740 research outputs found

    Introducing Authenticated Information in a Reliable Multicast Protocol for Mobile Computing

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    We consider a known protocol for reliable multicast in distributed mobile systems where mobile hosts belonging to a group communicate with a wired infrastructure by means of wireless technology. The original specification of the protocol does not take into consideration any notion of computer security. In this paper it is shown how an adversary may eavesdrop on communications between legitimate members and inject packets over the wireless links, pretending to be a legitimate member belonging to the group. We suggest a revised version of the protocol providing authenticity and integrity of packets over the wireless links

    Using abstract interpretation to add type checking for interfaces in Java bytecode verification

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    AbstractJava interface types support multiple inheritance. Because of this, the standard bytecode verifier ignores them, since it is not able to model the class hierarchy as a lattice. Thus, type checks on interfaces are performed at run time. We propose a verification methodology that removes the need for run-time checks. The methodology consists of: (1) an augmented verifier that is very similar to the standard one, but is also able to check for interface types in most cases; (2) for all other cases, a set of additional simpler verifiers, each one specialized for a single interface type. We obtain these verifiers in a systematic way by using abstract interpretation techniques. Finally, we describe an implementation of the methodology and evaluate it on a large set of benchmarks

    Heuristic search for equivalence checking

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    Equivalence checking plays a crucial role in formal verification since it is a natural relation for expressing the matching of a system implementation against its specification. In this paper, we present an efficient procedure, based on heuristic search, for checking well-known bisimulation equivalences for concurrent systems specified through process algebras. The method tries to improve, with respect to other solutions, both the memory occupation and the time required for proving the equivalence of systems. A prototype has been developed to evaluate the approach on several examples of concurrent system specifications

    Photocatalytic inactivation of Escherichia coli bacteria in water using low pressure plasma deposited TiO2 cellulose fabric

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    Fabrics obtained from cellulose spinning, extracted from Spanish broom, were coated with TiO2 film, through the low pressure plasma sputtering technique, in order to get antibacterial activity. The obtained fabrics were used for the photocatalytic degradation of Escherichia coli, by irradiation with UV-light emitting diodes (UV-LED), in a batch photocatalytic reactor. Before and after functionalization treatments, cellulosic substrates were chemically characterized by X-ray photoelectron spectroscopy (XPS) analyses. Water Contact Angle (WCA) measurements allowed obtaining information about the hydrophilicity of the materials, while their antibacterial efficiency was determined at several initial concentrations (from 103 up to 108 CFU mL−1) of bacteria in distilled water, bottled water and synthetic wastewater. It was found that photocatalytic reactions were capable of achieving up to 100% bacterial inactivation in 1 h of treatment, following a pseudo-first order kinetic model. No bacterial regrowth was observed after photocatalytic treatments in almost all experimental conditions. In contrast, during photolytic treatment (i.e. in the absence of the TiO2 coated fabrics) bacteria recovered their initial concentration after 3 h in the dark. Finally, the reusability of the plasma modified fibers to inactivate bacteria was studied

    Properties of patchy colloidal particles close to a surface: a Monte Carlo and density functional study

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    We investigate the behavior of a patchy particle model close to a hard-wall via Monte Carlo simulation and density functional theory (DFT). Two DFT approaches, based on the homogeneous and inhomogeneous versions of Wertheim's first order perturbation theory for the association free energy are used. We evaluate, by simulation and theory, the equilibrium bulk phase diagram of the fluid and analyze the surface properties for two isochores, one of which is close to the liquid side of the gas-liquid coexistence curve. We find that the density profile near the wall crosses over from a typical high-temperature adsorption profile to a low-temperature desorption one, for the isochore close to coexistence. We relate this behavior to the properties of the bulk network liquid and find that the theoretical descriptions are reasonably accurate in this regime. At very low temperatures, however, an almost fully bonded network is formed, and the simulations reveal a second adsorption regime which is not captured by DFT. We trace this failure to the neglect of orientational correlations of the particles, which are found to exhibit surface induced orientational order in this regime

    Spatial evolution of the December 2013 Metaponto plain (Basilicata, Italy) flood event using multi-source and high-resolution remotely sensed data

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    We present a multi-layer, multi-temporal flood map of the event occurred on December 2013 in Basilicata (southern Italy), documenting the spatial evolution of the inundated areas through time, as well as some ground effects of floodwaters inferred from the imagery. The map, developed within a GIS and consisting of four, 1:20,000 scale, different layers, was prepared using image processing, visual image interpretation and field survey controls. We used two COSMO-SkyMed synthetic aperture radar (SAR) images, acquired during the event, and a PlĂšiades-1B High-Resolution optical image, acquired at the end of the event. We also used the information derived from the satellite imagery to update some local features of the OpenStreetMap (OSM) geospatial database, and then integrated it within the flood map. A classified multi-temporal dynamic map of inundation and flood effects has been produced in the form of a multi-layer pdf file (Main Map)

