Standard Coordinate System Research Articles

Determination of Deformations as a Result of Seismic Loadings on Two-Dimensional Reinforced Concrete Frame via Terrestrial Laser Scanners

Parallel to the technological developments, methods of defining locational data are changing. Laser scanners bring new advantages to engineering measurements and geodesy. Terrestrial laser scanners, which have previously been used in map engineering, have become an alternative method of measurement, especially for terrestrial applications. A common characteristic of deformation measurements is the requirement to measure the location of sufficient reference and object points established on the monitored structure. The number of reference and object points is limited when using classical methods, but not when using a laser scanner. Due to the limitations of classical geodetic survey methods, such as difficulty of application, high costs and low production speed, the present study applied ground laser scanners to deformation monitoring. A two-dimensional (2D) deformation survey was made of a concrete frame placed on a loading wall. Cartesian coordinates, derived from survey and evaluations, were converted into a standard coordinate system using the Molodensky–Badekas 3D similarity transformation. Student’s t test has been used to determine whether it was significant with the difference of coordinates or not. The deformation amounts and directions obtained from the electronic tachymeter and ground laser scanners were found to be very similar.

Quasi-local energy and the choice of reference

A quasi-local energy for Einstein's general relativity is defined by the value of the preferred boundary term in the covariant Hamiltonian formalism. The boundary term depends upon a choice of reference and a time-like displacement vector field (which can be associated with an observer) on the boundary of the region. Here, we analyze the spherical symmetric cases. For the obvious analytic choice of reference based on the metric components, we find that this technique gives the same quasi-local energy values using several standard coordinate systems and yet can give different values in some other coordinate systems. For the homogeneous-isotropic cosmologies, the energy can be non-positive, and one case which is actually flat space has a negative energy. As an alternative, we introduce a way to determine the choice of both the reference and displacement by extremizing the energy. This procedure gives the same value for the energy in different coordinate systems for the Schwarzschild space, and a non-negative value for the cosmological models, with zero energy for the dynamic cosmology which is actually Minkowski space. The time-like displacement vector comes out to be the dual mean curvature vector of the two-boundary.

Elastodynamic Scalar Potential Functions in Cylindrical Coordinate Systems

The aim of this paper is to present scalar potential functions for three-dimensional elastodynamic problems in transversely isotropic media defined by different cylindrical coordinate systems. To do so, the standard cylindrical coordinate system, elliptical cylindrical coordinate system and parabolic cylindrical coordinate system are considered. By virtue of Poisson’s representation, Lame solution and Chadwick-Trowbridge, the completeness of such representations is addressed. The representations given here are useful in the study of wave scattering from the circular, elliptical and parabolic edges.

Transfer Equation in General Curvilinear Coordinates

Abstract The differential operator of the monochromatic polarized radiative transfer equation is studied in case of statistically homogeneous turbid medium in Euclidean three-dimensional space, with arbitrary curvilinear coordinate system defined in it. An apparent rotation of the polarization plane along the light ray with respect to the chosen polarization reference plane generally takes place, due to purely geometric reasons. Using methods of tensor analysis, analytic expressions for the differential operator of the transfer equation depending on the components of the metric tensor and their derivatives are found. Considerable simplifications take place if the coordinate system is orthogonal. As an example, the differential operator of the vector radiative transfer equation in both elliptical conical coordinate system and oblate spheroidal coordinate system is written down. Nonstandard parameterization of standard elliptical conical coordinate system is proposed.

Methods of studying breast motion in sports bras: a review

There is exponentially increasing number of research publications studying breast motion in sports bras. However, there are large varieties of their methods and findings. To critically evaluate the consistency and limitations of previous breast motion studies, a systematic review of all articles on breast motion in sports bras was performed. A total of 17 fully extracted studies included 216 subjects, aged from 20 to 60 with bra cup sizes from A to J. They participated in only four types of activities with or without bras, but not in randomized controlled trials. Most studies focused on the vertical nipple movements, but seldom examined the three-dimensional breast velocity, acceleration, and trajectory. The sample sizes and the types of activities were limited. The reference frames were not stable in most studies. To study the realistic breast movements in the future, a standardized local coordinate system will be needed.

