HAL Id: inria-00115528
https://hal.inria.fr/inria-00115528v3
Submitted on 22 Nov 2006 (v3), last revised 23 Nov 2006 (v4)
HAL is a multi-disciplinary open access archive for the deposit and dissemination of sci- entific research documents, whether they are pub- lished or not. The documents may come from teaching and research institutions in France or
L’archive ouverte pluridisciplinaire HAL, est destinée au dépôt et à la diffusion de documents scientifiques de niveau recherche, publiés ou non, émanant des établissements d’enseignement et de recherche français ou étrangers, des laboratoires
A Bayesian analysis of industrial lifetime data with Weibull distributions
Nicolas Bousquet
To cite this version:
Nicolas Bousquet. A Bayesian analysis of industrial lifetime data with Weibull distributions. [Research
Report] 2006, pp.24. �inria-00115528v3�
a p p o r t
d e r e c h e r c h e
Thème COG
A Bayesian analysis of industrial lifetime data with Weibull distributions
Nicolas Bousquet
N° ????
Novembre 2006
Unité de recherche INRIA Futurs
213547698;:=<?>@69A <CBAED7F
GIHKJL?MON P'QSRUTWVYX[Z\JL?MCX ]^`_7aKbcZ\bcdeX
fhgi^`j[MZkTWlhml#N#G
no`pKpq^7grZsYMtg\MC]+HuMg+]+HKMva=w xyxyxzx0R|{^"}7MLO~KgiMt7`tRUY'puo`_`MCX
1 EC"K`` Z\HKM]^7aZiMWZ^`d ^7KgXrZiusYVbX baqsYuXrZig\bo`giMCbo~ubbcZ[V7K HKMCgiM'bcdMZibL@M@sKo"Z+o?og\MtuXrqoV]MaqXr^7giMzs
o`aus1ba0XrLo9aWKL~=MgzIo`]+W_`g\^`Kaqs?baYd^7giLoZib^`abXIoy}"obo`~KMdg\^`L*MYpqMCgrZ+XhPkKgIpKg\b^7g XrK~Kj[MC]Z\b}7M'au^" c
MzsY_`MkbX^`aKVo~=^`YZZiHKMbcdMZibL@M^do`abausYuXrZig\bo`=]^`L?p=^`aKMCa7ZIoausaK^ZIo~=^`YZZiHKMpuog+oL?MZiMg+X^`do ¡Mb~KK
sYbXrZig\b~KKZib^`a¡ HKb]+H¡g\MpKg\MCXiMaZ\XZiHubX'bcdMZibL?M`? ¢Mpugi^7pq^XrMZi^d^Y]uXZ\HKMsYbX\]qXiXib^7a¢~=MZ[#MMCa£Z\HKMMYp=MgiZ\X
o`ausOZiHKM bausYuXrZig\boKoaqoVWXrZo~=^`YZZ\HKMXib¤CM ^d¥z¦¨§©5ªu«"¬sKoZ\ogiMCpKg\MCXiMaZibaK_kZiHKM }"og\bo~KbbZ[V^`dqZ\HKM MYp=MgiZ^`pKbaY
b^`aE®ausYMCMCs¯7ZiHubXXrb¤M bX^`auM ^d9ZiHKMkXi]Cog+]MIbaqsYb]Co"Z\^`g+XEZiHuoZh~q^`ZiH]Coa?KausYMCg\XrZ\o`aus¯ GIHKMpKg\b^`g]o`b~Kg+o"Z\b^7aObX
Lo`sKMMzo`XiV`Ko`aus0Xr^7L@M'L?MZ\HK^YsKXo`aus1bausYb]oZi^7g\XIbau]usYbaK_osYMdeoKZ]o`b~Kg+o"Zib^`aL?MZiHu^Ws0o`giM'pKg\^`p=^7XiMCs1Zi^
HKMCp°ZiHKM@IoyV`MCXiboa£oaqoVWXrZO±ZiHKMCV£]oa°~qM@MWZiMCausYMzs0Zi^baKdMg\Mau]MCXk^`a£^`ZiHKMCgsYbXrZig\b~KKZib^`auXZiHuo`a£ ¡Mb~KK²
#MCXibsYMCXC`Z\HKMpq^X[Z\Mg\b^7gh]^7L@puYZ\oZib^`a~WV?bL?p=^`giZ\o`au]MXio`L@pubaK_bXIXrbL?pKMoaus1XioZibX[dVWbaK_u ³Ebauo`V`Z\HKgi^7K_`H
o@g\MCo¯MKoL?pKM`WZiHuM'´uMYb~KbbZ[V^dEZiHKMtMCb]bZ\oZib^`abXbqX[Z\g\oZiMCs
µ·¶¸9¹iºO» "¼E` g\Mbo`~KbbZ[V`qsKKg\o`~KbbZ[V`9IoyV`MCXiboa0oauo`VYXibXCu ¡Mb~KKEsKbXrZig\b~uYZib^`a=MYp=MgiZ^`pubaKb^`a=XiK~Yj[Mz]
Z\b}7Mpugib^`gzY}WbgiZiuo`sKo"Z+oKK]MauXi^`g\MCssKo"Z+oKK½'K~qo`]+;mMb~KMg
- / #E0t/0
]MZrZ\MZiqsYM XrM#pKo`]M sKo`auXEM ]Co`sYg\MsYMIoqo~KbbcZ#MZsYMo'sYKg+o~KbbcZbausYuXrZig\bMM7kMCXsY^7aKaCMCX
]MauXiKgMCXsYMsYKgMsKM}WbMs Ka¢XrVYXrZiJL?MXi^`aZksYbXipq^7aKb~uMzX=XrVYXrZiJL?MsK^`aZ^`a·L?^Ys!bXrMM]^`L?pq^7grZ\ML?MaZ
o` ]^`ug\XOsY ZiMCL?puX@puogOKaKM1^`b#X[Z+o"Z\bXrZib#"KMsYM ¢MCb~uK%$Z\giJzX_&aCg\o`MCL?MaZCE^`a!XiKpKp=^7XiM1sY^7au]'"KM]M
]^`L?pq^Xio`aZ}WbMCbbcZz(kMCX MYpqMCgrZ+XbausYqX[Z\gibMX Xr^7a7ZsYbXrp=^`aub~KMCX p=^`ug o`L)b^7giMCg*MzX[Z\bLoZib^`a?sYMCXEpuo`g\o`L@JZig\MCX
sYOL?^WsKJM`Y¥z¦e«sKMCXZiMz]+HKaKb#"7uMCX s+baYd,CgiMCau]M#~uoyV&CXibMCaKaKM`®X X-MWpugibL?MaZEXiKgiZi^`KZEMCaZiMCgiL?MzXsYMIsYKgMIsYM#}WbM
MZEaK^7aOsYM#}"oMKg+XpuogiZib]KbJg\MCXEsYOpqog+oL?JZ\giM7m.^`~Yj[Mz]Z\bcdqsKM#]Mg+opKp=^`giZMzX[ZsYM#pKg\^`p=^7XiMgEKaKM#L@^Ys!CbX\o"Zib^`a
«0/=¦21§¦sKMCXpuog+oL?JZig\MCX'"Kb'g\MCXipqMz]Z\M¡]MZrZ\M¡]^`aZig+obaZiM¢MZ0giMzX[Z\M¢]MCpqMCausKo`a7Zdeo`]bML?MCa7Z·]o`b~Kg+o~KM°pqog
Ka o`auoVYX[Z\M~uoyV3zXrbMa¡bausYuXrZig\bMC'oY ]^`auauobXiX\oaq]MCXtXrZ\oZibX[Z\b4"KMzXXi^`K}7MaZbL?bZ5MzXtpqogM~KbobXs+Ka
HWVWpqMCgipqog+oL?JZ\giM°]^`g\giMzXrp=^`aqsKoaZ'6KaKM¢Z\obM¡sYM¡sK^`aKaCMCX'q]Z\b}7MCXCNMZiZiM¢Z\obM7ko`]C]^7g\s!CM76 *MYpqMCgrZz
]^`auXrZibZiKMKabaqsYb]Co"Z\MKgh]^`L?pKgHKMCauXib~KMsYM*baYd^7giLoZib^`a£«8/=§¦21"§¦uMZhp=Mg\L?MZhotsYbXi]uXiXib^`a?MaZig\M *MWp=MgiZ
MZ?*oauo`VYXrZiM` Pka pqMCYZMYpKg\bL?MCgM0g+opKp=^`giZ?sKM*baYd^7giLoZib^`a XrK~Kj[MC]Z\b}7M·XrKg*baYd^7giLoZib^`a!^7~Yj[MC]Zib}`M
±opKp=^`giZ5CMOpuo`g'MzXtsY^`aKa9MCX+²MZ'deo`]bbcZ\MgtobauXibM@Z\g\oy}"ob sYM?L@^Ys!Cg\oZib^`a¡sYM?:oauo`VYXrZiM7<;aKM?L)Z\HK^YsYMsYM
]Cob~Kg+o"Z\b^7a1puo`gs!deo`YZMCXrZ puogo`bMKg+XIpKg\^`p=^7X5M`
= » C ¹ &> ¢ qo~KbbcZ@bausYqX[Z\gibMM?$baYd,CgiMCau]M?~uoyV&CXibMCaKaKM$^`pubaKb^`a s+MYp=MgiZ)$EsYbX[Z+oau]M?sKM?½'u~uo`]+
mMb~KMCg@$u]o`b~Kg+o"Z\b^7a¡«A/9§¦21"§¦($usY^7aKaCMCX ]MCauXiKg5CMCX%$YL?^YsYJMsYMt ¡Mb~KK
O h
®a!o£giMCbo~KbbcZ[V¡]^`aZ\MWZC ^`auM^d Z\HKML?^7XrZOMCL@pu^"V7MCs¡bdMZ\bL?M0sYbX[Z\gib~KYZ\b^7auXbXtZ\HKM1 ¡Mb~KK#sKbXrZig\b~uYZib^`a
±moy MCX\Xk YY]+Huop"!W²GIHKbXI}`MCg\X\o"Z\bM
W(η, β)
sYbXrZig\b~KKZib^`aK bZiH·sYMCauXibcZ[Vduau]Z\b^7af W (t|η, β) = β η
t η
β−1
exp (
− t
η β )
o`aus Huo¤zog+s°g+o"Z\M
h W (t|η, β) = β η ( η t ) β−1
HKMCgiMη, β > 0
]o`a ~qMqXrMzs¡d^`gL?^YsYMCbau_·baYdeo`aZL?^`giZ\obZ[V sYMdMC]Z\X HuMa ZiHuM1XrHqop=Mpuog+oL?MZ\Mgβ < 1
o_`baK_0 HKMCaβ > 1
^`go7]]bsYMCaZ\odeobKg\M£± bZiHo·]^`aqX[Z+oaZ g+o"Z\Mz² HKMaβ = 1
®aZ\HKbX]o7XrM7YbcZg\MCsYq]MCXZ\^oaMYpq^7aKMaZ\bo`sYbXrZig\b~KYZib^`a0 bZiH·X\]oMpuog+oL?MZ\Mgη
®a£aWKL?Mg\^`qXbausYuXrZig\bo`XrZiusKbMzX=giMCbo~ubbcZ[V#$$+«%$&'( /)§¦ *%@¬c¦©5¦+#?± ³Elhm²ksKo"Z+o
