Intelligent search for distributed information sources using heterogeneous neural networks

As the number and diversity of distributed information sources on the Internet exponentially increase, various search services are developed to help the users to locate relevant information. But they still exist some drawbacks such as the difficulty of mathematically modeling retrieval process, the lack of adaptivity and the indiscrimination of search. This paper shows how heteroge-neous neural networks can be used in the design of an intelligent distributed in-formation retrieval (DIR) system. In particular, three typical neural network models - Kohoren's SOFM Network, Hopfield Network, and Feed Forward Network with Back Propagation algorithm are introduced to overcome the above drawbacks in current research of DIR by using their unique properties. This preliminary investigation suggests that Neural Networks are useful tools for intelligent search for distributed information sources

A multi-layered Bayesian network model for structured document retrieval

New standards in document representation, like for example SGML, XML, and MPEG-7, compel Information Retrieval to design and implement models and tools to index, retrieve and present documents according to the given document structure. The paper presents the design of an Information Retrieval system for multimedia structured documents, like for example journal articles, e-books, and MPEG-7 videos. The system is based on Bayesian Networks, since this class of mathematical models enable to represent and quantify the relations between the structural components of the document. Some preliminary results on the system implementation are also presented

Ranking structured documents using utility theory in the Bayesian network retrieval model

In this paper a new method based on Utility and Decision theory is presented to deal with structured documents. The aim of the application of these methodologies is to refine a first ranking of structural units, generated by means of an Information Retrieval Model based on Bayesian Networks. Units are newly arranged in the new ranking by combining their posterior probabilities, obtained in the first stage, with the expected utility of retrieving them. The experimental work has been developed using the Shakespeare structured collection and the results show an improvement of the effectiveness of this new approach

Produção de Tifton 85 no primeiro ciclo de pastejo em área irrigada e de sequeiro: 2012/2013.

Salão do conhecimento

Spatial Distribution of Dung in Integrated Dairy Systems

Animals in grazing work as catalyst in the nutrient cycling processes of the ecosystems. Part of biomass that animal intake returning to soil in the degraded way like faeces and urine. The return is around 90% of the mineral nutrients, including nitrogen. However, it is necessary to know how these dejects are distributed on the area by animals. The environment management affects directly spatial distribution of these dejects. Drinking fountain, salt and feed trough, portress, rest area and shadow are structures that change the way that animal graze. Sward structure and herbage morphology affect the grazing behaviour as well. So, the objective this experiment was evaluate the spatial distribution of dung from dairy heifers in integrated systems of production at Mato Grosso, Brazil. The experiment was accomplished at Embrapa (Sinop/Mato Grosso/ Brazil). The experimental area was 10 ha divided in three systems: full sun, marginal shadowing (300 trees per ha) and intensive shadowing (750 trees per ha). Each system had different sizes, but 2.4 ha was useful area for all systems divided in 10 paddocks each. The tree used was Eucalyptus urograndis, H13 clone and the pasture was piata Grass (Urochloa brizantha). The grazing was done when the sward reached 95% light interception. It was evaluated a group of 24 breed heifers with 350 kg in three periods of year. Each paddock was divided in 25 grids for count of faeces boards. The spatial faeces distribution was evaluated with GPS, by walking and capturing points where there was faeces boards in all steps for the grassland paddocks, in three periods of year (rainy, rainy-drought transition and dry period). The dataset was analysed by SAS 9.2 version, using PROC MIXED and PDIFF to 5% of significance. The spatial distribution of dung had significant difference only in rainy-drought transition period (P=0.0165) and interaction effect between shadowing and site (P=0.0025) in this period of year and dry period as well (P=0. 0465). In both periods, the distribution was the same. The full sun system promoted more concentration of faeces boards in sites next portress and border fence in site opposite to portress. In marginal shadowing system, the major concentration was in the central area and under shadow. In intensive shadowing system, the major concentration of dung boards was under shadow, sites preferred by heifers for rumination and leisure activities. The kind of shade and the year periods affected in spatial dung distribution. There were places with more dung concentration, in all kind of shade, but when the pasture had the intensive shade, the dispersion was more homogeneous. Unlike expected, the dung deposition didn?t happens only under treetops. The distribution is more homogeneous when trees are in large quantities. The shadow area available in the grassland affected the spatial dung distribution, and can be more homogeneous than no shadow

European Respiratory Society Statement on Long COVID-19 Follow-Up

Patients diagnosed with COVID-19 associated with SARS-CoV-2 infection frequently experience symptom burden post-acute infection or post-hospitalisation. We aim to identify optimal strategies for follow-up care that may positively impact the patient's quality-of-life (QOL).A European Respiratory Society (ERS) Task Force (TF) convened and prioritised eight clinical questions. A targeted search of the literature defined the time line of long COVID-19 as one to six months post infection and identified clinical evidence in the follow-up of patients. Studies meeting the inclusion criteria report an association of characteristics of acute infection with persistent symptoms, thromboembolic events in the follow-up period and evaluations of pulmonary physiology and imaging. Importantly, this statement reviews QOL consequences, symptom burden, disability and home care follow-up. Overall, the evidence for follow-up care for patients with long COVID-19 is limited

