• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 8
  • 5
  • 1
  • 1
  • Tagged with
  • 15
  • 15
  • 7
  • 7
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 4
  • 3
  • 3
  • 3
  • 2
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Calibration of traffic models in SIDRA

Ekman, Anna-Karin January 2013 (has links)
This thesis studies calibration of SIDRA Intersection roundabout models. The calibration has been performed with three different methods; manual calibration of gap-acceptance parameters, manual calibration of the parameter environment factor and automatic calibration of the environment factor based on optimization. The main aim has been to evaluate and compare 3 the three methods. One part of the purpose was also to test the possibility of finding a general value of environment factor by testing a few different types of models. SIDRA Intersection is a micro-analytical model used for capacity and performance estimations. The capacity model is based on gap-acceptance theory where follow-up headway and critical gap have a great impact. An application for automatic calibration was developed in Microsoft Excel/VBA. The calibration process is based Differential evolution and the cost function uses root mean square percent error where capacity and average delay are used as performance measures. The application has been tested with a test model at first to make sure the calibration is correct. The application has then been tested on data from a site in Farsta, Stockholm. For this site all three calibration methods, the two manual and the automatic, has been tested. The results show that all three methods performed equally well, with only small differences in precision. The most effective method considering results and time required for process was the manual calibration of environment factor.In the last part of this project the method for manual calibration of environment factor was tested with three more models with different characteristics in order to investigate the possibility of finding one value for environment factor suitable for all approaches. However the tests show difference in environment factor between small and large roundabouts and difficulties to set one value for environment factor for two-lane approaches.
2

Calibration and Analysis of the MESH Hydrological Model applied to Cold Regions

MacLean, Angela 30 September 2009 (has links)
Concerns regarding climate change have brought about an increased interest in cold region hydrology, leading to the formation of the IP3 research network. This work is part of the IP3 Network, which has the overall goal to evaluate and demonstrate improved predictions of hydrological and atmospheric fields for cold regions. As such this thesis involves a series of calibration and validation experiments on the MESH hydrological model (used by IP3 for predictions) with two cold region case studies. The first case study is the very well instrumented Reynolds Creek Experimental Watershed in Idaho, USA and the second case study is the Wolf Creek watershed in the Yukon Territory. As the MESH model is still in the development phase, a critical component of model development is a thorough analysis of model setup and performance. One intention of this research is to provide feedback for future development of the MESH hydrological model. The Reynolds Creek site was modeled as part of this thesis work. This site was chosen based on the long term, highly distributed and detailed data set. The second site, Wolf Creek, was used for a simplified case study. Models of both case study sites were calibrated and validated to carefully evaluate model performance. Reynolds Creek was calibrated as a single objective problem as well as multi-objective problem using snow water equivalent data and streamflow data for multiple sites. The hydrological simulations for Wolf Creek were fair; further calibration effort and a more detailed examination of the model setup would have likely produced better results. Calibration and validation of Reynolds Creek produced very good results for streamflow and snow water equivalent at multiple sites though out the watershed. Calibrating streamflow generated a very different optimal parameter set compared to calibrating snow water equivalent or calibrating to both snow water equivalent and streamflow in a multi-objective framework. A weighted average multi-objective approach for simultaneously calibrating to snow water equivalent and streamflow can be effective as it yields a reasonable solution that improves the single objective snow water equivalent results without degrading the single objective streamflow results.
3

