1,720,967 research outputs found
Approcci basati su agenti e semantica per lo sviluppo di infrastrutture per scenari intelligenti
No full textL'attività di ricerca presentata in questo lavoro copre due diversi argomenti: approcci basati sulla semantica e sugli agenti per sviluppare infrastrutture per scenari intelligenti. Il primo argomento riguarda i motori di ricerca basati sulle parole-chiave e il secondo sistemi multi-agente per la gestione delle emergenze territoriale.
Le interrogazioni basate su parole-chiave su database relazionali offrono una ottima alternativa al tradizionale SQL, specialmente quando si ha a che fare con schemi aventi viste grandi, complessi e non noti. La vera sfida e quella di modellare l'associazione delle parole-chiave, che fanno dell'interrogazione, con alcuni elementi della struttura del database. Gli approcci attuali usano tecniche di “information retrieval” su insiemi di dati precedentemente raccolti e indicizzati. Questa tecnica o limita l'utilizzo dei motori di ricerca in molti scenari applicativi, incluso i sistemi informativi di integrazione, nelle quali l'istanza non è direttamente disponibile per costruire gli indici necessari. Per questo motivo è stato proposto un nuovo approccio che sfrutta solo informazioni sui dati ed impiega una serie di informazioni ausiliarie per la conversione delle parole-chiave in una espressione SQL significativa. Le meta-informazioni vengono estratte dai DBMS ed arricchite da operatori oppure con strumenti automatici sfruttando ontologie note come WordNet. La novità sta nella modo in cui ogni parola-chiave viene mappata ad un elemento dello schema relazionale. Alla base di questa tecnica vi è una versione modificata dell'algoritmo Hungarian che riduce notevolmente il numero delle interpretazioni da considerare. Per ogni interpretazione vengono costruiti i possibili percorsi che connettono gli elementi relazionali e per ogni percorso il codice SQL per l'accesso ai dati. Un prototipo munito di interfaccia grafica è stato sviluppato per effettuare i test ed illustrare le valutazioni sulla efficienza ed efficacia.
Il secondo argomento di ricerca riguarda il coordinamento e la cooperazione durante le emergenze territoriali mediante la tecnologia multi-agente. La gestione dell'emergenza territoriale è una delle attività più critiche nel sistema sanitario. In questo scenario, è necessario un tempo di risposta molto veloce per ridurre i danni alle persone e poter salvare più vite possibili. La complessità delle operazioni richiede coordinamento, cooperazione e capacità decisionali. Molti sono gli attori in questo scenario, come personale medico e paramedico, vigili del fuoco e forze di polizia. Tutti questi attori devono cooperare e collaborare per raggiungere i loro obiettivi. Per soddisfare questi requisiti è stata utilizzata la tecnologia multi-agente ed in particolare la piattaforma JADE. La nuova architettura, chiamata Ubimedic2 (un estensione di Ubimedic), fornisce una sistema P2P gestito dagli Agenti le quali autonomamente scambiano le informazioni necessarie ed organizzano le operazioni di soccorso. Questo approccio e nuovo e non è stato adottato precedentemente nell'ambito delle emergenze territoriali. Gli agenti scambiano informazioni mediante messaggi FIPA ed organizzano le operazioni basandosi sul modello DBI (Belief-Desire-Intention). Ogni componente dell'architettura è stato sviluppato con le funzionalità che deve mettere a disposizione. Basandosi sull'architettura disegnata, è stato sviluppato un framework in Java con una serie di interfacce per poter simulare scenari reali. Inoltre, sono state sviluppate due applicazioni per smart-phone per effettuare test su dispositivi reali. Infine, è stata fatta l'integrazione con la tecnologia PIM per migliorare il processo di coordinamento tra gli agenti riducendo il numero dei messaggi scambiati e compattando il codice usando la mobilità forte del codice.The research activity presented in this work covers two different topics: semantic- and agent-based approaches to develop infrastructures for intelligent scenarios. The first topic covers the keyword-based search engines and the second, multi-agent systems for disaster management.
