998 resultados para Balanced Trees


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* The research was supported by INTAS 00-397 and 00-626 Projects.

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The k-means algorithm is an extremely popular technique for clustering data. One of the major limitations of the k-means is that the time to cluster a given dataset D is linear in the number of clusters, k. In this paper, we employ height balanced trees to address this issue. Specifically, we make two major contributions, (a) we propose an algorithm, RACK (acronym for RApid Clustering using k-means), which takes time favorably comparable with the fastest known existing techniques, and (b) we prove an expected bound on the quality of clustering achieved using RACK. Our experimental results on large datasets strongly suggest that RACK is competitive with the k-means algorithm in terms of quality of clustering, while taking significantly less time.

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In recent years many real time applications need to handle data streams. We consider the distributed environments in which remote data sources keep on collecting data from real world or from other data sources, and continuously push the data to a central stream processor. In these kinds of environments, significant communication is induced by the transmitting of rapid, high-volume and time-varying data streams. At the same time, the computing overhead at the central processor is also incurred. In this paper, we develop a novel filter approach, called DTFilter approach, for evaluating the windowed distinct queries in such a distributed system. DTFilter approach is based on the searching algorithm using a data structure of two height-balanced trees, and it avoids transmitting duplicate items in data streams, thus lots of network resources are saved. In addition, theoretical analysis of the time spent in performing the search, and of the amount of memory needed is provided. Extensive experiments also show that DTFilter approach owns high performance.

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The consequences of diversity on belowground processes are still poorly known in tropical forests. The distributions of very fine roots (diameter <1 mm) and fine roots (diameter <3 mm) were studied in a randomized block design close to the harvest age of fast-growing plantations. A replacement series was set up in Brazil with mono-specific Eucalyptus grandis (100E) and Acacia mangium (100A) stands and a mixture with the same stocking density and 50 % of each species (50A:50E). The total fine root (FR) biomass down to a depth of 2 m was about 27 % higher in 50A:50E than in 100A and 100E. Fine root over-yielding in 50A:50E resulted from a 72 % rise in E. grandis fine root biomass per tree relative to 100E, whereas A. mangium FR biomass per tree was 17 % lower than in 100A. Mixing A. mangium with E. grandis trees led to a drop in A. mangium FR biomass in the upper 50 cm of soil relative to 100A, partially balanced by a rise in deep soil layers. Our results highlight similarities in the effects of directional resources on leaf and FR distributions in the mixture, with A. mangium leaves below the E. grandis canopy and a low density of A. mangium fine roots in the resource-rich soil layers relative to monospecific stands. The vertical segregation of resource-absorbing organs did not lead to niche complementarity expected to increase the total biomass production. © 2012 Springer-Verlag Berlin Heidelberg.

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A range of influences, both technical and organisational, has encouraged the wide spread adoption of Enterprise Systems (ES). Nevertheless, there is a growing consensus that Enterprise Systems have in many cases failed to provide expected benefits. The increasing role of, and dependency on ES (and IT in general), and the ‘uncertainty’ of these large investments, have created a strong need to monitor and measure ES performance. This paper reports on a research project aimed at deriving an ‘Enterprise Systems benefits measurement instrument’. The research seeks to identify how Enterprise Systems benefits can be usefully measured, with a ‘balance’ between qualitative and quantitative factors.

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The literature on corporate identity management suggests that managing corporate identity is a strategically complex task embracing the shaping of a range of dimensions of organisational life. The performance measurement literature and its applications likewise now also emphasise organisational ability to incorporate various dimensions considering both financial and non-financial performance measures when assessing success. The inclusion of these soft non-financial measures challenges organisations to quantify intangible aspects of performance such as corporate identity, transforming unmeasurables into measurables. This paper explores the regulatory roles of the use of the balanced scorecard in shaping key dimensions of corporate identities in a public sector shared service provider in Australia. This case study employs qualitative interviews of senior managers and employees, secondary data and participant observation. The findings suggest that the use of the balanced scorecard has potential to support identity construction, as an organisational symbol, a communication tool of vision, and as strategy, through creating conversations that self-regulate behaviour. The development of an integrated performance measurement system, the balanced scorecard, becomes an expression of a desired corporate identity, and the performance measures and continuous process provide the resource for interpreting actual corporate identities. Through this process of understanding and mobilising the interaction, it may be possible to create a less obtrusive and more subtle way to control “what an organisation is”. This case study also suggests that the theoretical and practical fusion of the disciplinary knowledge around corporate identities and performance measurement systems could make a contribution to understanding and shaping corporate identities.

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Abstract: Purpose – The purpose of this paper is to provide a parallel review of the role and processes of monitoring and regulation of corporate identities, examining both the communication and the performance measurement literature. Design/methodology/approach – Two questions are posed: Is it possible to effectively monitor and regulate corporate identities as a management control process? and, What is the relationship between corporate identity and performance measurement? Findings – Corporate identity management is positioned as a strategically complex task embracing the shaping of a range of dimensions of organisational life. The performance measurement literature likewise now emphasises organisational ability to incorporate both financial and “soft” non-financial performance measures. Consequently, the balanced scorecard has the potential to play multiple roles in monitoring and regulating the key dimensions of corporate identities. These shifts in direction in both fields suggest that performance measurement systems, as self-producing and self-referencing systems, have the potential to become both organic and powerful as organisational symbols and communication tools. Through this process of understanding and mobilising the interaction of both approaches to management, it may be possible to create a less obtrusive and more subtle way to control the nature of the organisation. Originality/value – This paper attempts the theoretical and practical fusion of disciplinary knowledge around corporate identities and performance measurement systems, potentially making a significant contribution to understanding, shaping and managing organisational identities.

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The work was both conceived and constructed in-situ within Gnombup Swamp a seasonal water body at Bremer Bay, Western Australia. The work interacts with site-specific conditions including wind patterns and a datum of seasonal water levels marks. The work is the result of collaboration between soil scientist Paula Deegan and Ian Weir. The installation was documented with a series of 30 still digital photographs, later animated in Microsoft Powerpoint.