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Peak Performance (peak + performance)
Selected AbstractsAPEX-Map: a parameterized scalable memory access probe for high-performance computing systems,CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 17 2007Erich Strohmaier Abstract The memory wall between the peak performance of microprocessors and their memory performance has become the prominent performance bottleneck for many scientific application codes. New benchmarks measuring data access speeds locally and globally in a variety of different ways are needed to explore the ever increasing diversity of architectures for high-performance computing. In this paper, we introduce a novel benchmark, APEX-Map, which focuses on global data movement and measures how fast global data can be fed into computational units. APEX-Map is a parameterized, synthetic performance probe and integrates concepts for temporal and spatial locality into its design. Our first parallel implementation in MPI and various results obtained with it are discussed in detail. By measuring the APEX-Map performance with parameter sweeps for a whole range of temporal and spatial localities performance surfaces can be generated. These surfaces are ideally suited to study the characteristics of the computational platforms and are useful for performance comparison. Results on a global-memory vector platform and distributed-memory superscalar platforms clearly reflect the design differences between these different architectures. Published in 2007 by John Wiley & Sons, Ltd. [source] Evaluating recursive filters on distributed memory parallel computersINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2006Przemys, aw Stpiczy, skiArticle first published online: 6 APR 200 Abstract The aim of this paper is to show that the recently developed high performance divide and conquer algorithm for solving linear recurrence systems with constant coefficients together with the new BLAS-based algorithm for narrow-banded triangular Toeplitz matrix,vector multiplication, allow to evaluate linear recursive filters efficiently on distributed memory parallel computers. We apply the BSP model of parallel computing to predict the behaviour of the algorithm and to find the optimal values of the method's parameters. The results of experiments performed on a cluster of twelve dual-processor Itanium 2 computers and Cray X1 are also presented and discussed. The algorithm allows to utilize up to 30% of the peak performance of 24 Itanium processors, while a simple scalar algorithm can only utilize about 4% of the peak performance of a single processor. Copyright © 2006 John Wiley & Sons, Ltd. [source] Combinatorial Electrochemical Synthesis and Screening of Mesoporous ZnO for PhotocatalysisMACROMOLECULAR RAPID COMMUNICATIONS, Issue 1 2004Thomas F. Jaramillo Abstract Summary: Automated electrochemical synthesis was used to create combinatorial libraries of mesoporous materials using tri-block copolymers as structure directing agents (SDA). An example library of 56 ZnO samples was synthesized, varying concentrations (0,15 wt.-%) of poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) , EO20PO70EO20. High-throughput photoelectrochemical screening for the measurement of water-splitting photocatalysis identified peak performance at 3 wt.-% of the SDA. Lamellar structures and disordered mesopores were observed by TEM and XRD. [source] Chinese response to allergy and asthma in Olympic athletesALLERGY, Issue 8 2008J. Li China is going to host the Games of the XXIX Olympiad from 8,24 August 2008 in Beijing. The number of athletes and accompanying individuals expected to arrive at China for the Beijing Olympics is estimated at over 10 000 and among them at least 2 000 (20%) are suspected to suffer from respiratory allergies. It is important to monitor the pollen counts and improve air quality in Beijing because Olympic athletes would be exposed to airborne allergens and pollutants during competitions which could hinder peak performance. The main pollen and spore families in Beijing are Artemisia, Ambrosia, Chenopodiaceae and Gramineae. They can reach around 307 000 grains of pollen/1000 m3 of air in August. Economic development in China is usually linked with worsening of air quality. Due to the adoption of various control measures, the ambient air quality in a number of areas in Beijing has actually improved. The ambient air TSP and SO2 levels in Beijing have been decreasing in the last decade. However, ambient air NOx level has been increasing due to the increased number of motor vehicles. Nevertheless, dedicated medical facilities in Beijing will provide medical services to athletes and delegations