ArticlePDF Available

SISSY: An efficient and automatic algorithm for the analysis of EEG sources based on structured sparsity

Authors:

Abstract and Figures

Over the past decades, a multitude of different brain source imaging algorithms have been developed to identify the neural generators underlying the surface electroencephalography measurements. While most of these techniques focus on determining the source positions, only a small number of recently developed algorithms provides an indication of the spatial extent of the distributed sources. In a recent comparison of brain source imaging approaches, the VB-SCCD algorithm has been shown to be one of the most promising algorithms among these methods. However, this technique suffers from several problems: it leads to amplitude-biased source estimates, it has difficulties in separating close sources, and it has a high computational complexity due to its implementation using second order cone programming. To overcome these problems, we propose to include an additional regularization term that imposes sparsity in the original source domain and to solve the resulting optimization problem using the alternating direction method of multipliers. Furthermore, we show that the algorithm yields more robust solutions by taking into account the temporal structure of the data. We also propose a new method to automatically threshold the estimated source distribution, which permits to delineate the active brain regions. The new algorithm, called Source Imaging based on Structured Sparsity (SISSY), is analyzed by means of realistic computer simulations and is validated on the clinical data of four patients.
Content may be subject to copyright.
UNCORRECTED PROOF
(9IFC#A5;9 LLL  LLLLLL
CBH9BHG@=GHG5J5=@56@95H-7=9B79=F97H
(9IFC#A5;9
>CIFB5@<CA9D5;9KKK9@G9J=9F7CA
-#--3 B 9U7=9BH 5B8 5IHCA5H=7 5@;CF=H<A :CF H<9 5B5@MG=G C: ! GCIF79G 65G98 CB
GHFI7HIF98 GD5FG=HM
" 97?9FZ5 & @69F5Z6Z Z7Z Z8Z Z * CACBZ9 $ (IB9GZ6Z Z7 , !F=6CBJ5@Z8 $ @9IF95IZ5 * !I=@@CH9@Z5 # '9F@9HZ6Z Z7
5%-+051+6369 # 9)5+- -::65$é=1/5é 9)5+-
6$# & #-55-:  9)5+-
7&51=-9:1;é,- #-55-:  %$ #-55-:  9)5+-
8-5;9- # #-55-:9-;)/5- ;3)5;18<- #-55-:  9)5+-
9!$)* #$ &# 9-56*3- )47<: !  $; )9;15 ,-9-: -,-?  9)5+-
,.#& #( )
-@>69,:
!
-D5FG=HM
''
LH9B898 GCIF79 @C75@=N5H=CB
-.,.
)J9F H<9 D5GH 897589G 5 AI@H=HI89 C: 8=::9F9BH 6F5=B GCIF79 =A5;=B; 5@;CF=H<AG <5J9 699B 89J9@CD98 HC =89BH=:M
H<9 B9IF5@ ;9B9F5HCFG IB89F@M=B; H<9 GIF:579 9@97HFC9B79D<5@C;F5D<M A95GIF9A9BHG 1<=@9 ACGH C: H<9G9 H97<
B=EI9G :C7IG CB 89H9FA=B=B; H<9 GCIF79 DCG=H=CBG CB@M 5 GA5@@ BIA69F C: F979BH@M 89J9@CD98 5@;CF=H<AG DFC
J=89G 5B =B8=75H=CB C: H<9 :7);1)3 -?;-5; C: H<9 8=GHF=6IH98 GCIF79G #B 5 F979BH 7CAD5F=GCB C: 6F5=B GCIF79 =A5;=B;
5DDFC57<9G H<9 0- 5@;CF=H<A <5G 699B G<CKB HC 69 CB9 C: H<9 ACGH DFCA=G=B; 5@;CF=H<AG 5ACB; H<9G9
A9H<C8G "CK9J9F H<=G H97<B=EI9 GI::9FG :FCA G9J9F5@ DFC6@9AG =H @958G HC 5AD@=HI896=5G98 GCIF79 9GH=A5H9G
=H <5G 8=:S7I@H=9G =B G9D5F5H=B; 7@CG9 GCIF79G 5B8 =H <5G 5 <=;< 7CADIH5H=CB5@ 7CAD@9L=HM 8I9 HC =HG =AD@9A9B
H5H=CB IG=B; G97CB8 CF89F 7CB9 DFC;F5AA=B; .C CJ9F7CA9 H<9G9 DFC6@9AG K9 DFCDCG9 HC =B7@I89 5B 588=H=CB5@
F9;I@5F=N5H=CB H9FA H<5H =ADCG9G GD5FG=HM =B H<9 CF=;=B5@ GCIF79 8CA5=B 5B8 HC GC@J9 H<9 F9GI@H=B; CDH=A=N5H=CB
DFC6@9A IG=B; H<9 5@H9FB5H=B; 8=F97H=CB A9H<C8 C: AI@H=D@=9FG IFH<9FACF9 K9 G<CK H<5H H<9 5@;CF=H<A M=9@8G
ACF9 FC6IGH GC@IH=CBG 6M H5?=B; =BHC 577CIBH H<9 H9ADCF5@ GHFI7HIF9 C: H<9 85H5 19 5@GC DFCDCG9 5 B9K A9H<C8
HC 5IHCA5H=75@@M H<F9G<C@8 H<9 9GH=A5H98 GCIF79 8=GHF=6IH=CB K<=7< D9FA=HG HC 89@=B95H9 H<9 57H=J9 6F5=B F9;=CBG
.<9 B9K 5@;CF=H<A 75@@98 -CIF79 #A5;=B; 65G98 CB -HFI7HIF98 -D5FG=HM -#--3 =G 5B5@MN98 6M A95BG C: F95@=GH=7
7CADIH9F G=AI@5H=CBG 5B8 =G J5@=85H98 CB H<9 7@=B=75@ 85H5 C: :CIF D5H=9BHG
1. Introduction
.<9 C6>97H=J9 C: 6F5=B GCIF79 =A5;=B; 7CBG=GHG =B F97CBGHFI7H=B; H<9
9@97HF=75@ 57H=J=HM 9J9FMK<9F9 =B H<9 6F5=B 65G98 CB GIF:579 @97HFC9B
79D<5@C;F5D<M ! F97CF8=B;G )J9F H<9 @5GH 897589G 5 @5F;9 BIA
69F C: 5@;CF=H<AG <5J9 699B 89J9@CD98 HC H<=G 9B8 G99 9; 5=@@9H 9H
5@  !F97< 9H 5@  1=D: 5B8 (5;5F5>5B  97?9F 9H 5@
 :CF F9J=9KG CB H<=G HCD=7 1<=@9 ACGH C: H<9G9 A9H<C8G G99A HC
69 56@9 HC 577IF5H9@M =89BH=:M H<9 GCIF79 DCG=H=CBG CB@M 5 GA5@@ BIA69F
C: 5@;CF=H<AG 5F9 5@GC GI=H56@9 :CF 89H9FA=B=B; H<9 GD5H=5@ 9LH9BH C: H<9
57H=J9 GCIF79 F9;=CBG "CK9J9F H<=G =G 5B =ADCFH5BH =GGI9 =B GCA9 5D
D@=75H=CBG GI7< 5G =B 9D=@9DGM CF 9L5AD@9 :CF GCA9 8FI;F9G=GH5BH D5
H=9BHG GI::9F=B; :FCA :C75@ 9D=@9DGM 5 GIF;=75@ =BH9FJ9BH=CB 75B 69 7CB
G=89F98 HC F9ACJ9 H<9 9D=@9DHC;9B=7 NCB9 K=H< H<9 C6>97H=J9 C: GHCDD=B;
H<9 C77IFF9B79 C: 9D=@9DH=7 G9=NIF9G #B H<9G9 75G9G H<9 DF97=G9 89@=B
95H=CB C: H<9 9D=@9DHC;9B=7 NCB9 7CBGH=HIH9G 5 7FI7=5@ GH9D C: H<9 DF9GIF
;=75@ 5B5@MG=G C: H<9 D5H=9BHG HC K<=7< 6F5=B GCIF79 @C75@=N5H=CB 75B 7CB
HF=6IH9 =HG G<5F9 9; 6M <9@D=B; HC ;I=89 =BHF57F5B=5@ ! F97CF8=B;G
BCH<9F 8=:S7I@HM =B 6F5=B GCIF79 =A5;=B; 5F=G9G =B H<9 7CBH9LH C: DFCD
5;5H=CB D<9BCA9B5 1<9B 9D=@9DH=7 57H=J=HM GDF958G :FCA CB9 6F5=B F9
;=CB HC 5BCH<9F H<=G @958G HC G9J9F5@ G=AI@H5B9CIG@M 57H=J9 GCIF79 F9
;=CBG K=H< <=;<@M 7CFF9@5H98 57H=J=H=9G #B H<=G G=HI5H=CB 5B 5@;CF=H<A
K<=7< 75B =89BH=:M H<9 DCG=H=CBG 5B8 GD5H=5@ 9LH9BHG C: AI@H=D@9 GCIF79
F9;=CBG =G 89G=F56@9
 $;);-6.;0-)9;
.<9 SFGH GCIF79 =A5;=B; 5@;CF=H<A HC H5?9 =BHC 577CIBH 89D9B89B
7=9G 69HK99B 58>579BH ;F=8 8=DC@9G K5G DFC656@M H<9 6> #-:63<;165
3-+;964)/5-;1+ %646/9)70@  #% A9H<C8 *5G7I5@'5FEI= 9H 5@
 &),. =ADCG9G GD5H=5@ GACCH<B9GG CB H<9 GCIF79 8=GHF=6IH=CB
K<=7< 75B 69 F9;5F898 5G H<9 SFGH GH9D HCK5F8G 5 H97<B=EI9 H<5H =G 56@9
HC @C75@=N9 GCIF79G C: GCA9 GD5H=5@ 9LH9BH IH CB H<9 CB9 <5B8 H<9
GACCH<B9GG 7CBGHF5=BH 5::97HG CB@M H<9 =AA98=5H9 B9=;<6CFG C: 5 ;F=8
CFF9GDCB89B79 HC &.-# 5ADIG 89 95I@=9I /B=J9FG=H9 89 ,9BB9G   J9BI9 8I !9B9F5@ &97@9F7 -   ,9BB9G 989L F5B79
4)13 ),,9-:: @5IF9BH5@69F5IB=JF9BB9G:F & @69F5
<HHD8L8C=CF;>B9IFC=A5;9
,979=J98 (CJ9A69F779DH98 '5M
J5=@56@9CB@=B9 LLL
 O*I6@=G<986M@G9J=9F&H8
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
8=DC@9 5B8 =G H<9F9:CF9 HCC @C75@ HC 69 9::97H=J9 :CF GCIF79G C: @5F;9F 9L
H9BH )B H<9 CH<9F <5B8 H<9 F9GI@H=B; ;F58I5@ 7<5B;9G C: 5AD@=HI89 CJ9F
GD579 5@GC A5?9 =H 8=:S7I@H HC 89@=B95H9 H<9 GCIF79 F9;=CBG 5B8 HC 8=GH=B
;I=G< 7@CG9 GCIF79G
#B CF89F HC @C75@=N9 9LH9B898 GCIF79G &=AD=H=  =BHFC8I798 H<9
+69;1+)3 7);+0 46,-3 7CBG=GH=B; C: 5 G9H C: DF989SB98 D5F5A9H9F=N98
GCIF79 F9;=CBG .<9G9 GC75@@98 D5H7<9G K9F9 H<9B 9AD@CM98 =B 5 695A
:CFA=B; 5DDFC57< HC =89BH=:M H<9 GCIF79 F9;=CBG K<=7< 69GH 89G7F=698
H<9 A95GIF9A9BHG .<9 =895 C: IG=B; 5 SL98 G9H C: GCIF79 F9;=CBG K5G
5@GC H5?9B ID =B H<9 89J9@CDA9BH C: G9J9F5@ CH<9F 9LH9B898 GCIF79 @C
75@=N5H=CB 5DDFC57<9G =B7@I8=B; H<9 E;0 69,-9 ?;-5,-, $6<9+- <3;1
73- $1/5)3 3)::1B+);165 E?$6&$ 5@;CF=H<A =FCH 9H 5@ 
H<5H 9LD@C=HG H<9 EH< CF89F GH5H=GH=7G C: H<9 ! F97CF8=B;G K=H< 5B
CDH=A=N5H=CB GHF5H9;M 65G98 CB 5 1:2 3/691;04  5@GC IG98 :CF
H9BGCF65G98 GCIF79 @C75@=N5H=CB 97?9F 9H 5@ 7 .<9G9 A9H<C8G
57<=9J9 5 ;CC8 D9F:CFA5B79 :CF H<9 @C75@=N5H=CB C: 5 G=B;@9 9LH9B898
GCIF79 CF =B H<9 75G9 C: H9BGCF65G98 GCIF79 @C75@=N5H=CB 5@GC C: 5
GA5@@ BIA69F C: GCIF79G DFCJ=898 H<5H H<9M 5F9 577IF5H9@M G9D5F5H98 6M
H<9 H9BGCF 897CADCG=H=CB GH9D "CK9J9F @C75@=N=B; G9J9F5@ <=;<@M 7CFF9
@5H98 GCIF79 F9;=CBG F9A5=BG DFC6@9A5H=7 K=H< H<9G9 H97<B=EI9G
 8=::9F9BH 5DDFC57< :CF H<9 @C75@=N5H=CB C: 9LH9B898 GCIF79G <5G
699B DIFGI98 6M =B;  K<C DFCDCG98 H<9 ')91);165):-, $7)9:-
69;1+)3 <99-5; 1:;91*<;165 '$ 5@;CF=H<A .<=G GCIF79 =A5;=B;
A9H<C8 =89BH=S9G D=979K=G9 7CBGH5BH GCIF79 8=GHF=6IH=CBG 6M =ADCG=B;
GD5FG=HM CB H<9 J5F=5H=CB5@ A5D K<=7< 7<5F57H9F=N9G H<9 J5F=5H=CBG =B
5AD@=HI89 C: 58>579BH ;F=8 8=DC@9G #B 5 F979BH 7CAD5F=GCB C: 8=::9F9BH
GCIF79 =A5;=B; 5@;CF=H<AG 97?9F 9H 5@ 6  H<9 0-
5@;CF=H<A <5G 699B G<CKB HC M=9@8 5 ;CC8 D9F:CFA5B79 :CF H<9 @C75@
=N5H=CB C: 9LH9B898 GCIF79G #B D5FH=7I@5F =H D9FA=HG HC G=AI@H5B9CIG@M
@C75@=N9 G9J9F5@ <=;<@M 7CFF9@5H98 57H=J9 GCIF79 F9;=CBG K<=7< A5?9G =H
CB9 C: H<9 ACGH DFCA=G=B; 5DDFC57<9G :CF H<9 =89BH=S75H=CB C: AI@H=D@9
6F5=B F9;=CBG =B H<9 7CBH9LH C: DFCD5;5H=CB D<9BCA9B5 (9J9FH<9@9GG
H<9 5@;CF=H<A <5G GCA9 8F5K657?G
=H G<CKG 8=:S7I@H=9G =B G9D5F5H=B; 7@CG9 GCIF79G H9B8=B; HC 7CA6=B9
H<9A =BHC CB9 @5F;9 GCIF79
H<9 9GH=A5H98 GCIF79 8=GHF=6IH=CB A5M 69 5AD@=HI896=5G98 K<=7<
A95BG H<5H H<9F9 =G 5 GMGH9A5H=7 9FFCF CB H<9 9GH=A5H98 5AD@=HI89G
5B8
H<9 =AD@9A9BH5H=CB C: 0- IG=B; -97CB8 )F89F CB9 *FC;F5A
A=B; -)* @=N589< 5B8 !C@8:5F6  5G DFCDCG98 =B =B;
 @958G HC 5 <=;< 7CADIH5H=CB5@ 7CAD@9L=HM K<=7< DF57H=75@@M
:CF6=8G H<9 5DD@=75H=CB C: H<9 A9H<C8 :CF @5F;9 BIA69FG C: H=A9 G5A
D@9G
 65;91*<;165:
.C CJ9F7CA9 H<9 DFC6@9AG C: 0- K9 DFCDCG9 5 B9K A9H<C8
75@@98 $6<9+- 4)/15/ *):-, 65 $;9<+;<9-, $7)9:1;@ $$$( .<=G 5@;CF=H<A
=B7@I89G 5B 588=H=CB5@ ZBCFA F9;I@5F=N5H=CB H9FA K<=7< =ADCG9G GD5F
G=HM CB H<9 9GH=A5H98 GCIF79 8=GHF=6IH=CB -I7< 5B 5DDFC57< 5@GC ?BCKB
5G GD5FG9 .CH5@ 05F=5H=CB GD5FG9 .0 F9;I@5F=N5H=CB 5@85GG5FF9 9H 5@
 .0Z F9;I@5F=N5H=CB !F5A:CFH 9H 5@  CF :IG98 &--)
.=6G<=F5B= 5B8 -5IB89FG  <5G DF9J=CIG@M 699B IG98 =B =A5;9 DFC
79GG=B; '5 9H 5@  5B8 :',# DF98=7H=CB 5@85GG5FF9 9H 5@ 
!F5A:CFH 9H 5@  K<9F9 =H <5G 699B G<CKB HC @958 HC FC6IGH GC
@IH=CBG 6IH =G B9K =B H<9 S9@8 C: 6F5=B GCIF79 =A5;=B; (CH9 H<CI;<
H<5H H<9 7CA6=B5H=CB C: GD5FG=HM =B H<9 CF=;=B5@ GCIF79 8CA5=B 5B8 =B 5
HF5BG:CFA98 8CA5=B H<5H =G 8=::9F9BH :FCA H<9 HCH5@ J5F=5H=CB <5G 699B
9LD@CF98 =B <5B; 9H 5@  :CF '! GCIF79 =A5;=B; .<5B?G HC
H<=G F9;I@5F=N5H=CB GHF5H9;M H<9 -#--3 5@;CF=H<A =G 56@9 HC G9D5F5H9 9J9B
7@CG9 GCIF79G 5B8 5JC=8G 5AD@=HI896=5G98 GCIF79 9GH=A5H9G #B 588=H=CB
K9 A5?9 H<9 :C@@CK=B; 7CBHF=6IH=CBG
19 DFCDCG9 HC H5?9 =BHC 577CIBH H<9 H9ADCF5@ GHFI7HIF9 C: H<9 GCIF79
8=GHF=6IH=CB 6M 58CDH=B; 5B ZBCFA F9;I@5F=N5H=CB GHF5H9;M 5G SFGH
GI;;9GH98 =B )I 9H 5@  @958=B; HC ACF9 FC6IGH GCIF79 9GH=A5
H=CB
19 GC@J9 H<9 F9GI@H=B; CDH=A=N5H=CB DFC6@9A IG=B; H<9 @H9FB5H=B; =
F97H=CB '9H<C8 C: 'I@H=D@=9FG '' !565M 5B8 '9F7=9F 
!@CK=BG?= 5B8 '5FFC77C  CM8 9H 5@  K<=7< 7CBG=89F
56@M F98I79G H<9 7CADIH5H=CB5@ 7CAD@9L=HM 7CAD5F98 HC H<9 -)* 5@
;CF=H<A 9AD@CM98 6M 0-
19 DFCDCG9 5 B9K A9H<C8 :CF G9@97H=B; H<9 F9;I@5F=N5H=CB D5F5A9H9F
K<=7< 8C9G BCH F9EI=F9 H<9 9GH=A5H=CB C: H<9 BC=G9 @9J9@
19 89J9@CD 5 H97<B=EI9 HC 5IHCA5H=75@@M H<F9G<C@8 H<9 9GH=A5H98
GCIF79 8=GHF=6IH=CB 65G98 CB H<9 K5H9FG<98 HF5BG:CFA 0=B79BH 5B8
-C=@@9  K<=7< =G 5 G9;A9BH5H=CB A9H<C8 7CAACB@M IG98 =B =A
5;9 DFC79GG=B;
.C;9H<9F K=H< H<9 DFCDCG98 F9;I@5F=N5H=CB GHF5H9;M H<9 5IHCA5H=7
H<F9G<C@8=B; H97<B=EI9 A5?9G H<9 -#--3 5@;CF=H<A 95GM HC IG9 =B 7@=B=
75@ DF57H=79 G=B79 =H 8C9G BCH F9EI=F9 H<9 H98=CIG HIB=B; C: D5F5A9H9FG 
7CBHF5FM HC ACGH CH<9F 7IFF9BH@M 5J5=@56@9 H97<B=EI9G
.C 5B5@MN9 H<9 D9F:CFA5B79 C: H<9 -#--3 5@;CF=H<A =B 7CAD5F=GCB HC
GH5H9C:H<95FH 9LH9B898 GCIF79 @C75@=N5H=CB A9H<C8G K9 7CB8I7H 5B 9L
H9BG=J9 G=AI@5H=CB GHI8M K=H< <=;<@M F95@=GH=7 ! 85H5 IFH<9FACF9 =B
CF89F HC J5@=85H9 H<9 DFCDCG98 5DDFC57< CB 7@=B=75@ ! 85H5 K9 5DD@M
H<9 -#--3 5@;CF=H<A HC H<9 ! F97CF8=B;G C: :CIF 9D=@9DH=7 D5H=9BHG :CF
K<=7< 5 GHFCB; <MDCH<9G=G CB H<9 9D=@9DHC;9B=7 NCB9 =G 5J5=@56@9
 9/)51A);165 6. ;0- 7)7-9
.<=G D5D9F =G CF;5B=N98 5G :C@@CKG =B -97H=CB  K9 =BHFC8I79 H<9
IB89F@M=B; 85H5 AC89@ 5B8 6F=9TM F9J=9K H<9 0- 5@;CF=H<A 69
:CF9 DF9G9BH=B; H<9 DFCDCG98 -#--3 A9H<C8 IFH<9FACF9 K9 89G7F=69
H<9 G=AI@5H=CB G9HID 5B8 H<9 7@=B=75@ 85H5 H<5H 5F9 IG98 HC 9J5@I5H9 H<9
-#--3 5@;CF=H<A -97H=CB  H<9B DF9G9BHG H<9 F9GI@HG C6H5=B98 CB G=A
I@5H98 5B8 F95@ 85H5 =B5@@M CIF SB8=B;G 5F9 8=G7IGG98 =B -97H=CB 
-97H=CB  7CB7@I89G H<9 D5D9F
*@95G9 BCH9 H<5H D5FHG C: H<=G KCF? <5J9 DF9J=CIG@M 699B DF9G9BH98 =B
97?9F 9H 5@ 5
2. Methods
 );) 46,-3
'5H<9A5H=75@@M H<9 6F5=B 9@97HF=75@ 7IFF9BHG F9GI@H=B; :FCA H<9 9@97
HFC7<9A=75@ DFC79GG C: =B:CFA5H=CB HF5BGA=GG=CB 69HK99B B9IFCBG 75B
69 AC89@98 IG=B; 5 ;F=8 C: 7IFF9BH 8=DC@9G K<9F9 957< 8=DC@9 F9DF9G9BHG
5 B9IFCB5@ DCDI@5H=CB K=H< GMB7<FCB=N98 57H=J=HM .<9G9 8=DC@9G :CFA
H<9 GCIF79 GD579 G H<9 G=;B5@G H<5H 5F9 F97CF898 6M H<9 G75@D 9@97HFC89G
5F9 ?BCKB HC CF=;=B5H9 DF=A5F=@M :FCA H<9 DMF5A=85@ B9IFCBG =B H<9
;F5M A5HH9F K<=7< 5F9 5FF5B;98 =B D5F5@@9@ K=H< 5B CF=9BH5H=CB D9FD9B
8=7I@5F HC H<9 GIF:579 =H =G D<MG=C@C;=75@@M D@5IG=6@9 HC 9AD@CM 5 GCIF79
GD579 H<5H =G 7CADCG98 C: 8=DC@9G @C75H98 CB H<9 7CFH=75@ GIF:579 K=H< 5B
CF=9BH5H=CB D9FD9B8=7I@5F HC H<=G GIF:579 5@9 5B8 -9F9BC  G
GIA=B; H<5H H<9 8MB5A=7G C: 5@@ GCIF79 8=DC@9G 5F9 7<5F57H9F=N98 6M H<9
G=;B5@ A5HF=L -,Y. K<9F9 %89BCH9G H<9 BIA69F C: H=A9 G5AD@9G 5B8
=G H<9 BIA69F C: GCIF79 8=DC@9G H<9 ! 85H5 2,(Y. F97CF898 6M
G9BGCFG 7CFF9GDCB8 HC 5 @=B95F A=LHIF9 C: H<9 GCIF79 G=;B5@G