Towards a Better Understanding of the Relationship between Probabilistic Models in IR

Probability of relevance (PR) models are generally assumed to implement the Probability Ranking Principle (PRP) of IR, and recent publications claim that PR models and language models are similar. However, a careful analysis reveals two gaps in the chain of reasoning behind this statement. First, the PRP considers the relevance of particular documents, whereas PR models consider the relevance of any query-document pair. Second, unlike PR models, language models consider draws of terms and documents. We bridge the first gap by showing how the probability measure of PR models can be used to define the probabilistic model of the PRP. Furthermore, we argue that given the differences between PR models and language models, the second gap cannot be bridged at the probabilistic model level. We instead define a new PR model based on logistic regression, which has a similar score function to the one of the query likelihood model. The performance of both models is strongly correlated, hence providing a bridge for the second gap at the functional and ranking level. Understanding language models in relation with logistic regression models opens ample new research directions which we propose as future work

Influência do tempo de difusão de boro no campo retrodifusor seletivo de alumínio e boro em células solares de silício

O campo retrodifusor seletivo em células solares possibilita aumentar a eficiência e evita o abaulamento. O objetivo deste trabalho é analisar a influência do tempo de difusão de boro na formação do campo retrodifusor seletivo de alumínio e boro em células solares processadas em lâminas de silício Czochralski tipo p, grau solar. A difusão de boro foi implementada em toda a face posterior da lâmina e por serigrafia foi depositada a pasta de alumínio, somente nas trilhas metálicas. O processo de queima das pastas metálicas foi realizado em forno de esteira. Variou-se o tempo de difusão de boro de 10 a 30 minutos para a temperatura de difusão de 950 a 970 °C. Constatou-se que o melhor tempo de difusão depende da temperatura de difusão de boro e que a maior eficiência média, de (15,6 ± 0,1) %, foi obtida para a temperatura de 970 °C e tempo de difusão de 30 minutos.The selective back surface field in solar cells enables to increase the efficiency and avoid the bowing. The objective of this study is to analyze the influence of boron diffusion time in the formation of boron/aluminum selective back surface field. The solar cells were processed in solar grade Si-Cz wafers. The boron diffusion was performed in the whole rear face of the silicon wafer and the aluminum paste was deposited by screen printing, only in the metal fingers. The firing process of the metal pastes was performed in a belt furnace. The boron diffusion time was ranged from 10 to 30 minutes for the diffusion temperature from 950 °C to 970 °C. It was found that the better diffusion time depends on the boron diffusion temperature and the highest average efficiency of solar cells, of (15.6 ± 0.1) %, was obtained with the temperature of 970 °C and the diffusion time of 30 minutes.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism

Análise de processos de oxidação com Trans-LC para fabricação de células solares

Apesar do filme para passivação padrão da indústria de células solares atual ser SiNx, as últimas tendências do mercado fazem com que seja necessário reavaliar o SiO2 para passivação das superfícies de células solares. Para crescer estes óxidos, no entanto, são necessárias etapas de processamento em altas temperaturas, que deixam as lâminas de silício suscetíveis a contaminações metálicas. Para evitar essa contaminação, o composto orgânico Trans-LC é utilizado para limpeza do tubo de oxidação. O objetivo deste trabalho é avaliar a eficácia deste composto para limpeza dos tubos e determinar a qualidade da passivação que os óxidos produzidos desta forma proporcionam para as lâminas de Si. Observou-se que as limpezas realizadas não foram capazes de prevenir a contaminação de lâminas de Si de alto tempo de vida inicial. Porém, o Trans-LC foi suficientemente eficaz para oxidações realizadas em lâminas de baixo tempo de vida dos portadores minoritários.Even though the standard film for passivation currently utilized in the silicon solar cell industry is SiNx, the late tendencies of the market make it necessary to reevaluate the SiO2 for surface passivation of solar cells. In order to grow these oxides, however, high-temperature processing steps are necessary, which leave the wafers susceptible to metallic contamination. To avoid this contamination, the organic compound Trans-LC is used to clean the oxidation tube. The goal of this work is to evaluate the efficacy of this compound for the tube cleaning and determine the passivation quality that the oxides produced this way provide to the Si wafers. It was observed that the cleanings were not capable to prevent the contamination of high initial lifetime Si wafers. However, the Trans-LC was sufficiently effective for oxidations realized on wafers with low initial minority carrier lifetime.Tema 4: Energía solar, conversión fotovoltaica.Facultad de Arquitectura y Urbanism