形态学联想记忆网络记忆性能的定性分析

形态学联想记忆网络基于其前向映射式的网络结构特点,不管有多少个模式对,都可以用一个存储矩阵来进行存储。记忆单个模式对时,该模式对的矩阵信息完全存储在存储矩阵中,所以可以从该模式对的输入模式正确联想出输出模式,但当网络记忆了多个模式对时,各个模式对之间的相互影响就不可避免地存在,在此对其记忆性能进行定性分析,以期对MAM的研究有所裨益。     

一种新的双向联想记忆的学习算法

提出了一种新的用于双向联想记忆的学习算法，该算法利用了输入向量各元素之间的关联信息，在联想的过程中，动态地调整权值矩阵，增强了网络适应能力，利用了更多的已知信息，从而提高了网络的性能．     

一种新的形态学联想记忆网络模型研究

针对即使在输入模式无噪声,形态学联想记忆在用于异联想时仍不能保证完全回忆的问题,从扩大记忆矩阵的存储空间的角度入手,提出一种新的形态学联想记忆模型——三维存储矩阵的形态学联想记忆来刻画MAM(Morphological Associative Memories)的记忆性能。该模型能够弥补传统形态学联想记忆的记忆矩阵的不足,解决MAM在异联想时不能保证对模式对集实现完全回忆的问题。详细阐述了构建三维存储矩阵的原理与步骤,并通过实例验证三维存储矩阵的形态学联想记忆的记忆性能远远优于传统的形态学联想记忆。     

模糊联想记忆网络的增强学习算法

针对 Kosko提出的最大最小模糊联想记忆网络存在的问题 ,通过对这种网络连接权学习规则的改进 ,给出了另一种权重学习规则 ,即把 Kosko的前馈模糊联想记忆模型发展成为模糊双向联想记忆模型 ,并由此给出了模糊快速增强学习算法 ,该算法能存储任意给定的多值训练模式对集 .其中对于存储二值模式对集 ,由于其连接权值取值 0或 1,因而该算法易于硬件电路和光学实现 .实验结果表明 ,模糊快速增强学习算法是行之有效的 .     

一种基于MRⅡ算法的三层二值双向联想记忆网络

传统的两层二值双向联想记忆(BAM)网络因其结构的限制存在着存储容量有限、区分小差别模式和存储非正交模式能力不足的缺陷,结构上将其扩展至三层网络是一个有效的解决思路,但是三层二值BAM网络的学习是一个难题,而三层连续型BAM网络又存在处理二值问题不方便的问题。为了解决这些问题,提出一种三层结构的二值双向联想记忆网络,创新之处是采用了二值多层前向网络的MRⅡ算法实现了三层二值BAM网络的学习。实验结果表明,基于MRⅡ算法的三层二值BAM网络极大地提高了网络的存储容量和模式区分能力,同时保留了二值网络特定的优势,具有较高的理论与实用价值。     

形态学联想记忆存储性能的研究

形态学联想记忆（Morphological Associative Memories,MAM）的存储性能是衡量形态学联想记忆能力大小的重要指标。然而,迄今为止,对形态学联想记忆的存储性能,主要是对异联想形态学联想记忆（hetero-MAM）的存储性能的定量分析和定性刻画并未完成。这是一个悬而未决的理论问题,也是一个MAM应用的实际问题。针对这一问题开展研究,站在概率论的角度,提出一个MAM存储性能的概率模型,并进行了证明。通过定量分析和定性讨论,取得一致结论。研究和分析表明,hetero-MAM的存储性能受到输入模式向量维数n、输出模式向量维数m、以及输入、输出模式对数目K的影响,且三者的影响程度不同。提出的概率模型,对形态学联想记忆的研究、分析、设计和应用,具有一定的启发和帮助。     

一种新的双向联想记忆神经网络学习算法

文章提出了一种基于遗传算法的按`位'加权双向联想记忆神经网络(BAM)的学习算法.根据判定BAM网络稳定模式和容错能力的充分条件,推出了求取按位加权BAM加权系数的优化目标函数,之后作者给出了求解此目标函数的遗传算法.二值图象模式存储、联想记忆的计算机实验结果表明,文中所提出的方法能有效地提高网络的存储能力和容错能力.     

