Web Metasearch: Rank vs. Score Based
Rank Aggregation Methods
M. Elena Renda
Umberto Straccia
I.S.T.I. – CNR
Area della Ricerca del CNR
Via G.Moruzzi 1, 56124 Pisa - ITALY
I.S.T.I. – CNR
Area della Ricerca del CNR
Via G.Moruzzi 1, 56124 Pisa - ITALY
[email protected]
[email protected]
ABSTRACT
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Categories and Subject Descriptors
n = o= o9p qr,set@u8v$wAxcqt@rzy;xt@u8w@{,|Ow8r,}/u8|xcu8q|:~w8>€]
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Keywords
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@L‚B#)< RYD+ ?P+( 3 & ))=
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SAC2003, Melbourne, Florida, USA
Copyright 2003 ACM 1-58113-624-2/03/03 ... 5.00.
ª
1. INTRODUCTION
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3.2 Experimental setup
d"Ba)E8f) A¸G+ a;#" )B6
EBW W#( ( F1N=8:+!f & )D W && ( FEXQ?Aƒj
?Aƒj c?Aƒj ½0;E
?Aƒj2¦§§ Ä ;EB EB";( ( 3D=UØF+
?AƒjcF+5E< & D XFR Ä § ( =l:+
(W & #)FEU#( ( F1N]S;EB)( 3
( +R-
@«
&)¦ *  * © * *FÄ § *FÄ ¦ / Q( .1@= F= F=G% !?AƒjcG && ( 3
8#" !)EB;EX+EX9F & + a
#"FE98( .=:?A af & )De :EB FE8W+) & <
‡ ×DÔ3Ô RS.ÍÍÔËDÑÈPƁÖÐÒ<ÔaÆMÌÊÓ
L‚;EBFEG< e)3W; && @;<aN+D;EBZ"') FE@EB ¸GD
"=:?Ah1A@+ EBN@'[.2"Q# F=
?AW( .cL‚¼k;Eh cF & + !<@F1N>=
#" h)EB=:?A#" h)EB;<A1N ( (>'[c.FEh<
e , , a@1N ,+.Dc
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;F,( D( 3)EB \;FEX9 )«'D3!") ;<8F+!FE
)m`¶ h 2FE H†_†‚H‡2;XD3Q"BFEQ ) >=
3.3 Experimental results
A? 9"( @A"B@f & )DW<, & FE! O?Z'( ÄUT B=
Ø:F+%)EG<A( "a ,F1$ ;EB +F<e8Š‰H‡ŠFJDH
¹;‡H–ˆ#ˆ•9G Ä § ( #AF+" & =:j+ @N( B6
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e , , a[[8#( ( F1N +FX'[W.'( FEG]
Ä =A1@= F= F=N)EB:';FE%%N)EBa1N +
EBNZ+"D>: ^ e , f , § * e , hc, §` & #)/'[P;
:+"D N ^ e , f , +Ä * e , hc, Ä `=:?Aa"( Z Z"B & .6
B, , ,'[( FE-;<,+"D R 93B ( EB,'[
& #)+b
[
Y*Y*[*v
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\ YDwguD|
\ YD|gY*v
\ Y*[*v*v
\ Y*[Dwg{
o[Z %
o[Z 1
o[Z x
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cd eUd X
cd eUd |
cd fd X
cd fd |
cd g8d X
cd g8d |
cd id X
cd id |
w
Y*t:X*X
\ Y*s*s:X
\ Y*u*vDw
\ Y*s*[*t
\ YDwgv*s
\ Y*u*v:X
\ Y*s*tDw
\ Y*s:XIu
\ Y*u*u*v
\ Y*u*s*{
\ YDw*w*|
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\
k
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XIt*Y*v
\ XIu*{
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\ XIu*Y*Y
\ XIs*s*[
\ XIu*[*{
\ XIsD|hX
o[Z %
o[Z 1
o[Z x
o[Z y
cd eUd X
cd eUd |
cd fd X
cd fd |
cd g8d X
cd g8d |
cd id X
cd id |
w
XIs*{*t
\ XIv*Y*{
\ XIv*Y*u
\ XI{*{*Y
\ XIu*t:X
\ XIsDw*w
\ XIt*Y
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\ XIv*s:X
\ XIY*t*u
\ XIY*v*Y
\
k
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[*{*t*{
\ [Dwg{:X
\ [Dwgs*Y
\ [*s*v*Y
\ [*u:XI[
\ [*s*[Dw
\ [*s*v:X
\ [*t:XRw
\ [DwhXRw
\ [*sDwgt
\ [*v*u*v
\ [*u*[*[
o[Z %
o[Z 1
o[Z x
o[Z y
cd eUd X
cd eUd |
cd fd X
cd fd |
cd g8d X
cd g8d |
cd id X
cd id |
\
k
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mln jws
mln jzys
k
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XR|
Y*v*t*[
\ Y*v*u*v
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\ YDwgY*{
\
XI[
Y*{D|gu
\ Y*{D|gu
\ Y*v:X
\ Y*{*{Dw
\ Y*uD|*w
\ Y*s*[*u
\ Y*{DwgY
\ w*|g[*v
\ Y*s*t
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\ YDwguDw
\
VXWLY
] -^+_L`
] -^ 8`
] 3a-`+_
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] -`8h3b
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XIvDwg{
\ XIv*v*t
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\ XIuDwgY
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\ XI{*t*u
\ XI{Dwgt
\ XI{*uD|
\ XIY:XIv
\ XRwhXI[
v
XI{D|gt
\ XI{Dwgs
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\ [D|*|gt
