1968
Hence , a compromise should be made to sample the solution space when the theoretical global optimal could not be located .
 material: be; concept or principle: sample; concept or principle: solution; concept or principle: theoretical; material: be
Please list all entity words in the text that fit the category.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} 
Answer:
 material: be; concept or principle: sample; concept or principle: solution; concept or principle: theoretical; material: be