Mean first passage time of active Brownian particle in one dimension

We investigate the mean first passage time of an active Brownian particle in one dimension using numerical simulations. The activity in one dimension is modelled as a two state model; the particle moves with a constant propulsion strength but its orientation switches from one state to other as in a random telegraphic process. We study the influence of a finite resetting rate r on the mean first passage time to a fixed target of a single free active Brownian particle and map this result using an effective diffusion process. As in the case of a passive Brownian particle, we can find an optimal resetting rate r* for an active Brownian particle for which the target is found with the minimum average time. In the case of the presence of an external potential, we find good agreement between the theory and numerical simulations using an effective potential approach.     

基于QUALIFLEX和LINMAP的简化中性犹豫模糊多属性决策方法

在处理多属性决策问题中,QUALIFLEX是一种非常有用的排序算法。针对属性取值为简化中性犹豫模糊集的多属性决策问题,提出了SNHFS-QUALIFLEX算法。另外考虑到属性权重不确定的情况,将LINMAP扩展到简化中性犹豫模糊集中,定义了符号距离,建立了最优数学规划模型来确定属性权重。最后将SNHFS-QUALIFLEX方法应用到多属性决策实例中,并验证了其可行性和有效性。     

基于实时公交信息的乘客乘车决策研究

实时交通信息的发布使乘客出行更具灵活性.调查乘客对实时公交系统的应用情况及功能需求,并提取乘客乘车决策规则.考虑乘客决策的"有限理性"特征构建决策模型:将乘车舒适性因素转换为时间成本,运用云模型建立定量时间到定性概念的映射;依据出行参考点确,定出行方案的因素权重,建立期望效用函数;构建不同的出行场景,运用决策模型进行出...     

电商平台主导的E-闭环供应链定价、服务决策与回收模式

E-闭环供应链(E-CLSC)管理须有科学的定价与服务决策支撑。针对集中和分散回收模式,构建电商平台主导的Stackelberg博弈模型,研究E-CLSC定价与平台服务决策。通过对产品销售价格、平台服务水平等均衡策略分析,揭示回收主体投资有效性、回收转移价格等对E-CLSC均衡策略影响。研究表明:集中回收模式优于分散回收模式;在分散回收模式下,若回收主体投资有效性相同,制造商、平台均偏好制造商回收模式;平台回收与第三方回收模式相比,产品销售价格、平台服务水平相同,前者回收渠道效率较高;平台回收模式下,单位佣金与回收转移价格负相关,产品销售价格、平台服务水平、废旧产品回收率均与回收转移价格无关;若回收主体投资有效性差异程度较大,制造商回收模式并非总是最优的,回收主体投资有效性差异显著影响产品销售价格、回收渠道效率、平台服务水平和E-CLSC各成员利润。上述结论通过数值仿真进行了验证。     

条件非线性最优扰动方法在陆面过程模式参数优化中的扩展应用初探

本文旨在探讨条件非线性最优扰动(CNOP)方法在陆面过程模式的参数优化工作方面的扩展应用.使用通用陆面模式(CoLM)和CEOP地面基准站——吉林通榆站退化草地2006年生长季的资料,针对土壤颜色、砂土比例和叶面积指数等关键模式参数,使用感热通量、潜热通量和浅层土壤温湿度作为检测变量,设计了单参数和多参数优化试验.结果表明,CONP扩展方法得到的优化参数提高了CoLM对检测变量的模拟能力,并且多参数的优化结果明显优于单参数的优化结果,在模式模拟偏差较大的土壤湿度方面改进尤为显著,此外,使用了差异进化算法( 关键词： 条件非线性最优扰动(CNOP) 陆面过程模式 参数优化     

基于相似度和改进雷达图的概率犹豫模糊多属性决策方法

为了解决属性权重未知的概率犹豫模糊多属性决策问题,构建基于相似度和改进雷达图的多属性决策方法。首先基于概率犹豫模糊元的信息完全度构建概率犹豫模糊集的距离测度和灰色关联系数,然后基于灰色关联理想解法定义了概率犹豫模糊集的相似度,最后根据概率犹豫模糊集的相似度和改进雷达图构建多属性决策模型,并通过案例进行了验证分析。     

估计感度分布中位数的两阶段优化序贯试验设计方法研究

感度试验在爆炸科学领域有非常广泛的应用,其中位数是含能材料的一个关键性能指标.高效估计感度分布中位数是实际工程应用中的重要问题.文章提出一种两阶段的优化序贯试验设计方法来估计感度分布的中位数,并将正交设计与两阶段优化序贯试验设计方法相结合给出了筛选影响含能材料安定性重要因子的试验设计方法.广泛的模拟比较验证了所提方法在小样本情况下可以获得感度分布中位数的准确估计,并且对模型假设和初始参数猜测具有一定的稳健性.当因子效应不是太小的时候,因子筛选方法可以准确地筛选出有显著影响的因子.     

An overview on available models and techniques for the multicriteria reliability problem with emphasis on a potential use in a DSS for this problem type

The paper reviews available models and techniques covering three classes of the multi-criteria reliability problem. These classes include allocation of reliabilities in presence of multiple goals, reliability optimization with several kinds of failures and allocation of resources to optimize multiattribute systems. Optimization techniques are also suggested. The models and techniques are also evaluated with respect to their potential use in a DSS for reliability optimization.     

Hereditary optimal control problems: Numerical method based upon a padé approximation

In this paper, we consider a particular approximation scheme which can be used to solve hereditary optimal control problems. These problems are characterized by variables with a time-delayed argumentx(t – ). In our approximation scheme, we first replace the variable with an augmented statey(t) x(t - ). The two-sided Laplace transform ofy(t) is a product of the Laplace transform ofx(t) and an exponential factor. This factor is approximated by a first-order Padé approximation, and a differential relation fory(t) can be found. The transformed problem, without any time-delayed argument, can then be solved using a gradient algorithm in the usual way. Four problems are solved to illustrate the validity and usefulness of this technique.This research was supported in part by the National Aeronautics and Space Administration under NASA Grant NCC-2-106.