2015
Currently , many optimization studies for lattice structures are only limited to density , represented by strut diameter , and very little work focuses on parameter optimization and computation benchmarking for large lattice structure design cases .
 concept or principle: optimization; engineering feature: lattice structures; machanical property: density; process parameter: strut diameter; concept or principle: parameter; concept or principle: optimization; concept or principle: computation; engineering feature: lattice structure design
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:
 concept or principle: optimization; engineering feature: lattice structures; machanical property: density; process parameter: strut diameter; concept or principle: parameter; concept or principle: optimization; concept or principle: computation; engineering feature: lattice structure design