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Optimum size in grid soil sampling for variable rate application in site-specific management; Tamanho ideal em grades de amostragem de solos para aplicação em taxa variável em manejo localizado

NANNI, Marcos Rafael; POVH, Fabrício Pinheiro; DEMATTÊ, José Alexandre Melo; OLIVEIRA, Roney Berti de; CHICATI, Marcelo Luiz; CEZAR, Everson
Fonte: São Paulo - Escola Superior de Agricultura Luiz de Queiroz Publicador: São Paulo - Escola Superior de Agricultura Luiz de Queiroz
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.5%
The importance of understanding spatial variability of soils is connected to crop management planning. This understanding makes it possible to treat soil not as a uniform, but a variable entity, and it enables site-specific management to increase production efficiency, which is the target of precision agriculture. Questions remain as the optimum soil sampling interval needed to make site-specific fertilizer recommendations in Brazil. The objectives of this study were: i) to evaluate the spatial variability of the main attributes that influence fertilization recommendations, using georeferenced soil samples arranged in grid patterns of different resolutions; ii) to compare the spatial maps generated with those obtained with the standard sampling of 1 sample ha-1, in order to verify the appropriateness of the spatial resolution. The attributes evaluated were phosphorus (P), potassium (K), organic matter (OM), base saturation (V%) and clay. Soil samples were collected in a 100 × 100 m georeferenced grid. Thinning was performed in order to create a grid with one sample every 2.07, 2.88, 3.75 and 7.20 ha. Geostatistical techniques, such as semivariogram and interpolation using kriging, were used to analyze the attributes at the different grid resolutions. This analysis was performed with the Vesper software package. The maps created by this method were compared using the kappa statistics. Additionally...

Variabilidade espacial de atributos de um solo sob videira em Vitória Brasil (SP)

Carvalho, M. P.; Takeda, E. Y.; Freddi, O. S.
Fonte: Sociedade Brasileira de Ciência do Solo Publicador: Sociedade Brasileira de Ciência do Solo
Tipo: Artigo de Revista Científica Formato: 695-703
Português
Relevância na Pesquisa
35.97%
Foi pesquisada a variabilidade espacial de alguns atributos físicos e químicos de uma associação de solos cultivada sob videira (Vitis vinifera-L), do município de Vitória Brasil, estado de São Paulo, Brasil. O objetivo foi estudar a dependência espacial de tais atributos, assim como caracterizar as respectivas variabilidades, distribuições de freqüência e números mínimos de subamostras do solo para a cultura da videira. Para isso, coletaram-se dados do solo, dispostos segundo uma malha com 156 pontos amostrais, sendo analisados por meio da geoestatística. As maiores variabilidades foram verificadas para a macroporosidade (MA), P, K, Ca, Mg, SB e CTC, ao passo que as menores foram para a densidade do solo (DS), pH e V. O número mínimo de subamostras, necessário para formar uma amostra composta e representativa, variou de 1 (pH e V) a 241 (Mg), tendo seu valor médio de 64 subamostras. Quanto à dependência espacial, o P e o V apresentaram, respectivamente, forte e fraca dependência, enquanto o restante dos atributos apresentou moderada dependência. Desta forma, o alcance dos atributos físicos variou de 2,56 a 4,32 m, enquanto o dos químicos variou de 1,82 a 5,64 m.; The spatial variability of some physical and chemical characteristics of a compound of soils under grapevine (Vitis vinifera-L) cultivation was studied in the county Vitória Brasil...

