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Publié par | profil-urra-2012 |
Nombre de lectures | 8 |
Langue | English |
Extrait
a a ...a 0 10a +9a +1 2 1 1 2
8a +7a +6a +5a +4a +3a +2a + a 11 0−2435−6411−33 4 5 6 7 8 9 10
10a +9a +8a +7a +6a +5a +4a +3a +2a +a 10.0+9.2+8.4+1 2 3 4 5 6 7 8 9 10
7.3.+6.5+5.6+4.4+3.1+2.1+3 = 154 155 11 0−2435−6411−3
a a a ...a a +a +a +a +10 1 2 9 1 2 3 4
a + a + a + a + a + a 0 05 6 7 8 9 1
55811−2742
5+5+8+1+1+2+7+4+2 = 35 5
5+4+3+1+2+7+5+0+0+1 = 31
a 5+4+a +1+2+7+5+0+0+1 = 25+a3 3 3
0 a = 53
5451275001
0100 0101 0011 1101
a + a + a a + a a + a + a2 3 4 2 4 1 2 3
0100 1 1 1 0100111
0101 0 0 1 0101001
0011011 1101001
4
42 = 16 4 16
withaaignw1.awh,sucthirdinouhosenhcerisy-cdeoro,endsotherwithmeacoce.the(a)ordsFindthreethehecc,hec,k-digitwforsecondthethisZIP+4arectheothedeoZIP+4Universitynine-digitsucac.wAnswber.theOnemessageshasobtainedfordigitsk-digitIShec,cThe.2.rster.F1bsoum.nisISBNandcorrectcoaonenotcois.eredbordsumofne,desohaoTherenewmwithustsocinho.oseadditionaltheobtainasnthewc3.(a)hecdekthedigit,(b)andIsythehecZIPthe+4kcofordethe(includingbits,c20th.hecridak-digit)er.5431275001,correctis(explain)?secondIfandSoGroupbinarycoofisyorsorste,ouldSpringvthirdhasotowthatis.larlydethatowds.waseandtheIfage.ereinconrderecalltsag,scanoyd,ouyrecoordsvyeretheAnswcorrectIllinoicoade?aAnswendser.aThis,timewtheobtainsumhosenisis.So,ythisbinformation,divisibleeenlythatevcorrectnotumiserandas,.oFindtcoequalwhereforisbinarysumbTheumer.nAnswBNer?bbadding,csoktheusingnparitumhecbsumseranisk-digitnotccothatrerrecRememt;andwNAMEeAprilcaynnotFcor-AnswrectFthe8errortheunlesssumwQuizetheknoisw,whicthehisdigit;istheincorrectde(worde181don'tFhaMathvtheesumenough2007information).theHoisw,evtheer,isif;wtheedeknoordwtimethatUrbana-ChampumSimin,isobtainstthehteoonlydeincorrectordsdigit,tthenaw(b)eyknowwaskthattoitdmcoustwbforebinarysucshesthatlengthISBNusingcorrectabavermethobhoummanncothewIsw.uldyoubvibletodivismpute?enlyer.evareisofthatynot,messagescanlengthy,ouwcorrectwit?haIfeydoucomputeknocowwthatronlyPletheturnthirdpdigitisBA We first write 1010 in the relevant positions, then we add digits in such a
1 way that the number of 0’s and 1’s in each circle is even (see the figure above).00
Then we read the code word: 1010001.
1
00
1
C
BA
Circle A looks OK, but both B and C are incorrect; so we assume that the error
1 comes from the digit that is in both B and C, and this leads us to decode the 1 0
message as 1001 (when decoding, we no longer care about the error−detection digits).
0 11
1
C
BA This time, every circle looks OK; so we assume
that no transmission error was made, and we decode 1
0 1 the message as 1011.
1
10
0
C
hVwennthediagrammethomethoyd1101101todeterminedecoVdeso;eaccanhorofoftcohetfollo1011010wing(b)r4.1010.saeifyou(seecorrectlasterrorge,not)rmessageunfathomableordthedewtheIotodpicturesdiagramtoennthisthetUsesewhereUshou(a)d..)e1100100ceivtheedpawfoosomerreasondsoftsare(ifusethereincludeisrefusesanincludeerroroneinitthelmessage,.sayThis time, all three circles are incorrect; so we assume that the
11 incorrect digit is the one that belongs to all three circles, and decode 0
the message as 1110.
01 0
0