t n = t 1 , . . . , t n
o`giM·^`d¨ZiMa L?^YsYMCMCs bZiH Z\HKM£ ¡Mb~KKksYbX[Z\gib~KYZ\b^7a oaus Z\HKM£puo`g\o`L?MZiMCg\Xo`giM0MzX[Z\bLo"Z\MCs ~WV L?oYbLOKL
b7MbHu^^Ys·baYdMCgiMCau]MOuXrbaK_{MIZ\^`aY®no`pKHuXi^`a ±e{kn²^`gl-, o_`^7gibZiHuL?XC/.^"MC}`MCgCYZ\HKM@_`^W^Ys·~qMCHuoy}Wb^7g^d
b7MbHu^^YsOLo"YbL?b¤CoZib^`a?bX MCauXiKgiMzs@^`aKV HKMCaOZ\HKMX\oL?pKM Xrb¤M
n
bXo`gi_7MMCaK^`K_7HoausO HKMa@Z\HKMbcdMZibL@MzX o`giMbZrZiMk]MauXi^`g\MCs·±Io`]+Huo77²PZiHKMCgi bXiM`uXrbaK_IoyV7MCXibo`a@baYdMCgiMCau]MZiMC]+Hub4"KMzXhbXg\MM}"oaZ# HKMapugib^`gWaK^" MCsY_7M'bXoy}"o`bo~KM±en ^7~qMCgrZ'`uz²GIHKbXbXZiHKM]^`aZiMZ^`d^`KgXrZiusKV`u HuMg\MXr^7L@MtMYpqMCgrZ+XIpKgi^"}WbsYMCs
baYd^`g\Lo"Z\b^7auXo~=^`KZZiHKMObdMZ\bL?M
T
^doa·bausYuXrZig\bo]^`L?p=^`aKMCa7ZP
GIHKML?o`ba£sKb10]ucZ[V0bX Zi^Zig+oauXioZiM Z\HKbXIMYpqMCgrZ ^`pubaKb^`aba7Z\^?baYd^7giLoZib^`a1^7a(η, β)
uZiHKg\^`u_`HZ\HKM]+HK^7b]Mk^`dEo@pKg\b^7gIsKbXrZig\b~uYZib^`a bcZ\H·sYMauXibZ[Vπ(η, β)
hGIHuMaZiHKMtp=^7XrZiMCgib^`g sYMCauXibcZ[Vπ(η, β| t n ) = L( t n ; η, β) π(η, β) Z
IR
Z
IR
L( t n ; η, β) π(η, β) dηdβ
o`^"X#Zi^^7~YZ\o`ba·MzX[Z\bLoZiMCX^d giMCbo~ubbcZ[VdKau]Zib^`auX
h(η, β)
Hub]+H£o`giMt^`d baZiMCgiMzX[Z d^7gZiHuMbaqsYuXrZig\bo`oaqo"VYX[ZzKo`X#ZiHuMXrKg\}Wb}"o`9dKau]Z\b^7a2.MCgiM
L( t n ; η, β)
sKMaK^`ZiMCX ZiHKMtb7MbHu^^Ys^dZiHKMsKoZ\ouGIHKbXogiZib]M1bX@d^Y]uXiMCs!^`a Z\HKM·]+HK^`b]M^d
π(η, β)
! ¡M0]^`auXibsYMg@ZiHqo"Z@ZiHKM0MYp=MgiZz±X\²±e]^`auXibsKMg\MCs!o7X LoM7±X\²'d^`gXibL?pKb]bZ[VY²]o`a¡MYpKgiMzXiXHKbX±¨Z\HKMbg+²~qMCbMdeX^`aKV o~=^`YZZ\HKMLog\_`bauo`sYbXrZig\b~KYZib^`aM
^`dT
bZiH·sYMCauXrbZ[V
m(t) = Z
IR
Z
IR
f W (t|η, β)π(η, β) dηdβ
o`ausaK^`Z#sYbgiMz]Z\V?o~=^`YZ
(η, β)
¢MkZ\o``Mpugi^3KZh^d¯Z\HKbXhdMzo"Z\KgiMZi^~uKbsopKgib^`ghd^`ghZiHKM'Xi]CoMpuo`g\o`L@MZig\b¤zo"Z\b^7a@^`d9ZiHKM ¡Mb~KKqL?^YsYMC±eXiMMfhgi^7pz²GhVWpKb]o`V``HKM±¨Z\HKMVK²]Coa?_`b}`M pugib^`gMzX[Z\bLo"Z\MCX^`dqZ\HKML?MCo`aZ\HKM
L?MCsKbo`a9ZiHKM?L?^YsYM?^`gpqMCg\]MaZibMCX^d
M
3.^"#M}7Mgz=HuM±ZiHKMCVY²']Coa¢Huoy}`M@sYb10]KcZ\bMzXZi^MCXrZibLo"ZiM?HKbX'XrMCcdKaq]MgiZ\o`baZ[V $¯bausYMMzs¯o`a¢MWp=MgiZ'bX^d¨Z\Ma¡aK^ZoX[Z+o`XrZibX[Z\b]bo`a¢o`aus£aK^`Zib^`auX'o7XXrZ\o`ausKo`g\s£sKM}WboZib^`a¢giMCL?o`ba
dK¤C¤V7G^^`~KZ\oba°_7^W^Ws°MCXrZibLo"Zib^`aqX^`dhZiHubXpKg\b^7gkuau]MCgrZ+oba7Z[V7sYbXi]uXiXib^`auXk~qMZ[MCMa°ZiHKM?MYp=MgiZ'o`aus·Z\HKM
IoyV`MzXrboaoauo`VYXrZt±e HK^_7oZiHKMCg\XZ\HKMtpKg\b^7g#baYd^7giLo"Z\b^7aYp=^7X\Xrb~KVMCb_7HZIbZoaqsZ\HKMa0baYdMg~=^Z\HZiHKMsKoZ\o
o`aus?ZiHuMpKg\b^7g+²og\MsYMCXibg\o`~KM7".Mau]MZ\HKMaKMCMCs^`dbaqsYb]Co"Z\^`g+X HKb]+H1og\MKaqsYMg+X[Z+oausuo~KM d^`g~q^`ZiH^d¯ZiHuML0
4
d¨Z\MgXi^`L?M@giMz]oXko`aus£pKg\MC]bXib^`auX'o~=^`KZkZ\HKM?L@MzoaKbaK_^dZ\HKM? ¢MCb~uKpqog+oL?MZ\Mg+Xba¡TWMz]Z\b^7a WM
pKg\^`p=^7XiMba·TWMC]Zib^`a5Oo`a1bL@pugi^"}7ML?MaZ^`dZ\HKMtopKpKg\^7o7]+HpKg\^`p=^7XiMCs~WV#Mg\_`MCg#o`ausTYKa¡±r67²hoausIo`]+Huo
©«"¬87±r6 7²Zi^@Mb]bcZIpKg\b^7g#sYbXrZig\b~KKZib^`auXCGIHKML?o`bapq^7baZ ^dZiHKbX#bL?pKg\^"}`MCL@MCaZbX#Zi^?]^`aqXrbsYMgZiHuMpugib^`g
sYbXrZig\b~KKZib^`ao`Xo`a@o`pKpKg\^yWbLo"Z\b^7a^dqZiHKM p=^7XrZiMCgib^`gsYbXrZig\b~KKZib^`a]^7L@baK_dg\^`L o'aK^7aKbaYd^`g\Lo"Zib}`M#pKg\b^7goaus
¥z¦¨§©ªu«¬9`«©;« Hu^7XiM'Xib¤M
a
bXo@giMCMC}yo`aZIbausYb]oZi^7g#^`dEuau]MCgrZ+oba7Z[V7! t¦% 1"¬« 1ªª)©
4
]]^`g+sYbaK_?ZiHKM@Xrp=MC]b=]o"Z\b^7auX^`d ZiHKMOpKgib^`gau^" MzsY_`M7KM^`~YZ+oba£o?´uMYb~KMHKbMg+og+]+HKb]Co¯pKg\b^`g deo`L@bV
d^7g@ Hub]+HMpKg\^`p=^7XiMXi^`L?M0X[Z\g\oZiM_7bMzX^`dk]o`b~Kg+o"Z\b^7a ba TWMz]Zib^`a !KlhXrp=MC]bo`V`#o¢sKMdeoucZ]o`b~Kg+o"Z\b^7a
L?MZ\HK^Ys°bX'Xru_`_`MzX[Z\MCs¯t®aqsYMp=MausKMaZiV0dgi^7L ZiHKM?MWp=MgiZC9Z\HKMIoyV`MCXiboa£oaqoVWXrZkLOuXrZ'^`d¨ZiMCa°pKg\^Y]MMzs·Z\^o
uaqog\MC]Cob~Kg+o"Z\b^7aXrZiMCph®a0Z\HKbXkobL0uoa0bausYb]o"Z\^`g L?MCo7XrugibaK_@ZiHKMM9MC]Z\b}7MXrb¤Mt^`dZ\HKM]MauXi^`g\MCssKo"Z+o`XiMZ
t n
bX_`b}`Ma¡Z\^·^Y]oZiMZ\HKM1XrZig\MaK_7HZ^dIZiHKMXrK~Kj[MC]Z\b}7MbaYd^`g\Lo"Zib^`a bZiH g\MCXipqMz]ZZ\^·ZiHuM1X[Z\giMCaK_`HZ^`d#Z\HKM^7~Yj[MC]Zib}`MsKoZ\o0baYd^`g\Lo"Zib^`a#MCXibsYMCXC~ub~Kb^`_`g+opuHKb]Cog\MCXiKZ\Xo`giMg\MC]CoMzs¢o`aus ]o`a¡~=M1pugi^Y]MCMCsYMzs¡ba o
g\Mbo`~KM'o`ausXrbL?pKMtIoyV` GIHKMCaZ\HKM]^7auXiMauXiuXI~=MZ[#MMa0XiM}`MCg\o`9MYpqMCgrZ+XIbXI~ugibM´uVX[Z\usYbMCs¯
³EbaqoV7#M?XiHK^"ba TWMz]Zib^`aZiHqo"Z'ZiHKM]^`L?pKYZ+o"Z\b^7a¡^`dhZ\HKMpq^X[Z\Mg\b^7gtsYbXrZig\b~KYZib^`a bXtXrbL?pKMuXrbaK_
o`abL?pq^7grZ+oau]M'X\oL?pKbaK_o_`^`g\bZiHKL0®a·TWMC]Zib^`a·KKo@dKIoyV`MzXrboaoauo`VYXibX#bX MCsd^`g g\MCo`9suo"Z\oo`aus1Z[^
MWp=MgiZ ^`pKbaKb^`auX#Z\^buX[Z\g\oZiMZiHuMtL?o`bap=^`ba7Z+X ^dE^`Kg MCb]bZ\oZib^`aL?MZiHu^Ws
'% 0t $%#I
!"$#%&(')
³u^`g
n ∈ IN ∗
kMZT n = T 1 , . . . , T n ∼ W(η, β)
~=M¢bausYMCpqMCausYMCa7Z\V o`aus bsYMCa7Z\b]CoV sYbXrZig\b~KKZiMCs giMzo^7gr;}`Mz]Zi^7gr;}"oKMCs°g\o`ausY^7L }"og\bo~KMCXtba Z\HKMX\oL?pKMXipuo`]M
IR n +
bcZ\H pKg\^`~uo`~KbbZ[V¡sYMCauXibcZ[V¢dKau]Zib^`a ±ep=sWd+²f W (t|η, β)
oausXiKgi}Wb}"o±g\Mbo~KbbZ[VK²hdKau]Z\b^7aS W (t|η, β)
GIHKM@oy}yo`bo~uMsKoZ\oog\Mo`X d^7^"X+*MZ
t n = (t 1 , . . . , t n )
~=MOoa°^`~uXiMg\}`MzsX\oL?pKM^`dn
suo"Z\ou ;Xiuo`Vt n
]^`aZ\o`baqXr
uau]MCauXr^7giMzs°¦7¦77suo"Z\ox r = (x 1 , . . . , x r )
d^7^" baK_W(η, β)
o`ausn − r
KYMCs ±pugi^7_`g\MCX\Xrb}`M Z[VWp=M;r²'gib_`HZi;]MauXi^`g\MCs°}yo`uMCXCEsYMCaK^Z\MCsc n − r = (c 1 , . . . , c n−r )
·GIHWuXCZ\HKM^7~uXrMCgi}7MCs¢b`MCbHK^W^Ys ]o`a¡~=M g\bcZiZiMCa0o7X
L( t n ; η, β) = β r η r
r
Y
i=1
x i
η β−1
exp
−
n
X
j=1
t j
η β
.
