Line-by-line spectroscopic simulations on graphics processing units

We report here on software that performs line-by-line spectroscopic simulations on gases. Elaborate models (such as narrow band and correlated-K) are accurate and efficient for bands where various components are not simultaneously and significantly active. Line-by-line is probably the most accurate model in the infrared for blends of gases that contain high proportions of H₂O and CO₂ as this was the case for our prototype simulation. Our implementation on graphics processing units sustains a speedup close to 330 on computation-intensive tasks and 12 on memory intensive tasks compared to implementations on one core of high-end processors. This speedup is due to data parallelism, efficient memory access for specific patterns and some dedicated hardware operators only available in graphics processing units. It is obtained leaving most of processor resources available and it would scale linearly with the number of graphics processing units in parallel machines. Line-by-line simulation coupled with simulation of fluid dynamics was long believed to be economically intractable but our work shows that it could be done with some affordable additional resources compared to what is necessary to perform simulations on fluid dynamics alone.<h4 id="absSec_N1af24720N1e664e40">Program summaryh4>Program title: GPU4RECatalogue identifier: ADZY_v1_0Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADZY_v1_0.htmlProgram obtainable from: CPC Program Library, Queen's University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 62&thinsp;776No. of bytes in distributed program, including test data, etc.: 1&thinsp;513&thinsp;247Distribution format: tar.gzProgramming language: C++Computer: x86 PCOperating system: Linux, Microsoft Windows. Compilation requires either gcc/g++ under Linux or Visual C++ 2003/2005 and Cygwin under Windows. It has been tested using gcc 4.1.2 under Ubuntu Linux 7.04 and using Visual C++ 2005 with Cygwin 1.5.24 under Windows XP.RAM: 1 gigabyteClassification: 21.2External routines: OpenGL (http://www.opengl.org)Nature of problem: Simulating radiative transfer on high-temperature high-pressure gases.Solution method: Line-by-line Monte-Carlo ray-tracing.Unusual features: Parallel computations are moved to the GPU.Additional comments: nVidia GeForce 7000 or ATI Radeon X1000 series graphics processing unit is required.Running time: A few minutes.     

GM(n,h)模型建模序列数据数乘变换特性研究

基于数乘变换是灰色系统建模过程中数据处理的基础,讨论了ＧＭ（n,h）模型与其他几类灰色模型的内在联系．将各类灰色模型统一于共同的分析体系,并在此基础上研究了数乘变换对ＧＭ（n,h）模型参数取值的影响．指出了模型的模拟和预测值只与因变量的数乘变换有关,而与自变量的变换无关．最后分析了几个特殊灰色模型的数乘变换性质,该结果对研究系列灰色模型参数特征有重要意义．     

In-line holographic electron microscopy in the presence of external magnetic fields

It is now a well-known fact that the phase of electron waves is altered by external magnetic fields via the Aharonov-Bohm effect. This implies that any electron interference effects will be to some degree affected by the presence of such fields. In this study we examine the distortion effects of external (constant and variable) magnetic fields on electron interference and holography. For digital holography, the reconstruction of the object is done via numerical calculations and this leaves the door open for correcting phase distortions in the hologram reconstruction. We design and quantitatively assess such correction schemes, which decidedly depend on our knowledge of the magnetic field values in the holographic recording process. For constant fields of known value we are able to correct for magnetic distortions to a great extent. We find that variable fields are more destructive to the holographic process than constant fields. We define two criteria, related respectively to global and local contrast of the hologram to establish the maximum allowed external field which does not significantly hinder the accuracy of in-line holographic microscopy with electrons.     

A mathematical programming approach to a problem in variance penalised Markov decision processes

In this paper we present three algorithms for solving a problem in which it is required to get an optimal compromise between the average expected reward per unit time and the variance of the reward per unit time. The algorithms lead to anh6p326q56221tx02/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">-optimal solution, whereh6p326q56221tx02/xxlarge603.gif" alt="epsiv" align="BASELINE" BORDER="0">>0 is arbitrary.     

