Gravitational collapse in a single coordinate system

1995 ◽  
Vol 63 (11) ◽  
pp. 991-999 ◽  
Author(s):  
Ronald Gautreau ◽  
Jeffrey M. Cohen
Keyword(s):  
Coordinate System ◽  
Gravitational Collapse ◽  
Single Coordinate

scholarly journals Calibration of the Relative Orientation between Multiple Depth Cameras Based on a Three-Dimensional Target

Sensors ◽  
2019 ◽  
Vol 19 (13) ◽  
pp. 3008 ◽  
Author(s):  
Zhe Liu ◽  
Zhaozong Meng ◽  
Nan Gao ◽  
Zonghua Zhang
Keyword(s):  
Coordinate System ◽  
Camera Calibration ◽  
Three Dimensional ◽  
Field Of View ◽  
Depth Information ◽  
Depth Camera ◽  
Depth Cameras ◽  
Calibration Methods ◽  
3D Shape Reconstruction ◽  
Single Coordinate

Depth cameras play a vital role in three-dimensional (3D) shape reconstruction, machine vision, augmented/virtual reality and other visual information-related fields. However, a single depth camera cannot obtain complete information about an object by itself due to the limitation of the camera’s field of view. Multiple depth cameras can solve this problem by acquiring depth information from different viewpoints. In order to do so, they need to be calibrated to be able to accurately obtain the complete 3D information. However, traditional chessboard-based planar targets are not well suited for calibrating the relative orientations between multiple depth cameras, because the coordinates of different depth cameras need to be unified into a single coordinate system, and the multiple camera systems with a specific angle have a very small overlapping field of view. In this paper, we propose a 3D target-based multiple depth camera calibration method. Each plane of the 3D target is used to calibrate an independent depth camera. All planes of the 3D target are unified into a single coordinate system, which means the feature points on the calibration plane are also in one unified coordinate system. Using this 3D target, multiple depth cameras can be calibrated simultaneously. In this paper, a method of precise calibration using lidar is proposed. This method is not only applicable to the 3D target designed for the purposes of this paper, but it can also be applied to all 3D calibration objects consisting of planar chessboards. This method can significantly reduce the calibration error compared with traditional camera calibration methods. In addition, in order to reduce the influence of the infrared transmitter of the depth camera and improve its calibration accuracy, the calibration process of the depth camera is optimized. A series of calibration experiments were carried out, and the experimental results demonstrated the reliability and effectiveness of the proposed method.

GIS technologies for integrating cartographic materials into a single coordinate system

2019 ◽  
Author(s):  
O. Rodzinska ◽  
I. Perovych ◽  
L. Perovych ◽  
O. Ludchak
Keyword(s):  
Coordinate System ◽  
Gis Technologies ◽  
Single Coordinate

About determination of coordinates of sources of geomagnetic perturbations according to the world network of magnetic observatories

2020 ◽  
Author(s):  
Beibit Zhumabayev ◽  
Ivan Vassilyev ◽  
Vladimir Protsenko ◽  
Saltanat Zhumabayeva
Keyword(s):  
Coordinate System ◽  
Geomagnetic Storms ◽  
Magnetic Clouds ◽  
The World ◽  
Relationship Of ◽  
The Relationship ◽  
Geomagnetic Perturbations ◽  
Magnetic Observatories ◽  
Single Coordinate

<p>A method for determining the coordinates of geomagnetic perturbation sources based on joint data processing of the world network of magnetic observatories is proposed. A large statistical material showed the relationship of large geomagnetic storms with the interaction of two or more magnetic clouds formed as a result of coronal mass ejections. To determine the coordinates of the sources of perturbations, it is proposed to use the data of magnetic observatories of the "INTERMAGNET" international network, which has more than 100 observation points distributed around the world and equipped with modern identical hardware. The results of geomagnetic field measurement obtained by magnetic observatories are brought to a single coordinate system. It was achieved by rotation of the axes of local stations, which allows determining the coordinates of the sources of perturbations and evaluating the accuracy of specifying the coordinate system of each local observatory.</p>

scholarly journals Proposed single-zone map projection system for Turkey

2021 ◽  
Vol 112 (1) ◽  
pp. 35-45
Author(s):  
Faruk Yildirim ◽  
Fatih Kadi
Keyword(s):  
Coordinate System ◽  
Large Scale ◽  
Projection System ◽  
Map Projection ◽  
Map Projections ◽  
Coordinate Base ◽  
Processing Errors ◽  
First Time ◽  
East West ◽  
Single Coordinate

