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Risk analysis is an important tool for developers to establish the appropriate protection level of a system. Unfortunately, the shifting environment of components and component-based systems is not adequately addressed by traditio...
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Risk analysis is an important tool for developers to establish the appropriate protection level of a system. Unfortunately, the shifting environment of components and component-based systems is not adequately addressed by traditional risk analysis methods. This paper addresses this problem from a theoretical perspective by proposing a denotational model for component-based risk analysis. In order to model the probabilistic aspect of risk, we represent the behaviour of a component by a probability distribution over communication histories. The overall goal is to provide a theoretical foundation facilitating an improved understanding of risk in relation to components and component-based system development.
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UML Interactions represent one of the three different behavior kinds of the UML. In general, they specify the exchange of messages among parts of a system. Although UML Interactions can reside on different level of abstractions, t...
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UML Interactions represent one of the three different behavior kinds of the UML. In general, they specify the exchange of messages among parts of a system. Although UML Interactions can reside on different level of abstractions, they seem to be sufficiently elaborated for a higher-level of abstraction where they are used for sketching the communication among parts. Its metamodel reveals some fuzziness and imprecision where definitions should be accurate and concise, though. In this paper, we propose improvements to the UML Interactions' metamodel for Message arguments and Loop CombinedFragments that make them more versatile. We will justify the needs for the improvements by precisely showing the shortcomings of the related parts of the metamodel. We demonstrate the expressiveness of the improvements by applying them to examples that current Interactions definition handles awkwardly.
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After the launch to the ISS (International Space Station) with The Space Shuttle flight STS 118 13A.1 on August 9th 2007 and the accommodation in the US lab Destiny, the air quality monitor ANITA (Analyzing Interferometer for Ambi...
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After the launch to the ISS (International Space Station) with The Space Shuttle flight STS 118 13A.1 on August 9th 2007 and the accommodation in the US lab Destiny, the air quality monitor ANITA (Analyzing Interferometer for Ambient Air) was successfully put into operation. ANITA is a technology demonstrator flight experiment able to continuously monitor with high time resolution the air conditions within the crewed cabins of the ISS. The system has its origin in a long-term ESA technology development program. The ANITA mission itself is an ESA-NASA cooperative project. ESA is responsible for the provision of the HW, the data acquisition and data evaluation. NASA's responsibilities are launch, accommodation in the US Lab Destiny, operation and data download.
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In this paper, we propose a one-dimensional multi-mixture model to simulate sand transport in stratified gas-liquid two-phase pipeline flow. The approach assumes that the flow consists of a sand bed and two mixture layers: liquid-...
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In this paper, we propose a one-dimensional multi-mixture model to simulate sand transport in stratified gas-liquid two-phase pipeline flow. The approach assumes that the flow consists of a sand bed and two mixture layers: liquid-continuous with dispersed particles and gas-continuous with dispersed droplets. The proposed model comprises one momentum equation for each mixture layer and four mass conservation equations: continuous liquid, continuous gas, droplets and sand particles, The multi-mixture model was validated against experimental in-house data,, A parametric study was presented; the parameters considered are liquid flow rate, gas flow rate, and pipe inclination.
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The paper makes two main contributions: (1) It presents experiences from using the CORAS language for security threat modelling to specify legal risk scenarios. These experiences are summarised in the form of requirements to a mor...
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The paper makes two main contributions: (1) It presents experiences from using the CORAS language for security threat modelling to specify legal risk scenarios. These experiences are summarised in the form of requirements to a more expressive language providing specific support for the legal domain. (2) Its second main contribution is to present ideas towards the fulfilment of these requirements. More specifically, it extends the CORAS conceptual model for security risk analysis with legal concepts and associations. Moreover, based on this extended conceptual model, it introduces a number of promising language constructs addressing some of the identified deficiencies.
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摘要 :
The paper makes two main contributions: (1) It presents experiences from using the CORAS language for security threat modelling to specify legal risk scenarios. These experiences are summarised in the form of requirements to a mor...
