892 resultados para Simplification of Ontologies
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QUT Library Research Support has simplified and streamlined the process of research data management planning, storage, discovery and reuse through collaboration and the use of integrated and tailored online tools, and a simplification of the metadata schema. This poster presents the integrated data management services a QUT, including QUT’s Data Management Planning Tool, Research Data Finder, Spatial Data Finder and Software Finder, and information on the simplified Registry Interchange Format – Collections and Services (RIF-CS) Schema. The QUT Data Management Planning (DMP) Tool was built using the Digital Curation Centre’s DMP Online Tool and modified to QUT’s needs and policies. The tool allows researchers and Higher Degree Research students to plan how to handle research data throughout the active phase of their research. The plan is promoted as a ‘live’ document’ and researchers are encouraged to update it as required. The information entered into the plan can be made private or shared with supervisors, project members and external examiners. A plan is mandatory when requesting storage space on the QUT Research Data Storage Service. QUT’s Research Data Finder is integrated with QUT’s Academic Profiles and the Data Management Planning Tool to create a seamless data management process. This process aims to encourage the creation of high quality rich records which facilitate discovery and reuse of quality data. The Registry Interchange Format – Collections and Services (RIF-CS) Schema that is used in the QUT Research Data Finder was simplified to “RIF-CS lite” to reflect mandatory and optional metadata requirements. RIF-CS lite removed schema fields that were underused or extra to the needs of the users and system. This has reduced the amount of metadata fields required from users and made integration of systems a far more simple process where field content is easily shared across services making the process of collecting metadata as transparent as possible.
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It is well known that the notions of normal forms and acyclicity capture many practical desirable properties for database schemes. The basic schema design problem is to develop design methodologies that strive toward these ideals. The usual approach is to first normalize the database scheme as far as possible. If the resulting scheme is cyclic, then one tries to transform it into an acyclic scheme. In this paper, we argue in favor of carrying out these two phases of design concurrently. In order to do this efficiently, we need to be able to incrementally analyze the acyclicity status of a database scheme as it is being designed. To this end, we propose the formalism of "binary decompositions". Using this, we characterize design sequences that exactly generate theta-acyclic schemes, for theta = agr,beta. We then show how our results can be put to use in database design. Finally, we also show that our formalism above can be effectively used as a proof tool in dependency theory. We demonstrate its power by showing that it leads to a significant simplification of the proofs of some previous results connecting sets of multivalued dependencies and acyclic join dependencies.
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With respect to resource management and environmental impact, organic farming offers rationales for agricultural sustainability. However, agronomic productivity is usually higher with conventional farming. This work aimed at investigating two factors of major importance for the agronomic productivity of organic crop husbandry, nitrogen (N) supply through symbiotic N fixation (SNF) and weed occurrence. Perennial red clover-grass leys and spring cereal crops subjected to regular agricultural practices were studied on 34 organic farms located in the southern and the north-western coastal regions of Finland. Herbage growth, clover content as a proportion of the ley and extent of SNF in perennial leys, and the occurrence of weed species and weed-crop competition in spring cereal stands were related to climate conditions, soil properties, and management measures. The herbage accumulated from the first and the second cut of one- and two-year-old leys averaged 7.5 t DM ha-1 (SD ± 1.7 t DM ha-1); the clover content averaged 43.9% (SD ± 18.8%). Along with the clover content, herbage production decreased with ley age. Radiation use efficiency (RUE) correlated positively with clover proportion but despite low clover contents, three-year-old leys were still productive with regard to RUE. SNF in the accumulated annual growth of one- and two-year-old leys averaged 247.5 kg N ha-1 yr-1 (SD ± 114.4 kg N ha-1 yr-1). It was supposed that if red clover-grass leys constituted 40% of the rotation, then the mean N supply by SNF would be able to sustain two or three succeeding cereal crops (green manure and forage ley, respectively), yielding 3.0 to 4.0 t grain ha-1. Being a function of clover biomass, the SNF increased from the first to the second cut and thereafter declined with ley age. Coefficients of variation of clover contents (and SNF) between and within fields were around 50%, which was about twice as high as those of herbage production. The lower were the clover contents, the higher were the within-field variations of clover as a proportion of the ley. Low clover contents in one-year-old leys and increasing variability with ley age suggested that red clover growth was limited by poor establishment and poor overwintering. The proportions of clover in leys were lower and their variability was higher