Abstract The coordinate base of the maps or sheets produced is the Universal Transversal Mercator (UTM) conformal projection, and it is not possible to work in a single coordinate system in Turkey. Therefore, a transition from UTM to other conformal projections is required. For the countries extending in an east–west UTM zone width like Turkey, composite projection (CP), a double standard paralleling Lambert Conformal Conic (LCC) and double map projections (DP) are used widely. However, this process causes increase in working load and processing errors by users. This study aims to determine a common projection system that can be used in the whole country. In this context, a composite projection from UTM and LCC projection has been defined for the first time. According to the results obtained, map projection CP with the least distortion values in both east–west and north–south directions has been chosen. With the CP selection, a single coordinate system has been determined for medium- and large-scale maps. Projection correction formulas, scale factor and false origin have been determined for map coordinates in CP. These distortions are obtained with a difference of less than 1 cm for 1 km long sides and less than 0.003″ for the azimuth value of this side, when the correction formulas are used.

scholarly journals COMPREHENSIVE ASSESSMENT OF THE EFFECTIVENESS OF THE DEVELOPMENT OF JOINT-STOCK COMPANIES IN THE BUILDING MATERIALS INDUSTRY

2021 ◽  
pp. 196-200
Author(s):  
Dekhkanov Sherzod Abdumutalibovich
Keyword(s):  
Coordinate System ◽  
Key Words ◽  
Building Materials ◽  
Comprehensive Assessment ◽  
Single Coordinate

The article discusses systems for the comprehensive assessment of the effectiveness of corporations, which allow linking various financial, production, personnel and other characteristics of corporations activities in a single coordinate system. KEY WORDS: Corporation, finance, production, personnel issues, descriptions of corporations, coordinates.

scholarly journals Motor learning of novel dynamics is not represented in a single global coordinate system: evaluation of mixed coordinate representations and local learning

2014 ◽  
Vol 111 (6) ◽  
pp. 1165-1182 ◽  
Author(s):  
Max Berniker ◽  
David W. Franklin ◽  
J. Randall Flanagan ◽  
Daniel M. Wolpert ◽  
Konrad Kording
Keyword(s):  
Coordinate System ◽  
Motor Performance ◽  
System Evaluation ◽  
Coordinate Frame ◽  
Global Coordinate System ◽  
Local Learning ◽  
Single System ◽  
Central Question ◽  
Coordinate Systems ◽  
Single Coordinate

Successful motor performance requires the ability to adapt motor commands to task dynamics. A central question in movement neuroscience is how these dynamics are represented. Although it is widely assumed that dynamics (e.g., force fields) are represented in intrinsic, joint-based coordinates (Shadmehr R, Mussa-Ivaldi FA. J Neurosci 14: 3208–3224, 1994), recent evidence has questioned this proposal. Here we reexamine the representation of dynamics in two experiments. By testing generalization following changes in shoulder, elbow, or wrist configurations, the first experiment tested for extrinsic, intrinsic, or object-centered representations. No single coordinate frame accounted for the pattern of generalization. Rather, generalization patterns were better accounted for by a mixture of representations or by models that assumed local learning and graded, decaying generalization. A second experiment, in which we replicated the design of an influential study that had suggested encoding in intrinsic coordinates (Shadmehr and Mussa-Ivaldi 1994), yielded similar results. That is, we could not find evidence that dynamics are represented in a single coordinate system. Taken together, our experiments suggest that internal models do not employ a single coordinate system when generalizing and may well be represented as a mixture of coordinate systems, as a single system with local learning, or both.

