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Shape Data (shape + data)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

Damage identification of structures with uncertain frequency and mode shape data

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 5 2002
Yong Xia
Abstract A statistical method with combined uncertain frequency and mode shape data for structural damage identification is proposed. By comparing the measured vibration data before damage or analytical finite element model of the intact structure with those measured after damage, the finite element model is updated so that its vibration characteristic changes are equal to the changes in the measured data as closely as possible. The effects of uncertainties in both the measured vibration data and finite element model are considered as random variables in model updating. The statistical variations of the updated finite element model are derived with perturbation method and Monte Carlo technique. The probabilities of damage existence in the structural members are then defined. The proposed method is applied to a laboratory tested steel cantilever beam and frame structure. The results show that all the damages are identified correctly with high probabilities of damage existence. Discussions are also made on the applicability of the method when no measurement data of intact structure are available. Copyright © 2002 John Wiley & Sons, Ltd. [source]

High-altitude migration of the diamondback moth Plutella xylostella to the U.K.: a study using radar, aerial netting, and ground trapping

ECOLOGICAL ENTOMOLOGY, Issue 6 2002
Jason W. Chapman
Abstract 1. The high-altitude wind-borne migration of the diamondback moth Plutella xylostella in the U.K. in 2000 was investigated (a) by direct monitoring of insect flight by vertical-looking radar and by aerial netting, and (b) through evidence of temporal variation in P. xylostella abundance deduced from a network of light traps. 2. Migrating P. xylostella were identified by a unique combination of size and shape data derived from the continuously operating vertical-looking radar. 3. Radar-detected migratory overflights correlated significantly with associated peaks in abundance of P. xylostella estimated by catches in a U.K.-wide light trap network; however the correlation was stronger when light trap catches were lagged by 1 day. 4. The first notable catches of P. xylostella in the U.K. occurred in early May, and were accompanied by migrations over the radar from the east. 5. Radar data and back-tracking indicated that a major wind-borne migration of P. xylostella from The Netherlands to southern England took place in early May, and that this was responsible for the establishment of the U.K. population. 6. The origin of early-season P. xylostella occurring in Britain is discussed. [source]

Geographical and taxonomic influences on cranial variation in red colobus monkeys (Primates, Colobinae): introducing a new approach to ,morph' monkeys

GLOBAL ECOLOGY, Issue 2 2009
Andrea Cardini
ABSTRACT Aim, To provide accurate but parsimonious quantitative descriptions of clines in cranial form of red colobus, to partition morphological variance into geographical, taxonomic and structured taxonomic components, and to visually summarize clines in multivariate shape data using a method which produces results directly comparable to both univariate studies of geographical variation and standard geometric morphometric visualization of shape differences along vectors. Location, Equatorial Africa. Methods, Sixty-four three-dimensional cranial landmarks were measured on 276 adult red colobus monkeys sampled over their entire distribution. Geometric morphometric methods were applied, and size and shape variables regressed onto geographical coordinates using linear and curvilinear models. Model selection was done using the second-order Akaike information criterion. Components of variation related to geography, taxon or their combined effect were partitioned using partial regresssion. Multivariate trends in clinal shape were summarized using principal components of predictions from regressions, plotting vector scores on maps as for univariate size, and visualizing differences along main axes of clinal shape variation using surface rendering. Results, Significant clinal variation was found in size and shape. Clines were similar in females and males. Trend surface analysis tended to be more accurate and parsimonious than alternative models in predicting morphology based on geography. Cranial form was relatively paedomorphic in East Africa and peramorphic in central Africa. Most taxonomic variation was geographically structured. However, taxonomic differences alone accounted for a larger proportion of total explained variance in shape (up to 40%) than in size (, 20%). Main conclusions, A strong cline explained most of the observed size variation and a significant part of the shape differences of red colobus crania. The pattern of geographical variation was largely similar to that previously reported in vervets, despite different habitat preferences (arboreal versus terrestrial) and a long period since divergence (c. 14,15 Myr). This suggests that some aspects of morphological divergence in both groups may have been influenced by similar environmental, geographical and historical factors. Cranial size is likely to be evolutionarily more labile and thus better reflects the influence of recent environmental changes. Cranial shape could be more resilient to change and thus better reflects phylogenetically informative differences. [source]

Development of the dentition: four-dimensional visualization and open questions concerning the morphogenesis of tooth form and occlusion

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 2003
RJ Radlanski
Structured Abstract Author, Radlanski RJ Objectives , The formation of the dental primordial should be visualized with special reference to characteristic differences for each single primordium. Until today, it has not been clear how traffic of the ameloblasts is controlled, how the folding pattern of the occlusal relief is generated or how the enamel production is terminated at the enamel surface. Design , Using computer-aided reconstructions from histological serial sections, the dental primordial were visualized and, using fractured enamel specimens, the traces of each single ameloblast were followed by means of scanning electron microscopy. In this way, the developmental movements of the inner enamel epithelium can be reconstructed. Results , Gathering morphological knowledge, three-dimensional polygon sets of shape data were input into a computer workstation and animated by means of the software Soft Image (Microsoft). Conclusions , The development of the human primary and permanent dentition was animated to simulate growth. [source]