Space, Form and Optical Deformations

1985 ◽  
pp. 31-58 ◽  
Author(s):  
Jan J. Koenderink
Keyword(s):  
Space Form

Triharmonic Riemannian submersions from 3-dimensional space forms

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Tomoya Miura ◽  
Shun Maeta
Keyword(s):  
Existence Theorem ◽  
Space Form ◽  
Dimensional Space ◽  
Riemannian Submersion ◽  
Partial Answer ◽  
Riemannian Submersions ◽  
Space Forms ◽  
3 Dimensional

Abstract We show that any triharmonic Riemannian submersion from a 3-dimensional space form into a surface is harmonic. This is an affirmative partial answer to the submersion version of the generalized Chen conjecture. Moreover, a non-existence theorem for f -biharmonic Riemannian submersions is also presented.

Structure Model and Developing Rules of Space Form Evolution of Xi'an High-Tech Industries Development Zone

2013 ◽  
Vol 357-360 ◽  
pp. 1953-1957 ◽  
Author(s):  
Zhe Cui ◽  
Yuan Zhang
Keyword(s):  
Structural Change ◽  
Geographic Distribution ◽  
High Speed ◽  
Space Form ◽  
High Tech ◽  
Structure Model ◽  
Spatial Form ◽  
Development Zone ◽  
Initial Development ◽  
New Town

The paper analyzed development process of Xian high-tech industries development Zone. Summarizes the structure model of space form evolution of Xian high-tech zone as six stages: Growing point gatheringDispersion; Growth axis formingCircle domain; Point axis stretchExtension; Leaping growthNew points; Introverted fillingInflation; Circle differentiationFusion. At last, combined with the process of cell division theory, the paper puts forward developing rules of spatial form evolution of Xian high-tech zone as the process of cell fission of four stages: Space structural change of the geographic distribution in initial development periodIndustry zone of single function; Space structural change of the geographic distribution in accelerated development periodComprehensive industrial zone of specialization accumulated; Space structural change of the geographic distribution in high speed development periodGroup service center of complex new town; Space structural change of the geographic distribution in the futureSub-center of city.

scholarly journals CR-warped product submanifolds of a generalized complex space form

2017 ◽  
Vol 4 (1) ◽  
pp. 1306153
Author(s):  
Meraj Ali Khan ◽  
Amira A. Ishan ◽  
Hari M. Srivastava
Keyword(s):  
Warped Product ◽  
Complex Space ◽  
Space Form ◽  
Complex Space Form ◽  
Generalized Complex

Franciscan Books and their Readers

2022 ◽  
Author(s):  
René Hernández
Keyword(s):  
Space Form ◽  
Northern Italy ◽  
Ideal Space ◽  
Skilled Readers ◽  
Personal Library ◽  
Key Aspects ◽  
Cultural Agency ◽  
First Time ◽  
The Ideal

The book explores the manuscripts written, read, and studied by Franciscan friars from the thirteenth to the fifteenth centuries in Northern Italy, and specifically Padua, assessing four key aspects: ideal, space, form and readership. The ideal is studied through the regulations that determined what manuscripts should aim for. Space refers to the development and role of Franciscan libraries. The form is revealed by the assessment of the physical configuration of a set of representative manuscripts read, written, and manufactured by the friars. Finally, the study of the readership shows how Franciscans were skilled readers who employed certain forms of the manuscript as a portable, personal library, and as a tool for learning and pastoral care. By comparing the book collections of Padua’s reformed and unreformed medieval Franciscan libraries for the first time, this study reveals new features of the ground-breaking cultural agency of medieval friars.

