I Vai mot tap yeu cau truyen thong, muc tieu la thiSt lap tat ca cac lightpath cho cac yeu cau nay sao
a) Biiu diin cua mot phan tir
^ ap dung dugc thuat toan PSO cho bai toan thi
'iec dSu tien chiing ta phai tim dugc each bieu dien
Ilia cac phan tu sao cho moi phin tú la mpt giai >hap cua bai toan. Thong thuong, co ba phuong >hap ma hoa: ma hoa s6 thue, ma hoa so nguyen, na hoa bit nhi phin. Trong bao cao nay, phuong ihap dugc su dung la phuong phap ma hoa so thuc. f6i phin tir la mot vecto TV chilu (Â la so cac yeu au kit noi) ma moi thanh phan la mot so thyc 'cmg img voi cap nguon - dich ciia mot yeu caụ
Cu the, ky hieu cac yeu ciu ket noi la {{s\,d]), ...,
{Sn,dn)} trong do s, va d, la nut mang, mpt phan Xuj
trong thuat toan PSO la {c/\, ..., d„] thi d, se tuong irng voi yeu cau ket noi {s„d,) va nhan mpt gia tri
thuc dugc sinh ngau nhien. Gia sir so buoc song doi
ta tren moi lien ket vat ly la W. Khi do qua trinh xiy
dung mot topo ao (thiet lip cac lightpath) tir mot phan tiry se dugc thuc hien nhu sau:
{Thuat todn gidi md doi v&i mat phan tu}
(1) Xiy dung do thj G la do thj phan tang gom
cac ting Gy, G2, .., Giv ma moi ting la mpt
ban sao ciia topo vat lỵ Neu co mpt thiet bi chuyen doi buoc song dat 0 niit v trong topo vat ly, khi do se co mpt canh noi v' o ting /
voi v' o t i n g y voi (/ ^j va i,J =1,2,... W). Khi do, moi cap nguon dich (s, d) tren topo
vat ly se tuong irng voi:
mpt bp cac cap {s^, (f) (p = 1, 2, .., W)
cho truong hgp mang khong c6 thiet bj
chuyen doi buoc song; trong do / , (f la ban sao ciia cac dinh s vd d tai tang thir
P-
mpt bp cac cap {s^, d') (p,q ^ /, 2, ..,