检索结果-内蒙古大学图书馆

Are sparse-coding simple cell receptive field models physiologically plausible?

Journal of Integrative Neuroscience 2006年第3期5卷 333-353页

作者： Watters, Paula Department of Computing Macquarie University Sydney NSW 2109 Australia

Olshausen and Field (1996) developed a simple cell receptive field model for natural scene processing in V1, based on unsupervised learning and non-orthogonal basis function optimization of an overcomplete representation of visual space. The model was originally tested with an ensemble of whitened natural scenes, simulating pre-cortical filtering in the retinal ganglia and lateral geniculate nucleus, and the basis functions qualitatively resembled the orientation-specific responses of V1 simple cells in the spatial domain. In this study, the quantitative tuning responses of the basis functions in the spectral domain are estimated using a Gaussian model, to determine their goodness-of-fit to the known bandwidths of simple cells in primate V1. Five simulation experiments which examined key features of the model are reported: changing the size of the basis functions;using a complete versus over-complete representation;changing the sparseness factor;using a variable learning rate;and mapping the basis functions with a whitening spatial function. The key finding of this study is that across all image themes, basis function sizes, number of basis functions, sparseness factors and learning rates, the spatial-frequency tuning did not closely resemble that of primate area 17 - the model results more closely resembled the unclassified cat neurones of area 19 with a single exception, and not area 17 as predicted. © 2006 Imperial College Press.

关键词： Basis functions Natural scenes Simple cells sparse coding

来源：评论

学校读者我要写书评

暂无评论

DASHER: A PEER-TO-PEER CONTENT DISTRIBUTION SYSTEM BASED ON COMBINED NETWORK coding

DASHER: A PEER-TO-PEER CONTENT DISTRIBUTION SYSTEM BASED ON ...

引用

2nd IEEE International Conference on Broadband Network and Multimedia Technology

作者： Ou Kaiqian Xu Yinlong Ma Guanjun Zhu Yulin Univ Sci & Technol China Dept Comp Sci & Technol Key Lab High Performance Comp Hefei Anhui Peoples R China

ISBN: (纸本)9781424450053

Network coding can ease the block scheduling and thus makes the distribution more efficient. However, the complexities of encoding and decoding increase sharply as the content size scales up. In this paper, we propose a coding scheme which combines chunked coding and sparse linear network coding to reduce both encoding and decoding costs of content distribution. Based on the combined scheme, we implement a P2P content distribution system, named Dasher, where Local-Rarest-First scheme is adopted for chunk scheduling. Under the same system architecture, we implement three comparative systems, a BitTorrent-like system, named Mybt, a system only with sparse coding, named sparser and a system using chunked coding, named Chunker. We conduct extensive experiments to compare the performance among these four systems. The experimental results show that Dasher with certain chunk sizes can reduce the average downloading time up to 15% compared with Mybt, and up to 43% with Chunker. With proper chunk sizes, the downloading time of Dasher is almost the same with sparser. The average decoding rate of Dasher is the same with Chunker, and is nearly m times as fast as sparser, where m is the number of chunks. Moreover, with respect to robustness, Dasher performs almost as well as Chunker, better than Mybt, but worse than sparser.

关键词： Network coding sparse coding Chunked coding P2P content distribution

来源：评论

学校读者我要写书评

暂无评论

Prediction of O-linked Glycosylation Sites in Protein Sequence by PCA-LDA

Prediction of O-linked Glycosylation Sites in Protein Sequen...

引用

2009 Ninth International Conference on Hybrid Intelligent Systems(第九届混合智能系统国际会议 HIS 2009)

作者： Xue-mei Yang College of Mathematics and Information Science Xianyang Normal Univ. Xianyang 712000China

O-glycosylation is one of the main types of the mammalian protein glycosylation, it occurs on the particular site of serine and threonine. In this paper, a new method of PCA-LDA is used for the prediction of O-glycosylation site under all kinds of window size (5,7,9,11,21,31,41,51). The new method of PCA-LDA is the combination of PCA and LDA, we also call it hybrid discriminant analysis(HDA). The test protein sequence which is encoded by the sparse coding is projected to the one-dimensional subspace and then by calculating the Mahanalobis distance between the projection and each class center, the test protein sequence is assigned into the “nearest” class, so it can be known that whether a particular site of serine and threonine is glycosylated. The result of experiments shows that the proposed method of HDA is more effective and accurate. The prediction accuracy is about 75％-92.5％.