Calibration and Analysis of the MESH Hydrological Model applied to Cold Regions

MacLean, Angela 30 September 2009 (has links)
Concerns regarding climate change have brought about an increased interest in cold region hydrology, leading to the formation of the IP3 research network. This work is part of the IP3 Network, which has the overall goal to evaluate and demonstrate improved predictions of hydrological and atmospheric fields for cold regions. As such this thesis involves a series of calibration and validation experiments on the MESH hydrological model (used by IP3 for predictions) with two cold region case studies. The first case study is the very well instrumented Reynolds Creek Experimental Watershed in Idaho, USA and the second case study is the Wolf Creek watershed in the Yukon Territory. As the MESH model is still in the development phase, a critical component of model development is a thorough analysis of model setup and performance. One intention of this research is to provide feedback for future development of the MESH hydrological model. The Reynolds Creek site was modeled as part of this thesis work. This site was chosen based on the long term, highly distributed and detailed data set. The second site, Wolf Creek, was used for a simplified case study. Models of both case study sites were calibrated and validated to carefully evaluate model performance. Reynolds Creek was calibrated as a single objective problem as well as multi-objective problem using snow water equivalent data and streamflow data for multiple sites. The hydrological simulations for Wolf Creek were fair; further calibration effort and a more detailed examination of the model setup would have likely produced better results. Calibration and validation of Reynolds Creek produced very good results for streamflow and snow water equivalent at multiple sites though out the watershed. Calibrating streamflow generated a very different optimal parameter set compared to calibrating snow water equivalent or calibrating to both snow water equivalent and streamflow in a multi-objective framework. A weighted average multi-objective approach for simultaneously calibrating to snow water equivalent and streamflow can be effective as it yields a reasonable solution that improves the single objective snow water equivalent results without degrading the single objective streamflow results.
4

Automated calibration of a tractor transmission control unit

Körtgen, Christopher, Morandi, Gabriele, Jacobs, Georg, Straßburger, Felix 28 April 2016 (has links) (PDF)
This paper presents an approach for an automated calibration process for electronic control units (ECU) of power split transmissions in agricultural tractors. Today the calibration process is done manually on a prototype tractor by experts. In order to reduce development costs the calibration process is shifted from prototype testing to software modelling. Simultaneous optimization methods are used within the software modelling to calculate new parameters. The simultaneous optimization includes objective evaluation methods to evaluate the tractor behaviour. With the combination of both methods inside the software modelling, the calibration process can be automated. The success of this approach depends on the quality of the software modelling. Therefore the identification of the initial prototype behaviour and the fitting of the tractor software model is done at the beginning. At the end of the automated calibration the validation and fine-tuning of the calculated parameters are done on the real tractor. These steps are condensed to a five step automated calibration process which includes simultaneous optimization and objective evaluation methods in several applications. After the detailed discussion of this automated calibration process one function of the ECU (one transmission component) will be calibrated through this process as example.
5

Leitura automática de dispositivos mostradores analógicos de instrumentos de medição utilizando visão computacional. / Automatic reading of measurement devices analogical displays using computer vision.

Almeida, Rynaldo Zanotele Hemerly de 22 May 2006 (has links)
Propõe-se um sistema de visão computacional para leitura automática de dispositivos mostradores analógicos de instrumentos de medição que não possuem interface de comunicação digital. Esse sistema pode ser aplicado na automação de processos de calibração desses instrumentos ou em outros ensaios em que sejam feitas leituras repetitivas por um operador humano. Espera-se reduzir o tempo de leitura e os custos envolvidos nos processos e alcançar exatidão e incerteza ao menos equivalentes aos da leitura humana. A abordagem proposta se baseia na comparação da inclinação do ponteiro com as inclinações das marcas de escala do dispositivo mostrador. Em uma primeira etapa realiza-se o reconhecimento das marcas de escala e a correspondência de cada marca a um valor de leitura a partir de três imagens capturadas e algumas informações consideradas conhecidas como o número de escalas, o número de marcas principais por escala e os valores associados a essas marcas principais. Em seguida parte-se para uma segunda etapa em que para cada nova imagem capturada é obtido um valor de leitura por meio da interpolação entre valores de inclinações calculados e os valores de leitura associados às marcas de escala. Uma análise de incerteza de leitura mostra que para os instrumentos estudados e equipamentos empregados (câmera e lentes) a leitura automática é compatível com a leitura humana e que a incerteza poderia ser eventualmente melhorada. Foram realizados diversos testes de leitura automática. Os resultados obtidos confirmaram as expectativas de incertezas e a ocorrência de erros mais significativos foi da ordem de apenas um por cento o que revela a robustez do método para utilização real. / A computer vision system for automatic reading of measurement devices analogical displays which do not have a digital communication interface is proposed. This system could be applied for the automation of these devices calibration processes or in other assays in which repetitive readings are done by man. It is expected a reduction in time spent and costs involved and an achievement of accuracy and uncertainty at least equivalent to those attained in human readings. The approach is based on the comparison between the pointer slope and the display device scale marks slope. In a first step the scale marks are identified and a reading value is attributed to each mark from three captured images and some assumed known data as the number of scales, the number of the main marks per scale and the corresponding values associated with these main marks. Then, in a second step, an reading value is attained to each new captured image through the interpolation between the calculated slopes figures and the associated marks reading values. An reading uncertainty analysis shows that considering the studied instruments and the employed devices (camera and lens) the automatic reading is consistent with the human reading and the uncertainty could be eventually improved. Several automatic reading tests were carried out. The results confirmed the expectations of uncertainties and the meaningful error rate was about only one per cent revealing the methods robustness to real application.
6

