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Movement Parameters (movement + parameter)

Distribution by Scientific Domains

Life Sciences	75%

Selected Abstracts

Visyllable Based Speech Animation

COMPUTER GRAPHICS FORUM, Issue 3 2003
Sumedha Kshirsagar
Visemes are visual counterpart of phonemes. Traditionally, the speech animation of 3D synthetic faces involvesextraction of visemes from input speech followed by the application of co-articulation rules to generate realisticanimation. In this paper, we take a novel approach for speech animation , using visyllables, the visual counterpartof syllables. The approach results into a concatenative visyllable based speech animation system. The key contributionof this paper lies in two main areas. Firstly, we define a set of visyllable units for spoken English along withthe associated phonological rules for valid syllables. Based on these rules, we have implemented a syllabificationalgorithm that allows segmentation of a given phoneme stream into syllables and subsequently visyllables. Secondly,we have recorded the database of visyllables using a facial motion capture system. The recorded visyllableunits are post-processed semi-automatically to ensure continuity at the vowel boundaries of the visyllables. We defineeach visyllable in terms of the Facial Movement Parameters (FMP). The FMPs are obtained as a result of thestatistical analysis of the facial motion capture data. The FMPs allow a compact representation of the visyllables.Further, the FMPs also facilitate the formulation of rules for boundary matching and smoothing after concatenatingthe visyllables units. Ours is the first visyllable based speech animation system. The proposed technique iseasy to implement, effective for real-time as well as non real-time applications and results into realistic speechanimation. Categories and Subject Descriptors (according to ACM CCS): 1.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism [source]

Incorporating movement into models of grey seal population dynamics

JOURNAL OF ANIMAL ECOLOGY, Issue 3 2006
PHILIP J. HARRISON
Summary 1One of the most difficult problems in developing spatially explicit models of population dynamics is the validation and parameterization of the movement process. We show how movement models derived from capture,recapture analysis can be improved by incorporating them into a spatially explicit metapopulation model that is fitted to a time series of abundance data. 2We applied multisite capture,recapture analysis techniques to photo-identification data collected from female grey seals at the four main breeding colonies in the North Sea between 1999 and 2001. The best-fitting movement models were then incorporated into state-space metapopulation models that explicitly accounted for demographic and observational stochasticity. 3These metapopulation models were fitted to a 20-year time series of pup production data for each colony using a Bayesian approach. The best-fitting model, based on the Akaike Information Criterion (AIC), had only a single movement parameter, whose confidence interval was 82% less than that obtained from the capture,recapture study, but there was some support for a model that included an effect of distance between colonies. 4The state-space modelling provided improved estimates of other demographic parameters. 5The incorporation of movement, and the way in which it was modelled, affected both local and regional dynamics. These differences were most evident as colonies approached their carrying capacities, suggesting that our ability to discriminate between models should improve as the length of the grey seal time series increases. [source]

Non-optimal animal movement in human-altered landscapes

FUNCTIONAL ECOLOGY, Issue 6 2007
LENORE FAHRIG
Summary 1I synthesize the understanding of the relationship between landscape structure and animal movement in human-modified landscapes. 2The variety of landscape structures is first classified into four categories: continuous habitat, patchy habitat with high-quality matrix, patchy habitat with low-quality matrix, and patchy, ephemeral habitat. Using this simplification I group the range of evolved movement parameters into four categories or movement types. I then discuss how these movement types interact with current human-caused landscape changes, and how this often results in non-optimal movement. 3From this synthesis I develop a hypothesis that predicts the relative importance of the different population-level consequences of these non-optimal movements, for the four movement types. 4Populations of species that have inhabited landscapes with high habitat cover or patchy landscapes with low-risk matrix should have evolved low boundary responses and moderate to high movement probabilities. These species are predicted to be highly susceptible to increased movement mortality resulting from habitat loss and reduced matrix quality. 5In contrast, populations of species that evolved in patchy landscapes with high-risk matrix or dynamic patchy landscapes are predicted to be highly susceptible to decreased immigration and colonization success, due to the increasing patch isolation that results from habitat loss. 6Finally, I discuss three implications of this synthesis: (i) ,least cost path' analysis should not be used for land management decisions without data on actual movement paths and movement risks in the landscape; (ii) ,dispersal ability' is not simply an attribute of a species, but varies strongly with landscape structure such that the relative rankings of species' dispersal abilities can change following landscape alteration; and (iii) the assumption that more mobile species are more resilient to human-caused landscape change is not generally true, but depends on the structure of the landscape where the species evolved. [source]

Automated classification of Plasmodium sporozoite movement patterns reveals a shift towards productive motility during salivary gland infection

BIOTECHNOLOGY JOURNAL, Issue 6 2009
Stephan Hegge
Abstract The invasive stages of malaria and other apicomplexan parasites use a unique motility machinery based on actin, myosin and a number of parasite-specific proteins to invade host cells and tissues. The crucial importance of this motility machinery at several stages of the life cycle of these parasites makes the individual components potential drug targets. The different stages of the malaria parasite exhibit strikingly diverse movement patterns, likely reflecting the varied needs to achieve successful invasion. Here, we describe a Tool for Automated Sporozoite Tracking (ToAST) that allows the rapid simultaneous analysis of several hundred motile Plasmodium sporozoites, the stage of the malaria parasite transmitted by the mosquito. ToAST reliably categorizes different modes of sporozoite movement and can be used for both tracking changes in movement patterns and comparing overall movement parameters, such as average speed or the persistence of sporozoites undergoing a certain type of movement. This allows the comparison of potentially small differences between distinct parasite populations and will enable screening of drug libraries to find inhibitors of sporozoite motility. Using ToAST, we find that isolated sporozoites change their movement patterns towards productive motility during the first week after infection of mosquito salivary glands. [source]