2020 ◽  
Author(s):  
Anna Nowakowska ◽  
Alasdair D F Clarke ◽  
Jessica Christie ◽  
Josephine Reuther ◽  
Amelia R. Hunt

We measured the efficiency of 30 participants as they searched through simple line segment stimuli and through a set of complex icons. We observed a dramatic shift from highly variable, and mostly inefficient, strategies with the line segments, to uniformly efficient search behaviour with the icons. These results demonstrate that changing what may initially appear to be irrelevant, surface-level details of the task can lead to large changes in measured behaviour, and that visual primitives are not always representative of more complex objects.


2005 ◽  
Author(s):  
J. C. Allen ◽  
R. E. Goshorn ◽  
B. Zeidler ◽  
A. A. Beex
Keyword(s):  
Phase 1 ◽  

Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 960
Author(s):  
Hudson D. Spangler ◽  
Miguel A. Simancas-Pallares ◽  
Jeannie Ginnis ◽  
Andrea G. Ferreira Zandoná ◽  
Jeff Roach ◽  
...  

The importance of visual aids in communicating clinical examination findings or proposed treatments in dentistry cannot be overstated. Similarly, communicating dental research results with tooth surface-level precision is impractical without visual representations. Here, we present the development, deployment, and two real-life applications of a web-based data visualization informatics pipeline that converts tooth surface-level information to colorized, three-dimensional renderings. The core of the informatics pipeline focuses on texture (UV) mapping of a pre-existing model of the human primary dentition. The 88 individually segmented tooth surfaces receive independent inputs that are represented in colors and textures according to customizable user specifications. The web implementation SculptorHD, deployed on the Google Cloud Platform, can accommodate manually entered or spreadsheet-formatted tooth surface data and allows the customization of color palettes and thresholds, as well as surface textures (e.g., condition-free, caries lesions, stainless steel, or ceramic crowns). Its current implementation enabled the visualization and interpretation of clinical early childhood caries (ECC) subtypes using latent class analysis-derived caries experience summary data. As a demonstration of its potential clinical utility, the tool was also used to simulate the restorative treatment presentation of a severe ECC case, including the use of stainless steel and ceramic crowns. We expect that this publicly available web-based tool can aid clinicians and investigators deliver precise, visual presentations of dental conditions and proposed treatments. The creation of rapidly adjustable lifelike dental models, integrated to existing electronic health records and responsive to new clinical findings or planned for future work, is likely to boost two-way communication between clinicians and their patients.


2021 ◽  
Vol 13 (13) ◽  
pp. 2494
Author(s):  
Gaël Kermarrec ◽  
Niklas Schild ◽  
Jan Hartmann

T-splines have recently been introduced to represent objects of arbitrary shapes using a smaller number of control points than the conventional non-uniform rational B-splines (NURBS) or B-spline representatizons in computer-aided design, computer graphics and reverse engineering. They are flexible in representing complex surface shapes and economic in terms of parameters as they enable local refinement. This property is a great advantage when dense, scattered and noisy point clouds are approximated using least squares fitting, such as those from a terrestrial laser scanner (TLS). Unfortunately, when it comes to assessing the goodness of fit of the surface approximation with a real dataset, only a noisy point cloud can be approximated: (i) a low root mean squared error (RMSE) can be linked with an overfitting, i.e., a fitting of the noise, and should be correspondingly avoided, and (ii) a high RMSE is synonymous with a lack of details. To address the challenge of judging the approximation, the reference surface should be entirely known: this can be solved by printing a mathematically defined T-splines reference surface in three dimensions (3D) and modeling the artefacts induced by the 3D printing. Once scanned under different configurations, it is possible to assess the goodness of fit of the approximation for a noisy and potentially gappy point cloud and compare it with the traditional but less flexible NURBS. The advantages of T-splines local refinement open the door for further applications within a geodetic context such as rigorous statistical testing of deformation. Two different scans from a slightly deformed object were approximated; we found that more than 40% of the computational time could be saved without affecting the goodness of fit of the surface approximation by using the same mesh for the two epochs.


