812 resultados para Multi-level Analysis


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Based on the idea of an important cluster, a new multi-level probabilistic neural network (MLPNN) is introduced. The MLPNN uses an incremental constructive approach, i.e. it grows level by level. The construction algorithm of the MLPNN is proposed such that the classification accuracy monotonically increases to ensure that the classification accuracy of the MLPNN is higher than or equal to that of the traditional PNN. Numerical examples are included to demonstrate the effectiveness of proposed new approach.

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We consider two weakly coupled systems and adopt a perturbative approach based on the Ruelle response theory to study their interaction. We propose a systematic way of parameterizing the effect of the coupling as a function of only the variables of a system of interest. Our focus is on describing the impacts of the coupling on the long term statistics rather than on the finite-time behavior. By direct calculation, we find that, at first order, the coupling can be surrogated by adding a deterministic perturbation to the autonomous dynamics of the system of interest. At second order, there are additionally two separate and very different contributions. One is a term taking into account the second-order contributions of the fluctuations in the coupling, which can be parameterized as a stochastic forcing with given spectral properties. The other one is a memory term, coupling the system of interest to its previous history, through the correlations of the second system. If these correlations are known, this effect can be implemented as a perturbation with memory on the single system. In order to treat this case, we present an extension to Ruelle's response theory able to deal with integral operators. We discuss our results in the context of other methods previously proposed for disentangling the dynamics of two coupled systems. We emphasize that our results do not rely on assuming a time scale separation, and, if such a separation exists, can be used equally well to study the statistics of the slow variables and that of the fast variables. By recursively applying the technique proposed here, we can treat the general case of multi-level systems.

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Business and IT alignment is increasingly acknowledged as a key for organisational performance. However, alignment research lack to mechanisms that enable for on-going process with multi-level effects. Multi-level learning allows on-going effectiveness through development of the organisation and improved quality of business and IT strategies. In particular, exploration and exploitation enable effective process of alignment across dynamic multi-level of learning. Hence, this paper proposes a conceptual framework that links multi-level learning and business-IT strategy through the concept of exploration and exploitation, which considers short-term and long-term alignment together to address the challenges of strategic alignment faced in sustaining organisational performance.

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The fungal family Clavicipitaceae includes plant symbionts and parasites that produce several psychoactive and bioprotective alkaloids. The family includes grass symbionts in the epichloae clade (Epichloë and Neotyphodium species), which are extraordinarily diverse both in their host interactions and in their alkaloid profiles. Epichloae produce alkaloids of four distinct classes, all of which deter insects, and some—including the infamous ergot alkaloids—have potent effects on mammals. The exceptional chemotypic diversity of the epichloae may relate to their broad range of host interactions, whereby some are pathogenic and contagious, others are mutualistic and vertically transmitted (seed-borne), and still others vary in pathogenic or mutualistic behavior. We profiled the alkaloids and sequenced the genomes of 10 epichloae, three ergot fungi (Claviceps species), a morning-glory symbiont (Periglandula ipomoeae), and a bamboo pathogen (Aciculosporium take), and compared the gene clusters for four classes of alkaloids. Results indicated a strong tendency for alkaloid loci to have conserved cores that specify the skeleton structures and peripheral genes that determine chemical variations that are known to affect their pharmacological specificities. Generally, gene locations in cluster peripheries positioned them near to transposon-derived, AT-rich repeat blocks, which were probably involved in gene losses, duplications, and neofunctionalizations. The alkaloid loci in the epichloae had unusual structures riddled with large, complex, and dynamic repeat blocks. This feature was not reflective of overall differences in repeat contents in the genomes, nor was it characteristic of most other specialized metabolism loci. The organization and dynamics of alkaloid loci and abundant repeat blocks in the epichloae suggested that these fungi are under selection for alkaloid diversification. We suggest that such selection is related to the variable life histories of the epichloae, their protective roles as symbionts, and their associations with the highly speciose and ecologically diverse cool-season grasses.

