5091
A simple proportional integral derivative ( PID ) controller , combined with feed-forward compensation was used to build a closed-loop control system for achieving a uniform molten pool size .
 manufacturing process: simple; machine or equipment: controller; process parameter: build; machine or equipment: closed-loop control; concept or principle: molten pool
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: simple, controller, build, closed-loop control, molten pool 
Answer:
 manufacturing process: simple; machine or equipment: controller; process parameter: build; machine or equipment: closed-loop control; concept or principle: molten pool