检索结果-内蒙古大学图书馆

A lossless compression method for logging data while drilling

SYSTEMS SCIENCE & CONTROL ENGINEERING 2021年第1期9卷 689-703页

作者： Song, Shan Lian, Taiwei Liu, Wei Zhang, Zhengbing Luo, Mingzhang Wu, Aiping Yangtze Univ Elect Informat Sch Jingzhou Peoples R China Direct Drilling Technol Serv Co CCDC Drilling & Prod Engn Technol Res Inst Deyang Peoples R China

Mud pulse transmission technology is widely used in logging while drilling (LWD), while its low data transmission efficiency has restricted the development of LWD technology for a long time. In order to improve the equivalent data transmission efficiency of LWD system, a data compression method, namely, Frame Prediction Huffman coding (FPHC) with a group of frames, is proposed in this paper. Several factors including the data accuracy, the need for real-time transmission, and the existence of transmission errors are comprehensively considered in the proposed method. Through the probability statistical analysis of LWD data, it is proved that the data have a relatively stable probability distribution after predictive coding. In addition, the Huffman code table generated from predictive coding is universally applicable to other LWD data. Through data compression experiments on logging data, it is verified that the proposed method has higher compression efficiency compared with Huffman coding, Lempel-Ziv-Welch algorithm, adaptive Huffman coding and adaptive arithmetic coding. This lossless compression method will have a good application prospect because of its ability to prevent error diffusion, simple implementation and easy to be embedded in down-hole equipment.

关键词： Logging while drilling lossless data compression predictive coding Huffman coding mud pulse

来源：评论

学校读者我要写书评

暂无评论

Simulation during observation of human actions - Theories, empirical studies, applications

引用

VISION RESEARCH 2011年第8期51卷 827-835页

作者： Zentgraf, Karen Munzert, Joern Bischoff, Matthias Newman-Norlund, Roger D. Univ Bern Inst Sports Sci CH-3012 Bern Switzerland Univ Giessen Bender Inst Neuroimaging D-35394 Giessen Germany Univ Giessen Inst Sports Sci D-35394 Giessen Germany Univ S Carolina Dept Exercise Sci Columbia SC 29208 USA

Historically, data from brain imaging and brain stimulation studies have supported the idea that the processing of observed actions recruits - among other areas - a distinct sub-set of brain sites in the sensory and motor cortices. These empirical findings have initially been linked with the thesis of direct matching as a mechanism of action understanding, i.e., the idea of motor resonance implemented by mirror neurons. In more recent approaches, it has been proposed that the mirror neuron system plays a role in minimizing prediction error when inferring the most likely cause of an observed action. According to these theories, motor resonance is thought to function as predictive coding. Other theoretical accounts suggest that action understanding might result from a hypothesis testing mechanism in which potential goals are continually fed into the system until the correct one is identified. In this review, we will explore the relationship of these theories to specific empirical findings. Finally, we will discuss the implications of these theoretical structures on action observation-based approaches to the optimization of skilled performance in athletes and patients. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Action observation Mirror neurons Direct matching predictive coding Action reconstruction

来源：评论

学校读者我要写书评

暂无评论

A LOW BIT-RATE IMAGE SEQUENCE CODER COMBINING A PROGRESSIVE DPCM ON INTERLEAVED RASTERS WITH A HYBRID DCT TECHNIQUE

引用

IEEE JOURNAL ON SELECTED AREAS IN COMMUNICATIONS 1987年第7期5卷 1079-1089页

作者： GERKEN, P SCHILLER, H Institut für Theoretische Nachrichtentechnik und Informationsverarbeitung University of Hannover Hanover Germany

An image sequence coding scheme for transmission at 384 kbits/s and 64 kbits/s is presented. In comparison to known schemes, picture quality in still picture areas is improved without impairing the rendition of temporally changed areas. Bit-rate reduction is obtained by a conventional hybrid DCT coding technique in changed areas, and a predictive coding technique using a raster interleaving approach to update still picture areas. Preferentially treating the image signal in still areas with a not-block-oriented coder yields in these regions a reconstruction with full spatial resolution and free of any block effects. Experimental results are presented confirming that the quality in still picture areas is improved compared to that of known low bit-rate image sequence coding schemes, while the quality in changed areas is maintained.

