Document (#32010)

Author

Moffat, A.
Zobel, J.

Title

Self-indexing inverted files for fast text retrieval

Source

ACM transactions on information systems. 14(1996) no.4, S.349-379

Year

1996

Abstract

Query processing costs on large text databases are dominated by the need to retrieve and scan the inverted list of each query term. Retrieval time for inverted lists can be greatly reduced by the use of compression, but this adds to the CPU time required. Shows that the CPU component of query response time for conjunctive Boolean queries and for informal ranked queries can be similarly reduced, at little cost in terms of storage, by the inclusion of an internal index in each compressed inverted list. This method has been applied in a retrieval system for a collection of nearly 2 million short documents. The self-indexing strategy adds less than 20% to the size of the compressed inverted file, which itself occupies less than 10% of the indexed text, yet can reduce processing time for Boolean queries of 5-10 terms to under one fifth of the previous cost. Similarly, ranked queries of 40-50 terms can be evaluated in as little as 25% of the previous time, with little or no loss of retrieval effectiveness

Similar documents (author)

1. Bell, T.C.; Moffat, A.; Nevill-Manning, C.G.; Witten, I.H.; Zobel, J.: Data compression in full-text retrieval system (1993) 3.38

   3.384441 = sum of:
     3.384441 = sum of:
       1.59773 = weight(author_txt:zobel in 5643) [ClassicSimilarity], result of:
         1.59773 = score(doc=5643,freq=1.0), product of:
           0.6802975 = queryWeight, product of:
             9.394302 = idf(docFreq=9, maxDocs=44218)
             0.07241597 = queryNorm
           2.3485756 = fieldWeight in 5643, product of:
             1.0 = tf(freq=1.0), with freq of:
               1.0 = termFreq=1.0
             9.394302 = idf(docFreq=9, maxDocs=44218)
             0.25 = fieldNorm(doc=5643)
       1.786711 = weight(author_txt:moffat in 5643) [ClassicSimilarity], result of:
         1.786711 = score(doc=5643,freq=1.0), product of:
           0.73293614 = queryWeight, product of:
             1.0379672 = boost
             9.7509775 = idf(docFreq=6, maxDocs=44218)
             0.07241597 = queryNorm
           2.4377444 = fieldWeight in 5643, product of:
             1.0 = tf(freq=1.0), with freq of:
               1.0 = termFreq=1.0
             9.7509775 = idf(docFreq=6, maxDocs=44218)
             0.25 = fieldNorm(doc=5643)
   

2. Moffat, A.; Bell, T.A.H.: In situ generation of compressed inverted files (1995) 1.79

   1.786711 = sum of:
     1.786711 = product of:
       3.573422 = sum of:
         3.573422 = weight(author_txt:moffat in 2648) [ClassicSimilarity], result of:
           3.573422 = score(doc=2648,freq=1.0), product of:
             0.73293614 = queryWeight, product of:
               1.0379672 = boost
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.07241597 = queryNorm
             4.8754888 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.5 = fieldNorm(doc=2648)
       0.5 = coord(1/2)
   

3. Wan, R.; Moffat, A.: Block merging for off-line compression (2007) 1.79

   1.786711 = sum of:
     1.786711 = product of:
       3.573422 = sum of:
         3.573422 = weight(author_txt:moffat in 81) [ClassicSimilarity], result of:
           3.573422 = score(doc=81,freq=1.0), product of:
             0.73293614 = queryWeight, product of:
               1.0379672 = boost
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.07241597 = queryNorm
             4.8754888 = fieldWeight in 81, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.5 = fieldNorm(doc=81)
       0.5 = coord(1/2)
   

4. Moffat, A.; Isal, R.Y.K.: Word-based text compression using the Burrows-Wheeler transform (2005) 1.79

   1.786711 = sum of:
     1.786711 = product of:
       3.573422 = sum of:
         3.573422 = weight(author_txt:moffat in 1044) [ClassicSimilarity], result of:
           3.573422 = score(doc=1044,freq=1.0), product of:
             0.73293614 = queryWeight, product of:
               1.0379672 = boost
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.07241597 = queryNorm
             4.8754888 = fieldWeight in 1044, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               9.7509775 = idf(docFreq=6, maxDocs=44218)
               0.5 = fieldNorm(doc=1044)
       0.5 = coord(1/2)
   

