| 1. |
- Nordin, Peter
(författare)
-
Mobile Robot Traversability Mapping : For Outdoor Navigation
- 2012
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- To avoid getting stuck or causing damage to a vehicle or its surroundings a driver must be able to identify obstacles and adapt speed to ground conditions. An automatically controlled vehicle must be able to handle these identifications and adjustments by itself using sensors, actuators and control software. By storing properties of the surroundings in a map, a vehicle revisiting an area can benefit from prior information.Rough ground may cause oscillations in the vehicle chassis. These can be measured by on-board motion sensors. For obstacle detection, a representation of the geometry of the surroundings can be created using range sensors. Information on where it is suitable to drive, called traversability, can be generated based on these kinds of sensor measurements.In this work, real semi-autonomous mobile robots have been used to create traverasbility maps in both simulated and real outdoor environments. Seeking out problems through experiments and implementing algorithms in an attempt to solve them has been the core of the work.Finding large obstacles in the vicinity of a vehicle is seldom a problem; accurately identifying small near-ground obstacles is much more difficult, however. The work additionally includes both high-level path planning, where no obstacle details are considered, and more detailed planning for finding an obstacle free path. How prior maps can be matched and merged in preparation for path planning operations is also shown. To prevent collisions with unforeseen objects, up-to-date traversability information is used in local-area navigation and obstacle avoidance.
|
|
| 2. |
- Olofsson, Jonas, 1978-
(författare)
-
Gender differences in chemosensory function
- 2005
-
Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of two studies, in which gender differences in nasal chemosensory function are investigated. The first study assesses odor identification ability in a populationbased sample, varying from 45 to 90 yrs, screened for cognitive impairment and severe olfactory dysfunction. Results show that women are generally better than men at identifying odors, but there is no significant interaction of gender by age. Although odoridentification is influenced by semantic memory and cognitive speed, these cognitivefactors are unlikely to cause the observed gender difference in odor identification. The second study investigates chemosensory perception in men and women by assessing eventrelatedbrain potentials, and perceptual ratings for an odorant, which varies inconcentration and olfactory/irritating properties. The results display a generally larger cortical response in women than in men, beginning from about 350 ms after stimulus onset. Women report higher perceived intensity and npleasantness at the highest stimulus concentration, and a steeper psychophysical function, than do men. The results indicatethat stronger cortical responses of nasal chemosensory stimuli provide a neural basis for stronger supra-threshold perception in women than in men, which might enhance odor identification performance. The nature and causes of these gender-differences in nasal chemosensory function are discussed. This thesis for the licenciate degree is based on the following studies:Larsson, M., Nilsson, L-G., Olofsson, J.K., & Nordin, S. (2004). Demographic and cognitive predictors of odor identification: Evidence from a population-based study.Chemical Senses, 29, 547-554.Olofsson, J.K., & Nordin, S. (2004). Gender differences in chemosensory perception andevent-related potentials. Chemical Senses, 29, 629-637.
|
|
