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11	Vision-Based Obstacle Avoidance for Multiple Vehicles Performing Time-Critical Missions Dippold, Amanda 11 June 2009 (has links) This dissertation discusses vision-based static obstacle avoidance for a fleet of nonholonomic robots tasked to arrive at a final destination simultaneously. Path generation for each vehicle is computed using a single polynomial function that incorporates the vehicle constraints on velocity and acceleration and satisfies boundary conditions by construction. Furthermore, the arrival criterion and a preliminary obstacle avoidance scheme is incorporated into the path generation. Each robot is equipped with an inertial measurement unit that provides measurements of the vehicle's position and velocity, and a monocular camera that detects obstacles. The obstacle avoidance algorithm deforms the vehicle's original path around at most one obstacle per vehicle in a direction that minimizes an obstacle avoidance potential function. Deconfliction of the vehicles during obstacle avoidance is achieved by imposing a separation condition at the path generation level. Two estimation schemes are applied to estimate the unknown obstacle parameters. The first is an existing method known in the literature as Identifier-Based Observer and the second is a recently-developed fast estimator. It is shown that the performance of the fast estimator and its effect on the obstacle avoidance algorithm can be arbitrarily improved by the appropriate choice of parameters as compared to the Identifier-Based Observer method. Coordination in time of all vehicles is completed in an outer loop which adjusts the desired velocity profile of each vehicle in order to meet the simultaneous arrival constraints. Simulation results illustrate the theoretical findings. / Ph. D. Path generation path following obstacle avoidance path deformation vision-based estimation visual sensors coordinated control time-critical missions
12	Procedural Worlds : A proposition for a tool to assist in creation of landscapes byprocedural means in Unreal Engine 5 Sjögren, Viktor, Malteskog, William January 2023 (has links) This thesis explores the possibilities of creating landscapes through procedural means within the game engine Unreal Engine 5. The aim is to provide a flexible procedural landscape tool that doesn't limit the user and that is compatible with existing systems in the engine. The research questions focuses on comparison to other work regarding landscape generation and generation of procedural roads. The process to achieve this was done through extensive implementation adding modules that both builds upon and adds to the source code. The implementation was divided into five major components, which was noise generation for terrain, biotope interpolation, asset distribution, road generation and a user interface. Perlin noise, utilizing Fractal Brownian Motion were a vital part of generating terrain with varying features. For interpolation a modified version of Lowpass Gaussian filtering was implemented in order to blend biotope edges together. Asset distribution and road generation were implemented in a way that uses pseudo-randomness combined with heuristics. The user interface was done to tie everything together for testing. The results shows potential for assisting in procedural landscape creation with a large amount of freedom in customization. There is however flaws in some aspects, namely the interpolation methods suffer from clear visual artefacts. Whether it is suitable for professional standards remains to be fully proven objectively as the testing in this thesis work was limited. Procedural Generation PCG Terrain generation Unreal Engine Path generation Catmull-Rom splines Noise Perlin noise Biomes Interpolation Computer Sciences Datavetenskap (datalogi)
13	Optimal Synthesis of Adjustable Four-Link Planar and Spherical Crank-Rocker Type Mechanisms for Approximate Multi-Path Generation Vilas, Chanekar Prasad January 2013 (has links) (PDF) The well known synthesis problem of obtaining dimensions of a four-link mechanism such that a point on the coupler link traces a desired path has been extensively studied. There are two types of path generation–path specified by a finite number of precision points where the prescribed points must be exactly traced, and continuous path generation where the path is approximately traced by the coupler point. In various application, more than one or multiple paths are required to be traced by the coupler point and in such cases, adjustable four-link mechanisms where one of the dimension or parameters of the mechanism can be changed is a possible solution. This thesis deals with the synthesis of planar and spherical adjustable four-link crank-rocker type mechanisms for multiple continuous path generation. Approximate multiple path generation is typically solved as an optimization problem where the dimensions and parameters of the four-link mechanism are obtained such that the objective functions, typically in terms of an error between the desired and obtained path, is minimized. In this thesis, we present a two-stage optimization to obtain four-link mechanism dimensions such that the adjustable four-link mechanism can approximately trace multiple desired paths. In the first stage, the parameters in the driving side of the four-link mechanism is obtained and in the second stage, the parameters of the driven side are obtained. In case of adjustable planar four-link mechanism, a novel optimization objective function based on circle-fitting is used and for spherical adjustable mechanisms a novel plane-fitting based objective function