Search (9 results, page 1 of 1)

0.04172619 = product of:
  0.08345238 = sum of:
    0.05173004 = weight(_text_:data in 3107) [ClassicSimilarity], result of:
      0.05173004 = score(doc=3107,freq=2.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.34936053 = fieldWeight in 3107, product of:
          1.4142135 = tf(freq=2.0), with freq of:
            2.0 = termFreq=2.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.078125 = fieldNorm(doc=3107)
    0.03172234 = product of:
      0.06344468 = sum of:
        0.06344468 = weight(_text_:22 in 3107) [ClassicSimilarity], result of:
          0.06344468 = score(doc=3107,freq=2.0), product of:
            0.16398162 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.046827413 = queryNorm
            0.38690117 = fieldWeight in 3107, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.078125 = fieldNorm(doc=3107)
      0.5 = coord(1/2)
  0.5 = coord(2/4)

Date

27. 2.1999 20:59:22

0.021947198 = product of:
  0.08778879 = sum of:
    0.08778879 = weight(_text_:data in 7571) [ClassicSimilarity], result of:
      0.08778879 = score(doc=7571,freq=4.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.5928845 = fieldWeight in 7571, product of:
          2.0 = tf(freq=4.0), with freq of:
            4.0 = termFreq=4.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.09375 = fieldNorm(doc=7571)
  0.25 = coord(1/4)

0.015519011 = product of:
  0.062076043 = sum of:
    0.062076043 = weight(_text_:data in 5671) [ClassicSimilarity], result of:
      0.062076043 = score(doc=5671,freq=8.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.4192326 = fieldWeight in 5671, product of:
          2.828427 = tf(freq=8.0), with freq of:
            8.0 = termFreq=8.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046875 = fieldNorm(doc=5671)
  0.25 = coord(1/4)

Abstract

Recommender systems may accelerate knowledge discovery in many fields. However, their users may be competitors guarding their ideas before publication or for other reasons. We describe a simulation experiment to assess user privacy against targeted attacks, modeling recommendations based on co-access data. The analysis uses an unusually long (14?years) set of anonymized historical data on user-item accesses. We introduce the notions of "visibility" and "discoverability." We find, based on historical data, that the majority of the actions of arXiv users would be potentially "visible" under targeted attack. However, "discoverability," which incorporates the difficulty of actually seeing a "visible" effect, is very much lower for nearly all users. We consider the effect of changes to the settings of the recommender algorithm on the visibility and discoverability of user actions and propose mitigation strategies that reduce both measures of risk.

0.011102819 = product of:
  0.044411276 = sum of:
    0.044411276 = product of:
      0.08882255 = sum of:
        0.08882255 = weight(_text_:22 in 4112) [ClassicSimilarity], result of:
          0.08882255 = score(doc=4112,freq=2.0), product of:
            0.16398162 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.046827413 = queryNorm
            0.5416616 = fieldWeight in 4112, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.109375 = fieldNorm(doc=4112)
      0.5 = coord(1/2)
  0.25 = coord(1/4)

Source

Bulletin of the American Society for Information Science. 28(2002) no.6, S.22-24

0.009144665 = product of:
  0.03657866 = sum of:
    0.03657866 = weight(_text_:data in 6711) [ClassicSimilarity], result of:
      0.03657866 = score(doc=6711,freq=4.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.24703519 = fieldWeight in 6711, product of:
          2.0 = tf(freq=4.0), with freq of:
            4.0 = termFreq=4.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.0390625 = fieldNorm(doc=6711)
  0.25 = coord(1/4)

Abstract

In anticipation of the explosive growth of digital libraries, a complex study was undertaken seeking to evaluate 21 diverse services at 5 major academic research libraries. This work stands as a model for evaluation of digital libraries, through its focus on both the costs of operations and the impacts of the services that those operations provide. The data have been analyzed using both statistical methods and methods of Data Envelopment Analysis. The results of the study, which are presented in detail, serve to demonstrate that a cross-functional approach to library services is feasible. They also highlight a new measure of impact, which is a weighted logarithmic combination of the amount of time that users spend interacting with the service, combined with a Likert-scale indication of the value of that service in relation to the time expended. The measure derived, incorporating simple information obtainable from the user, together with information which is readily available in server/client logs, provides an excellent foundation for transferring these measurement principles to the Digital Library environment

