Dissertations / Theses on the topic 'Kriging and cokriging models'
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Adu, Agyemang Adela Beauty. "Vulnerability Assessment of Groundwater to NO3 Contamination Using GIS, DRASTIC Model and Geostatistical Analysis." Digital Commons @ East Tennessee State University, 2017. https://dc.etsu.edu/etd/3264.
Full textYATES, SCOTT RAYMOND. "GEOSTATISTICAL METHODS FOR ESTIMATING SOIL PROPERTIES (KRIGING, COKRIGING, DISJUNCTIVE)." Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/187990.
Full textLong, Andrew Edmund. "Cokriging, kernels, and the SVD: Toward better geostatistical analysis." Diss., The University of Arizona, 1994. http://hdl.handle.net/10150/186892.
Full textJohnson, Crystal. "Using Kriging, Cokriging, and GIS to Visualize Fe and Mn in Groundwater." Digital Commons @ East Tennessee State University, 2015. https://dc.etsu.edu/etd/2498.
Full textHemmati, Sahar. "Steady-State Co-Kriging Models." Thesis, West Virginia University, 2017. http://pqdtopen.proquest.com/#viewpdf?dispub=10614907.
Full textIn deterministic computer experiments, a computer code can often be run at different levels of complexity/fidelity and a hierarchy of levels of code can be obtained. The higher the fidelity and hence the computational cost, the more accurate output data can be obtained. Methods based on the co-kriging methodology Cressie (2015) for predicting the output of a high-fidelity computer code by combining data generated to varying levels of fidelity have become popular over the last two decades. For instance, Kennedy and O’Hagan (2000) first propose to build a metamodel for multi-level computer codes by using an auto-regressive model structure. Forrester et al. (2007) provide details on estimation of the model parameters and further investigate the use of co-kriging for multi-fidelity optimization based on the efficient global optimization algorithm Jones et al. (1998). Qian and Wu (2008) propose a Bayesian hierarchical modeling approach for combining low-accuracy and high-accuracy experiments. More recently, Gratiet and Cannamela (2015) propose sequential design strategies using fast cross-validation techniques for multi-fidelity computer codes.
This research intends to extend the co-kriging metamodeling methodology to study steady-state simulation experiments. First, the mathematical structure of co-kriging is extended to take into account heterogeneous simulation output variances. Next, efficient steady-state simulation experimental designs are investigated for co-kriging to achieve a high prediction accuracy for estimation of steady-state parameters. Specifically, designs consisting of replicated longer simulation runs at a few design points and replicated shorter simulation runs at a larger set of design points will be considered. Also, design with no replicated simulation runs at long simulation is studied, along with different methods for calculating the output variance in absence of replicated outputs.
Stochastic co-kriging (SCK) method is applied to an M/M/1, as well as an M/M/5 queueing system. In both examples, the prediction performance of the SCK model is promising. It is also shown that the SCK method provides better response surfaces compared to the SK method.
Watanabe, Jorge. "Métodos geoestatísticos de co-estimativas: estudo do efeito da correlação entre variáveis na precisão dos resultados." Universidade de São Paulo, 2008. http://www.teses.usp.br/teses/disponiveis/44/44137/tde-14082008-165227/.
Full textThis master dissertation presents the results of a survey into co-estimation methods commonly used in geostatistics. These methods are ordinary cokriging, collocated cokriging and kriging with an external drift. Besides that ordinary kriging was considered just to illustrate how it does work when the primary variable is poorly sampled. As we know co-estimation methods depend on a secondary variable sampled over the estimation domain. Moreover, this secondary variable should present linear correlation with the main variable or primary variable. Usually the primary variable is poorly sampled whereas the secondary variable is known over the estimation domain. For instance in oil exploration the primary variable is porosity as measured on rock samples gathered from drill holes and the secondary variable is seismic amplitude derived from processing seismic reflection data. It is important to mention that primary and secondary variables must present some degree of correlation. However, we do not know how they work depending on the correlation coefficient. That is the question. Thus, we have tested co-estimation methods for several data sets presenting different degrees of correlation. Actually, these data sets were generated in computer based on some data transform algorithms. Five correlation values have been considered in this study: 0.993; 0.870; 0.752; 0.588 and 0.461. Collocated simple cokriging was the best method among all tested. This method has an internal filter applied to compute the weight for the secondary variable, which in its turn depends on the correlation coefficient. In fact, the greater the correlation coefficient the greater the weight of secondary variable is. Then it means this method works even when the correlation coefficient between primary and secondary variables is low. This is the most impressive result that came out from this research.
Araújo, Cristina da Paixão. "Uso de informação secundária imprecisa e inacurada no planejamento de curto prazo." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/127891.
Full textDecisions starting at mineral exploration through mining are based on grade block models obtained from samples. To decrease the uncertainty in the estimates, the short term mining planning requires additional sampling to ensure accurate and precise predictions. As more samples are made available, there is trend towards more reliable estimates. In the exploration stage, usually, sampling is performed by diamond drill holes (DDH), which are expensive but produces accurate and precise samples. In this stage there are few data with high quality. In the production stage, sampling is obtained by other techniques due to the high costs of DDHs. In general, these samples have low quality and are not controlled by QA / QC protocols. This study evaluates the impact of using imprecise data in short-term mineplanning. For this, it was analyzed two different data sets. The first case used the exhaustive Walker Lake dataset as the source to obtain the true and sampled grades. Initially, samples were obtained from the exhaustive dataset at regularly spaced grids at 20 × 20 m and 5 × 5 meters. A relative error (imprecision) of ± 25% and a 10% bias were added to the data spaced at 5 × 5 m (short-term geological data) in different scenarios. The second study is in a gold mine with two different types of data obtained from diamond drilling holes (DDH_Hard data) and reverse circulation (RC_Soft data).To combine these different types of data, two methodologies were investigated: cokriging and ordinary kriging. Both types of data were used to estimate a block model using the two methodologies. The grade tonnage curves and swath plots were used to compare the results against the true block grades at the same block support. In addition, the block misclassification was evaluated. In the Walker Lake the results show that standardized ordinary cokriging is a better methodology for imprecise and biased data and produces estimates closer to the true grade block distribution, reducing block misclassification. For the data set at the underground mine gold, the samples had moderate correlation and short spatial continuity for small distances at this deposit. In this situation, the estimates using ordinary kriging with hard and soft data (standardized and re-escaled) produced better results with less bias and better blocks classification of ore and waste.