5. Kaszkiel, M.; Zobel, J.: Effective ranking with arbitrary passages (2001) 1.60

   1.59773 = sum of:
     1.59773 = product of:
       3.19546 = sum of:
         3.19546 = weight(author_txt:zobel in 5764) [ClassicSimilarity], result of:
           3.19546 = score(doc=5764,freq=1.0), product of:
             0.6802975 = queryWeight, product of:
               9.394302 = idf(docFreq=9, maxDocs=44218)
               0.07241597 = queryNorm
             4.697151 = fieldWeight in 5764, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               9.394302 = idf(docFreq=9, maxDocs=44218)
               0.5 = fieldNorm(doc=5764)
       0.5 = coord(1/2)
   

Similar documents (content)

1. Moffat, A.; Bell, T.A.H.: In situ generation of compressed inverted files (1995) 0.47

   0.4730935 = sum of:
     0.4730935 = product of:
       1.1827338 = sum of:
         0.022342563 = weight(abstract_txt:each in 2648) [ClassicSimilarity], result of:
           0.022342563 = score(doc=2648,freq=1.0), product of:
             0.069434986 = queryWeight, product of:
               1.0117846 = boost
               4.118742 = idf(docFreq=1954, maxDocs=44218)
               0.016661946 = queryNorm
             0.32177672 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.118742 = idf(docFreq=1954, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.026313791 = weight(abstract_txt:indexing in 2648) [ClassicSimilarity], result of:
           0.026313791 = score(doc=2648,freq=1.0), product of:
             0.07743643 = queryWeight, product of:
               1.0684927 = boost
               4.3495874 = idf(docFreq=1551, maxDocs=44218)
               0.016661946 = queryNorm
             0.3398115 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.3495874 = idf(docFreq=1551, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.06669628 = weight(abstract_txt:less in 2648) [ClassicSimilarity], result of:
           0.06669628 = score(doc=2648,freq=2.0), product of:
             0.114256464 = queryWeight, product of:
               1.2978941 = boost
               5.283428 = idf(docFreq=609, maxDocs=44218)
               0.016661946 = queryNorm
             0.58374184 = fieldWeight in 2648, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.283428 = idf(docFreq=609, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.049938235 = weight(abstract_txt:list in 2648) [ClassicSimilarity], result of:
           0.049938235 = score(doc=2648,freq=1.0), product of:
             0.11869848 = queryWeight, product of:
               1.322883 = boost
               5.3851523 = idf(docFreq=550, maxDocs=44218)
               0.016661946 = queryNorm
             0.42071503 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.3851523 = idf(docFreq=550, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.031719107 = weight(abstract_txt:text in 2648) [ClassicSimilarity], result of:
           0.031719107 = score(doc=2648,freq=1.0), product of:
             0.10040009 = queryWeight, product of:
               1.4900867 = boost
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.016661946 = queryNorm
             0.3159271 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.078074716 = weight(abstract_txt:boolean in 2648) [ClassicSimilarity], result of:
           0.078074716 = score(doc=2648,freq=1.0), product of:
             0.1598932 = queryWeight, product of:
               1.535373 = boost
               6.2501497 = idf(docFreq=231, maxDocs=44218)
               0.016661946 = queryNorm
             0.48829293 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.2501497 = idf(docFreq=231, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.08476821 = weight(abstract_txt:ranked in 2648) [ClassicSimilarity], result of:
           0.08476821 = score(doc=2648,freq=1.0), product of:
             0.16890599 = queryWeight, product of:
               1.5780523 = boost
               6.4238877 = idf(docFreq=194, maxDocs=44218)
               0.016661946 = queryNorm
             0.5018662 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.4238877 = idf(docFreq=194, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.22728011 = weight(abstract_txt:compressed in 2648) [ClassicSimilarity], result of:
           0.22728011 = score(doc=2648,freq=1.0), product of:
             0.32598478 = queryWeight, product of:
               2.1922877 = boost
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.016661946 = queryNorm
             0.6972108 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.085164994 = weight(abstract_txt:queries in 2648) [ClassicSimilarity], result of:
           0.085164994 = score(doc=2648,freq=1.0), product of:
             0.21347177 = queryWeight, product of:
               2.5089042 = boost
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.016661946 = queryNorm
             0.39895204 = fieldWeight in 2648, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
         0.5104358 = weight(abstract_txt:inverted in 2648) [ClassicSimilarity], result of:
           0.5104358 = score(doc=2648,freq=2.0), product of:
             0.6022181 = queryWeight, product of:
               4.7113543 = boost
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.016661946 = queryNorm
             0.84759295 = fieldWeight in 2648, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.078125 = fieldNorm(doc=2648)
       0.4 = coord(10/25)
   

