File size: 55,919 Bytes
6fa4bc9
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
{
    "paper_id": "D13-1003",
    "header": {
        "generated_with": "S2ORC 1.0.0",
        "date_generated": "2023-01-19T16:42:28.026561Z"
    },
    "title": "Combining Generative and Discriminative Model Scores for Distant Supervision",
    "authors": [
        {
            "first": "Benjamin",
            "middle": [],
            "last": "Roth",
            "suffix": "",
            "affiliation": {
                "laboratory": "",
                "institution": "Saarland University Spoken Language Systems Saarbr\u00fccken",
                "location": {
                    "country": "Germany"
                }
            },
            "email": ""
        },
        {
            "first": "Dietrich",
            "middle": [],
            "last": "Klakow",
            "suffix": "",
            "affiliation": {
                "laboratory": "",
                "institution": "Saarland University Spoken Language Systems Saarbr\u00fccken",
                "location": {
                    "country": "Germany"
                }
            },
            "email": ""
        }
    ],
    "year": "",
    "venue": null,
    "identifiers": {},
    "abstract": "Distant supervision is a scheme to generate noisy training data for relation extraction by aligning entities of a knowledge base with text. In this work we combine the output of a discriminative at-least-one learner with that of a generative hierarchical topic model to reduce the noise in distant supervision data. The combination significantly increases the ranking quality of extracted facts and achieves state-of-the-art extraction performance in an end-to-end setting. A simple linear interpolation of the model scores performs better than a parameter-free scheme based on nondominated sorting.",
    "pdf_parse": {
        "paper_id": "D13-1003",
        "_pdf_hash": "",
        "abstract": [
            {
                "text": "Distant supervision is a scheme to generate noisy training data for relation extraction by aligning entities of a knowledge base with text. In this work we combine the output of a discriminative at-least-one learner with that of a generative hierarchical topic model to reduce the noise in distant supervision data. The combination significantly increases the ranking quality of extracted facts and achieves state-of-the-art extraction performance in an end-to-end setting. A simple linear interpolation of the model scores performs better than a parameter-free scheme based on nondominated sorting.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Abstract",
                "sec_num": null
            }
        ],
        "body_text": [
            {
                "text": "Relation extraction is the task of finding relational facts in unstructured text and putting them into a structured (tabularized) knowledge base. Training machine learning algorithms for relation extraction requires training data. If the set of relations is prespecified, the training data needs to be labeled with those relations.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "Manual annotation of training data is laborious and costly, however, the knowledge base may already partially be filled with instances from the relations. This is utilized by a scheme known as distant supervision (DS) (Mintz et al., 2009) : text is automatically labeled by aligning (matching) pairs of entities that are contained in a knowledge base with their textual occurrences. Whenever such a match is encountered, the surrounding context (sentence) is assumed to express the relation.",
                "cite_spans": [
                    {
                        "start": 218,
                        "end": 238,
                        "text": "(Mintz et al., 2009)",
                        "ref_id": "BIBREF11"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "This assumption, however, can fail. Consider the example given in (Takamatsu et al., 2012) : If the tuple",
                "cite_spans": [
                    {
                        "start": 66,
                        "end": 90,
                        "text": "(Takamatsu et al., 2012)",
                        "ref_id": "BIBREF16"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "place_of_birth(Michael Jackson, Gary)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "is contained in the knowledge base, one matching context could be: Michael Jackson was born in Gary ...",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "Michael Jackson moved from Gary ... Clearly, only the first context indeed expresses the relation and should be labeled accordingly.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "And another possible context:",
                "sec_num": null
            },
            {
                "text": "Three basic approaches have been proposed to deal with noisy distant supervision instances: The discriminative at-least-one approach , that requires that at least one of the matches for a relation-entity tuple indeed expresses the relation; The generative approach (Alfonseca et al., 2012) that separates relation-specific distributions from noise distributions by using hierarchical topic models; And the pattern correlation approach (Takamatsu et al., 2012) that assumes that contexts which match argument pairs have a high overlap in argument pairs with other patterns expressing the relation.",
                "cite_spans": [
                    {
                        "start": 265,
                        "end": 289,
                        "text": "(Alfonseca et al., 2012)",
                        "ref_id": "BIBREF5"
                    },
                    {
                        "start": 435,
                        "end": 459,
                        "text": "(Takamatsu et al., 2012)",
                        "ref_id": "BIBREF16"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "And another possible context:",
                "sec_num": null
            },
            {
