Security management of mutually trusted domains through cooperation of defensive technologies

A number of defensive technologies have been proposed for the prevention of security threats. However, these defensive technologies are implemented independently without cooperation among various network domains. In this paper, different administrative networks are leagued to form a federative network environment called a trusted domain. From the perspective of a network manager, there is a need to integrate diverse technologies into an effective defensive system among mutually trusted domains. An imperative task for security management is to put in place a shared defensive mechanism, or protective shield, for multiple domains. A cooperative approach to provide such a shared defensive system is presented with integration of both intra‐domain and inter‐domain defensive mechanisms. The simulation results show that, through sharing the defensive information, the firewall system can successfully detect and filter the repeated intrusions. Copyright © 2008 John Wiley & Sons, Ltd.     

The oxidation behavior of an Fe61B15Zr8Mo7Co5Y2Cr2 bulk metallic glass at 650 °C in various oxygen-containing environments

The oxidation behavior of an Fe₆₁B₁₅Zr₈Mo₇Co₅Y₂Cr₂ bulk metallic glass (Fe7-BMG) was investigated in three oxygen-containing atmospheres over the oxygen partial pressure range of 10³–10⁵ Pa at 650 °C. The oxidation kinetics of the Fe7-BMG followed the parabolic rate law in all cases, indicating that solid-state diffusion is the rate-controlling step during oxidation. The oxidation rate constants (k_p values) increased with increasing oxygen partial pressure, implying a typical scaling behavior with a p-type semiconductivity. Duplex scales formed on the Fe7-BMG consisted of an outer layer of mostly iron oxides (Fe₂O₃/Fe₃O₄) and minor amounts of B₂O₃, and a heterophasic inner layer of mostly tetragonal-ZrO₂ (t-ZrO₂) intermixed with non-oxidized intermetallic phases.     

Impact of preanneal process on threshold voltage of MOS transistors for trench DRAM

As the first step of DRAM manufacture, preanneal process plays an important role in determining the threshold voltage variation. It is found that the higher trans-1,2-dichloroethene flow in pad oxide growth and the higher nitrogen flow in high-temperature annealing step would respectively engender a lower boron segregation coefficient and higher nitridation of the oxide, both modify the boron distribution in the substrate and consequently the behavior of the threshold voltage. As the feature size of DRAM devices enter nanometer regime, besides gate oxidation, ion implantation and related thermal processes, the impact of preanneal process condition should be prudentially taken into consideration for rigorous control of the threshold voltage in the advanced DRAM production.     

Properties of Silicon Nitride–Molybdenum Disilicide Particulate Ceramic Composites

The physical and mechanical properties of hot-pressed Si₃N₄–MoSi₂ particulate composites containing 15 and 30 vol% MoSi₂ were studied. The average room-temperature four-point bend strength, fracture toughness, and electrical resistivity are 522 MPa, 3.6 MPa·√m, and 6.3 × 10⁵Χ·cm for the 15 vol% MoSi₂ composite, and 487 MPa, 5.3 MPa·√m, and 0.31 Ω·cm for the 30 vol% MoSi₂ composite. The mechanical properties of the composites are very close to those of hot-pressed Si₃N₄ ceramics. The high electrical conductivity of the 30 vol% MoSi₂ composite was attributed to the percolation effect of MoSi₂ particles. Parabolic oxidation behaviors were observed for the 30 vol% MoSi₂ composite during the 1200°C long-term oxidation experiments.     

A study of diffusion in poly(ethyleneglycol)-gelatin based semi-interpenetrating networks for use in wound healing

