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IEEE International Symposium on Geoscience and Remote Sensing (IGARSS)

作者： M. Remus K. Sayood Dept. of Electr. Eng. Nebraska Univ. Lincoln NE USA Department of Electrical Engineering University of Nebraska Lincoln USA

Addresses the problem of accessing portions of multiband data which has been losslessly compressed. An approach that uses the fractal property of some well known space filling curves to provide access to portions of a losslessly compressed data set is described. This approach reduces the average amount of decompression necessary to access any portion of the data set, thereby reducing the amount of time required to access the compressed data. Various tradeoffs exist which will be discussed with practical examples.< >

关键词： Encoding Decoding Partitioning algorithms Testing predictive coding Books Filling Dictionaries Libraries Information retrieval

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Local adaptive learning and fusion for side information interpolation in distributed video coding

Local adaptive learning and fusion for side information inte...

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Picture coding Symposium, PCS

作者： Xianming Liu Yongbing Zhang Yongpeng Li Hongbin Liu Siwei Ma Debin Zhao Department of Computer Science and Technology Harbin Institute of Technology Harbin China Chinese Academy of Sciences Beijing China Institute of Digital Media Peking University Beijing China

Motivated by theoretical analysis of the curve fitting problem based on equivalent kernel, in this paper we propose a local adaptive learning and fusion model for side information interpolation in distributed video coding. In the proposed model, each pixel in the interpolated frame is approximated as the linear combination of samples within a local spatio-temporal window using kernel parameters as weight. The size of training window can be adaptive to the motion characteristic of video, from samples in which the kernel parameters can be locally learned. In order to further improve the quality of interpolated frames, we introduce a belief-projection based fusion strategy with adaptive weights for multiple interpolated results which are with the same time index. Experimental results demonstrate that the proposed learning and fusion model is effective in performance for side information interpolation in distributed video coding.

关键词： Interpolation Video coding Kernel Decoding Curve fitting Motion analysis Motion estimation Fusion power generation predictive coding Encoding

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A new three level predictive technique for lossy data compression

A new three level predictive technique for lossy data compre...

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IEEE International Conference on Industrial Technology (ICIT)

作者： Radhakrishnan Swaminathan Manohar Das Department of Electrical and Computer Engineering Okland University Rochester MI USA

A new hybrid predictive coding scheme for lossy data compression is introduced and studied here. The proposed technique attempts to improve the compression performance of a conventional adaptive predictive coder through three levels of prediction. The first level estimates and removes a time-varying mean signal. The second level uses DFT and IDFT to estimate and remove the predictable high frequency subband component of the signal, whereas the third level performs the adaptive predictive coding of the smoothed signal. The resultant residual is then quantized using an adaptive quantizer with 3 and 5 levels. Experimental results based on a group of test signals seem to indicate that the proposed hybrid scheme can improve the lossy compression achievable using a conventional adaptive predictive coder.

关键词： predictive models Signal to noise ratio predictive coding Adaptation model Data compression Discrete Fourier transforms Receivers

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Analysis, synthesis and perception of the French nasal vowels

Analysis, synthesis and perception of the French nasal vowel...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： E. Bognar H. Fujisaki Faculty of Engineering University of Tokyo Tokyo Japan

The purpose of the research reported here was to find out some acoustical and perceptual characteristics of the French nasal vowels. Acoustic analysis was made using a Pole-Zero Analysis-by-Synthesis procedure : below 4 kHz (in the case of male adult informants) the main acoustic correlates of the nasal vowels are the formant shifts and the introduction of two pole-zero pairs, one below F1, the other between F2 and F3. By means of a pole-zero synthesizer, synthetic stimuli were generated : two of them have the spectral characteristics of the real vowels [ \varepsilon ] and [ \tilde{\varepsilon} ], while the others are stimuli whose spectral characteristics are between those of [ \varepsilon ] and [ \tilde{\varepsilon} ]. Phonemic and phonetic perceptual tests were conducted. Their results show that formant shifts and pole-zero separation contribute almost equally to the decision on the phonemic identity of / \varepsilon / versus / \tilde{\varepsilon} /, whereas pole-zero separation has a stronger effect than formant shifts in the phonetic judgment on nasality.

