You searched for subject:(sensitivity analysis).
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Oregon State University
1.
Kennedy, Kenneth M.
Model Adaptivity and Numerical Solutions Using Sensitivity Analysis.
Degree: PhD, 2017, Oregon State University
URL: http://hdl.handle.net/1957/61398 
► In this work we consider the dependence of solutions to a partial differential equations system on its data. The problem of interest is a coupled…
(more)
▼ In this work we consider the dependence of solutions to a partial differential equations system on its data. The problem of interest is a coupled model of nonlinear flow and transport in porous media, with applications, e.g. to environmental modeling. The model of flow we consider is known as the non-Darcy model, and its solutions: the velocity, and pressure unknowns, depend on the coefficients of permeability and inertia, and other data such as boundary conditions. In turn, the transport solutions depend on the velocity of the fluid, and on boundary and initial conditions. Furthermore, one can be interested in a particular quantity computable from the flow and transport solutions, and represented by a functional. In this work we evaluate rigorously the
sensitivity, i.e., the derivative, of the solutions, or of the quantity of interest, upon the data.
Due to its delicate nature, the
sensitivity is evaluated either in a direct way, called Forward
Sensitivity, or via an adjoint method, which only uses a variational form. Our first contribution is that we find a way to find the
sensitivity for the coupled flow and transport model without having to solve multiple flow problems. Second, we prove the well-posedness of the flow problem, and set up the numerical approximation using the framework similar to that of expanded mixed finite element methods.
Next, the numerical approximation of the problem leads to a nonlinear system of discrete equations, which is difficult to solve. To aid in solving this system, we propose to take advantage of
sensitivity analysis, which is used in a novel way within a homotopy framework. The theoretical results in this thesis are illustrated with numerical simulations. The code, in Python, for the examples is provided.
Advisors/Committee Members: Peszynska, Malgorzata (advisor), Lee, John W. (committee member).
Subjects/Keywords: Sensitivity analysis
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APA (6th Edition):
Kennedy, K. M. (2017). Model Adaptivity and Numerical Solutions Using Sensitivity Analysis. (Doctoral Dissertation). Oregon State University. Retrieved from http://hdl.handle.net/1957/61398
Chicago Manual of Style (16th Edition):
Kennedy, Kenneth M. “Model Adaptivity and Numerical Solutions Using Sensitivity Analysis.” 2017. Doctoral Dissertation, Oregon State University. Accessed February 26, 2020.
http://hdl.handle.net/1957/61398.
MLA Handbook (7th Edition):
Kennedy, Kenneth M. “Model Adaptivity and Numerical Solutions Using Sensitivity Analysis.” 2017. Web. 26 Feb 2020.
Vancouver:
Kennedy KM. Model Adaptivity and Numerical Solutions Using Sensitivity Analysis. [Internet] [Doctoral dissertation]. Oregon State University; 2017. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1957/61398.
Council of Science Editors:
Kennedy KM. Model Adaptivity and Numerical Solutions Using Sensitivity Analysis. [Doctoral Dissertation]. Oregon State University; 2017. Available from: http://hdl.handle.net/1957/61398
Colorado School of Mines
2.
Ryken, Anna C.
Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction.
Degree: MS(M.S.), Geology and Geological Engineering, 2018, Colorado School of Mines
URL: http://hdl.handle.net/11124/172341
► The hydrology of high-elevation, mountainous regions is poorly represented in Earth Systems Models (ESMs). In addition to regulating downstream water delivery, these ecosystems play an…
(more)
▼ The hydrology of high-elevation, mountainous regions is poorly represented in Earth Systems Models (ESMs). In addition to regulating downstream water delivery, these ecosystems play an important role in the storage and land-atmosphere exchange of water. Water balances are sensitive to the amount of water stored in the snowpack (snow water equivalent, SWE), as much of Colorado’s water supply is derived from snowmelt. In an effort to resolve this hydrologic gap in ESMs, this study seeks to better understand how uncertainty in both model parameters and forcing affect simulated snow processes. To better understand parameter uncertainty and asses model performance, this study conducts a
sensitivity analysis, using active subspaces, on model inputs (meteorological forcing and static parameters) for both evergreen needleleaf and bare ground land cover types. Observations from an AmeriFlux tower at the Niwot Ridge research site are used to force an integrated single-column hydrologic model, ParFlow-CLM. This study found that trees can mute the effects of sublimation causing the evergreen needleleaf model to be sensitive primarily to hydrologic forcing; humidity in the winter, radiation and air temperature in the summer months. However, bare ground simulations were most sensitive to snow parameters along with radiation as these are unblocked by canopy. The bare ground model is most sensitive to overall changes to the linear combination of input parameters, which means radiation observations and snow parameterizations are of great importance for obtaining accurate hydrologic model results. Humidity measurements are also important, but the change in SWE of the evergreen needleleaf simulations was less than that of the bare ground simulations.
Advisors/Committee Members: Maxwell, Reed M. (advisor), Kroepsch, Adrianne (committee member), Singha, Kamini (committee member), Gochis, David (committee member).
Subjects/Keywords: Sensitivity analysis; Modeling
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APA (6th Edition):
Ryken, A. C. (2018). Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction. (Masters Thesis). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/172341
Chicago Manual of Style (16th Edition):
Ryken, Anna C. “Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction.” 2018. Masters Thesis, Colorado School of Mines. Accessed February 26, 2020.
http://hdl.handle.net/11124/172341.
MLA Handbook (7th Edition):
Ryken, Anna C. “Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction.” 2018. Web. 26 Feb 2020.
Vancouver:
Ryken AC. Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction. [Internet] [Masters thesis]. Colorado School of Mines; 2018. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/11124/172341.
Council of Science Editors:
Ryken AC. Sensitivity and model reduction of simulated snow processes : contrasting observational and parameter uncertainty to improve prediction. [Masters Thesis]. Colorado School of Mines; 2018. Available from: http://hdl.handle.net/11124/172341
Texas A&M University
3.
Hetzler, Adam C.
Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem.
Degree: 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/149343
► This research presents new physics-based methods to estimate predictive uncertainty stemming from uncertainty in the material opacities in radiative transfer computations of key quantities of…
(more)
▼ This research presents new physics-based methods to estimate predictive uncertainty stemming from uncertainty in the material opacities in radiative transfer computations of key quantities of interest (QOIs). New methods are needed because it is infeasible to apply standard uncertainty-propagation techniques to the O(105) uncertain opacities in a realistic simulation. The new approach toward uncertainty quantification applies the uncertainty
analysis to the physical parameters in the underlying model used to calculate the opacities. This set of uncertain parameters is much smaller (O(102)) than the number of opacities. To further reduce the dimension of the set of parameters to be rigorously explored, we use additional screening applied at two different levels of the calculational hierarchy: first, physics-based screening eliminates the physical parameters that are unimportant from underlying physics models a priori; then,
sensitivity analysis in simplified versions of the complex problem of interest screens out parameters that are not important to the QOIs. We employ a Bayesian Multivariate Adaptive Regression Spline (BMARS) emulator for this
sensitivity analysis. The high dimension of the input space and large number of samples test the efficacy of these methods on larger problems. Ultimately, we want to perform uncertainty quantification on the large, complex problem with the reduced set of parameters. Results of this research demonstrate that the QOIs for target problems agree at for different parameter screening criteria and varying sample sizes. Since the QOIs agree, we have gained confidence in our results using the multiple screening criteria and sample sizes.
Advisors/Committee Members: Adams, Marvin L (advisor), Mallick, Bani K (committee member), McClarren, Ryan G (committee member), Morel, Jim E (committee member).
Subjects/Keywords: Uncertainty Quantification; Sensitivity Analysis
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APA (6th Edition):
Hetzler, A. C. (2013). Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/149343
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Hetzler, Adam C. “Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem.” 2013. Thesis, Texas A&M University. Accessed February 26, 2020.
http://hdl.handle.net/1969.1/149343.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hetzler, Adam C. “Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem.” 2013. Web. 26 Feb 2020.
Vancouver:
Hetzler AC. Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem. [Internet] [Thesis]. Texas A&M University; 2013. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1969.1/149343.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hetzler AC. Quantification of Uncertainties Due to Opacities in a Laser-Driven Radiative-Shock Problem. [Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/149343
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of New Mexico
4.
Barboza, David R.
Sensitivity of Distress Rate to Observed Distress Levels.
Degree: Civil Engineering, 2016, University of New Mexico
URL: http://hdl.handle.net/1928/31657
► The New Mexico Department of Transportation (NMDOT) uses a composite pavement condition index to identify and rank roads for budgeting and scheduling repairs. NMDOT uses…
(more)
▼ The New Mexico Department of Transportation (NMDOT) uses a composite pavement condition index to identify and rank roads for budgeting and scheduling repairs. NMDOT uses an index number called the Pavement Serviceability Index or PSI. A key component of this index number is the Distress Rate (DR) which is comprised of pavement distress severities and extents with a weighting factor assigned for each distress. Until 2013, NMDOT conducted pavement evaluations manually and in 2012 revised how pavement distress data were collected and evaluated. The two pavement distress collection procedures that were altered the most were for transverse cracking and alligator cracking. This research evaluates how sensitive the DR is to the revised data collection procedures. The comparison used a single milepost test section and one evaluator as ground truth data and then varied input values for a single item while holding all of the others constant to see what sort of influence the data had on the DR. The results confirmed that the DR has limited
sensitivity due to the data ranges used for input to the composite DR index.
Advisors/Committee Members: Bogus Halter, Susan, Valentin, Vanessa, Zhang, Guohui.
Subjects/Keywords: Manual Pavement Evaluation Sensitivity Analysis
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APA (6th Edition):
Barboza, D. R. (2016). Sensitivity of Distress Rate to Observed Distress Levels. (Masters Thesis). University of New Mexico. Retrieved from http://hdl.handle.net/1928/31657
Chicago Manual of Style (16th Edition):
Barboza, David R. “Sensitivity of Distress Rate to Observed Distress Levels.” 2016. Masters Thesis, University of New Mexico. Accessed February 26, 2020.
http://hdl.handle.net/1928/31657.
MLA Handbook (7th Edition):
Barboza, David R. “Sensitivity of Distress Rate to Observed Distress Levels.” 2016. Web. 26 Feb 2020.
Vancouver:
Barboza DR. Sensitivity of Distress Rate to Observed Distress Levels. [Internet] [Masters thesis]. University of New Mexico; 2016. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1928/31657.
Council of Science Editors:
Barboza DR. Sensitivity of Distress Rate to Observed Distress Levels. [Masters Thesis]. University of New Mexico; 2016. Available from: http://hdl.handle.net/1928/31657
Humboldt State University
5.
Cunningham, Paul.
A sensitivity analysis of an individual-based trout model.
Degree: 2007, Humboldt State University
URL: http://hdl.handle.net/2148/183
► Individual-based models (IBMs) are a relatively new way to perform population modeling of a particular species. In this type of modeling, population level dynamics emerge…
(more)
▼ Individual-based models (IBMs) are a relatively new way to perform population modeling of a particular species. In this type of modeling, population level dynamics emerge as the result of actions of individuals, as members of the population make choices regarding habitat due to influence by environmental factors as well as competition from other members of the species.