, -./ #01#324"$5768:90;01=<0 >@?A(&/>B
GIHKMIuXiuo`Y ¢MCb~KuKpqog+oL?MZ\Mg+X
(η, β)
Huoy}7M#sYbC9Mg\MaZhXrMCauXiMCXCGIHKMX\]o`M#puog+oL?MZiMgη
bX Z\HKM63
DFE p=Mg+]MCaZibM^`dZiHuMsYbXrZig\b~KYZib^`a·o`aus1bX HK^7L?^`_`MCaKM^7uXhZi^
T
#YZ ZiHuMXrHuo`pqM'puo`g\o`L?MZiMCgβ
Hqo`XIaK^sYbL?MauXib^7a4 a0MWp=MgiZ}WbMC pq^7baZo~=^`KZ
β
o`pKp=MCog+XZi^?~=MGªu«¬¦¨©;«©¦¨¥*ZiHKMt}"o`KMt^`dβ
g\M´uMz]Z\X o@WaK^" MCsY_7Mo`~q^7YZ Z\HKM(/=§1*/ $%©¦¨¥#±^7gdYZ\KgiMy²¯~=MHuoy}Wb^`g¯^`dYZiHKMh]^`L?p=^`aKMCa7ZP
EGIHKbXWaK^" MzsY_`MbXbaZig\baqXrb] Zi^ZiHKM#]^`L?p=^`aKMCaZCbausYMCpqMCausYMaZ\V^`d¯ZiHKMHªu«> u©5¦¨©;«©¦¨¥au^" MzsY_`M^`d¯ZiHKMdeobugiMZibL@M HKb]+HbXZ\g\o`auXro"Z\MCs?~WVoWaK^" MCsY_7M^`a
dKaq]Zib^`aqX^`d
(η, β)
o7XZ\HKMkL?MzoaZiHuMkL?MCsKbo`aWMZ\]`GIHKbX "uo`bZ\oZib}`ML?MzoaKbaK_^`dβ
]Coa~=MHKb_7HKb_7H7Z\MCso7X d^7^"X* HKMCa1Z\HKM]^7L?pq^7aKMaZP
bX XrK~uL@bZrZ\MCsZ\^?o`_`baK_uKo`_`baK_@g\oZiM'bXI_7b}7Ma~WV∂h W (t|η, β)
∂t = β(β − 1)
η 2 t
η β−2
o`auso`_`baK_o`]C]MMg+o"Z\b^7a1]o`a0~qM'L?MCo7XrKg\MCs~WV
∂ 2 h W (t|η, β)
∂t 2 = β(β − 1)(β − 2) η 3
t η
β−3
.
GIHWuXCKo`XI#MtXio`bs1~qMd^`g\M`YZ\HKM'MYpq^7aKMaZ\bo`sYbXrZig\b~KYZib^`a
(β = 1)
]o`a~=MtuXiMCs1d^`g L?^YsYMbaK_o?]^7L?pq^7aKMaZ HKb]+HbX#^`aKVXrK~uL@bZrZ\MCs1Zi^@o`]]bsKMaZ\o`udeo`bKg\M`W bcZ\HK^`KZIo`_`baK_g+o"ZiM7E³qo`]MZ\^Oo_7bau_uMaK_7baKMCMg+XhqXruo`V@Zig\V
Z\^?Xi^" sY^" a0o_7baK_@~WV1pKg\M}7MaZib}`M']o`giM?±eXiu]+HZiHqo"ZIZiHKMtMzX[Z\bLoZiMCs
β
g\MLobauXI~=MZ[#MMa¡toaus·7²®a ^`ugX[Z\usYV`#Z\HKM£oy}"obo`~KM0MWp=MgiZ^`pubaKb^`aqXog\MLo`baKV "uo`aZibZ\o"Z\b}7M·oaus _`b}`M0bcZiZiM£baYd^`g\Lo"Zib^`a
o`~q^7YZ
β
¡GIHKbXbXOo¢Xrb_`aKbq]CoaZsYbC=MCgiMCau]M bcZ\H ZiHKM0]^7ausYbZib^`auXgiM"Kbg\MCs¡d^7gbauXrZ\oaq]M~WV TWbaK_`pKugiIoo o`aus TY^`aK_ ±[ 77²Ooaus TWbaK_`puKgiIoo±r6 7² HK^ pKg\^`p=^7XiMCsHKbMCg\o`g\]+Hub]Co#pKgib^`g~uKbsYbaK_7X? bZiH aWKL?Mgi^7uX#HVWp=Mg\puog+oL?MZiMg+XC{^`ZiMkZiHuoZMCgi_7MgIoausTWKa ±[²o7XiXiKL?MCsZiHKMtX\oL?MHWVWpq^`ZiHKMzXrbX#^d opKg\^`L?baKMaZ
pKg\b^`gWaK^" MCsK_`M^`a
β
".Mg\M`y#MXiHuo7XibL?pKVt]^7auXrbsYMCgZiHqo"ZTWKpKp(π(β ))
bX~q^7KausYMzs'd^`gE^`~Yj[Mz]Z\b}7MgiMzo`Xi^`auXC®a0ZiHuMtd^`^" baK_qYMtuXiM'd^`gk]^`aW}7MaKbMau]MZiHKMpqog+oL?MZ\gib¤CoZib^`a
µ = η −β
,·^`g\M'_`MCaKMg+oV7K#MsYMaK^`ZiMθ
Z\HKM@puog+oL?MZ\Mg+X^`dZiHKMOL@^YsYMC¯MzXrp=MC]bo`V HKMa¢MsKM uaKM@^`gkuXiMZiMz]+HKaKb#"KMCXk HKb]+H°]o`a£~qM?opupKbMCs£ba L?^`g\M'_`MCaKMg+o¯XiMZrZ\bau_7X#ZiHqoa0 ¢MCb~uKbaYdMCgiMCau]M7
, Et $%
<3> :" >31>B190; 1"$# " 5G 3 <=<3 >@?4 (>
¡M#o7XiXiKL?MZiHuoZ o`a^`~Kj[MC]Z\b}7MhWaK^" MCsY_7Mh^`d
β
bX oy}"obo`~KM#Xrq]+HtZiHuoZ ZiHKM#pKg\b^7gEsY^7LobaO]o`a~=M~=^`uausYMCsO^`a[β l , β r ] ⊂ (0, ∞)
³K^7^" bau_og\_`KL?MCa7Z+X dg\^`L lgiZi^±r6 7`²7#Mg\_`MCghoaqs1TWKa°±r67²oaus?MzXrp=MC]bo`V#o7]+Huo©'«¬7 ±[ 7²ZiHKbXtbXo0g\MCo7Xr^7auo~KM?o`X\XrKL?pYZ\b^7a Xrbau]M
β
sKbg\MC]Z\X'Z\HKMWbaKMZib]X^d o_`baK_qPka L@Mz]+Huoaub]CoXiVYX[Z\MLXWd^7g pKHWVYXrb]o`¯giMzo`Xi^`auXC
β > 5
bXaKM}7Mg MCXrZibLo"Z\MCs^`agiMzo¯ ¡Mb~KKsKoZ\o0±MK]MpKZ HKMaZiHuMV]^`L?M dg\^`L o";puo`g\o`L@MZiMCg ¡Mb~KKsYbX[Z\gib~KYZ\b^7ao`ausLuXrZ ~qMtg\MCsYq]MCsdgi^7L o@~KKg\aY;baZibL?Mz².;kXrqoV7β
XrZ\oyVYXba
[1, 2.5]
TWMCMmoauaK^"V°oaqs fgi^Y]Co`]]bo¡±``uz²d^`go0MCaK_`baKMCMg\baK_0}WbM p=^`ba7Zz ,·^7giMC^"}`MCgC¯ HKMCa o_`baK_0bX o7XiXiKL?MCs¯Y#M'Huoy}`M']MCo`giVβ l = 1
³K^7^" baK_#o7]+Huo±[6`²WM'pKg\^`p=^7XiMZi^?uXiMo?MZ\o
B e (p, q)
sYbX[Z\gib~KYZ\b^7ad^`gIZiHuMtpKgib^`gI^7aβ
π(β) = Γ(p + q)
Γ(p)Γ(q)
(β − β l ) p−1 (β r − β ) q−1
(β r − β l ) p+q−1
[β l ,β r ] (β)
~=MC]CouXiM'^d bcZ+XI´uMYb~KbbZ[V`;Z]oa~=M]o`b~Kg+o"ZiMzs1baZiMCgiLX ^`dE}"og\boau]Mo`aus0]MaZ\g\o`¯}yo`uMtbausKMp=MausYMCaZiV1^d
(β l , β r )
,£^`g\M^"}`MCgC"l[β]
sYMp=MaqsKX^7aKVO^dp/q
oaus]Coa?~=M]+HK^7XiMa?bausYMp=MaqsYMaZiV@^d og[β]
±eo`aus?XrbL?bog\V d^7gIZiHKM'L?^YsYMt HKb]+HsYMCpqMCausKX ^7aKV^d(p − 1)/(q − 1)
²Io7]+Huo ©#«¬7k±[6 ²pKg\^"}WbsKMCs1o@L?MZ\HK^YsY^`^`_7VZi^]Cob~Kg+o"Z\M
π(β)
HKb]+H0oyVYX ^`aZiHuMXrp=MC]b=]o"Z\b^7a·^doa·^7~uXrMCgi}"oZib^`aβ m
7MaubauXi^`a ±`` `²_`b}`MzXo?giMC}WbMC
^`d ZiHKM0]o`b~Kg+o"Zib^`a L?MZiHK^YsKXO^dko¢#MZ\o°pKg\b^7gOsYbX[Z\gib~KYZ\b^7a bdkXr^7L?M1}"oKMCXO^d
β
]o`a ~qM~KKbZOdg\^`L puo7X[Z MWp=Mg\bL@MCaZ\X@^`g?MYp=MgiZ "7uMCXrZib^`aKbaK_u .^"#M}7MgzXru]+H L?MZ\HK^YsY^`^`_7bMzXg\MLoba «916% ,£^`g\M^"}`MCgCXibau]MMWp=MgiZ\X o`giM'aK^`ZX[Z+o"ZibXrZib]boauXCWZiHKM"KMzX[Z\b^7aKbaK_?Huo`X#Z\^@~=MtbausYbgiMz]ZC
¡MtpKgi^7pq^XrMZ\HKM'd^`^" baK_@L?MZiHu^WsZ\^?^`~YZ+obapKg\b^`g MCXrZibLo"Z\b^7auXI^d
β
4 ~=^`KZ ZiHKM]^`L?pq^7aKMaZP
uo`XiZ\^ZiHuMOMWp=MgiZ\XkZ\HKMOpugi^7~uo~KbbcZ\bMzX
p 0
oaqs
p 1
Zi^1deosY^" a£~=Md^`g\MOZiHKMOZibL?MCX
t 0
o`aus
t 1 > t 0
9g\MCXipqMz]Z\b}7MV`
GIHKMCa
1 − p 1
1 − p 0
= exp (
−µx β 0 x 1
x 0
β
− 1
!)
= (1 − p 0 )
“ x
1 x 0
” β
−1
o`aussKMCsYu]M'ZiHKMtpugib^`gIMCXrZibLo"Z\b^7a
β m = log
log(1 − p 1 ) log(1 − p 0 )
log −1 (x 1 /x 0 ).
±rz²®a¢aKMWZtXrK~qXrMz]Zib^`a=#Md^Y]uX^`Kg'X[Z\usYV0^`a°ZiHKM@pKg\b^7gksYbXrZig\b~KKZib^`a°^`dZiHuM@X\]o`MOpuog+oL?MZ\Mg
η
4 HWVp=Mgipuo`g\o`L?MZiMCg
a
Hub]+H ]Coa ~qM1baZiMCgipugiMZiMCs o7Xo0}WbgiZiqohX\oL?pKM1Xib¤CMbXsYM uauMCs¯· HKMCaKYMCs¯EZ\HKbX}WbgiZiuo`Xib¤CM1 b#~=MuXiMCs!o"d¨ZiMCgiIog+sKX±eba
§
!q7²tZi^¡pKg\^`p=^7XiM1o£]o`b~Kg+o"Z\b^7a L@MZiHK^Ys!^dπ(β )
HKMCa aK^ %§ $¦¬baYd^`g\Lo"Z\b^7ao`~q^7YZIZiHKMtKaq]MgiZ\o`baZ[V^`d
β
bXoy}"obo`~KM7 t¦% 1"¬« 1ªª)©
, <3> :" >31>B190; 1"$# " 5G @1 <0 >B ?4 (>
¶
¼
¶
E
»
K
»@¶
q¶
¼
"!