.<9 A=LHIF9 =G 7<5F57H9F=N98 6M H<9 @958 S9@8 A5HF=L !,(Y K<=7<
89G7F=69G H<9 5HH9BI5H=CB =BT=7H98 CB H<9 8=DC@9 G=;B5@G 8IF=B; H<9
8=::IG=CB =B H<9 <958 JC@IA9 7CB8I7HCF !=J9B 5 <958 AC89@ 5B8 5
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
GCIF79 GD579 H<9 @958 S9@8 A5HF=L 75B 69 7CADIH98 BIA9F=75@@M IG=B; 5
CIB85FM @9A9BH '9H<C8 ' !F5A:CFH 
B 9LH9B898 GCIF79 5@GC F9:9FF98 HC 5G 5 D5H7< 7CFF9GDCB8G HC 5
7CBH=;ICIG 5F95 C: 7CFH9L K=H< <=;<@M 7CFF9@5H98 57H=J=H=9G 5B8 75B 69
AC89@98 6M 5 BIA69F C: 58>579BH ;F=8 8=DC@9G K=H< GMB7<FCB=N98 G=;
B5@G .<9 =B8=79G C: 5@@ ;F=8 8=DC@9G :CFA=B; H<9 7H< 9LH9B898 GCIF79
7! 5F9 GHCF98 =B H<9 G9H ΩZ7 .<9 GCIF79 GD579 75B H<9B 69 8=J=898
=BHC HKC G9HG 5B8 ΩZ* K<=7< 7CBH5=B F9GD97H=J9@M H<9 =B
8=79G C: H<9 ;F=8 8=DC@9G 69@CB;=B; HC H<9 !9LH9B898 GCIF79G 5B8 H<9
=B8=79G C: H<9 F9A5=B=B; 8=DC@9G C: H<9 GCIF79 GD579 K<=7< 5F9 5GGIA98
HC 9A=H BCFA5@ 657?;FCIB8 57H=J=HM C: H<9 6F5=B .<9 85H5 AC89@ 75B
H<9B 69 F9KF=HH9B 5G

K<9F9 gZ? 5B8 7CFF9GDCB8 HC H<9 2H< 7C@IAB C: G5B8 H<9 2H< FCK C:
S F9GD97H=J9@M .<9 A5HF=L XZ9 7<5F57H9F=N9G H<9 ! 85H5 C: H<9 9D=@9D
H=7 GCIF79G 5B8 XZ6 7CFF9GDCB8G HC H<9 657?;FCIB8 57H=J=HM
 $6<9+- 36+)31A);165 )5, -?;9)+;165
.<9 C6>97H=J9 C: 6F5=B GCIF79 =A5;=B; 7CBG=GHG =B 9GH=A5H=B; H<9 G=;
B5@ A5HF=L S:FCA H<9 85H5 X:CF 5 ?BCKB @958 S9@8 A5HF=L G G H<9 657?
;FCIB8 57H=J=HM C: H<9 6F5=B 75B 69 5GGIA98 HC 69 C: GA5@@ 5AD@=HI89
7CAD5F98 HC H<9 GCIF79 57H=J=HM =H =G H<9B DCGG=6@9 HC =89BH=:M H<9 8=DC@9G
69@CB;=B; HC H<9 G9H ΩZ-5B8 H<9F96M H<9 9LH9B898 GCIF79G 6M H<F9G<C@8
=B; H<9 5AD@=HI89G C: H<9 9GH=A5H98 G=;B5@ A5HF=L -I6G9EI9BH@M K9 DFC
J=89 5 G<CFH F9J=9K C: H<9 7@5GG=75@ 0- GCIF79 =A5;=B; 5@;CF=H<A
69:CF9 DFC7998=B; HC 89G7F=69 H<9 DFCDCG98 -#--3 5DDFC57<
 '$
.<9 0- 5@;CF=H<A =B;  5GGIA9G 5 D=979K=G9 7CBGH5BH
GD5H=5@ GCIF79 8=GHF=6IH=CB K<=7< =G 57<=9J98 6M =ADCG=B; GD5FG=HM CB
H<9 J5F=5H=CB5@ A5D C: H<9 GCIF79G .<9 J5F=5H=CB5@ A5D 89G7F=69G H<9
8=::9F9B79G =B 5AD@=HI89 69HK99B 58>579BH 8=DC@9G #H 75B 69 7CADIH98
6M 5DD@M=B; 5 @=B95F HF5BG:CFA 7<5F57H9F=N98 6M H<9 A5HF=L V HC H<9
GCIF79 8=GHF=6IH=CB K<=7< =G 9EI=J5@9BH HC 7CADIH=B; H<9 HCH5@ J5F=5H=CB
CB H<9 8=G7F9H=N98 7CFH=75@ GIF:579 .<9 9@9A9BHG 098 C: V-
, K<9F9 =G H<9 BIA69F C: 98;9G C: H<9 HF=5B;I@5F ;F=8 5F9
;=J9B 6M

K<9F9 89 5B8 89 5F9 H<9 =B8=79G C: H<9 8=DC@9G G<5F=B; H<9 -H< 98;9
.<=G 89:=B=H=CB 75B 5@GC 69 9LH9B898 HC AC89@G K<9F9 H<9 GCIF79 8=DC@9G
5F9 D@5798 5H H<9 J9FH=79G C: H<9 ;F=8 .<9 C6>97H=J9 C: 0- H<9B
7CBG=GHG =B GC@J=B; H<9 :C@@CK=B; CDH=A=N5H=CB DFC6@9A

K<9F9 5B8 7CFF9GDCB8 HC H<9 ;H< 7C@IABG ;% C: H<9 85H5
5B8 G=;B5@ A5HF=79G F9GD97H=J9@M 5B8 δ=G 5 F9;I@5F=N5H=CB D5F5A9H9F
.<=G D5F5A9H9F A5M 69 58>IGH98 577CF8=B; HC H<9 5779DH56@9 IDD9F @=A=H
:CF H<9 F97CBGHFI7H=CB 9FFCF  K<=7< 89D9B8G CB H<9 BC=G9
@9J9@ #B =B;  H<9 CDH=A=N5H=CB C:  =G D9F:CFA98 IG=B; -97CB8
)F89F CB9 *FC;F5AA=B; -)* @=N589< 5B8 !C@8:5F6  CM8
5B8 05B89B69F;<9 
 $$$(
#B DF57H=79 =H =G F95GCB56@9 HC 5GGIA9 H<5H CB@M 5 GA5@@ BIA69F C:
H<9 GCIF79 8=DC@9G 7CBHF=6IH9 HC H<9 G=;B5@G C: =BH9F9GH "9B79 K9 =BHFC
8I79 5B 588=H=CB5@ F9;I@5F=N5H=CB H9FA H<5H =ADCG9G GD5FG=HM =B H<9 CF=;
=B5@ GCIF79 8CA5=B 'CF9CJ9F K9 :CFAI@5H9 H<9 CDH=A=N5H=CB DFC6@9A
=B 5 G@=;<H@M 8=::9F9BH K5M K<=7< 9B56@9G IG HC IG9 5 ACF9 9:S7=9BH CD
H=A=N5H=CB 5@;CF=H<A .<9 -#--3 GCIF79 9GH=A5H9 =G H<IG C6H5=B98 5G H<9
GC@IH=CB HC H<9 :C@@CK=B; CDH=A=N5H=CB DFC6@9A K<=7< =G 9EI=J5@9BH HC
H<9 GD5FG9 .0 5@85GG5FF9 9H 5@  CF :IG98 &--) .=6G<=F5B= 5B8
-5IB89FG  5DDFC57<

.<9 F9;I@5F=N5H=CB D5F5A9H9F λ65@5B79G 69HK99B H<9 F97CBGHFI7H=CB 9F
FCF 5B8 H<9 7CBGHF5=BH 7CFF9GDCB8=B; HC H<9 SFGH 5B8 G97CB8 H9FA =B 
F9GD97H=J9@M 5B8 75B 69 G99B 5G 5B 9EI=J5@9BH C: H<9 F9;I@5F=N5H=CB D5
F5A9H9F δ9AD@CM98 6M 0- .<9 -#--3 GC@IH=CB 5@GC 89D9B8G CB
H<9 588=H=CB5@ F9;I@5F=N5H=CB D5F5A9H9F α 05FM=B; H<=G D5F5A9H9F D9F
A=HG IG HC 58>IGH H<9 G=N9 C: H<9 F97CBGHFI7H98 GCIF79 F9;=CB H<9 @5F;9F
α H<9 GA5@@9F H<9 9GH=A5H98 GCIF79 5B8 DF9J9BHG H<9 9GH=A5H98 G=;B5@
J97HCF :FCA :95HIF=B; 5 @5F;9 5AD@=HI89 6=5G K<=7< =G 5 DFC6@9A H<5H
:F9EI9BH@M 5F=G9G IG=B; H<9 0- 5@;CF=H<A CF R  H<9 -#--3
5@;CF=H<A =G H97<B=75@@M 9EI=J5@9BH HC 0- K<9F95G G9HH=B; R  
@958G HC J9FM :C75@ GCIF79 9GH=A5H9G K=H<CIH 5AD@=HI89 6=5G 1<=@9 H<=G
D5F5A9H9F 7CI@8 5@GC 69 7<CG9B ;F95H9F H<5B  F95GCB56@9 F9GI@HG 5F9
C6H5=B98 K<9B α@=9G K=H<=B H<9 =BH9FJ5@  .<9 F9;I@5F=N5H=CB D5F5
A9H9F λ=G ;9B9F5@@M 58>IGH98 65G98 CB 5B 9GH=A5H9 C: H<9 BC=G9 @9J9@
"CK9J9F G=B79 H<9F9 =G BC 8=F97H F9@5H=CB 69HK99B λ5B8 H<9 BC=G9 @9J9@
 7CBHF5FM HC H<9 F9;I@5F=N5H=CB D5F5A9H9F δ=B  K<=7< 8=F97H@M 7CF
F9GDCB8G HC H<9 IDD9F @=A=H C: H<9 F97CBGHFI7H=CB 9FFCF  8=::9F9BH J5@I9G
C: λB998 HC 69 H9GH98 =B CF89F HC C6H5=B 5 F97CBGHFI7H=CB 9FFCF H<5H @=9G
K=H<=B 5 ;=J9B =BH9FJ5@ "9F9 K9 5@GC DFCDCG9 5B 5@H9FB5H=J9 5DDFC57<
:CF 7<CCG=B; H<9 F9;I@5F=N5H=CB D5F5A9H9F λ K<=7< =G 65G98 CB H<9 :C@
@CK=B; C6G9FJ5H=CBG =B CF89F HC =ADCG9 GD5FG=HM CB H<9 GCIF79G 5B8 H<9
J5F=5H=CB5@ A5D K9 KCI@8 =895@@M 9AD@CM 5B ZBCFA F9;I@5F=N5H=CB
"CK9J9F 5G =H =G A5H<9A5H=75@@M BCH DCGG=6@9 HC GC@J9 H<9 ZBCFA CD
H=A=N5H=CB DFC6@9A =B 5 F95GCB56@9 5ACIBH C: H=A9 (*<5F8 DFC6@9A
K9 F9GCFH HC ZBCFA F9;I@5F=N5H=CB =BGH958 :CF K<=7< 9:S7=9BH GC@J9FG
9L=GH (CK 7CAD5F=B; H<9 ZBCFA 5B8 ZBCFA F9;I@5F=N5H=CB H9FAG C:
H<9 GC@IH=CBG C6H5=B98 :CF G9J9F5@ 8=::9F9BH J5@I9G C: λ K9 BCH9 H<5H ID
HC 5 79FH5=B J5@I9 =B7F95G=B; λ =9 =B7F95G=B; H<9 =AD57H C: H<9 F9;I
@5F=N5H=CB H9FA 9::97H=J9@M @958G HC 5 897F95G9 C: 6CH< H<9 ZBCFA 5B8
H<9 ZBCFA C: H<9 F9;I@5F=N5H=CB H9FAG 39H 56CJ9 H<=G H<F9G<C@8 J5@I9
CB@M H<9 ZBCFA ?99DG 897F95G=B; K<9F95G H<9 ZBCFA =B7F95G9G 5;5=B
)IF =895 =G HC G9@97H 5ACB; H<9 H9GH98 J5@I9G H<9 F9;I@5F=N5H=CB D5F5
A9H9F H<5H 7CFF9GDCB8G HC H<=G H<F9G<C@8 H<IG <9IF=GH=75@@M A=B=A=N=B;
H<9 ZBCFA F9;I@5F=N5H=CB H9FA X0-X RX-X
?7361;);165 6. ;-4769)3 :;9<+;<9- .<9 -#--3 5@;CF=H<A 5G 89G7F=698 =B
H<9 DF9J=CIG G97H=CB 7CBG=89FG 957< H=A9 G5AD@9 =B89D9B89BH@M 5B8 H<IG
8C9G BCH H5?9 =BHC 577CIBH H<9 H9ADCF5@ GHFI7HIF9 C: H<9 85H5 "CK9J9F
=H 75B 69 9LD97H98 H<5H =: CB@M 5 G<CFH H=A9 =BH9FJ5@ =G 7CBG=89F98 7CFF9
GDCB8=B; 9; HC H<9 8IF5H=CB C: 5B =BH9F=7H5@ 9D=@9DH=7 GD=?9 H<9 57H=J9
GCIF79 F9;=CBG GH5M H<9 G5A9 .<=G <MDCH<9G=G 75B 69 9B:CF798 6M F9D@57
=B; H<9 ZBCFA =B  6M H<9 &BCFA K<=7< =G 89SB98 5G :C@@CKG
 .<9 &BCFA DFCACH9G 5 FCKGD5FG9 GHFI7HIF9
K=H< 5 GA5@@ BIA69F C: BCBN9FC FCKG 7CFF9GDCB8=B; HC 57H=J9 8=DC@9G
5B8 A5BM N9FC FCKG :CF =B57H=J9 8=DC@9G .<=G D9FA=HG HC C6H5=B ACF9 FC
6IGH GCIF79 9GH=A5H9G .<9 F9GI@H=B; GCIF79 @C75@=N5H=CB 5DDFC57< =G GI6
G9EI9BH@M 75@@98 &-#--3
7;141A);165 <:15/  .<9 CDH=A=N5H=CB DFC6@9AG C: 6CH< 5@;C
F=H<AG -#--3 5B8 &-#--3 75B 69 F9KF=HH9B =B 5 ;9B9F5@=N98 7CB
GHF5=B98 CDH=A=N5H=CB :F5A9KCF? K=H< @5H9BH J5F=56@9G Y5B8 Z

