【摘要】 运用Granovet t er的集体行动理论和经典阈值模型,在研究股票市场中投资者行动特征基础上,增设复杂网络和异步时间构建拓展阈值模型,通过计算机仿真,研究股市风险在复杂网络下的动态扩散。研究发现:(1)风险阈值特征值激活时,不管网络结构如何,均发生股市灾害。(2)投资者集体规模的扩大,推高了股灾激活阈值,有助于降低股灾发生的风险。(3)风险波动呈现区间效应,当投资偏好异质性高度趋同或趋异时,在复杂网络下,风险扩散可能性更小,速度更慢,原因是复杂网络容易促成趋势的更高度一致或更高度离散,从而降低整体系统风险。但正常证券市场中,投资偏好异质性处于中间状态,复杂网络的信息传播促使风险扩散速度更快,风险更高,范围更广。因此,借助"互联网熟人社会"复杂网络力量,促成更高度一致或高度离散的决策行为,有助于降低金融系统整体风险。这对投资者和金融系统监管都具有一定的启示作用。更多还原

【Abstract】 By employing the collective behavior theory and the classical threshold model, this paper firstly studies the characteristics of investors’ behaviors in the stock markets, then based on that,it adds two elements of the complex network and the asynchronous time to establish an extended threshold model. Through computer simulation, it studies the dynamical diffusion of stock market risks in the complex networks. The findings show that:(1) firstly, when the characteristics of risk threshold value are activated, no matter what kind of the network structure is, there will be the stock market disasters; secondly, the expansion of the investor scale can increase the threshold value to activate stock market disasters, thus it can reduce the risk of stock market crash; thirdly, the risk volatility presents an interval effect, when the investment preference heterogeneity is highly convergent or divergent, the possibility of risk diffusion is less and the speed is slower in the complex network, the reason is that the complex network is easy to promote the trend more consistent or discrete, so as to reduce the risk of the whole system. However, in the normal securities markets, the investment preference heterogeneity is located at the intermediate state, the information dissemination of the complex network will drive the speed of risk diffusion to be faster, and the risk will be stronger and wider.Therefore, to take advantage of the power of "Internet Acquaintance Society" to promote the decision-making behaviors for still higher consistentance or higher dissociation can help to reduce overall risk of the financial system. This has certain implications for investors and financial system regulation.更多还原