Grid data mining by means of learning classifier systems and distributed model induction

Santos, Manuel Filipe; Mathew, Wesley; Santos, Henrique Dinis dos
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em //2011 Português
Relevância na Pesquisa
36.09%
This paper introduces a distributed data mining approach suited to grid computing environments based on a supervised learning classifier system. Different methods of merging data mining models generated at different distributed sites are explored. Centralized Data Mining (CDM) is a conventional method of data mining in distributed data. In CDM, data that is stored in distributed locations have to be collected and stored in a central repository before executing the data mining algorithm. CDM method is reliable; however it is expensive (computational, communicational and implementation costs are high). Alternatively, Distributed Data Mining (DDM) approach is economical but it has limitations in combining local models. In DDM, the data mining algorithm has to be executed at each one of the sites to induce a local model. Those induced local models are collected and combined to form a global data mining model. In this work six different tactics are used for constructing the global model in DDM: Generalized Classifier Method (GCM); Specific Classifier Method (SCM); Weighed Classifier Method (WCM); Majority Voting Method (MVM); Model Sampling Method (MSM); and Centralized Training Method (CTM). Preliminary experimental tests were conducted with two synthetic data sets (eleven multiplexer and monks3) and a real world data set (intensive care medicine). The initial results demonstrate that the performance of DDM methods is competitive when compared with the CDM methods.; Fundação para a Ciência e a Tecnologia (FCT)

Grid data mining strategies for outcome prediction in distributed intensive care units

Santos, Manuel Filipe; Portela, Filipe; Miranda, Miguel; Machado, José Manuel; Abelha, António; Silva, Álvaro; Rua, Fernando
Fonte: Springer Publicador: Springer
Tipo: Parte de Livro
Publicado em //2012 Português
Relevância na Pesquisa
36.09%
Previous work developed to predict the outcome of patients in the context of intensive care units brought to the light some requirements like the need to deal with distributed data sources. Those data sources can be used to induce local prediction models and those models can in turn be used to induce global models more accurate and more general than the local models. This paper introduces a distributed data mining approach suited to grid computing environments based on a supervised learning classifier system. Five different tactics are explored for constructing the global model in a Distributed Data Mining (DDM) approach: Generalized Classifier Method (GCM); Specific Classifier Method (SCM); Weighed Classifier Method (WCM); Majority Voting Method (MVM); and Model Sampling Method (MSM). Experimental tests were conducted with a real world data set from the intensive care medicine. The results demonstrate that the performance of DDM methods is very competitive when compared with the centralized methods.; Fundação para a Ciência e a Tecnologia (FCT)

Towards a universal sampling protocol for soil biotas in the humid tropics

Bignell,David Edward
Fonte: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira Publicador: Embrapa Informação Tecnológica; Pesquisa Agropecuária Brasileira
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2009 Português
Relevância na Pesquisa
36.16%
This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized) loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help sustain agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB) to the final schemes (with variants) adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD). Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust...

Optimum size in grid soil sampling for variable rate application in site-specific management

Nanni,Marcos Rafael; Povh,Fabrício Pinheiro; Demattê,José Alexandre Melo; Oliveira,Roney Berti de; Chicati,Marcelo Luiz; Cezar,Everson
Fonte: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz" Publicador: São Paulo - Escola Superior de Agricultura "Luiz de Queiroz"
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2011 Português
Relevância na Pesquisa
46.5%
The importance of understanding spatial variability of soils is connected to crop management planning. This understanding makes it possible to treat soil not as a uniform, but a variable entity, and it enables site-specific management to increase production efficiency, which is the target of precision agriculture. Questions remain as the optimum soil sampling interval needed to make site-specific fertilizer recommendations in Brazil. The objectives of this study were: i) to evaluate the spatial variability of the main attributes that influence fertilization recommendations, using georeferenced soil samples arranged in grid patterns of different resolutions; ii) to compare the spatial maps generated with those obtained with the standard sampling of 1 sample ha-1, in order to verify the appropriateness of the spatial resolution. The attributes evaluated were phosphorus (P), potassium (K), organic matter (OM), base saturation (V%) and clay. Soil samples were collected in a 100 × 100 m georeferenced grid. Thinning was performed in order to create a grid with one sample every 2.07, 2.88, 3.75 and 7.20 ha. Geostatistical techniques, such as semivariogram and interpolation using kriging, were used to analyze the attributes at the different grid resolutions. This analysis was performed with the Vesper software package. The maps created by this method were compared using the kappa statistics. Additionally...

