关键词：传感器；集聚经济；集群硅谷；多元化
摘 要：The debate in the empirical literature and economic regional policy has been largely about stimulating fruitful environments. The success of clusters like Silicon Valley and diversified cities such as New York City stimulated many scientific and policy projects on this subject and incited a massive literature on agglomeration economies. Many papers focus on the question whether specialised or diversified cities are the most fruitful environments. Duranton and Puga (2001) were the first to point out that both types are important in a system of cities. The question remains however how to induce such a beneficial environment and whether the advantages of proximity are similar in both city types.