Wang, Xiang. "Two kriging models, and the expanded readsold package." Ohio University / OhioLINK, 1986. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1183382153.
Full textMuré, Joseph. "Objective Bayesian analysis of Kriging models with anisotropic correlation kernel." Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC069/document.
Full textA recurring problem in surrogate modelling is the scarcity of available data which hinders efforts to estimate model parameters. The Bayesian paradigm offers an elegant way to circumvent the problem by describing knowledge of the parameters by a posterior probability distribution instead of a pointwise estimate. However, it involves defining a prior distribution on the parameter. In the absence of expert opinion, finding an adequate prior can be a trying exercise. The Objective Bayesian school proposes default priors for such can be a trying exercise. The Objective Bayesian school proposes default priors for such situations, like the Berger-Bernardo reference prior. Such a prior was derived by Berger, De Oliveira and Sansó [2001] for the Kriging surrogate model with isotropic covariance kernel. Directly extending it to anisotropic kernels poses theoretical as well as practical problems because the reference prior framework requires ordering the parameters. Any ordering would in this case be arbitrary. Instead, we propose an Objective Bayesian solution for Kriging models with anisotropic covariance kernels based on conditional reference posterior distributions. This solution is made possible by a theory of compromise between incompatible conditional distributions. The work is then shown to be compatible with Trans-Gaussian Kriging. It is applied to an industrial case with nonstationary data in order to derive Probability Of defect Detection (POD) by non-destructive tests in steam generator tubes of nuclear power plants
Asritha, Kotha Sri Lakshmi Kamakshi. "Comparing Random forest and Kriging Methods for Surrogate Modeling." Thesis, Blekinge Tekniska Högskola, Fakulteten för datavetenskaper, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-20230.
Full textSilva, Abel Brasil Ramos da. "Estimation of curves indifference accessibility via urban models and ordered kriging." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10042.
Full textO processo de urbanizaÃÃo, crescimento das cidades e estruturaÃÃo urbana ocorrido nas Ãltimas dÃcadas nas grandes cidades brasileiras vem colocando a questÃo da acessibilidade como fator relevante na qualidade de vida da populaÃÃo. Neste contexto, analisar rigorosamente o nÃvel de acessibilidade e o bem-estar dos indivÃduos a partir do momento que deixam suas residÃncias atà o ponto de execuÃÃo de atividades ou satisfaÃÃo de consumo torna-se uma questÃo de grande importÃncia cientÃfica ainda pouco explorada de maneira rigorosa. Nesta dissertaÃÃo buscamos analisar e modelar acessibilidade considerando uma perspectiva teÃrica baseada na metodologia da maximizaÃÃo da utilidade e na estimaÃÃo de modelos economÃtricos. Para tanto, este estudo està dividindo em dois eixos de pesquisa: o primeiro, analisa a acessibilidade com o uso de modelos ordenados generalizados atravÃs de uma base inÃdita de micro dados geo-referenciados coletada na cidade de Fortaleza, Brasil. Os resultados mostram que variÃveis como renda, posse de automÃveis, distÃncia, entre outras, sÃo importantes para explicar a acessibilidade dos indivÃduos. O segundo eixo de anÃlise propÃe e desenvolve, de maneira pioneira, uma superfÃcie de utilidade espacial atravÃs de tÃcnicas de krigagem. Os resultados mostram que a distÃncia entre o domicÃlio e o ponto de destino possui uma relaÃÃo bastante heterogÃnea com a acessibilidade, revelando um padrÃo espacial influenciado pela desigualdade econÃmica da cidade. Esse resultado coloca em dÃvida suposiÃÃes simplistas tradicionais que assumem uma relaÃÃo linear ou polinomial entre distÃncia e acessibilidade.
The process of urbanization, growth of cities and urban structuring in recent decades among large Brazilian cities revealed the issue of accessibility as a relevant factor in quality of life. In this sense, analyzing the level of accessibility and welfare of individuals from where they leave their homes up to the point of execution of activities or consumer satisfaction becomes a matter of great scientific importance, yet to be explored in rigorously way. Thus, in this dissertation we analyze and model urban accessibility considering a theoretical perspective based on the methodology of utility maximization and estimation of econometric models. Therefore, this study is divided into two lines of research. The first one analyzes the accessibility using generalized ordered models through a new geo-referenced micro data set collected in the city of Fortaleza, Brazil. Our results show that variables such as income, car ownership, distance, and others are important for explaining accessibility of individuals. The second line of inquiry proposes and develops, in a pioneering way, a surface of spatial utility by means of Kriging techniques. The results point to the fact that the distance between home and destination has a very heterogeneous relationship with accessibility, revealing a spatial pattern greatly influenced by the prevailing economic inequalities all over the city. This result puts into question simplistic traditional assumptions that assume a linear or polynomial relation between distance and accessibility.
Wang, Zeyu. "Reliability Analysis and Updating with Meta-models: An Adaptive Kriging-Based Approach." The Ohio State University, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=osu1574789534726544.
Full textBean, Brennan L. "Interval-Valued Kriging Models with Applications in Design Ground Snow Load Prediction." DigitalCommons@USU, 2019. https://digitalcommons.usu.edu/etd/7579.
