3,236,831 research outputs found
A Performance Analysis of Movement Patterns
This study investigates the differences in movement patterns followed by users navigating within a virtual environment. The analysis has been carried out between two groups of users, identified on the basis of their performance on a search task. Results indicate significant differences between efficient and inefficient navigators’ trajectories. They are related to rotational, translational and localised-landmarks behaviour. These findings are discussed in the light of theoretical outcomes provided by environmental psychology
Suite of simple metrics reveals common movement syndromes across vertebrate taxa
ecause empirical studies of animal movement are most-often site- and species-specific, we lack understanding of the level of consistency in movement patterns across diverse taxa, as well as a framework for quantitatively classifying movement patterns. We aim to address this gap by determining the extent to which statistical signatures of animal movement patterns recur across ecological systems. We assessed a suite of movement metrics derived from GPS trajectories of thirteen marine and terrestrial vertebrate species spanning three taxonomic classes, orders of magnitude in body size, and modes of movement (swimming, flying, walking). Using these metrics, we performed a principal components analysis and cluster analysis to determine if individuals organized into statistically distinct clusters. Finally, to identify and interpret commonalities within clusters, we compared them to computer-simulated idealized movement syndromes representing suites of correlated movement traits observed across taxa (migration, nomadism, territoriality, and central place foraging)
Stock market co-movement in the Caribbean
This paper investigates co-movement in five Caribbean stock markets (Barbados, Jamaica and Trinidad and Tobago, The Bahamas and Guyana) using common factor analysis. The common factors are obtained using principal component analysis and therefore account for the maximum portion of the variance present in the stock exchanges investigated. We break our analysis down and test for co-movement in different periods so as to ascertain any changes that have taken place from one period to the next. In particular we examine 10-year, 5-year and 3-year periods. We also specify a vector autoregression model and test for co-movement between the five markets during the sample period through impulse response functions. Both of our tests fail to find any evidence of co-movement between the exchanges over the entire sample period. However, we find evidence of periodic co-movement, particularly between exchanges in Barbados, Jamaica and Trinidad and Tobago
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Exploratory movement analysis and report building with R package stmove
Abstract Background As GPS tags and data loggers have become lighter, cheaper, and longer-lasting, there has been a growing influx of data on animal movement. Simultaneously, methods of analyses and software to apply such methods to movement data have expanded dramatically. Even so, for many interdisciplinary researchers and managers without familiarity with the field of movement ecology and the open-source tools that have been developed, the analysis of movement data has remained an overwhelming challenge. Description Here we present stmove , an R package designed to take individual relocation data and generate a visually rich report containing a set of preliminary results that ecologists and managers can use to guide further exploration of their data. Not only does this package make report building and exploratory data analysis (EDA) simple for users who may not be familiar with the extent of available analytical tools, but it sets forth a framework of best practice analyses, which offers a common starting point for the interpretation of terrestrial movement data. Results Using data from African elephants ( Loxodonta africana ) collected in southern Africa, we demonstrate stmove ’s report building function through the main analyses included: path visualization, primary statistic calculation, summary in space and time, and space-use construction. Conclusions The stmove package provides consistency and increased accessibility to managers and researchers who are interested in movement analysis but who may be unfamiliar with the full scope of movement packages and analytical tools. If widely adopted, the package will promote comparability of results across movement ecology studies
Intervention in tough-constructions revisited
Abstract
In this paper, we subject to closer scrutiny one particularly influential recent argument in favour of the long-movement analysis of tough-constructions. Hartman (2011, 2012a, 2012b) discovered that experiencer PPs lead to ungrammaticality in tough-constructions, but not in expletive constructions. He attributes this ungrammaticality to defective intervention of A-movement, a movement step crucially postulated only in the long-movement analysis. He takes this as evidence that tough-constructions are derived via long movement. We make the novel observation that a PP intervention effect analogous to that in tough-constructions also arises in constructions that do not involve A-movement, namely pretty-predicate constructions and gapped degree phrases. Consequently, the intervention effect does not provide an argument for an A-movement step in tough-constructions or for the long-movement analysis, but rather for the base-generation analysis. We develop a uniform account of the intervention effects as a semantic-type mismatch. In particular, we propose that what unifies tough-constructions, pretty-predicate constructions, and gapped degree phrases is that they all have an embedded clause that is a null-operator structure. Introducing an experiencer PP into these constructions creates an irresolvable semantic-type mismatch. As such, we argue for a reassessment of what appears to be a syntactic locality constraint as an incompatibility in the semantic composition
Analysis of thermal stress and metal movement during welding
Objectives of study were: investigation of temperature changes caused by welding arc with analysis of temperature distribution; development of system of mathematical statements describing thermal stresses and plastic strains during welding; and development of system of mathematical solutions and computer programs for one-dimensional analysis
On the Assessment of Stability and Patterning of Speech Movements
Speech requires the control of complex movements of orofacial structures to produce dynamic variations in the vocal tract transfer function. The nature of the underlying motor control processes has traditionally been investigated by employing measures of articulatory movements, including movement amplitude, velocity, and duration, at selected points in time. An alternative approach, first used in the study of limb motion, is to examine the entire movement trajectory over time. A new approach to speech movement trajectory analysis was introduced in earlier work from this laboratory. In this method, trajectories from multiple movement sequences are time- and amplitude-normalized, and the STI (spatiotemporal index) is computed to capture the degree of convergence of a set of trajectories onto a single, underlying movement template. This research note describes the rationale for this analysis and provides a detailed description of the signal processing involved. Alternative interpolation procedures for time-normalization of kinematic data are also considered
Results of Jack Mackerel tagging study, 1971-75
Methods and materials used to tag and recapture jack mackerel, Trachurus symmetricus, off the coast of southern Ca1ifornia and Baja California, Mexico, are described. Tagging, recapture, and movement data resulting from this program are reported. Analysis of these data indicates substantial movement of jack mackerel within the range of the California
fishery and suggests a seasonal inshore-offshore movement
pattern. (13pp.
Path, theme and narrative in open plan exhibition settings
Three arguments are made based on the analysis of science exhibitions. First,sufficiently refined techniques of spatial analysis allow us to model the impact oflayout upon visitors' paths, even in moderately sized open plans which allow almostrandom patterns of movement and relatively unobstructed visibility. Second, newlydeveloped or adapted techniques of analysis allow us to make a transition frommodeling the mechanics of spatial movement (the way in which movement is affectedby the distribution of obstacles and boundaries), to modeling the manner in whichmovement might register additional aspects of visual information. Third, theadvantages of such purely spatial modes of analysis extend into providing us with asharper understanding of some of the pragmatic constrains within which exhibitioncontent is conceived and designed
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