Document (#42035)

Author
Li, X.
Schijvenaars, B.J.A.
Rijke, M.de
Title
Investigating queries and search failures in academic search
Source
Information processing and management. 53(2017) no.3, S.666-683
Year
2017
Abstract
Academic search concerns the retrieval and profiling of information objects in the domain of academic research. In this paper we reveal important observations of academic search queries, and provide an algorithmic solution to address a type of failure during search sessions: null queries. We start by providing a general characterization of academic search queries, by analyzing a large-scale transaction log of a leading academic search engine. Unlike previous small-scale analyses of academic search queries, we find important differences with query characteristics known from web search. E.g., in academic search there is a substantially bigger proportion of entity queries, and a heavier tail in query length distribution. We then focus on search failures and, in particular, on null queries that lead to an empty search engine result page, on null sessions that contain such null queries, and on users who are prone to issue null queries. In academic search approximately 1 in 10 queries is a null query, and 25% of the sessions contain a null query. They appear in different types of search sessions, and prevent users from achieving their search goal. To address the high rate of null queries in academic search, we consider the task of providing query suggestions. Specifically we focus on a highly frequent query type: non-boolean informational queries. To this end we need to overcome query sparsity and make effective use of session information. We find that using entities helps to surface more relevant query suggestions in the face of query sparsity. We also find that query suggestions should be conditioned on the type of session in which they are offered to be more effective. After casting the session classification problem as a multi-label classification problem, we generate session-conditional query suggestions based on predicted session type. We find that this session-conditional method leads to significant improvements over a generic query suggestion method. Personalization yields very little further improvements over session-conditional query suggestions.
Content
Vgl.: http://www.sciencedirect.com/science/article/pii/S0306457316304071.

Similar documents (author)

  1. De Rijke, M. -> Rijke, M. de: 4.60
    4.5964546 = sum of:
      4.5964546 = weight(author_txt:rijke in 117) [ClassicSimilarity], result of:
        4.5964546 = fieldWeight in 117, product of:
          1.4142135 = tf(freq=2.0), with freq of:
            2.0 = termFreq=2.0
          8.667158 = idf(docFreq=19, maxDocs=42740)
          0.375 = fieldNorm(doc=117)
    
  2. Li, X.; Rijke, M.de: Characterizing and predicting downloads in academic search (2019) 4.33
    4.333579 = sum of:
      4.333579 = weight(author_txt:rijke in 1104) [ClassicSimilarity], result of:
        4.333579 = fieldWeight in 1104, product of:
          1.0 = tf(freq=1.0), with freq of:
            1.0 = termFreq=1.0
          8.667158 = idf(docFreq=19, maxDocs=42740)
          0.5 = fieldNorm(doc=1104)
    
  3. DeRijke, M. -> Rijke, M. de: 3.79
    3.7918816 = sum of:
      3.7918816 = weight(author_txt:rijke in 117) [ClassicSimilarity], result of:
        3.7918816 = fieldWeight in 117, product of:
          1.0 = tf(freq=1.0), with freq of:
            1.0 = termFreq=1.0
          8.667158 = idf(docFreq=19, maxDocs=42740)
          0.4375 = fieldNorm(doc=117)
    
  4. Meij, E.; Rijke, M. de: Thesaurus-based feedback to support mixed search and browsing environments (2007) 3.79
    3.7918816 = sum of:
      3.7918816 = weight(author_txt:rijke in 4433) [ClassicSimilarity], result of:
        3.7918816 = fieldWeight in 4433, product of:
          1.0 = tf(freq=1.0), with freq of:
            1.0 = termFreq=1.0
          8.667158 = idf(docFreq=19, maxDocs=42740)
          0.4375 = fieldNorm(doc=4433)
    
  5. Cai, F.; Rijke, M. de: Learning from homologous queries and semantically related terms for query auto completion (2016) 3.79
    3.7918816 = sum of:
      3.7918816 = weight(author_txt:rijke in 4972) [ClassicSimilarity], result of:
        3.7918816 = fieldWeight in 4972, product of:
          1.0 = tf(freq=1.0), with freq of:
            1.0 = termFreq=1.0
          8.667158 = idf(docFreq=19, maxDocs=42740)
          0.4375 = fieldNorm(doc=4972)
    

Similar documents (content)