Full textJohansson, Björn. "Statistical Methods for Mineral Models of Drill Cores." Thesis, KTH, Matematisk statistik, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-279848.
Full textI den moderna gruvindustrin har nya resurseffektiva och klimatbeständiga metoder ökat i efterfråga. Beställda projekt för att förbättra effektiviteten gällande den europeiska gruvdriften bidrar till denna effekt ytterligare. Orexplore AB:s röntgenteknologi för analys av borrkärnor är för närvarande involverad i två sådana projekt. Orexplore AB vill integrera geostatistik (spatial statistik) i sin analysprocess för att ytterligare vidga informationen från mineraldatan. Den geostatistiska metoden som implementeras här är ordinary kriging, som är en interpolationsmetod som, givet uppmätta data, skattar mellanliggande värden betingade av kovariansmodeller. Ordinary kriging tillåter skattning av mineralkoncentrationer på ett kontinuerligt nät i 1-D upp till 3-D. Mellanliggande värden skattas enligt en Gaussisk process-regressionslinje. Kovariansen modelleras genom att passa en modell till ett beräknat experimentellt variogram. Mineralkoncentrationer är tillgängliga längs borrkärnans mantelyta. Ordinary kriging implementeras för att sekventiellt skatta mineralkoncentrationer på kortare delar av borrkärnan, ett mineral i taget. Interpolering av mineralkoncentrationer utförs på datan betraktad i 1-D och 3-D. Valideringen utförs genom att utifrån de skattade koncentrationerna beräkna den motsvarande densiteten vid varje sektion som koncentrationer skattas på och jämföra varje sådant värde med uppmätta densiteter. Undersökning av modellen utförs genom subjektiv visuell utvärdering av interpolationslinjens passning av datan, dess mjukhet, tillsammans med variansen. Dessutom testas passformen genom korsvalidering med olika mätvärden som utvärderar varians- och skattningsfel för olika modeller. Slutsatsen från resultaten är att denna metod reproducerar de uppmätta koncentrationerna väl samtidigt som den presterar bra enligt de mätvärden som utvärderas, men överträffar ej de uppmätta koncentrationerna vid utvärdering mot de uppmätta densiteterna. Metoden var emellertid framgångsrik med att tillhandahålla information om mineralerna i borrkärnan genom att producera mineralkoncentrationer på ett kontinuerligt rutnät. Metoden producerade också mineralkoncentrationer i 3-D som reproducerade de uppmätta densiteterna väl. Slutsatsen dras att ordinary kriging, implementerad enligt den metod som beskrivs i denna rapport, effektivt skattar mineralkoncentrationer som kan användas för att få information om fördelningen av koncentrationer i det inre av borrkärnan.
Lloyd, Christopher David. "Non-stationary models for optimal sampling and mapping of terrain in Great Britain." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.323957.
Full textAsfaw, Zeytu Gashaw. "Inference and Prediction in Non-stationary Stochastic Models: Survival Analysis and Kriging Interpolation." Doctoral thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2014. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-25982.
Full textYin, Hong. "Kriging model approach to modeling study on relationship between molecular quantitative structures and chemical properties." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/598.
Full textArnoult, Guillaume. "Modélisation de la trajectoire d'un projectile gyrostabilisé muni d'un dispositif de contrôle." Thesis, université Paris-Saclay, 2020. http://www.theses.fr/2020UPAST068.
Full textThe intensification of urban combat encourages the industrials of terrestrial armament to develop new weapon systems equipped with trajectory modification devices. Deploying these devices during the projectile flight would allow reducing the scattering error in order to narrow the collateral damage. The challenge lies in the development of a device adapted to the flight conditions of a spin-stabilized projectile. An isolated spoiler, installed on a rotatable ring, is chosen as the most adapted control device. This work consists in developing an optimization algorithm for the geometrical parameters of the spoiler and to demonstrate that it is possible to modify concurrently the range and lateral deviation of the projectile. On one hand a neural network model the variations of the aerodynamic coefficients from RANS calculations. On the other hand, the kriging modeling of the objective and constraint functions benefits from the estimation of the modeling error. This allows defining enrichment criteria ensuring a tradeoff between exploration and exploitation of the geometrical domain. The optimization of the spoiler geometrical parameters leads to the identification of an optimal configuration able to achieve the course corrections abilities targeted. ZDES simulations on this particular configuration have been achieved to form a new fidelity level in addition to the RANS evaluations of the aerodynamic coefficients. These simulations lead to a physical characterization of modifications of the boat-tail flow induced by the presence of the spoiler. A wind tunnel campaign provides a validation step to the optimization methodology developed and offers promising perspectives for future work in terms of experimental data inclusion in a numerical database through multi-level surrogate modeling
Hamad, Rahel. "GIS i kommunal verksamhetsriskanalys vid planering av grundvattenmagasin." Thesis, Linköping University, Department of Computer and Information Science, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6394.
Full textIngen vätska kan ersätta vatten och utan vatten kan inget liv existera. Markens fysikaliska egenskaper och kemiska förhållanden styr spridningen av de föroreningsämnen som före¬kommer i mark och i vatten.
Katrineholms kommun vill i framtiden kunna utnyttja vattenmagasinen i Forssjö. Ett antal observationsrör har placerats i Forssjö, vilket är beläget cirka 8 km sydost om Katrineholm. I dagsläget används inte GIS i kommunen och detta gjorde att jag blev intresserad av vilka möjligheter som GIS skulle kunna tillföra med utgångspunkt i den brunnsdatabas med vatten¬kvalitetsmätningar som finns i kommunen.