Author(s):  
Lei Yu ◽  
Zhihua Zhao ◽  
Gexue Ren

In this paper, a multibody dynamic model is established to simulate the dynamics and control of moving web with its guiding system, where the term moving web is used to describe thin materials, which are manufactured and processed in a continuous, flexible strip form. In contrast with available researches based on Eulerian description and beam assumption, webs are described by Lagrangian formulation with the absolute nodal coordinate formulation (ANCF) plate element, which is based on Kirchhoff’s assumptions that material normals to the original reference surface remain straight and normal to the deformed reference surface, and the nonlinear elasticity theory that accounts for large displacement, large rotation, and large deformation. The rollers and guiding mechanism are modeled as rigid bodies. The distributed frictional contact forces between rollers and web are considered by Hertz contact model and are evaluated by Gauss quadrature. The proportional integral (PI) control law for web guiding is also embedded in the multibody model. A series of simulations on a typical web-guide system is carried out using the multibody dynamics approach for web guiding system presented in this study. System dynamical information, for example, lateral displacement, stress distribution, and driving moment for web guiding, are obtained from simulations. Parameter sensitivity analysis illustrates the effect of influence variables and effectiveness of the PI control law for lateral movement control of web that are verified under different gains. The present Lagrangian formulation of web element, i.e., ANCF element, is not only capable of describing the large movement and deformation but also easily adapted to capture the distributed contact forces between web and rollers. The dynamical behavior of the moving web can be accurately described by a small number of ANCF thin plate elements. Simulations carried out in this paper show that the present approach is an effective method to assess the design of web guiding system with easily available desktop computers.


1906 ◽  
Vol 41 (3) ◽  
pp. 599-649 ◽  
Author(s):  
Chrystal

§ 1. The variations of the surface-level of lakes due to the direct action of wind and rain, and the smaller disturbances caused by surface waves, of small or moderate length, due to the action of the wind and the movement of boats and animals, must have been familiar phenomena at all times. The first accurately recorded observation, that lake-levels are subject to a rhythmic variation, similar in some respects to the ocean tides, seems to have been made at Geneva in 1730 by Fatio de Duillier, a well-known Swiss engineer. Owing to the peculiar configuration of the Geneva end of Lake Léman, these variations occasionally reach a magnitude of 5 or even 6 feet; and Duillier mentions that they were known in his time by the local name of “Seiches,” which has now been applied to rhythmic alterations of the level of lakes in general.


1992 ◽  
Vol 38 (1) ◽  
pp. 46-59 ◽  
Author(s):  
Robert M. Negrini ◽  
Jonathan O. Davis

AbstractPaleomagnetic records are used to correlate sedimentary sequences from pluvial Lakes Chewaucan and Russell in the western Great Basin. This correlation is the basis for age control in the relatively poorly dated sequence from Lake Chewaucan. The resulting chronology supports a lack of sedimentation in Lake Chewaucan during the interval 27,400 to 23,200 yr B.P., an assertion supported by the presence of a lag deposit at the corresponding stratigraphic horizon. Because the Lake Chewaucan outcrop (near Summer Lake, Oregon) is near the bottom of the lake basin, we conclude that Lake Chewaucan was at a lowstand during this time interval. The Chewaucan lowstand is coeval with the lowstand accompanying the Wizard's Beach Recession (isotope stage 3) previously seen in the geologic record from nearby pluvial Lake Lahontan. The ages of six tephra layers, including the Trego Hot Springs tephra, were also estimated using the paleomagnetic correlation. Together, the new age of the Trego Hot Springs tephra (21,800 yr B.P.) and the lake surface level prehistory of Lake Chewaucan imply a revised model for the lake surface level prehistory of Lake Lahontan. The revised model includes a longer duration for the Wizard's Beach Recession and the occurrence of a younger lowstand of short duration soon after the lowstand corresponding to the Wizard's Beach Recession.


A two-dimensional homogeneous random surface { y ( X )} is generated from another such surface { z ( X )} by a process of smoothing represented by y ( X ) = ∫ ∞ d u w ( u – X ) z ( u ), where w ( X ) is a deterministic weighting function satisfying certain conditions. The two-dimensional autocorrelation and spectral density functions of the smoothed surface { y ( X )} are calculated in terms of the corresponding functions of the reference surface { z ( X )} and the properties of the ‘footprint’ of the contact w ( X ). When the surfaces are Gaussian, the statistical properties of their peaks and summits are given by the continuous theory of surface roughness. If only sampled values of the surface height are available, there is a corresponding discrete theory. Provided that the discrete sampling interval is small enough, profile statistics calculated by the discrete theory should approach asymptotically those calculated by the continuous theory, but it is known that such asymptotic convergence may not occur in practice. For a smoothed surface { y ( X )} which is generated from a reference surface { z ( X )} by a ‘good’ footprint of finite area, it is shown in this paper that the expected asymptotic convergence does occur always, even if the reference surface is ideally white. For a footprint to be a good footprint, w ( X ) must be continuous and smooth enough that it can be differentiated twice everywhere, including at its edges. Sample calculations for three footprints, two of which are good footprints, illustrate the theory.


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