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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
61

Inspiration by Nature: Biomimetic Research Informs Adaptable Building Skin System for Natural Ventilation and Daylight in Hot Dry Climate (Yazd, Iran)

Navidi, Parisa 01 January 2014 (has links) (PDF)
Many plant species, including Barrel Cacti, have developed long-term evolutionary adaptable traits to survive in extreme climates. The most important trait of cacti in extreme hot dry climates is to reduce water evaporation and increase water storage. The exterior skin of a cactus plays an important role in preventing water evaporation through heat transmission. On the other hand, there have been many passive design strategies applied to the space planning and building design of architecture in hot dry climates. The goal of these passive design strategies is to regulate the penetration of heat into building spaces while creating a strong ventilation system to help bring cool air inside the building. In this paper, adaptations of the Barrel Cactus' exterior skin, along with architectural passive design strategies for hot dry climates (in this caseYazd, Iran) will be discussed and integrated with one another through the concept of Biomimicry. The goal is to design an exterior building skin that is attuned to the environmental conditions of a hot dry climate, based on the successful applicable behaviors demonstrated in the Barrel Cactus. Key architectural features such as natural ventilation and daylight will be informed by the evolutionary cacti adaptations and passive architectural strategies in the design of the building skin in order to increase the possibility of consistent comfort for users of an office building.
62

Adaptive, adaptable, and mixed-initiative in interactive systems: An empirical investigation. An empirical investigation to examine the usability issues of using adaptive, adaptable and mixed-iniative approaches in interactive systems.

Al Omar, Khalid H. January 2009 (has links)
This thesis investigates the use of static, adaptive, adaptable and mixed-initiative approaches to the personalisation of content and graphical user interfaces (GUIs). This empirical study consisted of three experimental phases. The first examined the use of static, adaptive, adaptable and mixed-initiative approaches to web content. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) of an e-commerce website. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The second experiment examined the use of adaptive, adaptable and mixed-initiative approaches to GUIs. More specifically, it measured the usability (efficiency, frequency of error occurrence, effectiveness and satisfaction) in GUI control structures (menus). In addition, it investigated empirically the effects of content size on five different personalised menu types. In order to carry out this comparative investigation, two independent experiments were conducted, on small menus (17 items) and large ones (29 items) respectively. The experiment was conducted with 60 subjects and was tested empirically by four independent groups (15 subjects each). The third experiment was conducted with 40 subjects and was tested empirically by four dependent groups (5 subjects each). The aim of the third experiment was to mitigate the drawbacks of the adaptive, adaptable and mixedinitiative approaches, to improve their performance and to increase their usability by using multimodal auditory solutions (speech, earcons and auditory icons). The results indicate that the size of content affects the usability of personalised approaches. In other words, as the size of content increases, so does the need of the adaptive and mixed-initiative approaches, whereas that of the adaptable approach decreases. A set of empirically derived guidelines were also produced to assist designers with the use of adaptive, adaptable and mixed-initiative approaches to web content and GUI control structure.
63

Anticipating Change: Integrating Off-Site Fabrication With Adaptable Design Strategies

Parsley, Christopher M. 14 July 2009 (has links)
No description available.
64

Human Computer Interaction Design for Assisted Bridge Inspections via Augmented Reality