0.009144665 = product of:
  0.03657866 = sum of:
    0.03657866 = weight(_text_:data in 6712) [ClassicSimilarity], result of:
      0.03657866 = score(doc=6712,freq=4.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.24703519 = fieldWeight in 6712, product of:
          2.0 = tf(freq=4.0), with freq of:
            4.0 = termFreq=4.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.0390625 = fieldNorm(doc=6712)
  0.25 = coord(1/4)

Abstract

Previous models of searching behavior have taken as their foundation the Markov model of random processes. In this model, the next action that a user takes is determined by a probabilistic rule which is conditioned by the most recent experiences of the user. This model, which has achieved very limited success in describing real data, is at odds with the evidence of introspection in a crucial way. Introspection reveals that when we search we are, more or less, in a state of expectancy, which can be satisfied in a number of ways. In addition, the state can be modified by the accumulated evidence of our searches. The Markov model approach can not readily accommodate such persistence of intention and behavior. The Petri Net model, which has been developed to analyze the interdependencies among events in a communications network, can be adapted to this situation. In this adaptation, the so-called "transitions" of the Petri Net occur only when their necessary pre-conditions have been met. We are able to show that various key abstractions of information finding, such as "document relevance", "a desired number of relevant documents", "discouragement", "exhaustion" and "satisfaction" can all be modeled using the Petri Net framework. Further, we show that this model leads naturally to a new approach to the collection of user data, and to the analysis of transaction logs, by providing a far richer description of the user's present state, without inducing a combinatorial explosion

0.0077595054 = product of:
  0.031038022 = sum of:
    0.031038022 = weight(_text_:data in 353) [ClassicSimilarity], result of:
      0.031038022 = score(doc=353,freq=2.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.2096163 = fieldWeight in 353, product of:
          1.4142135 = tf(freq=2.0), with freq of:
            2.0 = termFreq=2.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046875 = fieldNorm(doc=353)
  0.25 = coord(1/4)

Abstract

Details with specifics of the study: importance of taxonomy; the method used for gathering data on user assessments of value in 5 research libraries, involving 18 services and 528 interviews with users; development and presentation of the taxonomy; and statistics and tests of the taxonomy. A novel aspect is the division of value of information services into 3 general classes or facets; reasons for use of a service in the given instance; quality of interaction (use) related to that service; and worth, benefits, or implications of subsequent results from use

0.006466255 = product of:
  0.02586502 = sum of:
    0.02586502 = weight(_text_:data in 6701) [ClassicSimilarity], result of:
      0.02586502 = score(doc=6701,freq=2.0), product of:
        0.14807065 = queryWeight, product of:
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.046827413 = queryNorm
        0.17468026 = fieldWeight in 6701, product of:
          1.4142135 = tf(freq=2.0), with freq of:
            2.0 = termFreq=2.0
          3.1620505 = idf(docFreq=5088, maxDocs=44218)
          0.0390625 = fieldNorm(doc=6701)
  0.25 = coord(1/4)

Abstract

As libraries evolve from paper based to digitized collection, traditional measurement activities must change. To demonstrate the growth in library value during this transition period, libraries must be able to describe how library inputs are transformed into the services libraries render. We apply a complex tool, data envelopment analysis (DEA), to evaluate the relative efficiency of major academic research libraries that are members of the Association of Research Libraries (ARL). An efficient library is defined as the one which produces same output with less input or, for a given input, produces more output. We report the results of a two-year base line study using traditional measures taken from 1995-1996 ARL statistics. We observe the patterns of efficiency scores of both individual libraries and libraries in peer groups (private vs. public). In particular we study the consistency over the years of specific DEA measures. This consistency provides justification for extending DEA as libraries undergo revolutionary digital transformation. The results are also corroborated using standard statistical measures. DEA application in the new digital library environment is discussed

0.0055514094 = product of:
  0.022205638 = sum of:
    0.022205638 = product of:
      0.044411276 = sum of:
        0.044411276 = weight(_text_:22 in 5267) [ClassicSimilarity], result of:
          0.044411276 = score(doc=5267,freq=2.0), product of:
            0.16398162 = queryWeight, product of:
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.046827413 = queryNorm
            0.2708308 = fieldWeight in 5267, product of:
              1.4142135 = tf(freq=2.0), with freq of:
                2.0 = termFreq=2.0
              3.5018296 = idf(docFreq=3622, maxDocs=44218)
              0.0546875 = fieldNorm(doc=5267)
      0.5 = coord(1/2)
  0.25 = coord(1/4)

Date

22. 7.2006 15:05:39