基于微粒群算法的农产品物流配送路径优化研究

通过分析农产品物流配送的特点和对车辆调度的影响,对车辆数目不确定的带时间窗的车辆路径问题进行描述,建立起受成本影响、有时限的农产品物流配送路径优化模型,利用复合最优模型微粒群算法对该模型进行求解,并进行案例比较分析。文中所提出的农产品物流配送优化模型对降低农产品物流配送成本,提高农产品物流配送效率具有较好的实用价值。     

自适应粒子群优化算法在车间作业调度问题中的应用

采用粒子群优化算法对该问题进行求解,为了提高算法的求解性能,针对粒子群算法特点,提出了一种自适应的惯性权值来调整算法的搜索空间和一种自适应更新策略来动态地更新粒子的位置.最后通过经典的实例对本文提出的算法进行了检验,结果表明,该改进的粒子群算法在求解车间作业调度问题是有效的.     

基于PSO-SVR模型的煤炭铁路物流需求预测

在煤炭铁路物流需求预测中,存在历史样本量较小和非线性强的特点,从而致使预测精度较低。将支持向量回归机（support vectorreg ression,SVR）与粒子群算法（Particle Swarm Optimization,PSO）相结合,提出适用于小样本量学习的PSO-SVR模型。选取1995-2011年的煤炭铁路货运量及其影响因素作为学习样本,利用粒子群算法对支持向量机参数进行优化,通过训练、测试得到具有良好学习与推广能力的煤炭铁路货运量预测模型。建立BP神经网络模型,并将二者的预测值进行对比,结果表明在解决我国煤炭铁路物流需求预测这种小样本,非线性及高维模式识别问题中PSO-SVR模型预测精度优于BP神经网络模型。     

Pareto efficient allocation of an in-motion wireless charging infrastructure for electric vehicles in a multipath network

Electric vehicles (EV) use an eco-friendly technology that limits the greenhouse gas emissions of the transport sector, but the limited battery capacity and the density of the battery are the major barriers to the widespread adoption of EV. To mitigate this, a good method seems to be the innovative wireless charging technology called ‘On-Line EV (OLEV)’, which is a contactless electric power transfer technology. This EV technology has the potential to charge the vehicle’s battery dynamically while the vehicle is in motion. This system helps to reduce not only the size of the battery but also its cost, and it also contributes to extending the driving range before the EV has to stop. The high cost of this technology requires an optimal location of the infrastructure along the route. For this reason, the objective of this paper is to study the problem of the location of the wireless charging infrastructure in a transport network composed of multiple routes between the origin and the destination. To find a strategic solution to this problem, we first and foremost propose a nonlinear integer programming solution to reach a compromise between the cost of the battery, which is related to its capacity, and the cost of installing the power transmitters, while maintaining the quality of the vehicle’s routing. Second, we adapt the multi-objective particle swarm optimization (MPSO) approach to our problem, as the particles were robust in solving nonlinear optimization problems. Since we have a multi-objective problem with two binary variables, we combine the binary and discrete versions of the particle swarm optimization approach with the multi-objective one. The port of Le Havre is presented as a case study to illustrate the proposed methodology. The results are analyzed and discussed in order to point out the efficiency of our resolution method.     

基于PSO-SAS的联合侦察任务规划

针对联合侦察筹划中任务规划阶段机动侦察平台阵位与路线确定困难的问题,提出了一种基于粒子群优化-稀疏A星(Particle Swarm Optimization—Sparse A-star,PSO-SAS)算法的规划方法。该方法综合考虑侦察装备机动性能以及敌火力威胁、地形等因素,在侦察阵位规划上,建立了阵位综合评估模型,并利用粒子群算法进行阵位寻优;在路线规划上,采用稀疏A*算法进行航迹规划,通过将机动性能、安全距离、路程等约束引入搜索过程,缩短最优路线的计算时间。仿真试验验证了所提方法生成的侦察阵位和路线能够满足侦察任务要求。     

