633 research outputs found
Modula-2*: An extension of Modula-2 for highly parallel programs
Parallel programs should be machine-independent, i.e., independent of properties that are likely to differ from one parallel computer to the next. Extensions are described of Modula-2 for writing highly parallel, portable programs meeting these requirements. The extensions are: synchronous and asynchronous forms of forall statement; and control of the allocation of data to processors. Sample programs written with the extensions demonstrate the clarity of parallel programs when machine-dependent details are omitted. The principles of efficiently implementing the extensions on SIMD, MIMD, and MSIMD machines are discussed. The extensions are small enough to be integrated easily into other imperative languages
Intensificação da coloração da epiderme de pêssegos cv. Eldorado, em função do uso de cobertura plástica no solo.
bitstream/item/31610/1/comunicado83.pd
Alterações morfo-fisiologicas em tecidos de pessegueiro e relação com a morte precoce de plantas.
bitstream/CPACT/570/1/boletim_56.pd
Umidade ponderal em tecidos de pereira durante o período de dormência sob condições de inverno ameno.
O objetivo deste trabalho foi avaliar a umidade ponderal (UP) em diferentes tecidos das cultivares de pereira Kieffer (Pyrus communis) e Housui (Pyrus pyrifolia), durante a dormência, em condições de inverno ameno. Foram avaliadas plantas do pomar experimental da Embrapa Clima Temperado, Pelotas, RS. Utilizouse o delineamento experimental inteiramente casualizado, em esquema fatorial 3x4x5, que consistiu em três tecidos (gema, casca e lenho), quatro porções de ramos (terminal, mediana, axial e esporões) e cinco datas de coleta, em 2005 (1/7, 3/8, 6/9, 23/9 e 13/10), com parcelas subdivididas e três repetições. Houve aumento na UP do lenho na cultivar Kieffer até a metade da dormência, com subsequente redução a partir desta fase, o que pode ser atribuído ao aumento na UP observado nas gemas após satisfação da exigência em frio e superação de dormência. Na cultivar Housui, a insatisfação da exigência em frio, associada à ocorrência de altas temperaturas durante o inverno, refletiu-se na redução da UP e na desidratação das gemas durante a dormência. A dinâmica da água em tecidos de pereira é diretamente influenciada pelo acúmulo de frio hibernal e depende da exigência em frio de cada cultivar
Post processing of additively manufactured metal parts by using pulse electrochemical machining
In response of the growing demand for higher product requirements concerning quality, durability and efficiency by simultaneously decreasing product life cycles, the product development has to consider suitable production technologies at an early stage of the development process. This implicates also the choice of new manufacturing or technology approaches. Additively manufactured parts can be produced with a high geometrical complexity. To produce such geometrically complex parts from metal, the so called selective laser melting (SLM) technology is often the method of choice. In order to produce SLM-parts, support structures have to be used. They have several functions, such as connecting the component to a building platform, supporting overhanging and tilted areas but they also dissipate the heat of fusion. However, those support structures have to be removed for the use of the component, which often involves numerous time- consuming and difficult to automatize operation steps. A promising alternative can be pulse electrochemical machining (PECM) as there is no contact between tool and workpiece. This allows the adaption of the tool to complex geometries and the improvement of the workpiece surface quality in one machining step. Therefore, a fundamental study of the electrochemical dissolution behavior and machinability aspects of the support structures is performed
Latency hiding in parallel systems: a quantitative approach
In many parallel applications, network latency causes a dramatic
loss in processor utilization. This paper examines software
pipelining as a technique for network latency hiding. It
quantifies the potential improvements with
detailed,instruction-level simulations.
The benchmarks used are the Livermore Loop kernels and BLAS Level
1.
These were parallelized and run on the instruction-level RISC
simulator DLX, extended with both a blocking and a pipelined
network. Our results show that prefetch in a pipelined network
improves performance by a factor of 2 to 9, provided the network
has sufficient bandwidth to accept at least 10 requests per
processor
Efficient parallel computation on workstation clusters
We present novel hard- and software that efficiently implements
communication primitives for parallel execution on Workstation
clusters. We provide low communication latencies, minimal protocol,
zero operating system overhead, and high throughput. With this
technology, it is possible to build effective parallel systems
using off-the-shelf workstations. Our goal is to develop a standard
interfaceboard and the necessary software for interfacing any
number of computers, from a workstation to a cabinet full of
workstation-boards
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