Calibração multiobjetivo do SWMM aplicada à transformação chuva-vazão / Multiobjective calibration of SWMM applied to rainfall-runoff transformation

Shinma, Taís Arriero 24 May 2011 (has links)
Um calibrador automático multiobjetivo para o Storm Water Management Model (SWMM) foi desenvolvido utilizando o método de otimização multiobjetivo Non Dominated Sorting Genetic Algorithm (NSGA II) com elistismo controlado (Deb & Goel, 2001). O programa utiliza o código fonte do SWMM na etapa de avaliação das soluções, para determinar o valor das vazões simuladas, utilizado no cálculo das funções objetivo (FOs). Os testes do calibrador foram aplicados a dois sistemas diferentes, sendo o primeiro uma bacia exemplo hipotética disponibilizada no pacote de instalação do SWMM e o segundo a bacia do córrego do Gregório, localizada no município de São Carlos (SP). Foi realizada a análise de sensibilidade para os dois sistemas, visando determinar os parâmetros a serem calibrados. De modo geral, a porcentagem de áreas impermeáveis e os parâmetros de rugosidade e de infiltração apresentaram maior influência sobre a resposta do sistema em termos de vazão de pico e volume total escoado das bacias. O programa desenvolvido se mostrou eficiente para ambos os sistemas calibrados, com coeficientes de eficiência de Nash & Sutcliffe (1970) médios de 0,99 para a bacia exemplo e 0,87 para a bacia do córrego do Gregório, respectivamente, com um número reduzido de iterações. Construído o calibrador, testes foram realizados para identificar a melhor combinação de FOs e a abordagem multievento mais eficiente. Para tanto, foram testadas 55 diferentes combinações de FOs duas a duas. Os resultados evidenciaram que a melhor combinação testada foi a F2-F6, e a abordagem multievento mais eficiente foi a avaliação da médias das FOs, considerando todos os eventos utilizados na etapa de calibração. Cabe ressaltar que estas conclusões se aplicam somente ao sistema considerado neste estudo. Por fim, a validação comprovou a eficiência do calibrador, aplicada a 10 eventos distintos registrados na bacia do córrego do Gregório, com coeficiente de eficiência médio de 0,84. / An automatic multiobjective calibrator for the Storm Water Management Model (SWMM) was developed using the Non Dominated Sorting Genetic Algorithm (NSGA II) method with controlled elitism (Deb & Goel, 2001). The software uses the SWMM source code for evaluating the solutions, to determine the simulated flow values, used in the objective functions (OFs) calculation. The calibrator tests were applied on two different systems, a hypothetical example basin provided jointly to the SWMM installation package, and the basin of Gregório stream, located in São Carlos (SP). The sensitivity analysis was performed for both systems to determine the parameters to be calibrated. Generally, the percent of imperviousness, the roughness and infiltration parameters variations resulted in large modifications on the system response in terms of peak flow and total runoff volume. The developed software proved to be efficient for both calibrated systems, presenting an average of the Nash & Sutcliffe (1970) efficiency coeficient of 0.99 and 0.87 for the example basin and the Gregório stream basin, respectively, with a few number of iterations. After the calibrator built, tests were conducted aiming to identify the best OFs combination and the more efficient multievent approach. Thus, 55 different combinations in pairs of OFs were tested. The results showed that the best combination tested was the F2-F6 and most efficient multievent approach was the evaluation of the OFs means, considering all the calibration events. It is worth noting that these conclusions apply only to the system considered in this study. Finally, the validation confirmed the calibrator efficiency, applied to 10 different events recorded in the Gregório stream basin, presenting an average of the efficiency coeficient of 0.84.
7

