Low-power data-dependent 8/spl times/8 DCT/IDCT for video compression

Traditional fast discrete cosine transform (DCT)/inverse DCT (IDCT) algorithms have focused on reducing arithmetic complexity and have fixed run-time complexities regardless of the input. Recently, data-dependent signal processing has been applied to the DCT/IDCT. These algorithms have variable run-time complexities. A two-dimensional 8/spl times/8 low-power DCT/IDCT design is implemented using VHDL by applying the data-dependent signal processing concept onto the traditional fixed-complexity fast DCT/IDCT algorithm. To reduce power, the design is based on Loeffler's fast algorithm, which uses a low number of multiplications. On top of that, zero bypassing, data segmentation, input truncation and hardwired canonical sign-digit (CSD) multipliers are used to reduce the run-time computation, hence reducing the switching activities and the power. When synthesised using CMC 0.18 /spl mu/m 1.6 V CMOSP technology, the proposed FDCT/IDCT design consumes 8.94/9.54 mW, respectively, with a clock frequency of 40 MHz and a processing rate of 320 Msample/s. This design features lower dynamic power consumption per sample, i.e. it is more power-efficient than other previously reported high-performance FDCT/IDCT designs.     

Effect of dietary vitamin E supplementation on the colour and lipid stability of fresh, frozen and vacuum-packaged beef

The effects of dietary vitamin E supplementation on tissue α-tocopherol (α-Toc) levels and on the susceptibility of fresh, frozen and vacuum-packaged beef to lipid oxidation and colour deterioration were investigated. Friesian cattle were fed diets containing 20 (basal, n=5) or 2000 (supplemented, n=5) IU (α-tocopheryl acetate/kg feed/day for approximately 50 days prior to slaughter. α-Toc levels were higher (p<0.05) in muscles from supplemented animals than from those on a basal diet. Significant differences in α-Toc levels were also observed between muscles from different treatment groups, the order of the supplemented group was: M. psoas major (PM)>M. longissimus dorsi (LD)>M. gluteus medius (GM) (p<0.05), and in the basal group the order was: PM>GM>LD (p<0.05). Supplemented fresh, frozen and vacuum packed beef showed greater colour and lipid oxidative stability than meat from the basal group after 7 days retail display at 4°C (p<0.05). Thus, dietary (α-Toc supplementation appeared to retard metmyoglobin and TBARS formation in LD, GM and PM and increased the colour shelf life of these muscles.     

Elimination of vector parasites in finite element Maxwell solutions

The vector parasite problem is studied in the context of finite-element solutions of Maxwell's equations for driven boundary-value problems. An expanded weak form which combines the divergence equation with the conventional weak form of the double-curl equation is introduced. This form is related to penalty methods where the penalty or weighting factor varies with the dielectric constant. The resulting algebraic system is identical to the Galerkin-Helmholtz operator on homogeneous subregions. Normal and tangential boundary conditions arise in terms of the divergence and curl of the field on the boundary which can be reexpressed as equivalent charges and currents. Computational results show the occurrence of two distinct types of parasitic modes in driven problems and their elimination with the formulation presented. Practical observations concerning the conditions which provoke spurious modes in these problems are reported. Spurious solutions arise from improper or unphysical boundary conditions, and the importance of careful specification of boundary-value problems is illustrated. Most conceptual difficulties with boundary conditions per se are removed when hybrid methods are used to couple the interior finite-element solution to the exterior problem. which focuses attention on the physics of the source distribution     

Sensitivity of trigate MOSFETs to random dopant induced threshold voltage fluctuations

In this paper, we investigate random doping fluctuation effects in trigate SOI MOSFETs by solving the three-dimensional (3D) Poisson, drift-diffusion and continuity equations numerically. A single doping impurity atom is introduced in the undoped channel region of the device and the resulting shift of threshold voltage is measured from the simulated I–V characteristics. This enables the derivation of the threshold voltage shift (ΔV_TH) for any arbitrary location of the doping atom in the transistor. Based on an analysis of a sub-20 nm trigate MOSFET device, we find that the typical variation of V_TH per doping atom is a few tens of mV. Inversion-mode (IM) trigate devices are more sensitive to the doping fluctuation effects than accumulation-mode (AM) devices. The threshold voltage shift arising from doping fluctuations is maximum when the doping atom is near the center of the channel region, which means the original SOI film doping, the random contamination effects or any other impurity doping in the channel region is more important than atoms introduced in the channel by the S/D implantation process for sub-20 nm transistors.     