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\
XR|
IX {*sD|
\ [D|gYDw
\ XI{*t*{
\ [D|gvD|
\ XRwgv*v
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\ XI[*{*{
\ XI[*{Dw
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XI[
IX {*t
\ [D|gt*[
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] +b-`
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W F\
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Wh\BZ
Wh\ BZ
ŽonqpsxCn t jXhco l&jDkqmin Ž jDpun qp3v
w
YD|*wgu
\ [*vDwgt
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\ YD|gsDw
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v
Y*v*uD|
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\ Y*t*s
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\ Y*{Dwgv
\ Y*sDwgY
\ Y*u*t:X
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ŽonqpsrCn t jXhco l&jDkqmin Ž jDpun qp3v
mln jCmis
k
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\
s
:Y XI[
\ Y:XIs*v
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\ Y:XIv*{
\ [*t*{:X
\ [*t*v*s
\ [*{:XIY
\ [*{*u*[
\
v
Y:XIv*u
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\ Y*[*s*u
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\
XR|
Y*[*v*Y
\ Y*[*s*v
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\ Y*YD|gY
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\ Y*Y*Y*[
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XI[
Y*YD|*w
\ Y*YD|*w
\ Y*[*t*{
\ Y*[*v*t
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\ YD|*wg[
\ YDwgt:X
\ YDwg[*u
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VXWLY
8`
3j8_-b
8h-^3^
8`
8b8_3_
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8`
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3^8j-`
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\–W F\
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] Z >Z>Z
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]
]
Žonqpsx{|n t jXhco l&jDkqmin Ž jDpun qp3v
¦D=A1@= F= F=F:)EBG';FE@8+: PN"'.B6
(EB ¸G+'[‚1A@:)EB>1N +9EBc+"DP
[
[*t*[Dw
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\ [*t*{*s
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\ [*t*{*{
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\ [*u:XRw
\ [Dwgv*Y
\ [*v*vDw
\ [*u:XIs
o[Z %
o[Z 1
o[Z x
o[Z y
cd eUd X
cd eUd |
cd fd X
cd fd |
cd g8d X
cd g8d |
cd id X
cd id |
w
[*{*sD|
\ Y:XI{Dw
\ YD|g[*{
\ YD|g{*s
\ YD|gY*u
\ Y*[*v*[
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\ Y:XIs:X
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\
mln j_s
k
s
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\ Y*[D|*w
\ Y*[*Y*Y
\
k
Žonqp
v
Y*Y*t*s
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\
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\ Y*[*t*[
\
XI[
YDwgt*v
\ YDwgt*v
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VXWLY
8j
8j-^
+a3b
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8b3a
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3^+_L`
8a3b
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3j3b-`
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\BZ
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]Z
] Z –W
] \–W
]\
]
]
t jXhco l&jDkqmin Ž jDpun qp3v
^e , 8 , Ä+* e , gD, Ä `8;E!1N +-EBX8+"D9 ^ e , 8 , § * e , gD, §`=O?A#+"D R 9)99
) & < & #)+W X)F<+>b
o=2+$)( < & #)+( F<( 30'[;076
+8)( < >b
B=A)( < & #)9'[8; i Eh
)( < 0;EGW & < +"( <F8 & #)X'[
;
i j )EG= ´ ( R i jmF1AFE
S'[
& ) X OF<( 3Of & )D%p Ä €e @1A@1AQ<
( F.c#c)F<+>b
¨D=Ae , 8 , Ä )EGˆMI#HFI KB+)( < X;E+"D6
X P1N 8B%"B82#"B8.Z'"B8 9F
e , 8 , §b
& + R N"'.D ( ( 3hFTD";(G
©=Ad
e , f , §,)EG[ˆMI#HFI K)( < R;EhEB,
+"D G)3X+ EBFER81N %^#1N B
"BW:#"B.`>;ER WF & + .