in the northwest than in the south. Soil properties, primarily texture and structure, had a major impact on clover proportion and herbage production, which largely explained regional differences in ley growth. Within-field variability of soil properties can be amended through site-specific measures, including drainage, liming, and applications of organic manures and mineral fertilizers. Overwintering and the persistence of leys can be improved by the choice of winter-hardy varieties, careful establishment and the appropriate harvest regime. Mean grain yields of spring cereal crops amounted to 3.2 t ha-1 in the south and 3.6 t ha-1 in the northwest. At 570 and 565 m-2 for the south and northwest respectively, mean weed densities did not differ between the regions, whereas the respective mean weed biomass of 697 and 1594 kg dry weight ha-1, respectively did differ. Weed abundance varied remarkably between single fields. The number of weed species was higher in the south than in the northwest. For example, Fumaria officinalis and Lamium spp. were found only in the south. Frequencies and abundances of Lapsana communis, Myosotis arvensis, Polygonum aviculare, Tripleurospermum inodorum, and Vicia spp. were higher in the south, whereas those of Elymus repens, Persicaria spp. and Spergula arvensis were higher in the northwest. The number of years since conversion to organic farming, i.e. long-term management, was one of the variables that explained the abundance of single weed species. E. repens was the weed species whose biomass increased most with the duration of organic farming. Another significant variable was crop biomass, which was affected by short-term management. The presence of different weed species was related to the duration of organic farming and to low crop yield. This finding demonstrated that it was not the organic farming regime per se, which resulted in high weed infestation and low yielding crops, but failures in the understanding and the management of organic farming systems. Successful weed control relies on farm- and field-specific long- and short-term management approaches. The agronomic productivity of ley and spring cereal crops managed by full-time farmers with an interest in organic farming was on the same level as of the mean for conventional farming. Given the many options for further improvements of the agronomic performance of organic arable systems, organic farming offers foundations for the development of sustainable agriculture. The main threat to the sustainability of farming in Finland, both conventional and organic, is the spatial separation of crop production and animal husbandry by region, along with the simplification of associated crop rotations.
Resumo:
Intensification of agricultural land-use has been was shown to be the key reason behind declines in wildlife species associated with farmland. Accession to the European Union is regarded as a potential threat to the farmland biota of its new member states. In my thesis I looked at scenarios of agricultural development across the Baltic states of Estonia, Latvia and Lithuania, and the ways they are seen to affect farmed environments as a habitat of farmland bird species. I looked at the effects of major farmed habitats across the region, and assessed the role of spatial organisation of farmed habitats. I also evaluated the direction and magnitude of changes in bird communities following progression of farmland land-use from a relatively less intensive to the most intensive type within each country. Different aspects of the structural complexity of farmland were critical for supporting farmland birds. There was a clear indication that the more intensively farmed areas across the region provided habitat for fewer bird species and individuals, and intensification of field management was reflected in a tangible decrease in farmland bird abundance. The second part of the thesis, based on interviews in Estonia and Finland, is devoted to farmers interest in and knowledge of farmland wildlife, their understanding of the concept of biodiversity, and awareness of causes behind species declines. I examined the relationship between farmers interest and their willingness to undertake practices favouring farmland wildlife. Many farmers viewed biodiversity from a narrow perspective. In Finland farmers expressed higher concern about the decline in common farmland species than in Estonia. In both countries farmers rated intensification of agriculture as the major driving force behind declines. The expressed interest in wildlife positively correlated with willingness to undertake wildlife-friendly measures. Only farmers with agri-environment contracts targeted specifically at biodiversity were more knowledgeable about practical on-farm activities favouring wildlife, and were more willing to employ them that the rest. The results suggest that, by contributing to simplification of the farmland structure, homogenisation of crops, and increase in intensity of field use, EU agricultural policies will have a detrimental effect on farmland bird populations in Eastern Europe. Farmers are on the whole positive to the idea of supporting wildlife on their farms, and are concerned about declines, but they require payments to offset their income loss and extra work. I propose ways of further improving and better targeting of the agri-environment schemes in the region. I argue that with a foreseen tripling of cereal yields across the region, the EU Council s target of halting biodiversity decline in the EU by 2010 may not be realistic unless considerable improvements are made in conservation safeguards within the EU agricultural policy for the region.
