Smart card security evaluation: Community solutions to intractable problems

Evaluation of smart card security faced seemingly intractable problems of consistency and repeatability in its early days. The deeply specialised technologies, large parameter spaces for attacks, and the evolving attack types and countermeasures mean that the scope for variation in evaluation practice, and hence in evaluation conclusions, is potentially huge. The situation is further complicated by the fact that countermeasures against some types of attacks depend on both hardware and software, but there is also a need to evaluate hardware without specific software present at the time of evaluation. Stakeholders in the smart card world have formed a Community that has successfully created and applied interpretation of Common Criteria (ISO 15408) to deal with this problem and to achieve international mutual recognition of evaluation results. This paper discusses examples of the smart card security problem in order to illustrate some of the difficulties, and describes some of the interpretation that has been defined for rating the difficulty of an attack via calculation of an attack potential. It also considers the nature of the Community that has enabled the interpretation to be both defined and put into practice successfully.     

Tail pinching-induced hindlimb movements are suppressed by clonidine in spinal cord injured mice.

Experiments in completely spinal cord transected (Tx) cats have provided compelling evidence that clonidine combined with tail stimulation can promote locomotor function recovery. However, clonidine has generally failed to induce locomotor activity in other comparable animal models suggesting the existence of species- or condition-specific effects. This study aimed at investigating the effects of clonidine administered (0.25 or 5.0 mg/kg, i.p.) in mice during tail pinching in early (6-7 days post-Tx) or late (41-42 days post-Tx) paraplegic animals (Th9/10 level). Comparisons were made with the effects induced by 8-OH-DPAT (1.0 mg/kg, i.p.), a 5-HT1A/7 receptor agonist known to display prolocomotor effects. Clonidine with or without tail pinching failed to induce hind limb movements and even suppressed the frequency of spontaneously occurring nonlocomotor (NLM) and locomotor-like movements (LM) whereas tail pinching alone (prior to clonidine administration) increased the frequency of spontaneous movements specifically in late chronic animals. In turn, 8-OH-DPAT clearly induced hind limb movements that remained relatively unchanged during tail pinching. Altogether, the results suggest that the prolocomotor effects of clonidine reported elsewhere must depend upon stimuli or factors that remain to be identified. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Multiple states, topology and bifurcations of natural convection in a cubical cavity

A numerical investigation has been conducted to explore the steady nonlinear low Prandtl number flow/thermal transition in a differentially heated cubic cavity. For small values of Rayleigh number (Ra), it is observed that initially there was only one symmetric steady-state solution. When the Ra was amplified, the system bifurcates from one fixed-point solution to the two stationary solutions, namely, Mode I and Mode II pitchfork bifurcations. This is due to the symmetric nature existing along the vertical and diagonal planes. The flow structure in the present nonlinear system consists of a pair of asymmetric counter-rotating helical cells in a double helix structure, foliated with invariant helically symmetric surfaces containing the fibre-like fluid particle orbits. Also the evolution of different symmetry-breaking orientations on the transverse and diagonal planes of the cavity was noticed. In the Mode I orientation a symmetric vortex coreline was observed. However, in the Mode II orientation a pair of anti-symmetric vortex corelines was observed. Detailed topological study was made based on the rule of Hunt and the structural stability criteria. Also the simulated results were corroborated with numerical evidence. The existence of the critical Ra values was ascertained with the aid of the predicted L₂-error norms, thermal/flow iso-contours and streamlines. The route of Mode I orientation was made of the alternate symmetric and asymmetric flows as Ra was augmented.     

Closed channel fabrication using micromolding of metallic glass

Casting and molding are attractive options for low cost mass production. Metallic glasses may avoid many of the problems associated with micromolding of metals such as high temperatures and pressures, costly mold production, and shrinkage due to crystallization. In this study, we have produced 100 μm², enclosed channels in metallic glass using a novel multilayer Si stack micromolding process. Scanning electron microscope (SEM) images of the enclosed channels are provided to verify that the closed channels extended through the sample.     

A Novel Three-Dimensional Hydrogel-Based Microarray Platform

Three dimensional (3D) microarrays utilizing hydrogel matrixes are becoming increasingly attractive as a desired format for bio-analysis. These materials offer significant advantages as a scaffolding for capture agents over more conventional two dimensional (2D) printed formats in both captures per site and the ability to provide an environment more closely resembling that of a free solution. Biocept has developed a flexible three dimensional polyethylene glycol (PEG) polymer based platform suitable for a variety of biological assays. This novel approach is simple, biocompatible and provides a high degree of reproducibility and very low variability in the final array.     

Nontexture Inpainting by Curvature-Driven Diffusions

Inpainting is an image interpolation problem, often referring to interpolations over large-scale missing domains. In this paper, guided by the connectivity principle of human visual perception, we introduce a nonlinear PDE inpainting model based upon curvature-driven diffusions for nontexture images. This third-order PDE model improves the second-order total variation inpainting model introduced earlier by Chan and Shen (SIAM J. Appl. Math., in press, 2001). Computational schemes and digital examples are given.