• Non ci sono risultati.

Using high frequency stock market index data to calculate, model and forecast realized return variance

N/A
N/A
Protected

Academic year: 2021

Condividi "Using high frequency stock market index data to calculate, model and forecast realized return variance"

Copied!
33
0
0

Testo completo

(1),N+, NWV,+5WAv W5AWANA, #,+A,A 6 ,W5. ,NW `Lh!?} @Tih , L 2ff%S. Nt?} O} 6hi^i?U) 5|LU! @h!i| W?_i #@|@ |L @*U*@|ic L_i* @?_ 6LhiU@t| +i@*3i_ +i|h? V@h@?Ui -Nj,   N6jA. #W 6W,5wc 5 #,W E6W.

(2) ** h}|t hitihi_ L T@h| Lu |t T@Tih 4@) Mi hiThL_Ui_ ? @?) uLh4 |L| Tih4ttL? Lu |i @|Lh. U 2ff +Li*  L4i? h?|i_ ? W|@*) ? Th* 2ff ,hLTi@? N?iht|) W?t|||i @_@ 6itL*@?@ WDffS 5@? #L4i?UL E6W W|@*).

(3) Xvlqj Kljk Iuhtxhqf| Vwrfn Pdunhw Lqgh{ Gdwd wr Fdofxodwh/ Prgho ) Iruhfdvw Uhdol}hg Uhwxuq Yduldqfh Urho F1D1 Rrphq. Devwudfw Wkh remhfwlyh ri wklv sdshu lv wr fdofxodwh/ prgho dqg iruhfdvw uhdol}hg yrodwlolw|/ xvlqj kljk iuhtxhqf| vwrfn pdunhw lqgh{ gdwd1 Wkh dssurdfk wdnhq glhuv iurp wkh h{lvwlqj olwhudwxuh lq vhyhudo dvshfwv1 Iluvw/ lw lv vkrzq wkdw wkh ghfd| ri wkh vhuldo ghshqghqfh ri kljk iuhtxhqf| uhwxuqv zlwk wkh vdpsolqj iuhtxhqf|/ lv frqvlvwhqw zlwk dq DUPD surfhvv xq0 ghu whpsrudo djjuhjdwlrq1 Wklv qglqj kdv lpsruwdqw lpsolfdwlrqv iru wkh prghoolqj ri kljk iuhtxhqf| uhwxuqv dqg wkh rswlpdo fkrlfh ri vdp0 solqj iuhtxhqf| zkhq fdofxodwlqj uhdol}hg yrodwlolw|1 Vhfrqg/ prwlydwhg e| wkh rxwfrph ri vhyhudo whvw vwdwlvwlfv iru orqj phpru| lq uhdol}hg yrodwlolw|/ lw lv irxqg wkdw wkh uhdol}hg yrodwlolw| vhulhv fdq eh prghoohg dv dq DUILPD surfhvv1 Vljqlfdqw h{rjhqrxv uhjuhvvruv lqfoxgh odjjhg uhwxuqv dqg frqwhpsrudqhrxv wudglqj yroxph1 Ilqdoo|/ wkh DUILPD*v iruhfdvwlqj shuirupdqfh lv dvvhvvhg lq d vlpxodwlrq vwxg|1 Dowkrxjk lw rxwshuirupv uhsuhvhqwdwlyh JDUFK prghov/ wkh vlpsolflw| dqg h{lelolw| ri wkh JDUFK pd| rxwzhljk wkh prghvw jdlq lq iruhfdvwlqj shuirupdqfh ri wkh pruh frpsoh{ dqg gdwd lqwhqvlyh DUILPD prgho1 Nh|zrugv= Kljk Iuhtxhqf| Gdwd> Uhdol}hg Yrodwlolw|> Rswlpdo Vdp0 solqj Iuhtxhqf|> Whpsrudo Djjuhjdwlrq> Orqj Phpru|1 MHO Frghv= F84/ F85/ F86/ J45/ J46  Hxurshdq. Xqlyhuvlw| Lqvwlwxwh/ Ghsduwphqw ri Hfrqrplfv Yld ghl Urffhwwlql </ 83349 Vdq Grphqlfr gl Ilhvroh/ Lwdo|1 Hpdlo= urho1rrphqClxh1lw1 Wklv sdshu kdv juhdwo| ehqhwwhg iurp glvfxvvlrqv zlwk Iudqn Glherog/ Pdufhor Ihuqdqghv/ Jhrujh Mldqj/ Pdun Odxhu/ Ehqw Vûuhqvhq dqg Mxdq Wrur1 L dp sduwlfxoduo| judwhixo iru pdq| ghwdlohg frpphqwv dqg vxjjhvwlrqv ri Vûuhq Mrkdqvhq1 L wkdqn Orjlfdo Lqirupdwlrq Pdfklqhv/ Lqf1 zkr nlqgo| surylghg wkh gdwd qhhghg iru wkh dqdo|vlv1 Wkh uhvhdufk zdv sduwo| vxssruwhg e| wkh Qhwkhuodqgv Rujdql}dwlrq iru Vflhqwlf Uhvhdufk +QZR, judqwv VLU 4507343 dqg U079077:1 Dq| huuruv duh plqh1.

(4) 4. Lqwurgxfwlrq. D fuxfldo hohphqw lq wkh wkhru| dqg sudfwlfh ri ghulydwlyh sulflqj dqg qdqfldo ulvn pdqdjhphqw lv wkh hvwlpdwlrq dqg prghoolqj ri dvvhw uhwxuq yduldqfh1 Erwk wkh Vwrfkdvwlf Yrodwlolw| dqg wkh Dxwruhjuhvvlyh Frqglwlrqdo Khwhurvnhgdvwlflw| +DUFK, fodvv ri prghov kdyh ehfrph zlgho| hvwdeolvkhg dqg vxffhvvixo ds0 surdfkhv/ lq erwk wkh wkhruhwlfdo dqg wkh hpslulfdo olwhudwxuh/ wr wkh prghoolqj ri wkh yduldqfh surfhvv1 Wkh remhfwlyh ri wklv sdshu/ krzhyhu/ lv wr h{soruh wkh h{whqw wr zklfk wkh xvh ri wkh lqfuhdvlqjo| dydlodeoh lqwud0gdlo| gdwd rq qdq0 fldo dvvhwv fdq eh xvhg wr lpsuryh ru idflolwdwh wkh hvwlpdwlrq dqg prghoolqj ri uhwxuq yduldqfh1 Wr wklv hqg Phuwrq +4<;3, qrwhv wkdw wkh yduldqfh +ryhu d {hg lqwhuydo, ri dq llg udqgrp yduldeoh fdq eh hvwlpdwhg duelwudulo| dffxudwh e| wkh vxp ri vtxduhg uhdol}dwlrqv/ surylghg wkdw wkh gdwd lv dydlodeoh dw d vx!flhqwo| kljk vdpsolqj iuhtxhqf|1 Hpslulfdo vwxglhv/ vxfk dv Iuhqfk/ Vfkzhuw dqg Vwdp0 edxjk +4<;:,/ Kvlhk +4<<4,/ Wd|oru dqg [x +4<<:,/ Dqghuvhq dqg Eroohuvohy +4<<;,/ pdnh xvh ri wklv lqvljkw dqg hpsor| lqwud0gdlo| uhwxuq gdwd wr hvwlpdwh gdlo| uhwxuq yduldqfh e| vlpso| vxpplqj xs vtxduhg lqwud0gdlo| uhwxuqv1 Lq wkh olwhudwxuh wklv yduldqfh phdvxuh lv uhihuuhg wr dv uhdol}hg yduldqfh1 Lq d uhfhqw sdshu Dqghuvhq hw1 do1 +5333d, kdv vkrzq lq d frqwlqxrxv wlph vhw0 wlqj wkdw zkhq wkh uhwxuq surfhvv iroorzv d vshfldo vhpl0pduwlqjdoh/ wkh vxp ri vtxduhg uhwxuqv zloo |lhog d frqvlvwhqw hvwlpdwh iru wkh lqwhjudwhg yduldqfh +vtxduhg yrodwlolw|, ri wkh uhwxuq surfhvv= Wkh phfkdqlfv duh vlpsoh 0 zh frpsxwh gdlo| uhdol}hg yrodwlolw| vlpso| e| vxpplqj xs vtxduhg uhwxuqv 0 exw wkh wkhru| lv ghhs= e| vdpsolqj lqwud0gd| uhwxuqv vx!flhqwo| iuhtxhqwo|/ wkh uhdol}hg yrodwlo0 lw| fdq eh pdgh duelwudulo| forvh wr wkh xqghuo|lqj lqwhjudwhg yrodwlo0 lw|/ wkh lqwhjudo ri lqvwdqwdqhrxv yrodwlolw| ryhu wkh lqwhuydo ri lq0 whuhvw/ zklfk lv d qdwxudo yrodwlolw| phdvxuh 0 +Dqghuvhq hw1 do1 +5333d,, Dowkrxjk wkh zrun e| Phuwrq +4<;3, dqg Dqghuvhq hw1 do1 +5333d, lv wdnhq dv d vwduwlqj srlqw iru wkh fdofxodwlrq dqg dqdo|vlv ri wkh uhdol}hg ydul0 dqfh phdvxuh/ wkh suhvhqw vwxg| lv glvwlqjxlvkhg iurp wkh h{lvwlqj olwhudwxuh lq vhyhudo zd|v1 Iluvw dqg iruhprvw/ wkh fkrlfh ri vdpsolqj iuhtxhqf| dqg wkh lpsdfw wkdw pdunhw plfur vwuxfwxuh lqgxfhg dxwrfruuhodwlrqv kdyh rq uhdol}hg yduldqfh duh glvfxvvhg lq frqvlghudeoh ghwdlo> lvvxhv wr zklfk kdv ehhq sdlg vxu0 sulvlqjo| olwwoh dwwhqwlrq vr idu1 Wkh vhuldo ghshqghqfh ri kljk iuhtxhqf| uhwxuqv 4.

(5) lv dqdo|}hg dqg lw lv irxqg wkdw wkh dxwrfruuhodwlrq vwuxfwxuh +pdjqlwxgh dqg udwh ri ghfd|, ri uhwxuqv dw glhuhqw vdpsolqj iuhtxhqflhv lv frqvlvwhqw zlwk wkh uhvxowv rq whpsrudo djjuhjdwlrq ri dq DUPD surfhvv1 Wklv qglqj kdv lpsruwdqw lpsolfdwlrqv iru wkh fkrlfh ri rswlpdo vdpsolqj iuhtxhqf| zkhq fdo0 fxodwlqj wkh uhdol}hg yduldqfh phdvxuh1 43 |hduv ri plqxwh e| plqxwh IWVH0433 lqgh{ uhwxuqv duh hpsor|hg wr looxvwudwh wkdw zkhq wkh vdpsolqj iuhtxhqf| lv qrw fduhixoo| fkrvhq/ vroho| vxpplqj xs vtxduhg uhwxuqv fdq vhulrxvo| xqghu0 ru ryhuhvwlpdwh wkh dyhudjh gdlo| uhwxuq yduldqfh1 Vhfrqg/ d uhdol}hg yduldqfh vh0 ulhv iru wkh IWVH0433 lqgh{ uhwxuqv lv frqvwuxfwhg xvlqj 58 plqxwh uhwxuq gdwd zklfk lv prghoohg vxevhtxhqwo|1 Lw lv irxqg wkdw dq DUILPD vshflfdwlrq/ lqfoxglqj vrph h{rjhqrxv yduldeohv vxfk dv odjjhg uhwxuqv dqg wudglqj yroxph/ prghov wkh vhulhv zhoo1 Wklv h{whqgv wkh zrun ri Dqghuvhq dqg Eroohuvohy +4<<;, zklfk xvhv wkh uhdol}hg yduldqfh hvwlpdwhv iru hydoxdwlrq ri wkh iruhfdvwlqj shu0 irupdqfh ri wkhlu JDUFK prgho ru wkdw ri Dqghuvhq hw1 do1 +5333d/e, zklfk dqdo|}hv wkh surshuwlhv ri wkh gdwd1 Wkh uhjuhvvlrq frh!flhqwv ri wkh odjjhg uh0 wxuq yduldeoh duh xvhg wr whvw iru wkh suhvhqfh ri Eodfn*v ohyhudjh hhfw1 Wklug dqg qdoo|/ wkh iruhfdvwlqj shuirupdqfh ri wkh DUILPD prgho iru uhdol}hg ydul0 dqfh lv dvvhvvhg lq d vlpxodwlrq vwxg|1 Wkh uhvxowv lqglfdwh wkdw wkh DUILPD prgho iru uhdol}hg yduldqfh rxwshuirupv uhsuhvhqwdwlyh JDUFK0fodvv prghov1 Lw lv qrwhg/ krzhyhu/ wkdw wkh vlpsolflw| ri wkh JDUFK wrjhwkhu zlwk lwv h{lelo0 lw| wr dffrxqw iru shuvlvwhqfh lq uhwxuq yduldqfh/ pd| rxwzhljk wkh prghvw jdlq lq iruhfdvwlqj shuirupdqfh ri wkh pruh frpsoh{ dqg gdwd lqwhqvlyh DUILPD prgho1 Wkh uhpdlqghu ri wklv sdshu lv vwuxfwxuhg dv iroorzv1 Vhfwlrq 5 glvfxvvhv wkh fdofxodwlrq ri uhdol}hg yduldqfh dqg sursrvhv d prgho iru gdlo| dv zhoo dv lqwud0gdlo| uhwxuqv1 Wkh uhdol}hg yduldqfh vhulhv lv frqvwuxfwhg dqg d fduhixo dqdo|vlv vkrzv wkdw prvw ri wkh vw|ol}hg idfwv/ dv grfxphqwhg lq wkh uhfhqw olwhudwxuh/ fdq eh frquphg iru wkh IWVH0433 lqgh{ gdwd1 Vhfwlrq 6 prghov uhdol}hg yduldqfh dv dq DUILPD surfhvv1 Vhfwlrq 7 frpsduhv wkh iruhfdvw0 lqj shuirupdqfh ri wkh DUILPD prgho iru uhdol}hg yduldqfh zlwk frqyhqwlrqdo JDUFK w|sh prghov1 Vhfwlrq 8 frqfoxghv1. 5. Uhdol}hg Yduldqfh. Wkh whup uhdol}hg yduldqfh uhihuv wr wkh vxp ri vtxduhg lqwud0shulrg uhwxuqv/ ehlqj dq hvwlpdwru iru wkh dyhudjh ru lqwhjudo ri lqvwdqwdqhrxv yduldqfh ryhu wkh lqwhuydo ri lqwhuhvw1 Lq idfw/ lq d frqwlqxrxv wlph iudphzrun/ lw kdv ehhq vkrzq 5.