Towards an optimal sampling strategy for assessing genetic variation within and among white clover (Trifolium repens L.) cultivars using AFLP

Khanlou,Khosro Mehdi; Vandepitte,Katrien; Asl,Leila Kheibarshekan; Bockstaele,Erik Van
Fonte: Sociedade Brasileira de Genética Publicador: Sociedade Brasileira de Genética
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2011 Português
Relevância na Pesquisa
36.16%
Cost reduction in plant breeding and conservation programs depends largely on correctly defining the minimal sample size required for the trustworthy assessment of intra- and inter-cultivar genetic variation. White clover, an important pasture legume, was chosen for studying this aspect. In clonal plants, such as the aforementioned, an appropriate sampling scheme eliminates the redundant analysis of identical genotypes. The aim was to define an optimal sampling strategy, i.e., the minimum sample size and appropriate sampling scheme for white clover cultivars, by using AFLP data (283 loci) from three popular types. A grid-based sampling scheme, with an interplant distance of at least 40 cm, was sufficient to avoid any excess in replicates. Simulations revealed that the number of samples substantially influenced genetic diversity parameters. When using less than 15 per cultivar, the expected heterozygosity (He) and Shannon diversity index (I) were greatly underestimated, whereas with 20, more than 95% of total intra-cultivar genetic variation was covered. Based on AMOVA, a 20-cultivar sample was apparently sufficient to accurately quantify individual genetic structuring. The recommended sampling strategy facilitates the efficient characterization of diversity in white clover...

Precision agriculture for sugarcane management: a strategy applied for brazilian conditions

Demattê,José Alexandre Melo; Demattê,José Luiz Ioratte; Alves,Evandro Roberto; Negrão,Roberto; Morelli,Jorge Luis
Fonte: Editora da Universidade Estadual de Maringá - EDUEM Publicador: Editora da Universidade Estadual de Maringá - EDUEM
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/03/2014 Português
Relevância na Pesquisa
36.22%
The region of Areiópolis in São Paulo State is one of the major sugarcane producers in the world, and chemical management is the basis of the system making its production viable. Thus, the proposed methods for precision agriculture can be evaluated as an alternative for environment protection and can aid the search for greater productivity at the same time. The main objective of the present work was to compare the precision agriculture (PA) and traditional agriculture (TA) management systems and to highlight their distinctions, such as differences in grid sampling, production variation, plant failure and costs. Two experiments were set up, and the soil fertilizers were applied by corrective application methods to 16-ha lots using the average general fertility rate (GFR). The PA method had the highest productivity volume for conversion of green matter to sugar in the 4.0-ha plots. As the size of the PA plots decreased, the costs of soil analyses increased with potassium and lime analyses being the most expensive. The PA plots had more suitable grid sampling in terms of productivity, and the cost/benefit ratio was 4.0-ha. In general, the final cost was higher in the PA system compared to the TA system. The present results provide information to help select the better system between these techniques to manage tropical soils.

Sampling designs matching species biology produce accurate and affordable abundance indices