Detta examensarbete består av två delar. Den första delen granskar risken för föroreningar från den del av väg 52 mellan Katrineholm och Nyköping som passerar Katrineholmsåsen sydost om Katrineholm. Inom riskkartan visade det sig att de jordlager som täcker akviferen, Katrineholmsåsen, inte ger naturligt skydd åt grundvattnet mot nedträngande föroreningarna. Den metod som används för att beräkna riskerna för förorenat grundvatten är den hydrogeologiska sårbarhetsmodell som Lena Maxe och Per-Olof Johansson har utarbetat i Bedömning av grundvattnets sårbarhet, 1998.
I Katrineholms kommun finns fullständiga data om jordarter och en utmärkt brunnsdatabas. För att utredda risken för en förorening av akviferen i Katrineholmsåsen från väg 52, behövs ett bra verktyg. Detta arbete kommer att visa hur och på vilka sätt GIS kan utföra detta. Under arbetets gång har kontakt tagits med Räddningsverket i Karlstad. Via den kontakten har mycket värdefull information skaffats, till exempel hur genomströmnings¬hastigheter beräknas för föroreningsämnen, vilka program som de använder för att beräkna risker vid spill och utsläpp av kemikalier.
I andra delen av mitt arbete har jag granskat vilken metod som lämpar sig bäst för interpolering av situationen mellan mätpunkterna; kriging eller cokriging, i geostatistiska analyser. För att hitta den bäst anpassade modellen har jag använt ekvationen: fel = r = ύ – v. Här gäller det att söka en modell som ger felet ett värde så nära noll som möjligt.
Utryckning vid utsläpp av bensin, diesel och övriga petroleumprodukter utgjorde 75 % av fallen enligt Räddningsverket insatsstatistik 2000 – 2003. Dessa ämnen ingår i gruppen kemikalier med benämningen NAPL, Non Aqueous Phase Liquid. I mitt arbete har jag koncentrerat mig på hur utsläpp av denna grupp av kemikalier på väg 52 skulle kunna förorena akviferen i Katrineholmsåsen.
Edwards, Adam Michael. "Precision Aggregated Local Models." Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/102125.
Full textDoctor of Philosophy
Occasionally, when describing the relationship between two variables, it may be helpful to use a so-called ``non-parametric" regression that is agnostic to the function that connects them. Gaussian Processes (GPs) are a popular method of non-parametric regression used for their relative flexibility and interpretability, but they have the unfortunate drawback of being computationally infeasible for large data sets. Past work into solving the scaling issues for GPs has focused on ``divide and conquer" style schemes that spread the data out across multiple smaller GP models. While these model make GP methods much more accessible to large data sets they do so either at the expense of local predictive accuracy of global surface continuity. Precision Aggregated Local Models (PALM) is a novel divide and conquer method for GP models that is scalable for large data while maintaining local accuracy and a smooth global model. I demonstrate that PALM can be built quickly, and performs well predictively compared to other state of the art methods. This document also provides a sequential algorithm for selecting the location of each local model, and variations on the basic PALM methodology.
Quirante, Natalia. "Rigorous Design of Chemical Processes: Surrogate Models and Sustainable Integration." Doctoral thesis, Universidad de Alicante, 2017. http://hdl.handle.net/10045/74373.
Full textBueno, Márcio Eduardo Boeira. "Mapeamento da variabilidade e análise espacial de atributos de qualidade físico-químicos dos frutos em pós-colheita e atributos de vigor da planta nas variedades Maxi Gala e Fuji Moore sobre pomar comercial em Vacaria /RS." Universidade do Estado de Santa Catarina, 2013. http://tede.udesc.br/handle/handle/1174.
Full textCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
The cost of apple production has been increasing over the years, and the selling price international and domestic fruit is decreasing. Given this perspective, there is a need for better technification by the fruit growers. The Precision Agriculture (PA) is an indispensable tool for aggregating information in decision-making producers. This study aimed to use the concepts of AP, to design maps of fruit quality, the management of plant vigor and yield maps regionalized in apple orchards. The experiment was conducted in two areas of 0.90 and 1.44 ha of commercial production of Gala and Fuji varieties Maxi Moore, respectively, at São Paulino company RASIP in Vacaria - RS. The quality attributes of the physical-chemical post-harvest fruit were evaluated: average fruit diameter (CMF), firmness (FP), number of seeds per fruit (NSF) and soluble solids (TSS). The attributes of plant vigor were: canopy volume (CV), stem diameter (DC) and fertility index (FI). We also evaluated the production (P). We collected 75 samples for each parameter measured in a grid of 12x10m to 16x12m variety Maxi Gala and Fuji variety to Moore. Analysis was performed using descriptive statistics and spatial analysis through the semivariogram. Possession of the adjusted models in the analysis of the semivariogram was held by the interpolation method of kriging. After, we performed a simple correlation of the parameters and those with strong correlation (≥ 0.50) drew up the cross semivariogram and held by the interpolation method of cokriging. All measurable parameters of the physical and chemical attributes of the fruits in postharvest attributes of plant vigor and production of Gala and Fuji varieties Maxi Moore harvests in 2011 and 2012 showed spatial variability. The 12x10 m sampling grid for Maxi Gala variety was adequate, because only the parameter number of fruits per plant (NFP) in the 2011 range presented below the mesh. Already a 16x12 m sampling grid for the Fuji variety Moore was less suitable for the parameters number of seeds per fruit (NSF), pulp firmness (FP) and Cup Volume (CV), which showed lower reaches in the mesh two crops. The thematic maps of these parameters allowed the development of theoretical management units, seen not meet recommendations of class divisions for the varieties studied. Production parameters (P) versus Diameter Stem (DC) showed a strong correlation in the variety in the 2011 Maxi Gala. In 2011 and 2012 vintages parameters Volume Cup (VC) versus Diameter Stem (DC) also showed a strong correlation. Thus in the 2011 reduced the collection of 15 samples of crop production and in 2012 was reduced to collecting 20 samples of canopy volume, the method of cokriging. For the Fuji variety Moore parameters Volume Cup (VC) versus Diameter Stem (DC) showed a strong correlation in the 2011 and 2012 vintages. In the 2011 parameters showed dependence with the same number of samples by the cokriging method. Already in 2012 there was no such dependence