from all over the world during the Beijing Olympic Games. [source] Age-related changes in semen quality characteristics and expectations of reproductive longevity in Duroc boarsANIMAL SCIENCE JOURNAL, Issue 4 2010Yu Hung HUANG ABSTRACT Quadratic fitting was used to regress semen characteristics of 1441 samples consisting of 12-month collection from 58 Duroc boars against animal age varied from 10 to 80 months. Data was divided into two groups of cool (14.0,22.7°C, RH 81.5%) and hot season (22.9,29.9°C, RH 86.6%), to test effects of age, season and their interactions. Results revealed that young boars of around 1 year old could endure the hot season. The endurance gradually diminished as animals grew. In the hot season animals exhibited peak performance at age around 33 month and it remained for 1 month, while cool-season kept boars could last for 48 months from 16 months old onward. The reproductive longevity should be 51 month in a subtropical environment and it may extend to 70 month if heat stress can be avoided. The estimated total sperm contribution of a Duroc boar would be 1.8 times more when kept below 22°C than in a natural subtropical environment. It is concluded that to maintain Duroc boars as semen donor to at least 4 years of age is feasible in a subtropical environment and boar longevity could reach 6 years old if well kept in a temperate region. [source] Direct utilization of ethanol on ceria-based anodes for solid oxide fuel cellsASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 1 2009Massimiliano Cimenti Abstract The direct utilization of ethanol was investigated in CuCeO2, CuZr0.35Ce0.65O2 (ZDC) and Cu/RuZr0.35Ce0.65O2 anodes for solid oxide fuel cells (SOFC). The anodes were prepared by impregnation with nitrate precursors on a porous layer of yttria-stabilized zirconia (YSZ) obtained by tape casting, while (La0.8Sr0.2MnO3,,) LSM cathodes were screen-printed. The cells were tested in both hydrogen and ethanol. The outlet gas composition was monitored with a gas chromatograph, which showed that almost all the ethanol was decomposed, mainly to H2, CH4, CO, H2O and C2H4. The maximum power outputs obtained in ethanol were 0.075 and 0.400 W/cm2 on CuCeO2|YSZ|LSM and CuZDC|YSZ|LSM, respectively. All cells were more active in alcohol than in hydrogen with the peak performance occurring after approximately 4 h. That is, the power density initially increased, peaked and then decreased. This behavior was likely a consequence of carbon deposition that initially results in an improvement of the electronic conductivity in the anode but later results in the blocking of the active sites. Zirconia doping (in the ZDC anodes) resulted in better stability and, in addition, the initial activity of the ZDC anodes could be recovered after approximately 1 h of exposure to humidified hydrogen, whereas the initial activity of the ceria anodes could not be recovered. The addition of ruthenium (<0.5 wt%) further improved the stability by delaying the onset of carbon formation. Copyright © 2008 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Surface Modification by Compositionally Modulated Multilayered Zn-Fe Alloy CoatingsCHINESE JOURNAL OF CHEMISTRY, Issue 12 2008V. THANGARAJ Abstract Compositionally modulated multilayered alloy (CMMA) coatings of Zn-Fe were developed from acid chloride baths by single bath technique. The production and properties of CMMA Zn-Fe coatings were tailored as a function of switching cathode current densities (SCCD's) and thickness of individual layers. Corrosion rates (CR) were measured by electrochemical methods. Corrosion resistances were found to vary with SCCD's and the number of sub layers in the deposit. SCCD's were optimized for production of Zn-Fe CMMA electroplates showing peak performance against corrosion. The formation of discrete Zn-Fe alloy layers having different compositions in the deposits were demonstrated by scanning electron microscopy (SEM). Improvements in the corrosion resistance of multilayered alloys are due to the inherent barrier properties of CMMA coatings as evidenced by electrochemical impedance spectroscopy (EIS). Corrosion resistance afforded by Zn-Fe CMMA coatings are explained in terms of the n-type semiconductor films at the interface, supported by Mott-Schottky's plot. It was observed that the alloy with high w(Fe) on the top showed better corrosion resistance compared to that with the less w(Fe) on top. At optimum SCCD's of 3.0,5.5 A·dm,2, a Zn-Fe CMMA coatings with 600 sub layers showed ca. 45 times better corrosion resistance than conventional Zn-Fe alloy of the same thickness. The deposit showed no red rust even up to 1130 h in salt spray test. [source] | ||||||||||