¡MtMWZiMCausHKMg\MZiHKMo`pKpKg\^7o`]+H^d MCgi_7Mg oaqsTWua ±r67²hN^`ausYbZib^`aqoV?Zi^
β
YZ\HKMV]+HK^W^7XiMd^7gIZiHKMX\]o`M puo`g\o`L?MZiMCgη
ZiHuMt_`MauMg+ob¤CMCsbaW}`MCg\XiMk_oL?LoOsKbXrZig\b~uYZib^`aη|β ∼ GIG(a, b, β)
bZiH·sYMCauXrbZ[V
f (η|a, b, β) = b a β Γ(a)
1 η aβ+1 exp
− b η β
1 [0;+∞[ (η)
±7² HKMCgiM
(a, b, β) > 0
Y bZiH0L?^`L?MaZl
[η k ] = b k/β Γ(a − k/β)
Γ(a) ∀ aβ > k > 0,
o`ausL@^YsYM2,
d [η] = (bβ/aβ + 1) 1/β
EGIHKbXdeoL?bVkbX]^XrMzs~VXi]CoMEZig+oauXrd^`g\Lo"Zib^`a?±b5M`X ∼ GIG(a, b, β) ⇒
∀c > 0
cX ∼ GIG (a, bc β , β)
²' Hub]+H Lo7MCX'bZbaZ\Mg\MCXrZibaK_Zi^·g\MpKg\MCXiMaZtpKg\b^7gtbaYd^7giLoZib^`auX'^7a o0X\]o`M puo`g\o`L?MZiMCgC ,·^7giMC^"}`Mgzbcd Mt]^`auXibsKMgIZiHuMtgiMCpuog+oL?MZ\gib¤CoZib^`aµ = η −β
KM'^7~YZ\o`bapKg\b^7goauspq^X[Z\Mg\b^7gµ|β ∼ G(a, b), µ|β, t n ∼ G a + r, b +
n
X
i=1
t i
! .
GIHWuXZiHKMkpq^X[Z\Mg\b^7g]^7L?pKYZ\oZib^`a£± XrMCM
§
7²bXLo`sYMkMCo7XrbMgz9.^"MC}`Mgz7#MCgi_7Mgoaqs1TWKa°±r67² sK^aK^`ZhpKg\^}WbsYMoL@MzoaKbaK_Zi^Z\HKMhHWVWp=Mg\puog+oL?MZ\Mg+X
a
oausb
GIHKbXE]+HK^`b]Mg\MLo`bauXE]^7aZig\^"}`Mg+Xibo`yXibau]Mπ(µ|β) = π(µ)
GIHKMCa0M'pKg\^`p=^7XiMo`ao`cZ\Mg\auo"Z\b}7Mt]+HK^`b]M7
TWKpupq^XrM°ZiHuoZZ\HKM "uo`a7Z\bcZ+o"Z\b}7M£MYp=MgiZ^`pubaKb^`a ]oa ~qM¢giMCpKgiMzXrMCaZiMCs ~WV o ¥z¦¨§©ªu«¬h ¡Mb~KKtXio`L@puM
˜
x m = (˜ x 1 , . . . , x ˜ m )
mMZπ J (η|β) ∝ η −1
~=MkZ\HKM']^`aqsYbcZ\b^7auo 7M9giMCVYXhpKg\b^`gz;dE^`KgI]^7ausYbZib^`auo`=pugib^`g#^`aη
]Coa~qMtg\MpKg\MCXiMaZ\MCs~WV1ZiHKMtp=^7XrZiMCgib^`g
π J (η|β, x ˜ m )
KM'^7~YZ\o`ba
a = m,
b = b(a, β) =
a
P
i=1
˜ x β i .
GIHWuXZiHKM']+HK^`b]M^d
b
o`XotdKaq]Zib^`a1^dβ
o`pKpqMzog+XZ\^~qMauoZiKg+o5E#MzXrbsYMCXCa
Z\o``MzXZiHuML?MCo`aKbau_^d9Z\HKMXib¤M^`dEoO}bgiZiuo`9X\oL?pKM'VWbMCsYbaK_OZiHKMtX\oL?M'baKd^`g\L?oZib^`ao`XZiHKM'MWp=MgiZ ^`pKbaKb^`a .Mau]M
a
bX#aK^" o'%+«"¬¦§i«©¦21>HWVWpqMCgipqog+oL?MZ\Mg Xrbau]MZiHuM#oyV7MCXibo`aoauo`VYXrZ ]Coa@L?^WsKKoZiM#ZiHuMIXrZig\Mau_ZiH@^dqZiHKMIpKg\b^`gªu«> u©5¦¨©;«©¦¨¥E^`pubaKb^`a
Z\HKgi^7K_`HZ\HKbXXibL?pKMHWVWpqMCpuog+oL?MZ\Mgz#GIHubXkXio`L@puMXib¤MbXo`aMzo`XiVbaZiMCgipKg\MZ+o~KMtpuo`g\o`L@MZiMCgoaus·o_7^W^Ws
d^Y]qXp=^`baZd^7g#oOsYbXi]uXiXib^`a~=MZ[#MMCaZiHuMo`auoVYX[ZIoausZiHKMMYp=MgiZC ¢M'pKg\^`p=^7XiMXi^`L?MksKMdeoucZ]o`b~Kg+o"Z\b^7a
}"oKMzX#d^`g
a
o`aus "7uMCXrZib^7aKbaK_XrK_7_`MzX[Z\b^7auX#ba§
!u[sYMzoV7
π(µ|β)
Huo7Xtoauo"Z\Kg\o` HKbMCg\o`g\]+Hub]CoX[Z\giq]ZiugiM74
XiXiKL?baK_
˜
x m i.i.d. ∼ W(η e , β e )
HKMCgiM(η e , β e )
o`giMpKg\b^7g MCXrZibL?oZib^`auXCY#M_7MZ
b|β ∼ G (a, η e −β ), µ|β, b ∼ G (a, b).
.^"MC}`Mgz9d^`gXibL@pub]bZ[V°g\MCo7Xr^7auXM?pKg\MdMCg'Zi^£]+HK^W^7XiM?o·sYMZ\Mg\L@baKbX[ZMYpKgiMzXiXib^`a°^`d
b
ba¢duau]Z\b^7a¡^`dZ\HKM oy}"obo~KMkpugib^`g XipqMz]bq]oZib^`auXCGIHKbXIbXsK^`aKM'bX#ZiHKMtaKMWZpuog+o_7g\o`pKH
" ->Y ¶ E CK ¶°¶ ¶ y » »
GIHKM·MYpqMCgrZ^`pubaKb^`a bX ªu«> u©5¦¨©;«©¦¨¥? HKMCa HKMZ\oYX?ba Z\Mg\L?X^dkbdMZibL?M` ,°oaWV!oKZiHK^7g\X?ba IoyV7MCXibo`a
bcZiZiMCg\oZiKg\MuXiM@MYpqMCgrZ^`pKbaKb^`auXk^`a°ZiHKM@}"oKMCXk^dhZiHKM@puog+oL?MZiMg}`Mz]Z\^`gO±XrMCM@Io7]+Huo·6`u=mbj[^7b ``^`g
bXiXiM©«¬7h``7²E;ZI]Coa~=MKausYMCg\XrZ\o`ausKo~uMk HKMabcZ ]^7au]MCgiauXZiHKMMYp=^`aKMCaZibo=L@^YsYMCYXibaq]MkZiHKML?MCoa
bcdMZibL?MObXkZiHKM@puog+oL?MZiMgz'KZuXiuo`V0ZiHKM@MYp=MgiZsY^WMzXkau^Z'au^"SZiHKM?X[Z+o"Z\bXrZib]o`L?^YsYMo`aus0ZiHuM@pugib^`g
baYd^`g\Lo"Z\b^7a¡^7a puog+oL?MZ\Mg+X']^`g\g\MCXipq^7ausKX'L?^`g\M?Zi^£o[Zig+oauXrd^`g\Lo"Z\b^7a O^d#ZiHuMMYp=MgiZWaK^" MzsY_`M?~WV£Z\HKM
IoyV`MzXrboaoauo`VYXrZC
GIHWuXC7TWbaKpKKg\#o`oo`aus?TW^`aK_?±[ 77²9Z\HKMaTWbaKpKK_7pKKg\#o`o@±[6 ²]^7auXibsYMCgiMzs'ZiHqo"Zoa@MYp=MgiZEIo`X o~uM
Z\^@XipqMzoo~=^`KZZ\HKMkL?MzsYbo`a1bcdMZibL?M
m = η(log 2) 1/β
* HKMkbXIXrupKpq^XrMzs?Zi^@_`b}`MoaMCXrZibL?oZib^`a^`dZiHuMpugib^`g L?MCo`al[m]
³EbcYbaK_π(β)
WZ\HKMV^7~YZ\o`ba1oO]^7L@puMZiMpugib^`g^`a~=^Z\H1puo`g\o`L@MZiMCg\XC®a1^`Kg#baqsYuXrZig\bo`=]^`aZiMZzZ\^~qML@^7giM_`MauMg+o5Mk]^`aqXrbsYMgZiHuoZoaMWp=MgiZ]Coa_`b}`Mo`aMCXrZibLo"Zib^`a^`do"uoaZibZ[VO]+Hqog+o`]Z\Mg\b¤Cbau_kZ\HKM
+«"§`¦ =«¬"¦+©5§¦ªY©¦21>
M
^d bcdMZibL@MT
bZiH·sYMaqXrbZ[Vm W (t) = Z
IR
Z
IR
f W (t|µ, β)π(µ|β)π(β ) dµdβ.
±7²4
a°baZiMCauXib}7MbZrZ\Mg+o"Z\KgiMsKMCoX bZiH£ZiHKM<"KMzX[Z\b^7aKbaK_^dMWp=MgiZ\XO±eXiMM<oauMCXiHqoH£7>!@d^`gogiMC}WbMC²
TW^7L?MsYbX\]uX\Xrb^`a!ZiMz]+HKaKb#"7uMCX?o`XZiHKM ¦ %©5¦21 L?MZiHu^Ws ±Q'o`grZ\HW#o`bcZ\M ©«"¬7 `` `²tHqoy}`M1~=MMCapugi^7pq^XrMzs
bZiH0Xrq]]MzXiXhZi^@^`~KZ\obadg\^`L MYpqMCgrZ+X "uo`aZibZ\o"Z\b}7MbaYd^`g\Lo"Z\b^7ao~=^`KZZ\HKM'~qMCHuoy}Wb^7g^`doOXrZiqsYbMzsXiVYX[Z\ML0
®a ^7KgO]Co`XiM`Z[^0"KMzX[Z\b^7auXog\MMzXiXiMaZibo3*+N#oa V`^7 _`b}`Mo·g\MpugiMzXrMCa7Z+o"Z\b}7M@}"o`KM
t e
^dIZiHKM1bdMZ\bL?M
T
^`d#]^7L?pq^7aKMaZ
P
xSo`ausr HuoZbXZ\HKMpKg\^`~uo`~KbbZ[Vα
d^`g'Z\HKM]^7L?pq^7aKMaZP
Zi^deo`b~=Md^7giM@Z\bL?Mt e
x
±ZiHKM]^`aZiMZ ^`dE~=^Z\H?"KMzX[Z\b^7auX sYbC=MCg * ZiHuM%ug\XrZ ^`aKM]^`au]Mg\auX§¬¦e«¦¨¬¦¨©oausZiHuMXrMz]^`aqs1^7aKMtsYMCo`XI bZiH
ªY§i«¦¨¬¦¨© $¯XrMCMtd^`gkbauXrZ\o`au]M@moy MCX\X7`² GIHWuX=#MOo`X\XiKL?MtZiHuoZZiHuMOMWp=MgiZk]Coa·~=MOXi^`b]bcZ\MCs0Z\^_`b}`M
obdMZibL?MO}"o`KM
t e
oausZ\HKM */)$%¦ %\«©¦21> ^`d
t e
bcZ\H£g\MCXipqMz]ZZ\^
M
GIHKbXk}yo`uMO]o`a·~qMOpqMCg\]Mb}`Mzs·o`X Z\HKM MzX[Z\bLo"Z\b^7a7I^dEZiHKM
α
^7g\sKMgIpqMCg\]MaZibM`Kauo`L?MVP(T < t e ) = α ∈]0, 1[
$KI^d MYpqMz]Z+o"Zib^`al
[T ]
$uI^dL?^YsYM ,
d [T ]
±eHK^"#M}`MCgC=XrMC}`MCg\o`pKg\b}"o"Z\MsYbXi]uX\Xrb^`auX bcZ\H£g\Mbo`~KbbZ[VXipqMz]bobXrZ\X]^7au]usYMZi^Z\HKM }`Mg\V#MCo`pKgi^7~uo~ubbcZ[VZiHuoZoabausKuX[Z\gibo¯MYpqMCgrZ]CoagiMzoVXipqMz]bdVo@L?^YsYMz²GIHKg\^`u_`H sYbXi]uXiXib^`a Xrp=MC]bcdVWbaK_£pKg\MC]bXiMV£Z\HKMauoZiKg\M^`d o`a MYp=MgiZ^`pKbaKb^`a bXMzXiXiMaZibo50³K^`gObaqX[Z+oau]M`
Xi^`L?MtoYZ\HK^`g+XIHuoy}7Mau^Zib]MzsZiHuoZ ZiHKMtMWp=MgiZ\X ZiMaqs1Z\^_`b}`Mto@L?MCsYboa0}"oKMoZiHu^`K_7H1Z\HKMVKausYMCg\XrZ\o`a7Z
t e
o7X o?L@Mzoa ±TK]+HKbMCgiMCa¢KYmo`aKaK^"V1o`ausfgi^Y]Co`]]bo?7Ky²GIHKMXipqMz]bq]oZib^`a0]o`a~=Mtg\MbaYd^`g+]Mzs1~WVXi^`L?M
^7pqMCa "KMzX[Z\b^7auX o`X
7I HKMa0Z\HKMto_`M'^`d o@_`g\^`up1^d]^7L?pq^7aKMaZ\XIg\MCo7]+HKMCX
t e
K Hub]+HpKg\^`p=^`giZib^`a
1 − α
bX X[Z\bba0uXrMxKI[XIZiHKMt}"o`KM
t e
o?L?MCoa^d puo7X[Z M}7MaZ\XCWZ\o`WbaK_?baZi^o`]C]^`ua7Z MZ\giMCL?M}"o`KMzXI^`gIaK^`Zkx
uI[XIZiHKMt}"o`KM
t e
ZiHKM'deo`bKg\M'ZibL?Mt HKb]+HHuo7XI~qMCMa0^`~uXiMg\}`MzsZ\HKMtL?^7XrZ#dg\M-"KMCaZiV1ba1Z\HKMtpuo`XrZkx
GIHKMCa]^`ausYbZib^`aqoV0Zi^ZiHKM]+Hu^`b]M@^d
a
¯Z\HKM]+HK^`b]M@^db
bX_`b}`MCa¢ba°Z\HKM@d^`^" baK_pKg\^`p=^7XibcZ\b^7a£dg\^`L Z\HKMWaK^" MCsY_7Mk^`dZ\HKMtLog\_`bauo¯sYbXrZig\b~KKZib^`a
M
t¦% 1"¬« 1ªª)©
@`9©
t e ∈ IR +∗
a > 0
« *α ∈]0, 1]
7 1"©b 1 (a, β) =
(1 − α) −1/a − 1 −1
t β e , b 2 (a, β) =
Γ(a)
Γ(1 + 1/β)Γ(a − 1/β) β
t β e , b 3 (a, β) = aβ + 1
β − 1 t β e .