O custo de produção da maçã vem aumentando ao longo dos anos, sendo que o preço de venda internacional e nacional da fruta está diminuindo. Diante desta perspectiva, existe a necessidade de uma melhor tecnificação por parte dos fruticultores. A Agricultura de precisão (AP) é uma ferramenta indispensável para agregar informações na tomada de decisão dos produtores. O presente trabalho teve como objetivo utilizar os conceitos de AP, para projetar mapas da qualidade de frutos, do manejo do vigor das plantas e mapas de produtividade regionalizada na cultura da macieira. O experimento foi conduzido em duas áreas de 0,90 e 1,44 ha de produção comercial das variedades Maxi Gala e Fuji Moore, respectivamente, na Fazenda São Paulino da empresa RASIP, em Vacaria RS. Os atributos de qualidade físico-químicos dos frutos em pós-colheita avaliados foram: calibre médio dos frutos (CMF), firmeza de polpa (FP), número de sementes por fruto (NSF) e sólidos solúveis totais (SST). Os atributos de vigor das plantas avaliados foram: volume de copa (VC), diâmetro de caule (DC) e índice de fertilidade (IF). Avaliou-se também a produção (P). Foram coletadas 75 amostras para cada parâmetro mensurável em uma malha de 12x10m para variedade Maxi Gala e 16x12m para variedade Fuji Moore. Foi realizada análise estatística descritiva dos dados e a análise espacial através dos semivariogramas. De posse dos modelos ajustados na análise dos semivariogramas realizou-se a interpolação pelo método da krigagem. Após, foi realizada a correlação simples dos parâmetros e os que apresentaram forte correlação (≥ 0,50) elaborou-se os semivariogramas cruzados e realizou-se a interpolação pelo método da cokrigagem. Todos os parâmetros mensuráveis dos atributos físico-químicos dos frutos em pós-colheita, atributos de vigor das plantas e produção das variedades Maxi Gala e Fuji Moore nas safras 2011 e 2012 apresentaram variabilidade espacial. A malha de amostragem 12x10 m para a variedade Maxi Gala mostrou-se adequada, pois somente o parâmetro Número de Frutos por planta (NFP) na safra 2011 apresentou alcance inferior à malha. Já a malha de amostragem 16x12 m para a variedade Fuji Moore mostrou-se menos adequada para os parâmetros Número de Sementes por Fruto (NSF), Firmeza de polpa (FP) e Volume de Copa (VC), que apresentaram alcances inferiores à malha nas duas safras. Os mapas temáticos elaborados dos parâmetros avaliados permitiram a elaboração de unidades de manejo teóricas, visto não se encontrar recomendações de divisões de classes para as variedades estudadas. Os parâmetros Produção (P) versus Diâmetro de Caule (DC) apresentaram forte correlação na variedade Maxi Gala na safra 2011. Nas safras 2011 e 2012 os parâmetros Volume de Copa (VC) versus Diâmetro de Caule (DC) também apresentaram forte correlação. Desta forma na safra 2011 reduziu-se a coleta de 15 amostras da produção e na safra 2012 reduziu-se a coleta de 20 amostras do volume de copa, pelo método da cokrigagem. Para a variedade Fuji Moore os parâmetros Volume de Copa (VC) versus Diâmetro de Caule (DC) apresentaram forte correlação nas safras 2011 e 2012. Na safra 2011 os parâmetros apresentaram dependência com o mesmo número de amostras pelo método as cokrigagem. Já em 2012 não houve essa dependência
Aidoo, Eric. "Geostatistical modelling of recreational fishing data: A fine-scale spatial analysis." Thesis, Edith Cowan University, Research Online, Perth, Western Australia, 2016. https://ro.ecu.edu.au/theses/1813.
Full textLiu, Xuyuan. "Statistical validation and calibration of computer models." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/39478.
Full textAmbachtsheer, Pamela. "Combined Use of Models and Measurements for Spatial Mapping of Concentrations and Deposition of Pollutants." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/1261.
Full textHöfler, Veit, Christine Wessollek, and Pierre Karrasch. "Modelling prehistoric terrain Models using LiDAR-data: A geomorphological approach." SPIE, 2015. https://tud.qucosa.de/id/qucosa%3A35056.
Full textAckerman-Alexeeff, Stacey Elizabeth. "Measurement error in environmental exposures: Statistical implications for spatial air pollution models and gene environment interaction tests." Thesis, Harvard University, 2013. http://dissertations.umi.com/gsas.harvard:11077.
Full textTresidder, Esmond. "Accelerated optimisation methods for low-carbon building design." Thesis, De Montfort University, 2014. http://hdl.handle.net/2086/10512.
Full textSarmah, Dipsikha. "Evaluation of Spatial Interpolation Techniques Built in the Geostatistical Analyst Using Indoor Radon Data for Ohio,USA." University of Toledo / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1350048688.
Full textBa, Shan. "Multi-layer designs and composite gaussian process models with engineering applications." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/44751.
Full textKleisner, Kristin Marie. "A Spatio-Temporal Analysis of Dolphinfish; Coryphaena hippurus, Abundance in the Western Atlantic: Implications for Stock Assessment of a Data-Limited Pelagic Resource." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/137.
Full textPereira, Taiguã Corrêa. "O desconhecido do pouco conhecido : padrão espacial de riqueza e lacunas de conhecimento em plantas (Fabales: Fabaceae) na caatinga." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/4475.