is used. The use of these objective functions results in a lesser number of variables to be searched and thus the method presented in this work is more efficient than existing optimization based algorithms available in literature. Several examples are presented for synthesis of adjustable planar and spherical four-link mechanism for tracing multiple paths. In particular, a spherical mechanism which can generate an oval and an‘ 8’shaped path by one single adjustment is synthesized. This mechanism has been made using 3D printing and it is shown that the mechanism indeed traces the desired oval and ‘8’ shaped paths. This mechanism is being planned for use in a flapping wing micro air vehicle where the oval shaped path is known to make the vehicle to move forward while the ‘8’ shaped path results in a hovering motion. Adjustable Planar Four-Bar Mechanisms Multiple Path Genertion Kinematics Four-Link Mechanisms - Kinematics Mechanisms (Engineering) Four-Link Mechanisms - Path Generation Planar Four-Bar Mechanism Spherical Four-Link Mechanism Path Generation Mechanical Engineering
14	技能者による生産計画に対する工夫を支援する高機能CNC装置の開発樋野, 励, 清水, 良明, 柳, 在圭 05 1900 (has links) 科学研究費補助金研究種目:基盤研究(C) 課題番号:16560225 研究代表者:樋野励研究期間:2004-2005年度 CNC device CNC装置 Decentralized scheduling Recursive propagation method Schedule Skilled worker Tool path generation スケジュール分散スケジューリング分散スケジュール工具経路補正技能者
15	GIS-based Episode Reconstruction Using GPS Data for Activity Analysis and Route Choice Modeling / GIS-based Episode Reconstruction Using GPS Data Dalumpines, Ron 26 September 2014 (has links) Most transportation problems arise from individual travel decisions. In response, transportation researchers had been studying individual travel behavior – a growing trend that requires activity data at individual level. Global positioning systems (GPS) and geographical information systems (GIS) have been used to capture and process individual activity data, from determining activity locations to mapping routes to these locations. Potential applications of GPS data seem limitless but our tools and methods to make these data usable lags behind. In response to this need, this dissertation presents a GIS-based toolkit to automatically extract activity episodes from GPS data and derive information related to these episodes from additional data (e.g., road network, land use). The major emphasis of this dissertation is the development of a toolkit for extracting information associated with movements of individuals from GPS data. To be effective, the toolkit has been developed around three design principles: transferability, modularity, and scalability. Two substantive chapters focus on selected components of the toolkit (map-matching, mode detection); another for the entire toolkit. Final substantive chapter demonstrates the toolkit’s potential by comparing route choice models of work and shop trips using inputs generated by the toolkit. There are several tools and methods that capitalize on GPS data, developed within different problem domains. This dissertation contributes to that repository of tools and methods by presenting a suite of tools that can extract all possible information that can be derived from GPS data. Unlike existing tools cited in the transportation literature, the toolkit has been designed to be complete (covers preprocessing up to extracting route attributes), and can work with GPS data alone or in combination with additional data. Moreover, this dissertation contributes to our understanding of route choice decisions for work and shop trips by looking into the combined effects of route attributes and individual characteristics. / Dissertation / Doctor of Philosophy (PhD) GPS time use diary episode extraction multinomial logit travel behavior mode detection episode reconstruction GIS map-matching route choice path size logit potential path area scale estimation Python ArcGIS activity analysis trip reconstruction smartphone global positioning system geographic information system toolkit work trip shop trip potential activity location land use activity episode travel episode stop episode transferability scalability modularity scripting big data travel survey respondent burden preprocessing multipath error tracking purpose detection segmentation data filter data smoothing fuzzy logic neural network decision tree rule-based algorithm trajectory point road network network dataset gateway shortest path horizontal dilution of precision HDOP commonality factor mode transfer point Halifax Nova Scotia Space-Time Activity Research variance inflation factor shapefile comma-separated values traveling salesman problem data mining branch-and-bound algorithm pedestrian network alternative route observed route route efficiency route attributes distance time heading bearing duration acceleration latitude longitude coordinate overlay analysis intersect shopping module data logger walk likelihood ratio test classification table path generation kappa statistic degrees data collection transportation research automate framework ArcToolbox spatio-temporal navigation positioning trace path spatial data topology horizontal accuracy SPSS Stata spatial resolution temporal resolution household survey trip reporting proximity analysis DMTI Desktop Mapping Technologies Inc. road intersection route overlap left turn right turn location analysis time geography spatial statistics buffer analysis cycling bus transit public transportation GEOIDE AGILE data need raw data urban canyon endpoint data cleaning elevation satellite outliers automatic processing nearest node classifier classification method short trip multi-point

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