A new kind of products to be set up using control components is one of new research directions in theory of codes recently. Type of codes like that zigzag codes or T-codes been studied by different scientists. In this paper, a new product of words is proposed and named as the spring product. On the basics of the propose, a new type of codes, ., spring codes is considered and certain basic properties are established which permits to build an algorithm checking wherther a given regular language is spring code or not | T{tp chf Tin hoc va f)i'eu khien hQC, , (2007), 309-316 _. ~ " A ~" , 310 vO THANH NAM, PHAN TRUNG HUY ve khieri, da tri, nhap nhang de mo rong khai niem tich, tir do xay dung nhirng lap ma maio khia canh irng dung, bao mat dir lieu nho ap dung mot phirong phap ma hoa don tri (m9t ban ro cho ta mot ban ma) va lau dai nguy ca bi tham ma se tang boi cac tan cong xac swit dira tren mau thu hrorn boi doi phuang. Ma hoa da tri va bien dong (mot ban ro co the dira ra nhieu ban ma khac nhau ngau nhien va dQ dai co dan cling khac nhau) 180 mot tiep c~n tang dC?kho tharn ma Ion rat cao VI so mau thu diroc se 180 qua nho de co the st'r dung tan cong xac suat. Theo xu huang do, trong bai nay, vo'i co sa 180 tich dan hoi, trong do tich cua hai tu the nen 10-ihoac dan dai, da diroc giai thieu fan dau tien trong [10], cluing toi trmh bay m9t dang cua hinh thirc ma dan hoi dira tren ca sa dai so va ly thuyet do thi, va d~t quan tam nghien ciru tren lap cac ngon ngir chinh quy. co VA MA 2. TieH DAN Hal DAN Hal TREN Da TH~ Mo dau muc nay, bet xin nhiic 10-ikhai niern ve tich dan hoi va rna dan hoi dua tren phuong phap do thi, da diroc trinh bay lan dau trong [10]. Ta gioi han xem xet cac ngon ngir xay dung tir bang chir nhi phan B = {O, I} co d9 dai nhir nhau, X ~ Bk = {O, l}k. Y tirong xay dirng tich dan hoi la trong qua trinh ma hoa, tich cua cac tir khong 180 tich ghep nhir tich thong tlnro ng ma co the "co 10-i"hoac "keo dan" nghia la co tinh dan hoi. Trong muc nay, chung ta se st'r dung do thi de d~c tnrng khai niern tich dan hoi (duoc goi 180 thi xac dinh ma dan hoi}. do 80 thi ma dan hoi: cho tap Bk gorn 2k dinh. Moi dinh diroc gan ten boi xau k bit co gia tri tir den 2k - l. Tir moi dinh b = b1b2 . bk E Bk co 2 cung di den 2 dinh p, q co k - 1 bit dau trung voi k - 1 bit cuoi cua b. Cu the, cung tir dinh p = b1b2 . bk voi nhan d, d = 0 hay 1, se co dinh cuoi 180 = b2 . bkd. p ° Vi d u . Voi k = 3, ta co c10 thi 1110 ta cho .