There are very few, if any,
sensitivity analyses of individual-based ecological models reported in the literature. This is in part due to the recent advent of this type of modeling, as well as the overall complexity of the models themselves. The intention here is to demonstrate a method of analyzing an IBM so that relevant information is provided to the modeler regarding the strong and weak points of the model in the face of the
uncertainty in parameter values, while consuming a minimum of time and computational resources. In addition, this type of information will be useful to resource managers looking to support management decisions, as it will provide indications of how much confidence can be put into model output because the effects of parameter uncertainty on alternative management actions will be included in the ranking with regards to the efficacy of each proposed action. In this fashion, the model will aid resource managers to better understand the risk of making false predictions.
An individual-based model, inSTREAM v.4.05 (Railsback et al, 2004), was used to model a population of northern California coastal cutthroat trout in Little Jones Creek, a third order tributary of the Smith River in northern California. In this model, trout make daily habitat selection choices to maximize their fitness. The decision rules that govern these choices are influenced by the daily conditions within the modeled stream, various mortality risks, as well as factors concerning respiration, growth and reproduction. The uncertainty in 90 parameters of the model was analyzed.
Effects of parameter uncertainty were investigated in a three-phase process. The
first phase ranked the parameters based on a
sensitivity index which reflected how much the uncertainty in parameter value affected model output. In the second phase, the relative level of higher-order interactions amongst the parameters with the highest
sensitivity index was assessed. The third phase tested the robustness of model output, by varying all of the most sensitive parameters simultaneously, when evaluating proposed alterations to the watershed.
The model was found highly sensitive to some parameters, moderately sensitive to most, and not sensitive at all to a few. Although varying two high-
sensitivity parameters at a time did generally have a non-linear effect on model output, the model was able to reproduce the same population trends under multiple parameter perturbation as it did when only calibrated parameter settings were used.
Advisors/Committee Members: Lamberson, Roland H..
Subjects/Keywords: Sensitivity analysis
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APA (6th Edition):
Cunningham, P. (2007). A sensitivity analysis of an individual-based trout model. (Thesis). Humboldt State University. Retrieved from http://hdl.handle.net/2148/183
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Cunningham, Paul. “A sensitivity analysis of an individual-based trout model.” 2007. Thesis, Humboldt State University. Accessed February 26, 2020.
http://hdl.handle.net/2148/183.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Cunningham, Paul. “A sensitivity analysis of an individual-based trout model.” 2007. Web. 26 Feb 2020.
Vancouver:
Cunningham P. A sensitivity analysis of an individual-based trout model. [Internet] [Thesis]. Humboldt State University; 2007. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/2148/183.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Cunningham P. A sensitivity analysis of an individual-based trout model. [Thesis]. Humboldt State University; 2007. Available from: http://hdl.handle.net/2148/183
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Virginia Tech
6.
Munster, Drayton William.
Sensitivity Enhanced Model Reduction.
Degree: MS, Mathematics, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/23169
► In this study, we numerically explore methods of coupling sensitivity analysis to the reduced model in order to increase the accuracy of a proper orthogonal…
(more)
▼ In this study, we numerically explore methods of coupling
sensitivity analysis to the reduced model in order to increase the accuracy of a proper orthogonal decomposition (POD) basis across a wider range of parameters. Various techniques based on polynomial interpolation and basis alteration are compared. These techniques are performed on a 1-dimensional reaction-diffusion equation and 2-dimensional incompressible Navier-Stokes equations solved using the finite element method (FEM) as the full scale model. The expanded model formed by expanding the POD basis with the orthonormalized basis
sensitivity vectors achieves the best mixture of accuracy and computational efficiency among the methods compared.
Advisors/Committee Members: Zietsman, Lizette (committeechair), Borggaard, Jeffrey T. (committee member), Gugercin, Serkan (committee member).
Subjects/Keywords: Model Reduction; Sensitivity Analysis
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APA (6th Edition):
Munster, D. W. (2013). Sensitivity Enhanced Model Reduction. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/23169
Chicago Manual of Style (16th Edition):
Munster, Drayton William. “Sensitivity Enhanced Model Reduction.” 2013. Masters Thesis, Virginia Tech. Accessed February 26, 2020.
http://hdl.handle.net/10919/23169.
MLA Handbook (7th Edition):
Munster, Drayton William. “Sensitivity Enhanced Model Reduction.” 2013. Web. 26 Feb 2020.
Vancouver:
Munster DW. Sensitivity Enhanced Model Reduction. [Internet] [Masters thesis]. Virginia Tech; 2013. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10919/23169.
Council of Science Editors:
Munster DW. Sensitivity Enhanced Model Reduction. [Masters Thesis]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/23169
Virginia Tech
7.
Wei, Shiyi.
Practical Analysis of the Dynamic Characteristics of JavaScript.
Degree: PhD, Computer Science, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/56697
► JavaScript is a dynamic object-oriented programming language, which is designed with flexible programming mechanisms. JavaScript is widely used in developing sophisticated software systems, especially web…
(more)
▼ JavaScript is a dynamic object-oriented programming language, which is designed with flexible programming mechanisms. JavaScript is widely used in developing sophisticated software systems, especially web applications. Despite of its popularity, there is a lack of software tools that support JavaScript for software engineering clients. Dataflow
analysis approximates software behavior by analyzing the program code; it is the foundation for many software tools. However, several unique features of JavaScript render existing dataflow
analysis techniques ineffective.
Reflective constructs, generating code at runtime, make it difficult to acquire the complete program at compile time. Dynamic typing, resulting in changes in object behavior, poses a challenge for building accurate models of objects. Different functionalities can be observed when a function is variadic; the variance of the function behavior may be caused by the arguments whose values can only be known at runtime. Object constructors may be polymorphic such that objects created by the same constructor may contain different properties. In addition to object-oriented programming, JavaScript supports paradigms of functional and procedural programming; this feature renders dataflow
analysis techniques ineffective when a JavaScript application uses multiple paradigms. Dataflow
analysis needs to handle these challenges.
In this work, we present an
analysis framework and several dataflow analyses that can handle dynamic features in JavaScript. The first contribution of our work is the design and instantiation of the JavaScript Blended
Analysis Framework (JSBAF). This general-purpose and flexible framework judiciously combines dynamic and static analyses. We have implemented an instance of JSBAF, blended taint
analysis, to demonstrate the practicality of the framework.
Our second contribution is an novel context-sensitive points-to
analysis for JavaScript that accurately models object property changes. This algorithm uses a new program representation that enables partial flow-sensitive
analysis, a more accurate object representation, and an expanded points-to graph. We have defined parameterized state
sensitivity (i.e., k-state
sensitivity) and evaluated the effectiveness of 1-state-sensitive
analysis as the static phase of JSBAF.
The third contribution of our work is an adaptive context-sensitive
analysis that selectively applies context-sensitive
analysis on the function level. This two-staged adaptive
analysis extracts function characteristics from an inexpensive points-to
analysis and uses learning-based heuristics to decide on an appropriate context-sensitive
analysis per function. The experimental results show that the adaptive
analysis is more precise than any single context-sensitive
analysis for several programs in the benchmarks, especially for those multi-paradigm programs.
Advisors/Committee Members: Ryder, Barbara Gershon (committeechair), Hendren, Laurie J. (committee member), Kafura, Dennis G. (committee member), Yao, Danfeng (committee member), Tilevich, Eli (committee member).
Subjects/Keywords: Dataflow Analysis; JavaScript; Context Sensitivity
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APA (6th Edition):
Wei, S. (2015). Practical Analysis of the Dynamic Characteristics of JavaScript. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/56697
Chicago Manual of Style (16th Edition):
Wei, Shiyi. “Practical Analysis of the Dynamic Characteristics of JavaScript.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 26, 2020.
http://hdl.handle.net/10919/56697.
MLA Handbook (7th Edition):
Wei, Shiyi. “Practical Analysis of the Dynamic Characteristics of JavaScript.” 2015. Web. 26 Feb 2020.
Vancouver:
Wei S. Practical Analysis of the Dynamic Characteristics of JavaScript. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10919/56697.
Council of Science Editors:
Wei S. Practical Analysis of the Dynamic Characteristics of JavaScript. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/56697
Mississippi State University
8.
Jiang, Yi.
Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus.
Degree: PhD, Civil and Environmental Engineering, 2016, Mississippi State University
URL: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10262016-184604/
;
► Sensitivity analysis is essential for the hydrologic models to help gain insight into models behavior, and assess the model structure and conceptualization. Parameter estimation…
(more)
▼ Sensitivity analysis is essential for the hydrologic models to help gain insight into models behavior, and assess the model structure and conceptualization. Parameter estimation in the distributed hydrologic models is difficult due to the high-dimensional parameter spaces.
Sensitivity analysis identified the influential and non-influential parameters in the modeling process, thus it will benefit the calibration process.
This study identified, applied and evaluated two
sensitivity analysis methods for the APEX model. The screening methods, the Morris method, and LH-OAT method, were implemented in the experimental site in North Carolina for modeling runoff, sediment loss, TP and DP losses. At the beginning of the application, the run number evaluation was conducted for the Morris method. The result suggested that 2760 runs were sufficient for 45 input parameters to get reliable
sensitivity result.
Sensitivity result for the five management scenarios in the study site indicated that the Morris method and LH-OAT method provided similar results on the
sensitivity of the input parameters, except the difference on the importance of PARM2, PARM8, PARM12, PARM15, PARM20, PARM49, PARM76, PARM81, PARM84, and PARM85. The results for the five management scenarios indicated the very influential parameters were consistent in most cases, such as PARM23, PARM34, and PARM84. The sensitive parameters had good overlaps between different scenarios. In addition, little variation was observed in the importance of the sensitive parameters in the different scenarios, such as PARM26.
The optimization process with the most influential parameters from
sensitivity analysis showed great improvement on the APEX modeling performance in all scenarios by the objective functions, PI1, NSE, and GLUE.
Advisors/Committee Members: Dennis D. Truax (chair), John J. Ramirez-Avila (chair), Veera Gnaneswar Gude (committee member), James L. Martin (committee member).
Subjects/Keywords: APEX; Parameter optimization; Sensitivity analysis
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APA (6th Edition):
Jiang, Y. (2016). Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus. (Doctoral Dissertation). Mississippi State University. Retrieved from http://sun.library.msstate.edu/ETD-db/theses/available/etd-10262016-184604/ ;
Chicago Manual of Style (16th Edition):
Jiang, Yi. “Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus.” 2016. Doctoral Dissertation, Mississippi State University. Accessed February 26, 2020.
http://sun.library.msstate.edu/ETD-db/theses/available/etd-10262016-184604/ ;.
MLA Handbook (7th Edition):
Jiang, Yi. “Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus.” 2016. Web. 26 Feb 2020.
Vancouver:
Jiang Y. Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus. [Internet] [Doctoral dissertation]. Mississippi State University; 2016. [cited 2020 Feb 26].
Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10262016-184604/ ;.
Council of Science Editors:
Jiang Y. Sensitivity analysis and parameter estimation for the APEX model on runoff, sediments and phosphorus. [Doctoral Dissertation]. Mississippi State University; 2016. Available from: http://sun.library.msstate.edu/ETD-db/theses/available/etd-10262016-184604/ ;
Texas A&M University
9.
