Some Foundational Linguistic Elements for QA

Systems: an Application

to E-government Services

Farida Aouladomar

JURIX 05

9/11/05

Objective problematics of procedural texts for

answering procedural questions on the web governments increasingly offer online services

to their citizens. ex: How can I get the french citizenship?

Semantics and structure of procedural text answers to procedural questions are structures where to unify questions and parts of the

procedural texts give a complete and appropriate response

Advanced Question – Answering

Framework

QA Systems for factoid questions : InferenceWEB (McGuinness, 04), JAVELIN (Nyberg and al, 03), Mulder (Kwok and al, 00), WEBCOOP (Benamara, 04)

Non-factoid questions: comparison, procedural, opinion, causal, etc.

How-questions within a cooperative environment

How to get a passport ?

Response

Question analysis

Procedural Question?

Search engine

n texts

Filtering 1

Procedural texts ?

Annotation

Grammar

Filtering 2

Unification

Overview

Procedural questions

Grammar of procedural discourse - syntactic structure

- linguistic marks

Questionability and responses

Procedural questions (1)

Procedural questions = questions

introduced by « comment » - Comment vas-tu ?

- Comment dit-on maison en espagnol ?

- Comment est mort John?

- Comment on mange le couscous au Maroc ?

- Comment payer mon billet d’avion ?

- Comment changer une roue ?

- Comment créer une entreprise ?

Procedural questions (2)

Other forms of procedural questions :

– Forms in : « que faire … », « quel + être + proposition » …

Ex: que faire pour obtenir un visa ?, quelles sont les démarches à effectuer pour obtenir un visa pour l’Inde?quelle est la procédure pour obtenir la nationalité belge ?

– The elliptical use of « comment » : key words

Ex: trouver un avocat, déposer une plainte, inscription sur liste électorale …

– Lexical inference : Ex : j’ai perdu mon passeport

Questions expecting an answer of procedural type :

Ex: est-il possible d’avoir la double nationalité ?

Procedural questions (3)

Overview

Procedural questions

Grammar of procedural discourse

- syntactic structure

- linguistic marks

Questionability and responses

Sequences of instructions operating over a specific set of entities in order to reach a goal.

Goals & subgoals = skeletal structure of procedural texts

Group of texts : cooking receipes, maintenance manuals, assembly notices, directions for use, teaching texts, medical notices, social behavior recommendations, advice texts, savoir-faire guides, itinerary guides, architectory plans, musical scales, legislation, court decisions,legal guidelines & procedures, etc.

Corpus : identify textual elements of procedural texts for the answer process.

Procedural texts

Discursive Structure - Corpus (1) Structure analysis of procedural texts :

- Corpora analysis : method based on “how” queries on the web and on manual enrichment

Questions classificationQuestions classification Nb of procedural texts Nb of procedural texts from queries inventoryfrom queries inventory

Nb of added Nb of added procedural textsprocedural texts

Total number of Total number of texts in our corpustexts in our corpus

Communication / Communication / advices / advices / e-governmente-government

48 0 48

Technical domain Technical domain computer science computer science assembly textsassembly texts

30 20 50

HealthHealth 3 6 9

ReceipesReceipes 0 10 10

RulesRules 0 7 7

totaltotal 81 43 124

Discursive StructureGrammar (2)

Text → title, (summary), (warning)+, (pre-requisites)+, (picture) + < objective.

Summary → title+.

Pre-requisites → list of objects, (instruction sequences).

Instruction sequences → instseq < {connector} < instruction sequences / instseq.

Objective → {goal}< (warning), (picture), (pre-requisites), instruction sequences+ / objective

Grammar (3)

Imperative linear sequence → instruction < {temporal mark}, imperative linear sequence / instruction.

Optional sequence → optionality expression, imperative linear sequence.

Instruction sequence → imperative linear sequence / optional sequence / alternative sequence / imperative co-temporal sequence.

Imperative co-temporal sequence → imperative linear sequence < co-temporal mark < imperative co-temporal sequence / instruction.

Instruction → (iterative expression), action, (goal) (argument)+, (reference), (picture)+, (warning)

Alternative sequence → (conditional expression), (argument), imperative linear sequence, (alternative-opposition mark) < instseq / (conditional expression, instseq).

Grammar (3)

summary

title

Texte → title, (summary), (warning)+, (pre-requisites)+, (picture) + < objective.

warning

Objective

Objective → {goal}< (warning)+, (picture)+, (pre-requisites), instruction sequences+ / objective

goal

warning

Instruction sequences

Pre-requisites

Imperative linear sequence → instruction < (temporal mark) < imperative linear sequence / instruction

La premiere étape consiste à ouvrir entièrement le boîtier,

puis de le placer à plat sur une surface large où vous aurez suffisamment de place pour travailler confortablement,

et enfin retirer tous les caches en plastiques des baies à l’avant du PC

The first stage consists in fully-opening the box,

then place it on a large surface where you will have sufficient place to

work comfortably,

and finally to withdraw the plastic protections on the PC front side.