2. Persin, M.; Zobel, J.; Sacks-Davis, R.: Filtered document retrieval with frequency-sorted indexes (1996) 0.38

   0.37734175 = sum of:
     0.37734175 = product of:
       1.3476491 = sum of:
         0.10172185 = weight(abstract_txt:ranked in 6758) [ClassicSimilarity], result of:
           0.10172185 = score(doc=6758,freq=1.0), product of:
             0.16890599 = queryWeight, product of:
               1.5780523 = boost
               6.4238877 = idf(docFreq=194, maxDocs=44218)
               0.016661946 = queryNorm
             0.6022395 = fieldWeight in 6758, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.4238877 = idf(docFreq=194, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.03220825 = weight(abstract_txt:retrieval in 6758) [ClassicSimilarity], result of:
           0.03220825 = score(doc=6758,freq=1.0), product of:
             0.09886069 = queryWeight, product of:
               1.7073623 = boost
               3.4751394 = idf(docFreq=3720, maxDocs=44218)
               0.016661946 = queryNorm
             0.3257943 = fieldWeight in 6758, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               3.4751394 = idf(docFreq=3720, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.12941274 = weight(abstract_txt:reduced in 6758) [ClassicSimilarity], result of:
           0.12941274 = score(doc=6758,freq=1.0), product of:
             0.19831409 = queryWeight, product of:
               1.7099195 = boost
               6.9606886 = idf(docFreq=113, maxDocs=44218)
               0.016661946 = queryNorm
             0.6525645 = fieldWeight in 6758, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.9606886 = idf(docFreq=113, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.27273613 = weight(abstract_txt:compressed in 6758) [ClassicSimilarity], result of:
           0.27273613 = score(doc=6758,freq=1.0), product of:
             0.32598478 = queryWeight, product of:
               2.1922877 = boost
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.016661946 = queryNorm
             0.836653 = fieldWeight in 6758, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.10219799 = weight(abstract_txt:queries in 6758) [ClassicSimilarity], result of:
           0.10219799 = score(doc=6758,freq=1.0), product of:
             0.21347177 = queryWeight, product of:
               2.5089042 = boost
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.016661946 = queryNorm
             0.47874242 = fieldWeight in 6758, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.09684913 = weight(abstract_txt:time in 6758) [ClassicSimilarity], result of:
           0.09684913 = score(doc=6758,freq=2.0), product of:
             0.17609054 = queryWeight, product of:
               2.5476332 = boost
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.016661946 = queryNorm
             0.5499962 = fieldWeight in 6758, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
         0.61252296 = weight(abstract_txt:inverted in 6758) [ClassicSimilarity], result of:
           0.61252296 = score(doc=6758,freq=2.0), product of:
             0.6022181 = queryWeight, product of:
               4.7113543 = boost
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.016661946 = queryNorm
             1.0171115 = fieldWeight in 6758, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.09375 = fieldNorm(doc=6758)
       0.28 = coord(7/25)
   

