You searched for subject:(Computational efficiency).
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University of Utah
1.
DeMille, Robert Curtis.
Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail.
Degree: PhD, Chemistry, 2012, University of Utah
URL: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2028/rec/1656 
► A theoretical study of a chemical system is focused on representing the systemproperly with a model and using it to accurately represent and predict physical…
(more)
▼ A theoretical study of a chemical system is focused on representing the systemproperly with a model and using it to accurately represent and predict physical anddynamical properties of interest. The trade off between accuracy of simulations using atheoretical model and its computational expense is an important consideration inchoosing and implementing the model and accompanying force field. My research hassampled the two extremes of this balance. In developing the mW-Ion and mW/3SPNDNAmodels, a coarse-grained technique was used to simplify the interactions andsignificantly increase the efficiency of the calculations with respect to atomisticsimulations. These models have limited transferability to other studies due to theircoarseness, but reproduce properties such as solvation structure and ion dynamics quitewell, and this with the ability to extend the simulation studies to timescales intractable fortheir atomistic counterparts. In later work, while investigating potential improvements tosolid polymer electrolytes used in lithium battery technologies, an atomistic model with apolarizable force field was used in order to correctly capture the mobility of lithiumcations. This involved a considerably larger computational expense, but was necessary toretain fidelity to experimental data. The advantages and disadvantages of the two sidesof this balance is explored here, with detailed examination of the models and force fieldsused, their applicability, and broader impact in the simulation and scientific community.
Subjects/Keywords: Computational efficiency; DNA; Modeling; Molecular Dynamics
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APA (6th Edition):
DeMille, R. C. (2012). Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail. (Doctoral Dissertation). University of Utah. Retrieved from http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2028/rec/1656
Chicago Manual of Style (16th Edition):
DeMille, Robert Curtis. “Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail.” 2012. Doctoral Dissertation, University of Utah. Accessed January 23, 2021.
http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2028/rec/1656.
MLA Handbook (7th Edition):
DeMille, Robert Curtis. “Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail.” 2012. Web. 23 Jan 2021.
Vancouver:
DeMille RC. Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail. [Internet] [Doctoral dissertation]. University of Utah; 2012. [cited 2021 Jan 23].
Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2028/rec/1656.
Council of Science Editors:
DeMille RC. Multiple disciplinary modeling and reproduction of physical phenomena with computer simulations at high and low atomic detail. [Doctoral Dissertation]. University of Utah; 2012. Available from: http://content.lib.utah.edu/cdm/singleitem/collection/etd3/id/2028/rec/1656
Delft University of Technology
2.
Groen, J.P. (author).
Topology optimization using the Finite Cell Method.
Degree: 2015, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:ec565db0-3445-48c8-8059-0fad62aea7f7
► The ongoing demand for better performing designs, has resulted in an increase in the complexity of topology optimization problems. Traditionally, the majority of the corresponding…
(more)
▼ The ongoing demand for better performing designs, has resulted in an increase in the complexity of topology optimization problems. Traditionally, the majority of the corresponding computational cost comes from solving the analysis equations using linear finite elements (FE). In this thesis a topology optimization method is presented, that is based on the finite cell method (FCM). This higher-order fictitious domain method is, due to its decoupled geometry-, integration-, and analysis-mesh well suited for large-scale topology optimization, and reducing its corresponding computational cost. The use of a decoupled density and analysis mesh greatly reduced the computational cost of topology optimization compared to linear FEM. Especially in 3D topology optimization examples, the computational cost has been decreased by more than a factor 10, while maintaining a high-resolution in the density field. The use of a larger length-scale can reduce the computational cost even more, which is especially beneficial for robust topology optimization. It is identified that the choice of the analysis system completely depends on the complexity of the optimization problem. Simple optimization problems showed great increase in computational efficiency using relatively low polynomial degree (p= 1, 2, 3), combined with more density elements per finite cell. For more difficult topology optimization examples, such as problems were the boundary conditions have to be enforced in the weak sense, or stress-constrained topology optimization, a more accurate analysis system is required, hence a larger polynomial degree should be used.
Mechanics, Aerospace Structures & Materials
Aerospace Engineering
Advisors/Committee Members: Ruess, M. (mentor), Langelaar, M. (mentor).
Subjects/Keywords: topology optimization; finite cell method; computational efficiency
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APA (6th Edition):
Groen, J. P. (. (2015). Topology optimization using the Finite Cell Method. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:ec565db0-3445-48c8-8059-0fad62aea7f7
Chicago Manual of Style (16th Edition):
Groen, J P (author). “Topology optimization using the Finite Cell Method.” 2015. Masters Thesis, Delft University of Technology. Accessed January 23, 2021.
http://resolver.tudelft.nl/uuid:ec565db0-3445-48c8-8059-0fad62aea7f7.
MLA Handbook (7th Edition):
Groen, J P (author). “Topology optimization using the Finite Cell Method.” 2015. Web. 23 Jan 2021.
Vancouver:
Groen JP(. Topology optimization using the Finite Cell Method. [Internet] [Masters thesis]. Delft University of Technology; 2015. [cited 2021 Jan 23].
Available from: http://resolver.tudelft.nl/uuid:ec565db0-3445-48c8-8059-0fad62aea7f7.
Council of Science Editors:
Groen JP(. Topology optimization using the Finite Cell Method. [Masters Thesis]. Delft University of Technology; 2015. Available from: http://resolver.tudelft.nl/uuid:ec565db0-3445-48c8-8059-0fad62aea7f7
Texas A&M University
3.
Ghoreyshi, Seyedmostafa.
Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation.
Degree: PhD, Mechanical Engineering, 2018, Texas A&M University
URL: http://hdl.handle.net/1969.1/174302
► An Ultra-High Efficiency Gas Turbine (UHEGT) technology is developed in this study. In UHEGT, the combustion process is no longer contained in isolation between the…
(more)
▼ An Ultra-High
Efficiency Gas Turbine (UHEGT) technology is developed in this
study. In UHEGT, the combustion process is no longer contained in isolation between the
compressor and turbine, rather distributed in multiple stages and integrated within the
High-Pressure (HP)-turbine stator rows. Fundamental issues of aero-thermodynamic
design, combustion, and heat transfer are addressed in this study. The aero-thermodynamic
study shows that the UHEGT-concept improves the thermal
efficiency of gas turbines by
5-7% above the current most advanced gas turbine engines, such as Alstom GT24. The
designed thermodynamic cycle has a 45% thermal
efficiency and includes a six-stage
turbine with three stages of stator internal combustion. Meanline approach is used to
preliminary design the entire flow path in the turbine. Multiple configurations are designed
and simulated via
Computational Fluid Dynamics (CFD) to achieve the optimum
combustion system for UHEGT. Flow patterns, temperature distributions, secondary
losses, etc. are among the parameters studied in the results. The final configuration for the
combustion system includes two rows of injectors placed before the stator rows in the first
three turbine stages. The current injector configuration provides a highly uniform
temperature distribution at the rotor inlet, low pressure loss, and low emissions compared
to the other cases. Different approaches are numerically studied to lower the stator blade
surface temperature distribution in UHEGT from which indexing (clocking) is shown to
be very effective.
In the final part of this study, a dynamic simulation is performed on the entire engine
using the nonlinear generic code GETRAN developed by Schobeiri. The simulations are in
2D (space-time) and include the complete gas turbine engine. The system performance is
studied under variable design and off-design conditions. The results show that most of the
system parameters fluctuate with similar patterns to the fuel schedule. However, the
amplitudes of the fluctuations are different and there is a time lag in the response profiles
relative to the fuel schedules. It is shown that thermal
efficiency variations are smaller
compared to the other parameters which means the system performs in efficiencies close to
the design point throughout the entire cycle.
Advisors/Committee Members: Schobeiri, Meinhard Taher (advisor), Reddy, J.N. (committee member), Palazzolo , Alan (committee member), Guermond, Jean-Luc (committee member).
Subjects/Keywords: Gas Turbine; Efficiency; Computational Fluid Dynamics; Combustion; Dynamic Operation
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APA (6th Edition):
Ghoreyshi, S. (2018). Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation. (Doctoral Dissertation). Texas A&M University. Retrieved from http://hdl.handle.net/1969.1/174302
Chicago Manual of Style (16th Edition):
Ghoreyshi, Seyedmostafa. “Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation.” 2018. Doctoral Dissertation, Texas A&M University. Accessed January 23, 2021.
http://hdl.handle.net/1969.1/174302.
MLA Handbook (7th Edition):
Ghoreyshi, Seyedmostafa. “Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation.” 2018. Web. 23 Jan 2021.
Vancouver:
Ghoreyshi S. Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation. [Internet] [Doctoral dissertation]. Texas A&M University; 2018. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1969.1/174302.
Council of Science Editors:
Ghoreyshi S. Development of an Ultra-High Efficiency Gas Turbine Engine (UHEGT) with Stator Internal Combustion: Design, Off-Design, and Nonlinear Dynamic Operation. [Doctoral Dissertation]. Texas A&M University; 2018. Available from: http://hdl.handle.net/1969.1/174302
University of Guelph
4.
Dobbs, Angie.
Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models.
Degree: MS, Department of Mathematics and Statistics, 2012, University of Guelph
URL: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3248
► Individual-level models (ILMs) are models that can use the spatial-temporal nature of disease data to capture the disease dynamics. Parameter estimation is usually done via…
(more)
▼ Individual-level models (ILMs) are models that can use the spatial-temporal nature of disease data to capture the disease dynamics. Parameter estimation is usually done via Markov chain Monte Carlo (MCMC) methods, but correlation between model parameters negatively affects MCMC mixing. Introducing a normalization constant to alleviate the correlation results in MCMC convergence over fewer iterations, however this negatively effects computation time. It is important that model fitting is done as efficiently as possible. An upper-truncated distance kernel is introduced to quicken the computation of the likelihood, but this causes a loss in goodness-of-fit. The normalization constant and upper-truncated distance kernel are evaluated as components in various ILMs via a simulation study. The normalization constant is seen not to be worthwhile, as the effect of increased computation time is not outweighed by the reduced correlation. The upper-truncated distance kernel reduces computation time but worsens model fit as the truncation distance decreases.
Advisors/Committee Members: Deardon, Rob (advisor).
Subjects/Keywords: epidemic models; Markov chain Monte Carlo; Bayesian inference; computational efficiency; normalization
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APA (6th Edition):
Dobbs, A. (2012). Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models. (Masters Thesis). University of Guelph. Retrieved from https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3248
Chicago Manual of Style (16th Edition):
Dobbs, Angie. “Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models.” 2012. Masters Thesis, University of Guelph. Accessed January 23, 2021.
https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3248.
MLA Handbook (7th Edition):
Dobbs, Angie. “Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models.” 2012. Web. 23 Jan 2021.
Vancouver:
Dobbs A. Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models. [Internet] [Masters thesis]. University of Guelph; 2012. [cited 2021 Jan 23].
Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3248.
Council of Science Editors:
Dobbs A. Issues of Computational Efficiency and Model Approximation for Spatial Individual-Level Infectious Disease Models. [Masters Thesis]. University of Guelph; 2012. Available from: https://atrium.lib.uoguelph.ca/xmlui/handle/10214/3248
University of Illinois – Urbana-Champaign
5.
Kim, Soobae.
Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability.
Degree: PhD, 1200, 2014, University of Illinois – Urbana-Champaign
URL: http://hdl.handle.net/2142/50704
► As modern power systems have been operated closer to their security limits, the importance of their static and dynamic security assessments is increasing. However, due…
(more)
▼ As modern power systems have been operated closer to their security limits, the importance of their static and dynamic security assessments is increasing. However, due to the large-scale nature of an interconnected power system and
the nonlinear characteristics of power system equations,
computational limits impose severe constraints for such security assessments. It is thus critically
important to develop rapid and precise power system analysis tools, which are fundamental for the security evaluations.
In this dissertation, comprehensive approaches to both reduce the
computational requirements and to achieve a high level of simulation accuracy are examined for application to power system steady-state solutions and transient stability analyses. Three approaches are proposed and validated, which are a mixed power-flow analysis, a mixed transient stability analysis, and an exciter model complexity reduction.
