Parameter extraction in organic thin film transistors (OTFTs) is a labour intensive task when contact effects are present. In this work, a constrained many-objectiveevolutionary parameter extraction procedure is used...
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ISBN:
(纸本)9781538657799
Parameter extraction in organic thin film transistors (OTFTs) is a labour intensive task when contact effects are present. In this work, a constrained many-objectiveevolutionary parameter extraction procedure is used to determine the parameters of a compact model for the current-voltage characteristics of OTFTs that also includes a model for the contacts. This evolutionary procedure ensures that the extracted parameters comply with the physical meaning on which they are based by adding rules in form of optimization objectives and constrains for the different parameters. The evolutionary procedure is applied to experimental output characteristics of OTFTs. Our numerical results show an excellent agreement with the experimental data.
This paper describes the changes done to Daphne, a virtual assistant for architecting earth observing satellite systems, to turn it from a reactive assistant that only acts when asked by the user into a proactive assi...
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ISBN:
(数字)9781624105784
ISBN:
(纸本)9781624105784
This paper describes the changes done to Daphne, a virtual assistant for architecting earth observing satellite systems, to turn it from a reactive assistant that only acts when asked by the user into a proactive assistant that can perform actions without not directly linked to a user request, taking its own initiative. Specifically, the paper describes a new way for Daphne to communicate with the user with Websockets that allows for a broader range of interactivity. The new features enabled by this new communication system are: (1) an agent that searches over the space of designs and shows interesting designs to the user;(2) an agent that tries to encourage the user to diversify their search of the tradespace;and (3) a live recommender system that acts when the user is modifying a certain design by suggesting changes that are likely to improve cost and/or performance. The paper also describes changes in the existing sub-systems as well as the interface to accommodate the new systems and interactivity. Finally, the paper has a short discussion on how a common user case scenario would unfold with all these new features.
This research performs a surrogate-assisted shape optimisation of hypersonic waveriders, where the trajectories of each shape are optimised with a multi-objectiveevolutionary algorithm for heat-load and cross-range. ...
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ISBN:
(数字)9781624107115
ISBN:
(纸本)9781624107115
This research performs a surrogate-assisted shape optimisation of hypersonic waveriders, where the trajectories of each shape are optimised with a multi-objectiveevolutionary algorithm for heat-load and cross-range. A study on the best evolutionary algorithm, node control strategy for angle of attack and bank angle profiles, and population size to use in the trajectory optimisation phase, are identified. The aerodynamics of the waveriders is computed with a new local surface inclination method blending the modified Newtonian and tangent wedge solutions, while the convective heat flux is computed for the leading edges using the Newton-Kays engineering model. Shape variability is introduced according to the layout of central composite designs, and analysis of variance is applied to identify the shape features driving the two objectives. Shock angle, leading edge radius and overall vehicle dimensions are the strongest drivers, while details on the planform shape are less relevant and should be left for posterior studies. The surrogates are a good approximation of the true fitness functions, so they were optimised in a single-objective framework, producing two optimal waverider designs.
Entry, Descent, and Landing (EDL) architecture analysis relies on uncertainty quantification methods, such as Monte Carlo dispersion analysis, to assess system performance, and identify areas of risk. These simulation...
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ISBN:
(数字)9781624105951
ISBN:
(纸本)9781624105951
Entry, Descent, and Landing (EDL) architecture analysis relies on uncertainty quantification methods, such as Monte Carlo dispersion analysis, to assess system performance, and identify areas of risk. These simulations are critical throughout the entire mission lifecycle due to the inherent limitations of system verification and validation on Earth. As a mission lifecycle progresses, fidelity and complexity of these simulations increase, leading to large datasets that have to be manually examined by subject matter experts to identify correlations between parameters and calculate figures of merit. Motivated by the high cognitive load imposed by this process, this paper discusses the use of a cognitive assistant to provide a platform for interactive and collaborative explanation of EDL architecture analysis. The paper starts by describing the process of architecture analysis of EDL systems, identifying some of the main challenges leading to high cognitive workload and motivating the use of cognitive assistants. We then present a short survey of the techniques used to explain complex engineering simulations. The general architecture of the Daphne/EDL cognitive assistant is then described, focusing on the use case of explaining the results of a set of EDL simulations. Three functions are described in detail, namely 1) summarizing the statistics of large datasets (summarization), 2) identifying the input variables that appear to be driving the output variables (sensitivity analysis), and 3) identifying features and behaviors that appear to be common among failing cases or some other region of interest of the design space (association rule mining).
In this paper the case study of a smart home powered by solar and wind energy is presented. The benefits of having a smart home that can control the amount of power needed, according to the context of the usage, are a...
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ISBN:
(纸本)9781457710018
In this paper the case study of a smart home powered by solar and wind energy is presented. The benefits of having a smart home that can control the amount of power needed, according to the context of the usage, are also shown. Simulation shows that with a good control of the load it might be possible to reduce the installation costs of the Green Energy System. Furthermore, to support the results, a load balancing algorithm is created based on the Knapsack problem. An economic analysis of the approach is also shown to demonstrate the viability of the project, and how can the intelligence in the home lower the cost.
With the advancement in high performance computing and numerical optimization techniques, engineering design optimization problems are becoming more complex, larger scale, higher fidelity, and computationally more dem...
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ISBN:
(数字)9781624105784
ISBN:
(纸本)9781624105784
With the advancement in high performance computing and numerical optimization techniques, engineering design optimization problems are becoming more complex, larger scale, higher fidelity, and computationally more demanding, requiring longer run times than ever before. There exists methodologies and techniques that can address some of these challenges but very few can address all, and most are limited in the extent that these concerns can be addressed. With the goal of addressing such challenging engineering problems, we developed a new optimization algorithm, named AMIEGO, that combines concepts from surrogate-based optimization approaches, gradient-based numerical methods, Partial Least Squares, evolutionaryalgorithms, and Branch-and-Bound, providing newer capabilities that were not previously perceived. The effort here builds upon this previously developed optimization algorithm to include multiple infill sampling capability that combines the concept of generalized expected improvement function, unsupervised learning, and multi-objectiveevolutionary technique. To demonstrate, AMIEGO with the multiple infill capability (called AMIEGO-MIMOS) solves a series of increasingly difficult engineering design optimization problems. The results reveal the performance of the new approach is problem dependent. When applied to a ten-bar truss problem, the newly proposed multiple infill strategy consistently leads to a better design solutions when compared to the existing CPTV method (implemented with the context of the AMIEGO algorithm). On the other hand, when applied to a mixed-integer high fidelity wing topology optimization problem - MIMOS, despite showing a steeper convergence at the start, eventually leads to an inferior solution as compared to CPTV approach. These results also reveal that a small number of starting points, in general, are sufficient to lead to a good overall solution.
In this paper the case study of a smart home powered by solar and wind energy is presented. The benefits of having a smart home that can control the amount of power needed, according to the context of the usage, are a...
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ISBN:
(纸本)9781457710001
In this paper the case study of a smart home powered by solar and wind energy is presented. The benefits of having a smart home that can control the amount of power needed, according to the context of the usage, are also shown. Simulation shows that with a good control of the load it might be possible to reduce the installation costs of the Green Energy System. Furthermore, to support the results, a load balancing algorithm is created based on the Knapsack problem. An economic analysis of the approach is also shown to demonstrate the viability of the project, and how can the intelligence in the home lower the cost.
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