关键词： Image sequences Discrete cosine transforms Interleaved codes Spatial resolution Bit rate Image coding predictive coding Teleconferencing Degradation Layout

来源：评论

学校读者我要写书评

暂无评论

A neural network model for exogenous perceptual alternations of the Necker cube

引用

COGNITIVE NEURODYNAMICS 2020年第2期14卷 229-237页

作者： Araki, Osamu Tsuruoka, Yuki Urakawa, Tomokazu Tokyo Univ Sci Dept Appl Phys Tokyo Japan

When a bistable visual image, such as the Necker cube, is continuously viewed, the percept of the image endogenously alternates between one possible percept and the other. However, perceptual alternation can also be induced by an exogenous perturbation. For example, a typical external perturbation is the flashlight, which is expected to pervasively activate many brain regions. Therefore, the neural mechanism related to exogenous perceptual alternation remains to be clarified. As a cue to solving this problem, our recent psychophysiological experiment reported a positive correlation between the enhancement of visual mismatch negativity evoked by breaks in the sequential regularity of the visual stimuli and the proportion of perceptual alternation. To elucidate the mechanism underlying exogenous perceptual alternation induced by visual mismatch negativity, the present study attempted to construct a neural network model for bistable perception of the Necker cube, whose perceptual alternation is facilitated by an increase in visual mismatch negativity. The model consists of both a prediction layer and a prediction error layer, following the predictive coding framework for biologically plausible relationships between the change detection process and the perceptual alternation mechanism. Computer simulations showed that the mean duration of perception decreased as the response increased, which is in concordance with the experimental data. This result suggested that the excitatory feedforward and inhibitory feedback connections play an important role. Additionally, the validity of this model suggests that the visual mismatch signal propagates in the neural systems and affects the visual perceptual mechanism as a prediction error signal.

关键词： Necker cube Perceptual alternation Neural network model predictive coding

来源：评论

学校读者我要写书评

暂无评论

Magic, Bayes and wows: A Bayesian account of magic tricks

引用

NEUROSCIENCE AND BIOBEHAVIORAL REVIEWS 2021年 126卷 515-527页

作者： Grassi, Pablo Rodrigo Bartels, Andreas Univ Tubingen Dept Psychol Schleichtstr 4 D-72076 Tubingen Germany Ctr Integrat Neurosci Otfried Mullerstr 25 D-72075 Tubingen Germany Max Planck Inst Biol Cybernet Tubingen Germany

Magic tricks have enjoyed an increasing interest by scientists. However, most research in magic focused on isolated aspects of it and a conceptual understanding of magic, encompassing its distinct components and varieties, is missing. Here, we present an account of magic within the theory of Bayesian predictive coding. We present the "wow" effect of magic as an increase in surprise evoked by the prediction error between expected and observed data. We take into account prior knowledge of the observer, attention, and (mis-)direction of perception and beliefs by the magician to bias the observer's predictions and present a simple example for the modelling of the evoked surprise. The role of misdirection is described as everything that aims to maximize the surprise a trick evokes by the generation of novel beliefs, the exploitation of background knowledge and attentional control of the incoming information. Understanding magic within Bayesian predictive coding allows unifying all aspects of magic tricks within one framework, making it tractable, comparable and unifiable with other models in psychology and neuroscience.

