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DIPARTIMENTO DI INFORMATICA |
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Research Report Year 2003
Computer Science
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Last and first name |
Position |
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Lesmo Leonardo |
Full Professor |
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Lombardo Vincenzo |
Associate Professor
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Boella Guido
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Researcher |
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Damiano Rossana |
Researcher |
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| Bosco Cristina |
Research Assistant |
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Mazzei Alessandro |
PhD Student |
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Sauro Luigi |
PhD Student |
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Radicioni Daniele Paolo |
PhD Student |
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Robaldo Livio |
PhD Student |
1. Syntactic analysis and robust methods for natural language processing.
2. Agent models.
3. Ontologies and Legal Knowledge
4. Computer music
1) Syntactic analysis and robust methods for natural language processing.
1.a -- Linguistic resources.
The linguistic resources currently available, most of which have
been extended and enhanced in 2003, on the basis of the approach developed
in the previous years, include the following:
- A morphological dictionary including about 23.000 word lemmas.
- A Treebank of 1800 Italian Sentences (approximately 50.000 words),
represented in a Dependency format. More information on the treebank
may be found at http://www.di.unito.it/~tutreeb/.
- A Robust Dependency Parser (including a morphological analyzer and
a Part-of-Speech Tagger). The parser has been tested on a corpus of
about 400.000 words. It analyzes about 120 word per second on a Pentium
4 processor under Linux in compiled LISP . The tests on the manually
corrected treebank revealed an error rate (in terms of wrong attachments
and wrong arc labels) of 16.7%. The parser also includes a preliminary
treatment of traces, adopted for preserving the projectivity of the
dependency trees.
1.b -- Psycholinguistic models of sentence processing.
Empirical psycholinguistic analyses show that incrementality is one important feature of human sentence processing. In particular, humans perform a directional analysis of the language, obtaining an incremental interpretation of sentences. From an applicative point of view, incrementality is important also for language modeling, a key sub-task for speech recognition systems. In this year, in cooperation with the psycholinguistic group of the Glasgow University, we designed and performed experiments to confirm the strong incremental hypothesis. This hypothesis regards the fully connectivity of the data structure used by the language processor in the sentence analyses.
1.c -- Formal methods for the representation of syntactic knowledge.
Taking in account the results of the experiment mentioned above,
we refined the definition of the DV-TAG formalism. Lexicalized Tree
Adjoining Grammars (L-TAG) is a well studied formalism that has several
advantages with respect to the context-free grammars in the representation
of syntactic knowledge about natural languages. In particular, the
"extended domain of locality" allows a simple description
of several linguistic phenomena, as the presence of traces and sub-categorization
frames for the verbs in the analysis. Dynamic Version of L-LTAG (DV-TAG)
is a formalism defined with the aim of augmenting L-TAG, by following
the suggestions coming from the incrementality hypothesis.
We refined the definition of DV-TAG through the formalization of the
dependency tree structure, a data structure that is in some way similar
to the derivation tree of L-TAG but in other way similar to the analysis
derived by a dependency grammar. Using this feature we were able to
derive some difficult linguistic analyses, as the ones required for
sentences with raising and bridge verbs, that standard L-TAG is not
able to correctly describe. Apart from this, we begin the formalization
of a polynomial parser for DV-TAG using the paradigm of the dynamic
grammars. In particular we use an Earley-style strategy modified to
take in account strong incrementality.
Another line of research regarding L-TAG concerns the automatic extraction
of a grammar from a linguistically annotated corpus. In particular,
we designed a new extraction algorithm with the aim to exploit the
information carried by the dependency annotation of the TUT corpus.
2) Agent models
During year 2003, the research about autonomous agents theory focused
on the formalization of normative multiagent systems and proceeded
with the development and evaluation of planning strategies for agents
who react to the changes in their environment.
For what concerns the formalization of normative multiagent systems
we proposed to model normative systems using the agent metaphor: the
normative system, even if it is a social entity, is described by attributing
to it mental attitudes like beliefs, desires and intentions. In this
way norms can be modelled as goals of the normative systems associated
with the subgoals of considering as a violation any behavior not consistent
with the norm and of sanctioning violations. The research includes
modeling the reasoning process of an agent who is subject to norms;
this is accomplished by making the agent foresee whether it will be
sanctioned or not; in turn, this is obtained by recursively modeling
the decision taken by the normative system considered as an agent.