Avaliação de incertezas na calibração automática do modelo SWMM / Uncertainty evaluation in the automatic calibration of SWMM

Shinma, Taís Arriero 05 November 2015 (has links)
Este trabalho é referente ao desenvolvimento de um calibrador multiobjetivo automático do modelo SWMM (Storm Water Management Model), e avaliação de algumas fontes de incertezas presentes no processo de calibração, visando à representação satisfatória da transformação chuva-vazão. O código foi escrito em linguagem C, e aplica os conceitos do método de otimização multiobjetivo NSGAII (Non Dominated Sorting Genetic Algorithm) com elitismo controlado, além de utilizar o código fonte do modelo SWMM para a determinação das vazões simuladas. Paralelamente, também foi criada uma interface visual, para melhorar a facilidade de utilização do calibrador. Os testes do calibrador foram aplicados a três sistemas diferentes: um sistema hipotético disponibilizado no pacote de instalação do SWMM; um sistema real de pequenas dimensões, denominado La Terraza, localizado no município de Sierra Vista, Arizona (EUA); e um sistema de maiores dimensões, a bacia hidrográfica do Córrego do Gregório, localizada no município de São Carlos (SP). Os resultados indicam que o calibrador construído apresenta, em geral, eficiência satisfatória, porém é bastante dependente da qualidade dos dados observados em campo e dos parâmetros de entrada escolhidos pelo usuário. Foi demonstrada a importância da escolha dos eventos utilizados na calibração, do estabelecimento de limites adequados nos valores das variáveis de decisão, da escolha das funções objetivo e, principalmente, da qualidade e representatividade dos dados de monitoramento pluvio e fluviométrico. Conclui-se que estes testes desenvolvidos contribuem para o entendimento mais aprofundado dos processos envolvidos na modelagem e calibração, possibilitando avanços na confiabilidade dos resultados da modelagem. / This project refers to the development of an automatic multi-objective calibrator for the SWMM (Storm Water Management Model), and the evaluation of some uncertainties sources inherent to the calibration process, aiming to a satisfactory rainfall-runoff transformation representation. The code was written in C language, and applies the concepts of the multi-objective optimization method NSGAII (Non Dominated Sorting Genetic Algorithm) with controlled elitism, using the source code of SWMM to calculate the simulated flow. In addition, a visual interface was also created to improve the calibrators usability. The calibrator tests were applied to three different systems: a hypothetical system available in the SWMM installation package; a real system of small dimensions, called La Terraza, located in the city of Sierra Vista, Arizona (USA); and a large dimensions system, the watershed of Gregório Stream, located in São Carlos (SP). The results indicate that the calibrator built presents, in general, satisfactory efficiency, although it is very dependent on the observed data quality and the input parameters selected by the user. The importance of the events chosen for calibration, the settlement of appropriate limits on the decision variables values, the objective functions choice, and especially the quality and representativeness of the rainfall and runoff monitoring data were demonstrated. We conclude that these performed tests contribute to the thorough understanding of the processes involved in modeling and calibration, enabling advances in the modeling results reliability.
8

Avaliação de incertezas na calibração automática do modelo SWMM / Uncertainty evaluation in the automatic calibration of SWMM