关键词： Loudspeakers Speech analysis Acoustic testing Bandwidth Speech recognition predictive coding Frequency synthesizers Transfer functions Speech synthesis Analog-digital conversion

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Techniques for improving the robustness of an adaptive predictive coder in the presence of channel errors

Techniques for improving the robustness of an adaptive predi...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： E. Singer M.I.T. Lincoln Laboratory Lexington Masssachusetts

A study was performed to evaluate various techniques for improving the robustness of an Adaptive predictive Coder operating in the presence of channel errors. The communications environment consisted of a packetized, symbol oriented system in which channel errors were manifested as both 5-bit symbol errors in the received bit stream and the occasional loss of an entire packet of data. To reduce the effects of symbol errors forward error correction was applied to a selected subset of the transmitted parameter bits. At the receiver, smoothing strategies were employed to replace those parameters in which errors could be detected but not corrected and to cope with situations in which entire packets were lost. The introduction of these techniques to the basic APC vocoder added 900-1100 bps to the bit rate and resulted in significantly improved robustness in channel errors.

关键词： Robustness Speech synthesis Bit rate Error correction Acoustic distortion Speech analysis Forward error correction Smoothing methods Vocoders predictive coding

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MODELS OF SELF IN SELF-KNOWLEDGE

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FILOZOFIA NAUKI 2019年第3期27卷 55-76页

作者： Pacholik-Zuromska, Anita Uniwersytet Mikol Kopernika Toruniu Katedra Kognitywistyki Wydzial Humanisty Ul Fosa Staromiejska 1a PL-87100 Torun Poland

This article argues for an externalist self-model in self-knowledge, as an answer to the question of how to defend self-knowledge in the face of evident errors in self-cognition such as self-illusions. The externalist model is contrasted with an internalist model, although both are based on a predictive coding mechanism. The main thesis is that for preserving the status of self-knowledge as knowledge an external element is needed - namely, some feedback from the environment - which corrects not only cognitive prediction errors regarding the world but also errors in self-cognition by forcing the proper action of the subject (agent) and dynamic adaptation of the model of the embodied self. The mechanism of self-corrections is best described by externalist models.

关键词： self-knowledge self predictive coding externalism internalism enactivism cybernetics

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Extending Gurwitsch's field theory of consciousness

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CONSCIOUSNESS AND COGNITION 2015年 34卷 104-123页

作者： Yoshimi, Jeff Vinson, David W. Univ Calif Merced Cognit & Informat Sci Merced CA 95343 USA

Aron Gurwitsch's theory of the structure and dynamics of consciousness has much to offer contemporary theorizing about consciousness and its basis in the embodied brain. On Gurwitsch's account, as we develop it, the field of consciousness has a variable sized focus or "theme" of attention surrounded by a structured periphery of inattentional contents. As the field evolves, its contents change their status, sometimes smoothly, sometimes abruptly. Inner thoughts, a sense of one's body, and the physical environment are dominant field contents. These ideas can be linked with (and help unify) contemporary theories about the neural correlates of consciousness, inattention, the small world structure of the brain, meta-stable dynamics, embodied cognition, and predictive coding in the brain. Published by Elsevier Inc.

关键词： Gurwitsch Attention Inattention Phenomenology Neural correlates of consciousness Embodied cognition Global neuronal workspace Small world networks Meta-stable dynamics predictive coding

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Order of statistical learning depends on perceptive uncertainty

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Current Research in Neurobiology 2023年 4卷 100080页

作者： Daikoku, Tatsuya Yumoto, Masato International Research Center for Neurointelligence The University of Tokyo 7-3-1 Hongo Bunkyo-ku Tokyo Japan Center for Brain Mind and KANSEI Sciences Research Hiroshima University Hiroshima Japan