),';FEh)EBb
ÁD=Ae , 8 , a)EBW1N 8<@e , f , §h)E$^_
a X?Aƒj2¦§§ Ä 3h<83+( <`[ Q)NZ1N ;EQ+( F<( 3X h)2aF & + >=
?Z'( ,¨9+D 2@F & + R<2W#"BN.=
k
o[Z %
\ YD|g[*u
cd fd X
\ YD|hXIt
o[Z 1
\ [*{*s*s
cd fd |
\ YD|gY:X
mln jsjXh.mij
t
o[Z x
\ [*{*[
cd g8d X
\ [*tDwhX
o[Z y
\ [*{*v*v
cd g8d |
\ [*tD|g[
cd eUd
[*t*u*[
X
\ [*s*{*[
X
\
cd id
|
\ [*v*u*t
cd id |
\ [*s*{*Y
cd eUd
h.jDf obpo gk gjXh2q_j–qjDpqp3v
·c'["B29gX<<+; X';FEh)EB1A@'W;<F]
Ä =A Zc+( F<Z1N F= ¾ ;E U <:\.Z‚1N +
;E@ eF & + , Za && + '( 39EB ¸GDFb
¦D=A@gX<<+; h';FEQ)EB1N h<'e , f , §9B
)"B@:#"BFZ;EX,F & + @ ¾
;E <,+( F<( 3!'[;R,:X';FE
+),' ;<U h)EBb
o=AcF & + A ¾ ;Ez U <c+) & <<6
'( W,@ e , 8 , Ä ;E e , 8 , § =
4. CONCLUSIONS
´ N )3%"))< 72"B"( %N+DfP)F<+
A#( ( F1N=2j"D , 2EBD22 ) & <2¸G+ \;+FD( 3D=k·EEB ;( ( 3D21AR;FRF1N5;<FN+D<3
1N;< "";( ( 3!")FEG,<8h';FEX)EB
ˆMI#HFI KPQgX<<!+; -';FEO)EBP1N & #)+
+) & <'( hO+R';FE$)EB=5?A & + ( ( 3
) & D: %2+Df:>)F<+:+A<N"";( ( 3
QF ( '( X )CXF<+
=ULM %1A
;<@gX<<!+; ';FE)EB@EBh@( 3!O '"BcEB,( 3Qh+) & < N( 3D=
?AQ<Q)QEB + 9#9#"B"BF<+>a1N +-1A
<O+"BD( 3U . < Bbh^_¶‚`$ 351NgX<<
+; ';FE
)EB & #) 1A( (( S Q+Df
HFI JDI KA. -)V( S1@= F= F=AX?Aƒj²"( b^_¶¶‚`,
. < & #)+N)EB@1N- E<, cF ( '( =
5. X REFERENCES
!#" $&%('*)+$, , $&- . $&/#0
5 -6 875:9;5=<?> |hX 'A@$& [*t*s,Bh [*- vD w $&'&1[D|* |hX " 32 /% $& $&/#4 [C ) 6 *D / $ F E % &G / #1/" E " '4 G -3$&1#4,/#1 G - IH;J KL:MNJ OP(QP
YC 7RS TV/#@ U W / aQ3PX D YZ/ J=1G P\-$&"*[!$&h - MN] WNb R $,QcP$&/K_/# 4^-4U VJ=P-d` $&U P - K *XIe t*
v: X $&-$ % a( 2$f" $&/# > #4,$&" +q a g ' ,YDi |~t X > t&uwv XR|g t,>B X*G XIt ' XIj{*MN{*Y_v k*l*L:PO_m_P,L nMNOoNK W `pQ
^*]&$&K" "L:$&P-IYZ'AK x G - b 1I'*$&- /#14 h 63/ 2 7 $&/#4 G -
wN )+^A$&%r;/ ms
3
6
G
7G5:9; 5=G<?i > 1 {*u 'A4 @ $&" " 4 G [: Xw-hB yc[*v ' G XI
{*{*G -u 2 / D -4 - c /#0 5 -6 uC{z/ G #14w0{" 63?2/#$&/ :c % " " '|;" $ $, G (} $&$,/#c4 0 G --'*$&- - (d -$&1~" € e G " c3$ G /# G -
W W ‚W G ' XI,{* {*{ G 5 L  T lKL O WNR J W `
r
sC |; $&" - L 4 G G "I-|;KC_P{/ ,jG $&" MNG /#-`N4 ƒ,
„ /? -$& - G - ?1 " G V-f… % }! $&c $&/#…4 g @ T / G -4 c W G WU
'
' j3†ˆ‡*O `*K L J=MN`*K
q W
tC 6 MN` a$&-- 0{`N
ƒ,$&G MN$f&O&Y|!/ c &L $J=/#MN0*`' -^*< ]&$,% K L:GpPYZ‰ 1K %f32XI$&u/t ' /Y&uwv XI {*- u,Gc Bhz [*[* [$&/-'*XI$&{*~-{*€ t | 7G N$&01%f$&/
<
G ,i 5 L  q `AL:PO` W L J=MN` WNR
$&j- MN `Nƒ, „?MN`ŠG L *-{PŒh ‹Œ MN#"O R aQ' ‹[D|*J=|hQX PŒ‹ŒP ‚ '*@$& s:XIY,Bhs*[*[ 6 d / #
vC <@/ -2 $&/ " -Ž 4 $& G G -(-$&%_- 1" …yG % c3,$&G/ $_b 1 h / G G %f%5 -‘ /# 5 U-4 /#@ /#$ G -\1 /
q `AL:PO` W L J=MN` WNR jMN`Nƒ,„?MN`Šr W L W‚W KCP.‡*PMNOOM ] ' „yb M#z ƒf6 ’&7 L  X*XIv*s ' XI{*{*t
{C ) 1/#4@ Ž*,g ' …y 6c3$&/ .- 7
/#$,$&c 4 6 % /#i$&G 4w-0{$ %fG $ - / 2%_1@ " G / @% " - G g(g G 5
6 8 7v5:9;e 5=
<? > {De w <' … XI{*{D> w [ G G !
