Deadlock detection of Java Bytecode

This paper presents a technique for deadlock detection of Java programs. The technique uses typing rules for extracting infinite-state abstract models of the dependencies among the components of the Java intermediate language -- the Java bytecode. Models are subsequently analysed by means of an extension of a solver that we have defined for detecting deadlocks in process calculi. Our technique is complemented by a prototype verifier that also covers most of the Java features.Comment: Pre-proceedings paper presented at the 27th International Symposium on Logic-Based Program Synthesis and Transformation (LOPSTR 2017), Namur, Belgium, 10-12 October 2017 (arXiv:1708.07854

Designing Secure Ethereum Smart Contracts: A Finite State Machine Based Approach

The adoption of blockchain-based distributed computation platforms is growing fast. Some of these platforms, such as Ethereum, provide support for implementing smart contracts, which are envisioned to have novel applications in a broad range of areas, including finance and Internet-of-Things. However, a significant number of smart contracts deployed in practice suffer from security vulnerabilities, which enable malicious users to steal assets from a contract or to cause damage. Vulnerabilities present a serious issue since contracts may handle financial assets of considerable value, and contract bugs are non-fixable by design. To help developers create more secure smart contracts, we introduce FSolidM, a framework rooted in rigorous semantics for designing con- tracts as Finite State Machines (FSM). We present a tool for creating FSM on an easy-to-use graphical interface and for automatically generating Ethereum contracts. Further, we introduce a set of design patterns, which we implement as plugins that developers can easily add to their contracts to enhance security and functionality

Caractérisation physico-chimique des argiles fibreuses de « Souk el Arbaa » du Gharb, Maroc

Le présent travail s’intéresse à l’étude de la qualité industrielle des argiles fibreuses de ‘Souk El Arbaa’ du Gharb appartenant à l’étage géologique Eocène-Miocène. Cette étude a révélé à travers l’analyse d’une vingtaine d’échantillons, prélevés sur des niveaux marneux variés, par spectrométrie à fluorescence X une carence en fer, une richesse en CaO, des taux plus ou moins élevés en Al2O3. La diffractométrie aux rayons X a permis de mettre en évidence une composition minéralogique assez variée dans les différents échantillons analysées, dominée par la présence de paragenèses minéralogiques composées de calcite, dolomite, quartz, sépiolite et attapulgite (argiles fibreuses). Ainsi, le chimisme des échantillons analysés indique d’une façon inéluctable que les argiles de ‘Souk El Arbaa’ du Gharb nécessitent un traitement afin de les rendre exploitables pour la production de céramique d’excellente qualité.Mots-clés : qualité industrielle, argiles fibreuses, Eocène-Miocène, céramique, Maroc

A theory of normed simulations

In existing simulation proof techniques, a single step in a lower-level specification may be simulated by an extended execution fragment in a higher-level one. As a result, it is cumbersome to mechanize these techniques using general purpose theorem provers. Moreover, it is undecidable whether a given relation is a simulation, even if tautology checking is decidable for the underlying specification logic. This paper introduces various types of normed simulations. In a normed simulation, each step in a lower-level specification can be simulated by at most one step in the higher-level one, for any related pair of states. In earlier work we demonstrated that normed simulations are quite useful as a vehicle for the formalization of refinement proofs via theorem provers. Here we show that normed simulations also have pleasant theoretical properties: (1) under some reasonable assumptions, it is decidable whether a given relation is a normed forward simulation, provided tautology checking is decidable for the underlying logic; (2) at the semantic level, normed forward and backward simulations together form a complete proof method for establishing behavior inclusion, provided that the higher-level specification has finite invisible nondeterminism.Comment: 31 pages, 10figure

A Goal-Oriented Autonomous Controller for Space Exploration

The Goal-Oriented Autonomous Controller (GOAC) is the envisaged result of a multi-institutional effort within the on-going Autonomous Controller R&D activity funded by ESA ESTEC. The objective of this effort is to design, build and test a viable on-board controller to demonstrate key concepts in fully autonomous operations for ESA missions. This three-layer architecture is an integrative effort to bring together four mature technologies; for a functional layer, a verification and validation system, a planning engine and a controller framework for planning and execution which uses the sense-plan-act paradigm for goal oriented autonomy. GOAC as a result will generate plans in situ, deterministically dispatch activities for execution, and recover from off-nominal conditions

Analysis of \Lambda_b \rar \Lambda \ell^+ \ell^- transition in SM4 using form factors from Full QCD

Using the responsible form factors calculated via full QCD, we analyze the $\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-}$ transition in the standard model containing fourth generation quarks (SM4). We discuss effects of the presence of $t'$ fourth family quark on related observables like branching ratio, forward-backward asymmetry, baryon polarization as well as double lepton polarization asymmetries. We also compare our results with those obtained in the SM as well as with predictions of the SM4 but using form factors calculated within heavy quark effective theory. The obtained results on branching ratio indicate that the $\Lambda_{b}\rightarrow \Lambda \ell^{+}\ell^{-}$ transition is more probable in full QCD comparing to the heavy quark effective theory. It is also shown that the results on all considered observables in SM4 deviate considerably from the SM predictions when $m_{t'}\geq 400 GeV$.Comment: 22 Pages and 21 Figure

Composing Communicating Systems, Synchronously

Conference moved to 2021 due to covid-19International audienceCommunicating systems are nowadays part of everyday life, yet programming and analysing them is difficult. One of the many reasons for this difficulty is their size, hence compositional approaches are a need. We discuss how to ensure relevant communication properties such as deadlock freedom in a compositional way. The idea is that communicating systems can be composed by taking two of their participants and transforming them into coupled forwarders connecting the two systems. It has been shown that, for asynchronous communications, if the participants are "compatible" then composition satisfies relevant communication properties provided that the single systems satisfy them. We show that such a result changes considerably for synchronous communications. We also discuss a different form of composition, where a unique forwarder is used

Constraint on compactification scale via recently observed baryonic Λb→Λℓ+ℓ−\Lambda_b\rightarrow \Lambda \ell^+ \ell^- channel and analysis of the Σb→Σℓ+ℓ−\Sigma_b \rightarrow \Sigma \ell^+ \ell^- transition in SM and UED scenario

We obtain a lower limit on the compactification scale of extra dimension via comparison of the branching ratio in the baryonic $\Lambda_b\rightarrow \Lambda \mu^+ \mu^-$ decay channel recently measured by CDF collaboration and our previous theoretical study. We also use the newly available form factors calculated via light cone QCD sum rules in full theory to analyze the flavour changing neutral current process of the $\Sigma_b \rightarrow \Sigma \ell^+ \ell^-$ in universal extra dimension scenario in the presence of a single extra compact dimension. We calculate various physical quantities like branching ratio, forward-backward asymmetry, baryon polarizations and double lepton polarization asymmetries defining the decay channel under consideration. We also compare the obtained predictions with those of the standard model.Comment: 32 Pages, 27 Figures and one Tabl