Albert-László Barabási与Réka Albert在1999年的论文中提出了一个模型来解释复杂网络的无标度特性，称为BA模型。这个模型基于两个假设：

增长模式：不少现实网络是不断扩大不断增长而来的，例如互联网中新网页的诞生，人际网络中新朋友的加入，新的论文的发表，航空网络中新机场的建造等等。

优先连接模式：新的节点在加入时会倾向于与有更多连接的节点相连，例如新网页一般会有到知名的网络站点的连接，新加入社群的人会想与社群中的知名人士结识，新的论文倾向于引用已被广泛引用的著名文献，新机场会优先考虑建立与大机场之间的航线等等。

-Albert-László Barabási with Réka Albert in the 1999 paper proposed a model to explain the complex networks of scale-free property, known as the BA model. This model is based on two assumptions:

Growth pattern: a lot of real network is expanding growing from, for example, the birth of the Internet BEIJING, page, new friends to join the network of people, a new paper published aviation network in the new airport construction and so on.

Priority connection mode: a new node upon accession will tend to connect to the node connected to, for example, a new page will generally have a connection to the well-known networking sites, and the new Community will want with the community s well-known get to know the new paper preference is to use well-known literature has been widely cited, the new airport will give priority to create and airport routes.