1,721,026 research outputs found
An XML view of the world
No full textThe paper presents ”Any Input XML Output” (AIXO), a general and flexible software architecture for wrap- pers. The architecture has been designed to present data sources as collections of XML documents. The use of XSLT as extraction language permits extensive reuse of standards, tools and knowledge. A prototype devel- oped in Java has been effectively proven in several case studies. The tool has also been successfully integrated as a wrapper service into BioAgent, a mobile agent middleware specialized for use in the molecular biology domain
Enacting Proactive Workflows Engine in e-Science
No full textThe dynamic nature and the geographic distribution of scientific resources, require flexible and adaptive computational envi- ronment where an in-silico experiment can be executed as a workflow of activities. In this paper, we propose a software environment to dy- namically generate domain-specific, agent-based workflow engines from workflow specifications. The workflow engine is a proactive multiagent system -a distributed, concurrent system- whose autonomous compo- nents interact in performing the workflow activities in a specific domain. The proposed approach has been implemented on Hermes, agent-based mobile computing middleware, and tested within “Oncology over Inter- net” project
Building a MultiAgent System from a User Workflow Specification
Full text linkThis paper provides a methodology to build
a MultiAgent System (MAS) described in terms of interactive
components from a domain-specic User Workow
Specication (UWS). We use a Petri nets-based notation
to describe workow specications. This, besides using a
familiar and well-studied notation, guarantees an highlevel
of description and independence with more concrete
vendor-specic process denition languages. In order to
bridge the gap between workow specications and MASs,
we exploit other intermediate Petri nets-based notations.
Transformation rules are given to translate a notation to
another. The generated agent-based application implements
the original workow specication. Run-time support is
provided by a middleware suitable for the execution of the
generated code
Composizione musicale e pensiero matematico: un percorso dal primo Novecento alla serialità integrale
No full textIl saggio descrive i rapporti tra composizione musicale e pensiero matematico, tracciando un percorso che va dai primi anni del Novecento fino all’affermazione del serialismo integrale. Viene esposta una tesi secondo la quale gli sviluppi del pensiero matematico si ripercuotono sul pensiero compositivo a un cinquantennio circa di distanza.
L’autore individua tre snodi storici principali. Il primo è all’inizio del secolo, quando la suddivisione dell’ottava in dodici intervalli di uguale ampiezza assume un nuovo significato teorico-musicale. Gli intervalli temperati, e non più gli intervalli naturali, vengono posti, di fatto, alla base della teoria dell’armonia, dando luogo a una visione simmetrica e ciclica dei rapporti tra i suoni. Il secondo momento segna un ulteriore svincolamento dei compositori dalle ‘leggi naturali’ della fisica acustica, a favore di un’idea di ‘autonomia’ del pensiero musicale. Le loro idee sembrano risentire di concetti, come quelli di invarianza o di gruppo, che in ambito scientifico si erano affermati nel secolo precedente, col passaggio da una visione della matematica legata alla descrizione della realtà, a una che concepisce la matematica come un sistema di rappresentazione dotato di una propria indipendenza, fondata sulla sua coerenza interna.
Il terzo e decisivo momento è infine intravisto nella riflessione teorica sulla serialità integrale, alla metà del Novecento. L’enfasi dei compositori sulla necessità di coerenza e logicità dei sistemi teorici soggiacenti alla composizione musicale sembra corrispondere all’idea della necessità di una riformulazione generale della matematica nell’ottica del metodo assiomatico – nel senso del formalismo hilbertiano. Idea che si era affermata ai primi del secolo, come reazione alle contraddizioni aperte dalle geometrie non euclidee.
Il saggio, corredato di numerosi esempi, prende in considerazione sia gli scritti sia le tecniche compositive di numerosi autori e teorici musicali del Novecento
A Logic for Monitoring Dynamic Networks of Spatially-distributed Cyber-Physical Systems
Full text linkCyber-Physical Systems (CPS) consist of inter-wined computational (cyber) and physical components interacting through sensors and/or actuators. Computational elements are networked at every scale and can communicate with each other and with humans. Nodes can join and leave the network at any time or they can move to different spatial locations. In this scenario, monitoring spatial and temporal properties plays a key role in the understanding of how complex behaviors can emerge from local and dynamic interactions. We revisit here the Spatio-Temporal Reach and Escape Logic (STREL), a logic-based formal language designed to express and monitor spatio-temporal requirements over the execution of mobile and spatially distributed CPS. STREL considers the physical space in which CPS entities (nodes of the graph) are arranged as a weighted graph representing their dynamic topological configuration. Both nodes and edges include attributes modeling physical and logical quantities that can evolve over time. STREL combines the Signal Temporal Logic with two spatial modalities reach and escape that operate over the weighted graph. From these basic operators, we can derive other important spatial modalities such as everywhere, somewhere and surround. We propose both qualitative and quantitative semantics based on constraint semiring algebraic structure. We provide an offline monitoring algorithm for STREL and we show the feasibility of our approach with the application to two case studies: monitoring spatio-temporal requirements over a simulated mobile ad-hoc sensor network and a simulated epidemic spreading model for COVID19
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