Amaya Ramirez, Bibian Helena.
Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release.
Degree: 2015, Texas A&M University
URL: http://hdl.handle.net/1969.1/155491
► Formaldehyde is widely used in the chemical industries as a raw material for resins, plastics, fertilizers, and polymers as a solvent, and a preservative. Due…
(more)
▼ Formaldehyde is widely used in the chemical industries as a raw material for resins, plastics, fertilizers, and polymers as a solvent, and a preservative. Due to its high reactivity, and acute toxicity, determining the possible consequences of accidental releases of formaldehyde in industries is critical for safety. Despite that, only limited risk
analysis work has been done.
In this work, we simulated the consequences of formaldehyde release for an industrial facility. The simulation were performed for two release scenarios, one of which was the worst-case scenario described in the Risk Management Plan (RMP) regulated by the Environmental Protection Agency (EPA), and the other was defined to account for a more probable situation in the industrial facility. The cloud dispersion of three different mixture of formaldehyde was simulated using PHAST, a software for consequence
analysis. The consequences were assessed for different atmospheric conditions, wind velocities and hole diameters.
The results show that, for the worst- case scenario, the largest downwind and crosswind distance is represented by stability class F and wind velocity 1.5 m/s. The behavior of the formaldehyde cloud confirms the positive influence of wind velocity on diluting effect.
The effect of direct influence of wind velocity and hole diameter were simulated for more probable scenarios. Simulations reveal that high wind velocities generally result in shorter impact distances. Except for the class D, where the wind velocity promotes the mass transfer of the liquid in the pool and the dispersion depends on pool dynamics, the downwind and crosswind distances increase when wind velocities are increased from 1.5m/s to 5m/s.
The
sensitivity analysis for the effect of hole diameter shows that the size of the hole compared to wind and stability class plays a more significant role on the dispersion of the formaldehyde.
Advisors/Committee Members: Mannan, M. Sam (advisor), Kravaris, Costas (committee member), Strzelec, Andrea (committee member).
Subjects/Keywords: Formaldehyde; consequence analysis; toxic material; sensitivity analysis
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APA (6th Edition):
Amaya Ramirez, B. H. (2015). Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/155491
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Amaya Ramirez, Bibian Helena. “Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release.” 2015. Thesis, Texas A&M University. Accessed February 26, 2020.
http://hdl.handle.net/1969.1/155491.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Amaya Ramirez, Bibian Helena. “Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release.” 2015. Web. 26 Feb 2020.
Vancouver:
Amaya Ramirez BH. Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release. [Internet] [Thesis]. Texas A&M University; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1969.1/155491.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Amaya Ramirez BH. Study of the Influence of the Main Input Parameters on Toxic Consequence Calculation for a Formaldehyde Release. [Thesis]. Texas A&M University; 2015. Available from: http://hdl.handle.net/1969.1/155491
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Colorado
10.
Zhou, Dingyu.
Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms.
Degree: PhD, Chemistry & Biochemistry, 2012, University of Colorado
URL: https://scholar.colorado.edu/chem_gradetds/84
► The use of theoretical kinetic modeling provides an invaluable tool for the study of biofuel blend development and optimization. These models provide a way…
(more)
▼ The use of theoretical kinetic modeling provides an invaluable tool for the study of biofuel blend development and optimization. These models provide a way to simulate complex combustion systems and extract information without the need for costly experimental procedures. Indeed, these models often allow one to treat extreme conditions, such as those found in combustion engines, where in situ experiment is not yet feasible. However, many combustion models have large uncertainties in their rate coefficients and many models have been optimized for just a few specific conditions. Therefore, systematic improvement of biofuel combustion models is often necessary. Since these models are quite large, for example the n-butanol combustion mechanism contains 1446 reactions and 243 species, a brute force improvement all rate constant parameters is practically impossible. My Ph.D. work involved applying a global
sensitivity analysis (GSA) method to combustion models of biofuel components in order to identify and improve the rate constants within the mechanisms that had the largest effect on the target simulation result. Specifically, my main focus was the combustion of n-butanol. GSA revealed that a target simulation result, the ignition time delay, was quite sensitive to self-reaction of the hydroperoxy radical HO2+HO2->H2O2+O2. The empirical rate coefficient for this reaction had a large uncertainty; therefore, high level ab initio calculations and transition state theory were used to calculate a more accurate rate coefficient for this reaction. The second part of my Ph.D. study involved developing an efficient method for determining the pathways taken during a chemical process using a stochastic method that followed ¡§single atoms¡¨. This study was motivated with the intent of extending the GSA method to account not only for the
sensitivity of simulation results to single reactions, but to entire chemical pathways. The method I developed extracts not only reaction flow within the chemical network, but specifies the probabilities of exact chemical pathways.
Advisors/Committee Members: Rex T. Skodje, Robert Parson, Joel Eaves, Veronica Vaida, J. Will Medlin.
Subjects/Keywords: Global Sensitivity Analysis; Stochastic Pathway Analysis; Chemistry
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APA (6th Edition):
Zhou, D. (2012). Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms. (Doctoral Dissertation). University of Colorado. Retrieved from https://scholar.colorado.edu/chem_gradetds/84
Chicago Manual of Style (16th Edition):
Zhou, Dingyu. “Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms.” 2012. Doctoral Dissertation, University of Colorado. Accessed February 26, 2020.
https://scholar.colorado.edu/chem_gradetds/84.
MLA Handbook (7th Edition):
Zhou, Dingyu. “Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms.” 2012. Web. 26 Feb 2020.
Vancouver:
Zhou D. Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms. [Internet] [Doctoral dissertation]. University of Colorado; 2012. [cited 2020 Feb 26].
Available from: https://scholar.colorado.edu/chem_gradetds/84.
Council of Science Editors:
Zhou D. Global Sensitivity and Stochastic Pathway Analysis of Chemical Mechanisms. [Doctoral Dissertation]. University of Colorado; 2012. Available from: https://scholar.colorado.edu/chem_gradetds/84
Colorado State University
11.
Lammers, Roderick William.
Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading.
Degree: MS(M.S.), Civil and Environmental Engineering, 2015, Colorado State University
URL: http://hdl.handle.net/10217/167090
► Eutrophication of aquatic ecosystems is one of the most pressing water quality concerns in the U.S. and around the world. Bank erosion has been largely…
(more)
▼ Eutrophication of aquatic ecosystems is one of the most pressing water quality concerns in the U.S. and around the world. Bank erosion has been largely overlooked as a source of nutrient loading, despite field studies demonstrating that this source can account for the majority of the total phosphorus budget of a watershed. Substantial effort has been made to develop mechanistic models to predict bank erosion and instability in stream systems; however, these models do not account for inherent natural variability in input values. Providing only single output values with no quantification of associated uncertainty can complicate management decisions focused on reducing bank erosion and nutrient loading to streams. To address this issue, uncertainty and
sensitivity analyses were performed on the Bank Stability and Toe Erosion Model (BSTEM), a mechanistic model developed by the USDA-ARS that simulates both mass wasting (stability) and fluvial erosion of streambanks.
Sensitivity analysis results indicate that variable influence on model output can vary depending on assumed input distributions. Generally, bank height, soil cohesion, and plant species were found to be most influential in determining stability of clay (cohesive) banks. In addition to these three inputs, groundwater elevation, stream stage, and bank angle were also identified as important in sand (non-cohesive) banks. Slope and bank height are the dominant variables in fluvial erosion modeling, while erodibility and critical shear stress are relatively unimportant. However, the threshold effect of critical shear stress (determining whether erosion occurs) was not explicitly accounted for, possibly explaining the relatively low
sensitivity indices for this variable. Model output distributions of sediment and phosphorus loading rates corresponded well to ranges published in the literature, helping validate both model performance and selected ranges of input values. In addition, a probabilistic modeling approach was applied to data from a watershed-scale sediment and phosphorus loading study on the Missisquoi River, Vermont to quantify uncertainty associated with these published results. While our estimates indicated that bank erosion was likely a significant source of sediment and phosphorus to the watershed in question, the uncertainty associated with these predictions indicates that they should probably be considered order of magnitude estimates only.
Advisors/Committee Members: Bledsoe, Brian P. (advisor), Baker, Daniel (committee member), Wohl, Ellen (committee member).
Subjects/Keywords: phosphorus; uncertainty analysis; sensitivity analysis; bank erosion
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MLA ·
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APA (6th Edition):
Lammers, R. W. (2015). Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/167090
Chicago Manual of Style (16th Edition):
Lammers, Roderick William. “Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading.” 2015. Masters Thesis, Colorado State University. Accessed February 26, 2020.
http://hdl.handle.net/10217/167090.
MLA Handbook (7th Edition):
Lammers, Roderick William. “Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading.” 2015. Web. 26 Feb 2020.
Vancouver:
Lammers RW. Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading. [Internet] [Masters thesis]. Colorado State University; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10217/167090.
Council of Science Editors:
Lammers RW. Uncertainty and sensitivity in a bank stability model: implications for estimating phosphorus loading. [Masters Thesis]. Colorado State University; 2015. Available from: http://hdl.handle.net/10217/167090
Loughborough University
12.
Wang, Mengchao.
Sensitivity analysis and evolutionary optimization for building design.
Degree: PhD, 2014, Loughborough University
URL: https://dspace.lboro.ac.uk/2134/16282
;
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631645
► In order to achieve global carbon reduction targets, buildings must be designed to be energy efficient. Building performance simulation methods, together with sensitivity analysis and…
(more)
▼ In order to achieve global carbon reduction targets, buildings must be designed to be energy efficient. Building performance simulation methods, together with sensitivity analysis and evolutionary optimization methods, can be used to generate design solution and performance information that can be used in identifying energy and cost efficient design solutions. Sensitivity analysis is used to identify the design variables that have the greatest impacts on the design objectives and constraints. Multi-objective evolutionary optimization is used to find a Pareto set of design solutions that optimize the conflicting design objectives while satisfying the design constraints; building design being an inherently multi-objective process. For instance, there is commonly a desire to minimise both the building energy demand and capital cost while maintaining thermal comfort. Sensitivity analysis has previously been coupled with a model-based optimization in order to reduce the computational effort of running a robust optimization and in order to provide an insight into the solution sensitivities in the neighbourhood of each optimum solution. However, there has been little research conducted to explore the extent to which the solutions found from a building design optimization can be used for a global or local sensitivity analysis, or the extent to which the local sensitivities differ from the global sensitivities. It has also been common for the sensitivity analysis to be conducted using continuous variables, whereas building optimization problems are more typically formulated using a mixture of discretized-continuous variables (with physical meaning) and categorical variables (without physical meaning). This thesis investigates three main questions; the form of global sensitivity analysis most appropriate for use with problems having mixed discretised-continuous and categorical variables; the extent to which samples taken from an optimization run can be used in a global sensitivity analysis, the optimization process causing these solutions to be biased; and the extent to which global and local sensitivities are different. The experiments conducted in this research are based on the mid-floor of a commercial office building having 5 zones, and which is located in Birmingham, UK. The optimization and sensitivity analysis problems are formulated with 16 design variables, including orientation, heating and cooling setpoints, window-to-wall ratios, start and stop time, and construction types. The design objectives are the minimisation of both energy demand and capital cost, with solution infeasibility being a function of occupant thermal comfort. It is concluded that a robust global sensitivity analysis can be achieved using stepwise regression with the use of bidirectional elimination, rank transformation of the variables and BIC (Bayesian information criterion). It is concluded that, when the optimization is based on a genetic algorithm, that solutions taken from the start of the optimization process can be reliably used in a…
Subjects/Keywords: 690; Sensitivity analysis; Global sensitivity analysis; Stepwise regression analysis; Local sensitivity analysis; Evolutionary optimization; Genetic algorithm; Building design; Building energy demand
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APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wang, M. (2014). Sensitivity analysis and evolutionary optimization for building design. (Doctoral Dissertation). Loughborough University. Retrieved from https://dspace.lboro.ac.uk/2134/16282 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631645
Chicago Manual of Style (16th Edition):
Wang, Mengchao. “Sensitivity analysis and evolutionary optimization for building design.” 2014. Doctoral Dissertation, Loughborough University. Accessed February 26, 2020.
https://dspace.lboro.ac.uk/2134/16282 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631645.
