烯烃催化裂解反应动力学的研究

根据脉冲微反条件下C5～C8烯烃裂解产物分布,建立烯烃裂解反应网络,通过参数估计方法确定反应网络动力学常数、反应活化能和指前因子.结果表明,随着碳数的增加,C5～C8烯烃单分子裂解反应速率加快.反应温度600℃时C5～C8正构烯烃裂解生成丙烯,其反应速率常数的比值为1:8.18:38.48:27.98,最快生成丙烯的是1-庚烯.反应温度相同,1-烯烃的主要裂解反应速率是碳数相同的2-甲基-2-烯烃的1.1～1.6倍.C5烯烃裂解为单、双分子裂化并存的反应体系,但双分子裂解反应速率远大于单分子裂解,双分子反应占优势.     

基于遗传算法求解两曲线间最短距离

针对传统算法求解平面两条曲线间最短距离较为困难的问题,提出一种基于遗传算法的求解方法.该方法通过交替求解一条曲线上样本点到另一条曲线上样本点之间最短距离的方式对问题的可行域进行优化搜索.并对传统遗传算法做了两方面的改进,一是根据曲线自身特征分区间选取初始种群,使其能够合理地分布在寻优空间;二是对交叉结果进行跟踪,确保交叉成功后的个体优于父代个体.最终实例验证结果表明,该算法能较好地收敛到此类问题的全局最优解.     

基于VB的软件授权

基于VB设计的注册方法,在无附加硬件的条件下,实现了善于硬件指纹技术的软件授权。     

复杂产品开发项目调度问题的模糊优化算法

对具有不确定时间参数的复杂产品开发项目调度问题,提出一种有效的模糊优化调度算法-基于预测的模糊BoP项目调度算法.首先,用模糊数表示不确定的时间参数,并构造相应的模糊数运算方法,对适合于确定性调度问题的BoP算法进行扩展,使其能处理模糊性时间参数.其次,修正了BoP算法中子项目调度方法,提高了算法的调度性能,降低了计算复杂度.大量的数值仿真实验表明,与基于启发式规则的调度算法相比,模糊BoP算法更适合于具有不确定时间参数的复杂产品开发项目调度问题.     

A multidimensional and hierarchical model of mobile service quality

Using mobile brokerage service as an example, we propose and test a multidimensional and hierarchical model of mobile service (m-service) quality using a sample of 338 respondents from the two largest m-service providers in China: China Mobile and China Unicom. Through three-stage validation, we are able to confirm all three levels of the proposed hierarchical structure where a customer’s perceived m-service quality includes primary dimensions of interaction, outcome, and environment qualities. Each primary dimension further has its sub-dimensions. Our empirical results also show that corporate image moderates the effects of environment and outcome qualities on the service quality. Our proposed model provides implications for future research on mobile commerce.     

Investigation of viscosity effect on droplet formation in T-shaped microchannels by numerical and analytical methods

Both numerical and analytical models have been developed to explore the viscosity effect of the continuous phase on drop formation at a T-shaped junction in immiscible liquids. The effects of the generalized power law coefficient, the power law exponent and the yield stress on the mechanism of drop breakup, final drop size and frequency of drop formation are studied by using the numerical three-dimensional volume of fluid model. Droplets coalescence in Bingham fluids is observed in the beginning transient period. The effect of yield stress on drop extension is also discussed. Predictions of drop size by using an analytical force balance show satisfactory agreement with simulation results for Newtonian and power law fluids with different viscosity ratios. The approximation error associated with the analytical model for Bingham fluids is also acceptable. This analytical model can greatly shorten the prediction time as compared with the numerical model, which is helpful for on-line control.     

Collective motion in non-reciprocal swarms

This paper studies a non-reciprocal swarm model that consists of a group of mobile autonomous agents with an attraction-repulsion function governing the interaction of the agents. The function is chosen to have infinitely large values of repulsion for vanishing distance between two agents so as to avoid occurrence of collision. It is shown analytically that under the detailed balance condition in coupling weights, all the agents will aggregate and eventually form a cohesive cluster of finite size around the weighted center of the swarm in a finite time. Moreover, the swarm system is completely stable, namely, the motion of all agents converge to the set of equilibrium points. For the general case of non-reciprocal swarms without the detailed balance condition, numerical simulations show that more complex self-organized oscillations can emerge in the swarms. The effect of noise on collective dynamics of the swarm is also examined with a white Gaussian noise model.     

方差优化问题的复杂性：从生产线到计算机网络

在许多工程系统中,方差优化对保持性能稳定、提高系统服务质量具有重要的意义.方差优化问题也是组合优化中较困难的二阶离散优化问题.通过引入完成时间方差和等候时间方差这2个重要的子类问题,具体论述了此领域的研究现状与最新理论进展,讨论了方差优化的2个重要特例问题的复杂性,指出了其中一个特例问题属于P类问题,其所有最优解均具有对称螺旋结构,且此螺旋型的结构还存在于一大类任意阶的偏差问题.基于方差问题的特性,总结并拓展了其在实际工程领域、特别是计算机网络系统领域的新应用.     

Consensus protocols for discrete-time multi-agent systems with time-varying delays

This paper addresses consensus problems for discrete-time multi-agent systems with time-varying delays and switching interaction topologies and provides a class of effective consensus protocols that are built on repeatedly using the same state information at two time-steps. We show that those protocols can solve consensus problems under milder conditions than the popular consensus algorithm proposed by Jadbabaie et al., specifically, the presented protocols allow for the case that agents can only use delayed information of themselves, whereas the popular one is invalid. It is proved that if the union of the interaction topologies across the time interval with some given length always has a spanning tree, then in the presence of bounded time-varying delays, those protocols solve consensus problems.     

基于嵌入式的悬架与转向集成控制器研究

为了改善车辆的操纵稳定性和行驶平顺性,提高汽车底盘控制的集成度,本文对底盘部分的半主动悬架SASS (Semi Active Suspension System)和电动动力转向EPS (Electric Power Steering)系统进行了集成控制研究.设计并试制出基于嵌入式系统ARM S3C44BOX的SASS和EPS集成控制器,并进行了台架试验,结果表明研制的集成控制器效果良好,可用于汽车底盘集成控制系统的开发研究.