Instruction → (iterative expression), action, (goal) (argument)+, (reference), (picture)+, (warning)

La première étape consiste à ouvrir entièrement le boîtier,

puis de le placer à plat sur une surface large où vous aurez suffisamment de place pour travailler confortablement,

et enfin retirer tous les caches en plastiques des baies à l’avant du PC

La premiere étape consiste à ouvrir entièrement le boîtier,

puis de le placer à plat sur une surface large où vous aurez suffisamment de place pour travailler confortablement,

et enfin retirer tous les caches en plastiques des baies à l’avant du PC

ArgumentTemporal marks Instructions

Texte → title, (summary), (warning)+, (pre-requisites)+, (picture) + < objective.

title

Pre-requisites

Objective

annotation < objective> <goal> Postez le formulaire et les documents au Centre

de traitement des demandes. <\goal>

< instseq> < imper_linear> <temp_mark> Après <\temp_mark> <instr> avoir rempli le formulaire de demande, <\instr> <instr> vous devez le poster, dans l’enveloppe-réponse fournie, à l’adresse suivante :

Centre de traitement des demandesCitoyenneté et Immigration CanadaC.P. 7000Sydney (Nouvelle-Écosse) B1P 6V6 <\instr> < imper_linear> < \instseq>

<warning> N’oubliez pas : de signer et de dater le formulaire ainsi que de signer vos photos; d’inclure le reçu du paiement (formulaire IMM 5401); de mettre votre demande dans l’enveloppe; de mettre les photos dans l’enveloppe; d’inclure les photocopies de tous les documents requis. <warning>

<\objective>

< instseq> < imper_linear> <temp_mark> Après <\temp_mark> <instr> avoir rempli le

formulaire de demande, <\instr> <instr> vous devez le poster, dans l’enveloppe-réponse fournie, à l’adresse suivante :

Centre de traitement des demandesCitoyenneté et Immigration CanadaC.P. 7000

Sydney (Nouvelle-Écosse) B1P 6V6 <\instr> <\imper_linear> < \instseq>

<warning> N’oubliez pas :<instr> de signer et de dater le formulaire ainsi que de signer vos photos <\instr>;

<instr> d’inclure le reçu du paiement (formulaire IMM 5401) <\instr> ; <instr> de mettre votre demande dans l’enveloppe <\instr>;

<instr> de mettre les photos dans l’enveloppe <\instr>;

<instr> d’inclure les photocopies de tous les documents requis. <\instr> <warning>

The grammar is :

-- too rigid, and not sufficient to describe all facets of procedural texts

-- not very constrained

-- not explicative and predictive enough

A new orientation of the discursive structure of procedural texts : principles and norms

Grammar limits

Overview

Procedural questions

Grammar of procedural discourse

- syntactic structure

- linguistic marks

Questionability and responses

Linguistic marks (1)

Discursive marks : allow for the identification of the elements of the grammar

-- classical temporal marks (precedence, overlap, inclusion, etc.)-- restrictions, conditions, alternatives, comparisons, etc. -- causal marks (identification of objectives, goals, warnings, preventions, consequences, etc.)

-- typoraphic criterion:

instruction localization (1)

-- morphological criterion (ex: imperatives)

instruction localization (2)

-- semantic criterion: action verbs

instruction localization (3)

Overview

Procedural questions

Grammar of procedural discourse

- syntactic structure

- linguistic marks

Questionability and responses

How to download music ?

Response

Question analysis

Procedural Question?

Search engine

n texts

Filtering 1

Procedural texts ?

Annotation

Grammar

Filtering 2

Unification

QUESTIONABILITY

Questionability (1)

The ability or the relevance of any text to respond to How-questions.

Stage 1: determine the « CATEG » rate

-- measure the procedural nature of a text

Stage 2: determine the « QUEST » rate

-- measure of zones which are qualified for potential question unification

Questionability (2)

Stage 1 : « CATEG » => 3 « surface criteria »

- typographic forms (TF)- morpho-syntactic marks (MSM)

- articulatory marks (AM) : (temporal, argumentative, etc.)

average frequency is computed for each criteria for all texts (noted as TFaverage, MSMaverage,

AMaverage)

Questionability (3)

For text i, we Define its CATEG rate:

Selection of the « best » texts => annotation

Questionability (4)

Stage 2 : « Quest » => evaluate the number of areas which can potentially match with How-questions

4 areas leading to 4 criteria : - number of titles (TIT)- action verbs (AV)- number of goals (GOA)- manners (MAN)

Questionability (5)

For text i, we define its QUEST rate  :

Question Unification

Responses

3 tasks :

-- selecting procedural texts which have the best questionabilty rate

-- matching the question body with « questionable zones »

-- extracting the relevant portion of the text and returning it to the user in a user-friendly way

To Conclude … Still experimental work

- ongoing : design of a system that annotates texts and evaluates the questionability rate

Perspectives :- validation / evaluation

- unification give a complete answer to the user

- respond cooperatively to procedural questions

Work more specifically on the structure of legal / administrative procedural texts