管理领域中若干扩散性问题的元胞自动机模型

元胞自动机通过模拟个体之间的相互作用得到宏观结果,作为一种微观模型已经越来越广泛地应用于管理领域的研究。介绍了元胞自动机模型的机理,并分别针对管理领域中文化舆论传播、传染病传播以及创新扩散建立了元胞自动机模型进行研究。     

“粮食—生态”双安全约束下建设用地供需多情景模拟 ——以江苏省南京市为例

研究目的：以江苏省南京市为例,基于“反规划”理论,从“粮食—生态”双安全约束视角开展2030年和2035年建设用地供需多情景模拟,据此制定不同情景下建设用地差别化管控策略。研究方法：运用粮食需求预测法和景观生态安全格局构建法,反向测算研究区建设用地供给极限;并采用多元回归模型,结合建设用地扩张驱动因素,预测建设用地需求。研究结果：（1）“经济优先”、“生态涵养”和“均衡发展”三种情景下,2030年研究区耕地需求量分别为153 854.58 hm2、179 497.01 hm2、205 139.44 hm2,2035年达到157 157.71 hm2、183 350.67 hm2、209 543.62 hm2;景观生态安全格局构建结果显示,南京市低、中、高安全水平生态用地规模分别为153 741.28 hm2、257 684.61 hm2和292 859.35 hm2;三种情景下,2030年研究区建设用地需求量分别为200 121.21 hm2、194 060.53 hm2、195 683.63 hm2,2035年达到206 523.92 hm2、196 523.96 hm2、197 983.55 hm2;（2）相较于其他两种情景,均衡发展情景下目标年建设用地供需差整体较小,分别为785.40 hm2和-5 918.70 hm2,2030年建设用地供需基本平衡,到2035年存在一定程度缺口,该情景在满足经济发展对建设用地合理需求的同时,也能兼顾“粮食—生态”双安全的基本要求。研究结论：不同情景下建设用地供需状况差异明显表明需要制定差别化的管控策略,以均衡发展情景为目标,有利于协调区域经济发展、粮食安全和生态保护的多目标土地利用供需矛盾。     

盾构下穿河道地层沉降分析与支护力优化确定方法——以济南地铁4号线下穿刘公河为例

随着我国地铁的大力建设,施工中难免会面临下穿建筑物、桩基、管线、河流等情况的出现,因此对盾构施工的参数要求越来越高,施工难度逐渐增加。以济南轨道交通4号线邢村站至唐冶南站区间盾构施工为工程背景,利用ABAQUS有限元软件构建三维数值计算模型,对下穿河道高差过程中的不同开挖面支护力设定以及沉降位移变化进行研究。研究结果表明：全覆土理论下计算所得开挖面支护力对地表及河道的沉降控制效果最好;在不同支护力下,地层水平位移最大值均出现在隧道开挖面附近;隧道中心线上方的地层分层沉降量随着埋深的增加而增大。研究结论在盾构下穿高差地层的工程实际中具有指导意义。     

基于Multisim的负反馈放大电路仿真分析

为了提高教学效果,在教学过程中引入仿真教学方式。结果表明,利用仿真软件进行演示,能够形象的体现负反馈放大电路的典型特性,加强了学生对复杂电路的理解。     

百年中国劳动关系演化的 基本路径及走势*

本文基于马克思“历史的与逻辑的相统一”的方法论，系统勾勒了中国近百年来劳动关系历史演化的基本路径和走势：劳资两利、劳工异化与资本回归是百年中国劳动关系演化的基本线索；晋徽商帮、民国商会与国企民企折射百年中国雇主组织演变的历史轨迹；顶身股、包身工、固定工与农民工反映百年中国劳动者身份地位演化走势；立法规制、行政包办与宏观调控透视百年中国劳动关系管理的政府角色演变。鉴于中国历史传统、文化特色及转型现实，市场化、契约化与法治化应成为未来中国劳动关系发展的基本取向和战略选择。     

新城金矿开采顺序数值模拟分析

本次模拟研究区域主要集中在-580m中段,新城金矿Ⅴ#采用上向分层尾砂(胶结)充填采矿法,中段高50m,一个中段含5个分段,一个分段分3个分层。     

The effects of wind generation capacity on electricity prices and generation costs: a Monte Carlo analysis

We use Monte Carlo analysis to examine the potential of increased renewable generation to provide a hedge against variability in energy prices and costs. Fuel costs, electricity demand and wind generation are allowed to vary and a unit commitment and economic dispatch algorithm is employed to produce cost-minimizing generation schedules under different levels of installed wind capacity. Increased wind capacity reduces the mean and the variance of production costs but only the variance of electricity prices. Wind generators see their market revenues increase while consumer payments and fossil generator profits do not considerably vary as wind capacity increases. Risk aversion is captured by considering the conditional value-at-risk for both consumers and producers. The optimal level of wind generation increases as risk aversion increases due to the potential of wind to act as a hedge against very high electricity prices in high fuel price scenarios.     

基于供应链中需求信息共享的系统动力学研究

本文以汽车制造业中的零件配送为研究对象,针对供应链中的牛鞭效应,利用系统动力学的方法建模和仿真。研究表明,时间和市场需求信息对供应链的运作有显著影响。在单链和多链模型中,通过对有无需求信息共享、如何共享需求信息进行研究和对比,结果表明,信息的失真会加大供应链中的牛鞭效应,而只共享市场需求信息则有利于供应链的运作。     

The energy implications of city size and density

This paper develops a new open-city urban simulation model capable of showing the urban form and energy consumption effects of variation in city size. The model is able to consider city size differences caused by wage and amenity differentials, both with and without housing and land use regulation. The surprising conclusion is that per-capita energy use is relatively invariant to city size when growth is driven by wages but falls modestly with growth induced by rising amenity. Common land use policies, specifically density limits and greenbelts, can positively or negatively affect both city welfare and energy use.     

Methodological Expectations for Studies Using Computer Simulation

Simulation is often used in papers and studies across diverse fields like logistics, supply chains, health care, manufacturing, and defense. But simulations must be properly done, including input and model building, designing/analyzing the simulations, and model verification/validation. Unfortunately, simulation studies are not always done well, even though great effort could have gone into the model building and coding. This paper specifies, in brief outline, what authors and researchers need to do, when using simulation as a main tool, to build a convincing case for their findings and conclusions. Considerations on the input side of the model are enumerated, including specification of input distributions and processes; nonstationarity; random‐number generation; and generating realizations of random variables and random processes. On the output side are issues of statistical analysis of simulation output; comparison, selection, and ranking of simulated scenarios; variance reduction; and optimum seeking. Involving matters on both the input and output sides are the essential activities of verification and validation. The intent is to establish expectations on what acceptable papers need to do if using simulation, and to serve as a guideline to applied simulation studies. Such papers and studies will then be more valid, more precise, more useful, and ultimately more convincing.