The safety assessment system based on virtual networked environment for evaluation on the hazards from human errors during decommissioning of nuclear facilities /Kwan Seong Jeong a,n , Byung Seon Choi a , Jei Kwon Moon a , Dong Jun Hyun a , Jong Hwan Lee a , Ik June Kim a , Shin Young Kang a , Jong Won Choi a , Sang Myeon Ahn b , Jung Jun Lee b , Byung Sik Lee - Jeong,Kwan Seong