File size: 90,318 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
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
{
    "paper_id": "D13-1017",
    "header": {
        "generated_with": "S2ORC 1.0.0",
        "date_generated": "2023-01-19T16:42:05.161161Z"
    },
    "title": "Appropriately Incorporating Statistical Significance in PMI",
    "authors": [
        {
            "first": "Om",
            "middle": [
                "P"
            ],
            "last": "Damani",
            "suffix": "",
            "affiliation": {
                "laboratory": "",
                "institution": "IIT",
                "location": {
                    "settlement": "Bombay",
                    "country": "India"
                }
            },
            "email": "damani@cse.iitb.ac.in"
        },
        {
            "first": "Shweta",
            "middle": [],
            "last": "Ghonge",
            "suffix": "",
            "affiliation": {
                "laboratory": "",
                "institution": "IIT",
                "location": {
                    "settlement": "Bombay",
                    "country": "India"
                }
            },
            "email": "shwetaghonge@cse.iitb.ac.in"
        }
    ],
    "year": "",
    "venue": null,
    "identifiers": {},
    "abstract": "Two recent measures incorporate the notion of statistical significance in basic PMI formulation. In some tasks, we find that the new measures perform worse than the PMI. Our analysis shows that while the basic ideas in incorporating statistical significance in PMI are reasonable, they have been applied slightly inappropriately. By fixing this, we get new measures that improve performance over not just PMI but on other popular co-occurrence measures as well. In fact, the revised measures perform reasonably well compared with more resource intensive non co-occurrence based methods also.",
    "pdf_parse": {
        "paper_id": "D13-1017",
        "_pdf_hash": "",
        "abstract": [
            {
                "text": "Two recent measures incorporate the notion of statistical significance in basic PMI formulation. In some tasks, we find that the new measures perform worse than the PMI. Our analysis shows that while the basic ideas in incorporating statistical significance in PMI are reasonable, they have been applied slightly inappropriately. By fixing this, we get new measures that improve performance over not just PMI but on other popular co-occurrence measures as well. In fact, the revised measures perform reasonably well compared with more resource intensive non co-occurrence based methods also.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Abstract",
                "sec_num": null
            }
        ],
        "body_text": [
            {
                "text": "The notion of word association is used in many language processing and information retrieval applications and it is important to have low-cost, highquality association measures. Lexical co-occurrence based word association measures are popular because they are computationally efficient and they can be applied to any language easily. One of the most popular co-occurrence measure is Pointwise Mutual Information (PMI) (Church and Hanks, 1989) .",
                "cite_spans": [
                    {
                        "start": 419,
                        "end": 443,
                        "text": "(Church and Hanks, 1989)",
                        "ref_id": "BIBREF4"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "One of the limitations of PMI is that it only works with relative probabilities and ignores the absolute amount of evidence. To overcome this, recently two new measures have been proposed that incorporate the notion of statistical significance in basic PMI formulation. In (Washtell and Markert, 2009) , statistical significance is introduced in PMI sig by multiplying PMI value with the square root of the evidence. In contrast, in (Damani, 2013) , cPMId is introduced by bounding the probability of observing a given deviation between a given word pair's cooccurrence count and its expected value under a null model where with each word a global unigram generation probability is associated. In Table 1 , we give the definitions of PMI, PMI sig , and cPMId.",
                "cite_spans": [
                    {
                        "start": 273,
                        "end": 301,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    },
                    {
                        "start": 433,
                        "end": 447,
                        "text": "(Damani, 2013)",
                        "ref_id": "BIBREF6"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 697,
                        "end": 704,
                        "text": "Table 1",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "While these new measures perform better than PMI on some of the tasks, on many other tasks, we find that the new measures perform worse than the PMI. In Table 3 , we show how these measures perform compared to PMI on four different tasks. We find that PMI sig degrades performance in three out of these four tasks while cPMId degrades performance in two out of these four tasks. The experimental details and discussion are given in Section 4.2.",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 153,
                        "end": 160,
                        "text": "Table 3",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "Our analysis shows that while the basic ideas in incorporating statistical significance are reasonable, they have been applied slightly inappropriately. By fixing this, we get new measures that improve performance over not just PMI, but also on other popular co-occurrence measures on most of these tasks. In fact, the revised measures perform reasonably well compared with more resource intensive non cooccurrence based methods also.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Introduction",
                "sec_num": "1"
            },
            {
                "text": "In (Washtell and Markert, 2009) , it is assumed that the statistical significance of a word pair association is proportional to the square root of the evidence.",
                "cite_spans": [
                    {
                        "start": 3,
                        "end": 31,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Adapting PMI for Statistical Significance",
                "sec_num": "2"
            },
            {
                "text": "The question of what constitutes the evidence is answered by taking the lesser of the frequencies of the two words in the word pair, since at most that many pairings are possible. Hence the PMI value is multi-",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Adapting PMI for Statistical Significance",
                "sec_num": "2"
            },
            {
                "text": "Revised Formula PMI (Church and Hanks, 1989 )",
                "cite_spans": [
                    {
                        "start": 20,
                        "end": 43,
                        "text": "(Church and Hanks, 1989",
                        "ref_id": "BIBREF4"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "log f (x,y) f (x) * f (y)/W",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "PMIsig (Washtell and Markert, 2009) ",
                "cite_spans": [
                    {
                        "start": 7,
                        "end": 35,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "log f (x,y) f (x) * f (y)/W * \u221a min(f(x),f(y)) PMIs: log f (x,y) f (x) * f (y)/W * \u221a max(f(x),f(y)) cPMId (Damani, 2013) log d(x,y) d(x)*d(y)/D+ \u221a d(x) * ln \u03b4 (\u22122.0) sPMId: log d(x,y) max(d(x),d(y))*min(d(x),d(y))/D+ \u221a max(d(x),d(y)) * ln \u03b4 (\u22122.0) Terminology: W",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "Total number of words in the corpus D Total number of documents in the corpus f (x), f (y) unigram frequencies of x, y respectively in the corpus d(x), d(y) Total number of documents in the corpus containing at least one occurrence of x and y respectively f (x, y)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "Span-constrained (x, y) word pair frequency in the corpus d(x, y) Total number of documents in the corpus having at-least one span-constrained occurrence of the word pair (x, y) \u03b4 a parameter varying between 0 and 1 Table 1 : Definitions of PMI and its statistically significant adaptations. The sub-parts in bold represent the changes between the original formulas and the revised formulas. The product",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 216,
                        "end": 223,