TOPOLOGY OF POLITICAL COMMUNICATIONS IN SPACE NETWORK SOCIETY: METHODOLOGY OF ANALYSIS AND PRACTICE

2021 ◽  
Vol 16 (4) ◽  
pp. 58-70
Author(s):  
O.G. SHCHENINA ◽  
Keyword(s):  
System Approach ◽  
Space Form ◽  
Interdisciplinary Approach ◽  
Network Society ◽  
The Political ◽  
Space Network ◽  
Political Communications ◽  
Basic Concepts ◽  
Methodological Approaches ◽  
Analysis System

The purpose of the article is to study the topology of political communications in the conditions of the formation of a network society. The topological context of the study of political communications involves an appeal to the basic concepts of topology (space, form, time), as well as the phenomena of morphogenesis and homeomorphism. The main content of the article includes the study of a number of theoretical and methodological approaches of political topology in the communicative and communication perspectives. The author is based on the application of methods of content analysis, discourse analysis, system approach, network approach to identify topological aspects of political communications.As a result, the analysis carried out by the author showed that significant changes in the political space are taking place in the network society on the basis of technological and humanitarian innovations (including under the influence of informatization, networking, digitalization), as well as forms and practices of political communications are being transformed. An interdisciplinary approach to the analysis of political communications allows us to expand the range of their research.

Design and Experimental Validation of a LQG Control System for the Stabilization of a 2DOF Commercial Gimbal Using Physical Modelling Techniques

2020 ◽  
Author(s):  
Julián Andres Gómez Gómez ◽  
Camilo E. Moncada Guayazán ◽  
Sebastián Roa Prada ◽  
Hernando Gonzalez Acevedo
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
State Space ◽  
Transient Response ◽  
Space Form ◽  
Angular Position ◽  
Physical Modelling ◽  
Motor Shaft ◽  
Brushless Dc ◽  
The Mathematical Model

Abstract Gimbals are mechatronic systems well known for their use in the stabilization of cameras which are under the effect of sudden movements. Gimbals help keeping cameras at previously defined fixed orientations, so that the captured images have the highest quality. This paper focuses on the design of a Linear Quadratic Gaussian, LQG, controller, based on the physical modeling of a commercial Gimbal with two degrees of freedom (2DOF), which is used for first-person applications in unmanned aerial vehicle (UAV). This approach is proposed to make a more realistic representation of the system under study, since it guarantees high accuracy in the simulation of the dynamic response, as compared to the prediction of the mathematical model of the same system. The development of the model starts by sectioning the Gimbal into a series of interconnected links. Subsequently, a fixed reference system is assigned to each link body and the corresponding homogeneous transformation matrices are established, which will allow the calculation of the orientation of each link and the displacement of their centers of mass. Once the total kinetic and potential energy of the mechanical components are obtained, Lagrange’s method is utilized to establish the mathematical model of the mechanical structure of the Gimbal. The equations of motion of the system are then expressed in state space form, with two inputs, two outputs and four states, where the inputs are the torques produced by each one of the motors, the outputs are the orientation of the first two links, and the states are the aforementioned orientations along with their time derivatives. The state space model was implemented in MATLAB’s Simulink environment to compare its prediction of the transient response with the prediction obtained with the representation of the same system using MATLAB’s SimMechanics physical modelling interface. The mathematical model of each one of the three-phase Brushless DC motors is also expressed in state space form, where the three inputs of each motor model are the voltages of the corresponding motor phases, its two outputs are the angular position and angular velocity, and its four states are the currents in two of the phases, the orientation of the motor shaft and its rate of change. This model is experimentally validated by performing a switching sequence in both the simulation model and the physical system and observing that the transient response of the angular position of the motor shaft is in accordance with the theoretical model. The control system design process starts with the interconnection of the models of the mechanical components and the models of the Brushless DC Motor, using their corresponding state space representations. The resulting model features six inputs, two outputs and eight states. The inputs are the voltages in each phase of the two motors in the Gimbal, the outputs are the angular positions of the first two links, and the states are the currents in two of the phases for each motor and the orientations of the first two links, along with their corresponding time derivatives. An optimal LQG control system is designed using MATLAB’s dlqr and Kalman functions, which calculate the gains for the control system and the gains for the states estimated by the observer. The external excitation in each of the phases is carried out by pulse width modulation. Finally, the transient response of the overall system is evaluated for different reference points. The simulation results show very good agreement with the experimental measurements.

Geometry of special curves and surfaces in 3-space form

2019 ◽  
Vol 136 ◽  
pp. 31-38 ◽  
Author(s):  
Jie Huang ◽  
Liang Chen ◽  
Shyuichi Izumiya ◽  
Donghe Pei
Keyword(s):  
Space Form ◽  
Curves And Surfaces
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