area cost and power constraints. Fixed-point encoding decisions can significantly affect cost and performance. To evaluate their impact on accuracy, designers resort to simulations. Their high running-time prevents thorough exploration of the design-space. To address this issue, analytical modeling techniques have been proposed, but their applicability is limited by scalability issues. In this paper, we extend these techniques to a larger class of programs. We use polyhedral methods to extract a more compact, graph-based representation of the program. We validate our approach with a several image and signal processing algorithms.

关键词： embedded systems fixed point arithmetic floating point arithmetic graph theory signal processing analytical modeling techniques area cost constraints fixed-point arithmetic fixed-point conversion fixed-point encoding decisions floating-point conversion graph-based representation image processing algorithms polyhedral methods power constraints scalability issues scalable source level accuracy analysis signal processing algorithms Accuracy Arrays Convolution convolutional codes Equations Kernel Mathematical model Fixed-point arithmetic Embedded systems Signal processing algorithms floating point arithmetic Fixed point image processing algorithm convolutional coding Convolution Graph theory signal processing FLOATING POINTS Mathematical Model Kernel

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Reconstruction of Constellation Labeling with convolutional Coded Data

Reconstruction of Constellation Labeling with Convolutional ...

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International Symposium on Information Theory and its Applications (ISITA)

作者： Sendrier, Nicolas Bellard, Marion INRIA Rocquencourt Paris France

ISBN: (纸本)9784885522673

We propose here an algorithm for reconstructing an unknown constellation labeling. Our method assumes that the underlying error correcting code is a convolutional code. We define the notions of linear and affine equivalence among labelings. Those notions will help us to reduce the cost of the search. We show that the search is intractable with our method as the constellation size grows. In that case we restrict the search to Gray labelings. Our algorithm adapts very well to that constraint and allows an easy reconstruction up to a constellation of 256 points.

关键词： CONSTELLATIONS Reconstructive Surgical Procedures convolutional coding encode data Reconstructions Searches Error correction codes

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On Jamming-proof Signal-Code Constructions for a Multiple Access System 14

On Jamming-proof Signal-Code Constructions for a Multiple Ac...

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XIV Int Symposium Problems Redundancy Inform Control Syst

作者： Osipov, Dmitry Russian Acad Sci Inst Informat Transmiss Problems Moscow Russia

In what follows signal-code constructions employing block and convolutional nonbinary inner codes that can perform under severe jamming are proposed. Robustness of the proposed signal-code constructions to jamming is ... 详细信息

ISBN: (纸本)9781479940509

关键词： encoding jamming signal processing convolutional nonbinary inner codes jamming proof signal code constructions multiple access system Block codes convolutional codes Decoding Jamming OFDM Redundancy Vectors jamming Multi access systems convolutional coding Block codes redundancy DEcoding Construction Specifications Orthogonal frequency division multiplexing signal processing

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Non-Uniform Spatial Coupling

Non-Uniform Spatial Coupling

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IEEE Information Theory Workshop (ITW)

作者： Jardel, Fanny Boutros, Joseph J. CEA LIST Communicating Syst Lab BC 94 F-91191 Gif Sur Yvette France Texas A&M Univ Qatar Doha 23874 Qatar

ISBN: (纸本)9781479959990

A new method for spatial coupling of low-density parity-check ensembles is proposed. The method is inspired from overlapped layered coding. Edges of local ensembles and those defining the spatial coupling are separately built. The new method allows the construction of non-uniform coupling chains with near-Shannon spatially-varying thresholds under iterative decoding. A direct application of non-uniform spatial coupling is unequal error protection of information.

关键词： iterative decoding parity check codes local ensemble edges low-density parity-check ensembles near-Shannon spatially-varying thresholds nonuniform spatial coupling chains overlapped layered coding unequal error protection Channel coding convolutional codes Couplings Equations Iterative decoding Iterative decoding parity check codes convolutional coding Channel coding error protection Couplings coupling

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Performance Analysis of LDPC Codes in the DM-OFDM System

Performance Analysis of LDPC Codes in the DM-OFDM System

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6th International Conference on Advanced Computational Intelligence (ICACI)

作者： Du, Na Gu, Pinbiao Hohai Univ Comp & Informat Engn Coll Nanjing Jiangsu Peoples R China Southeast Univ Sch Informat Sci & Engn Nanjing Jiangsu Peoples R China

ISBN: (纸本)9781467363433

Low density parity check code (LDPC) has constructed a flexible, low decoding complexity and performance close to Shannon limit benefits. In this paper, the method of BICM with LDPC code as its component code is applied to the Differential Modulation OFDM (DM-OFDM) system, and the comparison with the traditional method of BICM with convolutional codes (CC-BICM) is analyzed. The simulation results show that, in the DM-OFDM system the performance of LDPC codes is better than the convolutional codes. And as a result of the use of non-coherent detection which does not require channel estimation, the complexity of system is greatly reduced.

关键词： low density parity check codes convolutional coding noncoherent detection TRADITIONAL METHODS Simulation results channel estimation Complex systems

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Investigation of the Performance of Single Carrier Visible Light Communication Systems in Multi-Path Fading Optical Channels 28

Investigation of the Performance of Single Carrier Visible L...

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28th Signal Processing and Communications Applications Conference (SIU)

作者： Yasar, Sabiha Sinop, Hayriye Tek, Yusuf Islam Tuna, Elif Busra Karaerik, Kudret Ozen, Ali Nuh Naci Yazgan Univ Elekt Elekt Muhendisligi BOlumu HARGEM Kayseri Turkey

ISBN: (纸本)9781728172064

In this paper, the performances of single carrier visible light communication systems are analyzed in multi-path fading optical channels. Distortions in the data sent due to the multipath optical channel are corrected by linear and nonlinear channel equalizers. Computer simulations are performed to compare the equalizers with each other and to obtain the uncoded and encoded bit error rate performances. As a result of the simulation results, it was observed that the convolutional coded and Turbo coded system eliminates the error floor at each iteration.

关键词： visible light communication multipath optical channel channel equalizer convolutional coding Turbo coding

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