Document (#33044)

Author

Cacheda, F.
Plachouras, V.
Ounis, l.

Title

¬A case study of distributed information retrieval architectures to index one terabyte of text

Source

Information processing and management. 41(2005) no.5, S.1141-1162

Year

2005

Abstract

The increasing number of documents to be indexed in many environments (Web, intranets, digital libraries) and the limitations of a single centralised index (lack of scalability, server overloading and failures), lead to the use of distributed information retrieval systems to efficiently search and locate the desired information. This work is a case study of different architectures for a distributed information retrieval system, in order to provide a guide to approximate the optimal architecture with a specific set of resources. We analyse the effectiveness of a distributed, replicated and clustered architecture simulating a variable number of workstations (from 1 up to 4096). A collection of approximately 94 million documents and 1 terabyte (TB) of text is used to test the performance of the different architectures. In a purely distributed information retrieval system, the brokers become the bottleneck due to the high number of local answer sets to be sorted. In a replicated system, the network is the bottleneck due to the high number of query servers and the continuous data interchange with the brokers. Finally, we demonstrate that a clustered system will outperform a replicated system if a high number of query servers is used, essentially due to the reduction of the network load. However a change in the distribution of the users' queries could reduce the performance of a clustered system.

Similar documents (author)

1. He, B.; Ounis, I.: Combining fields for query expansion and adaptive query expansion (2007) 4.86

   4.85849 = sum of:
     4.85849 = weight(author_txt:ounis in 2927) [ClassicSimilarity], result of:
       4.85849 = fieldWeight in 2927, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         9.71698 = idf(docFreq=6, maxDocs=42740)
         0.5 = fieldNorm(doc=2927)
   

2. Lioma, C.; Ounis, I.: ¬A syntactically-based query reformulation technique for information retrieval (2008) 4.86

   4.85849 = sum of:
     4.85849 = weight(author_txt:ounis in 4032) [ClassicSimilarity], result of:
       4.85849 = fieldWeight in 4032, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         9.71698 = idf(docFreq=6, maxDocs=42740)
         0.5 = fieldNorm(doc=4032)
   

3. Chang, Y.; Ounis, I.; Kim, M.: Query reformulation using automatically generated query concepts from a document space (2006) 3.64

   3.6438675 = sum of:
     3.6438675 = weight(author_txt:ounis in 2973) [ClassicSimilarity], result of:
       3.6438675 = fieldWeight in 2973, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         9.71698 = idf(docFreq=6, maxDocs=42740)
         0.375 = fieldNorm(doc=2973)
   

4. Cacheda, F.; Carneiro, V.; Plachouras, V.; Ounis, I.: Performance analysis of distributed information retrieval architectures using an improved network simulation model (2007) 3.04

   3.0365562 = sum of:
     3.0365562 = weight(author_txt:ounis in 2904) [ClassicSimilarity], result of:
       3.0365562 = fieldWeight in 2904, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         9.71698 = idf(docFreq=6, maxDocs=42740)
         0.3125 = fieldNorm(doc=2904)
   

5. Gray, A.J.G.; Gray, N.; Hall, C.W.; Ounis, I.: Finding the right term : retrieving and exploring semantic concepts in astronomical vocabularies (2010) 3.04

   3.0365562 = sum of:
     3.0365562 = weight(author_txt:ounis in 1236) [ClassicSimilarity], result of:
       3.0365562 = fieldWeight in 1236, product of:
         1.0 = tf(freq=1.0), with freq of:
           1.0 = termFreq=1.0
         9.71698 = idf(docFreq=6, maxDocs=42740)
         0.3125 = fieldNorm(doc=1236)
   

Similar documents (content)

1. Cacheda, F.; Carneiro, V.; Plachouras, V.; Ounis, I.: Performance analysis of distributed information retrieval architectures using an improved network simulation model (2007) 0.46