"9F9 .F9DF9G9BHG H<9 F9;I@5F=N5H=CB :IB7H=CB H<5H =G 9=H<9F H<9 Z
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
BCFA :CF -#--3 CF H<9 &BCFA :CF &-#--3 *FC6@9A  75B
69 GC@J98 IG=B; '' !565M 5B8 '9F7=9F  !@CK=BG?= 5B8
'5FFC77C  CM8 9H 5@  K<=7< =G 5 G=AD@9 5B8 9:S7=9BH 5@;C
F=H<A :CF 7CBGHF5=B98 7CBJ9L CDH=A=N5H=CB #H =G 65G98 CB H<9 =895 C: 5@
H9FB5H=B;@M ID85H=B; H<9 J5F=56@9G -,Y. 3,*Y. 5B8 4,Y. =B H<9
5I;A9BH98 &5;F5B;=5B C:  5G K9@@ 5G 7CADIH=B; 5@H9FB5H=B; ID85H9G
C: H<9 G75@98 &5;F5B;=5B AI@H=D@=9FG /,*Y. 5B8 1,Y. :H9F =B=H=5@
=N5H=CB :CF 9L5AD@9 6M G9HH=B; 5@@ J5F=56@9G HC N9FC 5H H<9 2H< =H9F5
H=CB H<9 :C@@CK=B; ID85H9 FI@9G 75B 69 89F=J98
K<9F9 89BCH9G H<9 D9B5@HM D5F5A9H9F =BHFC8I798 =B H<9 5I;A9BH98
&5;F5B;=5B G99 CM8 9H 5@  <9F9 K9 G9H W   *@95G9 BCH9 H<5H
=B DF57H=79 H<9 7CADIH5H=CB C: H<9 =BJ9FG9 C: H<9 @5F;9 A5HF=L *,Y
G<CI@8 69 5JC=898 :CF 9L5AD@9 6M F9GCFH=B; HC 5B =BJ9FG=CB @9AA5 5B8
A5HF=L 897CADCG=H=CBG GI7< 5G H<9 +,897CADCG=H=CB K<=7< 75B 69
7CADIH98 9:S7=9BH@M .<9 ID85H9G C: Y5B8 Z5F9 :CFAI@5H98 IG=B; H<9
DFCL=A=HM CD9F5HCF CF=;=B5@@M =BHFC8I798 =B 'CF95I  K<=7< =G
;=J9B 6M