关键词： prediction glycosylation protein sparse coding HDA classification

来源：评论

学校读者我要写书评

暂无评论

Spatial relationship representation for visual object searching

引用

NEUROCOMPUTING 2008年第10-12期71卷 1813-1823页

作者： Miao, Jun Duan, Lijuan Qing, Laiyun Gao, Wen Chen, Xilin Yuan, Yuan Chinese Acad Sci Inst Comp Technol Key Lab Intelligent Informat Proc Digital Media Res Ctr Beijing 100080 Peoples R China Beijing Univ Technol Coll Comp Sci & Technol Beijing 100022 Peoples R China Chinese Acad Sci Grad Univ Sch Informat Sci & Engn Beijing 100049 Peoples R China Aston Univ Sch Engn & Appl Sci Birmingham B4 7ET W Midlands England Peking Univ Inst Digital Media Beijing 100080 Peoples R China

Image representation has been a key issue in vision research for many years. In order to represent various local image patterns or objects effectively, it is important to study the spatial relationship among these objects, especially for the purpose of searching the specific object among them. Psychological experiments have supported the hypothesis that humans cognize the world using visual context or object spatial relationship. How to efficiently learn and memorize such knowledge is a key issue that should be studied. This paper proposes a new type of neural network for learning and memorizing object spatial relationship by means of sparse coding. A group of comparison experiments for visual object searching between several sparse features are carried out to examine the proposed approach. The efficiency of sparse coding of the spatial relationship is analyzed and discussed. Theoretical and experimental results indicate that the newly developed neural network can well learn and memorize object spatial relationship and simultaneously the visual context learning and memorizing have certainly become a grand challenge in simulating the human vision system. (C) 2008 Elsevier B.V. All rights reserved.

关键词： sparse coding spatial relationship visual context neural network object searching

来源：评论

学校读者我要写书评

暂无评论

An adaptive stereo basis method for convolutive blind audio source separation

引用

NEUROCOMPUTING 2008年第10-12期71卷 2087-2097页

作者： Jafari, Maria G. Vincent, Emmanuel Abdallah, Samer A. Plumbley, Mark D. Davies, Mike E. Queen Mary Univ London Dept Elect Engn Ctr Digital Mus London E1 4NS England IRISA INRIA METISS Project F-35042 Rennes France Univ Edinburgh IDCOM Edinburgh EH9 3JL Midlothian Scotland Univ Edinburgh Joint Res Inst Signal & Image Proc Edinburgh EH9 3JL Midlothian Scotland

We consider the problem of convolutive blind source separation of stereo mixtures, where a pair of microphones records mixtures of sound sources that are convolved with the impulse response between each source and sensor. We propose an adaptive stereo basis (ASB) source separation method for such convolutive mixtures, using an adaptive transform basis which is learned from the stereo mixture pair. The stereo basis vector pairs of the transform are grouped according to the estimated relative delay between the left and right channels for each basis, and the sources are then extracted by projecting the transformed signal onto the subspace corresponding to each group of basis vector pairs. The performance of the proposed algorithm is compared with FD-ICA and DUET under different reverberation and noise conditions, using both objective distortion measures and formal listening tests. The results indicate that the proposed stereo coding method is competitive with both these algorithms at short and intermediate reverberation times, and offers significantly improved performance at low noise and short reverberation times. (C) 2008 Elsevier B.V. All rights reserved.

关键词： blind source separation audio source separation independent component analysis DUET algorithm adaptive basis sparse coding

来源：评论

学校读者我要写书评

暂无评论

A universal model of esthetic perception based on the sensory coding of natural stimuli

引用

SPATIAL VISION 2008年第1-2期21卷 97-117页

作者： Redies, Christoph Univ Jena Sch Med Inst Anat 1 D-07740 Jena Germany

Philosophers have pointed out that there is a close relation between the esthetics of art and the beauty of natural scenes. Supporting this similarity at the experimental level, we have recently shown that visual art and natural scenes share fractal-like, scale-invariant statistical properties. Moreover, evidence from neurophysiological experiments shows that the visual system uses an efficient (sparse) code to process optimally the statistical properties of natural stimuli. In the present work, a hypothetical model of esthetic perception is described that combines both lines of evidence. Specifically, it is proposed that an artist creates a work of art so that it induces a specific resonant state in the visual system. This resonant state is thought to be based on the adaptation of the visual system to natural scenes. The proposed model is universal and predicts that all human beings share the same general concept of esthetic judgment. The model implies that esthetic perception, like the coding of natural stimuli, depends on stimulus form rather than content, depends on higher-order statistics of the stimuli, and is non-intuitive to cognitive introspection. The model accommodates the central tenet of neuroesthetic theory that esthetic perception reflects fundamental functional properties of the nervous system.

关键词： art esthetics efficient coding sparse coding resonance

来源：评论

学校读者我要写书评

暂无评论

Multilayer Potts Perceptrons With Levenberg-Marquardt Learning

引用

IEEE TRANSACTIONS ON NEURAL NETWORKS 2008年第12期19卷 2032-2043页

作者： Wu, Jiann-Ming Natl Doug Hwa Univ Dept Appl Math Shoufeng 974 Hualien Taiwan

This paper presents learning multilayer Potts perceptrons (MLPotts) for data driven function approximation. A Potts perceptron is composed of a receptive field and a K-state transfer function that is generalized from sigmoid-like transfer functions of traditional perceptrons. An MLPotts network is organized to perform translation from a high-dimensional input to the sum of multiple postnonlinear projections, each with its own postnonlinearity realized by a weighted K-state transfer function. MLPotts networks span a function space that theoretically covers network functions of multilayer perceptrons. Compared with traditional perceptrons, weighted Potts perceptrons realize more flexible postnonlinear functions for nonlinear mappings. Numerical simulations show MLPotts learning by the Levenberg-Marquardt (LM) method significantly improves traditional supervised learning of multilayer perceptrons for data driven function approximation.