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The planning of semi-autonomous vehicles in traffic scenarios is a relatively new problem that contributes towards the goal of making road travel by vehicles free of human drivers. An algorithm needs to ensure optimal real time planning of multiple vehicles (moving in either direction along a road), in the presence of a complex obstacle network. Unlike other approaches, here we assume that speed lanes are not present and that different lanes do not need to be maintained for inbound and outbound traffic. Our basic hypothesis is to carry forward the planning task to ensure that a sufficient distance is maintained by each vehicle from all other vehicles, obstacles and road boundaries. We present here a 4-layer planning algorithm that consists of road selection (for selecting the individual roads of traversal to reach the goal), pathway selection (a strategy to avoid and/or overtake obstacles, road diversions and other blockages), pathway distribution (to select the position of a vehicle at every instance of time in a pathway), and trajectory generation (for generating a curve, smooth enough, to allow for the maximum possible speed). Cooperation between vehicles is handled separately at the different levels, the aim being to maximize the separation between vehicles. Simulated results exhibit behaviours of smooth, efficient and safe driving of vehicles in multiple scenarios; along with typical vehicle behaviours including following and overtaking.

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The response of monsoon circulation in the northern and southern hemisphere to 6 ka orbital forcing has been examined in 17 atmospheric general circulation models and 11 coupled ocean–atmosphere general circulation models. The atmospheric response to increased summer insolation at 6 ka in the northern subtropics strengthens the northern-hemisphere summer monsoons and leads to increased monsoonal precipitation in western North America, northern Africa and China; ocean feedbacks amplify this response and lead to further increase in monsoon precipitation in these three regions. The atmospheric response to reduced summer insolation at 6 ka in the southern subtropics weakens the southern-hemisphere summer monsoons and leads to decreased monsoonal precipitation in northern South America, southern Africa and northern Australia; ocean feedbacks weaken this response so that the decrease in rainfall is smaller than might otherwise be expected. The role of the ocean in monsoonal circulation in other regions is more complex. There is no discernable impact of orbital forcing in the monsoon region of North America in the atmosphere-only simulations but a strong increase in precipitation in the ocean–atmosphere simulations. In contrast, there is a strong atmospheric response to orbital forcing over northern India but ocean feedback reduces the strength of the change in the monsoon although it still remains stronger than today. Although there are differences in magnitude and exact location of regional precipitation changes from model to model, the same basic mechanisms are involved in the oceanic modulation of the response to orbital forcing and this gives rise to a robust ensemble response for each of the monsoon systems. Comparison of simulated and reconstructed changes in regional climate suggest that the coupled ocean–atmosphere simulations produce more realistic changes in the northern-hemisphere monsoons than atmosphere-only simulations, though they underestimate the observed changes in precipitation in all regions. Evaluation of the southern-hemisphere monsoons is limited by lack of quantitative reconstructions, but suggest that model skill in simulating these monsoons is limited.

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We investigate the role of the ocean feedback on the climate in response to insolation forcing during the mid-Holocene (6,000 year BP) using results from seven coupled ocean–atmosphere general circulation models. We examine how the dipole in late summer sea-surface temperature (SST) anomalies in the tropical Atlantic increases the length of the African monsoon, how this dipole structure is created and maintained, and how the late summer SST warming in the northwest Indian Ocean affects the monsoon retreat in this sector. Similar mechanisms are found in all of the models, including a strong wind evaporation feedback and changes in the mixed layer depth that enhance the insolation forcing, as well as increased Ekman transport in the Atlantic that sharpens the Atlantic dipole pattern. We also consider changes in interannual variability over West Africa and the Indian Ocean. The teleconnection between variations in SST and Sahelian precipitation favor a larger impact of the Atlantic dipole mode in this region. In the Indian Ocean, the strengthening of the Indian dipole structure in autumn has a damping effect on the Indian dipole mode at the interannual time scale

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This study represents the first detailed multi-proxy palaeoenvironmental investigation associated with a Late Iron Age lake-dwelling site in the eastern Baltic. The main objective was to reconstruct the environmental and vegetation dynamics associated with the establishment of the lake-dwelling and land-use during the last 2,000 years. A lacustrine sediment core located adjacent to a Late Iron Age lake-dwelling, medieval castle and Post-medieval manor was sampled in Lake Āraiši. The core was dated using spheroidal fly-ash particles and radiocarbon dating, and analysed in terms of pollen, non-pollen palynomorphs, diatoms, loss-on-ignition, magnetic susceptibility and element geochemistry. Associations between pollen and other proxies were statistically tested. During ad 1–700, the vicinity of Lake Āraiši was covered by forests and human activities were only small-scale with the first appearance of cereal pollen (Triticum and Secale cereale) after ad 400. The most significant changes in vegetation and environment occurred with the establishment of the lake-dwelling around ad 780 when the immediate surroundings of the lake were cleared for agriculture, and within the lake there were increased nutrient levels. The highest accumulation rates of coprophilous fungi coincide with the occupation of the lake-dwelling from ad 780–1050, indicating that parts of the dwelling functioned as byres for livestock. The conquest of tribal lands during the crusades resulted in changes to the ownership, administration and organisation of the land, but our results indicate that the form and type of agriculture and land-use continued much as it had during the preceding Late Iron Age.