-C@IH=CBG HC  :CF .7CFF9GDCB8=B; HC H<9 ZBCFA ?BCKB 5G
GC:HH<F9G<C@8=B; CF H<9 &BCFA C: X75B 69 :CIB8 =B CA69HH9G 5B8
*9GEI9H  !F5A:CFH 9H 5@  .<9 5@;CF=H<A =G GHCDD98 5:H9F
7CBJ9F;9B79 CF 5 A5L=A5@ BIA69F C: =H9F5H=CBG =G F957<98
 <;64);1+ ;09-:063,15/
.C 89@=B95H9 H<9 GCIF79 F9;=CBG :FCA H<9 9GH=A5H98 GCIF79 8=GHF=6I
H=CBG H<9 8=DC@9 5AD@=HI89G B998 HC 69 H<F9G<C@898 9D9B8=B; CB H<9
G9@97H98 H<F9G<C@8 H<9 GCIF79 9GH=A5H9G 75B H<IG J5FM 7CBG=89F56@M =B
G=N9 5B8 :CFA .C CJ9F7CA9 H<=G DFC6@9A K9 DFCDCG9 5B IHCA5H=7
.<F9G<C@8=B; . A9H<C8 5DD@=98 =B 5 G97CB8 GH9D 5:H9F H<9 9GH=A5H=CB
C: H<9 G=;B5@ A5HF=L H<5H @958G HC 5B C6>97H=J9 89@=B95H=CB C: H<9 GCIF79
F9;=CBG 65G98 CB H<9 ;F58=9BH C: H<9 9GH=A5H98 GCIF79 8=GHF=6IH=CB .<9
DFCDCG98 A9H<C8 =G 65G98 CB H<9 K5H9FG<98 HF5BG:CFA 0=B79BH 5B8
-C=@@9  K<=7< =G 7CAACB@M IG98 :CF =A5;9 G9;A9BH5H=CB 5B8
7CBG=GHG C: H<F99 GH9DG
$;-7  .<9 HF=5B;I@5F 7CFH=75@ GIF:579 75B 69 J=9K98 5G 5 ;F5D<
K<9F9 H<9 HF=5B;@9G ;F=8 8=DC@9G 7CFF9GDCB8 HC H<9 BC89G 5B8 H<9 98;9G
69HK99B HF=5B;@9G 7CFF9GDCB8 HC H<9 98;9G C: H<9 ;F5D< 57< 98;9 =G
5GG=;B98 5B 5AD@=HI89 H<5H =G 9EI5@ HC H<9 56GC@IH9 J5@I9 C: H<9 7CF
F9GDCB8=B; 9@9A9BH C: H<9 J5F=5H=CB5@ A5D .<9 SFGH GH9D C: H<9 .
A9H<C8 H<9B 7CBG=GHG =B 5DD@M=B; H<9 K5H9FG<98 HF5BG:CFA CB H<9 98;9G
C: H<9 ;F5D< .<9 K5H9FG<98 HF5BG:CFA H<IG D9FA=HG HC G9;A9BH H<9
GCIF79 GD579 =BHC ;FCIDG C: 58>579BH 8=DC@9G K=H< G=A=@5F 5AD@=HI89G
.<9 6CF89F 69HK99B 58>579BH ;FCIDG =G 7<5F57H9F=N98 6M 5B =B7F95G98
;F58=9BH 69HK99B 58>579BH 8=DC@9G .<=G @958G HC 5 SFGH D5F79@@=N5H=CB C:
H<9 GCIF79 GD579
$;-7  G H<9 BIA69F C: GCIF79 F9;=CBG =B H<=G SFGH D5F79@@=N5H=CB
=G GH=@@ F9@5H=J9@M <=;< G9J9F5@ 8CN9BG H<9 =89BH=S98 GCIF79 F9;=CBG 5F9
GI6G9EI9BH@M A9F;98 IBH=@ CB@M GCIF79 F9;=CBG H<5H 7CFF9GDCB8 HC 5 @C
75@ 5AD@=HI89 A5L=AIA CF A=B=AIA F9A5=B .C H<=G 9B8 H<9 :C@@CK=B;
DFC798IF9 =G 9AD@CM98
 #89BH=:M H<9 HKC 58>579BH GCIF79 F9;=CBG K=H< H<9 GA5@@9GH 8=::9F9B79
=B 5J9F5;9 5AD@=HI89
 '9F;9 H<9 F9;=CBG IB@9GG H<=G KCI@8 F98I79 H<9 BIA69F C: @C75@ 5A
D@=HI89 A5L=A5A=B=A5 9; HKC F9;=CBG 5F9 BCH 5@@CK98 HC A9F;9
=: H<=G KCI@8 @958 HC HKC 8=GH=B7H @C75@ A5L=A5 HC 697CA9 58>579BH CF
=: CB9 F9;=CB =G 5 @C75@ A5L=AIA 5B8 H<9 CH<9F F9;=CB 7CFF9GDCB8G HC
5 @C75@ A=B=AIA
 ,9D95H  5B8  IBH=@ H<9F9 F9A5=BG BC D5=F C: 58>579BH F9;=CBG H<5H
5F9 5@@CK98 HC 69 A9F;98
$;-7  :H9F =89BH=:M=B; 5@@ F9;=CBG 7CFF9GDCB8=B; HC @C75@ 5AD@=
HI89 9LHF9A5 K9 SB5@@M =89BH=:M H<9 F9;=CBG H<5H 7CBHF=6IH9 HC H<9 !
F97CF8=B;G =B 5 G=;B=:=75BH K5M 6M H<F9G<C@8=B; H<9 5J9F5;9 5AD@=HI89G
C: 5@@ F9;=CBG 6M 5 GI=H56@9 J5@I9 9;  C: H<9 A5L=AIA 5AD@=HI89
 $14<3);165:
.C 7CAD5F9 H<9 D9F:CFA5B79 C: -#--3 HC GH5H9C:H<95FH A9H<C8G
GI7< 5G -.10 L-C'/-# 5B8 7CFH=75@ &),. 7&),.
15;B9F 9H 5@  K9 7CB8I7H 5B 9LH9BG=J9 G=AI@5H=CB GHI8M K=H<
F95@=GH=7 ! 85H5 =B H<9 7CBH9LH C: =BH9F=7H5@ 9D=@9DH=7 9LH9B898 GCIF79
@C75@=N5H=CB
 );) /-5-9);165
19 ;9B9F5H9 D<MG=C@C;=75@@M D@5IG=6@9 ! 85H5 577CF8=B; HC H<9 :CF
K5F8 AC89@ 89G7F=698 =B -97H=CB  :CF  9@97HFC89G IG=B; 5 F95@=G
H=7 <958 AC89@ K=H< H<F99 7CAD5FHA9BHG H<5H F9DF9G9BH H<9 6F5=B H<9
G?I@@ 5B8 H<9 G75@D .<9 GCIF79 GD579 7CBG=GHG C:  8=DC@9G 7CF
F9GDCB8=B; HC H<9 HF=5B;@9G C: H<9 7CFH=75@ GIF:579 A9G< K=H< CF=9BH5
H=CBG D9FD9B8=7I@5F HC H<9 7CFH=75@ GIF:579  ' A9H<C8 - (.
BG7<989 (9H<9F@5B8G =G IG98 HC 7CADIH9 H<9 @958 S9@8 A5HF=L CF
G=AD@=7=HM K9 IG9 H<9 G5A9 JC@IA9 7CB8I7HCF 5B8 GCIF79 GD579 :CF H<9
:CFK5F8 5B8 H<9 =BJ9FG9 DFC6@9A *@95G9 BCH9 H<5H =B DF57H=79 AC89@=B;
9FFCFG 588=H=CB5@@M =AD57H H<9 GCIF79 @C75@=N5H=CB F9GI@HG 6IH H<=G 9::97H
=G 7CAACB HC 5@@ 5@;CF=H<AG 5B8 =G BCH GHI8=98 =B H<=G D5D9F
.C AC89@ 9LH9B898 GCIF79G K9 7CBG=89F 5 79FH5=B BIA69F C: D5H7<9G
CB H<9 @9:H <9A=GD<9F9 #: BCH GH5H98 CH<9FK=G9 H<9 D5H7<9G 5F9 7CA
DCG98 C:  58>579BH ;F=8 8=DC@9G 7CFF9GDCB8=B; HC 5B 5F95 C: 5DDFCL
=A5H9@M  7AZ C: 57H=J9 7CFH9L 5G F9EI=F98 =B CF89F HC C6H5=B 5 G=;B5@
C: GI:S7=9BH 5AD@=HI89 HC 69 A95GIF56@9 CB H<9 G75@D 577CF8=B; HC DF9
J=CIG GHI8=9G '=?IB= 9H 5@  )=G<= 9H 5@  -<=;9HC 9H 5@
 !5J5F9H 9H 5@  .5C 9H 5@  '9F@9H 5B8 !CHA5B 
69FGC@9 .<9 G<5D9G C: H<9G9 D5H7<9G <5J9 699B 7<CG9B HC :C@@CK
H<9 GI@7= 5B8 ;MF= C: H<9 7CFH9L 5B8 HC 69 8=::9F9BH :FCA H<9 7=F7I@5F
G<5D9 H<5H =G IG98 =B H<9 8=7H=CB5FM C: DCH9BH=5@ 8=GHF=6IH98 GCIF79G IB
89F@M=B; H<9 -.10 5B8 L-C'/-# 5@;CF=H<AG .C ;9B9F5H9 H<9
GCIF79 8MB5A=7G K9 IG9 5B 9D=@9DH=7 GD=?9 G=;B5@ 7CADF=G=B; %
H=A9 G5AD@9G 5H  "N G5AD@=B; :F9EI9B7M H<5H K5G G9;A9BH98 :FCA
GH9F9CH57H=7 ! -! F97CF8=B;G C: 5 D5H=9BH GI::9F=B; :FCA 9D=@9DGM
=::9F9BH F95@=N5H=CBG C: H<=G G=;B5@ CB9 :CF 957< D5H7< 8=DC@9 5F9 H<9B
7F95H98 6M =BHFC8I7=B; GA5@@ J5F=5H=CBG =B 5AD@=HI89 5B8 89@5M 'CF9
DF97=G9@M 5 J5F=5H=CB C: H<9 H9AD@5H9 G=;B5@ :; =G ;9B9F5H98 5G
K<9F9 )=G F5B8CA@M 8F5KB :FCA H<9 @C;BCFA5@ 8=GHF=6
IH=CB 5B8 τ=G F5B8CA@M 8F5KB :FCA H<9 BCFA5@ 8=GHF=6I
H=CB CF AI@H=D5H7< G79B5F=CG K9 5GGIA9 H<5H D5H7<9G 5F9 57
H=J5H98 8I9 HC 5 DFCD5;5H=CB C: H<9 9D=@9DH=7 57H=J=HM C: H<9 SFGH D5H7<
.<9F9:CF9 K9 IG9 H<9 G5A9 G=;B5@G :CF H<9 8=DC@9G C: H<9G9 G97CB85FM
D5H7<9G 6IH =BHFC8I79 5 89@5M C:  AG 89D9B8=B; CB H<9 8=GH5B79
HC H<9 SFGH D5H7< @@ GCIF79 8=DC@9G H<5H 8C BCH 69@CB; HC 5 D5H7< 5F9
5HHF=6IH98 N9FCA95B !5IGG=5B 657?;FCIB8 57H=J=HM K=H< 5B 5AD@=HI89
H<5H =G 58>IGH98 HC H<9 5AD@=HI89 C: H<9 -! G=;B5@G 69HK99B 9D=@9DH=7
GD=?9G H<IG @958=B; HC F95@=GH=7 -=;B5@ HC (C=G9 ,5H=CG -(, GI7< H<5H
 $6<9+- 14)/15/
.<9 ! 85H5 5F9 GD5H=5@@M DF9K<=H9B98 69:CF9 5DD@M=B; H<9 GCIF79
@C75@=N5H=CB 5@;CF=H<AG .C H<=G 9B8 5B 9GH=A5H9 C: H<9 BC=G9 7CJ5F=
5B79 A5HF=L =G 9AD@CM98 K<=7< =G 89F=J98 65G98 CB H<9 J5F=5B79 5B8
H<9 GD5H=5@ 7CFF9@5H=CB GHFI7HIF9 C: H<9 657?;FCIB8 57H=J=HM .C 58>IGH
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
H<9 F9;I@5F=N5H=CB D5F5A9H9F λ :CF G=B;@9 D5H7< G79B5F=CG K9 9AD@CM
H<9 B9K G9@97H=CB GHF5H9;M DF9G9BH98 =B -97H=CB  6975IG9 H<9 BC=G9
@9J9@ 65G98 G9@97H=CB GHF5H9;M 8C9G BCH KCF? :CF GA5@@ D5H7<9G K<9F9
=H =G J9FM 8=:S7I@H HC SB8 5 D5F5A9H9F λH<5H M=9@8G 5 F97CBGHFI7H=CB
9FFCF =B H<9 ;=J9B =BH9FJ5@ CF AI@H=D5H7< G79B5F=CG K9 9AD@CM H<9
BC=G9 @9J9@ 65G98 F9;I@5F=N5H=CB GHF5H9;M 6975IG9 H<9 DFCDCG98 GHF5H9;M
65G98 CB H<9 ZBCFA H9B8G HC M=9@8 HCC GD5FG9 GCIF79 9GH=A5H9G =B GCA9
75G9G 9@=A=B5H=B; D5FH C: H<9 9GH=A5H98 D5H7<9G #: BCH GH5H98 CH<9FK=G9
K9 7CBG=89F HKC SL98 J5@I9G :CF H<9 G97CB8 F9;I@5F=N5H=CB D5F5A9H9F
R   @958=B; HC GC@IH=CBG 9EI=J5@9BH HC 0- 5B8 R   69
75IG9 K9 :CIB8 H<5H H<=G @958G HC F95GCB56@9 F9GI@HG :CF H<9 7CBG=89F98
G79B5F=CG
CF -#--3 5B8 7&),. K<=7< DFCJ=89 CB9 GCIF79 9GH=A5H9 D9F H=A9
G5AD@9 K9 89H9FA=B9 H<9 57H=J9 D5H7<9G 6M H<F9G<C@8=B; H<9 GCIF79 9GH=
A5H9G 5H H<9 85H5 G5AD@9 C: A5L=A5@ DCK9F 7CFF9GDCB8=B; HC H<9 A5L=
AIA C: H<9 9D=@9DH=7 GD=?9 CF 957< =89BH=S98 GCIF79 F9;=CB 7CADF=G98
C: 58>579BH 8=DC@9G K9 H<9B 7CADIH9 H<9 5J9F5;9 C: H<9 H=A9 G=;B5@G C:
5@@ =BJC@J98 GCIF79 8=DC@9G =B CF89F HC C6H5=B CB9 9GH=A5H98 H=A9 G=;B5@
D9F D5H7< CF L-C'/-# 5B 9GH=A5H9 C: H<9 D5H7< G=;B5@G =G 7CA
DIH98 5G  "9F9 HZ 89BCH9G H<9 DG9I8C=BJ9FG9 C: H<9 GD5H=5@
A=L=B; A5HF=L ",(Y, K<CG9 9H< 7C@IAB 7CFF9GDCB8G HC H<9 GIA C:
H<9 @958 S9@8 J97HCFG 5GGC7=5H98 HC H<9 8=DC@9G 69@CB;=B; HC H<9 9H< 9G
H=A5H98 D5H7< (C :IFH<9F DFC79GG=B; =G B979GG5FM =B 75G9 C: -.10
5G H<=G 5@;CF=H<A 5@F958M DFCJ=89G 5 H=A9 G=;B5@ :CF 957< 9GH=A5H98 9L
H9B898 GCIF79 5H =HG CIHDIH
 =)3<);165 +91;-91)
.<9 D9F:CFA5B79 C: H<9 GCIF79 =A5;=B; F9GI@HG =G 5GG9GG98 IG=B; H<9
=DC@9 &C75@=N5H=CB FFCF & 35C 5B8 9K5@8  K<=7< 7<5F57
H9F=N9G H<9 G=A=@5F=HM 69HK99B H<9 CF=;=B5@ 5B8 H<9 9GH=A5H98 GCIF79 7CB
S;IF5H=CBG #: 5B8 89BCH9 H<9 CF=;=B5@ 5B8 9GH=A5H98 G9HG C: =B8=79G
C: 5@@ 8=DC@9G 69@CB;=B; HC 5B 57H=J9 D5H7< "5B8 5F9 H<9 BIA69FG C:
CF=;=B5@ 5B8 9GH=A5H98 57H=J9 8=DC@9G 5B8 rZ? 89BCH9G H<9 DCG=H=CB C: H<9
2H< GCIF79 8=DC@9 H<9B H<9 & =G 89SB98 5G
.<9 EI5@=HM C: H<9 9LHF57H98 G=;B5@G =G 9J5@I5H98 6M 75@7I@5H=B; H<9
7CFF9@5H=CB 7C9:S7=9BHG 69HK99B H<9 9GH=A5H98 D5H7< G=;B5@ 5B8 H<9 5J
9F5;98 G=;B5@ C: 5@@ 8=DC@9G 69@CB;=B; HC 5 D5H7< 19 H<9B 7CADIH9 H<9
A95B C: H<9 7CFF9@5H=CB 7C9:S7=9BHG :CF 5@@ D5H7<9G
 3151+)3 ,);)
.<9 :95G=6=@=HM C: -#--3 K5G H9GH98 CB 7<5BB9@ 85H5 F97CF898 =B
:CIF D5H=9BHG K=H< 9D=@9DGM .<9 G5AD@=B; F5H9 K5G  "N =B D5
H=9BHG 5B8  "N =B CB9 D5H=9BH .<IG :CF CIF 5B5@MG=G 85H5 K9F9 5@@
GI6G5AD@98 HC  "N *5H=9BHGD97=S7 <958 AC89@G K9F9 89F=J98 :CF
H<F99 D5H=9BHG 6M G9;A9BH=B; H<9 GIF:579G C: H<9 6F5=B H<9 G?I@@ 5B8
H<9 G75@D :FCA ',#G C: H<9 D5H=9BHG CF H<9G9 D5H=9BHG H<9 GCIF79 GD579
K5G 7CADCG98 C: 56CIH  8=DC@9G 7CFF9GDCB8=B; HC H<9 J9FH=79G C:
H<9 7CFH=75@ GIF:579 A9G< .<9 @958 S9@8 A5HF=79G K9F9 7CADIH98 IG
=B; H<9 ' A9H<C8 =AD@9A9BH98 =B )D9B'! !F5A:CFH 9H 5@ 
%M6=7 9H 5@  CF CB9 D5H=9BH BIA69F  H<9 ',# 7CI@8 CB@M 69
D5FH=5@@M G9;A9BH98 6IH G=B79 H<9F9 K5G BC @9G=CB K9 IG98 H<9 H9A
D@5H9 <958 AC89@ H<5H K5G 9AD@CM98 :CF H<9 G=AI@5H=CBG CF 957< D5
H=9BH GD=?9G K9F9 75H9;CF=N98 577CF8=B; HC H<9=F JC@H5;9 8=GHF=6IH=CB
5B8 5J9F5;98 CF D5H=9BH  K9 5B5@MN98 H<9 5J9F5;9 C:  GD=?9G H<5H
5F9 A5L=A5@ CB 9@97HFC89 . :CF D5H=9BH  K9 7CBG=89F98 H<9 5J9F
5;9 C: GD=?9G A5L=A5@ CB 9@97HFC89 . :CF D5H=9BH  K9 5B5@MN98
H<9 5J9F5;9 C:  GD=?9G A5L=A5@ CB 9@97HFC89 **)N 5B8 :CF D5H=9BH 
K9 7CBG=89F98 H<9 5J9F5;9 C: GD=?9G A5L=A5@ CB 9@97HFC89 . *5
H=9BH  <58 5@F958M IB89F;CB9 5 DF9J=CIG GIF;9FM K<9F9 D5FH C: H<9 @9:H
C77=D=H5@ 7CFH9L <58 699B F9ACJ98 6IH GH=@@ K5G BCH G9=NIF9:F99 #B
HF57F5B=5@ -! F97CF8=B;G K9F9 57EI=F98 :CF 5@@ D5H=9BHG 5G D5FH C: H<9
DF9GIF;=75@ 9J5@I5H=CB .<9 -! 85H5 K9F9 5B5@MN98 6M 5B 9LD9FH F9
GI@H=B; =B GHFCB; <MDCH<9G9G CB H<9 6F5=B F9;=CBG =BJC@J98 =B H<9 =BH9F
=7H5@ 9D=@9DH=7 57H=J=HM .<9G9 85H5 5F9 GIAA5F=N98 =B =; 
.<9 DFCDCG98 A9H<C8 K5G H<9B 5DD@=98 HC H<9 9D=@9DH=7 GD=?9G C:
H<9 :CIF D5H=9BHG 5B8 H<9 F9GI@HG K9F9 7CAD5F98 HC H<CG9 C: 7&),.
-.10 5B8 L-C'/-# CF -#--3 H<9 F9;I@5F=N5H=CB D5F5A9H9F
K5G 7<CG9B IG=B; H<9 DFCDCG98 7F=H9F=CB 65G98 CB H<9 ZBCFA 5B8 H<9
@C75@=N98 6F5=B F9;=CBG K9F9 89@=B95H98 IG=B; . K<9F95G :CF 7&),.
-.10 5B8 L-C'/-# H<9 57H=J9 GCIF79 F9;=CBG K9F9 G9@97H98
65G98 CB H<9 ;CC8B9GGC:SH !)  G99 9; 97?9F 9H 5@ 7 =
B5@@M H<9 GCIF79 @C75@=N5H=CB F9GI@HG C: H<9 8=::9F9BH H9GH98 5@;CF=H<AG
K9F9 7CAD5F98 HC H<9 SB8=B;G C: H<9 -! 5B5@MG=G
3. Results
 $15/3-7);+0 :+-5)916:
#B CF89F HC 5B5@MN9 H<9 =BTI9B79 C: H<9 F9;I@5F=N5H=CB D5F5A9H9F
αCB H<9 D9F:CFA5B79 C: H<9 -#--3 5@;CF=H<A K9 7CBG=89F  D5H7<9G
5H 8=::9F9BH DCG=H=CBG 5B8 C: J5FM=B; G=N9G :FCA  ;F=8 8=DC@9G 56CIH
 7AZ HC  ;F=8 8=DC@9G 56CIH  7AZ .<9 D5H7<9G 5F9 @C75H98
CB H<9 =B:9F=CF D5F=9H5@ ;MFIG #B:*5 H<9 GID9F=CF :FCBH5@ ;MFIG -ID F
H<9 GID9F=CF C77=D=H5@ ;MFIG -ID)77 H<9 65G5@ H9ADCF5@ ;MFIG 5G.9
5B8 H<9 A=8H9ADCF5@ ;MFIG '=8.9 .<9 & J5@I9G C6H5=B98 :CF H<9G9
D5H7<9G 5F9 G<CKB =B =; :CF G=L 8=::9F9BH J5@I9G C: H<9 D5F5A9H9F α
     5B8  5B8 :CF G=L 8=::9F9BH D5H7< G=N9G  
   5B8  D5H7< 8=DC@9G .C =ADFCJ9 H<9 F9GC@IH=CB C: H<9
GA5@@ & J5@I9G K9 <5J9 @=A=H98 H<9 7C@CF G75@9 HC 5 A5L=AIA & C:
 AA K<=7< A95BG H<5H & J5@I9G 9L7998=B; H<=G H<F9G<C@8 5F9 F9D
F9G9BH98 5G  AA =B H<9 S;IF9 #B 5BM 75G9 H<9 GCIF79 F97CBGHFI7H=CBG
7CFF9GDCB8=B; HC & J5@I9G C:  AA 5B8 ACF9 75B 69 7CBG=89F98 HC
69 =B5779DH56@9 GI7< H<5H H<9 9L57H & J5@I9 =G C: BC DF57H=75@ =ADCF
H5B79
G =; G<CKG :CF GA5@@ D5H7< G=N9G H<9 & J5@I9G 5F9 J9FM <=;<
'CF9 D5FH=7I@5F@M :CF H<9 GID9FS7=5@ D5H7<9G #B:*5 -ID F 5B8 -ID)77
5 A=B=A5@ D5H7< G=N9 C:  8=DC@9G 7CFF9GDCB8=B; HC 56CIH  7AZ C:
7CFH9L =G F9EI=F98 HC M=9@8 577IF5H9 @C75@=N5H=CB F9GI@HG K<9F95G :CF H<9
@5H9F5@ D5H7< '=8.9 5B8 H<9 899D9F D5H7< 5G.9 H<9 D5H7<9G B998 HC 69
7CADCG98 C: 5H @95GH  8=DC@9G 7CFF9GDCB8=B; HC 56CIH  7AZ C: 7CF
H9L 6CJ9 H<9 A=B=A5@ G=N9 H<F9G<C@8 H<9 & G@=;<H@M =B7F95G9G K=H<
5I;A9BH=B; D5H7< G=N9
CB79FB=B; H<9 =BTI9B79 C: H<9 F9;I@5F=N5H=CB D5F5A9H9F K<=@9 H<9
GCIF79 9GH=A5H9G 7<5B;9 CB@M G@=;<H@M K=H< GA5@@ J5F=5H=CBG C: H<9 D5F5
A9H9F α H<9 & J5@I9G ;9B9F5@@M =B7F95G9 K=H< =B7F95G=B; α GI7< H<5H
H<9 69GH F9GI@HG 5F9 57<=9J98 :CF R   CF R   .<9F9:CF9 K9 7CB
G=89F CB@M H<9 @5HH9F HKC J5@I9G =B H<9 :C@@CK=B;
 <3;17);+0 :+-5)916:
#B H<=G G97H=CB K9 7CBG=89F  8=::9F9BH G79B5F=CG
-79B5F=C  H<F99 D5H7<9G K=H< A98=IA HC @5F;9 8=GH5B79G @C75H98 CB
H<9 GID9F=CF :FCBH5@ -ID F =B:9F=CF :FCBH5@ #B: F 5B8 GID9F=CF C7
7=D=H5@ -ID)77 ;MFIG
-79B5F=C  H<F99 7@CG9 D5H7<9G @C75H98 CB H<9 A=8 H9ADCF5@ '=8.9
C77=D=H5@ H9ADCF5@ )77.9 5B8 =B:9F=CF D5F=9H5@ #B:*5 ;MFIG
-79B5F=C  :CIF 7@CG9 D5H7<9G )77.9 '=8.9 -ID)77 #B:*5
-79B5F=C  SJ9 7@CG9 D5H7<9G )77.9 '=8.9 #B:*5 -ID.9 GID9F=CF
H9ADCF5@ ;MFIG 5B8 -ID)77
=FGH C: 5@@ K9 =@@IGHF5H9 =B =; H<9 8=::9F9BH GH9DG C: H<9 . DFC79
8IF9 :CF H<9 G97CB8 G79B5F=C D5H7<9G '=8.9 )77.9 5B8 #B:*5 #B H<9
SFGH GH9D H<9 K5H9FG<98 HF5BG:CFA D9FA=HG HC =89BH=:M 5 @5F;9 BIA69F
C: F9;=CBG  =B H<=G 9L5AD@9 GI7< H<5H H<9 5AD@=HI89G C: H<9 8=DC@9G
69@CB;=B; HC 957< F9;=CB 5F9 5DDFCL=A5H9@M =89BH=75@ #B H<9 G97CB8
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 1. -IAA5FM C: H<9 -! 5B5@MG9G C: H<9 :CIF D5H=9BHG (CH9 H<5H H<9 -! F9GI@HG 7CB79FB=B; H<9 =BH9F=7H5@ 9D=@9DH=7 57H=J=HM F9DCFH98 <9F9 5F9 H<CG9 H<5H 7CFF9GDCB8 69GH HC H<9
HCDC;F5D<M C: GD=?9G F97CF898 8IF=B; H<9 G75@D ! G9GG=CB .<9 SB8=B;G C: H<9 -! 5F9 =@@IGHF5H98 :CF 957< D5H=9BH CB H<9 D5H=9BHGD97=S7 A9G< =B7@I8=B; :CF D5H=9BH  K<9F9 H<9
7CFH=75@ GIF:579 7CI@8 69 G9;A9BH98 :FCA H<9 ',# 6IH BCH H<9 7CAD@9H9 <958 AC89@ K=H< 5 @5H9F5@ G9A=@5H9F5@ G<CK=B; H<9 =BGI@5 CF A9G=5@ J=9K 89D9B8=B; CB H<9 D5H=9BH .<9 F98
DC=BHG A5F? H<9 DF=A5FM =BH9F=7H5@ 57H=J=HM H<9 CF5B;9 DC=BHG =B8=75H9 DFCD5;5H98 =BH9F=7H5@ 57H=J=HM 5B8 H<9 6@I9 DC=BHG A5F? H<9 F9;=CBG H<5H <5J9 699B 5B5@MN98 6M -! 6IH 8C BCH
G<CK 5BM G=;B=:=75BH =BH9F=7H5@ 57H=J=HM  CF =BH9FDF9H5H=CB C: H<9 F9:9F9B79G HC 7C@CF =B H<=G S;IF9 @9;9B8 H<9 F9589F =G F9:9FF98 HC H<9 K96 J9FG=CB C: H<=G 5FH=7@9
GH9D H<9G9 F9;=CBG 5F9 A9F;98 IBH=@ CB@M F9;=CBG H<5H 5F9 @C75@ A5L
=A5 CF A=B=A5 F9A5=B =B H<=G 9L5AD@9 H<=G @958G HC F9;=CBG =B5@@M
H<9 5AD@=HIH9G C: H<9 F9A5=B=B; F9;=CBG 5F9 H<F9G<C@898 =B 5 H<=F8 GH9D
M=9@8=B; 5 GCIF79 7CBS;IF5H=CB K=H< CB@M H<F99 F9;=CBG H<5H 7CFF9GDCB8
HC H<9 D5H7<9G =B H<9 CF=;=B5@ GCIF79 8=GHF=6IH=CB
(9LH K9 7CAD5F9 H<9 D9F:CFA5B79 C: 8=::9F9BH -#--3 J5F=5BHG :CF H<9
:CIF 7CBG=89F98 G79B5F=CG HC H<9 D9F:CFA5B79 C: 7&),. -.10
5B8 L-C'/-# =;  G<CKG 6CLD@CHG C: H<9 & J5@I9G C6H5=B98
CJ9F  8=::9F9BH F95@=N5H=CBG :CF 957< G79B5F=C #H 75B 69 C6G9FJ98
H<5H H<9 &G C: -#--3 :CF R   5F9 5@K5MG GA5@@9F H<5B
H<CG9 C: 7&),. -.10 5B8 L-C'/-# :CF 5@@ 7CBG=89F98 G79
B5F=CG CF R  H<=G =G 5@GC H<9 75G9 :CF G79B5F=CG 5B8  6IH BCH :CF
G79B5F=CG  5B8  CAD5F=B; H<9 F9GI@HG C: -#--3 :CF 8=::9F9BH J5@I9G
C: H<9 F9;I@5F=N5H=CB D5F5A9H9F α K9 BCH9 H<5H :CF R   =9 K=H<
588=H=CB5@ F9;I@5F=N5H=CB =B H<9 GCIF79 8CA5=B -#--3 M=9@8G GA5@@9F
&G H<5B :CF R  IFH<9FACF9 &-#--3 @958G HC GA5@@9F & H<5B
-#--3 =B D5FH=7I@5F :CF R   K<9F9 =H 5@GC F98I79G H<9 J5F=5B79 C:
H<9 C6G9FJ98 & J5@I9G 6IH :CF R   H<9 8=::9F9B79 69HK99B H<9 &
C: &-#--3 5B8 -#--3 =G F5H<9F GA5@@
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 2. =DC@9 &C75@=N5H=CB FFCF & 7C898 =B 7C@CF H<9 GA5@@9F 6@I9 H<9 69HH9F :CF 8=::9F9BH D5H7< DCG=H=CBG 89D9B8=B; CB H<9 D5H7< G=N9 5B8 H<9 F9;I@5F=N5H=CB D5F5A9H9F α (CH9
H<5H H<9 IDD9F @=A=H C: H<9 & <5G 699B SL98 HC  AA A95B=B; H<5H & J5@I9G <=;<9F H<5B H<=G H<F9G<C@8 <5J9 699B F9D@5798 6M  AA  CF =BH9FDF9H5H=CB C: H<9 F9:9F9B79G HC 7C@CF
=B H<=G S;IF9 @9;9B8 H<9 F9589F =G F9:9FF98 HC H<9 K96 J9FG=CB C: H<=G 5FH=7@9
.C ;9H 5 69HH9F =BG=;<H CB H<9 D9F:CFA5B79 C: H<9 8=::9F9BH A9H<C8G
K9 5@GC G<CK =B =;G  H<9 GCIF79 8=GHF=6IH=CBG H<5H 5F9 9GH=A5H98 6M
H<9 H9GH98 GCIF79 =A5;=B; 5@;CF=H<AG 5G K9@@ 5G H<9 H<F9G<C@898 GCIF79G
:CF H<9 8=::9F9BH -#--3 J5F=5BHG .<9G9 S;IF9G G<CK H<5H 5@@ A9H<C8G 9L
79DH 7&),. M=9@8 ;CC8 9GH=A5H9G C: H<9 H<F99 8=GH5BH D5H7<9G =B G79
B5F=C  9J9B H<CI;< L-C'/-# CJ9F9GH=A5H9G H<9 G=N9 C: H<9 D5H7<
-ID)77 "CK9J9F :CF H<9 H<F99 CH<9F G79B5F=CG H<5H =BJC@J9 G9J9F5@
7@CG9 D5H7<9G -.10 5B8 L-C'/-# 8C BCH KCF? K9@@ :5=@=B;
HC F97CJ9F 5@@ D5H7<9G @958=B; HC 658 9GH=A5H9G C: H<9 G<5D9G C: H<9
7CFF97H@M =89BH=S98 D5H7<9G 5B8 =B7@I8=B; GDIF=CIG GCIF79G :CF G79B5F
=CG 5B8  CF G79B5F=CG 5B8  H<9 GCIF79 8=GHF=6IH=CBG 9GH=A5H98
6M 7&),. G<CK <=;< 5AD@=HI89G 5H H<9 DCG=H=CBG C: H<9 D5H7<9G M9H
H<9M A5?9 =H 8=:S7I@H HC =B:9F H<9 D5H7< G=N9 5B8 G<5D9 5B8 5@GC =B
7@I89 <=;< 5AD@=HI89G 5H 5 DCG=H=CB H<5H 8C9G BCH 7CFF9GDCB8 HC 5 D5H7<
C: H<9 CF=;=B5@ GCIF79 7CBS;IF5H=CB CF G79B5F=C 5G :CF G79B5F=C 
7&),. :5=@G 7CAD@9H9@M HC F97CJ9F 5 7CFF97H GC@IH=CB CB79FB=B; H<9
D9F:CFA5B79 C: H<9 8=::9F9BH J5F=5BHG C: -#--3 K9 C6G9FJ9 H<5H :CF
R   H<9 5@;CF=H<A G<CKG GCA9 8=:S7I@H=9G =B F97CJ9F=B; 5@@ D5H7<9G
'CF9 D5FH=7I@5F@M H<9 D5H7<9G '=8.9 5B8 )77.9 K<=7< 5F9 @C75H98 =B
H<9 H9ADCF5@ @C69 5B8 H<IG <5J9 @CK9F 5AD@=HI89G 5H H<9 GIF:579 H<5B
H<9 D5H7<9G #B:*5 5B8 -ID)77 5F9 A=GG=B; =B H<9 9GH=A5H98 GCIF79 8=G
HF=6IH=CBG :CF G79B5F=CG  5B8  K<9F95G :CF G79B5F=C  H<9 5@;CF=H<A
8C9G BCH G9D5F5H9 H<9 SJ9 57H=J9 D5H7<9G LD@C=H=B; H<9 H9ADCF5@ GHFI7
HIF9 =B & -#--3 R   CB9 C6H5=BG GCA9K<5H =ADFCJ98 GCIF79 9G
H=A5H9G 6IH H<9 D9F:CFA5B79 =G 9B<5B798 ACF9 6M 7CBG=89F=B; H<9 588=
H=CB5@ F9;I@5F=N5H=CB H9FA R   .<9 69GH F9GI@HG 5F9 57<=9J98 :CF
&-#--3 K=H< R   #B H<=G 75G9 H<9 5@;CF=H<A 7CFF97H@M F97CJ9FG
5@@ D5H7<9G :CF 5@@ :CIF 7CBG=89F98 G79B5F=CG
IFH<9FACF9 =B =;  K9 5@GC G<CK H<9 9GH=A5H98 D5H7< G=;B5@G
:CF -#--3 =B 7CAD5F=GCB HC H<9 CF=;=B5@ G=AI@5H98 D5H7< 8MB5A=7G :CF
G79B5F=C  #H 75B 69 G99B H<5H -#--3 M=9@8G ;CC8 9GH=A5H9G C: H<9
GCIF79 8MB5A=7G #B D5FH=7I@5F :CF &-#--3 K=H< R   K<=7<
<5G G9D5F5H98 5@@ H<F99 D5H7<9G H<9 9GH=A5H98 D5H7< G=;B5@G G<CK H<5H
D5H7<9G )77.9 5B8 '=8.9 5F9 57H=J5H98 DF=CF HC H<9 D5H7< -ID)77 "CK
9J9F 8I9 HC H<9 GA5@@ 8=GH5B79 5B8 GA5@@ 89@5M 69HK99B H<9 G=;B5@G C:
D5H7<9G '=8.9 5B8 )77.9 H<9G9 D5H7<9G 5DD95F HC 69 G=AI@H5B9CIG@M
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 3. #@@IGHF5H=CB C: H<9 5IHCA5H=7 H<F9G<C@8=B; 5DDFC57< CF=;=B5@ GCIF79 8=GHF=6IH=CB HCD @9:H F9;=CBG =89BH=S98 6M H<9 K5H9FG<98 HF5BG:CFA =B GH9D  C: . HCD F=;<H F9A5=B=B;
F9;=CBG 5:H9F F9;=CB :IG=CB =B GH9D  C: . 6CHHCA @9:H 5B8 SB5@ F9GI@H 5:H9F H<F9G<C@8=B; C: F9;=CB 5AD@=HI89G =B GH9D  C: . 6CHHCA F=;<H
Fig. 4. CLD@CHG C: =DC@9 &C75@=N5H=CB FFCF & F9GI@HG H<9 @CK9F H<9 69HH9F C: H<9 H9GH98 GCIF79 =A5;=B; 5@;CF=H<AG :CF  8=::9F9BH AI@H=D5H7< G79B5F=CG 5B8  F95@=N5H=CBG K=H<
8=::9F9BH G=;B5@G 5B8 657?;FCIB8 57H=J=HM
57H=J5H98 =B H<9 =BJ9FG9 GC@IH=CB 5B8 H<9 GA5@@ H=A9 89@5M 75BBCH 69 F9
GC@J98 =B H<9 GCIF79 9GH=A5H=CB
+I5BH=H5H=J9@M H<9 D9F:CFA5B79 C: H<9 8=::9F9BH 5@;CF=H<AG =B 9GH=
A5H=B; H<9 GCIF79 H=A9 7CIFG9G =G 9J5@I5H98 IG=B; H<9 G=;B5@ 7CFF9@5H=CB
7C9:S7=9BHG K<=7< 5F9 ;=J9B =B .56@9  .<9 G=;B5@ 7CFF9@5H=CB 7C9:S
7=9BHG 57<=9J98 6M -#--3 5F9 7@95F@M <=;<9F H<5B H<CG9 :CF 5@@ CH<9F
A9H<C8G 'CF9CJ9F H<9 7CFF9@5H=CB 69HK99B H<9 CF=;=B5@ G=;B5@G 5B8
H<CG9 9LHF57H98 6M &-#--3 =G ;9B9F5@@M <=;<9F H<5B :CF H<9 G=;B5@G 9G
H=A5H98 6M -#--3 .<9 <=;<9GH 7CFF9@5H=CB 7C9:S7=9BHG 5F9 57<=9J98 6M
&-#--3 :CF R  
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 5. *5H7<9G -ID F #B: F 5B8 -ID)77 G79B5F=C  =BJ9FG9 GC@IH=CBG C: 7&),. -.10 5B8 L-C'/-# 5B8 9GH=A5H98 GCIF79 8=GHF=6IH=CBG 5B8 H<F9G<C@898 GCIF79G :CF :CIF
J5F=5BHG C: -#--3
=B5@@M HC ;=J9 H<9 F9589F 5B =895 C: H<9 7CADIH5H=CB5@ 7CAD@9L
=HM C: H<9 8=::9F9BH 7CBG=89F98 GCIF79 =A5;=B; A9H<C8G K9 =B8=75H9 H<9
*/ H=A9G C: H<9 5@;CF=H<AG =B .56@9  CF 7CAD5F=GCB K9 5@GC DFC
J=89 H<9 */ H=A9 C: H<9 CF=;=B5@ 0- 5@;CF=H<A .<9 5@;CF=H<AG
5F9 =AD@9A9BH98 =B '5H@565 CB 5 7CADIH9F K=H< 5  !"N #B
H9@ CF9 = DFC79GGCF 5B8  ! C: ,' (CH9 <CK9J9F H<5H D5FHG C:
L-C'/-# 5F9 =AD@9A9BH98 =B  GI7< H<5H =HG */ H=A9 =G BCH 8=
F97H@M 7CAD5F56@9 HC H<5H C: H<9 CH<9F A9H<C8G CF 5@;CF=H<AG H<5H 75B
KCF? CB 5 G=B;@9 H=A9 G5AD@9 GI7< 5G 7&),. -#--3 5B8 0-
K9 =B8=75H9 H<9 */ H=A9 =: H<9 5@;CF=H<A =G 5DD@=98 HC CB9 H=A9 G5AD@9
K<9F95G :CF -.10 L-C'/-# 5B8 &-#--3 5@@  H=A9 G5A
D@9G 5F9 DFC79GG98 6M H<9 5@;CF=H<AG .<9 GA5@@9GH */ H=A9 =G F9EI=F98
6M 7&),. :C@@CK98 6M -#--3 K<=7< H5?9G 56CIH  G 5B8 K<=7< =G
AI7< :5GH9F H<5B 0- 6M 5 :57HCF C: 56CIH  .5?=B; =BHC 577CIBH
5@@ H=A9 G5AD@9G FIBB=B; &-#--3 H5?9G 56CIH  A=B K<9F95G 9L97IH
=B; -.10 H5?9G  G @CB;9F A5?=B; =H H<9 G@CK9GH C: 5@@ H9GH98 5@;C
F=H<AG
 !);+0 :-7)9);165
#B H<=G G97H=CB K9 5=A 5H 5B5@MN=B; ACF9 DF97=G9@M H<9 F9GC@IH=CB C:
H<9 7CBG=89F98 GCIF79 =A5;=B; 5@;CF=H<AG =9 H<9 75D56=@=HM HC G9D5
F5H9 HKC D5H7<9G 89D9B8=B; CB H<9=F 8=GH5B79 .C H<=G 9B8 K9 7CBG=89F 
D5H7<9G C: G=A=@5F :CFA 7: =;  5B8 8=::9F9BH 8=GH5B79G G H<9 G9D
5F5H=CB C: H<9 D5H7<9G 8C9G BCH CB@M 89D9B8 CB H<9=F 8=GH5B79 6IH 5@GC
CB H<9=F DCG=H=CB K9 GHI8M G9J9F5@ G79B5F=CG :CF 957< 8=GH5B79
8=GH5B79  P 7A *  * *  * *  * *  * 5B8 * 
*
8=GH5B79  P 7A *  * *  * *  * 5B8 *  *
8=GH5B79  P 7A *  * *  * 5B8 *  *
8=GH5B79  P 7A *  * 5B8 *  *
UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 6. *5H7<9G '=8.9 )77.9 5B8 #B:*5 G79B5F=C  =BJ9FG9 GC@IH=CBG C: 7&),. -.10 5B8 L-C'/-# 5B8 9GH=A5H98 GCIF79 8=GHF=6IH=CBG 5B8 H<F9G<C@898 GCIF79G :CF :CIF
J5F=5BHG C: -#--3
Fig. 7. *5H7<9G )77.9 '=8.9 -ID)77 5B8 #B:*5 G79B5F=C  =BJ9FG9 GC@IH=CBG C: 7&),. -.10 5B8 L-C'/-# 5B8 9GH=A5H98 GCIF79 8=GHF=6IH=CBG 5B8 H<F9G<C@898 GCIF79G
:CF :CIF J5F=5BHG C: -#--3
19 7CBG=89F HKC D5H7<9G HC 69 G9D5F5H98 =: H<9 9GH=A5H98 GCIF79
7CBS;IF5H=CB 7CBH5=BG HKC D5H7<9G GI7< H<5H CB9 9GH=A5H98 D5H7< CJ9F
@5DG K=H< H<9 SFGH CF=;=B5@ D5H7< 5B8 H<9 CH<9F 9GH=A5H98 D5H7< CJ9F
@5DG K=H< H<9 G97CB8 CF=;=B5@ D5H7< M 5B5@MN=B;  8=::9F9BH F95@=N5
H=CBG :CF 957< G79B5F=C K9 89H9FA=B9 H<9 DFC656=@=HM C: F9GC@IH=CB 5G
H<9 D9F79BH5;9 C: F95@=N5H=CBG :CF K<=7< H<9 D5H7<9G 5F9 G9D5F5H98 57
7CF8=B; HC H<9 56CJ9 7F=H9F=CB .<9 DFC656=@=HM C: F9GC@IH=CB =G H<9B 5J
9F5;98 CJ9F 5@@ G79B5F=CG 5GGC7=5H98 K=H< 5 ;=J9B D5H7< 8=GH5B79 .<9
F9GI@H=B; DFC656=@=H9G C: F9GC@IH=CB 5F9 @=GH98 =B .56@9  :CF 957< 8=G
H5B79 5B8 957< C: H<9 9L5A=B98 GCIF79 @C75@=N5H=CB 5@;CF=H<AG IF
H<9FACF9 .56@9  G<CKG H<9 7CFF9GDCB8=B; & J5@I9G G 75B 69 9L
D97H98 H<9 DFC656=@=HM C: F9GC@IH=CB ;9B9F5@@M =B7F95G9G K=H< =B7F95G
=B; D5H7< 8=GH5B79 K<=@9 H<9 & 897F95G9G CF 8=GH5B79  H<9 D5H7<9G
5F9 IGI5@@M BCH F9GC@J98 6IH 8I9 HC H<9=F DFCL=A=HM H<9 & J5@I9G 5F9
GA5@@9F H<5B :CF 8=GH5B79  CF  1=H< -#--3 5B8 5 D5F5A9H9F R  
 H<9 D5H7<9G 75B 69 G9D5F5H98 =B 5@ACGH 5@@ 75G9G :CF 8=GH5B79  CF
<=;<9F IFH<9FACF9 -#--3 :95HIF9G <=;<9F DFC656=@=H=9G C: F9GC@IH=CB
5B8 @CK9F & J5@I9G H<5B -.10 5B8 L-C'/-# =B D5FH=7I@5F
:CF R   J9B H<CI;< H<9 DFC656=@=HM C: F9GC@IH=CB =G GCA9H=A9G

UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 8. *5H7<9G )77.9 '=8.9 #B:*5 -ID.9 5B8 -ID)77 G79B5F=C  =BJ9FG9 GC@IH=CBG C: 7&),. -.10 5B8 L-C'/-# 5B8 9GH=A5H98 GCIF79 8=GHF=6IH=CBG 5B8 H<F9G<C@898
GCIF79G :CF :CIF J5F=5BHG C: -#--3
Table 1
J9F5;9 G=;B5@ 7CFF9@5H=CB 7C9:S7=9BH 69HK99B CF=;=B5@ D5H7< G=;B5@G 5B8 9GH=A5H98 D5H7<
G=;B5@G
G=;B5@7CFF9@5H=CB

G79B5F=C
G79B5F=C
G79B5F=C
G79B5F=C
7&),.    
-.10    
L-C'/-#    
&-#--3 R    
&-#--3 R    
&-#--3
R
   
&-#--3
R
   
Table 2
'95B */ H=A9 5J9F5;98 CJ9F H<9  G79B5F=CG
5@;CF=H<A */H=A9=B
G97CB8G
5@;CF=H<AGKCF?=B;CB5H=A9G5AD@9
6MG5AD@965G=G
7&),. 
&-#--3
R

&-#--3
R

0- 
5@;CF=H<AGH5?=B;=BHC577CIBH5@@H=A9
G5AD@9G
-.10 
L-C
'/-#

&-#--3
R

&-#--3
R

69HH9F :CF 7&),. H<9 & J5@I9G 5F9 7CBG=89F56@M <=;<9F H<5B :CF
-#--3 K<=7< A95BG H<5H H<9 CJ9F5@@ GCIF79 G9D5F5H=CB 5B8 @C75@=N5H=CB
:CF H<9 7CBG=89F98 G79B5F=CG =G 69GH K<9B IG=B; -#--3 K=H< R  
Fig. 9. -=L D5H7<9G 7CBG=89F98 :CF H<9 5B5@MG=G C: D5H7< G9D5F5H=CB
Table 3
J9F5;9 DFC656=@=HM C: F9GC@IH=CB :CF 957< GCIF79 @C75@=N5H=CB 5@;CF=H<A 5B8 :CF :CIF 8=:
:9F9BH D5H7< 8=GH5B79G
DFC656=@=HMC:
F9GC@IH=CB
8=GH5B79
8=GH5B79
8=GH5B79
8=GH5B79
7&),.    
-.10    
L-C'/-#    
&-#--3 R    
&-#--3 R    
&-#--3
R
   
&-#--3
R
   
Table 4
J9F5;9 & :CF 957< GCIF79 @C75@=N5H=CB 5@;CF=H<A 5B8 :CF :CIF 8=::9F9BH D5H7< 8=GH5B79G
&AA 8=GH5B79
8=GH5B79
8=GH5B79
8=GH5B79
7&),.    
-.10    
L-C'/-#    
&-#--3 R    
&-#--3 R    
&-#--3
R
   
&-#--3
R
   

UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
 3151+)3 ,);)
#B CF89F HC GHI8M H<9 DFCD5;5H=CB D<9BCA9B5 H<5H A5M DCH9BH=5@@M
C77IF 8IF=B; H<9 =BH9F=7H5@ GD=?9G C: H<9 7@=B=75@ 85H5 K9 <5J9 GMGH9A5H=
75@@M 5DD@=98 H<9 H9GH98 GCIF79 =A5;=B; 5@;CF=H<AG HC HKC H=A9 =BH9FJ5@G
7CFF9GDCB8=B; HC H<9 SFGH B9;5H=J9 K5J9 C: H<9 GD=?9 H=A9 =BH9FJ5@ 
5B8 HC H<9 GI6G9EI9BH DCG=H=J9 K5J9 H=A9 =BH9FJ5@  7: =;  CF
ACGH D5H=9BHG H<9 GCIF79 @C75@=N5H=CB F9GI@HG K9F9 GH56@9 CJ9F 6CH< H=A9
=BH9FJ5@G 5B8 K9 CB@M C6G9FJ98 5 DFCD5;5H=CB C: H<9 9D=@9DH=7 GD=?9 :CF
D5H=9BH  .<9F9:CF9 :CF D5H=9BH  K9 G<CK H<9 F9GI@HG :CF 6CH< H=A9
=BH9FJ5@G K<9F95G :CF H<9 CH<9F D5H=9BHG K9 CB@M 8=GD@5M H<9 F9GI@HG C6
H5=B98 :CF H=A9 =BH9FJ5@ 
CF D5H=9BH  GCIF79 @C75@=N5H=CB F9GI@HG C6H5=B98 K=H< H<9 8=:
:9F9BH 5@;CF=H<AG 5F9 8=GD@5M98 =B =;  7&),. -.10 5B8
L-C'/-# M=9@898 J9FM G=A=@5F F9GI@HG :CF 6CH< H=A9 =BH9FJ5@G K<=7<
=G K<M :CF H<9G9 A9H<C8G K9 CB@M G<CK H<9 GC@IH=CBG C6H5=B98 :CF H=A9
=BH9FJ5@  7&),. G<CKG <=;< 57H=J5H=CB C: H<9 F=;<H H9ADCF5@ @C69
5B8 F=;<H C77=D=H5@ 6F5=B F9;=CBG -.10 5B8 L-C'/-# =89BH=:M
5DDFCL=A5H9@M H<9 G5A9 GCIF79 F9;=CB =B H<9 F=;<H H9ADCF5@ @C69 CB
79FB=B; H<9 =89BH=S98 57H=J9 D5H7<9G H<9 :CIF H9GH98 J5F=5BHG C: -#--3
@958 HC 7CAD5F56@9 F9GI@HG GC K9 =@@IGHF5H9 CB@M H<9 F9GI@HG C: -#--3 :CF
R   5B8 :CF &-#--3 :CF R  CF H=A9 =BH9FJ5@  -#--3 =89B
H=S9G CB9 F9;=CB =B H<9 65G5@ 5GD97H C: H<9 F=;<H H9ADCF5@ DC@9 K<9F95G
:CF H=A9 =BH9FJ5@  H<9 9GH=A5H98 57H=J5H=CB =BJC@J9G H<9 DCGH9F=CF <5@:
C: H<9 F=;<H H9ADCF5@ @C69 5B8 H<9 F=;<H H9ADCFCC77=D=H5@ >IB7H=CB 7
7CF8=B; HC H<9 7@=B=75@ =BH9FDF9H5H=CB C: -! =BHF579F96F5@ 85H5 7:
=;  H<9 6F5=B F9;=CBG =BJC@J98 =B H<9 =BH9F=7H5@ 9D=@9DH=7 57H=J=HM =B
7@I89 H<9 F=;<H 65G5@ H9ADCF5@ DC@9 K=H< DCGH9F=CF 8=::IG=CB HC H<9 F=;<H
A=88@9 H9ADCF5@ @C69 .<9 GCIF79 =A5;=B; F9GI@HG C6H5=B98 6M -#--3
5B8 H<9 CH<9F H9GH98 GCIF79 =A5;=B; 5@;CF=H<AG 5F9 H<IG ACGH@M 7CB7CF
85BH K=H< H<9 SB8=B;G C: H<9 -! 5B5@MG=G "CK9J9F -.10 5B8
L-C'/-# 8C BCH G<CK H<9 57H=J5H=CB C: H<9 F=;<H H9ADCF5@ DC@9 5B8
7&),. @C75@=N9G 5@GC F=;<H C77=D=H5@ 6F5=B F9;=CBG K<=7< <5J9 BCH
699B C6G9FJ98 HC 69 =BJC@J98 =B 9D=@9DH=7 57H=J=HM =B H<9 -! F97CF8
=B;G CF 6CH< J5F=5BHG C: -#--3 K9 5@GC D@CH H<9 9GH=A5H98 H=A9 G=;
B5@G K=H<=B HKC G998 D5H7<9G 7CADF=G=B; 5DDFCL=A5H9@M  7AZ C: 7CFH9L
5B8 @C75H98 CB H<9 H9ADCF5@ DC@9 5B8 =B H<9 DCGH9F=CF H9ADCF5@ 7CFH9L
G99 =;  6CHHCA 79BH9F .<9G9 HKC D5H7<9G @=9 K=H<=B H<9 HKC 6F5=B
F9;=CBG =89BH=S98 6M -#--3 :CF H<9 HKC 7CBG=89F98 H=A9 =BH9FJ5@G =;
 6CHHCA G<CKG H<5H H<9 G=;B5@ C: H<9 H9ADCF5@ DC@9 =G 7<5F57H9F=N98
6M 5 <=;< B9;5H=J9 5AD@=HI89 =B H<9 SFGH H=A9 =BH9FJ5@ 7CFF9GDCB8=B; HC
H<9 A=B=AIA C: H<9 9D=@9DH=7 GD=?9 .<9 D5H7< =B H<9 DCGH9F=CF H9ADCF5@
@C69 5@GC <5G B9;5H=J9 5AD@=HI89 5H H<9 A=B=AIA C: H<9 GD=?9 6IH H<9
5AD@=HI89 =G AI7< GA5@@9F H<5B =B H<9 H9ADCF5@ DC@9 K<=7< 9LD@5=BG
K<M H<=G 57H=J5H=CB =G BCH J=G=6@9 =B H<9 H<F9G<C@898 -#--3 GC@IH=CB :CF
H=A9 =BH9FJ5@  CF H=A9 =BH9FJ5@  H<9 DCG=H=J9 K5J9 C: H<9 9D=@9DH=7
GD=?9 =G G@=;<H@M ACF9 DFCBCIB798 =B H<9 DCGH9F=CF H9ADCF5@ @C69 K=H<
5 GCA9K<5H <=;<9F 5AD@=HI89 5B8 @CB;9F 8IF5H=CB CAD5F=B; H<9 G=;
B5@G 9GH=A5H98 6M H<9 HKC J5F=5BHG C: -#--3 =H 75B 69 G99B H<5H :CF -#--3
K=H< R   H<9 G=;B5@G :95HIF9 GCA9 GA5@@ TI7HI5H=CBG 5B8 5F9 BCH 5@
K5MG H<9 G5A9 :CF H<9 8=DC@9G K=H<=B 957< D5H7< .<9 G=;B5@G 9LHF57H98
6M &-#--3 5F9 GACCH<9F 5B8 H<IG GCA9K<5H 95G=9F HC =BH9FDF9H 8I9 HC
H<9 9LD@C=H5H=CB C: H9ADCF5@ GHFI7HIF9 =B H<9 5@;CF=H<A
CF D5H=9BHG  K9 =@@IGHF5H9 =B =;  H<9 GCIF79 @C75@=N5H=CB F9
GI@HG C6H5=B98 K=H< -#--3 :CF R   5B8 &-#--3 :CF R   6CH<
5:H9F . =B 7CAD5F=GCB HC H<9 =BJ9FG9 GC@IH=CBG C: 7&),. -.10
5B8 L-C'/-# CF D5H=9BH  -#--3 5B8 7&),. @C75@=N9 H<9
Fig. 10. @=B=75@ 85H5 C: D5H=9BH  -CIF79 @C75@=N5H=CB C6H5=B98 :CF 9D=@9DH=7 GD=?9G A5L=A5@ CB 9@97HFC89 . .<9 HKC 7CBG=89F98 H=A9 =BH9FJ5@G 7CFF9GDCB8=B; HC H<9 SFGH 5B8 G97CB8
D5FH C: H<9 GD=?9 5F9 A5F?98 =B M9@@CK 5B8 CF5B;9 .<9 H=A9 DC=BHG CB9 K=H<=B 957< =BH9FJ5@ :CF K<=7< H<9 GCIF79 @C75@=N5H=CB F9GI@HG 5F9 8=GD@5M98 5F9 A5F?98 6M F98 8CHH98 @=B9G 5B8
7CFF9GDCB8 HC H<9 A=B=AIA 5B8 H<9 A5L=AIA C: H<9 9D=@9DH=7 GD=?9 CF 7&),. -.10 5B8 L-C'/-# K9 8=GD@5M CB@M H<9 F9GI@HG C6H5=B98 :CF H=A9 =BH9FJ5@ F9GI@HG :CF H=A9
=BH9FJ5@ 5F9 7CAD5F56@9 CF -#--3 H<9 5AD@=HI89G C: H<9 6F5=B F9;=CBG =B57H=J9 577CF8=B; HC . <5J9 699B G9H HC 5B8 :CF 7&),. H<9 5AD@=HI89G C: H<9 6F5=B F9;=CBG BCH G9@97H98
6M H<9 !) <5J9 699B G9H HC  CF -#--3 K9 5@GC 8=GD@5M H<9 9GH=A5H98 GCIF79 8MB5A=7G K=H<=B HKC G998 D5H7<9G @C75H98 K=H<=B H<9 F9;=CBG @C75@=N98 8IF=B; H<9 SFGH 5B8 G97CB8 H=A9
=BH9FJ5@ *5@9 6@I9 5B8 D5@9 ;F99B G=;B5@G G<CK 8MB5A=7G C: =B8=J=8I5@ 8=DC@9G K=H<=B 957< D5H7< K<9F95G 85F? 6@I9 5B8 85F? ;F99B G=;B5@G 7CFF9GDCB8 HC H<9 5J9F5;9 G=;B5@G C: 957< D5H7<

UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
Fig. 11. @=B=75@ 85H5 C: D5H=9BHG  -CIF79 @C75@=N5H=CB C6H5=B98 :CF 9D=@9DH=7 GD=?9G A5L=A5@ CB 9@97HFC89 . :CF D5H=9BH  CB 9@97HFC89 **)N :CF D5H=9BH  5B8 CB 9@97HFC89 . :CF
D5H=9BH  CF -#--3 H<9 5AD@=HI89G C: H<9 6F5=B F9;=CBG =B57H=J9 577CF8=B; HC . <5J9 699B G9H HC 5B8 :CF 7&),. H<9 5AD@=HI89G C: H<9 6F5=B F9;=CBG BCH G9@97H98 6M H<9 !) <5J9
699B G9H HC 
A5=B 57H=J5H=CB 5H H<9 A=B=AIA C: H<9 GD=?9 G=;B5@ CB H<9 @9:H H9ADCF5@
DC@9 &-#--3 :CF R   G<CKG 5 J9FM :C75@ 57H=J5H=CB 7&),.
M=9@8G 5 G=A=@5F GC@IH=CB 6IH H<9 =89BH=S98 6F5=B F9;=CBG 5F9 G@=;<H@M
ACF9 DCGH9F=CF -.10 @C75@=N9G 5 6F5=B F9;=CB =B H<9 @9:H =BGI@5 =
B5@@M L-C'/-# =89BH=S9G HKC D5H7<9G CB9 =B H<9 @9:H H9ADCF5@
DC@9 5B8 5BCH<9F CB9 =B H<9 @9:H =BGI@5 G F9DCFH98 =B =;  H<9 F9;=CBG
=BJC@J98 =B H<9 =BHF579F96F5@ =BH9F=7H5@ 57H=J=HM =B7@I89 H<9 @9:H H9ADCF5@
DC@9 H<9 =BGI@5 5B8 H<9 A9G=5@ 5GD97H C: H<9 @9:H H9ADCF5@ @C69 .<9 ACGH
7CB7CF85BH F9GI@H =G H<9F9:CF9 C6H5=B98 :FCA L-C'/-# 6IH -#--3
5B8 H<9 CH<9F H9GH98 5@;CF=H<AG 5F9 5@GC 56@9 HC F9HF=9J9 D5FH C: H<9 =B
H9F=7H5@ B9HKCF? =BJC@J98 8IF=B; -! F97CF8=B;G
CF D5H=9BH  H<9 HKC 7CBG=89F98 J5F=5BHG C: -#--3 @958 HC B95F@M
=89BH=75@ F9GI@HG G99 =;  A=88@9 @C75@=N=B; 5 D5H7< =B H<9 @9:H GI
D9F=CF DF97IB9IG .<9 A5L=A5@ 5AD@=HI89G 9GH=A5H98 6M 7&),. 5F9
5@GC 7CB79BHF5H98 =B H<=G 6F5=B F9;=CB 6IH =B 588=H=CB 7&),. 5@GC
G<CKG 5B 57H=J5H=CB C: H<9 F=;<H GID9F=CF DF97IB9IG 5B8 @C75@=N9G G9J
9F5@ CH<9F GA5@@ 6F5=B F9;=CBG =B C77=D=H5@ 5B8 H9ADCF5@ 5F95G C: H<9
@9:H <9A=GD<9F9 -.10 =89BH=S9G 5 @5F;9 D5H7< CB H<9 F=;<H GID9F=CF
DF97IB9IG =B5@@M L-C'/-# =89BH=S9G 5 BIA69F C: GA5@@ D5H7<9G
=B H<9 H=GGI9 F9A5=B=B; 5:H9F H<9 F9G97H=CB =B H<9 A9G=5@ 5B8 GID9F=CF
5GD97H C: H<9 C77=D=HCD5F=9H5@ F9;=CB .<9 -! F97CF8=B;G G<CK H<5H
H<9 9D=@9DH=7 GD=?9G CF=;=B5H9 :FCA H<9 6F5=B F9;=CBG 5FCIB8 H<9 F9
G97H98 5F95 5B8 :FCA H<9 DCGH9F=CF 7=B;I@5H9 ;MFIG #B D5FH=7I@5F H<9
@9:H A9G=5@ D5F=9HCC77=D=H5@ 6F5=B F9;=CBG 5B8 H<9 @9:H 65G5@ 5B8 GID9
F=CF DF97IB9IG 7: =;  5F9 DF=A5F=@M =BJC@J98 =B H<9 =BH9F=7H5@ 57H=J
=HM CF H<=G D5H=9BH H<9 GCIF79 @C75@=N5H=CB F9GI@HG C: L-C'/-# 5F9
H<IG H<9 ACGH 7CB7CF85BH K=H< H<9 -! 5B5@MG=G .<9 F9GI@HG C: -#--3
5F9 @9GG 7CB7CF85BH 6IH F9A5=B =B 69HH9F 5;F99A9BH K=H< =BHF579F96F5@
F97CF8=B;G H<5B H<CG9 C6H5=B98 6M 7&),. .<9 F9GI@HG C: -.10
8C BCH A5H7< H<9 C6G9FJ5H=CBG A589 =B H<9 -! 5B5@MG=G
#B 75G9 C: D5H=9BH  6CH< J5F=5BHG C: -#--3 @C75@=N9 5 6F5=B F9;=CB
CB H<9 F=;<H H9ADCF5@ DC@9 6IH H<=G F9;=CB =G G@=;<H@M GA5@@9F :CF &
-#--3 K=H< R   7&),. =89BH=S9G 5 @5F;9 BIA69F C: GA5@@ 6F5=B
F9;=CBG G75HH9F98 5@@ CJ9F H<9 F=;<H <9A=GD<9F9 6IH =BJC@J=B; =B D5F
H=7I@5F F=;<H A9G=5@ 5F95G -.10 5B8 L-C'/-# 6CH< G<CK 5B
57H=J5H=CB C: H<9 A9G=5@ D5FH C: H<9 F=;<H H9ADCF5@ DC@9 77CF8=B; HC
H<9 -! 5B5@MG=G H<9 6F5=B F9;=CB =BJC@J98 =B 9D=@9DH=7 GD=?9 57H=J
=HM 7CFF9GDCB8G HC H<9 5BH9F=CF D5FH C: H<9 F=;<H H9ADCF5@ @C69 A9G=5@@M
5B8 @5H9F5@@M .<=G =G 7CB7CF85BH K=H< H<9 SB8=B;G C: -#--3 -.10
5B8 L-C'/-# K<=7< F9HF=9J9 9=H<9F H<9 A9G=5@ CF H<9 @5H9F5@ 5GD97H
C: H<9 5BH9F=CF H9ADCF5@ F9;=CB K<=@9 H<9 GCIF79 @C75@=N5H=CB F9GI@H C:
7&),. 8C9G BCH A5H7< H<9 F9GI@HG :FCA H<9 =BHF579F96F5@ F97CF8=B;G
4. Discussion
1<=@9 H<9 SFGH 5@;CF=H<AG H<5H <5J9 699B DFCDCG98 :CF 6F5=B GCIF79
@C75@=N5H=CB CJ9F HKC 897589G 5;C 5F9 A5=B@M GI=H98 :CF H<9 =89BH=S75
H=CB C: :C75@ GCIF79G CJ9F H<9 D5GH :9K M95FG F9G95F7<9FG <5J9 D5=8
=B7F95G=B; 5HH9BH=CB HC H<9 =89BH=S75H=CB C: GD5H=5@@M 9LH9B898 GCIF79G
K<=7< <5G 699B H<9 HCD=7 C: G9J9F5@ DF9J=CIG GHI8=9G &=AD=H= 
F=GHCB 9H 5@  =B;  C@GH58  =FCH 9H 5@ 
<CK8<IFM 9H 5@  97?9F 9H 5@ 7 4<I 9H 5@  .<9
DFCDCG98 5@;CF=H<AG 5F9 65G98 CB 5 J5F=9HM C: 5DDFC57<9G =B7@I8=B;

UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
9LH9B898 GCIF79 G75BB=B; 5M9G=5B H9BGCF65G98 5B8 GD5FG9 A9H<C8G
1<9B 7CB:FCBH98 K=H< 85H5 C: G9J9F5@ G=AI@H5B9CIG@M 57H=J9 9LH9B898
GCIF79G H<9 0- 5@;CF=H<A <5G DFCJ98 HC 69 CB9 C: H<9 ACGH
DFCA=G=B; A9H<C8G 97?9F 9H 5@ 6  =B D5FH=7I@5F =B H<9 75G9
C: 7CFF9@5H98 57H=J=H=9G 5B8 <5G 699B GI779GG:I@@M 9AD@CM98 :CF H<9 @C
75@=N5H=CB C: 6F5=B F9;=CBG =BJC@J98 =B =BH9F=7H5@ 9D=@9DH=7 GD=?9 G=;B5@G
4<I 9H 5@ 
#B H<=G D5D9F K9 <5J9 GHF=J98 HC :IFH<9F =ADFCJ9 H<9 @C75@=N5H=CB
C: 9LH9B898 GCIF79G 6M DF9G9BH=B; 5 B9K F9;I@5F=N98 @95GH GEI5F9G 5@
;CF=H<A 75@@98 -#--3 K<=7< 6I=@8G CB H<9 0- A9H<C8 G H<9
0- 5@;CF=H<A F9;I@5F=N5H=CB CB@M 5DD@=9G HC H<9 ;F58=9BH C: H<9
GCIF79 8=GHF=6IH=CB =9 H<9 J5F=5H=CB5@ A5D K<=7< =G =BJ5F=5BH K=H< F9
GD97H HC 5B 58898 7CBGH5BH =B H<9 CF=;=B5@ GCIF79 8CA5=B =H @95J9G 5B
CD9B=B; :CF GCIF79 9GH=A5H9G H<5H 5F9 5AD@=HI896=5G98 .<=G DFC6@9A =G
GI779GG:I@@M H57?@98 6M H<9 588=H=CB5@ ZBCFA F9;I@5F=N5H=CB H9FA 9A
D@CM98 6M -#--3 "CK9J9F 5G H<9 G=B;@9D5H7< G=AI@5H=CB F9GI@HG G<CK
H<9 K9=;<H C: H<=G 588=H=CB5@ F9;I@5F=N5H=CB H9FA G<CI@8 69 @9:H GA5@@
7CAD5F98 HC H<9 K9=;<H C: H<9 J5F=5H=CB5@ A5D F9;I@5F=N5H=CB H9FA 69
75IG9 H<9 EI5@=HM C: H<9 GCIF79 9GH=A5H9G 897@=B9G K=H< =B7F95G=B; =B
TI9B79 C: H<=G H9FA .<=G =G GCA9K<5H GIFDF=G=B; 5G CB9 7CI@8 <5J9
9LD97H98 H<=G GD5FG=HM=B8I7=B; H9FA HC <9@D =89BH=:M D5H7<9G C: GA5@@
G=N9 39H H<9 G=AI@5H=CBG <5J9 G<CKB H<5H 69G=89G 5JC=8=B; H<9 5AD@=
HI896=5G H<9 B9K F9;I@5F=N5H=CB H9FA =G CB@M IG9:I@ =B H<9 7CBH9LH C:
AI@H=D@9 D5H7<9G K<9F9 =H <9@DG HC G9D5F5H9 7@CG9 D5H7<9G 5G 89ACB
GHF5H98 6M H<9 GA5@@9F & J5@I9G :CF G79B5F=CG  5B8 H<9 <=;<9F DFC6
56=@=H=9G C: D5H7< G9D5F5H=CB 6IH BCH :CF F97CJ9F=B; G=B;@9 D5H7<9G C:
GA5@@ G=N9 )B H<9 CH<9F <5B8 CIF C6G9FJ5H=CB H<5H D5H7<9G 7CADF=G=B;
@9GG H<5B  7AZ C: H<9 7CFH=75@ GIF:579 75BBCH 69 577IF5H9@M =89BH=S98
=B89D9B89BH@M C: H<9 9AD@CM98 F9;I@5F=N5H=CB GHF5H9;M =G 7CFFC6CF5H98
6M DF9J=CIG ! 5B8 '! GHI8=9G K<=7< <5J9 G<CKB H<5H 5 79FH5=B
5F95 C: 7CFH9L ;9B9F5@@M H<9 A=B=AIA 5F95 =G G5=8 HC 69  7AZ B998G
HC 69 57H=J9 HC C6H5=B 5 G=;B5@ C: GI:S7=9BH 5AD@=HI89 HC 69 A95GIF56@9
5H H<9 GIF:579 '=?IB= 9H 5@  )=G<= 9H 5@  -<=;9HC 9H 5@
 !5J5F9H 9H 5@  .5C 9H 5@  '9F@9H 5B8 !CHA5B 
69FGC@9 
C@@CK=B; )I 9H 5@  !F5A:CFH 9H 5@  K9 <5J9 5@GC 7CB
G=89F98 9LD@C=H=B; H<9 H9ADCF5@ GHFI7HIF9 C: H<9 85H5 6M F9D@57=B; H<9
ZBCFA =B H<9 F9;I@5F=N5H=CB H9FAG 6M H<9 &BCFA G H<9 G=AI@5
H=CBG G<CK H<=G 7CBG=89F56@M =ADFCJ9G H<9 9GH=A5H98 H=A9 7CIFG9G C: H<9
GCIF79G 5B8 @958G HC ACF9 FC6IGH GCIF79 9GH=A5H9G =B D5FH=7I@5F =B H<9
75G9 C: G9J9F5@ 7@CG9 D5H7<9G K<9F9 =H :57=@=H5H9G H<9 D5H7< G9D5F5H=CB
CBHF5FM HC H<9 A9H<C8 DFCDCG98 =B &=AD=H=  L-C'/-#
5B8 -.10 -#--3 =G BCH 65G98 CB 5 D5F5A9H9F=N5H=CB C: H<9 8=GHF=6
IH98 GCIF79 .<=G A5?9G =H ACF9 T9L=6@9 K=H< F9GD97H HC H<9 :CFA C:
H<9 D5H7<9G 5G =H 75B H<9CF9H=75@@M F97CJ9F 5 D5H7< C: 5BM :CFA K=H<
CIH DF9:9F9B79 :CF 7=F7I@5FG<5D98 GCIF79 F9;=CBG @=?9 L-C'/-# CF
-.10 -H=@@ K9 <5J9 C6G9FJ98 H<5H -#--3 5@GC G99AG HC <5J9 79FH5=B
DF9:9F9B79G :CF D5H7< ;9CA9HF=9G K<=7< 75BBCH 69 7<5F57H9F=N98 =B ;9B
9F5@ 5G H<9M 89D9B8 CB H<9 @C75@ 7<5F57H9F=GH=7G C: H<9 7CFH=75@ GIF:579
A9G<
 ;9B9F5@ DFC6@9A K=H< 5@;CF=H<AG 69@CB;=B; HC H<9 :5A=@M C: F9;I
@5F=N98 @95GH GEI5F9G 5DDFC57<9G =G H<9 7<C=79 C: H<9 F9;I@5F=N5H=CB D5
F5A9H9F ):H9B H<=G D5F5A9H9F =G 58>IGH98 577CF8=B; HC H<9 BC=G9 @9J9@
K<=7< B998G HC 69 9GH=A5H98 :FCA H<9 A95GIF9A9BHG 6M 5B5@MN=B; 5
GI=H56@9 85H5 =BH9FJ5@ #B H<=G D5D9F K9 <5J9 7CBG=89F98 5B 5@H9FB5
H=J9 5DDFC57< K<9F9 H<9 F9;I@5F=N5H=CB D5F5A9H9F =G CDH=A=N98 K=H< F9
GD97H HC H<9 ZBCFA 7CBGHF5=BH K<=7< A5L=A=N9G H<9 GD5FG=HM C: H<9 GC
@IH=CB .<=G GHF5H9;M KCF?G J9FM K9@@ :CF G=B;@9D5H7< G79B5F=CG "CK
9J9F =B H<9 75G9 C: AI@H=D@9 D5H7<9G H<=G 5DDFC57< H9B8G HC 9@=A=B5H9
D5H7<9G K=H< K95? 5AD@=HI89G .<9 F9;I@5F=N5H=CB D5F5A9H9F H<5H =G 5I
HCA5H=75@@M G9@97H98 IG=B; H<=G A9H<C8 G<CI@8 H<IG 69 J=9K98 5G 5 A5L
=AIA J5@I9 H<5H ;=J9G 5 ;CC8 =B8=75H=CB C: 5B 589EI5H9 D5F5A9H9F #B
DF57H=79 HC 5JC=8 CJ9F@CC?=B; K95?9F GCIF79G =H =G <CK9J9F 58J=G56@9
HC 7<97? H<9 GCIF79 8=GHF=6IH=CBG C6H5=B98 :CF GCA9K<5H GA5@@9F F9;I
@5F=N5H=CB D5F5A9H9FG (9J9FH<9@9GG GC :5F CIF 9LD9F=9B79 K=H< H<9 B9K
F9;I@5F=N5H=CB GHF5H9;M CB F95@ ! F97CF8=B;G =G DCG=H=J9
.C 89@=B95H9 H<9 GCIF79 F9;=CBG 65G98 CB H<9 GCIF79 =A5;=B; GC@I
H=CBG H<9 @5HH9F <5J9 HC 69 H<F9G<C@898 .C H<=G 9B8 K9 <5J9 DFCDCG98
HC 9AD@CM 5B . A9H<C8 65G98 CB HCC@G :FCA =A5;9 DFC79GG=B; .C CIF
?BCK@98;9 H<=G =G H<9 SFGH H=A9 H<5H 5B . A9H<C8 H<5H =G BCH 65G98 CB
5 G=AD@9 5AD@=HI89 H<F9G<C@8 =G DF9G9BH98 =B H<9 7CBH9LH C: 6F5=B GCIF79
=A5;=B; .<9 58J5BH5;9 C: H<9 DFCDCG98 5DDFC57< =G H<5H =H =G ACF9 C6
>97H=J9 H<5B G9@97H=B; 5 SL98 H<F9G<C@8 :CF H<9 8=DC@9 5AD@=HI89G G
H<9 . 5DDFC57< G9;A9BHG H<9 GCIF79 8=GHF=6IH=CB 65G98 CB H<9 ;F58=
9BH =H 5@GC D9FA=HG HC 89@=B95H9 GCIF79 F9;=CBG K<CG9 5AD@=HI89 =G CB@M
G@=;<H@M @5F;9F H<5B H<5H C: GIFFCIB8=B; ;F=8 8=DC@9G 5B8 K<=7< KCI@8
<5J9 699B J9FM 8=:S7I@H HC F97C;B=N9 IG=B; 5 SL98 5AD@=HI89 H<F9G<C@8
M 7CBHF5GH H<=G 5DDFC57< <5G GCA9 8=:S7I@H=9G =B 589EI5H9@M H<F9G<C@8
=B; GCIF79 8=GHF=6IH=CBG K=H< J9FM ;F58I5@ 5AD@=HI89 7<5B;9G 6975IG9 =B
H<=G 75G9 H<9F9 =G BC G=;B=:=75BH 7<5B;9 =B ;F58=9BH H<5H 75B 69 9LD@C=H98
:CF H<9 89@=B95H=CB C: H<9 GCIF79G "CK9J9F K=H< 5B 5DDFCDF=5H9 7<C=79
C: H<9 F9;I@5F=N5H=CB D5F5A9H9F H<=G ?=B8 C: GCIF79 8=GHF=6IH=CB G<CI@8
BCH C77IF IG=B; -#--3
CF H<9 G=AI@5H=CBG 7CB8I7H98 =B H<=G D5D9F K9 IG9 H<9 G5A9 JC@
IA9 7CB8I7HCF 5B8 GCIF79 GD579 :CF H<9 :CFK5F8 5B8 H<9 =BJ9FG9 DFC6
@9A H<9F96M B9;@97H=B; H<9 =AD57H C: AC89@=B; 9FFCFG CB H<9 GCIF79 @C
75@=N5H=CB F9GI@HG "CK9J9F H<9 AC89@=B; 9FFCFG KCI@8 =BTI9B79 H<9 F9
GI@HG C: 5@@ GCIF79 @C75@=N5H=CB 5@;CF=H<AG GI7< H<5H H<9=F B9;@=;9B79 8C9G
BCH ;=J9 5BM 58J5BH5;9 HC H<9 DFCDCG98 A9H<C8 =B D5FH=7I@5F (9J9FH<9
@9GG H<9 FC6IGHB9GG HC AC89@=B; 9FFCFG C: 8=::9F9BH GCIF79 @C75@=N5H=CB
5@;CF=H<AG =G 5B =BH9F9GH=B; GI6>97H H<5H G<CI@8 69 =BJ9GH=;5H98 =B :IHIF9
GHI8=9G
.C J5@=85H9 H<9 DFCDCG98 5@;CF=H<A CB 7@=B=75@ 85H5 K9 <5J9 7CB
G=89F98 ! F97CF8=B;G C: :CIF 9D=@9DH=7 D5H=9BHG #B 5@@ 75G9G H<9 6F5=B
F9;=CBG =89BH=S98 6M -#--3 5F9 7CB7CF85BH K=H< H<9 SB8=B;G C: 5B -!
5B5@MG=G K<=7< K5G D9F:CFA98 5G D5FH C: H<9 DF9GIF;=75@ 9J5@I5H=CB C:
H<9G9 D5H=9BHG CAD5F98 HC H<9 CH<9F H9GH98 A9H<C8G -#--3 =G ACF9
FC6IGH H<5B -.10 5B8 7&),. K<=7< GCA9H=A9G @958 HC F9GI@HG
H<5H 5F9 @9GG 7CB7CF85BH K=H< H<9 -! 5B5@MG=G IFH<9FACF9 -#--3 =G
ACF9 DF97=G9 =B 89@=B95H=B; H<9 57H=J9 6F5=B F9;=CBG H<5B 7&),. =
B5@@M :CF CB9 D5H=9BH H<9 GCIF79 @C75@=N5H=CB F9GI@HG C6H5=B98 6M -#--3
5F9 ACF9 7CB7CF85BH K=H< H<9 SB8=B;G C: H<9 -! 5B5@MG=G H<5B H<CG9
C: L-C'/-# 6975IG9 -#--3 577IF5H9@M 7<5F57H9F=N9G H<9 DFCD5;5
H=CB C: H<9 9D=@9DH=7 57H=J=HM K<=7< =G BCH H<9 75G9 :CF L-C'/-# )B
H<9 CH<9F <5B8 L-C'/-# @958G HC G@=;<H@M ACF9 7CB7CF85BH F9GI@HG
K=H< H<9 -! :CF HKC CH<9F D5H=9BHG CF H<9 @5GH D5H=9BH -#--3 5B8
L-C'/-# D9F:CFA 9EI5@@M K9@@ CF 5@@ D5H=9BHG K9 8C BCH C6G9FJ9
6=; 8=::9F9B79G =B H<9 @C75@=N98 6F5=B F9;=CBG K<9B 7CBG=89F=B; H<9 8=:
:9F9BH J5F=5BHG C: -#--3 "CK9J9F CB G=AI@5H98 85H5 H<9 D9F:CFA5B79
=ADFCJ9A9BH C: &-#--3 K=H< R   CJ9F -#--3 K=H< R   K5G
CB@M C6G9FJ98 =B H<9 75G9 C: 8=:S7I@H G79B5F=CG K=H< AI@H=D@9 D5H7<9G
GC H<9 G=A=@5F=HM C: H<9 F9GI@HG C: H<9G9 A9H<C8G CB H<9 7CBG=89F98 7@=B
=75@ 85H5 7CI@8 69 9LD@5=B98 6M H<9 :57H H<5H H<9 IB89F@M=B; GCIF79 7CB
S;IF5H=CBG 5F9 @9GG 7CAD@9L =B5@@M H<9 9LD@C=H5H=CB C: H9ADCF5@ GHFI7
HIF9 65G98 CB H<9 &BCFA <5G 5@GC 699B G<CKB HC =ADFCJ9 H<9 =BH9F
DF9H56=@=HM C: H<9 9GH=A5H98 H=A9 G=;B5@G =B H<9 75G9 C: 7@=B=75@ ! 85H5
5. Conclusion
#B 7CB7@IG=CB H<9 7CADIH9F G=AI@5H=CBG <5J9 G<CKB H<5H H<9 -#--3
5@;CF=H<A DFCDCG98 =B H<=G D5D9F =G 69HH9F =B G9D5F5H=B; AI@H=D@9 57H=J9
D5H7<9G H<5B H<9 CH<9F H9GH98 GCIF79 =A5;=B; A9H<C8G DFCJ=89G 5B =A
DFCJ98 9GH=A5H=CB C: H<9 GCIF79 H=A9 G=;B5@G 6M F9GCFH=B; HC H<9 &
BCFA F9;I@5F=N5H=CB H97<B=EI9 D9FA=HG HC 5IHCA5H=75@@M 89@=B95H9 H<9
57H=J9 6F5=B F9;=CBG 5B8 =G 7CADIH5H=CB5@@M 9:S7=9BH .<9 7@=B=75@ 85H5
9L5AD@9G <5J9 7CBSFA98 H<5H -#--3 M=9@8G F9GI@HG H<5H 5F9 7CB7CF85BH
K=H< H<9 9LD97H5H=CBG CB H<9 9D=@9DH=7 6F5=B F9;=CBG 65G98 CB 5B -!
5B5@MG=G .<9F9:CF9 -#--3 DFCJ9G HC 69 5 DFCA=G=B; A9H<C8 :CF H<9 F9

UNCORRECTED PROOF
-+2-9-;)3 -<964)/- ???  ??????
7CBGHFI7H=CB C: 9LH9B898 6F5=B GCIF79G =B D5FH=7I@5F :CF 5DD@=75H=CB =B
9D=@9DGM
IHIF9 KCF? K=@@ 7CBG=GH =B 9LH9B8=B; H<9 . 5DDFC57< HC CH<9F
GCIF79 =A5;=B; 5@;CF=H<AG 6M A5?=B; =H ACF9 FC6IGH HC 8=::9F9BH 7<5F
57H9F=GH=7G C: 9GH=A5H98 GCIF79 8=GHF=6IH=CBG IFH<9FACF9 K9 K=@@ 5D
D@M H<9 -#--3 5@;CF=H<A HC ACF9 9L5AD@9G C: 7@=B=75@ 85H5 =B CF89F HC
7CBSFA H<9 DF9@=A=B5FM F9GI@HG C: H<=G D5D9F BCH<9F F9G95F7< 8=F97H=CB
K=@@ 69 H<9 5DD@=75H=CB C: H<9 -#--3 5@;CF=H<A :CF GC@J=B; H<9 9@97HFC75F
8=C;F5D<M =BJ9FG9 DFC6@9A
Acknowledgements
" 97?9F K5G D5FH@M GIDDCFH98 6M CBG9=@ ,é;=CB5@ * 5B8
6M (,- F5B79 .<9 KCF? C: * CACB K5G D5FH@M :IB898 6M H<9
IFCD95B ,9G95F7< CIB7=@ IB89F H<9  H< :F5A9KCF? DFC;F5AA9
* !F5BH ;F99A9BH BC 
References
@=N589<  !C@8:5F6   -97CB8)F89F CB9 *FC;F5AA=B; ,IH;9FG /B=J9F
G=HM Q .97< ,9D
5=@@9H - 'CG<9F $ &95<M ,'  @97HFCA5;B9H=7 6F5=B A5DD=B; # -=;B5@
*FC79GG '5;  (CJ9A69F  Q
5@85GG5FF9 & 'CIF5C'=F5B85 $ *CBH=@ '  -HFI7HIF98 GD5FG=HM AC89@G :CF 6F5=B
897C8=B; :FCA :AF= 85H5 #B *FC7998=B;G C: *,(# CB:9F9B79 DD 
97?9F " @69F5 & CACB * !F=6CBJ5@ , '9F@9H # 5 5GH J5F=5H=CB65G98
A9H<C8G :CF H<9 5B5@MG=G C: 9LH9B898 6F5=B GCIF79G #B *FC7998=B;G C: /-#*) &=G
6CB *CFHI;5@
97?9F " @69F5 & CACB * !F=6CBJ5@ , 19B8@=B;  '9F@9H # 6 D9F:CF
A5B79 GHI8M C: J5F=CIG 6F5=B GCIF79 =A5;=B; 5DDFC57<9G #B *FC7998=B;G C: #--*
@CF9B79 #H5@M DD 
97?9F " @69F5 & CACB * !F=6CBJ5@ , 19B8@=B;  '9F@9H #  F5=B
GCIF79 =A5;=B; :FCA GD5FG9 HC H9BGCF AC89@G # -=;B5@ *FC79GG '5;  (CJ9A
69F  Q
97?9F " @69F5 & CACB * "55F8H ' =FCH ! 19B8@=B;  !5J5F9H ' éB5F
! '9F@9H #  ! 9LH9B898 GCIF79 @C75@=N5H=CB H9BGCF65G98 JG 7CBJ9BH=CB5@
A9H<C8G (9IFC#A5;9  I;IGH Q
=FCH ! @69F5 & 19B8@=B;  '9F@9H #  &C75@=G5H=CB C: 9LH9B898 6F5=B GCIF79G
:FCA !'! H<9 L-C'/-# 5DDFC57< (9IFC#A5;9  Q
C@GH58  05B 099B  (CK5? ,  -D579H=A9 9J9BH GD5FG9 D9B5@=N5H=CB :CF A5;
B9HC9@97HFC9B79D<5@C;F5D<M (9IFC#A5;9  Q
CM8 - *5F=?< ( <I  *9@95HC  7?GH9=B $  =GHF=6IH98 CDH=A=N5H=CB
5B8 GH5H=GH=75@ @95FB=B; J=5 5@H9FB5H=B; 8=F97H=CB A9H<C8 C: AI@H=D@=9FG CIB8 .F9B8G
'57< &95FB   Q
CM8 - 05B89B69F;<9 &  CBJ9L )DH=A=N5H=CB 5A6F=8;9 /B=J9FG=HM *F9GG
<5B; 1 (IAA9BA55  "G=9< $ &=B   -D5H=5@@M GD5FG9 GCIF79 7@IGH9F AC8
9@=B; 6M 7CADF9GG=J9 B9IFCA5;B9H=7 HCAC;F5D<M (9IFC#A5;9 '5M 
<CK8<IFM , &=B5 $' %C65M5G<=  !FCJ5   '! GCIF79 @C75@=N5H=CB C:
GD5H=5@@M 9LH9B898 ;9B9F5HCFG :CF 9D=@9DH=7 57H=J=HM 7CAD5F=B; 9BHFCD=7 5B8 <=9F5F7<=
75@ 5M9G=5B 5DDFC57<9G *@CG )B9   Q
CA69HH9G *& *9GEI9H $   DFCL=A5@ 897CADCG=H=CB A9H<C8 :CF GC@J=B; 7CB
J9L J5F=5H=CB5@ =BJ9FG9 DFC6@9AG #BJ9FG9 *FC6@ 979A69F 
5@9 ' -9F9BC '#  #ADFCJ98 @C75@=N5H=CB C: 7CFH=75@ 57H=J=HM 6M 7CA6=B=B;
! 5B8 '! K=H< ',# 7CFH=75@ GIF:579 F97CBGHFI7H=CB 5 @=B95F 5DDFC57< $ C;B
(9IFCG7=   Q
=B; &  ,97CBGHFI7H=B; 7CFH=75@ 7IFF9BH 89BG=HM 6M 9LD@CF=B; GD5FG9B9GG =B H<9
HF5BG:CFA 8CA5=B *<MG '98 =C@  Q
69FGC@9 $-  '5;B9HC9B79D<5@C;F5D<MA5;B9H=7 GCIF79 =A5;=B; =B H<9 5GG9GG
A9BH C: D5H=9BHG K=H< 9D=@9DGM D=@9DG=5  -Q
F=GHCB %$ "5FF=GCB & 5IB=N95I $ %=969@ - *<=@@=DG  .FI>=@@C5FF9HC ( "9B
GCB , @5B8=B ! '5HHCIH $  'I@H=D@9 GD5FG9 DF=CFG :CF H<9 '! =BJ9FG9
DFC6@9A (9IFC#A5;9   Q
!565M  '9F7=9F    8I5@ 5@;CF=H<A :CF H<9 GC@IH=CB C: BCB@=B95F J5F=5H=CB5@
DFC6@9AG J=5 SB=H9 9@9A9BHG 5DDFCL=A5H=CBG CADIH '5H< DD@  Q
!5J5F9H ' 58=9F $' '5FEI=G * '7!CB=;5@  5FHC@CA9=  ,9;=G $ <5I
J9@ *  @97HF=7 GCIF79 =A5;=B; =B :FCBH5@ @C69 9D=@9DGM $ @=B (9IFCD<MG
=C@  I;IGH  Q
!@CK=BG?= , '5FFC77C   -IF @5DDFCL=A5H=CB D5F é@éA9BHG SB=G 8CF8F9 IB
9H @5 FéGC@IH=CB D5F DéB5@=G5H=CB8I5@=Hé 8IB9 7@5GG9 89 DFC6@èA9G 89 8=F=7<@9H BCB
@=Bé5=F9G ,9J F IHCA #B:CFA H ,97< )DéF5H=CB9@@9  Q
!F5A:CFH   '5DD=B; H=A=B; 5B8 HF57?=B; 7CFH=75@ 57H=J5H=CBG K=H< '! 5B8 !
'9H<C8G 5B8 5DD@=75H=CB HC <IA5B J=G=CB *< H<9G=G .9@97CA *5F=G.97<
!F5A:CFH  %CK5@G?= ' "äAä@ä=B9B '  '=L98BCFA 9GH=A5H9G :CF H<9 '!
=BJ9FG9 DFC6@9A IG=B; 5779@9F5H98 ;F58=9BH A9H<C8G *<MG '98 =C@  Q
!F5A:CFH  *5D58CDCI@C . )@=J=  @9F7 '  )D9B'! CD9BGCIF79 GC:HK5F9
:CF EI5G= GH5H=7 6=C9@97HFCA5;B9H=7G =CA98 B; )B@=B9  
!F5A:CFH  .<=F=CB  05FCEI5IL !  #89BH=:M=B; DF98=7H=J9 F9;=CBG :FCA :',#
K=H< .0VDF=CF #B *FC7998=B;G C: *,(# CB:9F9B79
!F97< , 5GG5F . 'IG75H $ 5A=@@9F= %* 56F= -! 49FJ5?=G ' 25BH<CDCI@CG
* -5??5@=G 0 05BFIAGH9   ,9J=9K CB GC@J=B; H<9 =BJ9FG9 DFC6@9A =B !
GCIF79 5B5@MG=G $ (9IFC9B; ,9<56=@ (CJ9A69F 
%M6=7 $ @9F7 ' 66CI8 . 5I;9F5G ) %9F=J9B , *5D58CDCI@C .  7CA
ACB :CFA5@=GA :CF H<9 =BH9;F5@ :CFAI@5H=CBG C: H<9 :CFK5F8 ! DFC6@9A # .F5BG
'98 #A5;   Q
&=AD=H= . 05B 099B  15?5= ,.  CFH=75@ D5H7< 65G=G AC89@ :CF GD5H=5@@M 9L
H9B898 B9IF5@ 57H=J=HM # .F5BG =CA98 B;   Q
'5 - 3=B 1 4<5B; 3 <5?F56CFHM   B 9:S7=9BH 5@;CF=H<A :CF 7CADF9GG98
AF =A5;=B; IG=B; HCH5@ J5F=5H=CB 5B8 K5J9@9HG #B # *FC7998=B;G C: 0*, DD 
'9F@9H # !CHA5B $  ,9@=56=@=HM C: 8=DC@9 AC89@G C: 9D=@9DH=7 GD=?9G @=B (9IFC
D<MG=C@  $IB9  Q
'=?IB= ( (5;5A=B9 . #?985  .9F585 % .5?= 1 %=AIF5 $ %=?I7<= "
-<=65G5?= "  -=AI@H5B9CIG F97CF8=B; C: 9D=@9DH=:CFA 8=G7<5F;9G 6M '! 5B8
GI68IF5@ 9@97HFC89G =B H9ADCF5@ @C69 9D=@9DGM (9IFC#A5;9  Q
'CF95I $$  CB7H=CBG 7CBJ9L9G 8I5@9G 9H DC=BHG DFCL=A5IL 85BG IB 9GD579 <=@69F
H=9B , 758 -7= *5F=G -éF  '5H<  Q
)=G<= ' )HGI6C " %5A9M5A5 - 'CFCH5 ( '5GI85 " %=H5M5A5 ' .5B5?5 ,
 D=@9DH=7 GD=?9G A5;B9HC9B79D<5@C;F5D<M J9FGIG G=AI@H5B9CIG 9@97HFC7CFH=7C;
F5D<M D=@9DG=5   Q
)I  "äAä@ä=B9B ' !C@@5B8 *   8=GHF=6IH98 GD5H=CH9ADCF5@ !'! =BJ9FG9
GC@J9F (9IFC#A5;9 
*5G7I5@'5FEI= , '=7<9@ ' &9<A5BB   &CK F9GC@IH=CB 9@97HFCA5;B9H=7
HCAC;F5D<M 5 B9K A9H<C8 :CF @C75@=N=B; 9@97F=75@ 57H=J=HM =B H<9 6F5=B #BH $ *GM
7<CD<MG=C@  Q
-<=;9HC " 'CF=C?5 . "=G585 % (=G<=C - #G<=65G<= " %=F5  .C6=A5HGI - %5HC
'  95G=6=@=HM 5B8 @=A=H5H=CBG C: A5;B9HC9B79D<5@C;F5D<=7 89H97H=CB C: 9D=@9D
H=7 8=G7<5F;9G G=AI@H5B9CIG F97CF8=B; C: A5;B9H=7 S9@8G 5B8 9@97HFC7CFH=7C;F5D<M
(9IFC@ ,9G   Q
.5C $ "5K9G69FGC@9 - 69FGC@9 $  #BHF57F5B=5@ ! GI6GHF5H9G C: G75@D !
=BH9F=7H5@ GD=?9G D=@9DG=5  '5M  Q
.=6G<=F5B= , -5IB89FG (  -D5FG=HM 5B8 GACCH<B9GG J=5 H<9 :IG98 &--) $ ,
-H5H -C7   *5FH  Q
0=B79BH & -C=@@9 *  15H9FG<98G =B 8=;=H5@ GD579G 5B 9:S7=9BH 5@;CF=H<A 65G98
CB =AA9FG=CB G=AI@5H=CBG # .F5BG *5HH9FB B5@ '57< #BH9@@  $IB9 
Q
15;B9F ' I7<G ' 1=G7<A5BB " F9B7?<5<B ,  -ACCH< F97CBGHFI7H=CB
C: 7CFH=75@ GCIF79G :FCA ! 5B8 '! F97CF8=B;G (9IFC#A5;9   -
1=D:  (5;5F5>5B -   IB=S98 5M9G=5B :F5A9KCF? :CF '!! GCIF79 =A5;
=B; (9IFC#A5;9  Q
35C $ 9K5@8 $*  J5@I5H=CB C: 8=::9F9BH 7CFH=75@ GCIF79 @C75@=N5H=CB A9H<C8G
IG=B; G=AI@5H98 5B8 9LD9F=A9BH5@ ! 85H5 (9IFC#A5;9  DF=@  Q
4<I ' 4<5B; 1 =7?9BG & =B; &  ,97CBGHFI7H=B; GD5H=5@@M 9LH9B898 6F5=B
GCIF79G J=5 9B:CF7=B; AI@H=D@9 HF5BG:CFA GD5FG9B9GG (9IFC#A5;9  Q
4<I ' 4<5B; 1 =7?9BG & %=B; $ =B; &  -D5FG9 '! GCIF79 =A5;=B;
:CF F97CBGHFI7H=B; 8MB5A=7 9D=@9DH=7 GCIF79G C: =BH9F=7H5@ GD=?9G $ @=B (9IFCD<MG
=C@   Q