                        "text": "Table 1",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "max(d(x), d(y)) * min(d(x), d(y))",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "in sPMId formula can be simplified to f (x) * f (y), however, we left it this way to emphasize the transformation from cPMId.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "plied by min(f (x), f (y)) to get PMI sig . In (Damani, 2013), statistical significance is introduced by bounding the probability of observing a given number of word-pair occurrences in the corpus, just by chance, under a null model of independent unigram occurrences. For this computation, one needs to decide what constitutes a random trial when looking for a word-pair occurrence. Is it the occurrence of the first word (say x) in the pair, or the second (say y). In (Damani, 2013), occurrences of x are arbitrarily chosen to represent the sites of the random trial. Using Hoeffdings Inequality:",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "P [f (x, y) \u2265 f (x) * f (y)/W + f (x) * t] \u2264 exp(\u22122 * f (x) * t 2 )",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "By setting t = ln \u03b4/(\u22122 * f (x)), we get \u03b4 as an upper bound on probability of observing more than f (x) * f (y)/W + f (x) * t bigram occurrences in the corpus, just by chance. Based on this Corpus Level Significant PMI(cPMI) is defined as:",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "cP M I(x, y) = log f (x, y) f (x) * f (y)/W + f (x) * t = log f (x, y) f (x) * f (y)/W + f (x) * ln \u03b4/(\u22122)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "In (Damani, 2013), several variants of cPMI are introduced that incorporate different notions of statistical significance. Of these Corpus Level Significant PMI based on Document count(cPMId -defined in Table 1 ) is found to be the best performing, and hence we consider this variant only in this work.",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 203,
                        "end": 210,
                        "text": "Table 1",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Formula",
                "sec_num": null
            },
            {
                "text": "While considering statistical significance, one has to decide what constitutes a random trial. When looking for a word-pair (x, y)'s occurrences, y can potentially occur near each occurrence of x, or x can potentially occur near each occurrence of y. Which of these two set of occurrences should be considered the sites of random trial. We believe that the occurrences of the more frequent of x and y should be considered, since near each of these occurrences the other word could have occurred. Hence f (x) and f (y) in cPMI definition should be replaced with max(f (x), f (y)) and min(f (x), f (y)) respectively. Similarly, d(x) and d(y) in cPMId formula should be replaced with max(d(x), d(y)) and min(d(x), d(y)) respectively to give a new measure Significant PMI based on Document count(sPMId).",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Choice of Random Trial",
                "sec_num": "2.1"
            },
            {
                "text": "Using the same logic, min(f (x), f (y)) in PMI sig formula should be replaced with max(f (x), f (y)) to give the formula for a new measure PMI-significant(PMIs). The definitions of sPMId and PMIs are also given in Table 1 .",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 214,
                        "end": 221,
                        "text": "Table 1",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Choice of Random Trial",
                "sec_num": "2.1"
            },
            {
                "text": "There are three main types of word association measures: Knowledge based, Distributional Similarity based, and Lexical Co-occurrence based.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Based on Firth's You shall know a word by the company it keeps (Firth, 1957) , distributional similarity based measures characterize a word by the distribution of other words around it and compare Method Formula",
                "cite_spans": [
                    {
                        "start": 63,
                        "end": 76,
                        "text": "(Firth, 1957)",
                        "ref_id": "BIBREF10"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "ChiSquare (\u03c7 2 ) i,j (f (i,j)\u2212Ef (i,j)) 2 Ef (i,j)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Dice (Dice, 1945) f",
                "cite_spans": [
                    {
                        "start": 5,
                        "end": 17,
                        "text": "(Dice, 1945)",
                        "ref_id": "BIBREF7"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "(x,y) f (x)+f (y)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "GoogleDistance (L.Cilibrasi and Vitany, 2007",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": ") max(log d(x),log d(y))\u2212log d(x,y) log D\u2212min(log d(x),log d(y))",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Jaccard (Jaccard, 1912) f",
                "cite_spans": [
                    {
                        "start": 8,
                        "end": 23,
                        "text": "(Jaccard, 1912)",
                        "ref_id": "BIBREF15"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "(x,y) f (x)+f (y)\u2212f (x,y)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "LLR (Dunning, 1993) x \u2208 {x, \u00acx} y \u2208 {y, \u00acy}",
                "cite_spans": [
                    {
                        "start": 4,
                        "end": 19,
                        "text": "(Dunning, 1993)",
                        "ref_id": "BIBREF8"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "f (x , y )log f (x ,y ) f (x )f (y )",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "nPMI (Bouma, 2009) ",
                "cite_spans": [
                    {
                        "start": 5,
                        "end": 18,
                        "text": "(Bouma, 2009)",
                        "ref_id": "BIBREF2"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "log f (x,y) f (x) * f (y)/W log 1 f (x,y)/W",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Ochiai (Janson and Vegelius, 1981) f Daille, 1994) log",
                "cite_spans": [
                    {
                        "start": 7,
                        "end": 34,
                        "text": "(Janson and Vegelius, 1981)",
                        "ref_id": "BIBREF16"
                    },
                    {
                        "start": 37,
                        "end": 50,
                        "text": "Daille, 1994)",
                        "ref_id": "BIBREF5"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "(x,y) \u221a f (x)f (y) PMI 2 (",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "f (x,y) f (x) * f (y)/W 1 f (x,y)/W = log f (x,y) 2 f (x) * f (y)",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Simpson (Simpson, 1943) f",
                "cite_spans": [
                    {
                        "start": 8,
                        "end": 23,
                        "text": "(Simpson, 1943)",
                        "ref_id": "BIBREF26"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "(x,y) min(f (x),f (y))",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "SCI (Washtell and Markert, 2009) f (Li et al., 2006) 0.82 ESA (Gabrilovich and Markovitch, 2007) 0.74 (reimplemented in (Yeh et al., 2009 WordNet::Similarity (Recchia and Jones, 2009) 0.70 0.87 PMI-IR3 (using context) (Turney, 2001) 0.73 Table 3 : 5-fold cross-validation results for different co-occurrence measures. The results for the best, and second best co-occurrence measures for each data-set is shown in bold and underline respectively. Except GoogleDistance and LLR, all results for all co-occurrence measures are statistically significant at p = .05. For each task, the best known result for different non co-occurrence based methods is also shown.",
                "cite_spans": [
                    {
                        "start": 4,
                        "end": 32,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    },
                    {
                        "start": 35,
                        "end": 52,
                        "text": "(Li et al., 2006)",
                        "ref_id": "BIBREF20"
                    },
                    {
                        "start": 62,
                        "end": 96,
                        "text": "(Gabrilovich and Markovitch, 2007)",
                        "ref_id": "BIBREF12"
                    },
                    {
                        "start": 120,
                        "end": 137,
                        "text": "(Yeh et al., 2009",
                        "ref_id": "BIBREF32"
                    },
                    {
                        "start": 158,
                        "end": 183,
                        "text": "(Recchia and Jones, 2009)",
                        "ref_id": "BIBREF25"
                    },
                    {
                        "start": 218,
                        "end": 232,
                        "text": "(Turney, 2001)",
                        "ref_id": "BIBREF28"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 238,
                        "end": 245,
                        "text": "Table 3",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "(x,y) f (x) \u221a f (y) T-test f (x,y)\u2212Ef (x,y) f (x,y)(1\u2212 f (x,y) W )",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "two words for distributional similarity Wandmacher et al., 2008; Bollegala et al., 2007; Chen et al., 2006) . They are also used for modeling the meaning of a phrase or a sentence (Grefenstette and Sadrzadeh, 2011; Wartena, 2013; Mitchell, 2011; G. Dinu and Baroni, 2013; Kartsaklis et al., 2013) . Knowledge-based measures use knowledgesources like thesauri, semantic networks, or taxonomies (Milne and Witten, 2008; Hughes and Ramage, 2007; Gabrilovich and Markovitch, 2007; Yeh et al., 2009; Strube and Ponzetto, 2006; Finkelstein et al., 2002; Liberman and Markovitch, 2009) .",
                "cite_spans": [
                    {
                        "start": 40,
                        "end": 64,