   0.45900097 = sum of:
     0.45900097 = product of:
       1.043184 = sum of:
         0.015359997 = weight(abstract_txt:documents in 2904) [ClassicSimilarity], result of:
           0.015359997 = score(doc=2904,freq=1.0), product of:
             0.05971731 = queryWeight, product of:
               1.0161306 = boost
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.014280383 = queryNorm
             0.2572118 = fieldWeight in 2904, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.07438775 = weight(abstract_txt:centralised in 2904) [ClassicSimilarity], result of:
           0.07438775 = score(doc=2904,freq=1.0), product of:
             0.13567415 = queryWeight, product of:
               1.0830112 = boost
               8.772519 = idf(docFreq=17, maxDocs=42740)
               0.014280383 = queryNorm
             0.54828244 = fieldWeight in 2904, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               8.772519 = idf(docFreq=17, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.049340796 = weight(abstract_txt:network in 2904) [ClassicSimilarity], result of:
           0.049340796 = score(doc=2904,freq=5.0), product of:
             0.07603034 = queryWeight, product of:
               1.1465496 = boost
               4.643594 = idf(docFreq=1117, maxDocs=42740)
               0.014280383 = queryNorm
             0.64896196 = fieldWeight in 2904, product of:
               2.236068 = tf(freq=5.0), with freq of:
                 5.0 = termFreq=5.0
               4.643594 = idf(docFreq=1117, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.023399679 = weight(abstract_txt:index in 2904) [ClassicSimilarity], result of:
           0.023399679 = score(doc=2904,freq=1.0), product of:
             0.079064116 = queryWeight, product of:
               1.1692008 = boost
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.014280383 = queryNorm
             0.29595828 = fieldWeight in 2904, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.013694107 = weight(abstract_txt:information in 2904) [ClassicSimilarity], result of:
           0.013694107 = score(doc=2904,freq=3.0), product of:
             0.05205569 = queryWeight, product of:
               1.5000423 = boost
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.014280383 = queryNorm
             0.26306647 = fieldWeight in 2904, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.025926176 = weight(abstract_txt:retrieval in 2904) [ClassicSimilarity], result of:
           0.025926176 = score(doc=2904,freq=2.0), product of:
             0.08465744 = queryWeight, product of:
               1.7109879 = boost
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.014280383 = queryNorm
             0.30624807 = fieldWeight in 2904, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.27430835 = weight(abstract_txt:brokers in 2904) [ClassicSimilarity], result of:
           0.27430835 = score(doc=2904,freq=2.0), product of:
             0.3238338 = queryWeight, product of:
               2.366249 = boost
               9.583449 = idf(docFreq=7, maxDocs=42740)
               0.014280383 = queryNorm
             0.8470652 = fieldWeight in 2904, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               9.583449 = idf(docFreq=7, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.056244906 = weight(abstract_txt:system in 2904) [ClassicSimilarity], result of:
           0.056244906 = score(doc=2904,freq=5.0), product of:
             0.119659 = queryWeight, product of:
               2.4913383 = boost
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.014280383 = queryNorm
             0.47004327 = fieldWeight in 2904, product of:
               2.236068 = tf(freq=5.0), with freq of:
                 5.0 = termFreq=5.0
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.0386976 = weight(abstract_txt:number in 2904) [ClassicSimilarity], result of:
           0.0386976 = score(doc=2904,freq=1.0), product of:
             0.15006365 = queryWeight, product of:
               2.5468721 = boost
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.014280383 = queryNorm
             0.25787458 = fieldWeight in 2904, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.23736864 = weight(abstract_txt:replicated in 2904) [ClassicSimilarity], result of:
           0.23736864 = score(doc=2904,freq=1.0), product of:
             0.4241168 = queryWeight, product of:
               3.316559 = boost
               8.954841 = idf(docFreq=14, maxDocs=42740)
               0.014280383 = queryNorm
             0.55967754 = fieldWeight in 2904, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               8.954841 = idf(docFreq=14, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
         0.234456 = weight(abstract_txt:distributed in 2904) [ClassicSimilarity], result of:
           0.234456 = score(doc=2904,freq=5.0), product of:
             0.29165563 = queryWeight, product of:
               3.5506232 = boost
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.014280383 = queryNorm
             0.80387956 = fieldWeight in 2904, product of:
               2.236068 = tf(freq=5.0), with freq of:
                 5.0 = termFreq=5.0
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.0625 = fieldNorm(doc=2904)
       0.44 = coord(11/25)
   

