基于模拟退火算法的城市物流多目标配送车辆路径优化研究

基于传统模拟退火算法,通过引入记忆函数、结合GIS手段,运用SPSS聚类分析来确定初始化状态种群、多种群并行机制和新状态的产生.依据种群规模采用不同产生算法来改进算法,并将改进算法应用于城市物流中确定的多目标车辆路径优化问题,验证了算法的可行性与实用价值.此外,改进算法分别与传统模拟退火算法和GIS图解法相比较,优化效率和准确率都得到了很大的提高.     

基于价格选择的集配一体化车辆路径问题研究

在家电的集配一体化过程中,回收价格不仅影响企业的回收成本,而且同样影响车辆路径,然而在家电集配过程中回收价格因素一直未能引起足够的重视.为此,以回收价格为出发点,通过定价系统根据产品可再生利用价值与制造商所给的回收价格的差别研究车辆路径优化问题,建立该问题的数学规划模型,同时结合家电集配一体化的实际性和复杂性的要求设计了改进遗传算法.最后,结合算例进行仿真计算,验证了模型与算法的有效性.     

求解车辆路径问题的离散蝙蝠算法

根据车辆路径问题的数学模型,分析了它的具体特征,从而对BA的操作算子又进行了重新定义,设计了求解VRP问题的离散蝙蝠算法,并通过实例测试将离散蝙蝠算法与其他算法进行比较,验证了该算法求解VRP问题的有效性与可行性.     

One-pot synthesis of dihydropyrimidines via eco-friendly phosphorus derivatives catalysis

A straightforward, cost effective and eco-friendly protocol for the Biginelli reaction relying on the use of readily available hypophosphorous acid is presented. The methodology developed displays improvements compared to existing methods, is high-yielding, robust and was applied to a panel of dihydropyrimidines and thio-derivatives with various substituents. Related urea derivatives such as guanidines, benzimidazoles and benzothiazoles also reacted efficiently to afford more complex scaffolds. Thus, this rapid and convenient catalysis allows access to a wide diversity of structures including original biologically relevant heterocycles.     

“On water” ultrasound-assisted one pot efficient synthesis of functionalized 2-oxo-benzo[1,4]oxazines: First application to the synthesis of anticancer indole alkaloid,Cephalandole A

For the first time, an efficient, simple, synthetic green protocol for the one-pot synthesis of functionalized 2-oxo-benzo[1,4]oxazines 24–29 in water under ultrasound irradiation is presented. As compared to conventional methods, the present protocol avoids traditional chromatography and purification steps and furnished the target molecules in excellent yields (upto 98%) with no side products. The methodology was also demonstrated on gram scale synthesis. Moreover, functionalized 2-oxo-quinoxaline analogues 31–33, another class of bio-active heterocyclic scaffolds, were also prepared using this method. For the first time, this protocol was successfully applied in the synthesis of the anticancer indole alkaloid, Cephalandole A 35.     

Consensus problems on networks with free protocol

In the real world, rule makers can only restrict, not completely control the behavior of the governed, while the governed can only choose their behavior patterns under these restrictions. In this paper, we design a new control protocol called free protocol to describe this situation. First, we calculate consensus probabilities based on the information of the interaction networks. Then, sufficient conditions are obtained for all agents converging to a same value with probability one. Finally, numerical simulation results are given to verify the above results.     

A Novel Chemo‐selective Epoxidation across Acrylate Ester: Synthesis of New Water‐Soluble Forskolin Analogues

While removing the TBDMS group from OH protection, a novel epoxidation reaction occurred across acrylate ester attached to a forskolin fragment. Besides spectroscopic data, the epoxide formation was confirmed by ring opening with a secondary amine. This unique epoxidation reaction, to our knowledge, is not known in the literature. This reaction led us to discover a simple deblocking protocol. The epoxide and the desired Michael substrates were used to introduce imidazole into forskolin.     

An exact algorithm for a vehicle routing problem with time windows and multiple use of vehicles

The vehicle routing problem with multiple use of vehicles is a variant of the classical vehicle routing problem. It arises when each vehicle performs several routes during the workday due to strict time limits on route duration (e.g., when perishable goods are transported). The routes are defined over customers with a revenue, a demand and a time window. Given a fixed-size fleet of vehicles, it might not be possible to serve all customers. Thus, the customers must be chosen based on their associated revenue minus the traveling cost to reach them. We introduce a branch-and-price approach to address this problem where lower bounds are computed by solving the linear programming relaxation of a set packing formulation, using column generation. The pricing subproblems are elementary shortest path problems with resource constraints. Computational results are reported on euclidean problems derived from well-known benchmark instances for the vehicle routing problem with time windows.     

Robust and data-driven approaches to call centers

We propose both robust and data-driven approaches to a fluid model of call centers that incorporates random arrival rates with abandonment to determine staff levels and dynamic routing policies. We test the resulting models with real data obtained from the call center of a US bank. Computational results show that the robust fluid model is significantly more tractable as compared to the data-driven one and produces overall better solutions to call centers in most experiments.