MLA Handbook (7th Edition):
Wang, Mengchao. “Sensitivity analysis and evolutionary optimization for building design.” 2014. Web. 26 Feb 2020.
Vancouver:
Wang M. Sensitivity analysis and evolutionary optimization for building design. [Internet] [Doctoral dissertation]. Loughborough University; 2014. [cited 2020 Feb 26].
Available from: https://dspace.lboro.ac.uk/2134/16282 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631645.
Council of Science Editors:
Wang M. Sensitivity analysis and evolutionary optimization for building design. [Doctoral Dissertation]. Loughborough University; 2014. Available from: https://dspace.lboro.ac.uk/2134/16282 ; http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.631645
Loughborough University
13.
Wang, Mengchao.
Sensitivity analysis and evolutionary optimization for building design.
Degree: PhD, 2014, Loughborough University
URL: http://hdl.handle.net/2134/16282
► In order to achieve global carbon reduction targets, buildings must be designed to be energy efficient. Building performance simulation methods, together with sensitivity analysis and…
(more)
▼ In order to achieve global carbon reduction targets, buildings must be designed to be energy efficient. Building performance simulation methods, together with sensitivity analysis and evolutionary optimization methods, can be used to generate design solution and performance information that can be used in identifying energy and cost efficient design solutions. Sensitivity analysis is used to identify the design variables that have the greatest impacts on the design objectives and constraints. Multi-objective evolutionary optimization is used to find a Pareto set of design solutions that optimize the conflicting design objectives while satisfying the design constraints; building design being an inherently multi-objective process. For instance, there is commonly a desire to minimise both the building energy demand and capital cost while maintaining thermal comfort. Sensitivity analysis has previously been coupled with a model-based optimization in order to reduce the computational effort of running a robust optimization and in order to provide an insight into the solution sensitivities in the neighbourhood of each optimum solution. However, there has been little research conducted to explore the extent to which the solutions found from a building design optimization can be used for a global or local sensitivity analysis, or the extent to which the local sensitivities differ from the global sensitivities. It has also been common for the sensitivity analysis to be conducted using continuous variables, whereas building optimization problems are more typically formulated using a mixture of discretized-continuous variables (with physical meaning) and categorical variables (without physical meaning). This thesis investigates three main questions; the form of global sensitivity analysis most appropriate for use with problems having mixed discretised-continuous and categorical variables; the extent to which samples taken from an optimization run can be used in a global sensitivity analysis, the optimization process causing these solutions to be biased; and the extent to which global and local sensitivities are different. The experiments conducted in this research are based on the mid-floor of a commercial office building having 5 zones, and which is located in Birmingham, UK. The optimization and sensitivity analysis problems are formulated with 16 design variables, including orientation, heating and cooling setpoints, window-to-wall ratios, start and stop time, and construction types. The design objectives are the minimisation of both energy demand and capital cost, with solution infeasibility being a function of occupant thermal comfort. It is concluded that a robust global sensitivity analysis can be achieved using stepwise regression with the use of bidirectional elimination, rank transformation of the variables and BIC (Bayesian information criterion). It is concluded that, when the optimization is based on a genetic algorithm, that solutions taken from the start of the optimization process can be reliably used in a…
Subjects/Keywords: 690; Sensitivity analysis; Global sensitivity analysis; Stepwise regression analysis; Local sensitivity analysis; Evolutionary optimization; Genetic algorithm; Building design; Building energy demand
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Record Details
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Wang, M. (2014). Sensitivity analysis and evolutionary optimization for building design. (Doctoral Dissertation). Loughborough University. Retrieved from http://hdl.handle.net/2134/16282
Chicago Manual of Style (16th Edition):
Wang, Mengchao. “Sensitivity analysis and evolutionary optimization for building design.” 2014. Doctoral Dissertation, Loughborough University. Accessed February 26, 2020.
http://hdl.handle.net/2134/16282.
MLA Handbook (7th Edition):
Wang, Mengchao. “Sensitivity analysis and evolutionary optimization for building design.” 2014. Web. 26 Feb 2020.
Vancouver:
Wang M. Sensitivity analysis and evolutionary optimization for building design. [Internet] [Doctoral dissertation]. Loughborough University; 2014. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/2134/16282.
Council of Science Editors:
Wang M. Sensitivity analysis and evolutionary optimization for building design. [Doctoral Dissertation]. Loughborough University; 2014. Available from: http://hdl.handle.net/2134/16282
Universiteit Utrecht
14.
Meekes, M.
Sensitivity to Evidence in Probabilistic Networks.
Degree: 2013, Universiteit Utrecht
URL: http://dspace.library.uu.nl:8080/handle/1874/286942
► The probabilistic network framework is an approach to apply probability theory to reasoning with uncertainty in knowledge-based systems. Whereas researchers have studied the properties of…
(more)
▼ The probabilistic network framework is an approach to apply probability theory to reasoning with uncertainty in knowledge-based systems. Whereas researchers have studied the properties of parameter
sensitivity analysis for probabilistic networks to quite some extent, evidence
sensitivity analysis has received far less attention. The aim of my thesis is to present new, fundamental insights on
sensitivity to evidence in probabilistic networks.
Advisors/Committee Members: Gaag, L. C. van der, Renooij, S..
Subjects/Keywords: bayesian networks; probabilistic networks; sensitivity analysis; probabilistic network pruning; evidence sensitivity set; evidence sensitivity function
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APA ·
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Manager
APA (6th Edition):
Meekes, M. (2013). Sensitivity to Evidence in Probabilistic Networks. (Masters Thesis). Universiteit Utrecht. Retrieved from http://dspace.library.uu.nl:8080/handle/1874/286942
Chicago Manual of Style (16th Edition):
Meekes, M. “Sensitivity to Evidence in Probabilistic Networks.” 2013. Masters Thesis, Universiteit Utrecht. Accessed February 26, 2020.
http://dspace.library.uu.nl:8080/handle/1874/286942.
MLA Handbook (7th Edition):
Meekes, M. “Sensitivity to Evidence in Probabilistic Networks.” 2013. Web. 26 Feb 2020.
Vancouver:
Meekes M. Sensitivity to Evidence in Probabilistic Networks. [Internet] [Masters thesis]. Universiteit Utrecht; 2013. [cited 2020 Feb 26].
Available from: http://dspace.library.uu.nl:8080/handle/1874/286942.
Council of Science Editors:
Meekes M. Sensitivity to Evidence in Probabilistic Networks. [Masters Thesis]. Universiteit Utrecht; 2013. Available from: http://dspace.library.uu.nl:8080/handle/1874/286942
East Tennessee State University
15.
Islam, Md Sajedul.
Matrix Dynamic Models for Structured Populations.
Degree: MS, Mathematical Sciences, 2019, East Tennessee State University
URL: https://dc.etsu.edu/etd/3645
► Matrix models are formulated to study the dynamics of the structured populations. We consider closed populations, that is, without migration, and populations with migration.…
(more)
▼ Matrix models are formulated to study the dynamics of the structured populations. We consider closed populations, that is, without migration, and populations with migration. The effects of specific patterns of migration, whether with constant or time-dependent terms, are explored within the context of how they manifest in model output, such as population size. Time functions, commonly known as relative sensitivities, are employed to rank the parameters of the models from most to least influential in the population size or abundance of individuals per group
Subjects/Keywords: matrix model; sensitivity analysis; sensitivity functions.; Dynamical Systems
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APA (6th Edition):
Islam, M. S. (2019). Matrix Dynamic Models for Structured Populations. (Thesis). East Tennessee State University. Retrieved from https://dc.etsu.edu/etd/3645
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Islam, Md Sajedul. “Matrix Dynamic Models for Structured Populations.” 2019. Thesis, East Tennessee State University. Accessed February 26, 2020.
https://dc.etsu.edu/etd/3645.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Islam, Md Sajedul. “Matrix Dynamic Models for Structured Populations.” 2019. Web. 26 Feb 2020.
Vancouver:
Islam MS. Matrix Dynamic Models for Structured Populations. [Internet] [Thesis]. East Tennessee State University; 2019. [cited 2020 Feb 26].
Available from: https://dc.etsu.edu/etd/3645.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Islam MS. Matrix Dynamic Models for Structured Populations. [Thesis]. East Tennessee State University; 2019. Available from: https://dc.etsu.edu/etd/3645
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Ontario Institute of Technology
16.
Boafo, Emmanuel.
Uncertainty quantification for safety verification applications in nuclear power plants.
Degree: 2016, University of Ontario Institute of Technology
URL: http://hdl.handle.net/10155/733
► There is an increasing interest in computational reactor safety analysis to systematically replace the conservative calculations by best estimate calculations augmented by quantitative uncertainty analysis…
(more)
▼ There is an increasing interest in computational reactor safety
analysis to systematically replace the conservative calculations by best estimate calculations augmented by quantitative uncertainty
analysis methods. This has been necessitated by recent regulatory requirements that have permitted the use of such methods in reactor safety
analysis. Stochastic uncertainty quantification methods have shown great promise, as they are better suited to capture the complexities in real engineering problems. This study proposes a framework for performing uncertainty quantification based on the stochastic approach, which can be applied to enhance safety
analysis.
Additionally, risk level has increased with the degradation of Nuclear Power Plant (NPP) equipment and instrumentation. In order to achieve NPP safety, it is important to continuously evaluate risk for all potential hazards and fault propagation scenarios and map protection layers to fault / failure / hazard propagation scenarios to be able to evaluate and verify safety level during NPP operation. In this study, the Fault Semantic Network (FSN) methodology is proposed. This involved the development of static and dynamic fault semantic network (FSN) to model possible fault propagation scenarios and the interrelationships among associated process variables. The proposed method was demonstrated by its application to two selected case studies. The use of FSN is essential for fault detection, understanding fault propagation scenarios and to aid in the prevention of catastrophic events.
