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1 
Algorithms for large sparse constrained optimisationHernandez, Marli de Freitas Gomes January 1995 (has links)
No description available.

2 
Clock Distribution Network Optimization by Sequential Quadratic ProgramingMekala, Venkata 2010 May 1900 (has links)
Clock mesh is widely used in microprocessor designs for achieving low clock
skew and high process variation tolerance. Clock mesh optimization is a very diffcult
problem to solve because it has a highly connected structure and requires accurate
delay models which are computationally expensive.
Existing methods on clock network optimization are either restricted to clock
trees, which are easy to be separated into smaller problems, or naive heuristics based
on crude delay models.
A clock mesh sizing algorithm, which is aimed to minimize total mesh wire area
with consideration of clock skew constraints, has been proposed in this research work.
This algorithm is a systematic solution search through rigorous Sequential Quadratic
Programming (SQP). The SQP is guided by an efficient adjoint sensitivity analysis
which has nearSPICE(Simulation Program for Integrated Circuits Emphasis)level
accuracy and fasterthanSPICE speed.
Experimental results on various benchmark circuits indicate that this algorithm
leads to substantial wire area reduction while maintaining low clock skew in the clock
mesh. The reduction in mesh area achieved is about 33%.

3 
Neural Network Based Cogeneration Dispatch nder DeregulationChou, Yuching 03 August 2005 (has links)
Cogeneration is an efficient energy system that generates steam and electricity simultaneously. In ordinary operation, fuel cost accounts for more than 60% of the operational cost. As a result, the boiler efficiency and optimization level of cogeneration are both high. To achieve further energy conservation, objectives of this thesis are to find the Profitmaximizing dispatch and efficiency enhancing strategy of the cogeneration systems under deregulation.
In a coexistent environment of both Bilateral and Poolcobased power market, there are bidbased spot dispatch, and purchases and sales agreementbased contract dispatch. For profitmaximizing dispatch, the steam of boilers, fuels and generation output will be obtained by using the SQP(Sequential Quadratic Programming ) method. In order to improve the boiler efficiency, this thesis utilizes artificial neural networks(ANN) and evolutionary programming(EP) methods to search for the optimal operating conditions of boilers.
A cogeneration system (backpressure type and extraction type) is used to illustrate the effectiveness of the proposed method.

4 
Trade Study of Decomissioning Strategies for the International Space StationHerbort, Eric 06 September 2012 (has links)
This thesis evaluates decommissioning strategies for the International Space Station ISS. A permanent solution is attempted by employing energy efficient invariant manifolds that arise in the circular restricted three body problem CRTBP to transport the ISS from its low Earth orbit LEO to a lunar orbit. Although the invariant manifolds provide efficient transport, getting the the ISS onto the manifolds proves quite expensive, and the trajectories take too long to complete. Therefore a more practical, although temporary, solution consisting of an optimal reboost maneuver with the European Space Agency's automated transfer vehicle ATV is proposed. The optimal reboost trajectory is found using control parameterization and the sequential quadratic programming SQP algorithm. The model used for optimization takes into account the affects of atmospheric drag and gravity perturbations. The optimal reboost maneuver produces a satellite lifetime of approximately ninetyfive years using a two ATV strategy.

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Uncertainty modelling in power system state estimationAlOthman, Abdul Rahman K. January 2004 (has links)
As a special case of the static state estimation problem, the loadflow problem is studied in this thesis. It is demonstrated that the nonlinear loadflow formulation may be solved by realcoded genetic algorithms. Due to its global optimisation ability, the proposed method can be useful for offline studies where multiple solutions are suspected. This thesis presents two methods for estimating the uncertainty interval in power system state estimation due to uncertainty in the measurements. The proposed formulations are based on a parametric approach which takes in account the meter inaccuracies. A nonlinear and a linear formulation are proposed to estimate the tightest possible upper and lower bounds on the states. The uncertainty analysis, in power system state estimation, is also extended to other physical quantities such as the network parameters. The uncertainty is then assumed to be present in both measurements and network parameters. To find the tightest possible upper and lower bounds of any state variable, the problem is solved by a Sequential Quadratic Programming (SQP) technique. A new robust estimator based on the concept of uncertainty in the measurements is developed here. This estimator is known as Maximum Constraints Satisfaction (MCS). Robustness and performance of the proposed estimator is analysed via simulation of simple regression examples, D.C. and A.C. power system models.

