Modeling Security Policy and the Effect for End-Users

Many "good practices" in computer security are based on assumptions and local evidence that do not generalize. There are few quantifiable methods of establishing or refuting the validity of these practices from a user perspective. We propose a formal model of security policies that allows us to evaluate the claimed benefits to the user of the system quantitatively. We illustrate the use of the model by looking at a security policy we all live with daily: The Password Policy

Current capabilities, requirements and a proposed strategy for interdependency analysis in the UK

The UK government recently commissioned a research study to identify the state-of-the-art in Critical Infrastructure modelling and analysis, and the government/industry requirements for such tools and services. This study (Cetifs) concluded with a strategy aiming to bridge the gaps between the capabilities and requirements, which would establish interdependency analysis as a commercially viable service in the near future. This paper presents the findings of this study that was carried out by CSR, City University London, Adelard LLP, a safety/security consultancy and Cranfield University, defense academy of the UK

The assessment of time lapse marine controlled-source electromagnetics (CSEM) for dynamic reservoir characterisation

Marine controlled-source electromagnetics (CSEM) techniques can be used to detect subsurface resistivity anomalies to discriminate hydrocarbon filled reservoir from the water saturated sediments in pre-drill appraisal of seismic anomalies in hydrocarbon exploration. The governing physics of marine CSEM is electromagnetic induction/diffusion therefore it has poor structural resolution. Current time – lapse CSEM feasibility studies for reservoir monitoring assume that the intrinsic limitation of CSEM has little impact on the dynamic fluid discrimination, as more structural constraining information are available at a producing oilfield. However, basic resistivity model is used without rigorous rock physics model, and is thus lacking in dynamic reservoir characterisation. Recent efforts at utilising simulation models combined with rock physics for realistic water-flooding front did not include reservoir management issues. In this thesis, CSEM is presented from the perspective of a reservoir manager, the end – user of this technology. A review of various hydrocarbon production mechanisms and scenarios showed that water – related mechanisms are ideally suited for time lapse CSEM applications as a complimentary tool to seismic in reservoir monitoring because of the resistivity anomaly generated as water replaces hydrocarbon. Channelized turbidite system for the North Sea oilfield model is used, such that the laminar lithological arrangement of sand and shale indicates that a linear arithmetic summation of resistivities of shale and sand will be a good representative of electrical rock physics model. Using this electrical rock physics model, three hydrocarbon provinces are assessed for the technical risk of time lapse CSEM project, in similar manner as done in 4D seismic projects. The North Sea province has highest technical risk, followed by the Gulf of Mexico, while the West Africa province has the least technical risk. A simulation to electromagnetic (sim2EM) workflow is then incorporated into the simulation to seismic (sim2seis) workflow. The sim2EM workflow is used to first examine the impacts of overburden complexity and sea water resistivity stratification on CSEM data. It is observed that the structural impacts are more pronounced on the static CSEM images than on its dynamic images. Then, coupled forward modelling of inline CSEM data and seismic amplitude data from a 3D fluid flow reservoir simulator is performed. The simulator serves the dual purpose of common oilfield in which production is aided by water injection, and of an interpretational constraint involving correlation of CSEM and seismic anomalies with injection and production activities at well locations (here called dynamic well tie). The time-lapse in-line CSEM amplitude change, modelled using dipole 1D, shows linear correlations of 64 to 68% with the change in water saturation. It is more responsive and consistently more linearly related to the change in water saturation than the seismic, despite the possible detrimental effects of reservoir heterogeneity. This is not surprising as seismic is responsive to a combination of changes in saturation and pressure. Coupled interpretation of seismic and CSEM modelled data show that time – lapse CSEM is a definite indicator of water saturation changes. For instance, when seismic softening due to rise in pressure masks increase in water saturation, or when seismic hardening due to pressure drop gives false increase in water saturation. The importance of brine mixing on the acoustic and electrical properties, during secondary and tertiary oil recovery, is examined. The seismic and EM rock physics are adjusted to cater for effective mixed brine resistivity, bulk modulus and bulk density, as functions of temperature and salinity for the injected and formation brines. Modelling of three scenarios of different combinations of injected and formation brines around the world, calibrated with a reference model in which brine properties were kept constant, indicate that EM is more responsive than the seismic, to the brine chemistry. Fluid flow modelling of sea water injection in the North Sea field shows that temperature effect is restricted to the vicinity of injector; while salinity effect travels farther from the injector along the water flooding front. The time-lapse EM could theoretically distinguish extreme brines. For instance, low salinity water injected into oil-wet reservoir with saline formation water; or moderately saline subsurface aquifer water injected into very saline formations of the Middle Eastern carbonates produced between -15 and 7% change in inline CSEM amplitude. In this thesis, 1D dipole forward modelling has generally highlighted values of EM in reservoir monitoring and management. Finally, repeat 3D EM data modelling produced time-lapse amplitude change of 0.3%, which is too small to be detected by the current CSEM acquisition. Thus, high precision EM field sensor will be required for practical application of 4D CSEM to reservoir monitoring. Only about 46% of this small 4D signature is interpretable for the change in transverse resistance of between -800Ωm2 and -1050Ωm2 (equivalent to resistivity reduction of between 13Ωm to 18Ωm). Broad qualitative information about the water flooded areas is provided, but fine detailed information about bypassed oil and early warning of water breakthrough could not be properly imaged