1"©
B i
i = 1, 2, 3
©)#¦ ª)%$./=§¦21§+ 16¬¨¬c¦ >7 1"§I«"¬¨¬ % 1"¦%$81Bπ(β)
+ª)% ©u«"©qª/&/(π(β)) ⊂ [β l , β r ]
(i) P (T ≤ t e |B 1 ) = α, (ii)
[T |B 2 ] = t e
¦
a > β l −1
(iii)
d [T |B 3 ] = t e
¦
β l > 1
7
)§ © ( /)%©®«"©5¦21 °¦t©®«6&
¦¨©·§ :/)$%©©1©) +«"§¦ 9«"¬"¦©§¦ªY©¦21>
M
¦¨© )+¦¨© ! 7" »»
TWMCM 4 pKp=MaqsYbc 4
{^`Zib]M'Z\Huo"ZoaMYp=MgiZ]oa_`b}`ML?^`g\MZ\Huoa0^7aKMXip=MC]bq]Co"Zib^`a³K^`gIbauXrZ\oaq]M`YHuM]oa_`b}`Mto5%§ $¦¦¨¬¦¨©
¦ q©§¥y«¬
[t e1 , t e2 ]
oaus pugi^7~uo~KbbcZ\bMzX(α 1 , α 2 )
Xiu]+H ZiHuoZP (T ≤ t ei ) = α i
d^`g
i = 1, 2
¡M°pKg\^`p=^7XiM Z\^·giMzsYu]Mo`aV°MYpqMCgrZ^7pKbaKb^7a°Z\^ rsKbX\]g\MZ\M ?Xip=MC]bq]Co"Zib^`aqXi = 1, . . . , P
ZiHKMCa¢Z\^£XrMCMz]Z]^`KpKMCX(a i , b i )
³EbauoV7YMXiKL o`Xrp=MC]bq]Co"Z\b^7auXZiHKg\^`K_7H1Z\HKMtpKg\b^7g
µ|β ∼ G
P
X
i=1
P γ i a i ,
P
X
i=1
b i (P γ i a i , β)
!
±!²
HKb]+H1bX#ZiHuMp=^7XrZiMCgib^`gI]^7L?baK_dgi^7L Xiu]]MCX\Xrb}`M#oyV7MCXibo`abaKdMg\Mau]MCX#^`a}bgiZiuo`9X\oL?pKMCXC ¢MCb_7HZ\X
γ i > 0
±Xru]+HZiHqo"Z
P P
i=1 γ i = 1
²Oo`giMKYMCs ba!duau]Z\b^7a ^`dkZ\HKM0giMCoZib}`MZig\uXrZbaZiHKM£Xip=MC]bq]Co"Zib^`aqX moZiMCg@ba Z\HKMogiZib]M`o`a¡o`pKpKb]Co"Z\b^7a¢ bhMYML?pKbcdV ±eo`aus¢]o`gibdVK²ZiHKbX]+HK^7b]M`?;ZbX'g\MbaYd^7g\]MCs¢~V£ZiHKM]^`aW}`MWbZ[VpKg\^`p=MgiZibMCX^dEopKpKb]o"Z\b^7auX
β 7→ b(a, β)
lhXrp=MC]bo`V`WbZopKp=MCo`g\Xh^`~W}Wb^7uXrV@ZiHuoZb 1 (a, β)
±¨Z\HqX#o`aWV?]^`aW}`MXiKL ^`d#XiM}`MCg\o`
b 1 (a, β)
² rL@bL?b]CXOZiHKM?_`MC^`L?MZ\gib]o`~=MHqoy}b^`g'^`dβ 7→ P a
i=1 x ˜ β i
O;ZaKMMzsKX'Xr^7L@M?#Mb_`HZ[V ]Co]Ko"Z\b^7auX'±aK^`Z_`b}`MaHKMCgiMy²h~uYZ]o`aMzo`XibV~=MMa0aWKL?Mg\b]oV1]+HKMC]+7MCs¯®aaKMWZ u_7KgiMzX#MhsYbXrpuoyV'Xr^7L?MhsYMaqXrbZibMCX
m(t)
^`dZ\HKMhpugib^`gL?o`gi_7baqo`sYbXrZig\b~KKZib^`aM
y HKMCgiMt e = 100
[β l , β r ] = [1.1, 5]
(p, q) = (1.5, 1.5)
oaqsa = 2
³Eb_7Kg\M?XiHK^"Xm(t)
HuMat e
bXIXru]C]MzXiXib}7MV]^`aqXrbsYMg\MCs
o7X1Z\HKM¡pKgib^`g0L?MCsKbo`a#yL?MCo`a#yL?^YsYM7*³b_`ugiM !XiHK^"X1ZiHKM M}7^`YZib^`a ^d
m(t)
HKMCat e
bXZ\HKM
α
^`g+sYMgp=Mg+]MCa7Z\bM``d^`ghXiM}7Mg+oW}"oKMCX^d
α
GIHKM]^`g\giMCoZib^`a@~qMZ[MCMa?puo`g\o`L@MZiMCg\X bausYu]MCs@~WVZ\HKM pKg\b^7gL?^YsYMbaK_bX#giMC}`MCo`Mzs~WV?ZiHKM % 1 q¥( YªY¬¨¬7^`dZiHuMpugib^`gIXio`L?pKbaK_$Yba0³Eb_7KgiM K %$ ^dpugib^`gIXrbLuoZiMCs
(η, β)
}"o`KMzX o`giMqXrMzs d^`g@sYMbL?bZibaK_£Z\HKM0]^`aW}7M¢HWK5¢GIHKM1d^`g\L ^`d ZiHKM]^7gig\Mo"Z\b^7a¡g\MLo`bauXaKMCo`gZ\HKMd^7giL ^d Z\HKMZ\HKM^7giMZib]ouj[^`baZ]^7a!qsYMCau]MOog\MCoXiHK^"Mzs0~WV ¡!±```²%$=ZiHuMba}7Mg+XrMsKbXrZig\b~uYZib^`a£^`dpuog+oL?MZiMg}yo`uMCX
HKb]+H!bX?uXiuoV pqMCg\]Mb}`MCs bX]^`HKMCgiMCa7Z@ bcZ\H!Z\HKM·]o`X\Xrb]o`~=MHqoy}b^`g@^ddgiM"7uMaZibX[ZMzX[Z\bLo"Z\b^7auX@^dZ\HKM
puo`g\o`L?MZiMCg\X'±euXrbaK_?KaKWaK^" a0sKoZ\o7²*bcd
β
bXI^"}7Mg\MCXrZibLo"ZiMzsZ\HKMaη
bXIKausYMCgiMzX[Z\bLoZiMCsuoaus]^7aW}`Mg+XiMV`t
m(t)
0 50 100 150 200 250 300
mean mode median
te=100
³Eb_`Kg\M*MCauXibcZ\bMzX
m(t)
^`dEZ\HKMpKg\b^`gLog\_`bauo`sYbXrZig\b~KKZib^`a
M
±bausYMYMCsO~VZiHKMXipqMz]bq]oZib^`aO^dt e = 100
²t
m(t)
x
m(x)
x
m(x)
0 50 100 150 200 250
te=100
10%
25%
33%
50%
66%
75%
90%
³b_`ugiM* kMauXibZibMCX
m(t)
^d ZiHKMpKgib^`gL?o`gi_7baqosYbXrZig\b~KYZib^`a
M
±ebaqsYMYMCsO~WVtZiHuMXrp=MC]bq]Co"Z\b^7a^dα
²eta
beta
0 20 40 60 80 100
0 20 40 60 80 100 120 140
³Eb_7KgiM B*N^`aW}`MHu^`dEo@pKg\b^7gXio`L?pKbaK_@^d puog+oL?MZiMg+X
(η, β)
E #/ '
TW^7L?MoYZ\HK^`g+Xo`XTWbau_`pKKg\IooIoaqsTW^`aK_±r6 `7²q~KubstpKg\b^7g¯L?^WsKMbaK_7X bcZ\HtaWKL?Mg\^`uX¯HWVWp=Mg\puog+oL?MZ\Mg+X
HKb]+Ho^"°Z\^L?^WsKbcdVkZiHKMMYp=MgiZbaKd^`g\L?oZib^`a'bat^Y]oZib^`ao`aus'Kau]MgiZ\obaZ[V`
4
XmbausKMCVo`ausTWbaK_`pKugiIoo
±r6 77²aK^Z\b]MCs¯¯bZtHuo`X~=MMa¡^`~qXrMCgi}7MCs0Z\Huo"Z'MYp=MgiZ\XkZiMCaus£Z\^0pKgi^YsYq]M [^Y]o"Z\b^7a°oaqs°X\]oM@~Kbo7X t®a¢ZiHKbX
#^`g\9^`ug^`pubaKb^`a bXtZ\Huo"ZOZiHKMdu#MYp=MgiZWaK^" MzsY_`MbX_7b}7Ma¡ZiHugi^7K_`H
t e
±eo`aus
α
bcdt e
bXo·p=Mg+]MCaZibM
}"oKMy²{^@^`~Yj[Mz]Z\b}7Mk]g\bZiMg\b^`a1o`^"XZ\HKM'#oyV7MCXibo`aoauo`VYXrZhZ\^OL?^YsYbdVZiHKbX#MYp=MgiZ#WaK^" MCsY_7M` GIHKM^`aKV
p=^7X\Xrb~KbbZ[VbX#Zi^?L?^YsYKo"ZiMZ\HKMtMYp=MgiZIuau]MCgrZ+oba7Z[VZiHKg\^`K_7HZ\HKM]+HK^`b]M^d
a
E®a0^7Kg XrMCauXrM7WZiHKg\MMtXrZiMCpuXI^d ]Cob~Kg+o"Z\b^7aXiHK^`us~qM]^`auXibsYMg\MCs¯7 4 «ªY¬©-%+«"¬c¦§i«©¦21> X[Z\Mp $Yo7]]^7g\sKbaK_Zi^OZiHKMaWKL~=Mg oaqs?ZiHKM'auoZiKg\M^`dXipqMz]bq]oZib^`auXC7#MpKgi^7pq^XrM
Xr^7L@M@sYMdeo`KZk}"oKMCXd^`g
a
GIHKbXkbXsY^7aKMba§
!q7#MCXibsKMCXCq HKMCaa
Hqo`Xk~qMCMa°]+HK^XrMCau#Mpugi^7pq^XrMz t¦% 1"¬« 1ªª)©
ba
§
!u`¢o¡sKMdeoucZL?MZ\HK^Ysd^`g]o`b~Kg+o"Z\baK_π(β)
HKMa aK^ baKd^`g\L?oZib^`a bXoy}"o`bo~KM·o~=^`YZ?Z\HKMKau]MCgrZ+obaZ[V^d
β
K
4 % 1>+#¦ $ %+«"¬c¦§i«©¦21> X[Z\Mp $Y~=MC]CouXiM
a
]Coa1~=M'KausYMCg\XrZi^W^Yso7X#oO}WbgiZiqo9Xio`L@puM'Xrb¤M7WbcZIbXIo@]_7^^Ys puog+oL?MZ\Mgd^7go sKbX\]uX\Xib^7a ~qMZ[MCMa ZiHuM°MYp=MgiZoaqs ZiHKM¡#oyV7MCXibo`a o`auoVYX[Zz ³Ebg+X[Z}yo`uMCX^`da