Harris, Grant; Farley, Sean; Russell, Gareth J.; Butler, Matthew J.; Selinger, Jeff
Fonte: PeerJ Inc. Publicador: PeerJ Inc.
Tipo: Artigo de Revista Científica
Publicado em 17/12/2013 Português
Relevância na Pesquisa
36.63%
Wildlife biologists often use grid-based designs to sample animals and generate abundance estimates. Although sampling in grids is theoretically sound, in application, the method can be logistically difficult and expensive when sampling elusive species inhabiting extensive areas. These factors make it challenging to sample animals and meet the statistical assumption of all individuals having an equal probability of capture. Violating this assumption biases results. Does an alternative exist? Perhaps by sampling only where resources attract animals (i.e., targeted sampling), it would provide accurate abundance estimates more efficiently and affordably. However, biases from this approach would also arise if individuals have an unequal probability of capture, especially if some failed to visit the sampling area. Since most biological programs are resource limited, and acquiring abundance data drives many conservation and management applications, it becomes imperative to identify economical and informative sampling designs. Therefore, we evaluated abundance estimates generated from grid and targeted sampling designs using simulations based on geographic positioning system (GPS) data from 42 Alaskan brown bears (Ursus arctos). Migratory salmon drew brown bears from the wider landscape...

New Insights into the Developing Rabbit Brain Using Diffusion Tensor Tractography and Generalized q-Sampling MRI

Lim, Seong Yong; Tyan, Yeu-Sheng; Chao, Yi-Ping; Nien, Fang-Yu; Weng, Jun-Cheng
Fonte: Public Library of Science Publicador: Public Library of Science
Tipo: Artigo de Revista Científica
Publicado em 23/03/2015 Português
Relevância na Pesquisa
36.05%
The use of modern neuroimaging methods to characterize the complex anatomy of brain development at different stages reveals an enormous wealth of information in understanding this highly ordered process and provides clues to detect neurological and neurobehavioral disorders that have their origin in early structural and functional cerebral maturation. Non-invasive diffusion tensor magnetic resonance imaging (DTI) is able to distinguish cerebral microscopic structures, especially in the white matter regions. However, DTI is unable to resolve the complicated neural structure, i.e., the fiber crossing that is frequently observed during the maturation process. To overcome this limitation, several methods have been proposed. One such method, generalized q-sampling imaging (GQI), can be applied to a variety of datasets, including the single shell, multi-shell or grid sampling schemes that are believed to be able to resolve the complicated crossing fibers. Rabbits have been widely used for neurodevelopment research because they exhibit human-like timing of perinatal brain white matter maturation. Here, we present a longitudinal study using both DTI and GQI to demonstrate the changes in cerebral maturation of in vivo developing rabbit brains over a period of 40 weeks. Fractional anisotropy (FA) of DTI and generalized fractional anisotropy (GFA) of GQI indices demonstrated that the white matter anisotropy increased with age...

Towards a universal sampling protocol for soil biotas in the humid tropics.

BIGNELL D. E.
Fonte: Pesquisa Agropecuária Brasileira, Brasília, DF, v. 44, n. 8, p.825-834, ago. 2009. Publicador: Pesquisa Agropecuária Brasileira, Brasília, DF, v. 44, n. 8, p.825-834, ago. 2009.
Tipo: Artigo em periódico indexado (ALICE)
Português
Relevância na Pesquisa
36.16%
This paper reviews the methods for the inventory of below-ground biotas in the humid tropics, to document the (hypothesized) loss of soil biodiversity associated with deforestation and agricultural intensification at forest margins. The biotas were grouped into eight categories, each of which corresponded to a major functional group considered important or essential to soil function. An accurate inventory of soil organisms can assist in ecosystem management and help sustain agricultural production. The advantages and disadvantages of transect-based and grid-based sampling methods are discussed, illustrated by published protocols ranging from the original "TSBF transect", through versions developed for the alternatives to Slash-and-Burn Project (ASB) to the final schemes (with variants) adopted by the Conservation and Sustainable Management of Below-ground Biodiversity Project (CSM-BGBD). Consideration is given to the place and importance of replication in below-ground biological sampling and it is argued that the new sampling protocols are inclusive, i.e. designed to sample all eight biotic groups in the same field exercise; spatially scaled, i.e. provide biodiversity data at site, locality, landscape and regional levels, and link the data to land use and land cover; and statistically robust...

