关键词： Closed-loop supply chain network design   Modified priority-based encoding   Uncertainty   Whale optimization algorithm  

摘要： The closed-loop supply chain (CLSC) management as one of the most significant management issues has been increasingly spotlighted by the government, companies and customers, over the past years. The primary reasons for this growing attention mainly down to the governments-driven and environmental related regulations which has caused the overall supply cost to reduce while enhancing the customer satisfaction. Thereby, in the present study, efforts have been made to propose a facility location/allocation model for a multi-echelon multi-product multi-period CLSC network under shortage, uncertainty, and discount on the purchase of raw materials. To design the network, a mixed-integer nonlinear programming (MINLP) model capable of reducing total costs of network is proposed. Moreover, the model is developed using a robust fuzzy programming (RFP) to investigate the effects of uncertainty parameters including customer demand, fraction of returned products, transportation costs, the price of raw materials, and shortage costs. As the developed model was NP-hard, a novel whale optimization algorithm (WOA) aimed at minimizing the network total costs with application of a modified priority-based encoding procedure is proposed. To validate the model and effectiveness of the proposed algorithm, some quantitative experiments were designed and solved by an optimization solver package and the proposed algorithm. Comparison of the outcomes provided by the proposed algorithm and exact solution is indicative of high quality performance of the applied algorithm to find a near-optimal solution within the reasonable computational time. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Admixture   Neighbor-joining   Phylogenetics   Rogue taxon  

摘要： The neighbor-joining algorithm for phylogenetic inference (NJ) has been seen to have three specific properties when applied to distance matrices that contain an admixed taxon: (1) antecedence of clustering, in which the admixed taxon agglomerates with one of its source taxa before the two source taxa agglomerate with each other;(2) intermediacy of distances, in which the distance on an inferred NJ tree between an admixed taxon and either of its source taxa is smaller than the distance between the two source taxa;and (3) intermediacy of path lengths, in which the number of edges separating the admixed taxon and either of its source taxa is less than or equal to the number of edges between the source taxa. We examine the behavior of neighbor-joining on distance matrices containing an admixed group, investigating the occurrence of antecedence of clustering, intermediacy of distances, and intermediacy of path lengths. We first mathematically predict the frequency with which the properties are satisfied for a labeled unrooted binary tree selected uniformly at random in the absence of admixture. We then introduce a taxon constructed by a linear admixture of distances from two source taxa, examining three admixture scenarios by simulation: a model in which distance matrices are chosen at random, a model in which an admixed taxon is added to a set of taxa that reflect treelike evolution, and a model that introduces a perturbation of the treelike scenario. In contrast to previous conjectures, we observe that the three properties are sometimes violated by distance matrices that include an admixed taxon. However, we also find that they are satisfied more often than is expected by chance when the distance matrix contains an admixed taxon, especially when evolution among the non-admixed taxa is treelike. The results contribute to a deeper understanding of the nature of evolutionary trees constructed from data that do not necessarily reflect a treelike evolutionary process.

关键词： Cobalt oxide   basin-hoping Monte Carlo   DFT  

摘要： The structural, electronic and magnetic properties of the neutral and cationic cobalt oxide clusters (CoO)(n)(q) (n = 3 - 10, q = 0, +1) have been studied using a modified basin-hopping Monte Carlo (BHMC) algorithm refined by spin-polarized DFT. A systematic search of global minimum structures predicts new global minima of (CoO)(9)(0/+) and reproduced other minima that are in excellent agreement with previous works. For most low-spin and high-spin states, the structural transition from planar-like to compact structure occurs at (CoO)(5)(0/+), which is in contrast with the general notion that the structural changes at (CoO)(6)(0/+). Supported by the results of the binding energy, second-order total energy difference, chemical hardness, chemical potential and HOMO-LUMO gap confirms the stability of (CoO)(4). Results of the spin magnetic moments for the global minima show that (CoO)(4) and (CoO)(8) spin configurations exhibit a fully antiferromagnetic (AFM) ordering, while (CoO)(9) spin displays the highest ferromagnetic (FM) ordering. Interestingly, elongation of Co-Co bond in (COO)(4) causes O being polarized by the neighboring Co atoms that accordingly follows the Goodenough-Kanamori-Anderson rule of FM super-exchange coupling for the Co-O-Co structural rearrangement to 90 degrees (D-4h structure) in order to accommodate the spin magnetic ordering changes. This rearrangement is a result of the valence band being shifted away from the Fermi level to lower energy causing high population of the spin-up density of state and leading to the asymmetrical polarization of the whole (CoO)(4)nq structure. As far as the dissociation energy surfaces are concerned, the first ever such surfaces are constructed corresponding to (CoO)(n)(q) -> (CoO)(m)(q) (CoO)((n-m)), which identify a complete dissociation pathway linking the cationic and neutral clusters and finally confirm (CoO)(4)(0/+) as the most stable cluster compared to the rest.

