船舶电力系统的动态过程仿真研究

提出了一种面向船舶电力系统动态过程的仿真计算方法.以连网柴油发电机组旋转坐标系为参考,建立了一种船舶电力系统教学模型,微分代数方程组求解采用牛顿法与隐式梯形积分法相结合.柴油机调速器依据速度下倾特性控制电网频率和有功功率分配,自动电压调节器引入均压线概念.选用中铁渤海一号船舶电力系统为仿真对象,实现柴油发电机组并联运行的动态过程仿真,仿真结果验证了数学模型和仿真计算方法的有效性.     

Secure and efficient elliptic curve cryptography resists side-channel attacks

An embedded cryptosystem needs higher reconfiguration capability and security. After analyzing the newly emerging side-channel attacks on elliptic curve cryptosystem (ECC), an efficient fractional width-w NAF (FWNAF) algorithm is proposed to secure ECC scalar multiplication from these attacks. This algorithm adopts the fractional window method and probabilistic SPA scheme to recondigure the pre-computed table, and it allows designers to make a dynamic configuration on pre-computed table. And then, it is enhanced to resist SPA, DPA, RPA and ZPA attacks by using the random masking method. Compared with the WBRIP and EBRIP methods, our proposals has the lowest total computation cost and reduce the shake phenomenon due to sharp fluctuation on computation performance.     

A differential game model for a developing and a developed country

A differential game (DG) model for a developing and a developed country is considered. Each player makes decisions about how much resource to be used to restrict the opponent's development so as to maximize his weighted sum of current consumption and final output. Current consumption is assumed to be preferred to final output for both players. The developing country is assumed to have a higher economic growth rate and a higher preference to final output, whereas the developed country is assumed to have a higher initial income and a higher efficiency in restricting his opponent. This problem is investigated under three kinds of information structures, i.e., a zerosum, a nonzero-sum, and a Stackelberg game. Open-loop equilibrium solutions are obtained for all the three cases. Economic implications of the result are provided. The research is supported by the National Natural Science Foundation of China under Grant Nos. 70771118 and 70371030 and the Scientific Research Foundation for the Returned Overseas Chinese Scholars, State Education Ministry under Grant No. 2006.331.     

Testing serial correlation in semiparametric varying coefficient partially linear errors-in-variables model

The authors propose a V _{N, p} test statistic for testing finite-order serial correlation in a semiparametric varying coefficient partially linear errors-in-variables model. The test statistic is shown to have asymptotic normal distribution under the null hypothesis of no serial correlation. Some Monte Carlo experiments are conducted to examine the finite sample performance of the proposed V _{N, p} test statistic. Simulation results confirm that the proposed test performs satisfactorily in estimated size and power. This research is supported by the National Natural Science Foundation of China under Grant Nos. 10871217 and 40574003; the Science and Technology Project of Chongqing Education Committee under Grant No. KJ080609; the Doctor's Start-up Research Fund under Grant No. 08-52204; and the Youth Science Research Fund of Chongqing Technology and Business University under Grant No. 0852008.     

一种求解函数优化的混合差分演化算法

为了解决传统遗传算法易陷入局部最优解的问题,在多父体杂交算法和差分进化算法的基础上,提出了混合差分演化算法.该算法的核心在于,采用多父体杂交算子保证算法的遍历性,通过淘汰相同个体来保持群体的多样性,并以较小概率随机选取部分个体进行差分进化操作,从而充分利用最优个体的信息达到了加快收敛速度的目的.对复杂函数的寻优实验验证了混合差分演化算法的有效性.     

一种结合形状上下文分析的Laplace谱匹配算法

提出了一种结合形状上下文分析的Laplace谱匹配算法.工作主要侧重于如何提高Laplace谱匹配算法对点的位置随机抖动的鲁棒性.首先,使用Laplace矩阵的特征向量和特征值以及双随机矩阵的方法计算初始匹配概率.然后,借助于概率松弛算法,将用形状上下文表示的局部相似性融入Laplace谱匹配算法以优化谱匹配的结果.对真实和合成数据的实验表明该方法具有比较高的精度.     

一种多目标优化问题的混合优化算法

利用分布估计算法(EDA)的全局搜索性能及差分进化(DE)算法的局部优化能力,提出了一种多目标优化问题的混合智能求解方法DE-EDA.DE-EDA的子代个体由两部分构成,一部分按差分进化算法生成,另一部分则是通过对分布估计算法的概率模型进行随机采样生成.利用模拟退火技术在线调整尺度因子Pr,即在进化的初期选择较大的Pr,以保证EDA起主导作用,由EDA引导DE搜索向Pareto前端,增加全局搜索能力,然后在进化的过程中逐渐降低Pr,使得DE逐渐占据主导作用,确保解精确收敛到Pareto前端.通过4组基准函数来测试算法性能,并与NSGA-Ⅱ和DE算法进行实验比较,结果表明该方法不仅解的多样性和分布性好,而且能够有效提高种群进化的收敛速度,是一种求解多目标优化问题的有效方法.     

混沌差分文化算法及其仿真应用研究

针时差分进化算法(DE)全局寻优能力差,无法有效的求解工程中复杂的高维非线性优化问题等缺点,提出一种混沌差分文化算法(CDECA).该算法模型将DE嵌入文化算法的框架作为主群体空间的进化过程,同时,引入具有较强局部搜索性能的混沌搜索来进行信念空间的进化,并通过设计一组联系操作实现文化算法模型中两个空间的互相影响互相促进,提高算法的寻优效率.几个典型测试函数的测试结果表明CDECA的搜索能力优于DE,将其应用于某大型水库的优化调度,也取得满意的效果.     

可跨工位操作的随机混流装配线平衡问题研究

装配线平衡问题是在满足一定约束的条件下,将一系列任务单元分配到各个工位上,使其工作强度与利用率相适应.研究了带有跨工位操作,且任务单元完成时间为随机量的一类特殊装配线平衡问题,目标是缩短整个生产过程中的总任务超载时间;参考机会约束规划的思想,建立了α任务超载时间最小化模型;结合随机模拟和遗传算法设计了混合遗传算法以求解,并通过实例仿真验证了算法的有效性.     

分段连续型延迟Logistic方程Runge-Kutta方法的稳定性

讨论了用Runge-Kutta方法求解分段连续型延迟Logistic方程的稳定性,分析了直接运用Runge-Kutta方法会产生伪解,从而建立了不产生伪解的Runge-Kutta方法,讨论了该方法的收敛阶,证明了该方法是局部和全局渐近稳定的.数值实验进一步验证了算法理论分析的正确性.