pKgi^7pq^XrMzs?~WVOZ\HKM'sYMdeo`KcZ ]o`b~Kg+o"Z\b^7a?XrZiMCp]Coa~=MkHKb_`H1 HKMaZ\HKMMYpqMCgrZ#bX}`MCgiV@pKg\MC]bXiM$WZiHuMba7Z\MaZ
bXIZ\^?L?o``MZiHuMtMYpqMCgrZ g\MCo7]ZIZi^HKbX XiMdEg\MC]+WMCX\XraKMzXiX#oaqs]^`g\giMz]Z
a
u 4 =«¬E§%+«¬¦§\«"©5¦21 ·X[Z\Mp $ZiHKMIoyV`MzXrboa£o`auoVYX[Z']oa¢Huoy}`M@Xr^7L?MpKg\b^7gkWaK^" MCsK_`MOo`~q^7YZZiHKM@giMCb
o~KbbZ[V¡^dIZiHKM1MYpqMCgrZ^7pKbaKb^7a 4 HWK_`MbZrZiMCg\oZiKg\MbXsYMzsYb]Co"Z\MCs¢Zi^·Z\HKbXoaqoVWXibX±eXiMMN^W^`7Moaus
Q^^XiXiMaqX7Kd^`go?giMC}bM² GIHKbXkoauo`VYXibX]oa0~=M~uo7XrMzs^`a·^Z\HKMgkXrK~Kj[MC]Z\b}7M~=MbMdeX± Hub]+H£o`giM
aK^ZMYpK^`g\MCs!HKMg\Mz²Ooaqs Z\HKM·]^`L?puo`gibXi^`a bZiH ^`~Yj[Mz]Z\b}7MbausYb]oZi^`g+XC .MCgiM7bcd
a < n
oaqs!bdZ\HKM sKo"Z+ot n
o`giMuau]MCauXr^7giMzs¯ZiHKMp=^7XrZiMCgib^`gOsYbXrZig\b~KYZib^`a bXMCauXiKgiMzs¡Zi^£~=M1L?^7giMsYMCpqMCausYMCa7ZOdgi^7L Z\HKM^`~Yj[Mz]Zib}`M'sKoZ\oOau^" MzsY_`M7®a
§
!qYKoOXibL?bo`gupKpqMCg ~q^7Kaus1d^`ga
bXIsYMuaKMzs1 HKMCaZ\HKMtsKo"Z+ot n
o`giM]MaqXr^7giMzs¯#MzXrbsYMCXC¯Xr^7L?MO~Kb~Kb^7_`g+opKHub]Cog\MCXiKZ\X'og\M_`b}`MCa·Zi^L?^YsYMg+o"Z\MZiHuMOMWp=MgiZ'^`pKbaKb^`auXoaus
ZiHKM]^`auXiMauXiuXI^`dEXiM}`MCg\o`9MYpqMCgrZ^7pKbaKb^7auX#bXX[Z\usYbMCs¯
/5 @;0 <0>B:" > @1:90> :"$#
¶ >`> E"Y » » ¶ z`>¶ EY" ¶ ¶
GIHKbX]Cob~Kg+o"Z\b^7a]Coa0~=MXrMCpuog+o"Z\MCso`]]^`g+sYbaK_Z\^?ZiHKMbaus^dXipqMz]bq]oZib^`a#GIHKMt}"oKMt^d
a
ZiHqo"Z#M'pKgi^`p=^7XiMCsObXZiHKM L?baKbLo`KaWKL~=Mg
a min
^`d=puo7X[Z}WbgrZ\uoKsuo"Z\okZ\Huo"ZhXiMMCL aKMz]MCX\X\og\V'Zi^to`X\XrMzXiXEZ\HKbXXrp=MC]b=]o"Z\b^7a
= ¶
¶
¼
S»
» ¼
¶
4
]^7aYduXib^7a°~=MZ[#MMa¢ZiHu^7XiMOZ\HKg\MMXrp=MC]b=]o"Z\b^7a°bX'MCo7XrV ±eMCXipqMz]boV·Z\HKM
Z[#^@ug+X[Z#^`aKMzX\²GIHKMg\Md^7giMoOsYMdeo`KZ#]+HK^7b]MLqX[Z#~qMsY^`aKM7 ¢M'Xru_`_`MzX[ZhZi^O]+Hu^^XrM
a min = 1
d^7ghZ\HKML@Mzoa o`ausa min = 2
d^7g ZiHKML?MzsYbo`aTWp=MC]bdVWbau_'ZiHKML?^YsYM g\M-"KbgiMzX baZ\KbcZ\b}7MVL?^`g\M puo7X[Z}WbgrZ\uousuo"Z\o±oausOZ\HKM ]MgiZ\obaWaK^" MCsY_7M ^do_7bau_²E ¡MkXiK_`_7MCXrZa min = 3
Xibau]MkbcZ#bXZiHKML?baKbLoqauL~=Mg#^dsKo"Z+otZ\^sYM qaKMZ\HKM L?^YsKo]o7XiXI^`dEo?]^7aZibau^`uX sYbXrZig\b~KKZib^`a ®a·Go`~KM@7K#M_7b}7MkMzX[Z\bLoZib^`auXI^`dZ\HKMtX[Z+oausKo`g\ssYMC}bo"Z\b^7aσ
o`aus0ZiHuM &
*D$
γ
^`dM
qqXrbaK_Z\HKM@pKgib^`g]+HK^`b]MzXsY^7aKMd^7gsKbXipKoyVbaK_1³Eb_`Kg\MCXOo`aus¢Y=qXrbaK_XiM}7Mg+o}"oKMzXI^d
a
GIHKM'L?^YsYMXrp=MC]bq]Co"Z\b^7aopupqMzog+X#o7X#_`b}baK_?HKMzoy}bMgZ\o`bX oaqsdeoy}7^`g\b¤CbaK_OHKb_`HKMCg#}"o`KMzXI^dX
¡MOg\MC]^`L?L?MausZ\^1uXiMZ\HKM@L@MzsYboa°XipqMz]bq]oZib^`a£~WV·sYMdeoKZ'Xibau]MObcZMauXiKg\MCXoog\_`MgKau]MCgrZ+obaZ[V1Z\Huoa
Z\HKMtL?MCoa0XipqMz]bq]oZib^`a
a
σ γ σ γ σ γ
!
" # $"
! !" " !
"% # $ # #"
& %
GEo~KM?*lhXrZibLo"Zib^`aqXI^dX[Z+oausKo`g\ssYM}Wbo"Z\b^7a
σ
oaus0Xi`MC aKMCX\Xγ
^`d sKbXrZig\b~uYZib^`aM
'
2>
¶ ¶ )( `Y
» PkKg@^7giWbaK_£HWVWpq^`ZiHKMzXrbX@bXOZ\Huo"Z@ZiHKM0MWp=MgiZ?Huo`XOpqMCg\]Mb}`Mzs o`X@Lq]+H!puo7X[Z
}WbgrZ\uohsuo"Z\o°o`XtbZObXaKMz]MzXiX\og\V·Zi^°^`~YZ+oba ZiHKMpKgiMz]bXrb^`a
α
HKMa HuM1Xrp=MC]b=]bMCXt e
o7Xo·p=Mg+]MCa7Z\bM`·³u^`g
bauXrZ\oaq]M`=Z\HKM#oyV7MCXibo`a£oauo`VYXrZ]Coa°pugi^7pq^XrM
a = 10
HKMCaα = 10%
GIHKbXbX'XrbL?bogkZi^ZiHKM@aWKL?Mg\^`uX Y¦+©1 §i«>+*L?MZ\HK^YsKXZiHuoZtHuoy}`M@~qMCMa sYMC}`M^`p=MCs£d^`g'Z\HKMo`XibaK_^d#MYpqMCgrZ+X?GIHWuXC oa {^W^`giZ[ bj[ ©«"¬7±r6`²#pKg\^`p=^7XiMZi^1XiM_7L?MaZ
IR +
ba°XiMpuo`g\oZiM'ba7Z\Mg\}"oX=]+HK^W^7XibaK_?~=^`KaqsKog\bMzX aKMzogZ\^giMzo^`~uXiMg\}`MzssKoZ\o
±e^`g]MauXi^`g\MCs?sKoZ\o²TWbaq]MZ\HK^7XiMbcdMZibL?MCX#]oa~=Mg\MpugiMzXrMCa7Z+o"Z\b}7Md^7gZ\HKMMWp=MgiZk±eM}`MCaHKMbXhXiKpKp=^7XiMCs?au^Z
Z\^OWaK^" Z\HKMtsKo"Z+o7²WHKMt]Coa1~=M'o`Xi`MCs1o~=^`YZ HKbX#pKgi^7~uo~ubbcZ[V?^`ddeobugiM7 {MWZ MKoL?pKMbqX[Z\g\oZiMCX^`ug#IoyV
^`dZiHubaKWbaK_u
7 9©
(50, 80, 90, 170)
$ 1>+# /1¦¬ %$ 1"§ $! 1§¥/«"¦¨¬cªY§ O©¦+ D 7 ¦¨¥C¦@©)¬c¦©5¦+##%+«¬?¦
D 1 = [0, 90)
« *D 2 = [90, ∞)
7 9©(n 1 , n 2 )
$?©) uª + $§$ 1B@¥C¦¨§©5ªu«"¬2`«©;«¦D 1
«>
D 2
§ :/)$%©5¦¨¥¬7 qª/&/1 ©K«©I©) ( /)§© ¦¨¥ % u« %$ 1B3§\«&"¦ '31
¡¦
D 1
7 )
n 1 = 2n 2
7
¦¨¥C¦ 1
D 1
¦
D 1,a = [0, 50)
« *D 1,b = [50, 90)
7D *"¦%+«"©O© 11©)# ( /)§©#©u«"©I© #/%©5¦¨¥O¬¦©¦+¦ % 1 q©;«¦ $¢¦
D 1
7 =ª/3/91 ©u«"© ¦ *"¦%+«"© % u« %$?1 §\«&"¦ 31
¦
D 1,b
© 1¢« ¦+@¦¨¬«"§
ª)D©5¦21 1 !«</u«"§©5¦¨©5¦21 1
D 2
D 1,a
1"§
D 1,b
ª/&/1©u«"© ¦Oª =«¬8?© 10«>
§ 73@¦ +ª/&/1 © 1
u«"¥/)§%$¦¨¥$ «©¬8\«©
n 1 = 4
¥C¦¨§©5ªu«"¬ `«"©®«7"!h¦ =«¬¨¬
) %+«> $ `¦¨¥
n 1 + n 2 = 6
¥z¦¨§©ªu«¬9`«©;«7# ¶ ¼e :> ¸ ¶ K> ¶ )( `Y»
TWKpupq^XrMZ\^£^`~KZ\oba¡dgi^7L o`a MYp=MgiZtZiHKMbaZiMCgi}"o`
[t e1 , t e2 ]
oauspKg\^`~qo~KbbZibMCX
(α 1 , α 2 )
Xiu]+H ZiHuoZP (T ≤ t ei ) = α i
d^7g
i = 1, 2
4 sKsKbaK_£Z[^£p=Mg+]MCaZibM1Xip=MC]bq]Co"Zib^`aqX aKMCMCsKXZ\^au^`g\L?o`b¤Ma 1 , a 2
Xiu]+H¢ZiHuoZ
a = γ 1 a 1 + γ 2 a 2
bXZ\HKMLo"YbLo` Xib¤Mo"ZiZ\obauo`~KM@~WV·ZiHuM?XiMpqog+o"ZiM
XipqMz]bq]oZib^`auXCGIHWuXCzXip=MC]bq]Co"Zib^`aqX
(50%, 90%)
b7_`b}`M Z\HKMXio`L?MsYMdeo`KcZEXrb¤Ma = 10