                        "text": "Wandmacher et al., 2008;",
                        "ref_id": "BIBREF29"
                    },
                    {
                        "start": 65,
                        "end": 88,
                        "text": "Bollegala et al., 2007;",
                        "ref_id": "BIBREF1"
                    },
                    {
                        "start": 89,
                        "end": 107,
                        "text": "Chen et al., 2006)",
                        "ref_id": "BIBREF3"
                    },
                    {
                        "start": 180,
                        "end": 214,
                        "text": "(Grefenstette and Sadrzadeh, 2011;",
                        "ref_id": "BIBREF13"
                    },
                    {
                        "start": 215,
                        "end": 229,
                        "text": "Wartena, 2013;",
                        "ref_id": "BIBREF30"
                    },
                    {
                        "start": 230,
                        "end": 245,
                        "text": "Mitchell, 2011;",
                        "ref_id": "BIBREF23"
                    },
                    {
                        "start": 246,
                        "end": 271,
                        "text": "G. Dinu and Baroni, 2013;",
                        "ref_id": "BIBREF11"
                    },
                    {
                        "start": 272,
                        "end": 296,
                        "text": "Kartsaklis et al., 2013)",
                        "ref_id": "BIBREF17"
                    },
                    {
                        "start": 393,
                        "end": 417,
                        "text": "(Milne and Witten, 2008;",
                        "ref_id": "BIBREF22"
                    },
                    {
                        "start": 418,
                        "end": 442,
                        "text": "Hughes and Ramage, 2007;",
                        "ref_id": "BIBREF14"
                    },
                    {
                        "start": 443,
                        "end": 476,
                        "text": "Gabrilovich and Markovitch, 2007;",
                        "ref_id": "BIBREF12"
                    },
                    {
                        "start": 477,
                        "end": 494,
                        "text": "Yeh et al., 2009;",
                        "ref_id": "BIBREF32"
                    },
                    {
                        "start": 495,
                        "end": 521,
                        "text": "Strube and Ponzetto, 2006;",
                        "ref_id": "BIBREF27"
                    },
                    {
                        "start": 522,
                        "end": 547,
                        "text": "Finkelstein et al., 2002;",
                        "ref_id": "BIBREF9"
                    },
                    {
                        "start": 548,
                        "end": 578,
                        "text": "Liberman and Markovitch, 2009)",
                        "ref_id": "BIBREF21"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Co-occurrence based measures (Pecina and Schlesinger, 2006 ) simply rely on unigram and bigram frequencies of the words in a pair. In this work, our focus is on the co-occurrence based measures, since they are resource-light and can easily be used for resource-scarce languages.",
                "cite_spans": [
                    {
                        "start": 29,
                        "end": 58,
                        "text": "(Pecina and Schlesinger, 2006",
                        "ref_id": "BIBREF24"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Related Work",
                "sec_num": "3"
            },
            {
                "text": "Co-occurrence based measures of association between two entities are used in several domains like ecology, psychology, medicine, language processing, etc. To compare the performance of our newly introduced measures with other co-occurrence measures, we have selected a number of popular co-occurrence measures like ChiSquare (\u03c7 2 ), Dice (Dice, 1945) , GoogleDistance (L.Cilibrasi and Vitany, 2007), Jaccard (Jaccard, 1912) , LLR (Dunning, 1993), Simpson (Simpson, 1943) , and T-test from these domains.",
                "cite_spans": [
                    {
                        "start": 338,
                        "end": 350,
                        "text": "(Dice, 1945)",
                        "ref_id": "BIBREF7"
                    },
                    {
                        "start": 408,
                        "end": 423,
                        "text": "(Jaccard, 1912)",
                        "ref_id": "BIBREF15"
                    },
                    {
                        "start": 455,
                        "end": 470,
                        "text": "(Simpson, 1943)",
                        "ref_id": "BIBREF26"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Co-occurrence Measures being Compared",
                "sec_num": "3.1"
            },
            {
                "text": "In addition to these popular measures, we also experiment with other known variations of PMI like nPMI (Bouma, 2009) , PMI 2 (Daille, 1994) , Ochiai (Janson and Vegelius, 1981) , and SCI (Washtell and Markert, 2009) . Since PMI 2 is a monotonic transformation of Ochiai, we present their results together. In Table 2 , we present the definitions of these measures. While the motivation given for SCI in (Washtell and Markert, 2009) is slightly different, in light of the discussion in Section 2.1, we can assume that SCI is PMI adapted for statistical significance (multiplied by \u221a f(y)), where the site of random trial is taken to be the occurrences of the second word y, instead of the less frequent word, as in the case of PMI sig .",
                "cite_spans": [
                    {
                        "start": 103,
                        "end": 116,
                        "text": "(Bouma, 2009)",
                        "ref_id": "BIBREF2"
                    },
                    {
                        "start": 125,
                        "end": 139,
                        "text": "(Daille, 1994)",
                        "ref_id": "BIBREF5"
                    },
                    {
                        "start": 149,
                        "end": 176,
                        "text": "(Janson and Vegelius, 1981)",
                        "ref_id": "BIBREF16"
                    },
                    {
                        "start": 187,
                        "end": 215,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    },
                    {
                        "start": 403,
                        "end": 431,
                        "text": "(Washtell and Markert, 2009)",
                        "ref_id": "BIBREF31"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 309,
                        "end": 316,
                        "text": "Table 2",
                        "ref_id": "TABREF0"
                    }
                ],
                "eq_spans": [],
                "section": "Co-occurrence Measures being Compared",
                "sec_num": "3.1"
            },
            {
                "text": "When counting co-occurrences, we only consider the non-overlapping span-constrained occurrences. The span of a word-pair's occurrence is the direction-independent distance between the occurrences of the members of the pair. We consider only those co-occurrences where span is less than a given threshold. Therefore, span threshold is a parameter for all the co-occurrence measures being considered.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Co-occurrence Measures being Compared",
                "sec_num": "3.1"
            },
            {
                "text": "Having introduced the revised measures PMIs and sPMId, we need to evaluate the performance of these measures compared to PMI and the original measures introducing significance. In addition, we also wish to compare the performance of these measures with other co-occurrence measures. To compare the performance of these measures with more resource heavy non co-occurrence based measures, we have chosen those tasks and datasets on which published results exist for distributional similarity and knowledge based word association measures.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Performance Evaluation",
                "sec_num": "4"
            },
            {
                "text": "We evaluate these measures on three tasks: Sentence Similarity(65 sentence-pairs from (Li et al., 2006) ), Synonym Selection(50 questions ESL (Turney, 2001 ) and 80 questions TOEFL (Landauer and Dutnais, 1997) datasets), and, Semantic Relatedness(353 words Wordsim (Finkelstein et al., 2002) dataset).",
                "cite_spans": [
                    {
                        "start": 86,
                        "end": 103,
                        "text": "(Li et al., 2006)",
                        "ref_id": "BIBREF20"
                    },
                    {
                        "start": 142,
                        "end": 155,
                        "text": "(Turney, 2001",
                        "ref_id": "BIBREF28"
                    },
                    {
                        "start": 265,
