Adaptive competitive self-organizing associative memory

This work presents the design of an adaptive competitive self-organizing associative memory (ACSAM) system for use in classification and recognition of pattern information. Volterra and Lotka's models of interacting species in biology motivated the ACSAM model; a model based on a system of nonlinear ordinary differential equations (ODEs). Self-organizing behavior is modeled for unsupervised neural networks employing the concept of interacting/competing species in biology. In this model, self-organizing properties can be implicitly coded within the systems trajectory structure using only ODEs. Among the features of this continuous-time system are: 1) the dynamic behavior is well-understood and characterized; 2) the desired fixed points are the only asymptotically stable states of the system; 3) the trajectories of ACSAM derived from the weight activities of the gradient system have no periodic or homoclinic orbits; and 4) the heteroclinic orbits that exist between equilibrium states are structurally unstable and can be removed by small perturbations.     

Neural associative memory with optimal Bayesian learning

Neural associative memories are perceptron-like single-layer networks with fast synaptic learning typically storing discrete associations between pairs of neural activity patterns. Previous work optimized the memory capacity for various models of synaptic learning: linear Hopfield-type rules, the Willshaw model employing binary synapses, or the BCPNN rule of Lansner and Ekeberg, for example. Here I show that all of these previous models are limit cases of a general optimal model where synaptic learning is determined by probabilistic Bayesian considerations. Asymptotically, for large networks and very sparse neuron activity, the Bayesian model becomes identical to an inhibitory implementation of the Willshaw and BCPNN-type models. For less sparse patterns, the Bayesian model becomes identical to Hopfield-type networks employing the covariance rule. For intermediate sparseness or finite networks, the optimal Bayesian learning rule differs from the previous models and can significantly improve memory performance. I also provide a unified analytical framework to determine memory capacity at a given output noise level that links approaches based on mutual information, Hamming distance, and signal-to-noise ratio.     

加强学习与联想记忆的粒子群优化算法

为了克服粒子群优化算法多维搜索时方向性差、目的性弱以及易早熟收敛等缺点,提出了一种改进的粒子群优化算法。改进的算法分别对认知部分及社会部分的最优信息、最差信息赋予不同的学习因子,使算法具有更强的学习能力。每个粒子联想记忆其历史最优、最差信息,然后按照追逐最优躲避最差的原则寻找最优位置。联想记忆克服了多维搜索中方向性差、目的性弱的缺点;追优避差保持了种群的多样性,有利于提高算法的收敛速度、克服早熟收敛。通过基准函数的仿真测实验证了算法的有效性。     

Evolving neural networks with iterative learning scheme for associative memory

A locally iterative learning (LIL) rule is adapted to a model of the associative memory based on the evolving recurrent-type neural networks composed of growing neurons. There exist extremely different scale parameters of time, the individual learning time and the generation in evolution. This model allows us definite investigation on the interaction between learning and evolution. And the reinforcement of the robustness against the noise is also achieved in the evolutional scheme.     

基于Lukasiewicz t-模的模糊双向联想记忆网络的有效学习算法

利用t-模的伴随蕴涵算子,为基于Max和TL合成的模糊双向联想记忆网络Max-TLFBAM提供了一种新的学习算法,此处TL是Lukasiewicz t-模算子。从理论上严格证明了,只要存在有连接权矩阵对使得任意给定的模式对集成为Max-TLFBAM的平衡态集,则依该学习算法所确定的连接权矩阵对是所有这样的连接权矩阵对中的最大者。并用实验验证该学习算法的有效性。     

Extension from a linear associative memory to a linguistic linear associative memory

We present a linguistic extension from a crisp model by using a codification model that allows us to implement a fuzzy system on a discrete decision model. The paper begins with an introduction to the representation of fuzzy information, followed by a discussion of the codification method and the extension of a linear associative memory to a linguistic linear associative memory. Finally, we enumerate the advantages and disadvantages of the obtained linguistic linear associative memory. © 1998 John Wiley & Sons, Inc.13: 41–57, 1998     

Continuous classifying associative memory

In this article we present the so‐called continuous classifying associative memory, able to store continuous patterns avoiding the problems of spurious states and data dependency. This is a memory model based on our previously developed classifying associative memory, which enables continuous patterns to be stored and recovered. We will also show that the behavior of this continuous classifying associative memory may be adjusted to some predetermined goals by selecting some internal operating functions. © 2002 Wiley Periodicals, Inc.     

Navigation system including associative memory

A new adaptive linear robot control system for a robot work cell that can visually track and intercept stationary and moving objects undergoing arbitrary motion anywhere along its predicted trajectory within the robot's workspace is presented in this paper. The proposed system was designed by integrating a stationary monocular CCD camera with off-the-shelf frame grabber and an industrial robot operation into a single application on the MATLAB platform. A combination of the model based object recognition technique and a learning vector quantization network is used for classifying stationary objects without overlapping. The optical flow technique and the MADALINE network are used for determining the target trajectory and generating the predicted robot trajectory based on visual servoing, respectively. The necessity of determining a model of the robot, camera, all the stationary and moving objects, and environment is eliminated. The location and image features of these objects need not be preprogrammed, marked and known before, and any change in a task is possible without changing the robot program. After the learning process on the robot, it is shown that the KUKA robot is capable of tracking and intercepting both stationary and moving objects at an optimal rendezvous point on the conveyor accurately in real-time.     