关键词： Magic Bayesian surprise predictive coding Misdirection Attention

来源：评论

学校读者我要写书评

暂无评论

Cortical Layer-Dependent Signaling in Cognition: Three Computational Modes of the Canonical Circuit

引用

ANNUAL REVIEW OF NEUROSCIENCE 2024年第1期47卷 211-234页

作者： Miyashita, Yasushi Univ Tokyo Dept Physiol Sch Med Tokyo Japan Juntendo Univ Grad Sch Med Tokyo Japan

The cerebral cortex performs computations via numerous six-layer modules. The operational dynamics of these modules were studied primarily in early sensory cortices using bottom-up computation for response selectivity as a model, which has been recently revolutionized by genetic approaches in mice. However, cognitive processes such as recall and imagery require top-down generative computation. The question of whether the layered module operates similarly in top-down generative processing as in bottom-up sensory processing has become testable by advances in the layer identification of recorded neurons in behaving monkeys. This review examines recent advances in laminar signaling in these two computations, using predictive coding computation as a common reference, and shows that each of these computations recruits distinct laminar circuits, particularly in layer 5, depending on the cognitive demands. These findings highlight many open questions, including how different interareal feedback pathways, originating from and terminating at different layers, convey distinct functional signals.

关键词： six-layer organization bottom-up feedforward computation top-down generative computation predictive coding dynamic signal routing retrieval in deep layers

来源：评论

学校读者我要写书评

暂无评论

Feature-specific prediction errors for visual mismatch

引用

NEUROIMAGE 2019年 196卷 142-151页

作者： Stefanics, Gabor Stephan, Klaas Enno Heinzle, Jakob Univ Zurich Inst Biomed Engn TNU Wilfriedstr 6 CH-8032 Zurich Switzerland Swiss Fed Inst Technol Wilfriedstr 6 CH-8032 Zurich Switzerland Univ Zurich Dept Econ Lab Social & Neural Syst Res Blumlisalpstr 10 CH-8006 Zurich Switzerland Max Planck Inst Metab Res Cologne Germany

predictive coding (PC) theory posits that our brain employs a predictive model of the environment to infer the causes of its sensory inputs. A fundamental but untested prediction of this theory is that the same stimulus should elicit distinct precision weighted prediction errors (pwPEs) when different (feature-specific) predictions are violated, even in the absence of attention. Here, we tested this hypothesis using functional magnetic resonance imaging (fMRI) and a multi-feature roving visual mismatch paradigm where rare changes in either color (red, green), or emotional expression (happy, fearful) of faces elicited pwPE responses in human participants. Using a computational model of learning and inference, we simulated pwPE and prediction trajectories of a Bayes-optimal observer and used these to analyze changes in blood oxygen level dependent (BOLD) responses to changes in color and emotional expression of faces while participants engaged in a distractor task. Controlling for visual attention by eye-tracking, we found pwPE responses to unexpected color changes in the fusiform gyrus. Conversely, unexpected changes of facial emotions elicited pwPE responses in cortico-thalamo-cerebellar structures associated with emotion and theory of mind processing. Predictions pertaining to emotions activated fusiform, occipital and temporal areas. Our results are consistent with a general role of PC across perception, from low-level to complex and socially relevant object features, and suggest that monitoring of the social environment occurs continuously and automatically, even in the absence of attention.

关键词： predictive coding Precision weighted prediction error Color perception Emotion recognition Perception Perceptual inference

来源：评论

学校读者我要写书评

暂无评论

Probing top-down information in neocortical layer 1

引用

TRENDS IN NEUROSCIENCES 2023年第1期46卷 20-31页

作者： Pardi, M. Belen Schroeder, Anna Letzkus, Johannes J. Univ Freiburg Inst Physiol Fac Med D-79108 Freiburg Germany Univ Paris Cite Inst Psychiat & Neurosci Paris IPNP INSERM U1266 F-75014 Paris France Max Planck Inst Brain Res D-60438 Frankfurt Germany Univ Freiburg Ctr Basics NeuroModulat NeuroModul Basics D-79106 Freiburg Germany Univ Freiburg IMBIT BrainLinks BrainTools D-79110 Freiburg Germany