                        "end": 291,
                        "text": "(Finkelstein et al., 2002)",
                        "ref_id": "BIBREF9"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "For each of these tasks, gold standard human judgment results exist. For sentence similarity, following (Li et al., 2006) , we evaluate a measure by the Pearsons correlation between the ranking produced by the measure and the human ranking. For synonym selection, we compute the percentage of correct answers, since there is a unique answer for each challenge word in the datasets. Semantic relatedness has been evaluated by Spearman's rank correlation with human judgment instead of Pearsons correlation in literature and we follow the same practice to make results comparable.",
                "cite_spans": [
                    {
                        "start": 104,
                        "end": 121,
                        "text": "(Li et al., 2006)",
                        "ref_id": "BIBREF20"
                    }
                ],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "For sentence similarity detection, the algorithm used by us (Li et al., 2006) assumes that the association scores are between 0 and 1. Hence we normalize the value produced by each measure using z)  brass  metal  plastic  15923  125088  24985  228  75  14  24  40  30  twist  intertwine curl  11407  153  2047  1  9  7  17  61  41  saucer  dish  frisbee  2091  12453  1186  5  1  9  14  21  18  mass  lump  element  90398  1595  43321  14  189  4  10  29  15  applause  approval  friends  1998  19673  11689  8  6  9  11  29  28  confession statement plea  7687  47299  5232  76  12  18  22  45  26  swing  sway  bounce  33580  2994  4462  13  17  7  8  24  21  sheet  leaf  book  20470  20979  586581  20  194  7  2  7  12   Table 4 : Details of ESL word-pairs, correctness of whose answers changes between PMI sig and PMIs. Except for the gray-row, for all other questions, incorrect answers becomes correct on using PMIs instead of PMI sig , and vice-versa for the gray-row. The association values have been suitably scaled for readability. To save space, of the four choices, options not selected by either of the methods have been omitted. These results are for a 10 word span.",
                "cite_spans": [
                    {
                        "start": 60,
                        "end": 77,
                        "text": "(Li et al., 2006)",
                        "ref_id": "BIBREF20"
                    }
                ],
                "ref_spans": [
                    {
                        "start": 195,
                        "end": 733,
                        "text": "z)  brass  metal  plastic  15923  125088  24985  228  75  14  24  40  30  twist  intertwine curl  11407  153  2047  1  9  7  17  61  41  saucer  dish  frisbee  2091  12453  1186  5  1  9  14  21  18  mass  lump  element  90398  1595  43321  14  189  4  10  29  15  applause  approval  friends  1998  19673  11689  8  6  9  11  29  28  confession statement plea  7687  47299  5232  76  12  18  22  45  26  swing  sway  bounce  33580  2994  4462  13  17  7  8  24  21  sheet  leaf  book  20470  20979  586581  20  194  7  2  7  12   Table 4",
                        "ref_id": "TABREF0"
                    }
                ],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "Challenge x Option y (correct) Option z (incorrect) f (x) f (y) f (z) f (x, y) f (x, z) PMI sig (x, y) PMI sig (x, z) PMIs (x, y) PMIs (x,",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "max-min normalization:",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "v = v \u2212 min max \u2212 min",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "where max and min are computed over all association scores for the entire task for a given measure.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Task Details",
                "sec_num": "4.1"
            },
            {
                "text": "We use a 1.24 Gigawords Wikipedia corpus for getting co-occurrence statistics. Since co-occurrence methods have span-threshold as a parameter, we follow the standard methodology of five-fold cross validation. Note that, in addition to span-threshold, cP-MId and sPMId have an additional parameter \u03b4.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Experimental Results",
                "sec_num": "4.2"
            },
            {
                "text": "In Table 3 , we present the performance of all the co-occurrence measures considered on all the tasks. Note that, except GoogleDistance and LLR, all results for all co-occurrence measures are statistically significant at p = .05. For completeness of comparison, we also include the best known results from literature for different non co-occurrence based word association measures on these tasks.",
                "cite_spans": [],
                "ref_spans": [
                    {
                        "start": 3,
                        "end": 10,
                        "text": "Table 3",
                        "ref_id": null
                    }
                ],
                "eq_spans": [],
                "section": "Experimental Results",
                "sec_num": "4.2"
            },
            {
                "text": "We find that on average, PMI sig and cPMId, the recently introduced measures that incorporate significance in PMI, do not perform better than PMI on the given datasets. Both of them perform worse than PMI on three out of four datasets. By appropriately incorporating significance, we get new measures PMIs and sPMId that perform better than PMI(also PMI sig and cPMId respectively) on most datasets. PMIs improves performance over PMI on three out of four datasets, while sPMId improves performance on all four datasets.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Performance Analysis and Conclusions",
                "sec_num": "4.3"
            },
            {
                "text": "The performance improvement of PMIs over PMI sig and of sPMId over cPMId, is not random. For example, on the ESL dataset, while the percentage of correct answers increases from 58 to 66 from PMI sig to PMIs, it is not the case that on moving from PMI sig to PMIs, several correct answers become incorrect and an even larger number of incorrect answers become correct. As shown in Table 4, only one correct answers become incorrect while seven incorrect answers get corrected. The same trend holds for most parameters values, and for moving from cPMId to sPMId. This substantiates the claim that the improvement is not random, but due to the appropriate incorporation of significance, as discussed in Section 2.1.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Performance Analysis and Conclusions",
                "sec_num": "4.3"
            },
            {
                "text": "PMIs and sPMId perform better than not just PMI, but they perform better than all popular cooccurrence measures on most of these tasks. When compared with any other co-occurrence measure, on three out of four datasets each, both PMIs and sPMId perform better than that measure. In fact, PMIs and sPMId perform reasonably well compared with more resource intensive non co-occurrence based methods as well. Note that different non cooccurrence based measures perform well on different tasks. We are comparing the performance of a single measure (say sPMId or PMIs) against the best measure for each task.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Performance Analysis and Conclusions",
                "sec_num": "4.3"
            }
        ],
        "back_matter": [
            {
                "text": "We thank Dipak Chaudhari for his help with the implementation.",
                "cite_spans": [],
                "ref_spans": [],
                "eq_spans": [],
                "section": "Acknowledgements",
                "sec_num": null
            }
        ],
        "bib_entries": {
            "BIBREF0": {
                "ref_id": "b0",
                "title": "A study on similarity and relatedness using distributional and wordnet-based approaches",
                "authors": [
                    {
                        "first": "Eneko",
                        "middle": [],
                        "last": "Agirre",
                        "suffix": ""
                    },
                    {
                        "first": "Enrique",
                        "middle": [],
                        "last": "Alfonseca",
                        "suffix": ""
                    },
                    {
                        "first": "Keith",
                        "middle": [],
                        "last": "Hall",
                        "suffix": ""
                    },
                    {
                        "first": "Jana",
                        "middle": [],
                        "last": "Kravalova",
                        "suffix": ""
                    },
                    {
                        "first": "Marius",
                        "middle": [],
                        "last": "Pasca",
                        "suffix": ""
                    },
                    {
                        "first": "Aitor",
                        "middle": [],
                        "last": "Soroa",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "NAACL-HLT 2009, Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Eneko Agirre, Enrique Alfonseca, Keith Hall, Jana Kravalova, Marius Pasca, and Aitor Soroa. 2009. A study on similarity and relatedness using distributional and wordnet-based approaches. In NAACL-HLT 2009, Conference of the North American Chapter of the As- sociation for Computational Linguistics: Human Lan- guage Technologies.",