                "text": "In this work we combine 1) a discriminative atleast-one learner, that requires high scores for both a dedicated noise label and the matched relation, and 2) a generative topic model that uses a feature-based representation to separate relation-specific patterns from background or pair-specific noise. We score surface patterns and show that combining the two approaches results in a better ranking quality of relational facts. In an end-to-end evaluation we set a threshold on the pattern scores and apply the pat- terns in a TAC KBP-style evaluation. Although the surface patterns are very simple (only strings of tokens), they achieve state-of-the-art extraction results.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "And another possible context:",
                "sec_num": null
            },
            {
                "text": "The original form of distant supervision (Mintz et al., 2009) assumes all sentences containing an entity pair to be potential patterns for the relation holding between the entities. A variety of models relax this assumption and only presume that at least one of the entity pair occurrences is a textual manifestation of the relation. The first proposed model with an atleast-one learner is that of and . It consists of a factor graph that includes binary variables for contexts, and groups contexts together for each entity pair. MultiR (Hoffmann et al., 2011) can be viewed as a multi-label extension of . A further extension is MIMLRE (Surdeanu et al., 2012) , a jointly trained two-stage classification model.",
                "cite_spans": [
                    {
                        "start": 41,
                        "end": 61,
                        "text": "(Mintz et al., 2009)",
                        "ref_id": "BIBREF11"
                    },
                    {
                        "start": 637,
                        "end": 660,
                        "text": "(Surdeanu et al., 2012)",
                        "ref_id": "BIBREF15"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "At-Least-One Models",
                "sec_num": "2.1"
            },
            {
                "text": "The hierarchical topic model (HierTopics) by Alfonseca et al. (2012) models the distant supervision data by a generative model. For each corpus match of an entity pair in the knowledge base, the corresponding surface pattern is assumed to be typical for either the entity pair, the relation, or neither. This principle is then used to infer distributions over patterns of one of the following types:",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Hierarchical Topic Model",
                "sec_num": "2.2"
            },
            {
                "text": "1. For every entity pair, a pair-specific distribution.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Hierarchical Topic Model",
                "sec_num": "2.2"
            },
            {
                "text": "2. For every relation, a relation-specific distribution.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Hierarchical Topic Model",
                "sec_num": "2.2"
            },
            {
                "text": "The generative process assumes that for each argument pair in the knowledge base, all patterns are generated by first choosing a hidden variable z which can take on three values, B for background, R for relation and P for pair. Corresponding vocabulary distributions (\u03c6 bg , \u03c6 rel , \u03c6 pair ) for generating the context patterns are chosen according to the value of z. The Dirichlet-smoothed vocabulary distributions are shared on the respective levels. Figure 1 shows the plate diagram of the HierTopics model.",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 453,
                        "end": 461,
                        "text": "Figure 1",
                        "ref_id": "FIGREF0"
                    }
                ],
                "eq_spans": [],
                "section": "A general background distribution.",
                "sec_num": "3."
            },
            {
                "text": "We use a feature-based extension (Roth and Klakow, 2013) of Alfonseca et al. (2012) to include bigrams for a more fine-grained representation of the patterns. For including features in the model, the model is extended with a second layer of hidden variables. A variable x represents a choice of B, R or P for every pattern, i.e. there is one variable x for every pattern. Each feature is generated conditioned on a second variable z \u2208 {B, R, P }, i.e. there are as many variables z for a pattern as there are features for it. First, the hidden variable x is generated, then all z variables are generated for the corresponding features (see Figure 1) . The values B, R or P of z depend on the corresponding x by a transition distribution:",
                "cite_spans": [
                    {
                        "start": 33,
                        "end": 56,
                        "text": "(Roth and Klakow, 2013)",
                        "ref_id": "BIBREF13"
                    },
                    {
                        "start": 60,
                        "end": 83,
                        "text": "Alfonseca et al. (2012)",
                        "ref_id": "BIBREF5"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 640,
                        "end": 649,
                        "text": "Figure 1)",
                        "ref_id": "FIGREF0"
                    }
                ],
                "eq_spans": [],
                "section": "Generative Model",
                "sec_num": "3.1"
            },
            {
                "text": "P (Z i = z|X j(i) = x) = p same , if z = x 1\u2212psame 2 , otherwise",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Generative Model",
                "sec_num": "3.1"
            },
            {
                "text": "where features at indices i are mapped to the corresponding pattern indices by a function j(i); p same is set to .99 to enforce the correspondence between pattern and feature topics. 1",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Generative Model",
                "sec_num": "3.1"
            },
            {
                "text": "As a second feature-based model, we employ a perceptron model that enforces constraints on the labels for patterns (Roth and Klakow, 2013) . The model consists of log-linear factors for the set of relations Algorithm 1 At-Least-One Perceptron Training",