Taís Arriero Shinma 05 November 2015 (has links)
Este trabalho é referente ao desenvolvimento de um calibrador multiobjetivo automático do modelo SWMM (Storm Water Management Model), e avaliação de algumas fontes de incertezas presentes no processo de calibração, visando à representação satisfatória da transformação chuva-vazão. O código foi escrito em linguagem C, e aplica os conceitos do método de otimização multiobjetivo NSGAII (Non Dominated Sorting Genetic Algorithm) com elitismo controlado, além de utilizar o código fonte do modelo SWMM para a determinação das vazões simuladas. Paralelamente, também foi criada uma interface visual, para melhorar a facilidade de utilização do calibrador. Os testes do calibrador foram aplicados a três sistemas diferentes: um sistema hipotético disponibilizado no pacote de instalação do SWMM; um sistema real de pequenas dimensões, denominado La Terraza, localizado no município de Sierra Vista, Arizona (EUA); e um sistema de maiores dimensões, a bacia hidrográfica do Córrego do Gregório, localizada no município de São Carlos (SP). Os resultados indicam que o calibrador construído apresenta, em geral, eficiência satisfatória, porém é bastante dependente da qualidade dos dados observados em campo e dos parâmetros de entrada escolhidos pelo usuário. Foi demonstrada a importância da escolha dos eventos utilizados na calibração, do estabelecimento de limites adequados nos valores das variáveis de decisão, da escolha das funções objetivo e, principalmente, da qualidade e representatividade dos dados de monitoramento pluvio e fluviométrico. Conclui-se que estes testes desenvolvidos contribuem para o entendimento mais aprofundado dos processos envolvidos na modelagem e calibração, possibilitando avanços na confiabilidade dos resultados da modelagem. / This project refers to the development of an automatic multi-objective calibrator for the SWMM (Storm Water Management Model), and the evaluation of some uncertainties sources inherent to the calibration process, aiming to a satisfactory rainfall-runoff transformation representation. The code was written in C language, and applies the concepts of the multi-objective optimization method NSGAII (Non Dominated Sorting Genetic Algorithm) with controlled elitism, using the source code of SWMM to calculate the simulated flow. In addition, a visual interface was also created to improve the calibrators usability. The calibrator tests were applied to three different systems: a hypothetical system available in the SWMM installation package; a real system of small dimensions, called La Terraza, located in the city of Sierra Vista, Arizona (USA); and a large dimensions system, the watershed of Gregório Stream, located in São Carlos (SP). The results indicate that the calibrator built presents, in general, satisfactory efficiency, although it is very dependent on the observed data quality and the input parameters selected by the user. The importance of the events chosen for calibration, the settlement of appropriate limits on the decision variables values, the objective functions choice, and especially the quality and representativeness of the rainfall and runoff monitoring data were demonstrated. We conclude that these performed tests contribute to the thorough understanding of the processes involved in modeling and calibration, enabling advances in the modeling results reliability.
9

Leitura automática de dispositivos mostradores analógicos de instrumentos de medição utilizando visão computacional. / Automatic reading of measurement devices analogical displays using computer vision.

Rynaldo Zanotele Hemerly de Almeida 22 May 2006 (has links)
Propõe-se um sistema de visão computacional para leitura automática de dispositivos mostradores analógicos de instrumentos de medição que não possuem interface de comunicação digital. Esse sistema pode ser aplicado na automação de processos de calibração desses instrumentos ou em outros ensaios em que sejam feitas leituras repetitivas por um operador humano. Espera-se reduzir o tempo de leitura e os custos envolvidos nos processos e alcançar exatidão e incerteza ao menos equivalentes aos da leitura humana. A abordagem proposta se baseia na comparação da inclinação do ponteiro com as inclinações das marcas de escala do dispositivo mostrador. Em uma primeira etapa realiza-se o reconhecimento das marcas de escala e a correspondência de cada marca a um valor de leitura a partir de três imagens capturadas e algumas informações consideradas conhecidas como o número de escalas, o número de marcas principais por escala e os valores associados a essas marcas principais. Em seguida parte-se para uma segunda etapa em que para cada nova imagem capturada é obtido um valor de leitura por meio da interpolação entre valores de inclinações calculados e os valores de leitura associados às marcas de escala. Uma análise de incerteza de leitura mostra que para os instrumentos estudados e equipamentos empregados (câmera e lentes) a leitura automática é compatível com a leitura humana e que a incerteza poderia ser eventualmente melhorada. Foram realizados diversos testes de leitura automática. Os resultados obtidos confirmaram as expectativas de incertezas e a ocorrência de erros mais significativos foi da ordem de apenas um por cento o que revela a robustez do método para utilização real. / A computer vision system for automatic reading of measurement devices analogical displays which do not have a digital communication interface is proposed. This system could be applied for the automation of these devices calibration processes or in other assays in which repetitive readings are done by man. It is expected a reduction in time spent and costs involved and an achievement of accuracy and uncertainty at least equivalent to those attained in human readings. The approach is based on the comparison between the pointer slope and the display device scale marks slope. In a first step the scale marks are identified and a reading value is attributed to each mark from three captured images and some assumed known data as the number of scales, the number of the main marks per scale and the corresponding values associated with these main marks. Then, in a second step, an reading value is attained to each new captured image through the interpolation between the calculated slopes figures and the associated marks reading values. An reading uncertainty analysis shows that considering the studied instruments and the employed devices (camera and lens) the automatic reading is consistent with the human reading and the uncertainty could be eventually improved. Several automatic reading tests were carried out. The results confirmed the expectations of uncertainties and the meaningful error rate was about only one per cent revealing the methods robustness to real application.
10