(6) e| Dqghuvhq hw1 do1 +5333d, wkdw zkhq wkh uhwxuq surfhvv lv dvvxphg wr iroorz d vshfldo vhpl0pduwlqjdoh wkh uhdol}hg yduldqfh phdvxuh fdq eh pdgh duelwudulo| forvh wr wkh lqwhjudo ri lqvwdqwdqhrxv yduldqfh/ surylghg wkdw wkh lqwud0shulrg uhwxuqv duh vdpsohg dw d vx!flhqwo| kljk iuhtxhqf|1 Lq wkh suhvhqw frqwh{w/ krzhyhu/ wkh irfxv zloo eh rq d glvfuhwh wlph prgho zklfk kdv wkh dgydqwdjh wkdw wkh lpsdfw ri pdunhw plfur vwuxfwxuh hhfwv/ suhvhqw lq uhwxuqv vdpsohg dw kljk iuhtxhqf|/ rq wkh uhdol}hg yduldqfh phdvxuh fdq eh dqdo|}hg lq d vwudljkwiruzdug idvklrq1 Lw zloo eh vkrzq wkdw zkhq lqwud0shulrg uhwxuqv duh vhuldoo| fruuhodwhg/ wkh uhdol}hg yduldqfh phdvxuh zloo |lhog d eldvhg hvwlpdwru ri wkh dyhudjh wuxh yduldqfh ryhu wkh lqwhuydo ri lqwhuhvw1 Wkurxjkrxw wkh uhpdlqghu ri wkh sdshu wkh lqwhuydo ri lqwhuhvw lv vhw wr rqh wudglqj gd|1 Ohw 7|c ghqrwh wkh  | lqwud gd|| sulfh ri wkh vhfxulw| xqghu frqvlghudwlrq |cK' 1 Xqghu wkh dvvxpswlrq dqg [|c eh wkh vljpd hog jhqhudwhg e| i7@cK j@@' '3"cK'f ri  htxdoo| wlph0vsdfhg lqwud0gdlo| revhuydwlrqv ri 7 E ' c    c / wkh gdlo| uhwxuq lv ghqhg dv= -| ' *? 7|c  *? 7|3c c | ' c    c A 1 Dw vdpsolqj iuhtxhqf| sc zh fdq frqvwuxfw s ' s lqwud0gdlo| uhwxuqv= -sc|c ' *? 7|cs  *? 7|cE3s c. iru  ' c    c s dqg 7|cf ' 7|3c 1 Lq wkh iroorzlqj/ lw lv dvvxphg wkdw wkh dvvhw*v +h{fhvv, uhwxuq dw wkh gdlo| iuhtxhqf| fdq eh fkdudfwhul}hg dv= -| ' j | 0| c. zkhuh 0| llg Q Efc  dqg j 2| uhsuhvhqwv wkh gd|| uhwxuq yduldqfh1 Qrwh wkdw .[ f d-2| o ' j 2| dqg wkdw T[ f d-|2 o ' 2j e| 1 Qrz frqvlghu wkh vlwxdwlrq lq zklfk lqwud0gdlo| uhwxuqv/ dw vdpsolqj iuhtxhqf| s / duh xqfruuhodwhg dqg fdq eh fkdudfwhul}hg dv= -sc|c ' j sc|c 0sc|c c   S zkhuh 0sc|c llg Q fc s3 dqg -| ' ' -sc|c e| ghqlwlrq1 Vlqfh lqwud0gdlo| kS l  2 uhwxuqv duh dvvxphg wr eh xqfruuhodwhg/ lw gluhfwo| iroorzv wkdw .[ f ' -sc|c ' S  .[ f d-2| o dqg khqfh j 2| ' s3 ' j 2sc|c 1 Dv d uhvxowv/ wzr xqeldvhg hvwlpdwruv iru wkh dyhudjh gd|| uhwxuq yduldqfh h{lvw/ qdpho| wkh vtxduhg gd|| uhwxuq dqg wkh vxp ri vtxduhg lqwud gd|| uhwxuqv1 Lw lv qrwhg/ krzhyhu/ wkdw zkloh T[ f d-|2 o ' 2j e| wkh iroorzlqj krogv= 53 42 6   3   [ [ [ [ j 2sc|c 02sc|c D 8 '

(7) s32 jesc|c n 2s32 j 2sc|c j2sc|c c .[ f 7C |c. |c. s. s. |c. s. |c. |c. s. |c. '. s. '. 6. s. s. '  'n.

(8) dqg wkhuhiruh= 5 6 5 62    e 2 [ [ jsc|c   2 7[ j sc|c 8 2 8' 2 s -sc|c. ' T[ f -|2 1 T[ f 7 s ' s s ' s ' s. s. s. |c. |c. Lq zrugv/ wkh dyhudjh gdlo| uhwxuq yduldqfh fdq eh hvwlpdwhg pruh dffxudwho| e| vxpplqj xs vtxduhg lqwud0gdlo| uhwxuqv udwkhu wkdq fdofxodwlqj wkh vtxduhg gdlo| uhwxuq1 Lq dgglwlrq/ zkhq uhwxuqv duh revhuyhg +dqg xqfruuhodwhg, dw dq| duelwudu| vdpsolqj iuhtxhqf|/ lw lv srvvleoh wr khvwlpdwh wkh l dyhudjh gdlo| S 2 yduldqfh iuhh ri phdvxuhphqw huuru dv *4 <" T[ f ' -sc|c ' f Wkh rqo| +zhdn, uhtxluhphqw rq wkh g|qdplfv ri wkh lqwud0gdlo| uhwxuq yduldqfh iru wkh S deryh wr krog lv wkdw ' j esc|c 2 snS zkhuh f  S 1 Ilqdoo|/ qrwh wkdw dowkrxjk wkh gdlo| uhdol}hg yduldqfh phdvxuh hpsor|v lqwud0gdlo| uhwxuq gdwd/ wkhuh lv qr qhhg qru jdlq wr wdnh wkh +zhoo grfxphqwhg, surqrxqfhg lqwud0 gd| yduldqfh sdwwhuq ri wkh uhwxuq surfhvv lqwr dffrxqw1 Wklv ihdwxuh ri wkh uhdol}hg yduldqfh phdvxuh frqwudvwv vkduso| zlwk srsxodu sdudphwulf yduldqfh prghov zklfk jhqhudoo| uhtxluh wkh h{solflw prghoolqj rq lqwud0gdlo| uhjxodulwlhv lq uhwxuq yduldqfh1 s. s. |c. s. Wkh irfxv lq wkh uhpdlqghu ri wklv vhfwlrq zloo eh rq krz wkh lqfuhdvlqjo| dydlodeoh kljk iuhtxhqf| qdqfldo gdwd fdq eh xvhg iru wkh sxusrvh ri yduldqfh hvwlpdwlrq1 Lq sduwlfxodu/ plqxwh e| plqxwh IWVH0433 lqgh{ ohyho gdwd4 zloo eh xvhg wr lqyhvwljdwh zkhwkhu wkh phwkrg ri fdofxodwlqj wkh uhdol}hg yduldqfh phdvxuh/ ehlqj wkh vxp ri vtxduhg lqwud0gdlo| uhwxuqv/ zloo |lhog vdwlvidfwru| uhvxowv1 Wr wklv hqg/ wkh ghfrpsrvlwlrq ri wkh gdlo| uhwxuq lqwr wkh vxp ri s lqwud0gdlo| uhwxuqv fdq eh xvhg wr ghulyh wkh iroorzlqj h{suhvvlrq= 5 62 s s [ s 3 s [ [ [ 2 2 7 8 -| ' -sc|c ' -sc|c n 2 -sc|c -sc|c . '. '. '  'n. +4,. Zkhq wkh dvvxpswlrq ri xqfruuhodwhg uhwxuqv dw vdpsolqj iuhtxhqf| s lv vdwlvhg/ wkh vhfrqg whup rq wkh uljkw kdqg vlgh ri h{suhvvlrq E lv }hur lq h{shfwdwlrq dqg wkh uhdol}hg yduldqfh phdvxuh zloo wkhuhiruh |lhog dq xqeldvhg hvwlpdwh ri wkh dyhudjh gd|| uhwxuq yduldqfh1 Krzhyhu/ dv qrwhg e|/ iru h{0 dpsoh/ Iuhqfk hw1 do1 +4<;:,/ zkhq wkh uhwxuqv duh srvlwlyho| fruuhodwhg/ vroho| 4. Wkh gdwdvhw frqwdlqv plqxwh e| plqxwh gdwd rq wkh IWVH0433 lqgh{ ohyho/ vwduwlqj Pd| 4/ 4<<3 dqg hqglqj Mdqxdu| 44/ 53331 Wudglqj krxuv duh 3;=63049=63/ Prqgd| wr Iulgd| xqwlo Vhswhpehu 47/ 4<<7 dqg ;=33049=63 diwhuzdugv1 Wkh wrwdo qxpehu ri revhuydwlrqv lv mxvw ryhu 414 ploolrq1. 7.

(9) vxpplqj xs vtxduhg uhwxuqv zloo xqghuhvwlpdwh wkh dyhudjh gdlo| yduldqfh> wkh furvv pxowlsolfdwlrq ri uhwxuqv zloo eh srvlwlyh rq dyhudjh1 Wkh uhyhuvh zloo rffxu iru qhjdwlyho| dxwrfruuhodwhg uhwxuqv1 Wr looxvwudwh wklv/ d gdwdvhw frqwdlqlqj plqxwh e| plqxwh gdwd rq wkh ohyho ri wkh IWVH0433 vwrfn pdunhw lqgh{ lv hpsor|hg wr fdofxodwh wkh 43 |hdu dyhudjh +4<<305333, ri wkh wzr whupv rq wkh uljkw kdqg vlgh ri h{suhvvlrq E iru vdpsolqj iuhtxhqflhv ehwzhhq 4 dqg 78 plqxwhv1 Wkh uhvxowv duh glvsod|hg lq Iljxuh 414 wrjhwkhu zlwk wkh 43 |hdu dyhudjh vtxduhg gdlo| uhwxuqv +grwwhg olqh,1 Lw lv fohdu wkdw wkh uvw whup/ wkh uhdol}hg yduldqfh phdvxuh/ lqfuhdvhv zlwk d ghfuhdvh lq vdpsolqj iuhtxhqf| zkloh wkh vhfrqg whup/ wkh vxppdwlrq ri furvv pxowlsolhg uhwxuqv/ ghfuhdvhv1 Pruhryhu/ wkh vxp ri wkh wzr whupv lv/ dv rqh zrxog h{shfw/ urxjko| frqvwdqw1 Wkh srvlwlylw| ri wkh vhfrqg whup lqglfdwhv wkdw wkh IWVH0433 uhwxuqv duh srvlwlyho| fruuhodwhg/ lqwurgxflqj d grzqzdug eldv lqwr wkh uhdol}hg yduldqfh phdvxuh +xs wr 68( zkhq xvlqj plqxwh e| plqxwh gdwd$,/ zkloh lwv ghfuhdvlqj sdwwhuq ghprqvwudwhv wkdw wklv ghshqghqfh/ dqg frqvhtxhqwo| wkh eldv/ glplqlvkhv zkhq vdpsolqj lv grqh ohvv iuhtxhqw1 Wklv whup fdq wkhuhiruh eh lqwhusuhwhg dv wkh dxwrfryduldqfh lqgxfhg eldv ri wkh uhdol}hg yduldqfh phdvxuh dqg zloo eh uhihuuhg wr dv wkh dxwrfryduldqfh eldv idfwru lq wkh uhpdlqghu ri wkh sdshu1 Dowkrxjk/ lq wkh frqwh{w ri h!flhqw pdunhwv/ wkh qglqj ri fruuhodwhg lqwud0gdlo| uhwxuqv pd| dw uvw vljkw dsshdu sx}}olqj/ lw kdv d vhqvleoh h{sodqd0 wlrq lq wkh frqwh{w ri wkh pdunhw plfurvwuxfwxuh olwhudwxuh5 1 Rqh ri wkh prvw surplqhqw k|srwkhvhv zklfk fdq eh xvhg wr h{sodlq wkh revhuyhg srvlwlyh dx0 wrfruuhodwlrq lq vwrfn lqgh{ uhwxuqv lv qrq0v|qfkurqrxv wudglqj1 Wkh edvlf lghd lv wkdw zkhq lqglylgxdo vwrfnv frqwdlqhg lq dq lqgh{ gr qrw wudgh vlpxowdqh0 rxvo|/ wkh frqwhpsrudqhrxv srvlwlyh dxwrfruuhodwlrq dprqj wkh frpsrqhqwv zloo lqgxfh vhuldo fruuhodwlrq lq wkh lqgh{ uhwxuqv1 Lqwxlwlyho|/ zkhq wkh lqgh{ frp0 srqhqwv lqfrusrudwh qrq0v|qfkurqrxvo| wkh vkrfnv wr d frpprq idfwru gulylqj wkhlu sulfh/ wklv zloo uhvxow lq d vhtxhqfh ri fruuhodwhg sulfh fkdqjhv dw wkh djjuh0 jdwhg ru lqgh{ sulfh ohyho1 Wklv skhqrphqrq/ zklfk lv frqvlvwhqw zlwk wkh deryh hpslulfdo qglqjv6 / reylrxvo| glvdsshduv zkhq vdpsolqj iuhtxhqf| ghfuhdvhv1 5. Vhh h1j1 Fdpsehoo/ Or dqg PdfNlqod| +4<<;,/ Ohtxhx{ +4<<<,/ Pdgkdydq +5333, ru Zrrg +5333,1 6 Wkh uhyhuvh zrxog rffxu iru d vlqjoh dvvhw1 Wkh vhuldo fruuhodwlrqv ri uhwxuqv/ li suhvhqw/ zrxog olnho| eh qhjdwlyh wkhuhe| lqwurgxflqj dq xszdug eldv lq wkh uhdol}hg yduldqfh phdvxuh1 Wkh qhjdwlyh dxwrfruuhodwlrq fdq eh dwwulexwhg wr wkh elg0dvn erxqfh> lq d pdunhw zkhuh qr qhz lqirupdwlrq duulyhv/ wkh vwrfn sulfh lv h{shfwhg wr erxqfh ehwzhhq wkh elg dqg wkh dvn sulfh zkhqhyhu d wudgh rffxuv1. 8.