Full textA biodiversidade é distribuída de forma heterogênea através do planeta Terra. Embora a discussão sobre quais fatores determinam os padrões espaciais da biodiversidade continue controversa, o simples conhecimento dos seus componentes é um desafio ainda maior em algumas regiões. Assim, conhecer o quanto ainda há para ser estudado ou descoberto é fundamental para a ciência, e a falta de conhecimento sobre a distribuição geográfica das espécies é considerado um dos principais problemas enfrentados em estudos sobre a biodiversidade, especialmente em países “megadiversos” como o Brasil. O Bioma Caatinga tem sido historicamente reconhecido com um dos menos conhecidos e valorizados quanto a diversidade biológica, devido à ideia equivocada de sua baixa diversidade e endemismo e elevado grau de antropização. Considerando a dominância da família Fabaceae na Caatinga, quanto à riqueza e abundância regional, investigamos o padrão espacial da riqueza de espécies de Fabaceae no bioma, buscando determinar quais os fatores ambientais responsáveis pela variação espacial da sua riqueza de espécies. Além disso, elaboramos um modelo estatístico espacial de diversidade de Fabaceae na Caatinga a partir da estrutura espacial das assembleias conhecidas e dos seus determinantes ambientais, a fim de estimar o déficit de conhecimento sobre a distribuição (déficit wallaceano) da Família na Caatinga. Obtivemos 220.781 registros, dos quais menos de 25% foram válidos. A partir desses registros, encontramos o total de 1.310 espécies de 198 gêneros. A riqueza predita pelo modelo espacial variou de 92 a 283 espécies ao longo do espaço e foi melhor descrita pelo esforço amostral, aspectos do solo e topografia. A partir da medida de discrepância entre valores preditos e observados de riqueza de espécies, estimamos valores de déficit Wallaceano, chegando a 192 espécies em uma única localidade. O número total de espécies encontrado neste trabalho representa um incremento expressivo na riqueza conhecida de espécies da família na Caatinga. A seleção de fatores não climático como principais preditores de riqueza indica maior influência da topografia e do solo na escala regional. E também a importância do substrato no estabelecimento de comunidades vegetais no semiárido. O déficit Wallaceano estimado evidencia uma deficiência crônica e espacialmente heterogênea no conhecimento da flora regional. A persistência de lacunas tão expressivas no conhecimento, somada a cobertura reduzida de áreas protegidas no Bioma evidencia um risco corrente de perdas significativas de diversidade biológica com sérias implicações para a conservação do Bioma.
Nachar, Stéphane. "Optimisation de structures viscoplastiques par couplage entre métamodèle multi-fidélité et modèles réduits." Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLN051/document.
Full textEngineering simulation provides the best design products by allowing many design options to be quickly explored and tested, but fast-time-to-results requirement remains a critical factor to meet aggressive time-to-market requirements. In this context, using high-fidelity direct resolution solver is not suitable for (virtual) charts generation for engineering design and optimization.Metamodels are commonly considered to explore design options without computing every possibility, but if the behavior is nonlinear, a large amount of data is still required. A possibility is to use further data sources to generate a multi-fidelity surrogate model by using model reduction. Model reduction techniques constitute one of the tools to bypass the limited calculation budget by seeking a solution to a problem on a reduced order basis (ROB).The purpose of the present work is an online method for generating a multi-fidelity metamodel nourished by calculating the quantity of interest from the basis generated on-the-fly with the LATIN-PGD framework for elasto-viscoplastic problems. Low-fidelity fields are obtained by stopping the solver before convergence, and high-fidelity information is obtained with converged solution. In addition, the solver ability to reuse information from previously calculated PGD basis is exploited.This manuscript presents the contributions to multi-fidelity metamodels and the LATIN-PGD method with the implementation of a multi-parametric strategy. This coupling strategy was tested on three test cases for calculation time savings of more than 37x
Lee, Hyung-Jin. "Regional forecasting of hydrologic parameters." Ohio : Ohio University, 1996. http://www.ohiolink.edu/etd/view.cgi?ohiou1178223662.
Full textBoopathy, Komahan. "Uncertainty Quantification and Optimization Under Uncertainty Using Surrogate Models." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1398302731.
Full textWeighman, Kristi Kay. "Mapping dynamic exposure: constructing GIS models of spatiotemporal heterogeneity in artificial stream systems." Bowling Green State University / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1555337508685485.
Full textKang, Lei. "Reduced-Dimension Hierarchical Statistical Models for Spatial and Spatio-Temporal Data." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1259168805.
Full textHuang, Fang. "Modeling patterns of small scale spatial variation in soil." Link to electronic thesis, 2006. http://www.wpi.edu/Pubs/ETD/Available/etd-011106-155345/.
Full textKeywords: spatial variations; nested random effects models; semivariogram models; kriging methods; multiple logistic regression models; missing; multiple imputation. Includes bibliographical references (p. 35-36).
Lawal, Najib. "Modelling and multivariate data analysis of agricultural systems." Thesis, University of Manchester, 2015. https://www.research.manchester.ac.uk/portal/en/theses/modelling-and-multivariate-data-analysis-of-agricultural-systems(f6b86e69-5cff-4ffb-a696-418662ecd694).html.
Full textBilicz, Sandor. "Application of Design-of-Experiment Methods and Surrogate Models in Electromagnetic Nondestructive Evaluation." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00601753.
Full textKroetz, Henrique Machado. "Meta-modelagem em confiabilidade estrutural." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/18/18134/tde-08042015-162956/.
Full textThe application of numerical simulations to structural reliability problems is often associated with high computational costs, given the small probability of failure inherent to the structures. Although many cases can be addressed using variance reduction techniques, solving problems involving large number of degrees of freedom, nonlinear and dynamic responses, and problems of optimization in the presence of uncertainties are sometimes still infeasible to solve by this approach. Such problems, however, can be solved by analytical representations that approximate the response that would be obtained with the use of more complex computational models, called meta-models. This work deals with the collection, assimilation, computer programming and comparison of modern meta-modeling techniques in the context of structural reliability, using representations constructed from artificial neural networks, polynomial chaos expansions and Kriging. These techniques are implemented in the computer program StRAnD - Structural Reliability Analysis and Design, developed at the Department of Structural Engineering, USP; thus resulting in a permanent benefit to structural reliability analysis at the University of São Paulo.
