4,078 research outputs found
GraphBLAST: A High-Performance Linear Algebra-based Graph Framework on the GPU
High-performance implementations of graph algorithms are challenging to
implement on new parallel hardware such as GPUs because of three challenges:
(1) the difficulty of coming up with graph building blocks, (2) load imbalance
on parallel hardware, and (3) graph problems having low arithmetic intensity.
To address some of these challenges, GraphBLAS is an innovative, on-going
effort by the graph analytics community to propose building blocks based on
sparse linear algebra, which will allow graph algorithms to be expressed in a
performant, succinct, composable and portable manner. In this paper, we examine
the performance challenges of a linear-algebra-based approach to building graph
frameworks and describe new design principles for overcoming these bottlenecks.
Among the new design principles is exploiting input sparsity, which allows
users to write graph algorithms without specifying push and pull direction.
Exploiting output sparsity allows users to tell the backend which values of the
output in a single vectorized computation they do not want computed.
Load-balancing is an important feature for balancing work amongst parallel
workers. We describe the important load-balancing features for handling graphs
with different characteristics. The design principles described in this paper
have been implemented in "GraphBLAST", the first high-performance linear
algebra-based graph framework on NVIDIA GPUs that is open-source. The results
show that on a single GPU, GraphBLAST has on average at least an order of
magnitude speedup over previous GraphBLAS implementations SuiteSparse and GBTL,
comparable performance to the fastest GPU hardwired primitives and
shared-memory graph frameworks Ligra and Gunrock, and better performance than
any other GPU graph framework, while offering a simpler and more concise
programming model.Comment: 50 pages, 14 figures, 14 table
Determination of trophic situation of Sarimsakli Dam Lake (Kayseri-Turkey)
In this study, water samples were collected from four different stations in Sar.msakl. Dam Lake from May 2001 to June 2002 monthly to determine the trophic situation of lake. Additionally, physical parameters of water such as temperature, dissolved oxygen, electrical conductivity (EC), pH, light permeability were measured in the field and status of surface active substance, sulphur, nitrite, nitrate, total nitrogen, phosphate, total phosphate, oxygen saturation were analysed in Environment MinistryReference Laboratory. Zooplankton samples were collected with a plankton net mesh size of 55 ƒÊm horizontally and vertically and they were fixed with 4% formaldehyde. The results of the light permeability, basic water quality parameters and dominant zooplankton species indicated that the lake studied was eutrophic. Furthermore, biotic index confirmed this result. The Lake examined in study area was partly polluted with different sources, because the study area is liable to human activities. If the pollution is not prevented, it may endanger the lives of living organisms here in future. Knowledge on the trophic situation of Sar.msakl. Dam Lake is not well established; so all of the zooplankton species determined are new records
A comparison of the Bering Sea, Gulf of Alaska, and Aleutian Islands large marine ecosystems through food web modeling / by K. Aydin ... [et al.]
Detailed mass balance food web models were constructed to compare ecosystem characteristics for three Alaska regions: the eastern Bering Sea (EBS), the Gulf of Alaska (GOA), and the Aleutian Islands (AI). This paper documents the methods and data used to construct the models and compares ecosystem structure and indicators across models. The common modeling framework, including biomass pool and fishery definitions, resulted in comparable food webs for the three ecosystems which showed that they all have the same apex predator—the Pacific halibut longline fishery. However, despite the similar methods used to construct the models, the data from each system included in the analysis clearly define differences in food web structure which may be important considerations for fishery management in Alaska ecosystems. The results showed that the EBS ecosystem has a much larger benthic influence in its food web than either the GOA or the AI. Conversely, the AI ecosystem has the strongest pelagic influence in its food web relative to the other two systems. The GOA ecosystem appears balanced between benthic and pelagic pathways, but is notable in having a smaller fisheries catch relative to the other two systems, and a high biomass of fish predators above trophic level (TL) 4, arrowtooth flounder and halibut. The patterns visible in aggregated food webs were confirmed in additional more detailed analyses of biomass and consumption in each ecosystem, using both the single species and whole ecosystem indicators developed here
