Interactive Paraphrasing Based on Linguistic Annotation
Ryuichiro Higashinaka
Katashi Nagao
Keio Research Institute at SFC
Dept. of Information Engineering, Nagoya University
5322 Endo, Fujisawa-shi, Kanagawa 252-8520, Japan
Furo-cho, Chikusa-ku, Nagoya 464-8603, Japanrh@sfc.keio.ac.jp
nagao@nuie.nagoya-u.ac.jp

1. Introduction
Background : Large number of documents of great diversity on the Web is making some of thedocuments difficult to understand for some users due to lack of background knowledge.
Conventional Method : Automatic consultation of online dictionaries with a popup window to show
word definitions, usually triggered by mouse movements.
Problems : 1. Difficulty of word sense disambiguation
In case of polysemic words, all possible word sense candidates are usually displayed,forcing the viewer to choose the correct meaning.
2. Dictionary lookup results are independent definition statements
The user has to reread the original document, taking the word definition into account.
3. NLP is not directly applicable to dictionary lookup results
Natural language processing techniques such as summarization, translation, and voicesynthesis cannot be easily applied to the results.
The ``Interactive Paraphrasing”, making use of linguistic annotation associated with the document
and online dictionaries, paraphrases words on user demand solving above three problems.

2. Example
Original
Document

The conventional
method : popup
window, showing
the word definition

After paraphrasing``agents” and``deployed”

After paraphrasing``authority” in thealready paraphrasedarea

3. Linguistic Annotation
Linguistic annotation consists of word sense annotation and syntactic annotation.
Word Sense Annotation
Syntactic Annotation
We annotate polysemic words in the document
Syntactic annotation gives a syntactic structure to thewith word sense, so that their word definitions
document on the basis of a new tag set proposed bycan be retrieved uniquely from online dictionaries. the GDA (Global Document Annotation) project,
We use WordNet for word sense notation.
enabling the intelligent processing of documents. We
also use PennTreeBank tag set as a syntactic feature.
<su id="id1-0" ptb="S"><ajp ptb="DT">the</ajp><n bf="power" ptb="NN“
sense=“power-noun-1“ >power</n><adp><ad ptb="TO">to</ad><vp><v bf="make" ptb="VB">make</v><np ptb="NPL NNS">decisions</np></vp>
Example of an</adp>
annotated text.</su>

Using our Annotation Editor,
users can interactively annotate
documents with linguistic
structure (syntactic and semanticstructure) and word senses.
The editor is capable offundamental natural language
processing and interactive
disambiguation.

Interactive Paraphrasing Based on Linguistic Annotation
Ryuichiro Higashinaka
Katashi Nagao
Keio Research Institute at SFC
Dept. of Information Engineering, Nagoya University5322 Endo, Fujisawa-shi, Kanagawa 252-8520, Japan
Furo-cho, Chikusa-ku, Nagoya 464-8603, Japanrh@sfc.keio.ac.jp
nagao@nuie.nagoya-u.ac.jp

4. Interactive Paraphrasing
Features :1. Users can interactively select words to paraphrase by mouse clicks on normal Web browsers.
2. Paraphrasing history is stored for profile-based paraphrasing, which automatically selects words
to paraphrase based on user's knowledge. (not yet implemented)
3. Resulting sentence can also be the target for the next paraphrase. By allowing incremental
operation, users can interact with the document until there are no paraphrasable words in thedocument.
Paraphrasing Mechanism :example of an annotatedword sense definition
example ofsu sense = deploy-verb-2
ansu
annotated
sense = deploy-verb-2
replacing nodes
text
ad
vp
= paraphrasing
np
vp
vp
v
adp
ajp

n

Some agents have been deployed

adonv

np
ajp

ntheWeb.

5. Paraphrasing Rules

adp
adp

ad adpto distribute systematically or strategically

6. Implementation• Paraphrasing rules are node replacing rules.
• There are two types of rules.
1. Global rules are applied to any pair ofnodes.
e.g.,•Avoid double negation, which increases thecomplexity of the sentence.
•To avoid redundancy, remove the samecase-marked structure found in bothstructures from the definition nodes.

2.

Local rules are applied depending on
the syntactic features of the nodes.

e.g.,•When replacing verb node(A) with verb
node(B), apply A's conjugation to B andreplace A with B.
•When replacing noun node(A) with nounnode(B), replace A with B agreeing in number.

7. Summary and Future Plans
We have presented a method, ``Interactive Paraphrasing”, which enables users to interactively
paraphrase words in a document by their definitions, making use of syntactic annotation and word
sense annotation. ``Interactive Paraphrasing” enhances the accessibility and the reuse of documents.
Our future plans include: reduction of the annotation cost, realization of profile-based paraphrasing using
personal paraphrasing history, and retrieval and semantic merging of similar documents using linguistic
annotation.