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Supervisory Control Optimization with Sequential Quadratic Programming for Parallel Hybrid Vehicle with Synchronous Power SourcesJanuary 2017 (has links)
abstract: The thesis covers the development and modeling of the supervisory hybrid controller using two different methods to achieve realworld optimization and power split of a parallel hybrid vehicle with a fixed shaft connecting the Internal Combustion Engine (ICE) and Electric Motor (EM). The first strategy uses a rule based controller to determine modes the vehicle should operate in. This approach is well suited for realworld applications. The second approach uses Sequential Quadratic Programming (SQP) approach in conjunction with an Equivalent Consumption Minimization Strategy (ECMS) strategy to keep the vehicle in the most efficient operating regions. This latter method is able to operate the vehicle in various drive cycles while maintaining the SOC within allowed charge sustaining (CS) limits. Further, the overall efficiency of the vehicle for all drive cycles is increased. The limitation here is the that process is computationally expensive; however, with advent of the low cost high performance hardware this method can be used for the hybrid vehicle control. / Dissertation/Thesis / Masters Thesis Engineering 2017

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Programação quadratica sequencial e condições de qualificação / Sequential quadratic programming and constraint qualificationNunes, Fernanda Téles 03 September 2009 (has links)
Orientador: Maria Aparecida Diniz Ehrhardt / Dissertação (mestrado)  Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica / Made available in DSpace on 20180813T08:54:50Z (GMT). No. of bitstreams: 1
Nunes_FernandaTeles_M.pdf: 2400651 bytes, checksum: 206dfad35642a33d2de362510094e78d (MD5)
Previous issue date: 2009 / Resumo: Abordando problemas de minimização de funções com restrições nos deparamos com as condições de otimalidade e, ainda, com condições de qualificação das restrições. Nosso interesse é o estudo detalhado de várias condições de qualificação, com destaque para a condição de dependência linear positiva constante, e sua influência na convergência de algoritmos de Programação Quadrática Sequencial. A relevância deste estudo está no fato de que resultados de convergência que têm, em suas hipóteses, condições de qualificação fracas são mais fortes que aqueles baseados em condições de qualificação fortes. Experimentos numéricos serão realizados tanto para investigar a eficiência destes métodos na resolução de problemas com diferentes condições de qualificação, quanto para comparar dois diferentes tipos de busca, monótona e nãomonótona. Tentamos confirmar a hipótese de que algoritmos baseados em uma busca nãomonótona atuam contra o Efeito: Maratos, de comum ocorrência na resolução de problemas de minimização através de métodos de Programação Quadrática Sequencial. / Abstract: In the context of constrained optimization problems, we face the optimality conditions and also constraint qualification. Our aim is to study with details several constraint qualification, highlighting the constant positive linear dependence condition, and its influence in Sequential Quadratic Programming algorithms convergence. The relevance of this study is in the fact that convergence results having as hypothesis weak constraints qualification are stronger than those based on stronger constraints qualification. Numerical experiments will be done with the purpose of investigating the efficiency of these methods to solve problems with different constraints qualification and to compare two diferent kinds of line search, monotone and nonmonotone. We want to confirm the hypothesis that algorithms based on a nonmonotone line search act against the Maratos Effect, very common while solving minimization problems through Sequential Quadratic Programming methods. / Mestrado / Mestre em Matemática Aplicada

8 
OPTIMIZATION FOR STRUCTURAL EQUATION MODELING: APPLICATIONS TO SUBSTANCE USE DISORDERSZahery, Mahsa 01 January 2018 (has links)
Substance abuse is a serious issue in both modern and traditional societies. Besides health complications such as depression, cancer and HIV, social complications such as loss of concentration, loss of job, and legal problems are among the numerous hazards substance use disorder imposes on societies. Understanding the causes of substance abuse and preventing its negative effects continues to be the focus of much research.
Substance use behaviors, symptoms and signs are usually measured in form of ordinal data, which are often modeled under threshold models in Structural Equation Modeling (SEM). In this dissertation, we have developed a general nonlinear optimizer for the software package OpenMx, which is a SEM package in widespread use in the fields of psychology and genetics. The optimizer solves nonlinearly constrained optimization problems using a Sequential Quadratic Programming (SQP) algorithm. We have tested the performance of our optimizer on ordinal data and compared the results with two other optimizers (implementing SQP algorithm) available in the OpenMx package. While all three optimizers reach the same minimum, our new optimizer is faster than the other two.
We then applied OpenMx with our optimization engine to a very large populationbased drug abuse dataset, collected in Sweden from over one million pairs, to investigate the effects of genetic and environmental factors on liability to drug use.
Finally, we investigated the reasons behind better performance of our optimizer by profiling all three optimizers as well as analyzing their memory consumption. We found that objective function evaluation is the most expensive task for all three optimizers, and that our optimizer needs fewer number of calls to this function to find the minimum. In terms of memory consumption, the optimizers use the same amount of memory.

