Texture mapping in a distributed environment

This paper presents a tool for texture mapping in a distributed environment. A parallelization method based on the master-slave model is described. The purpose of this work is to lower the image generation time in the complex 3D scenes synthesis process. The experimental results concerning the speedup of texture mapping algorithm are also presented.

Interpolatory methods for H∞\mathcal{H}_\infty model reduction of multi-input/multi-output systems

We develop here a computationally effective approach for producing high-quality $\mathcal{H}_\infty$-approximations to large scale linear dynamical systems having multiple inputs and multiple outputs (MIMO). We extend an approach for $\mathcal{H}_\infty$ model reduction introduced by Flagg, Beattie, and Gugercin for the single-input/single-output (SISO) setting, which combined ideas originating in interpolatory $\mathcal{H}_2$-optimal model reduction with complex Chebyshev approximation. Retaining this framework, our approach to the MIMO problem has its principal computational cost dominated by (sparse) linear solves, and so it can remain an effective strategy in many large-scale settings. We are able to avoid computationally demanding $\mathcal{H}_\infty$ norm calculations that are normally required to monitor progress within each optimization cycle through the use of "data-driven" rational approximations that are built upon previously computed function samples. Numerical examples are included that illustrate our approach. We produce high fidelity reduced models having consistently better $\mathcal{H}_\infty$ performance than models produced via balanced truncation; these models often are as good as (and occasionally better than) models produced using optimal Hankel norm approximation as well. In all cases considered, the method described here produces reduced models at far lower cost than is possible with either balanced truncation or optimal Hankel norm approximation

Optimisation in behavioural synthesis using hierarchical expansion: module ripping

During behavioural synthesis, an abstract functional description of a system is mapped automatically onto a physical structure. In a competitive setting, this mapping will be highly optimised - the dataflow is re-arranged, units and registers are multiplexed and so on - to deliver a final structure that meets some overall user supplied specification. Ultimately, however, the physical functional units are drawn from some predefined (human designed) library - these may be thought of as the leaf-level modules in the design hierarchy. Design re-use and increasing sophistication of module libraries inevitably leads to leaf modules becoming larger and more complex. As these modules are, by definition, atomic, a synthesis system is unable to capitalise on any internal similarities the leaf modules may possess. This paper describes the design, construction and effects of using a hierarchically defined module library. The set of leaf-level modules made available to the synthesis environment is conventional - add, subtract, multiply and so on - but the optimiser is capable of ?ripping apart? these modules to manipulate their inner structures. Two advantages accrue from this technique: (1) it is possible to optimise behavioural designs far more effectively, with up to a 65% reduction in area, and a 46% reduction in delay reported, and (2) it is possible to build library modules that have tightly controllable internal timing relationships. This is essential when designing systems that communicate externally via low-level protocols, but behavioural synthesis, by its very nature, usually distorts timing information. Using this technique, it is possible to create ?islands of fixed timing? embedded in the synthesised design

Tracing Ghost Cavities with Low Frequency Radio Observations

We present X-ray and multi-frequency radio observations of the central radio sources in several X-ray cavity systems. We show that targeted radio observations are key to determining if the lobes are being actively fed by the central AGN. Low frequency observations provide a unique way to study both the lifecycle of the central radio source as well as its energy input into the ICM over several outburst episodes.Comment: 6 pages, 4 figures, To appear in the Proceedings of "Heating vs. Cooling in Galaxies and Clusters of Galaxies", eds. H. Boehringer, P. Schuecker, G. W. Pratt & A. Finoguenov (ESO Astrophysics Symposia, Springer-Verlag), Garching (Germany), August 200

Investigating the mechanical response of paediatric bone under bending and torsion using finite element analysis