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Topic detection and tracking (TDT) is an area of information retrieval research the focus of which revolves around news events. The problems TDT deals with relate to segmenting news text into cohesive stories, detecting something new, previously unreported, tracking the development of a previously reported event, and grouping together news that discuss the same event. The performance of the traditional information retrieval techniques based on full-text similarity has remained inadequate for online production systems. It has been difficult to make the distinction between same and similar events. In this work, we explore ways of representing and comparing news documents in order to detect new events and track their development. First, however, we put forward a conceptual analysis of the notions of topic and event. The purpose is to clarify the terminology and align it with the process of news-making and the tradition of story-telling. Second, we present a framework for document similarity that is based on semantic classes, i.e., groups of words with similar meaning. We adopt people, organizations, and locations as semantic classes in addition to general terms. As each semantic class can be assigned its own similarity measure, document similarity can make use of ontologies, e.g., geographical taxonomies. The documents are compared class-wise, and the outcome is a weighted combination of class-wise similarities. Third, we incorporate temporal information into document similarity. We formalize the natural language temporal expressions occurring in the text, and use them to anchor the rest of the terms onto the time-line. Upon comparing documents for event-based similarity, we look not only at matching terms, but also how near their anchors are on the time-line. Fourth, we experiment with an adaptive variant of the semantic class similarity system. The news reflect changes in the real world, and in order to keep up, the system has to change its behavior based on the contents of the news stream. We put forward two strategies for rebuilding the topic representations and report experiment results. We run experiments with three annotated TDT corpora. The use of semantic classes increased the effectiveness of topic tracking by 10-30\% depending on the experimental setup. The gain in spotting new events remained lower, around 3-4\%. The anchoring the text to a time-line based on the temporal expressions gave a further 10\% increase the effectiveness of topic tracking. The gains in detecting new events, again, remained smaller. The adaptive systems did not improve the tracking results.
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Centred space vector PWM (CSVPWM) technique is popularly used for three level voltage source inverters. The reference voltage vector is synthesized by time-averaging of the three nearest voltage vectors produced by the inverter. Identifying the three voltage vectors, and calculation of the dwelling time for each vector are both computationally intensive. This paper analyses the process of PWM generation in CSVPWM. This analysis breaks up a three-level inverter into six different conceptual two level inverters in different regions of the fundamental cycle. Control of 3-level inverter is viewed as the control of the appropriate 2-level inverter. The analysis leads to a systematic simplification of the computations involved, finally resulting in a computationally efficient PWM algorithm. This algorithm exploits the equivalence between triangle comparison and space vector approaches to PWM generation. This algorithm does not involve any 3-phase/2-phase or 2-phase/3-phase transformation. This also does not involve any transformation from rectangular to polar coordinates, and vice versa. Further no evaluation of trigonometric functions is necessary. This algorithm also provides for the mitigation of DC neutral point unbalance, and is well suited to digital implementation. Simulation and experimental results are presented.