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At Hollow Banks Quarry, Scorton, located just north of Catterick (N Yorks.), a highly unusual group of 15 late Roman burials was excavated between 1998 and 2000. The small cemetery consists of almost exclusively male burials, dated to the fourth century. An unusually large proportion of these individuals was buried with crossbow brooches and belt fittings, suggesting that they may have been serving in the late Roman army or administration and may have come to Scorton from the Continent. Multi-isotope analyses (carbon, nitrogen, oxygen and strontium) of nine sufficiently well-preserved individuals indicate that seven males, all equipped with crossbow brooches and/or belt fittings, were not local to the Catterick area and that at least six of them probably came from the European mainland. Dietary (carbon and nitrogen isotope) analysis only of a tenth individual also suggests a non-local origin. At Scorton it appears that the presence of crossbow brooches and belts in the grave was more important for suggesting non-British origins than whether or not they were worn. This paper argues that cultural and social factors played a crucial part in the creation of funerary identities and highlights the need for both multi-proxy analyses and the careful contextual study of artefacts.

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We demonstrate that stakeholder-oriented multi-criteria analysis (MCA) can adequately address a variety of sustainable development dilemmas in decision-making, especially when applied to complex project evaluations involving multiple objectives and multiple stakeholder groups. Such evaluations are typically geared towards satisfying simultaneously private economic goals, broader social objectives and environmental targets. We show that, under specific conditions, a variety of stakeholder-oriented MCA approaches may be able to contribute substantively to the resolution or improved governance of societal conflicts and the pursuit of the public good in the form of sustainable development. We contrast the potential usefulness of these stakeholder-oriented approaches – in terms of their ability to contribute to sustainable development – with more conventional MCA approaches and social cost–benefit analysis.

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The optimal formulation for the preparation of amaranth flour films plasticized with glycerol and sorbitol was obtained by a multi-response analysis. The optimization aimed to achieve films with higher resistance to break, moderate elongation and lower solubility in water. The influence of plasticizer concentration (Cg, glycerol or Cs, sorbitol) and process temperature (Tp) on the mechanical properties and solubility of the amaranth flour films was initially studied by response surface methodology (RSM). The optimized conditions obtained were Cg 20.02 g glycerol/100 g flour and Tp 75 degrees C, and Cs 29.6 g sorbitol/100 g flour and Tp 75 degrees C. Characterization of the films prepared with these formulations revealed that the optimization methodology employed in this work was satisfactory. Sorbitol was the most suitable plasticizer. It furnished amaranth flour films that were more resistant to break and less permeable to oxygen, due to its greater miscibility with the biopolymers present in the flour and its lower affinity for water. (C) 2011 Elsevier Ltd. All rights reserved.

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In this paper we study the interaction between macroeconomic environment and firms’ balance sheet effects in Brazil during the 1990’s. We start by assessing the influence of macroeconomic conditions on firms’ debt composition in Brazil. We found that larger firms tend to change debt currency composition more in response to a change in the exchange rate risk than small firms. We then proceed to investigate if and how exchange rate balance sheet effects affected the firms’ investment decisions. We test directly the exchange rate balance sheet effect on investment. Contrary to earlier findings (Bleakley and Cowan, 2002), we found that firms more indebted in foreign currency tend to invest less when there is an exchange rate devaluation. We tried different controls for the competitiveness effect. First, we control directly for the effect of the exchange rate on exports and imported inputs. We then pursue an alternative investigation strategy, inspired by the credit channel literature. According to this perspective, Tobin’s q can provide an adequate control for the competitiveness effect on investment. Our results provide supporting evidence for imperfect capital markets, and for a negative exchange rate balance sheet effect in Brazil. The results concerning the exchange rate balance sheet effect on investment are statistically significant and robust across the different specifications. We tested the results across different periods, classified according to the macroeconomic environment. Our findings suggest that the negative exchange rate balance sheet effect we found in the whole sample is due to the floating exchange rate period. We also found that exchange rate devaluations have important negative impact on both cash flows and sales of indebted firms. Furthermore, the impact of exchange rate variations is asymmetric, and the significant effect detected when no asymmetry is imposed is engendered by exchange rate devaluations.