Esophageal Acid Exposure Alters the Functional Connectivity of the Deglutition Network

Background & Aim: Early studies using functional MRI (fMRI) have demonstrated that volitional swallow is associated with activation of a number of cortical areas (middle cingulate gyrus, ventrolateral prefrontal cortex, ventrolateral sensory/motor cortices andmiddle insula), which collectively represent the “cortical swallowing network” (CSN). Although the activation of these regions has been reported in the literature, the reproducibility of these activations has not been systematically studied. The aim of our study is to investigate the reproducibility of the CSN across different fMRI sessions. Methods: We studied 16 young right-handed healthy volunteers utilizing a standard paradigm driven fMRI protocol and analyzed with an event-related analysis technique. Echo-planar images were obtained during two identical nine minute scans across different sessions while twenty-one dry swallows were performed by visual cues in random intervals. Physiologic circulatory and respiratory-related signal changes were removed retrospectively. Functional images were then aligned, registered (12 degrees of freedom), and mapped stereotaxically to the standard coordinate system. Generalized linear model was then used to remove undesirable signal changes correlated with motion, white matter and cerebrospinal fluid. Finally, the second order group random mixed-effect multilevel analysis was performed to identify active cortical regions. Clusters with p<0.01 corrected for multiple comparisons were considered significant. The number of activated voxels (3.75x3.75x4 mm3) along with their average and peak percent signal change within each cluster was reported and compared between the two study sessions in order to determine the correlation co-efficient. Results: All subjects showed significant and clustered activity within the deglutition network during both scans. Activity within the right precuneus and supplementary area were not reproducible. Overall, the percent fMRI signal change and the number of activated voxels were similar between the two studies with correlation co-efficients r=0.88 and r=0.86, respectively (p<0.0001). Activity within the right precuneus and supplementary area were not reproducible. Within the remaining 20 regions of interest (ROI), the overlap of activity maps across both sessions showed that the center of the activated clusters was within 6.3±4.8 mm (less than two voxels). The difference in maximum activated voxel activity was 9.7±5.9 mm. Conclusions: fMRI activity maps as well as percent signal change and number of voxels activated by volitional swallow in the CSN are reproducible between studies.

Participation of the Default Mode Network in the Cortical Control of Volitional Swallowing

Background & Aim: Early studies using functional MRI (fMRI) have demonstrated that volitional swallow is associated with activation of a number of cortical areas (middle cingulate gyrus, ventrolateral prefrontal cortex, ventrolateral sensory/motor cortices andmiddle insula), which collectively represent the “cortical swallowing network” (CSN). Although the activation of these regions has been reported in the literature, the reproducibility of these activations has not been systematically studied. The aim of our study is to investigate the reproducibility of the CSN across different fMRI sessions. Methods: We studied 16 young right-handed healthy volunteers utilizing a standard paradigm driven fMRI protocol and analyzed with an event-related analysis technique. Echo-planar images were obtained during two identical nine minute scans across different sessions while twenty-one dry swallows were performed by visual cues in random intervals. Physiologic circulatory and respiratory-related signal changes were removed retrospectively. Functional images were then aligned, registered (12 degrees of freedom), and mapped stereotaxically to the standard coordinate system. Generalized linear model was then used to remove undesirable signal changes correlated with motion, white matter and cerebrospinal fluid. Finally, the second order group random mixed-effect multilevel analysis was performed to identify active cortical regions. Clusters with p<0.01 corrected for multiple comparisons were considered significant. The number of activated voxels (3.75x3.75x4 mm3) along with their average and peak percent signal change within each cluster was reported and compared between the two study sessions in order to determine the correlation co-efficient. Results: All subjects showed significant and clustered activity within the deglutition network during both scans. Activity within the right precuneus and supplementary area were not reproducible. Overall, the percent fMRI signal change and the number of activated voxels were similar between the two studies with correlation co-efficients r=0.88 and r=0.86, respectively (p<0.0001). Activity within the right precuneus and supplementary area were not reproducible. Within the remaining 20 regions of interest (ROI), the overlap of activity maps across both sessions showed that the center of the activated clusters was within 6.3±4.8 mm (less than two voxels). The difference in maximum activated voxel activity was 9.7±5.9 mm. Conclusions: fMRI activity maps as well as percent signal change and number of voxels activated by volitional swallow in the CSN are reproducible between studies.

Reliability and Reproducibility of FMRI Activity in the Cortical Swallowing Network