                "cite_spans": [
                    {
                        "start": 115,
                        "end": 138,
                        "text": "(Roth and Klakow, 2013)",
                        "ref_id": "BIBREF13"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": "\u03b8 \u2190 0 for r \u2208 R do for pair \u2208 kb pairs(r) do for s \u2208 sentences(pair) do for r \u2208 R \\ r do if P (r|s, \u03b8) \u2264 P (r |s, \u03b8) then \u03b8 \u2190 \u03b8 + \u03c6(s, r) \u2212 \u03c6(s, r ) if P (N IL|s, \u03b8) \u2264 P (r |s, \u03b8) then \u03b8 \u2190 \u03b8 + \u03c6(s, N IL) \u2212 \u03c6(s, r ) if \u2200 s\u2208sentences(pair) : P (r|s, \u03b8) \u2264 P (N IL|s, \u03b8) then s * = arg maxs P (r|s,\u03b8) P (N IL|s,\u03b8) \u03b8 \u2190 \u03b8 + \u03c6(s * , r) \u2212 \u03c6(s * , N IL)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": "R as well as a factor for the NIL label (no relation).",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": "Probabilities for a relation r given a sentence pattern s are calculated by normalizing over log-linear factors defined as f",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": "r (s) = exp ( i \u03c6 i (s, r)\u03b8 i )",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": ", with \u03c6(s, r) the feature vector for sentence s and label assignment r, and \u03b8 r the feature weight vector. The learner is directed by the following semantics: First, for a sentence s that has a distant supervision match for relation r, relation r should have a higher probability than any other relation r \u2208 R \\ r. As extractions are expected to be noisy, high probabilities for N IL are enforced by a second constraint: N IL must have a higher probability than any relation r \u2208 R \\ r. Third, at least one DS sentence for an argument pair is expected to express the corresponding relation r. For sentences s for an entity pair belonging to relation r, this can be written as the following constraints: \u2200 s,r : P (r|s) > P (r |s) \u2227 P (N IL|s) > P (r |s) \u2203 s : P (r|s) > P (N IL|s) The violation of any of the above constraints triggers a perceptron update. The basic algorithm is sketched in Algorithm 1. 2",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Discriminative Model",
                "sec_num": "3.2"
            },
            {
                "text": "The per-pattern probabilities P (r|pat) are calculated as in Alfonseca et al. (2012) and aggregated over all pattern occurrences: For the topic model, the number of times the relation-specific topic has been sampled for a pattern is divided by n(pat), the number of times the same pattern has been observed. Analogously for the perceptron, the number of times a pattern co-occurs with entity pairs for r is multiplied by the perceptron score and divided by n(pat). The topic model and perceptron approaches are based on plausible yet fundamentally different principles of modeling noise without direct supervision. It is therefore an interesting question how complementary the models are and how much can be gained from a combination. As the two models do not use direct supervision, we also avoid tuning parameters for their combination.",
                "cite_spans": [
                    {
                        "start": 61,
                        "end": 84,
                        "text": "Alfonseca et al. (2012)",
                        "ref_id": "BIBREF5"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Model Combination",
                "sec_num": "3.3"
            },
            {
                "text": "We use two schemes to obtain a combined ranking from the two model scores: The first is a ranking based on non-dominated sorting by successively computing the Pareto-frontier of the 2-dimensional score vectors (Borzsony et al., 2001; Godfrey et al., 2007) . The underlying principle is that all data points (patterns in our case) that are not dominated by another point 3 build the frontier and are ranked highest (see Figure 2) , with ties broken by linear combination. Sorting by computing the Paretofrontier has been applied to training machine translation systems (Duh et al., 2012) to combine the translation quality metrics BLEU, RIBES and NTER, each of which is based on different principles. In the context of machine translation it has been found to outperform a linear interpolation of the metrics and to be more stable to non-smooth metrics and noncomparable scalings. We compare non-dominated sorting with a simple linear interpolation with uniform weights.",
                "cite_spans": [
                    {
                        "start": 210,
                        "end": 233,
                        "text": "(Borzsony et al., 2001;",
                        "ref_id": "BIBREF6"
                    },
                    {
                        "start": 234,
                        "end": 255,
                        "text": "Godfrey et al., 2007)",
                        "ref_id": "BIBREF8"
                    },
                    {
                        "start": 568,
                        "end": 586,
                        "text": "(Duh et al., 2012)",
                        "ref_id": "BIBREF7"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 419,
                        "end": 428,
                        "text": "Figure 2)",
                        "ref_id": "FIGREF2"
                    }
                ],
                "eq_spans": [],
                "section": "Model Combination",
                "sec_num": "3.3"
            },
            {
                "text": "Evaluation is done on the ranking quality according to TAC KBP gold annotations (Ji et al., 2010) of extracted facts from all TAC KBP queries from 2009-2011 and the TAC KBP 2009-2011 corpora. First, candidate sentences are retrieved in which the query entity and a second entity with the appropriate type are contained. Candidate sentences are then used to provide answer candidates if one of the extracted patterns matches. The answer candidates are ranked according to the score of the matching pattern.",
                "cite_spans": [
                    {
                        "start": 80,
                        "end": 97,
                        "text": "(Ji et al., 2010)",
