1,721,092 research outputs found
PRISM+
No full textPRISMisaprobabilisticmodelchecker,atoolforformalmodellingandanal- ysis of systems that exhibit random or probabilistic behaviour. We extend the language in order to model the Bitcoin system. The tool now supports three dynamic data types: block, ledger and list. As consequence, it is now possible to perform simulations and analyse transient probabilities, i.e. probabilities that are dependent on time, for the Bitcoin protocol. It has been used to under- stand how the system changes during the execution and to analyse the probabilities of reaching an inconsistent state in different settings
JaDA - A Static Java Deadlock Analizer
No full textJaDA detects deadlocks of Java programs at static time. The tool uses typing rules to extract infinite-state abstract models of the dependencies among the diferent components of the Java intermediate language JVML, the Java bytecode. These models are subsequently analyzed by means of a fixpoint decision algorithm that we have defined for detecting deadlocks in process calculi. JaDA also exhibits the executions causing deadlocks and allows users to analyze false positives. This prototype covers most of the Java language features
Liquidity Analysis in Resource-Aware Programming
Full text linkLiquidity is a liveness property of programs managing resources that pinpoints those programs not freezing any resource forever. We consider a simple stateful language whose resources are assets (digital currencies, non fungible tokens, etc.). Then we define a type system that tracks in a symbolic way the input- output behaviour of functions with respect to assets. These types and their composition, which define types of computations, allow us to design two algorithms for liquidity that have different precisions and costs. We also demonstrate the correctness of the algorithms
The Stipula Prototype
No full textStipula is a domain specific language that may assist legal practitioners in programming legal contracts through specific patterns. In this repository, we uploaded the prototype and some examples.
The prototype is a Java application. The development has taken three months and ~3000 lines of Java code. We have committed to the ANTLR tool
An Algebraic Theory for Web Service Contracts
Full text linkWe study a natural notion of compliance between clients and services in terms of their BPEL (abstract) descriptions. The induced preorder shows interesting connections with the must preorder and has normal form representatives that are parallel-free finite-state activities, called contracts. The preorder also admits the notion of least service contract that is compliant with a client contract, called principal dual contract. Our framework serves as a foundation of Web service technologies for connecting abstract and concrete service definitions and for service discovery
Il cinema sulla scuola per l'innovazione delle pratiche didattiche
No full textNel saggio si chiarisce come il film possa entrare a pieno titolo nei percorsi universitari di formazione degli insegnanti o per la formazione di docenti già in servizio. Lo stesso supporto filmico può svolgere anche un ruolo di facilitazione nei processi di ricerca sulle pratiche insegnative. Nello scritto si prende in considerazione e si analizza una serie di opere cinematografiche ritenute significative e si indica per quali motivi esse si possano ritenere pertinenti sia al lavoro di formazione sia in sede di ricerca
Lo sguardo della memoria. Rileggendo "Il Piccolo Principe"
No full textIl volume ripercorre, attraverso un'ottica interdisciplinare e un'ermenentica raffinata e complessa, i significati più nascosti de Il Piccolo Principe
A Formal Analysis of the Bitcoin Protocol
Full text linkWe study Nakamoto’s Bitcoin protocol that implements a distributed ledger on peer-to-peer asynchronous networks. In particular, we define a principled formal model of key participants - the miners - as stochastic processes and describe the whole system as a parallel composition of miners. We therefore compute the probability that ledgers turn into a state with more severe inconsistencies, e.g. with longer forks, under the assumptions that messages are not lost and nodes are not hostile. We also study how the presence of hostile nodes mining blocks in wrong positions impacts on the consistency of the ledgers. Our theoretical results agree with the simulations performed on a probabilistic model checker that we extended with dynamic datatypes in order to have a faithful description of miners' behaviour
Scrivere e apprendere nella condizione postmediale
No full textThe author addresses the issue of writing practices within the contemporary media landscape, which he defines a “post-media condition”; indeed, media presence is presently pervasive but unnoticed, since media are an integrated component of everyday experience.
In this context, two elements define writing practices. On the one hand, they are widespread, “naturalized”, and intermodal – i.e. we can’t perceive substantial differences between the different modes of writing, from the verbal to the visual or audiovisual one. On the other hand, writing practices and productions play a fundamental role in the construction and representation of social bond within the information networks.
In its conclusions, the author questions opportunities for the institutional teaching of writing practices. He argues that high complexity writing practices represent the specific scope of teaching institution; indeed, this kind of practices require special skills linked to design competence and critical approach, which cannot be transmitted within non-institutional contexts
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