225 research outputs found

    Managing software uninstall with negative trust

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    A problematic aspect of software management systems in view of integrity preservation is the handling, approval, tracking and eventual execution of change requests. In the context of the relation between clients and repositories, trust can help identifying all packages required by the intended installation. Negative trust, in turn, can be used to approach the complementary problem induced by removing packages. In this paper we offer a logic for negative trust which allows to identify admissible and no-longer admissible software packages in the current installation profile in view of uninstall processes. We provide a simple working example and the system is formally verified using the Coq theorem prover

    Minimizing transitive trust threats in software management systems

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    We consider security threats in software installation processes, posed by transitively trusted dependencies between packages from distinct repositories. To analyse them, we present SecureNDC, a Coq implemented calculus using an explicit trust function to bridge repository access and software package installation rights. Thereby, we resolve a version of the minimum install problem under trust conditions on repositorie

    Spread and Control of Rift Valley Fever virus after accidental introduction in the Netherlands: a modelling study.

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    Rift Valley Fever (RVF) is a zoonotic vector-borne infection and causes a potentially severe disease in both humans and young animals. The Ministry of Economic Affairs, Agriculture and Innovation (EL&I) is interested in the risk of an outbreak of Rift Valley Fever virus (RVFV) for the Netherlands, and more knowledge is needed about the risk of introduction of the virus, the risk of spread (transmission) of the virus in the country once introduced, and the methods for control and surveillance. For this purpose, a mathematical model was developed to study (1) the probability of a RVF outbreak at different days of introduction during the year, (2) the probability of persistence of the infection during the entire year, and (3) outbreak size and duration at different days of introduction during the year

    Describing and simulating concurrent quantum systems

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    We present a programming language for describing and analysing concurrent quantum systems. We have an interpreter for programs in the language, using a symbolic rather than a numeric calculator, and we give its performance on examples from quantum communication and cryptography

    Teaching functional patterns through robotic applications

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    We present our approach to teaching functional programming to First Year Computer Science stu- dents at Middlesex University through projects in robotics. A holistic approach is taken to the cur- riculum, emphasising the connections between different subject areas. A key part of the students’ learning is through practical projects that draw upon and integrate the taught material. To support these, we developed the Middlesex Robotic plaTfOrm (MIRTO), an open-source platform built using Raspberry Pi, Arduino, HUB-ee wheels and running Racket (a LISP dialect). In this paper we present the motivations for our choices and explain how a number of concepts of functional programming may be employed when programming robotic applications. We present some students’ work with robotics projects: we consider the use of robotics projects to have been a success, both for their value in reinforcing students’ understanding of programming concepts and for their value in motivating the students

    Toxoplasma prevalence in Dutch slaughter pigs in the period 2012-2014

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    Toxoplasma gondii has frequently been named as one of the most important foodborne pathogens, in terms of its impact on human health. EFSA advised to include serological testing of pigs on T. gondii infections and audits of pig farms on risk factors for T. gondii infection (EFSA, 2011). In order to generate knowledge about the epidemiology and prevalence of T. gondii infections in pig herds we studied the long term seroprevalence on farms, persistence of infection and variation in results between and within farms. Sera which were routinely taken in Dutch pig slaughterhouses in the Netherlands for the serological monitoring of Mycobacterium avium infections in pigs (Hiller 2013) were also tested for anti T. gondii antibodies. Results of 120,666 sera, collected from January 2012 until August 2014, showed an average of 2% serological prevalence in pigs. Pigs from organic farms had a prevalence of 3,6%. Farm prevalence was much higher, ranging from approximately 30% for conventional farms to 90% for organic farms. Pigs delivered to the slaughterhouse during winter months had a higher prevalence than pigs delivered during summer months.It could be concluded that serological monitoring can be very useful in detecting farms infected with T. gondii. A test cut off of 20PP was the most appropriate

    Derivation of a Floquet Formalism within a Natural Framework

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    Many biological systems experience a periodic environment. Floquet theory is a mathematical tool to deal with such time periodic systems. It is not often applied in biology, because linkage between the mathematics and the biology is not available. To create this linkage, we derive the Floquet theory for natural systems. We construct a framework, where the rotation of the Earth is causing the periodicity. Within this framework the angular momentum operator is introduced to describe the Earth’s rotation. The Fourier operators and the Fourier states are defined to link the rotation to the biological system. Using these operators, the biological system can be transformed into a rotating frame in which the environment becomes static. In this rotating frame the Floquet solution can be derived. Two examples demonstrate how to apply this natural framework

    Teaching functional patterns through robotic applications

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    We present our approach to teaching functional programming to First Year Computer Science stu- dents at Middlesex University through projects in robotics. A holistic approach is taken to the cur- riculum, emphasising the connections between different subject areas. A key part of the students’ learning is through practical projects that draw upon and integrate the taught material. To support these, we developed the Middlesex Robotic plaTfOrm (MIRTO), an open-source platform built using Raspberry Pi, Arduino, HUB-ee wheels and running Racket (a LISP dialect). In this paper we present the motivations for our choices and explain how a number of concepts of functional programming may be employed when programming robotic applications. We present some students’ work with robotics projects: we consider the use of robotics projects to have been a success, both for their value in reinforcing students’ understanding of programming concepts and for their value in motivating the students
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