Evaluation of dead beat current controllers for grid connected converters

Wang, L.; Ertugrul, N.; Kolhe, M.
Fonte: IEEE; USA Publicador: IEEE; USA
Tipo: Conference paper
Publicado em //2012 Português
Relevância na Pesquisa
36.31%
The voltage source converters (VSCs) are widely preferred topologies for grid connection of renewable energy systems. This paper aims to evaluate the various types of deadbeat (DB) current controllers for the VSCs, which offer fast and finite settling time. The type of DB current controllers discussed in this paper aims to achieve the current command in one and two sampling time delay. Two compensation methods for one sampling time delay of DB control are the reducing the proportional gain method and Smith Predictor method. In the two sampling time delay of DB current controllers, two different implementation schemes are designed, which are based on the development of an internal model control through the feedback transfer function. In this paper four types of controllers are investigated in detail in terms of control algorithm design, system stability analysis and sensitivity analysis of plant parameter variations. In addition, PSCAD based computer simulation studies are presented in the paper to evaluate the performance of each controllers.; Liying Wang, Nesimi Ertugrul and Mohan Kolhe

Determinação de tamanhos de parcelas para otimização amostral em remanescentes de florestas nativas em Itatinga-SP; Determination of plot size for optimization of sampling in remnant natural forests in Itatinga - SP

Goffe, Renan Fischer
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 28/08/2015 Português
Relevância na Pesquisa
36.19%
Devido a atual situação de degradação da vegetação remanescente do estado de São Paulo, existe com relativa urgência uma grande necessidade de estudos que apoiem práticas de monitoramento e conservação dos fragmentos florestais para melhor gerenciá-los. Parte destas demandas é referente ao campo de amostragem, um conjunto de técnicas específicas para pesquisas ecológicas, onde a unidade amostral (parcela) é um dos fatores determinantes de sua eficiência. O objetivo deste estudo foi definir e propor o tamanho ideal de parcelas para otimizar o inventário florestal de áreas remanescentes de Floresta Estacional Semidecidual (FES) e de Cerrado (CER), assim como também de Floresta Estacional Semidecidual em processo de regeneração (FESreg). O trabalho foi realizado na Estação Experimental de Ciências Florestais de Itatinga - SP (EECFI/ESALQ/USP), visando à otimização da amostragem para as variáveis diâmetro à altura do peito (DAP), altura total, densidade populacional, área basal, volume total, volume de fuste, volume de galho, biomassa e índices de Shannon, de Simpson e de Riqueza. O delineamento experimental foi realizado com o auxílio de uma grade amostral, na qual foram distribuídas aleatoriamente 15 parcelas de 1.000 m2 cada...

Non-optimality of rank-1 lattice sampling in spaces of hybrid mixed smoothness

Byrenheid, Glenn; Kämmerer, Lutz; Ullrich, Tino; Volkmer, Toni
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 28/10/2015 Português
Relevância na Pesquisa
36.09%
We consider the approximation of functions with hybrid mixed smoothness based on rank-1 lattice sampling. We prove upper and lower bounds for the sampling rates with respect to the number of lattice points in various situations and achieve improvements in the main error rate compared to earlier contributions to the subject. This main rate (without logarithmic factors) is half the optimal main rate coming for instance from sparse grid sampling and turns out to be best possible among all algorithms taking samples on lattices.

Computational Realization of a Non-Equidistant Grid Sampling in Photoacoustics with a Non-Uniform FFT

Schmid, Julian; Glatz, Thomas; Zabihian, Behrooz; Liu, Mengyang; Drexler, Wolfgang; Scherzer, Otmar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 13/01/2015 Português
Relevância na Pesquisa
36.05%
To obtain the initial pressure from the collected data on a planar sensor arrangement in Photoacoustic tomography, there exists an exact analytic frequency domain reconstruction formula. An efficient realization of this formula needs to cope with the evaluation of the datas Fourier transform on a non-equispaced mesh. In this paper, we use the non-uniform fast Fourier transform to handle this issue and show its feasibility in 3D experiments. This is done in comparison to the standard approach that uses polynomial interpolation. Moreover, we investigate the effect and the utility of flexible sensor location on the quality of photoacoustic image reconstruction. The computational realization is accomplished by the use of a multi-dimensional non-uniform fast Fourier algorithm, where non-uniform data sampling is performed both in frequency and spatial domain. We show that with appropriate sampling the imaging quality can be significantly improved. Reconstructions with synthetic and real data show the superiority of this method.

