Employment effects of business dynamics: Mice, Gazelles and Elephants

Much of the theoretical work on industry dynamics focuses on the role of ‘noisy’ selection and incomplete information on firm entry and survival. We extend this research by looking at the impact of firm heterogeneity on employment effects for 320 U.S. Metropolitan Statistical Areas (MSA). We find that only start-ups with greater than 20 and less than 500 employees have persistent employment effects over time and only in large diversified metropolitan regions. Therefore, both the type of entry (Gazelles) and the characteristics of the region are important for employment growth.

Multiple Levels of Corporate Sustainability

According to Dr. Clare Graves, mankind has developed eight core value systems,1 as responses to prevailing circumstances. Given different contexts and value systems, a one-solution-fits-all concept of corporate sustainability is not reasonable. Therefore, this paper presents various definitions and forms of sustainability, each linked to specific (societal) circumstances and related value systems. A sustainability matrix– an essential element of the overall European Corporate Sustainability Framework – is described showing six types of organizations at different developmental stages, with different forms of corporate sustainability, each supported by specific institutional arrangements.     

从文献计量分析看1981—2011年全球系统动力学研究

系统动力学作为一个研究复杂反馈系统的研究领域,在20世纪80年代以后得到了较为广泛的传播和较快发展。以美国科学引文索引数据库扩展版(SCI-Expanded)和社会科学引文索引数据库(SSCI)收录发表于1981—2011年间的976篇系统动力学论文为研究对象,对这些论文的产出规模、地域分布、学科分布、知识基础等方面进行了计量分析。结果显示,30余年来,全球系统动力学成果产出逐渐丰富,理论研究与应用研究得到积极推进,与众多学科联系紧密,各国科研投入力量在不断加强,同时也反映出,美国系统动力学研究在全球一枝独秀。     

信息物理融合系统软件可信性演化动力学建模

信息物理融合系统(CPS)软件可信性建模是CPS可信软件开发过程中至关重要的一环,现有的形式化方法、软件验证技术并不适合对CPS软件可信性动态演化进行描述和分析。在深入分析CPS可信软件动态演化过程的基础上,结合非线性动力学的基本理论和方法,研究CPS软件可信性演化的动力学机制,对CPS软件在内外双重因素影响下的可信性演化过程进行建模,并分析其可信性演化规律,为CPS软件可信性研究提供了一种新手段。通过对一个工业控制领域中CPS软件的建模与分析,验证了该方法的可行性。     

创新投入对区域科技创新能力的影响研究——以江苏省为例

采用系统动力学方法,围绕政府、高校与企业3个主体构建系统动力学模型,探究不同因素对于江苏省科技创新能力的影响程度。结果显示：政府长期的科技支出与教育支出均能够促进江苏省科技创新水平的提升,但短期内加大教育支出并不能立竿见影;适当增加高校在校生人数有利于促进区域内发明专利的产出,提升江苏省科技创新水平;企业可适当加大对企业内部的R&D经费投入,促进企业创新性成果的产出,进而提升区域创新能力。     

Fiscal Stimulus in Times of High Debt: Reconsidering Multipliers and Twin Deficits

We investigate the impact of fiscal stimuli at different levels of the government debt‐to‐GDP ratio for a sample of 17 European countries from 1970 to 2010. This is implemented in an interacted panel VAR framework in which all coefficient parameters are allowed to change continuously with the debt‐to‐GDP ratio. We find that responses to government spending shocks exhibit strong nonlinear behavior. While the overall cumulative effect of a spending shock on real GDP is positive and significant at moderate debt‐to‐GDP ratios, this effect turns negative as the ratio increases. The total cumulative effect on the trade balance as a share of GDP is negative at first but switches sign at higher levels of debt. Consequently, depending on the degree of public indebtedness, our results accommodate long‐run fiscal multipliers that are greater and smaller than one or even negative as well as twin deficit and twin divergence behavior within one sample and time period. From a policy perspective, these results lend additional support to increased prudence at high public debt ratios because the effectiveness of fiscal stimuli to boost economic activity or resolve external imbalances may not be guaranteed.     

Investment Dynamics with Information Costs

Investment in physical capital at the microlevel is infrequent and large, or lumpy. The most common explanation for this is that firms face nonconvex physical adjustment costs. The model developed in this paper shows that information costs make investment lumpy at the microlevel, even in the absence of nonconvex adjustment costs. When collecting and processing information are costly, the firm optimally chooses to do it sporadically and to be inactive most of the time. This behavior results in infrequent and possibly large capital adjustments. The model fits plant‐level investment rate moments well, and it also matches some higher order moments of aggregate investment rates.     

系统动力学视角下城市群绿色低碳路径研究

碳达峰和碳中和的提出对城市群发展提出新的要求,城市群高速发展与环境问题间的矛盾日益加剧,绿色低碳发展路径亟待研究.以京津冀城市群为研究对象,在梳理城市群发展影响因素的基础上,分析城市群循环系统构成中要素间的关联关系,并通过量化模型,搭建基于系统动力学的城市群绿色低碳发展系统;重点从经济、能源、环境和城市聚合4个角度构建仿真系统,建立要素间量化函数,设定基本场景,以2010—2019年数据为基础,对系统进行仿真运行.算例结果表明,构建的仿真系统通过了检验,拟合程度较好;通过设计不同场景,验证相关参数变化时对系统运行的影响程度,发现综合场景对未来系统运行效益最佳,兼顾了经济发展与碳减排问题,能够促进城市向群绿色低碳发展.     

Smallholder land ownership in Kenya: distribution between households and through time

This study uses panel data to demonstrate two dimensions of land ownership: the distribution between households at a given time and changes within a household over time. We note that recognizing the latter dimension is only possible when analyzing rare long‐term panel data. We estimate a model for land ownership using a version of the correlated random effects estimator to uniquely identify the determinants of both dimensions amongst Kenyan smallholders. We find life cycle effects are a key determinant of both distributions, and identify important ways in which initial conditions such as inheritance and off‐farm income relate to the dynamics of ownership. We find that population density is a key determinant of differences between households, but also that a given household's land ownership is not affected in the short term as population density increases around them. Controlling for population density, households own more land when they are closer to road networks where the economic value of land is higher. We find important vulnerabilities for the land security of widows, but this vulnerability is geographically heterogeneous.     

基于系统动力学的农业订单融资研究——以奶牛养殖订单融资为例

近年来,随着供应链金融在全球的迅猛发展,中国农业订单融资应运而生,但对其研究尚待深入。从定量研究的角度,运用系统动力学方法,以奶牛养殖订单融资为例,建立奶牛养殖订单融资系统动力学模型,探讨农业订单融资运作的动态特性及其对供应链绩效的影响并通过模拟仿真分析农业订单融资相关参数的设定。最后,提出促进中国农业订单融资发展的具体建议。