997 resultados para computational architecture
Resumo:
Upper Devonian to Lower Carboniferous strata of the Campwyn Volcanics of east central Queensland preserve a substantial sequence of first-cycle volcaniclastic sedimentary and coeval volcanic rocks that record prolonged volcanic activity along the northern New England Fold Belt. The style and scale of volcanism varied with time, producing an Upper Devonian sequence of mafic volcano-sedimentary rocks overlain by a rhyolitic ignimbrite-dominated sequence that passes upward into a Lower Carboniferous limestone-bearing sedimentary sequence. We define two facies associations for the Campwyn Volcanics. A lower facies association is dominated by mafic volcanic-derived sedimentary breccias with subordinate primary mafic volcanic rocks comprising predominantly hyaloclastite and peperite. Sedimentary breccias record episodic and high energy, subaqueous depositional events with clastic material sourced from a mafic lava-dominated terrain. Some breccias contain a high proportion of attenuated dense, glassy mafic juvenile clasts, suggesting a syn-eruptive origin. The lower facies association coarsens upwards from a lithic sand-dominated sequence through a thick interval of pebble- to boulder-grade polymict volcaniclastic breccias, culminating in facies that demonstrate subaerial exposure. The silicic upper facies association marks a significant change in eruptive style, magma composition and the nature of eruptive sources, as well as the widespread development of subaerial depositional conditions. Crystal-rich, high-grade, low- to high-silica rhyolite ignimbrites dominate the base of this facies association. Biostratigraphic age controls indicate that the ignimbrite-bearing sequences are Famennian to lower-mid Tournaisian in age. The ignimbrites represent extra-caldera facies with individual units up to 40 m thick and mostly lacking coarse lithic breccias. Thick deposits of pyroclastic material interbedded with fine-grained siliceous sandstone and mudstone (locally radiolarian-bearing) were deposited from pyroclastic flows that crossed palaeoshorelines or represent syn-eruptive, resedimented pyroclastic material. Some block-bearing lithic-pumice-crystal breccias may also reflect more proximal subaqueous silicic explosive eruptions. Crystal-lithic sandstones interbedded with, and overlying the ignimbrites, contain abundant detrital volcanic quartz and feldspar derived from the pyroclastic deposits. Limestone is common in the upper part of the upper facies association, and several beds are oolitic (cf. Rockhampton Group of the Yarrol terrane). Overall, the upper facies association fines upward and is transgressive, recording a return to shallow-marine conditions. Palaeocurrent data from all stratigraphic levels in the Campwyn Volcanics indicate that the regional sediment-dispersal direction was to the northwest, and opposed to the generally accepted notion of easterly sediment dispersal from a volcanic arc source. The silicic upper facies association correlates in age and lithology to Early Carboniferous silicic volcanism in the Drummond (Cycle 1) and Burdekin Basins, Connors Arch, and in the Yarrol terranes of eastern Queensland. The widespread development of silicic volcanism in the Early Carboniferous indicates that silicic (rift-related) magmatism was not restricted to the Drummond Basin, but was part of a more substantial silicic igneous province.
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Signal peptides and transmembrane helices both contain a stretch of hydrophobic amino acids. This common feature makes it difficult for signal peptide and transmembrane helix predictors to correctly assign identity to stretches of hydrophobic residues near the N-terminal methionine of a protein sequence. The inability to reliably distinguish between N-terminal transmembrane helix and signal peptide is an error with serious consequences for the prediction of protein secretory status or transmembrane topology. In this study, we report a new method for differentiating protein N-terminal signal peptides and transmembrane helices. Based on the sequence features extracted from hydrophobic regions (amino acid frequency, hydrophobicity, and the start position), we set up discriminant functions and examined them on non-redundant datasets with jackknife tests. This method can incorporate other signal peptide prediction methods and achieve higher prediction accuracy. For Gram-negative bacterial proteins, 95.7% of N-terminal signal peptides and transmembrane helices can be correctly predicted (coefficient 0.90). Given a sensitivity of 90%, transmembrane helices can be identified from signal peptides with a precision of 99% (coefficient 0.92). For eukaryotic proteins, 94.2% of N-terminal signal peptides and transmembrane helices can be correctly predicted with coefficient 0.83. Given a sensitivity of 90%, transmembrane helices can be identified from signal peptides with a precision of 87% (coefficient 0.85). The method can be used to complement current transmembrane protein prediction and signal peptide prediction methods to improve their prediction accuracies. (C) 2003 Elsevier Inc. All rights reserved.