基于三角模的模糊双向联想记忆网络的性质研究

基于模糊取大算子和三角模T的模糊合成,构建了一类模糊双向自联想记忆网络Max-T FBAM.利用三角模T的伴随蕴涵算子,为这类Max-T FBAM提出了学习算法,并理论上证明了该学习算法确定的连接权矩阵是网络最大的连接权矩阵.对任意输入能使Max-T FBAM迭代一步内就进入稳定态,该类网络具有全局稳定性和可靠的存储能力.当三角模T满足利普希兹条件时,采用上述学习算法时自联想Max-T FBAM对训练模式的摄动全局拥有好的鲁棒性.最后用实验证实了理论研究,也为图像的可靠存储提供了参考.     

混沌在Hopfield联想记忆网络中的应用

将混沌应用到Hofield联想记忆网络中,利用混沌的遍历性和随机性等独特的性质,可以使待联想模式跳出伪模式的吸引域,而到达存储模式的吸引域内,从而解决了Hopfield网络在噪信比较高的情况下,联想成功率较低的问题。仿真结果证明了该方法的有效性。     

一种新型双向联想记忆神经网络

提出了一种新型双向联想记忆神经网络,此网络将两个相互关联的模式以模式对的形式存储在由N个连接构成的模式环中,记忆容量为22N数量级,完全消除了假模式对、能够全部或部分地回忆出与输入模式对具有最小Hamming距的被记忆的模式对,同时具有较高的记忆效率和可靠性。连接由“连接状态”和“禁止路径”组成,前者直接存储二进制模式对向量的分量,后者用于消除假模式;此神经网络具有正向联想、逆向联想和自联想方式,使得网络能更灵活有效地满足不同的回忆要求。     

Double-pattern associative memory neural network with pattern loop

A double-pattern associative memory neural network with “pattern loop” is proposed. It can store 2N bit bipolar binary patterns up to the order of 2^2N , retrieve part or all of the stored patterns which all have the minimum Hamming distance with input pattern, completely eliminate spurious patterns, and has higher storing efficiency and reliability than conventional associative memory. The length of a pattern stored in this associative memory can be easily extended from 2N to κN.     

混沌神经网络在分离叠加模式和多对多联想记忆中的应用

混沌是不含外加随机因素的完全确定性的系统表现出来的界于规则和随机之间的内秉随机行为。脑神经系统是由神经细胞组成的网络。类似于人脑思维的人工神经网络与冯·诺依曼计算机相比,在信息处理方面有很大的优越性。混沌和神经网络相互融合的研究是从90年代开始的,其主要的目标是通过分析大脑的混沌现象,建立含有混沌动力学的神经网络模型(即混沌神经网络模型),将混沌的遍历性、对初始值敏感等特点与神经网络的非线性、自适应、并行处理优势相结合,     

Some experiments on human memory and a new neural model

An associative memory with parallel architecture is presented. The neurons are modelled by perceptrons having only binary, rather than continuous valued input. To store m elements each having n features, m neurons each with n connections are needed. The n features are coded as an n-bit binary vector. The weights of the n connections that store the n features of an element has only two values -1 and 1 corresponding to the absence or presence of a feature. This makes the learning very simple and straightforward. For an input corrupted by binary noise, the associative memory indicates the element that is closest (in terms of Hamming distance) to the noisy input. In the case where the noisy input is equidistant from two or more stored vectors, the associative memory indicates two or more elements simultaneously. From some simple experiments performed on the human memory and also on the associative memory, it can be concluded that the associative memory presented in this paper is in some respect more akin to a human memory than a Hopfield model.     

A categorizing associative memory using an adaptive classifier andsparse coding

This paper proposes a neural network that stores and retrieves sparse patterns categorically, the patterns being random realizations of a sequence of biased (0,1) Bernoulli trials. The neural network, denoted as categorizing associative memory, consists of two modules: 1) an adaptive classifier (AC) module that categorizes input data; and 2) an associative memory (AM) module that stores input patterns in each category according to a Hebbian learning rule, after the AC module has stabilized its learning of that category. We show that during training of the AC module, the weights in the AC module belonging to a category converge to the probability of a “1” occurring in a pattern from that category. This fact is used to set the thresholds of the AM module optimally without requiring any a priori knowledge about the stored patterns     