Further topics are the definition of permissions as exceptions to
obligations, the structuring of the normative systems with roles,
and the application of the agent metaphor to virtual communities and
groups. This work is made in cooperation with the CWI research institute
of Amsterdam.
The second line of research on agents concern planning strategies
for dealing with the problem of updating the current intentions of
an agent to face a new situation which occurred. We used as a basis
of the research a decision theoretic hierarchical planner. The replanning
process proceeds by making the plan found by the planner more partial
and then refining it again without restarting the planning process
by first principles. After the implementation of such algorithm, we
made an evaluation phase to compare the performance of the replanning
strategy with respect to the performance of a planner which has to
build an entire new plan. The evaluation confirmed the prediction
that our incremental replanning algorithm performs better than the
corresponding planning algorithm when dealing with a failure.
3) Ontologies and Legal Knowledge
The activity on ontologies has been carried out in cooperation with
the Department of Scienze Giuridiche of the University of Torino.
The activity of the NLP group has mainly been concerned with the development
of an ontological model of norms and obligation, with special attention
to its connections to BDI models. In this context, norms are seen
as constraints on the activity of agents, that they take into account
when they determine their intentions on the basis of their beliefs,
desires, and goals (planning). This is obtained by modeling the rationality
of agents subject to the norms in terms of utility functions; the
presence of a norm prohibiting a given action or a given state affects
the utility of the plans including that action or leading to that
state, so that an alternative line of behaviour may be chosen. The
reduction of the utility value is obtained by associating a sanction
with the norms, which affects the utility in a negative way. An analogous
approach can be applied for modeling rewards instead of sanctions.
The study of some specific legal concepts (goods and fruits) has been
extended and the associated ontological analysis has been integrated
within a philosophically well-founded ontological framework (DOLCE,
developed mainly by the Laboratory for Applied Ontology - ISTC-CNR,
Trento, within the European project WonderWeb).
This research is being carried out also in partial cooperation with
the Special Interest Group on Legal Ontologies of the European Network
OntoWeb, in particular with groups located in Roma and Trento.
4) Computer Music
4.a -- Music performance
The goal of this area is the development of cognitive models for music
performance. In particular we focus in the fingering problem, a difficult
task in the case of string instrument, where the same note can be
played on several positions. Fingering is an essential component of
sound production, since the character of a piece is the result of
the interaction between the musician and the instrument. Our experiments
rely on a physical model of the classical guitar, and we compare the
predictions of the model with the performances of human experts on
the same piece.
4.b -- Algorithmic composition
In this area we explore the possibility of automating some aspects
of the composition process with a formal model. In particular, we
focus on the composition process with granular synthesis, a technique
that extends the notion of music events from the standard note approach
to the grain level of a sound waveform. We have proposed a two-level
method for the representation of a music composition based on a graph
navigation.
· Francesca Biral, Vincenzo Lombardo, Rossana Damiano, Antonio
Pizzo, Cyrano goes to Hollywood: a drama-based metaphor for information
presentation, Atti del Fourth Workshop Artificial Intelligence in
Mobile Systems (AIMS 2003), Seattle, 2003.
· Cristina Bosco and Carla Bazzanella: Corpus linguistics and
the modal shift in Old and Present-Day Italian: temporal pragmatic
markers and the case of 'allora'. In C. Push (editor), Procs. of the
2nd Freiburg Workshop on Romance Corpus Linguistics – Corpora and
historical linguistics, Freiburg im Breisgau, Germany, Draft, 2003.
· Guido Boella and Rossana Damiano: Empirical evaluation of
a replanning algorithm. In Procs. of ICAPS Workshop on plan execution,
2003. (PostScript)
· Guido Boella and Leendert van der Torre: Access control in
virtual communities: Prohibition, permission, authorization and delegation
of power in the grid. In Procs. of Knowledge Grid and Grid Intelligence
workshop at WI/IAT'03 (KGGI'03), 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Attributing mental
attitudes to normative systems. In Procs. of AAMAS'03, Melbourne,
2003. ACM Press. (PostScript)
· Guido Boella and Leendert van der Torre: Attributing mental
attitudes to groups: Cooperation in a qualitative game theory. In
Procs. of Collaboration Agents: Autonomous Agents for Collaborative
Environments at WI/IAT'03 (COLA'03), 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Bdi and boid argumentation:
Some examples and ideas for formalization. In Procs. of IJCAI Workshop
on Computational Models of Natural Argument, Acapulco, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Decentralized control:
Obligations and permissions in virtual communities of agents. In Procs.
