Analysis of global exponential stability for a class of bi—directional associative memory networks

In real-time applications of bi-directional associative memory (BAM) networks.a global exponentially stable equilibrium is highly desired.The existence,uniqueness and global exponential stability for a class of BAM networks are studied in this paper,the signal function of neurons is assumed to be piece-wise linear from the engineering point of view.A very concise condition for the equilbrium of such a network being globally exponentially stable is derived.which makes the pactical design of this kind of networks an easy job.     

多时滞神经网络关于滞量上界的一个估计

通过构造适当的Lyapunov函数和一些分析技巧,研究了一类多时滞的双层联想记忆神经网络模型,提供了该网络的平衡点的全局渐近稳定性关于滞量的一个上界,这样的一个上界关于全局稳定网络的设计在理论与应用上都有极其重要的意义,所获结果推广了已有文献中的相关结论.     

具有时滞的双向联想记忆(BAM)的神经网络的全局动力学行为

在没有假定关联函数的光滑性,单调性和有界性的条件下,应用Liapunov泛函方法和矩阵代数技术,得到具有常数传输时滞的双向联想记忆(BAM)的神经网络模型平衡点存在性和全局指数稳定性的一些新的充分条件,这些条件可以由网络参数,连接矩阵和关联函数的Lipschitz常数所表示的M矩阵来刻化．这些结果不仅是简单和实用的,而且相对于已有文献的结果具有较少的限制和更易于验证．     

STABILITY OF DISCRETE-TIME COHEN-GROSSBERG BAM NEURAL NETWORKS WITH DELAYS

In this paper, we study the existence and stability of an equilibrium of discrete-time Cohen-Grossberg BAM Neural Networks with delays. We obtain several sufficient conditions ensuring the existence and stability of an equilibrium of such systems, using discrete Halanay-type inequality and vector Lyapunov methods. In addition, we show that the proposed sufficient condition is independent of the delay parameter. An example is given to demonstrate the effectiveness of the results obtained.     

Langmur monolayers of cerebroside with different head groups originated from sea cucumber: Binary systems with dipalmitoylphosphatidylcholine (DPPC)

Surface properties (Langmuir monolayer) of two different cerebrosides which are extracted from the sea cucumber (Bohadschia argus) were investigated. A main difference in chemical structure of cerebroside between BAC-2a and BAC-4 is their head groups (glucose and galactose, respectively). Furthermore, miscibility and interaction between dipalmitoylphosphatidylcholine (DPPC) and cerebrosides (BAC-2a and BAC-4) in the monolayer have been systematically examined. The surface pressure (π)−area (A), the surface potential (ΔV)−A, and the dipole moment (μ)−A isotherms for monolayers of DPPC, cerebrosides, and their binary combinations have been measured using the Wilhelmy method and the ionizing electrode method. BAC-4 forms a stable liquid-expanded (LE) monolayer, whereas BAC-2a has a first-order phase transition from the LE phase to the liquid-condensed (LC) state on 0.15 M NaCl at 298.2 K. The fundamental properties for each cerebroside monolayer were elucidated in terms of the surface dipole moment based on the three-layer model [R.J. Demchak, T. Fort Jr., J. Colloid Interface Sci. 46 (1974) 191–202] for both cerebrosides and the apparent molar quantity change (Δs^γ, Δh^γ, and Δu^γ) for BAC-2a. In addition, their miscibility with DPPC was examined by the variation of the molecular areas and the surface potentials as a function of cerebroside mole fractions, the additivity rule. The miscibility was also confirmed by constructing the two-dimensional phase diagrams. The phase diagrams for the both binary systems were of negative azeotropic type. That is, the two-component DPPC/BAC-2a and DPPC/BAC-4 monolayers are miscible. Furthermore, the Joos equation for the analysis of the collapse pressure of binary monolayers allowed calculation of the interaction parameter and the interaction energy between the DPPC and cerebroside monolayers. The miscibility in the monolayer state was also confirmed by the morphological observation with Brewster angle microscopy (BAM), fluorescence microscopy (FM), and atomic force microscopy (AFM).     