The first approach, a mixed power-flow analysis, focuses on reducing the
computational complexity of the steady-state solution. The approach combines ac and dc power flow models to decrease the number of required computations while still capturing variations in the external system. A high level of accuracy in the targeted central part of the system is achieved using the detailed ac model. The less detailed dc model is used for the external system to reduce
computational requirements without neglecting it altogether.
In the second approach, the mixed power-flow analysis is extended to transient stability analysis. This method reduces
computational requirements for power system transient stability simulation while retaining important dynamic information. In order to prevent the loss of simulation accuracy, the real power losses ignored by the standard dc model are compensated for in the external system.
Finally, the exciter model complexity reduction approach is presented for further improved transient stability analysis. This topic investigates conditions in which fast modes of the exciter model can be neglected or must
be preserved. When the fast modes can be ignored, a simpler model with those modes removed replaces an original model and simulation steps can be increased without numerical stability issues. During a transient simulation, the proposed method switches dynamically between the original model and the reduced model, depending on the switching criterion presented.
Advisors/Committee Members: Overbye, Thomas J. (advisor), Overbye, Thomas J. (Committee Chair), Sauer, Peter W. (committee member), Chen, Deming (committee member), Domínguez-García, Alejandro D. (committee member), Zhu, Hao (committee member), Davis, Katherine (committee member).
Subjects/Keywords: Power system analysis; Power-flow; Transient Stability; Computational efficiency
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APA (6th Edition):
Kim, S. (2014). Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability. (Doctoral Dissertation). University of Illinois – Urbana-Champaign. Retrieved from http://hdl.handle.net/2142/50704
Chicago Manual of Style (16th Edition):
Kim, Soobae. “Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability.” 2014. Doctoral Dissertation, University of Illinois – Urbana-Champaign. Accessed January 23, 2021.
http://hdl.handle.net/2142/50704.
MLA Handbook (7th Edition):
Kim, Soobae. “Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability.” 2014. Web. 23 Jan 2021.
Vancouver:
Kim S. Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability. [Internet] [Doctoral dissertation]. University of Illinois – Urbana-Champaign; 2014. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/2142/50704.
Council of Science Editors:
Kim S. Power system analysis criteria-based computational efficiency enhancement for power flow and transient stability. [Doctoral Dissertation]. University of Illinois – Urbana-Champaign; 2014. Available from: http://hdl.handle.net/2142/50704
6.
Ehsaei, Maryam.
Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures.
Degree: PhD, Civil/Environmental Engineering, 2019, Old Dominion University
URL: 9781392421819
;
https://digitalcommons.odu.edu/cee_etds/102
► Serial Jacobi transformation algorithm for the solution of “standard eigen-problems” is re-visited to facilitate the explanation of the proposed parallel transformation algorithm, for which…
(more)
▼ Serial Jacobi transformation algorithm for the solution of “standard eigen-problems” is re-visited to facilitate the explanation of the proposed parallel transformation algorithm, for which
computational efficiency can be realized in this study through “pattern recognition” for the development and explanation of “explicit formulas” to avoid costly matrix time matrix operations. The proposed parallel Jacobi transformation for the solution of “generalized eigen-problems” has also been incorporated into the “improved damage detection” algorithm.
Computational efficiency and robust behaviors for the entire proposed procedures (eigen-solution, damage detection and damage quantification) can be validated through several academic and real-life numerical examples. Numerical results obtained from this study have indicated that our proposed generalized Jacobi transformation is more robust/reliable as compared to MATLAB eigen-solver. Furthermore, our proposed simple rule of thumb for damage detection of aging bridge structures also give better results than existing algorithms.
Advisors/Committee Members: Duc T. Nguyen, Gene Hou, Yunbyeong Chae, Mojtaba Sirjani.
Subjects/Keywords: Serial Jacobi transformation algorithm; Eigen-problems; Computational efficiency; Civil Engineering
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APA (6th Edition):
Ehsaei, M. (2019). Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures. (Doctoral Dissertation). Old Dominion University. Retrieved from 9781392421819 ; https://digitalcommons.odu.edu/cee_etds/102
Chicago Manual of Style (16th Edition):
Ehsaei, Maryam. “Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures.” 2019. Doctoral Dissertation, Old Dominion University. Accessed January 23, 2021.
9781392421819 ; https://digitalcommons.odu.edu/cee_etds/102.
MLA Handbook (7th Edition):
Ehsaei, Maryam. “Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures.” 2019. Web. 23 Jan 2021.
Vancouver:
Ehsaei M. Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures. [Internet] [Doctoral dissertation]. Old Dominion University; 2019. [cited 2021 Jan 23].
Available from: 9781392421819 ; https://digitalcommons.odu.edu/cee_etds/102.
Council of Science Editors:
Ehsaei M. Parallel Jacobi Transformation Algorithm for Generalized Eigen-Solution With Improved Damage Detection of Truss/Bridge-Type Structures. [Doctoral Dissertation]. Old Dominion University; 2019. Available from: 9781392421819 ; https://digitalcommons.odu.edu/cee_etds/102
Colorado School of Mines
7.
Simonson, Peter.
Computationally efficient methods for block average models.
Degree: PhD, Applied Mathematics and Statistics, 2020, Colorado School of Mines
URL: http://hdl.handle.net/11124/174205
► In many applications, spatial data are typically collected at areal levels (i.e., block data), while inferences and predictions are desired about the variable at points…
(more)
▼ In many applications, spatial data are typically collected at areal levels (i.e., block data), while inferences and predictions are desired about the variable at points or blocks different from those at which the variable has been observed. These inferences and predictions typically depend on integrals of the moment functions of an underlying continuous spatial process. These integrals are often analytically intractable, and numerically expensive to approximate to high levels of accuracy. In this dissertation I describe a method based on Fourier transforms by which multiple integrals of covariance functions over irregular data regions may be numerically approximated with the same level of accuracy as traditional methods, but at a greatly reduced
computational expense. This method also provides convenient values used in spatial prediction. Examples are provided that demonstrate the accuracy and speed of the method in both simulation and real data contexts. Additionally, I examine a model misspecification used with block average observations that avoids expensive covariance integrals. I assess the extent to which both the block design and underlying process properties can affect the accuracy and stability of estimation and prediction tasks performed using this misspecification (relative to when these tasks are performed using a correctly specified observational model), and provide guidance for practitioners as to when this misspecification is inappropriate. Finally, as classic geostatistical approaches (both in point-referenced and block average contexts) do not scale well to big data problems (largely due to costly matrix inversion calculations), several alternative Gaussian process models have been developed for use with big point-referenced data. I describe and demonstrate the adaption of one such model for use with big block average data.
Advisors/Committee Members: Bandyopadhyay, Soutir (advisor), Nychka, Douglas (advisor), Newman, Alexandra M. (committee member), Tenorio, Luis (committee member), Navidi, William Cyrus (committee member).
Subjects/Keywords: computational efficiency; spatial statistics; Fourier transforms; block average models
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APA ·
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APA (6th Edition):
Simonson, P. (2020). Computationally efficient methods for block average models. (Doctoral Dissertation). Colorado School of Mines. Retrieved from http://hdl.handle.net/11124/174205
Chicago Manual of Style (16th Edition):
Simonson, Peter. “Computationally efficient methods for block average models.” 2020. Doctoral Dissertation, Colorado School of Mines. Accessed January 23, 2021.
http://hdl.handle.net/11124/174205.
MLA Handbook (7th Edition):
Simonson, Peter. “Computationally efficient methods for block average models.” 2020. Web. 23 Jan 2021.
Vancouver:
Simonson P. Computationally efficient methods for block average models. [Internet] [Doctoral dissertation]. Colorado School of Mines; 2020. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/11124/174205.
Council of Science Editors:
Simonson P. Computationally efficient methods for block average models. [Doctoral Dissertation]. Colorado School of Mines; 2020. Available from: http://hdl.handle.net/11124/174205
Delft University of Technology
8.
Fumagalli, Andrea (author).
Energy Space Layout: Designing space layout with optimised energy performance.
Degree: 2020, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:117335ea-4c43-4796-9ad7-d580403fcb35
► The current housing market in the Netherlands depicts a need for energy-efficient buildings for young professionals. Performative Computational Architecture (PCA), as computational methodology, is a…
(more)
▼ The current housing market in the Netherlands depicts a need for energy-efficient buildings for young professionals. Performative Computational Architecture (PCA), as computational methodology, is a valuable source of knowledge and design support to integrate the buildings’ performances at early stages. By applying PCA, this thesis explores and optimises the correlation between space layout and energy performance of a co-living residence in the Netherlands. Firstly, a generic model is developed to gain initial findings, then, is applied to a case-study to evaluate its practicability. The study considers a mixed-mode building with adaptive thermal comfort models and optimises three objectives distinctively: the cooling, the heating and the lighting demands. The results provide both computational and energy-efficient insights, useful to achieve performance-driven designs. Despite the main influence of the envelope parameters on the energy demand, it is beneficial to plan the functions in order to fulfil their energy and comfort requirements. Different functions play the leading roles in minimising different objectives, varying the depth, the orientation and the windows accordingly. In shallow buildings, energy-optimised configurations can save more than 37% of the total energy demand. However, the results are strictly dependent on the solution space defined by the parametric model. In practice, the designer needs to translate the underlying principles of space layout or to develop a site-specific optimisation.
Architecture, Urbanism & Building Sciences | Building Technology
Advisors/Committee Members: Turrin, M. (mentor), Tenpierik, M.J. (mentor), Du, T. (graduation committee), Delft University of Technology (degree granting institution).
Subjects/Keywords: Space Layout; Energy Efficiency; Optimisation; Performative computational architecture; Layout Optimization; energy performance
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APA (6th Edition):
Fumagalli, A. (. (2020). Energy Space Layout: Designing space layout with optimised energy performance. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:117335ea-4c43-4796-9ad7-d580403fcb35
Chicago Manual of Style (16th Edition):
Fumagalli, Andrea (author). “Energy Space Layout: Designing space layout with optimised energy performance.” 2020. Masters Thesis, Delft University of Technology. Accessed January 23, 2021.
http://resolver.tudelft.nl/uuid:117335ea-4c43-4796-9ad7-d580403fcb35.
MLA Handbook (7th Edition):
Fumagalli, Andrea (author). “Energy Space Layout: Designing space layout with optimised energy performance.” 2020. Web. 23 Jan 2021.
Vancouver:
Fumagalli A(. Energy Space Layout: Designing space layout with optimised energy performance. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Jan 23].
Available from: http://resolver.tudelft.nl/uuid:117335ea-4c43-4796-9ad7-d580403fcb35.
Council of Science Editors:
Fumagalli A(. Energy Space Layout: Designing space layout with optimised energy performance. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:117335ea-4c43-4796-9ad7-d580403fcb35
Colorado State University
9.
Schaad, Simon.
Dynamics and structure of stably stratified turbulence.
Degree: MS(M.S.), Civil and Environmental Engineering, 2012, Colorado State University
URL: http://hdl.handle.net/10217/75113
► The dynamics and turbulent structures of stably stratified turbulence are explored via direct numerical simulations (DNS). The structural features of stratified turbulence and its relationship…
(more)
▼ The dynamics and turbulent structures of stably stratified turbulence are explored via direct numerical simulations (DNS). The structural features of stratified turbulence and its relationship to the flow dynamics has been the
subject of many recent investigations. In strongly stratified turbulent flows, the formation of large-scale quasi-horizontal vortices in layers with strong vertical variability has been observed in laboratory experiments. Enstrophy isosurfaces of strongly stable flows indicate the emergence of randomly distributed 'pancake'-like structures with near horizontal orientation at later times. The strongly stratified simulations are diffusive and dominated by linear internal waves. The results suggest a decoupling between horizontal and vertical dynamics as the vertical dynamics can be described using rapid-distortion theory (RDT) while horizontal dynamics continue to be dominated by non-linear effects not captured by RDT. The integral flux Richardson number for decaying turbulence is the ratio of background potential energy gain to turbulent kinetic energy loss. The traditional flux-based formulation converges upon this ratio only when integrations are performed over an entire event, while the irreversible formulation converges rapidly without error from reversible effects. Mixing
efficiency is a property of the flow for energetic flow but becomes a property of the fluid for diffusive flows and
subject to Prandtl number effects. RDT models predict the flux Richardson number scales as the inverse Prandtl number at the diffusive limit when the Prandtl number is greater than unity. Mixing
efficiency comparisons between DNS and physical grid-tow experiments reveal a large discrepancy for strong stratification, which is attributed in part to the low Reynolds numbers attained in both DNS and grid-tow experiments. Overturns are unstable conditions where heavier fluid resides above lighter fluid. The collapse of these local instabilities produce additional patches of turbulence and mixing making overturns an important mechanism in stratified turbulence. The overturning structures in strongly stratified flow resemble the quasi-horizontal vorticity structures and were found to be correlated with increased horizontal vorticity. The Thorpe scale, a measure of overturning structure height, and the Ozmidov scale equate only at the critical condition where inertial and buoyancy effects are equal (i.e. the turbulent Froude number is unity). The error of inferred dissipation rates from equating the Thorpe and Ozmidov scales was found to be up to two orders of magnitude.