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Principles of design of composite instantaneous comparators (a combination of amplitude- and phase- comparison techniques) are laid out to provide directional, directional-reactance, nonoffset-resistance and conductance characteristices. The respective signals provided by the voltage transformer and the current transformer are directly used as relaying signals without resorting to any form of mixing. Phase shifts required, are obtained by using magnetic ferrite cores in a novel manner. Sampling units employing a combination of ferrite cores and semiconductor devices provide highly reliable designs. Special attention is paid to the choice of relaying signals, to eliminate the need for any synchronisation or modification and to avoid `image¿ characteristics. These factors have resulted in a considerable simplification of the practical circuitry. A thyristor AND circuit is employed in dual comparator units to provide the final tripping, and leads to a circuit which is much less sensitive to extraneous signals than a single-thyristor unit.
Resumo:
研究强粘性剪切流稳定性方程组的物理尺度及其相互关系.同时,对强粘性剪切流稳定性方程组作GCS分析,从而解决强粘性剪切流稳定性方程组的某些计算问题.作为应用,给出Orr-Sommerfeld方程的一种新的简化形式.
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Kilometer scale interferometers for the detection of gravitational waves are currently under construction by the LIGO (Laser Interferometer Gravitational-wave Observatory) and VIRGO projects. These interferometers will consist of two Fabry-Perot cavities illuminated by a laser beam which is split in half by a beam splitter. A recycling mirror between the laser and the beam splitter will reflect the light returning from the beam splitter towards the laser back into the interferometer. The positions of the optical components in these interferometers must be controlled to a small fraction of a wavelength of the laser light. Schemes to extract signals necessary to control these optical components have been developed and demonstrated on the tabletop. In the large scale gravitational wave detectors the optical components must be suspended from vibration isolation platforms to achieve the necessary isolation from seismic motion. These suspended components present a new class of problems in controlling the interferometer, but also provide more exacting test of interferometer signal and noise models.
This thesis discusses the first operation of a suspended-mass Fabry-Perot-Michelson interferometer, in which signals carried by the optically recombined beams are used to detect and control all important mirror displacements. This interferometer uses an optical configuration and signal extraction scheme that is planned for the full scale LIGO interferometers with the simplification of the removal of the recycling mirror. A theoretical analysis of the performance that is expected from such an interferometer is presented and the experimental results are shown to be in generally good agreement.
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Aplicações cientes de contexto precisam de mecanismos para recuperar informações sobre o seu contexto de execução. Com base no contexto atual, tais aplicações são capazes de se autoadaptar para fornecer informações e serviços adequados aos seus usuários. A abordagem comum para infraestruturas de apoio às aplicações sensíveis ao contexto fornece serviços para a descoberta de recursos através da utilização de pares
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[eus] Azken urteetako teknologia berrien iraultza dela eta, haur eta gazte literaturak bere forma aldatu du, ikus-entzunezko euskarrietara moldatuz, hartzaile haurrei erakargarriago eta ulergarriago suertatzearren. Adibide moduan Momo eleberria hartuta, bere moldaketa zinematografikorako erabili diren estrategiak aztertu dira eta bi adierazpen-euskarrien tramak konparatu dira. Analisi honen bidez frogatu ahal izan da moldaketa mota hauek, hain zuzen, jatorrizko lanaren sinplifikazioa inplikatzen dutela; hala ere, ez da arrazoi nahikoa hauek alde batera uzteko edo mesprezatzeko eta hezkuntza-baliabide posible gisa baztertzeko.