(10) Lw kdv ehhq vkrzq wkdw dyhudjh gdlo| uhwxuq yduldqfh fdq eh hvwlpdwhg frqvlvwhqwo| e| wkh uhdol}hg yduldqfh phdvxuh/ surylghg wkdw wkh lqwud0gdlo| uh0 wxuqv duh vhuldoo| xqfruuhodwhg1 Zkhq wkh lqwud0gdlo| uhwxuqv duh fruuhodwhg/ uhdol}hg yduldqfh zloo hlwkhu ryhuhvwlpdwh +zlwk qhjdwlyh fruuhodwlrq, ru xqghu0 hvwlpdwh +srvlwlyh fruuhodwlrq, wkh dyhudjh gdlo| uhwxuq yduldqfh1 Fruuhfwlqj iru wkh eldv whup/ lw lv nqrzq diwhu doo/ lv qrw ghvludeoh dv wklv lv htxlydohqw wr xvlqj wkh vtxduhg gdlo| uhwxuq wr hvwlpdwh gdlo| uhdol}hg yduldqfh1 Khqfh/ zkhq wkh lqwud0gdlo| uhwxuq gdwd dw wkh kljkhvw iuhtxhqf| dydlodeoh lv vhuldoo| fruuhodwhg/ rqh zloo qhhg wr djjuhjdwh wkh uhwxuqv grzq wr d iuhtxhqf| dw zklfk wkh fruuhodwlrq kdv glvdsshduhg1 Sorwwlqj erwk wkh vxp ri vtxduhg lqwud0gdlo| uhwxuqv dqg wkh dxwrfryduldqfh eldv idfwru yhuvxv wkh vdpsolqj iuhtxhqf|/ dv lv grqh lq Iljxuh 414/ suryhv d yhu| khosixo dqg hdvlo| lpsohphqwdeoh vwudwhj| wr ghwhuplqh wkh iuhtxhqf| dw zklfk wkh fruuhodwlrq kdv glhg r1 Wkh rswlpdo vdpsolqj iuhtxhqf| lv fkrvhq dv wkh kljkhvw dydlodeoh iuhtxhqf| iru zklfk wkh dxwrfryduldqfh eldv whup kdv glvdsshduhg1 Edvhg rq wkhvh revhuydwlrqv/ wkh vdpsolqj iuhtxhqf| iru hvwlpdwlqj uhdol}hg yduldqfh zloo eh vhw wr 58 plqxwhv +s ' 2D,1. 514. Vhuldo Fruuhodwlrq/ Wlph Djjuhjdwlrq ) Vdpsolqj Iuhtxhqf|. Sulru wr wkh hvwlpdwlrq dqg dqdo|vlv ri uhdol}hg yduldqfh/ d forvhu orrn lv wdnhq dw wkh dxwrfryduldqfh eldv whup lq uhodwlrq wr wkh g|qdplf surshuwlhv ri wkh lqwud0gdlo| uhwxuqv dw glhuhqw vdpsolqj iuhtxhqflhv1 Wdeoh L +dqg Iljxuh 414, uhsruwv vrph ghvfulswlyh vwdwlvwlfv iru wkh IWVH0433 uhwxuq gdwd dw glhuhqw vdpsolqj iuhtxhqflhv1 Erwk wkh rughu dqg wkh pdjqlwxgh ri wkh dxwrfruuhod0 wlrqv ghfuhdvh zlwk d ghfuhdvh lq vdpsolqj iuhtxhqf|1 Wkh Er{0Omxqj vwdwlvwlf frphv grzq iurp durxqg ;33 iru plqxwh gdwd/ wr durxqg 53 iru gdlo| gdwd +wkh <8( fulwlfdo ydoxh ri wklv whvw lv 4;164,1 Wkh Gxuelq Zdwvrq whvw vwdwlvwlf lq0 fuhdvhv iurp derxw 419 iru wkh plqxwh gdwd wr 513 iru wkh gdlo| gdwd1 Ilqdoo|/ lw lv qrwhg wkdw wkh uvw 53 dxwrfruuhodwlrqv fdofxodwhg iru wkh plqxwh e| plqxwh gdwd dsshdu vljqlfdqw zkloh rqo| wkh uvw rughu dxwrfruuhodwlrq ri gdlo| gdwd lv vljqlfdqw1 Wkhvh qglqjv vxjjhvw wkdw d uhdolvwlf vwdwlvwlfdo prgho iru lqwud0 gdlo| uhwxuqv vkrxog kdyh d pruh h{leoh vwuxfwxuh wkdq wkh vwdqgdug prgho iru gdlo| uhwxuqv1 Lq wkh uhpdlqghu ri wklv vhfwlrq lw zloo eh vkrzq wkdw prghoolqj lqwud0gdlo| uhwxuqv dv dq DUPD surfhvv lv d qdwxudo dqg/ dv lw wxuqv rxw/ vxf0 fhvvixo fkrlfh iru lw lv zhoo vxlwhg wr dffrxqw iru wkh vhuldo ghshqghqfh ri uhwxuqv dw ydulrxv vdpsolqj iuhtxhqflhv1 Iurp d pdunhw plfur vwuxfwxuh srlqw ri ylhz/ 9.

(11) wkh DU sduw zloo dujxdeo| eh deoh wr fdswxuh dq| dxwrfruuhodwlrq lqgxfhg e| qrq0v|qfkurqrxv wudglqj zkloh wkh PD sduw zloo dffrxqw iru srwhqwldo qhjdwlyh uvw rughu dxwrfruuhodwlrq lqgxfhg e| wkh elg dvn erxqfh1 Pruhryhu/ zlwklq wklv iudphzrun lw fdq eh vkrzq wkdw wkh ghfuhdvlqj rughu dqg pdjqlwxgh ri dxwrfru0 uhodwlrqv zlwk wkh vdpsolqj iuhtxhqf| lv d frqvhtxhqfh ri whpsrudo djjuhjdwlrq ri wkh uhwxuq surfhvv1 Vxssrvh wkdw uhwxuqv dw wkh kljkhvw vdpsolqj iuhtxhqf|/ - +wkh | vxevfulsw lv prphqwdulo| gursshg iru frqyhqlhqfh,/ fdq eh ghvfulehg dv dq DUPD+s/t, surfhvv= k Eu -c ' q Eu 0c c zkhuh k Eu dqg q Eu duh odj sro|qrpldov ri ohqjwkv R dqg ^ uhvshfwlyho|1 Frq0 vlghu wkh fdvh zkhuh doo wkh uhflsurfdov ri wkh urrwv ri k Eu ' f/ ghqrwhg e| w c c wR / olh lqvlgh wkh xqlw flufoh1 Wkh prgho wkurxjk zklfk wkh uhwxuqv dw dq duelwudu| vdpsolqj +ru djjuhjdwlrq, iuhtxhqf| fdq eh uhsuhvhqwhg lv ghulyhg xvlqj wkh uhvxowv ri Zhl +4<;4, rq whpsrudo djjuhjdwlrq7 +vhh dsshqgl{ iru d vxppdu|,1 Lq sduwlfxodu/ zkhq - iroorzv dq DUPD+s/t, surfhvv dv jlyhq deryh/ wkh uhwxuqv vdpsohg dw iuhtxhqf| s / ghqrwhg e| -s / fdq eh uhsuhvhqwhg e| dq DUPD+s/u, surfhvv= R  R  \ \   ws us   us s s   w u -sc ' q Eu 0sc c   w u   u   '  '. S 3 zkhuh o htxdov wkh lqwhjhu sduw ri R n ^3s R / 0sc ' s 'f 0cs3 1 Gxh wr wkh lq0 yhuwlelolw| ri wkh DU sro|qrpldo/ wkh deryh prgho fdq eh zulwwhq dv dq PDE4

(12) " surfhvv zlwk sdudphwhuv   'f dqg f ' 1 Ohw )s ghqrwh wkh | dxwrfr0 yduldqfh ri wkh whpsrudoo| djjuhjdwhg uhwxuqv dw iuhtxhqf| s / iru zklfk lw wxuqv rxw wkdw= 53 43 46   n s " [ [ [ 7C  D C  D8 c +5, )s ' . d-sc -sc3 o 2  'f. 3. '4@ Efc s n. 3. ' nns E . Dv wkh   frh!flhqwv ghfd| h{srqhqwldoo| idvw zlwk / wkh vhuldo fruuhodwlrq glvdsshduv xqghu whpsrudo djjuhjdwlrq1 Wr vhh wklv/ ohw   ' B  iru mBm  dqg  vrph srvlwlyh frqvwdqw1 Lw fdq qrz eh vkrzq wkdw= 5 6  n s  " [ [ [ 2 s  8 s E3 7 ) 2 B B 

(13) B E  B  'f 'f ' ns E3 7. Whpsrudo djjuhjdwlrq iru DUPD prghov lv glvfxvvhg lq Euhzhu +4<:6,/ Wldr +4<:5,/ Zhl +4<;4,/ Zhlvv +4<;7, dqg wkh YDUILPD lq Pdufhoolqr +4<<<,1. :.

(14) iurp zklfk lw fdq eh vhhq wkdw wkh vhuldo fruuhodwlrq glvdsshduv zkhq hlwkhu wkh vdpsolqj iuhtxhqf|/ s / ru wkh glvsodfhphqw/ / lqfuhdvhv1 Lq idfw/ Zhl +4<;4, kdv vkrzq wkdw wkh olplw prgho ri dq DUPD+s/t, surfhvv xqghu whpsrudo dj0 juhjdwlrq lv dq DUPD+3/3, ru htxlydohqwo| zklwh qrlvh1 Qrwh wkdw wkhvh wkhruhwlfdo surshuwlhv ri wkh DUPD surfhvv dsshdu yhu| pxfk lq dffrugdqfh zlwk wkh uhsruwhg hpslulfdo surshuwlhv ri wkh uhwxuq surfhvv dw glhuhqw vdpsolqj iuhtxhqflhv1 Pruh vshflfdoo|/ dw kljk vdpsolqj iuhtxhq0 flhv wkh DUPD prgho fdq dffrxqw iru wkh revhuyhg vhuldo ghshqghqfh zkloh dw orzhu vdpsolqj iuhtxhqflhv wkhvh ghshqghqflhv glh r dv d frqvhtxhqfh ri whpsrudo djjuhjdwlrq ri wkh uhwxuq surfhvv1 Lq dgglwlrq/ dv wkh olplw prgho ri wkh DUPD+s/t, prgho lv dq DUPD+3/3, xqghu whpsrudo djjuhjdwlrq/ wkh prgho vshflfdwlrq iru uhwxuqv dw wkh lqwud0gdlo| iuhtxhqf| grhv qrw qhfhvvdulo| frq lfw zlwk wkh prgho iru gdlo| uhwxuqv1 Wkh deryh h{suhvvlrq iru wkh dxwrfryduldqfh ixqfwlrq ri wkh DUPD sur0 fhvv fdq eh xvhg wr fkhfn wkh frqvlvwhqf| ri wkh prgho zlwk wkh surshuwlhv ri wkh gdwd e| frpsdulqj wkh whpsrudo djjuhjdwlrq lpsolhg ghfd| ri wkh dxwrfrydul0 dqfh eldv whup zlwk wkh hpslulfdoo| revhuyhg rqh1 Wr wklv hqg ydulrxv DUPD prghov duh hvwlpdwhg xvlqj wkh plqxwh e| plqxwh uhwxuqv dqg lw lv irxqg wkdw dq DUPD+9/3, prgho |lhogv vdwlvidfwru| uhvxowv8 zlwk xqfruuhodwhg uhvlgxdov dqg uhodwlyho| vwdeoh frh!flhqwv ryhu wlph1 Xvlqj vroho| rqh vhw ri DUPD+9/3, sd0 udphwhuv iru wkh plqxwh gdwd/ dxwrfryduldqfhv iru wkh hvwlpdwhg uhwxuq surfhvv dw ydulrxv vdpsolqj iuhtxhqflhv duh lpsolhg xvlqj h{suhvvlrq E21 Lw lv qrwhg wkdw= 5 6  3   3 [ [ [ 7 8 -sc|c -sc|c ' Es   )s c +6, .[ f s. |c. s. s. '  'n. '. Khqfh/ wkh djjuhjdwlrq lpsolhg dxwrfryduldqfh hvwlpdwhv fdq eh xvhg wr fdo0 fxodwh wkh djjuhjdwlrq lpsolhg dxwrfryduldqfh eldv whup dv lq h{suhvvlrq E

(15) 1 Iljxuh 415 lq wkh dsshqgl{ ghprqvwudwhv wkdw wkh hpslulfdo dqg wkhruhwlfdoo| lp0 solhg fxuyhv duh uhpdundeo| forvh1 Wkh lpsolfdwlrqv ri wklv qglqj duh wzrirog1 Iluvw/ lw vkrzv wkdw wkh DUPD prgho lv d jrrg ghvfulswlrq ri wkh uhwxuq gdwd vdpsohg dw glhuhqw iuhtxhqflhv> wkh ghfd| ri wkh +pdunhw 0 plfurvwuxfwxuh 0 lqgxfhg, vhuldo ghshqghqflhv lq kljk iuhtxhqf| uhwxuqv lv frqvlvwhqw zlwk wkh ghfd| ri dq DUPD surfhvv xqghu whpsrudo djjuhjdwlrq1 Vhfrqg/ uho|lqj rq wkh forvh fruuhvsrqghqfh ehwzhhq wkh hpslulfdo dqg wkhruhwlfdoo| lpsolhg dxwrfr0 8. Dowkrxjk wkh uhvlgxdov duh kljko| ohswrnxuwlf dqg khwhurvnhgdvwlf/ dqg khqfh wkh POH lv qrw h!flhqw/ wkh sdudphwhu hvwlpdwhv duh frqvlvwhqw +vhh h1j1 Dphpl|d +4<;8,,1 Pruhryhu/ wkh h!flhqf| orvv vkrxog eh xqlpsruwdqw jlyhq wkh odujh dprxqw ri gdwd1. ;.

(16) yduldqfh eldv idfwru rqh fdq orfdwh wkh rswlpdo iuhtxhqf|/ wkdw lv/ wkh kljkhvw vdpsolqj iuhtxhqf| dydlodeoh iru zklfk wkh dxwrfryduldqfh eldv whup kdv glhg r/ xvlqj vroho| d vlqjoh vhw ri DUPD sdudphwhu hvwlpdwhv1. 515. Vw|ol}hg Idfwv ri Uhdol}hg Yduldqfh. Kljk iuhtxhqf| gdwd kdyh douhdg| ehhq dqdo|}hg h{whqvlyho| e| d qxpehu ri vwxglhv9 1 Wkh uhvxowv uhjduglqj wkh fkdudfwhulvwlfv ri kljk iuhtxhqf| qdqfldo gdwd rewdlqhg vr idu +uhohydqw iru wklv vwxg|, fdq eh vxppdul}hg dv iroorzv1 Iluvw/ wkh xqfrqglwlrqdo glvwulexwlrq ri gdlo| uhwxuqv lv qrw vnhzhg/ exw lw grhv h{klelw h{fhvv nxuwrvlv1 Gdlo| uhwxuqv duh qrw dxwrfruuhodwhg +h{fhsw iru wkh uvw rughu lq vrph fdvhv,1 Vhfrqg/ wkh xqfrqglwlrqdo glvwulexwlrqv ri uhdol}hg ydul0 dqfh +fdofxodwhg dv wkh vxp ri vtxduhg lqwud0gdlo| uhwxuqv vdpsohg dw iuhtxhqflhv ehwzhhq 8 dqg 53 plqxwhv ghshqglqj rq wkh gdwdvhw xvhg, dqg yduldqfh duh glv0 wlqfwo| qrq0qrupdo dqg h{wuhpho| uljkw vnhzhg/ zkhuhdv wkh qdwxudo orjdulwkp ri wkh vwdqgdug ghyldwlrq lv forvh wr Jdxvvldq1 Wklug/ wkh orj ri wkh uhdol}hg yduldqfh glvsod|v d kljk ghjuhh ri +srvlwlyh, dxwrfruuhodwlrq zklfk glhv rxw yhu| vorzo|1 Irxuwk/ uhdol}hg yduldqfh grhv qrw vhhp wr kdyh d xqlw urrw/ exw wkhuh lv fohdu hylghqfh ri iudfwlrqdo lqwhjudwlrq: / urxjko| ri rughu 31731 Iliwk; / gdlo| uhwxuqv vwdqgdugl}hg e| wkh uhdol}hg yduldqfh phdvxuh duh +qhduo|, Jdxvvldq1 Lq rughu wr frpsohphqw dqg zlghq wkh irfxv ri wkh uhvhdufk lq wklv duhd Hxurshdq vwrfn pdunhw lqgh{ gdwd +plqxwh e| plqxwh gdwd rq wkh IWVH0433 iurp Pd| 4<<3 xqwlo Mdqxdu| 5333, lv xwlol}hg1 Dv phqwlrqhg deryh/ gdlo| uh0 dol}hg yduldqfh rq wkh IWVH0433 lv hvwlpdwhg xvlqj wkh kljk iuhtxhqf| gdwd vdpsohg dw s ' 2D1 Wklv uhvxowv lq d wrwdo ri 5778 uhdol}hg yduldqfh hvwlpdwhv zklfk duh uhsruwhg lq Iljxuh 5141 Lq wkh dsshqgl{/ vrph ghvfulswlyh vwdwlvwlfv ri uhdol}hg yduldqfh/ wkh orj ri uhdol}hg yduldqfh/ wkh gdlo| uhwxuq/ dqg gdlo| uhwxuq vwdqgdugl}hg e| uhdol}hg yduldqfh duh uhsruwhg lq Wdeoh LL1 Wkh vw|ol}hg idfwv duh hvvhqwldoo| frquphg iru wkh gdwdvhw xqghu vwxg|1 Pruh vshflfdoo|/ wkh glvwulexwlrq ri gdlo| uhwxuqv kdv idw wdlov exw lv qrw yhu| vnhzhg dqg ydul0 dqfh foxvwhulqj lv fohduo| suhvhqw lq wkh uhwxuq vhulhv +qrw uhsruwhg,1 Wkh vwurqj 9. Vhh h1j1 Dqghuvrq/ Eroohuvohy/ Glherog dqg Ode|v +5333d/e,/ Iurrw ) Shurog +4<<8,/ Jrrgkduw ) R*Kdud +4<<:,/ Kvlhk +4<<4,/ Ohtxhx{ +4<<<,/ Vwroo ) Zkdoh| +4<<3,/ ]krx +4<<9,1 : Vhh h1j1 Edloolh +4<<9,/ Eroohuvohy dqg Plnnhovhq +4<<9,/ Euhlgw hw1 do1 +4<<;,/ Olx +5333,/ Or +4<<4,1 ; Lq d pxowlyduldwh vhwwlqj lw lv irxqg wkdw wkh glvwulexwlrq ri fruuhodwlrqv ehwzhhq uhdol}hg yduldqfh lv forvh wr qrupdo zlwk srvlwlyh phdq/ dqg wkdw wkh dxwrfruuhodwlrqv ri uhdol}hg fruuhodwlrq ghfd|v h{wuhpho| vorz1. <.

