... chi tiet hon theo V! tri, lnrong va dc$ dai, Ben canh ky thu~t trich chon bc$dau hieu co gia tri phan bi~t M xu· ly bai toan nhan dang theo huong thong ke, each tiep c~n vec to' hoa theo ki~u duy~t ... vao hang dq-i va tinh d9 cong b~ng phirong phap "xap xi theo ba doan" [3], Dirng quay lai c~p nen-vung xuat phat Theo phirong phap xap xi theo ba dean, de' xay dung tieu chuin ph at hi~n die'm ... nen-vung phu hop 'an ky tiep theo Lira chon die'm bien n vi~c xU- Ngu g~p Iai die'm xuat phat thl dirng, ngu khOng quay lai Kgt thuc ie'm P co De' xac dinh c~p nen vung Wfp theo, doi hoi phai hra...