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891.
892.
We explore the feasibility of automatically identifying sentences in different MEDLINE abstracts that are related in meaning.
We compared traditional vector space models with machine learning methods for detecting relatedness, and found that machine
learning was superior. The Huber method, a variant of Support Vector Machines which minimizes the modified Huber loss function,
achieves 73% precision when the score cutoff is set high enough to identify about one related sentence per abstract on average.
We illustrate how an abstract viewed in PubMed might be modified to present the related sentences found in other abstracts
by this automatic procedure. 相似文献
893.
David E. Losada 《Information Retrieval》2010,13(5):485-506
The retrieval of sentences that are relevant to a given information need is a challenging passage retrieval task. In this
context, the well-known vocabulary mismatch problem arises severely because of the fine granularity of the task. Short queries,
which are usually the rule rather than the exception, aggravate the problem. Consequently, effective sentence retrieval methods
tend to apply some form of query expansion, usually based on pseudo-relevance feedback. Nevertheless, there are no extensive
studies comparing different statistical expansion strategies for sentence retrieval. In this work we study thoroughly the
effect of distinct statistical expansion methods on sentence retrieval. We start from a set of retrieved documents in which
relevant sentences have to be found. In our experiments different term selection strategies are evaluated and we provide empirical
evidence to show that expansion before sentence retrieval yields competitive performance. This is particularly novel because expansion for sentence retrieval is often done after sentence retrieval (i.e. expansion terms are mined from a ranked set of sentences) and there are no comparative results available between both
types of expansion. Furthermore, this comparison is particularly valuable because there are important implications in time
efficiency. We also carefully analyze expansion on weak and strong queries and demonstrate clearly that expanding queries
before sentence retrieval is not only more convenient for efficiency purposes, but also more effective when handling poor
queries. 相似文献
894.
895.
896.
Business opportunities in international markets are largely determined by accessibility, transparency, and legal frameworks
fair to all parties concerned. Arab book markets in principle offer a tremendous potential with more than 300 million readers
sharing one common language. Besides unsolved censorship issues, problems with money collection, and differing regulations,
however, the lack of a uniform book distribution system is the most critical hurdle for the development of a common Arabic
book market. Most importantly, there is no comprehensive database containing accurate content briefs, background information
on authors, ISBN numbers, and publisher company information as well as all relevant commercial data such as book prices, weight,
logistics terms, and availability. Authors and publishers are hard hit as they often need to organize book transportation,
delivery, and invoice collection on their own. At present, “selling book fairs” in the Arab world—with the exception of Abu
Dhabi International Book Fair—present themselves as crowded book bazaars rather than executive meeting points. The authors
of the article, however, are anticipating change: New distribution initiatives will soon interlink regional Arabic markets
and create unique growth and profit opportunities. 相似文献
897.
Donghee Sinn 《Archival Science》2010,10(2):117-140
Archivists have long tried to understand users from the viewpoint of their archival collections. Such an approach misses important
perspectives about use in, and users of, archives; how they perform research and develop knowledge while using archives. This
study aims to comprehend the use of archival materials in research from the users’ perspective. It attempts to understand
users’ perceptions of the impact of archival collections on their research, how and when archival materials are involved in
the research process and how much weight they grant those materials in support of their thesis, from an actual research topic,
the No Gun Ri massacre. The case of the No Gun Ri incident provides a good example of how archival materials play a role in historical discussions and an opportunity to look
at archival contributions. No Gun Ri researchers acknowledged that archival documents were essential source materials for details about the incident and a major
player in stimulating controversies and, consequently, provided the impetus for further publications. General recordkeeping
situations also provided a circumstantial context of the incident. However, No Gun Ri researchers agreed that oral history was the most valuable and influential evidence for their major ideas and used archival
documents to provide hard facts about the details of oral history. There are some unique research patterns of No Gun Ri researchers identified in this study which are different from the typical assumptions of archivists. 相似文献
898.
Nicholas Popper 《Archival Science》2010,10(3):249-266
This article investigates the long-term transformations in England’s documentary storage regime wrought by the Reformation.
Henry VIII’s Dissolution of the Monasteries famously resulted in the dispersal and destruction of many medieval texts and
records, but he and his successors sponsored efforts to retrieve lost materials, which they then used in the formation of
ecclesiastical policy. Elizabethan counselors expanded the scope of this project, applying their expertise in gathering records
to secular issues and assiduously preserving their own documents. During James I’s reign, the Earl of Salisbury’s patronage
gave new authority to the State Paper Office, encouraging the consolidation of a centralizing archive that integrated earlier
methods of collection, preservation, and indexing in its operation and construction. The article thus offers an analytic trajectory
tying the practices of Reformation to the development of expanding national archives in the seventeenth century. 相似文献
899.
Timothy John Lovering 《Archival Science》2010,10(1):1-23
Recordkeeping in twentieth century colonial states has been ignored by scholars, or at best regarded as the result of a monolithic
process of migration of metropolitan practices. Registries provided the principal organ of recordkeeping in British government
systems of administration. This comparative study of the registries in the neighbouring territories of Northern Rhodesia (now
Zambia) and Nyasaland (now Malawi) reveals the true extent of metropolitan British influence, exposing an absence of centralised
advice, and a consequent dependence upon individual innovation. This engendered divergent and sometimes weak recordkeeping
regimes. The effects of this included the diminution of fiduciary responsibility and administrative accountability. 相似文献
900.
Recently direct optimization of information retrieval (IR) measures has become a new trend in learning to rank. In this paper,
we propose a general framework for direct optimization of IR measures, which enjoys several theoretical advantages. The general
framework, which can be used to optimize most IR measures, addresses the task by approximating the IR measures and optimizing
the approximated surrogate functions. Theoretical analysis shows that a high approximation accuracy can be achieved by the
framework. We take average precision (AP) and normalized discounted cumulated gains (NDCG) as examples to demonstrate how
to realize the proposed framework. Experiments on benchmark datasets show that the algorithms deduced from our framework are
very effective when compared to existing methods. The empirical results also agree well with the theoretical results obtained
in the paper. 相似文献