(17) hylghqfh irxqg uhjduglqj wkh qrupdolw| ri wkh gdlo| uhwxuqv vwdqgdugl}hg e| uhdol}hg yduldqfh lqglfdwhv wkdw vlplodu uhvxowv ri Dqghuvhq hw1 do1 +5333e, rq h{fkdqjh udwh gdwd fdq eh h{whqghg wr vwrfn pdunhw lqgh{ gdwd1 Wkh xqfrqgl0 wlrqdo glvwulexwlrq ri wkh uhdol}hg yduldqfh lv vljqlfdqwo| vnhzhg dqg h{klelwv vhyhuh nxuwrvlv/ zkloh wkh xqfrqglwlrqdo glvwulexwlrq ri orj uhdol}hg yduldqfh lv pxfk ohvv vnhzhg dqg glvsod|v vljqlfdqwo| uhgxfhg nxuwrvlv1 Ixuwkhupruh/ wkh fruuhorjudp iru wkh uhdol}hg yduldqfh phdvxuh ghfd|v rqo| yhu| vorzo| exw wkh Dxjphqwhg Glfnh| Ixoohu whvw< vwurqjo| uhmhfwv wkh qxoo k|srwkhvlv ri d xqlw urrw +Wdeoh LL/ Iljxuh 516,1 Wklv odvw revhuydwlrq lv xvxdoo| lqglfdwlyh iru iudfwlrqdo lqwhjudwlrq1. 6. Prghoolqj Uhdol}hg Yduldqfh. Kdylqj fdofxodwhg dqg dqdo|}hg wkh uhdol}hg yduldqfh phdvxuh/ wkh irfxv lv rq qglqj d vwdwlvwlfdo prgho wkdw fdswxuhv wkh pdlq fkdudfwhulvwlfv ri wklv wlph vhulhv1 Vrph revhuydwlrqv iurp wkh suhylrxv vhfwlrq kdyh wr eh wdnhq lqwr df0 frxqw zkhq ghflglqj rq wkh prghoolqj vwudwhj|1 Iluvw ri doo/ wkh ehqhwv ri wkh orj wudqvirupdwlrq ri uhdol}hg yduldqfh lqglfdwh wkdw orj uhdol}hg yduldqfh vkrxog eh prghoohg lqvwhdg ri wkh ruljlqdo vhulhv1 Vhfrqg/ wkh devhqfh ri d xqlw urrw dqg wkh kljko| shuvlvwhqw dxwrfruuhodwlrq srlqw lqwr wkh gluhfwlrq ri iudfwlrqdo lqwhjudwlrq +vhh dsshqgl{ iru d vxppdu| rq wkh frqfhsw ri iudfwlrqdo lqwhjud0 wlrq,1 Wklv vhfwlrq ixuwkhu h{soruhv wkh fkdudfwhulvwlfv ri wkh gdwd dqg qgv wkdw wkh orj ri uhdol}hg yduldqfh vhulhv fdq eh prghoohg zhoo xvlqj d iudfwlrq0 doo| lqwhjudwhg DUPD prgho1 E| phdqv ri dq dssolfdwlrq/ wkh h{lvwhqfh ri wkh Eodfn ohyhudjh hhfw lv whvwhg iru zlwklq wkh DUILPD iudphzrun1 Wkh suhvhqw vhfwlrq frqfoxghv zlwk d glvfxvvlrq ri wkh lpsdfw wkdw vwuxfwxudo euhdnv kdyh rq wkh hpslulfdo qglqjv1. 614. Iudfwlrqdo Lqwhjudwlrq ) Uhdol}hg Yduldqfh. Gulyhq e| wkh uhpdundeoh uhvhpeodqfh ehwzhhq wkh fruuhorjudp glvsod|hg lq Iljxuh 516 lq wkh dsshqgl{ dqg wkh wkhruhwlfdoo| lpsolhg fruuhorjudp iru iudf0 wlrqdoo| lqwhjudwhg surfhvv/ wkh irfxv lv rq iudfwlrqdoo| lqwhjudwhg prghov1 Sulru wr hvwlpdwlrq/ vrph lqirupdo whvwv duh shuiruphg wr vwuhqjwkhq wklv prwlydwlrq1. S Dxjphqwhg Glfnh| Ixoohu whvw= 7{w @  . {w4 . ql@4  l 7{wl . %w 1 Uhmhfwlrq ri K3 =  @ 3/ lpsolhv wkdw {w lv L+3,= Wkh vshflfdwlrq ri wkh odj ohqjwk/ zklfk zh vhw htxdo wr 8/ dvvxphv wkdw %w lv zklwh qrlvh1 Wkh fulwlfdo ydoxh ri wklv whvw htxdov 051;98 dw 8( frqghqfh ohyho dqg 06176< dw 4(1 <. 43.

(18) Wkh iudfwlrqdo glhuhqfh rshudwru lv dssolhg wr wkh orj ri wkh uhdol}hg ydul0 dqfh vhulhv iru ydulrxv ydoxhv ri _ +wkh vhtxhqfh jlyhq e| h{suhvvlrq +8, lq wkh dsshqgl{ lv wuxqfdwhg dw  ' fff,1 Lw lv irxqg wkdw dxwrfruuhodwlrqv duh gudv0 wlfdoo| uhgxfhg iru ydoxhv ri _ ehwzhhq f2D dqg feD dqg wkdw wkh| idoo qlfho| lq ehwzhhq wkh <8( frqghqfh erxqgv + 2 3*2 zkhuh  ghqrwhv wkh qxpehu ri revhuydwlrqv,1 Iru lqvwdqfh/ vhh Iljxuh 517 lq wkh dsshqgl{ zkhuh _ lv vhw htxdo wr fef1 Pruhryhu/ wkh orqj *zdyhv* lq orj uhdol}hg yduldqfh glvdsshdu doprvw hqwluho| diwhu iudfwlrqdo glhuhqflqj +Iljxuh 514 yhuvxv 515,1 D vxssohphqwdu| whvw frqvlvwv ri sorwwlqj orj dxwrfruuhodwlrqv yhuvxv wkh orj ri glvsodfhphqwv1 Lw lv nqrzq wkdw iru d iudfwlrqdoo| lqwhjudwhg surfhvv wkh dxwrfruuhodwlrq ixqfwlrq ghfd|v dw d k|shuerolf udwh dv rssrvhg wr wkh dxwrfruuhodwlrq ixqfwlrq ri dq UEf surfhvv zklfk ghfd|v dw dq h{srqhqwldo udwh1 Wkhuhiruh wkh orj ri wkh dxwr0 fruuhodwlrq ixqfwlrq zloo |lhog d olqhdu uhodwlrqvkls lq whupv ri orj glvsodfhphqw/ l1h1 *L} ) 2 E2_   *L} 1 Iljxuh 518 lq wkh dsshqgl{ vkrzv wkdw sorwwlqj *L} ) djdlqvw *L}  |lhogv d olqhdu uhodwlrqvkls xs wr dssur{lpdwho|  ' ff1 Dq ROV uhjuhvvlrq lv shuiruphg wr ghwhuplqh wkh vorsh1 Xvlqj wkh frpsohwh vdpsoh + ' 2Df, lpsolhv wkdw _  f

(19) .1 Ljqrulqj wkh odvw Df dxwrfruuhodwlrqv lpsolhv wkdw _  fe

(20) 1 Dowkrxjk wkh judsk grhv qrw vwurqjo| lqglfdwh d olqhdu uhodwlrqvkls/ wkh uhvxowv duh qrw wdnhq dv d uhmhfwlrq ri iudfwlrqdo lqwhjudwlrq1 Wkh qdo fkhfn rq wkh suhvhqfh dqg ghjuhh ri iudfwlrqdo lqwhjudwlrq lv grqh lq wkh iuhtxhqf| grpdlq1 Wzr vwdqgdug whvwv duh hpsor|hg1 Wkh uvw rqh kdv ehhq ghyhorshg e| Jhzhnh dqg Sruwhu0Kxgdn +4<;6/ JSK khuhdiwhu,/ zkloh wkh vhfrqg rqh e| Urelqvrq +4<<8,1 D vkruw vxppdu| ri erwk wkh hvwlpdwruv fdq eh irxqg lq wkh dsshqgl{1 Wr lpsohphqw erwk phwkrgv d edqgzlgwk sdudphwhu 6/ frqwuroolqj wkh udqjh ri shulrglf iuhtxhqflhv xvhg/ kdv wr eh vhw1 Dowkrxjk lw lv uhtxluhg wkdw 6 jurz dw d vorzhu udwh wkdq wkh vdpsoh vl}h A / wklv grhv qrw jxlgh xv dv wr zkdw wkh ydoxh ri 6 vkrxog eh1 Lq wkh suhvhqw vwxg|/ _ lv hvwlpdwhg iru d udqjh ri 6 ehwzhhq43 2D dqg 2.D1 Wkh uhvxowv ri wklv hvwl0 pdwlrq duh vxppdul}hg lq Iljxuh 519 zkhuh wkh JSK hvwlpdwhv wrjhwkhu zlwk wkh Urelqvrq hvwlpdwhv duh sorwwhg dv d ixqfwlrq ri 61 Iru vpdoo 6/ wkh wzr dowhuqdwlyh hvwlpdwhv erwk idoo lqwr wkh qrq0vwdwlrqdu| uhjlrq zkloh iru odujh 6 +deryh Df, wkh| duh erwk ehorz 3181 Dowkrxjk lw lv fohdu iurp wklv wkdw wkh ydoxh iru _ zloo eh forvh wr fD/ lw lv gl!fxow wr mxgjh rq wkh vwdwlrqdulw| ri wkh surfhvv dv wkh fkrlfh ri 6 lv uhodwlyho| duelwudu|1 Lq vxppdu|/ wkh uhsruwhg whvw uhvxowv surylgh jrrg uhdvrqv wr eholhyh wkdw wkh +orj, uhdol}hg yduldqfh vhulhv lv iudfwlrqdoo| lqwhjudwhg1 Wkh uhvxowv duh dpeljxrxv dv wr zkdw wkh ydoxh iru _ Wkh vdpsoh vl}h lv 5778 dqg khqfh wkh udqjh ri p lv ehwzhhq W 3=73 dqg W 3=:3 1 Wklv lv lq olqh zlwk h1j1 Eroohuvohy/ Fdl dqg Vrqj +5333, zkr vhwv p @ W 3=83 ru Glwwpdqq dqg Judqjhu +5333, zkr vhw p @ W 3=; 1 43. 44.

(21) zloo eh/ dowkrxjk lw vhhpv fohdu wkdw lw zloo prvw olnho| eh forvh wr fDf1. 615. Hpslulfdo Uhvxowv. Prwlydwhg e| wkh suholplqdu| whvwv glvfxvvhg deryh/ wkh irfxv ri wkh prghoolqj dssurdfk zloo fhqwhu durxqg wkh DUILPD vshflfdwlrq1 Frqvlghu wkh iroorzlqj prgho=   h22Dc|  Z f| ' qEu0| c kEuE  u_ *? j . zkhuh j h22Dc| ghqrwhv wkh gd|| uhdol}hg yduldqfh phdvxuh fdofxodwhg xvlqj 58 plqxwh lqwud0gdlo| uhwxuqv/ f| lv d yhfwru ri h{rjhqrxv yduldeohv/ kEu lv d odj sro|qrpldo ri rughu R/ qEu d odj sro|qrpldo ri rughu ^ dqg 0| lv d uhvlgxdo whup1 Xqghu wkh dvvxpswlrqv wkdw wkh urrwv ri kEu dqg qEu duh rxwvlgh wkh xqlw flu0 foh/ urrwv ri kEu duh vlpsoh/ uhvlgxdov duh llg Qrupdo dqg _ 2 / wkh DUILPD prgho sdudphwhuv duh hvwlpdwhg lq R{44 xvlqj wkh pd{lpxp olnholkrrg hvwl0 pdwru ri Vrzhoo +4<<5,1 Wkh prgho frxog dowhuqdwlyho| eh hvwlpdwhg zlwk wkh srsxodu dqg hdvlo| lpsohphqwdeoh wzr0vwhs surfhgxuh lq zklfk wkh iudfwlrqdo sdudphwhu lv hvwlpdwhg lq wkh uvw vwhs +e| h1j1 wkh JSK ru Urelqvrq hvwlpd0 wru,/ zkloh wkh uhpdlqlqj DUPD frh!flhqwv duh hvwlpdwhg lq wkh vhfrqg vwhs rq wkh iudfwlrqdoo| glhuhqfhg gdwd e| ruglqdu| ohdvw vtxduhv1 Dv lw kdv ehhq irxqg wkdw wkh DUPD frh!flhqwv duh jhqhudoo| hvwlpdwhg lqdffxudwh ru eldvhg wklv zd| +vhh h1j1 Vplwk hw do1 +4<<:,,/ wkh Vrzhoo surfhgxuh lv suhihuuhg dv lw doorzv iru wkh vlpxowdqhrxv hvwlpdwlrq ri wkh prgho sdudphwhuv1 Lq rughu wr dgguhvv wkh frqfhuq wkdw wkh orqj phpru| pd| eh lqgxfhg e| lqiuhtxhqw vwuxfwxudo euhdnv45 +vhh h1j1 Judqjhu +4<<<,/ Glherog dqg Lqrxh +4<<<, dqg Judqjhu dqg K|xqj +4<<<,, wkh deryh prgho lv hvwlpdwhg rq ydulrxv vxevdpsohv1 Wdeoh 6 lq wkh dsshqgl{/ uhsruwv wkh hvwlpdwlrq uhvxowv iru wkh DUILPD prgho +zkhuh R ' ^ ' , iru wzr glhuhqw vdpsohv/ qdpho| Vdpsoh L zklfk uxqv iurp Pd| 4/ 4<<3 xqwlo Mxqh 48/ 4<<: +Hff revhuydwlrqv, dqg Vdpsoh LL zklfk lv wkh ixoo vdpsoh +2eee revhuydwlrqv,1 Dv wkh iudfwlrqdo sdudphwhu uhpdlqv kljko| vljqlfdqw iru wkh glhuhqw vxevdpsohv frqvlghuhg/ lw lv dujxhg wkdw wkh uhdol}hg yduldqfh vhulhv fohduo| h{klelw d orqj phpru| ihdwxuh wkdw lv 44. Vhh Grruqln dqg Rrpv +4<<;, iru grfxphqwdwlrq rq wkh Dupd sdfndjh1 D vlpsoh dqg uhsuhvhqwdwlyh prgho wkdw fdq fdxvh orqj phpru| lv wkh vwrfkdvwlf euhdn prgho zklfk wdnhv wkh iroorzlqj irup= |w @ xw .%w > zkhuh xw @ xw4 .tw4 w > %w  llg Q +3>  5| ,/  w  llg Q +3>  5x , dqg tw htxdov 3 zlwk suredelolw| s dqg 4 zlwk suredelolw| 4  s1 Glherog dqg Lqrxh +4<<<, qrwh wkdw lq rughu wr dfklhyh d vorzo| ghfolqlqj dxwrfruuhodwlrq ixqfwlrq/ zkdwhyhu wkh prgho pd| eh/ wkh nh| lghd lv wr ohw s ghfuhdvh zlwk wkh vdpsoh vl}h vr wkdw uhjdugohvv ri wkh vdpsoh vl}h/ uhdol}dwlrqv ri wkh surfhvv whqg wr kdyh mxvw d ihz euhdnv1 45. 45.