Smith, Alan Glynn 03 June 2024 (has links)
To address some of the challenges associated with aging bridge infrastructure, this dissertation explores the development and evaluation of a novel tool for bridge inspections leveraging Augmented Reality (AR) and computer vision (CV) technologies to facilitate measurements. Named the Wearable Inspection Report Management System (WIRMS), the system supports various data entry methods and an adaptable automation workflow for defect measurements, showcasing AR's potential to improve bridge inspection efficiency and accuracy. Within this context, the work's main research goal is to understand the difference in performance between traditional field data collection methods (i.e. pen and paper) and automated methods like spoken data entry and CV-based structural defect measurements. In case of CV assistance, emphasis was placed on human-computer interaction (HCI) to understand whether partial, collaborative automation could address some of the limitations of fully automated inspection methods. The project began with comprehensive data collection through interviews, surveys, and observations at bridge sites, which informed the creation of a Virtual Reality (VR) prototype. An initial user study tested the feasibility of using voice commands for data entry in the AR environment but found it impractical. A second user study focused on optimizing interaction methods for virtual concrete crack measurements by testing different degrees of automated CV assistance. As part of this effort, major technical contributions were made to back-end technologies and CV algorithms to improve human-machine collaboration and ensure the accuracy of measurements. Results were mixed, with larger degrees of automation resulting in significant reductions in inspection time and perceived workload, but also significant increases in the amount of measurement error. The latter result is strongly associated with a lack of field robustness of CV methods, which can under-perform if conditions are not ideal. In general, hybrid techniques which allow the user to correct CV results were seen as the most favorable. Field validations with bridge inspectors showed promising potential for practical field implementation, though further refinement is needed for broader deployment. Overall, the research establishes a viable path for making AR a central component to future inspection practices, including digital data collection, automation, data analytics, and other technologies currently in development. / Doctor of Philosophy / This dissertation investigates the development of an innovative tool designed to transform bridge inspections using Augmented Reality (AR) technology, incorporating advanced computer vision (CV) techniques to assist with measurements. The project began with thorough data collection, including interviews and observational studies at bridge sites, which directly influenced the tool's design. A prototype was initially created in a Virtual Reality (VR) environment to refine the functionalities needed for AR application. The resulting AR system supports various interactive methods for documenting and measuring bridge defects, showcasing how AR can streamline and enhance traditional bridge inspection processes. However, challenges remain, particularly in accurately measuring certain types of defects, indicating that some traditional tools are still necessary. Despite these challenges, early tests with bridge inspectors have been promising, suggesting that AR could significantly improve the efficiency and accuracy of bridge inspections. The research demonstrates a clear path forward for further development, with the potential to revolutionize how bridge inspections are conducted.
65

Aeroelasticity of Morphing Wings Using Neural Networks

Natarajan, Anand 23 July 2002 (has links)
In this dissertation, neural networks are designed to effectively model static non-linear aeroelastic problems in adaptive structures and linear dynamic aeroelastic systems with time varying stiffness. The use of adaptive materials in aircraft wings allows for the change of the contour or the configuration of a wing (morphing) in flight. The use of smart materials, to accomplish these deformations, can imply that the stiffness of the wing with a morphing contour changes as the contour changes. For a rapidly oscillating body in a fluid field, continuously adapting structural parameters may render the wing to behave as a time variant system. Even the internal spars/ribs of the aircraft wing which define the wing stiffness can be made adaptive, that is, their stiffness can be made to vary with time. The immediate effect on the structural dynamics of the wing, is that, the wing motion is governed by a differential equation with time varying coefficients. The study of this concept of a time varying torsional stiffness, made possible by the use of active materials and adaptive spars, in the dynamic aeroelastic behavior of an adaptable airfoil is performed here. A time marching technique is developed for solving linear structural dynamic problems with time-varying parameters. This time-marching technique borrows from the concept of Time-Finite Elements in the sense that for each time interval considered in the time-marching, an analytical solution is obtained. The analytical solution for each time interval is in the form of a matrix exponential and hence this technique is termed as Matrix Exponential time marching. Using this time marching technique, Artificial Neural Networks can be trained to represent the dynamic behavior of any linearly time varying system. In order to extend this methodology to dynamic aeroelasticity, it is also necessary to model the unsteady aerodynamic loads over an airfoil. Accordingly, an unsteady aerodynamic panel method is developed using a distributed set of doublet panels over the surface of the airfoil and along its wake. When the aerodynamic loads predicted by this panel method are made available to the Matrix Exponential time marching scheme for every time interval, a dynamic aeroelastic solver for a time varying aeroelastic system is obtained. This solver is now used to train an array of neural networks to represent the response of this two dimensional aeroelastic system with a time varying torsional stiffness. These neural networks are developed into a control system for flutter suppression. Another type of aeroelastic problem of an adaptive structure that is investigated here is the shape control of an adaptive bump situated on the leading edge of an airfoil. Such a bump is useful in achieving flow separation control for lateral directional maneuverability of the aircraft. Since actuators are being used to create this bump on the wing surface, the energy required to do so needs to be minimized. The adverse pressure drag as a result of this bump needs to be controlled so that the loss in lift over the wing is made minimal. The design of such a "spoiler bump" on the surface of the airfoil is an optimization problem of maximizing pressure drag due to flow separation while minimizing the loss in lift and energy required to deform the bump. One neural network is trained using the CFD code FLUENT to represent the aerodynamic loading over the bump. A second neural network is trained for calculating the actuator loads, bump displacement and lift, drag forces over the airfoil using the finite element solver, ANSYS and the previously trained neural network. This non-linear aeroelastic model of the deforming bump on an airfoil surface using neural networks can serve as a fore-runner for other non-linear aeroelastic problems. This work enhances the traditional aeroelastic modeling by introducing time varying parameters in the differential equations of motion. It investigates the calculation of non-conservative aerodynamic loads on morphing contours and the resulting structural deformation for non-linear aeroelastic problems through the use of neural networks. Geometric modeling of morphing contours is also addressed. / Ph. D.
66