Falk, Matthew Gregory. "Incorporating uncertainty in environmental models informed by imagery." Thesis, Queensland University of Technology, 2010. https://eprints.qut.edu.au/33235/1/Matthew_Falk_Thesis.pdf.
Full textThenon, Arthur. "Utilisation de méta-modèles multi-fidélité pour l'optimisation de la production des réservoirs." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066100/document.
Full textPerforming flow simulations on numerical models representative of oil deposits is usually a time consuming task in reservoir engineering. The substitution of a meta-model, a mathematical approximation, for the flow simulator is thus a common practice to reduce the number of calls to the flow simulator. It permits to consider applications such as sensitivity analysis, history-matching, production estimation and optimization. This thesis is about the study of meta-models able to integrate simulations performed at different levels of accuracy, for instance on reservoir models with various grid resolutions. The goal is to speed up the building of a predictive meta-model by balancing few expensive but accurate simulations, with numerous cheap but approximated ones. Multi-fidelity meta-models, based on co-kriging, are thus compared to kriging meta-models for approximating different flow simulation outputs. To deal with vectorial outputs without building a meta-model for each component of the vector, the outputs can be split on a reduced basis using principal component analysis. Only a few meta-models are then needed to approximate the main coefficients in the new basis. An extension of this approach to the multi-fidelity context is proposed. In addition, it can provide an efficient meta-modelling of the objective function when used to approximate each production response involved in the objective function definition. The proposed methods are tested on two synthetic cases derived from the PUNQ-S3 and Brugge benchmark cases. Finally, sequential design algorithms are introduced to speed-up the meta-modeling process and exploit the multi-fidelity approach
Canaud, Matthieu. "Estimation de paramètres et planification d’expériences adaptée aux problèmes de cinétique - Application à la dépollution des fumées en sortie des moteurs." Thesis, Saint-Etienne, EMSE, 2011. http://www.theses.fr/2011EMSE0619/document.
Full textPhysico-chemical models designed to represent experimental reality may prove to be inadequate. This is the case of nitrogen oxide trap, used as an application support of our thesis, which is a catalyst system treating the emissions of the diesel engine. The outputs are the curves of concentrations of pollutants, which are functional data, depending on scalar initial concentrations.The initial objective of this thesis is to propose experiental design that are meaningful to the user. However, the experimental design relying on models, most of the work has led us to propose a statistical representation taking into account the expert knowledge, and allows to build this plan.Three lines of research were explored. We first considered a non-functional modeling with the use of kriging theory. Then, we took into account the functional dimension of the responses, with the application and extension of varying coefficent models. Finally, starting again from the original model, we developped a model depending on the kinetic parameters of the inputs (scalar) using a nonparametric representation.To compare the methods, it was necessary to conduct an experimental campaign, and we propose an exploratory design approach, based on maximum entropy
Durrande, Nicolas. "Étude de classes de noyaux adaptées à la simplification et à l’interprétation des modèles d’approximation. Une approche fonctionnelle et probabiliste." Thesis, Saint-Etienne, EMSE, 2011. http://www.theses.fr/2011EMSE0631/document.
Full textThe framework of this thesis is the approximation of functions for which thevalue is known at limited number of points. More precisely, we consider here the so-calledkriging models from two points of view : the approximation in reproducing kernel Hilbertspaces and the Gaussian Process regression.When the function to approximate depends on many variables, the required numberof points can become very large and the interpretation of the obtained models remainsdifficult because the model is still a high-dimensional function. In light of those remarks,the main part of our work adresses the issue of simplified models by studying a key conceptof kriging models, the kernel. More precisely, the following aspects are adressed: additivekernels for additive models and kernel decomposition for sparse modeling. Finally, wepropose a class of kernels that is well suited for functional ANOVA representation andglobal sensitivity analysis
Guerra, Jonathan. "Optimisation multi-objectif sous incertitudes de phénomènes de thermique transitoire." Thesis, Toulouse, ISAE, 2016. http://www.theses.fr/2016ESAE0024/document.
Full textThis work aims at solving multi-objective optimization problems in the presence of uncertainties and costly numerical simulations. A validation is carried out on a transient thermal test case. First of all, we develop a multi-objective optimization algorithm based on kriging and requiring few calls to the objective functions. This approach is adapted to the distribution of the computations and favors the restitution of a regular approximation of the complete Pareto front. The optimization problem under uncertainties is then studied by considering the worst-case and probabilistic robustness measures. The superquantile integrates every event on which the output value is between the quantile and the worst case. However, it requires an important number of calls to the uncertain objective function to be accurately evaluated. Few methods give the possibility to approach the superquantile of the output distribution of costly functions. To this end, we have developed an estimator based on importance sampling and kriging. It enables to approach superquantiles with little error and using a limited number of samples. Moreover, the setting up of a coupling with the multi-objective algorithm allows to reuse some of those evaluations. In the last part, we build spatio-temporal surrogate models capable of predicting non-linear, dynamic and long-term in time phenomena by using few learning trajectories. The construction is based on recurrent neural networks and a construction facilitating the learning is proposed
Mosquera, Meza Rolando. "Interpolation sur les variétés grassmanniennes et applications à la réduction de modèles en mécanique." Thesis, La Rochelle, 2018. http://www.theses.fr/2018LAROS008/document.
