Adult ; Asian People / psychology* ; Attitude of Health Personnel / ethnology* ; Attitude to Death / ethnology* ; Brain Death* ; Comprehension ; Cross-Sectional Studies ; Cultural Characteristics ; Educational Status ; Employment / psychology ; Female ; Health Knowledge, Attitudes, Practice / ethnology* ; Humans ; Male ; Marital Status / ethnology ; Middle Aged ; Republic of Korea / epidemiology ; Surveys and Questionnaires ; Tissue and Organ Harvesting / psychology* ; Tissue and Organ Procurement* ; Young Adult