关键词： radiofrequency   Herbal Medicine   traceability   Vasoactive Intestinal Peptide   Paris polyphylla   Variance  

摘要： Paris polyphylla has been used by multiple nationalities as a traditional herb medicine to treat diseases in different regions of China. Since Paris quality is influenced by geographical regions, a fast and effective geographical traceability method is necessary. In our study, the geographical origin discrimination of 789 P. yunnanensis species from central, western, northwest, southeast and southwest Yunnan with 3rd to 8th cultivation years was carried out by chemometric of partial least squares discriminant analysis (PLS-DA), random forest (RF) and hierarchical cluster analysis (HCA) combined with attenuated total reflection-Fourier transform mid infrared (ATR-FTMIR). The results indicated that principal component analysis (PCA) was successfully used as an exploration data analysis method to remove outliers. Additionally, classification ability of PLS-DA model, established by variable importance for the projection (VIP), was similar to that of PLS-DA model, which indicated that raw ATR-FTMIR spectra contained abundant redundant information useless for classifying samples. For each model, the range of VIP values of PLS-DA is wider than the range of the important variables of RF, and PLS-DA was more time-efficient and high-ability than RF model. Besides, the geographical origin PLS-DA classification model with all collected samples was used to verify the results with accuracy rates of calibration set and validation set of 98.34% and 93.78%, respectively. HCA verified that the impact of geographical origin on P. yunnanensis characteristics is greater than that of the number of cultivation years. In short, PLS-DA model can assure the accuracy and limit time for identification analysis of cultivated P. yunnanensis quality assessment from different geographical origins.

关键词： 数学文化   算法   人类文明   中学数学   学习   领悟  

摘要： 数学作为一种先进的文化,对人类文明的进程起着不可磨灭的作用。近年来,数学文化不断地渗透在中学数学的学习中,本文以算法为案例进行分析,希望对大家了解并领悟数学文化试题能有所帮助。

关键词： 算法   实验教学   高中数学   优课   策略  

摘要： 算法是高中数学的重要内容,在算法的教学过程中结合上机实验既是创新教学之举,也与"一师一优课,一课一名师"活动中的教学设计要求相吻合.在相关优课的开发过程中,应该注意自主性、探究性、互动性、合作性和评价性等策略.

关键词： 装配零件集   装配约束件   矩阵算法   约束矩阵   线性递推算法   WMS数学模型  

摘要： 为了获得产品的最优自动装配顺序,根据自动装配原理提出装配零件集和装配约束件的概念,运用矩阵算法和线性递推算法构建装配顺序的WMS数学模型。依据产品装配结构特征和装配约束件约束特征分别构建装配关联矩阵和装配约束矩阵,进而获得理论装配工艺数和顺序序列。运用层次分析法确定装配因素的影响权重系数和对各影响因素值进行无量纲化处理,获得产品的装配顺序评价模型。运用此模型即可便捷地确定产品的最优自动装配顺序。以一自动-手动水龙头装配为例进行实证研究。结果表明上述理论方法可行和实用。

关键词： 空间分辨力   单光子发射型电子计算机断层扫描仪(SPECT)   空间分辨性能  

摘要： 目的:分析单光子发射型电子计算机断层扫描仪(SPECT)空间分辨性能,为制定SPECT性能检测标准时数学函数算法的选取提供参考。方法:使用SPECT通用检测模体获取固有空间分辨力、系统空间分辨力及全身平面空间分辨力3个性能参数的医学数字成像和通信(DICOM)图像,对3个性能参数随机获取10次测量数据,分别采取抛物线算法和高斯算法对数据进行拟合计算测量,并分析两种数学函数算法结果的差异。结果:所获SPECT的3个性能参数高斯算法拟合相关系数平方(R^2)值为0.974～0.999;SPECT固有空间分辨力、系统空间分辨力和全身平面空间分辨力的检验P值分别为0.0001、0.057和0.075。结论:对于SPECT空间分辨性能的分析可采用抛物线法进行分析,对于系统空间分辨力应该采集256×256矩阵的数据。

关键词： 探究   算法   算理   计算能力  

摘要： 数学计算能力的培养,不仅是小学数学教学的重要内容,也是继续学习数学和其他自然学科的基础。在“两位数减一位数退位减法”的设计与教学过程中,教师让学生摆小棒,借助计数器理解减法拆、借过程中计数单位的变化,明白“借一当十”这一算理;借助已有减法的经验,自主探索两位数减一位数的笔算过程,在对比几种不同计算的过程中掌握算法,培养学生的计算能力。