2. Town, C.; Harrison, K.: Large-scale grid computing for content-based image retrieval (2010) 0.17

   0.17248894 = sum of:
     0.17248894 = product of:
       0.43122235 = sum of:
         0.012810045 = weight(abstract_txt:text in 948) [ClassicSimilarity], result of:
           0.012810045 = score(doc=948,freq=1.0), product of:
             0.057836395 = queryWeight, product of:
               4.0500593 = idf(docFreq=2023, maxDocs=42740)
               0.014280383 = queryNorm
             0.22148761 = fieldWeight in 948, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.0500593 = idf(docFreq=2023, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.027289357 = weight(abstract_txt:performance in 948) [ClassicSimilarity], result of:
           0.027289357 = score(doc=948,freq=2.0), product of:
             0.07600106 = queryWeight, product of:
               1.1463288 = boost
               4.6426997 = idf(docFreq=1118, maxDocs=42740)
               0.014280383 = queryNorm
             0.35906547 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.6426997 = idf(docFreq=1118, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.02047472 = weight(abstract_txt:index in 948) [ClassicSimilarity], result of:
           0.02047472 = score(doc=948,freq=1.0), product of:
             0.079064116 = queryWeight, product of:
               1.1692008 = boost
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.014280383 = queryNorm
             0.2589635 = fieldWeight in 948, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.021754632 = weight(abstract_txt:case in 948) [ClassicSimilarity], result of:
           0.021754632 = score(doc=948,freq=1.0), product of:
             0.08232567 = queryWeight, product of:
               1.193073 = boost
               4.8320165 = idf(docFreq=925, maxDocs=42740)
               0.014280383 = queryNorm
             0.2642509 = fieldWeight in 948, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.8320165 = idf(docFreq=925, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.022685403 = weight(abstract_txt:retrieval in 948) [ClassicSimilarity], result of:
           0.022685403 = score(doc=948,freq=2.0), product of:
             0.08465744 = queryWeight, product of:
               1.7109879 = boost
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.014280383 = queryNorm
             0.26796705 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.070220225 = weight(abstract_txt:servers in 948) [ClassicSimilarity], result of:
           0.070220225 = score(doc=948,freq=1.0), product of:
             0.17980796 = queryWeight, product of:
               1.7632092 = boost
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.014280383 = queryNorm
             0.390529 = fieldWeight in 948, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.047228664 = weight(abstract_txt:high in 948) [ClassicSimilarity], result of:
           0.047228664 = score(doc=948,freq=2.0), product of:
             0.12540792 = queryWeight, product of:
               1.803464 = boost
               4.8694243 = idf(docFreq=891, maxDocs=42740)
               0.014280383 = queryNorm
             0.37660033 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.8694243 = idf(docFreq=891, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.031125853 = weight(abstract_txt:system in 948) [ClassicSimilarity], result of:
           0.031125853 = score(doc=948,freq=2.0), product of:
             0.119659 = queryWeight, product of:
               2.4913383 = boost
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.014280383 = queryNorm
             0.2601213 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.04788583 = weight(abstract_txt:number in 948) [ClassicSimilarity], result of:
           0.04788583 = score(doc=948,freq=2.0), product of:
             0.15006365 = queryWeight, product of:
               2.5468721 = boost
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.014280383 = queryNorm
             0.31910348 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
         0.12974763 = weight(abstract_txt:distributed in 948) [ClassicSimilarity], result of:
           0.12974763 = score(doc=948,freq=2.0), product of:
             0.29165563 = queryWeight, product of:
               3.5506232 = boost
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.014280383 = queryNorm
             0.44486582 = fieldWeight in 948, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.0546875 = fieldNorm(doc=948)
       0.4 = coord(10/25)
   