                "links": null
            },
            "BIBREF1": {
                "ref_id": "b1",
                "title": "Measuring semantic similarity between words using web search engines",
                "authors": [
                    {
                        "first": "Danushka",
                        "middle": [],
                        "last": "Bollegala",
                        "suffix": ""
                    },
                    {
                        "first": "Yutaka",
                        "middle": [],
                        "last": "Matsuo",
                        "suffix": ""
                    },
                    {
                        "first": "Mitsuru",
                        "middle": [],
                        "last": "Ishizuka",
                        "suffix": ""
                    }
                ],
                "year": 2007,
                "venue": "WWW 2007, The World Wide Web Conference",
                "volume": "",
                "issue": "",
                "pages": "757--766",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Danushka Bollegala, Yutaka Matsuo, and Mitsuru Ishizuka. 2007. Measuring semantic similarity be- tween words using web search engines. In WWW 2007, The World Wide Web Conference, pages 757- 766.",
                "links": null
            },
            "BIBREF2": {
                "ref_id": "b2",
                "title": "Normalized (pointwise) mutual information in collocation extraction, from form to meaning: Processing texts automatically",
                "authors": [
                    {
                        "first": "Gerlof",
                        "middle": [],
                        "last": "Bouma",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "GSCL 2009, Proceedings of the Biennial International Conference of the German Society for Computational Linguistics and Language Technology",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Gerlof Bouma. 2009. Normalized (pointwise) mutual information in collocation extraction, from form to meaning: Processing texts automatically. In GSCL 2009, Proceedings of the Biennial International Con- ference of the German Society for Computational Lin- guistics and Language Technology.",
                "links": null
            },
            "BIBREF3": {
                "ref_id": "b3",
                "title": "Novel association measures using web search with double checking",
                "authors": [
                    {
                        "first": "Hsin-Hsi",
                        "middle": [],
                        "last": "Chen",
                        "suffix": ""
                    },
                    {
                        "first": "Ming-Shun",
                        "middle": [],
                        "last": "Lin",
                        "suffix": ""
                    },
                    {
                        "first": "Yu-Chuan",
                        "middle": [],
                        "last": "Wei",
                        "suffix": ""
                    }
                ],
                "year": 2006,
                "venue": "COLING/ACL 2006, Proceedings of the 21st International Conference on Computational Linguistics and 44th Annual Meeting of the Association for Computational Linguistics",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Hsin-Hsi Chen, Ming-Shun Lin, and Yu-Chuan Wei. 2006. Novel association measures using web search with double checking. In COLING/ACL 2006, Pro- ceedings of the 21st International Conference on Com- putational Linguistics and 44th Annual Meeting of the Association for Computational Linguistics.",
                "links": null
            },
            "BIBREF4": {
                "ref_id": "b4",
                "title": "Word association norms, mutual information and lexicography",
                "authors": [
                    {
                        "first": "Kenneth",
                        "middle": [
                            "Ward"
                        ],
                        "last": "Church",
                        "suffix": ""
                    },
                    {
                        "first": "Patrick",
                        "middle": [],
                        "last": "Hanks",
                        "suffix": ""
                    }
                ],
                "year": 1989,
                "venue": "ACL 1989, Proceedings of the Annual Meeting of the Association for Computational Linguistics",
                "volume": "",
                "issue": "",
                "pages": "76--83",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Kenneth Ward Church and Patrick Hanks. 1989. Word association norms, mutual information and lexicogra- phy. In ACL 1989, Proceedings of the Annual Meet- ing of the Association for Computational Linguistics, pages 76-83.",
                "links": null
            },
            "BIBREF5": {
                "ref_id": "b5",
                "title": "Approche mixte pour l'extraction automatique de terminologie: statistiques lexicales etltres linguistiques",
                "authors": [
                    {
                        "first": "B",
                        "middle": [],
                        "last": "Daille",
                        "suffix": ""
                    }
                ],
                "year": 1994,
                "venue": "",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "B. Daille. 1994. Approche mixte pour l'extraction au- tomatique de terminologie: statistiques lexicales etl- tres linguistiques. Ph.D. thesis, Universitie Paris 7.",
                "links": null
            },
            "BIBREF6": {
                "ref_id": "b6",
                "title": "Improving pointwise mutual information (pmi) by incorporating significant cooccurrence",
                "authors": [
                    {
                        "first": "P",
                        "middle": [],
                        "last": "Om",
                        "suffix": ""
                    },
                    {
                        "first": "",
                        "middle": [],
                        "last": "Damani",
                        "suffix": ""
                    }
                ],
                "year": 2013,
                "venue": "CoNLL 2013, Conference on Computational Natural Language Learning",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Om P. Damani. 2013. Improving pointwise mutual information (pmi) by incorporating significant co- occurrence. In CoNLL 2013, Conference on Compu- tational Natural Language Learning.",
                "links": null
            },
            "BIBREF7": {
                "ref_id": "b7",
                "title": "Measures of the amount of ecological association between species",
                "authors": [
                    {
                        "first": "L",
                        "middle": [
                            "R"
                        ],
                        "last": "Dice",
                        "suffix": ""
                    }
                ],
                "year": 1945,
                "venue": "Ecology",
                "volume": "26",
                "issue": "",
                "pages": "297--302",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "L. R. Dice. 1945. Measures of the amount of ecological association between species. Ecology, 26:297-302.",
                "links": null
            },
            "BIBREF8": {
                "ref_id": "b8",
                "title": "Accurate methods for the statistics of surprise and coincidence",
                "authors": [
                    {
                        "first": "Ted",
                        "middle": [],
                        "last": "Dunning",
                        "suffix": ""
                    }
                ],
                "year": 1993,
                "venue": "Computational Linguistics",
                "volume": "19",
                "issue": "1",
                "pages": "61--74",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Ted Dunning. 1993. Accurate methods for the statistics of surprise and coincidence. Computational Linguis- tics, 19(1):61-74.",
                "links": null
            },
            "BIBREF9": {
                "ref_id": "b9",
                "title": "Placing search in context: the concept revisited",
                "authors": [
                    {
                        "first": "Lev",
                        "middle": [],
                        "last": "Finkelstein",
                        "suffix": ""
                    },
                    {
                        "first": "Evgeniy",
                        "middle": [],
                        "last": "Gabrilovich",
                        "suffix": ""
                    },
                    {
                        "first": "Yossi",
                        "middle": [],
                        "last": "Matias",
                        "suffix": ""
                    },
                    {
                        "first": "Ehud",
                        "middle": [],
                        "last": "Rivlin",
                        "suffix": ""
                    },