Advisors/Committee Members: Venayagamoorthy, Subhas Karan (advisor), Julien, Pierre Y. (committee member), Dasi, Lakshmi Prasad (committee member).
Subjects/Keywords: computational fluid dynamics; direct numerical simulations (DNS); fluid mechanics; mixing efficiency; oceanography; stratified turbulence
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APA (6th Edition):
Schaad, S. (2012). Dynamics and structure of stably stratified turbulence. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/75113
Chicago Manual of Style (16th Edition):
Schaad, Simon. “Dynamics and structure of stably stratified turbulence.” 2012. Masters Thesis, Colorado State University. Accessed January 23, 2021.
http://hdl.handle.net/10217/75113.
MLA Handbook (7th Edition):
Schaad, Simon. “Dynamics and structure of stably stratified turbulence.” 2012. Web. 23 Jan 2021.
Vancouver:
Schaad S. Dynamics and structure of stably stratified turbulence. [Internet] [Masters thesis]. Colorado State University; 2012. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/10217/75113.
Council of Science Editors:
Schaad S. Dynamics and structure of stably stratified turbulence. [Masters Thesis]. Colorado State University; 2012. Available from: http://hdl.handle.net/10217/75113
University of Adelaide
10.
Bi, Weiwei.
Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge.
Degree: 2016, University of Adelaide
URL: http://hdl.handle.net/2440/112041
► Water distribution systems (WDSs) are becoming increasingly complex and larger in scale due to the rapid growth of population and fast urbanization. Hence, they require…
(more)
▼ Water distribution systems (WDSs) are becoming increasingly complex and larger in scale due to the rapid growth of population and fast urbanization. Hence, they require high levels of investment for their construction and maintenance. This motivates the need to optimally design these systems, with the aim being to minimize the investment budget while maintaining high service quality. Over the past 25 years, a number of evolutionary algorithms (EAs) have been developed to achieve optimal design solutions for WDSs, representing a focal point of much research in this area. One issue that hinders EAs’ wide application in industry is their significant demand on
computational resources when handling real-world WDSs. In recognition of this, there has been a move from aiming to find the globally optimal solutions to identifying the best possible solutions within constrained
computational resources. While many studies have been undertaken to attain this goal, there have been limited efforts that use engineering knowledge to reduce the
computational effort. The research undertaken in this thesis is such an attempt, as it aims to efficiently identify near-optimal solutions with the aid of WDS design knowledge. This thesis presents a domain-knowledge based optimization framework that enables the near-optimal solutions (fronts) of WDS problems to be identified within constrained computing time. The knowledge considered includes (i) the relationship between pipe size and distance to the water source(s); (ii) the impact of flow velocities on optimal solutions; and (iii) the relationship between flow velocities and network resilience. This thesis consists of an Introduction, three chapters that are based around a series of three journal papers and a set of Conclusions and Recommendations for Further Work. The first paper introduces a new initialization method to assist genetic algorithms (GAs) to identify near-optimal solutions in a computationally efficient manner. This is attained by incorporating domain knowledge into the generation of the initial population of GAs. The results show that the proposed method performs better than the other three initialization methods considered, both in terms of
computational efficiency and the ability to find near-optimal solutions. The second paper investigates the relative impact of different algorithm initializations and searching mechanisms on the speed with which near-optimal solutions can be identified for large WDS design problems. Results indicate that EA parameterizations, that emphasize exploitation relative to exploration, enable near-optimal solutions to be identified earlier in the search, which is due to the “big bowl” shape of the fitness function for all of the WDS problems considered. Using initial solutions that are informed using domain knowledge can further increase the speed with which near-optimal solutions can be identified. The third publication extends the single-objective method in the first paper to a two-objective problem. The objectives considered are the minimization…
Advisors/Committee Members: Dandy, Graeme Clyde (advisor), Maier, Holger R. (advisor), School of Civil, Environmental and Mining Engineering (school).
Subjects/Keywords: optimization; evolutionary algorithm; water distribution systems; domain knowledge; heuristics; computational efficiency; Research by Publication
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CSE |
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Manager
APA (6th Edition):
Bi, W. (2016). Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/112041
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):
Bi, Weiwei. “Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge.” 2016. Thesis, University of Adelaide. Accessed January 23, 2021.
http://hdl.handle.net/2440/112041.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Bi, Weiwei. “Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge.” 2016. Web. 23 Jan 2021.
Vancouver:
Bi W. Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge. [Internet] [Thesis]. University of Adelaide; 2016. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/2440/112041.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Bi W. Improved evolutionary algorithm optimisation of water distribution systems using domain knowledge. [Thesis]. University of Adelaide; 2016. Available from: http://hdl.handle.net/2440/112041
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Northeastern University
11.
Lin, Yuzhang.
Reliable and efficient methods for identification of parameter and measurement errors in power networks.
Degree: PhD, Department of Electrical and Computer Engineering, 2018, Northeastern University
URL: http://hdl.handle.net/2047/D20294370
► The detection, identification, and correction of parameter and measurement errors (referred to as "error processing" below) are one of the core problems in the modeling…
(more)
▼ The detection, identification, and correction of parameter and measurement errors (referred to as "error processing" below) are one of the core problems in the modeling and monitoring of electric power networks. In this dissertation, analyses and methodologies are proposed in order to tackle different aspects of this problem.; To start with, the theoretical foundation of error processing is strengthened. The fundamental relations between the errors and their corresponding indicators (Lagrange multipliers and residuals) which are provided in the output of SE, are derived. Along with the development of this result, several remaining theoretical issues regarding error processing are addressed.; Closely following the aforementioned results, avenues to enhance the power of parameter error detection and estimation methods are presented. They are aimed at reliably processing the "weakly detectable errors" which are likely to be missed by existing approaches. The proposed solutions include exploitation of multiple measurement scans, and strategic use of phasor measurement units (PMUs).; A critical consideration in real-world implementation, namely the computational efficiency of error processing approaches is subsequently addressed in this dissertation. Solutions are presented to tackle the computational bottlenecks at different stages of error processing. They include efficient computation of the covariance matrix associated with Lagrange multipliers, linear correction of parameter errors, and simultaneous identification of multiple non-interacting measurement errors.; This dissertation also seeks another avenue to process the errors by directly using robust state estimation. A novel approach named Extended Least Absolute Value State Estimator (ELAV SE) is proposed for this purpose. It is the first state estimation approach for power systems that remains robust in the presence of both parameter and measurement errors, while automatically identifying and estimating these errors at the same time.; Finally, the dissertation considers some of the cyber-security issues related to power system modeling. Based on the earlier studies in this dissertation, it is shown that by strategically injecting errors into the model parameter database, certain network applications involving the operation of electricity markets can be manipulated, while detection of such attacks will be highly unlikely. The criticality of ensuring the accuracy and security of the parameter database is thus demonstrated.
Subjects/Keywords: anomaly detection; computational efficiency; cyber security; parameter estimation; power systems; state estimation
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Export
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APA (6th Edition):
Lin, Y. (2018). Reliable and efficient methods for identification of parameter and measurement errors in power networks. (Doctoral Dissertation). Northeastern University. Retrieved from http://hdl.handle.net/2047/D20294370
Chicago Manual of Style (16th Edition):
Lin, Yuzhang. “Reliable and efficient methods for identification of parameter and measurement errors in power networks.” 2018. Doctoral Dissertation, Northeastern University. Accessed January 23, 2021.
http://hdl.handle.net/2047/D20294370.
MLA Handbook (7th Edition):
Lin, Yuzhang. “Reliable and efficient methods for identification of parameter and measurement errors in power networks.” 2018. Web. 23 Jan 2021.
Vancouver:
Lin Y. Reliable and efficient methods for identification of parameter and measurement errors in power networks. [Internet] [Doctoral dissertation]. Northeastern University; 2018. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/2047/D20294370.
Council of Science Editors:
Lin Y. Reliable and efficient methods for identification of parameter and measurement errors in power networks. [Doctoral Dissertation]. Northeastern University; 2018. Available from: http://hdl.handle.net/2047/D20294370
Univerzitet u Beogradu
12.
Kostić, Svetlana M., 1978-.
Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija.
Degree: Građevinski fakultet, 2014, Univerzitet u Beogradu
URL: https://fedorabg.bg.ac.rs/fedora/get/o:8794/bdef:Content/get
► Građevinarstvo-Teorija konstrukcija / Civil engineering- Theory of structures
Predmet disertacije je efikasna nelinearna analiza okvirnih konstrukcija grednim konačnim elementima sa težištem na modeliranju materijalnih nelinearnosti.…
(more)
▼ Građevinarstvo-Teorija konstrukcija / Civil
engineering- Theory of structures
Predmet disertacije je efikasna nelinearna analiza
okvirnih konstrukcija grednim konačnim elementima sa težištem na
modeliranju materijalnih nelinearnosti. Geometrijska nelinearnost
se uzima u obzir poznatim metodama. U tezi su analizirana i
unapređena dva gredna konačna elementa: fiber element i element
koncentrisane plastičnosti i napisan je sopstveni kompjuterski
program kojim su elementi implementirani u postojeći open-source
program za analizu konstrukcija – FEDEASLab. Tokom rada na tezi,
ostvareni su sledeći ciljevi. Izvršena je optimizacija integracije
poprečnog preseka čeličnih i armirano-betonskih elemenata u cilju
poboljšanja efikasnosti fiber elemenata kako pri cikličnom
pseudo-statičkom opterećenju, tako i pri nelinearnoj dinamičkoj
analizi pojedinih delova i čitave konstrukcije. Formulisana su
praktična pravila i definisane jasne smernice za diskretizaciju
poprečnog preseka čeličnog I profila i pravougaonog
armiranobetonskog preseka, u zavisnosti od vrste analize koja se
sprovodi i željene tačnosti. Razvijen je novi konačni elementa iz
grupe elemenata koncentrisane plastičnosti koji prevazilazi
ograničenja postojećeg elasto-plastičnog elementa kao što su
nemogućnost opisivanja postepene plastifikacije poprečnog preseka i
opisivanja ponašanja materijala sa ojačanjem. Pri tome, element je
zadržao svoju veliku kompjutersku efikasnost koja je osnovna
prednost elemenata koncentrisane plastičnosti. Za određivanje
stanja elementa razvijena su dva algoritma prema “general closest
point projection” i “convex cutting plane” return mapping
algoritmima i analizirana je zavisnost konvergencije od
implementiranog algoritma. Mogućnosti novog elementa za modeliranje
okvirnih konstrukcija pri delovanju statičkog i dinamičkog
opterećenja su potvrđene kroz niz numeričkih primera. Specijalna
pažnja je posvećena primeni novog GP elementa za modeliranje CFT
stubova spregnutih konstrukcija...
Advisors/Committee Members: Šumarac, Dragoslav, 1955-.
Subjects/Keywords: beam/column element; cross-section; nonlinear analysis;
generalized plasticity; resultant plasticity; computational
efficiency
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APA (6th Edition):
Kostić, Svetlana M., 1. (2014). Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija. (Thesis). Univerzitet u Beogradu. Retrieved from https://fedorabg.bg.ac.rs/fedora/get/o:8794/bdef:Content/get
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):
Kostić, Svetlana M., 1978-. “Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija.” 2014. Thesis, Univerzitet u Beogradu. Accessed January 23, 2021.
https://fedorabg.bg.ac.rs/fedora/get/o:8794/bdef:Content/get.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Kostić, Svetlana M., 1978-. “Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija.” 2014. Web. 23 Jan 2021.