Two transient scenarios were simulated with a best estimate thermal hydraulic code, CATHENA. Stochastic uncertainty quantification and
sensitivity analyses were performed using the OPENCOSSAN software which is based on the Monte Carlo method. The effect of uncertainty in input parameters were investigated by analyzing the probability distribution of output parameters. The first four moments (mean, variance, skewness and kurtosis) of the output parameters were computed and analyzed. The uncertainty in output pressure was 0.61% and 0.57% was found for the mass flow rate in the Edward???s blowdown transient. An uncertainty of 0.087% was obtained for output pressure and 0.048% for fuel pin temperature in the RD-14 test case. These results are expected to be useful for providing insight into safety margins related to safety
analysis and verification.
Advisors/Committee Members: Gaber, Hossam.
Subjects/Keywords: Uncertainty quantification; CATHENA; Sensitivity analysis; FSN; LOCA
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APA ·
Chicago ·
MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Boafo, E. (2016). Uncertainty quantification for safety verification applications in nuclear power plants. (Thesis). University of Ontario Institute of Technology. Retrieved from http://hdl.handle.net/10155/733
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Boafo, Emmanuel. “Uncertainty quantification for safety verification applications in nuclear power plants.” 2016. Thesis, University of Ontario Institute of Technology. Accessed February 26, 2020.
http://hdl.handle.net/10155/733.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Boafo, Emmanuel. “Uncertainty quantification for safety verification applications in nuclear power plants.” 2016. Web. 26 Feb 2020.
Vancouver:
Boafo E. Uncertainty quantification for safety verification applications in nuclear power plants. [Internet] [Thesis]. University of Ontario Institute of Technology; 2016. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10155/733.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Boafo E. Uncertainty quantification for safety verification applications in nuclear power plants. [Thesis]. University of Ontario Institute of Technology; 2016. Available from: http://hdl.handle.net/10155/733
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Texas A&M University
17.
Stripling, Hayes Franklin.
Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations.
Degree: 2013, Texas A&M University
URL: http://hdl.handle.net/1969.1/151312
► Depletion calculations for nuclear reactors model the dynamic coupling between the material composition and neutron flux and help predict reactor performance and safety characteristics. In…
(more)
▼ Depletion calculations for nuclear reactors model the dynamic coupling between the material composition and neutron flux and help predict reactor performance and safety characteristics. In order to be trusted as reliable predictive tools and inputs to licensing and operational decisions, the simulations must include an accurate and holistic quantification of errors and uncertainties in its outputs. Uncertainty quantification is a formidable challenge in large, realistic reactor models because of the large number of unknowns and myriad sources of uncertainty and error.
We present a framework for performing efficient uncertainty quantification in depletion problems using an adjoint approach, with emphasis on high-fidelity calculations using advanced massively parallel computing architectures. This approach calls for a solution to two systems of equations: (a) the forward, engineering system that models the reactor, and (b) the adjoint system, which is mathematically related to but different from the forward system. We use the solutions of these systems to produce
sensitivity and error estimates at a cost that does not grow rapidly with the number of uncertain inputs. We present the framework in a general fashion and apply it to both the source-driven and k-eigenvalue forms of the depletion equations. We describe the implementation and verification of solvers for the forward and ad- joint equations in the PDT code, and we test the algorithms on realistic reactor
analysis problems. We demonstrate a new approach for reducing the memory and I/O demands on the host machine, which can be overwhelming for typical adjoint algorithms. Our conclusion is that adjoint depletion calculations using full transport solutions are not only computationally tractable, they are the most attractive option for performing uncertainty quantification on high-fidelity reactor
analysis problems.
Advisors/Committee Members: Adams, Marvin L. (advisor), Mallick, Bani K. (committee member), McClarren, Ryan G. (committee member), Morel, Jim E. (committee member), Anitescu, Mihai (committee member).
Subjects/Keywords: Adjoint; Sensitivity Analysis; Uncertainty Quantification; Depletion Calculations
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APA (6th Edition):
Stripling, H. F. (2013). Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations. (Thesis). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/151312
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Stripling, Hayes Franklin. “Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations.” 2013. Thesis, Texas A&M University. Accessed February 26, 2020.
http://hdl.handle.net/1969.1/151312.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Stripling, Hayes Franklin. “Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations.” 2013. Web. 26 Feb 2020.
Vancouver:
Stripling HF. Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations. [Internet] [Thesis]. Texas A&M University; 2013. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1969.1/151312.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Stripling HF. Adjoint-Based Uncertainty Quantification and Sensitivity Analysis for Reactor Depletion Calculations. [Thesis]. Texas A&M University; 2013. Available from: http://hdl.handle.net/1969.1/151312
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Edinburgh
18.
Locatelli, Tommaso.
Developing and testing a model of wind damage risk for forest plantations in South-West Europe.
Degree: PhD, 2016, University of Edinburgh
URL: http://hdl.handle.net/1842/20386
► Wind is the main abiotic cause of disturbance to forests in large parts of the world, particularly at temperate and boreal latitudes. In the past…
(more)
▼ Wind is the main abiotic cause of disturbance to forests in large parts of the world, particularly at temperate and boreal latitudes. In the past few decades the consequences of large wind-induced losses have been experienced at various levels, from small forest owners to large-scale, whole-society level. This is particularly relevant for areas, such as Europe, where forests are intensively managed, and the assets exposed to wind hazard are substantial. To better manage forests and commercial tree plantations to reduce the risk of wind damage, process-based, semi-mechanistic mathematical models such as ForestGALES are used. This model has been parameterised and evaluated for numerous conifer species, which constitute the major plantation types in temperate and boreal biomes. However, the geographical extent and economic importance of fast-growing broadleaved species, such as those of the Eucalyptus genus, and the lack of detailed historical data on wind damage to these species, require that tools for the estimation of the risk of wind damage to these species are developed and evaluated. This is particularly relevant in light of the projected increases of surface temperature due to climate change, and of the frequency and severity of extreme windstorms, that are expected as a consequence of climate change. Fieldwork was conducted in a semi-natural Eucalyptus globulus (Labill.) forest in the Asturias region in Northern Spain to acquire data for the parameterisation of ForestGALES for E. globulus, using a tree-pulling experiment. The behaviour of the parameterisation was investigated for different stocking densities to evaluate whether the effects of tree height, stocking density, and presence of a fresh upwind gap are consistent with the literature. This parameterisation was then used to compare the vulnerability to wind damage between E. globulus and Pinus pinaster (Ait.), the predominant plantation species in the Aquitaine region of SW France where extensive damage was experienced from storms Martin (1999) and Klaus (2009). The effects of rooting depth (2x), growth rate (2x), presence/absence of a recently created windward gap, and of the predominant wind climate in Aquitaine were investigated in this comparison. In order to aid forest managers with optimal resource allocation for practical applications of ForestGALES, and to provide forest modellers with invaluable insights for the development of robust wind damage risk models, ForestGALES was subjected to a sensitivity analysis. A generalisation of the variance-based method of Sobol’ for the case of correlated variables was used to investigate the sensitivity of the outputs of ForestGALES (the critical wind speeds for stem breakage and uprooting, and the associated probabilities of damage) to variation in its input variables. Almost all the E. globulus trees pulled in Asturias failed by overturning rather than breakage, which allowed for good confidence in the calculations of the overturning moments required for the empirical component of ForestGALES. Resistance to…
Subjects/Keywords: 634.9; wind risk; ForestGALES; sensitivity analysis; Eucalyptus
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APA (6th Edition):
Locatelli, T. (2016). Developing and testing a model of wind damage risk for forest plantations in South-West Europe. (Doctoral Dissertation). University of Edinburgh. Retrieved from http://hdl.handle.net/1842/20386
Chicago Manual of Style (16th Edition):
Locatelli, Tommaso. “Developing and testing a model of wind damage risk for forest plantations in South-West Europe.” 2016. Doctoral Dissertation, University of Edinburgh. Accessed February 26, 2020.
http://hdl.handle.net/1842/20386.
MLA Handbook (7th Edition):
Locatelli, Tommaso. “Developing and testing a model of wind damage risk for forest plantations in South-West Europe.” 2016. Web. 26 Feb 2020.
Vancouver:
Locatelli T. Developing and testing a model of wind damage risk for forest plantations in South-West Europe. [Internet] [Doctoral dissertation]. University of Edinburgh; 2016. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/1842/20386.
Council of Science Editors:
Locatelli T. Developing and testing a model of wind damage risk for forest plantations in South-West Europe. [Doctoral Dissertation]. University of Edinburgh; 2016. Available from: http://hdl.handle.net/1842/20386
Addis Ababa University
19.
Jalele, Geletu.
Optimization of Hydropower Plant Expansion
.
Degree: 2008, Addis Ababa University
URL: http://etd.aau.edu.et/dspace/handle/123456789/4246
► This research is of a sequencing expansion problem in which capacity can be added only at discrete points in time. There is a forecast of…
(more)
▼ This research is of a sequencing expansion problem in which capacity can be added only at
discrete points in time. There is a forecast of demand in each period, and five expansion
projects each with a given capacity and cost.
Dynamic programming is used to determine the sequence of expansions necessary to provide
sufficient capacity to meet the demand in all periods at minimum discounted cost. The
alternative scenarios are represented with a tree structure.
This research also provides preliminary results for a discounted cash flow as well as a
dynamic programming solution.
Advisors/Committee Members: Dr. Zelalem Hailu, (advisor).
Subjects/Keywords: Capacity expansion;
dynamic programming;
sensitivity analysis
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APA (6th Edition):
Jalele, G. (2008). Optimization of Hydropower Plant Expansion
. (Thesis). Addis Ababa University. Retrieved from http://etd.aau.edu.et/dspace/handle/123456789/4246
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Jalele, Geletu. “Optimization of Hydropower Plant Expansion
.” 2008. Thesis, Addis Ababa University. Accessed February 26, 2020.
http://etd.aau.edu.et/dspace/handle/123456789/4246.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Jalele, Geletu. “Optimization of Hydropower Plant Expansion
.” 2008. Web. 26 Feb 2020.
Vancouver:
Jalele G. Optimization of Hydropower Plant Expansion
. [Internet] [Thesis]. Addis Ababa University; 2008. [cited 2020 Feb 26].
Available from: http://etd.aau.edu.et/dspace/handle/123456789/4246.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Jalele G. Optimization of Hydropower Plant Expansion
. [Thesis]. Addis Ababa University; 2008. Available from: http://etd.aau.edu.et/dspace/handle/123456789/4246
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Penn State University
20.
Kelleher, Christa Ann.
Interpreting hydrologic behavior in headwater streams using
comparative hydrology.
