Computer system and method of determining model switch timing

A method of determining model switch timing comprising:

• in a computer system that diagnoses an abnormality of time series data from a machine learning model created based on learning data, when timing of switching of the machine learning model is determined,
• a model degradation detecting step of detecting degradation in the machine learning model;
• a learning curve estimation step of estimating a learning curve of the machine learning model to predict a number of errors per unit time using the learning curve;
• a model switch cost calculating step of calculating a number of errors per the unit time of a model in operation that is a machine learning model presently being used, a number of errors per the unit time of a switch candidate model that is a switch candidate of a model in operation, a first total cost when a machine learning model is switched at given first time based on error cost information that defines a cost per error, and a second total cost when a machine learning model is switched at given second time;
• and
• a model switch time predicting step of comparing the first total cost with the second total cost to calculate switch time of a machine learning model.