a multilingual semantic wiki based on controlled natural language

A Multilingual Semantic Wiki Based onControlled Natural Language

Tobias Kuhn

Chair of Sociology, in particular of Modeling and Simulation, ETH Zurich,Switzerland

Insight, National University of Ireland, Galway19 August 2014

About This Talk

This talk is mainly based on the following papers:

Kaarel Kaljurand and Tobias Kuhn. A Multilingual Semantic WikiBased on Attempto Controlled English and Grammatical Framework.In Proceedings of the 10th Extended Semantic Web Conference(ESWC). 2013.http://purl.org/tkuhn/eswc2013acewikigf

Kaarel Kaljurand, Tobias Kuhn, and Laura Canedo. Collaborativemultilingual knowledge management based on controlled naturallanguage. Semantic Web. Accepted, to appear.http://www.semantic-web-journal.net/system/files/swj524.pdf

Tobias Kuhn, ETH Zurich A Multilingual Semantic Wiki 2 / 27

http://purl.org/tkuhn/eswc2013acewikigf

http://www.semantic-web-journal.net/system/files/swj524.pdf

Imagine ...

... that Wikipedia can check consistency and answerquestions about the contained knowledge, and

... that all content is instantly available in alllanguages!


• AceWiki is a semantic wiki

• Articles are written in Attempto Controlled English (ACE)

• These sentences are internally translated into the Semantic Weblanguage OWL

• An OWL reasoner is built in to answer questions and detectinconsistencies

• Special editor for writing ACE statements

• Extended to support multilinguality


Monolingual AceWiki: Screenshot


Attempto Controlled English (ACE)

Subset of natural English:

• Conjunction, disjunction, negation, if-then, ...

• Anaphoric references: pronouns, definite noun phrases, variables

• Quantifiers: every, no, at least 3, ...

• Content words: proper names, nouns, verbs, adjectives, ...

Grammar is fixed, but users can change content words.

Deterministic ambiguity handling:

• Anaphora resolution (France borders Spain and it bordersPortugal.)

• Quantifier scope (Every country borders a country.)

• Attachment (Every EU-country borders a country that is anEU-country and is a NATO-country.)

Well-defined translations to and from first-order logic, OWL, ...


Predictive Editor


Consistency Checking

AceWiki ensures consistency by checking every new statement:


Question Answering

AceWiki supports simple wh-questions:


Monolingual AceWiki: Demo

http://attempto.ifi.uzh.ch/acewiki/



ACE Reasoning via Translation to OWL

Every country that does not border a sea is a landlocked-country.

SubClassOf(

ObjectIntersectionOf(

:country

ObjectComplementOf(

ObjectSomeValuesFrom(

:border

:sea

)

)

)

:landlocked-country

)

Which country is a landlocked-country?


:country

:landlocked-country

)


Evaluation

Two small usability experiments with earlier versions of AceWiki:

• Altogether 26 untrained participants

• Task: Collaborative creation of a knowledge base

Results:

• 78%-81% of the sentences were correct and sensible

• 61%-70% of them were complex (containing negations,implications, disjunctions or number restrictions)

• Creation of a correct sentence every 5–6 minutes

• Definition of a new word every 5–7 minutes

→ Even untrained users can effectively use AceWiki


Multilingual AceWiki: AceWiki-GF

General ideas:

• Make wiki content available in different languages

• Automatically translated content using high-quality rule-basedmachine translation: Grammatical Framework (GF)

• Language switching like in Wikipedia

• Localization of the user interface


Grammatical Framework (GF)

GF is a framework for multilingual grammar engineering:

• Rule-based

• Functional programming language (based on Haskell) optimizedto handle natural language

• Resource Grammar Library implementing common morphologicaland syntactic structures

• Mildly context sensitive

• Bidirectional translations: concrete language ⇔ abstract syntax


GF grammars and translations

GF grammars consist of:

• One language-neutral abstract syntax

• Concrete syntaxes specify words, agreement, word order, etc. byimplementing the abstract categories and functions

Example

border : Country -> Country -> Relation

English: border x y = x!Nom + "borders" + y!Nom

Estonian: border x y = x!Gen + "naaber on" + y!Nom

GF translations consist of:

• First, parse a string in the original language to a tree (or trees)in the abstract syntax

• Then, linearize these trees as strings in the target language


Multilingual AceWiki: Screenshot


Multilingual AceWiki: Demo

http://attempto.ifi.uzh.ch/acewiki-gf/



ACE-in-GF

• Multiple controlled versions of natural languages that map toACE (and to each other)

• As a result, they can be bidirectionally mapped to various formallanguages already supported by ACE


ACE-in-GF: Example

German: Jedes Land, das nicht an ein Meer grenzt, ist einBinnenland.

