Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 54 for “"grid cell"”.
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A neural inspired grid cell aid for robot intertial navigation.
… model of map formation and localization with grid cells to aid dead reckoning with an accelerometer and gyroscope to show grid cells are a viable aid in idiothetic navigation. The results show that the grid cell aided navigation systems shows better performance with longer paths and higher …
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Charting the hippocampal cognitive map: Investigating the emergence of grid cell and place cell firing patterns in novel and familiar environments
Hippocampal place cells comprise the main building blocks of the cognitive map which is used to encode our surroundings quickly and rapidly. Prominent theoretical models argue that place cells emerge via a linear summation of different grid cells from the medial entorhinal cortex. However, recent …
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Analysis of distribution maps from bird atlas data: dissimilarities between species, continuity within ranges and smoothing of distribution maps
… are compared over all quarter degree grid cells. Existing coefficients are not suitable for the comparison of distributions with different total areas and species with different mean reporting rates. In each grid cell the reliability of the reporting rates depends on the number of …
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Investigating the effect of energy dissipation on flotation kinetics in an oscillating grid flotation cell
… flotation kinetics of quartz in an oscillating grid flotation cell. Oscillating grids exhibit relatively isotropic and homogeneous turbulence, which cannot be achieved in standard impeller agitated flotation cells. Due to this they provide a potentially ideal environment in which to investigate …
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Skeleton-based visualization of massive voxel objects with network-like architecture
… with a discussion of homotopic thinning in the grid cell model. The grid cell model explicitly represents a cell complex built of faces, edges, and vertices shared between voxels. A characterization of pairs of cells to be deleted is much simpler than characterizations of simple voxels were …
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Optimal path planning for detection and classification of underwater targets using sonar
… state estimation falls under the occupancy grid framework, modeling the relationship between occupancy state of grid cells and sensor measurements, and allows for the consideration of statistical dependence between the occupancy state of each grid cell in the map. This is in direct contrast …
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Land Use of Conflicts in Tulsa County, Oklahoma: Urban Expansion Vs. Petroleum Development
… area. The study area was divided into a 160 acre grid cell system, and numerical scores were assigned to each grid cell, based upon their suitability for residential, commercial, or industrial land use. The results of this analysis showed that even though the variables considered in this study …
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Effect of Spatial Scale on Hydrologic Modeling in a Headwater Catchment
… same watershed using a series of different size grid cells. The first step in applying TOPMODEL to a watershed involves GIS analysis which results in a raster grid of elevations used for the calculation of the topographic index, ln(a/tan b). The hydrographs generated by TOPMODEL with each grid …
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Distributed Hydrologic Modeling of the Upper Roanoke River Watershed using GIS and NEXRAD
… improving hydrologic model accuracy. Grid based distributed models assume homogeneity of model parameters within each grid cell, raising the question of optimum grid scale to adequately and efficiently model the process in question. For a grid or raster based hydrologic model, as grid …
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Little Sac Woods Metro Forest, a Land Management Methodology and Plan
… use of maps and the area was divided into 320 grid cells of 2.5 acres each. Land management goals were determined for the area and criteria developed for six goals. Each grid cell was rated as to its suitability for the goal. The computer played an important role in the methodology. The …
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Mechanisms underlying spatial navigation
… First, I investigate the information conveyed by grid cells, whose firing fields tile the environment in a hexagonal grid. In doing so, they are thought to provide a static map of space. Current models of navigation propose that this static grid cell map is used to support navigation behaviours. …
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Effects of global climate change on the recruitment of Anchovy in the Southern Benguela upwelling system
… in Lasker events is expected at the Eastern Bank Grid Cell, which suggests that this area may become the preferred spawning habitat in the future. The Cape Town Grid Cell also shows suitable conditions in the future simulation for anchovy spawning and may thus become an alternative spawning …
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Organised variations in space and time in the hippocampal representation of location
… neurons in the hippocampal formation, including grid and place cells. The cognitive map also flexibly adjusts previous representations to reflect changes in a familiar environment. Several studies have demonstrated continuous spatial and temporal adjustments in how the cognitive map represents …
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Patterns in the landed catches and determinants of catch composition in the South African inshore trawl fishery
… trawl grounds were divided into 20' by 20' grid cells, which were used to aggregate the trawls and clustered into six groups at an 87% similarity. 7 | P a g e The landed catch composition per trip was influenced by the vessel (F(1, 21) = 32.7, p < 0.001, R2 = 0.31), year (F(1, 29) = 16.0, p …
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A machine learning model of Manhattan air pollution at high spatial resolution
… NARX model was created in MATLAB for each cell on a 250m square grid laid over Manhattan, for a total of 907 individual models across the city, for PM2 .5 , CO, NO2 , 03, and SO 2. In addition to standard meteorological inputs, data describing the distance and time traveled by taxis within …
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A Grid based Indoor Radiolocation Technique Based on Spatially Coherent Path Loss Model
This thesis presents a grid-based indoor radiolocation technique based on a Spatially Coherent Path Loss Model (SCPL). SCPL is a path loss model which characterizes the radio wave propagation in an environment by solely using Received Signal Strength (RSS) fingerprints. The propagation of the radio …
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Spatial and non-spatial patterns of genetic diversity in Neotropical bats
… calculated from 66 geographically distributed grid cells. Using a map of bat occurrence data, I estimated the average nucleotide diversity across bat species from each 300 x 300 km grid cell that contained at least three sequences of the same OTU. Across the same grid cells, I also compared …
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The elevation pyramid: a method for compressing elevation data
A quadtree-like representation for storing gridded elevation data is described. In its simplest form, the data structure is a pyramid with each node containing a two bit code. The root of the pyramid has associated with it the minimum elevation for the grid and the range (the greatest power of 2 …
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Socioeconomic topography : inner city economic development and Geographic Information Systems
… (GIS) has made it easier to apply raster (grid cell or bit pattern) analysis to studying urban spatial patterns. A map that shows socioeconomic phenomena via rasterization and smoothing processing is called "socioeconomic topography" here. Just as conventional topography shows us …
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The smooth is better than the rough : an exploitation of reporting rate information in Southern Africa bird atlas data
… and west-east coordinates relative to the target grid cell for which the prediction is being made. We explore some variants of our general smoothing approach that relates to the presentation of the smoothed distributions. The smoothed distributions of detection probabilities are presented as …
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