Malware and steganography in hard disk firmware

The hard disk drive remains the most commonly used form of storage media in both commercial and domestic computer systems. These drives can contain a vast range of data both of personal value and commercial significance. This paper focuses on two key areas; the potential for the drive operation to be impacted by malicious software and the possibility for the drive firmware to be manipulated to enable a form of steganography. Hard drive firmware is required for the correct operation of the disk drive in particular for dealing with errors arising due to natural wear as the drive ages. Where an area of the drive becomes unreliable due to wear and tear, the disk firmware which monitors the reliability of data access will copy the data from the failing area to a specially designated reserved area. The firmware remaps this data shift so the old data area and the original copy of the data are no longer accessible by the computer operating system. There are now a small number of commercially available devices, intended for data recovery, which can be used to modify the hard drive firmware components. This functionality can be used to conceal code on the disk drive, either as a form of steganography or to potentially include malicious code with the intention to infect or damage software or possibly system hardware. This paper discusses the potential problem generated by firmware being manipulated for malicious purposes.     

Carlisle 2005 urban flood event simulation using cellular automata-based rapid flood spreading model

In this study, we propose a new method to apply the rapid flood spreading model (RFSM) using cellular automata (CA) to multiple inflows of Carlisle, UK. The purpose of the RFSM is to generate predictions of water depth and flood extent using less computer resource than required by two-dimensional shallow water equation models (SWEMs). To be useful the RFSM must produce predictions that are comparable with those obtained from SWEMs. This paper reports a validation data available to the date on an urban flood, collected in January 2005 after a major event in the city of Carlisle, UK. This demonstrates an agreement between the proposed RFSM and measured data.     

Potential of nuclear quadrupole resonance in pharmaceutical analysis

Nuclear quadrupole resonance is a radio frequency (rf) spectroscopic technique, closely related to NMR, which can be used to detect signals from solids containing nuclei with spin quantum number >1/2. It is nondestructive, highly specific and noninvasive, requires no static magnetic field, and as such is currently used in the detection of explosives and narcotics. Recent technological advances in pulsed NQR methods have shortened detection times, eliminated spurious signals, and enhanced the sensitivity of detection of 14N frequencies, which lie in the low rf range of 0.4-6 MHz, encouraging a wider range of "real world" applications. This Perspective highlights some of the advantages of NQR, the applications in which it could be used, such as the quantification of pharmaceuticals and the identification of polymorphs. Other roles could include detection, analysis, and quality control of pharmaceuticals at all stages of manufacture. Finally, recent advances which enhance even further the sensitivity of detection will be discussed.     

Dispersion analysis and computational efficiency of elastic lattice methods for seismic wave propagation

Discrete particle methods or elastic lattice methods represent a 3D elastic solid by a series of interconnected springs arranged on a regular lattice. Generally, these methods only consider nearest neighbour interactions, i.e. they are first-order in space. These interconnected springs interacted through a force term (Hooke's Law for an elastic body), which when viewed on a macroscopic scale provide a numerical solution for the elastodynamic wave equations. Along with solving the elastodynamic wave equations these schemes are capable of simulating elastic static deformation. However, as these methods rely on nearest neighbour interactions they suffer from more pronounced numerical dispersion than traditional continuum methods. By including a new force term, the numerical dispersion can be reduced while keeping the flexibility of the nearest neighbour interaction rule. We present results of simulations where the additional force term reduces the numerical dispersion and increases the accuracy of the elastic lattice method solution. The computational efficiency and parallel scaling of this method on multiple processors is compared with a finite-difference solution to assess the computational cost of using this approach for simulating seismic wave propagation. We also show the applicability of this method to modelling seismic propagation in a complex Earth model.     

Production of a carotenoid-rich product by alginate entrapment and fluid-bed drying of Dunaliella salina

A new carotenoid-rich product was formed by entrapment of Dunaliella salina in calcium alginate beads of different alginate concentrations, followed by drying in a fluid-bed dryer. The drying process yielded β-carotene recoveries of between 79 and 89% and produced a change in the 9-cis/all-trans ratio of β-carotene isomers. The carotenoid stability of the product was dependant on both the storage conditions and alginate content (range 3·3–7·3 g litre⁻¹) of the beads. In the presence of light and oxygen total carotenoid degraded following a first order kinetic model with degradation constants between 0·016 and 0·039 days⁻¹, with the lowest degradation occurring with the lowest alginate concentration. Product stored in the dark and flushed with nitrogen produced first-order degradation constants of 0·012 and 0·020 days⁻¹ for the two higher alginate concentrations; that with the lowest alginate content showed no noticeable degradation after 58 days storage. During storage, the 9-cis isomer was significantly more unstable showing a relative loss under all conditions, degrading almost completely when stored in the presence of light and oxygen and reaching an equilibrium ratio with the all-trans isomer when stored in the dark and flushed with nitrogen. © 1998 SCI.     

Estimating distributed anatomical connectivity using fast marching methods and diffusion tensor imaging

A method is presented for determining paths of anatomical connection between regions of the brain using magnetic resonance diffusion tensor information. Level set theory, applied using fast marching methods, is used to generate three-dimensional time of arrival maps, from which connection paths between brain regions may be identified. The method is demonstrated in the normal brain and it is shown that major white matter tracts may be elucidated and that multiple connections and tract branching are allowed. Maps of connectivity between brain regions are also determined. Four options are described for estimating the degree of connectivity between regions.     

Fabrication of nanopore array electrodes by focused ion beam milling

Single nanopore electrodes and nanopore electrode arrays have been fabricated using a focused ion beam (FIB) method. High aspect ratio pores (approximately 150-400-nm diameter and 500-nm depth) were fabricated using direct-write local ion milling of a silicon nitride layer over a buried platinum electrode. This local milling results in formation of a recessed platinum electrode at the base of each nanopore. The electrochemical properties of these nanopore metal electrodes have been characterized by voltammetry. Steady-state voltammograms were obtained for a range of array sizes as well as for single nanopore electrodes. High-resolution scanning electron microscopy imaging of the arrays showed that the pores had truncated cone, rather than cylindrical, conformations. A mathematical model describing diffusion to an electrode located at the base of a truncated conical pore was developed and applied to the analysis of the electrode geometries. The results imply that diffusion to the pore mouth is the dominant mass transport process rather than diffusion to the electrode surface at the base of the truncated cone. FIB milling thus represents a simple and convenient method for fabrication of prototype nanopore electrode arrays, with scope for applications in sensing and fundamental electrochemical studies.