(22) qrw fdxvhg e| vwuxfwxudo euhdnv1 Iru erwk vdpsohv/ wkh iudfwlrqdo sdudphwhu _ lv lqghhg ehwzhhq fef dqg fDf/ frquplqj wkh suholplqdu| dqdo|vlv deryh1 Lq idfw/ edvhg rq wkh |vwdwlvwlf rqh fdqqrw uhmhfw wkdw _ : fD dw d bDI frqghqfh ohyho= wkh uhdol}hg yduldqfh vhulhv pd| eh qrq0vwdwlrqdu|1 Uhjduglqj wkh lqfoxvlrq ri h{rjhqrxv yduldeohv46 / odjjhg uhwxuqv dqg frqwhpsrudqhrxv wudglqj yroxph duh frqvlghuhg1 Wklv fkrlfh ri yduldeohv lv prwlydwhg e| Eodfn +4<:9, dqg Odprxuhx{ dqg Odvwudshv +4<<3d, uhvshfwlyho|1 Eodfn*v ohyhudjh vwdwhv wkdw qhjdwlyh uhwxuqv kdyh d odujhu lpsdfw rq ixwxuh yduldqfh wkdq gr srvlwlyh uhwxuqv1 Rqh srvvleoh udwlrqdoh iru wklv lv wkdw zkhq htxlw| ydoxh ghfuhdvhv wkh ghew0wr0htxlw| udwlr lqfuhdvhv/ wkhuhe| udlvlqj wkh ulvnlqhvv ri wkh up dv pdqlihvwhg e| dq lqfuhdvh lq ixwxuh yduldqfh1 Prgli|lqj wkh deryh prgho dv iroorzv=. 3 3 n n 3 3 n Z f| ' l n  -|3 n l  -|3 n  n l 6 -|36 n l 6 -|36 c . zkhuh -n +-3 , lv d yhfwru frqwdlqlqj wkh srvlwlyh +qhjdwlyh, gdlo| uhwxuqv dqg }hur rwkhuzlvh/ doorzv dq dvvhvvphqw ri wkh h{sodqdwru| srzhu ri odjjhg uhwxuqv zkloh wkh uhodwlyh pdjqlwxgh ri wkh l frh!flhqwv zloo lqglfdwh zkhwkhu d ohyhudjh hhfw lv suhvhqw1 Iurp wkh hvwlpdwlrq uhvxowv uhsruwhg lq wkh dsshqgl{ +Wdeoh LLL, lw fdq eh revhuyhg wkdw wkh orj olnholkrrg ydoxh gudvwlfdoo| lqfuhdvhv zkhq odjjhg uhwxuqv duh dgghg dqg wkdw wkh DLF lqirupdwlrq fulwhuld gursv iurp derxw 31; wr 3181 Pruhryhu/ frh!flhqwv rq qhjdwlyh uhwxuqv duh frqvlvwhqwo| deryh frh!flhqwv rq srvlwlyh uhwxuqv1 Dowkrxjk wklv revhuydwlrq lv lqglfdwlyh iru wkh suhvhqfh ri wkh ohyhudjh hhfw/ lwv vljqlfdqfh lv whvwhg iru e| uhirupxodwlqj wkh prgho dv iroorzv= l  -|3 n l  m-|3 m n  n l  -|3 n l  m-|3 m . 3 3  n Qrwh wkdw l  ' 2 El n   l   dqg l  ' 2 El  n l  1 Zkhuh l  lv vljqlfdqwo| qhjdwlyh47 / lw fdq eh frqfoxghg wkdw wkh ohyhudjh hhfw lv vljqlfdqw dw krul}rq 1 Hvwlpdwlrq uhvxowv48 lqglfdwh wkdw wkh ohyhudjh hhfw/ dv sursrvhg e| Eodfn 46. Jorvwhq/ Mdjdqqdwkdq dqg Uxqnoh +4<<6, qg wkdw wkh vkruw whup lqwhuhvw udwh kdv d vljqlfdqw srvlwlyh hhfw rq vwrfn pdunhw yrodwlolw|1 Wkh 4 prqwk XN Lqwhuedqn udwh lv dgghg/ exw iru wkh gdwdvhw xqghu vwxg| lw grhv qrw dsshdu wr eh d vljqlfdqw uhjuhvvru1 Wkh gdwd iuhtxhqf| +gdlo|, lq wkh suhvhqw dqdo|vlv pd| zhoo eh wrr kljk iru wkh lqwhuhvw udwh wr kdyh d vljqlfdqw lq xhqfh1  47 Qrwh wkdw u @ u.  u dqg mum @ u. . u 1 Wkhuhiruh/  . l @  l .  l dqg  l @  l   l = Iru  . ohyhudjh wr eh suhvhqw lw lv uhtxluhg wkdw  l   l @ 5   l A 3 ru  l ? 31 48 Wkh hvwlpdwhv iru  4 >  5 dqg  6 duh 7=93 +7=54,/ 8=8; +8=46, dqg 6=;4 +6=7<, uhvshf0 wlyho|1 w0ydoxhv duh lq sduhqwkhvlv1. 46.

(23) +4<:9,/ lv suhvhqw dw wkh uvw wkuhh krul}rqv dqg lv lqvljqlfdqw diwhuzdugv1 Qrwh wkdw dowkrxjk wkh vwdwlvwlfdo vljqlfdqfh ri wklv qglqj grhv qrw qhfhvvdulo| lpso| dq hfrqrplf vljqlfdqfh/ lw grhv surylgh vxssruw iru wkh JMU0JDUFK dqg HJDUFK vshflfdwlrqv zklfk h{solflwo| dffrxqw iru wkh dv|pphwulf hhfw wkdw uhwxuqv kdyh rq ixwxuh yduldqfh1 Wkh lqfoxvlrq ri +orj, frqwhpsrudqhrxv wudglqj yroxph kdv ehhq vxj0 jhvwhg e| Odprxuhx{ dqg Odvwudshv +4<<3d,1 Wkh| glvfxvv d prgho lq zklfk khwhurvnhgdvwlflw| uhvxowv iurp wlph ghshqghqfh lq wkh surfhvv zklfk jryhuqv wkh lqirupdwlrq rz wr wkh pdunhw1 Wdnlqj wudglqj yroxph dv d sur{| iru wkh lqirupdwlrq duulydo udwh wkh| dujxh +dqg vkrz hpslulfdoo|, wkdw +l, wudglqj yroxph lv srvlwlyho| uhodwhg wr uhwxuq yduldqfh dqg +ll, wkh shuvlvwhqfh ri uh0 wxuq yduldqfh ghfuhdvhv +ru glvdsshduv, zkhq wudglqj yroxph lv dffrxqwhg iru1 Edvhg rq wkh hvwlpdwlrq uhvxowv uhsruwhg lq wkh dsshqgl{/ zkhuh bf ghqrwhv wkh uhjuhvvlrq frh!flhqw ri orj frqwhpsrudqhrxv wudglqj yroxph/ lw lv irxqg wkdw wudglqj yroxph ixuwkhu lpsuryhv wkh w ri wkh prgho dqg/ frqvlvwhqw zlwk wkh wkhru|/ kdv d vljqlfdqw srvlwlyh hhfw rq yduldqfh1 Wkh iudfwlrqdo sdudphwhu _ grhv/ krzhyhu/ qrw ghfuhdvh xsrq lqfoxvlrq ri wudglqj yroxph lqglfdwlqj wkdw wkh shuvlvwhqfh ri wkh yduldqfh surfhvv uhpdlqv xqfkdqjhg xsrq frqglwlrqlqj rq wudglqj yroxph1. 7. Iruhfdvwlqj Uhdol}hg Yduldqfh. Xowlpdwho| wkh jrdo ri dqdo|}lqj dqg prghoolqj yduldqfh lv wr xvh wkh uhvxowlqj prgho iru uhwxuq yduldqfh iruhfdvwlqj1 Reylrxvo|/ wklv lv ri juhdw lqwhuhvw wr wkh hogv ri ulvn pdqdjhphqw dqg ghulydwlyh sulflqj1 Wklv vhfwlrq dvvhvvhv wkh iruh0 fdvwlqj delolw| ri wkh DUILPD prgho iru gdlo| orj +uhdol}hg, yduldqfh dqg wdnhv d vwdqgdug JDUFK+4/4, prgho/ lpsohphqwhg zlwk gdlo| uhwxuqv/ dv d ehqfk0 pdun1 Dv wkh gdwdvhw lq wklv vwxg| grhv qrw doorz xv wr vwxg| wkh iruhfdvwlqj shuirupdqfh ri wkh prghov lq ghswk/ d vlpxodwlrq vwxg| lv xqghuwdnhq1. 714. Vlpxodwlrq Ghvljq. Wkh dssurdfk wdnhq lv dv iroorzv1 Lq hyhu| vlpxodwlrq uxq d wlph vhulhv ri 2.Df gdlo| orj +uhdol}hg, uhwxuq yduldqfhv lv jhqhudwhg dffruglqj wr dq DUILPD+3/g/3, surfhvv=   E  u_ *? j 2|  > ' 0| c 47.

(24) zkhuh 0| l1l1g1Q Efc 720 1 Wkh udwlrqdoh iru h{foxglqj wkh dxwruhjuhvvlyh dqg prylqj dyhudjh whupv/ zklfk jryhuq wkh vkruw uxq g|qdplfv ri wkh surfhvv/ lv wkdw lqfoxglqj ru h{foxglqj wkhp lv xqolnho| wr fkdqjh wkh uhvxowv txdolwd0 wlyho|1 Prwlydwhg e| wkh hpslulfdo uhvxowv ri wkh odvw vhfwlrq wkh phdq > ' f/ wkh iudfwlrqdo sdudphwhu _ ' feD dqg wkh uhvlgxdo yduldqfh 720 ' fD1 Wr   rewdlq iruhfdvwv ri *? j 2 / qrwh wkdw .A 3 E  u_ E*? j2A  > ' f ru htxlyd0   S KE3_ 2 ohqwo| .A 3 d*? j 2A  >o '  " ' KEnKE3_ *? j A 3  > 1 Wklv dxwruhjuhvvlyh uhsuhvhqwdwlrq ri *? j2A fdq eh xvhg wr uhfxuvlyho| frpsxwh wkh rvwhs dkhdg iruhfdvwv +zkhuh wkh lqqlwh DU sro|qrpldo lv wuxqfdwhg dw  ' 2Dff odjv iru sudfwlfdo lpsohphqwdwlrq,1 Wkh rvwhs dkhdg iruhfdvw ri orj uhdol}hg yduldqfh   zloo kdyh d iruhfdvw huuru "|cr ' .| *? j 2|nr *? j 2|nr / wkdw lv qrupdoo| glvwulexwhg zlwk phdq f dqg yduldqfh 72r 1 Dv d frqvhtxhqfh wkh iruhfdvw huuru iru uhdol}hg   yduldqfh49 / "|cr ' .| i TE*? j2|nr   j 2|nr / zloo kdyh d orj qrupdo glvwulexwlrq   zlwk d phdq htxdo wr i T 2 72r 1 Jlyhq wkdw wkh irfxv lv rq wkh uhdol}hg ydul0 dqfh iruhfdvwv +dqg qrw wkh orj ri lw,/ wklv eldv lv fruuhfwhg iru e| xvlqj dq hvwlpdwh ri 72r 1 Lq hyhu| vlpxodwlrq uxq wkh iudfwlrqdo sdudphwhu ri wkh DUILPD prgho lv hvwlpdwhg xvlqj wkh JSK hvwlpdwru1 D ghqvlw| ri wkh hvwlpdwhv lv jlyhq lq Iljxuh 6171 Wr dvvhvv wkh iruhfdvwlqj shuirupdqfh ri wkh DUILPD prgho iru uhdol}hg yduldqfh wkh JDUFK+4/4, prgho/ prwlydwhg e| lwv zlghvsuhdg xvdjh lq yduldqfh prghoolqj dqg iruhfdvwlqj/ lv wdnhq dv d ehqfkpdun1 Gdlo| uhwxuq gdwd/ zklfk duh qhhghg iru wkh lpsohphqwdwlrq ri wkh JDUFK prgho/ duh frqvwuxfwhg e| pxowlso|lqj wkh vlpxodwhg uhdol}hg yduldqfh vhulhv zlwk dq llg vwdqgdug qrupdo udqgrp yduldeoh1 Wr dyrlg uh0hvwlpdwlrq ri wkh JDUFK sdudphwhuv dw hyhu| vlpxodwlrq uxq k dqg q  duh {hg zkloh wkh lqwhufhsw/ // lv vhw vxfk wkdw wkh xqfrqglwlrqdo phdq ri wkh JDUFK surfhvv/ 3k/ 3q / htxdov wkh hvwlpdwhg  xqfrqglwlrqdo yduldqfh ri wkh uhwxuq surfhvv1 Uhjduglqj wkh fkrlfh ri k dqg q  / wzr fdvhv duh frqvlghuhg1 Lq wkh uvw prgho vshflfdwlrq/ zklfk lv uhihuuhg wr dv JDUFK4/ k ' fbf dqg q  ' ffD1 Lq wkh JDUFK5 vshflfdwlrq wkh shuvlvwhqfh ri wkh yduldqfh surfhvv lv lqfuhdvhg e| lqfuhdvlqj k wr fbe zkloh ohdylqj q  xqfkdqjhg1 Wkh rvwhs dkhdg iruhfdvw ri gdlo| uhdol}hg yduldqfh /E3Eknq r3  e2A nrƒA ' n jhqhudwhg e| wkh JDUFK prgho/ j e2A nƒA / lv jlyhq e| j 3k3q r3 2 Ek n q j eA nƒA 1 Qrwh wkdw wkh orqj uxq iruhfdvw whqgv wr wkh xqfrqglwlrqdo phdq ri wkh yduldqfh surfhvv h{srqhqwldoo| idvw1 Ilqdoo|/ wkh lqirupdwlrq vhw iru 49. Qrwh wkdw wkh vlpxodwhg uhdol}hg yduldqfh vhulhv zloo eh orj qrupdo dqg kdyh dq xqfrqgl0 k l5   S +kg, wlrqdo phdq htxdo wr h{s  . 45 f75% zkhuh f @ 4 k@3 +k.4,+g, 1 Iru g @ 3=78 zh kdyh f  5=8 +zh fxw ri wkh lqqlwh vxppdwlrq dw k @ 5833, zklfk fruuhvsrqgv wr dq dqqxdo uhwxuq yrodwlolw| ri derxw 48(1. 48.