                    {
                        "first": "Zach",
                        "middle": [],
                        "last": "Solan",
                        "suffix": ""
                    },
                    {
                        "first": "Gadi",
                        "middle": [],
                        "last": "Wolfman",
                        "suffix": ""
                    },
                    {
                        "first": "Eytan",
                        "middle": [],
                        "last": "Ruppin",
                        "suffix": ""
                    }
                ],
                "year": 2002,
                "venue": "ACM Transactions on Information Systems",
                "volume": "20",
                "issue": "1",
                "pages": "116--131",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Lev Finkelstein, Evgeniy Gabrilovich, Yossi Matias, Ehud Rivlin, Zach Solan, Gadi Wolfman, and Eytan Ruppin. 2002. Placing search in context: the concept revisited. ACM Transactions on Information Systems, 20(1):116-131.",
                "links": null
            },
            "BIBREF10": {
                "ref_id": "b10",
                "title": "A synopsis of linguistics theory. Studies in Linguistic Analysis",
                "authors": [
                    {
                        "first": "J",
                        "middle": [
                            "R"
                        ],
                        "last": "Firth",
                        "suffix": ""
                    }
                ],
                "year": 1957,
                "venue": "",
                "volume": "",
                "issue": "",
                "pages": "1930--1955",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "J. R. Firth. 1957. A synopsis of linguistics theory. Stud- ies in Linguistic Analysis, pages 1930-1955.",
                "links": null
            },
            "BIBREF11": {
                "ref_id": "b11",
                "title": "General estimation and evaluation of compositional distributional semantic models",
                "authors": [
                    {
                        "first": "N",
                        "middle": [],
                        "last": "Pham",
                        "suffix": ""
                    },
                    {
                        "first": "G",
                        "middle": [],
                        "last": "Dinu",
                        "suffix": ""
                    },
                    {
                        "first": "M",
                        "middle": [],
                        "last": "Baroni",
                        "suffix": ""
                    }
                ],
                "year": 2013,
                "venue": "CVSC 2013, Proceedings of the ACL Workshop on Continuous Vector Space Models and their Compositionality",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "N. Pham G. Dinu and M. Baroni. 2013. General esti- mation and evaluation of compositional distributional semantic models. In CVSC 2013, Proceedings of the ACL Workshop on Continuous Vector Space Models and their Compositionality.",
                "links": null
            },
            "BIBREF12": {
                "ref_id": "b12",
                "title": "Computing semantic relatedness using wikipedia-based explicit semantic analysis",
                "authors": [
                    {
                        "first": "Evgeniy",
                        "middle": [],
                        "last": "Gabrilovich",
                        "suffix": ""
                    },
                    {
                        "first": "Shaul",
                        "middle": [],
                        "last": "Markovitch",
                        "suffix": ""
                    }
                ],
                "year": 2007,
                "venue": "IJCAI 2007, International Joint Conference on Artificial Intelligence",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Evgeniy Gabrilovich and Shaul Markovitch. 2007. Com- puting semantic relatedness using wikipedia-based ex- plicit semantic analysis. In IJCAI 2007, International Joint Conference on Artificial Intelligence.",
                "links": null
            },
            "BIBREF13": {
                "ref_id": "b13",
                "title": "Experimental support for a categorical compositional distributional model of meaning",
                "authors": [
                    {
                        "first": "Edward",
                        "middle": [],
                        "last": "Grefenstette",
                        "suffix": ""
                    },
                    {
                        "first": "Mehrnoosh",
                        "middle": [],
                        "last": "Sadrzadeh",
                        "suffix": ""
                    }
                ],
                "year": 2011,
                "venue": "EMNLP 2011, Conference on Empirical Methods on Natural Language Processing",
                "volume": "",
                "issue": "",
                "pages": "1394--1404",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Edward Grefenstette and Mehrnoosh Sadrzadeh. 2011. Experimental support for a categorical compositional distributional model of meaning. In EMNLP 2011, Conference on Empirical Methods on Natural Lan- guage Processing, pages 1394-1404.",
                "links": null
            },
            "BIBREF14": {
                "ref_id": "b14",
                "title": "Lexical semantic relatedness with random graph walks",
                "authors": [
                    {
                        "first": "T",
                        "middle": [],
                        "last": "Hughes",
                        "suffix": ""
                    },
                    {
                        "first": "",
                        "middle": [],
                        "last": "Ramage",
                        "suffix": ""
                    }
                ],
                "year": 2007,
                "venue": "EMNLP 2007, Conference on Empirical Methods on Natural Language Processing",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "T Hughes and D Ramage. 2007. Lexical semantic relat- edness with random graph walks. In EMNLP 2007, Conference on Empirical Methods on Natural Lan- guage Processing.",
                "links": null
            },
            "BIBREF15": {
                "ref_id": "b15",
                "title": "The distribution of the flora of the alpine zone",
                "authors": [
                    {
                        "first": "P",
                        "middle": [],
                        "last": "Jaccard",
                        "suffix": ""
                    }
                ],
                "year": 1912,
                "venue": "New Phytologist",
                "volume": "11",
                "issue": "",
                "pages": "37--50",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "P. Jaccard. 1912. The distribution of the flora of the alpine zone. New Phytologist, 11:37-50.",
                "links": null
            },
            "BIBREF16": {
                "ref_id": "b16",
                "title": "Measures of ecological association",
                "authors": [
                    {
                        "first": "Svante",
                        "middle": [],
                        "last": "Janson",
                        "suffix": ""
                    }
                ],
                "year": 1981,
                "venue": "Oecologia",
                "volume": "49",
                "issue": "",
                "pages": "371--376",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Svante Janson and Jan Vegelius. 1981. Measures of eco- logical association. Oecologia, 49:371-376.",
                "links": null
            },
            "BIBREF17": {
                "ref_id": "b17",
                "title": "Separating disambiguation from composition in distributional semantics",
                "authors": [
                    {
                        "first": "Dimitrios",
                        "middle": [],
                        "last": "Kartsaklis",
                        "suffix": ""
                    },
                    {
                        "first": "Mehrnoosh",
                        "middle": [],
                        "last": "Sadrzadeh",
                        "suffix": ""
                    },
                    {
                        "first": "Stephen",
                        "middle": [],
                        "last": "Pulman",
                        "suffix": ""
                    }
                ],
                "year": 2013,
                "venue": "CoNLL 2013, Conference on Computational Natural Language Learning",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Dimitrios Kartsaklis, Mehrnoosh Sadrzadeh, and Stephen Pulman. 2013. Separating disambiguation from composition in distributional semantics. In CoNLL 2013, Conference on Computational Natural Lan- guage Learning.",
                "links": null
            },
            "BIBREF18": {
                "ref_id": "b18",
                "title": "A solution to platos problem: The latent semantic analysis theory of acquisition, induction, and representation of knowledge",
                "authors": [
                    {
                        "first": "K",
                        "middle": [],