An analog feedback associative memory

A method for the storage of analog vectors, i.e., vectors whose components are real-valued, is developed for the Hopfield continuous-time network. An important requirement is that each memory vector has to be an asymptotically stable (i.e. attractive) equilibrium of the network. Some of the limitations imposed by the continuous Hopfield model on the set of vectors that can be stored are pointed out. These limitations can be relieved by choosing a network containing visible as well as hidden units. An architecture consisting of several hidden layers and a visible layer, connected in a circular fashion, is considered. It is proved that the two-layer case is guaranteed to store any number of given analog vectors provided their number does not exceed 1 + the number of neurons in the hidden layer. A learning algorithm that correctly adjusts the locations of the equilibria and guarantees their asymptotic stability is developed. Simulation results confirm the effectiveness of the approach.     

A feedforward bidirectional associative memory

In contrast to conventional feedback bidirectional associative memory (BAM) network models, a feedforward BAM network is developed based on a one-shot design algorithm of O(p(2)(n+m)) computational complexity, where p is the number of prototype pairs and n, m are the dimensions of the input/output bipolar vectors. The feedforward BAM is an n-p-m three-layer network of McCulloch-Pitts neurons with storage capacity 2(min{m,n}) and guaranteed perfect bidirectional recall. The overall network design procedure is fully scalable in the sense that any number p=/<2(min{m,n}) of bidirectional associations can be implemented. The prototype patterns may be arbitrarily correlated. With respect to inference performance, it is shown that the Hamming attractive radius of each prototype reaches the maximum possible value. Simulation studies and comparisons illustrate and support these theoretical developments.     

Complex-valued multistate neural associative memory

A model of a multivalued associative memory is presented. This memory has the form of a fully connected attractor neural network composed of multistate complex-valued neurons. Such a network is able to perform the task of storing and recalling gray-scale images. It is also shown that the complex-valued fully connected neural network may be considered as a generalization of a Hopfield network containing real-valued neurons. A computational energy function is introduced and evaluated in order to prove network stability for asynchronous dynamics. Storage capacity as related to the number of accessible neuron states is also estimated.     

Operation of an associative memory

This paper describes the operation of an associative memory (LYAM) governed by only ordinary differential equations, useful for pattern clustering. Several computer simulations illustrate its operation as an unsupervised classifier, vector quantizer, and content-addressable memory.     

NDRAM: nonlinear dynamic recurrent associative memory for learning bipolar and nonbipolar correlated patterns

This paper presents a new unsupervised attractor neural network, which, contrary to optimal linear associative memory models, is able to develop nonbipolar attractors as well as bipolar attractors. Moreover, the model is able to develop less spurious attractors and has a better recall performance under random noise than any other Hopfield type neural network. Those performances are obtained by a simple Hebbian/anti-Hebbian online learning rule that directly incorporates feedback from a specific nonlinear transmission rule. Several computer simulations show the model's distinguishing properties.     

基于强化学习方法的访存调度算法

在现代处理器中,存储控制器是处理器芯片对片外存储器进行访问的管理者和执行者,其中对访存过程的调度算法会对实际访存性能产生十分重要的影响。针对已有调度算法在不同负载特征下自适应性不足的问题,提出了一种基于强化学习方法的ALHS算法,通过对访存调度中页命中优先时的连续页命中上限次数进行自适应调整,习得最优策略。多种不同典型访存模式的模拟结果显示,相比传统的FR-FCFS,ALHS算法运行速度平均提升了10.98%,并且可以获得近似于最优策略的性能提升,表明该算法能够自主探索环境并自我优化。     

Phase transitions in associative memory networks

Ideas from random graph theory are used to give an heuristic argument that associative memory structure depends discontinuously on pattern recognition ability. This argument suggests that there may be a certain minimal size for intelligent systems.     

A new neural associative memory model

We present a new associative memory model based on the Hamming memory, but where the winner-take-all network part is replaced by a layer of nodes with somewhat complex node functions. This new memory can produce output vectors with individual “don't know” bits. the simulations demonstrate that this memory model works appropriately. © 1992 John Wiley & Sons, Inc.     

Application of a bi-directional associative memory (BAM) network in computer assisted learning in chemistry

A computer assisted learning software based on a bi-directional associative memory (BAM) network was developed. The software was implemented to assist students in associating the names of the elements in the periodic table with their chemical symbols. The use of the BAM facilitates the analysis and interpretation of students' responses. The software package can be modified easily as an educational tool for other disciplines.     

参数化模糊联想记忆网络的学习算法

基于Dubois提出的带参数ξ的t-模T_ξ,提出了一种参数化的广义模糊联想记忆网络Max-T_ξ FAM。由于T_ξ中参数ξ的作用,在应用中Max-T_ξ FAM有更强的可调性和灵活性。接着利用T_ξ的伴随蕴涵算子,提出了Max-T_ξ FAM的一种有效学习算法。从理论上严格证明了,只要Max-T_ξ FAM能完整可靠地存储所给的多个模式对,则所提出的学习算法一定能找到使得网络能完整可靠存储这些模式对的所有连接权矩阵的最大者。最后,用实验说明了所提出的学习算法的有效性。     

Adaptive associative memories capable of pattern segmentation

This paper presents an adaptive type of associative memory (AAM) that can separate patterns from composite inputs which might be degraded by deficiency or noise and that can recover incomplete or noisy single patterns. The behavior of AAM is analyzed in terms of stability, giving the stable solutions (results of recall), and the recall of spurious memories (the undesired solutions) is shown to be greatly reduced compared with earlier types of associative memory that can perform pattern segmentation. Two conditions that guarantee the nonexistence of undesired solutions are also given. Results of computer experiments show that the performance of AAM is much better than that of the earlier types of associative memory in terms of pattern segmentation and pattern recovery.