Web环境下公路工程造价审查系统研究

针对目前公路工程造价审查体系存在的问题，在分析群体决策支持系统、多Agent和数据库技术发展趋势的基础上，对Web环境下的公路工程造价审查系统的体系框架进行了优化设计。并提出了造价资料的分步综合审查法。     

Experimental modeling of controlled suspension vehicles from onboard sensors

In this article, identification of vertical dynamics of vehicles with controlled suspensions is considered. Identification is performed from experimental data measured on a four-poster bench test of a segment C car, equipped with a CDC-Skyhook dampers control system. The measurements are obtained from the onboard accelerometers needed by the control system. A nonlinear model in regression form is identified, having the road profile and damper control currents as inputs and chassis accelerations as outputs. The model is identified by means of a set membership structured identification method, which takes advantage of physical information on the structure of the system, decomposing the system into three subsystems: one represents the chassis and engine and the other two represent the overall behavior of front and rear suspensions, wheels and tires. This decomposition allows us to avoid the complexity accuracy problems derived from the high dimension of required regression space. Indeed, the overall high-dimensional identification problem is reduced to the identification of lower dimensional subsystems and to the estimation of their interactions. An iterative scheme is used for solving the decomposed identification problem. As the chassis pitch is small for the usual road profiles, the chassis-engine block is considered linear and standard linear methods are used for its identification. The other two subsystems are the main sources of nonlinearities in the system, mainly due to the significant nonlinearities of controlled dampers and of tires. Owing to the complexity/accuracy problems of a physical modeling of these subsystems, an input-output approach is taken. In particular, a nonlinear set membership method that does not require the search of the functional form of involved nonlinearities is used for the identification of these subsystems. The iterative algorithm converged in two iterations to a model providing a quite satisfactory simulation accuracy for all the considered road profiles and CDC-Skyhook settings.     

液压系统防止振动的解析方法

在实际工程中,为防止液压冲击及振动,常采用控制流量、阀门关闭时间的经验方法,但用此法至今尚无解析计算的精确公式.本文运用联锁理论,突破了目前机械工程中使用的经验公式的局限,得到了精确的分析结果,并充分表明了不同初始条件对瞬态过程的影响,对防止液压系统冲击、振动具有一定的实际工程意义.     

Finite-Time Stability of Nonautonomous Delayed Systems

The finite-time stability to linear discontinuous time-varying delayed system was investigated. By applying the method of upper and lower solutions, some sufficient conditions of this kind of stability were obtained. Furthermore, it also developed a monotone iterative technique for obtaining solutions which are obtained as limits of monotone sequences     

蕴涵算子

文中给出了蕴涵算子的定义，讨论了蕴涵算子的一些基本性质及生成方法，建立了蕴涵算子之间的运算，并构造了一个蕴涵算子范畴。     

基于模糊聚类方法的ITS需求分析

ITS需求分析是ITS规划的基本步骤之一．文中将模糊聚类方法应用于ITS需求分析，并且利用VBA语言编制了相应的计算程序．根据北京奥运交通规划课题组的专家调查数据，对奥运ITS的部分需求进行了分析，采用三种方式得到的初步分析结果具有较高一致性，最终分析结果有效地反映了研究对象的特征及其相互关系，验证了模糊聚类方法在ITS需求分析方面的实用价值．     

Multimodal Evolution Approach to Multidimensional Intrusion Detection

An artificial immunity based multimodal evolution algorithm is developed to generate detectors with variable coverage for multidimensional intrusion detection. In this algorithm, a proper fitness function is used to drive the detectors to fill in those detection holes close to self set or among self spheres, and genetic algorithm is adopted to reduce the negative effects that different distribution of self imposes on the detector generating process. The validity of the algorithm is tested with spherical and rectangular detectors, respectively, and experiments performed on two real data sets （machine learning database and DAPRA99） indicate that the proposed algorithm can obtain good results on spherical detectors, and that its performances in detection rate, false alarm rate, stabih＇ty, time cost, and adaptability to incomplete training set on spherical detectors are all better than on rectangular ones.     

经济增长要素中的高等教育投资

高等教育投资作为生产性投资的观点已经被社会承认．通过对1990—2000年我国对教育及高等教育的投资，利用生产函数表示的教育与经济增长的关系模型，进行回归分析．通过分析，得出影响我国经济增长的各因素中，资本仍然起着主要作用，高等教育对经济增长的贡献很小，这与我国在2000年以前对高等教育的投资过少密切相关，说明我国增加对高等教育的投资与高等教育大扩招的必然性．     

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针对城市现代物流系统规划问题的特点，以及规划缺乏完整理论和方法指导的现实，结合深圳等市现代物流系统规划的实践，采用软系统方法论构建了城市现代物流系统规划的方法，该方法可以成为指导实际规划工作的指南.     

结构振动分析中的键图法

本文应用键因法对铁道车辆结构的集总-分布混合系统进行振动分析。车辆的转向架构架简化为H型,视为由三根伯努利—欧拉梁组成。将各梁的四个低阶模态取为集总质量,与车体悬挂,轮轨相互作用等构成多体系统,用键图法模拟,通过数值计算,求解系统的频率响应。结果表明:用键因法对混合系统进行振动分析,与有限元法相比。比较直观,且有明显的物理意义,便于修改模型,计算工作量小,故作者最后建议,进一步推广和研究键图法在结构振动分析中的应用。