7161
Rational design of experiment is employed to optimize the contour parameters to improve surface finish of inclined surfaces .
 concept or principle: design of experiment; engineering feature: contour; engineering feature: surface finish; concept or principle: surfaces
Given options, please tell me the categories of all the listed entity words.Output format is "type1: word1; type2: word2". 
Option: manufacturing standard, machanical property, manufacturing process, material, engineering feature, process parameter, machine or equipment, application, process characterization, enabling technology, biomedical, concept or principle 
Text: {0} 
 Entities: design of experiment, contour, surface finish, surfaces 
Answer:
 concept or principle: design of experiment; engineering feature: contour; engineering feature: surface finish; concept or principle: surfaces