Statistical learning (SL) is an innate mechanism by which the brain automatically encodes the n-th order transition probability (TP) of a sequence and grasps the uncertainty of the TP distribution. Through SL, the brain predicts a subsequent event (e_n+1) based on the preceding events (e_n) that have a length of “n”. It is now known that uncertainty modulates prediction in top-down processing by the human predictive brain. However, the manner in which the human brain modulates the order of SL strategies based on the degree of uncertainty remains an open question. The present study examined how uncertainty modulates the neural effects of SL and whether differences in uncertainty alter the order of SL strategies. It used auditory sequences in which the uncertainty of sequential information is manipulated based on the conditional entropy. Three sequences with different TP ratios of 90:10, 80:20, and 67:33 were prepared as low-, intermediate, and high-uncertainty sequences, respectively (conditional entropy: 0.47, 0.72, and 0.92 bit, respectively). Neural responses were recorded when the participants listened to the three sequences. The results showed that stimuli with lower TPs elicited a stronger neural response than those with higher TPs, as demonstrated by a number of previous studies. Furthermore, we found that participants adopted higher-order SL strategies in the high uncertainty sequence. These results may indicate that the human brain has an ability to flexibly alter the order based on the uncertainty. This uncertainty may be an important factor that determines the order of SL strategies. Particularly, considering that a higher-order SL strategy mathematically allows the reduction of uncertainty in information, we assumed that the brain may take higher-order SL strategies when encountering high uncertain information in order to reduce the uncertainty. The present study may shed new light on understanding individual differences in SL performa

关键词： entropy Information theory Markovian N-gram predictive coding

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Dual counterstream architecture may support separation between vision and predictions

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CONSCIOUSNESS AND COGNITION 2022年 103卷 103375页

作者： Maric, Mateja Domijan, Drazen Univ Rijeka Rijeka Croatia

According to a predictive coding framework, visual processing involves the computation of prediction errors between sensory data and a generative model that is supplied via feedback projections. This implies that vision is cognitively penetrable by all sorts of top-down influences. In this paper, we review anatomical and functional data which suggest that feedforward and feedback projections are organized into two parallel processing streams: the supragranular and the infragranular counterstreams. The supragranular counterstream computes surface and motion representation in depth. It represents the best interpretation of what is given in the input image based on physical regularities that are built into this network. By contrast, the infragranular counterstream integrates vision with cognition, because it represents what is likely to be found in the environment based on the predictions derived from learned statistical regularities. The two counterstreams work in parallel, but independently of each other. They compete for dominance, and only one is allowed to deliver its output to higher-order areas at any instance of time. Such an arrangement allows the supragranular counterstream to remain cognitively impenetrable to top-down influences.

关键词： Attention Cognitive penetrability of vision Context Counterstreams Feedback projections predictive coding

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Generative models, brain function and neuroimaging

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SCANDINAVIAN JOURNAL OF PSYCHOLOGY 2001年第3期42卷 167-177页

作者： Friston, KJ Price, CJ Inst Neurol Wellcome Dept Cognit Neurol London WC1N 3BG England

The representational capacity and inherent function of any neuron, neuronal population or cortical area in the brain is dynamic and context-sensitive. Functional integration, or interactions among brain systems, that employ driving (bottom up) and backward (top-down) connections, mediate this adaptive and contextual specialisation. A critical consequence is that neuronal responses, in any given cortical area, can represent different things at different times. This can have fundamental implications for the design of brain imaging experiments and the interpretation of their results. Our arguments are developed under generative models of brain function, where higher-level systems provide a prediction of the inputs to lower-level regions. Conflict between the two is resolved by changes in the higher-level representations, which are driven by the ensuing error in lower regions, until the mismatch is "cancelled". From this perspective the specialisation of any region is determined both by bottom-up driving inputs and by top-down predictions. Specialisation is therefore not an intrinsic property of any region but depends on both forward and backward connections with other areas. Because the latter have access to the context in which the inputs are generated they are in a position to modulate the selectivity or specialisation of lower areas. The implications for classical models (e.g., classical receptive fields in electrophysiology, classical specialisation in neuroimaging and connectionism in cognitive models) are severe and suggest these models may provide incomplete accounts of real brain architectures. Here we focus on the implications for cognitive neuroscience in the context of neuroimaging.

关键词： functional specialisation functional integration generative models predictive coding dynamic diaschisis

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