Optimal investment with vintage capital: Equilibrium distributions

The paper concerns the study of equilibrium points, or steady states, of economic systems arising in modeling optimal investment with vintage capital, namely, systems where all key variables (capitals, investments, prices) are indexed not only by time but also by age. Capital accumulation is hence described as a partial differential equation (briefly, PDE), and equilibrium points are in fact equilibrium distributions in the variable of ages. A general method is developed to compute and study equilibrium points of a wide range of infinite dimensional, infinite horizon, optimal control problems. We apply the method to optimal investment with vintage capital, for a variety of data, deriving existence and uniqueness of equilibrium distribution, as well as analytic formulas for optimal controls and trajectories in the long run. The examples suggest that the same method can be applied to other economic problems displaying heterogeneity. This shows how effective the theoretical machinery of optimal control in infinite dimension is in computing explicitly equilibrium distributions. To this extent, the results of this work constitute a first crucial step towards a thorough understanding of the behavior of optimal paths in the long run.     

Comparison of dimension reduction methods for DEA under big data via Monte Carlo simulation

Data with large dimensions will bring various problems to the application of data envelopment analysis (DEA). In this study, we focus on a “big data” problem related to the considerably large dimensions of the input-output data. The four most widely used approaches to guide dimension reduction in DEA are compared via Monte Carlo simulation, including principal component analysis (PCA-DEA), which is based on the idea of aggregating input and output, efficiency contribution measurement (ECM), average efficiency measure (AEC), and regression-based detection (RB), which is based on the idea of variable selection. We compare the performance of these methods under different scenarios and a brand-new comparison benchmark for the simulation test. In addition, we discuss the effect of initial variable selection in RB for the first time. Based on the results, we offer guidelines that are more reliable on how to choose an appropriate method.     

The Ethical Dimensions of Decision Processes of Employees

The influence of stakeholders, organisational commitment, personal values, goals of the organisation and socio-demographic characteristics of individuals on the ethical dimension of behavioural intentions of employees in various organisations are investigated. The research results show that employees working for the public sector or in educational institutions take more ethical aspects into account than employees working in the "private" sector. The influence of stakeholders and organisational commitment do not significantly affect the ethical behaviour of employees, and only some personal values and goals of the organisation have a significant influence on ethical behaviour. The most significant explanatory factor of ethical decision making seems to be what may be called "stage in the career of the employee": "ethical" employees can be described as young, with a relatively low income, limited work experience and a low level of responsibility in the company.     

基于分形理论的广西城市体系空间结构研究

城市是人口和经济的聚集地,城市体系空间结构具有分形几何特征。将分形理论与中心地理论相结合,通过城市体系的关联维数模型计算出广西城市体系空间结构的分维值,发现广西城市体系的空间分布是具有分形特征,城市体系自组织演化在空间结构方面具有优化趋势,可以强化中心、极化南宁核心地位,重点扶持桂林、柳州、北海三个副中心建设,构建"一枢纽、二港口、三通道、四辐射"大通道体系和点轴面相结合发展的广西城市体系空间结构。     

基于时间维度的组织学习理论——组织从过去经历中学习的模型

从经历中学习是组织学习的重要方面。从科学、严谨的研究范式出发,结合东方传统的"阴阳"哲学思想,基于时间维度提出了包含学习主体、经历样本、成功失败经历集、学习主体特征、"知"和"行"等要素的组织从过去经历中学习的模型,并对相关问题进行了探究。具体包括:学习主体从经历中学习的认知特性;不同类型经历对应的不同学习方法,成功经历和失败经历对学习效果的差异性影响,经历集影响"知"和"行"的7种自动的和有意的学习方式;"知"与"行"相互转化及其触发机制;客观世界从时间和空间两个维度客观展开的观点等。该系统模型为未来研究提供了理论框架和实证检验方向。     

我国大众文化的双重维度辩证发展探析

建国以来，我国的文化发展可分为两个时期：改革开放之前主要发展文化事业，改革开放后，文化产业的越来越快速发展。当前，我国文化发展还存在很多的问题。一定要将文化事业与文化产业结合发展，两个维度和谐统一，促进文化健康发展。     

基于多维技术创新地图维法耦合的技术创新路径构建及实例分析

基于现有创新理论并结合当代技术发展特征,创建了多维技术创新地图,构建了基于多维技术创新地图维法耦合的技术创新路径。结合煤层气开采卸压消突创新实例,验证了该方法的可行性和有效性,即提高了技术创新路径构建的客观性,从技术创新本质层面指导技术创新活动的开展,有助于为企业开展技术创新活动提供决策支持。     

企业员工沉默行为研究述评及启示

当员工有能力改进当前企业绩效时,却对企业中存在的潜在问题保留了相关观点,这种现象被称为员工沉默。虽然员工沉默有助于减少管理信息泛滥,使得组织关系更为融洽。但同时其给企业和个人带来了很多负面影响,应引起广泛关注。     

基于时空维度的城市滨水区的开发导向

滨水区因其开阔的水面、开放的空间,成为当地居民和外地游客休闲游憩的首选场所;同时也因其良好的区位条件和土地资源,成为众多城市增长和城市更新的首要关注对象,由此产生不同导向的城市滨水开发方式。在回顾国内外大量相关文献的基础上,从时空维度梳理和归纳了城市滨水区开发模式的五种导向,即交通水道导向、住区品质导向、边缘新城导向、遗产飞地导向与复合开发导向,并重点分析了五种导向的功能内涵和开发空间特点。据此进一步提出城市滨水区开发星座模型,且将各个导向的开发模式空间特征、主导功能和典型形式做了比较性总结,并对城市滨水区的开发提出了具有针对性与操作性的建议。     

UASB反应器设计及启动实验

UASB反应器是当前发展最快的一种废水处理工艺。本文重点介绍了UASB反应器的设计原则和设计方法,以及UASB反应器各部分尺寸的计算和确定原则,并对反应器进行了常温启动实验。实验结果表明:用葡萄糖配水模拟生活污水,进水COD控制在500mg/L,反应器运行一个月,进水COD去除率达到71.2%。进水的pH控制在7.5-8.0可以保证反应器的正常稳定运行。