  1. Vidinli, I.B.; Ozcan, R.: New query suggestion framework and algorithms : a case study for an educational search engine (2016) 0.28
    0.27853835 = sum of:
      0.27853835 = product of:
        0.8704324 = sum of:
          0.014515547 = weight(abstract_txt:method in 5186) [ClassicSimilarity], result of:
            0.014515547 = score(doc=5186,freq=1.0), product of:
              0.041091017 = queryWeight, product of:
                4.5216455 = idf(docFreq=1262, maxDocs=42740)
                0.009087625 = queryNorm
              0.35325354 = fieldWeight in 5186, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                4.5216455 = idf(docFreq=1262, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.026360236 = weight(abstract_txt:engine in 5186) [ClassicSimilarity], result of:
            0.026360236 = score(doc=5186,freq=1.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.43098137 = fieldWeight in 5186, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.005390323 = weight(abstract_txt:that in 5186) [ClassicSimilarity], result of:
            0.005390323 = score(doc=5186,freq=1.0), product of:
              0.028812513 = queryWeight, product of:
                1.3239974 = boost
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.009087625 = queryNorm
              0.18708271 = fieldWeight in 5186, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.08463881 = weight(abstract_txt:suggestions in 5186) [ClassicSimilarity], result of:
            0.08463881 = score(doc=5186,freq=1.0), product of:
              0.18066928 = queryWeight, product of:
                3.315421 = boost
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.009087625 = queryNorm
              0.46847373 = fieldWeight in 5186, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.17128448 = weight(abstract_txt:session in 5186) [ClassicSimilarity], result of:
            0.17128448 = score(doc=5186,freq=1.0), product of:
              0.3233647 = queryWeight, product of:
                5.2481575 = boost
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.009087625 = queryNorm
              0.52969444 = fieldWeight in 5186, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.086491905 = weight(abstract_txt:search in 5186) [ClassicSimilarity], result of:
            0.086491905 = score(doc=5186,freq=2.0), product of:
              0.21438526 = queryWeight, product of:
                6.4605427 = boost
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.009087625 = queryNorm
              0.4034415 = fieldWeight in 5186, product of:
                1.4142135 = tf(freq=2.0), with freq of:
                  2.0 = termFreq=2.0
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.17561492 = weight(abstract_txt:queries in 5186) [ClassicSimilarity], result of:
            0.17561492 = score(doc=5186,freq=2.0), product of:
              0.31232443 = queryWeight, product of:
                6.7531304 = boost
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.009087625 = queryNorm
              0.56228364 = fieldWeight in 5186, product of:
                1.4142135 = tf(freq=2.0), with freq of:
                  2.0 = termFreq=2.0
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
          0.30613616 = weight(abstract_txt:query in 5186) [ClassicSimilarity], result of:
            0.30613616 = score(doc=5186,freq=8.0), product of:
              0.29269063 = queryWeight, product of:
                6.8043656 = boost
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.009087625 = queryNorm
              1.0459377 = fieldWeight in 5186, product of:
                2.828427 = tf(freq=8.0), with freq of:
                  8.0 = termFreq=8.0
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.078125 = fieldNorm(doc=5186)
        0.32 = coord(8/25)
    
