Frequent-purchased Models and Maximum Likelihood Estimationfor Its Parameters;

Taking Amazon as an example, this paper has analyzed the customer services offered by the online bookstores and service standards of purchasing decision-making model in each phase, so as to help the domestic online bookstores to formu- late a better customer service strategy.

The theory is mainly about the application of Bass model and the repurchasing model.

Based on the analysis of the models of a single university library to purchase digital resources (mainly Chinese digital resources) through negotiations, this paper analyzes the factors and cost problems the library should take into account in selecting purchasing models.

On the basis of reviewing the reason for the insufficient consumption in China,the paper starts from the dynamic balance of urbanrural purchasing to establish the collocation model of urbanrural purchasing power under the maximum consumption condition of urbanrural residents, and proposes some operative conclusions by applying the model.