Accurate perception of the environment is a constructive process that requires inte-gration of external bottom-up sensory signals with internally generated top-down information. Decades of work have elucidated how sensory neocortex processes physical stimulus features. By contrast, examining how top-down information is encoded and integrated with bottom-up signals has been challenging using tradi-tional neuroscience methods. Recent technological advances in functional imaging of brain-wide afferents in behaving mice have enabled the direct measurement of top-down information. Here, we review the emerging literature on encoding of these internally generated signals by different projection systems enriched in neo-cortical layer 1 during defined brain functions, including memory, attention, and pre-dictive coding. Moreover, we identify gaps in current knowledge and highlight future directions for this rapidly advancing field.

关键词： sensory neocortex memory attention predictive coding axonal imaging L1

来源：评论

学校读者我要写书评

暂无评论

Encoding of Stimulus Probability in Macaque Inferior Temporal Cortex

引用

CURRENT BIOLOGY 2016年第17期26卷 2280-2290页

作者： Bell, Andrew H. Summerfield, Christopher Morin, Elyse L. Malecek, Nicholas J. Ungerleider, Leslie G. NIMH Lab Brain & Cognit 9000 Rockville Pike Bethesda MD 20892 USA Univ Oxford Dept Expt Psychol S Parks Rd Oxford OX1 3UD England MRC Cognit & Brain Sci Unit 15 Chaucer Rd Cambridge CB2 7EF England

Optimal perceptual decisions require sensory signals to be combined with prior information about stimulus probability. Although several theories propose that probabilistic information about stimulus occurrence is encoded in sensory cortex, evidence from neuronal recordings has not yet fully supported this view. We recorded activity from single neurons in inferior temporal cortex (IT) while monkeys performed a task that involved discriminating degraded images of faces and fruit. The relative probability of the cue being a face versus a fruit was manipulated by a latent variable that was not revealed to the monkeys and that changed unpredictably over the course of each recording session. In addition to responding to stimulus identity (face or fruit), population responses in IT encoded the long-term stimulus probability of whether a face or a fruit stimulus was more likely to occur. Face-responsive neurons showed reduced firing rates to expected faces, an effect consistent with "expectation suppression," but expected stimuli were decoded from multivariate population signals with greater accuracy. These findings support "predictive coding" theories, whereby neural signals in the mammalian visual system actively encode and update predictions about the local sensory environment.

关键词： decision making expectation suppression monkey neuron predictive coding

来源：评论

学校读者我要写书评

暂无评论

Attentional Enhancement of Auditory Mismatch Responses: a DCM/MEG Study

引用

CEREBRAL CORTEX 2015年第11期25卷 4273-4283页

作者： Auksztulewicz, Ryszard Friston, Karl UCL Inst Neurol Wellcome Trust Ctr Neuroimaging London WC1N 3BG England

Despite similar behavioral effects, attention and expectation influence evoked responses differently: Attention typically enhances event-related responses, whereas expectation reduces them. This dissociation has been reconciled under predictive coding, where prediction errors are weighted by precision associated with attentional modulation. Here, we tested the predictive coding account of attention and expectation using magnetoencephalography and modeling. Temporal attention and sensory expectation were orthogonally manipulated in an auditory mismatch paradigm, revealing opposing effects on evoked response amplitude. Mismatch negativity (MMN) was enhanced by attention, speaking against its supposedly pre-attentive nature. This interaction effect was modeled in a canonical microcircuit using dynamic causal modeling, comparing models with modulation of extrinsic and intrinsic connectivity at different levels of the auditory hierarchy. While MMN was explained by recursive interplay of sensory predictions and prediction errors, attention was linked to the gain of inhibitory interneurons, consistent with its modulation of sensory precision.

关键词： attention dynamic causal modeling expectation magnetoencephalography predictive coding

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：