Resumo:
In this paper we examine the effects of varying several experimental parameters in the Kane quantum computer architecture: A-gate voltage, the qubit depth below the silicon oxide barrier, and the back gate depth to explore how these variables affect the electron density of the donor electron. In particular, we calculate the resonance frequency of the donor nuclei as a function of these parameters. To do this we calculated the donor electron wave function variationally using an effective-mass Hamiltonian approach, using a basis of deformed hydrogenic orbitals. This approach was then extended to include the electric-field Hamiltonian and the silicon host geometry. We found that the phosphorous donor electron wave function was very sensitive to all the experimental variables studied in our work, and thus to optimize the operation of these devices it is necessary to control all parameters varied in this paper.
Resumo:
Functional knowledge of the physiological basis of crop adaptation to stress is a prerequisite for exploiting specific adaptation to stress environments in breeding programs. This paper presents an analysis of yield components for pearl millet, to explain the specific adaptation of local landraces to stress environments in Rajasthan, India. Six genotypes, ranging from high-tillering traditional landraces to low-tillering open-pollinated modern cultivars, were grown in 20 experiments, covering a range of nonstress and drought stress patterns. In each experiment, yield components (particle number, grain number, 100 grain mass) were measured separately for main shoots, basal tillers, and nodal tillers. Under optimum conditions, landraces had a significantly lower grain yield than the cultivars, but no significant differences were observed at yield levels around 1 ton ha(-1). This genotype x environment interaction for grain yield was due to a difference in yield strategy, where landraces aimed at minimising the risk of a crop failure under stress conditions, and modem cultivars aimed at maximising yield potential under optimum conditions. A key aspect of the adaptation of landraces was the small size of the main shoot panicle, as it minimised (1) the loss of productive tillers during stem elongation; (2) the delay in anthesis if mid-season drought occurs; and (3) the reduction in panicle productivity of the basal tillers under stress. In addition, a low investment in structural panicle weight, relative to vegetative crop growth rate, promoted the production of nodal tillers, providing a mechanism to compensate for reduced basal tiller productivity if stress occurred around anthesis. A low maximum 100 grain mass also ensured individual grain mass was little affected by environmental conditions. The strategy of the high-tillering landraces carries a yield penalty under optimum conditions, but is expected to minimise the risk of a crop failure, particularly if mid-season drought stress occurs. The yield architecture of low-tillering varieties, by contrast, will be suited to end-of-season drought stress, provided anthesis is early. Application of the above adaptation mechanisms into a breeding program could enable the identification of plant types that match the prevalent stress patterns in the target environments. (C) 2003 E.J. van Oosterom. Published by Elsevier Science B.V. All rights reserved.
Resumo:
Arquitetura Corporativa promove o estabelecimento de uma visão holística da estrutura e forma de trabalho de uma organização. Um dos aspectos abordados em Arquitetura Corporativa está associada a "estrutura ativa" da organização, que diz respeito a “quem" realiza as atividades organizacionais. Várias abordagens têm sido propostas a fim de proporcionar um meio para a representação de Arquitetura Corporativa, entre as quais ARIS, RM-ODP, UPDM e ArchiMate. Apesar da aceitação por parte da comunidade, as abordagens existentes se concentram em propósitos diferentes, têm limitações de escopo e algumas não têm semântica de mundo real bem definida. Além das abordagens de modelagem, muitas abordagens de ontologias têm sido propostas, a fim de descrever o domínio de estrutura ativa, incluindo as ontologias de SUPER Project, TOVE, Enterprise Ontology e W3C Org Ontology. Embora especificadas para fundamentação semântica e negociação de significado, algumas das abordagens propostas têm fins específicos e cobertura limitada. Além disso, algumas das abordagens não são definidas usando linguagens formais e outras são especificadas usando linguagens sem semântica bem definida. Este trabalho apresenta uma ontologia de referência bem fundamentada para o domínio organizacional. A ontologia organizacional de referência apresentada abrange os aspectos básicos discutidos na literatura organizacional, tais como divisão do trabalho, relações sociais e classificação das unidades estruturais. Além disso, também abrange os aspectos organizacionais definidos em abordagens existentes, levando em consideração tanto abordagens de modelagem quanto abordagens ontológicas. A ontologia resultante é especificada em OntoUML e estende os conceitos sociais de UFO-C.
