Intrusion detection and tolerance: A global scheme

Protecting implemented security mechanisms and trusting their output (e.g. log files) when the host, under which they are deployed, is compromised, is among the major challenges that have to be faced. To fulfil this need, recent advances in security have considered the design of storage-based intrusion detection system, which detect intrusions by looking at the low-level disk requests patterns. However, these systems neither tolerate intrusions, nor do they distinguish whether the disk requests are generated by legitimate or malicious processes; and consequently, they generate a lot of false negative and positive alerts. In this paper, we present a Cooperative Intrusion Detection and Tolerance System, called CIDTS, which takes advantage of the information that are available at the network, host operating system, and storage level to better detect intrusion attempts in their early stages, even when the host is compromised. To allow cooperation, the disk communication interface that transports requests between the storage level and the host level is extended to forward information about the processes that generate the request. The paper also provides intrusion tolerance capabilities and provides techniques to support investigation activities. Copyright © 2007 John Wiley & Sons, Ltd.     

Transmutation capabilities of the CERN Energy Amplifier System

Progress in particle accelerator technology makes it possible to use a proton accelerator to produce energy and to destroy nuclear waste efficiently. Energy Amplifier (EA) systems consist of a sub-critical fast neutron core driven by a proton accelerator. If well designed, they prevent any possible criticality accidents. It has been proposed to take advantage of this sub-criticality in order to use certain types of fuel with poor neutronic properties (for instance those with very small delayed neutron fractions). In this respect, they are particularly attractive for destroying, through fission, transuranic elements produced by present nuclear reactors. EA's could also transform efficiently and at minimal cost long-lived fission fragments using the concept of Adiabatic Resonance Crossing (ARC), an innovative method tested at CERN with the TARC experiment.     

Reply to the comments on "Local Overfitting Control via Leverages" in "Jacobian Conditioning Analysis for Model Validation" by I. Rivals and L. Personnaz

"Jacobian Conditioning Analysis for Model Validation" by Rivals and Personnaz in this issue is a comment on Monari and Dreyfus (2002). In this reply, we disprove their claims. We point to flawed reasoning in the theoretical comments and to errors and inconsistencies in the numerical examples. Our replies are substantiated by seven counterexamples, inspired by actual data, which show that the comments on the accuracy of the computation of the leverages are unsupported and that following the approach they advocate leads to discarding valid models or validating overfitted models.     

Strategies to lower methyl mercury concentrations in hydroelectric reservoirs and lakes: A review

Mercury (Hg) concentrations in fish in lakes are elevated due to increased global cycling of Hg. A special case of elevated Hg concentrations in fish occurs in new hydroelectric reservoirs because of increased rates of converting Hg in the environment into methyl mercury (MeHg). People and wildlife that eat fish from hydroelectric reservoirs have an elevated risk of accumulating too much MeHg. Demand for electrical energy is leading to the creation of new reservoirs. In 2005, Canada derived 60% of its electricity from hydroelectric reservoirs. As a result, hydroelectric companies and governing agencies are exploring strategies to lower MeHg contamination. Strategies may involve lowering the source of Hg before flooding, the rate of Hg methylation, or MeHg bioaccumulation and biomagnification. Possible strategies reviewed in this article include selecting a site to minimize impacts, intensive fishing, adding selenium, adding lime to acidic systems, burning before flooding, removing standing trees, adding phosphorus, demethylating MeHg by ultraviolet light, capping and dredging bottom sediment, aerating anoxic bottom sediment and waters, and water level management. A preventative strategy is to limit the flooded area, especially wetland areas. Flooded upland areas that contain less carbon produce MeHg for a shorter time than wetland areas. Run-of-the-river reservoirs contain lower MeHg concentrations than reservoirs that flood vast areas, at the cost of exporting MeHg downstream. Managing water levels to flush systems during times of peak MeHg production may have benefits for the reservoir, but also transports MeHg downstream. Intensive fishing can lower MeHg in food webs by increasing fish growth rate. Additions of selenium can lower MeHg bioaccumulation, but the mechanisms are not well established and excess selenium causes toxicity. Liming can lower fish Hg concentrations in lakes acidified with sulphuric and nitric acid. Burning before flooding can lower the production of MeHg, but MeHg bioaccumulation may increase. The most promising strategy will be one that is agreeable to all affected people.     

Viscosity,Swelling and Starch Leaching During the Early Stages of Pasting of Normal and Waxy Rice Starch Suspensions Containing Different Milk Protein Ingredients

The effects of three milk protein ingredients, sodium caseinate (NaCAS), whey protein isolate (WPI) and skim milk powder (SMP), on the swelling and leaching behaviour of normal and waxy rice starch solutions, during the early stages of pasting, were investigated. It was found that the swelling onset temperature for both starches was increased by NaCAS and SMP but was not affected by WPI. Furthermore, onset temperature determined by the swelling measurements was lower than the onset temperature determined from viscosity measurements. However, the calculated viscometric onset temperature, using the Maron‐Pierce equation and the results of the swelling measurements, was found to be in very good agreement with the measured viscometric onset temperature. This study also showed that the quantity of leached polysaccharides during the early stages of starch pasting was very small, indicating that significant leaching of polysaccharides during pasting primarily occurs after the break‐up of the sheared starch granules.     

Numerical Simulation of Taylor–Couette Flows with Rotating Outer Wall Using a Hybrid Spectral/Finite Element Method

Theoretical Foundations of Chemical Engineering - Taylor–Couette flow between independently rotating cylinders with a relatively small aspect ratio Γ = 2.4 has been investigated...     

A novel Pd-Cr2O3/CdS photocatalyst for solar hydrogen production using a regenerable sacrificial donor

Noble metals and transition-metal oxides are needed as cocatalysts for facilitating H₂ production over photocatalysts. Such cocatalysts are typically deposited as nanoparticles on the catalyst surface using impregnation or photodeposition methods, for which an activation treatment process is necessary. In this paper, we describe a facile method that utilizes a Pd-Cr₂O₃ nanocomposite cocatalyst at room temperature for the efficient production of H₂ without the need of an activation treatment process. The Pd-Cr₂O₃/CdS photocatalyst shows a higher hydrogen evolution rate than that of a plain Pd metal loaded catalyst. Formation of a composite structure appears to be an important reason for the increased performance of Pd-Cr₂O₃/CdS photocatalyst.