基于FLEXSIM的通用弹药配送中心仿真研究

通用弹药配送。是指在平时或战时状态下开展的军事物流活动。首先讨论了建立军事物流中心的必要性,分析了弹药配送中心的工作流程和概念模型．基于FIEXSIM建立了弹药配送系统仿真模型．重点研究配送中心的最大存储和订货条件（最小库存）对配送中心成本的影响。这对于配送中心的规划建设具有十分重要的参考价值。     

基于Witness的供应链系统的仿真设计与改善

文章介绍了供应链中的“牛鞭效应”以及Witness的基本应用,讨论了在供应链系统中利用Witness软件进行仿真的方法．采用了由钢铁公司、钢材服务中心、部件生产商和汽车厂所组成的供应链结构进行仿真,整个供应链和供应链上各节点的订货提前期和运输时间是所介绍的模型中的主要供应链绩效指标。通过模型的运行结果分析出供应链系统中的“瓶颈”和导致“牛鞭效应”出现的原因．从而提出缓解牛鞭效应的对策,并通过设置模型中的参数对供应链系统进行改善,以缓解“牛鞭效应”．     

基于AGENT的装备供应链仿真模型设计与实现

通过计算机对装备供应链系统进行仿真,可以获得许多宝贵的数据,减少相应的风险,增强决策的科学性,提高战时装备供应保障的科学化、现代化水平。文章构建了基于Agent的装备供应链仿真模型,利用Swarm仿真平台描述了Agent仿真模型,并运用Java语言,实现了Swarm平台下的Agent的交互。     

Sensitivity estimates for portfolio credit derivatives using Monte Carlo

Portfolio credit derivatives are contracts that are tied to an underlying portfolio of defaultable reference assets and have payoffs that depend on the default times of these assets. The hedging of credit derivatives involves the calculation of the sensitivity of the contract value with respect to changes in the credit spreads of the underlying assets, or, more generally, with respect to parameters of the default-time distributions. We derive and analyze Monte Carlo estimators of these sensitivities. The payoff of a credit derivative is often discontinuous in the underlying default times, and this complicates the accurate estimation of sensitivities. Discontinuities introduced by changes in one default time can be smoothed by taking conditional expectations given all other default times. We use this to derive estimators and to give conditions under which they are unbiased. We also give conditions under which an alternative likelihood ratio method estimator is unbiased. We illustrate the application and verification of these conditions and estimators in the particular case of the multifactor Gaussian copula model, but the methods are more generally applicable.      

实物平台型的变电站培训仿真系统

变电站培训仿真系统是以真实变电站为模型设计的专门培训变电站运行值班人员的教学系统。变电站培训仿真系统实物平台方案在吉林油田八家予变电站培训仿真项目上得到了应用,这种实物平台结构简单、实时性好,有利于提高仿真的真实度,具有很好的应用前景。     

An assessment of the interruption level of doctors in outpatient appointment scheduling

Interruptions to the server in an outpatient clinic environment have received limited attention in the appointment scheduling literature. However, explicitly modeling interruptions on the part of the doctor may have an impact on the optimal appointment schedule and consequently, on patient waiting times. This is explored with a simulation optimization model that is based on data from time studies and interviews with medical professionals from multiple outpatient clinics. The results show a “plateau-dome” scheduling rule for practical implementation to be robust for low interruption rates and a traditional dome pattern for higher levels of interruptions. In addition, if clinic operations are such that doctors are able to adjust their behavior to complete all work during the session, then the schedule is invariant to changes in the interruption rate.     

Aspen plus软件在燃煤发电系统中的应用

介绍了Aspen plus软件相关功能,阐述了灵敏度分析和过程优化功能的特点.详细论述了该软件具有的单元操作模块在发电流程中的应用,为燃煤发电系统的研究提供参考.     

Axiomatic approach to approximate solutions in multiobjective optimization

An axiomatic approach is introduced in order to study the approximate solution map of a vector optimization problem in the image space. We investigate the possibility to formulate an appropriate notion of approximate solutions that is compatible with von Neumann–Morgenstern utility theory. An impossibility result is proved in the sense that, whenever all of the axioms are satisfied, either the set of the approximate solutions is a subset of the exact solutions of the problem, or it coincides with the whole admissible set. Moreover, the geometry of the approximate solution map is studied in some special cases.      

基于粒子群优化反向传播神经网络的铁路路基沉降量预测

铁路路基沉降规律复杂、沉降量难以预测,因此提出一种粒子群优化反向传播神经网络的路基沉降量预测模型。传统神经网络建模时存在收敛速度慢、易陷入局部极小值等不足。因此,通过粒子群算法修正网络的初始权/阈值,提高全局收敛性,建立基于粒子群优化的反向传播神经网络预测模型。通过对宝中线实测数据进行仿真实验,结果显示：经粒子群优化的神经网络可避免局部极小问题,加快网络收敛速度,提高了对铁路路基沉降量的预测精度。     

交通运输系统韧性研究综述

交通运输系统同国计民生、社会安定及可持续发展息息相关,且极易遭受自然及人为因素破坏,因此更需提高治理水平。通过对国际交通运输系统韧性研究相关文献的回顾及分类研究,阐述韧性的概念源起、韧性理论的视角转变,进而阐释不同学者对于综合城市交通系统韧性的概念探索。在此基础上,梳理总结交通运输系统韧性研究的定量评估方法,并以此为基础,从不同视角关注专家学者韧性提升措施研究。以期为相关研究者提供思路及借鉴。