Keyword queries over relational databases offer a convenient alternative to traditional SQL, especially in case of large, complex or unknown schemas. The challenge in answering a keyword query over a relational database is to find in what database structures the items described by the keywords are modelled, and how these structures relate to each other. Current approaches apply information retrieval technique to collections of data previously gathered and indexed. This technique limits the use of these search engines in many interesting application scenarios, including information integration systems, in which the instance data is not directly available for building the required indexes. For this reason, the research activity was addressed to develop a new approach exploiting only meta-data information of the data sources, and using a set of auxiliary information to convert keyword queries into semantically meaningful SQL expressions. The meta-information are extracted from the DBMS and enriched by an human operator or exploiting by ontologies such as WordNet. The novelty of this approach lays on the way each keyword is mapped to a schema element (such as table and attribute) or to a value (attribute domain). The core of this technique is an extended version of the Hungarian algorithm which significantly reduces the number of possible keyword interpretations that need to be considered. For each interpretation, the set of possible path connections are discovered using graph techniques. For each path the SQL query string is build, executed and data retrieved and sent to the user. To perform tests on this new approach, a graphical user interface prototype has been implemented. Finally, a set of experimental evaluations illustrates its efficiency and effectiveness.
The other topic faced during the research activity is the coordination and the cooperation in territorial management scenarios using the multi-agent technology. Territorial emergencies and large-scale disasters are one of the most critic activities in healthcare systems. In such scenarios, a very quick response is necessary in order to reduce the serious damage of people health involved in disasters and to safe as many lives as possible. The criticality of the situation needs a very fast response, coordination, cooperation and decision making. Many are the actors in these scenarios such as medical staff, firemen and policemen. All these actors must cooperate and coordinate in order to reach their target. Decision making must be fast and accurate. To face such requirement the multi-agent technology has been employed and in particular the JADE platform. The architecture designed, called Ubimedic2 (an extension of Ubimedic), provide a P2P system managed by agents that autonomously exchange the necessary information and organize the rescue operation. This approach is novel and has not been previously faces in the disaster management scenarios. Agents share information using FIPA compliant messages and organize the operations based on the BDI (Belief-Desire-Intention) model. Each component of the architecture has been implemented with the main functionality it must provide. Based on the architectural design, the framework has been developed in Java and a GUI prototype is used to simulate real case studies. Moreover, two applications for smart-phones have been developed to perform tests on real devices and evaluate the feasibility of the approach. Finally the integration with the PIM technology has been done in order to improve the coordination process among agents, reducing the number of messages exchanged and exploiting the strong mobility to compact the coordination logic in a single process
Coordination Issues in an Agent-Based Approach for Territorial Emergence Management
No full textThis paper presents a new architectural approachfor managing the health-care emergences and large scaledisasters using agent-based applications. Such scenarios requirea support that must be distributed, context-aware, reactive andautonomous. In the following we will show how agent’s behaviourbest fits to these requirements and how the technologycan be applied efficiently to problems where the main challengeis the coordination and collaboration between components. Wepropose a FIPA compliant Multi-Agent System based on theBDI and PIM technology
Managing territorial emergencies with Ubimedic2
No full textWe propose Ubimedic2, an agent based frame-work that enables the implementation of Multi-Agent Systemsfor emergency management and territorial disasters. In thisdemo we present a simple simulation to better expose theUbimedic2 functionalities
Ubimedic2: An Agent-Based Approach in Territorial Emergence Management
No full textHealthcare emergences and large scale disastersare two of the most critic scenarios of healthcare system.Such scenarios require a support that must be distributed,context-aware, reactive and autonomous. This paper presentsan architectural approach for coordination based on the multiagenttechnology. In the following, we will show how agentsbehaviour best fits to these requirements and how can beefficiently applied to these problems. In this paper we propose aframework, called Ubimedic2, that enables the implementationof Multi-Agent Systems for emergency management. Theframework is FIPA compliant and based on the BDI technology.Healthcare emergencies and large scale disasters are two of the most critic scenarios of the healthcare system. Such scenarios require a support that must be distributed, context-aware, reactive and autonomous. This paper presents an architectural approach for coordination based on the multi-agent technology. In the following, we will show how agents behaviour well fits these requirements and how can be efficiently applied to these problems. In this paper we propose a framework, called Ubimedic2, which enables the implementation of Multi-Agent Systems for emergency scenarios management. The framework is FIPA compliant and it is based on the BDI technology. © 2011 ICST