Vancouver:
Kostić, Svetlana M. 1. Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija. [Internet] [Thesis]. Univerzitet u Beogradu; 2014. [cited 2021 Jan 23].
Available from: https://fedorabg.bg.ac.rs/fedora/get/o:8794/bdef:Content/get.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Kostić, Svetlana M. 1. Model generalisane plastičnosti kod nelinearne analize
prostornih okvirnih konstrukcija. [Thesis]. Univerzitet u Beogradu; 2014. Available from: https://fedorabg.bg.ac.rs/fedora/get/o:8794/bdef:Content/get
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
KTH
13.
Lans, Patrik.
Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone.
Degree: Mechanics, 2016, KTH
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194498
► This thesis includes a numerical comparison of different turbulence models and particle models in terms of convergence time and physical accuracy. A cyclone is…
(more)
▼ This thesis includes a numerical comparison of different turbulence models and particle models in terms of convergence time and physical accuracy. A cyclone is used as the computational domain. Cyclones are common devices for separating two or more substances. The work is divided into an experimental part and a numerical part. In the experiments, characteristics of the cyclone were measured. This data is then used to evaluate different numerical modeling approaches. The numerical part consists of two parts, namely single phase flow and multiphase flow, where different modeling aspects are examined and presented. Furthermore, important parameters that characterize a cyclone, such as pressure drop and separation efficiency, are calculated. The separation efficiency, i.e. how much dust that actually goes to the dust bin, is calculated for two different types of dust. The software used for the numerical simulations has been Star-CCM+.
Subjects/Keywords: computational fluid dynamics (CFD); cyclone; separation efficiency; Engineering and Technology; Teknik och teknologier
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APA ·
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APA (6th Edition):
Lans, P. (2016). Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone. (Thesis). KTH. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194498
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):
Lans, Patrik. “Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone.” 2016. Thesis, KTH. Accessed January 23, 2021.
http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194498.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Lans, Patrik. “Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone.” 2016. Web. 23 Jan 2021.
Vancouver:
Lans P. Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone. [Internet] [Thesis]. KTH; 2016. [cited 2021 Jan 23].
Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194498.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Lans P. Numerical Methods for Simulating Separation in a Vacuum Cleaner Cyclone. [Thesis]. KTH; 2016. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194498
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
14.
YU ZHOUZHONG.
APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES.
Degree: 1989, National University of Singapore
URL: https://scholarbank.nus.edu.sg/handle/10635/153210
Subjects/Keywords: computational efficiency; and realistic flight commands.
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APA (6th Edition):
ZHOUZHONG, Y. (1989). APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES. (Thesis). National University of Singapore. Retrieved from https://scholarbank.nus.edu.sg/handle/10635/153210
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):
ZHOUZHONG, YU. “APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES.” 1989. Thesis, National University of Singapore. Accessed January 23, 2021.
https://scholarbank.nus.edu.sg/handle/10635/153210.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
ZHOUZHONG, YU. “APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES.” 1989. Web. 23 Jan 2021.
Vancouver:
ZHOUZHONG Y. APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES. [Internet] [Thesis]. National University of Singapore; 1989. [cited 2021 Jan 23].
Available from: https://scholarbank.nus.edu.sg/handle/10635/153210.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
ZHOUZHONG Y. APPLICATION OF MICROCOMPUTERS IN ENERGY MONITORING AND ANALYSIS FOR MANUFACTURING INDUSTRIES. [Thesis]. National University of Singapore; 1989. Available from: https://scholarbank.nus.edu.sg/handle/10635/153210
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Michigan State University
15.
Hoyle, Zachary.
Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines.
Degree: 2017, Michigan State University
URL: http://etd.lib.msu.edu/islandora/object/etd:6940
► "This thesis work investigates the applicability of literature recommendations regarding specific speed and Zweifel coefficient for low head axial hydraulic turbines with constant blade thickness…
(more)
▼ "This thesis work investigates the applicability of literature recommendations regarding specific speed and Zweifel coefficient for low head axial hydraulic turbines with constant blade thickness circular arc blade profiles, and no inlet guide vane. Highest efficiency was observed in Computational Fluid Dynamics (CFD) investigations for the designs running at speeds 12-33% that of the speed recommended by the Cordier line. Designs that followed the Zweifel coefficient recommendations of the literature in range of 0.8-1.1 demonstrated highest efficiency in CFD investigations. To test the applicability of the Cordier line recommendations for machines of this type, designs at differing specifications were tested at six different rotational speeds. Peak efficiency was measured at specific speeds between 1.4 and 1.9, compared to the Cordier-recommended value of 5.5 to 6.1. Next designs with differing values of Zweifel coefficient were simulated at the rotational speed at which highest efficiency was measured for each set of specifications. Zweifel coefficient was altered by changing the axial blade length. It was found that highest efficiency was measured at Zweifel coefficients between 0.8 and 1.1. The designs with higher axial blade lengths had lower Zweifel coefficient, and experienced greater friction losses. Decreasing blade length and increased Zweifel coefficients were correlated with more severe velocity gradients at the leading edge, increased flow deviation and areas of low pressure where cavitation could occur. Designs with the shortest blades (Zwefiel coefficient above 1.2) experienced greater velocity gradients and turbulence at the trailing edge and decreased efficiency." – Page ii.
Online resource;
Advisors/Committee Members: Mueller, Norbert, Xiao, Xinran, Engeda, Abraham.
Subjects/Keywords: Hydraulic turbines – Design and construction; Mechanical efficiency; Computational fluid dynamics; Mechanical engineering
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APA ·
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Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Hoyle, Z. (2017). Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines. (Thesis). Michigan State University. Retrieved from http://etd.lib.msu.edu/islandora/object/etd:6940
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):
Hoyle, Zachary. “Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines.” 2017. Thesis, Michigan State University. Accessed January 23, 2021.
http://etd.lib.msu.edu/islandora/object/etd:6940.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Hoyle, Zachary. “Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines.” 2017. Web. 23 Jan 2021.
Vancouver:
Hoyle Z. Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines. [Internet] [Thesis]. Michigan State University; 2017. [cited 2021 Jan 23].
Available from: http://etd.lib.msu.edu/islandora/object/etd:6940.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Hoyle Z. Applicability of specific speed and Zweifel coefficient recommendations to low head axial hydraulic turbines. [Thesis]. Michigan State University; 2017. Available from: http://etd.lib.msu.edu/islandora/object/etd:6940
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
University of Tasmania
16.
Ansarifard, N.
CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters.
Degree: 2019, University of Tasmania
URL: https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf
;
Ansarifard,
N
ORCID:
0000-0002-7619-1697
<https://orcid.org/0000-0002-7619-1697>
2019
,
'CFD
analysis
and
optimisation
of
unidirectional
radial
turbine
geometry
for
application
with
oscillating
water
column
wave
energy
converters',
PhD
thesis,
University
of
Tasmania.
► An oscillating-water-column (OWC) is a popular device for harnessing the power of ocean waves. A key component in the system is the air turbine, which…
(more)
▼ An oscillating-water-column (OWC) is a popular device for harnessing the power of ocean waves. A key component in the system is the air turbine, which operates as the power take-off unit (PTO) converting pneumatic power to mechanical. The turbine is probably the most complicated geometry in the system and is mainly designed in either an axial or radial configuration.
The efficiency of a conventional radial impulse turbine (bidirectional version) rarely reaches more than 40%, which makes it a less efficient choice than axial turbines. However, the radial configuration has some advantageous features compared with the axial turbine, such as lower bearing loads and easier manufacturing. Current research on unidirectional radial impulse turbines shows a higher resistance to backflow and negative torque than the axial turbines, which is particularly useful in a twin-turbine configuration of the OWC system. The work described in this thesis is concerned with efficiency improvement of unidirectional radial air turbines using computational engineering approaches.
In this research, optimisation techniques were used in conjunction with Computational-Fluid-Dynamics (CFD) simulations to maximize efficiency of a unidirectional radial turbine for a vented OWC (where air flows through the turbine in only one direction). A parametric turbine geometry was created by varying geometrical features to control the shape of upstream guide vanes, rotor blades, downstream guide vanes and the duct section. This method led to flexibility in design and adjustment of rotating and stationary elements. The optimised design obtained significantly improved torque production for a single flow direction due to its highly-asymmetric rotor blades and well-adjusted inlet guide vanes. A parameter sensitivity analysis was performed using the response surface method and the optimum geometry of the turbine was obtained from a large design space (containing over 140 design cases for the inflow turbine and around 80 design cases for the outflow turbine).
This research provides a detailed analysis on the impact of each parameter on the turbine performance and is conducted in four steps. First, identifying the design drawbacks and sources of energy loss in the initial geometry of a unidirectional radial turbine and suggesting design modifications. Second, studying the turbine performance in a vented OWC and finding the optimum design of the turbine in the centripetal configuration (inflow mode). Third, studying the turbine performance in the vented OWC and optimising the turbine design for maximized efficiency in centrifugal configuration (outflow mode). Finally, comparing the global efficiency of the optimised inflow and outflow radial turbines considering their application with the vented OWC and twin-turbine OWC configurations.
This study contributed to a significant increase in energy capture of unidirectional radial impulse turbines compared to their bidirectional version, where the optimised centripetal and centrifugal turbine configurations of this…
Subjects/Keywords: Unidirectional radial air turbine; Design optimization; Efficiency maximization; Vented oscillating water column; Computational fluid dynamics
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Manager
APA (6th Edition):
Ansarifard, N. (2019). CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters. (Thesis). University of Tasmania. Retrieved from https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf ; Ansarifard, N ORCID: 0000-0002-7619-1697 <https://orcid.org/0000-0002-7619-1697> 2019 , 'CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters', PhD thesis, University of Tasmania.
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):
Ansarifard, N. “CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters.” 2019. Thesis, University of Tasmania. Accessed January 23, 2021.
https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf ; Ansarifard, N ORCID: 0000-0002-7619-1697 <https://orcid.org/0000-0002-7619-1697> 2019 , 'CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters', PhD thesis, University of Tasmania..
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Ansarifard, N. “CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters.” 2019. Web. 23 Jan 2021.
Vancouver:
Ansarifard N. CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters. [Internet] [Thesis]. University of Tasmania; 2019. [cited 2021 Jan 23].
Available from: https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf ; Ansarifard, N ORCID: 0000-0002-7619-1697 <https://orcid.org/0000-0002-7619-1697> 2019 , 'CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters', PhD thesis, University of Tasmania..
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Ansarifard N. CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters. [Thesis]. University of Tasmania; 2019. Available from: https://eprints.utas.edu.au/32532/1/Ansarifard_whole_thesis.pdf ; Ansarifard, N ORCID: 0000-0002-7619-1697 <https://orcid.org/0000-0002-7619-1697> 2019 , 'CFD analysis and optimisation of unidirectional radial turbine geometry for application with oscillating water column wave energy converters', PhD thesis, University of Tasmania.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Delft University of Technology
17.
Neeskens, Tim (author).
Thin glass composites: based on a structural efficiency increasing design strategy.
Degree: 2018, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:676851fc-0556-4e1e-ac6a-dcdf4b7cfc0a
► The research focuses on the combined use of thin glass and a 3D printed spacer pattern. The goal is to design a possible solution to…
(more)
▼ The research focuses on the combined use of thin glass and a 3D printed spacer pattern. The goal is to design a possible solution to use thin glass in architecture. In the first part of the thesis background research on thin glass, additive manufacturing, adhesive bonding and structural geometry is conducted. This has lead to results to formulate the criteria for the design. Important is that the pattern used in is printed continuously without support material and has enough surface area to deal with the shear stress when bended. To start the design process, three topologies are presented on which later designs are based. Those topologies are a straight extruded surface pattern, a lattice member structure and continuous pattern with cut-offs. Based on those topologies five designs are made from which the straight extruded Voronoi pattern is the one to continue with in the design because it scores the best on the criteria mentioned above. The Voronoi pattern is used in a several strategies which developed into the strategy which used gradient mapping based on a structural analysis to create a Voronoi pattern to represent the structural shape. Thereby also the Voronoi pattern based on LLoyd’s algorithm is tested since it presents the possibility to create a more evenly spread Voronoi pattern. To validate the results from the design strategy, FEA is used for five four side supported panels, five two side supported panels, two panels based on Lloyd’s algorithm and three lab test specimen. Those panels are analysed on deflection, principal stresses and shear stress. To make them comparable they translated to a value so they all represent the same amount of used material. The results of the analysis show a increase in resistance against deflection of 4,8% in the two side supported panels and 2,7% in the four side supported panels. For three of the panels is a lab specimen prepared. Those panel have a size of 300 x 150 mm and will be used in three point bending test in the lab. To conclude the research a final mock up with size of 1210 x 660 mm is built and will be placed in the window of the existing Product Development test lab at the TU Delft. Also is the panel used in a case study for the PD test lab. A facade redesign is made to demonstrate how the panel based on Lloyd’s algorithm can be used as a facade element.
