A solution procedure for the discrete time, cost and quality tradeoff problem using electromagnetic scatter search

Decisions concerning a project’s expedition, traditionally involved considerations regarding time and cost tradeoff. It was recently suggested that the quality of a project should also be taken into considerations. In this paper, we propose a meta-heuristic solution procedure for the discrete time, cost and quality tradeoff problem. This problem involves the scheduling of project activities in order to minimize the total cost of the project while maximizing the quality of the project and also meeting a given deadline. We apply a so called electromagnetic scatter search to solve this problem. In this process, we initially generate a population of feasible solutions. In so doing, we use frequency memory to well sample the feasible region. A number of these solutions are then selected and improved locally. The improved solutions are then combined to generate new set of solutions. The combination process utilizes attraction–repulsion mechanisms borrowed from the electromagnetism theory. The whole process is stopped when no significant improvement in the set of solutions are observed. The validity of the proposed solution procedure is demonstrated, and its applicability is tested on a randomly generated large and complex problem having 19,900 activities.     

基于战略顾客行为的最优定价与容量选择模型

研究了当市场中同时存在战略顾客和短视顾客时零售商的最优定价与容量选择问题。零售商在正常销售阶段和出清销售阶段制定不同的销售价格,同时通过容量选择影响战略顾客的购买行为,而战略顾客则根据零售商的定价和容量选择确定最优购买时机。分别分析了零售商在无限容量时的定价决策、固定价格时的容量选择、固定容量时的定价决策以及有限容量下的定价与容量选择四种情形。研究结果表明,零售商在无容量限制时的最优定价决策是制定两阶段定价策略,在固定价格时的最优容量选择依赖于模型的参数,而当零售商的容量固定时,部分满足出清销售阶段的顾客需求始终优于完全满足出清销售阶段的顾客需求。     

Optimal DB-PAYGO pension management towards a habitual contribution rate

In this paper, we propose a new objective function, which reflects the costs of unstable contribution risk and discontinuity risk in DB-PAYGO pension system. The problem is to minimize the quadratic deviation between the actual contribution rate and a habitual target and the quadratic proportional deviation of the pension accumulation. A modified non-negative constraint of the contribution rate is added, which together with a stochastic habitual target process, causes difficulty in solving the minimization problem by Lagrange dual method. The results are split into two cases which depend on the habit-adjusted adequacy of the pension budget. In the inadequate case, the optimal contribution rate reveals a hump shape curve with respect to time, which is different from the exponential growth curve of the model with a fixed target. By moderately raising the contribution rate in the initial phase, it helps to increase the accumulation and reduce the contribution burden of the follow-up policyholders. Notably, the hump shape curve is a more practical policy, because of that the exponential growth curve raises anxiety about the unlimited growth of the contribution rate and harms the confidence in the sustainability of the pension fund. We also study the impacts of the certain trend in demography, and the uncertain fluctuations in salary and investment on the optimal control policies.     

持续推进人才培养基地建设实现化学创新人才高质量培养

吉林大学化学学科自建立伊始,以创新型化学及相关交叉学科人才为根本目标,历经1993年开始的国家理科基础科学研究和教学人才培养基地建设、2009年开始的“基础学科拔尖学生培养试验计划”实施、2020年的“基础学科拔尖学生培养计划2.0基地”建设与基础学科招生改革试点(强基计划)的实施,通过近30年化学基地的持续建设,形成了具有吉大特色的以“厚基础、强能力、会创新”的化学创新人才培养模式。围绕基地持续建设过程中如何针对学科发展以及学生知识结构的变化,不断推进拔尖班、强基班的教学管理模式与课程体系建设,打造高水平师资队伍、加大优质课程建设、探索国家化培养模式等进行介绍。     

Spatially resolved characterization of PEFCs using simultaneously neutron radiography and locally resolved impedance spectroscopy

A method for performing neutron radiography and locally resolved impedance spectroscopy simultaneously in situ in an operating polymer electrolyte fuel cell (PEFC) is presented. The new method provides concurrently spatially resolved information about the local cell performance, the locally limiting processes, and the liquid water distribution. Information about the impact of water on cell performance and limiting processes can be gained in situ on a local scale in an operating PEFC. The method was applied to a PEFC operated on pure H₂/O₂ in co-flow mode under low humidity operating conditions. The results show that in co-flow mode strong flooding and severe drying can occur at the very same time in different sections of a PEFC.     

液冷薄片构型激光器及其热管理技术

为了解决增益介质的热效应问题,提出了一种浸没式构型液冷激光器方案,该构型激光器在10Hz重复抽运频率下,获得了615mJ的能量输出,光光转换效率为21%,斜率效率为23%.基于流体力学和热力学原理,建立了激光器增益区流场的热-流-固耦合模型,利用软件模拟和有限元分析法,研究了在不同流速、泵浦功率条件下,整个增益区的温度场、速度场的分布特性;并基于增益区温度场的分布,分析了液冷条件下通过增益区的激光波前畸变特性.结果表明,增益介质的最大光程差为0.7666λ,冷却液最大光程差为-4.7331λ,说明该构型激光器有着良好的热管理性能.     

基于瑞利熵的多无源传感器数据关联算法

针对当前多无源传感器数据关联算法构造关联代价时,未考虑位置估计不确定性所引入的误差,提出一种基于位置估计不确定性的被动传感器数据关联算法。首先通过量测与伪量测概率密度函数之间的瑞利熵构建关联代价函数,以准确描述两个相似的概率密度函数之间差异,然后通过具体实验测试本文算法的有效性和优越性。实验结果表明,相对于当前经典的数据关联算法,本文算法提高了数据关联的正确率和速度,具有更高的实际应用价值。     

BoneRoute: An Adaptive Memory-Based Method for Effective Fleet Management

This paper presents an adaptive memory-based method for solving the Capacitated Vehicle Routing Problem (CVRP), called BoneRoute. The CVRP deals with the problem of finding the optimal sequence of deliveries conducted by a fleet of homogeneous vehicles, based at one depot, to serve a set of customers. The computational performance of the BoneRoute was found to be very efficient, producing high quality solutions over two sets of well known case studies examined.     

基于Web技术的网络拓扑图生成方法的研究

综合采用提取路由表和地址转发表的方法，对网络逻辑拓扑结构和物理拓扑结构进行自动探索，提出了用于优化显示网络拓扑图的一种显示算法，采用Java技术实现了基于Web的网络拓扑图，并对在实现过程中遇到的问题进行了探讨。试验结果表明，由此生成的网络拓扑图准确、美观、能够实现跨平台和跨区域的管理。     

基于动态混沌映射的三维加密正交频分复用无源光网络

提出了一种基于混沌映射的三维加密正交频分复用无源光网络保密通信系统.该系统通过相关性检测锁定收发端混沌系统参数,实现收发双方混沌系统同步;并利用同步混沌系统生成密钥,实现符号扰动以及二重子载波加密.该加密方案的密钥空间超过10~(86),能够有效对抗穷举攻击.实验实现了13.3 Gb/s基于64进制正交幅度调制的加密正交频分复用信号在25 km标准单模光纤中的传输,并完成了信息的有效解密.