People

Research activity in 1999

Model based reasoning has been the main area of investigation of our group in recent years. Several aspects have been explored.

A lot of attention has been given to the temporal dimension in model-based diagnosis, especially as regards the adequacy of different forms of temporal diagnosis for different classes of temporal diagnostic problems. In particular, approaches to modeling and diagnosis of dynamic systems have been analyzed and compared.

Applications of model-based diagnosis have been developed in the BRITE-EURAM "Vehicle Model-Based Diagnosis" project. Particular attention has been given to the use of model-based diagnosis for on-board diagnosis of cars. Concrete results are the following: A diagnosis engine has been developed; it can solve diagnostic problems as single cases, and it is also able to generate off-line a decision tree suitable to be embedded on board, to fit time and space constraints of an embedded system. The "Common Rail" system for diesel engine fuel supply has been modeled in terms of qualitative deviation equations, and the above diagnosis engine has been used for that model to produce a decision tree. The system has been tested on a prototype car, a Lancia Kappa equipped with a 2.4 liters Common Rail diesel engine. The system receives signals (sensor readings) from the electronic control unit of the car and can determine the diagnosis and the recovery action to be performed. the system has been successfully tested on a set of real cases.

Model-based reasoning has been applied to another relevant domain for diagnostic problem solving. In a cooperative project supported by ASI (Agenzia Spaziale Italiana) we have developed the diagnostic module. In particular, we have investigated how to represent knowledge at different degrees of abstraction and we propose an innovative method for representing diagnoses in a concise way. In particular, the mechanism is based on a formulation of diagnosis in terms of constraints and variable assignment. Such a representation allows one to develop efficient methods also for diagnosis generation.

The domain chosen as test-bed is the space robotic arm SPIDER and a prototype of the diagnostic module for such a device has been developed .

Multi-modal reasoning

Since MBR is known to have high computational costs, the interest for combining MBR with other problem solving methods (potentially less expensive) has grown in the recent years. In particular we have investigated how to combine Case-based reasoning approach with MBR in order to speed-up diagnostic problem solving, and making it more practical also for large applications. During 1999 we performed an in-depth analysis of the performance of the ADAPtER system, an architecture for diagnostic problem solving based on the integration of CBR and MBR developed in previous years.

Interesting results have been obtained in the area of learning: innovative strategies have been developed that are able to decide automatically under which conditions new cases have to be learnt and stored in the case memory and when cases have to be forgotten (because non very useful for adaptation). In this way we have been able to automate the management of the case memory and ADAPtER is now able to improve its performance both in term of speed-up and competence by starting with an empty case memory. .

Temporal reasoning.

As regards temporal reasoning in itself, we extended LaTeR, a manager of temporal constraints we have developed since 1993, in order to deal with constraints on intersection, union and difference of time intervals, and with disjunctive temporal constraints. We also applied LaTeR to different areas, ranging from temporal diagnosis to the treatment of temporal constraints in relational databases.

Problem solving and Agents.

In the recent years we have experimented that the capability of problem solving in a particular task has to be integrated with other reasoning capabilities in other tasks. For example, diagnostic problem solving could be integrated with monitoring and planning. Configuration should be combined with presentation.

For this reason we have started to investigate how a particular problem solving activity could be represented as an intelligent agent. Some initial work has been done in the area of configuration and diagnosis. The notion of intelligent agent find interesting application also in the context of data mining and in the field of the analysis of large volume of data. In particular, they are studied for the extraction of the statistical dependencies among data. The representation of the dependency relationships between objects makes use of the ``dependence values'', a new, condensed and powerful form to represent the event of non independence of a set of objects.

Part of the work described above has been developed in co-operation with colleagues of the Dipartimento di Scienze e Tecnologie Avanzate, Universita’del Piemonte Orientale, in particular Prof. Paolo Terenziani, Dr. Luigi Portinale and Dr. Daniele Theseider Dupre’.

1999 Publications

Software Products

The research group was also active in the project devoted to intelligent agents co-ordinated at local level by Prof. Martelli and at national level by Prof. Turini.

Moreover, the group co-operated with other members of the Department to the research activity carried on in the CANTIERE MULTIMEDIALE "Servizi telematici adattativi" sponsored by TELECOM Italia.

Activity and role in the scientific community

• Member of the Executive Board of European Network of Excellence MONET


• Chairman of the Infrastructure Planning Committed of the MONET Network


• Member of the program committee of the AIME 99 (European Conference on Artificial Intelligence in Medicine) Alborg, 1999.


• Member of the program committee of the DX99, Int Workshop on Principles of Diagnosis, Loch Awe Scotland 1999


• Invited Speaker at the 16^th International Joint Conference on Artificial Intelligence (IJCAI 99), Stockholm 1999


• Invited speaker at CAEPIA '99: Iberic Conference on Artificial Intelligence, Murcia September 99

• Member of the Advisory Committee of the 16^th International Joint Conference on Artificial Intelligence


• President of the Italian Association for Artificial Intelligence


• Italian representative in the European Coordinated Committee for Artificial Intelligence


• Member of the Scientific Committee of “Sistemi Intelligenti” published by Il Mulino


• Member of the “Habilitation diriger des recherches en Informatique.” committee of Dr. Josette Pastor (Universite’de Rennes)

Oral presentations in Congresses and Conferences

• Model-based Diagnosis in the Real World: lessons learned and challenges remaining, invited talk at the 16th International Joint Conference on Artificial Intelligence (IJCAI 99)


• Model-based diagnosis: Theory and Applications, at CAEPIA '99


• On the application of personalization techniques to news servers on the WWW, at AI*IA 99

• Knowledge representation and reasoning for fault identification in a space robot arm, at the 5th Int. Symp. on Artificial Intelligence, Robotics and Automation in Space, Noordwijk, Holland, June 1999


• Diagnostic Agent for SPIDER, Workshop on Intelligent Systems for supervising autonomous spacecraft, Roma, March 1999.


• Invited Talk on Diagnostic Reasoning at AEI, Palermo March 1999.