Resumo:
A presente dissertação se propõe a contribuir para as análises dos processos ligados à implementação das leis 10639/03 e 11645/08. Questionamo-nos acerca dos desdobramentos do imperativo das leis nos livros didáticos de história, sobretudo, no uso do conceito de colonizador no processo de explicação da relação entre diferentes povos e culturas nas coleções da disciplina história. Como estão descritas essas relações? Há mudanças institucionalizadas pelo PNLD ou pelas leis: que descrições de significados culturais, políticos os sujeitos implicados nos eventos de ocupação do território americano são apresentados nos manuais de ensino de história? Buscamos entender quais as relações de colonialidade do saber se estabelecem na sistematização dos conteúdos de história, tendo em vista que os atos de colonização envolvem dinâmicas que se chocam com as premissas hierárquicas simplificadas nos processos de ensino de história na escola de acordo com as descrições dos livros didáticos. As maneiras pelas quais o colonizador é rotulado como conquistador, supervalorizando a dimensão europeia do processo e subvalorizando os referenciais da cultura local representados nos povos pré-colombianos são problematizadas nessa dissertação sob duas perspectivas: (1) a superficialização das relações hierárquicas nos processos de colonização, dessa forma, inscrita no feixe de possibilidades que corrobora com as estratégias de perpetuação das simplificações das funções dos atores sociais no período colonial descritas nos manuais didáticos de história; (2) ou como reação prática ou simplista, como estratégia que modifica a realidade histórica social ao sabor das conveniências políticas, suas relações de poder e desenvolvimento de políticas públicas. A pesquisa fundamentou-se na análise de uma coleção de livro didático de história para o ensino médio (1 ao 3 anos) mais usadas efetivamente nas escolas públicas do município de Cabo Frio, Estado do Rio de Janeiro. A pesquisa delimita dois eixos, o primeiro, por meio da análise do histórico das legislações 10639/03 e 11645/08, leis nas quais são baseadas as regulamentações sobre o ensino étnico-racial e grande parte das discussões sobre ações afirmativas no Brasil; um segundo, no qual se estabeleceu investigação aos sentidos atribuídos ao que se define como colonizador e a percepção de quais são as descrições classificadas como colonialidade do saber histórico nos livros didáticos. Tal discussão sobre o colonizador pode contribuir na reflexão crítica sobre a institucionalização do saber histórico escolar do livro didático e de normalização nacional como os PNLDs, quanto às disputas de poder que ocorrem entre os atores políticos no processo de justificativa histórica das políticas públicas como as ações afirmativas.
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Geração e Simplificação da Base de Conhecimento de um Sistema Híbrido Fuzzy- Genético propõe uma metodologia para o desenvolvimento da base de conhecimento de sistemas fuzzy, fundamentada em técnicas de computação evolucionária. Os sistemas fuzzy evoluídos são avaliados segundo dois critérios distintos: desempenho e interpretabilidade. Uma metodologia para a análise de problemas multiobjetivo utilizando a Lógica Fuzzy foi também desenvolvida para esse fim e incorporada ao processo de avaliação dos AGs. Os sistemas fuzzy evoluídos foram avaliados através de simulações computacionais e os resultados obtidos foram comparados com os obtidos por outros métodos em diferentes tipos de aplicações. O uso da metodologia proposta demonstrou que os sistemas fuzzy evoluídos possuem um bom desempenho aliado a uma boa interpretabilidade da sua base de conhecimento, tornando viável a sua utilização no projeto de sistemas reais.
Resumo:
由于计划调度问题本身的复杂性,很难寻求到最优解。从简化问题和满足加工系统实时性的要求,近年来提出各种解法,但由于这些方法的背景和目标不同。使其在性能上很难作出比较,这也正是仿真技术在此方面得到普遍应用的主要原因。该文就此介绍了一个基于多单元的并行仿真系统。
Resumo:
In the petroleum exploration industry, it is very important to simulate the evolvement of wave field beneath our earth in the aspects of time and space quickly and effectively. Because of the huge data size in petroleum exploration and also the strict requirement of time limit in the actual process of production, simplification of models and approximation of algorithm are necessary. At the same time, every fine improvement to algorithm has its great practical significance and use value. Based on the reasons above, this dissertation researches the separable approximation methods of space-wave number domain for One-way Wave Operator and gets the conclusions as follow: 1. It is insufficient to value One-way Wave Operator purely from the mathematical modulus and phase error, while, holding some specific structural character of operator should be more important. Because, the evaluation criterion of One-way Wave Operator’s imaging ability is quite complicate and obscured, which is similar to the evaluation of an artwork. 2. We can not search for a best or most effective One-way Wave Operator approximation solution for all. However, to different speed model and precision requirement the best approximation solution does exist which is maybe also a compromise, because it is very beneficial to One-way Wave Operator to take full advantage of speed model’s pre-tested information.