“仓店一体化”模式下订单拣选与配送集成调度优化

针对“仓店一体化”模式下提供限时送达服务的新零售仓店,研究多拣货员、多客户、配送方式为带限时送达约束的路径优化分批配送情形下的订单拣选与配送集成调度问题。以最小化订单最大履行时间和配送成本为目标,构建了混合整数非线性规划模型,并设计两阶段启发式算法(H-2)进行求解,最后通过数值实验对算法进行验证与分析。数值实验结果表明,H-2具有较高的求解质量;相较于传统调度算法(TS)在效率提升、资源节约以及客户满意度提高方面具有更优的表现,进而为新零售仓店管理者提供决策支持。     

复杂背景下小目标恒虚警检测技术研究

为了实现复杂背景下的弱小目标恒虚警检测,提出了一种基于CEM算法的恒虚警探测算法.在分析CEM算法滤波处理结果分布规律的基础上,采用TM-CFAR方法选择恒虚警探测门限,并结合形态学方法克服了背景虚警概率曲线中的拖尾现象.以ETM数据为例进行了计算机模拟.结果表明,该方法在信干比为-5dB和虚警率为10-4的条件下,可以有效地检测出被探测目标.     

正负交替反转法解析电子衍射相位问题

与X射线晶体学中存在的相位问题类似,在电子衍射中也存在相位问题:在电子衍射实验中只能收集到衍射强度而丢失了相位.最近,衍射重构成像方法(diffractive imaging),即直接从衍射重构出晶体结构的方法,从理论和实验都有了重大进展.从理论上,人们提出和发展许多有效的相位解析方法.从实验上,高强度的X射线源,场发射电子枪以及高灵敏度的记录媒介的发展都对此有贡献.直接从衍射重构出晶体结构有许多的优点:首先在重构像中,物镜球差的影响很小.这是由于物镜传递函数对衍射强度的影响远远小于对相位的影响;其次,从同一晶体收集的电子衍射有更多的高阶衍射斑,使得衍射重构能得到较高的分辨率(小于0.1 nm);同时,在同样辐射条件下晶体的电子衍射比其高分辨像具有更高的信噪比.这对于用电镜解析对辐射损伤敏感的有机物和生物蛋白晶体是有用的.本文叙述了一个解决电子衍射相位的新方法.在本文的程序中,同时使用了Oszlányi和Süto提出的正负交替反转法(charge-flipping algorithm)和Fienup的重构方法(hybrid input-output algorithm).作者用模拟数据来验证该方法的有效性.在程序中输入计算的运动学电子衍射强度,模拟晶体的二维静电势场分布能被重构出来.使用归一化结构因子可以提高正空间的重构像衬度;这对解决相位问题是有利的.使用Fienup的重构方法可以有效地解决由局域最小值而引起程序停滞问题.在正负交替反转法中通常会有停滞问题而不能找到全局最小值.正负交替反转法会逐步地在正空间中产生较大的零值电势区域,从而减小了正空间中未知数的数目.当未知数数目小于或等于从傅立叶变换建立起来的等式数目时,晶体的相位就可以解决了.     

双层PLS算法及其在近红外光谱分析中的应用

针对近红外光谱数据局部效应显著,变量个数多,且彼此间常存在严重的复共线性,并与样品组分含量呈非线性关系,构建了一种双层非线性偏最小二乘回归 (DNPLSR)算法。它将非线性回归和偏最小二 乘(PLS)相结合,先在外层由PLS从样本数据中提取成分,并实现每对成分间的非线性映射,再在内层实施PLS算法,将外层因变量成分的拟合误差反馈计算转换权向量的增量,进一步修正转换权向量,以使外层所提取的成分对因变量具有更优的解释能力。最后,将该法应用于80个谷物样品的水组分含量与其近红外光谱的定量关系建模,效果良好,显示出很强的学习能力,所建模型的预报性能也优于其他方法。     

Gain characteristics and optimization of dual-pump fiber optical parametric amplifier using two-section highly nonlinear fibers

In this paper the gain characteristics of two-pump fiber optical parametric amplifiers (FOPA) with two-section highly nonlinear fibers are analyzed numerically and the parameters of the fibers are optimized to reach broad and flat gain spectra using genetic algorithm. Different from the previous methods, here the space between two pump wavelengths and the parameter β₄ of the fibers are included as a pivotal factor in the optimization. The numerical simulation shows that using two-section practical high nonlinear fibers, the amplifier may reach 110 nm bandwidth covering 1495–1605 nm with 10.5 dB average gain and gain ripple of 0.17 dB, when the total pump power is 1 W.     

ZnO thin film characterization by X-ray reflectivity optimization using genetic algorithm and Fourier transformation

Zinc oxide (ZnO) thin film was fabricated by sol-gel spin coating method on glass substrate. X-ray reflectivity (XRR) and its optimization have been used for characterization and extracting physical parameters of the film. Genetic algorithm (GA) has been applied for this optimization process. The model independent information was needed to establish data analyzing process for X-ray reflectivity before optimization process. Independent information was exploited from Fourier transform of Fresnel reflectivity normalized X-ray reflectivity. This Fourier transformation (Auto Correlation Function) yields thickness of each coated layer on substrate. This information is a keynote for constructing optimization process. Specular X-ray reflectivity optimization yields structural parameters such as thickness, roughness of surface and interface and electron density profile of the film. Acceptable agreement exists between results obtained from Fourier transformation and X-ray reflectivity fitting.     

Predictor-corrector algorithm for solvingP *(κ)-matrix LCP from arbitrary positive starting points

A new predictor-corrector algorithm is proposed for solvingP _*(κ)-matrix linear complementarity problems. If the problem is solvable, then the algorithm converges from an arbitrary positive starting point (x ⁰,s ⁰). The computational complexity of the algorithm depends on the quality of the starting point. If the starting point is feasible or close to being feasible, it has -iteration complexity, whereρ ₀ is the ratio of the smallest and average coordinate ofX ⁰ s ⁰. With appropriate initialization, a modified version of the algorithm terminates in O((1+κ)²(n/ρ ₀)L) steps either by finding a solution or by determining that the problem has no solution in a predetermined, arbitrarily large, region. The algorithm is quadratically convergent for problems having a strictly complementary solution. We also propose an extension of a recent algorithm of Mizuno toP _*(κ)-matrix linear complementarity problems such that it can start from arbitrary positive points and has superlinear convergence without a strictly complementary condition. The work of this author was supported in part by NSF, Grant DMS 9305760 and by an Oberman fellowship from the University of Iowa Center for Advanced Studies.     

Correctness proof of an in-place permutation

The correctness of an in-place permutation algorithm is proved. The algorithm exchanges elements belonging to a permutation cycle. A suitable assertion is constructed from which the correctness can be deduced after completion of the algorithm.An in-place rectangular matrix transposition algorithm is given as an example.     

Set to set broadcasting in communication networks

Suppose G = (V,E) is a graph whose vertices represent people and edges represent telephone lines between pairs of people. Each person knows a unique message and is ignorant of the messages of other people at the beginning. These messages are then spread by telephone calls. In each call, two people exchange all information they have so far in exactly one unit of time. Suppose A and B are two nonempty subsets of V. The main purpose of this paper is to study the minimum number b(A,B,G) of telephone calls by which A broadcasts to B; and the minimum time t(A,B,G) such that A broadcasts to B. In particular, we give an exact formula for b(A,B,K_n) and linear-time algorithms for computing b(A,B,T) and t(A,B,T) of a tree T.