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As primeiras regiões metropolitanas brasileiras foram instituídas de maneira vertical e autoritária como parte da estratégia de desenvolvimento nacional promovida pelo governo militar. Percebidas como instituições não-democráticas e rejeitadas como possível quarto ente federativo, as regiões metropolitanas, desde a Constituição de 1988, foram gradualmente esvaziadas dos seus propósitos originais. Em sua orfandade, os problemas socioeconômicos proliferaram e foram acentuados, e passaram a predominar relações intergovernamentais competitivas em vez de cooperativas. Um dos principais desafios enfrentados pelo modelo federalista brasileiro, em especial quando se trata destas regiões, está relacionado à necessidade de estabelecer maior cooperação e coordenação, tidas como imprescindíveis para garantir um relacionamento mais equilibrado entre os entes federativos, assim como para a efetiva implementação de políticas de enfrentamento das desigualdades e exclusão social nas aglomerações urbanas. Este trabalho analisa o Grande Recife Consórcio Metropolitano de Transportes (CMT), empresa pública multifederativa estabelecida em 2008 entre os governos municipais e estadual da Região Metropolitana de Recife (RMR). Responsável pelo planejamento, gestão e implementação compartilhada da política de transporte público coletivo na RMR, o Grande Recife se tornou realidade com a aprovação e regulamentação da Lei Federal nº 11.107 de 2005, conhecida como a Lei de Consórcios Públicos. O Grande Recife é uma experiência pioneira e inovadora, demonstrando que é possível encontrar uma maneira de superar conflitos e desafios comuns e, ao mesmo tempo, garantir a preservação da autonomia de cada ente, bem como os direitos cidadãos. Neste trabalho consideramos essa experiência de cooperação intergovernamental como um exemplo de multi-level governance (MLG), uma vez que é ilustrativa de um novo arranjo institucional democrático entre distintas esferas governamentais para a gestão compartilhada de um serviço público.

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Poverty in Brazil has been gradually reduced. Among the main reasons, there are public policies for universalization of rights. On the other hand, the municipalities' Human Development Index indicates scenarios of growing inequality. In other words, some regions, basically of rural character, were left behind in that process of development. In 2008, the “Territórios da Cidadania” (Territories of Citizenship) Program was launched by the federal government, under high expectations. It was proposed to develop those regions and to prioritize the arrival of ongoing federal public policies where they were most demanded. The program has shown an innovative arrangement which included dozens of ministries and other federal agencies, state governments, municipalities and collegialities to the palliative management and control of the territory. In this structure, both new and existing jurisdictions came to support the program coordination. This arrangement was classified as an example of multi-level governance, whose theory has been an efficient instrument to understand the intra- and intergovernmental relations under which the program took place. The program lasted only three years. In Vale do Ribeira Territory – SP, few community leaderships acknowledge it, although not having further information about its actions and effects. Against this background, the approach of this research aims to study the program coordination and governance structure (from Vale Territory, considered as the most local level, until the federal government), based on the hypothesis that, beyond the local contingencies in Vale do Ribeira, the layout and implementation of the Territories of Citizenship Program as they were formulated possess fundamental structural issues that hinder its goals of reducing poverty and inequality through promoting the development of the territory. Complementing the research, its specific goal was to raise the program layout and background in order to understand how the relations, predicted or not in its structure, were formulated and how they were developed, with special attention to Vale do Ribeira-SP. Generally speaking, it was concluded that the coordination and governance arrangement of the Territories of Citizenship Program failed for not having developed qualified solutions to deal with the challenges of the federalist Brazilian structure, party politics, sectorized public actions, or even the territory contingencies and specificities. The complexity of the program, the poverty problem proposed to be faced, and the territorial strategy of development charged a high cost of coordination, which was not accomplished by the proposal of centralization in the federal government with internal decentralization of the coordination. As the presidency changed in 2011, the program could not present results that were able to justify the arguments for its continuation, therefore it was paralyzed, lost its priority status, and the resources previously invested were redirected.

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The present paper proposes a new hybrid multi-population genetic algorithm (HMPGA) as an approach to solve the multi-level capacitated lot sizing problem with backlogging. This method combines a multi-population based metaheuristic using fix-and-optimize heuristic and mathematical programming techniques. A total of four test sets from the MULTILSB (Multi-Item Lot-Sizing with Backlogging) library are solved and the results are compared with those reached by two other methods recently published. The results have shown that HMPGA had a better performance for most of the test sets solved, specially when longer computing time is given. © 2012 Elsevier Ltd.