Adoptable Space

Wenzel, Andreas 29 December 2004 (has links)
This project investigates an idea of adoptable space as opposed to adaptable space of generic flexibility. An Experimental Performing Arts Center on a site in Downtown Chattanooga is used as a vehicle to define the nature of space, which offers itself for an architectural adoption. Simple elements like platforms, walls, doors, windows and curtains are interpreted in a new way and can be used experimentally to let a theater play happen. / Master of Architecture
67

State estimation for coupled PDE systems using Modulation Functions

Pumaricra Rojas, David Raul 27 April 2022 (has links)
This master thesis is devoted to the state estimation of a particular form of PDE systems, coupled parabolic PDEs with spatial dependent coefficients. This form of PDEs represent some dynamic systems such as Tubular Reactors, Diffusion in lithium-ion cells and Diffusive Gradient in Thin Films sensor. Other methods for this problem use "Backstepping" observers, in which the estimation error system is transformed into another system that is stable, reducing the problem to calculate the Kernel functions making the transformation possible. In some cases this calculation is not simple, also the simulation in real time of the observer system, that is also a PDE, can be difficult. The method presented in this thesis uses the properties of the so-called Modulating Functions in order to estimate the states. The procedure con- sists of generating an orthonormal basis of functions that can represent the state as a combination of them. Then auxiliary systems are formed from the original systems with boundary conditions that help in the simplification of the problem. Resolving these auxiliary systems, result in the calculation of the Modulating kernels. All of these steps can be made offline and do not have to be repeated. The functions are used together with the orthonormal basis in the online part, that consists of an inte- gration of a combination of the kernel functions, inputs and outputs of the system in a time window. Finally, with a matrix multiplication the coefficients for the ba- sis expansion of the state can be obtained, resulting in the desired state estimation. The present method is tested in systems that resemble the forms of the dynamics of Tubular Reactors and the performance is compared to other methods. / Diese Masterarbeit widmet sich der Zustandsschätzung einer bestimmten Art von Systemen, gekoppelten partiellen Differenzialgleichungen mit raumabhängigen Ko- effizienten. Diese besondere Form von PDEs repräsentiert einige dynamische Sys- teme wie Röhrenreaktoren, Diffusion in Lithium-Ionen-Batterien und Gradienten in dünnen Schichten. Andere Methoden für dieses Problem benutzen "Backstep- ping" Beobachter, bei denen das Schätzfehlersystem in ein anderes stabiles System transformiert wird, wodurch das Problem reduziert wird, um die Kernfunktionen zu berechnen, die die Transformation ermöglichen. In manchen Fällen ist diese Berech- nung nicht einfach. Auch die Simulation in Echtzeit des Beobachters System, das auch eine PDE ist, kann sehr schwierig sein. Die in dieser Arbeit vorgestellte Meth- ode verwendet die Eigenschaften der sogenannten Modulationsfunktionen, um die Zustände zu schätzen. Das Verfahren besteht darin, eine Orthonormalbasis von Funktionen zu erzeugen können, die den Zustand als Kombination von ihnen repräsen- tieren, dann werden Hilfssysteme gebildet von dem ursprünglichen Systemen mit Randbedingungen, die bei der Vereinfachung helfen, von dem Problem. Das Au- flösen dieser Hilfssysteme ergibt die Berechnung der modulierende Kerne. Alle diese Schritte können offline durchgeführt und müssen nicht wiederholt werden. Die Funktionen werden zusammen mit der Orthonormalbasis im Online-Teil ver- wendet. Dieser Teil besteht aus einer Integration einer Kombination der Kernfunk- tionen, Eingaben und Ausgaben des Systems in einem Zeitfenster. Schließlich kön- nen die Koeffizienten zur Basiserweiterung mit einer Matrixmultiplikation berech- net werden, was zu der gewünschte Zustandsschätzung führt. Das Verfahren wird am Beispiel der Dynamik eines Rohreaktors getestet und die Ergebnisse werden mit anderen Methoden verglichen.
68

Plate-forme de composants logiciels pour la coordination des adaptations multiples en environnement dynamique

