119 lines
4.4 KiB
Plaintext
119 lines
4.4 KiB
Plaintext
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=======
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Introduction
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This README v2.0 (June, 2004) for the v2.0 polarity dataset comes from
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the URL http://www.cs.cornell.edu/people/pabo/movie-review-data .
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=======
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What's New -- June, 2004
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This dataset represents an enhancement of the review corpus v1.0
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described in README v1.1: it contains more reviews, and labels were
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created with an improved rating-extraction system.
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=======
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Citation Info
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This data was first used in Bo Pang and Lillian Lee,
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``A Sentimental Education: Sentiment Analysis Using Subjectivity Summarization
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Based on Minimum Cuts'', Proceedings of the ACL, 2004.
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@InProceedings{Pang+Lee:04a,
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author = {Bo Pang and Lillian Lee},
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title = {A Sentimental Education: Sentiment Analysis Using Subjectivity Summarization Based on Minimum Cuts},
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booktitle = "Proceedings of the ACL",
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year = 2004
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}
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=======
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Data Format Summary
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- review_polarity.tar.gz: contains this readme and data used in
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the experiments described in Pang/Lee ACL 2004.
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Specifically:
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Within the folder "txt_sentoken" are the 2000 processed down-cased
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text files used in Pang/Lee ACL 2004; the names of the two
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subdirectories in that folder, "pos" and "neg", indicate the true
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classification (sentiment) of the component files according to our
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automatic rating classifier (see section "Rating Decision" below).
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File names consist of a cross-validation tag plus the name of the
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original html file. The ten folds used in the Pang/Lee ACL 2004 paper's
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experiments were:
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fold 1: files tagged cv000 through cv099, in numerical order
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fold 2: files tagged cv100 through cv199, in numerical order
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...
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fold 10: files tagged cv900 through cv999, in numerical order
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Hence, the file neg/cv114_19501.txt, for example, was labeled as
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negative, served as a member of fold 2, and was extracted from the
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file 19501.html in polarity_html.zip (see below).
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Each line in each text file corresponds to a single sentence, as
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determined by Adwait Ratnaparkhi's sentence boundary detector
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MXTERMINATOR.
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Preliminary steps were taken to remove rating information from the
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text files, but only the rating information upon which the rating
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decision was based is guaranteed to have been removed. Thus, if the
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original review contains several instances of rating information,
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potentially given in different forms, those not recognized as valid
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ratings remain part of the review text.
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- polarity_html.zip: The original source files from which the
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processed, labeled, and (randomly) selected data in
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review_polarity.tar.gz was derived.
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Specifically:
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This data consists of unprocessed, unlabeled html files from the
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IMDb archive of the rec.arts.movies.reviews newsgroup,
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http://reviews.imdb.com/Reviews. The files in review_polarity.tar.gz
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represent a processed subset of these files.
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=======
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Rating Decision (Appendix A)
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This section describes how we determined whether a review was positive
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or negative.
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The original html files do not have consistent formats -- a review may
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not have the author's rating with it, and when it does, the rating can
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appear at different places in the file in different forms. We only
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recognize some of the more explicit ratings, which are extracted via a
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set of ad-hoc rules. In essence, a file's classification is determined
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based on the first rating we were able to identify.
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- In order to obtain more accurate rating decisions, the maximum
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rating must be specified explicitly, both for numerical ratings
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and star ratings. ("8/10", "four out of five", and "OUT OF
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****: ***" are examples of rating indications we recognize.)
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- With a five-star system (or compatible number systems):
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three-and-a-half stars and up are considered positive,
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two stars and below are considered negative.
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- With a four-star system (or compatible number system):
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three stars and up are considered positive,
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one-and-a-half stars and below are considered negative.
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- With a letter grade system:
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B or above is considered positive,
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C- or below is considered negative.
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We attempted to recognize half stars, but they are specified in an
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especially free way, which makes them difficult to recognize. Hence,
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we may lose a half star very occasionally; but this only results in 2.5
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stars in five star system being categorized as negative, which is
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still reasonable.
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