Search results for "Spatial"
showing 10 items of 2121 documents
Statistical analysis of latency outcomes in behavioral experiments
2011
In experimental designs of animal models, memory is often assessed by the time for a performance measure to occur (latency). Depending on the cognitive test, this may be the time it takes an animal to escape to a hidden platform (water maze), an escape tunnel (Barnes maze) or to enter a dark component (passive avoidance test). Latency outcomes are usually statistically analyzed using ANOVAs. Besides strong distributional assumptions, ANOVA cannot properly deal with animals not showing the performance measure within the trial time, potentially causing biased and misleading results. We propose an alternative approach for statistical analyses of latency outcomes. These analyses have less distr…
Analysis of the German Commuter Network Period 2013 -2021
2023
Understanding the behavior of commuters is crucial as the number of commuters steadily rises, causing significant traffic congestion in many cities. Indeed, commuter behavior is vital in city and transport planning and policy-making. Previous studies have investigated various factors that may impact commuting decisions. Still, these studies are often limited by the scale of data examined, including time duration, space, and the number of commuters. To address this gap, we gathered large-scale inter-city commuting data in Germany and analyzed the weighted commuting network from 2013 to 2021. This work relies on publicly available data so that the results can be reproduced.
Urban densities and economic analyse of residentials choices
2016
The thesis is focused on urban growth control challenge through the Compact City model and its key spatial characteristic: the density. This work deals both with a theoretical, methodological and empirical approach. First, we place ourselves in the theoretical framework of Urban Economic addressing agents’ location choices. We mobilize these theories to identify the key determinants of residential location (employment center, spatial amenities, housing’s service) and analyze the spatial organization that follows (dense or spread). This literature leads us to consider different types of density: structural density, population density and social density. This thesis highlights various methodo…
Minimum-cost distances in spatial analysis
1988
An axiomatic approach to distance is developed which focuses on thosebehavioral concepts of distance related to movement in space. In particular,spatial movement by behaving units is postulated to involve a choice fromamong some set of abstract trips in space, and implicitly, to involve theminimization of some relevant notion of trip costs. In this context, therelevant behavioral notion of distance in space is taken to be theminimum-cost distance generated by this choice process. These trip-costconcepts extend the classical notions of paths, path lengths, and shortestpaths in metric spaces. Hence many of the analytical results of the paperinvolve extensions of classical shortest-path distan…
Effects of distance and scale dependence in geographical models of cities and territories
2019
International audience; This third chapter questions the essential role of distance and scale dependence in models to analyzing the spatial configuration of human settlements and activities, as well as the processes that lead to their evolution, with reference to urban or regional study areas. The subject of study therefore concerns both the form of human settlements and the actions of people (individuals, groups) in their territory (or territories). A human settlement consists of the materialization in space-the physical inscription-of one or more human activities. It is characterized by a certain degree of sustainability. It can be a group of a few buildings or a larger group of thousands…
Virtual Reality Based Simulators for Neurosurgeons - What We Have and What We Hope to Have in the Nearest Future
2018
High levels of manual skills, good visual-motor coordination, excel‐lent imagination and spatial awareness are the main factors determining the success of neurosurgeons. Proficiency in neurosurgical skills used to be acquired through hands-on training in cadaver labs and in real operating theatres under master neurosurgeon supervision. Most recently, virtual reality (VR) and augmented reality (AR) computer simulations have also been considered as tools for education in the neurosurgical training. The authors review existing solutions and present their own concept of a simulator which could become the useful tool for planning, simulation and training of a specific neurosurgical procedure usi…
Land Surface Temperature
2019
Abstract An introduction to the chapter on Land Surface Temperature (LST). The basic thermal infrared theory is presented with example algorithms for the retrieval of LST and emissivity data are described in the later section. Various methods to validate satellite Land Surface Temperature (LST) products exist, but the most accurate and conclusive method is the direct comparison against in situ LST obtained from spatially representative radiance measurements over homogeneous sites. Some validation results and insights found in the literature are provided and the determination of in situ emissivity and LST with thermal infrared field radiometers is explained. The chapter concludes with an exa…
A measurement-based channel model for vehicular communications in tunnels
2014
Wireless Communications and Networking Conference (WCNC), 2014 IEEE, Istanbul, TURQUIE, 06-/04/2014 - 09/04/2014; In this paper, we present a new version of the iterative nonlinear least square approximation (INLSA) algorithm for the design of measurement-based channel simulators. The proposed method aims to match the time-variant impulse response (TVIR) of the simulation model to that of the measured channel. The propagation delays are discerned directly from the measurements, whereas the gains, the Doppler frequencies, and the phases are computed iteratively by minimizing a matching error norm. We evaluate the performance of the proposed method in terms of the approximation of the transfe…
On the Statistical Properties of the Capacity of Spatially Correlated Nakagami-M MIMO Channels
2008
This paper studies the statistical properties of the channel capacity of spatially correlated Nakagami-m multiple- input multiple-output (MIMO) channels. We have derived closed- form expressions for the probability density function (PDF), the cumulative distribution function (CDF), the level-crossing rate (LCR), and the average duration of fades (ADF) of the lower bound on the channel capacity. In order to study the impact of the spatial correlation on the channel capacity, the analysis of the statistical properties of the channel capacity is carried out for different receiver antenna spacings. It is observed that the antenna spacing has a significant influence on the spread and maximum val…
The Impact of Shadowing and the Severity of Fading on the First and Second Order Statistics of the Capacity of OSTBC MIMO Nakagami-Lognormal Channels
2011
Published version of an article in Wireless Personal Communications (2011), 1-16. Also available from the publisher at http://dx.doi.org/10.1007/s11277-011-0275-x This article presents a thorough statistical analysis of the capacity of orthogonal space-time block coded (OSTBC) multiple-input multiple-output (MIMO) Nakagami- lognormal (NLN) channels. The NLN channel model allows to study the joint effects of fast fading and shadowing on the statistical properties of the channel capacity. We have derived exact analytical expressions for the probability density function (PDF), cumulative distribution function (CDF), level-crossing rate (LCR), and average duration of fades (ADF) of the capacity…