                        "ref_id": "BIBREF10"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Evaluation 4.1 Ranking-Based Evaluation",
                "sec_num": "4"
            },
            {
                "text": "The basis for pattern extraction is the noisy DS training data of a top-3 ranked system in TAC KBP 2012 (Roth et al., 2012) . The retrieval component of this system is used to obtain sentence and answer candidates (ranked according to their respective pattern scores). Evaluation results are reported as averages over per-relation results of the standard ranking metrics mean average precision (map), geometric map (gmap), precision at 5 and at 10 (p@5, p@10).",
                "cite_spans": [
                    {
                        "start": 104,
                        "end": 123,
                        "text": "(Roth et al., 2012)",
                        "ref_id": "BIBREF14"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Evaluation 4.1 Ranking-Based Evaluation",
                "sec_num": "4"
            },
            {
                "text": "The maximum-likelihood estimator (MLE) baseline scores patterns by the relative frequency they occur with a certain relation. The hierarchical topic (hier orig) as described in Alfonseca et al. (2012) increases the scores under most metrics, however the increase is only significant for p@5 and p@10. The feature-based extension of the topic model (hier feat) has significantly better ranking quality. Slightly better scores are obtained by the at-leastone perceptron learner. It is interesting to see that the model combinations both by non-dominated sorting perc+hier (pareto) as well as uniform interpolation perc+hier (itpl) give a further increase in ranking quality. The simpler interpolation scheme generally works best. Figure 3 shows the Precision/Recall curves of the basic models and the linear interpolation. On the P/R curve, the linear interpolation is equal or better than the single methods on all recall levels.",
                "cite_spans": [
                    {
                        "start": 177,
                        "end": 200,
                        "text": "Alfonseca et al. (2012)",
                        "ref_id": "BIBREF5"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 728,
                        "end": 736,
                        "text": "Figure 3",
                        "ref_id": "FIGREF3"
                    }
                ],
                "eq_spans": [],
                "section": "Evaluation 4.1 Ranking-Based Evaluation",
                "sec_num": "4"
            },
            {
                "text": "We evaluate the extraction quality of the induced perc+hier (itpl) patterns in an end-to-end setting. We use the evaluation setting of (Surdeanu et al., 2012) and the results obtained with their pipeline for MIMLRE and their re-implementation of MultiR as a point of reference.",
                "cite_spans": [
                    {
                        "start": 135,
                        "end": 158,
                        "text": "(Surdeanu et al., 2012)",
                        "ref_id": "BIBREF15"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "End-To-End Evaluation",
                "sec_num": "4.2"
            },
            {
                "text": "In Surdeanu et al. (2012) evaluation is done using a subset of queries from the TAC KBP 2010 and 2011 evaluation. The source corpus is the TAC KBP source corpus and a 2010 Wikipedia dump. Only those answers are considered in scoring that are contained in a list of possible answers from their candidates (reducing the number of gold answers from 1601 to 576 and thereby considerably increasing the value of reported recall).",
                "cite_spans": [
                    {
                        "start": 3,
                        "end": 25,
                        "text": "Surdeanu et al. (2012)",
                        "ref_id": "BIBREF15"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "End-To-End Evaluation",
                "sec_num": "4.2"
            },
            {
                "text": "For evaluating our patterns, we take the same queries for testing as Surdeanu et al. (2012) . As the document collection, we use the TAC KBP source collection and a Wikipedia dump from 07/2009 that was available to us. From this document collection, we use our retrieval pipeline of Roth et al. (2012) and take those sentences that contain query entities and slot filler candidates according to NEtags. We filter out all candidates that are not contained in the list of candidates considered in (Surdeanu et al., 2012) , and use the same reduced set of 576 gold answers as the key. We tune a single threshold parameter t = .3 on held-out development data and take all patterns with higher scores. Table 2 shows that results obtained with the induced patterns compare well with state-of-the-art relation extraction systems. Table 2 : TAC Scores on (Surdeanu et al., 2012) queries. Figure 4 shows top-ranked patterns for per:title and org:top members employees, the two relations with most answers in the gold annotations. For maximum likelihood estimation the score is 1.0 if the patterns occurs only with the relation in question -this includes all cases where the pattern is only found once in the corpus. While this could be circumvented by frequency thresholding, we leave the long tail of the data as it is and let the algorithm deal with both frequent and infrequent patterns.",
                "cite_spans": [
                    {
                        "start": 69,
                        "end": 91,
                        "text": "Surdeanu et al. (2012)",
                        "ref_id": "BIBREF15"
                    },
                    {
                        "start": 283,
                        "end": 301,
                        "text": "Roth et al. (2012)",
                        "ref_id": "BIBREF14"
                    },
                    {
                        "start": 495,
                        "end": 518,
                        "text": "(Surdeanu et al., 2012)",
                        "ref_id": "BIBREF15"
                    },
                    {
                        "start": 847,
                        "end": 870,