ACE-in-GF tree:baseText (sText (s (vpS (everyNP (relCN (cn_as_VarCN country_CN)

(neg_predRS which_RP (v2VP border_V2 (thereNP_as_NP

(aNP (cn_as_VarCN sea_CN))))))) (npVP (thereNP_as_NP

(aNP (cn_as_VarCN landlocked_country_CN)))))))

ACE: Every country that does not border a sea is alandlocked-country.

OWL:SubClassOf(


:country

ObjectComplementOf(

ObjectSomeValuesFrom( :border :sea )

)

)

:landlocked-country

)Tobias Kuhn, ETH Zurich A Multilingual Semantic Wiki 19 / 27

ACE-in-GF: Implementation

Implementation of the ACE syntax:

• Targeting the subset of ACE that can be mapped to OWL

• Almost 100% coverage at almost 0% ambiguity

Support of most RGL languages:

• Bulgarian, Catalan, Chinese, Danish, Dutch, English, Finnish,French, German, Greek, Hindi, Italian, Latvian, Norwegian,Polish, Romanian, Russian, Spanish, Swedish, Thai, Urdu

• RGL-based design provides automatic increase in quality andlanguage-coverage over time

Status

• Some precision problems, e.g. with anaphoric references

• Ambiguity and coverage problems in some languages


Evaluation of AceWiki-GF

Hypothesis: A group of users reaches almost the same level of agreement

on the content of an article presented to them in different languages as

when the article is presented to all of them in the same language.

Design

• Based on a 500-word lexicon on European geography in threelanguages: English, German and Spanish

• 30 participants accessed AceWiki-GF and wrote sentences intheir language (10 participants for each language)

• They had to enter true and false sentences and tag them as such

• In a post-editing task, each participant checked the output oftwo other participants: one translated from another languageand one written in the same language (true/false tags wereremoved and sentences shuffled); they were asked to remove allfalse sentences


Evaluation of AceWiki-GF: Results

30 participants spent on average 37 minutes using AceWiki-GF,creating 316 sentences in total.

Definition of agreement level: (Tk + Fd)/SS is the total number of sentences, Tk the number of sentences marked as true

and kept, and Fd the ones marked as false and deleted

Agreement level (difference is not significant):

82.2%without translation

84.0%with translation

0% 25% 50% 75% 100%agreement level


Evaluation of AceWiki-GF: Results

Assumption: Translation introduces a constant translation error rate rthat has the effect of reducing the agreement level a to (1− r) · a.

New hypothesis: The translation error rate is less than 5%.

78.1%with hypothetical translation (r = 5%)

84.0%with translation

0% 25% 50% 75% 100%agreement level

p-value with one-tailed Wilcoxon signed-rank test: 0.046

→ With AceWiki-GF, translation error rate is less than 5%


Evaluation of AceWiki-GF: Feedback

Questionnaire for the participants contained these questions:

1 Was AceWiki Geography easy or difficult to use in general?

2 Was the sentence editor easy or difficult to use?

3 Was creating true and false statements easy or difficult toperform?

Possible answers: “very difficult” (0), “difficult” (1), “medium” (2),“easy” (3), and “very easy” (4)

Results:

1 Average: 2.93 (∼“easy”)




The Future...?

Can we make a truly multilingual Wikipedia?

• Store main content in a semantic representation

• Verbalization in different languages

• All content is instantly available in all languages (once therequired vocabulary is defined)

• Breaking the current dominance of English and putting an endto the lock-out of users speaking less widespread orunderrepresented languages

• Contributing to the Semantic Web

Related:

• http://www.wikidata.org

• http://meta.wikimedia.org/wiki/A_proposal_towards_a_

multilingual_Wikipedia


http://www.wikidata.org

http://meta.wikimedia.org/wiki/A_proposal_towards_a_multilingual_Wikipedia

http://meta.wikimedia.org/wiki/A_proposal_towards_a_multilingual_Wikipedia

Links

ACE parser (APE) source code: https://github.com/Attempto/APE

ACE-in-GF source code: http://github.com/Attempto/ACE-in-GF

AceWiki and AceWikiGF

• Source code: http://github.com/AceWiki/AceWiki

• Demos (non-GF): http://attempto.ifi.uzh.ch/acewiki/

• Demos (GF): http://attempto.ifi.uzh.ch/acewiki-gf/

MOLTO project web site: http://www.molto-project.eu

Attempto web site: http://attempto.ifi.uzh.ch

GF: http://www.grammaticalframework.org


https://github.com/Attempto/APE

http://github.com/Attempto/ACE-in-GF

http://github.com/AceWiki/AceWiki



http://www.molto-project.eu

http://attempto.ifi.uzh.ch

http://www.grammaticalframework.org

Thank you for your Attention!

If you are interested in Controlled Natural Languages,come visit us at CNL 2014!

CNL2014

Fourth Workshop on Controlled Natural Language

20–22 August 2014, Galwayhttp://attempto.ifi.uzh.ch/site/cnl2014/


http://attempto.ifi.uzh.ch/site/cnl2014/

a multilingual semantic wiki based on controlled natural language

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