Architecture, Urbanism and Building Sciences | Building Technology
Advisors/Committee Members: Louter, Christian (mentor), Turrin, Michela (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: Thin Glass; Additive Manufacturing; Polymers; FEA; Efficiency; computational design; Structural Design; Gradient mapping; Facade
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APA (6th Edition):
Neeskens, T. (. (2018). Thin glass composites: based on a structural efficiency increasing design strategy. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:676851fc-0556-4e1e-ac6a-dcdf4b7cfc0a
Chicago Manual of Style (16th Edition):
Neeskens, Tim (author). “Thin glass composites: based on a structural efficiency increasing design strategy.” 2018. Masters Thesis, Delft University of Technology. Accessed January 23, 2021.
http://resolver.tudelft.nl/uuid:676851fc-0556-4e1e-ac6a-dcdf4b7cfc0a.
MLA Handbook (7th Edition):
Neeskens, Tim (author). “Thin glass composites: based on a structural efficiency increasing design strategy.” 2018. Web. 23 Jan 2021.
Vancouver:
Neeskens T(. Thin glass composites: based on a structural efficiency increasing design strategy. [Internet] [Masters thesis]. Delft University of Technology; 2018. [cited 2021 Jan 23].
Available from: http://resolver.tudelft.nl/uuid:676851fc-0556-4e1e-ac6a-dcdf4b7cfc0a.
Council of Science Editors:
Neeskens T(. Thin glass composites: based on a structural efficiency increasing design strategy. [Masters Thesis]. Delft University of Technology; 2018. Available from: http://resolver.tudelft.nl/uuid:676851fc-0556-4e1e-ac6a-dcdf4b7cfc0a
University of Melbourne
18.
Bunster Milnes, Victor Andres.
A mass personalisation model to enhance added residential value in social housing.
Degree: 2016, University of Melbourne
URL: http://hdl.handle.net/11343/118547
► It is a major challenge in developing countries to ensure access to quality social housing. Standardised mass housing is still ubiquitously used when addressing pressing…
(more)
▼ It is a major challenge in developing countries to ensure access to quality social housing. Standardised mass housing is still ubiquitously used when addressing pressing shortages, regardless of well-documented problems with this form of provision. Although strategies based upon participation and self-help action may offer significant benefits, these delivery approaches are difficult to scale up and thus offer a feasible alternative to mass housing. There might be many reasons for this, but one is readily evident: mass production simplifies design and development, thus a more efficient housing delivery system. This thesis acknowledges the challenge and explores mass personalisation as an alternative approach to reconciling quality and quantity within the constraints of current social housing regulation and mainstream production systems.
Mass personalisation is a particular approach to mass customisation in which the attributes of a product or service are tailored towards the implicit requirements of individual users. If mass customisation seeks to offer enhanced variability with costs close those of mass production, mass personalisation seeks to meet the requirements of individual users more closely than is possible through traditional product specification approaches. This thesis demonstrates that mass personalisation can inform the delivery of cost-effective dwellings capable of facilitating the changing residential requirements of individual households and thus enhance their residential value throughout their life cycles.
The Chilean social housing program is used here as a case study context to explore current qualitative problems and to propose a mass personalisation model focused on the co-creation of residential value. A significant factor in household satisfaction is identified as the ability of occupants to personalise their home, influencing both user expectations and their perceived quality of the residential environment. Data gathered revealed that thermal performance was a key factor, reflecting expectations of the relationship between occupants and providers (i.e., personalisation as a service) as well as the impact that self-construction (i.e., personalisation of the product) can have on energy consumption for space heating. These insights are formalised and used as a conceptual foundation to structure a mass personalisation model that represents housing delivery as an ecosystem of users, products, and services in which the continuous provision of personalised user experiences is enabled. In support of the co-creation process, the proposed model draws upon on web personalisation and data mining techniques to profile household requirements using public datasets and direct user input, to automate the generation of housing alternatives using modular housing components, and to identify discrete solution sets of enhanced residential value. This model has been implemented as a proof-of-concept configurator with a particular focus on the provision of energy efficient dwellings and then evaluated under…
Subjects/Keywords: personalisation; mass customisation; computational modelling; data mining; residential satisfaction; value added; energy efficiency; social housing
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APA (6th Edition):
Bunster Milnes, V. A. (2016). A mass personalisation model to enhance added residential value in social housing. (Doctoral Dissertation). University of Melbourne. Retrieved from http://hdl.handle.net/11343/118547
Chicago Manual of Style (16th Edition):
Bunster Milnes, Victor Andres. “A mass personalisation model to enhance added residential value in social housing.” 2016. Doctoral Dissertation, University of Melbourne. Accessed January 23, 2021.
http://hdl.handle.net/11343/118547.
MLA Handbook (7th Edition):
Bunster Milnes, Victor Andres. “A mass personalisation model to enhance added residential value in social housing.” 2016. Web. 23 Jan 2021.
Vancouver:
Bunster Milnes VA. A mass personalisation model to enhance added residential value in social housing. [Internet] [Doctoral dissertation]. University of Melbourne; 2016. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/11343/118547.
Council of Science Editors:
Bunster Milnes VA. A mass personalisation model to enhance added residential value in social housing. [Doctoral Dissertation]. University of Melbourne; 2016. Available from: http://hdl.handle.net/11343/118547
Virginia Tech
19.
Salama, Iman Mohamed.
Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques.
Degree: PhD, Electrical and Computer Engineering, 1997, Virginia Tech
URL: http://hdl.handle.net/10919/30753
► The TLM was initially formulated and developed in the time domain. One key issue in a time domain analysis approach is the computational efficiency, where…
(more)
▼ The TLM was initially formulated and developed in the time domain. One key issue in a time domain analysis approach is the
computational efficiency, where a single impulsive excitation could yield information over a wide frequency range. Also, it may be more natural and realistic to model non linear and frequency dispersive properties in the time domain rather than in the frequency domain. However, in some circumstances, frequency domain analysis may be more appealing. This might be due to the fact that the traditional teaching of electromagnetics emphasizes frequency domain concepts as frequency dispersive constitutive parameters, complex frequency dependent impedances and reflection coefficients. It might be even easier and more direct to be able to model these parameters in frequency domain rather than trying to synthesize an equivalent time domain model. The only limitation of frequency domain analysis, is that the analysis has to be repeated at every frequency point in the frequency range of interest.
In this work, a new frequency domain TLM (FDTLM) approach is introduced which combines the superior features of both the time domain and the frequency domain TLM. The approach is based on a steady state analysis in the frequency domain using transient analysis techniques and hence is referred to as TFDTLM. In this approach, the link lines impedances are derived in the frequency domain and are chosen to model the frequency dispersive material parameters. The impedances and propagation constants are allowed to be complex and frequency dependent. Consequently, the TFDTLM can provide more accurate modeling for wave propagation in a frequency dispersive medium. The approach was inspired by the concept of bounce diagram in the time domain and the equivalent frequency domain bounce diagram.
To make the TFDTLM approach computationally efficient as compared to other frequency domain TLM approaches, it was critical to maintain some relationship between the mesh response at one frequency point and any other frequency point. The goal was to be able to extract all the frequency domain information in a wide frequency range by performing only one simulation. To achieve this, the transitions between two adjacent cell in all media expressed by (exp(-gamma*L)) have to be expressed in terms of the propagation factor of some reference medium chosen to be the medium with the least propagation delay. This was done with the aid of a digital filter approximation that can be implemented iteratively inside the TLM mesh. The filter can be thought of as some type of compensation equivalent to the stubs in a time domain TLM, yet more accurate and more general. An important advantage of the TFDTLM is that it can easily be interfaced with existing time domain TLM schemes as well as absorbing boundary conditions originally developed for time domain TLM with the slightest modifications. The TFDTLM is implemented a three dimensional mesh and the superior performance of the new approach in modeling lossy inhomogeneous media is demonstrated.
The…
Advisors/Committee Members: Riad, Sedki Mohamed (committeechair), Su, Wansheng (committee member), Scales, Wayne A. (committee member), Christopoulos, C. (committee member), Elshabini-Riad, Aicha A. (committee member), Besieris, Ioannis M. (committee member).
Subjects/Keywords: Electromagnetics; Computational efficiency; Frequency domain TLM
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APA (6th Edition):
Salama, I. M. (1997). Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/30753
Chicago Manual of Style (16th Edition):
Salama, Iman Mohamed. “Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques.” 1997. Doctoral Dissertation, Virginia Tech. Accessed January 23, 2021.
http://hdl.handle.net/10919/30753.
MLA Handbook (7th Edition):
Salama, Iman Mohamed. “Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques.” 1997. Web. 23 Jan 2021.
Vancouver:
Salama IM. Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques. [Internet] [Doctoral dissertation]. Virginia Tech; 1997. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/10919/30753.
Council of Science Editors:
Salama IM. Tfdtlm: a New Computationally Efficient Frequency Domain Tlm Based on Transient Analysis Techniques. [Doctoral Dissertation]. Virginia Tech; 1997. Available from: http://hdl.handle.net/10919/30753
University of California – Berkeley
20.
LeDell, Erin.
Scalable Ensemble Learning and Computationally Efficient Variance Estimation.
Degree: Biostatistics, 2015, University of California – Berkeley
URL: http://www.escholarship.org/uc/item/3kb142r2
► Ensemble machine learning methods are often used when the true prediction function is not easily approximated by a single algorithm. The Super Learner algorithm is…
(more)
▼ Ensemble machine learning methods are often used when the true prediction function is not easily approximated by a single algorithm. The Super Learner algorithm is an ensemble method that has been theoretically proven to represent an asymptotically optimal system for learning. The Super Learner, also known as stacking, combines multiple, typically diverse, base learning algorithms into a single, powerful prediction function through a secondary learning process called metalearning. Although ensemble methods offer superior performance over their singleton counterparts, there is an implicit computational cost to ensembles, as it requires training multiple base learning algorithms. We present several practical solutions to reducing the computational burden of ensemble learning while retaining superior model performance, along with software, code examples and benchmarks. Further, we present a generalized metalearning method for approximating the combination of the base learners which maximizes a model performance metric of interest. As an example, we create an AUC-maximizing Super Learner and show that this technique works especially well in the case of imbalanced binary outcomes. We conclude by presenting a computationally efficient approach to approximating variance for cross-validated AUC estimates using influence functions. This technique can be used generally to obtain confidence intervals for any estimator, however, due to the extensive use of AUC in the field of biostatistics, cross-validated AUC is used as a practical, motivating example.The goal of this body of work is to provide new scalable approaches to obtaining the highest performing predictive models while optimizing any model performance metric of interest, and further, to provide computationally efficient inference for that estimate.
Subjects/Keywords: Biostatistics; Computer engineering; Statistics; Computational Efficiency; Cross-validation; Ensemble Learning; Influence Functions; Machine Learning; Parallel Computing
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APA (6th Edition):
LeDell, E. (2015). Scalable Ensemble Learning and Computationally Efficient Variance Estimation. (Thesis). University of California – Berkeley. Retrieved from http://www.escholarship.org/uc/item/3kb142r2
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):
LeDell, Erin. “Scalable Ensemble Learning and Computationally Efficient Variance Estimation.” 2015. Thesis, University of California – Berkeley. Accessed January 23, 2021.
http://www.escholarship.org/uc/item/3kb142r2.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
LeDell, Erin. “Scalable Ensemble Learning and Computationally Efficient Variance Estimation.” 2015. Web. 23 Jan 2021.
