1. An expert system, comprising: a data storage device, in which is stored a knowledgebase having a database structure that includes: a plurality of models, each defining one of a device and a process, each model including a plurality of attributes including a variable attribute, the attributes corresponding to attributes of one of the device and the process defined by the model; a plurality of objectives, each objective including an objective rule for evaluating a characteristic of at least one of the models; a plurality of strategies, each strategy including a strategic rule for modifying the variable attribute of at least one of the models; and a sub-knowledgebase including an identification of at least one of the models, an identification of at least one of the objectives, and an identification of at least one of the strategies; and a processor coupled to the data storage device, the processor executing instructions which, cause the processor to: evaluate a selected model identified in the sub-knowledgebase in accordance with a selected objective identified in the sub-knowledgebase, the variable attribute of the model being set in accordance with a selected strategy identified in the sub-knowledgebase to determine a characteristic value associated with the selected model and the variable attribute setting; determine, using the objective rule, whether the characteristic value is an improvement over a previous characteristic value; and store a result in the storage device so as to be accessible to a user when the characteristic value is an improvement over the previous characteristic value, the result including an identification of the selected model and the variable attribute setting used to determine the improved characteristic value for one of the device and the process defined by the model.