A Generalization to the Rastall Theory and Cosmic Eras

A generalized version for the Rastall theory is proposed showing the agreement with the cosmic accelerating expansion. In this regard, a coupling between geometry and the pressureless matter fields is derived which may play the role of dark energy responsible for the current accelerating expansion phase. Moreover, our study also shows that the radiation field may not be coupled to the geometry in a non-minimal way which represents that the ordinary energy-momentum conservation law is respected by the radiation source. It is also shown that the primary inflationary era may be justified by the ability of the geometry to couple to the energy-momentum source in an empty flat FRW universe. In fact, this ability is independent of the existence of the energy-momentum source and may compel the empty flat FRW universe to expand exponentially. Finally, we consider a flat FRW universe field by a spatially homogeneous scalar field evolving in potential $\mathcal{V}(\phi)$, and study the results of applying the slow-roll approximation to the system which may lead to an inflationary phase for the universe expansion.Comment: 11 page

Understanding the pro-technological properties of sourdough starter associations for bread flavour improvement

The use of sourdough has numerous benefits, including improvement of the sensory attributes of baked bread in terms of flavour, texture, volume, enhanced nutritional value and extended shelf life of bread. To achieve the desired sourdough performance and bread with optimal quality and improved flavour, it is essential to understand how the starter cultures behave in specific conditions. In a previous part of this research, the metabolic traits of lactic acid bacteria starters and yeast from the food company S.P.C. (S. Korea) were studied. This thesis aimed to explore the pro-technological properties of the selected starter associations of bacteria/yeast, i.e., Lactiplantibacillus plantarum + Fructilactibacillus sanfransciscensis + Saccharomyces cerevisiae (PSY) and Latilactobacillus curvatus + Levilactobacillus brevis + Saccharomyces cerevisiae (CBY). Consequently, analysis of acidification, proteolysis analysis (including free amino acids), and volatile compound profile were done. PSY and CBY grew at the expected cell density. pH of the sourdoughs fermented by PSY decreased along the same line and slower than that of CBY over the course of 24 h. PSY sourdough had the highest TTA value (11.12 ± 0.03 ml) and organic acid production (148.6 ± 2.4 mmol/kg and 25.1 ± 1.5 mmol/kg) than CBY sourdough TTA value (9.01 ± 0.11 ml) and organic acid production (110.6 ± 1.6 mmol/kg and 20.2 ± 0.9 mmol/kg). This shows PSY as having a relatively high capacity for producing acids during sourdough fermentation among the two associations. After assessing their proteolysis capabilities, PSY sourdough had a presumptively higher peptide content while CBY produced the highest free amino acid content (i.e., Orn having a potential repercussion on bread flavour). Several volatile compounds belonging to different chemical classes, such as acids, aldehydes, ketones, alcohols, esters, and other compounds, were produced by PSY and CBY. In PCA, the control sourdough had a distinctive volatile profile from PSY and CBY. Both PSY and CBY show much correlation with about 4% variation. Ethanol, acetic acid, benzene ethanol, 2(3H)-furanone, dihydro-5-pentyl showed their strongest influence on both sourdoughs as they are found in high amount. Finally, during sourdough fermentation, the associations performed in a desired way, and they showed differences in acidity and content of free amino acids that might have a strong influence on bread flavour. Less differences were observed in the volatile profile compounds of the two associations. Proper sensory analysis and consumer test (by the company) will be the most revealing of the differences observed in this experimental study