This thesis looks at the problem of optimally placing binary directional proximity markers to assist a robot as it navigates waypoints through an environment. A simple planar fiducial marker is developed to serve as the binary directional proximity marker. A scoring function is proposed for marker placement as well as a method for random generation of hallway maps. Several common metaheuristic algorithms are run to find optimal marker placements with respect to the scoring function for a number of randomly generated hallway maps. From these results, placements are then evaluated by physical experimentation on an iRobot Create equipped with relatively inexpensive webcams. / Graduate

The pedunculopontine tegmental nucleus (PPTg) lies within the pontomesencephalon and contains cholinergic and non-cholinergic neurones. It has extensive afferent and efferent connections throughout the brain. Early research suggested a role for the PPTg in the mediation of locomotor activity, and it was believed to form the major substrate of the electrophysiologically identified mesencephalic locomotor region (rviLR). Studies using selective excitotoxic lesions of the PPTg demonstrated that it has no role in the mediation of spontaneous or nucleus accumbens-induced (NAcc) locomotion. However evidence has suggested that the cuneiform nucleus (CNF) and not the PPTg is the main locus of the .MLR. The effects of bilateral ibotenate CNF lesions on spontaneous and amphetamine-induced locomotion stimulated from the NAcc were therefore investigated. CNF lesions had no effect on either type of locomotor activity. Bilateral ibotenate lesions of the PPTg have been shown to influence the expression of orofacial stereotypies following administration of systemic amphetamine. Oral stereotypies can be elicited reliably by direct stimulation of the ventrolateral caudate-putamen (VLCP). This thesis sought to clarify the role of the PPTg in the mediation of oral stereotypies, by combining bilateral ibotenate lesions of the PPTg with direct microinjection of amphetamine into the VLCP. Lesions of the PPTg caused a shift in the dose response curve to amphetamine resulting in an increase in the incidence and intensity of oro facial stereotypies at lower doses. Thus the PPTg appears to have inhibitory control over the expression of orofacial behaviors. It is hypothesised that while neither the PPTg nor the CNF have a role in the mediation of locomotor activity per se they may provide an integrative functional role, which influences motor outflow. The role of the CNF in the transmission of nociception and a role for the PPTg in the mediation of striatal outflow is discussed.

No description available.

Current planetary rover localization techniques are lacking in autonomy and accuracy. An autonomous method of globally localizing a rover is proposed by matching features extractedvfrom a 3D orbital elevation map and rover-based 3D lidar scans. Localization can be further improved by including odometry measurements as well as orientation measurements from an inclinometer and sun sensor. The methodology was tested with real data from a Mars-Moon analogue site on Devon Island, Nunavut. By tying 23 real scans together with simulated odometry over a 10km traverse, the algorithm was able to localize with varying degrees of accuracy. Output uncertainties were large due to large input uncertainties, but these could be reduced in future experimentation by minimizing the use of simulated input data. It was concluded that the architecture could be used to accurately and autonomously localize a rover over long-range traverses.

An ultra-wideband (UWB) spatial filter is proposed to mitigate multipath effects in a one-way, one-dimensional time-of-arrival (TOA) localization system for use inside a tunnel. The spatial filter is a weighted array of judiciously placed antennas and it exploits the fact that electromagnetic waves propagate as modes in a tunnel by selectively extracting these mode(s). The design of several spatial filters is presented alongside vigorous analyses to characterize the localization performance afforded by them in a noisy environment. The filters are evaluated using data from an analytical equation waveguide model, a ray tracer model and measurements. These spatial filters deliver accurate localization estimates across distance and well-designed filters can operate at higher SNRs and further distances than single sensors. Insights into successful spatial filter design are provided and this spatial filtering technique has created a new branch of multipath-aware localization systems.

Current planetary rover localization techniques are lacking in autonomy and accuracy. An autonomous method of globally localizing a rover is proposed by matching features extractedvfrom a 3D orbital elevation map and rover-based 3D lidar scans. Localization can be further improved by including odometry measurements as well as orientation measurements from an inclinometer and sun sensor. The methodology was tested with real data from a Mars-Moon analogue site on Devon Island, Nunavut. By tying 23 real scans together with simulated odometry over a 10km traverse, the algorithm was able to localize with varying degrees of accuracy. Output uncertainties were large due to large input uncertainties, but these could be reduced in future experimentation by minimizing the use of simulated input data. It was concluded that the architecture could be used to accurately and autonomously localize a rover over long-range traverses.

This dissertation consists of four different topics in the areas of proteomics, genomics, and cardiology. First, a data-based method was developed to assign the subcellular localization of proteins. We applied the method to data on the bacteria Rhodobacter sphaeroides 2.4.1 and compared the results to PSORTb v.3.0. We found that the method compares well to PSORTb and a simulation study revealed that the method is sound and produces accurate results. Next, we investigated genomic features involved in the lethality of the knockout mouse using the random forest technique. We achieved an accuracy rate of 0.725 and found that among other features, the evolutionary age of the gene was a good predictor of lethality. Third, we analyzed DNA breakpoints across eight different cancer types to determine if common hotspots or cancer-type specific hotspots can be well-predicted by various genomic features and investigated which of the genomic features best predict the number of breakpoints. Using the random forest technique, we found that cancer- type specific hotspots are poorly predicted by genomic features but common hotspots can be predicted using the relevant genomic features. Additionally, we found that among the genomic features analyzed, indel rate and substitution rate were consistently chosen as the top predictors of breakpoint frequency. Lastly, we developed a method to predict the hypothetical heart age of a subject based on the subject’s electrocardiogram (ECG). The heart age predictions are consistent with current ECG science and knowledge of cardiac health.

