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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.
481

Transparency and Movement in Architecture

Estremadoyro, Veronica 27 August 2008 (has links)
This project investigates transparency and movement as the main measured elements that define space. These elements seek to articulate distinct and memorable places throughout the building, acknowledging its unique setting along the Potomac River in Old Town Alexandria, Virginia. Architecture and nature as opposite elements combine here to define a building in which water, light and views become the main architectural agents set in dialog with the natural surroundings. An existing boardwalk along the levee transforms into a transparent enclosed space that connects both city and water on opposite sides. Programmatically a series platforms, walls and volumes are inhabited by a cultural center. The cultural center contributes to the artistic spirit and identity of the city by concentrating various artistic representations. / Master of Architecture
482

A new guidance trajectory generation algorithm for unmanned systems incorporating vehicle dynamics and constraints

Balasubramanian, Balasundar 27 January 2011 (has links)
We present a new trajectory generation algorithm for autonomous guidance and control of unmanned vehicles from a given starting point to a given target location. We build and update incomplete a priori maps of the operating environment in real time using onboard sensors and compute level sets on the map reflecting the minimal cost of traversal from the current vehicle location to the goal. We convert the trajectory generation problem into a finite-time-horizon optimal control problem using the computed level sets as terminal costs in a receding horizon framework and transform it into a simpler nonlinear programming problem by discretization of the candidate control and state histories. We ensure feasibility of the generated trajectories by constraining the solution of the optimization problem using a simplified vehicle model. We provide strong performance guarantees by checking for stability of the algorithm through the test of matching conditions at the end of each iteration. The algorithm thus explicitly incorporates the vehicle dynamics and constraints and generates trajectories realizable by the vehicle in the field. Successful preliminary field demonstrations and complete simulation results for a marine unmanned surface vehicle demonstrate the efficacy of the proposed approach for fast operations in poorly characterized riverine environments. / Master of Science
483

Optimal Vehicle Path Generator Using Optimization Methods

Ramanata, Peeroon Pete 24 April 1998 (has links)
This research explores the idea of developing an optimal path generator that can be used in conjunction with a feedback steering controller to automate track testing experiment. This study specifically concentrates on applying optimization concepts to generate paths that meet two separate objective functions; minimum time and maximum tire forces. A three-degree-of freedom vehicle model is used to approximate the handling dynamics of the vehicle. Inputs into the vehicle model are steering angle and longitudinal force at the tire. These two variables approximate two requirements that are essential in operating a vehicle. The Third order Runge-Kutta integration routine is used to integrate vehicle dynamics equations of motion. The Optimization Toolbox of Matlab is used to evaluate the optimization algorithm. The vehicle is constrained with a series of conditions, includes, a travel within the boundaries of the track, traction force limitations at the tire, vehicle speed, and steering. The simulation results show that the optimization applied to vehicle dynamics can be useful in designing an automated track testing system. The optimal path generator can be used to develop meaningful test paths on existing test tracks. This study can be used to generate an accelerated tire wear test path, perform parametric study of suspension geometry design using vehicle dynamics handling test data, and to increase repeatability in generating track testing results. <i> Vita removed at author's request. GMc 3/13/2013</i> / Master of Science
484

In Search of Equilibrium: Containers of Light

Kamat, Smruti 21 September 2005 (has links)
The goal of this thesis is to find that point of equilibrium in a composition where nothing can be added and nothing can be taken away. Each and every element is vital and any addition or subtraction will disturb this equilibrium. The nature of this investigation requires a program where simplicity is a virtue. The word temple is derived from 'temnere', which means to cut, to take away. I understand this as a process of subtracting to create meaning out of something that would otherwise have been inert matter. The program proposes a sequence of three distinct spaces for contemplation, and welcomes people of any faith. While it is impossible to meet the exact requirements of each religion, there is a common thread that ties all sacred spaces together. The goal of this project is to create a silent meditative environment by bringing into play essential qualities of the space itself such as material and light. / Master of Architecture
485

4 walls +

Ebert, Doreen 06 June 2000 (has links)
A higher level of complexity is possible by combining more than one idea as long as the order of the elements is readable in each built condition. Order is possible at any level of complexity. The more complex the greater the need of order. Order can be the relationship of a limited set of elements that inform and reform each other. / Master of Architecture
486

An Investigation of the Clothoid Steering Model for Autonomous Vehicles

Meidenbauer, Kennneth Richard 20 August 2007 (has links)
The clothoid, also known as the Cornu spiral, is a curve generated by linearly increasing or decreasing curvature as a function of arc length. The clothoid has been widely accepted as a logical curve for transitioning from straight segments to circle arcs in roads and railways, because a vehicle following the curve at constant speed will have a constant change of centripetal acceleration. Clothoids have also been widely adopted in planning potential paths for autonomous vehicle navigation. They have been viewed as useful representations of possible trajectories that are dynamically feasible. Surprisingly, the assumptions that underlie this choice appear to be lightly treated or ignored in past literature. This thesis will examine three key assumptions that are implicitly made when assuming that a vehicle will follow a clothoid path. The first assumption is that the vehicle's steering mechanism will produce a linear change in turning radius for a constant rate input. This assumption is loosely referred to as the "bicycle model" and it relates directly to the kinematic parameters of the steering mechanism. The second assumption is that the steering actuator can provide a constant steering velocity. In other words, the actuator controlling the steering motion can instantaneously change from one rate to another. The third assumption is that the vehicle is traveling at a constant velocity. By definition, the clothoid is a perfect representation of a vehicle traveling at constant velocity with a constant rate of change in steering curvature. The goal of this research was to examine the accuracy of these assumptions for a typical Ackermann-steered ground vehicle. Both theoretical and experimental results are presented. The vehicle that was used as an example in this study was a modified Club Car Pioneer XRT 1500. This Ackermann-steered vehicle was modified for autonomous navigation and was one of Virginia Tech's entries in the DARPA 2005 Grand Challenge. As in typical operation, path planning was conducted using the classic clothoid curve model. The vehicle was then commanded to drive a selected path, but with variations in speed and steering rate that are inherent to the real system. The validity of the three assumptions discussed above were examined by comparing the actual vehicle response to the planned clothoid. This study determined that the actual paths driven by the vehicle were generally a close match to the originally planned theoretical clothoid path. In this study, the actual kinematics of the Ackermann vehicle steering system had only a small effect on the driven path. This indicates that the bicycle model is a reasonable simplification, at least for the case studied. The assumption of constant velocity actuation of the steering system also proved to be reasonably accurate. The greatest deviation from the planned clothoid path resulted from the nonlinear velocity of the vehicle along the path, especially when accelerating from a stop. Nevertheless, the clothoid path plan generally seems to be a good representation of actual vehicle motion, especially when the planned path is updated frequently. / Master of Science
487