Resumo:
Mapas Conceituais são representações gráficas do conhecimento de uma pessoa num dado momento e área de conhecimento. Por sua natureza investigativa, são utilizados como ferramentas de apoio em abordagens pedagógicas que objetivam promover a aprendizagem significativa. No entanto, o processo de avaliação de um mapa tende a ser custoso pois acarreta uma pesada carga de processamento cognitivo por parte do avaliador, já que este precisa mapear os conceitos e relações em busca de nuances de conhecimento alí presentes. Essa pesquisa tem por objetivo aumentar o nível de abstração nas interações entre o avaliador e os mapas conceituais fornecendo uma camada intermediária de inteligência computacional que favoreça a comunicação por meio de perguntas e respostas em linguagem natural, fornecendo ao avaliador ferramentas que lhe permita examinar o conteúdo do mapa conceitual sem exigir deste o mapeamento visual dos conceitos e relações presentes nos mapas avaliados. Uma ferramenta é prototipada e uma prova de conceito apresentada. A análise da arquitetura proposta permitiu definir uma arquitetura final com características que permitem potencializar o uso de mapas conceituais e facilitar diversas operações pedagógicas com estes. Essa pesquisa situa-se na área de investigação de sistemas de perguntas e resposta, aplicando técnicas de processamento de linguagem natural para análise da pergunta e interpretação do mapa conceitual e aplica técnica de inteligência artificial para inferir respostas às perguntas.
Resumo:
ABSTRACT The objective of this study was to analyze the phenotypic correlation and path analysis of traits related to plant architecture, earliness and grain yield in F2, BC1 and BC2 generations, from crosses between cowpea cultivars BRS Carijó and BR14 Mulato. Most phenotypic correlations of the examined traits were concordant in statistical significance, with approximate values among the examined generations. For the trait seed weight, significant and positive phenotypic correlations were observed in the three generations only for the trait number of secondary branches. The values of the direct effects were in agreement with the values of the phenotypic correlations, which indicate true association by the phenotypic correlation among the traits of grain yield examined. Path analysis indicated that the selection of productive plants will result in early plants and an increased number of secondary branches. In F2, plants with shorter length of the main branch and shorter length of secondary branches can be obtained. The causal model explained 15 to 30% of the total variation in grain weight in relation to the traits examined. The analyses indicated the possibility of selecting plants with a higher and early grain yield, shorter length of primary branches and lower number of nodes, which are important variables for mechanical or semi-mechanical harvesting.
Resumo:
Joining efforts of academic and corporate teams, we developed an integration architecture - MULTIS - that enables corporate e-learning managers to use a Learning Management System (LMS) for management of educational activities in virtual worlds. This architecture was then implemented for the Formare LMS. In this paper we present this architecture and concretizations of its implementation for the Second Life Grid/OpenSimulator virtual world platforms. Current systems are focused on activities managed by individual trainers, rather than groups of trainers and large numbers of trainees: they focus on providing the LMS with information about educational activities taking place in a virtual world and/or being able to access within the virtual world some of the information stored in the LMS, and disregard the streamlining of activity setup and data collection in multi-trainer contexts, among other administrative issues. This architecture aims to overcome the limitations of existing systems for organizational management of corporate e-learning activities.