Vancouver:
LeDell E. Scalable Ensemble Learning and Computationally Efficient Variance Estimation. [Internet] [Thesis]. University of California – Berkeley; 2015. [cited 2021 Jan 23].
Available from: http://www.escholarship.org/uc/item/3kb142r2.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
LeDell E. Scalable Ensemble Learning and Computationally Efficient Variance Estimation. [Thesis]. University of California – Berkeley; 2015. Available from: http://www.escholarship.org/uc/item/3kb142r2
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
UCLA
21.
Roth-Johnson, Perry.
Aero-Structural Design Investigations for Biplane Wind Turbine Blades.
Degree: Aerospace Engineering, 2014, UCLA
URL: http://www.escholarship.org/uc/item/7j890287
► Large wind turbine blades are being developed at lengths of 85-125 meters, in order to improve energy capture and reduce the cost of wind energy.…
(more)
▼ Large wind turbine blades are being developed at lengths of 85-125 meters, in order to improve energy capture and reduce the cost of wind energy. Bending loads in the inboard region of the blade make large blade development challenging. The "biplane blade" design was proposed to use a biplane inboard region to improve the design of the inboard region and improve overall performance of large blades. This work uses a "structures-first" approach with aero-structural analyses to (1) examine the feasibility of the biplane blade, (2) determine how the dimensions of the biplane inboard region affect performance, and (3) compare the aero-structural performance of a 100-meter biplane blade to the Sandia SNL100-00 reference blade. Two-dimensional CFD simulations were used to compare the aerodynamic performance of a biplane with a thick monoplane. The lift-to-drag ratio and the maximum lift coefficient is significantly greater for the biplane than the thick monoplane for angles of attack of 0-15 degrees. Analytical methods and beam finite elements with cross-sectional analysis were both used to examine the performance of biplane blade structures. These structures varied in complexity from isotropic spars to composite spars to composite full blades. In each case, biplane blade structures were compared to monoplane blade structures of the same length, mass, and complexity. Simple load cases were applied to each structure and their displacements, bending moments, axial forces, and stresses were compared. Similar performance trends are identified with both the analytical and computational models. Parametric analyses show that gap-to-chord ratios bewteen 1.0-1.2 and joint length-to-span ratios of about 0.5 give good aero-structural performance. At the tip, the biplane blade increases flapwise structural efficiency by 20-40%, depending on the load. Edgewise structural efficiency was decreased by 27-35% at the tip. The benefits for the inboard region could lead to mass reductions in wind turbine blades. Innovations that create lighter blades can make large blades a reality, suggesting that the biplane blade is an attractive design for large (100-meter) blades.
Subjects/Keywords: Aerospace engineering; beam finite element analysis; biplane inboard region; computational fluid dynamics; cross-sectional analysis; structural efficiency; wind turbine blade design
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APA (6th Edition):
Roth-Johnson, P. (2014). Aero-Structural Design Investigations for Biplane Wind Turbine Blades. (Thesis). UCLA. Retrieved from http://www.escholarship.org/uc/item/7j890287
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):
Roth-Johnson, Perry. “Aero-Structural Design Investigations for Biplane Wind Turbine Blades.” 2014. Thesis, UCLA. Accessed January 23, 2021.
http://www.escholarship.org/uc/item/7j890287.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Roth-Johnson, Perry. “Aero-Structural Design Investigations for Biplane Wind Turbine Blades.” 2014. Web. 23 Jan 2021.
Vancouver:
Roth-Johnson P. Aero-Structural Design Investigations for Biplane Wind Turbine Blades. [Internet] [Thesis]. UCLA; 2014. [cited 2021 Jan 23].
Available from: http://www.escholarship.org/uc/item/7j890287.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Roth-Johnson P. Aero-Structural Design Investigations for Biplane Wind Turbine Blades. [Thesis]. UCLA; 2014. Available from: http://www.escholarship.org/uc/item/7j890287
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Cornell University
22.
Tan, Sue Nee.
COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION.
Degree: PhD, Civil and Environmental Engineering, 2017, Cornell University
URL: http://hdl.handle.net/1813/56992
► Hydropower generation, though a centuries-old technology, is gaining new relevance as a way to integrate renewable energy sources to the power grid. This dissertation describes…
(more)
▼ Hydropower generation, though a centuries-old technology, is gaining new relevance as a way to integrate renewable energy sources to the power grid. This dissertation describes the development of efficient models for optimizing hydropower operations to address the competing priorities of renewable generation integration, economically efficient hydropower generation, and environmental stewardship, while still being able to maximize the value of wind and hydropower generation. The models are demonstrated using the 10-reservoir Federal Columbia River Power System in the Pacific Northwest in the U.S.A.
Our computationally efficient nonlinear optimization model for the 10-reservoir system employs variable time step lengths and precomputed powerhouse functions and operating rules. Having shorter 8-hour time steps in the first few days of the model then transitioning to a coarser 24-hour time step for flow routing in the later stages results in optimization runtimes being decreased to 1/3rd to 1/6th of the time it takes to run the optimization with all 8-hour time steps. Our powerhouse functions reduced the many dispatch and loading decisions for multiple turbines at a hydropower project into a powerhouse generation as a function of total flow. The nonlinear optimization model incorporates forecasted inflow, hydropower plant operation, contracted energy loads, and the hydropower utility’s interaction with wholesale energy markets. When applicable the model also includes special seasonal constraints for fish addressing specified turbine operations and upper and lower bounds on spils. The opportunity costs of meeting these environmental constraints can be estimated. Additionally, we consider the market power of a very large hydropower producer in a regional market. For an entity with market power, maximizing avoided cost will result in prices that are very similar across periods, which is the economically efficient solution. In contrast, maximizing revenue will result in prices that are not balanced across periods, which may result in monopolistic behavior.
To address renewable integration, our stochastic dynamic programming and nonlinear programming model builds upon the aforementioned framework with a time decomposition approach to optimize the hourly operations of a subset of the 10-reservoir hydropower system under wind generation uncertainty. This model also includes the effect that wind generation has on market prices, in addition to the hydro utility market power. We showed how introducing increasing levels of wind generation uncertainty causes the model to hedge by decreasing its commitment to the wholesale electricity market. The model estimates the opportunity costs of providing hour-by-hour balancing of the wind generation to a wind power generation owner.
Advisors/Committee Members: Shoemaker, Christine Ann (chair), Topaloglu, Huseyin (committee member), Liu, Philip Li-Fan (committee member), Stedinger, Jery Russell (committee member).
Subjects/Keywords: Renewable Integration; Operations research; Optimization; Computational efficiency; Hydropower systems operation; short-term planning; Unit dispatch and loading; Systems science
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APA ·
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APA (6th Edition):
Tan, S. N. (2017). COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION. (Doctoral Dissertation). Cornell University. Retrieved from http://hdl.handle.net/1813/56992
Chicago Manual of Style (16th Edition):
Tan, Sue Nee. “COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION.” 2017. Doctoral Dissertation, Cornell University. Accessed January 23, 2021.
http://hdl.handle.net/1813/56992.
MLA Handbook (7th Edition):
Tan, Sue Nee. “COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION.” 2017. Web. 23 Jan 2021.
Vancouver:
Tan SN. COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION. [Internet] [Doctoral dissertation]. Cornell University; 2017. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/1813/56992.
Council of Science Editors:
Tan SN. COMPUTATIONALLY EFFICIENT HYDROPOWER OPERATIONS OPTIMIZATION FOR LARGE CASCADED HYDROPOWER SYSTEMS REFLECTING MARKET POWER, FISH CONSTRAINTS, MULTI-TURBINE POWERHOUSES, AND RENEWABLE RESOURCE INTEGRATION. [Doctoral Dissertation]. Cornell University; 2017. Available from: http://hdl.handle.net/1813/56992
University of Michigan
23.
Pal, Pinaki.
Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.
Degree: PhD, Mechanical Engineering, 2016, University of Michigan
URL: http://hdl.handle.net/2027.42/120735
► To achieve cleaner and more efficient energy utilization, novel strategies in modern combustion devices operate using lean, premixed reactant mixtures at high pressures. Under these…
(more)
▼ To achieve cleaner and more efficient energy utilization, novel strategies in modern combustion devices operate using lean, premixed reactant mixtures at high pressures. Under these conditions, auto-ignition often becomes a dominant process for burning. Therefore, accurate prediction of auto-ignition characteristics is of paramount importance in successful implementation of these advanced combustion systems.
The first part of this dissertation focuses on auto-ignition characteristics at high-pressure, low-temperature conditions, relevant to modern gas turbine engines. In particular, strong (homogeneous) and weak (deflagration-dominant) ignition regimes in the presence of thermal inhomogeneities are computationally investigated. Predictive criteria based on Zel’dovich’s theory and passive scalar mixing, which can capture the ignition behavior a priori, are proposed and validated using extensive parametric tests of one-dimensional laminar systems of a lean syngas/air mixture. Subsequently, a non-dimensional scaling analysis is performed to derive regime criteria for turbulent reacting flows, leading to a turbulent ignition regime diagram. The regime diagram is then numerically validated against two-dimensional direct numerical simulations of syngas/air auto-ignition. A number of parametric test cases, by varying the turbulent Damköhler and Reynolds numbers, are considered. The auto-ignition phenomena are characterized by analyzing the corresponding heat release rates and resultant combustion modes. It is demonstrated that the observed ignition behaviors are consistent with the regime diagram predictions.
In the second part of the dissertation, applicability of a Reynolds-Averaged Navier Stokes based spray-interactive flamelet (SIF) combustion model to stratified LTC in direct-injection compression ignition (DICI) engines is assessed, which incorporates the interaction between spray evaporation, gas-phase combustion and turbulent mixing. A number of parametric cases are considered by way of varying the fuel start-of-injection (SOI) timing. The numerical results are validated against available experimental data for in-cylinder pressure trace and CO/NO emissions. It is shown that the SIF model performs well over a wide range of stratified conditions due to the incorporation of the effects of small-scale turbulent transport on combustion. Finally, the SIF model is employed to further investigate the impact of fuel injection parameters such as injection pressure and spray cone angle on the NO-CO trade-off of the DICI engine for the most delayed SOI timing.
Advisors/Committee Members: Im, Hong G (committee member), Wooldridge, Margaret S (committee member), Raman, Venkatramanan (committee member), Katopodes, Nikolaos D (committee member), Atreya, Arvind (committee member).
Subjects/Keywords: Combustion; Computational fluid dynamics; Modeling and simulation; Turbulence-chemistry interaction; Auto-ignition; High-efficiency engines; Mechanical Engineering; Engineering
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APA (6th Edition):
Pal, P. (2016). Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. (Doctoral Dissertation). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/120735
Chicago Manual of Style (16th Edition):
Pal, Pinaki. “Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.” 2016. Doctoral Dissertation, University of Michigan. Accessed January 23, 2021.
http://hdl.handle.net/2027.42/120735.
MLA Handbook (7th Edition):
Pal, Pinaki. “Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications.” 2016. Web. 23 Jan 2021.
Vancouver:
Pal P. Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. [Internet] [Doctoral dissertation]. University of Michigan; 2016. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/2027.42/120735.
Council of Science Editors:
Pal P. Computational Modeling and Analysis of Low Temperature Combustion Regimes for Advanced Engine Applications. [Doctoral Dissertation]. University of Michigan; 2016. Available from: http://hdl.handle.net/2027.42/120735
Penn State University
24.
Behrens, Christopher Michael.
Optimal design and operation of complex materials processing with application to microelectronics
.
Degree: 2009, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/10286
► Spatially distributed multiscale systems have been recently developed to describe transport-reaction processes for phenomena which occur across length scales that differ by several orders of…
(more)
▼ Spatially distributed multiscale systems have been recently developed to describe transport-reaction processes for phenomena which occur across length scales that differ by several orders of magnitude. The level of detail required to accurately describe the dynamic behavior of the system at smaller length scales cannot be provided by solely using a description from larger length-scales, whereas describing larger length-scale behavior using descriptions from smaller length-scale models would be infeasible due to the associated
computational overhead required. Motivated by the above, multiscale models, which combine larger and smaller-length scale models that are intimately connected, have been developed.
