Probing the pc- and kpc-scale environment of the powerful radio galaxy Hercules A

We present the kpc-scale behaviour of the powerful extragalactic radio source Hercules A and the behaviour of the intracluster gas in which the radio source is situated. We have found that Hercules A exhibits a strong Laing-Garrington effect. The X-ray observations have revealed an extended X-ray emission elongated along the radio galaxy axis. The estimated temperature of the cluster is kT = 2.45 keV and the central electron density is no~7.8 x 10^(-3) cm^(-3) which reveals a hot, dense environment in which Hercules A is situated. From the combined study of the radio and X-ray data we have estimated a central value of 3<Bo (muG)<9. We also present the most recent results from the analysis of the radio data on the pc-scale structure of the radio galaxy, observed at 18 cm by the EVN-MERLIN array. A faint but compact radio source, coincident with the optical centre of Hercules A was detected by the EVN at 18 mas resolution. The total flux density of the EVN core is 14.6 mJy. Its angular size is 18 x 7 mas with a position angle of ~139 degrees. There is also evidence for extended emission in the NW-SE direction, most probably from the eastern pc-scale jet. If this is true then there is a misalignment between the direction of the pc-eastern and the aligned kpc-scale jets of ~35 degrees.Comment: 7 pages, 2 figures, Submitted to PAS

AmbieSense: a system and reference architecture for personalised and context-sensitive information services for mobile users

The purpose of AmbieSense is to provide personalised, context-sensitive information to the mobile user. It is about augmenting digital information to physical objects, rooms, and areas. The aim is to provide relevant information to the right user and situation. Digital content is distributed from the surroundings and onto your mobile phone. An ambient information environment is provided by a combination of context tag technology, a software platform to manage and deliver the information, and personal computing devices to which the information is served. This paper describes how the AmbieSense reference architecture has been defined and used in order to deliver information to the mobile citizen at the right time, place and situation. Information is provided via specialist content providers. The application area addresses the information needs of travellers and tourists

Shared task proposal: Instruction giving in virtual worlds

This paper reports on the results of the working group “Virtual Environ-ments ” at the Workshop on Shared Tasks and Comparative Evaluation for NLG. This working group discussed the use of virtual environments as a platform for NLG evaluation, and more specifically of the generation of in

Tools of the Trade: A Survey of Various Agent Based Modeling Platforms

Agent Based Modeling (ABM) toolkits are as diverse as the community of people who use them. With so many toolkits available, the choice of which one is best suited for a project is left to word of mouth, past experiences in using particular toolkits and toolkit publicity. This is especially troublesome for projects that require specialization. Rather than using toolkits that are the most publicized but are designed for general projects, using this paper, one will be able to choose a toolkit that already exists and that may be built especially for one's particular domain and specialized needs. In this paper, we examine the entire continuum of agent based toolkits. We characterize each based on 5 important characteristics users consider when choosing a toolkit, and then we categorize the characteristics into user-friendly taxonomies that aid in rapid indexing and easy reference.Agent Based Modeling, Individual Based Model, Multi Agent Systems

Game engines and MAS: tuplespace-based interaction in Unity3D

I Game Engines stanno acquisendo sempre più importanza sia in ambito industriale, dove permettono lo sviluppo di applicazioni moderne e videogiochi, sia in ambito di ricerca, in particolare nel contesto dei sistemi multi-agente (MAS). La loro capacità espressiva, unita al supporto di tecnologie e funzionalità innovative, permette la creazione di sistemi moderni e complessi in maniera più efficiente: il loro continuo avanzamento tecnologico li ha portati ad essere una realtà su cui fare affidamento nella produzione di vari applicativi diversi, come applicazioni di realtà aumentata/virtuale/mista, simulazioni immersive, costruzione di mondi virtuali e 3D, ecc. Ciononostante, soffrono la mancanza di proprie astrazioni e meccanismi che possano essere affidabili e utilizzati per aggredire la complessità durante il design di sistemi complessi. Il tentativo di sfruttare le caratteristiche della teoria dei MAS all'interno degli ambienti di sviluppo dei Game Engines procede secondo questa direzione: integrando le astrazioni costituenti i MAS all'interno dei Game Engines, con particolare riferimento ai modelli di coordinazione tra agenti, può portare a nuove soluzioni, riuscendo a risolvere problemi tecnologici grazie all'aiuto degli engine grafici. Questa tesi utilizza il Game Engine Unity3D proponendo due librerie C#, le quali sfruttano una precedente integrazione dello stesso framework con il Prolog per l'abilitazione di un modello di interazione e coordinazione basato su spazi di tuple, utilizzabile tramite l'implementazione di primitive LINDA. Le librerie offrono interfacce di programmazione (API) sfruttabili dai programmatori C# Unity3D per integrare nelle loro creazioni il supporto a tale modello, con una nuova modalità per la gestione della coordinazione tra oggetti in Unity3D e fornisce importanti proprietà, essendo fondamentale nel contesto dei MAS dal punto di vista dell'ingegnerizzazione di sistemi complessi e della gestione delle interazioni tra agenti

Agents for educational games and simulations

This book consists mainly of revised papers that were presented at the Agents for Educational Games and Simulation (AEGS) workshop held on May 2, 2011, as part of the Autonomous Agents and MultiAgent Systems (AAMAS) conference in Taipei, Taiwan. The 12 full papers presented were carefully reviewed and selected from various submissions. The papers are organized topical sections on middleware applications, dialogues and learning, adaption and convergence, and agent applications

From Manifesta to Krypta: The Relevance of Categories for Trusting Others

In this paper we consider the special abilities needed by agents for assessing trust based on inference and reasoning. We analyze the case in which it is possible to infer trust towards unknown counterparts by reasoning on abstract classes or categories of agents shaped in a concrete application domain. We present a scenario of interacting agents providing a computational model implementing different strategies to assess trust. Assuming a medical domain, categories, including both competencies and dispositions of possible trustees, are exploited to infer trust towards possibly unknown counterparts. The proposed approach for the cognitive assessment of trust relies on agents' abilities to analyze heterogeneous information sources along different dimensions. Trust is inferred based on specific observable properties (Manifesta), namely explicitly readable signals indicating internal features (Krypta) regulating agents' behavior and effectiveness on specific tasks. Simulative experiments evaluate the performance of trusting agents adopting different strategies to delegate tasks to possibly unknown trustees, while experimental results show the relevance of this kind of cognitive ability in the case of open Multi Agent Systems