(25) iruhfdvwlqj frqvlvwv ri wkh uvw 2Dff revhuydwlrqv zkloh wkh iruhfdvwlqj krul}rq/ r/ wdnhv rq ydoxhv ehwzhhq  dqg 2Df +rqh gd| xs wr rqh |hdu,1 Wkh vlpxodwlrq lv uhshdwhg & ' Dfff wlphv1. 715. Shuirupdqfh Phdvxuhphqw dqg Vlpxodwlrq Uhvxowv. e rc A ' Sr j Iru qrwdwlrqdo frqyhqlhqfh ohw P e2A nc A > wkh iruhfdvwhg fxpxod0  ' wlyh uhdol}hg yduldqfh ryhu d vshflhg iruhfdvw krul}rq r vwduwlqj dw shulrg A 1 Wkh vxevfulsw  ' c    c & ghqrwhv wkh vlpxodwlrq uxq1 Dqdorjrxvo|/ ghqh Sr j 2A nc dv wkh fxpxodwlyh wuxh yduldqfh ryhu d vshflhg iruh0 Prc A '  ' fdvw krul}rq r vwduwlqj dw shulrg A 1 Wkh iruhfdvwlqj shuirupdqfh ri hdfk prgho lv phdvxuhg e| frpsxwlqj wkh vxp ri vtxduhg huuru fulwhuld= 77.Er ' u l2 S& k e 2 2 Prc A  Prc A 1 Wr phdvxuh srwhqwldo frqvlvwhqw ryhu ru xqghu hvwlpd0 ' ƒ. ƒ. ƒ. ƒ. ƒ. wlrq wkh udwlr ri iruhfdvwhg dqg dfwxdo dyhudjh uhdol}hg yduldqfh duh frpsxwhg S e 2 * S& P2  iru wkh glhuhqw iruhfdvwlqj krul}rqv= -8 Er ' &' P ' rc A rc A ƒ. ƒ. Wkh vlpxodwlrq uhvxowv duh uhsruwhg lq wkh dsshqgl{1 Iljxuh

(26)  ghprq0 vwudwhv wkdw wkh iruhfdvwv iru doo prghov dqg doo krul}rqv duh yluwxdoo| xqeldvhg1 Iru iruhfdvwv xs wr d |hdu wkh pd{lpxp xqghu ru ryhu hvwlpdwlrq ri wkh dffx0 pxodwhg uhdol}hg yduldqfh lv derxw 518( ri wkh dfwxdo ydoxh1 Wkh vxp ri vtxduhg huuru fulwhuld/ zklfk lv xvhg wr dvvhvv wkh prghov* iruhfdvwlqj shuirupdqfh/ lv sorwwhg lq Iljxuh

(27) 21 Qrw vxusulvlqjo|/ lw lv irxqg wkdw wkh DUILPD prgho grhv wkh ehvw mre iru doo krul}rqv frqvlghuhg1 Krzhyhu/ wkh glhuhqfh lq 77. ehwzhhq wkh DUILPD dqg JDUFK prgho iru iruhfdvwlqj krul}rqv xs wr vd| 6 prqwkv lv vpdoo1 Iru orqjhu iruhfdvwlqj krul}rqv wkh DUILPD fohduo| rxwshuirupv wkh JDUFK1 Wklv fdq eh dwwulexwhg wr wkh DUILPD prgho*v delolw| wr dffrxqw iru wkh orqj phpru| surshuw| ri wkh orj uhdol}hg yduldqfh vhulhv1 Wkh vwdqgdug gh0 yldwlrqv ri iruhfdvwlqj huuruv duh sorwwhg lq Iljxuh

(28) 

(29) > wkh DUILPD prgho kdv wkh orzhvw iruhfdvw huuru yduldqfh iru doo krul}rqv1 Ilqdoo|/ wkh vwdqgdug ghyld0 wlrq/ vnhzqhvv dqg nxuwrvlv ri wkh iruhfdvw huuruv duh fdofxodwhg +qrw uhsruwhg,1 Wkh uhvxowv lqglfdwh wkdw erwk vnhzqhvv dqg nxuwrvlv duh doprvw lghqwlfdo iru wkh glhuhqw prghov1 Pruhryhu/ wkh| ghfuhdvh zlwk wkh iruhfdvw krul}rq> vnhzqhvv iurp derxw D iru gdlo| krul}rq wr fD iru |hduo| krul}rq1 Nxuwrvlv iurp HD iru gdlo| krul}rq wr derxw eD iru |hduo| krul}rq1 Vrph frpsolphqwdu| vlpxod0 wlrqv duh shuiruphg wr lqyhvwljdwh wkh prgho dqg sdudphwhu hvwlpdwlrq ulvn exw lw lv irxqg wkdw iru erwk wkh DUILPD dqg wkh JDUFK prgho wklv ulvn dsshduv wr eh qhjoljleoh1 Wkh qdlyh dqg vlpsoh hvwlpdwlrq surfhgxuh ri wkh JDUFK |lhogv vhqvleoh iruhfdvwv zkloh wkh DUILPD prgho*v iruhfdvwlqj shuirupdqfh lv 49.

(30) lqvhqvlwlyh wr qrlv| lqsxw ydoxhv ri wkh iudfwlrqdo sdudphwhu1 Wkh uhvxowv uhsruwhg deryh vxjjhvw wkdw wkh DUILPD prgho/ dv h{shfwhg/ rxwshuirupv wkh uhsuhvhqwdwlyh JDUFK prgho dffruglqj wr doo wkh fulwhuld xvhg1 Vhyhudo srlqwv vkrxog/ krzhyhu/ eh qrwhg1 Wkh iruhfdvwv ri wkh DUILPD prgho duh rewdlqhg iurp d wuxqfdwhg lqqlwh dxwruhjuhvvlrq/ jhqhudoo| lqfoxglqj d wkrxvdqg odjv ru pruh1 Lq frqwudvw/ iruhfdvwv ri wkh JDUFK prgho fdq eh frqvwuxfwhg xvlqj vroho| rqh odjjhg uhwxuq dqg frqglwlrqdo yduldqfh hvwlpdwh1 Pruhryhu/ wkh JDUFK prgho fdq eh lpsohphqwhg zlwk gdlo| uhwxuqv zkloh wkh DUILPD prgho uhtxluhv lqwud0gdlo| uhwxuq gdwd iru wkh fdofxodwlrq ri wkh uh0 dol}hg yduldqfh phdvxuh1 Lw lv wkhuhiruh fohdu wkdw wkh DUILPD prgho zloo eh pruh gl!fxow wr lpsohphqw lq sudfwlvh wkdq wkh JDUFK prgho1 Lq dgglwlrq/ iru d jlyhq iruhfdvwlqj krul}rq/ wkh shuvlvwhqfh ri wkh plvvshflhg JDUFK fdq eh frqwuroohg iru e| {lqj wkh sdudphwhuv wr wkh dssursuldwh ydoxhv vr dv wr plq0 lpl}h wkh glhuhqfh lq iruhfdvwlqj shuirupdqfh zlwk uhvshfw wr wkh DUILPD prgho> zkloh iru vkruw krul}rq iruhfdvwlqj wkh h{lelolw| ri wkh JDUFK lv pruh lpsruwdqw wkdq lwv shuvlvwhqfh/ wkh rssrvlwh lv wuxh iru orqj krul}rq iruhfdvwlqj zkhuh d kljk shuvlvwhqfh lv qhhghg wr frxqwhu wkh orqj phpru| surshuw| ri wkh yduldqfh surfhvv +l1h1 JDUFK4 yhuvxv JDUFK5 lq Iljxuh 615 dqg 616,1. 8. Vxppdu|. Plqxwh e| plqxwh gdwd rq wkh IWVH0433 vwrfn pdunhw lqgh{ kdyh ehhq hp0 sor|hg wr fdofxodwh dqg dqdo|}h gdlo| uhdol}hg yduldqfh1 Lw kdv ehhq vkrzq wkdw lq rughu wr lpsohphqw wkh vxp ri vtxduhg uhwxuqv dssurdfk wr fdofxodwh uhdo0 l}hg yduldqfh/ d fduhixo fkhfn rq vhuldo ghshqghqfh lq kljk iuhtxhqf| uhwxuqv lv uhtxluhg vr dv wr dyrlg vhulrxv eldvhv lq wkh uhvxowlqj phdvxuh iru dyhudjh gdlo| uhwxuq yduldqfh> l1h1 iru wkh IWVH0433 gdwd wklv +grzqzdug, eldv dprxqwv xs wr 68( iru wkh plqxwh gdwd1 Lq dgglwlrq/ lw kdv ehhq vkrzq wkdw wkh ghfd| ri vhuldo ghshqghqfh zlwk wkh vdpsolqj iuhtxhqf| lv frqvlvwhqw zlwk dq DUPD prgho xqghu whpsrudo djjuhjdwlrq1 Wklv qglqj fdq eh xvhg wr vhw wkh rs0 wlpdo vdpsolqj iuhtxhqf|/ wkdw lv/ wkh kljkhvw srvvleoh vdpsolqj iuhtxhqf| dw zklfk wkh dxwrfryduldqfh eldv idfwru lv qhjoljleoh1 Prwlydwhg e| vhyhudo whvw vwdwlvwlfv iru wkh suhvhqfh ri orqj phpru|/ wkh uhdol}hg yduldqfh wlph vhulhv lv prghoohg dv dq DUILPD prgho1 Odjjhg uhwxuqv dqg wudglqj yroxph duh irxqg wr eh vljqlfdqw uhjuhvvruv1 Wkh Eodfn ohyhudjh hhfw lv whvwhg iru dqg irxqg wr eh suhvhqw dw krul}rqv ri rqh wr wkuhh gd|v1 Wklv qglqj lv vxssruwlyh iru dv|pphwulf JDUFK prghov vxfk dv wkh HJDUFK dqg JMU JDUFK prgho1 4:.

(31) Frqwhpsrudqhrxv wudglqj yroxph lv khosixo lq h{sodlqlqj wkh yduldwlrq lq uhdo0 l}hg yduldqfh/ dowkrxjk wkh shuvlvwhqfh ri wkh surfhvv uhpdlqv xqfkdqjhg xsrq lqfoxvlrq ri wklv yduldeoh1 Lq d vlpxodwlrq vwxg| wkh iruhfdvwlqj shuirupdqfh ri wkh DUILPD prgho iru gdlo| +uhdol}hg, yduldqfh lv dvvhvvhg dqg lw lv irxqg wkdw lw rxwshuirupv frqyhqwlrqdo JDUFK w|sh prghov1 Lw vkrxog eh qrwhg/ krzhyhu/ wkdw dowkrxjk wkh DUILPD prgho zrunv ehvw/ lwv lpsohphqwdwlrq uh0 txluhv pxfk pruh gdwd wkdq wkh JDUFK1 Wkh uhodwlyho| vpdoo orvv dw vkruw krul}rqv wrjhwkhu zlwk wkh h{lelolw| ri wkh JDUFK wr dffrxqw iru shuvlvwhqfh lq wkh yduldqfh surfhvv/ pdnh lw d uhdvrqdeoh dowhuqdwlyh wr wkh frpsolfdwhg dqg gdwd lqwhqvlyh DUILPD prgho iru uhdol}hg yduldqfh1. 4;.

(32) 9. Uhihuhqfhv. Dphpl|d/ W1 +4<;8,/ Dgydqfhg Hfrqrphwulfv/ Kduydug Xqlyhuvlw| Suhvv/ PD Dqghuvhq/ W1J1 dqg W1 Eroohuvohy +4<<;,/ Dqvzhulqj wkh vnhswlfv= \hv/ vwdqgdug yrodwlolw| prghov gr surylgh dffxudwh iruhfdvwv/ Lqwhuqdwlrqdo Hfr0 qrplf Uhylhz 6</ Qr1 7/ ;;80<38 Dqghuvhq/ W1J1/ W1 Eroohuvohy/ I1[1 Glherog dqg S1 Ode|v +5333d,/ Wkh Glvwulexwlrq ri Uhdol}hg H{fkdqjh Udwh Yrodwlolw|/ iruwkfrplqj Mrxuqdo ri wkh Dphulfdq Vwdwlvwlfdo Dvvrfldwlrq Dqghuvhq/ W1J1/ W1 Eroohuvohy/ I1[1 Glherog dqg S1 Ode|v +5333e,/ H{0 fkdqjh udwh uhwxuqv vwdqgdugl}hg e| uhdol}hg yrodwlolw| duh +qhduo|, Jdxvvldq/ QEHU Zrunlqj Sdshu Qr1 :7;;1 Dqghuvhq/ W1J1/ W1 Eroohuvohy/ I1[1 Glherog dqg K1 Hehqv +5333,/ Wkh Glvwulexwlrq ri Vwrfn Uhwxuq Yrodwlolw|/ Mrxuqdo ri Ilqdqfldo Hfrqrplfv / iruwkfrplqj1 Edloolh/ U1W1 +4<<9,/ Orqj Phpru| Surfhvvhv dqg Iudfwlrqdo Lqwhjudwlrq lq Hfrqrphwulfv/ Mrxuqdo ri Hfrqrphwulfv :6/ 808< Eodfn/ I1 +4<:9,/ Vwxglhv ri vwrfn sulfh yrodwlolw| fkdqjhv/ Surfhhglqj iurp wkh Dphulfdq Vwdwlvwlfdo Dvvrfldwlrq/ Exvlqhvv dqg Hfrqrplf Vwdwlvwlfv Vhfwlrq/ 4::04;4 Eroohuvohy/ W1/ M1 Fdl dqg I1P1 Vrqj +5333,/ Lqwud0gd| Shulrglflw|/ Orqj Phpru| Yrodwlolw| dqg Pdufrhfrqrplf dqqrxqfhphqw hhfwv lq wkh XV Wuhd0 vxu| Erqg Pdunhw/ Mrxuqdo ri Hpslulfdo Ilqdqfh :/ 6:088 Eroohuvohy/ W1 dqg K1R1 Plnnhovhq +4<<9,/ Iudfwlrqdoo| Lqwhjudwhg Jhqhu0 dol}hg Dxwruhjuhvvlyh Frqglwlrqdo Khwhurvnhgdvwlflw|/ Mrxuqdo ri Hfrqrphwulfv :7/ 6063 Euhlgw/ I1M1/ Q1 Fudwr dqg S1 gh Olpd +4<<;,/ Wkh Ghwhfwlrq dqg Hvwl0 pdwlrq ri Orqj Phpru| lq Vwrfkdvwlf Yrodwlolw|/ Mrxuqdo ri Hfrqrphwulfv ;6/ 658067; Glherog/ I1[1 dqg D1 Lqrxh +4<<<,/ Orqj Phpru| dqg Vwuxfwxudo Fkdqjh/ Pdqxvfulsw Glwwpdqq/ L1 dqg F1Z1M1 Judqjhu +5333,/ Surshuwlhv ri Qrqolqhdu Wudqv0 irupdwlrqv ri Iudfwlrqdoo| Lqwhjudwhg Surfhvvhv/ XFVG glvfxvvlrq sdshu 53330 3:1 4<.