of ISMIS, Maebashi, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Division of powers
in MAS control. In Procs. of AAMAS Workshop on Autonomy, Delegation
and Control, Melbourne, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Game specification
in the trias politica. In Procs. of BNAIC'03, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Local policies for
the control of virtual communities. In Procs. of IEEE/WIC Web Intelligence
Conference, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Norm governed multiagent
systems: The delegation of control to autonomous agents. In Procs.
of IEEE/WIC IAT Conference, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Obligations and
permissions as mental entities. In Procs. of IJCAI Workshop on Cognitive
Modeling of Agents and Multi-Agent Interactions, Acapulco, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Obligations as social
constructs. In Procs. of the AI*IA Conference, Pisa (Italy), 2003.
(PostScript)
· Guido Boella and Leendert van der Torre: Permissions and
obligations in hierarchical normative systems. In Procs. of ICAIL
03, pages 109-118, Edimburgh, 2003. ACM Press. (PostScript)
· Guido Boella and Leendert van der Torre: Permissions and
undercutters. In Procs. of IJCAI Workshop on Non Monotonic Reasoning,
Actions and Causality, Acapulco, 2003. (PostScript)
· Guido Boella and Leendert van der Torre: Policy management
for virtual communities of agents. In Procs. of WOA'03 Workshop, 2003.
(PostScript)
· Guido Boella and Leendert van der Torre: Rational norm creation.
In Procs. of ICAIL 03, pp. 81-82, Edimburgh, 2003. ACM Press. (PostScript)
· Guido Boella and Leendert van der Torre: Your wish is my
command: Sanction-based obligations in a qualitative decision theory.
Draft, 2003. (PostScript)
· Cristina Bosco and Vincenzo Lombardo: A relation-based schema
for treebank annotation. In A. Cappelli, F. Turini (eds.) Advances
in Artificial Intelligence – LNCS 2829, Springer Verlag, Berlin, 2003,
462-473.
· Fabrizio Costa, Paolo Frasconi, Vincenzo Lombardo, Giovanni
Soda: Towards Incremental Parsing of Natural Language using Recursive
Neural Networks, Applied Intelligence 19 (1-2), 2003, 9-25.
· Rossana Damiano, Vincenzo Lombardo, Francesca Biral, Antonio
Pizzo: Cyrano: a character-centered architecture for interactive presentations,
Atti del Simposio Human-Computer Interaction in Italy (HCI-Italy),
Torino, 2003.
· Alessandro Mazzei: Formalizing a constituency based dynamic
grammar. In Balder Ten Cate, editor, Proc. of the Eighth ESSLLI Student
Session, Vienna, 2003, 181-190.
· Daniele Radicioni and Vincenzo Lombardo: Computational modeling
of chord shapes in guitar fingering, Proceedings of the 3rd International
Workshop on Gestural Analysis (GW2003), Genova, 2003.
· Patrick Sturt, Fabrizio Costa, Vincenzo Lombardo, Paolo Frasconi,
Learning structural first-pass attachment preferences with dynamic
grammars and recursive neural networks, Cognition 88, 2003, 133-169.
· Patrick Sturt and Vincenzo Lombardo: Grammatical theory and
incremental processing, Atti della 16th CUNY Conference on Sentence
Processing, 2003.
· Andrea Valle and Vincenzo Lombardo: A two-level method to
control granular synthesis, Proceedings of the 14th Colloquium on
Musical Informatics (CIM 2003), Firenze, 2003, 136-140.
Dependency Parser
Downloadable from the NLP Group site.
Tested under Linux on Allegro Common LISP and CLISP.
Including the Italian morphological dictionary, the morphological
analyzer, the POS tagger, various documents and user manual
Ref. Leonardo Lesmo
(Project of Relevant National Interest - COFIN 2003 - two years: 2003-2004)
Titolo: Tecnologie informatiche per il supporto allo sviluppo di tassonomie ed ontologie giuridiche (Computer Science for Supporting the Development of Legal Taxonomies and Ontologies)
Responsabile Scientifico (Scientific Responsible): Leonardo Lesmo
Coordinatore Scientifico a livello Nazionale (National Coordinator): Gianmaria Ajani, Dipartimento di Scienze Giuridiche, Università di Torino
Finanziato da (funded by): MIUR
Finanziamento Totale (Total Grant): 22.600 Euro
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Last update:
May 05, 2004
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