Degree: PhD, Civil Engineering, 2013, Penn State University
URL: https://etda.libraries.psu.edu/catalog/18807
► Headwater streams are the smallest streams within the river network, but cumulatively represent a large portion of stream length across the United States. While they…
(more)
▼ Headwater streams are the smallest streams within the
river network, but cumulatively represent a large portion of stream
length across the United States. While they are abundant, headwater
streams are typically unmonitored. As such, little is known about
how they will be impacted by climate and land use change. It is
widely regarded that environmental change, representing the
combined effects of changing land use and climate, is currently
altering many natural processes in landscapes across the globe, and
is expected to have significant impacts in headwater streams. There
is an urgent need to understand the sensitivity of headwater
streams to change, as well as the physical mechanisms that control
this change and how they vary across differences in climate,
vegetation, geology, and topography. Comparative hydrology, one
such approach, describes similarities and differences in catchment
behavior in terms of the evolution and current status of physical
setting. In this dissertation, we use comparisons across a range of
spatial and temporal scales to understand what physical
characteristics, represented by model parameters, most influence
model-predicted hydrologic behavior. In our first study, we apply
this framework to understand how dominant processes relate to
physical setting for the one-dimensional transport with inflow and
storage (OTIS) model, a transient storage model which is used to
characterize streams in terms of parameter values. We show that not
all parameters, representative of stream processes across a given
reach, may be able to be used in this characterization for all
streams. Additionally, we show that which parameters are sensitive,
and therefore viable to be used for stream reach characterization,
varies with physical setting across a single stream. In our second
and third studies, we use comparisons between headwater catchments
to understand how soil and vegetation properties influence
variability in hydrologic behavior. Sensitivity analysis is used in
conjunction with a distributed, physically-based watershed model,
used to simulate hydrologic behavior. In the second study, we
compare similarities and differences in controls on behavior for
five adjacent headwater catchments located in central Montana.
Similar catchment characteristics and properties control this
behavior at similar times across all of the basins. Differences in
parameter controls and our ability to explain this behavior are
attributed to variability in vegetation and geologic influence via
a fault that runs through the basin. In our last study, we compare
controls on behavior for four headwater catchments located in
different climates across the United States. We show variable
seasonality for periods when important parameters are sensitive
across different water balance components. Vegetation
characteristics are an important control on evapotranspiration and
snow water equivalent across all basins and streamflow for drier
basins. Soil characteristics largely governed variance in
streamflow, though which characteristics were…
Subjects/Keywords: hydrology; headwater streams; sensitivity analysis;
watersheds
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APA (6th Edition):
Kelleher, C. A. (2013). Interpreting hydrologic behavior in headwater streams using
comparative hydrology. (Doctoral Dissertation). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/18807
Chicago Manual of Style (16th Edition):
Kelleher, Christa Ann. “Interpreting hydrologic behavior in headwater streams using
comparative hydrology.” 2013. Doctoral Dissertation, Penn State University. Accessed February 26, 2020.
https://etda.libraries.psu.edu/catalog/18807.
MLA Handbook (7th Edition):
Kelleher, Christa Ann. “Interpreting hydrologic behavior in headwater streams using
comparative hydrology.” 2013. Web. 26 Feb 2020.
Vancouver:
Kelleher CA. Interpreting hydrologic behavior in headwater streams using
comparative hydrology. [Internet] [Doctoral dissertation]. Penn State University; 2013. [cited 2020 Feb 26].
Available from: https://etda.libraries.psu.edu/catalog/18807.
Council of Science Editors:
Kelleher CA. Interpreting hydrologic behavior in headwater streams using
comparative hydrology. [Doctoral Dissertation]. Penn State University; 2013. Available from: https://etda.libraries.psu.edu/catalog/18807
Penn State University
21.
Ayyala, Dinesh.
Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG.
Degree: MS, Civil Engineering, 2009, Penn State University
URL: https://etda.libraries.psu.edu/catalog/9579
► The Mechanistic-Empirical Pavement Design Guide (M-E PDG) was developed by the National Cooperative Highway Research Program to improve the design and performance of the national…
(more)
▼ The Mechanistic-Empirical Pavement Design Guide (M-E
PDG) was developed by the National Cooperative Highway Research
Program to improve the design and performance of the national
highway system. The design procedure used in the guide is a major
improvement over the previous design methods in terms of using
parameters related to construction and operation of a pavement to
predict the performance over a specified design life. These
parameters must be entered in the M-E PDG software as input, which
requires the user to gather a large amount of data. Therefore,
sensitivity study of the input parameters on a pavement’s predicted
performance is necessary for standardizing data collection and
documentation by a pavement design agency, as well as improving
pavement design with efficient utilization of resources to maximize
performance. Evaluation of currently followed design procedures by
the New England state agencies, evolution of a data collection
methodology for Level 2 and 3 design and study of sensitivity of
the collected data conforming to specified tolerances are conducted
as part of the research presented in this thesis.
Subjects/Keywords: MEPDG Sensitivity Study; MEPDG Statistical
Analysis
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Manager
APA (6th Edition):
Ayyala, D. (2009). Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG. (Masters Thesis). Penn State University. Retrieved from https://etda.libraries.psu.edu/catalog/9579
Chicago Manual of Style (16th Edition):
Ayyala, Dinesh. “Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG.” 2009. Masters Thesis, Penn State University. Accessed February 26, 2020.
https://etda.libraries.psu.edu/catalog/9579.
MLA Handbook (7th Edition):
Ayyala, Dinesh. “Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG.” 2009. Web. 26 Feb 2020.
Vancouver:
Ayyala D. Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG. [Internet] [Masters thesis]. Penn State University; 2009. [cited 2020 Feb 26].
Available from: https://etda.libraries.psu.edu/catalog/9579.
Council of Science Editors:
Ayyala D. Sensitivity Analysis of Pavement Performance Predicted using
the M-E PDG. [Masters Thesis]. Penn State University; 2009. Available from: https://etda.libraries.psu.edu/catalog/9579
Virginia Tech
22.
Corner, Sebastien Marc.
Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems.
Degree: PhD, Mechanical Engineering, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/82713
► This dissertation provides a complete mathematical framework to compute the sensitivities with respect to system parameters for any second order hybrid Ordinary Differential Equation (ODE)…
(more)
▼ This dissertation provides a complete mathematical framework to compute the sensitivities with respect to system parameters for any second order hybrid Ordinary Differential Equation (ODE) and rank 1 and 3 Differential Algebraic Equation (DAE) systems.
The hybrid system is characterized by discontinuities in the velocity state variables due to an impulsive forces at the time of event. At the time of event, such system may also exhibit a change in the equations of motion or in the kinematic constraints.
The analytical methodology that solves the sensitivities for hybrid systems is structured based on jumping conditions for both, the velocity state variables and the sensitivities matrix. The proposed analytical approach is then benchmarked against a known numerical method.
The mathematical framework is extended to compute sensitivities of the states of the model and of the general cost functionals with respect to model parameters for both, unconstrained and constrained, hybrid mechanical systems.
This dissertation emphasizes the penalty formulation for modeling constrained mechanical systems since this formalism has the advantage that it incorporates the kinematic constraints inside the equation of motion, thus easing the numerical integration, works well with redundant constraints, and avoids kinematic bifurcations.
In addition, this dissertation provides a unified mathematical framework for performing the direct and the adjoint
sensitivity analysis for general hybrid systems associated with general cost functions. The mathematical framework computes the jump
sensitivity matrix of the direct sensitivities which is found by computing the Jacobian of the jump conditions with respect to sensitivities right before the event. The main idea is then to obtain the transpose of the jump
sensitivity matrix to compute the jump conditions for the adjoint sensitivities.
Finally, the methodology developed obtains the
sensitivity matrix of cost functions with respect to parameters for general hybrid ODE systems. Such matrix is a key result for design
analysis as it provides the parameters that affect the given cost functions the most. Such results could be applied to gradient based algorithms, control optimization, implicit time integration methods, deep learning, etc.
Advisors/Committee Members: Sandu, Corina (committeechair), Sandu, Adrian (committeechair), Asbeck, Alan Thomas (committee member), Ben-Tzvi, Pinhas (committee member), Kurdila, Andrew J. (committee member).
Subjects/Keywords: Sensitivity analysis; Hybrid systems; Constrained systems
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APA (6th Edition):
Corner, S. M. (2018). Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/82713
Chicago Manual of Style (16th Edition):
Corner, Sebastien Marc. “Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems.” 2018. Doctoral Dissertation, Virginia Tech. Accessed February 26, 2020.
http://hdl.handle.net/10919/82713.
MLA Handbook (7th Edition):
Corner, Sebastien Marc. “Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems.” 2018. Web. 26 Feb 2020.
Vancouver:
Corner SM. Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems. [Internet] [Doctoral dissertation]. Virginia Tech; 2018. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10919/82713.
Council of Science Editors:
Corner SM. Modeling, Sensitivity Analysis, and Optimization of Hybrid, Constrained Mechanical Systems. [Doctoral Dissertation]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/82713
Virginia Tech
23.
Zhu, Yitao.
Sensitivity Analysis and Optimization of Multibody Systems.
Degree: PhD, Mechanical Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/71649
► Multibody dynamics simulations are currently widely accepted as valuable means for dynamic performance analysis of mechanical systems. The evolution of theoretical and computational aspects of…
(more)
▼ Multibody dynamics simulations are currently widely accepted as valuable means for dynamic performance
analysis of mechanical systems. The evolution of theoretical and computational aspects of the multibody dynamics discipline make it conducive these days for other types of applications, in addition to pure simulations. One very important such application is design optimization for multibody systems.
Sensitivity analysis of multibody system dynamics, which is performed before optimization or in parallel, is essential for optimization.
Current
sensitivity approaches have limitations in terms of efficiently performing
sensitivity analysis for complex systems with respect to multiple design parameters. Thus, we bring new contributions to the state-of-the-art in analytical
sensitivity approaches in this study. A direct differentiation method is developed for multibody dynamic models that employ Maggi's formulation. An adjoint variable method is developed for explicit and implicit first order Maggi's formulations, second order Maggi's formulation, and first and second order penalty formulations. The resulting sensitivities are employed to perform optimization of different multibody systems case studies. The collection of benchmark problems includes a five-bar mechanism, a full vehicle model, and a passive dynamic robot. The five-bar mechanism is used to test and validate the
sensitivity approaches derived in this paper by comparing them with other
sensitivity approaches. The full vehicle system is used to demonstrate the capability of the adjoint variable method based on the penalty formulation to perform
sensitivity analysis and optimization for large and complex multibody systems with respect to multiple design parameters with high efficiency.
In addition, a new multibody dynamics software library MBSVT (Multibody Systems at Virginia Tech) is developed in Fortran 2003, with forward kinematics and dynamics,
sensitivity analysis, and optimization capabilities. Several different contact and friction models, which can be used to model point contact and surface contact, are developed and included in MBSVT.
Finally, this study employs reference point coordinates and the penalty formulation to perform dynamic
analysis for the passive dynamic robot, simplifying the modeling stage and making the robotic system more stable. The passive dynamic robot is also used to test and validate all the point contact and surface contact models developed in MBSVT.
Advisors/Committee Members: Sandu, Adrian (committeechair), Sandu, Corina (committeechair), Southward, Steve C. (committee member), Dopico Dopico, Daniel (committee member), Bohn, Jan Helge (committee member).
Subjects/Keywords: Sensitivity Analysis; Optimization; Multibody Dynamics; Vehicle Dynamics
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APA (6th Edition):
Zhu, Y. (2015). Sensitivity Analysis and Optimization of Multibody Systems. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/71649
Chicago Manual of Style (16th Edition):
Zhu, Yitao. “Sensitivity Analysis and Optimization of Multibody Systems.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 26, 2020.
http://hdl.handle.net/10919/71649.