  2. Jung, S.; Herlocker, J.L.; Webster, J.: Click data as implicit relevance feedback in web search (2007) 0.26
    0.26216933 = sum of:
      0.26216933 = product of:
        0.7282481 = sum of:
          0.013090008 = weight(abstract_txt:focus in 2913) [ClassicSimilarity], result of:
            0.013090008 = score(doc=2913,freq=1.0), product of:
              0.048650336 = queryWeight, product of:
                1.0881016 = boost
                4.92001 = idf(docFreq=847, maxDocs=42740)
                0.009087625 = queryNorm
              0.26906306 = fieldWeight in 2913, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                4.92001 = idf(docFreq=847, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.018452164 = weight(abstract_txt:address in 2913) [ClassicSimilarity], result of:
            0.018452164 = score(doc=2913,freq=1.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.30168694 = fieldWeight in 2913, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.03196009 = weight(abstract_txt:engine in 2913) [ClassicSimilarity], result of:
            0.03196009 = score(doc=2913,freq=3.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.5225372 = fieldWeight in 2913, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.009983017 = weight(abstract_txt:that in 2913) [ClassicSimilarity], result of:
            0.009983017 = score(doc=2913,freq=7.0), product of:
              0.028812513 = queryWeight, product of:
                1.3239974 = boost
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.009087625 = queryNorm
              0.346482 = fieldWeight in 2913, product of:
                2.6457512 = tf(freq=7.0), with freq of:
                  7.0 = termFreq=7.0
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.06653364 = weight(abstract_txt:sessions in 2913) [ClassicSimilarity], result of:
            0.06653364 = score(doc=2913,freq=1.0), product of:
              0.18120219 = queryWeight, product of:
                2.969773 = boost
                6.7141304 = idf(docFreq=140, maxDocs=42740)
                0.009087625 = queryNorm
              0.367179 = fieldWeight in 2913, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                6.7141304 = idf(docFreq=140, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.23979826 = weight(abstract_txt:session in 2913) [ClassicSimilarity], result of:
            0.23979826 = score(doc=2913,freq=4.0), product of:
              0.3233647 = queryWeight, product of:
                5.2481575 = boost
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.009087625 = queryNorm
              0.74157214 = fieldWeight in 2913, product of:
                2.0 = tf(freq=4.0), with freq of:
                  4.0 = termFreq=4.0
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.15435836 = weight(abstract_txt:search in 2913) [ClassicSimilarity], result of:
            0.15435836 = score(doc=2913,freq=13.0), product of:
              0.21438526 = queryWeight, product of:
                6.4605427 = boost
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.009087625 = queryNorm
              0.72000456 = fieldWeight in 2913, product of:
                3.6055512 = tf(freq=13.0), with freq of:
                  13.0 = termFreq=13.0
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.08692495 = weight(abstract_txt:queries in 2913) [ClassicSimilarity], result of:
            0.08692495 = score(doc=2913,freq=1.0), product of:
              0.31232443 = queryWeight, product of:
                6.7531304 = boost
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.009087625 = queryNorm
              0.2783162 = fieldWeight in 2913, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
          0.107147664 = weight(abstract_txt:query in 2913) [ClassicSimilarity], result of:
            0.107147664 = score(doc=2913,freq=2.0), product of:
              0.29269063 = queryWeight, product of:
                6.8043656 = boost
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.009087625 = queryNorm
              0.3660782 = fieldWeight in 2913, product of:
                1.4142135 = tf(freq=2.0), with freq of:
                  2.0 = termFreq=2.0
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.0546875 = fieldNorm(doc=2913)
        0.36 = coord(9/25)
    
  3. Lewandowski, D.: Evaluating the retrieval effectiveness of web search engines using a representative query sample (2015) 0.24
    0.24360251 = sum of:
      0.24360251 = product of:
        0.7612579 = sum of:
          0.026360236 = weight(abstract_txt:address in 4158) [ClassicSimilarity], result of:
            0.026360236 = score(doc=4158,freq=1.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.43098137 = fieldWeight in 4158, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.04565727 = weight(abstract_txt:engine in 4158) [ClassicSimilarity], result of:
            0.04565727 = score(doc=4158,freq=3.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.74648166 = fieldWeight in 4158, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.026360236 = weight(abstract_txt:scale in 4158) [ClassicSimilarity], result of:
            0.026360236 = score(doc=4158,freq=1.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.43098137 = fieldWeight in 4158, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.009336313 = weight(abstract_txt:that in 4158) [ClassicSimilarity], result of:
            0.009336313 = score(doc=4158,freq=3.0), product of:
              0.028812513 = queryWeight, product of:
                1.3239974 = boost
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.009087625 = queryNorm
              0.32403675 = fieldWeight in 4158, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.039582435 = weight(abstract_txt:type in 4158) [ClassicSimilarity], result of:
            0.039582435 = score(doc=4158,freq=1.0), product of:
              0.10104999 = queryWeight, product of:
                2.217735 = boost
                5.013906 = idf(docFreq=771, maxDocs=42740)
                0.009087625 = queryNorm
              0.3917114 = fieldWeight in 4158, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.013906 = idf(docFreq=771, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.12231802 = weight(abstract_txt:search in 4158) [ClassicSimilarity], result of:
            0.12231802 = score(doc=4158,freq=4.0), product of:
              0.21438526 = queryWeight, product of:
                6.4605427 = boost
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.009087625 = queryNorm
              0.5705524 = fieldWeight in 4158, product of:
                2.0 = tf(freq=4.0), with freq of:
                  4.0 = termFreq=4.0
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.30417398 = weight(abstract_txt:queries in 4158) [ClassicSimilarity], result of:
            0.30417398 = score(doc=4158,freq=6.0), product of:
              0.31232443 = queryWeight, product of:
                6.7531304 = boost
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.009087625 = queryNorm
              0.97390383 = fieldWeight in 4158, product of:
                2.4494898 = tf(freq=6.0), with freq of:
                  6.0 = termFreq=6.0
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
          0.18746935 = weight(abstract_txt:query in 4158) [ClassicSimilarity], result of:
            0.18746935 = score(doc=4158,freq=3.0), product of:
              0.29269063 = queryWeight, product of:
                6.8043656 = boost
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.009087625 = queryNorm
              0.6405034 = fieldWeight in 4158, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.078125 = fieldNorm(doc=4158)
        0.32 = coord(8/25)
    
