 In 1938 , <unk> Pibulsonggram , as President of Chulalongkorn University , assigned ML Pin the duty of overseeing the establishment of Chulalongkorn 's University Preparatory School according to the National Education Plan of BE <unk> ( 1936 CE ) . Although given a tight time frame of only three months , the new school was created on the location of <unk> School , and gradually absorbed the older school , the entire staff merging within a few years . ML Pin became the first director of the school , the country 's first coeducational school , now known as <unk> Udom <unk> School . It is widely regarded as one of the best schools in the country . During his term as director , which lasted until 1944 , he developed and implemented a fixed class schedule system , along with a mechanical timetable used to assign teaching periods , which is still in use today . 
