Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 20 for “"Direct Transcription"”.
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Dynamic system design optimization of wave energy converters utilizing direct transcription
… A particular class of numerical methods known as direct transcription is identified as promising solution method. These principles are then demonstrated on the design of a wave energy converter, a device that captures energy present in ocean waves. This system is of particular interest since a …
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Optimal finite-thrust spacecraft trajectories using direct transcription and nonlinear programming
… numerically. This conversion is referred to as ""transcription."" Transcription methods were developed in the sixties and seventies; however, for nonlinear problems, they were used in conjunction with a ""state-elimination"" procedure which propagated the integration forward over the trajectory, …
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Automated planetary satellite tour planning with a novel low-thrust direct transcription method
… numerical optimizer employing the Sims-Flanagan transcription method. To illustrate the difficulty of low-thrust trajectory optimization in a dynamical system characterized by a short time scale, and to provide an example of a tool that would benefit from the previously mentioned improvements, an …
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Rigid Body Constrained Motion Optimization and Control on Lie Groups and Their Tangent Bundles
… and optimal controls problems through direct transcription offers a reduction in the number of constraints imposed on the problem. The on-manifold optimization methodologies are applied to the Lie groups listed above. Then, the direct transcription of the optimal control and trajectory …
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A new numerical optimization method based on Taylor series for challenging trajectory optimization problems
… problems are devised. The methods use direct transcription to convert the continuous optimal control problem into a parameter optimization problem that can be solved with non-linear programming. In direct transcription the system equations must be converted into algebraic constraints. …
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Optimal control of wave energy converters
… control problem for WECs in the framework of direct transcription methods, known as spectral and pseudospectral optimal control. Direct transcription methods transform continuous time optimal control problems into Non Linear Programming (NLP) problems, for which the literature (and the market) …
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Advances in combined architecture, plant, and control design
… with a detailed discussion of the two methods. Direct transcription is also discussed as it enables the solution of general co-design problems by approximating the problem. Motivated primarily by the need for efficient methods to solve certain control problems that emerge using the nested …
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Constrained Optimization on SO(3), via Pseudospectral Collocation
<p>Pseudospectral collocation is a widely used direct transcription method that discretizes continuous systems with spectral accuracy and high fidelity while requiring relatively few collocation points. The special orthogonal group, SO(3), is both a Lie group and a manifold, and thus demands …
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Analysis of the Structure and Cell-Specific Transcription of the Bovine Parathyroid Hormone Gene (Micrococcal Nuclease)
… mRNA indicate that both TATA boxes function in directing transcription in vivo. In addition, both TATA boxes appear to direct transcription in vitro. However, the relative levels of transcriptional initiation from the two TATA boxes were different in vitro as compared to in vivo.
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On generating driving trajectories in urban traffic to achieve higher fuel efficiency
… along the time horizon. Then, we turn to Direct Transcription with RK4 Steps and Parallel Shooting (DTRPS) with which we translate the minimization problem to a nonlinear programming (NLP) problem. We also include an extensive case study for a door-to-door trip with differ- ent traveling …
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A Gauss pseudospectral transcription for optimal control
… is proposed in this thesis. The method is a direct transcription that transcribes the continuous optimal control problem into a discrete nonlinear programming problem (NLP), which can be solved by well-developed algorithms. The method is based on using global polynomial approximations to the …
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Advancement and analysis of Gauss pseudospectral transcription for optimal control problems
… numerical methods are needed to solve them. Direct transcription methods, and in particular, methods involving orthogonal collocation have become quite popular in several field areas due to their high accuracy in approximating non-analytic solutions with relatively few discretization points. …
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Application of robust nonlinear model predictive control to simulating the control behaviour of a racing driver
… its robustness. Full nonlinear optimisation with direct transcription is used to derive a controller that can stabilise a vehicle at the handling limit under the action of disturbances. The careful choice of discretisation method and track description allow for reduced computing times. The …
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Automated Design of Multiphase Space Missions Using Hybrid Optimal Control
… control history. Genetic algorithms (GA) and direct transcription with nonlinear programming (NLP) are introduced as methods of solution for the outer-loop and inner-loop problems, respectively. Automation of the inner-loop, continuous optimal control problem solver, required two new …
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Transcription regulation in Plasmodium falciparum : functional characterisation of general transcription factor IIB
… In eukaryotes, regulation of RNA Polymerase II transcription initiation is one of the main mechanism of gene expression control. Past research has revealed the presence of crucial elements of RNA Polymerase II (RNAPII) transcription machinery in P. falciparum, however, the precise transcription …
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Chondrocyte Regulation by IL-I and IGF-I: Interconnection Between Anabolic and Catabolic Factors
… of the IGF-I system occurs through both direct (transcription) and indirect (proteolysis) mechanisms. These results have implications for molecular therapies (e.g., gene transfer) directed at reversing osteoarthritic cartilage deterioration. The presented research concerns not only …
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Design of genetic regulatory networks
… for gene circuit design. The first is based on direct transcription (DT) and mathematical programs with complementarity constraints (MPCCs). Since genetic regulatory networks are dynamic systems, DT is an appropriate optimization strategy, and is used to determine optimal network parameter …
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Characterization of Genome-Wide Binding of NUCLEAR-FACTOR I-X in Hematopoietic Progenitor Cells
… NFIX-FLAG was capable of binding to and transcriptionally activating a proximal c-Mpl promoter fragment. In sum, these data suggest that NFIX-mediated up-regulation of c-Mpl transcription can protect primitive hematopoietic cells from stress ex vivo. Understanding the direct …
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Cloning and characterization of ovine insulin, insulin-like growth factor-I and -II genes
… in exon 3. Using primer extension, the ovine transcription initiation sites were mapped and found to be well conserved among mammalian and avian IGF-I genes. Expression of exon 1-, 2- and W-specific transcripts was examined in seven tissues from adult or fetal sheep using a reverse …
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Automated trajectory planning for multiple-flyby interplanetary missions
… flight times between planets, magnitudes and directions of thrust, flyby altitudes, etc. The contribution of this work is a framework for the autonomous optimization of multiple-flyby interplanetary trajectories. The trajectory design problem is converted into a HOCP with two nested loops: an …