Continuous pressure on profit margins has resulted in the desire to improve
efficiency to reduce costs, resulting in the need for optimization procedures. Increases in
computational efficiency and optimization strategies have allowed for optimization of complex materials processing problems requiring multiscale models to be pursued. Multiscale optimization of such processes, however, is a problem with three levels of hierarchy in computation. In the lower hierarchy, potentially computationally intensive simulations may need to be performed to model the properties of interest at both smaller and larger length-scales. If bi-directional information is required, iterative convergence at all scales may be required; this serves as the intermediate hierarchy. Finally, optimization (gradient-based and black-box) algorithms require several function evaluations, which in this case is at the top of the hierarchy. With the need to perform numerous simulations, solving a multiscale optimization problem could quickly become intractable. One promising idea to circumvent this
computational intractability is to obtain the necessary information from linear interpolations whenever possible instead of using costly simulations. This is the basic idea behind in situ adaptive tabulation (ISAT). Initially used in solving combustion chemistry problems, ISAT has been subsequently extended to stochastic systems and combined with black-box optimization for maximizing uniformity and minimizing surface roughness in a gallium nitride thin-film.
Implementation and further refinement of these methods is investigated by modeling the deposition of a thin-film consisting of alternating gallium arsenide and aluminum arsenide layers (GaAs/AlAs.) This example uses macroscale “inputs” from the reactor description to determine properties such as temperature, flow rates, and concentrations, and mesoscale kinetic Monte Carlo (kMC) simulations to measure the previously characterized interfacial properties of the film. The objectives of this problem are to minimize the interfacial step-densities between GaAs and AlAs layers, while also minimizing the temperature and the time spent in-between depositing species (termed annealing time,) as well the macroscopic objective of reducing spatial non-uniformity. This problem only involves adsorption and…
Advisors/Committee Members: Antonios Armaou, Thesis Advisor/Co-Advisor, Antonios Armaou, Thesis Advisor/Co-Advisor.
Subjects/Keywords: multiscale methods; optimization; complex materials processing; computational efficiency
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APA (6th Edition):
Behrens, C. M. (2009). Optimal design and operation of complex materials processing with application to microelectronics
. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/10286
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):
Behrens, Christopher Michael. “Optimal design and operation of complex materials processing with application to microelectronics
.” 2009. Thesis, Penn State University. Accessed January 23, 2021.
https://submit-etda.libraries.psu.edu/catalog/10286.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Behrens, Christopher Michael. “Optimal design and operation of complex materials processing with application to microelectronics
.” 2009. Web. 23 Jan 2021.
Vancouver:
Behrens CM. Optimal design and operation of complex materials processing with application to microelectronics
. [Internet] [Thesis]. Penn State University; 2009. [cited 2021 Jan 23].
Available from: https://submit-etda.libraries.psu.edu/catalog/10286.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Behrens CM. Optimal design and operation of complex materials processing with application to microelectronics
. [Thesis]. Penn State University; 2009. Available from: https://submit-etda.libraries.psu.edu/catalog/10286
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Penn State University
25.
Fang, Yizhou.
Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation.
Degree: 2018, Penn State University
URL: https://submit-etda.libraries.psu.edu/catalog/15625yxf117
► This dissertation aims at developing model-based control and estimation algorithms via Carleman approximation to improve the performance of nonlinear model predictive controller (NMPC) and nonlinear…
(more)
▼ This dissertation aims at developing model-based control and estimation algorithms via Carleman approximation to improve the performance of nonlinear model predictive controller (NMPC) and nonlinear moving horizon estimation (NMHE).
Despite the many advantages of model predictive control (MPC) and moving horizon estimation (MHE) as advanced control and estimation technologies,
computational delay is one of the most significant problems holding back their industrial applications. This dissertation addresses this problem by developing NMPC and NMHE algorithms based on Carleman approximation to improve their
computational efficiency. We also integrate other mathematics and optimization tools in our algorithms, including control vector parameterization (CVP) and nonlinear programming (NLP) sensitivity analysis, to further improve their performances.
We model the original nonlinear system with a Two-Tier approximation. First, we approximate the system through a Taylor expansion and arrive at a polynomial formulation. Second, we extend the state variables to higher orders following the Kronecker product rule. After that, we approximate the system for a second time through Carleman approximation (also known as Carleman linearization). After this Two-Tier approximation, we draw an extended bilinear expression to represent the nonlinear dynamics.
With little loss of nonlinear information, it enables analytical prediction of future system evolution.
Assuming piecewise constant control signals, the manipulated inputs are entering the cost function as parameters. Through Carleman approximation, the dynamic models are directly incorporated into the cost function, releasing the optimization from these equality constraints. This also allows the computer to analytically calculate the sensitivity of the cost function to the manipulated inputs. The analytical sensitivity facilitates the solver by serving as the search gradient, and also allows us to develop sensitivity-updating algorithms. All of these together contributes to significantly increased
computational efficiency.
We present an analysis of error accumulation caused by Carleman approximation and then improve the accuracy of this approach by resetting extended states periodically. The idea of efficient temporal discretization in CVP is embedded in the Carleman model predictive control (CMPC) formulation to improve the controller performance. The advantages are illustrated with two application examples where we solve a tracking problem and a regulation problem.
A computationally efficient approach of economic-oriented model predictive control (EMPC) is developed, Carleman EMPC. Carleman approximation works well with set-point free economic cost function. In this way, we predict the future economic performance analytically and provide the sensitivity of the economic performance to the manipulated inputs as the search gradient. Hence, despite the economic stage costs are mostly non-tracking and non-quadratic, we achieve significant acceleration in the computation of EMPC. An…
Advisors/Committee Members: Antonios Armaou, Dissertation Advisor/Co-Advisor, Antonios Armaou, Committee Chair/Co-Chair, Robert Martin Rioux Jr., Committee Member, Xueyi Zhang, Committee Member, Hosam Kadry Fathy, Outside Member.
Subjects/Keywords: model predictive control; moving horizon estimation; nonlinear control; Carleman approximation; computational efficiency; advanced process control; optimization
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APA ·
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APA (6th Edition):
Fang, Y. (2018). Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation. (Thesis). Penn State University. Retrieved from https://submit-etda.libraries.psu.edu/catalog/15625yxf117
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):
Fang, Yizhou. “Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation.” 2018. Thesis, Penn State University. Accessed January 23, 2021.
https://submit-etda.libraries.psu.edu/catalog/15625yxf117.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Fang, Yizhou. “Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation.” 2018. Web. 23 Jan 2021.
Vancouver:
Fang Y. Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation. [Internet] [Thesis]. Penn State University; 2018. [cited 2021 Jan 23].
Available from: https://submit-etda.libraries.psu.edu/catalog/15625yxf117.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Fang Y. Model-based Receding Horizon Control and Estimation for Nonlinear Systems via Carleman Approximation. [Thesis]. Penn State University; 2018. Available from: https://submit-etda.libraries.psu.edu/catalog/15625yxf117
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
26.
Machart, Pierre.
Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level.
Degree: Docteur es, Informatique, 2012, Aix Marseille Université
URL: http://www.theses.fr/2012AIXM4779
► L'Apprentissage Automatique tire ses racines d'un large champ disciplinaire qui inclut l'Intelligence Artificielle, la Reconnaissance de Formes, les Statistiques ou l'Optimisation. Dès les origines de…
(more)
▼ L'Apprentissage Automatique tire ses racines d'un large champ disciplinaire qui inclut l'Intelligence Artificielle, la Reconnaissance de Formes, les Statistiques ou l'Optimisation. Dès les origines de l'Apprentissage, les questions computationelles et les propriétés en généralisation ont toutes deux été identifiées comme centrales pour la discipline. Tandis que les premières concernent les questions de calculabilité ou de complexité (sur un plan fondamental) ou d'efficacité computationelle (d'un point de vue plus pratique) des systèmes d'apprentissage, les secondes visent a comprendre et caractériser comment les solutions qu'elles fournissent vont se comporter sur de nouvelles données non encore vues. Ces dernières années, l'émergence de jeux de données à grande échelle en Apprentissage Automatique a profondément remanié les principes de la Théorie de l'Apprentissage. En prenant en compte de potentielles contraintes sur le temps d'entraînement, il faut faire face à un compromis plus complexe que ceux qui sont classiquement traités par les Statistiques. Une conséquence directe tient en ce que la mise en place d'algorithmes efficaces (autant en théorie qu'en pratique) capables de tourner sur des jeux de données a grande échelle doivent impérativement prendre en compte les aspects statistiques et computationels de l'Apprentissage de façon conjointe. Cette thèse a pour but de mettre à jour, analyser et exploiter certaines des connections qui existent naturellement entre les aspects statistiques et computationels de l'Apprentissage.
Machine Learning is known to have its roots in a broad spectrum of fields including Artificial Intelligence, Pattern Recognition, Statistics or Optimisation. From the earliest stages of Machine Learning, both computational issues and generalisation properties have been identified as central to the field. While the former address the question of computability, complexity (from a fundamental perspective) or computational efficiency (on a more practical standpoint) of learning systems, the latter aim at understanding and characterising how well the solutions they provide perform on new, unseen data. Those last years, the emergence of large-scale datasets in Machine Learning has been deeply reshaping the principles of Learning Theory. Taking into account possible constraints on the training time, one has to deal with more complex trade-offs than the ones classically addressed by Statistics. As a direct consequence, designing new efficient algorithms (both in theory and practice), able to handle large-scale datasets, imposes to jointly deal with the statistical and computational aspects of Learning. The present thesis aims at unravelling, analysing and exploiting some of the connections that naturally exist between the statistical and computational aspects of Learning. More precisely, in a first part, we extend the stability analysis, which relates some algorithmic properties to the generalisation abilities of learning algorithms, to a novel (and fine-grain) performance measure, namely the…
Advisors/Committee Members: Ralaivola, Liva (thesis director), Glotin, Hervé (thesis director).
Subjects/Keywords: Apprentissage statistique; Théorie de l'apprentissage; Optimisation; Algorithmes; Efficacité computationelle; Statistical learning; Learning theory; Optimisation; Algorithms; Computational efficiency
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APA ·
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MLA ·
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CSE |
Export
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Manager
APA (6th Edition):
Machart, P. (2012). Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level. (Doctoral Dissertation). Aix Marseille Université. Retrieved from http://www.theses.fr/2012AIXM4779
Chicago Manual of Style (16th Edition):
Machart, Pierre. “Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level.” 2012. Doctoral Dissertation, Aix Marseille Université. Accessed January 23, 2021.
http://www.theses.fr/2012AIXM4779.
MLA Handbook (7th Edition):
Machart, Pierre. “Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level.” 2012. Web. 23 Jan 2021.
Vancouver:
Machart P. Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level. [Internet] [Doctoral dissertation]. Aix Marseille Université 2012. [cited 2021 Jan 23].
Available from: http://www.theses.fr/2012AIXM4779.
Council of Science Editors:
Machart P. Coping with the computational and statistical bipolar nature of machine learning : Explicit and implicit stereotyping of trisomy 21. Relationships between typicality of faces, judgment of intelligence and cognitive level. [Doctoral Dissertation]. Aix Marseille Université 2012. Available from: http://www.theses.fr/2012AIXM4779
Delft University of Technology
27.
Fortich Mora, F.E. (author).
Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models.
Degree: 2020, Delft University of Technology
URL: http://resolver.tudelft.nl/uuid:d6d3d3e6-6424-4650-88e2-8d741112257f
► As urbanization increases around the world, high-rise buildings will continue to become a more prevailing typology, nonetheless, due in part to cumbersome computational simulations, rarely…
(more)
▼ As urbanization increases around the world, high-rise buildings will continue to become a more prevailing typology, nonetheless, due in part to cumbersome computational simulations, rarely do designers have enough information during the early stages of design, which is the time when their choices affect the most the efficiency of their building. Surrogate models, aka meta-models that predict how the original simulation models behave offer a clear advantage in terms of speed of the results. This study delves into performance-based design using surrogate models to give the designer a tool to quickly understand the variables that will affect its efficiency. Looking specifically to improve four (4) results: energy consumption, natural daylight, comfort, and floor area. This study contemplates 16 unique variables ranging from effects of the Context (1), general building shape & orientation (6) to façade variables (9). The energy results are validated in DesignBuilder software before proceeding to collect 500 samples for two different locations: Bogotá and Amsterdam. This data is then run through three machine learning methods, Multilinear Regression, Non-linear Regression, and ANN. Next, the chosen ANN-based surrogate models for each of the outcomes are trained and hyperparameters finetuned to increase their R2 value and reduce their standard error (MSE) and mean absolute error (MAE). Finally, the generic surrogate models are run and compared through various optimization algorithms to determine Pareto-frontier options that ultimately improve the energy performance of a solution with the daylight, comfort, and floor area as design constraints or goals. A time reduction of up to 99.96% was achieved to collect another 500 samples. Finally, the final model also serves as an aid for visualization of the design space by allowing near-real-time (6 seconds) to generate the form of each design solution
Architecture, Urbanism and Building Sciences | Building Technology - Sustainable Design
Advisors/Committee Members: Turrin, M. (mentor), Ekici, B. (mentor), Bokel, R.M.J. (mentor), Delft University of Technology (degree granting institution).