Background & Aim: Early studies using functional MRI (fMRI) have demonstrated that volitional swallow is associated with activation of a number of cortical areas (middle cingulate gyrus, ventrolateral prefrontal cortex, ventrolateral sensory/motor cortices andmiddle insula), which collectively represent the “cortical swallowing network” (CSN). Although the activation of these regions has been reported in the literature, the reproducibility of these activations has not been systematically studied. The aim of our study is to investigate the reproducibility of the CSN across different fMRI sessions. Methods: We studied 16 young right-handed healthy volunteers utilizing a standard paradigm driven fMRI protocol and analyzed with an event-related analysis technique. Echo-planar images were obtained during two identical nine minute scans across different sessions while twenty-one dry swallows were performed by visual cues in random intervals. Physiologic circulatory and respiratory-related signal changes were removed retrospectively. Functional images were then aligned, registered (12 degrees of freedom), and mapped stereotaxically to the standard coordinate system. Generalized linear model was then used to remove undesirable signal changes correlated with motion, white matter and cerebrospinal fluid. Finally, the second order group random mixed-effect multilevel analysis was performed to identify active cortical regions. Clusters with p<0.01 corrected for multiple comparisons were considered significant. The number of activated voxels (3.75x3.75x4 mm3) along with their average and peak percent signal change within each cluster was reported and compared between the two study sessions in order to determine the correlation co-efficient. Results: All subjects showed significant and clustered activity within the deglutition network during both scans. Activity within the right precuneus and supplementary area were not reproducible. Overall, the percent fMRI signal change and the number of activated voxels were similar between the two studies with correlation co-efficients r=0.88 and r=0.86, respectively (p<0.0001). Activity within the right precuneus and supplementary area were not reproducible. Within the remaining 20 regions of interest (ROI), the overlap of activity maps across both sessions showed that the center of the activated clusters was within 6.3±4.8 mm (less than two voxels). The difference in maximum activated voxel activity was 9.7±5.9 mm. Conclusions: fMRI activity maps as well as percent signal change and number of voxels activated by volitional swallow in the CSN are reproducible between studies.

Does Biofeedback Therapy Modulate Anorectal (Gut)-Brain Axis in Patients With Dyssynergic Defecation?

Background & Aim: Early studies using functional MRI (fMRI) have demonstrated that volitional swallow is associated with activation of a number of cortical areas (middle cingulate gyrus, ventrolateral prefrontal cortex, ventrolateral sensory/motor cortices andmiddle insula), which collectively represent the “cortical swallowing network” (CSN). Although the activation of these regions has been reported in the literature, the reproducibility of these activations has not been systematically studied. The aim of our study is to investigate the reproducibility of the CSN across different fMRI sessions. Methods: We studied 16 young right-handed healthy volunteers utilizing a standard paradigm driven fMRI protocol and analyzed with an event-related analysis technique. Echo-planar images were obtained during two identical nine minute scans across different sessions while twenty-one dry swallows were performed by visual cues in random intervals. Physiologic circulatory and respiratory-related signal changes were removed retrospectively. Functional images were then aligned, registered (12 degrees of freedom), and mapped stereotaxically to the standard coordinate system. Generalized linear model was then used to remove undesirable signal changes correlated with motion, white matter and cerebrospinal fluid. Finally, the second order group random mixed-effect multilevel analysis was performed to identify active cortical regions. Clusters with p<0.01 corrected for multiple comparisons were considered significant. The number of activated voxels (3.75x3.75x4 mm3) along with their average and peak percent signal change within each cluster was reported and compared between the two study sessions in order to determine the correlation co-efficient. Results: All subjects showed significant and clustered activity within the deglutition network during both scans. Activity within the right precuneus and supplementary area were not reproducible. Overall, the percent fMRI signal change and the number of activated voxels were similar between the two studies with correlation co-efficients r=0.88 and r=0.86, respectively (p<0.0001). Activity within the right precuneus and supplementary area were not reproducible. Within the remaining 20 regions of interest (ROI), the overlap of activity maps across both sessions showed that the center of the activated clusters was within 6.3±4.8 mm (less than two voxels). The difference in maximum activated voxel activity was 9.7±5.9 mm. Conclusions: fMRI activity maps as well as percent signal change and number of voxels activated by volitional swallow in the CSN are reproducible between studies.

Maximal admissible faces and asymptotic bounds for the normal surface solution space

The enumeration of normal surfaces is a key bottleneck in computational three-dimensional topology. The underlying procedure is the enumeration of admissible vertices of a high-dimensional polytope, where admissibility is a powerful but non-linear and non-convex constraint. The main results of this paper are significant improvements upon the best known asymptotic bounds on the number of admissible vertices, using polytopes in both the standard normal surface coordinate system and the streamlined quadrilateral coordinate system. To achieve these results we examine the layout of admissible points within these polytopes. We show that these points correspond to well-behaved substructures of the face lattice, and we study properties of the corresponding “admissible faces”. Key lemmata include upper bounds on the number of maximal admissible faces of each dimension, and a bijection between the maximal admissible faces in the two coordinate systems mentioned above.