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The paper makes two main contributions: (1) It presents experiences from using the CORAS language for security threat modelling to specify legal risk scenarios. These experiences are summarised in the form of requirements to a more expressive language providing specific support for the legal domain. (2) Its second main contribution is to present ideas towards the fulfilment of these requirements. More specifically, it extends the CORAS conceptual model for security risk analysis with legal concepts and associations. Moreover, based on this extended conceptual model, it introduces a number of promising language constructs addressing some of the identified deficiencies.
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LedaFlow is a transient multiphase flow simulator under development with both ID and multidimensional capabilities. The LedaFlow ID model is a mechanistic, multi-fluid model consisting of mass, momentum, and energy conservation eq...
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LedaFlow is a transient multiphase flow simulator under development with both ID and multidimensional capabilities. The LedaFlow ID model is a mechanistic, multi-fluid model consisting of mass, momentum, and energy conservation equations for each field (continuous, bubble and droplet), as well as compositional tracking. LedaFlow ID is one of the core elements of the suite of computational tools, providing boundary conditions for the more complex, multi-dimensional simulations, as well as serving as a stand-alone feature, similar to other transient ID codes.
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C72900 is a copper alloy containing 15% Ni and 7% Sn that combines high strength with anti-galling properties, it is non-magnetic, is easy to machine and has acceptable corrosion resistance in selected environments. The alloy has ...
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C72900 is a copper alloy containing 15% Ni and 7% Sn that combines high strength with anti-galling properties, it is non-magnetic, is easy to machine and has acceptable corrosion resistance in selected environments. The alloy has been used in bushings and bearings for aircraft, industrial equipment and heavy equipment. It is also used for oil and gas environments. In the open literature limited information about corrosion properties and resistance against hydrogen embrittlement (HE) have been published. However, material suppliers have published test results concluding that i) corrosion rate in seawater < 20 μm/year, ii) the material is not exposed to HE under cathodic protection in seawater, iii) the material is approved according to NACE MR0175 for use at NACE Levels I, IV and V with uniform corrosion rate below 100 μm/year. This paper presents results from testing of resistance against HE for Toughmet 3 AT110 alloy. The material has been tested against; i) sulfide stress cracking (SSC) according to ISO 15156-3 Level V by use of the four point bend (4PB) method, and ii) cathodic polarization in simulated seawater with specimens under tensile load. The outcome from the test program can be summarized as; 1. The results from SSC testing according to ISO 15156 Level V contradict the information given in the suppler information. 1.1 Severe transgranular cracks observed 1.2 Severe uniform - in the order of 1.2 mm/year - and pitting corrosion observed 2. The alloy did not suffer from hydrogen stress cracking (HSC) during tensile load above yield stress and cathodic polarization in seawater.
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As part of the development of the LedaFlow multiphase simulation tool, experiments
have been performed to investigate detailed flux- and velocity profiles in two-phase
flows with Nitrogen and Naphtha. The experiments have been r...
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As part of the development of the LedaFlow multiphase simulation tool, experiments
have been performed to investigate detailed flux- and velocity profiles in two-phase
flows with Nitrogen and Naphtha. The experiments have been recorded in an 8 inch
diameter pipe with 0.5° inclination at 20 and 90 bar pressure. Results and implications
from these measurements are discussed. Next, a detailed model for droplet entrainment is
presented. The experimental data is analysed based on the proposed model framework
and the model is calibrated using the available measurements. The subsequent results are
discussed.
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摘要 :
As part of the development of the LedaFlow multiphase simulation tool, experiments have been performed to investigate detailed flux- and velocity profiles in two-phase flows with Nitrogen and Naphtha. The experiments have been rec...
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As part of the development of the LedaFlow multiphase simulation tool, experiments have been performed to investigate detailed flux- and velocity profiles in two-phase flows with Nitrogen and Naphtha. The experiments have been recorded in an 8 inch diameter pipe with 0.5° inclination at 20 and 90 bar pressure. Results and implications from these measurements are discussed. Next, a detailed model for droplet entrainment is presented. The experimental data is analysed based on the proposed model framework and the model is calibrated using the available measurements. The subsequent results are discussed.
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