实时需求下的带时间窗移动充电车在线调度算法

在双碳背景下,移动充电车作为新型充电设施,能够缓解电动车保有量迅速增长带来的充电压力。然而成本高、效益低等问题阻碍了移动充电车的进一步发展。本文针对移动充电车只有在用户发出充电请求时,才能获知充电需求信息的特点,且需求带有时间窗要求的情形,提出实时需求下的带时间窗移动充电车调度问题,以总时间成本最小为目标,采用在线理论与方法,建立优化模型并设计在线算法;给出了不同情形下的调度方案,计算方案的竞争比,并进行对比分析;最后通过数值算例验证了在线算法的可行性和有效性。研究结果表明,用户发出的实时充电需求数量越大、最大单位惩罚时间成本系数越小,在线算法的执行效果越好。本文的模型和在线调度算法可以有效解决实时需求下的带时间窗移动充电车调度优化问题,提高移动充电车的充电效率,平衡充电供需。     

TRAJECTORY DESIGN OF THE GALAXY SETTLEMENT-SUMMARY OF THE CHAMPION TEAM TO THE 10TH GLOBAL TRAJECTORY OPTIMIZATION COMPETITION

由美国喷气推进实验室(Jet Propulsion Laboratory, JPL)主办的第十届国际空间轨道设计大赛于2019 年6月落下帷幕,中国队伍首次在该赛事中夺冠。本届比赛在历史上首次以科幻任务为背景,需设计对银河系10万颗恒星的最优移民轨道方案。本文介绍了银河系移民的任务要求、引力模型和飞船机动模型,着重分析了赛题的评价指标。引入了树结构来表示移民方案,并对移民树初始分布的选取方法进行了描述,再对比介绍了正向和反向两种移民树生成策略。同时对竞赛中使用的移民树局部优化和拓扑重构等方法进行了简要说明,并在银河系星图中以树结构展示了冠军方案。对本届竞赛的意义进行了总结,得到了一些有益的启发。     

偶氮材料中双波长共存的图象研究

测量了偶氮材料MO/PVA和EO/PVA的光致双折射,其值约为δ_n=2.7×10^-3.在同偏振态两路简并四波混频光同时作用于样品同一区域的条件下,研究了该材料的双波长共存特性,记录了光点存储和图象存储,并分析了双波长共存的竞争机制.     

Solution Properties of Aluminum and Titanium Complexes with o-Chlorophenylfluorone and Competition Coordination for Selective Determination of Trace Amounts of Titanium

 The competition coordination for selective determination (CCSD) is described and the complexations of Ti(IV) and Al(III) with o-chlorophenylfluorone (o-CPF) is studied at pH 4.5 in presence of Triton X-100. The determination of equilibrium constants of the complexes was made by the spectral correction technique in place of ordinary spectrophotometry. The complexes are formed as [Al(o-CPF)₃]³⁻ and [Ti(o-CPF)₃]²⁻ and their stepwise and cumulative stability constants are calculated. Trace amounts of Ti can substitute Al from its o-CPF complex and the competition coordination has been used in the quantitative determination of Ti in water samples with satisfactory results. Received July 14, 2000. Revision June 25, 2001.     

The competition numbers of complete tripartite graphs

For a graph G, it is known to be a hard problem to compute the competition number k(G) of the graph G in general. In this paper, we give an explicit formula for the competition numbers of complete tripartite graphs.     

复杂生态系统的模糊数学模型

生态系统是一个复杂的大系统，很多重要的生态学理论问题都是以生态位(niche)和生物群落概念为基础的。本文将生态位和群落抽象出来，看作是一个耗散结构。建立生态系统中基本概念的量化算子，利用系统模糊分析理论给出具有明确生物意义的生态位和群落的Fuzzy数学模型。并以此讨论生态系统中其他相关概念的数学模型、群落的水平和垂直格局及物种间在资源、斑块、时间三维模糊集上的互惠，共处和竞争关系。初步构建起复杂生态大系统的数学理论框架。     

全国实验技能大赛对大学生综合素质培养的推动作用

全国实验技能大赛是大学生综合素质培养的一个重要途径.以2013年全国金相大赛为例,详述了大赛的组织方法和实施过程.认为全国实验技能大赛对提高大学生学习积极性和学习动力具有重要的推进作用,对强化学生所学知识的认识具有积极的促进作用,对增强学生的综合素质具有较好的推动作用.     

Discreteness inducing coexistence

Consider two species that diffuse through space. Consider further that they differ only in initial densities and, possibly, in diffusion constants. Otherwise they are identical. What happens if they compete with each other in the same environment? What is the influence of the discrete nature of the interactions on the final destination? And what are the influence of diffusion and additive fluctuations corresponding to random migration and immigration of individuals? This paper aims to answer these questions for a particular competition model that incorporates intra and interspecific competition between the species. Based on mean field theory, the model has a stationary state dependent on the initial density conditions. We investigate how this initial density dependence is affected by the presence of demographic multiplicative noise and additive noise in space and time. There are three main conclusions: (1) Additive noise favors denser populations at the expense of the less dense, ratifying the competitive exclusion principle. (2) Demographic noise, on the other hand, favors less dense populations at the expense of the denser ones, inducing equal densities at the quasi-stationary state, violating the aforementioned principle. (3) The slower species always suffers the more deleterious effects of statistical fluctuations in a homogeneous medium.     

The Intra-cavity Mode Competition and Laser Absorption Spectroscopy with CO2 Laser

A mathematical model is developed for analysis the dynamics of an intra-cavity laser spectroscopy and mode competition using the CO₂ laser as the coherent source. The governing equations of system are derived and effect of the absorbing material on the laser modes, as a time-dependent term is considered. Thus, the application of the CO₂ laser for intra-cavity laser spectroscopy with considering an inhomogeneous medium and effect of the absorbing material is investigated.     

Competition for cores in remanufacturing

We study competition between an original equipment manufacturer (OEM) and an independently operating remanufacturer (IO). Different from the existing literature, the OEM and IO compete not only for selling their products but also for collecting returned products (cores) through their acquisition prices. We consider a two-period model with manufacturing by the OEM in the first period, and manufacturing as well as remanufacturing in the second period. We find the optimal policies for both players by establishing a Nash equilibrium in the second period, and then determine the optimal manufacturing decision for the OEM in the first period. This leads to a number of managerial insights. One interesting result is that the acquisition price of the OEM only depends on its own cost structure, and not on the acquisition price of the IO. Further insights are obtained from a numerical investigation. We find that when the cost benefits of remanufacturing diminishes and the IO has more chance to collect the available cores, the OEM manufactures less in the first period as the market in the second period gets larger to protect its market share. Finally, we consider the case where consumers have lower willingness to pay for the remanufactured products and find that in that case remanufacturing becomes less profitable overall.