1. Department of Internal Medicine, College of Medicine Yeungnam University, Yeungnam University Medical Center Daegu South Korea
2. Department of Thoracic and Cardiovascular Surgery, College of Medicine Yeungnam University, Yeungnam University Medical Center Daegu South Korea
3. Division of Pulmonology and Allergy, Department of Internal Medicine, College of Medicine Yeungnam University and Regional Center for Respiratory Diseases, Yeungnam University Medical Center Daegu South Korea