MLA Handbook (7th Edition):
Zhu, Yitao. “Sensitivity Analysis and Optimization of Multibody Systems.” 2015. Web. 26 Feb 2020.
Vancouver:
Zhu Y. Sensitivity Analysis and Optimization of Multibody Systems. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10919/71649.
Council of Science Editors:
Zhu Y. Sensitivity Analysis and Optimization of Multibody Systems. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/71649
Virginia Tech
24.
Hebbur Venkata Subba Rao, Vishwas.
Adjoint based solution and uncertainty quantification techniques for variational inverse problems.
Degree: PhD, Computer Science, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/76665
► Variational inverse problems integrate computational simulations of physical phenomena with physical measurements in an informational feedback control system. Control parameters of the computational model are…
(more)
▼ Variational inverse problems integrate computational simulations of physical phenomena with physical measurements in an informational feedback control system. Control parameters of the computational model are optimized such that the simulation results fit the physical measurements.The solution procedure is computationally expensive since it involves running the simulation computer model (the emph{forward model}) and the associated emph {adjoint model} multiple times. In practice, our knowledge of the underlying physics is incomplete and hence the associated computer model is laden with emph {model errors}. Similarly, it is not possible to measure the physical quantities exactly and hence the measurements are associated with emph {data errors}. The errors in data and model adversely affect the inference solutions. This work develops methods to address the challenges posed by the computational costs and by the impact of data and model errors in solving variational inverse problems.
Variational inverse problems of interest here are formulated as optimization problems constrained by partial differential equations (PDEs). The solution process requires multiple evaluations of the constraints, therefore multiple solutions of the associated PDE. To alleviate the computational costs we develop a parallel in time discretization algorithm based on a nonlinear optimization approach. Like in the emph{parareal} approach, the time interval is partitioned into subintervals, and local time integrations are carried out in parallel. Solution continuity equations across interval boundaries are added as constraints. All the computational steps - forward solutions, gradients, and Hessian-vector products - involve only ideally parallel computations and therefore are highly scalable.
This work develops a systematic mathematical framework to compute the impact of data and model errors on the solution to the variational inverse problems. The computational algorithm makes use of first and second order adjoints and provides an a-posteriori error estimate for a quantity of interest defined on the inverse solution (i.e., an aspect of the inverse solution). We illustrate the estimation algorithm on a shallow water model and on the Weather Research and Forecast model.
Presence of outliers in measurement data is common, and this negatively impacts the solution to variational inverse problems. The traditional approach, where the inverse problem is formulated as a minimization problem in L
2 norm, is especially sensitive to large data errors. To alleviate the impact of data outliers we propose to use robust norms such as the L
1 and Huber norm in data assimilation. This work develops a systematic mathematical framework to perform three and four dimensional variational data assimilation using L
1 and Huber norms. The power of this approach is demonstrated by solving data assimilation problems where measurements contain outliers.
Advisors/Committee Members: Sandu, Adrian (committeechair), Ribbens, Calvin J. (committee member), Constantinescu, Emil Mihai (committee member), De Sturler, Eric (committee member), Cao, Yang (committee member).
Subjects/Keywords: Data assimilation; Inverse problems; sensitivity analysis
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APA (6th Edition):
Hebbur Venkata Subba Rao, V. (2015). Adjoint based solution and uncertainty quantification techniques for variational inverse problems. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/76665
Chicago Manual of Style (16th Edition):
Hebbur Venkata Subba Rao, Vishwas. “Adjoint based solution and uncertainty quantification techniques for variational inverse problems.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 26, 2020.
http://hdl.handle.net/10919/76665.
MLA Handbook (7th Edition):
Hebbur Venkata Subba Rao, Vishwas. “Adjoint based solution and uncertainty quantification techniques for variational inverse problems.” 2015. Web. 26 Feb 2020.
Vancouver:
Hebbur Venkata Subba Rao V. Adjoint based solution and uncertainty quantification techniques for variational inverse problems. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10919/76665.
Council of Science Editors:
Hebbur Venkata Subba Rao V. Adjoint based solution and uncertainty quantification techniques for variational inverse problems. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/76665
University of Melbourne
25.
Zhu, Dan.
Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems.
Degree: 2016, University of Melbourne
URL: http://hdl.handle.net/11343/91770
► This thesis introduces new Monte-Carlo methods for sensitivity analysis in stochastic dynamical systems. Simulation is an efficient tool that provides solutions to problems with multi-dimensional…
(more)
▼ This thesis introduces new Monte-Carlo methods for sensitivity analysis in stochastic dynamical systems. Simulation is an efficient tool that provides solutions to problems with multi-dimensional stochastic set-ups. It is a method for propagating model inputs into model outputs through statistical sampling. Since the outputs inherently depend on the inputs, it is important to assess the impact of their changes, i.e. the derivatives of the output with respect to the model inputs. The ability to successfully perform derivative estimation via simulation is highly dependent on the mathematical design of the underlying program and the dimensionality of the problem. Accordingly, there is a need for the improved methods in this thesis.
In Chapter 3, we first present a new method to compute second-order sensitivities of financial products with discontinuous or angular payoffs by Monte Carlo simulation. The idea is to use a sequence of measure changes such that the limits’ dependence on the parameter of interest is eliminated. The methodology is optimal in terms of minimizing the variance of the likelihood ratio weight. Applications are presented for both equity options and interest-rate products with discontinuous payoff structures.
In Chapter 4, we consider a special class of exotic derivatives, i.e. products with early-exercise features. Given the exercise strategy, the pathwise angularities are removed by a sequence of measure changes. The first-order optimal partial proxy method is implemented to calculate the Hessians of Bermudan Swaptions and cancellable Swaps, the resulting pathwise estimates are unbiased and accurate.
The numerical schemes in Chapter 3 and 4 are determined by the discontinuities of the pathwise performance measure. That is the critical point where the performance measure passes the discontinuity. In Chapter 5, we address the issue of inexplicit critical points. Numerical techniques are used to approximate these points, and the bias introduced vanishes at the limit when computing first- and second-order derivatives.
While Chapter 3 and Chapter 4 address the issue associated with irregular payoff functions, we consider the irregularities of the underlying distribution in Chapter 6. We introduce new methods to computing first- and second-order sensitivities of functions simulated by rejection techniques. Measure changes are introduced to ensure the pathwise discontinuities in the acceptance-rejection decisions are removed. Applications are presented for computing Greeks of equity options with certain L evy-driven underlyings and to finding sensitivities of performance measures in queuing systems.
In Chapter 7, we use derivative estimation methods developed in previous chapters to determine the level of capital required to maintain a certain level of ruin probability. We first present a stratified sampling algorithm for estimating extremely small finite-time ruin probabilities. We further compute unbiased first- and second-order derivative estimates of the finite-time ruin…
Subjects/Keywords: Monte-Carlo; sensitivity analysis; Greeks, risk-management
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APA ·
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MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Zhu, D. (2016). Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/91770
Chicago Manual of Style (16th Edition):
Zhu, Dan. “Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems.” 2016. Doctoral Dissertation, University of Melbourne. Accessed February 26, 2020.
http://hdl.handle.net/11343/91770.
MLA Handbook (7th Edition):
Zhu, Dan. “Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems.” 2016. Web. 26 Feb 2020.
Vancouver:
Zhu D. Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems. [Internet] [Doctoral dissertation]. University of Melbourne; 2016. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/11343/91770.
Council of Science Editors:
Zhu D. Efficient and generic Monte-Carlo methods for computing sensitivities of stochastic systems. [Doctoral Dissertation]. University of Melbourne; 2016. Available from: http://hdl.handle.net/11343/91770
McMaster University
26.
Mostofian, Sara.
FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data.
Degree: MASc, 2014, McMaster University
URL: http://hdl.handle.net/11375/16028
► With an ever-increasing population both in Canada and globally, an improved quality of life will depend on having access to energy. The non-renewable, carbon-based, sources…
(more)
▼ With an ever-increasing population both in Canada and globally, an improved quality of life will depend on having access to energy. The non-renewable, carbon-based, sources of energy that presently provide a major amount of the world's energy supply are depleting and therefore will be expensive in the future. Nuclear technology is a relatively new technology which can fulfill future energy needs but requires highly specialized skills and knowledge to continue to make it safer, cleaner, more reliable, and more affordable. Thus the nuclear industry puts lots of efforts to develop and improve the next generation of nuclear power plants. The Supercritical Water Reactors (SCWRs) are one of the Generation IV nuclear-reactor systems.
The SCWRs, to a large extent, are very similar to light water reactors, but with a simpler design. The main advantage of SCWRs is their higher thermal efficiency. The Canadian SCWR has adopted an innovative fuel concept which is a mixture of plutonium and thorium oxides (Th, Pu) O2.
The role of nuclear data in fuel development and reactor-physics analysis is quite significant. With the development of nuclear data files over the years, nuclear cross sections and other parameters are widely available, but their accuracy is still a concern. Also the accuracy of nuclear data is more reliable for uranium-based fuels than for thorium-based fuels. It is not known how the uncertainties in the nuclear data will impact the fuel depletion in a SCWR. Thus a sensitivity analysis tool has been developed to evaluate the impact of uncertainties in the neutron cross-sections of the actinides present in SCWR fuel. This document provides the details on the theory and methodology used to develop this tool (FICST). The objective of this work is to develop a code, not any specific calculation done with it.
Thesis
Master of Applied Science (MASc)
Advisors/Committee Members: Buijs, Adriaan, Engineering Physics and Nuclear Engineering.
Subjects/Keywords: Tool for Sensitivity Analysis of SCWR
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APA (6th Edition):
Mostofian, S. (2014). FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data. (Masters Thesis). McMaster University. Retrieved from http://hdl.handle.net/11375/16028
Chicago Manual of Style (16th Edition):
Mostofian, Sara. “FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data.” 2014. Masters Thesis, McMaster University. Accessed February 26, 2020.
http://hdl.handle.net/11375/16028.
MLA Handbook (7th Edition):
Mostofian, Sara. “FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data.” 2014. Web. 26 Feb 2020.
Vancouver:
Mostofian S. FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data. [Internet] [Masters thesis]. McMaster University; 2014. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/11375/16028.
Council of Science Editors:
Mostofian S. FICST: A Tool for Sensitivity Analysis of SCWR Fuel Isotopic Composition to Nuclear Data. [Masters Thesis]. McMaster University; 2014. Available from: http://hdl.handle.net/11375/16028
University of Tennessee – Knoxville
27.
Zhou, Tong.
Slot-based Calling Context Encoding.
Degree: MS, Computer Science, 2018, University of Tennessee – Knoxville
URL: https://trace.tennessee.edu/utk_gradthes/5131
► Calling context is widely used in software engineering areas such as profiling, debugging and event logging. It can also enhance some dynamic analysis such as…
(more)
▼ Calling context is widely used in software engineering areas such as profiling, debugging and event logging. It can also enhance some dynamic
analysis such as data race detection. To obtain the calling context at runtime, current approaches either perform expensive stack walking to recover contexts or instrument the application and dynamically encode the context into an integer. The current encoding schemes are either not fully precise, or have high instrumentation and detection overhead, and scalability issue for large and highly recursive applications.We propose slot-based calling context encoding (SCCE), which consists of a scalable encoding for acyclic contexts and an efficient encoding for cyclic contexts. Evaluating with CPU 2006 benchmark suite, we show that our acyclic encoding is scalable, has very low instrumentation overhead, and an acceptable detection overhead. We also show that our cyclic encoding also has lower instrumentation and detection overhead than the state-of-the-art approach by significantly reducing the number of bytes pushed and checked for cyclic contexts.