                        "text": "(Surdeanu et al., 2012)",
                        "ref_id": "BIBREF15"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 697,
                        "end": 704,
                        "text": "Table 2",
                        "ref_id": null
                    },
                    {
                        "start": 823,
                        "end": 830,
                        "text": "Table 2",
                        "ref_id": null
                    },
                    {
                        "start": 880,
                        "end": 888,
                        "text": "Figure 4",
                        "ref_id": "FIGREF4"
                    }
                ],
                "eq_spans": [],
                "section": "End-To-End Evaluation",
                "sec_num": "4.2"
            },
            {
                "text": "One can see that while the maximum likelihood patterns contain some reasonable relational contexts, they are less prototypical and more prone to distant supervision errors. The patterns scored high by the proposed combination generalize better, variation at the top is achieved by re-combining elements that carry relational meaning (\"is an\", \"vice president\", \"president director\") or are closely correlated to the particular relation. a feature-based extension of a hierarchical topic model, and an at-least-one perceptron. Interpolation increases the quality of extractions and achieves state-of-the-art extraction performance. A combination scheme based on non-dominated sorting, that was inspired by work on combining machine translation metrics, was not as good as a simple linear combination of scores. We think that the good results motivate research into more integrated combinations of noise reduction approaches.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Illustration: Top-Ranked Patterns",
                "sec_num": "4.3"
            },
            {
                "text": "The hyper-parameters used for the feature-based topic model are \u03b1 = (1, 1, 1) and \u03b2 = (.1, .001, .001).",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "",
                "sec_num": null
            },
            {
                "text": "A data point h1 dominates a data point h2 if h1 \u2265 h2 in all metrics and h1 > h2 in at least one metric.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "",
                "sec_num": null
            }
        ],
        "back_matter": [
            {
                "text": "Benjamin Roth is a recipient of the Google Europe Fellowship in Natural Language Processing, and this research is supported in part by this Google Fellowship.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Acknowledgment",
                "sec_num": null
            }
        ],
        "bib_entries": {
            "BIBREF4": {
                "ref_id": "b4",
                "title": "s responsibility to pin down just how the government decided to front $ 30 billion in taxpayer dollars for the Bear Stearns deal",
                "authors": [],
                "year": null,
                "venue": "",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "*[ARG1] 's responsibility to pin down just how the government decided to front $ 30 billion in taxpayer dollars for the Bear Stearns deal , \" Chairman [ARG2] org:top members employees, perc+hier (itpl) [ARG2] , Vice President of the [ARG1] [ARG1] Vice president [ARG2] [ARG1] president director [ARG2] [ARG1] vice president director [ARG2] [ARG1] Board member [ARG2]",
                "links": null
            },
            "BIBREF5": {
                "ref_id": "b5",
                "title": "Pattern learning for relation extraction with a hierarchical topic model",
                "authors": [
                    {
                        "first": "Enrique",
                        "middle": [],
                        "last": "Alfonseca",
                        "suffix": ""
                    },
                    {
                        "first": "Katja",
                        "middle": [],
                        "last": "Filippova",
                        "suffix": ""
                    },
                    {
                        "first": "Jean-Yves",
                        "middle": [],
                        "last": "Delort",
                        "suffix": ""
                    },
                    {
                        "first": "Guillermo",
                        "middle": [],
                        "last": "Garrido",
                        "suffix": ""
                    }
                ],
                "year": 2012,
                "venue": "Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics: Short Papers",
                "volume": "2",
                "issue": "",
                "pages": "54--59",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Enrique Alfonseca, Katja Filippova, Jean-Yves Delort, and Guillermo Garrido. 2012. Pattern learning for relation extraction with a hierarchical topic model. In Proceedings of the 50th Annual Meeting of the Asso- ciation for Computational Linguistics: Short Papers- Volume 2, pages 54-59. Association for Computa- tional Linguistics.",
                "links": null
            },
            "BIBREF6": {
                "ref_id": "b6",
                "title": "The skyline operator",
                "authors": [
                    {
                        "first": "S",
                        "middle": [],
                        "last": "Borzsony",
                        "suffix": ""
                    },
                    {
                        "first": "Donald",
                        "middle": [],
                        "last": "Kossmann",
                        "suffix": ""
                    },
                    {
                        "first": "Konrad",
                        "middle": [],
                        "last": "Stocker",
                        "suffix": ""
                    }
                ],
                "year": 2001,
                "venue": "Proceedings. 17th International Conference on",
                "volume": "",
                "issue": "",