Article
Full-text available
The process of reconstructing underlying cortical and subcortical electrical activities from Electroencephalography (EEG) or Magnetoencephalography (MEG) recordings is called Electrophysiological Source Imaging (ESI). Given the complementarity between EEG and MEG in measuring radial and tangential cortical sources, combined EEG/MEG is considered beneficial in improving the reconstruction performance of ESI algorithms. Traditional algorithms mainly emphasize incorporating predesigned neurophysiological priors to solve the ESI problem. Deep learning frameworks aim to directly learn the mapping from scalp EEG/MEG measurements to the underlying brain source activities in a data-driven manner, demonstrating superior performance compared to traditional methods. However, most of the existing deep learning approaches for the ESI problem are performed on a single modality of EEG or MEG, meaning the complementarity of these two modalities has not been fully utilized. How to fuse the EEG and MEG in a more principled manner under the deep learning paradigm remains a challenging question. This study develops a Multi-Modal Deep Fusion (MMDF) framework using Attention Neural Networks (ANN) to fully leverage the complementary information between EEG and MEG for solving the ESI inverse problem, which is termed as MMDF-ANN . Specifically, our proposed brain source imaging approach consists of four phases, including feature extraction, weight generation, deep feature fusion, and source mapping. Our experimental results on both synthetic dataset and real dataset demonstrated that using a fusion of EEG and MEG can significantly improve the source localization accuracy compared to using a single-modality of EEG or MEG. Compared to the benchmark algorithms, MMDF-ANN demonstrated good stability when reconstructing sources with extended activation areas and situations of EEG/MEG measurements with a low signal-to-noise ratio.
Article
Full-text available
One of the most important needs in neuroimaging is brain dynamic source imaging with high spatial and temporal resolution. EEG source imaging estimates the underlying sources from EEG recordings, which provides enhanced spatial resolution with intrinsically high temporal resolution. To ensure identifiability in the underdetermined source reconstruction problem, constraints on EEG sources are essential. This paper introduces a novel method for estimating source activities based on spatio-temporal constraints and a dynamic source imaging algorithm. The method enhances time resolution by incorporating temporal evolution of neural activity into a regularization function. Additionally, two spatial regularization constraints based on L1{L}_{1} and L2{L}_{2} norms are applied in the transformed domain to address both focal and spread neural activities, achieved through spatial gradient and Laplacian transform. Performance evaluation, conducted quantitatively using synthetic datasets, discusses the influence of parameters such as source extent, number of sources, correlation level, and SNR level on temporal and spatial metrics. Results demonstrate that the proposed method provides superior spatial and temporal reconstructions compared to state-of-the-art inverse solutions including STRAPS, sLORETA, SBL, dSPM, and MxNE. This improvement is attributed to the simultaneous integration of transformed spatial and temporal constraints. When applied to a real auditory ERP dataset, our algorithm accurately reconstructs brain source time series and locations, effectively identifying the origins of auditory evoked potentials. In conclusion, our proposed method with spatio-temporal constraints outperforms the state-of-the-art algorithms in estimating source distribution and time courses.
Article
Full-text available
Electroencephalographic (EEG) source imaging (ESI) is a powerful method for studying brain functions and surgical resection of epileptic foci. However, accurately estimating the location and extent of brain sources remains challenging due to noise and background interference in EEG signals. To reconstruct extended brain sources, we propose a new ESI method called Variation Sparse Source Imaging based on Generalized Gaussian Distribution (VSSI-GGD). VSSI-GGD uses the generalized Gaussian prior as a sparse constraint on the spatial variation domain and embeds it into the Bayesian framework for source estimation. Using a variational technique, we approximate the intractable true posterior with a Gaussian density. Through convex analysis, the Bayesian inference problem is transformed entirely into a series of regularized L 2p -norm (0 < p < 1) optimization problems, which are efficiently solved with the ADMM algorithm. Imaging results of numerical simulations and human experimental dataset analysis reveal the superior performance of VSSI-GGD, which provides higher spatial resolution with clear boundaries compared to benchmark algorithms. VSSI-GGD can potentially serve as an effective and robust spatiotemporal EEG source imaging method. The source code of VSSI-GGD is available at https://github.com/Mashirops/VSSI-GGD.git.
Preprint
Full-text available
Magnetoencephalography (MEG) and electroencephalography (EEG) are widely employed techniques for the in-vivo measurement of neural activity with exceptional temporal resolution. Modeling the neural sources underlying these signals is of high interest for both neuroscience research and pathology. The method of Alternating Projections (AP) was recently shown to outperform the well-established recursively applied and projected multiple signal classification (RAP-MUSIC) algorithm. In this work, we further enhanced AP to allow for source extent estimation, a novel approach termed flexible extent AP (FLEX-AP). We found that FLEX-AP achieves significantly lower errors for spatially coherent sources compared to AP, RAP-MUSIC, and the corresponding extension, FLEX-RAP-MUSIC. We also found an advantage for discrete dipoles under forward modeling errors encountered in real-world scenarios. Together, our results indicate that the FLEX-AP method can unify dipole fitting and distributed source imaging into a single algorithm with promising accuracy.
Article
Objective: Reconstructing brain activities from electroencephalography (EEG) signals is crucial for studying brain functions and their abnormalities. However, since EEG signals are nonstationary and vulnerable to noise, brain activities reconstructed from single-trial EEG data are often unstable, and significant variability may occur across different EEG trials even for the same cognitive task. Methods: In an effort to leverage the shared information across the EEG data of multiple trials, this paper proposes a multi-trial EEG source imaging method based on Wasserstein regularization, termed WRA-MTSI. In WRA-MTSI, Wasserstein regularization is employed to perform multi-trial source distribution similarity learning, and the structured sparsity constraint is enforced to enable accurate estimation of the source extents, locations and time series. The resulting optimization problem is solved by a computationally efficient algorithm based on the alternating direction method of multipliers (ADMM). Results: Both numerical simulations and real EEG data analysis demonstrate that WRA-MTSI outperforms existing single-trial ESI methods (e.g., wMNE, LORETA, SISSY, and SBL) in mitigating the influence of artifacts in EEG data. Moreover, WRA-MTSI yields superior performance compared to other state-of-the-art multi-trial ESI methods (e.g., group lasso, the dirty model, and MTW) in estimating source extents. Conclusion and significance: WRA-MTSI may serve as an effective robust EEG source imaging method in the presence of multi-trial noisy EEG data. Code of WRA-MTSI is available at https://github.com/Zhen715code/WRA-MTSI.git.
Article
Full-text available
A number of application areas such as biomedical engineering require solving an underdetermined linear inverse problem. In such a case, it is necessary to make assumptions on the sources to restore identifiability. This problem is encountered in brain-source imaging when identifying the source signals from noisy electroencephalographic or magnetoencephalographic measurements. This inverse problem has been widely studied during recent decades, giving rise to an impressive number of methods using different priors. Nevertheless, a thorough study of the latter, including especially sparse and tensor-based approaches, is still missing. In this article, we propose 1) a taxonomy of the algorithms based on methodological considerations; 2) a discussion of the identifiability and convergence properties, advantages, drawbacks, and application domains of various techniques; and 3) an illustration of the performance of seven selected methods on identical data sets. Directions for future research in the area of biomedical imaging are eventually provided.
Article
Full-text available
Identifying the location and spatial extent of several highly correlated and simultaneously active brain sources from electroencephalographic (EEG) recordings and extracting the corresponding brain signals is a challenging problem. In a recent comparison of source imaging techniques, the VB-SCCD algorithm, which exploits the sparsity of the variational map of the sources, proved to be a promising approach. In this paper, we propose several ways to improve this method. In order to adjust the size of the estimated sources, we add a regularization term that imposes sparsity in the original source domain. Furthermore, we demonstrate the application of ADMM, which permits to efficiently solve the optimization problem. Finally, we also consider the exploitation of the temporal structure of the data by employing L1;2-norm regularization. The performance of the resulting algorithm, called L1;2-SVB-SCCD, is evaluated based on realistic simulations in comparison to VB-SCCD and several state-of-the-art techniques for extended source localization.
Article
Full-text available
The overall aim of this thesis is the development of novel electroencephalography (EEG) and magnetoencephalography (MEG) analysis methods to provide new insights to the functioning of the human brain. MEG and EEG are non-invasive techniques that measure outside of the head the electric potentials and the magnetic fields induced by the neuronal activity, respectively. The objective of these functional brain imaging modalities is to be able to localize in space and time the origin of the signal measured. To do so very challenging mathematical and computational problems needs to be tackled. The first part of this work proceeds from the biological origin the M/EEG signal to the resolution of the forward problem. Starting from Maxwell's equations in their quasi-static formulation and from a physical model of the head, the forward problem predicts the measurements that would be obtained for a given configuration of current generators. With realistic head models the solution is not known analytically and is obtained with numerical solvers. The first contribution of this thesis introduces a solution of this problem using a symmetric boundary element method (BEM) which has an excellent precision compared to alternative standard BEM implementations. Once a forward model is available the next challenge consists in recovering the current generators that have produced the measured signal. This problem is referred to as the inverse problem. Three types of approaches exist for solving this problem: parametric methods, scanning techniques, and image-based methods with distributed source models. This latter technique offers a rigorous formulation of the inverse problem without making strong modeling assumptions. However, it requires to solve a severely ill-posed problem. The resolution of such problems classically requires to impose constraints or priors on the solution. The second part of this thesis presents robust and tractable inverse solvers with a particular interest on efficient convex optimization methods using sparse priors. The third part of this thesis is the most applied contribution. It is a detailed exploration of the problem of retinotopic mapping with MEG measurements, from an experimental protocol design to data exploration, and resolution of the inverse problem using time frequency analysis. The next contribution of this thesis, aims at going one step further from simple source localization by providing an approach to investigate the dynamics of cortical activations. Starting from spatiotemporal source estimates the algorithm proposed provides a way to robustly track the "hot spots" over the cortical mesh in order to provide a clear view of the cortical processing over time. The last contribution of this work addresses the very challenging problem of single-trial data processing. We propose to make use of recent progress in graph-based methods in order to achieve parameter estimation on single-trial data and therefore reduce the estimation bias produced by standard multi-trial data averaging. Both the source code of our algorithms and the experimental data are freely available to reproduce the results presented. The retinotopy project was done in collaboration with the LENA team at the hôpital La Pitié-Salpêtrière (Paris).
Conference Paper
Full-text available
Decoding, i.e. predicting stimulus related quantities from functional brain images, is a powerful tool to demonstrate differences between brain activity across conditions. However, unlike standard brain mapping, it offers no guaranties on the localization of this information. Here, we consider decoding as a statistical estimation problem and show that injecting a spatial segmentation prior leads to unmatched performance in recovering predictive regions. Specifically, we use ℓ1-penalization to set voxels to zero and Total-Variation (TV) penalization to segment regions. Our contribution is two-fold. On the one hand, we show via extensive experiments that, amongst a large selection of decoding and brain-mapping strategies, TV+ℓ1 leads to best region recovery. On the other hand, we consider implementation issues related to this estimator. To tackle efficiently this joint prediction-segmentation problem we introduce a fast optimization algorithm based on a primal-dual approach. We also tackle automatic setting of hyper-parameters and fast computation of image operation on the irregular masks that arise in brain imaging.
Article
The numerical analysis of a given nonlinear Dirichlet problem is studied. The approximation is achieved by a finite element method and error estimates are given; the approximated problem is solved by an iterative algorithm combining S. O. R. , penalty and duality. An extension to other nonlinear problems is given, along with numerical results.
Article
The localization of brain sources based on EEG measurements is a topic that has attracted a lot of attention in the last decades and many different source localization algorithms have been proposed. However, their performance is limited in the case of several simultaneously active brain regions and low signal-to-noise ratios. To overcome these problems, tensor-based preprocessing can be applied, which consists in constructing a space-time-frequency (STF) or space-time-wave-vector (STWV) tensor and decomposing it using the Canonical Polyadic (CP) decomposition. In this paper, we present a new algorithm for the accurate localization of extended sources based on the results of the tensor decomposition. Furthermore, we conduct a detailed study of the tensor-based preprocessing methods, including an analysis of their theoretical foundation, their computational complexity, and their performance for realistic simulated data in comparison to conventional source localization algorithms such as sLORETA, cortical LORETA (cLORETA), and 4-ExSo-MUSIC. Our objective consists, on the one hand, in demonstrating the gain in performance that can be achieved by tensor-based preprocessing, and, on the other hand, in pointing out the limits and drawbacks of this method. Finally, we validate the STF and STWV techniques on real measurements to demonstrate their usefulness for practical applications.
Conference Paper
Structured sparsity methods have been recently proposed that allow to incorporate additional spatial and temporal information for estimating models for decoding mental states from fMRI data. These methods carry the promise of being more interpretable than simpler Lasso or Elastic Net methods. However, despite sparsity has often been advocated as leading to more interpretable models, we show that by itself sparsity and also structured sparsity could lead to unstable models. We present an extension of the Total Variation method and assess several other structured sparsity models on accuracy, sparsity and stability. Our results indicate that structured sparsity via the Sparse Total Variation can mitigate some of the instability inherent in simpler sparse methods, but more research is required to build methods that can reliably infer relevant activation patterns from fMRI data.
Article
Accurate estimation of location and extent of neuronal sources from EEG/MEG remains challenging. In the present study, a new source imaging method, i.e. variation and wavelet based sparse source imaging (VW-SSI), is proposed to better estimate cortical source locations and extents. VW-SSI utilizes the L1-norm regularization method with the enforcement of transform sparseness in both variation and wavelet domains. The performance of the proposed method is assessed by both simulated and experimental MEG data, obtained from a language task and a motor task. Compared to L2-norm regularizations, VW-SSI demonstrates significantly improved capability in reconstructing multiple extended cortical sources with less spatial blurredness and less localization error. With the use of transform sparseness, VW-SSI overcomes the over-focused problem in classic SSI methods. With the use of two transformations, VW-SSI further indicates significantly better performance in estimating MEG source locations and extents than other SSI methods with single transformations. The present experimental results indicate that VW-SSI can successfully estimate neural sources (and their spatial coverage) located in close areas while responsible for different functions, i.e. temporal cortical sources for auditory and language processing, and sources on the pre-bank and post-bank of the central sulcus. Meantime, all other methods investigated in the present study fail to recover these phenomena. Precise estimation of cortical source locations and extents from EEG/MEG is of significance for applications in neuroscience and neurology.