In this thesis, we study certain aspects of signal source/target localization by sensory agents and their biomedical applications. We first focus on a generic distance measurement based problem: Estimation of the location of a signal source by a sensory agent equiped with a distance measurement unit or a team of such a sensory agent. This problem was addressed in some recent studies using a gradient based adaptive algorithm. In this study, we design a least-squares based adaptive algorithm with forgetting factor for the same task. Besides its mathematical background, we perform some simulations for both stationary and drifting target cases. The least-squares based algorithm we propose bears the same asymptotic stability and convergence properties as the gradient algorithm previously studied. It is further demonstrated via simulation studies that the proposed least-squares algorithm converges significantly faster to the resultant location estimates than the gradient algorithm for high values of the forgetting factor, and significantly reduces the noise effects for small values of the forgetting factor. We also focus on the problem of localizing a medical device/implant in human body by a mobile sensor unit (MSU) using distance measurements. As the particular distance measurement method, time of flight (TOF) based approach involving ultra wide-band signals is used, noting the important effects of the medium characteristics on this measurement method. Since human body consists of different organs and tissues, each with a different signal permittivity coefficient and hence a different signal propagation speed, one cannot assume a constant signal propagation speed environment for the aforementioned medical localization problem. Furthermore, the propagation speed is unknown. Considering all the above factors and utilizing a TOF based distance measurement mechanism, we use the proposed adaptive least-square algorithm to estimate the 3-D location of a medical device/implant in the human body. In the design of the adaptive algorithm, we first derive a linear parametric model with the unknown 3-D coordinates of the device/implant and the current signal propagation speed of the medium as its parameters. Then, based on this parametric model, we design the proposed adaptive algorithm, which uses the measured 3-D position of the MSU and the measured TOF as regressor signals. After providing a formal analysis of convergence properties of the proposed localization algorithm, we implement numerical tests to analyze the properties of the localization algorithm, considering two types of scenarios: (1) A priori information regarding the region, e.g quadrant (among upper-left, upper-right, lower-left, lower-right of the human body), of the implant location is available and (2) such a priori information is not available. In (1), assuming knowledge of fixed average relative permittivity for each region, we established that the proposed algorithm converges to an estimate with zero estimation error. Moreover, different white Gaussian noises are added to emulate the TOF measurement disturbances, and it is observed that the proposed algorithm is robust to such noises/disturbances. In (2), although perfect estimation is not achieved, the estimation error is at a low admissible level. In addition, for both cases (1) and (2), forgetting factor effects have been investigated and results show that use of small forgetting factor values reduces noise effects significantly, while use of high forgetting factor values speeds up convergence of the estimation.

The objective of this investigation was to determine whether lesions to the region of the mammillary bodies of rats impair performance on various learning and memory tasks. It was demonstrated that such lesions are sufficient to impair performance on tasks that require memory for spatial information. Deficits were found in both working and reference memory paradigms, with more severe impairments in the former. Ability to discriminate spatial location was not affected when delay was minimal, but retention was progressively impaired as delay was increased. A dissociation in the effect of the lesions on performance of analogous spatial and nonspatial tasks was observed. The lesions did not impair the learning of a visual discrimination/reversal, or a conditioned taste aversion. It is concluded that lesions to the region of the mammillary bodies have a selective effect on spatial learning and memory. The relevance of these findings to Korsakoff's psychosis is discussed.

This doctoral work consists of several studies that investigated the relationship between language lateralization and structural asymmetries found in auditory and language-related regions of the human brain. Language lateralization was determined via the intracarotid Sodium Amytal procedure in epilepsy patients. In study 1, three groups of patients were investigated: a left speech group (LSG); a right speech group (RSG); and a bilateral speech group (BSG). Two auditory cortex regions: Heschl's gyrus (HG) and the planum temporale (PT) were labelled on the magnetic resonance imaging scan of each subject. Additionally, an automatic voxel-based morphometry (VBM) analysis was performed. The overall findings suggested that the structural asymmetries found in the auditory regions did not clearly and directly relate to language lateralization. The VBM analysis, however, revealed a grey matter concentration difference in the region of Broca's area favoring the left hemisphere (LH) in the LSG, and the right hemisphere (RH) in the RSG. That structural difference did relate to language lateralization and was further investigated in studies 2 and 3. Previously collected positron emission tomography data were examined in these two studies. Three regions of interest (ROI) analyses and one group average analysis were performed. Activation related to various speech tasks was examined. The ROI analyses revealed a significant activation difference favoring the LH for two targeted speech-task subtractions but only for the LSG. The group analysis, in contrast, revealed that the LSG showed a functional asymmetry favoring the LH, and that the RSG showed a functional asymmetry favoring the RH. Overall, the present results provided only partial evidence for a relationship existing between structural asymmetry in Broca's area and language lateralization. The structural asymmetries found in HG and the PT, in contrast, did not clearly and directly relate to language