多比例时滞杂交双向联想记忆神经网络的全局指数稳定性

考虑多比例时滞杂交双向联想记忆神经网络的全局指数稳定性．应用Brouwer不动点定理证明了多比例时滞杂交双向联想记忆神经网络平衡点的存在性,再通过构造合适的Lyapunov泛函,获得了该系统平衡点全局指数稳定的时滞依赖的充分条件,该条件蕴含系统平衡点的唯一性,并给出了一个例子说明结论的有效性．     

High-Order BAM, Its Modifications and Performance Analyses

Based on Tai' s high - order bidirectional associative memory ( HOBAM) and Stmposon' s intraconnected BAM (IBAM) , two Improved models are first presented and discussed in this paper. The improved models not only retain the advantages of both HOBAM and ISAM but overcome the shortcomings of Kosko' s BAM also. Secondly their recall stabilities in synchronous and asyn-chronous update modes have been proven by defining corresponding energy functions which decrease as the re-call process proceeds such that the systems can ensure all the training pattern pairs to become local minima of the energy surfaces. Finally with signal - to - noise ratio (SNR) approach, we show that their storage capacities and error correction capabilities are better than that of the HOBAM.     

故障模式的联想记忆和识别分析

分析了故障模式的矩阵存储的机理，采用神经网络的联想存储方式来存储邦联模式，完成故障诊断，针对ＢＡＭ容量限制问题，用了一种多重矩阵存储法有效地解决了这一问题，并用一锅炉给水控制系统的故障诊断作为示例。     

EXISTENCE AND STABILITY OF PERIODIC SOLUTIONS OF DELAYED BAM NEURAL NETWORKS WITH PERIODIC COEFFICIENTS

In this paper, we study the BAM neural networks with variable coefficients and delays. By using the Banach fixed point theorem and constructing suitable Lyapunov function, we obtain some sufficient conditions ensuring the existence, uniqueness and global stability of periodic solution. These results are helpful to design global exponential stable BAM networks and periodic oscillatory BAM networks.     

Adsorption of DNA onto anionic lipid surfaces

Currently self-assembled DNA delivery systems composed of DNA multivalent cations and anionic lipids are considered to be promising tools for gene therapy. These systems become an alternative to traditional cationic lipid–DNA complexes because of their low cytotoxicity lipids. However, currently these nonviral gene delivery methods exhibit low transfection efficiencies. This feature is in large part due to the poorly understood DNA complexation mechanisms at the molecular level. It is well-known that the adsorption of DNA onto like charged lipid surfaces requires the presence of multivalent cations that act as bridges between DNA and anionic lipids. Unfortunately, the molecular mechanisms behind such adsorption phenomenon still remain unclear. Accordingly a historical background of experimental evidence related to adsorption and complexation of DNA onto anionic lipid surfaces mediated by different multivalent cations is firstly reviewed. Next, recent experiments aimed to characterise the interfacial adsorption of DNA onto a model anionic phospholipid monolayer mediated by Ca^2 + (including AFM images) are discussed. Afterwards, modelling studies of DNA adsorption onto charged surfaces are summarised before presenting preliminary results obtained from both CG and all-atomic MD computer simulations. Our results allow us to establish the optimal conditions for cation-mediated adsorption of DNA onto negatively charged surfaces. Moreover, atomistic simulations provide an excellent framework to understand the interaction between DNA and anionic lipids in the presence of divalent cations. Accordingly,our simulation results in conjunction go beyond the macroscopic picture in which DNA is stuck to anionic membranes by using multivalent cations that form glue layers between them. Structural aspects of the DNA adsorption and molecular binding between the different charged groups from DNA and lipids in the presenceof divalent cations are reported in the last part of the study. Although this research work is far from biomedical applications, we truly believe that scientific advances in this line will assist, at least in part, in the rationaldesign and development of optimal carrier systems for genes and applicable to other drugs.