                        "last": "Thomas",
                        "suffix": ""
                    },
                    {
                        "first": "Susan",
                        "middle": [
                            "T"
                        ],
                        "last": "Landauer",
                        "suffix": ""
                    },
                    {
                        "first": "",
                        "middle": [],
                        "last": "Dutnais",
                        "suffix": ""
                    }
                ],
                "year": 1997,
                "venue": "Psychological review",
                "volume": "104",
                "issue": "2",
                "pages": "211--240",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Thomas K Landauer and Susan T. Dutnais. 1997. A so- lution to platos problem: The latent semantic analysis theory of acquisition, induction, and representation of knowledge. Psychological review, 104(2):211-240.",
                "links": null
            },
            "BIBREF19": {
                "ref_id": "b19",
                "title": "The google similarity distance",
                "authors": [
                    {
                        "first": "L",
                        "middle": [],
                        "last": "Rudi",
                        "suffix": ""
                    },
                    {
                        "first": "",
                        "middle": [],
                        "last": "Cilibrasi",
                        "suffix": ""
                    },
                    {
                        "first": "M",
                        "middle": [
                            "B"
                        ],
                        "last": "Paul",
                        "suffix": ""
                    },
                    {
                        "first": "",
                        "middle": [],
                        "last": "Vitany",
                        "suffix": ""
                    }
                ],
                "year": 2007,
                "venue": "Psychological review",
                "volume": "",
                "issue": "3",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Rudi L.Cilibrasi and Paul M.B. Vitany. 2007. The google similarity distance. Psychological review, 19(3).",
                "links": null
            },
            "BIBREF20": {
                "ref_id": "b20",
                "title": "Sentence similarity based on semantic nets and corpus statistics",
                "authors": [
                    {
                        "first": "Yuhua",
                        "middle": [],
                        "last": "Li",
                        "suffix": ""
                    },
                    {
                        "first": "David",
                        "middle": [],
                        "last": "Mclean",
                        "suffix": ""
                    },
                    {
                        "first": "Zuhair",
                        "middle": [
                            "A"
                        ],
                        "last": "Bandar",
                        "suffix": ""
                    },
                    {
                        "first": "James",
                        "middle": [
                            "D"
                        ],
                        "last": "O'shea",
                        "suffix": ""
                    },
                    {
                        "first": "Keeley",
                        "middle": [],
                        "last": "Crockett",
                        "suffix": ""
                    }
                ],
                "year": 2006,
                "venue": "IEEE Transactions on Knowledge and Data Engineering",
                "volume": "18",
                "issue": "8",
                "pages": "1138--1150",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Yuhua Li, David McLean, Zuhair A. Bandar, James D. O'Shea, and Keeley Crockett. 2006. Sentence sim- ilarity based on semantic nets and corpus statistics. IEEE Transactions on Knowledge and Data Engineer- ing, 18(8):1138-1150, August.",
                "links": null
            },
            "BIBREF21": {
                "ref_id": "b21",
                "title": "Compact hierarchical explicit semantic representation",
                "authors": [
                    {
                        "first": "Sonya",
                        "middle": [],
                        "last": "Liberman",
                        "suffix": ""
                    },
                    {
                        "first": "Shaul",
                        "middle": [],
                        "last": "Markovitch",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "WikiAI 2009, Proceedings of the IJCAI Workshop on User-Contributed Knowledge and Artificial Intelligence: An Evolving Synergy",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Sonya Liberman and Shaul Markovitch. 2009. Com- pact hierarchical explicit semantic representation. In WikiAI 2009, Proceedings of the IJCAI Workshop on User-Contributed Knowledge and Artificial Intel- ligence: An Evolving Synergy, Pasadena, CA, July.",
                "links": null
            },
            "BIBREF22": {
                "ref_id": "b22",
                "title": "An effective, lowcost measure of semantic relatedness obtained from wikipedia links",
                "authors": [
                    {
                        "first": "David",
                        "middle": [],
                        "last": "Milne",
                        "suffix": ""
                    },
                    {
                        "first": "Ian",
                        "middle": [
                            "H"
                        ],
                        "last": "Witten",
                        "suffix": ""
                    }
                ],
                "year": 2008,
                "venue": "ACL 2008, Proceedings of the Annual Meeting of the Association for Computational Linguistics",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "David Milne and Ian H. Witten. 2008. An effective, low- cost measure of semantic relatedness obtained from wikipedia links. In ACL 2008, Proceedings of the Annual Meeting of the Association for Computational Linguistics.",
                "links": null
            },
            "BIBREF23": {
                "ref_id": "b23",
                "title": "Composition in Distributional Models of Semantics",
                "authors": [
                    {
                        "first": "Jeffrey",
                        "middle": [],
                        "last": "Mitchell",
                        "suffix": ""
                    }
                ],
                "year": 2011,
                "venue": "",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Jeffrey Mitchell. 2011. Composition in Distributional Models of Semantics. Ph.D. thesis, The University of Edinburgh.",
                "links": null
            },
            "BIBREF24": {
                "ref_id": "b24",
                "title": "Combining association measures for collocation extraction",
                "authors": [
                    {
                        "first": "Pavel",
                        "middle": [],
                        "last": "Pecina",
                        "suffix": ""
                    },
                    {
                        "first": "Pavel",
                        "middle": [],
                        "last": "Schlesinger",
                        "suffix": ""
                    }
                ],
                "year": 2006,
                "venue": "ACL 2006, Proceedings of the Annual Meeting of the Association for Computational Linguistics",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Pavel Pecina and Pavel Schlesinger. 2006. Combin- ing association measures for collocation extraction. In ACL 2006, Proceedings of the Annual Meeting of the Association for Computational Linguistics.",
                "links": null
            },
            "BIBREF25": {
                "ref_id": "b25",
                "title": "More data trumps smarter algorithms: Comparing pointwise mutual information with latent semantic analysis",
                "authors": [
                    {
                        "first": "Gabriel",
                        "middle": [],
                        "last": "Recchia",
                        "suffix": ""
                    },
                    {
                        "first": "Michael",
                        "middle": [
                            "N"
                        ],
                        "last": "Jones",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "Behavior Research Methods",
                "volume": "3",
                "issue": "41",
                "pages": "647--656",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Gabriel Recchia and Michael N. Jones. 2009. More data trumps smarter algorithms: Comparing pointwise mu- tual information with latent semantic analysis. Behav- ior Research Methods, 3(41):647-656.",
                "links": null
            },
            "BIBREF26": {
                "ref_id": "b26",
                "title": "Mammals and the nature of continents",
                "authors": [
                    {
                        "first": "George",
                        "middle": [