  4. Kim, Y.; Seo, J.; Croft, W.B.; Smith, D.A.: Automatic suggestion of phrasal-concept queries for literature search (2014) 0.24
    0.23946503 = sum of:
      0.23946503 = product of:
        0.7483282 = sum of:
          0.014248086 = weight(abstract_txt:effective in 4693) [ClassicSimilarity], result of:
            0.014248086 = score(doc=4693,freq=1.0), product of:
              0.047094367 = queryWeight, product of:
                1.07056 = boost
                4.840693 = idf(docFreq=917, maxDocs=42740)
                0.009087625 = queryNorm
              0.3025433 = fieldWeight in 4693, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                4.840693 = idf(docFreq=917, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.004312258 = weight(abstract_txt:that in 4693) [ClassicSimilarity], result of:
            0.004312258 = score(doc=4693,freq=1.0), product of:
              0.028812513 = queryWeight, product of:
                1.3239974 = boost
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.009087625 = queryNorm
              0.14966616 = fieldWeight in 4693, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.029834246 = weight(abstract_txt:find in 4693) [ClassicSimilarity], result of:
            0.029834246 = score(doc=4693,freq=1.0), product of:
              0.09711463 = queryWeight, product of:
                2.1741219 = boost
                4.915304 = idf(docFreq=851, maxDocs=42740)
                0.009087625 = queryNorm
              0.3072065 = fieldWeight in 4693, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                4.915304 = idf(docFreq=851, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.11727898 = weight(abstract_txt:suggestions in 4693) [ClassicSimilarity], result of:
            0.11727898 = score(doc=4693,freq=3.0), product of:
              0.18066928 = queryWeight, product of:
                3.315421 = boost
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.009087625 = queryNorm
              0.64913625 = fieldWeight in 4693, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.1137461 = weight(abstract_txt:academic in 4693) [ClassicSimilarity], result of:
            0.1137461 = score(doc=4693,freq=3.0), product of:
              0.22303441 = queryWeight, product of:
                5.2095175 = boost
                4.711118 = idf(docFreq=1044, maxDocs=42740)
                0.009087625 = queryNorm
              0.5099935 = fieldWeight in 4693, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                4.711118 = idf(docFreq=1044, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.084744416 = weight(abstract_txt:search in 4693) [ClassicSimilarity], result of:
            0.084744416 = score(doc=4693,freq=3.0), product of:
              0.21438526 = queryWeight, product of:
                6.4605427 = boost
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.009087625 = queryNorm
              0.39529032 = fieldWeight in 4693, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.17206676 = weight(abstract_txt:queries in 4693) [ClassicSimilarity], result of:
            0.17206676 = score(doc=4693,freq=3.0), product of:
              0.31232443 = queryWeight, product of:
                6.7531304 = boost
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.009087625 = queryNorm
              0.55092317 = fieldWeight in 4693, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                5.0892105 = idf(docFreq=715, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
          0.21209736 = weight(abstract_txt:query in 4693) [ClassicSimilarity], result of:
            0.21209736 = score(doc=4693,freq=6.0), product of:
              0.29269063 = queryWeight, product of:
                6.8043656 = boost
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.009087625 = queryNorm
              0.7246469 = fieldWeight in 4693, product of:
                2.4494898 = tf(freq=6.0), with freq of:
                  6.0 = termFreq=6.0
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.0625 = fieldNorm(doc=4693)
        0.32 = coord(8/25)
    
