320 research outputs found

    Using Argumentation Logic for Firewall Policy Specification and Analysis

    Get PDF
    Firewalls are important perimeter security mechanisms that imple-ment an organisation's network security requirements and can be notoriously difficult to configure correctly. Given their widespread use, it is crucial that network administrators have tools to translate their security requirements into firewall configuration rules and ensure that these rules are consistent with each other. In this paper we propose an approach to firewall policy specification and analysis that uses a formal framework for argumentation based preference reasoning. By allowing administrators to define network abstractions (e.g. subnets, protocols etc) security requirements can be specified in a declarative manner using high-level terms. Also it is possible to specify preferences to express the importance of one requirement over another. The use of a formal framework means that the security requirements defined can be automatically analysed for inconsistencies and firewall configurations can be automatically generated. We demonstrate that the technique allows any inconsistency property, including those identified in previous research, to be specified and automatically checked and the use of an argumentation reasoning framework provides administrators with information regarding the causes of the inconsistency

    Universal vortex formation in rotating traps with bosons and fermions

    Full text link
    When a system consisting of many interacting particles is set rotating, it may form vortices. This is familiar to us from every-day life: you can observe vortices while stirring your coffee or watching a hurricane. In the world of quantum mechanics, famous examples of vortices are superconducting films and rotating bosonic 4^4He or fermionic 3^3He liquids. Vortices are also observed in rotating Bose-Einstein condensates in atomic traps and are predicted to exist for paired fermionic atoms. Here we show that the rotation of trapped particles with a repulsive interaction leads to a similar vortex formation, regardless of whether the particles are bosons or (unpaired) fermions. The exact, quantum mechanical many-particle wave function provides evidence that in fact, the mechanism of this vortex formation is the same for boson and fermion systems.Comment: 4 pages, 4 figure

    The utilization of sodium lignosulphonate extracted from Egyptian rice straw in leather tanning process

    Get PDF
    Massive quantities of rice straw are burned annually in Egypt and caused environmental hazards. The present study investigated the utilization of rice straw to produce sodium lignosulphonate (SLS) as a water-soluble derivative of lignin in leather tanning and evaluate its usage as a tanning or re-tanning material as well as its effect on leather quality. The results of testing SLS as a leather tanning agent were unsatisfactory due to its slight effect on shrinkage temperature of leathers, unlike its use as a re-tanning material. Four concentrations of SLS (0%, 5%, 10%, and 20%) were used in re-tanning forty of sheep wet-blues. The results showed that using SLS as a re-tanning agent with concentration till 10% from pelts weight enhances some organoleptic properties, such as fullness and general appearance together with slight improvement in physical properties of leathers. Moreover, the addition of SLS with concentration 20% led to an excessive swelling in the collagen fibers as shown from depicted scanning electron micrographs and decreased trends of physical properties

    Investigation of optical and electrical properties of Cobalt-doped Ge-Sb-S thin film

    Get PDF
    Amorphous Germanium Antimony Sulphide (Ge-Sb-S) doped with Cobalt (Co) have been deposited on glass substrates by thermal evaporation technique on a glass substrate. The films deposited onto glass substrates are characterized by Energy Dispersive X-ray Fluorescence Spectrometer, UV–VIS spectrophotometer, Raman spectroscopy, and Capacitance-Voltage Keithley meter. The optical band gap was calculated from the UV–Visible spectrum and found to be 2.05 eV. Raman spectroscopy measurements reveal that a wide band spectrum from 300 to 410 cm−1 centered at 355 cm−1. The Raman shift peaks at 325 cm−1 and 350 cm−1 are as-signed to the bond stretching mode Sb-S and Ge-S, respectively. In addition, from the obtained Raman spectra it is concluded that the presence of Co doped with Ge-Sb-S. The capacitance and conductance versus voltage measurements were performed at different temperatures. The results show a slight increase in the capacitance with temperature and it reaches a maximum value around 150 °C, and eventually it becomes negative. This behavior is interpreted in terms of the nucleation growth process and the thermally activated conduction process with measured activation energy of 0.79 eV.This work is funded by the University Program for Advanced Research - United Arab Emirates University , (project no. 31S313 ).Scopu

    Markov modeling of moving target defense games

    Get PDF
    We introduce a Markov-model-based framework for Moving Target Defense (MTD) analysis. The framework allows modeling of broad range of MTD strategies, provides general theorems about how the probability of a successful adversary defeating an MTD strategy is related to the amount of time/cost spent by the adversary, and shows how a multi-level composition of MTD strategies can be analyzed by a straightforward combination of the analysis for each one of these strategies. Within the proposed framework we define the concept of security capacity which measures the strength or effectiveness of an MTD strategy: the security capacity depends on MTD specific parameters and more general system parameters. We apply our framework to two concrete MTD strategies

    Effect of intracoronary glycoprotein IIb/IIIa inhibitor and manual aspiration thrombectomy on primary percutaneous coronary intervention outcome in high thrombus burden patients

    Get PDF
    Background: The opening of a related artery in myocardial infarction as quickly as possible is the key to treating infarct. Percutaneous coronary intervention (PCI) for recanalization of related infarcted arteries is considered the most effective therapy for myocardial infarction.Objective: To estimate the intracoronary delivery of glycoprotein IIb/IIIa following manual thrombus aspiration on outcomes post PCI for patients with high thrombus burden.Patients and Methods: This was a randomized control trial that was conducted on 48 patients presented to Zagazig University Hospital Emergency Cardiac Unit with ST elevation myocardial infarction for primary percutaneous coronary intervention, the need for reperfusion therapy was assessed according the European Society of Cardiology (ESC) Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation. Patients were randomized into three groups: (1) Manual aspiration group (16 patients). (2) Manual aspiration with intracoronary glycoprotein IIb/IIIa group (19 patients), and (3) Intracoronary glycoprotein IIb/IIIa group (13 patients).Results: There was significant difference between manual aspiration group, manual aspiration with intracoronary glycoprotein IIb/IIIa group and intracoronary glycoprotein IIb/IIIa group as regard the outcomes in high thrombus burden patients.Conclusion: Combination glycoprotein IIb/IIIa and manual aspiration is better then single modality for high thrombus burden patients

    Introduced marine macroflora of Lebanon and its distribution on the Levantine coast

    Get PDF
    The marine macroflora introduced into Lebanon was studied through an analysis of historical data and field studies carried out since 1991. A total of 29 introduced species have been listed: 3 Chromobionta, 13 Rhodobionta, 12 Chlorobionta and 1 Streptobionta. Among them, Caulerpa taxifolia var. distichophylla, Spatoglossum variabile and Womersleyella setacea are recorded for the first time from Lebanon. Among them, Asparagopsis taxiformis, C. taxifolia var. distichophylla, Cladophora patentiramea, Codium arabicum, Codium parvulum, Galaxaura rugosa, Halophila stipulacea, Hypnea cornuta, Laurencia cf. chondrioides, Lophocladia lallemandii, Stypopodium schimperi, Ulva lactuca and Womersleyella setacea are potentially invasive species, and several of them already occupy extensive stretches of the Lebanese coast. The distribution of species on the Levantine coast, their dynamics and the current status of their populations are discussed.The surveys in 2012, 2013 and 2016 were conducted within the framework of the MedMPAnet Project, implemented by UNEP/MAP-RAC/SPA and funded by RAC/SPA, the European Commission (EC), the Spanish Agency for International Cooperation for Development (AECID), and the French Global Environment Facility (FFEM)
    corecore