Urban Renewal

Johnson, Sarah Marie 09 December 2010 (has links)
This thesis is an exploration of how an existing parking lot in Washington, DC is transformed into a greenspace with ten public pavilions. This structured garden is designed to promote solitude and reflection and to develop an awareness of path, movement, composition, scale, and material. / Master of Architecture
488

Uncertainty-aware path planning on aerial imagery and unknown environments

Moore, Charles Alan 10 May 2024 (has links) (PDF)
Off-road autonomous navigation faces a significant challenge due to the lack of maps or road markings for planning paths. Classical path planning methods assume a perfectly known envi- ronment, neglecting the inherent perception and sensing uncertainty from detecting terrain and obstacles in off-road environments. This research proposes an uncertainty-aware path planning method, URA*, using aerial images for autonomous navigation in off-road environments. An ensemble convolutional neural network model is used to perform pixel-level traversability estima- tion from aerial images of the region of interest. Traversability predictions are represented as a grid of traversal probability values. An uncertainty-aware planner is applied to compute the best path from a start point to a goal point, considering these noisy traversal probability estimates. The proposed planner also incorporates replanning techniques for rapid replacement during online robot operation. The method is evaluated on the Massachusetts Road Dataset, DeepGlobe dataset, and aerial images from CAVS proving grounds at MSU.
489

Mativation : En kvantitativ studie om elevers värdering av lärares motivationsskapande ledarskap / Mathivation : A quantitative study on students' evaluation of teachers' motivational leadership

Elheim, Wille, Iversen, Edvin January 2024 (has links)
Denna kvantitativa studie fokuserar på att bidra med kunskap om hur pojkar och flickor i årskurs 6 värderar olika ledarskapsbeteende utifrån Path-goal theory. Värderingen av de olika ledarskapsbeteenden skedde med avseende för att skapa motivation i ämnet matematik. Studien har samlat in svar från 110 elever i årskurs 6 på ett frågeformulär med utgångspunkt i Northouse (2018) enkät relaterade till Path-goal theory. Vid analysen för arbetet genomfördes en deskriptiv analys samt ett Chi2-test. Vårt resultat har visat att elever i årskurs 6 värderar ett vägledande ledarskap högst, följt av prestationsorienterade, sen stödjande och till sist deltagande. Chi2-testet visar även på en statistisk signifikant skillnad i värdering av de olika ledarskapsbeteenden mellan flickor och pojkar. Nollhypotesen, om att pojkar och flickor värderar ledarskapsbeteendena lika, kunde vid testet förkastas.
490

Cooperative human-robot search in a partially-known environment using multiple UAVs

Chourey, Shivam 28 August 2020 (has links)
This thesis details out a system developed with objective of conducting cooperative search operation in a partially-known environment, with a human operator, and two Unmanned Aerial Vehicles (UAVs) with nadir, and front on-board cameras. The system uses two phases of flight operations, where the first phase is aimed at gathering latest overhead images of the environment using a UAV’s nadir camera. These images are used to generate and update representations of the environment including 3D reconstruction, mosaic image, occupancy image, and a network graph. During the second phase of flight operations, a human operator marks multiple areas of interest for closer inspection on the mosaic generated in previous step, displayed via a UI. These areas are used by the path planner as visitation goals. The two-step path planner, which uses network graph, utilizes the weighted-A* planning, and Travelling Salesman Problem’s solution to compute an optimal visitation plan. This visitation plan is then converted into Mission waypoints for a second UAV, and are communicated through a navigation module over a MavLink connection. A UAV flying at low altitude, executes the mission plan, and streams a live video from its front-facing camera to a ground station over a wireless network. The human operator views the video on the ground station, and uses it to locate the target object, culminating the mission. / Master of Science / This thesis details out the work focused on developing a system capable of conducting search operation in an environment where prior information has been rendered outdated, while allowing human operator, and multiple robots to cooperate for the search. The system operation is divided into two phases of flight operations, where the first operation focuses on gathering the current information using a camera equipped unmanned aircraft, while the second phase involves utilizing the human operator’s instinct to select areas of interest for a close inspection. It is followed by a flight operation using a second unmanned aircraft aimed at visiting the selected areas and gathering detailed information. The system utilizes the data acquired through first phase, and generates a detailed map of the target environment. In the second phase of flight operations, a human uses the detailed map, and marks the areas of interest by drawing over the map. This allows the human operator to guide the search operation. The path planner generates an optimal plan of visitation which is executed by the second unmanned aircraft. The aircraft streams a live video to a ground station over a wireless network, which is used by the human operator for detecting the target object’s location, concluding the search operation.

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