Advisors/Committee Members: Michael R. Jantz, Micah Beck, James S. Plank.
Subjects/Keywords: calling context encoding; context sensitivity; program analysis
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APA ·
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MLA ·
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to Zotero / EndNote / Reference
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APA (6th Edition):
Zhou, T. (2018). Slot-based Calling Context Encoding. (Thesis). University of Tennessee – Knoxville. Retrieved from https://trace.tennessee.edu/utk_gradthes/5131
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Zhou, Tong. “Slot-based Calling Context Encoding.” 2018. Thesis, University of Tennessee – Knoxville. Accessed February 26, 2020.
https://trace.tennessee.edu/utk_gradthes/5131.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Zhou, Tong. “Slot-based Calling Context Encoding.” 2018. Web. 26 Feb 2020.
Vancouver:
Zhou T. Slot-based Calling Context Encoding. [Internet] [Thesis]. University of Tennessee – Knoxville; 2018. [cited 2020 Feb 26].
Available from: https://trace.tennessee.edu/utk_gradthes/5131.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Zhou T. Slot-based Calling Context Encoding. [Thesis]. University of Tennessee – Knoxville; 2018. Available from: https://trace.tennessee.edu/utk_gradthes/5131
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Colorado School of Mines
28.
Loudon, Tyson S.
Analysis and dynamic active subspaces for a long term model of HIV.
Degree: MS(M.S.), Applied Mathematics and Statistics, 2015, Colorado School of Mines
URL: http://hdl.handle.net/11124/20117
► The Human Immunodeficiency Virus (HIV) disables many components of the body's immune system and, without antiretroviral treatment, leads to the onset of Acquired Immune Deficiency…
(more)
▼ The Human Immunodeficiency Virus (HIV) disables many components of the body's immune system and, without antiretroviral treatment, leads to the onset of Acquired Immune Deficiency Syndrome (AIDS) and subsequently death. The infection progresses through three stages: initial or acute infection, an asymptomatic or latent period, and finally AIDS. Modeling the entire time course of HIV within the body can be difficult as many models have oversimplified its biological dynamics in the effort to gain mathematical insight but fail to capture the three stages of infection. Only one HIV model has been able to describe the entire time course of the infection, but this model is large and is expensive to simulate. In this paper, we'll show there are two viral free steady states and conduct a stability
analysis of one of the steady states. Then, we'll present a reduced order model for the T-cell count 1700 days after initial infection using active subspace methods. Building on the previous results, we'll create a global in time approximation of the T-cell count at any time using dynamic active subspaces.
Advisors/Committee Members: Pankavich, Stephen (advisor), Collis, Jon M. (committee member), Constantine, Paul G. (committee member).
Subjects/Keywords: HIV; Sensitivity Analysis; Math Modeling; Active Subspaces
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APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Loudon, T. S. (2015). Analysis and dynamic active subspaces for a long term model of HIV. (Masters Thesis). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/20117
Chicago Manual of Style (16th Edition):
Loudon, Tyson S. “Analysis and dynamic active subspaces for a long term model of HIV.” 2015. Masters Thesis, Colorado School of Mines. Accessed February 26, 2020.
http://hdl.handle.net/11124/20117.
MLA Handbook (7th Edition):
Loudon, Tyson S. “Analysis and dynamic active subspaces for a long term model of HIV.” 2015. Web. 26 Feb 2020.
Vancouver:
Loudon TS. Analysis and dynamic active subspaces for a long term model of HIV. [Internet] [Masters thesis]. Colorado School of Mines; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/11124/20117.
Council of Science Editors:
Loudon TS. Analysis and dynamic active subspaces for a long term model of HIV. [Masters Thesis]. Colorado School of Mines; 2015. Available from: http://hdl.handle.net/11124/20117
University of Waterloo
29.
Li, Chengbo.
Causal Sensitivity Analysis for Decision Trees.
Degree: 2015, University of Waterloo
URL: http://hdl.handle.net/10012/9076
► Ventilator assignments in the pediatric intensive care unit (PICU) are made by medical experts; however, for some patients the relationship between ventilator assignment and patient…
(more)
▼ Ventilator assignments in the pediatric intensive care unit (PICU) are made by medical experts; however, for some patients the relationship between ventilator assignment and patient health status is not well understood. Using observational data collected by Virtual PICU Systems (VPS) (58,772 PICU visits with covariates and different ventilator assignments conducted by clinicians), we attempt to identify which patients would derive the greatest clinical benefit from ventilators by providing a concise model to help clinicians estimate a ventilator's potential effect on individual patients, in the event that patients need to be prioritized due to limited ventilator availability.
Effectively allocating ventilators requires estimating the effect of ventilation on different patients; this is known as individual treatment effect estimation. However, we only have access to non-randomized data, which is confounded by the fact that sicker patients are more likely to be ventilated. In order to reduce bias due to potential confounding to estimate the average treatment effect, propensity score matching has been widely studied and applied to estimate the average treatment effect, which matches patients from treated group with patients from control group based on similar conditional probability of ventilator assignment given an individual patient's features. This matching process assumes no unmeasured confounding, meaning there must be no unobserved covariates influencing both treatment assignment and patient's outcome. However, this is not guaranteed to be true, and if it is not, the average treatment effect estimation using propensity score matching approach can be fragile given an unmeasured confounder with strong influences.
Rosenbaum and Dual Sensitivity Analysis is specifically designed for potential unmeasured confounder problems in propensity score matching, assuming confounder's existence it evaluates how "sensitive" the treatment effect estimation after matching can be. This sensitivity analysis method has been well-studied to evaluate the estimated average treatment effect based on propensity score matching, specifically, using generalized linear models as the propensity score model.
However, both estimating treatment effect via propensity score matching and its sensitivity analysis have their limitations: first, propensity score matching only helps in estimating the average treatment effect, while it does not provide much information about individual treatment effect on each patient; second, Rosenbaum and Dual Sensitivity Analysis only evaluates the robustness of estimated average treatment effect from propensity score matching, while it cannot evaluate the robustness of a complex model estimating the individual treatment effect, such as a decision tree model.
To solve this problem, we attempt to estimate the individual treatment effect from observational study, by proposing the treatment effect tree (TET) model. TET can be estimated through learning a Node-Level-Stabilizing decision tree based on matched…
Subjects/Keywords: Treatment Effect; Sensitivity Analysis; Decision Trees
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Li, C. (2015). Causal Sensitivity Analysis for Decision Trees. (Thesis). University of Waterloo. Retrieved from http://hdl.handle.net/10012/9076
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Chicago Manual of Style (16th Edition):
Li, Chengbo. “Causal Sensitivity Analysis for Decision Trees.” 2015. Thesis, University of Waterloo. Accessed February 26, 2020.
http://hdl.handle.net/10012/9076.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Li, Chengbo. “Causal Sensitivity Analysis for Decision Trees.” 2015. Web. 26 Feb 2020.
Vancouver:
Li C. Causal Sensitivity Analysis for Decision Trees. [Internet] [Thesis]. University of Waterloo; 2015. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10012/9076.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Li C. Causal Sensitivity Analysis for Decision Trees. [Thesis]. University of Waterloo; 2015. Available from: http://hdl.handle.net/10012/9076
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Universitat Politècnica de València
30.
Medici ., Chiara.
Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
.
Degree: 2010, Universitat Politècnica de València
URL: http://hdl.handle.net/10251/8428
► El conocimiento de los procesos hidrológicos es esencial para la gestión de los recursos hídricos tanto desde el punto de vista cuantitativo (crecidas o sequías)…
(more)
▼ El conocimiento de los procesos hidrológicos es esencial para la gestión de los recursos hídricos tanto desde el punto de vista cuantitativo (crecidas o sequías) como desde el punto de vista cualitativo (contaminación).
El funcionamiento hidrológico de las cuencas mediterráneas es aún bastante desconocido a pesar de los diferentes estudios realizados desde hace una veintena de años. Los progresos realizados en la identificación y modelización de los procesos hidrológicos corresponden casi en la totalidad a investigaciones realizadas en clima templado-húmedo (Bonell y Balek, 1993; Buttle, 1994). Esta falta de información, fuerza según Bonell (1993) a la "transferencia de resultados", a pesar de la necesidad evidente de desarrollar aproximaciones diferentes, principalmente en el ámbito de la modelización (Pilgrim et al. 1988).
Por lo que se refiere a la modelación hidrológica, los estudios disponibles (Durand et al., 1992; Parkin et al., 1996; Piñol et al., 1997 entre otros) muestran serias dificultades para reproducir las primeras crecidas de otoño, después del periodo estival seco. Para estas cuencas parece difícil modelizar correctamente uno o más años hidrológicos completos con un solo juego de parámetros (Piñol et al., 1997, Bernal et al., 2004).
El clima mediterráneo está caracterizado por una dinámica estacional muy marcada del régimen de precipitaciones y de la evapotranspiración, que favorece la alternancia durante el año de periodos secos y húmedos. Esto modifica fuertemente el estado hidrológico de la cuenca, de lo que deriva un comportamiento hidrológico complejo y no-lineal (Piñol et al. 1999).
La necesidad de comprender el funcionamiento hidrológico de un sistema responde a dos cuestiones importantes: por un lado es el procedimiento más indicado para proporcionar elementos útiles a la gestión integrada de los recursos hídricos y por otro lado es fundamental para la modelación del comportamiento de nutrientes por ejemplo como el nitrato.
Advisors/Committee Members: Martín Monerris, Miguel (advisor), Francés García, Félix Ramón (advisor), Wade, Andrew (advisor).
Subjects/Keywords: Hydrological modelling;
Sensitivity analysis;
Inorganic nitrogen
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❌
APA ·
Chicago ·
MLA ·
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CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Medici ., C. (2010). Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
. (Doctoral Dissertation). Universitat Politècnica de València. Retrieved from http://hdl.handle.net/10251/8428
Chicago Manual of Style (16th Edition):
Medici ., Chiara. “Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
.” 2010. Doctoral Dissertation, Universitat Politècnica de València. Accessed February 26, 2020.
http://hdl.handle.net/10251/8428.
MLA Handbook (7th Edition):
Medici ., Chiara. “Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
.” 2010. Web. 26 Feb 2020.
Vancouver:
Medici . C. Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
. [Internet] [Doctoral dissertation]. Universitat Politècnica de València; 2010. [cited 2020 Feb 26].
Available from: http://hdl.handle.net/10251/8428.
Council of Science Editors:
Medici . C. Progressive development of a hydrologic and inorganic nitrogen conceptual model to improve the understanding of small Mediterranean catchments behaviour
. [Doctoral Dissertation]. Universitat Politècnica de València; 2010. Available from: http://hdl.handle.net/10251/8428
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Open Access Theses and Dissertations