Fuzzy Associative Conjuncted Maps Network

The fuzzy associative conjuncted maps (FASCOM) is a fuzzy neural network that associates data of nonlinearly related inputs and outputs. In the network, each input or output dimension is represented by a feature map that is partitioned into fuzzy or crisp sets. These fuzzy sets are then conjuncted to form antecedents and consequences, which are subsequently associated to form if–then rules. The associative memory is encoded through an offline batch mode learning process consisting of three consecutive phases. The initial unsupervised membership function initialization phase takes inspiration from the organization of sensory maps in our brains by allocating membership functions based on uniform information density. Next, supervised Hebbian learning encodes synaptic weights between input and output nodes. Finally, a supervised error reduction phase fine-tunes the network, which allows for the discovery of the varying levels of influence of each input dimension across an output feature space in the encoded memory. In the series of experiments, we show that each phase in the learning process contributes significantly to the final accuracy of prediction. Further experiments using both toy problems and real-world data demonstrate significant superiority in terms of accuracy of nonlinear estimation when benchmarked against other prominent architectures and exhibit the network's suitability to perform analysis and prediction on real-world applications, such as traffic density prediction as shown in this paper.      

CMOS current-mode neural associative memory design with on-chiplearning

Based on the Grossberg mathematical model called the outstar, a modular neural net with on-chip learning and memory is designed and analyzed. The outstar is the minimal anatomy that can interpret the classical conditioning or associative memory. It can also be served as a general-purpose pattern learning device. To realize the outstar, CMOS (complimentary metal-oxide semiconductor) current-mode analog dividers are developed to implement the special memory called the ratio-type memory. Furthermore, a CMOS current-mode analog multiplier is used to implement the correlation. The implemented CMOS outstar can on-chip store the relative ratio values of the trained weights for a long time. It can also be modularized to construct general neural nets. HSPICE (a circuit simulator of Meta Software, Inc.) simulation results of the CMOS outstar circuits as associative memory and pattern learner have successfully verified their functions. The measured results of the fabricated CMOS outstar circuits have also successfully confirmed the ratio memory and on-chip learning capability of the circuits. Furthermore, it has been shown that the storage time of the ratio memory can be as long as five minutes without refreshment. Also the outstar can enhance the contrast of the stored pattern within a long period. This makes the outstar circuits quite feasible in many applications.     

多值指数式多向联想记忆模型

多向联想记忆MDAM(multidirectional associative memory)模型是Kosko双向联想记忆模型BAM(bidirectional associative memory)的一个直接推广,它可应用于数据融合及维数分裂,使模型能处理大维数输入问题.目前所提出的若干种多向模型均局限于二值输入/输出模式对,但如在图象处理等的实际应用中,所处理的模式均是多值的.本文的目的就是提出一个多值指数式多向联想记忆模型MVeMDAM(multivalued exponential multidi     

A study of pattern recovery in recurrent correlation associative memories

In this paper, we analyze the recurrent correlation associative memory (RCAM) model of Chiueh and Goodman (1990, 1991). This is an associative memory in which stored binary memory patterns are recalled via an iterative update rule. The update of the individual pattern-bits is controlled by an excitation function, which takes as its argument the inner product between the stored memory patterns and the input patterns. Our contribution is to analyze the dynamics of pattern recall when the input patterns are corrupted by noise of a relatively unrestricted class. We show how to identify the excitation function which maximizes the separation (the Fisher discriminant) between the uncorrupted realization of the noisy input pattern and the remaining patterns residing in the memory. The excitation function which gives maximum separation is exponential when the input bit-errors follow a binomial distribution. We develop an expression for the expectation value of bit-error probability on the input pattern after one iteration. We show how to identify the excitation function which minimizes the bit-error probability. The relationship between the excitation functions which result from the two different approaches is examined for a binomial distribution of bit-errors. We develop a semiempirical approach to the modeling of the dynamics of the RCAM.     

A walsh-hadamard based distributed storage device for the associative search of information

A computer model for a distributed associative memory has been developed based on Walsh-Hadamard functions. In this memory device, the information storage is distributed over the entire memory medium and thereby lends itself to parallel comparison of the input with stored data. These inherent economic storage and parallel processing capabilities may be found effective especially in real-time processing of large amount of information. However, overlaying different pieces of data in the same memory medium creates the problem of interference or crosstalk between stored data and may lead to recognition errors. In this paper, a crosstalk reduction technique utilizing the gradient descent procedure is developed first. This minimizes the memory processing error and enhances memory saving. Second, for an efficient implementation of the memory structure, these associative memories are configured in a hierarchical structure which not only expands storage capacity but also utilizes the speed of tree search. Finally, a self-correcting technique is developed which achieves error-free recognition of near neighbors for any training pattern even among the presence of crosstalk.