Finding Axes of Symmetry From Potential Fields

2004 ◽  
Vol 13 (12) ◽  
pp. 1559-1566 ◽  
Author(s):  
V.S.N. Prasad ◽  
B. Yegnanarayana
Keyword(s):  
Potential Fields ◽  
Axes Of Symmetry

Polygonal profiles of ferritin molecules

1983 ◽  
Vol 41 ◽  
pp. 600-601
Author(s):  
William H. Massover
Keyword(s):  
Axial Ratio ◽  
X Ray Diffraction ◽  
Rhombic Dodecahedron ◽  
Apparent Contradiction ◽  
Iron Storage ◽  
X Ray ◽  
Hexagonal Shape ◽  
Axes Of Symmetry ◽  
Apparent Conflict ◽  
Iron Storage Protein

The molecular structure of the iron-storage protein, ferritin, is becoming known in ever finer detail. The 24 apoferritin subunits (MW ca. 20,000) have a 2:1 axial ratio and are polymerized with 4:3:2 symmetry to form an outer shell surrounding a variable amount of microcrystalline iron, Recent x-ray diffraction results indicate that the projected outline of the native molecule has a quasi-hexagonal shape when viewed down the 3-fold axes of symmetry, and a quasi-square shape when looking down the 4-fold axes. To date, no electron microscope study has reported observing anything other than circular profiles, which would indicate that ferritin is strictly spherical. The apparent conflict between the "hollow sphere" of electron microscopy (E.M.) and the "truncated rhombic dodecahedron" of x-ray diffraction could reflect the poorer effective resolution of E.M. coming from radiation damage, staining, drying, etc. The present study investigates the detailed shape of individual ferritin molecules in order to search for the predicted aspherical profiles and to interpret the nature of this apparent contradiction.

The Deformation Structure of the Nuclei 32S and 36Ar

2017 ◽  
Vol 13 (2) ◽  
pp. 4678-4688
Author(s):  
K. A. Kharroube
Keyword(s):  
Single Particle ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Moments Of Inertia ◽  
Deformation Structures ◽  
Particle Potential ◽  
Nilsson Model ◽  
Single Particle Potential ◽  
Axes Of Symmetry ◽  
Good Agreement

We applied two different approaches to investigate the deformation structures of the two nuclei S32 and Ar36 . In the first approach, we considered these nuclei as being deformed and have axes of symmetry. Accordingly, we calculated their moments of inertia by using the concept of the single-particle Schrödinger fluid as functions of the deformation parameter β. In this case we calculated also the electric quadrupole moments of the two nuclei by applying Nilsson model as functions of β. In the second approach, we used a strongly deformed nonaxial single-particle potential, depending on Î² and the nonaxiality parameter γ , to obtain the single-particle energies and wave functions. Accordingly, we calculated the quadrupole moments of S32 and Ar36 by filling the single-particle states corresponding to the ground- and the first excited states of these nuclei. The moments of inertia of S32 and Ar36 are then calculated by applying the nuclear superfluidity model. The obtained results are in good agreement with the corresponding experimental data.

scholarly journals Adaptive Artificial Potential Fields with Orientation Control Applied to Robotic Manipulators

2020 ◽  
Vol 53 (2) ◽  
pp. 9924-9929
Author(s):  
Caio Cristiano Barros Viturino ◽  
Ubiratan de Melo Pinto Junior ◽  
André Gustavo Scolari Conceição ◽  
Leizer Schnitman
Keyword(s):  
Robotic Manipulators ◽  
Potential Fields ◽  
Orientation Control ◽  
Artificial Potential Fields

scholarly journals General Environment Description Language

2021 ◽  
Vol 11 (2) ◽  
pp. 740
Author(s):  
Krzysztof Zatwarnicki ◽  
Waldemar Pokuta ◽  
Anna Bryniarska ◽  
Anna Zatwarnicka ◽  
Andrzej Metelski ◽  
...  
Keyword(s):  
Intelligent Systems ◽  
General Purpose ◽  
The Other ◽  
Potential Fields ◽  
General Intelligence ◽  
Language Usage ◽  
Description Language ◽  
It Systems ◽  
New Research ◽  
Future Work

Artificial intelligence has been developed since the beginning of IT systems. Today there are many AI techniques that are successfully applied. Most of the AI field is, however, concerned with the so-called “narrow AI” demonstrating intelligence only in specialized areas. There is a need to work on general AI solutions that would constitute a framework enabling the integration of already developed narrow solutions and contribute to solving general problems. In this work, we present a new language that potentially can become a base for building intelligent systems of general purpose in the future. This language is called the General Environment Description Language (GEDL). We present the motivation for our research based on the other works in the field. Furthermore, there is an overall description of the idea and basic definitions of elements of the language. We also present an example of the GEDL language usage in the JSON notation. The example shows how to store the knowledge and define the problem to be solved, and the solution to the problem itself. In the end, we present potential fields of application and future work. This article is an introduction to new research in the field of Artificial General Intelligence.

scholarly journals A robotic grasping approach with elliptical cone-based potential fields under disturbed scenes

2021 ◽  
Vol 18 (1) ◽  
pp. 172988142098573
Author(s):  
Wenjie Geng ◽  
Zhiqiang Cao ◽  
Zhonghui Li ◽  
Yingying Yu ◽  
Fengshui Jing ◽  
...  
Keyword(s):  
Principal Component ◽  
Major Axis ◽  
Target Object ◽  
Potential Fields ◽  
Single Shot ◽  
Robotic Grasping ◽  
Vertical Projection ◽  
Convex Curves ◽  
Functional Representation ◽  
Continuous Potential

Vision-based grasping plays an important role in the robot providing better services. It is still challenging under disturbed scenes, where the target object cannot be directly grasped constrained by the interferences from other objects. In this article, a robotic grasping approach with firstly moving the interference objects is proposed based on elliptical cone-based potential fields. Single-shot multibox detector (SSD) is adopted to detect objects, and considering the scene complexity, Euclidean cluster is also employed to obtain the objects without being trained by SSD. And then, we acquire the vertical projection of the point cloud for each object. Considering that different objects have different shapes with respective orientation, the vertical projection is executed along its major axis acquired by the principal component analysis. On this basis, the minimum projected envelope rectangle of each object is obtained. To construct continuous potential field functions, an elliptical-based functional representation is introduced due to the better matching degree of the ellipse with the envelope rectangle among continuous closed convex curves. Guided by the design principles, including continuity, same-eccentricity equivalence, and monotonicity, the potential fields based on elliptical cone are designed. The current interference object to be grasped generates an attractive field, whereas other objects correspond to repulsive ones, and their resultant field is used to solve the best placement of the current interference object. The effectiveness of the proposed approach is verified by experiments.

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