Sensitivity analysis and optimization of vehicle–bridge systems based on combined PEM–PIM strategy

This paper presents a new optimization method for coupled vehicle–bridge systems subjected to uneven road surface excitation. The vehicle system is simplified as a multiple rigid-body model and the single-span bridge is modeled as a simply supported Bernoulli–Euler beam. The pseudo-excitation method transforms the random surface roughness into the superposition of a series of deterministic pseudo-harmonic excitations, which enables convenient and accurate computation of first and second order sensitivity information. The precise integration method is used to compute the vertical random vibrations for both the vehicle and the bridge. The sensitivities are used to find the optimal solution, with vehicle ride comfort taken as the objective function. Optimization efficiency and computational accuracy are demonstrated numerically.     

数字PID调节器应用中的几个技术问题

本文就数字PID调节器应用中的正、反作用、积分饱和、限位及手动/自动无扰动切换等几个技术问题进行了讨论,并提出了具体软件解决办法.     

我国GNP的单位根不确定性研究

对于一个实际的时间序列数据,我们并不知道其真正的数据生成过程,只能通过假设和基于假设的统计推断来确定。本文利用蒙特卡罗模拟进行有限样本的ADF检验。结果表明,当原假设是存在单位根,备择假设是趋势稳定时,ADF检验的势很低。这意味着,我国GNP存在单位根是不确定的。     

Virtual rights? Property in online game objects and characters

The new industry of Massively Multi-Player Online Role-Playing Games (MMORPGs) brings together two sets of fictions: the interactive stories of shared computer games and the legal devices of intellectual property. In these virtual worlds, scarcity need not exist, but players tend to prefer the competition it creates. This leads to the development of property rights within the game world and players trading real money for virtual objects, ‘land’ and characters. This new phenomenon brings with it familiar legal problems such as theft, fraud and ownership disputes. Game creators also challenge the right of the players to claim ownership outside the game world. The volume and value of the items traded make real money trading an important area of current interest for intellectual property lawyers. Something is being traded, but does it fit neatly into existing conceptions of property rights and who owns it? Analysing the novel problems that result from various theoretical perspectives (utilitarianism, labour-desert theory and personality theory) leads to the conclusion that with time, we will see the development of property rights for players in online games. This connects with a growing understanding that the traditional conception of copyright law dealing with creative work generated by the solitary author is becoming less appropriate in the new creative spaces that information and communications technology brings, where individuals are both consumer and producer. In virtual worlds, new forms of intellectual property, and perhaps even new rights, are taking shape.     

基于FPGA的VPN网关设计方案研究*

提出了一种基于FPGA的高速VPN网关的设计方案。它的特点是用FPGA方式完成VPN网关的实时处理,而将通用处理机置于数据通路之外,完成系统配置和管理功能。这种构架的VPN实时性好,可以线速处理IP包,而且易于管理。     

建设项目设计阶段投资控制系统的建立与分析

针对建设设计阶段独立使用价值工程、优化设计和限额设计等方法进行投资控制的局限性,借鉴系统论、控制论、信息论等思想和方法,建立了设计阶段投资控制系统。系统主要由探测元件、控制元件和执行元件组成,探测元件进行设计阶段的信息收集;控制元件通过审核将各项投资控制活动与投资控制目标进行对比,提出应对策略;执行元件完成应对策略。通过投资控制系统的执行,实现对设计阶段各项活动的全面系统控制,从管理层面上解决设计阶段投资控制活动割裂问题,进而改善设计阶段整体投资控制效果。     

砂砾层复合防渗体的研究与应用

哈达山水利枢纽工程防护区堤基的卵石有局部集中现象,见有超径卵石(大于110mm),地质条件复杂。施工中堤基防渗处理措施采用复合防渗体形式的截渗墙。文中针对施工中因地层受阻,造成相邻水泥土成墙单元间存在缺漏或水泥土截渗墙底呈现台阶状无法形成连续整齐的水泥土截渗墙,进行有效的处理。复合防渗体达到了哈达山水利枢纽防护区的防渗要求,为社会经济发展提供了保障。     

电熨斗在线温度检测系统的设计

针对电熨斗生产线上工人调温不准确且效率低下的问题,研发了一种电熨斗在线温度检测系统。介绍了该系统的硬件电路原理图和软件设计流程框图,并对其进行了误差修正,误差在1℃范围之内。利用该系统不仅能显示实时温度,还能显示周期性的最高、最低温度,利于生产线上进行多工位快速准确调温;实现与上位机的通信,方便厂家进行品质管理。     

Conceptualising improvisation in information systems security

Information Systems Security (ISS) has constantly been ranked as a key concern for Information Systems (IS) managers. Research in the field has largely assumed rational choice (functional) approaches to managing ISS. Such approaches do not give due recognition to the role of improvisation in ISS work. Empirical evidence in organisations suggests that in the context of dynamic, volatile and uncertain environments practitioners are both rational and adaptive (a manifestation of improvisation). In this paper, we conceptualise and demonstrate the manifestation of improvisation in ISS. In order to develop a better understanding of improvisation in ISS activities, hermeneutical and exegetical techniques were employed. Empirical data were collected through in-depth interviews in a single case study. The data obtained were analysed and interpreted hermeneutically. Generally it was found that improvisation is manifested in ISS activities. Implications of these and other findings for the scholarly community and for practical use are discussed.