Subjects/Keywords: High-Rise; Performance based design; Surrogate modelling; Energy Efficiency; Daylight; Comfort; Machine Learning; Computational Optimization; Artificial Neural Networks; Sampling
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APA (6th Edition):
Fortich Mora, F. E. (. (2020). Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models. (Masters Thesis). Delft University of Technology. Retrieved from http://resolver.tudelft.nl/uuid:d6d3d3e6-6424-4650-88e2-8d741112257f
Chicago Manual of Style (16th Edition):
Fortich Mora, F E (author). “Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models.” 2020. Masters Thesis, Delft University of Technology. Accessed January 23, 2021.
http://resolver.tudelft.nl/uuid:d6d3d3e6-6424-4650-88e2-8d741112257f.
MLA Handbook (7th Edition):
Fortich Mora, F E (author). “Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models.” 2020. Web. 23 Jan 2021.
Vancouver:
Fortich Mora FE(. Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models. [Internet] [Masters thesis]. Delft University of Technology; 2020. [cited 2021 Jan 23].
Available from: http://resolver.tudelft.nl/uuid:d6d3d3e6-6424-4650-88e2-8d741112257f.
Council of Science Editors:
Fortich Mora FE(. Humble Giants: Computational Intelligence for Designing More Sustainable High-rise Buildings using Surrogate Models. [Masters Thesis]. Delft University of Technology; 2020. Available from: http://resolver.tudelft.nl/uuid:d6d3d3e6-6424-4650-88e2-8d741112257f
Colorado State University
28.
Wilson, Jordan M.
Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics.
Degree: MS(M.S.), Civil and Environmental Engineering, 2011, Colorado State University
URL: http://hdl.handle.net/10217/47425
► This study focuses on the evaluation of flow and scalar transport characteristics of small disinfection systems, primarily through computational fluid dynamics (CFD) as well as…
(more)
▼ This study focuses on the evaluation of flow and scalar transport characteristics of small disinfection systems, primarily through
computational fluid dynamics (CFD) as well as physical conservative tracer studies. Original research was performed on a pipe loop, series of pressurized tanks, and two separate open surface tank contact systems and a case study was performed on a baffled tank system. The flow dynamics for each of these respective disinfection systems were evaluated using CFD. The flow dynamics govern the transport of any quantity (e.g., a passive scalar, conservative tracer, or chlorine-containing species) through the system visualized through plotting the effluent concentration (e.g., passive scalar for
computational models and conservative tracer for physical experiments) through time forming what is commonly referred to as a residence time distribution (RTD), or flow-through, curve. Physical experiments provided validation for the CFD models that give a more complete view of hydraulic
efficiency thus overcoming the common "black-box" approach to contact tank design using only the theoretical detention time (TDT) (defined as the system volume V divided by the volumetric flow rate Q). The differing geometries of contact tank systems yield significantly different flow paths with varying degrees of separation, recirculation, inlet and outlet effects, and wall effects prompting the need for the evaluation of hydraulic
efficiency to be unique to the system. Yet current practice evaluates the hydraulic
efficiency of disinfection contact tank systems based on the TDT and the rising limb of the RTD curve, designated by the United States Environmental Protection Agency (USEPA) as baffle factor (BF). Research presented in this study using CFD models and physical tracer studies shows that evaluation methods based upon TDT tend to overestimate, severely in some instances, the actual hydraulic
efficiency as obtained from the systems' flow and scalar transport dynamics and subsequent RTD curves. The main objectives of this study were to determine the systems' respective hydraulic efficiencies and to analyze an alternative measure of hydraulic
efficiency, the ratio t10/t90, where t10 and t90 are the time taken for 10 and 90 percent of the input concentration to be observed at the outlet of a system. The pipe loop system was dominated by advection and thus showed little variance in the values of BF and t10/t90. Analysis of the series of pressurized tank systems showed significant regions of turbulent mixing and recirculation corresponding to a system that was much less efficient than the pipe loop system. BF values for the pressurized tank systems were nearly 100 percent greater than t10/t90 values as a result of a system behavior further from plug flow. The open surface tank systems exhibited the most uneven flow paths and lowest efficiencies seen in this study with BF and t10/t90 values differing by at least 100 percent. These systems exhibited significant degrees of short-circuiting and recirculation largely due to…
Advisors/Committee Members: Venayagamoorthy, S. Karan (advisor), Gates, Timothy K. (committee member), Wickramasinghe, S. Ranil (committee member).
Subjects/Keywords: contact tanks; small public water disinfection system; residence time distribution curve; hydraulic efficiency; baffle factor; computational fluid dynamics
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APA ·
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APA (6th Edition):
Wilson, J. M. (2011). Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics. (Masters Thesis). Colorado State University. Retrieved from http://hdl.handle.net/10217/47425
Chicago Manual of Style (16th Edition):
Wilson, Jordan M. “Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics.” 2011. Masters Thesis, Colorado State University. Accessed January 23, 2021.
http://hdl.handle.net/10217/47425.
MLA Handbook (7th Edition):
Wilson, Jordan M. “Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics.” 2011. Web. 23 Jan 2021.
Vancouver:
Wilson JM. Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics. [Internet] [Masters thesis]. Colorado State University; 2011. [cited 2021 Jan 23].
Available from: http://hdl.handle.net/10217/47425.
Council of Science Editors:
Wilson JM. Evaluation of flow and scalar transport characteristics of small public drinking water disinfection systems using computational fluid dynamics. [Masters Thesis]. Colorado State University; 2011. Available from: http://hdl.handle.net/10217/47425
University of Manchester
29.
Salih, Sarmed Abdalrasoul.
RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE.
Degree: 2018, University of Manchester
URL: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314043
► Despite the phenomena of fracture and fatigue having been the focus of academic research for more than 150 years, it remains in effect an empirical…
(more)
▼ Despite the phenomena of fracture and fatigue
having been the focus of academic research for more than 150 years,
it remains in effect an empirical science lacking a complete and
comprehensive set of predictive solutions. In this regard, the
focus of the research in this thesis is on the development of new
cohesive-zone models for fracture and fatigue that are afforded an
ability to capture strain-rate effects. For the case of monotonic
fracture in ductile material, different combinations of material
response are examined with rate effects appearing either in the
bulk material or localised to the cohesive-zone or in both. The
development of a new rate-dependent CZM required first an analysis
of two existing methods for incorporating rate dependency,
i.e.either via a temporal critical stress or a temporal critical
separation. The analysis revealed unrealistic crack behaviour at
high loading rates. The new rate-dependent cohesive model
introduced in the thesis couples the temporal responses of critical
stress and critical separation and is shown to provide a stable and
realistic solution to dynamic fracture. For the case of fatigue, a
new frequency-dependent cohesive-zone model (FDCZM) has been
developed for the simulation of both high and low-cycle
fatigue-crack growth in elasto-plastic material. The developed
model provides an alternative approach that delivers the accuracy
of the loading-unloading hysteresis damage model along with the
computational efficiency of the equally well-established envelope
load-damage model by incorporating a fast-track feature. With the
fast-track procedure, a particular damage state for one loading
cycle is “frozen in†over a predefined number of cycles. Stress
and strain states are subsequently updated followed by an update on
the damage state in the representative loading cycle which again is
“frozen in†and applied over the same number of cycles. The
process is repeated up to failure. The technique is shown to be
highly efficient in terms of time and cost and is particularly
effective when a large number of frozen cycles can be applied
without significant loss of accuracy. To demonstrate the practical
worth of the approach, the effect that the frequency has on fatigue
crack growth in austenitic stainless-steel 304 is analysed. It is
found that the crack growth rate (ð‘‘ð‘Žð‘‘ð‘â„) decreases with
increasing frequency up to a frequency of 5 Hz after which it
levels off. The behaviour, which can be linked to martensitic phase
transformation, is shown to be accurately captured by the new
FDCZM.
Advisors/Committee Members: ZOU, ZHENMIN Z, Davey, Keith, Zou, Zhenmin.
Subjects/Keywords: Cohesive zone model; Traction-separation law; Dynamic loading; Rate dependency; UMAT subroutine; Fatigue crack growth modelling; computational efficiency; frequency dependence
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APA ·
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MLA ·
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Manager
APA (6th Edition):
Salih, S. A. (2018). RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE. (Doctoral Dissertation). University of Manchester. Retrieved from http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314043
Chicago Manual of Style (16th Edition):
Salih, Sarmed Abdalrasoul. “RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE.” 2018. Doctoral Dissertation, University of Manchester. Accessed January 23, 2021.
http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314043.
MLA Handbook (7th Edition):
Salih, Sarmed Abdalrasoul. “RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE.” 2018. Web. 23 Jan 2021.
Vancouver:
Salih SA. RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE. [Internet] [Doctoral dissertation]. University of Manchester; 2018. [cited 2021 Jan 23].
Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314043.
Council of Science Editors:
Salih SA. RATE-DEPENDENT COHESIVE-ZONE MODELS FOR FRACTURE AND
FATIGUE. [Doctoral Dissertation]. University of Manchester; 2018. Available from: http://www.manchester.ac.uk/escholar/uk-ac-man-scw:314043
Linköping University
30.
Olofsson, Karl-Johan.
Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures.
Degree: Mathematics, 2019, Linköping University
URL: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162235
► Microsized hexagonal gallium nitride pyramids show promise as next generation Light Emitting Diodes (LEDs) due to certain quantum properties within the pyramids. One metric…
(more)
▼ Microsized hexagonal gallium nitride pyramids show promise as next generation Light Emitting Diodes (LEDs) due to certain quantum properties within the pyramids. One metric for evaluating the efficiency of a LED device is by studying its Light Extraction Efficiency (LEE). To calculate the LEE for different pyramid designs, simulations can be performed using the FDTD method. Maximizing the LEE is treated as a black-box optimization problem with an interpolation method that utilizes radial basis functions. A simple heuristic is implemented and tested for various pyramid parameters. The LEE is shown to be highly dependent on the pyramid size, the source position and the polarization. Under certain circumstances, a LEE over 17% is found above the pyramid. The results are however in some situations very sensitive to the simulation parameters, leading to results not converging properly. Establishing convergence for all simulation evaluations must be done with further care. The results imply a high LEE for the pyramids is possible, which motivates the need for further research.
Subjects/Keywords: Black-box optimization; Radial basis functions; Gallium nitride; light extraction efficiency; FDTD; surrogate functions; semiconductors; global optimization; Computational Mathematics; Beräkningsmatematik
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Record Details
Similar Records
Cite
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❌
APA ·
Chicago ·
MLA ·
Vancouver ·
CSE |
Export
to Zotero / EndNote / Reference
Manager
APA (6th Edition):
Olofsson, K. (2019). Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures. (Thesis). Linköping University. Retrieved from http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162235
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):
Olofsson, Karl-Johan. “Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures.” 2019. Thesis, Linköping University. Accessed January 23, 2021.
http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162235.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
MLA Handbook (7th Edition):
Olofsson, Karl-Johan. “Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures.” 2019. Web. 23 Jan 2021.
Vancouver:
Olofsson K. Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures. [Internet] [Thesis]. Linköping University; 2019. [cited 2021 Jan 23].
Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162235.
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
Council of Science Editors:
Olofsson K. Black-box optimization of simulated light extraction efficiency from quantum dots in pyramidal gallium nitride structures. [Thesis]. Linköping University; 2019. Available from: http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-162235
Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation
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Open Access Theses and Dissertations