Analytical techniques in high temperature corrosion

This paper considers the application of analytical techniques (particularly AES, SIMS, RHEED, laser Raman, Mössbauer, TEM, EELS) to high-temperature oxidation studies. Specific systems reviewed include NiO on Ni, oxides on Fe, Cr and their alloys, and Al₂O₃ on Al and h3083/xxlarge946.gif" alt="beta" align="MIDDLE" BORDER="0">-NiAl. The often complementary information provided by the various techniques leads to a better understanding of oxide growth mechanisms on an atomic sale, interfacial segregation phenomena, and the role of reactive elements in modifying transport processes in oxides.     

Production of perovskite-like La1−xCaxMnO3+δ ferromagnetic thin films by electrochemical reduction

Ferromagnetic and perovskite-like thin films (<1h62026068581x8/xxlarge956.gif" alt="mgr" align="MIDDLE" BORDER="0">m) of La1–xCaxMnO3+h62026068581x8/xxlarge948.gif" alt="delta" align="BASELINE" BORDER="0"> have been routinely prepared by heat treatment of an amorphous La–Ca–Mn precursor. The precursor was electrodeposited cathodically in the absence of oxygen and water onto polished silver substrates from a nonaqueous solution of the components' nitrates. Analysis by X-ray diffraction and SQUID magnetometry shows these materials exhibit the appropriate structural and magnetic phases indicative of colossal magnetoresistance.     

Isochoric p-ρ-T Measurements on 1,1-Difluoroethane (R152a) from 158 to 400 K and 1,1,1-Trifluoroethane (R143a) from 166 to 400 K at Pressures to 35 MPa

The p-h51h437771l84g21/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">-T relationships have been measured for 1,1-difluoroethane (R152a) and 1,1,1-trifluoroethane (R143a) by an isochoric method with gravimetric determinations of the amount of substance. Temperatures ranged from 158 to 400 K for R152a and from 166 to 400 K for R143a, while pressures were up to 35 MPa. Measurements were conducted on compressed liquid samples. Determinations of saturated liquid densities were made by extrapolating each isochore to the vapor pressure, and determining the temperature and density at the intersection. Published p-h51h437771l84g21/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">-T data are in good agreement with this study. For the p-h51h437771l84g21/xxlarge961.gif" alt="rgr" align="MIDDLE" BORDER="0">-T apparatus, the uncertainty of the temperature is ±0.03 K, and for pressure it is ±0.01% at p>3 MPa and ±0.05% at p&#60;3 MPa. The principal source of uncertainty is the cell volume (h51h437771l84g21/xxlarge8764.gif" alt="sim" align="MIDDLE" BORDER="0">28.5 cm³), which has a standard uncertainty of ±0.003 cm³. When all components of experimental uncertainty are considered, the expanded relative uncertainty (with a coverage factor k=2 and thus a two-standard deviation estimate) of the density measurements is estimated to be ±0.05%.     

On a quasiorder on the class of monounary algebras

In the paper we introduce a relation h3/MediaObjects/s00500-005-0520-xflb1.gif" alt="MediaObjects/s00500-005-0520-xflb1.gif" align="middle"> on the class of monounary algebras h3/MediaObjects/s00500-005-0520-xflb2.gif" alt="MediaObjects/s00500-005-0520-xflb2.gif" align="middle"> by means of h3/MediaObjects/s00500-005-0520-xflb3.gif" alt="MediaObjects/s00500-005-0520-xflb3.gif" align="middle">-homomorphisms. It is a quasiorder. We take a subclass h3/MediaObjects/s00500-005-0520-xflb4.gif" alt="MediaObjects/s00500-005-0520-xflb4.gif" align="middle"> of h3/MediaObjects/s00500-005-0520-xflb2.gif" alt="MediaObjects/s00500-005-0520-xflb2.gif" align="middle"> containing monounary algebras h3/MediaObjects/s00500-005-0520-xflb5.gif" alt="MediaObjects/s00500-005-0520-xflb5.gif" align="middle"> satisfying the property h3/MediaObjects/s00500-005-0520-xflb6.gif" alt="MediaObjects/s00500-005-0520-xflb6.gif" align="middle"> We characterize algebras in h3/MediaObjects/s00500-005-0520-xflb4.gif" alt="MediaObjects/s00500-005-0520-xflb4.gif" align="middle"> by the notions of a degree and properties of their h3/MediaObjects/s00500-005-0520-xflb3.gif" alt="MediaObjects/s00500-005-0520-xflb3.gif" align="middle">-endomorphisms. We apply the results to finite monounary algebras. Supported by grant VEGA 1/0161/03