2,694 research outputs found

    Comprehensive Security Framework for Global Threats Analysis

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    Cyber criminality activities are changing and becoming more and more professional. With the growth of financial flows through the Internet and the Information System (IS), new kinds of thread arise involving complex scenarios spread within multiple IS components. The IS information modeling and Behavioral Analysis are becoming new solutions to normalize the IS information and counter these new threads. This paper presents a framework which details the principal and necessary steps for monitoring an IS. We present the architecture of the framework, i.e. an ontology of activities carried out within an IS to model security information and User Behavioral analysis. The results of the performed experiments on real data show that the modeling is effective to reduce the amount of events by 91%. The User Behavioral Analysis on uniform modeled data is also effective, detecting more than 80% of legitimate actions of attack scenarios

    Effect of operating conditions and physico–chemical properties on the wet granulation kinetics in high shear mixer

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    The wet granulation process is sensitive to changes in product properties and process variables. The optimal process and formulation are based on the knowledge of the granule growth mechanisms and of the effects of product properties and process variables. This paper presents the study of wet granulation of microcrystalline cellulose powder, MCC (Avicel PH101) using high-shear mixer granulator. It aims at understanding the effect of operating parameters (impeller rotational speed, liquid binder flow ate) and of physicochemical properties (viscosity, wettability) of a binder solution on solid particles surfaces, on the agglomeration kinetics. The experiments are carried out with water, aqueous solutions of sodium carboxymethylcellulose, polyvinylpyrrolidone, hydroxypropylméthylcellulose or a non ionic surfactant oxo-C10C6 at a critical micellar concentration. Concerning the process variables the experimental results show that an optimal interval of impeller speed operation exists ranging from 150 to 200 rpm for granule growth. Below, an uncontrollable agglomerate size and localised over-wetting occur, and above granule breakage occurs. Increasing the liquid binder flow rate reduces the extension of the non growth regime, but does not affect the granule mean size. The effect of the physicochemical properties is evaluated using a modified capillary viscous number, Ca′, that we define as the ratio between the viscous forces (μLU) and the work of adhesion Wa=γL(1+cosθ). For Ca′b1, the viscosity of the solution does not significantly affect the granulation process. The dominant forces in the granulation process are the interfacial forces since increasing the work of adhesion enhances the growth kinetics. For Ca′N1.6, the viscous forces predominate and control the granule growth

    A Product Oriented Modelling Concept: Holons for systems synchronisation and interoperability

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    Nowadays, enterprises are confronted to growing needs for traceability, product genealogy and product life cycle management. To meet those needs, the enterprise and applications in the enterprise environment have to manage flows of information that relate to flows of material and that are managed in shop floor level. Nevertheless, throughout product lifecycle coordination needs to be established between reality in the physical world (physical view) and the virtual world handled by manufacturing information systems (informational view). This paper presents the "Holon" modelling concept as a means for the synchronisation of both physical view and informational views. Afterwards, we show how the concept of holon can play a major role in ensuring interoperability in the enterprise context

    Density functional study of copper segregation in aluminum

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    The structural and electronic properties of Cu segregation in aluminum are studied in the framework of the density functional theory, within the projector augmented plane-wave method and both its local density approximation (LDA) and generalized gradient approximation (GGA). We first studied Al–Cu interactions in bulk phase at low copper concentration (≤3.12%: at). We conclude to a tendency to the formation of a solid solution at T=0 K. We moreover investigated surface alloy properties for varying compositions of a Cu doped Al layer in the (111) Al surface then buried in an (111) Al slab. Calculated segregation energies show unstable systems when Cu atoms are in the surface position (position 1). In the absence of ordering effects for Cu atoms in a layer (xCu=1/9 and xCu=1/3), the system is more stable when the doped layer is buried one layer under the surface (position 2), whereas for xCu=1/2 to xCu=1 (full monolayer), the doped layer is more accommodated when buried in the sub-sub-surface (position 3). First stage formation of GP1- and GP2-zones was finally modeled by doping (100) Al layers with Cu clusters in a (111) Al slab, in the surface then buried one and two layers under the surface. These multilayer clusters are more stable when buried one layer beneath the surface. Systems modeling GP1-zones are more stable than systems modeling GP2-zones. However the segregation of a full copper (100) monolayer in an (100) Al matrix shows a copper segregation deep in the bulk with a segregation barrier. Our results fit clearly into a picture of energetics and geometrical properties dominated by preferential tendency to Cu clustering close to the (111) Al surface
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