Calibração multiobjetivo do SWMM aplicada à transformação chuva-vazão / Multiobjective calibration of SWMM applied to rainfall-runoff transformation

Taís Arriero Shinma 24 May 2011 (has links)
Um calibrador automático multiobjetivo para o Storm Water Management Model (SWMM) foi desenvolvido utilizando o método de otimização multiobjetivo Non Dominated Sorting Genetic Algorithm (NSGA II) com elistismo controlado (Deb & Goel, 2001). O programa utiliza o código fonte do SWMM na etapa de avaliação das soluções, para determinar o valor das vazões simuladas, utilizado no cálculo das funções objetivo (FOs). Os testes do calibrador foram aplicados a dois sistemas diferentes, sendo o primeiro uma bacia exemplo hipotética disponibilizada no pacote de instalação do SWMM e o segundo a bacia do córrego do Gregório, localizada no município de São Carlos (SP). Foi realizada a análise de sensibilidade para os dois sistemas, visando determinar os parâmetros a serem calibrados. De modo geral, a porcentagem de áreas impermeáveis e os parâmetros de rugosidade e de infiltração apresentaram maior influência sobre a resposta do sistema em termos de vazão de pico e volume total escoado das bacias. O programa desenvolvido se mostrou eficiente para ambos os sistemas calibrados, com coeficientes de eficiência de Nash & Sutcliffe (1970) médios de 0,99 para a bacia exemplo e 0,87 para a bacia do córrego do Gregório, respectivamente, com um número reduzido de iterações. Construído o calibrador, testes foram realizados para identificar a melhor combinação de FOs e a abordagem multievento mais eficiente. Para tanto, foram testadas 55 diferentes combinações de FOs duas a duas. Os resultados evidenciaram que a melhor combinação testada foi a F2-F6, e a abordagem multievento mais eficiente foi a avaliação da médias das FOs, considerando todos os eventos utilizados na etapa de calibração. Cabe ressaltar que estas conclusões se aplicam somente ao sistema considerado neste estudo. Por fim, a validação comprovou a eficiência do calibrador, aplicada a 10 eventos distintos registrados na bacia do córrego do Gregório, com coeficiente de eficiência médio de 0,84. / An automatic multiobjective calibrator for the Storm Water Management Model (SWMM) was developed using the Non Dominated Sorting Genetic Algorithm (NSGA II) method with controlled elitism (Deb & Goel, 2001). The software uses the SWMM source code for evaluating the solutions, to determine the simulated flow values, used in the objective functions (OFs) calculation. The calibrator tests were applied on two different systems, a hypothetical example basin provided jointly to the SWMM installation package, and the basin of Gregório stream, located in São Carlos (SP). The sensitivity analysis was performed for both systems to determine the parameters to be calibrated. Generally, the percent of imperviousness, the roughness and infiltration parameters variations resulted in large modifications on the system response in terms of peak flow and total runoff volume. The developed software proved to be efficient for both calibrated systems, presenting an average of the Nash & Sutcliffe (1970) efficiency coeficient of 0.99 and 0.87 for the example basin and the Gregório stream basin, respectively, with a few number of iterations. After the calibrator built, tests were conducted aiming to identify the best OFs combination and the more efficient multievent approach. Thus, 55 different combinations in pairs of OFs were tested. The results showed that the best combination tested was the F2-F6 and most efficient multievent approach was the evaluation of the OFs means, considering all the calibration events. It is worth noting that these conclusions apply only to the system considered in this study. Finally, the validation confirmed the calibrator efficiency, applied to 10 different events recorded in the Gregório stream basin, presenting an average of the efficiency coeficient of 0.84.

Page generated in 0.1401 seconds