Semi-interpenetrating networks (sIPNs) designed to mimic extracellular matrix via covalent crosslinking of poly(ethylene glycol) diacrylate in the presence of gelatin have been shown to aid in wound healing, particularly when loaded with soluble factors. Ideal systems for tissue repair permit an effective release of therapeutic agents and flow of nutrients to proliferating cells. Appropriate network characterization can, consequently, be used to convey an understanding of the mass transfer kinetics necessary for materials to aid in the wound healing process. Solute transport from and through sIPNs has not yet been thoroughly evaluated. In the current study, the diffusivity of growth factors and nutrients through the polymeric system was determined. Transport of keratinocyte growth factor was modeled by treating the sIPN as a plane sheet into which the protein was loaded. The diffusion coefficient was determined to be 4.86 × 10⁻⁹ ± 1.86 × 10⁻¹² cm²/s. Glucose transport was modeled as flow through a semi-permeable membrane. Using lag-time analysis, the diffusion coefficient was calculated to be 2.25 × 10⁻⁶ ± 1.98 × 10⁻⁷ cm²/s. The results were evaluated in conjunction with previous studies on controlled drug release from sIPNs. As expected from Einstein-Stokes equation, diffusivity decreased as molecular size increased. The results offer insight into the structure-function design paradigm and show that release from the polymeric system is diffusion controlled, rather than dissolution controlled.     

Grand Coulee Dam 70 Years Later: What Can We Learn?

This paper presents key findings from a case study on the Grand Coulee Dam conducted by the authors for the World Commission on Dams. The analysis demonstrates that the distribution of project benefits has been tilted in favour of irrigation interests and hydroelectric power users and that the project's major cost bearers have been riparian-based indigenous tribes of the Upper Columbia River. The study identifies lessons learned that are applicable to many large multi-purpose water resources development projects. Within the paper, the impacts of the following factors are discussed: low stakeholder participation in decision making; absence of just compensation to Native Americans and Canadian First Nations adversely affected by the loss of fishery resources; modernization of agricultural technology; differing stakeholder perceptions of project costs and benefits; and changes in values attached to anadromous fish. The lessons highlight the need for careful, broad-based a priori assessments of the irreversible and cumulative impacts of large water resources development projects as well as planned re-evaluations of water allocations and project operations.     

Terahertz Microchip for Illicit Drug Detection

To accurately detect minute amounts of substances without disturbing the surroundings of target molecules has been a major goal in bioanalytical technology. Here by integrating an optoelectronic terahertz (THz) microsource into a glass-substrated microchip within the near-field distance, we demonstrate a compact, label-free, noninvasive, and sensitive microbiosensing system with low-power consumption. The demonstrated THz microchip allows us to locally specify various illicit drug powders with weights of nanograms, with a promising future for rapid identification of the static status or even the dynamics of various biomolecules     

Robustness of periodic trajectories

A robustness problem for periodic trajectories is considered. A nonautonomous system with a periodic solution is given. The problem is to decide whether a stable periodic solution remains in a neighborhood of the nominal periodic solution when the dynamics of the system is perturbed. The case with a structured dynamic perturbation is considered. This makes the problem a nontrivial generalization of a classical problem in the theory of dynamical systems. A solution to the robustness problem will be obtained by using a variational system obtained by linearizing the system dynamics along a trajectory, which is uncertain but within the prespecified neighborhood of the nominal trajectory. This gives rise to robustness conditions that can be solved using integral quadratic constraints for linear time periodic systems.     

Anomalous Pr Ordering and Structural Analysis for Oxygenated Tetragonal 1212 Compound Pr1.5Ba1.5Cu3O7.2

Magnetic measurement and powder X-ray Rietveld analysis are performed on oxygenated Pr _1.5 Ba _1.5 Cu ₃ O _7.2 cuprate. This tetragonal compound with lattice parameters a = 0.38916 nm and c = 1.16177 nm is found to form the TlBa ₂ CaCu ₂ O ₇ 1212-type structure when written as Cu[Ba _1.5 Pr _0.5 ]PrCu ₂ O _7.2. Low temperature magnetic data indicate that anomalous Pr order temperature T _N (Pr) decreases from 18 K for orthorhombic PrBa ₂ Cu ₃ O _6.9 to 10.5 K for Pr _1.5 Ba _1.5 Cu ₃ O _7.2. The increasing Pr-O bond length with decreasing T _N indicates that Pr ordering is closely correlated with the wave function overlap between Pr-4f orbital and O-2p orbital in the CuO ₂ bi-layers.