                "pages": "421--430",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "S Borzsony, Donald Kossmann, and Konrad Stocker. 2001. The skyline operator. In Data Engineering, 2001. Proceedings. 17th International Conference on, pages 421-430. IEEE.",
                "links": null
            },
            "BIBREF7": {
                "ref_id": "b7",
                "title": "Learning to translate with multiple objectives",
                "authors": [
                    {
                        "first": "Kevin",
                        "middle": [],
                        "last": "Duh",
                        "suffix": ""
                    },
                    {
                        "first": "Katsuhito",
                        "middle": [],
                        "last": "Sudoh",
                        "suffix": ""
                    },
                    {
                        "first": "Xianchao",
                        "middle": [],
                        "last": "Wu",
                        "suffix": ""
                    },
                    {
                        "first": "Hajime",
                        "middle": [],
                        "last": "Tsukada",
                        "suffix": ""
                    },
                    {
                        "first": "Masaaki",
                        "middle": [],
                        "last": "Nagata",
                        "suffix": ""
                    }
                ],
                "year": 2012,
                "venue": "Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics: Long Papers",
                "volume": "1",
                "issue": "",
                "pages": "1--10",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Kevin Duh, Katsuhito Sudoh, Xianchao Wu, Hajime Tsukada, and Masaaki Nagata. 2012. Learning to translate with multiple objectives. In Proceedings of the 50th Annual Meeting of the Association for Com- putational Linguistics: Long Papers-Volume 1, pages 1-10. Association for Computational Linguistics.",
                "links": null
            },
            "BIBREF8": {
                "ref_id": "b8",
                "title": "Algorithms and analyses for maximal vector computation",
                "authors": [
                    {
                        "first": "Parke",
                        "middle": [],
                        "last": "Godfrey",
                        "suffix": ""
                    },
                    {
                        "first": "Ryan",
                        "middle": [],
                        "last": "Shipley",
                        "suffix": ""
                    },
                    {
                        "first": "Jarek",
                        "middle": [],
                        "last": "Gryz",
                        "suffix": ""
                    }
                ],
                "year": 2007,
                "venue": "The VLDB JournalThe International Journal on Very Large Data Bases",
                "volume": "16",
                "issue": "",
                "pages": "5--28",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Parke Godfrey, Ryan Shipley, and Jarek Gryz. 2007. Al- gorithms and analyses for maximal vector computa- tion. The VLDB JournalThe International Journal on Very Large Data Bases, 16(1):5-28.",
                "links": null
            },
            "BIBREF9": {
                "ref_id": "b9",
                "title": "Knowledgebased weak supervision for information extraction of overlapping relations",
                "authors": [
                    {
                        "first": "Raphael",
                        "middle": [],
                        "last": "Hoffmann",
                        "suffix": ""
                    },
                    {
                        "first": "Congle",
                        "middle": [],
                        "last": "Zhang",
                        "suffix": ""
                    },
                    {
                        "first": "Xiao",
                        "middle": [],
                        "last": "Ling",
                        "suffix": ""
                    },
                    {
                        "first": "Luke",
                        "middle": [],
                        "last": "Zettlemoyer",
                        "suffix": ""
                    },
                    {
                        "first": "Daniel",
                        "middle": [
                            "S"
                        ],
                        "last": "Weld",
                        "suffix": ""
                    }
                ],
                "year": 2011,
                "venue": "Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies",
                "volume": "",
                "issue": "",
                "pages": "541--550",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Raphael Hoffmann, Congle Zhang, Xiao Ling, Luke Zettlemoyer, and Daniel S Weld. 2011. Knowledge- based weak supervision for information extraction of overlapping relations. In Proceedings of the 49th An- nual Meeting of the Association for Computational Linguistics: Human Language Technologies, vol- ume 1, pages 541-550.",
                "links": null
            },
            "BIBREF10": {
                "ref_id": "b10",
                "title": "Overview of the tac 2010 knowledge base population track",
                "authors": [
                    {
                        "first": "Heng",
                        "middle": [],
                        "last": "Ji",
                        "suffix": ""
                    },
                    {
                        "first": "Ralph",
                        "middle": [],
                        "last": "Grishman",
                        "suffix": ""
                    },
                    {
                        "first": "Hoa",
                        "middle": [
                            "Trang"
                        ],
                        "last": "Dang",
                        "suffix": ""
                    },
                    {
                        "first": "Kira",
                        "middle": [],
                        "last": "Griffitt",
                        "suffix": ""