3. Carterette, B.; Can, F.: Comparing inverted files and signature files for searching a large lexicon (2005) 0.31

   0.3068494 = sum of:
     0.3068494 = product of:
       1.0958906 = sum of:
         0.022342563 = weight(abstract_txt:each in 1029) [ClassicSimilarity], result of:
           0.022342563 = score(doc=1029,freq=1.0), product of:
             0.069434986 = queryWeight, product of:
               1.0117846 = boost
               4.118742 = idf(docFreq=1954, maxDocs=44218)
               0.016661946 = queryNorm
             0.32177672 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.118742 = idf(docFreq=1954, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.047161393 = weight(abstract_txt:less in 1029) [ClassicSimilarity], result of:
           0.047161393 = score(doc=1029,freq=1.0), product of:
             0.114256464 = queryWeight, product of:
               1.2978941 = boost
               5.283428 = idf(docFreq=609, maxDocs=44218)
               0.016661946 = queryNorm
             0.41276783 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.283428 = idf(docFreq=609, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.031719107 = weight(abstract_txt:terms in 1029) [ClassicSimilarity], result of:
           0.031719107 = score(doc=1029,freq=1.0), product of:
             0.10040009 = queryWeight, product of:
               1.4900867 = boost
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.016661946 = queryNorm
             0.3159271 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.22728011 = weight(abstract_txt:compressed in 1029) [ClassicSimilarity], result of:
           0.22728011 = score(doc=1029,freq=1.0), product of:
             0.32598478 = queryWeight, product of:
               2.1922877 = boost
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.016661946 = queryNorm
             0.6972108 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               8.924298 = idf(docFreq=15, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.085164994 = weight(abstract_txt:queries in 1029) [ClassicSimilarity], result of:
           0.085164994 = score(doc=1029,freq=1.0), product of:
             0.21347177 = queryWeight, product of:
               2.5089042 = boost
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.016661946 = queryNorm
             0.39895204 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.057068896 = weight(abstract_txt:time in 1029) [ClassicSimilarity], result of:
           0.057068896 = score(doc=1029,freq=1.0), product of:
             0.17609054 = queryWeight, product of:
               2.5476332 = boost
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.016661946 = queryNorm
             0.32408836 = fieldWeight in 1029, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
         0.6251536 = weight(abstract_txt:inverted in 1029) [ClassicSimilarity], result of:
           0.6251536 = score(doc=1029,freq=3.0), product of:
             0.6022181 = queryWeight, product of:
               4.7113543 = boost
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.016661946 = queryNorm
             1.0380851 = fieldWeight in 1029, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.078125 = fieldNorm(doc=1029)
       0.28 = coord(7/25)
   

4. Cheng, C.-S.; Chung, C.-P.; Shann, J.J.-J.: Fast query evaluation through document identifier assignment for inverted file-based information retrieval systems (2006) 0.25

   0.2468971 = sum of:
     0.2468971 = product of:
       0.77155346 = sum of:
         0.05315191 = weight(abstract_txt:processing in 979) [ClassicSimilarity], result of:
           0.05315191 = score(doc=979,freq=3.0), product of:
             0.09955625 = queryWeight, product of:
               1.2115271 = boost
               4.931848 = idf(docFreq=866, maxDocs=44218)
               0.016661946 = queryNorm
             0.5338882 = fieldWeight in 979, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               4.931848 = idf(docFreq=866, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.05674087 = weight(abstract_txt:terms in 979) [ClassicSimilarity], result of:
           0.05674087 = score(doc=979,freq=5.0), product of:
             0.10040009 = queryWeight, product of:
               1.4900867 = boost
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.016661946 = queryNorm
             0.5651476 = fieldWeight in 979, product of:
               2.236068 = tf(freq=5.0), with freq of:
                 5.0 = termFreq=5.0
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.030366227 = weight(abstract_txt:retrieval in 979) [ClassicSimilarity], result of:
           0.030366227 = score(doc=979,freq=2.0), product of:
             0.09886069 = queryWeight, product of:
               1.7073623 = boost
               3.4751394 = idf(docFreq=3720, maxDocs=44218)
               0.016661946 = queryNorm
             0.3071618 = fieldWeight in 979, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.4751394 = idf(docFreq=3720, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.08627516 = weight(abstract_txt:reduced in 979) [ClassicSimilarity], result of:
           0.08627516 = score(doc=979,freq=1.0), product of:
             0.19831409 = queryWeight, product of:
               1.7099195 = boost
               6.9606886 = idf(docFreq=113, maxDocs=44218)
               0.016661946 = queryNorm
             0.43504304 = fieldWeight in 979, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               6.9606886 = idf(docFreq=113, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.10906426 = weight(abstract_txt:query in 979) [ClassicSimilarity], result of:
           0.10906426 = score(doc=979,freq=7.0), product of:
             0.13874449 = queryWeight, product of:
               1.7516704 = boost
               4.7537646 = idf(docFreq=1035, maxDocs=44218)
               0.016661946 = queryNorm
             0.78607994 = fieldWeight in 979, product of:
               2.6457512 = tf(freq=7.0), with freq of:
                 7.0 = termFreq=7.0
               4.7537646 = idf(docFreq=1035, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.068132 = weight(abstract_txt:queries in 979) [ClassicSimilarity], result of:
           0.068132 = score(doc=979,freq=1.0), product of:
             0.21347177 = queryWeight, product of:
               2.5089042 = boost
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.016661946 = queryNorm
             0.31916162 = fieldWeight in 979, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.079076976 = weight(abstract_txt:time in 979) [ClassicSimilarity], result of:
           0.079076976 = score(doc=979,freq=3.0), product of:
             0.17609054 = queryWeight, product of:
               2.5476332 = boost
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.016661946 = queryNorm
             0.44907 = fieldWeight in 979, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
         0.2887461 = weight(abstract_txt:inverted in 979) [ClassicSimilarity], result of:
           0.2887461 = score(doc=979,freq=1.0), product of:
             0.6022181 = queryWeight, product of:
               4.7113543 = boost
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.016661946 = queryNorm
             0.47947097 = fieldWeight in 979, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.0625 = fieldNorm(doc=979)
       0.32 = coord(8/25)
   

