Modeling complex systems

Empirical observations suggest that linear dynamics are not an adequate representation of ecological systems and that a realistic representation would require adoption of complex nonlinear dynamical systems with characteristics encountered in complex adaptive systems (CAS). Adequate modeling should include and combine elements, such as strategic interactions among economic agents, nonconvexities induced by nonlinear feedbacks, separate spatial and temporal scales and modeling of spatiotemporal dynamics, and allowance of alternative time scales. Ignoring these characteristics might obscure very important features that we observe in reality, such as bifurcations and irreversibilities or hysteresis. As a consequence, the design of policies that do not take CAS characteristics into account might lead to erroneous results and undesirable states of managed economic–ecological systems.     

本地能力视角下战略性新兴产业政策扩散研究——以中国内地31省份新材料政策为例

识别产业政策扩散背后驱动因素能为政府科学制定政策和正确选择产业提供理论指导，本地能力对战略性新兴产业政策扩散具有重要影响。以2005-2018年新材料政策在我国内地31个省市区的扩散过程为例，分析省级战略性新兴产业政策扩散机制。研究发现：本地能力影响省级战略性新兴产业政策扩散，其中资源禀赋、产业实力和知识技能对政策扩散有正向影响，制度环境对政策扩散有负向影响；中央政府应避免强制推行产业政策导致的资源浪费，地方政府应因地制宜地发展战略性新兴产业并不断增强本地能力建设。     

体育经济的集聚效应与扩散效应分析

体育经济的集聚与扩散效应是体育产业发展中一对相互推动的基本作用力,集聚效应表现为不同体育产业间的互补效应、竞争效应与稳定效应;扩散效应是体育经济发展到一定程度,所形成的周边式扩散、跳跃式扩散、等级式扩散以追求范围经济的过程。体育经济特殊的集聚与扩散效应的发挥可以通过制度、品牌、产业、体育人才等要素实现协同发展。     

基于扩散指数模型的房地产市场景气循环研究——以北京市为例

基于扩散指数模型构建房地产市场景气循环指标体系，采用北京市住宅市场与经济基本面的历史数据，计算不同时期北京市房地产市场的扩散指数，绘制北京市房地产市场的景气循环曲线，并根据景气循环曲线与历史数据对北京市未来房地产市场的景气情况进行预测。最后，提出在上述市场预测情况下的市场调控策略。     

The impact of adoption timing on new service usage and early disadoption

Post-adoption usage can be a crucial element in obtaining substantial revenues from new service introduction, especially when adopters display low usage levels or decide to disadopt the service altogether. Here, the authors specifically examine the effects of adoption timing on post-adoption usage and disadoption. Using a longitudinal, individual-level usage data set of 6296 adopters of a new telecom service, they show that the earliest adopters have lower initial usage levels than do later adopters. However, early adopters show increasing usage after adoption, whereas late adopters tend to decrease their usage over time. Also, disadoption rates are higher among later adopters.     

Should environmental R&D be prioritized?

An innovator may not be able to capture the full social benefit of her innovation and, therefore, governments support private R&D through various measures. We compare a market good innovation—to develop a more efficient technology to produce a standard market good—with an environmental innovation—to develop a more efficient abatement technology—that has the same potential to increase the social surplus. In the first-best outcome, which can be achieved by offering an R&D subsidy and a diffusion subsidy, the R&D subsidy should be greatest for an environmental innovation, whereas the diffusion subsidy should be greatest for a market good innovation. The ranking of the two types of subsidies reflects that the appropriability problem is greater for an environmental innovation than for a market good innovation.     

Identifying the impact of geographical proximity on spillover effect of FDI: The evidence from Indian local firms’ performance gains

This paper investigates the role of geographical proximity on FDI spillovers from foreign to Indian local firms. We use data set of the manufacturing firms between 1988 and 2018 in India, estimating the productivity based on Cobb–Douglas production function. For measuring geographical proximity, the coordinates of each firm, represented to as ‘latitude and longitude’, provided by Google maps geocoding API is used. To conduct spatial analysis, we adopted the revised ‘SINM’ (Spatial Industrial Network Model)’ with GMM estimator, and used firm based point spatial unit. The analysis, in particular, reveals that within 30 km–70 km distance the presence of FDI creates significant positive backward and negative horizontal spillovers, but gradually decaying as threshold increases. Meanwhile, the negative horizontal spillovers to Indian local firms located within industrial clusters turned to positive, and the positive backward spillovers more magnifies compared to non-clustered firms. Based on these findings, we suggested the several policy implications regarding the development of industrial cluster, FDI promotion policy, and location decision for foreign investors.     

互联网与业务流程融合的创新扩散及关键因素研究

依据创新扩散理论与流程观，提出一种企业互联网融合（互联网与业务流程融合）测度模型，包括信息化管理影响因素和相关假设，并将互联网与价值链上业务流程融合规模作为互联网融合的度量标准。基于196家传统企业调查数据，采用Logistic模型和结构方程建模对样本数据进行对比分析，验证所提出的模型及假设，揭示企业实施互联网技术支持业务活动的状况，鉴别企业之间互联网融合差异的关键解释因素，同时提出一种研究企业实施互联网技术支持业务活动的新途径。     

考虑影响不对称性的创新扩散与网络结构协同演化建模：基于信息熵与累积优势的仿真研究

创新扩散发生于社会系统中并通常与社会系统存在交互作用。网络是体现社会系统的重要手段，但已有研究中的扩散网络多为无向网络且具有静态或外生动态性质，上述处理方式忽视或无法体现扩散与以网络形式出现的社会系统的协同演化以及个体间的不对称影响。基于有向网络，提出能够体现创新扩散与网络协同演化的描述性框架，从信息搜寻与降低认知失调视角出发，基于信息熵与累积优势机制，在个体层面构造网络演化与创新采纳数学模型。在RepastSimphony2.7开发平台下，利用基于Java的智能体建模方法展开系统仿真实验。基于实验数据的描述性结果揭示，动态网络与静态网络下的创新扩散存在显著不同，网络结构演化将强化节点出度的不均衡状况，更优的扩散结果往往与更不均衡的节点出度分布同时出现，其它因素包括大众传播与人际传播等也会影响扩散与网络的协同演化；交互作用存在于控制变量间。推断性结果确认了控制变量影响与交互作用的普遍存在。