Development of a simulation system in mandibular orthognathic surgery based on integrated three-dimensional data

PurposeSurgical simulation should reflect the 3D movement of dentition and the resultant movement of the osteotomized segments, which can influence surgical outcome. The present study was aimed at developing a new simulation system that enables virtual osteotomy of a given surgical situation and evaluation of the bony interference between the osteotomized segments of the mandible.Subjects and methodsThe data of 3D computer tomography (CT) for maxillomandibular dental casts were integrated into the standard coordinates of a 3D cephalogram. To evaluate the accuracy of the system, measurement errors of the 3D CT virtual model from a dry skull were compared with the computer simulation system and a contact-type 3D digitizer. To examine the clinical accessibility, 15 mandibular prognathism patients with mild to severe asymmetry were evaluated with the simulation program.ResultsThe average error of measurement in all directions was 1.31 mm. It was possible to simulate various osteotomy procedures by conversion of the 3D coordinates of the dental cast and CT data into the standard coordinate system of a 3D cephalogram. Using this simulation system, it was possible to prevent condylar torque or segment malpositioning by removing the bony interference visualized by a 3D virtual model.ConclusionA new system, which enables the precise visualization of osteotomized segments and calculation of bony interference, was proposed in the present study. This new system provides an acceptable precision of treatment planning of orthognathic surgery, especially for facial asymmetry.

Erratum: “A complete set of material properties of single domain 0.26Pb(In1/2Nb1/2)O3–0.46Pb(Mg1/3Nb2/3)O3–0.28PbTiO3 single crystals” [Appl. Phys. Lett. 96, 012907 (2010)

[This corrects the article on p. 012907 in vol. 96.].

Parametric Estimation of Affine Transformations: An Exact Linear Solution

We consider the problem of estimating the geometric deformation of an object, with respect to some reference observation on it. Existing solutions, set in the standard coordinate system imposed by the measurement system, lead to high-dimensional, non-convex optimization problems. We propose a novel framework that employs a set of non-linear functionals to replace this originally high dimensional problem by an equivalent problem that is linear in the unknown transformation parameters. The proposed solution includes the case where the deformation relating the observed signature of the object and the reference template is composed both of the geometric deformation due to the affine transformation of the coordinate system and a constant amplitude gain. The proposed solution is unique and exact and is applicable to any affine transformation regardless of its magnitude.

Utilization of Three-Dimensional Computed Tomography for Craniofacial Phenotypic Analysis in Children With Velocardiofacial Syndrome

To analyze variants of the craniofacial phenotypes in children with velocardiofacial syndrome (VCFS) and children with cleft palates with a new protocol of landmarks using a three-dimensional computed tomography (CT)-reconstructed model in a cross-sectional group experimental design. We present a retrospectively reviewed case series of 21 patients with VCFS, verified by short-tandem repeat techniques, and 20 children with cleft palate with age- and sex-matched controls from the Craniofacial Cleft Department of Oral and Maxillofacial Surgery of the 9th Shanghai People's Hospital. The records during the period between January 2005 and December 2008 were analyzed. The sample population of 41 children in this study was scanned with spiral CT. These images were reconstructed into three-dimensional models by SimPlant 11.2 and were analyzed with a new protocol of landmarks to test the variants of craniofacial phenotypes. All of the children with VCFS demonstrated velopharyngeal incompetence and craniofacial deformities. Measurements in the standard coordinate system demonstrated significant shorter cranial base, cervical vertebrae, longer maxilla height, and palatal angle. For the velopharyngeal variants, greater depth but lesser width of the pharyngeal cavity was shown in the VCFS group. Three-dimensional CT can provide precise data on craniofacial variants in children with distinctive morphologic features of VCFS.

Matchmaking for online games and other latency-sensitive P2P systems

The latency between machines on the Internet can dramatically affect users' experience for many distributed applications. Particularly, in multiplayer online games, players seek to cluster themselves so that those in the same session have low latency to each other. A system that predicts latencies between machine pairs allows such matchmaking to consider many more machine pairs than can be probed in a scalable fashion while users are waiting. Using a far-reaching trace of latencies between players on over 3.5 million game consoles, we designed Htrae, a latency prediction system for game matchmaking scenarios. One novel feature of Htrae is its synthesis of geolocation with a network coordinate system. It uses geolocation to select reasonable initial network coordinates for new machines joining the system, allowing it to converge more quickly than standard network coordinate systems and produce substantially lower prediction error than state-of-the-art latency prediction systems. For instance, it produces 90th percentile errors less than half those of iPlane and Pyxida. Our design is general enough to make it a good fit for other latency-sensitive peer-to-peer applications besides game matchmaking.