    Performances of low level hospital health caregivers after a neonatal resuscitation course

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    Background: High fidelity simulation has been executed to allow the evaluation of technical and non-technical skills of health caregivers. Our objective was to assess technical and non-technical performances of low level hospitals health caregivers who attended a Neonatal Resuscitation course using high fidelity simulation in a standard-setting scenario. Methods: Twenty-three volunteers were asked to manage a simple scenario (infant with secondary apnea) after the course. Technical and non-technical skills were assessed by using previously published scores. Performances were assessed during the scenario and after 2 months by filmed video recordings. Results: Sixteen (69.5%) participants failed to pass the minimum required technical score. Staff experience and participation in previous courses were associated to higher score in technical and non-technical skills, while working in level I or II hospitals did not affect the scores. Previous experience in neonatal resuscitation requiring positive pressure ventilation was associated to better non-technical performance. Technical and non-technical scores were significantly correlated (r = 0.67, p = 0.0005). Delayed and direct evaluation of technical skills provided the same scores. Conclusions: A neonatal resuscitation course, performed by using a high fidelity simulation manikin, had a limited impact on technical and non-technical skills of participants working in low level hospitals. Training programs should be tailored to the participants\u2019 professional background and to the more relevant sessions

    Carbon Nanotubes Hybrid Hydrogels for Environmental Remediation: Evaluation of Adsorption Efficiency under Electric Field

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    The performance of Carbon Nanotubes hybrid hydrogels for environmental remediation was investigated using Methylene Blue (MB), Rhodamine B (RD), and Bengal Rose (BR) as model contaminating dyes. An acrylate hydrogel network with incorporated CNT was synthesized by photo-polymerization without any preliminary derivatization of CNT surface. Thermodynamics, isothermal and kinetic studies showed favorable sorption processes with the application of an external 12 V electric field found to be able to influence the amount of adsorbed dyes: stronger interactions with cationic MB molecules (qexp and q12exp of 19.72 and 33.45 mg g−1, respectively) and reduced affinity for anionic RD (qexp and q12exp of 28.93 and 13.06 mg g−1, respectively) and neutral BR (qexp and q12exp of 36.75 and 15.85 mg g−1, respectively) molecules were recorded. The influence of pH variation on dyes adsorption was finally highlighted by reusability studies, with the negligible variation of adsorption capacity after five repeated sorption cycles claiming for the suitability of the proposed systems as effective sorbent for wastewater treatment

    NEUROCOGNITIVE MANAGEMENT OF THE PRIMARY NEGATIVE SYMPTOMS OF SCHIZOPHRENIA: A ROLE OF ATYPICAL ANTIPSYCHOTICS

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    Patients with schizophrenia have profound and disabling cognitive deficits while negative symptoms represent a separate symptom domain, with respect to depression, neurocognition, and social cognition. Particularly, primary negative symptoms of schizophrenia represent a diagnostic and therapeutic challenge, In this study we try to evaluate the cognitive symptoms in 51 primary negative schizophrenic inpatients by the administration of simple, fast and understandable scales (MMSE, DSST, EpiTrack, PANSS cognitive factor). We also evaluate the correlation with some SGAs (aripiprazole, quetiapine, olanzapine, paliperidone). Our results support the evidence of the use of simple, rapid and acceptable scales for cognitive evaluation in clinical practice. Overall data indicate no statistically significant variations of the negative symptomatology in all the examined sample, although a reduction of the statistical averages in each group is observed (paliperidone and olanzapine, particularly)

    Y-chromosome polymorphisms and ethnic group – a combined STR and SNP approach in a population sample from northern Italy

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    Aim To find an association between Y chromosome polymorphisms and some ethnic groups. Methods Short tandem repeats (STR) and single-nucleotide polymorphisms (SNP) on the Y chromosome were typed in 311 unrelated men from four different ethnic groups – Italians from northern Italy, Albanians, Africans from the Maghreb region, and Indo-Pakistanis, using the AmpFlSTR¼ Yfiler PCR Amplification Kit and the SNaPshot Multiplex Kit. Results STRs analysis found 299 different haplotypes and SNPs analysis 11 different haplogroups. Haplotypes and haplogroups were analyzed and compared between different ethnic groups. Significant differences were found among all the population groups, except between Italians and Indo-Pakistanis and between Albanians and Indo-Pakistanis. Conclusions Typing both STRs and SNPs on the Y chromosome could become useful in determining ethnic origin of a potential suspec
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