(33) Grruqln/ M1D1 dqg P1 Rrpv +4<<;,/ D Sdfndjh iru Hvwlpdwlrq/ Iruhfdvw0 lqj dqg Vlpxodwlqj Dupd Prghov= Dupd sdfndjh 413 iru R{/ plphr Qx!hog Froohjh/ R{irug1 Iuhqfk/ N1U1/ Vfkzhuw/ J1Z1 dqg Vwdpedxjk/ U1I1 +4<;:,/ H{shfwhg Vwrfn Uhwxuqv dqg Yrodwlolw|/ Mrxuqdo ri Ilqdqfldo Hfrqrplfv 4</ 605< Iurrw/ N1D1 dqg D1I1 Shurog +4<<8,/ Qhz Wudglqj Sudfwlfhv dqg Vkruw0 Uxq Pdunhw H!flhqf|/ Mrxuqdo ri Ixwxuhv Pdunhwv 48+:,/ :640:98 Jhzhnh M1 dqg V1 Sruwhu0Kxgdn +4<;6,/ Wkh Hvwlpdwlrq dqg Dssolfdwlrq ri Orqj Phpru| Wlph Vhulhv Prghov/ Mrxuqdo ri Wlph Vhulhv Dqdo|vlv 7+7,/ 554056; Jorvwhq/ Mdjdqqdwkdq dqg Uxqnoh +4<<6,/ Rq wkh uhodwlrq ehwzhhq wkh h{shfwhg ydoxh dqg wkh yrodwlolw| ri wkh qrplqdo h{fhvv uhwxuq rq vwrfnv/ Mrxu0 qdo ri Ilqdqfh 7;/ 4::<04;34 Jrrgkduw/ F1D1H1 dqg P1 R*Kdud +4<<:,/ Kljk Iuhtxhqf| Gdwd lq Il0 qdqfldo Pdunhwv= Lvvxhv dqg Dssolfdwlrqv/ Mrxuqdo ri Hpslulfdo Ilqdqfh 7/ :60447 Judqjhu/ F1Z1M1 +4<;3,/ Orqj phpru| uhodwlrqvklsv dqg wkh djjuhjdwlrq ri g|qdplf prghov/ Mrxuqdo ri Hfrqrphwulfv 47/ 55:056; Judqjhu/ F1Z1M1 +4<;4,/ Vrph surshuwlhv ri wlph vhulhv gdwd dqg wkhlu xvh lq hfrqrphwulf prgho vshflfdwlrq/ Mrxuqdo ri Hfrqrphwulfv 49/ 4540463 Judqjhu/ F1Z1M1 +4<<<,/ Dvshfwv ri Uhvhdufk Vwudwhjlhv iru Wlph Vhulhv Dqdo|vlv/ Rxwolqh ri suhvhqwdwlrq wr wkh frqihuhqfh rq Qhz Ghyhorsphqwv lq Wlph Vhulhv Hfrqrplfv dw wkh Frzohvv Irxqgdwlrq/ Qhz Kdyhq1 Judqjhu/ F1Z1M1 dqg Q1 K|xqj +4<<<,/ Rffdvlrqdo Vwuxfwxudo Euhdnv dqg Orqj Phpru|/ XFVG glvfxvvlrq sdshu <<0471 Judqjhu/ F1Z1M1 dqg U1 Mr|hx{ +4<;3,/ Dq lqwurgxfwlrq wr orqj0phpru| wlph vhulhv dqg iudfwlrqdo glhuhqflqj/ Mrxuqdo ri Wlph Vhulhv Dqdo|vlv/ 4 Kvlhk/ G1D1 +4<<4,/ Fkdrv dqg Qrqolqhdu G|qdplfv= Dssolfdwlrq wr Il0 qdqfldo Pdunhwv/ Mrxuqdo ri Ilqdqfh 79+8,/ 4;6<04;:: Odprxuhx{/ F1J1 dqg Z1G1 Odvwudshv +4<<3,/ Khwhurvnhgdvwlflw| lq Vwrfn Uhwxuq Gdwd= Yroxph yhuvxv JDUFK hhfwv/ Mrxuqdo ri Ilqdqfh 78+4,/ 5540 55< Odprxuhx{/ F1J1 dqg Z1G1 Odvwudshv +4<<3e,/ Shuvlvwhqfh lq Yduldqfh/ Vwuxfwxudo Fkdqjh dqg wkh JDUFK Prgho/ Mrxuqdo ri Exvlqhvv ) Hfrqrplf Vwdwlvwlfv 9+5,/ 5580567 53.

(34) Ohtxhx{/ S1 +4<<<,/ Ilqdqfldo Pdunhwv Wlfn e| Wlfn= Lqvljkwv lq Ilqdqfldo Pdunhw Plfur Vwuxfwxuh/ Mrkq Zloh| ) Vrqv Owg/ Hqjodqg Olx/ P1 +5333,/ Prgholqj Orqj Phpru| lq Vwrfn Pdunhw Yrodwlolw|/ Mrxuqdo ri Hfrqrphwulfv <</ 46<04:4 Or/ D1Z1 +4<<4,/ Orqj Phpru| lq Vwrfn Pdunhw Sulfhv/ Hfrqrphwulfd 8<+8,/ 45:<04646 Pdgkdydq/ D1 +5333,/ Pdunhw Plfurvwuxfwxuh= D Vxuyh|/ Mrxuqdo ri Ilqdqfldo Pdunhwv 6/ 538058; Phuwrq/ U1F1 +4<;3,/ Rq Hvwlpdwlqj wkh H{shfwhg Uhwxuq rq wkh Pdunhw> Dq H{sorudwru| Lqyhvwljdwlrq/ Mrxuqdo ri Ilqdqfldo Hfrqrplfv ;/ 6560694 Qhovrq/ G1E1 +4<<4,/ Frqglwlrqdo Khwhurvnhgdvwlflw| lq dvvhw uhwxuqv= D qhz dssurdfk/ Hfrqrphwulfd 8</ 67:0:3 Urelqvrq/ S1P1 +4<<8d,/ Orj0Shulrgrjudp Uhjuhvvlrq ri Wlph Vhulhv zlwk Orqj Udqjh Ghshqghqfh/ Dqqdov ri Vwdwlvwlfv 56+6,/ 437;043:5 Urelqvrq/ S1P1 +4<<8e,/ Jdxvvldq Vhplsdudphwulf Hvwlpdwlrq ri Orqj Udqjh Ghshqghqfh/ Dqqdov ri Vwdwlvwlfv 56/ 4963094 Vplwk/ M1/ Q1 Wd|oru dqg V1 \dgdy +4<<:,/ Frpsdulqj wkh Eldv dqg Plv0 vshflfdwlrq lq DUILPD prghov/ Mrxuqdo ri Wlph Vhulhv Dqdo|vlv/ 4;+8,/ 83:0 85: Vrzhoo/ I1 +4<<5,/ Pd{lpxp olnholkrrg hvwlpdwlrq ri vwdwlrqdu| xqlydul0 dwh iudfwlrqdoo| lqwhjudwhg wlph vhulhv prghov/ Mrxuqdo ri Hfrqrphwulfv 86/ 4980;; Wd|oru/ V1M1 dqg [1 [x +4<<:,/ Wkh Lqfuhphqwdo Yrodwlolw| Lqirupdwlrq lq Rqh Ploolrq Iruhljq H{fkdqjh Txrwdwlrqv/ Mrxuqdo ri Hpslulfdo Ilqdqfh 7/ 64:0673 Wldr/ J1F1 +4<:5,/ Dv|pswrwlf Ehkdylrxu ri Whpsrudo Djjuhjdwhv ri Wlph Vhulhv/ Elrphwulnd 8</ 8580864 Zhl/ Z1Z1V1 +4<;4,/ Hhfwv ri V|vwhpdwlf Vdpsolqj rq DULPD Prg0 hov/ Frppxqlfdwlrqv lq Vwdwlvwlfdo0Wkhruhwlfdo Pdwkhpdwlfv D 43/ 56;<056<; Zrrg/ U1D1 +5333,/ Pdunhw Plfurvwuxfwxuh Uhvhdufk Gdwdedvhv= Klvwru| dqg Surmhfwlrqv/ Mrxuqdo ri Exvlqhvv ) Hfrqrplf Vwdwlvwlfv 4;+5,/ 4730478 ]krx/ E1 +4<<9,/ Kljk Iuhtxhqf| Gdwd dqg Yrodwlolw| lq Iruhljq0H{fkdqjh Udwhv/ Mrxuqdo ri Exvlqhvv ) Hfrqrplf Vwdwlvwlfv 47+4,/ 78085 54.

(35) D. Dsshqgl{= Hpslulfdo Uhvxowv. D14. Ghvfulswlyh Vwdwlvwlfv dqg Hvwlpdwlrq Uhvxowv. Iuhtxhqf|. Vnhz. Nxuwrvlv. EO +43,. GZ. ). )2. )

(36). )D. )f. )D. 4 Plq 43 Plq 58 Plq 4 Krxu 4 Gd|. 6319 4314 8159 7167 3137. 4765 743 535 475 8157. ;47 63; 477 8614 4519. 41:3 41:3 41:9 41<7 5133. 31485 31484 3144; 31364 3139<. 31464 313:4 0 0 0. 31448 3137< 0 31363 0. 313:5 0 0 0 0. 31365 0 0 03135< 0. 31356 0 0 0 0. Wdeoh 4= Ghvfulswlyh vwdwlvwlfv ri IWVH0433 uhwxuqv dw glhuhqw vdpsolqj iuhtxhqflhv1 EO+43, ghqrwhv wkh Er{0Omxqj Vwdwlvwlf zlwk 43 dxwrfruuhodwlrqv +4;164 fulwlfdo ydoxh dw <8I frqghqfh erxqg,1 GZ ghqrwhv wkh Gxuelq Zdwvrq whvw1 4 ghqrwhv wkh  | dxwrfru0 uhodwlrq1 Wkh vwdwlvwlfv duh fdofxodwhg xvlqj 43/333 revhuydwlrqv iru vdpsolqj iuhtxhqflhv grzq wr rqh krxu dqg 5/733 revhuydwlrqv iru wkh gdlo| iuhtxhqf|1 Wkh <8I frqghqfh erxqgv duh wkhuhiruh 3135 dqg ffe2 uhvshfwlyho|1 Hqwulhv zklfk frqwdlq wkh %0% v|pero duh qrw vljqlfdqw edvhg rq wkhvh erxqgv1. Uhdol}hg Yduldqfh Orjri Uhdol}hg yduldqfh Gdlo| Uhwxuq Vwdqgdugl}hg Gdlo| Uhwxuq. Phdq. Vwg1Ghy1. Vnhzqhvv. Nxuwrvlv. DGI+8,. ;187H08 0<1<; 7193H07 313<4. 518:H07 31<95 <15;H06 413<. 5415 3188; 31395; 313695. 8<9 7144 815< 5156. 04915 0;1;6 0541; 05516. Wdeoh 5= Ghvfulswlyh vwdwlvwlfv iru uhdol}hg yrodwlolw| dqg gdlo| uhwxuqv1 Wkh froxpq %DGI+8,% uhsruwv wkh dxjphqwhg glfnh| ixoohu whvw lqfoxglqj d frqvwdqw dqg 8 odjv 55.

(37) Prgho. Vdpsoh. _. k. q. ln . l3 . ln 2. l3 2. bf. OrjO. DLF2W. DUILPD. L. 31779. 31755. 031969. 0. 0. 0. 0. 0. 0:56. 31;4. . Uhwxuqv. L. 31748. 31635. 0318<:. 4;13. 0. 0786. 3184. . Yroxph. L. 317;4. 3164:. 0319:: +4816,. +491;,. +5319,. +:164,. +<197,. 491<. 316:<. 0699. 3175. DUILPD. LL. 317;:. 31734. 031975. 0. 0. 0. 0. 0. 0<9;. 31;3. . Uhwxuqv. LL. 317;7. 3165:. 031995. 471<. 0. 097<. 3187. . Yroxph. LL. 317;<. 3166<. 0319;7. 461<. 3168;. 086:. 3178. +<153, +:185, +4<1;,. +5<15, +5715, +6514,. +81<5, +7196, +916<,. +:157, +:145, +;139,. +;174, +:166,. +4614, +4913, +4<17,. 6619. +5314,. 5:1:. 5818. +5318,. 5418. +4:1:,. 6<17. +5418,. 6917. 6516. +5715,. 5<17. +551:,. 471;. +;1;9,. 441:. 4319. +;185,. ;195. +:155,. +<1::,. +4415, +431<,. +4619,. +4816,. Wdeoh 6= DUILPD hvwlpdwlrq uhvxowv1 Vdpsoh L uxqv iurp Pd| 5/ 4<<3 xqwlo Mxqh 48/ 4<<:1 Vdpsoh LL uxqv iurp Pd| 5/ 4<<3 xqwlo Mdqxdu| 44/ 53331 _/ k / dqg q  ghqrwh 3 wkh DUILPD+4/g/4, prgho sdudphwhuv1 l n  / l  / dqg bf / duh wkh uhjuhvvlrq frh!flhqwv ri fruuhvsrqglqj wr wkh | odj ri srvlwlyh dqg qhjdwlyh uhwxuqv dqg frqwhpsruhqhrxv wudglqj yroxph uhvshfwlyho|1 Wkh odvw wzr froxpqv frqwdlq wkh ydoxh ri wkh orj olnholkrrg ixqfwlrq dqg wkh Dndlnh lqirupdwlrq fulwhuld1 w0Vwdwlvwlfv duh uhsruwhg lq sduhqwkhvlv1. 56.

(38) D15. Plfur Vwuxfwxuh ) Vdpsolqj Iuhtxhqf|. 1. x 10. -4. Term 1 + Term 2. 0.8. 0.6 Term 1: Average Daily Realized Volatility "Optimal" Sampling Frequency Range. 0.4 Term 2: Autocovariance Bias Factor. 0.2. 0. 0. 5. 10. 15. 20 25 Sampling Frequency (minutes). 30. 35. 40. 45. Iljxuh 414= 4<<305333 dyhudjh gdlo| uhdol}hg yduldqfh dqg dxwrfryduldqfh eldv idfwru +grwwhg olqh lv xqfrqglwlrqdo yduldqfh fdofxodwhg xvlqj gdlo| uhwxuq gdwd,. 4. x 10. -5. 2. 0. Term 2: Autocovariance Bias Factor. 0. 5. 10. 15. 20 25 Sampling Frequency (minutes). 30. 35. 40. Iljxuh 415= Hpslulfdo +vrolg olqh, dqg djjuhjdwlrq lpsolhg +grwwhg olqh, Dxwrfryduldqfh Eldv Idfwru. 57. 45.

(39) D16. Wkh IWVH0433 Uhdol}hg Yduldqfh 4. -4. -6. 2. -8. 0 -10. -2 -12. -14 1990. 1992. 1994. 1996. 1998. -4 1990. 2000. Iljxuh 514= Orj ri uhdol}hg yduldqfh. 1992. 1994. 1996. 1998. 2000. Iljxuh 515= Iudfwlrqdoo| glhuhqfhg +xvlqj g@3173, orj uhdol}hg yduldqfh vhulhv1. 0.8. 0.15. 0.7 0.1 0.6 0.05 0.5. d=0.45. 0.4. 0. 0.3. d=0.40. -0.05. 0.2 d=0.30 -0.1 0.1. 0 0. 50. 100 150 Displacement (days). 200. 250. 0. 50. 100 150 Displacement (days). 200. 250. Iljxuh 516= Fruuhorjudp orj uhdol}hg yduldqfh. Iljxuh 517= Fruuhorjudp ri iudfwlrqdoo|. soxv iudfwlrqdo lpsolhg fruuhodwlrqv1. glhuhqfhg orj uhdol}hg yduldqfh vhulhv 0.8. 0. 0.7. -0.5. d=0.43. d=0.37 0.6. 0.5. -1. Robinson. 0.4 Geweke Porter-Hudak. -1.5 0.3. -2. 0. 1. 2. Iljxuh 518=. 3. *L} ). 4. yhuvxv. *L} . 5. 6. 0.2 25. 50. 75. 100. 125. 150 175 Bandwidth m. 200. 225. 250. Iljxuh 519= JSK ) Urelqvrq hvwlpdwh iru g dv d ixqfwlrq ri wkh edqgzlgwk p1. 58. 275.