Visualization of spherical data by Yin–Yang grid

Abstract Visualization in the spherical geometry is ubiquitous in geophysical data processing. For the spherical visualization, the commonly used spherical polar coordinate system is not ideal due to its grid convergence nature near the poles. We propose to use a spherical overset grid system called Yin–Yang grid as the base grid system of the spherical visualization. The convergence-free nature of the Yin–Yang grid leads to a balanced data distribution and effective visualization processing in a sphere. The Yin–Yang grid is already used in various geophysical simulations including the geodynamo and mantle convection in the spherical geometry. Data produced by the Yin–Yang grid can be, and should be, visualized directly on the same Yin–Yang grid system without any data remapping. Since the component grid of the Yin–Yang grid is a part of (or low latitude region of) the standard spherical polar coordinate system, it is straightforward to convert an existing spherical visualization tool based on the spherical polar coordinates into a tool based on the Yin–Yang grid.

Typical dipole locations can be estimated using averaged somatosensory-evoked potentials and a standard brain model

It is reasonable to hypothesize that dipoles estimated from grand averaged event-related potentials based on summed-up data obtained from multiple subjects and standard head models could correspond to typical brain regions associated to a particular event. Six healthy subjects were enrolled in a study to test this hypothesis. We estimated dipoles from somatosensory-evoked potentials (SEP) elicited by electrical stimulation to the left median nerve. We also created individual three-layered (scalp, skull, and brain) head models from each subject's magnetic resonance imaging scan, and dipoles were estimated from the individual averaged SEP with each individual head model. We then estimated dipoles using grand averaged SEP across all subjects on the standard head model created from the Montreal Neurological Institute (MNI) standard coordinate system brain template to compare the estimated dipoles located on our own head model and those on the MNI. The dipoles in the post-central gyrus were estimated from negative potentials at 20 ms from the grand averaged data incorporated with the MNI head model, corresponding to a typical location related to SEP stimulation. The results suggest the validity of estimating the dipole location from the grand averaged potential of all subjects with the MNI model if we focus on typical regions related to the task.

Probabilistic topography of human corpus callosum using cytoarchitectural parcellation and high angular resolution diffusion imaging tractography

The function of the corpus callosum (CC) is to distribute perceptual, motor, cognitive, learned, and voluntary information between the two hemispheres of the brain. Accurate parcellation of the CC according to fiber composition and fiber connection is of upmost important. In this work, population-based probabilistic connection topographies of the CC, in the standard Montreal Neurological Institute (MNI) space, are estimated by incorporating anatomical cytoarchitectural parcellation with high angular resolution diffusion imaging (HARDI) tractography. First, callosal fibers are extracted using multiple fiber assignment by continuous tracking algorithm based on q-ball imaging (QBI), on 12 healthy and young subjects. Then, the fiber tracts are aligned in the standard MNI coordinate system based on a tract-based transformation scheme. Next, twenty-eight Brodmann's areas on the surface of cortical cortex are registered to the MNI space to parcellate the aligned callosal fibers. Finally, the population-based topological subdivisions of the midsagittal CC to each cortical target are then mapped. And the resulting subdivisions of the CC that connect to the frontal and somatosensory associated cortex are also showed. To our knowledge, it is the first topographic subdivisions of the CC done using HARDI tractography and cytoarchitectonic information. In conclusion, this sophisticated topography of the CC may serve as a landmark to further understand the correlations between the CC, brain intercommunication, and functional cytoarchitectures.

Waxholm Space: Target Volumes for a Standard Coordinate System for the Mouse Brain

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A geometry-driven optical flow warping for spatial normalization of cortical surfaces.

Spatial normalization is frequently used to map data to a standard coordinate system by removing intersubject morphological differences, thereby allowing for group analysis to be carried out. The work presented in this paper is motivated by the need for an automated cortical surface normalization technique that will automatically identify homologous cortical landmarks and map them to the same coordinates on a standard manifold. The geometry of a cortical surface is analyzed using two shape measures that distinguish the sulcal and gyral regions in a multiscale framework. A multichannel optical flow warping procedure aligns these shape measures between a reference brain and a subject brain, creating the desired normalization. The partial differential equation that carries out the warping is implemented in a Euclidean framework in order to facilitate a multiresolution strategy, thereby permitting large deformations between the two surfaces. The technique is demonstrated by aligning 33 normal cortical surfaces and showing both improved structural alignment in manually labeled sulci and improved functional alignment in positron emission tomography data mapped to the surfaces. A quantitative comparison between our proposed surface-based spatial normalization method and a leading volumetric spatial normalization method is included to show that the surface-based spatial normalization performs better in matching homologous cortical anatomies.