Designing and implementing intelligent agents for e-health
No full textRecent large-scale disasters and territorial emergences,such as the Japan seaquake and Australian inundation,has bring to the attention to the efficiency of the rescueoperation. Such scenarios are unpredictable and require aprompt and coordinated reaction from the authorities. Thispaper presents an architectural approach for coordinationand cooperation based on the Multi-Agent technology. Inthe following, we will show how agents are able to offera distributed, context-aware, reactive and autonomous support.We propose a multi-agent framework which enables theimplementation Multi-Agent Systems (MAS) for emergencyscenarios management
Implementing Agent Interoperability Between Language-Heterogeneous Platforms
No full textOne of the most important feature of a MAS (Multi-AgentSystem) is the cooperation and the coordination amongagents placed in distributed environments. Due to the highheterogeneity of agents and platforms, interoperability hasbecome a key issue for the use of MASs in academic and industrialfields. Several approaches to interoperability proposedso far are based on the JAVA technology exploitingthe homogeneity of the programming language and technology.In this paper we introduce a new middleware thatenables the interoperability among agents execution in differentplatforms. Our approach is FIPA-IEEE compliantand language independent
Multicarrier digital fractional fourier transform for coherent optical communications
No full textA new coherent optical transmission system is proposed that makes use of the digital multicarrier fractional Fourier transform to obtain serial optical Nyquist pulses at the receiver side in the time domain by adopting the time-lens effect. Theoretical time-lens effect is derived based on fractional Fourier transform (FrFT) and chromatic dispersion effect. A fundamental study to explore the limits of the proposed system is performed and detailed results have been presented. System performance evaluation confirms reduced complexity at the receiver side
Keyword-based Search in Data Integration Systems
No full textIn this paper we describe Keymantic, a framework for translating keywordqueries into SQL queries by assuming that the only available information isthe source metadata, i.e., schema and some external auxiliary information. Sucha framework finds application when only intensional knowledge about the datasource is available like in Data Integration Systems
Keyword search over relational databases: a metadata approach
No full textKeyword queries offer a convenient alternative to traditionalSQL in querying relational databases with large, often unknown,schemas and instances. The challenge in answering such queriesis to discover their intended semantics, construct the SQL queriesthat describe them and used them to retrieve the respective tuples.Existing approaches typically rely on indices built a-priori on thedatabase content. This seriously limits their applicability if a-prioriaccess to the database content is not possible. Examples include theon-line databases accessed through web interface, or the sources ininformation integration systems that operate behind wrappers withspecific query capabilities. Furthermore, existing literature has notstudied to its full extend the inter-dependencies across the ways thedifferent keywords are mapped into the database values and schemaelements. In this work, we describe a novel technique for translatingkeyword queries into SQL based on the Munkres (a.k.a. Hungarian)algorithm. Our approach not only tackles the above twolimitations, but it offers significant improvements in the identificationof the semantically meaningful SQL queries that describe theintended keyword query semantics. We provide details of the techniqueimplementation and an extensive experimental evaluation
Multi-Agent approach for Disaster Management
No full textThe emergency situations deriving from naturaldisasters or large scale accidents represent one of the mostcritical activities in the health care system.We are all concernedabout the necessity of a coordinated reaction and organizationwhen there is a large number of people involved and time isa very precious aspect. This paper introduces a multi-agentsystem for the management of the territorial emergencies inlarge scale disasters and shows how the agent technology canmeet successfully the related requirements. In this paper wepropose a multi-agent framework, called Ubimedic2, able tocoordinate autonomously the operative units during the rescueoperation.The emergency situations deriving from natural disasters or large scale accidents represent one of the most critical activities in the health care system. We are all concerned about the necessity of a coordinated reaction and organization when there is a large number of people involved and time is a very precious aspect. This paper introduces a multi-agent system for the management of the territorial emergencies in large scale disasters and shows how the agent technology can meet successfully the related requirements. In this paper, we propose a multi-agent framework, called Ubimedic2, able to coordinate autonomously the operative units during rescue operations
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