Fractures of bone account 25% of all paediatric injuries (Cooper et al. in J Bone Miner Res 19:1976-1981, 2004. https://doi.org/10.1359/JBMR.040902 ). These can be broadly categorised into accidental or inflicted injuries. The current clinical approach to distinguish between these two is based on the clinician's judgment, which can be subjective. Furthermore, there is a lack of studies on paediatric bone to provide evidence-based information on bone strength, mainly due to the difficulties of obtaining paediatric bone samples. There is a need to investigate the behaviour of children's bones under external loading. Such data will critically enhance our understanding of injury tolerance of paediatric bones under various loading conditions, related to injuries, such as bending and torsional loads. The aim of this study is therefore to investigate the response of paediatric femora under two types of loading conditions, bending and torsion, using a CT-based finite element approach, and to determine a relationship between bone strength and age/body mass of the child. Thirty post-mortem CT scans of children aged between 0 and 3 years old were used in this study. Two different boundary conditions were defined to represent four-point bending and pure torsional loads. The principal strain criterion was used to estimate the failure moment for both loading conditions. The results showed that failure moment of the bone increases with the age and mass of the child. The predicted failure moment for bending, external and internal torsions were 0.8-27.9, 1.0-31.4 and 1.0-30.7 Nm, respectively. To the authors' knowledge, this is the first report on infant bone strength in relation to age/mass using models developed from modern medical images. This technology may in future help advance the design of child, car restrain system, and more accurate computer models of children

SZTAKI desktop grid: building a scalable, secure platform for desktop grid computing

In this paper we present a concept how separate desktop grids can be used as building blocks for larger scale grids by organizing them in a hierarchical tree. We describe an enhanced security model which satisfies the requirements of the hierarchical setup and is aimed for real-world deployment

Fabrication Of Smooth Diamond Films On Sio2 By The Addition Of Nitrogen To The Gas Feed In Hot-filament Chemical Vapor Deposition

The morphology of small roughness diamond films deposited onto thermally oxidized silicon substrates by a process of anisotropic crystalline growth induced by nitrogen in a hot-filament chemical vapor deposition (CVD) reactor was investigated. Square plates of low roughness were obtained on the top surface of the diamond films. Scanning electron microscopy (SEM), atomic force microscopy (AFM) and micro-Raman spectroscopy indicated films made up of good quality. The films possessed a large number of defects due to substitutional nitrogen. Planar defects were created due to large amount of nitrogen introduced in the CVD process. Substitutional nitrogen provoked lateral vacancies that have a catalytic effect on the lateral rate of diamond growth.19410521056Angus, J.C., Hayman, C.C., (1988) Science, 241, p. 913Yarborough, W.A., Messier, R., (1990) Science, 241, p. 688Derjaguin, B.V., Fedoseev, D., (1977) Izd., , Nauka, Moscow, Chap. 4Tankala, K., DebRoy, T., (1992) J. Appl. Phys., 72, p. 712Okano, K., Koizumi, S., Silva, S.R.P., Amaratunga, G.A.J., (1996) Nature (London), 381, p. 140Liao, X.Z., Zhang, R.J., Lee, C.S., Tong Lee, S., Lam, Y.W., (1997) Diamond Relat. Mater., 6, p. 521Dos Santos Filho, S.G., Hasenack, C.M., Lopes, M.C.V., Baranauskas, V., (1995) Semicond. Sci. Technol., 10, p. 990Jin, S., Moustakas, T.D., (1994) Appl. Phys. Lett., 65, p. 403Locher, R., Wild, C., Herres, N., Behr, D., Koidl, P., (1996) Appl. Phys. Lett., 65, p. 759Walker, J.E., (1979) Rep. Prog. Phys., 42, p. 42Evans, T., Rainey, P., (1975) Proc. R. Soc. London, Ser. A, 344, p. 111Baranauskas, V., Li, B.B., Peterlevitz, A., Tosin, M.C., Durrant, S.F., (1999) J. Appl. Phys., 85, p. 7455Baranauskas, V., Peled, A., Trava-Airoldi, V.J., Lima, C.A.S., Doi, I., Corat, E.J., (1994) Appl. Surf. Sci., 79-80, p. 129Barros, R.C.M., Corat, E.J., Ferreira, N.G., Souza, T.M., Trava-Airoldi, V.J., Leite, N.F., Iha, K., (1996) Diamond Relat. Mater., 5, p. 1323Lang, A.R., (1964) Proc. Phys. Soc., 84, p. 871Sumida, N., Lang, A.R., (1988) Proc. R. Soc. London, Ser. A, 419, p. 235Bridon, P.R., Jones, R., (1993) Physica B, 185, p. 17

The Hubbard model on a complete graph: Exact Analytical results

We derive the analytical expression of the ground state of the Hubbard model with unconstrained hopping at half filling and for arbitrary lattice sites.Comment: Email:[email protected]