A geometrical property of POV-measures and systems of covariance

1982 ◽  
pp. 207-228 ◽  
Author(s):  
S. Twareque Ali
Keyword(s):  
Geometrical Property ◽  
Pov Measures ◽  
Systems Of Covariance

scholarly journals The non-Hermitian geometrical property of 1D Lieb lattice under Majorana’s stellar representation

2020 ◽  
Vol 32 (42) ◽  
pp. 425402
Author(s):  
Xingran Xu ◽  
Haodi Liu ◽  
Zhidong Zhang ◽  
Zhaoxin Liang
Keyword(s):  
Geometrical Property ◽  
Lieb Lattice

Transition mechanism design of a hybrid wheel-track-leg based on foldable rims

2019 ◽  
Vol 233 (13) ◽  
pp. 4788-4801 ◽  
Author(s):  
Faliang Zhou ◽  
Xiaojun Xu ◽  
Haijun Xu ◽  
Teng’an Zou ◽  
Lei Zhang
Keyword(s):  
Driving Force ◽  
Geometrical Property ◽  
Screw Theory ◽  
Transition Process ◽  
Performance Comparison ◽  
Dynamic Simulations ◽  
Compact Structure ◽  
Transition Mechanism ◽  
Wheel Rim ◽  
Wheel Track

Hybrid mobile robots with multiple locomotion modes are getting more and more popular in search and rescue (SAR) and explosive object disposal (EOD) missions because of their good terrain adaptability. Present researchers devote themselves to develop efficient and reliable transition method between different locomotion modes to make the hybrid robot more compact and flexible. In this paper, we present a novel transition mechanism for a hybrid wheel-track based on foldable rims. The wheel rim is cut into four segments so that it is foldable. And the transition between wheel and track is achieved by the folding or unfolding of the foldable rim. According to its geometrical property during the transition process, a single-freedom supporting spoke is proposed to drive the foldable rim’s transformation. We analyze the length and angle varying principles of the supporting spoke by utilizing the kinematic mode based on screw theory. According to above results, five different kinds of transition mechanism of the supporting spoke is designed, performance comparison among which is conducted by dynamic simulations. Two of the five candidate transition mechanisms are picked up for their smaller driving force requirements. Their 3D printing prototypes are also fabricated and experiments show that the hybrid wheel-track can switch between wheel and track successfully. Compared to most hybrid robots which have separate wheels, tracks and legs, this transition mechanism makes the robot own both compact structure and multimodal locomotion.

scholarly journals EO Sensor Planning for UAV Engineering Reconnaissance Based on NIIRS and GIQE

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Jingbo Bai ◽  
Yangyang Sun ◽  
Liang Chen ◽  
Yufang Feng ◽  
Jianyong Liu
Keyword(s):  
Image Quality ◽  
Unmanned Aerial Vehicles ◽  
Rating Scale ◽  
Geometrical Property ◽  
Quantitative Relationship ◽  
Flight Altitude ◽  
Sensor Planning ◽  
Visible Image ◽  
Sensor Performance ◽  
Information Interpretation

When unmanned aerial vehicles (UAVs) support the Corps of Engineers in reconnaissance operations, in order to gather visible image information that should meet the mission’s need, we grouped the engineering reconnaissance information interpretation tasks into 10 levels by using the National Imagery Interpretability Rating Scale (NIIRS). The quantitative relationship between the engineering targets, sensor performance, and flight altitude was established through the general image quality equation (GIQE) and the geometrical property of the ground sampled distance (GSD). Through some simulations, the influence of variable factors of the EO sensor imaging quality was analyzed, and the imaging height of the sensor for an engineering reconnaissance scenario was calculated. The results showed that this study could solve the problem of poor image quality caused by the flight altitude not meeting the mission requirements.

Study on Heat Distribution of Pans

2013 ◽  
Vol 821-822 ◽  
pp. 1398-1401
Author(s):  
Wang Yong Lv ◽  
Can Guo ◽  
Hui Qi Wang ◽  
Yun Ling
Keyword(s):  
Computer Simulation ◽  
Geometrical Property ◽  
Regular Polygon ◽  
Outer Edge ◽  
Distribution Model ◽  
Heat Distribution ◽  
Property A ◽  
Thermal Distribution ◽  
Different Shapes

During baking, rectangular pans often overcook the product and round pans can't make full use of the space of the oven. In this paper, two models are build to discuss the heat distribution and uniformity of different shapes pans. Initially build the heat uniformity Model. Through the analysis of the heat distribution and geometrical property, a formula is given to calculate the uniformity of regular polygon. In order to describe the heat uniformity of all kind of shape, the thermal distribution model is build to discuss the heat distribution of the bottom of different pans. By computer simulation, the temperature at the corners of the rectangular pan is the highest and the temperature across the outer edge of the round pan is even, which is consistent with reality.

Who Is Afraid of POV Measures? Unified Approach to Quantum Phase Observables

1995 ◽  
Vol 237 (1) ◽  
pp. 1-11 ◽  
Author(s):  
P. Busch ◽  
M. Grabowski ◽  
P.J. Lahti
Keyword(s):  
Quantum Phase ◽  
Unified Approach ◽  
Pov Measures
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