9 
Optimization Techniques Exploiting Problem Structure: Applications to Aerodynamic DesignShenoy, Ajit R. 11 April 1997 (has links)
The research presented in this dissertation investigates the use of allatonce methods applied to aerodynamic design. Allatonce schemes are usually based on the assumption of sufficient continuity in the constraints and objectives, and this assumption can be troublesome in the presence of shock discontinuities. Special treatment has to be considered for such problems and we study several approaches.
Our allatonce methods are based on the Sequential Quadratic Programming method, and are designed to exploit the structure inherent in a given problem. The first method is a Reduced Hessian formulation which projects the optimization problem to a lower dimension design space. The second method exploits the sparse structure in a given problem which can yield significant savings in terms of computational effort as well as storage requirements. An underlying theme in all our applications is that careful analysis of the given problem can often lead to an efficient implementation of these allatonce methods.
Chapter 2 describes a nozzle design problem involving onedimensional transonic flow. An initial formulation as an optimal control problem allows us to solve the problem as as twopoint boundary problem which provides useful insight into the nature of the problem. Using the Reduced Hessian formulation for this problem, we find that a conventional CFD method based on shock capturing produces poor performance. The numerical difficulties caused by the presence of the shock can be alleviated by reformulating the constraints so that the shock can be treated explicitly. This amounts to using a shock fitting technique. In Chapter 3, we study variants of a simplified temperature control problem. The control problem is solved using a sparse SQP scheme. We show that for problems where the underlying infinitedimensional problem is wellposed, the optimizer performs well, whereas it fails to produce good results for problems where the underlying infinitedimensional problem is illposed. A transonic airfoil design problem is studied in Chapter 4, using the Reduced SQP formulation. We propose a scheme for performing the optimization subtasks that is based on an Euler Implicit time integration scheme. The motivation is to preserve the solutionfinding structure used in the analysis algorithm. Preliminary results obtained using this method are promising. Numerical results have been presented for all the problems described. / Ph. D.

10 
Application of Genetic Algorithm to a Forced Landing Manoeuvre on Transfer of Training AnalysisTong, Peter, mail@petertong.com January 2007 (has links)
This study raises some issues for training pilots to fly forced landings and examines the impact that these issues may have on the design of simulators for such training. It focuses on flight trajectories that a pilot of a singleengine general aviation aircraft should fly after engine failure and how pilots can be better simulator trained for this forced landing manoeuvre. A sensitivity study on the effects of errors and an investigation on the effect of tolerances in the aerodynamic parameters as prescribed in the Manual of Criteria for the Qualification of Flight Simulators have on the performance of flight simulators used for pilot training was carried out. It uses a simplified analytical model for the Beech Bonanza model E33A aircraft and a vertical atmospheric turbulence based on the MILF8785C specifications. It was found that the effect of the tolerances is highly sensitive on the nature of the manoeuvre flown and that in some cases, negative transfe r of training may be induced by the tolerances. A forced landing trajectory optimisation was carried out using Genetic Algorithm. The forced landing manoeuvre analyses with preselected touchdown locations and preselected final headings were carried out for an engine failure at 650 ft AGL for bank angles varying from banking left at 45° to banking right at 45°, and with an aircraft's speed varying from 75.6 mph to 208 mph, corresponding to 5% above airplane's stall speed and airplane's maximum speed respectively. The results show that certain preselected touchdown locations are more susceptible to horizontal wind. The results for the forced landing manoeuvre with a preselected location show minimal distance error while the quality of the results for the forced landing manoeuvre with a preselected location and a final heading show that the results depend on the end constraints. For certain preselected touchdown locations and final headings, the airplane may either touchdown very close to the preselected touchdown location but with greater final h eading error from the preselected final heading or touchdown with minimal final heading error from the preselected final heading but further away from the preselected touchdown location. Analyses for an obstacle avoidance forced landing manoeuvre were also carried out where an obstacle was intentionally placed in the flight path as found by the GA program developed for without obstacle. The methodology developed successfully found flight paths that will avoid the obstacle and touchdown near the preselected location. In some cases, there exist more than one ensemble grouping of flight paths. The distance error depends on both the preselected touchdown location and where the obstacle was placed. The distance error tends to increase with the addition of a specific final heading requirement for an obstacle avoidance forced landing manoeuvre. As with the case without specific final heading requirement, there is a trade off between touching down nearer to the preselected location and touching down with a smaller final heading error.

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