Hosseiny Ali, Bahrami Mohammad, Palestrini Antonio, Gallegati Mauro
Department of Physics, Shahid Beheshti University, G.C., Evin, Tehran 19839, Iran.
Department of Economics, Università Politecnica delle Marche, Ancona, Italy.
PLoS One. 2016 Oct 5;11(10):e0160363. doi: 10.1371/journal.pone.0160363. eCollection 2016.
It is well known that a network structure plays an important role in addressing a collective behavior. In this paper we study a network of firms and corporations for addressing metastable features in an Ising based model. In our model we observe that if in a recession the government imposes a demand shock to stimulate the network, metastable features shape its response. Actually we find that there exists a minimum bound where any demand shock with a size below it is unable to trigger the market out of recession. We then investigate the impact of network characteristics on this minimum bound. We surprisingly observe that in a Watts-Strogatz network, although the minimum bound depends on the average of the degrees, when translated into the language of economics, such a bound is independent of the average degrees. This bound is about 0.44ΔGDP, where ΔGDP is the gap of GDP between recession and expansion. We examine our suggestions for the cases of the United States and the European Union in the recent recession, and compare them with the imposed stimulations. While the stimulation in the US has been above our threshold, in the EU it has been far below our threshold. Beside providing a minimum bound for a successful stimulation, our study on the metastable features suggests that in the time of crisis there is a "golden time passage" in which the minimum bound for successful stimulation can be much lower. Hence, our study strongly suggests stimulations to arise within this time passage.
众所周知,网络结构在解决集体行为方面起着重要作用。在本文中,我们研究了一个企业网络,以解决基于伊辛模型的亚稳态特征。在我们的模型中,我们观察到,如果在衰退期间政府施加需求冲击以刺激网络,亚稳态特征会塑造其反应。实际上,我们发现存在一个最小界限,任何低于该界限的需求冲击都无法使市场摆脱衰退。然后,我们研究网络特征对这个最小界限的影响。我们惊讶地观察到,在瓦茨 - 斯托加茨网络中,尽管最小界限取决于度的平均值,但用经济学语言来说,这样的界限与平均度无关。这个界限约为0.44ΔGDP,其中ΔGDP是衰退和扩张之间的GDP差距。我们研究了美国和欧盟在最近衰退期间的情况,并将我们的建议与实际实施的刺激措施进行了比较。虽然美国的刺激措施高于我们的阈值,但欧盟的刺激措施远低于我们的阈值。除了为成功的刺激提供一个最小界限外,我们对亚稳态特征的研究表明,在危机时期存在一个“黄金时间段”,在此期间成功刺激的最小界限可能会低得多。因此,我们的研究强烈建议在这个时间段内进行刺激。