基于智能体技术的人员群集流动动力学模型

目的运用计算机技术研究复杂的群集流动现象，设计和优化人员疏散系统．解决群集人员流动安全管理问题．方法吸取社会力模型中行人运动受到社会力支配的思想，综合考虑行人之间的相互影响，利用智能体技术，在人员流动行为规则的指导下，建立群集流动的微观动力学模型，借助自适应网格生成技术实现了人员群集流动的计算机模拟．结果对仅有一个出口的大房间和设有障碍的通道的人员疏散过程进行了模拟，模拟动画图像显示了人员流动过程中在流动通道瓶颈处的成拱现象及行人流避让和绕过障碍的现象．结论通过群集流动微观动力学模型并借助自适应网格生成技术，实现了对于人员群集流动状态及其演化过程的计算机模拟．提高了运算速度．表明本模型具有一定的适用性．     

密集波分复用技术及其应用

随着网络带宽的剧烈增长和对服务质量的要求不断提高，密集波分复用技术（DWDM）和全光网络正成为研究的热点。通过在一条光纤上传输多个波长的光信号，DWDM能够极大提高光网络的传输能力。在全光网络中，信息的传输和处理都是在光域中进行的。本文对近期的DWDM和全光网络的研究进行了回顾，特别关注了以IP over DWDM为基础的光因特网的进展。     

场景监控中的人群密度估计

人群密度估计是智能化人群监控中十分重要的内容，它对于人民群众的生命安全有着重要的作用和意义。本文提出了一种基于小波变换与灰度共生矩阵的人群密度特征提取方法，进而利用支撑向量机实现人群密度级别的估计。实验结果表明本文提出的方法是可行的。     

Hydrogen production by partial oxidation of methane: Modeling and simulation

A one-dimensional non-isothermal model for oxygen permeable membrane reactor has been developed to simulate the partial oxidation of methane to produce hydrogen. The performance of two fixed bed reactors (FBRs) viz. one with pure O₂ in feed (FBR1), other with air in feed (FBR2), and a membrane reactor (MR) having air in non-reaction side have been studied at various feed conditions and inlet temperatures in order to investigate the effect of these parameters on conversion of methane and yield of hydrogen. The fixed bed reactor with pure O₂ in feed has been found to provide better performance as compared to fixed bed reactor with air and membrane reactor.     

Polynomial Time Approximation Schemes for Some Dense Instances of NP-Hard Optimization Problems

We survey recent results on the existence of polynomial time approximation schemes for some dense instances of NP-hard combinatorial optimization problems. We indicate some inherent limits for the existence of such schemes for some other dense instances of optimization problems. We also go beyond the dense optimization problems and show how other approximation problems can be solved by using dense techniques. Received October 30, 1997; revised June 25, 1999, and April 17, 2000.     

基于密实核理论的单滚刀多阶段受力预测模型

基于密实核理论,针对特定岩石条件,考虑滚刀在破岩过程中复杂的受力情况,将滚刀楔形刃破岩过程分为四个阶段:弹性变形阶段、挤压破碎阶段、密实核破碎阶段与卸载阶段,且认为在密实核破碎阶段,密实核处于静水压状态,静水压力增大,会使受力物体的体积缩小,但不会改变其形状。并提出了单滚刀多阶段受力预测模型。进而开展了单滚刀线性切割岩石试验研究,并与理论模型进行了对比。结果表明:预测模型与实验数据垂直力、侧向力和滚动力的误差分别在(8~18)k N,(2~5)k N和(0~3)k N;在此基础上对预测模型进行了系数修正,使其能够更加真实地模拟滚刀破岩的受力情况,为滚刀以及刀盘的设计提供技术支撑。     

大型液压挖掘机斗杆挖掘阻力的离散元素法研究

针对由于缺乏铲斗挖掘阻力等关键数据而导致在大型正铲液压挖掘机工作装置、液压系统设计时只能采用类比法而造成整机性能差的问题,对挖掘机斗杆挖掘阻力进行了离散元研究,提出了一套仿真评估方法:运用离散元素法,在EDEM中建立了矿堆模型,通过选择Hertz-Mindlin无滑动接触模型计算了元素间接触力,模拟了大型正铲液压挖掘机斗杆挖掘工况,分析研究了挖掘过程中铲斗所受挖掘阻力。将EDEM中所得挖掘阻力加载到ADAMS挖掘机动力学模型,进行工作装置和液压回路参数校核以及挖掘阻力实验验证。研究结果表明,挖掘阻力的仿真与计算为大型液压挖掘机工作装置和液压系统设计提供了可靠依据。     

Social context cognition crowd‐sourcing and semi‐automatic parametrization

This paper presents a semi‐automatic method of parameterizing an existing social context cognition model. It discusses benefits of the social context cognition models for example in personality modeling and their key issue that is parametrization. It briefly introduces social context cognition model and describes a new method of its crowd‐sourcing‐based parametrization. Later, validation is provided, and ability to recreate social context cognition in the provided samples is presented with good generalization for the unknown cases. Finally, model's stability for the continuous stream of dynamic social context input data is shown. Presented system contributes to the believable agent modeling and social simulations by making much needed applications of social context cognition models easier by addressing the so far unsolved troublesome parametrization issues. Copyright © 2016 John Wiley & Sons, Ltd.     

认知无线电系统中基于量子粒子群算法的PHY层及MAC层决策优化

认知无线电技术是下一代通信发展的方向和趋势,同时也是目前通信研究中的热点问题。针对认知无线电系统中,在某一信道条件下其通信系统的物理层（PHY）和媒体链路层（MAC）的基于多个目标来实现优化的问题,基于量子粒子群算法的基本思想,把量子粒子群算法引入认知无线电系统中,并对该算法进行适当的改进,最后基于WSGA控制对电台优化问题进行了仿真,通过仿真证明了其有效性。     

Concentration and pressure measurements of dense sand and gravel multiphase flows under transient flow conditions in a vertically oriented closed conduit — Assessment of system and sensor performance

The hydraulic transport of sediments in sediment–water multiphase mixtures is an important process in nature and many industrial applications. The flows are characterized by complex transient phenomena, in which the overall system scale and the particle scale are equally important. Experimental research into dense mixture flows is focused on measurement of flowrates, differential pressures and concentrations of the suspended sediments.Concentration measurements are especially challenging in the case of coarse particles (beyond millimeter size scale) flowing in dense mixtures, limiting the range of available sensors for accurately measuring the in-situ solids concentrations. For the investigation of transient processes, a quick sensor response is required, which makes concentration measurement based on mixture conductivity an interesting option.This study is focused on combined concentration and pressure measurements in dense sediment–water mixtures with coarse particles in a vertically oriented closed conduit, using differential pressure sensors over the vertical segments and conductivity probes for measuring the mixture concentration. We experimentally investigated the dispersion process of an initially densely packed batch of sand and gravel by measuring the concentration on different segments of the conduit, resulting in data on mixture wall shear stresses for different sand and gravel mixtures and data of attenuation of concentration gradients in vertical upward and downward flow, in the conduit horizontal top section and in the centrifugal pump.We describe in the detail the sensor calibration and data processing method, giving a best practice for the use of conductivity concentration sensors in dense coarse particle mixtures, and we suggest a novel method for analysis of density wave amplification and attenuation based on concentration measurements in general, which allows for the detailed analysis of transient multiphase flow phenomena at pipe system component level.