基于小波神经网络的煤矿瓦斯涌出量预测

针对影响瓦斯涌出量的因素复杂多样化以及各因素之间的非线性问题,综合利用神经网络的自学习能力和小波变换的局部化性质,采用了一种基于黄金分割原理获得隐含层节点数的寻优算法,结合MATLAB强大的运算功能,建立了基于小波神经网络的煤矿瓦斯涌出量预测模型.仿真结果表明整个系统具有较强的逼近和容错能力,以及较快的收敛速度和良好的预报效果.     

A formal architectural model for logical agent mobility

The process of agent migration is the major difference between logical code mobility of software agents and physical mobility of mobile nodes in ad hoc networks. Without considering agent transfer, it would make little sense to mention the modeling of strong code mobility, which aims to make a migrated agent restarted exactly from the state when it was stopped before migration. From the perspective of system's architecture, this paper proposes a two-layer approach for the formal modeling of logical agent mobility (LAM) using predicate/transition (PrT) nets. We view a mobile agent system as a set of agent spaces and agents could migrate from one space to another. Each agent space is explicitly abstracted to be a component, consisting of an environmental part and an internal connector dynamically binding agents with their environment. We use a system net, agent nets, and a connector net to model the environment, agents, and the connector, respectively. In particular, agent nets are packed up as parts of tokens in system nets, so that agent transfer and location change are naturally captured by transition firing (token game) in Petri nets. Agent nets themselves are active only at specific places and disabled at all the other places in a system net. The semantics of such a two-layer LAM model is defined by transforming it into a PrT net. This facilitates the analysis of several properties about location, state, and connection. In addition, this paper also presents a case study of modeling and analyzing an information retrieval system with mobile agents.     

Injectable silk/hydroxyapatite nanocomposite hydrogels with vascularization capacity for bone regeneration

Localized and sustained osteogenic-angiogenic stimulation to bone defects is critical for effective bone repair.Here,desferrioxamine(DFO)was loaded on silk fibroin nanofibers and blended with hydroxyapatite nanorods(HA),forming injectable DFO-loaded silk fibroin-HA nanocomposite hydrogels.The composite hydrogels remained homogeneous distribution of HA with high ratio(60%)and also higher stiffness than that of pure silk fibroin nanofiber hydrogels,which provided stable osteogenic stimulation niches for tissue regeneration.Without the scarify of injectability,the hydrogels achieved slow delivery of DFO for above 60 days,resulting in suitable angiogenesis in vitro and in vivo and better osteogenesis than DFO-free systems.Compared to previous injectable silk fibroin-HA hydrogels,the introduction of vascularization capacity further stimulated the osteogenic differentiation of stem cells and accelerated new bone formation.Quicker and better bone healing were detected at defect sites after the injection of DFO-loaded nanocomposite hydrogels,indicating the effective synergistic effect of osteogenic and angiogenic cues.This work provides a simple and effective strategy of introducing angiogenic cues to bone matrices.We believe that the injectable nanocomposite hydrogels are suitable for the regeneration of bone tissues.     

The characteristics of waves around an entrance of a lagoon in South China Sea

The characteristics of the waves around a lagoon entrance in South China Sea were observed during the past one and half years based on the wave measurements.The...     

222Rn在大气输运研究中的示踪应用

本文简要回顾了222Rn及其子体示踪应用的主要方面,介绍了国内外对利用222Rn及其子体在预报地震和大气物质输运研究这两方面的工作.对这些示踪应用而言,要进行准确的定量分析和数值模拟,必须对222Rn及其子体在大气中的输运规律有细致的了解,这一点可以通过研究其动力学特征,建立输运模型来实现.本文中列举了部分对222Rn及其子体输运模式的研究,对比上层大气中的简单输运模型,一个比较全面的222Rn输运模型还需要考虑地表层结大气中的复杂的动力学因素,并将其作为222Rn在上层大气输运模型中的下垫面边界条件.     

基于两级算法的对偶控制

考虑具有未知参数的随机系统的最优控制问题.采用包含新息方差指数项的损失函数优化系统的性能.新的损失函数由两部分组成:第一部分反映了对输出的调节作用;第二部分反映了辩识系统中未知参数应尽可能多地收集系统信息的需求.提出了一种两级优化算法.该算法首先把不可分问题转化为可分的两目标优化问题,再从两目标优化的非劣解集中挑出原问题的最优解.该控制律易于实施且具有对偶特点.仿真结果表明本文所得的控制律的有效性.     

捷联式惯导系统在车辆监控中的实现与应用

在道路交通飞速发展的今天,道路安全问题日益成为社会关注的焦点。特别是危化品货物的道路运输安全问题,已成为交通运输管理部门面临的重大难题。依据捷联式惯导系统和四元数法,提出车辆实时监控模型,并应用在危化品运输智能监控平台中。实验结果表明该模型是有效可行的。     

The globally asymptotic stability analysis for a class of recurrent neural networks with delays

This paper considers the problem of global stability of neural networks with delays. By combining Lie algebra and the Lyapunov function with the integral inequality technique, we analyze the globally asymptotic stability of a class of recurrent neural networks with delays and give an estimate of the exponential stability. A few new sufficient conditions and criteria are proposed to ensure globally asymptotic stability of the equilibrium point of the neural networks. A few simulation examples are presented to demonstrate the effectiveness of the results and to improve feasibility.     

掺杂荧光染料的高亮度有机蓝光电致发光器件

利用蓝色发光材料DPVBi掺杂高荧光染料rubrene做发光层制备了蓝色发光器件.在掺杂浓度为1.5%(wt)左右的情况下,当改变掺杂层的总的厚度时,器件的亮度、效率和色坐标都有明显的改变.当掺杂层DPVBi和rubrene的厚度为40nm,电子传输层Alq3的厚度为20nm,器件所加的电压是13v时,其最大亮度为14000cd/m2,此时的色坐标为(0.24,0.24),为蓝光发射.这种掺杂明显的提高了蓝光器件的发光效率.使最大效率达到2.5cd/A.     

基于离散LOD-Imposter技术的森林实时渲染算法研究及实现

森林植被的实时可视化技术是复杂虚拟环境渲染的重要组成部分,也是影响虚拟环境逼真度的重要因素。提出了一种基于离散LOD和Imposter相结合技术的森林实时渲染算法,该算法利用像素作为LOD选择参数,通过像素阈值判定对不同面数的模型进行选择渲染,使用二叉树遍历算法对场景中树的节点进行遍历,利用Imposter技术对距离较远的模型用一张texture代替。通过使用关键帧增加树的动画效果,利用动态的光影效果提高树的真实性。该算法能够很好地模拟大规模森林的效果,满足了对大规模森林进行漫游的实时性的要求。