                            "G"
                        ],
                        "last": "Simpson",
                        "suffix": ""
                    }
                ],
                "year": 1943,
                "venue": "American Journal of Science",
                "volume": "",
                "issue": "",
                "pages": "1--31",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "George G. Simpson. 1943. Mammals and the nature of continents. American Journal of Science, pages 1-31.",
                "links": null
            },
            "BIBREF27": {
                "ref_id": "b27",
                "title": "Wikirelate! computing semantic relatedness using wikipedia",
                "authors": [
                    {
                        "first": "Michael",
                        "middle": [],
                        "last": "Strube",
                        "suffix": ""
                    },
                    {
                        "first": "Simone",
                        "middle": [
                            "Paolo"
                        ],
                        "last": "Ponzetto",
                        "suffix": ""
                    }
                ],
                "year": 2006,
                "venue": "AAAI 2006, Conference on Artificial Intelligence",
                "volume": "",
                "issue": "",
                "pages": "1419--1424",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Michael Strube and Simone Paolo Ponzetto. 2006. Wikirelate! computing semantic relatedness using wikipedia. In AAAI 2006, Conference on Artificial In- telligence, pages 1419-1424.",
                "links": null
            },
            "BIBREF28": {
                "ref_id": "b28",
                "title": "Mining the web for synonyms: PMI-IR versus LSA on TOEFL",
                "authors": [
                    {
                        "first": "P",
                        "middle": [],
                        "last": "Turney",
                        "suffix": ""
                    }
                ],
                "year": 2001,
                "venue": "ECML 2001, European Conference on Machine Learning",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "P. Turney. 2001. Mining the web for synonyms: PMI- IR versus LSA on TOEFL. In ECML 2001, European Conference on Machine Learning.",
                "links": null
            },
            "BIBREF29": {
                "ref_id": "b29",
                "title": "Does latent semantic analysis reflect human associations",
                "authors": [
                    {
                        "first": "T",
                        "middle": [],
                        "last": "Wandmacher",
                        "suffix": ""
                    },
                    {
                        "first": "E",
                        "middle": [],
                        "last": "Ovchinnikova",
                        "suffix": ""
                    },
                    {
                        "first": "T",
                        "middle": [],
                        "last": "Alexandrov",
                        "suffix": ""
                    }
                ],
                "year": 2008,
                "venue": "ESSLLI 2008",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "T. Wandmacher, E. Ovchinnikova, and T. Alexandrov. 2008. Does latent semantic analysis reflect human associations? In ESSLLI 2008, European Summer School in Logic, Language and Information.",
                "links": null
            },
            "BIBREF30": {
                "ref_id": "b30",
                "title": "Hsh: Estimating semantic similarity of words and short phrases with frequency normalized distance measures",
                "authors": [
                    {
                        "first": "Christian",
                        "middle": [],
                        "last": "Wartena",
                        "suffix": ""
                    }
                ],
                "year": 2013,
                "venue": "SemEval 2013, International Workshop on Semantic Evaluation",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Christian Wartena. 2013. Hsh: Estimating semantic sim- ilarity of words and short phrases with frequency nor- malized distance measures. In SemEval 2013, Inter- national Workshop on Semantic Evaluation.",
                "links": null
            },
            "BIBREF31": {
                "ref_id": "b31",
                "title": "A comparison of windowless and window-based computational association measures as predictors of syntagmatic human associations",
                "authors": [
                    {
                        "first": "Justin",
                        "middle": [],
                        "last": "Washtell",
                        "suffix": ""
                    },
                    {
                        "first": "Katja",
                        "middle": [],
                        "last": "Markert",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "EMNLP 2009, Conference on Empirical Methods on Natural Language Processing",
                "volume": "",
                "issue": "",
                "pages": "628--637",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Justin Washtell and Katja Markert. 2009. A comparison of windowless and window-based computational asso- ciation measures as predictors of syntagmatic human associations. In EMNLP 2009, Conference on Empir- ical Methods on Natural Language Processing, pages 628-637.",
                "links": null
            },
            "BIBREF32": {
                "ref_id": "b32",
                "title": "Wikiwalk: Random walks on wikipedia for semantic relatedness",
                "authors": [
                    {
                        "first": "Eric",
                        "middle": [],
                        "last": "Yeh",
                        "suffix": ""
                    },
                    {
                        "first": "Daniel",
                        "middle": [],
                        "last": "Ramage",
                        "suffix": ""
                    },
                    {
                        "first": "Chris",
                        "middle": [],
                        "last": "Manning",
                        "suffix": ""
                    },
                    {
                        "first": "Eneko",
                        "middle": [],
                        "last": "Agirre",
                        "suffix": ""
                    },
                    {
                        "first": "Aitor",
                        "middle": [],
                        "last": "Soroa",
                        "suffix": ""
                    }
                ],
                "year": 2009,
                "venue": "TextGraphs 2009, Proceedings of the ACL workshop on Graphbased Methods for Natural Language Processing",
                "volume": "",
                "issue": "",
                "pages": "",
                "other_ids": {},
                "num": null,
                "urls": [],
                "raw_text": "Eric Yeh, Daniel Ramage, Chris Manning, Eneko Agirre, and Aitor Soroa. 2009. Wikiwalk: Random walks on wikipedia for semantic relatedness. In TextGraphs 2009, Proceedings of the ACL workshop on Graph- based Methods for Natural Language Processing.",
                "links": null
            }
        },
        "ref_entries": {
            "TABREF0": {
                "html": null,
                "text": "Definition of other co-occurrence measures being compared in this work. The terminology used here is same as that inTable 1, except that E in front of a variable name means the expected value of that variable.",
                "num": null,
                "content": "<table><tr><td>Task</td><td>Semantic Relatedness</td><td>Sentence Similarity</td><td/><td>Synonym Selection</td></tr><tr><td>Dataset</td><td>WordSim</td><td>Li</td><td>ESL</td><td>TOEFL</td></tr><tr><td>Metric</td><td>Spearman Rank</td><td>Pearson Cor-</td><td>Fraction</td><td>Fraction</td></tr><tr><td/><td>Correlation</td><td>relation</td><td>Correct</td><td>Correct</td></tr><tr><td>PMI</td><td>0.68</td><td>0.69</td><td>0.62</td><td>0.59</td></tr><tr><td>PMI sig</td><td>0.67</td><td>0.85</td><td>0.58</td><td>0.56</td></tr><tr><td>cPMId</td><td>0.72</td><td>0.67</td><td>0.56</td><td>0.59</td></tr><tr><td>PMIs</td><td>0.66</td><td>0.85</td><td>0.66</td><td>0.61</td></tr><tr><td>sPMId</td><td>0.72</td><td>0.75</td><td>0.70</td><td>0.61</td></tr><tr><td>ChiSquare (\u03c7 2 )</td><td>0.62</td><td>0.80</td><td>0.62</td><td>0.58</td></tr><tr><td>Dice</td><td>0.58</td><td>0.76</td><td>0.56</td><td>0.57</td></tr><tr><td>GoogleDistance</td><td>0.53</td><td>0.75</td><td>0.09</td><td>0.19</td></tr><tr><td>Jaccard</td><td>0.58</td><td>0.76</td><td>0.56</td><td>0.57</td></tr><tr><td>LLR</td><td>0.50</td><td>0.18</td><td>0.18</td><td>0.27</td></tr><tr><td>nPMI</td><td>0.72</td><td>0.35</td><td>0.54</td><td>0.54</td></tr><tr><td>Ochiai/ PMI 2</td><td>0.62</td><td>0.77</td><td>0.62</td><td>0.60</td></tr><tr><td>SCI</td><td>0.65</td><td>0.85</td><td>0.62</td><td>0.60</td></tr><tr><td>Simpson</td><td>0.59</td><td>0.78</td><td>0.58</td><td>0.57</td></tr><tr><td>TTest</td><td>0.44</td><td>0.63</td><td>0.44</td><td>0.52</td></tr><tr><td>Semantic Net</td><td/><td/><td/><td/></tr></table>",
                "type_str": "table"
            }
        }
    }
}