Z\HuoatXipqMz]bq]oZib^`auX(10%, 90%)
,£^`g\M^"}`MCgCCbcdYZ\HKMhpugib^`gEsY^`Loba'd^`gβ
Huo7X~=MMaOMb]bcZ\MCs¯zZ\HKM % 1 )§ *%^`dYZiHKM#]g\M~KbbZ[VbaZiMCgi}"o` bZiHZiHuMt ¢MCb~KuL?^YsYMCLuXrZ~=M]+HKMC]+7MCsqXrbaK_@d^`g\LKo0±[C²;d
β e = log
log(1 − α 2 ) log(1 − α 1 )
log −1 (t e2 /t e1 )
±,`²bX aK^Zba
[β l , β r ]
ZiHKMI^7g\sYMCg\XEXiHK^`KsO~qM L?^YsYbuMCs@Xrq]+HZ\Huo"Zβ e = β 0
±¨d^7g bauXrZ\o`au]M#Z\HKM L?bsKsKMI^`go~=^`KausO^d
[β l , β r ]
²TW^7}WbaK_(
) = β 0
bZiHo'{MCIZi^7aY;nopKHuXi^`a@o_`^7gibZiHKLvbXXibL?pKM±eXiMM #^`uX"KMZh```d^`gsYMZ\o`bX\²
Pkg+sYMg+Xo`giM#Mb_`HZiMzs' bcZ\HtZiHuM]^7auXrZ\oaZ]^`aW}`MCgi_7Mau]M g\oZiM
γ 1 /(1−γ 1 )
GIHWuXCzbdγ 1 − → 1
α 1
g\MLobauXXrZ\o`~KM`
>=» `%$ ¶ 9 ¶ ¶ ¼e :>e ¸
α
&'(*)+
0 < α 0 1 < α 0 2 < 1
,.-/α 0 = (α 0 1 , α 0 2 )
'10) -2 +)` 0 = (x e,2 /x e,1 ) β 0
3`(α) = log(1 − α 2 ) log(1 − α 1 )
,.-/54762*28
)
,:9;
)
4<8<.2.-
ε
'>= <@?0 < ρ 1
'AB'C+)
9
k = 0, ...K
DE
42@F9G +)H+
6
):I)
4 +
2;
δ k =
(1 − α k 1 ) log(1 − α k 1 ) (`(α k ) − ` 0 ) /`(α k )
−(1 − α k 2 ) log(1 − α k 1 ) (`(α k ) − ` 0 )
JE
42@F9G
+)
h k = − (1 − α k 1 )
(1 − α k 2 )`(α k )
'
E
42@F9G
+)
α k+1 =
α k 1 − ρh k (α k 2 − α k 1 ), α k 2 − ρh k (α k 2 − α k 1 ) 1−γ γ 1
1
E 8 +
29LK*6
) -
kδ k k ≤ ε
KNM 11
β 0 = 3
«>(t e,1 , t e,2 ) = (200, 300)
7O!h¦1(7¦(α 0 1 , α 0 2 ) = (0.05, 0.95)
1©®«"¦β e ' 10.03
7 ( /)§©(1 /=¦ u¦21> ·¦ ª)%k« ª u§\«¬¦©¦% /u«"§\«+ ©§ u«/)67 «ªY¬©9(
γ = (1/2, 1/2)
7
)1©;«¦
α = (0.3, 0.7)
7 #% 11 1α 0 1 = 0.25
)1©®«"¦β e ' 5.78
7 )@¦ ª)%$« `¦§ +«"¦ 'ª u§\«1 =«¬867 ¦¨©' ªu«"¬
¦ W©
2 *
α = (0.4, 0.8)
7 $ª +O¦ #+Oª)% + 1"§ %§¦¦¨¬c¦¨©¦© ¬1
§ 1"ª *
9(
γ = (0.95, 0.05)
7α = (0.26, 0.64)
7PM.1 q¥§$ ¬ ¦¨©γ = (0.05, 0.95)
1©®«"¦
α = (0.55, 0.93)
y t¦% 1"¬« 1ªª)©
¶ >`> E"Y » » ¶ ¶ EY" ¶ ¶
Pkau]M
a
Hqo`X~qMCMa0]+HK^7XiMabcZ]Coa1~=MuXrMzsZ\^@]Cob~Kg+o"Z\Mπ(β)
bcdaK^Og\MCo`qbaYd^7giLo"Z\b^7ao`~q^7YZZ\HKMKau]MCgrZ+obaZ[V^`d
β
bXkoy}"obo~KM`[sKMCoV`9Xrbau]MOM@XrMCMπ(η|β )
o`Xog\MdMg\Maq]Mp=^7XrZiMCgib^`gsYMauXibZ[V bZiH¢giMzXrp=MC]ZZi^}WbgiZiuo`sKoZ\o
˜
x a
π(β)
XiHK^`Ks~qM]+HK^XrMCao7Xπ J (β| ˜ x a ) ∝ β a−1 a
Q
i=1
˜ x i
β
a
P
j=1
˜ x β j
! a ,
±7² bZiH
π J (β )
ZiHKM@aK^7aKbaKd^`g\L?oZib}`Mg\MdMCgiMCau]MpKgib^`gzk#Mz]oqXrMtZ\HKbXkpugib^`gsYbXrZig\b~KYZib^`a°bXkaK^ZkZig+o`]Z\o~uM±bZkbX#M9au^" aZiHqo"ZIZiHKMt ¡Mb~KKsYbX[Z\gib~KYZ\b^7asK^MzX#aK^Zo`sKL@bZoaWV]^7aZibau^`uXI]^7a"j[K_o"ZiM7Y]d[hTW^7o`aus£`²
#MkLo7sYMtoa0og\~KbcZ\g\o`giV?]+HK^7b]Mk^`d
π(β )
h#YZIZiHKMt#MZ+o@pKgib^`gπ(β|p, q)
]o`a~=M'Mb]bcZ\MCso`XZiHKMtL?baKbL@b¤MCgI^d Z\HKMtgiMCoZib}`MMaZig\^`pWVZ β r
β l
π J (β | ˜ x a ) log π J (β | ˜ x a )
π(β|p, q) dβ
±`²KaqsYMg@o·]^`aqX[Z\g\o`baZ^`a Z\HKML?MCo`a ^`gtZ\HKM1L?^YsYM7E Hub]+H bXtZig+o`]Z\o`~KM1uXrbaK_ ±rz² .^"MC}`MCgC¯Z\HKM1}"o`KMzXt^d
Z\HKM1}WbgrZ\uo#Xio`L@puM
˜
x a
giMCL?o`ba uaKWaK^" a£GIHKMCgiMd^`g\MM1pKgi^7pq^XrM?Z\^¢X\oL?pKM}WbgiZiqoX\oL?pKMCXdgi^7L Z\HKMW(η e , β e )
sYbX[Z\gib~KYZ\b^7a HKMg\Mη e
o`aus
β e
o`giM pKg\b^`gMzX[Z\bLo"Z\b^7auXCEGIHWuXhMg\Mpuo7]M
π J (β| ˜ x a )
ba°±²~WVZ\HKM ( / $%©$/91©§¦21§/=§¦21§π J a (β) = Z
IR a +
π J (β | ˜ x a )
a
Y
i=1
f W (˜ x i |η e , β e ) d˜ x 1 . . . d˜ x a .
GIHKMCa0L@baKbL?b¤CbaK_·±²#ba
(p, q)
bX XibL?bo`gIZi^L?baubL?b¤Mlog Γ(p)Γ(q)
Γ(p + q) + (p + q) log(β r − β l ) − (p + q)
llog β r − β β − β l
± 7²
HKMCgiMZ\HKMtL?MCoal
[.]
bXI bZiH0g\MCXipqMz]ZIZi^π J a (β)
HuMaZiHKMtpugib^`gIL?MCo`a¡±e^`g L?^YsYMz²#^`dπ(β)
bX ]+Hu^7XiMaWZ\HKM Xi^`YZib^`a?bXKaKb#"KM` GIHKbXL?baKbL?b¤CoZib^`a]o`a@~=MsY^7aKM uXibau_ ,·^`aZiMkN#o`gi^'MCXrZibLo"Zib^`aqX ^d9ZiHKM MWZig\ML?M gib_`HZZ\Mg\L ^d± `²®a^`KgIopKpub]oZib^`auXCZiHKbX#L@baKbL?b¤zo"Zib^`a_7oy}7MpKg\^`L?bXibaK_g\MCXiKZ\XC #YZIbZ#aKMCMCsKX#L?^`g\M#^`g\@Zi^
MCauXrugiMZiHuoZZiHKM ½'K~uo`]+®mMb~KMg pKg\^j[Mz]Zib^`a@sY^WMCXEaK^`ZMzo`stZ\^toa@^"}`Mg+XrZibL?oZib^`a^`dqZ\HKMIpKg\b^7gEbaYd^7giLo"Z\b^7a
, /@1193> :"%# @# "$#0 /#3&;3
# » Y ¶ ¶ ¼ » ¶ ` ¶E»Wº >¶ ¼ =¶
®a Z\HKbXOXiK~uXiMC]Zib^`a #M1_7b}7MZiHKMsYM qaKbcZ\b^7a ^do`a bausYb]o"Z\^`g
˜
n
Hub]+H L?Mzo`XiKgiMzXtZ\HKM1M=Mz]Zib}`MXrb¤M^d Z\HKM oy}"obo~KMk]MauXi^`g\MCssKoZ\ot n
GIHKM}WbgiZiqo¯Xrb¤Ma
XrHu^`Ks~=M']^`L?puo`giMzs?Zi^˜
n
Zi^@^W]Co"Z\MZiHuMXiK~Yj[Mz]Zib}`MbaYd^`giLo"Z\b^7a£ bZiH°g\MCXip=MC]ZkZi^1ZiHKMO^`~Yj[Mz]Zib}`M@sKo"Z+obaYd^`g\Lo"Z\b^7a
4
XrbL?bogbaqsYb]Co"Z\^`gk]Coa£~=M@MCo`XibV0sYM qaKMCs£d^`g
^`ZiHKMCg L@^YsYMCX#Z\HuoaZ\HKMt ¢MCb~uKsYbXrZig\b~KYZib^`a
kMaK^`ZiM
x m
oai . i . d .
¡Mb~KK¯Xio`L@puMk^dXib¤CMm
VWbMCsYbaK_ZiHKMXio`L@MsKo"Z+obaYd^`g\Lo"Z\b^7a^dt n
³K^7giLoV`sYMCaK^Z\bau_
D J c ,J ( t n , x m ) = Z
Θ
π c J (θ| t n ) log π c J (θ| t n )
π J (θ| x m ) dθ
±²Z\HKMk½'K~uo`]+®mMb~KMgsYb}`MCgi_7Mau]M ~qMZ[MCMaZ[#^g\MdMCgiMCau]M p=^7XrZiMCgib^`ghsKbXrZig\b~uYZib^`auXCMsYM uauM^`KgbaqsYb]Co"Z\^`g
^`dM9MC]Zib}`MXib¤CM'~V
˜
n = arg min
m
l
X m D J c ,J ( t n , x m ).