Evidence against a single coordinate system representation in the motor cortex

2006 ◽  
Vol 175 (2) ◽  
pp. 197-210 ◽  
Author(s):  
Wei Wu ◽  
Nicholas Hatsopoulos
Keyword(s):  
Motor Cortex ◽  
Coordinate System ◽  
System Representation ◽  
Single Coordinate

Electromagnetic Relations in a Single Coordinate System

1964 ◽  
Vol 32 (11) ◽  
pp. 879-883 ◽  
Author(s):  
Emerson M. Pugh
Keyword(s):  
Coordinate System ◽  
Single Coordinate

Reference Coordinate System Requirements for Geophysics

1975 ◽  
Vol 26 ◽  
pp. 87-92
Author(s):  
P. L. Bender
Keyword(s):  
Coordinate System ◽  
Polar Motion ◽  
Main Part ◽  
Measurement Techniques ◽  
Reference Points ◽  
Angular Motion ◽  
Coordinate Systems ◽  
Axis Of Rotation ◽  
The Earth ◽  
Fixed System

AbstractFive important geodynamical quantities which are closely linked are: 1) motions of points on the Earth’s surface; 2)polar motion; 3) changes in UT1-UTC; 4) nutation; and 5) motion of the geocenter. For each of these we expect to achieve measurements in the near future which have an accuracy of 1 to 3 cm or 0.3 to 1 milliarcsec.From a metrological point of view, one can say simply: “Measure each quantity against whichever coordinate system you can make the most accurate measurements with respect to”. I believe that this statement should serve as a guiding principle for the recommendations of the colloquium. However, it also is important that the coordinate systems help to provide a clear separation between the different phenomena of interest, and correspond closely to the conceptual definitions in terms of which geophysicists think about the phenomena.In any discussion of angular motion in space, both a “body-fixed” system and a “space-fixed” system are used. Some relevant types of coordinate systems, reference directions, or reference points which have been considered are: 1) celestial systems based on optical star catalogs, distant galaxies, radio source catalogs, or the Moon and inner planets; 2) the Earth’s axis of rotation, which defines a line through the Earth as well as a celestial reference direction; 3) the geocenter; and 4) “quasi-Earth-fixed” coordinate systems.When a geophysicists discusses UT1 and polar motion, he usually is thinking of the angular motion of the main part of the mantle with respect to an inertial frame and to the direction of the spin axis. Since the velocities of relative motion in most of the mantle are expectd to be extremely small, even if “substantial” deep convection is occurring, the conceptual “quasi-Earth-fixed” reference frame seems well defined. Methods for realizing a close approximation to this frame fortunately exist. Hopefully, this colloquium will recommend procedures for establishing and maintaining such a system for use in geodynamics. Motion of points on the Earth’s surface and of the geocenter can be measured against such a system with the full accuracy of the new techniques.The situation with respect to celestial reference frames is different. The various measurement techniques give changes in the orientation of the Earth, relative to different systems, so that we would like to know the relative motions of the systems in order to compare the results. However, there does not appear to be a need for defining any new system. Subjective figures of merit for the various system dependon both the accuracy with which measurements can be made against them and the degree to which they can be related to inertial systems.The main coordinate system requirement related to the 5 geodynamic quantities discussed in this talk is thus for the establishment and maintenance of a “quasi-Earth-fixed” coordinate system which closely approximates the motion of the main part of the mantle. Changes in the orientation of this system with respect to the various celestial systems can be determined by both the new and the conventional techniques, provided that some knowledge of changes in the local vertical is available. Changes in the axis of rotation and in the geocenter with respect to this system also can be obtained, as well as measurements of nutation.

2.2. Working Group 2: Conceptual Definitions of Reference Coordinate Systems for Earth Dynamics

1975 ◽  
Vol 26 ◽  
pp. 21-26
Keyword(s):  
Coordinate System ◽  
Working Group ◽  
General Character ◽  
Coordinate Systems ◽  
Reference Coordinate System ◽  
Group 2 ◽  
Definition Of ◽  
Earth Dynamics

An ideal definition of a reference coordinate system should meet the following general requirements:1. It should be as conceptually simple as possible, so its philosophy is well understood by the users.2. It should imply as few physical assumptions as possible. Wherever they are necessary, such assumptions should be of a very general character and, in particular, they should not be dependent upon astronomical and geophysical detailed theories.3. It should suggest a materialization that is dynamically stable and is accessible to observations with the required accuracy.

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