Non-Equispaced Grid Sampling in Photoacoustics with a Non-Uniform FFT

Schmid, Julian; Glatz, Thomas; Zabihian, Behrooz; Liu, Mengyang; Drexler, Wolfgang; Scherzer, Otmar
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 05/10/2015 Português
Relevância na Pesquisa
35.97%
To obtain the initial pressure from the collected data on a planar sensor arrangement in photoacoustic tomography, there exists an exact analytic frequency domain reconstruction formula. An efficient realization of this formula needs to cope with the evaluation of the data's Fourier transform on a non-equispaced mesh. In this paper, we use the non-uniform fast Fourier transform to handle this issue and show its feasibility in 3D experiments with real and synthetic data. This is done in comparison to the standard approach that uses linear, polynomial or nearest neighbor interpolation. Moreover, we investigate the effect and the utility of flexible sensor location to make optimal use of a limited number of sensor points. The computational realization is accomplished by the use of a multi-dimensional non-uniform fast Fourier algorithm, where non-uniform data sampling is performed both in frequency and spatial domain. Examples with synthetic and real data show that both approaches improve image quality.; Comment: arXiv admin note: substantial text overlap with arXiv:1501.02946

Tamanho ideal em grades de amostragem de solos para aplicação em taxa variável em manejo localizado; Optimum size in grid soil sampling for variable rate application in site-specific management

Nanni, Marcos Rafael; Povh, Fabrício Pinheiro; Demattê, José Alexandre Melo; Oliveira, Roney Berti de; Chicati, Marcelo Luiz; Cezar, Everson
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/06/2011 Português
Relevância na Pesquisa
46.5%
A importância de compreender a variabilidade espacial do solo está conectada ao planejamento do manejo das culturas. Este entendimento faz com que seja possível tratar o solo não como uma entidade uniforme, mas variável, e permite o gerenciamento de sítios específicos para aumentar a eficiência de produção, que é o objetivo da agricultura de precisão. Questões relacionadas com a otimização do intervalo de amostragem do solo se faz necessário para a realização das recomendações de adubações no Brasil. Os objetivos deste estudo foram: i) avaliar a variabilidade espacial dos principais atributos que influenciam as recomendações de adubação, usando amostras de solos georreferenciadas dispostas em padrões de grades de diferentes resoluções; ii) comparar os mapas espaciais gerados com o mapa padrão obtido com amostragem de 1 amostra ha-1, a fim de verificar a adequação da resolução espacial. Os atributos avaliados foram fósforo (P), potássio (K), matéria orgânica (MO), saturação por bases (V%) e argila. As amostras de solos foram coletadas numa grade de 100 × 100 m e georreferenciadas. Um desbaste foi realizado, criando-se uma grade com 1 amostra a cada 2,07, 2,88, 3,75 e 7,20 ha. Técnicas de geoestatística...