Full textThis dissertation deals with interpolation on Grassmann manifolds and its applications to reduced order methods in mechanics and more generally for systems of evolution partial differential systems. After a description of the POD method, we introduce the theoretical tools of grassmannian geometry which will be used in the rest of the thesis. This chapter gives this dissertation a mathematical rigor in the performed algorithms, their validity domain, the error estimate with respect to the grassmannian distance on one hand and also a self-contained character to the manuscript. The interpolation on Grassmann manifolds method introduced by David Amsallem and Charbel Farhat is afterward presented. This method is the starting point of the interpolation methods that we will develop in this thesis. The method of Amsallem-Farhat consists in chosing a reference interpolation point, mapping forward all interpolation points on the tangent space of this reference point via the geodesic logarithm, performing a classical interpolation on this tangent space and mapping backward the interpolated point to the Grassmann manifold by the geodesic exponential function. We carry out the influence of the reference point on the quality of the results through numerical simulations. In our first work, we present a grassmannian version of the well-known Inverse Distance Weighting (IDW) algorithm. In this method, the interpolation on a point can be considered as the barycenter of the interpolation points where the used weights are inversely proportional to the distance between the considered point and the given interpolation points. In our method, denoted by IDW-G, the geodesic distance on the Grassmann manifold replaces the euclidean distance in the standard framework of euclidean spaces. The advantage of our algorithm that we show the convergence undersome general assumptions, does not require a reference point unlike the method of Amsallem-Farhat. Moreover, to carry out this, we finally proposed a direct method, thanks to the notion of generalized barycenter instead of an earlier iterative method. However, our IDW-G algorithm depends on the choice of the used weighting coefficients. The second work deals with an optimal choice of the weighting coefficients, which take into account of the spatial autocorrelation of all interpolation points. Thus, each weighting coefficient depends of all interpolation points an not only on the distance between the considered point and the interpolation point. It is a grassmannian version of the Kriging method, widely used in Geographic Information System (GIS). Our grassmannian Kriging method require also the choice of a reference point. In our last work, we develop a grassmannian version of Neville's method which allow the computation of the Lagrange interpolation polynomial in a recursive way via the linear interpolation of two points. The generalization of this algorithm to grassmannian manifolds is based on the extension of interpolation of two points (geodesic/straightline) that we can do explicitly. This algorithm does not require the choice of a reference point, it is easy to implement and very quick. Furthermore, the obtained numerical results are notable and better than all the algorithms described in this dissertation
Barbarroux, Loïc. "Contributions à la modélisation multi-échelles de la réponse immunitaire T-CD8 : construction, analyse, simulation et calibration de modèles." Thesis, Lyon, 2017. http://www.theses.fr/2017LYSEC026/document.
Full textUpon infection by an intracellular pathogen, the organism triggers a specific immune response,mainly driven by the CD8 T cells. These cells are responsible for the eradication of this type of infections and the constitution of the immune repertoire of the individual. The immune response is constituted by many processes which act over several interconnected physical scales (intracellular scale, single cell scale, cell population scale). This biological phenomenon is therefore a complex process, for which it is difficult to observe or measure the links between the different processes involved. We propose three multiscale mathematical models of the CD8 immune response, built with different formalisms but related by the same idea : to make the behavior of the CD8 T cells depend on their intracellular content. For each model, we present, if possible, its construction process based on selected biological hypothesis, its mathematical study and its ability to reproduce the immune response using numerical simulations. The models we propose succesfully reproduce qualitatively and quantitatively the CD8 immune response and thus constitute useful tools to further investigate this biological phenomenon
Zumpe, Martin Kai. "Stabilité macroéconomique, apprentissage et politique monétaire : une approche comparative : modélisation DSGE versus modélisation multi-agents." Thesis, Bordeaux 4, 2012. http://www.theses.fr/2012BOR40022/document.
Full textThis thesis analyses the role of learning in two different modelling frameworks. In the new canonicalmodel with adaptive learning, the most remarkable characteristics of the learning dynamics deal withthe capacity of monetary policy rules to guaranty convergence to the rational expectations equilibrium.The transmission mechanism of the monetary policy is based on the substitution effect associated to theconsumption channel. In the case of an agent-based model which relaxes some restrictive assumptionsof the new canonical model - but is endowed with a similar structure - aggregate variables evolve atsome distance from the rational expectations equilibrium. Monetary policy has a marginal impact onthe agregated variables via the wealth effect of the consumption channel. When agents learn accordingto an evolutionnary social learning process, the economy converges to regions of low economic activity.The introduction of a process where agents learn individually by using their mental models induces lessdepressive learning dynamics. These differences between the two modelling frameworks show that thegeneralisation of the results of the new canonical model is not easy to achieve
Jian, Yi Ru, and 簡宜如. "Application of kriging and cokriging on predicting spatial variability of soil properties." Thesis, 1995. http://ndltd.ncl.edu.tw/handle/50688874112080000646.
Full text國立臺灣大學
農業化學研究所
83
Spatial variability of soil properties was investigated by krig ing and cokriging from 132 point observartions in an area of 10 square kilometer in Changhua county. Some soil properties such as P, Ca, Mg, Fe, sand%, silt%, clay% and sum of exchangeable bases(SEB) were selected for this study. The structural analysis of the soil properties applied in the study showed that the pro-perties were moderately spatial dependent. The spatial distributions of the soil properties predicted by minimum sampling densities were all significantly correlated (p<0.1%) with those by maximum densities. The mean absolute errors and mean square of errors between actually observed and estimated values obtained by cokriging using auxiliary variables oversampled with respect to the main variable. SEB, sand%, silt% and clay% were highly inter- correlated in the study, so they could be chosen as the main or auxiliary variables. Topsoil sand%, silt% and clay% were functioned as auxiliary variables in predicting topsoil SEB, topsoil SEB and clay% as auxiliary variables in predicting subsoil SEB. The result suggested that both ordinary kriging and cokriging can be used for predicting the spatial distribution of large-scale sampled soil properties. Providing improved estimates with rela-tive reduced mean estimation error and increasing the efficiency of sampling, cokriging can be an effective technique for predicting the spatial variability of soil properties.