3. Meldelzon, A.O.; Mihaila, G.A.; Milo, T.: Querying the World Wide Web (1997) 0.16

   0.1641852 = sum of:
     0.1641852 = product of:
       0.51307875 = sum of:
         0.027152894 = weight(abstract_txt:documents in 930) [ClassicSimilarity], result of:
           0.027152894 = score(doc=930,freq=2.0), product of:
             0.05971731 = queryWeight, product of:
               1.0161306 = boost
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.014280383 = queryNorm
             0.45469052 = fieldWeight in 930, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.039007325 = weight(abstract_txt:network in 930) [ClassicSimilarity], result of:
           0.039007325 = score(doc=930,freq=2.0), product of:
             0.07603034 = queryWeight, product of:
               1.1465496 = boost
               4.643594 = idf(docFreq=1117, maxDocs=42740)
               0.014280383 = queryNorm
             0.5130495 = fieldWeight in 930, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.643594 = idf(docFreq=1117, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.041313864 = weight(abstract_txt:query in 930) [ClassicSimilarity], result of:
           0.041313864 = score(doc=930,freq=2.0), product of:
             0.078998715 = queryWeight, product of:
               1.1687171 = boost
               4.7333736 = idf(docFreq=1021, maxDocs=42740)
               0.014280383 = queryNorm
             0.5229688 = fieldWeight in 930, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.7333736 = idf(docFreq=1021, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.0584992 = weight(abstract_txt:index in 930) [ClassicSimilarity], result of:
           0.0584992 = score(doc=930,freq=4.0), product of:
             0.079064116 = queryWeight, product of:
               1.1692008 = boost
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.014280383 = queryNorm
             0.7398957 = fieldWeight in 930, product of:
               2.0 = tf(freq=4.0), with freq of:
                 4.0 = termFreq=4.0
               4.7353325 = idf(docFreq=1019, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.009882871 = weight(abstract_txt:information in 930) [ClassicSimilarity], result of:
           0.009882871 = score(doc=930,freq=1.0), product of:
             0.05205569 = queryWeight, product of:
               1.5000423 = boost
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.014280383 = queryNorm
             0.18985188 = fieldWeight in 930, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.03240772 = weight(abstract_txt:retrieval in 930) [ClassicSimilarity], result of:
           0.03240772 = score(doc=930,freq=2.0), product of:
             0.08465744 = queryWeight, product of:
               1.7109879 = boost
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.014280383 = queryNorm
             0.3828101 = fieldWeight in 930, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.17374998 = weight(abstract_txt:servers in 930) [ClassicSimilarity], result of:
           0.17374998 = score(doc=930,freq=3.0), product of:
             0.17980796 = queryWeight, product of:
               1.7632092 = boost
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.014280383 = queryNorm
             0.96630865 = fieldWeight in 930, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
         0.13106489 = weight(abstract_txt:distributed in 930) [ClassicSimilarity], result of:
           0.13106489 = score(doc=930,freq=1.0), product of:
             0.29165563 = queryWeight, product of:
               3.5506232 = boost
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.014280383 = queryNorm
             0.44938233 = fieldWeight in 930, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.078125 = fieldNorm(doc=930)
       0.32 = coord(8/25)
   

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) 0.16

   0.15690586 = sum of:
     0.15690586 = product of:
       0.4358496 = sum of:
         0.021722317 = weight(abstract_txt:documents in 2980) [ClassicSimilarity], result of:
           0.021722317 = score(doc=2980,freq=2.0), product of:
             0.05971731 = queryWeight, product of:
               1.0161306 = boost
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.014280383 = queryNorm
             0.36375242 = fieldWeight in 2980, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.115389 = idf(docFreq=1895, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.038197145 = weight(abstract_txt:performance in 2980) [ClassicSimilarity], result of:
           0.038197145 = score(doc=2980,freq=3.0), product of:
             0.07600106 = queryWeight, product of:
               1.1463288 = boost
               4.6426997 = idf(docFreq=1118, maxDocs=42740)
               0.014280383 = queryNorm
             0.50258696 = fieldWeight in 2980, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               4.6426997 = idf(docFreq=1118, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.06183293 = weight(abstract_txt:query in 2980) [ClassicSimilarity], result of:
           0.06183293 = score(doc=2980,freq=7.0), product of:
             0.078998715 = queryWeight, product of:
               1.1687171 = boost
               4.7333736 = idf(docFreq=1021, maxDocs=42740)
               0.014280383 = queryNorm
             0.78270805 = fieldWeight in 2980, product of:
               2.6457512 = tf(freq=7.0), with freq of:
                 7.0 = termFreq=7.0
               4.7333736 = idf(docFreq=1021, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.011181192 = weight(abstract_txt:information in 2980) [ClassicSimilarity], result of:
           0.011181192 = score(doc=2980,freq=2.0), product of:
             0.05205569 = queryWeight, product of:
               1.5000423 = boost
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.014280383 = queryNorm
             0.21479288 = fieldWeight in 2980, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.025926176 = weight(abstract_txt:retrieval in 2980) [ClassicSimilarity], result of:
           0.025926176 = score(doc=2980,freq=2.0), product of:
             0.08465744 = queryWeight, product of:
               1.7109879 = boost
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.014280383 = queryNorm
             0.30624807 = fieldWeight in 2980, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               3.4648013 = idf(docFreq=3633, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.038166523 = weight(abstract_txt:high in 2980) [ClassicSimilarity], result of:
           0.038166523 = score(doc=2980,freq=1.0), product of:
             0.12540792 = queryWeight, product of:
               1.803464 = boost
               4.8694243 = idf(docFreq=891, maxDocs=42740)
               0.014280383 = queryNorm
             0.30433902 = fieldWeight in 2980, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.8694243 = idf(docFreq=891, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.025153488 = weight(abstract_txt:system in 2980) [ClassicSimilarity], result of:
           0.025153488 = score(doc=2980,freq=1.0), product of:
             0.119659 = queryWeight, product of:
               2.4913383 = boost
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.014280383 = queryNorm
             0.21020974 = fieldWeight in 2980, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               3.3633559 = idf(docFreq=4021, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.054726668 = weight(abstract_txt:number in 2980) [ClassicSimilarity], result of:
           0.054726668 = score(doc=2980,freq=2.0), product of:
             0.15006365 = queryWeight, product of:
               2.5468721 = boost
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.014280383 = queryNorm
             0.3646897 = fieldWeight in 2980, product of:
               1.4142135 = tf(freq=2.0), with freq of:
                 2.0 = termFreq=2.0
               4.1259933 = idf(docFreq=1875, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
         0.15894316 = weight(abstract_txt:clustered in 2980) [ClassicSimilarity], result of:
           0.15894316 = score(doc=2980,freq=1.0), product of:
             0.3246119 = queryWeight, product of:
               2.9015312 = boost
               7.834249 = idf(docFreq=45, maxDocs=42740)
               0.014280383 = queryNorm
             0.48964056 = fieldWeight in 2980, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.834249 = idf(docFreq=45, maxDocs=42740)
               0.0625 = fieldNorm(doc=2980)
       0.36 = coord(9/25)
   