A new approach to dynamic finite-size scaling
In this work we have considered the Taylor series expansion of the dynamic
scaling relation of the magnetization with respect to small initial
magnetization values in order to study the dynamic scaling behaviour of 2- and
3-dimensional Ising models. We have used the literature values of the critical
exponents and of the new dynamic exponent to observe the dynamic
finite-size scaling behaviour of the time evolution of the magnetization during
early stages of the Monte Carlo simulation. For 3-dimensional Ising Model we
have also presented that this method opens the possibility of calculating
and separately. Our results show good agreement with the literature
values. Measurements done on lattices with different sizes seem to give very
good scaling.Comment: Latex file with six figures. Accepted for publication in IJM
Nearly Four Million California Adults Are Victims of Intimate Partner Violence
Based on 2007 California Health Interview Survey data, analyzes the incidence and nature of physical and/or sexual intimate partner violence by gender, race/ethnicity, nativity, marital status, and sexual orientation
The effect of long-term feeding of conjugated linoleic acid on fertility in Japanese quail
The objective of this study was to determine the effects of the long-term feeding of conjugated linoleic acid (CLA) on laying hen performance, egg fertility and hatchability of fertile eggs of Japanese quail (Coturnix coturnix japonica). One hundred and sixty 7-day old Japanese quail chicks were randomly assigned to four groups (40 birds per group) and fed for five weeks on a commercial diet supplemented with either 0.5% hazelnut (Group A), 0.5% sunflower oil (Group B), 0.25% CLA (Group C) or 0.5% CLA (Group D). The birds received water and feed ad libitum during the study. At the end of the five weeks the birds were sexed, and 21 females and seven males from each group were selected. For a further six weeks these selected birds were fed a layer diet supplemented with their respective sources of oil. Eggs were collected daily and incubated weekly. The fertility rate was determined by visual inspection at the end of the incubation period. Dietary CLA at the inclusion level of 0.5%, but not at 0.25%, caused a significant decrease in percentage hatchability of the fertile eggs compared to Groups A and B. Hatchability of fertile eggs from Groups A, B, C and D was 74, 80, 72 and 70, respectively. Fertility rates between Groups A, B, C and D did not differ significantly, and were 64.4, 56.4, 66.0 and 62.8%, respectively. Hen-day egg production of Groups A, C and D were similar, but in weeks 3, 4, 5 and 6, hens in Group B had a significantly lower hen-day egg production (%) compared to Group A. Also, in weeks 3, 4, 5 and 6, egg size in Group B was significantly lower than that in the other groups. From this study it is concluded that dietary CLA at inclusion levels of 0.25% or 0.5% did not influence egg fertility, egg weight and egg production in Japanese quail. South African Journal of Animal Science Vol. 36(2) 2006: 99-10
NMPC using Pontryagin’s Minimum Principle-Application to a two-phase semi-batch hydroformylation reactor under uncertainty
Failure of the Standard Coupled-Channels Method in Describing the Inelastic Reaction Data: On the Use of a New Shape for the Coupling Potential
We present the failure of the standard coupled-channels method in explaining
the inelastic scattering together with other observables such as elastic
scattering, excitation function and fusion data. We use both microscopic
double-folding and phenomenological deep potentials with shallow imaginary
components. We argue that the solution of the problems for the inelastic
scattering data is not related to the central nuclear potential, but to the
coupling potential between excited states. We present that these problems can
be addressed in a systematic way by using a different shape for the coupling
potential instead of the usual one based on Taylor expansion.Comment: 10 pages, 4 figures, 1 table, Latex:RevTex4 published in J. Phys. G:
Nucl. Part. Phy
The Strong Decay Patterns of the Exotic Hybrid Mesons
We calculate the coupling constants of the decay modes
within the framework of the light-cone QCD sum rule. Then we calculate the
partial width of these decay channels, which differ greatly from the existing
calculations using phenomenological models. For the isovector state,
the dominant decay modes are . For its isoscalar partner, its
dominant decay mode is . We also discuss the possible search of the
state at BESIII, for example through the decay chains or where can
be reconstructed through the decay modes
or . Hopefully the present work will be helpful to the
experimental establishment of the hybrid meson.Comment: 14 pages, 10 figure
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