关键词： Gaussian array population encoding postnonlinear projection Potts encoding sparse coding supervised dimensionality reduction supervised learning

来源：评论

学校读者我要写书评

暂无评论

sparse gammatone signal model optimized for English speech does not match the human auditory filters

引用

BRAIN RESEARCH 2008年 1220卷 224-233页

作者： Strahl, Stefan Mertins, Alfred Carl von Ossietzky Univ Oldenburg Int Grad Sch Neurosensory Sci & Syst D-26111 Oldenburg Germany Med Univ Lubeck Inst Signal Proc D-23538 Lubeck Germany

Evidence that neurosensory systems use sparse signal representations as well as improved performance of signal processing algorithms using sparse signal models raised interest in sparse signal codingin the last years. For natural. audio signals like speech and environmental sounds, gammatone atoms have been derived as expansion functions that generate a nearly optimal sparse signal model (Smith, E., Lewicki, M., 2006. Efficient auditory coding. Nature 439, 978-982). Furthermore, gammatone functions are established models for the human auditory filters. Thus far, a practical application of a sparse gammatone signal model has been prevented by the fact that deriving the sparsest representation is, in general, computationally intractable. In this paper, we applied an accelerated version of the matching pursuit algorithm for gammatone dictionaries allowing real-time and large data set applications. We show that a sparse signal model in general has advantages in audio coding and that a sparse gammatone signal model encodes speech more efficiently in terms of sparseness than a sparse modified discrete cosine transform (MDCT) signal model. We also show that the optimal gammatone parameters derived for English speech do not match the human auditory filters, suggesting for signal processing applications to derive the parameters individually for each applied signal class instead of using psychometrically derived parameters. For brain research, it means that care should be taken with directly transferring findings of optimality for technical to biological systems. (C) 2007 Elsevier B.V. All rights reserved.

关键词： sparse coding matching pursuit gammatone efficient coding hypothesis

来源：评论

学校读者我要写书评

暂无评论

Memory formation by refinement of neural representations: The inhibition hypothesis

引用

BEHAVIOURAL BRAIN RESEARCH 2008年第1期189卷 1-8页

作者： Axmacher, Nikolai Elger, Christian E. Fell, Juergen Univ Bonn Dept Epileptol D-53105 Bonn Germany Life & Brain Ctr Acad Res D-53127 Bonn Germany

There is no reasonable doubt that the hippocampus plays an important role in memory processing. A virtually uncountable number of studies in animals and humans have revealed changes in neural activity in this structure during memory formation [Squire LR. Memory and the hippocampus: a synthesis from findings with rats, monkeys, and humans. Psychol Rev 1992;99:195-231;Squire LR, Stark CE, Clark RE. The medial temporal lobe. Annu Rev Neurosci 2004;27:279-306], and hippocampal damage reliably leads to impairments in a large number of memory tests. However, while several correlates of successful memory formation have been found in the hippocampus, it is still an open question why specific neural processes support encoding of a particular item. An answer to this question would help to resolve current debates about which memory functions are actually supported by the hippocampus, and why activity in the neural networks of the hippocampus is involved in, or even necessary for, some memory processes but not for others. In this review, we first summarize findings on the electrophysiological activity within the hippocampus during different memory processes. We try to differentiate whether the hippocampus is merely involved in these processes, or whether the hippocampus appears to be necessary for them. Based on a distinction between a more general "encoding state" and the more specific process of "content-specific memory formation", we review data on neural representations within hippocampus and neocortex. We suggest that during memory formation, the hippocampus renders neural representations more sparse by providing an inhibitory signal to the neocortex. (c) 2007 Elsevier B.V. All rights reserved.

关键词： memory formation neural representations sparse coding hippocampus intracranial EEG

来源：评论

学校读者我要写书评

暂无评论

Non-negative sparse image coder via simulated annealing and pseudo-inversion

Non-negative sparse image coder via simulated annealing and ...

引用

33rd IEEE International Conference on Acoustics, Speech and Signal Processing

作者： Pichevar, Ramin Rouat, Jean Univ Sherbrooke Dept Elect & Comp Engn Sherbrooke PQ J1K 2R1 Canada

ISBN: (纸本)9781424414833

We propose a sparse non-negative image coding based on simulated annealing and matrix pseudo-inversion. We show that sparsity and non-negativity are both important to obtain part-based coding and we also show the impact of each of them on the coding. In contrast with other approaches in the literature, our method can constrain both weights and basis vectors to generate part-based bases suitable for image recognition and fiducial point extraction. We also propose a speed-up of the algorithm by implementing a hybrid system that mixes simulated annealing and pseudo-inverse computation of matrices.

关键词： sparse coding non-negative matrix decomposition image recognition neural networks simulated annealing

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：