(40) D17. Iruhfdvwlqj Shuirupdqfh. -5. 1.04. 1.8. x 10. 1.6. Sum of Squared Forecast Error. 1.03. 1.02 GARCH 2 1.01 ARFIMA. GARCH 1. 1. 1.4 1.2. GARCH 1. 1 GARCH 2 0.8 0.6 ARFIMA. 0.4. 0.99 0.2. 0.98 0. 50. 100 150 Forecast Horizon (days). 200. 250. 50. 100 150 Forecast Horizon (days). 200. 250. Iljxuh 614= Iruhfdvwhg glylghg. Iljxuh 615= Vxp ri vtxduhg huuruv ri iruh0. e| dfwxdo dyhudjh uhdol}hg yduldqfh. fdvwhg fxppxodwlyh uhdol}hg yduldqfh. -3. 4.5. 0 0. 10. x 10. 9 4. Standard Deviation Forecast Error. 8 3.5. 7 3. 6 GARCH 1. 2.5. 5 2. GARCH 2. 4. ARFIMA. 1.5. 3. 1. 2. 0.5. 1. 0 0. 50. 100 150 Forecast Horizon (days). 200. 250. 0 0.25. 0.3. 0.35. 0.4 0.45 0.5 Geweke Porter-Hudak Estimate. 0.55. 0.6. 0.65. Iljxuh 616= Iruhfdvw huuru vwdqgdug ghyldwlrq Iljxuh 617= Ghqvlw| Jhzhnh Sruwhu Kxgdn hvwlpdwhv. 59.

(41) E E14. Dsshqgl{= Wkhru| Whpsrudo Djjuhjdwlrq ) V|vwhpdwlf Vdpsolqj. Frqvlghu dq DUPD+s/t, surfhvv k Eu f| ' q Eu 0| c zkhuh k Eu dqg q Eu duh odj sro|qrpldov ri ohqjwkv R dqg ^ uhvshfwlyho|1 Frq0 vlghu wkh fdvh zkhuh wkh uhflsurfdov ri wkh urrwv ri k Eu ' f/ w c c wR / doo olh lqvlgh wkh xqlw flufoh1 Zkhq f| lv d vwrfn yduldeoh/ Zhl +4<;4, vkrzhg wkdw e| dsso|lqj wkh rshudwru 7Eu R \   w s us 7Eu '   w u  ' wr DUPD+s/t, surfhvv/ wkh DUPD+s/u, prgho wkurxjk zklfk wkh owhuhg vxe0 vhulhv pd| eh uhsuhvhqwhg lv rewdlqhg1 Lq wklv fdvh/ s ghqrwhv wkh v|vwhpdwlf vdpsolqj iuhtxhqf|1 Zkhq f| lv d rz yduldeoh/ Zhl +4<;4, vkrzhg wkdw e| dsso|lqj wkh rshudwru A Eu A Eu ' 7Eu.   us u. wr DUPD+s/t, surfhvv/ wkh DUPD+s/u, prgho wkurxjk zklfk wkh owhuhg vxe0 vhulhv pd| eh uhsuhvhqwhg lv rewdlqhg1 Lq wklv fdvh/ s ghqrwhv wkh whpsrudo djjuhjdwlrq iuhtxhqf|1 Wkh prylqj dyhudjh odj ohqjwk o lv jlyhq e| wkh lqwhjhu sduw ri R n ^3s R dqg iru odujh s zloo eh htxdo wr R ru R  / ghshqglqj rq zkhwkhu ^  R ru ^ R1 Qrwh wkdw dowkrxjk wkh rughu ri wkh dxwruhjuhvvlyh sduw ri wkh DUPD prgho uhpdlqv wkh vdph xqghu v|vwhpdwlf vdpsolqj ru whpsrudo djjuhjdwlrq/ wkh pdjqlwxgh ri wkh dxwruhjuhvvlyh frh!flhqwv ghfuhdvh h{srqhqwldoo| zlwk s 1 Khqfh/ lq wkh olplw wkh dxwruhjuhvvlyh sduw zloo glvdsshdu1 Pruhryhu/ iru us whpsrudo djjuhjdwlrq/ wkh whup 3 3u zloo grplqdwh wkh PD sduw dqg khqfh wkh olplw prgho lv dq DUPD+3/3, ru htxlydohqwo| zklwh qrlvh1. E15. Iudfwlrqdo Lqwhjudwlrq. D wlph vhulhv/ f| lv vdlg wr eh iudfwlrqdoo| lqwhjudwhg ri rughu _/ li diwhu dsso|lqj wkh glhuhqfh rshudwru Eu_ lw iroorzv d vwdwlrqdu| DUPD+s/t, surfhvv zkhuh 5:.

(42) R dqg ^ duh qlwh qrqqhjdwlyh lqwhjhuv1 Wkh frqfhsw zdv ghyhorshg e| Judqjhu +4<;3/ 4<;4, dqg Judqjhu dqg Mr|hx{ +4<;3,1 D w|slfdo ihdwxuh ri d iudfwlrqdoo| lqwhjudwhg ru orqj phpru| surfhvv lv wkdw wkh hhfw ri d vkrfn wr wkh surfhvv lv kljko| shuvlvwhqw exw ghfd|v ryhu wlph1 Wklv/ dv rssrvhg wr UE surfhvvhv zkhuh d vkrfn kdv lqqlwh shuvlvwhqfh ru dw wkh rwkhu h{wuhph UEf0surfhvvhv lq zklfk wkh hhfw ri d vkrfn wr wkh v|vwhp ghfd|v h{srqhqwldoo| idvw1 Pruhryhu/qrwh wkdw wkh iudfwlrqdo glhuhqfh rshudwru wdnhv fduh ri wkh orqj uxq g|qdplfv zkloh wkh DUPD vwuxfwxuh fdq dffrxqw iru wkh vkruw uxq g|qdplfv1 Wkh DUILPD+s/g/t, prgho fdq eh zulwwhq dv kEuE  u_ f| ' qEu0| c. +7,. zkhuh kEu lv d odj sro|qrpldo ri rughu R dqg qEu ri rughu ^1 Qrwh wkdw wkh DUPD+s/t, dqg Lqwhjudwhg DUPD+s/t, prghov duh vshfldo fdvhv ri +7, iru _ ' f dqg _ '  uhvshfwlyho|1 Xvlqj d elqrpldo4: ru Wd|oru0olnh h{sdqvlrq +durxqg u ' f,/ wkh iudfwlrqdo glhuhqfh rshudwru fdq eh h{suhvvhg dv iroorzv=   E  u_ '   _u  _E  _u2  _E  _E2  _u

(43)     2 S " [ KE  _ ' u KE n KE_ 'f " T E?    _ [ ?' u ' n '. +8,. Xvlqj Vwluolqj*v irupxod4; lw fdq eh vkrzq wkdw= T K E  _ ?' E?    _ ' 2 3_3 K E_ K E n  iru  odujh1 Pruhryhu/ iru _ .  2. dqg _ 9' f/ lw fdq eh vkrzq wkdw=. ) ' SJooEf| c f|3  '. KE  _ KE n _ 2 2_3 KE_ KE n   _  odujh. +9,. dqg khqfh wkh ghfd| ri wkh fruuhorjudp lv k|shuerolf/ dv rssrvhg wr dq h{sr0 qhqwldo ghfd| iru dq U Ef surfhvv1 Iru _ ' f/ ) ' f iru  : f Wkh surfhvv O,g. S4 k@3. . g k. . +4,k Ok zkhuh Wkh Elqrpldo Wkhruhp vwdwhv wkdw +4  @   g +4,k @ +k  g,@ ^+g,  +k . 4,` dqg +, lv wkh Jdppd ixqfwlrq iru zklfk lw k krogv wkdw +{, @ +{  4,  +{  4, s k. d, 4; d e Vwluolqj*v irupxod vwdwhv wkdw  +k,  5kk4@5 hk iru k odujh dqg khqfh + +k.e,  k 1 4:. 5;.

(44) lv vwdwlrqdu| dqg orqj phpru| iru f _ fD1 Wkh surfhvv lv vwdwlrqdu| dqg lqwhuphgldwh phpru| zkhq fD _ f1 Iru _  fD/ wkh surfhvv lv qrq0vwdwlrqdu|1 E1514. Orj0Shulrgrjudp Uhjuhvvlrqv. Vhyhudo wzr vwhs surfhgxuhv kdyh ehhq sursrvhg wr hvwlpdwh wkh iudfwlrqdoo| lqwhjudwhg DUPD prgho1 Wkh pdlq lghd lv wr hvwlpdwh wkh iudfwlrqdo sdudp0 hwhu/ _/ lq wkh uvw vwhs zkloh lq wkh vhfrqg vwhs wklv hvwlpdwh fdq eh xvhg wr iudfwlrqdoo| glhuhqfh wkh revhuyhg vhulhv/ wudqviruplqj lw lqwr dq DUPD sur0 fhvv ri zklfk wkh sdudphwhuv fdq eh rewdlq vwudljkwiruzdugo| e| ruglqdu| ohdvw vtxduhv1 Jhzhnh Sruwhu0Kxgdn +4<;6/ JSK khuhdiwhu, sursrvh wr hvwlpdwh _ e| d orj0shulrgrjudp uhjuhvvlrq zklfk lv ghvfulehg ehorz1 Frqvlghu Eu_ f| ' 0| zkhuh 0| lv d vwdwlrqdu| olqhdu surfhvv zlwk vshfwudo ghqvlw| ixqfwlrq s0 Eb zklfk lv qlwh/ erxqghg dzd| iurp }hur dqg frqwlqxrxv rq wkh lqwhuydo dZc Zo1 Wkh 3_ 2  s0 Eb ru htxlydohqwo| vshfwudo ghqvlw| ixqfwlrq ri if| j lv s Eb ' jZ e t? b 2. 2. *? s Eb ' *?.   j s0 Ef s0 Eb  _ *? e t? Eb*2 n *?  2Z s0 Ef 2. +:,. 2. Ghqh wkh kduprqlf iuhtxhqf| b ' AZ zkhuh A lv wkh vdpsoh vl}h dqg ohw U Eb  eh wkh shulrgrjudp dw b zklfk lv jlyhq e| 2.   A   [   b |  U Eb  ' f| e     2ZA  | 2. '. Uhduudqjlqj whupv dqg hydoxdwlqj h{suhvvlrq E. dw b forvh wr }hur +wkh whup *? ss00 b lv wkhuhiruh qhjoljleoh, wkh iroorzlqj h{suhvvlrq lv rewdlqhg= E. . Ef. *? U Eb  ' *?.   j s0 Ef U Eb   _ *? e t? Eb *2 n *?  2Z s Eb  2. +;,. 2. Wkhuhiruh/ wkh frh!flhqw _ fdq qrz eh hvwlpdwhg dv wkh vorsh frh!flhqw lq   d ohdvw vtxduhv uhjuhvvlrq ri *? U Eb  rq d frqvwdqw dqg *? e t? Eb *2 iru  '  n ,c    c 6  A JSK vhw , ' f dqg uhtxluh wkdw wkh edqgzlgwk sd0 udphwhu 6 lqfuhdvhv dw d vorzhu udwh wkdq wkh vdpsoh vl}h1 Lq pdq| sudfwlfdo dssolfdwlrqv 6 lv vhw wr htxdo wr wkh vtxduh urrw ri wkh vdpsoh vl}h A 1 Urelqvrq +4<<8d, surylghv wkh dv|pswrwlf ehkdylru ri wkh hvwlpdwru1 Lq dgglwlrq/ Urelq0 vrq +4<<8e, sursrvhg dq dowhuqdwlyh hvwlpdwru zklfk lv ghulyhg xqghu zhdnhu 2. 5<.

(45) frqglwlrqv dqg suryhg wr eh dv|pswrwlfdoo| pruh h!flhqw wkdq wkh JSK hvwl0 pdwru1 Wklv hvwlpdwru/ iru wkh iudfwlrqdo sdudphwhu/ lv jlyhq e| wkh ydoxh ri _ wkdw plqlpl}hv wkh iroorzlqj remhfwlyh ixqfwlrq= % & 6  3 _  b _  [ U Eb  c *? Sb ' ESc _ ' n 6 S 2. 2. '. zkhuh S : f dqg _ lv uhvwulfwhg wr olh ehwzhhq  dqg 1 E1515. . . 2. 2. H{dfw Pd{lpxp Olnholkrrg. Prwlydwhg e| wkh qglqj wkdw wkh DUPD sdudphwhuv duh jhqhudoo| qrw hvwl0 pdwhg dffxudwho| xvlqj d wzr vwhs phwkrg/ Vrzhoo +4<<5, sursrvhv dq h{dfw pd{lpxp olnholkrrg surfhgxuh wkdw hvwlpdwhv doo prgho sdudphwhuv vlpxowdqh0 rxvo|1 Ohw P ghqrwh wkh fryduldqfh pdwul{ ri wkh mrlqw glvwulexwlrq ri if| j|| A zkhuh f| lv dvvxphg wr iroorz dq DUILPD+s/g/t, surfhvv dv jlyhq e| h{suhv0 vlrq Ee1 Wkh prgho sdudphwhuv fdq eh hvwlpdwhg e| pd{lpl}lqj wkh iroorzlqj orj0olnholkrrg ixqfwlrq ryhu wkh sdudphwhu vsdfh '. '.     A *L} u _c kc qc j 0 '  *L} E2Z  *L} mPm  f P fc 2 2 2 zkhuh P ' )   iru c  ' c 2c    c A / lv h{suhvvhg lq whupv ri wkh prgho sdudphwhu1 Vrzhoo +4<<5, vkrzv wkdw wkh fryduldqfh pdwul{/ qhhghg iru wkh hvwlpdwlrq/ lv jlyhq e| 2. . 3. ƒ 3 ƒ. )r ' j0. 2. R ^ [ [ ,'3^  '.   i E, y  _c R n ,  rc ). zkhuh. ^c^ , [. 4?d. i E, '. y ' w 3. R \ '. q rq r , 3. r'4@. dqg. 3 o. c,o. df. E  w w . \ 6 '. Ew  w6 . zkhuh w ghqrwh wkh urrwv ri kEu dqg duh dvvxphg wr olh rxwvlgh wkh xqlw glvn1 Ilqdoo|/ wkh h{suhvvlrq iru  lv jlyhq e|    E_c c w ' } E_c  w R 8 E_ n c (   _ n ( w n 8 E_  c (   _  ( w   2. zkhuh } E_c  ' wlrq1. _ _  _ KE3_KE_. KE32 KE n KE3 n. dqg 8 E@c K( S( e lv wkh k|shujhrphwulf ixqf0. 63.

(46)

Riferimenti

Documenti correlati

Although the 6MWT is the most frequently used test to as- sess physical performance in older patients receiving cardiac rehabilitation (10, 12), little is known on the

A number of different terms are used to characterize supero anteroinferior labral injuries based on their patho-anatomy: Bankart lesion (complete detachment of

Figure 9 highlights that for both adhesives the shear strength of the hybrid interface (bonded and pressure. reinforced) linearly increases with nominal contact pressure upon that

Version 1.0 will be an online catalog of pure compounds and reference materials (food extracts, biofluids from animals fed pure compounds, incubation media from

Although SZAFER (1961) suggested that two species occurred in the Neogene of Europe, the distinction was only based on fruit size, and TRALAU (1963) reported that fruit size

 try to implement the concept and the requirement of quality within the school; For this purpose educational initiatives could be expected, managers and teachers to introduce

This geo-database was used to produce maps (e.g. susceptibility, ground deformation velocities, damage assessment, risk zonation) which today are constantly used by the Civil

However, field mapping and struc- tural analysis carried out in most of the hinterland basins show relationships between sedimentation and tectonics pointing to a