We develop a new framework for modeling innovation networks which evolve over time. The nodes in the network represent firms, whereas the directed links represent unilateral interactions between the firms. Both nodes and links evolve according to their own dynamics and on different time scales. The model assumes that firms produce knowledge based on the knowledge exchange with other firms, which involves both costs and benefits for the participating firms. In order to increase their knowledge production, firms follow different strategies to create and/or to delete links with other firms. Dependent on the information firms take into account for their decision, we find the emergence of different network structures. We analyze the conditions for the existence of these structures within a mathematical approach and underpin our findings by extensive computer simulations which show the evolution of the networks and their equilibrium state. In the discussion of the results, particular attention is given to the emergence of direct and indirect reciprocity in knowledge exchange, which refers to the emergence of cycles in the network structure. In order to motivate our modeling framework, in the first part of the chapter we give a broad overview of existing literature from economics and physics. This shows that our framework bridges and extends two different lines of research, namely the study of equilibrium networks with simple topologies and the dynamic approach of hypercycle models.
Analysis of a voter model with an evolving number of opinion states
Advanced-Basic-Convergence Research Institute, Chungbuk National University（忠北国立大学先进基础融合研究院）；Department of Physics, Chungbuk National University（忠北国立大学物理系）；University of Florida（佛罗里达大学）
Is Europe Evolving Toward an Integrated Research Area?
一体化的欧洲研究区（ERA）是更具竞争力和开放的欧洲研发体系的关键组成部分。然而，欧盟特定的一体化政策，旨在克服与国家边界相关的创新障碍的影响还没有得到很好的理解。在这里，我们分析了1986-2010年25年间提交给欧洲专利局（EPO）的2.4 x 10^6项专利申请，以及ISI Web of Science的2.6 x 10^5项记录样本，以定量衡量边界在国际研发合作和流动中的作用。根据这些数据，我们为分析的每一年构建了五个不同的网络：（i）专利共同发明人网络，（ii）出版物共同作者网络，（iii）共同申请人专利网络，（iv）专利引用网络和（v）专利流动网络。我们使用网络科学和计量经济学的方法进行跨时间的比较分析，并在欧盟和非欧盟国家之间，以确定欧盟一体化政策产生的“待遇效应”。使用非欧盟国家作为对照组，我们提供的定量证据表明，尽管几十年来努力建立一个欧洲研究区，在专利和出版的全球趋势上几乎没有整合。这一分析提供了具体的证据，表明欧洲仍然是一个国家创新体系的集合体。
