Appearance-based face recognition and light-fields

Arguably the most important decision to be made when developing an object recognition algorithm is selecting the scene measurements or features on which to base the algorithm. In appearance-based object recognition, the features are chosen to be the pixel intensity values in an image of the object. These pixel intensities correspond directly to the radiance of light emitted from the object along certain rays in space. The set of all such radiance values over all possible rays is known as the plenoptic function or light-field. In this paper, we develop a theory of appearance-based object recognition from light-fields. This theory leads directly to an algorithm for face recognition across pose that uses as many images of the face as are available, from one upwards. All of the pixels, whichever image they come from, are treated equally and used to estimate the (eigen) light-field of the object. The eigen light-field is then used as the set of features on which to base recognition, analogously to how the pixel intensities are used in appearance-based face and object recognition.     

Securing the Operating System: Does lesser-known mean less at risk? Is the OS an example of security though obscurity?

It is no secret that Microsoft Windows NT is the hacker’s favourite Operating System (OS). According to defacement-tracking site Attrition.org, (www.Attrition.org) Windows NT received 54.41% of all recorded OS attacks between August 1999 and April 2001. In stark contrast, some of the lesser-known Operating Systems made up for as little as 0.1% of all OS attacks. However, despite the huge difference in the quantity of attacks, companies that employ the lesser-known systems may be at greater risk…     

2D vs. 3D Deformable Face Models: Representational Power,Construction, and Real-Time Fitting

Model-based face analysis is a general paradigm with applications that include face recognition, expression recognition, lip-reading, head pose estimation, and gaze estimation. A face model is first constructed from a collection of training data, either 2D images or 3D range scans. The face model is then fit to the input image(s) and the model parameters used in whatever the application is. Most existing face models can be classified as either 2D (e.g. Active Appearance Models) or 3D (e.g. Morphable Models). In this paper we compare 2D and 3D face models along three axes: (1) representational power, (2) construction, and (3) real-time fitting. For each axis in turn, we outline the differences that result from using a 2D or a 3D face model.     

High mobility p-channel organic field effect transistors on flexible substrates using a polymer-small molecule blend

Organic field effect transistors have been fabricated on poly(ethylene terephthalate) film substrates with excellent operating characteristics and maximum mobilities of 1.1 cm²/(V s). The semiconductor was a solution processible blend of 6,13-bis(triisopropyl silylethynyl) pentacene and a poly(triaryl amine) used to combine the favourable properties of small molecules and polymers. We have demonstrated that such systems are a good candidate for flexible organic electronics and that the surface energy of the substrate plays a key role in controlling the morphology of the semiconductor film.     

Biosynthesis of galactomannan in the endosperms of developing fenugreek (Trigonella foenum-graecum L.) and guar (Cyamopsis tetragonoloba [L.] Taub.) seeds

The biosynthesis of galactomannan in vitro has been demonstrated conclusively using particulate enzyme preparations from the developing endosperms of fenugreek and guar and the sugar nucleotides GDP-D-mannose and UDP-D-galactose. Furthermore the mannose: galactose (man:gal) ratio in the products formed in vitro has been manipulated. These results are discussed in the context of possible mechanisms for the control of man:gal ratio in vivo.     

Computational model of three-dimensional cardiac electromechanics

We coupled a continuum model of impulse propagation with a three-dimensional model of regional ventricular mechanics. Equations for action potential propagation, myofilament activation and active contraction were solved in an anatomically detailed finite element model of canine left and right ventricular geometry, muscle fiber architecture and Purkinje fiber network anatomy. Finite element equations for time-dependent excitation and recovery variables were assembled using a collocation method and solved using adaptive Runge-Kutta integration. Resting tissue mechanics were modeled as nonlinear, orthotropic and hyperelastic. A Windkessel model for arterial impedance was coupled to ventricular pressure and volume to compute hemodynamic boundary conditions during ejection. Ventricular volume constraints were imposed during the isovolumic phases. This model showed good agreement in the time course of regional systolic strains with experimental measurements during normal sinus rhythm and demonstrates the importance of the Purkinje fiber system in determining the mechanical activation sequence.     

The Influence of Film Morphology in High‐Mobility Small‐Molecule:Polymer Blend Organic Transistors

Organic field‐effect transistors (OFETs) based upon blends of small molecular semiconductors and polymers show promise for high performance organic electronics applications. Here the charge transport characteristics of high mobility p‐channel organic transistors based on 2,8‐difluoro‐5,11‐bis(triethylsilylethynyl) anthradithiophene:poly(triarylamine) blend films are investigated. By simple alteration of the film processing conditions two distinct film microstructures can be obtained: one characterized by small spherulitic grains (SG) and one by large grains (LG). Charge transport measurements reveal thermally activated hole transport in both SG and LG film microstructures with two distinct temperature regimes. For temperatures >115 K, gate voltage dependent activation energies (E_A) in the range of 25–60 meV are derived. At temperatures <115 K, the activation energies are smaller and typically in the range 5–30 meV. For both film microstructures hole transport appears to be dominated by trapping at the grain boundaries. Estimates of the trap densities suggests that LG films with fewer grain boundaries are characterized by a reduced number of traps that are less energetically disordered but deeper in energy than for small SG films. The effects of source and drain electrode treatment with self‐assembled monolayers (SAMs) on current injection is also investigated. Fluorinated thiol SAMs were found to alter the work function of gold electrodes by up to ～1 eV leading to a lower contact resistance. However, charge transport analysis suggests that electrode work function is not the only parameter to consider for efficient charge injection.     

SwarmDock and the Use of Normal Modes in Protein-Protein Docking

Here is presented an investigation of the use of normal modes in protein-protein docking, both in theory and in practice. Upper limits of the ability of normal modes to capture the unbound to bound conformational change are calculated on a large test set, with particular focus on the binding interface, the subset of residues from which the binding energy is calculated. Further, the SwarmDock algorithm is presented, to demonstrate that the modelling of conformational change as a linear combination of normal modes is an effective method of modelling flexibility in protein-protein docking.     

The limited role for Carbon Capture and Storage (CCS) technologies in a sustainable Australian energy future

There is considerable debate regarding the potential role of Carbon Capture and Storage (CCS) technologies in reducing Australia's greenhouse emissions. The latest climate change science suggests that major (60% or more by 2050), rapid (peaking within 20 years) cuts in global emissions may be required to avoid dangerous climate change. There are a number of existing abatement options including energy efficiency, various renewable energy technologies, nuclear power and fuel switching to natural gas; as well as emerging options including CCS. We outline a simple technology assessment framework for policymakers to evaluate these different options given the climate change imperative. This framework includes technology status, delivered energy services, present and possible future costs, potential scale of abatement, potential speed of deployment and other possible social outcomes. Application of this framework to CCS suggests that it should be considered as a promising, but still somewhat unproven, option that potentially offers very significant abatement potential and good integration into the existing energy industry. There are, however, some outstanding questions regarding its effectiveness and safety, its abatement is likely to come at significant cost, and it is unlikely to be able to make a significant contribution for well over a decade. The Australian policy implications are that while government support for R&D and Demonstration of CCS is appropriate and should in our view be expanded, the major priority should be to support greater deployment of existing abatement options including energy efficiency, efficient gas-fired generation and cogeneration and renewable energy. Such policy support is noticeably lacking at present.