SAMPLING DENSITY INTERFERENCE ON SOIL FEATURE SPATIALIZATION BY MAPPING CAMBISOL UNIT TAXONOMY; INTERFERÊNCIA DA DENSIDADE DE AMOSTRAGEM NA ESPACIALIZAÇÃO DOS ATRIBUTOS DO SOLO PARA FINS DE MAPEAMENTO DAS UNIDADES TAXONÔMICAS CAMBISSOLO

SOUZA, Luiz Claudio de Paula; Universidade Federal do Paraná (UFPR), Curitiba- PR; OLIVEIRA JUNIOR, Jairo Calderari de; Universidade Federal do Paraná (UFPR), Curitiba- PR
Fonte: UFPR Publicador: UFPR
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Formato: application/pdf
Publicado em 24/05/2010 Português
Relevância na Pesquisa
36.23%
In an area that have approximately 10 ha the B horizon were sampled on a regular grid with 133 points 30 m distant to each other (30x30) and another with 77 points 60 m distant to each other (60x60). Texture, exchangeable Ca+2, Mg+2, K+, H+, Al+3, H + Al, organic carbon were determined. The classic statistic and geoestatistics analyses were used to identify the variability structure, taking a model for further interpolation. These attributes were interpolated by kriging method, then applied the map algebra and Boolean analysis for identify the diagnostic horizon as well the others taxonomy classes until the specific level group.It was possible to identify by semivariogram analysis that values of proportion, nugget, range, r2 and RSS were near each other in the both grids, with the exception of H + Al.In application of taxonomy discretion, the CXa and CXvd units were not identified in the reduced grid.  Even though the CXbd was identified in both grids, it was different in the spatial distribution and expression of area.; Em uma área de aproximadamente 10 ha foram coletadas amostras do horizonte B em uma grade regular com espaçamento de 30x30 m e 60x60 m, totalizando 133 pontos e 77 pontos amostrados respectivamente. Após análises laboratoriais de textura...

Designing an advanced RC drilling grid for short-term planning in open pit mines: three case studies

Ortiz,J.M.; Magri,E.J.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2014 Português
Relevância na Pesquisa
36.29%
SYNOPSIS This paper shows the usefulness of geostatistical conditional simulation combined with the quantification of sampling errors obtained from the analyses of fundamental errors - validated from duplicate data - to assess the relevance of the quality and quantity of the information, for short-term mine planning purposes. Traditional blast-hole drilling equipment has been designed for efficient drilling, but not for obtaining high-quality samples. Furthermore, blast-hole sampling interferes with production, and thus usually produces poor-quality results. These results are the basis of short-term plans, where the grades of selective mining units are estimated and used for distinguishing between ore and waste. Under these conditions, misclassification (ore blocks sent to the waste dump and waste blocks processed at the plant) is inevitable, leading to significant hidden losses that can amount to millions of dollars per annum. Reverse circulation drilling with the latest automated sampling technology improves significantly the quality of the information used for short-term planning, and thus reduces misclassification, improving the financial returns of the operation. In this paper, we present the general methodology for assessing the effect of poor blast-hole sampling...

Transferring sampling errors into geostatistical modelling

Cuba,M.; Leuangthong,O.; Ortiz,J.
Fonte: Journal of the Southern African Institute of Mining and Metallurgy Publicador: Journal of the Southern African Institute of Mining and Metallurgy
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2012 Português
Relevância na Pesquisa
36.09%
Geostatistical modelling aims at providing unbiased estimates of the grades of elements of economic interest in mining operations, and assessing the associated uncertainty in these resources and reserves. Conventional practice consists of using the data as error-free values and performing the typical steps of data analysis -domaining, semivariogram analysis, and estimation/simulation. However, in many mature deposits, information comes from different drilling campaigns that were sometimes completed decades ago, when little or no quality assurance and quality control (QA/QC) procedures were available. Although this legacy data may have significant sampling errors, it provides valuable information and should be combined with more recent data that has been subject to strict QA/QC procedures. In this paper we show that ignoring the errors associated with sample data considerably underestimates the uncertainty (and consequently the economic risk) associated with a mining project. We also provide a methodology to combine data with different sampling errors, thus preserving the relevant global and local statistics. The method consists of constructing consistent simulated sets of values at the sample locations, in order to reproduce the error of each drilling campaign and the spatial correlation of the grades. It is based on a Gibbs sampler...