  5. Huang, C.-K.; Chien, L.-F.; Oyang, Y.-J.: Relevant term suggestion in interactive Web search based on contextual information in query session logs (2003) 0.23
    0.2332064 = sum of:
      0.2332064 = product of:
        0.72877 = sum of:
          0.024678407 = weight(abstract_txt:effective in 2613) [ClassicSimilarity], result of:
            0.024678407 = score(doc=2613,freq=3.0), product of:
              0.047094367 = queryWeight, product of:
                1.07056 = boost
                4.840693 = idf(docFreq=917, maxDocs=42740)
                0.009087625 = queryNorm
              0.5240204 = fieldWeight in 2613, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                4.840693 = idf(docFreq=917, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.021088189 = weight(abstract_txt:engine in 2613) [ClassicSimilarity], result of:
            0.021088189 = score(doc=2613,freq=1.0), product of:
              0.061163284 = queryWeight, product of:
                1.220034 = boost
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.009087625 = queryNorm
              0.3447851 = fieldWeight in 2613, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                5.5165615 = idf(docFreq=466, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.00746905 = weight(abstract_txt:that in 2613) [ClassicSimilarity], result of:
            0.00746905 = score(doc=2613,freq=3.0), product of:
              0.028812513 = queryWeight, product of:
                1.3239974 = boost
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.009087625 = queryNorm
              0.2592294 = fieldWeight in 2613, product of:
                1.7320508 = tf(freq=3.0), with freq of:
                  3.0 = termFreq=3.0
                2.3946586 = idf(docFreq=10595, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.07603844 = weight(abstract_txt:sessions in 2613) [ClassicSimilarity], result of:
            0.07603844 = score(doc=2613,freq=1.0), product of:
              0.18120219 = queryWeight, product of:
                2.969773 = boost
                6.7141304 = idf(docFreq=140, maxDocs=42740)
                0.009087625 = queryNorm
              0.41963315 = fieldWeight in 2613, product of:
                1.0 = tf(freq=1.0), with freq of:
                  1.0 = termFreq=1.0
                6.7141304 = idf(docFreq=140, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.09575788 = weight(abstract_txt:suggestions in 2613) [ClassicSimilarity], result of:
            0.09575788 = score(doc=2613,freq=2.0), product of:
              0.18066928 = queryWeight, product of:
                3.315421 = boost
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.009087625 = queryNorm
              0.5300175 = fieldWeight in 2613, product of:
                1.4142135 = tf(freq=2.0), with freq of:
                  2.0 = termFreq=2.0
                5.996464 = idf(docFreq=288, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.19378625 = weight(abstract_txt:session in 2613) [ClassicSimilarity], result of:
            0.19378625 = score(doc=2613,freq=2.0), product of:
              0.3233647 = queryWeight, product of:
                5.2481575 = boost
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.009087625 = queryNorm
              0.5992808 = fieldWeight in 2613, product of:
                1.4142135 = tf(freq=2.0), with freq of:
                  2.0 = termFreq=2.0
                6.7800884 = idf(docFreq=131, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.09785442 = weight(abstract_txt:search in 2613) [ClassicSimilarity], result of:
            0.09785442 = score(doc=2613,freq=4.0), product of:
              0.21438526 = queryWeight, product of:
                6.4605427 = boost
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.009087625 = queryNorm
              0.45644194 = fieldWeight in 2613, product of:
                2.0 = tf(freq=4.0), with freq of:
                  4.0 = termFreq=4.0
                3.6515355 = idf(docFreq=3014, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
          0.21209736 = weight(abstract_txt:query in 2613) [ClassicSimilarity], result of:
            0.21209736 = score(doc=2613,freq=6.0), product of:
              0.29269063 = queryWeight, product of:
                6.8043656 = boost
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.009087625 = queryNorm
              0.7246469 = fieldWeight in 2613, product of:
                2.4494898 = tf(freq=6.0), with freq of:
                  6.0 = termFreq=6.0
                4.7333736 = idf(docFreq=1021, maxDocs=42740)
                0.0625 = fieldNorm(doc=2613)
        0.32 = coord(8/25)