5. Chang, M.; Poon, C.K.: Efficient phrase querying with common phrase index (2008) 0.24

   0.23749913 = sum of:
     0.23749913 = product of:
       0.84821117 = sum of:
         0.045846365 = weight(abstract_txt:previous in 2061) [ClassicSimilarity], result of:
           0.045846365 = score(doc=2061,freq=1.0), product of:
             0.11212255 = queryWeight, product of:
               1.2857169 = boost
               5.2338576 = idf(docFreq=640, maxDocs=44218)
               0.016661946 = queryNorm
             0.40889513 = fieldWeight in 2061, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.2338576 = idf(docFreq=640, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.085803814 = weight(abstract_txt:cost in 2061) [ClassicSimilarity], result of:
           0.085803814 = score(doc=2061,freq=2.0), product of:
             0.13515043 = queryWeight, product of:
               1.4115868 = boost
               5.746245 = idf(docFreq=383, maxDocs=44218)
               0.016661946 = queryNorm
             0.6348764 = fieldWeight in 2061, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.746245 = idf(docFreq=383, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.031719107 = weight(abstract_txt:text in 2061) [ClassicSimilarity], result of:
           0.031719107 = score(doc=2061,freq=1.0), product of:
             0.10040009 = queryWeight, product of:
               1.4900867 = boost
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.016661946 = queryNorm
             0.3159271 = fieldWeight in 2061, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.0438666 = idf(docFreq=2106, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.072871625 = weight(abstract_txt:query in 2061) [ClassicSimilarity], result of:
           0.072871625 = score(doc=2061,freq=2.0), product of:
             0.13874449 = queryWeight, product of:
               1.7516704 = boost
               4.7537646 = idf(docFreq=1035, maxDocs=44218)
               0.016661946 = queryNorm
             0.52522177 = fieldWeight in 2061, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.7537646 = idf(docFreq=1035, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.17032999 = weight(abstract_txt:queries in 2061) [ClassicSimilarity], result of:
           0.17032999 = score(doc=2061,freq=4.0), product of:
             0.21347177 = queryWeight, product of:
               2.5089042 = boost
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.016661946 = queryNorm
             0.7979041 = fieldWeight in 2061, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               5.106586 = idf(docFreq=727, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.08070761 = weight(abstract_txt:time in 2061) [ClassicSimilarity], result of:
           0.08070761 = score(doc=2061,freq=2.0), product of:
             0.17609054 = queryWeight, product of:
               2.5476332 = boost
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.016661946 = queryNorm
             0.45833018 = fieldWeight in 2061, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.148331 = idf(docFreq=1897, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
         0.36093262 = weight(abstract_txt:inverted in 2061) [ClassicSimilarity], result of:
           0.36093262 = score(doc=2061,freq=1.0), product of:
             0.6022181 = queryWeight, product of:
               4.7113543 = boost
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.016661946 = queryNorm
             0.5993387 = fieldWeight in 2061, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.6715355 = idf(docFreq=55, maxDocs=44218)
               0.078125 = fieldNorm(doc=2061)
       0.28 = coord(7/25)