1,721,054 research outputs found
Design and Implementation of a NetLogo Interface for the Stand-Alone FYPA System
No full textFYPA (Find Your Path, Agent!) is a multiagent system currently used by Ansaldo STS for off-line daily computation of paths of trains inside stations. Its exploitation for on-line replanning in case of unavailability of resources is envisaged in the very near future, since the system's performances demonstrated to be suitable for real time usage. In this paper we present StandaFYPA, the stand-alone version of FYPA that we developed for running batteries of tests on our own, without needing to access existing Ansaldo applications. StandaFYPA is equipped with a graphical interface implemented in NetLogo for off-line visualization, that we describe here in details
A correspondence repair algorithm based on word sense disambiguation and upper ontologies
No full textIn an ideal world, an ontology matching algorithm should return all the correct correspondences (it should be complete) and should return no wrong correspondences (it should be correct). In the real world, no implemented ontology matching algorithm is both correct and complete. For this reason, repairing wrong correspondences in an ontology alignment is a very pressing need to obtain more accurate alignments. This paper discusses an automatic correspondence repair method that exploits both upper ontologies to provide informative context to concepts c ∈ o and c′ ∈ o′ belonging to an alignment a, and a context-based word sense disambiguation algorithm to assign c and c′ their correct meaning. This meaning is used to decide whether c and c′ are related, and to either keep or discard the correspondence ∈ a, namely, to repair a. The experiments carried on are presented and the obtained results are provided. The advantages of the approach we propose are confirmed by a total average gain of 11,5% in precision for the alignments repaired against a 2% total average erro
Multi Agent Resource Allocation: a Comparison of Five Negotiation Protocols
No full textThis paper describes five systems that exploit negotiation strategies to solve multiagent resource allocation problems. A deep comparison is drawn among them according to different criteria that involve general features of the systems; adherence to widely accepted agent definitions; domain, purpose, and approach; analysis, design and implementation of the negotiation protocol. Considerations on how extending one of the analyzed systems in order to move a concrete step towards the realization of an integrated platform for developing negotiation protocols are also provided in the conclusions
Logical judges challenge human judges on the strange case of B.C.-Valjean
No full textOn May 12th, 2020, during the course entitled Artificial Intelligence and Jurisdiction Practice organized by the Italian School of Magistracy, more than 70 magistrates followed our demonstration of a Prolog logical judge reasoning on an armed robbery case. Although the implemented logical judge is just an exercise of knowledge representation and simple deductive reasoning, a practical demonstration of an automated reasoning tool to such a large audience of potential end-users represents a first and unique attempt in Italy and, to the best of our knowledge, in the international panorama. In this paper we present the case addressed by the logical judge - a real case already addressed by a human judge in 2015 - and the feedback on the demonstration collected from the attendees
Automatic ontology matching via upper ontologies: A systematic evaluation
No full textOntology matching is the process of finding correspondences between entities belonging to different ontologies. This paper describes a set of algorithms that exploit upper ontologies as semantic bridges in the ontology matching process and presents a systematic analysis of the relationships among features of matched ontologies (number of simple and composite concepts, stems, concepts at the top level, common English suffixes and prefixes, and ontology depth), matching algorithms, used upper ontologies, and experiment results. This analysis allowed us to state under which circumstances the exploitation of upper ontologies gives significant advantages with respect to traditional approaches that do no use them. We run experiments with SUMO-OWL (a restricted version of SUMO), OpenCyc, and DOLCE. The experiments demonstrate that when our structural matching method via upper ontology uses an upper ontology large enough (OpenCyc, SUMO-OWL), the recall is significantly improved while preserving the precision obtained without upper ontologies. Instead, our nonstructural matching method via OpenCyc and SUMO-OWL improves the precision and maintains the recall. The mixed method that combines the results of structural alignment without using upper ontologies and structural alignment via upper ontologies improves the recall and maintains the F-measure independently of the used upper ontology
OntoScene, a logic-based scene interpreter: implementation and application in the rock art domain
Full text linkWe present OntoScene, a framework aimed at understanding the semantics of visual scenes starting from the semantics of their elements and the spatial relations holding between them. OntoScene exploits ontologies for representing knowledge and Prolog for specifying the interpretation rules that domain experts may adopt, and for implementing the SceneInterpreter engine. Ontologies allow the designer to formalize the domain in a reusable way and make the system modular and interoperable with existing multiagent systems, while Prolog provides a solid basis to define complex rules of interpretation in a way that can be affordable even for people with no background in Computational Logics. The domain selected for experimenting OntoScene is that of prehistoric rock art, which provides us with a fascinating and challenging testbed
Exploiting Probabilistic Trace Expressions for Decentralized Runtime Verification with Gaps
Full text linkMultiagent Systems (MASs) are distributed systems composed by autonomous, reactive, proactive, heterogeneous communicating entities. In order to dynamically verify the behavior of such complex systems, a decentralized solution able to scale with the number of agents is necessary. When, for physical, infrastructural, or legal reasons, the monitor is not able to observe all the events emitted by the MAS, gaps are generated. In this paper we present a runtime verification decentralized approach to handle observation gaps in a MAS
Protocols with exceptions, timeouts, and handlers: A uniform framework for monitoring fail-uncontrolled and ambient intelligence systems
No full textThis paper describes an approach for designing, formalizing and implementing sentinels that detect errors in fail-uncontrolled multiagent systems, and controllers that identify particular situations in ambient intelligence (AmI) systems. The formalism we use for representing the expected patterns of actions along with exceptions, timeouts, and their handlers, is that of constrained global types extended with features for dealing with these new constructs. We provide the syntax and semantics of the extended constrained global types and examples of their use, in the different contexts of fail-uncontrolled and AmI systems
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