5. Miller, R.S.: Textual databases : an object-based model (1993) 0.14

   0.1412465 = sum of:
     0.1412465 = product of:
       0.7062325 = sum of:
         0.029280104 = weight(abstract_txt:text in 626) [ClassicSimilarity], result of:
           0.029280104 = score(doc=626,freq=1.0), product of:
             0.057836395 = queryWeight, product of:
               4.0500593 = idf(docFreq=2023, maxDocs=42740)
               0.014280383 = queryNorm
             0.5062574 = fieldWeight in 626, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               4.0500593 = idf(docFreq=2023, maxDocs=42740)
               0.125 = fieldNorm(doc=626)
         0.027388213 = weight(abstract_txt:information in 626) [ClassicSimilarity], result of:
           0.027388213 = score(doc=626,freq=3.0), product of:
             0.05205569 = queryWeight, product of:
               1.5000423 = boost
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.014280383 = queryNorm
             0.52613294 = fieldWeight in 626, product of:
               1.7320508 = tf(freq=3.0), with freq of:
                 3.0 = termFreq=3.0
               2.430104 = idf(docFreq=10226, maxDocs=42740)
               0.125 = fieldNorm(doc=626)
         0.16050337 = weight(abstract_txt:servers in 626) [ClassicSimilarity], result of:
           0.16050337 = score(doc=626,freq=1.0), product of:
             0.17980796 = queryWeight, product of:
               1.7632092 = boost
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.014280383 = queryNorm
             0.8926377 = fieldWeight in 626, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.141102 = idf(docFreq=91, maxDocs=42740)
               0.125 = fieldNorm(doc=626)
         0.27935696 = weight(abstract_txt:architectures in 626) [ClassicSimilarity], result of:
           0.27935696 = score(doc=626,freq=1.0), product of:
             0.2978216 = queryWeight, product of:
               2.7792213 = boost
               7.5040073 = idf(docFreq=63, maxDocs=42740)
               0.014280383 = queryNorm
             0.9380009 = fieldWeight in 626, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               7.5040073 = idf(docFreq=63, maxDocs=42740)
               0.125 = fieldNorm(doc=626)
         0.20970382 = weight(abstract_txt:distributed in 626) [ClassicSimilarity], result of:
           0.20970382 = score(doc=626,freq=1.0), product of:
             0.29165563 = queryWeight, product of:
               3.5506232 = boost
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.014280383 = queryNorm
             0.7190117 = fieldWeight in 626, product of:
               1.0 = tf(freq=1.0), with freq of:
                 1.0 = termFreq=1.0
               5.752094 = idf(docFreq=368, maxDocs=42740)
               0.125 = fieldNorm(doc=626)
       0.2 = coord(5/25)