Chefrour, Djalel 22 November 2005 (has links) (PDF)
L'objectif de cette thèse est de contribuer au développement de méthodes et d'outils<br />pour l'adaptation de composants logiciels et pour leur coordination en environnement<br />dynamique.<br />Nous proposons une capture des mécanismes de l'adaptabilité dans un modèle de<br />composants générique basé sur la réflexivité et les techniques objet. Ces composants<br />reposent sur un service de surveillance de l'environnement et sur un intergiciel de coordination<br />des adaptations. La coordination inclut la gestion des dépendances entre les<br />composants interagissants et/ou concurrents.<br />En instaurant la séparation des préoccupations, notre approche facilite la tâche du<br />développeur à qui nous offrons des langages déclaratifs pour spécifier les politiques qui<br />contrôlent les adaptations des composants et leur coordination dans des scripts séparés.<br />Nous avons montré l'utilité de notre modèle, appelé Aceel, en l'utilisant pour développer<br />une application vidéo et un navigateurWeb adaptables en environnement mobile.
69

Design for adaptability

Hashemian, Mehdi 07 June 2005
Manufacturing globalization and sustainable development compel production enterprises to continuously seek improvements in their products performance, customization, environmental friendliness, cost, and delivery time. The challenges of this competition cannot be completely addressed through improving production processes because some issues can only be solved through more innovative design. This thesis investigates a new design paradigm called Design for Adaptability or Adaptable Design (AD) to address some of these challenges. The purpose of AD is to extend the utility of designs and products. An adaptable design allows manufacturers to quickly develop new and upgraded models or customized products through adapting existing designs with proven quality and costs. An adaptable product can be utilized under varying service requirements thus prevents premature product replacement. Design adaptability and product adaptability provide economical and environmental benefits of AD. <p> To make a product adaptable, its adaptability must be built-in during the design stage. Methods of design for predetermined adaptations are categorized as Specific AD; these methods design products for versatility, upgrading, variety, and customization. Several of these methods such as modular/platform design and design for upgrading have been studied for mechanical design. In the absence of predetermined adaptations, AD aims to increase the general adaptability of products. General AD involves fundamental research in design theory and methodology in order to develop practical design methods and guidelines. This thesis introduces several original concepts and proposes the subordination of a system to a rational functional structure as an approach for increasing general adaptability. Such a system would consist of a hierarchical assembly of autonomous functional modules, emulating the adaptable architecture of a rational functional structure. Methods and guidelines are proposed for making the design of mechanical systems closer to this ideal architecture. <p> Accordingly, the thesis proposes a methodology for AD in which specific AD is performed first to take advantage of available forecast information, and then general AD is performed in order to increase adaptability to unforeseen changes. Also, a measure has been defined for the assessment of adaptability. The application of this methodology has been demonstrated through several conceptual design examples.
70

Design for adaptability

Hashemian, Mehdi 07 June 2005 (has links)
Manufacturing globalization and sustainable development compel production enterprises to continuously seek improvements in their products performance, customization, environmental friendliness, cost, and delivery time. The challenges of this competition cannot be completely addressed through improving production processes because some issues can only be solved through more innovative design. This thesis investigates a new design paradigm called Design for Adaptability or Adaptable Design (AD) to address some of these challenges. The purpose of AD is to extend the utility of designs and products. An adaptable design allows manufacturers to quickly develop new and upgraded models or customized products through adapting existing designs with proven quality and costs. An adaptable product can be utilized under varying service requirements thus prevents premature product replacement. Design adaptability and product adaptability provide economical and environmental benefits of AD. <p> To make a product adaptable, its adaptability must be built-in during the design stage. Methods of design for predetermined adaptations are categorized as Specific AD; these methods design products for versatility, upgrading, variety, and customization. Several of these methods such as modular/platform design and design for upgrading have been studied for mechanical design. In the absence of predetermined adaptations, AD aims to increase the general adaptability of products. General AD involves fundamental research in design theory and methodology in order to develop practical design methods and guidelines. This thesis introduces several original concepts and proposes the subordination of a system to a rational functional structure as an approach for increasing general adaptability. Such a system would consist of a hierarchical assembly of autonomous functional modules, emulating the adaptable architecture of a rational functional structure. Methods and guidelines are proposed for making the design of mechanical systems closer to this ideal architecture. <p> Accordingly, the thesis proposes a methodology for AD in which specific AD is performed first to take advantage of available forecast information, and then general AD is performed in order to increase adaptability to unforeseen changes. Also, a measure has been defined for the assessment of adaptability. The application of this methodology has been demonstrated through several conceptual design examples.

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