Thesis (M.S.)--University of Wisconsin--Madison, 1996. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 69).

Thesis (Ph. D.)--York University, 2000. Graduate Programme in Sociology. / Typescript. Includes bibliographical references (leaves 605-654). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNQ56230.

Municipal water conservation programs often highlight water-wise landscaping as a method to reduce household water consumption. To determine if any relationships between landscaping and home water consumption exist in Strathcona County, Alberta, water consumption data for two neighbourhoods was collected. GIS mapping was used to compare these results with percentages of lawn and yard areas. Indoor and outdoor water use practices were explored through a door-to-door survey. Lawn size was found to have an impact on outdoor water consumption, per metre squared, with small lawns being the largest water users per area. No matter what vegetation is planted on the landscape, the size of yard also resulted in summer water use increases. Outside of programs to reduce lawn area, Strathcona County and other cold-climate communities could also look at behaviours such as frequency of watering and use of rain barrels to reduce summer water use.

This master thesis contains modeling and nonlinear automatic control of an autonomous lawn mower. The vehicle shall be able to follow a magnetic field loop buried in the lawn on an arbitrary distance, including straddling. A unicycle model of the lawn mower has been derived based on previous work. The model holds for the assumption of non slip environment. Two diff erent control strategies have been implemented and evaluated in this thesis. One is based on feedback linearization  and with the feedback gain estimated using an LQ-controller. The other strategy is based on linearization at an equilibrium point  and also with the use of an LQ-controller. The only state that can be measured is the distance to the magnetic loop. In order to estimate the other states, an observer has been implemented using the linearized in an equilibrium point  model and a Kalman filter. The navigation of the autonomous lawn mower is performed using a magnetic loop buried in the lawn. The non-linearity of the magnetic field causes diffi culties when estimating the distance to the loop. One magnetic field strength corresponds to two distances to the magnetic loop. The nature of the magnetic field and the measurement noise causes the precision of the controller to be limited. The conclusion of this master thesis is that it is possible to navigate and follow the magnetic loop at a distance greater than 0.3 [m], but with overshoots during sharp turns. If the reference distance is smaller than that, the behavior of the robot will be oscillating when following the loop. The limitations of the controller performance is due to the lack of information which can be extracted from the measurements of the magnetic field.

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