                    },
                    {
                        "first": "Joe",
                        "middle": [
                            "Ellis"
                        ],
                        "last": "",
                        "suffix": ""
                    }
                ],
                "year": 2010,
                "venue": "Third Text Analysis Conference",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Heng Ji, Ralph Grishman, Hoa Trang Dang, Kira Grif- fitt, and Joe Ellis. 2010. Overview of the tac 2010 knowledge base population track. In Third Text Anal- ysis Conference (TAC 2010).",
                "links": null
            },
            "BIBREF11": {
                "ref_id": "b11",
                "title": "Distant supervision for relation extraction without labeled data",
                "authors": [
                    {
                        "first": "Mike",
                        "middle": [],
                        "last": "Mintz",
                        "suffix": ""
                    },
                    {
                        "first": "Steven",
                        "middle": [],
                        "last": "Bills",
                        "suffix": ""
                    },
                    {
                        "first": "Rion",
                        "middle": [],
                        "last": "Snow",
                        "suffix": ""
                    },
                    {
                        "first": "Dan",
                        "middle": [],
                        "last": "Jurafsky",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "Proceedings of the Joint Conference of the 47th Annual Meeting of the ACL and the 4th International Joint Conference on Natural Language Processing of the AFNLP",
                "volume": "2",
                "issue": "",
                "pages": "1003--1011",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Mike Mintz, Steven Bills, Rion Snow, and Dan Jurafsky. 2009. Distant supervision for relation extraction with- out labeled data. In Proceedings of the Joint Confer- ence of the 47th Annual Meeting of the ACL and the 4th International Joint Conference on Natural Lan- guage Processing of the AFNLP: Volume 2-Volume 2, pages 1003-1011. Association for Computational Lin- guistics.",
                "links": null
            },
            "BIBREF12": {
                "ref_id": "b12",
                "title": "Modeling relations and their mentions without labeled text",
                "authors": [
                    {
                        "first": "Sebastian",
                        "middle": [],
                        "last": "Riedel",
                        "suffix": ""
                    },
                    {
                        "first": "Limin",
                        "middle": [],
                        "last": "Yao",
                        "suffix": ""
                    },
                    {
                        "first": "Andrew",
                        "middle": [],
                        "last": "Mccallum",
                        "suffix": ""
                    }
                ],
                "year": 2010,
                "venue": "Machine Learning and Knowledge Discovery in Databases",
                "volume": "",
                "issue": "",
                "pages": "148--163",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Sebastian Riedel, Limin Yao, and Andrew McCallum. 2010. Modeling relations and their mentions with- out labeled text. In Machine Learning and Knowledge Discovery in Databases, pages 148-163. Springer.",
                "links": null
            },
            "BIBREF13": {
                "ref_id": "b13",
                "title": "Featurebased models for improving the quality of noisy training data for relation extraction",
                "authors": [
                    {
                        "first": "Benjamin",
                        "middle": [],
                        "last": "Roth",
                        "suffix": ""
                    },
                    {
                        "first": "Dietrich",
                        "middle": [],
                        "last": "Klakow",
                        "suffix": ""
                    }
                ],
                "year": 2013,
                "venue": "Proceedings of the 22nd ACM International Conference on Information and Knowledge Management (CIKM)",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Benjamin Roth and Dietrich Klakow. 2013. Feature- based models for improving the quality of noisy train- ing data for relation extraction. In Proceedings of the 22nd ACM International Conference on Information and Knowledge Management (CIKM). ACM.",
                "links": null
            },
            "BIBREF14": {
                "ref_id": "b14",
                "title": "Generalizing from freebase and patterns using distant supervision for slot filling",
                "authors": [
                    {
                        "first": "Benjamin",
                        "middle": [],
                        "last": "Roth",
                        "suffix": ""
                    },
                    {
                        "first": "Grzegorz",
                        "middle": [],
                        "last": "Chrupala",
                        "suffix": ""
                    },
                    {
                        "first": "Michael",
                        "middle": [],
                        "last": "Wiegand",
                        "suffix": ""
                    },
                    {
                        "first": "Mittul",
                        "middle": [],
                        "last": "Singh",
                        "suffix": ""
                    },
                    {
                        "first": "Dietrich",
                        "middle": [],
                        "last": "Klakow",
                        "suffix": ""
                    }
                ],
                "year": 2012,
                "venue": "Proceedings of the Text Analysis Conference",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Benjamin Roth, Grzegorz Chrupala, Michael Wiegand, Mittul Singh, and Dietrich Klakow. 2012. General- izing from freebase and patterns using distant supervi- sion for slot filling. In Proceedings of the Text Analysis Conference (TAC).",