Resumo:
O trabalho apresentado por este documento aborda os problemas que advêm da necessidade de integração de aplicações, desenvolvidas em diferentes instantes no tempo, por diferentes equipas de trabalho, que para enriquecer os processos de negócio necessitam de comunicar entre si. A integração das aplicações tem de ser feita de forma opaca para estas, sendo disponibilizada por uma peça de software genérica, robusta e sem custos para as equipas desenvolvimento, na altura da integração. Esta integração tem de permitir que as aplicações comuniquem utilizando os protocolos que desejarem. Este trabalho propõe um middleware orientado a mensagens como solução para o problema identificado. A solução apresentada por este trabalho disponibiliza a comunicação entre aplicações que utilizam diferentes protocolos, permite ainda o desacoplamento temporal, espacial e de sincronismo na comunicação das aplicações. A implementação da solução tem base num sistema publish/subscribe orientado ao conteúdo e tem de lidar com as maiores exigências computacionais que este tipo de sistema acarta, sendo que a utilização deste se justifica com o enriquecimento da semântica de subscrição de eventos. Esta implementação utiliza uma arquitectura semi-distribuída, com o objectivo de aumentar a escalabilidade do sistema. A utilização da arquitectura semi-distribuída implica que a implementação da solução tem de lidar com o encaminhamento de eventos e divulgação das subscrições, pelos vários servidores de eventos. A implementação da solução disponibiliza garantias de persistência, processamento transaccional e tolerância a falhas, assim como transformação de eventos entre os diversos protocolos. A extensibilidade da solução é conseguida à custa de um sistema de pluggins que permite a adição de suporte a novos protocolos de comunicação. Os protocolos suportados pela implementação final do trabalho são RestMS e TCP.
Computational evaluation of hydraulic system behaviour with entrapped air under rapid pressurization
Resumo:
The pressurization of hydraulic systems containing entrapped air is considered a critical condition for the infrastructure's security due to transient pressure variations often occurred. The objective of the present study is the computational evaluation of trends observed in variation of maximum surge pressure resulting from rapid pressurizations. The comparison of the results with those obtained in previous studies is also undertaken. A brief state of art in this domain is presented. This research work is applied to an experimental system having entrapped air in the top of a vertical pipe section. The evaluation is developed through the elastic model based on the method of characteristics, considering a moving liquid boundary, with the results being compared with those achieved with the rigid liquid column model.
Resumo:
In this review paper different designs based on stacked p-i'-n-p-i-n heterojunctions are presented and compared with the single p-i-n sensing structures. The imagers utilise self-field induced depletion layers for light detection and a modulated laser beam for sequential readout. The effect of the sensing element structure, cell configurations (single or tandem), and light source properties (intensity and wavelength) are correlated with the sensor output characteristics (light-to-dark sensivity, spatial resolution, linearity and S/N ratio). The readout frequency is optimized showing that scans speeds up to 104 lines per second can be achieved without degradation in the resolution. Multilayered p-i'-n-p-i-n heterostructures can also be used as wavelength-division multiplexing /demultiplexing devices in the visible range. Here the sensor element faces the modulated light from different input colour channels, each one with a specific wavelength and bit rate. By reading out the photocurrent at appropriated applied bias, the information is multiplexed or demultiplexed and can be transmitted or recovered again. Electrical models are present to support the sensing methodologies.
Computational evaluation of hydraulic system behaviour with entrapped air under rapid pressurization
Resumo:
The pressurization of hydraulic systems containing entrapped air is considered a critical condition for the infrastructure's security due to transient pressure variations often occurred. The objective of the present study is the computational evaluation of trends observed in variation of maximum surge pressure resulting from rapid pressurizations. The comparison of the results with those obtained in previous studies is also undertaken. A brief state of art in this domain is presented. This research work is applied to an experimental system having entrapped air in the top of a vertical pipe section. The evaluation is developed through the elastic model based on the method of characteristics, considering a moving liquid boundary, with the results being compared with those achieved with the rigid liquid column model.
Resumo:
Business Intelligence (BI) is one emergent area of the Decision Support Systems (DSS) discipline. Over the last years, the evolution in this area has been considerable. Similarly, in the last years, there has been a huge growth and consolidation of the Data Mining (DM) field. DM is being used with success in BI systems, but a truly DM integration with BI is lacking. Therefore, a lack of an effective usage of DM in BI can be found in some BI systems. An architecture that pretends to conduct to an effective usage of DM in BI is presented.