Time-effective and reliable solid-state structure evaluation of selected peracetylated β-maltose derivatives by means of grid search,genetic algorithm and DFT calculations

Efficient solid-state structure evaluation of β-maltose octaacetate (1), methyl β-maltoside heptaacetate (2), and ethyl 1-thio-β-maltoside heptaacetate (3) was performed. The search for the best conformers for 1–3 was conducted in three consecutive steps: grid search, genetic algorithm refinement and DFT study. The use of a genetic algorithm caused a spectacular time shortening of the calculations. The obtained theoretical conformation for 1 resembled its XRD refinement almost perfectly. Although XRD analysis was impossible to perform for 2 and 3 (they form improper crystals), their reliable conformations were obtained. It was proved by the use of ¹³C CP/MAS NMR spectroscopy.     

In‐situ cryocrystallization of 1,2‐dimethyl‐3‐nitrobenzene and 2,4‐dimethyl‐1‐nitrobenzene

The crystal structures of 1,2‐dimethyl‐3‐nitrobenzene, C₈H₉NO₂, and 2,4‐dimethyl‐1‐nitrobenzene, C₈H₉NO₂, which are liquids at room temperature, have been obtained through in‐situ cryocrystallization. Weak C—H...O and also π–π interactions are present in both crystal structures.     

The two-echelon capacitated electric vehicle routing problem with battery swapping stations: Formulation and efficient methodology

In this paper, we present a two-echelon capacitated electric vehicle routing problem with battery swapping stations (2E-EVRP-BSS), which aims to determine the delivery strategy under battery driving range limitations for city logistics. The electric vehicles operating in the different echelons have different load capacities, battery driving ranges, power consumption rates, and battery swapping costs. We propose an integer programming formulation and a hybrid algorithm that combines a column generation and an adaptive large neighborhood search (CG-ALNS) to solve the problem. We conducted extensive computational experiments, demonstrate the applicability of the proposed model, and show the efficiency of the CG-ALNS algorithm. In addition, we explore the interplay between battery driving range and the effectiveness of vehicle emission reduction through sensitivity analysis.     

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In this paper, we put non-concave penalty on the local conditional likelihood. We obtain the oracle property and asymptotic normal distribution property of the parameters in Ising model. With a union band, we obtain the sign consistence for the estimator of parameter matrix, and the convergence speed under the matrix $L_1$ norm. The results of the simulation studies and a real data analysis show that the non-concave penalized estimator has larger sensitivity.     

变邻域模拟退火算法求解速度时变的VRPTW问题

本文在经典的带时间窗的车辆路径问题(VRPTW)的基础上,考虑不同时间段车辆行驶速度不同的情况,研究速度时变的带时间窗车辆路径问题(TDVRPTW),使问题更具实际意义。本文用分段函数表示不同时间段下的车辆行驶速度,并解决了速度时变条件下行驶时间计算的问题。针对模拟退火算法(SA)在求解VRPTW问题时易陷入局部最优解,变邻域搜索算法(VNS)在求解VRPTW问题时收敛速度慢的问题,本文将模拟退火算法以一定概率接受非最优解的思想和变邻域搜索算法系统地改变当前解的邻域结构以拓展搜索范围的思想结合起来,提出了一种改进的算法——变邻域模拟退火算法(SAVN),使算法在退火过程中一陷入局部最优解就改变邻域结构,更换搜索范围,以此提升算法跳出局部最优解的能力,加快收敛速度。通过在仿真实验中将SAVN算法的求解结果与VNS算法、SA算法进行对比,验证了SAVN算法确实能显著提升算法跳出局部最优解的能力。     

Job-shop local-search move evaluation without direct consideration of the criterion’s value

This article focuses on the evaluation of moves for the local search of the job-shop problem with the makespan criterion. We reason that the omnipresent ranking of moves according to their resulting value of a criterion function makes the local search unnecessarily myopic. Consequently, we introduce an alternative evaluation that relies on a surrogate quantity of the move’s potential, which is related to, but not strongly coupled with, the bare criterion. The approach is confirmed by empirical tests, where the proposed evaluator delivers a new upper bound on the well-known benchmark test yn2. The line of the argumentation also shows that by sacrificing accuracy the established makespan estimators unintentionally improve on the move evaluation in comparison to the exact makespan calculation, in contrast to the belief that the reliance on estimation degrades the optimization results.     

A priori policy evaluation and cyclic-order-based simulated annealing for the multi-compartment vehicle routing problem with stochastic demands

We develop methods to estimate and exactly calculate the expected cost of a priori policies for the multi-compartment vehicle routing problem with stochastic demands, an extension of the classical vehicle routing problem where customer demands are uncertain and products must be transported in separate partitions. We incorporate our estimation procedure into a cyclic-order-based simulated annealing algorithm, significantly improving the best-known solution values for a set of benchmark problems. We also extend the updating procedure for a cyclic order’s candidate route set to duration-constrained a priori policies.     

地磁车辆检测器抗邻车位干扰的磁场角度关系分析应用

利用地磁车检器进行停车位检测时,车检器检测轴方向、停车位方向以及地磁场方向之间的角度关系,影响车检器不同轴向的峰值与灵敏度,随意设置会产生邻车位干扰或对磁场扰动的灵敏度低等问题。本研究基于双轴向地磁车检器,在不同停车位方向下,对车检器各个轴向进行测试,找出的最佳指向在保证正向轴高峰值高灵敏度的同时,使侧向轴低峰值低灵敏度,在提高检测精度的同时,减少邻车位干扰问题。研究给出了经验公式,在各地实践中,均得到了良好的效果。     

鱼雷豚跳运动及初始转动角速度选取

鱼雷依靠惯性以一定姿态跃出水面并再次落入水中的过程称之为鱼雷的豚跳运动. 针对鱼雷的豚跳运动需要以零攻角入水, 而鱼雷在空中运动过程中无法控制的问题, 提出了通过构建鱼雷豚跳运动模型并以此为基础控制初始出水转动角速度的解决方法. 附加质量、浮力、浮心、浸湿面积、浸水体积等变量随鱼雷出水姿态、出水过程不同而不同. 在构建鱼雷豚跳运动模型过程中, 充分考虑了各个变化物理量的导数项, 分析了鱼雷水动阻力系数与攻角的关系, 构建了运动模型, 得出鱼雷豚跳运动的规律. 利用优化搜索算法计算出使鱼雷豚跳以零攻角条件入水的初始转动角速度. 仿真结果表明了所建模型及控制初始转动角速度方法的有效性.