                "links": null
            },
            "BIBREF15": {
                "ref_id": "b15",
                "title": "Multi-instance multilabel learning for relation extraction",
                "authors": [
                    {
                        "first": "Mihai",
                        "middle": [],
                        "last": "Surdeanu",
                        "suffix": ""
                    },
                    {
                        "first": "Julie",
                        "middle": [],
                        "last": "Tibshirani",
                        "suffix": ""
                    },
                    {
                        "first": "Ramesh",
                        "middle": [],
                        "last": "Nallapati",
                        "suffix": ""
                    },
                    {
                        "first": "Christopher D",
                        "middle": [],
                        "last": "Manning",
                        "suffix": ""
                    }
                ],
                "year": 2012,
                "venue": "Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning",
                "volume": "",
                "issue": "",
                "pages": "455--465",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Mihai Surdeanu, Julie Tibshirani, Ramesh Nallapati, and Christopher D Manning. 2012. Multi-instance multi- label learning for relation extraction. In Proceedings of the 2012 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning, pages 455-465. Associa- tion for Computational Linguistics.",
                "links": null
            },
            "BIBREF16": {
                "ref_id": "b16",
                "title": "Reducing wrong labels in distant supervision for relation extraction",
                "authors": [
                    {
                        "first": "Shingo",
                        "middle": [],
                        "last": "Takamatsu",
                        "suffix": ""
                    },
                    {
                        "first": "Issei",
                        "middle": [],
                        "last": "Sato",
                        "suffix": ""
                    },
                    {
                        "first": "Hiroshi",
                        "middle": [],
                        "last": "Nakagawa",
                        "suffix": ""
                    }
                ],
                "year": 2012,
                "venue": "Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics: Long Papers",
                "volume": "1",
                "issue": "",
                "pages": "721--729",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Shingo Takamatsu, Issei Sato, and Hiroshi Nakagawa. 2012. Reducing wrong labels in distant supervi- sion for relation extraction. In Proceedings of the 50th Annual Meeting of the Association for Compu- tational Linguistics: Long Papers -Volume 1, ACL '12, pages 721-729, Stroudsburg, PA, USA. Associ- ation for Computational Linguistics.",
                "links": null
            },
            "BIBREF17": {
                "ref_id": "b17",
                "title": "Collective cross-document relation extraction without labelled data",
                "authors": [
                    {
                        "first": "Limin",
                        "middle": [],
                        "last": "Yao",
                        "suffix": ""
                    },
                    {
                        "first": "Sebastian",
                        "middle": [],
                        "last": "Riedel",
                        "suffix": ""
                    },
                    {
                        "first": "Andrew",
                        "middle": [],
                        "last": "Mccallum",
                        "suffix": ""
                    }
                ],
                "year": 2010,
                "venue": "Proceedings of the 2010 Conference on Empirical Methods in Natural Language Processing",
                "volume": "",
                "issue": "",
                "pages": "1013--1023",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Limin Yao, Sebastian Riedel, and Andrew McCallum. 2010. Collective cross-document relation extraction without labelled data. In Proceedings of the 2010 Con- ference on Empirical Methods in Natural Language Processing, pages 1013-1023. Association for Com- putational Linguistics.",
                "links": null
            }
        },
        "ref_entries": {
            "FIGREF0": {
                "text": "Hierarchical topic models. Intertext model (left) and feature model (right).",
                "type_str": "figure",
                "num": null,
                "uris": null
            },
            "FIGREF1": {
                "text": "The weight vectors are averaged over 20 iterations.",
                "type_str": "figure",
                "num": null,
                "uris": null
            },
            "FIGREF2": {
                "text": "Score combination by non-dominated sorting: Circles indicate patterns on the Pareto-frontier, which are ranked highest. They are followed by the triangles, the square indicates the lowest ranked pattern in this example.For the patterns of the form[ARG1]  context [ARG2], we compute the following scores:\u2022 Maximum Likelihood (MLE): n(pat,r)\u2022P (r|s,\u03b8) n(pat)\u2022(P (r|s,\u03b8)+P (N IL|s,\u03b8))",
                "type_str": "figure",
                "num": null,
                "uris": null
            },
            "FIGREF3": {
                "text": "Precision at recall levels.",
                "type_str": "figure",
                "num": null,
                "uris": null
            },
            "FIGREF4": {
                "text": "Top-scored patterns for maximum likelihood (MLE) and the interpolation (perc+hier itpl) method. Inexact patterns are marked by *.",
                "type_str": "figure",
                "num": null,
                "uris": null
            }
        }
    }
}