XR|N 57 - 1#$ &" -" G 9 - $& 142 1
' G 9 -(1 G2 “ / 1 -(%sh‘%_$&1-" G '@$&" - ' . G $&/ / G G i Z1 9;, % , ” $&/#4 d (/ & Ž -1 G - G - v
" 1% '*@$& '
X*X 7$& /# 4 Vb $,[-c / - -4 $&s*- Y*t,BhbpsD,wg { 6 XI{*9;{*s G " 5 -1 G /#1' z … 6 5 % ' $
G W q
YD|v {*u,B>XR|gu ' XI{*{*v jMNY_k*l*L:PO_m_P,L nMNOoNK `pQ ^Ar;m•^*]&KL:PYZK
XI[C )6 8
- }!7f5:9;bp5=,<? > {*!t 'A-@$&"$&a G [*2s*t,%_Bh1[*t*" s G @' " XI;{*{* t G -4 4 % iG -$ G - 5 XIYC <G / G $&i -1 %fG $ -
32$' </4 < % $ i
G - '*G $&-- Ž – Ž*1 -@ 1 2y " G $&-/#\4 (#4 -/ G - 5 6
'A@$&
'
XRwN | %f98% 77 5:$&/ 9;$&/5=<?G > e |hX
%f$ [*%fs*t,$ Bh' G[*4,t*u$& /#24 [D|*N|hX G - v | % 4,/#$ G 4
a a
U
XIuC 9;q /#$&/ .W 7 $&y" ‡ -(*P\$&-— MN) `pWNMNR YZG J 4 K
L $ G " -{4 h 9; w‹G "#"" [D|*a{q |*`A|d L O1 MNi QN" l U 6 L J= MN`' L:M(†‘MNQPO`
XIsC …/ `Nƒ, 7MN1O Y/#" iA4 /#L $&J=_MN&$&`&- / [!.&P,$™ L OG J= …P- ˜ ”, G - - G
e h _,i q $+63/#$,c" /$&/#4' G XI4 {* v*1Y / 2 /
)+$&-1$&/ a B Ž*,i /#1$&/ a uwv X*Xw>B XRw ' XI{*{*t —3—3—š—›,k*PO,L
t
XItC "6 - / $&G /?4 @ %
/-6 $ *œ - 2$&#4- ./ 9 $&/#/ G -(h 6 N# / " " Ž 1 G ' -{ G $f$
G iG G q `Nƒ,MNOY W L J=MN`[!P,L OJ=P˜ WNR
X+t Y&uwv XIu:Xw>B XIt*Y ' XI{*{*{
XIvC … "
" - 4 " " 4œ G -Z/ 2 ,1 'G -(z $&@/ / &- i " /#$% ‰ 5 -9 | 1@ ‰ $'} $&$&- /# %fD $&-I -(' ,) &G / 'p- > b $ G U / e  OQ‘‡3Pw›+L3[;—3L OJ=P˜ WNR j U MN`Nƒ,POP` U P{ž‡[;—!j3Ÿ  '-1% iA / uD|*| > O[*M [*u „ '
w z $ G -$&" 5 - G 1 V 2 7 $&- $&/ ?$&- 4 - " a
XI{C 2<XI/ {* {D%s
-$&" %_1< " G @¡ " $& 4 /" " $& - 4 G <?- aG i -$&2 " /# %f$ ™ G- -{
/ 2 / 1G G Ne $&- "p a 2 %f4,1% - WNR
T UW U
q W
U U ' ¢MNlO`
XIM#ƒ_Yt L wg*{&P uwv X*XIYt*t,PB>OJ X*XIvD`‘w ' ^pXIM {*{*J=P,v L ]–ƒ,MNO `Nƒ,MNOY L J=MN`^ J=P` P
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