±[z7²³ugi^7L mba ©t«"¬87 ±7`ufg\^`p¢z²ZiHuMMYbX[Z\Mau]Moaus¡KaKb]bZ[V¡^d
˜
n
bXMaqXrKg\MCs®a ±²π J
oausπ J c
o`giMaK^7aKbaYd^`g\Lo"Zib}`M'pKg\b^`g+X bcZ\H·_`^W^YsdgiM"7uMaZibX[Z]^"}`MCg\o`_`M^d ZiHKMpq^X[Z\Mg\b^7g#oyV7MCXIbaZiMg\}"oXId^`g
x m
oaust n
g\MCXipqMz]Z\b}7MV` ®ausYb]o"Z\^`g
˜
n
bX?^d'ba7Z\Mg\MCXrZXrbau]M0bZbL?pKg\^"}`MzXZ\HKM£]^7auXiMg\}yoZib}`M0]+HK^`b]Mr
±ZiHKM·aWKLO~qMCg^dKaq]MaqXr^7giMzssKoZ\o²# HKb]+H·uausYMg\MCXrZibLo"Z\MCX#ZiHuMM9MC]Zib}`MsKoZ\o?baYd^`g\Lo"Zib^`alhXipqMz]boV7u HKMCa£ooy}"obo`~KM
sKoZ\o?og\M']MaqXr^7giMzs¢±
r = 0
²M'Huoy}7M˜
n > 0
PdE]^7Kg+XrM7 HuMat n
bXIKaq]MaqXr^7giMzs¯YM'Huoy}7M˜ n = n
;Xiuo`V
π J
oausπ J c
o`giMX\obs % 1"¥§i« +«"©% W¦ '/9§¦21"§$ $hXiMM o"ZiZ\o ±r677²'o`aus QHK^7X\ok±[6²kd^`g g\M}WbMXho`auspKg\MC]bXib^`auXCEGIHuMksYMuaKbZib^`ad^7^"X* sYMCaK^Z\baK_θ n (α)
ZiHuMkp=^7XrZiMCgib^`gα−
"uo`a7Z\bM^`dθ
~uo`XiMCs^`a^7~uXrMCgi}"oZib^`auX
t n
±b5M`P c J (θ ≤ θ n (α)| t n ) = α
²qbcZL?MCo`auX#ZiHqo"ZP θ (θ ≤ θ n (α)) = P c J (θ ≤ θ n (α)| t n ) + O(n −i/2 )
HKMCgiMZiHKMkMd¨Zr;Huoaqs1XibsYMkbXhZiHuMdg\M-"KMCa7Z\bXrZpugi^7~uo~KbbcZ[V77 HKMCgiM
θ
bX.uWMzsbaΘ
oausθ n (α)
bXg+oaqsY^`L0Woausi
bX±ebsYMzoVK²Z\HKMtHKb_`HKMzX[ZoZrZ\o`baqo~KM'}yo`uM±¨ZiHuM]^"}`MCg\o`_`Mk^`g+sYMg²®a0^`ugopKpKb]o"Z\b^7auXCπ J
Io`X ]+Hu^7XiMa0o`X Z\HKM§ § *%./9§¦21"§±e#MCgi_7Mgoaqs@#MCgiauo`g\sK^@`² HKb]+HbXoZhMzo`XrZ^d9^`g+sYMg Z[#^o`]C]^7g\sYbaK_kZi^OTYKa£±[²TWbau]M
t n
bX']MaqXr^7giMzs¯q#M?]+HK^7XiMπ J c
o`XkZiHuM@XipqMz]bo 7M9giMCVWXpKg\b^`gO±ebaq]usYbaK_·]MaqXr^7giMzs0ZibL?MCX+² Hub]+H¡]oa~=MsYMCgib}`Mzs1dg\^`L kMOTYoaZ\bX3©«"¬7±``Ky²#GIHKMoKZiHK^7g\XXiHK^" bcZkHuo`X~qMZrZiMCgp=^7XrZiMCgib^`g]^"}`Mg+o_7MZ\Huoa0Z\HKM
XrZ\o`ausKog+s `M=g\MVYXIpKg\b^`gz#³ugi^7L#^`uX"KMZ±57`K9NHuopYZ\Mg ²qbcZbXsKM uaKMzs·o`XId^7^"XCu HKMCa
t n
]^7a7Z+obauXn − r
gib_`HZi;]MauXi^`g\MCs)uWMzs1}"o`KMzXc 1 , . . . , c n−r
9©
γ
$1©) ªY¬8§ % 1 )©;«> u©γ ' 0.57722
7 ©γ 1 = π 2 /6 + γ 2 − 2γ > 0
«>γ 2 = −2(1 − γ)
71"©
˜ δ(µ, β) = δ 2 (µ, β) + [δ(µ, β) − 1] γ 1 + γ 2 log µ + log 2 µ
+ π 2 /6 − 1, δ(µ, β) = n −
n−r
X
i=1
exp(−µc β i ).
°© */ $%¦e«"¬ § /=§¦21§ 1"§t© ¦ªY¬¨¬!/K«§i«+ ©5§¦z«"©5¦21
(µ, β)
¦π c J (µ, β) ∝ (µβ) −1
q δ(µ, β). ˜
"¶ " ¶ :>¶·» y¼ ¶ " » z ¶ »
TWupKpq^XrM#Z\Huo"Z ZiHuMsYbX\]qXiXib^7a~=MZ[#MMCaZ\HKMIMYpqMCgrZo`ausZ\HKM oauo`VYXrZ]oL?MZi^toa?o_7giMCML?MaZ o~=^`YZ ZiHuM ^`g+sYMg
α
^`d#op=Mg+]MaZ\bM?}yo`uMt e
?GIHuMabausKMp=MausYMCaZiV£dg\^`L Z\HKMMYp=MgiZC¯Z\HKMoauo`VYXrZ']Coa ]^7gig\MC]ZkZ\HKbX^`g+sYMg
uXibaK_1Z\HKMg\MCXiKcZ+X'oy}`Mg+o_7MCs0~WV·aWKL?Mg\^`uX'o`YZiHK^7g\X'o`~q^7YZkZ\HKMg\MCoXiMauXiM@^dhZ\HKM?pqMCg\]MaZibMOpKg\b^`g'MCXrZibLo"
Z\b^7auXI³uo7]MtZ\^ZiHuMgiMzXrucZ+X ^d}"og\b^7uX MWp=Mg\bL@MCaZ\X ba·giMCbo~ubbcZ[V7KZ\HK^7XiMMCXrZibLo"Z\b^7auXog\Mt_`b}`MCa·]g\MCsYb~KbbZ[V
^7g\sYMCg\XZ\Huo"ZuXiuo`V1og\M'}`MCgiV^"}7Mg\MCXrZibL?oZiMzs¯®uX[Z\g\oZiMzs1~WV ,£MV`MCg oaus0#^W^``MCg±r6 ²#o`ausmoaKau^"V1oaus
fg\^Y]o7]]bo ±5`uz²o£Z+o`]bZ?giKMbX@XruL@Lo`gib¤Mzs ba!aKMZ@Z\o`~KM`L?^YsYbdVbaK_¢ZiHKM0^7g\sYMCg^`dpqMCg\]MaZibM1Z\HKMa
_7b}WbaK_?uXIKpKp=Mg~=^`uausKX
a ∗
d^`ga
6! t¦% 1"¬« 1ªª)©
% %
a ∗
"
!
Go`~KMt*Go7]bZgiMzsYu]Z\b^7a^`dEp=Mg+]MCaZibM'^`g+sYMCg#~=MZ[#MMCa0MYpqMCgrZ ^7pKbaub^7ao`aus1g\MCo`bZ[V`
# » ¶ -E ¶ º¶W¶ ¶ ¶ zz
HKMCa1pKg\b^`g+X
π 1 (θ), . . . , π M (θ)
o`giMkL?^WsKMbaK_?XrMC}`Mg+o=oy}"obo`~KMO±bausYMp=MaqsYMaZ+²MWp=MgiZI^`pKbaKb^`auXC`Z\HKM % 1¥ (
¦ Y©$ %1>+#¦ =«©¦21>
π(θ) =
M
Q
i=1
π $ i i (θ) Z
Θ M
Y
i=1
π ϕ i i (θ) dθ ,
HKMCgiM
P M
i=1 ϕ i = 1
YL@baKbL?b¤CMCXIZ\HKM½'K~uo7]+;mMb~KMCgbaYd^7giLo"Z\b^7a^7X\XKL(π; π 1 , . . . , π M |β) =
M
X
i=1
$ i
Z
IR
π(θ) log π(θ) π i (θ) dθ
o`aus0]og\g\bMzXI^`YZo`a·^`pYZ\bLo %1> ª^`dZ\HKM^`pubaKb^`aqXITWMMmbbXr~=Mg\_£±[uz²^` 4 Ziug\o`¤¤Co © «"¬7t±57>!²
d^7gL?^7giMOpKgiMz]bXrb^`aqXko`~q^7YZkZ\HKbX'Mb]bcZ+o"Zib^`aGIHKMOg\Mo"Z\b}7MbL?pq^7grZ+oau]MO^`dZiHKM?MWp=MgiZ\XbXj[usY_`Mzs·Z\HKgi^7K_`H
Z\HKMt]+HK^`b]MzXI^d#Mb_`HZ+X
$ i
N^^7`M ©I«"¬7k±[ 7²h^`g#usYMzXi]oaqsnoaZibo±7`²ho`L@^7aK_@^ZiHuMg+XIpKgi^7pq^XrM
XiM}7Mg+o9]g\bcZ\Mg\boub`MkZiHKM'puo7X[Z Mg\g\^`ghg+o"Z\M`WZ\^<K1ZiHKM'#Mb_`HZ\XZiHugi^7K_`HL@MZiHK^YsY^7^7_`bMCX HK^7XiML@^X[ZIdeo`L@^7uX
bXIpKg\^`~uo`~KVZiHKMkMpKHKbL?MZiHK^Ys ±eXiMMtmbauXrZi^7aKMoausGKgi^¢77d^`go@giMC}WbMC²³K^7grZ\KauoZiMV#Mt^`~YZ+oba
µ|β ∼ G
M
X
i=1
$ i a i ,
M
X
i=1
$ i b i (a i , β)
! ,
β ∼ B e M
X
i=1
$ i p i ,
M
X
i=1
$ i q i
!
HKMCa
π i (β)
bXIoO#MZ\o@sYMauXibZ[VB e (p i , q i )
sYMuaKMzs1^7a1oO]^`L?L?^`asY^`Loba[β l , β r ]
GIHKMt]^7auXiMauXiuX#sYbXrZig\b~KYZ\b^7a^7a
µ
o`pKpqMzog+X o`X#Z\HKMp=^7XrZiMg\b^`g sYbX[Z\gib~KYZ\b^7a0]^`L?baK_?dgi^7Lo?]^7auXiMauXiuXI}WbgiZiqoX\oL?pKM' HK^7XiMXrb¤M'bX Z\HKMk#Mb_`HZ\MCsXiKL ^do`9Xib¤CMCXCE;dMYpqMCgrZ+X]Coaau^ZI~qM]^`aqXrbsYMg\MCs1o`XbausKMp=MausYMCaZ'±euXrqoV? HKMCaM > 2
²]^`g\giMCoZib^`auXILOuX[Zk~qMo7sKsZi^ZiHKML?^YsYMCbau_u ³uo7]MtZ\^ZiHKbXbX\XrKM79P .o`_7oa ±``Kq``7²#_`b}`MzXIauL@MCgi^7uX
o`gi_7KL?MaZ\XZi^OsKM uaKM'o]^`auXiMaqXruX±~WVsYbXi]uX\Xrb^`aL?MzoauX+²~=Md^7giMZiHKML?^YsYMbaK_q #YZI#M^`~KZ\obaZ\HKMX\oL?M
Wbaus^dpugib^`g L?^YsYMbaK_q
¯EIE #$ 0t
#Mg\_`MCgOo`aus TYKa ±r67²pKgi^"}WbsYMCsX[Z\MpuX@^`dQb~u~uXXio`L?pKbaK_¢ HKMa