On the mechanics of functional asymmetry in bipedal walking

This paper uses two symmetrical models, the passive compass-gait biped and a five-link 3-D biped, to computationally investigate the cause and function of gait asymmetry. We show that for a range of slope angles during passive 2-D walking and mass distributions during controlled 3-D walking, these models have asymmetric walking patterns between the left and right legs due to the phenomenon of spontaneous symmetry-breaking. In both cases a stable asymmetric family of gaits emerges from a symmetric family of gaits as the total energy increases (e.g., fast speeds). The ground reaction forces of each leg reflect different roles, roughly corresponding to support, propulsion, and motion control as proposed by the hypothesis of functional asymmetry in able-bodied human walking. These results suggest that body mechanics, independent of neurophysiological mechanisms such as leg dominance, may contribute to able-bodied gait asymmetry.     

Time-domain integration of the Maxwell equations on finite elements

An explicit time-domain integration scheme is developed for finite-element spatial discretization of the Maxwell equations. A generalized wave equation is used in weak form, which is free of vector parasites when discretized on single C⁰ elements. The use of integral lumping renders the mass matrix diagonal with no necessary degradation in accuracy. The explicit method which results combines the economy of established finite-difference techniques with the geometric flexibility of finite elements. Test problems representative of practical hyperthermia applications show agreement with analytic and frequency-domain finite-element methods, and confirm scaling arguments on run-time and memory     

Normal mode nomenclature of quadrupole gyromagnetic waveguides

The normal mode nomenclature of quadruple gyromagnetic waveguides is reviewed. A perturbation and anisotropic formulation of the normal modes of this type of waveguide is given which is in keeping with previously published work. A closed-form formulation of the problem is described. The field distributions in this type of waveguide are shown to display a classic edge mode effect     

Specifying and proving properties of timed I/O automata using Tempo

Timed I/O automata (TIOA) is a mathematical framework for modeling and verification of distributed systems that involve discrete and continuous dynamics. TIOA can be used for example, to model a real-time software component controlling a physical process. The TIOA model is sufficiently general to subsume other models in use for timed systems. The Tempo Toolset, currently under development, is aimed at supporting system development based on TIOA specifications. The Tempo Toolset is an extension of the IOA toolkit, which provides a specification simulator, a code generator, and both model checking and theorem proving support for analyzing specifications. This paper focuses on the modeling of timed systems and their properties with TIOA and on the use of TAME4TIOA, the TAME (Timed Automata Modeling Environment) based theorem proving support provided in Tempo, for proving system properties, including timing properties. Several examples are provided by way of illustration.     

Continuous potential Maxwell solutions on nodal-based finiteelements

A nodal-based finite-element approach for computing electric fields in heterogeneous media is presented. The primary calculation is formulated in terms of continuous potentials, so that no special care is required on element assembly at dielectric interfaces. The resulting Galerkin weak-form matrices exhibit the special Helmholtz structure, which guarantees the absence of parasitic solutions in driven problems with physically well-posed boundary conditions. The enhanced sparsity of the Helmholtz form mitigates the extra coupling effort associated with introduction of a fourth degree of freedom relative to direct E solution. E can be extracted from the computed potentials as a postprocessing step either at nodal positions or element centroids. Solutions obtained with this approach for several benchmark and practical problems are shown to be parasite-free and essentially indistinguishable from previously reported direct E computations     

Biochemical activity of centipedegrass against fall armyworm larvae

Centipedegrass,Eremochloa ophiuroides (Munro) Hack, severely inhibits growth of the fall armyworm larva,Spodoptera frugiperda (J.E. Smith). Fresh centipedegrass extracts and extract fractions were deposited on Celufil, incorporated into meridic-based diets and bioassayed against neonate larvae of the fall armyworm in the laboratory. The methanol extract (F₁) caused the greatest reduction in larval weight. When F₁, was partitioned between méthylene chloride and water, the activity was transferred to the water-soluble fraction (F₅), which, when further fractionated using preparative C-18 reverse-phase chromatography, yielded active F₇ and F₈ fractions. Gas chromatograph-mass spectrometry and high-pressure liquid chromatography (HPLC) showed F₇ to be 95% caffeoylquinic acids with chlorogenic acid as the major constituent. HPLC analysis of F₈ revealed maysin [2-O- -L-rhamnosyl-6-C-(6-deoxy-Xylo-hexos-4-ulosyl)luteolin] and other luteolin derivatives. Chlorogenic acid and other caffeoylquinic acids, maysin, and other luteolin derivatives are the major factors responsible for the antibiotic resistance of centipedegrass to larvae of the fall armyworm.