基于粒子群算法下的交叉口信号配时优化

为了合理地优化交叉口信号配时,通过分析交叉口的评价指标,建立了以车辆的平均延误、停车次数最小、交叉口整体通行能力最大、各相位有效绿灯时间和交叉口周期时长作为约束条件的数学模型。并通过改进前人研究基础上的动态加权系数,将多目标的非线性优化问题转化为单一目标的非线性规划问题,为了得出更科学稳定的解,提出了改善粒子群算法系统稳定性的2种方法,并将其与粒子群算法结合起来。然后以Matlab为求解工具,结合临邑市某一交叉口实例进行求解分析。最后的结果表明,在使用改进后的粒子群算法进行优化后交叉口通行能力较之现状提升了9%,延误下降了28%,停车次数下降了9%,且各项优化结果均优于Webster,改进后的算法在程序中运行300代,到216代才开始收敛,而未改进的算法稳定性较差,优化结果和收敛曲线则随着实验次数的变化而变化,最后的结论证明了该算法和模型的可靠性。     

Dissecting interbank risk using basis swap spreads

This paper analyses interbank risk using the information content of basis swap (BS) spreads, floating-to-floating interest rate swaps whose payments are associated with euro deposit rates for alternative tenors. To identify the impact of shocks affecting interbank risk, we propose an empirical model that decomposes BS quotes into their expected and unexpected components. These unobservable constituents of BS spreads are estimated by solving a signal extraction problem using a particle filter. We find that expected components covariate with aggregate liquidity and risk aversion while systemic risk arises as the main driver behind unexpected fluctuations. Our empirical findings suggest that macroprudential analysis emerges as a key device to ease asset pricing in a new multi-curve scenario.     

激光散射法测定那他霉素粒度研究

为了减少那他霉素原料药各批次之间的粒度差异,提高其制剂产品质量和疗效稳定性,建立了一种激光散射法测定那他霉素粒度的方法。采用Mastersizer 2000激光粒度仪干法测定那他霉素粒度,分别对分散气压、振动进样速度及测量时间等关键测定参数进行了优选,并对本方法的重复性、中间精密度和耐用性进行了验证。结果表明：在分散气压为0.30 MPa、振动进样速度为45%、背景和测量扫描时间为10 s、样品折射率为1.50、颗粒吸收率为0.1、遮光度范围为0.5%~5%等条件下,所测样品的RSD均小于2.5%。方法学各项验证指标相对标准偏差均符合要求。所建立的测定那他霉素粒度的激光散射法精密度较高、重复性好,能够有效控制原料药的批间差异,可为生产出安全、有效、均一、稳定的制剂产品提供保障和参考。[HJ4mm]     

固体自燃温度测定结果准确性的影响因素研究

为提升固体自燃温度测定方法的科学性和适用性,以BMC模塑料和木炭颗粒作为研究对象,通过测定多组固体自燃温度,对比分析了反应类型、颗粒大小和装填密度分别对固体自燃温度测定结果的影响情况.结果表明:1)BMC模塑料的固化反应放出的热量对固体自燃温度测定结果的判定具有干扰作用;2)固体自燃温度随固体颗粒粒径减小而升高,但升高...     

STOCHASTIC LOCAL INTENSITY LOSS MODELS WITH INTERACTING PARTICLE SYSTEMS

It is well known from the work of Schönbucher that the marginal laws of a loss process can be matched by a unit increasing time inhomogeneous Markov process, whose deterministic jump intensity is called local intensity. The stochastic local intensity (SLI) models such as the one proposed by Arnsdorf and Halperin allow to get a stochastic jump intensity while keeping the same marginal laws. These models involve a nonlinear stochastic differential equation (SDE) with jumps. The first contribution of this paper is to prove the existence and uniqueness of such processes. This is made by means of an interacting particle system, whose convergence rate toward the nonlinear SDE is analyzed. Second, this approach provides a powerful way to compute pathwise expectations with the SLI model: we show that the computational cost is roughly the same as a crude Monte Carlo algorithm for standard SDEs.