Self-gravitating three-dimensional solitons in nonlinear scale-invariant electrodynamics

1996 ◽  
Vol 35 (7) ◽  
pp. 1493-1502 ◽  
Author(s):  
I. G. Chugunov ◽  
Yu. P. Rybakov ◽  
G. N. Shikin
Keyword(s):  
Three Dimensional ◽  
Scale Invariant ◽  
Nonlinear Scale

scholarly journals Real-time FPGA-based implementation of the AKAZE algorithm with nonlinear scale space generation using image partitioning

2021 ◽  
Author(s):  
Parastoo Soleimani ◽  
David W. Capson ◽  
Kin Fun Li
Keyword(s):  
Real Time ◽  
Memory Management ◽  
Scale Space ◽  
Image Resolution ◽  
Hardware Architecture ◽  
Frame Rate ◽  
Time Sharing ◽  
Scale Invariant ◽  
Nonlinear Scale Space ◽  
Nonlinear Scale

AbstractThe first step in a scale invariant image matching system is scale space generation. Nonlinear scale space generation algorithms such as AKAZE, reduce noise and distortion in different scales while retaining the borders and key-points of the image. An FPGA-based hardware architecture for AKAZE nonlinear scale space generation is proposed to speed up this algorithm for real-time applications. The three contributions of this work are (1) mapping the two passes of the AKAZE algorithm onto a hardware architecture that realizes parallel processing of multiple sections, (2) multi-scale line buffers which can be used for different scales, and (3) a time-sharing mechanism in the memory management unit to process multiple sections of the image in parallel. We propose a time-sharing mechanism for memory management to prevent artifacts as a result of separating the process of image partitioning. We also use approximations in the algorithm to make hardware implementation more efficient while maintaining the repeatability of the detection. A frame rate of 304 frames per second for a $$1280 \times 768$$ 1280 × 768 image resolution is achieved which is favorably faster in comparison with other work.

scholarly journals Collective forces of tumor spheroids in three-dimensional biopolymer networks

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christoph Mark ◽  
Thomas J Grundy ◽  
Pamela L Strissel ◽  
David Böhringer ◽  
Nadine Grummel ◽  
...  
Keyword(s):  
Single Cells ◽  
Three Dimensional ◽  
Traction Force ◽  
Tumor Spheroids ◽  
Scale Invariant ◽  
Tissue Samples ◽  
Force Microscopy ◽  
Surrounding Matrix ◽  
Highly Nonlinear ◽  
Contractile Forces

We describe a method for quantifying the contractile forces that tumor spheroids collectively exert on highly nonlinear three-dimensional collagen networks. While three-dimensional traction force microscopy for single cells in a nonlinear matrix is computationally complex due to the variable cell shape, here we exploit the spherical symmetry of tumor spheroids to derive a scale-invariant relationship between spheroid contractility and the surrounding matrix deformations. This relationship allows us to directly translate the magnitude of matrix deformations to the total contractility of arbitrarily sized spheroids. We show that our method is accurate up to strains of 50% and remains valid even for irregularly shaped tissue samples when considering only the deformations in the far field. Finally, we demonstrate that collective forces of tumor spheroids reflect the contractility of individual cells for up to 1 hr after seeding, while collective forces on longer timescales are guided by mechanical feedback from the extracellular matrix.

Fractal analysis of a new generation of HVOF sprayed coatings based on optical surface metrology

2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Yibo Zou ◽  
Markus Kästner ◽  
Eduard Reithmeier
Keyword(s):  
Fractal Dimension ◽  
Fractal Analysis ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Confocal Laser Scanning Microscope ◽  
Confocal Laser ◽  
Surface Metrology ◽  
Roughness Parameters ◽  
Scale Invariant ◽  
Sprayed Coatings

AbstractIn this article, fractal analysis combined with roughness measurement is proposed to characterize the new generations of HVOF sprayed coatings' surface textures. Two-dimensional and three-dimensional box counting algorithms are introduced to determine the fractal dimension, which is considered as a scale-invariant parameter and is able to describe chaos and complexity of the surface. For surface roughness metrology, a confocal laser scanning microscope with different lenses is used to acquire the areal topography, providing a sequence of height maps with different image resolutions. Typical areal roughness parameters are assessed based on the international standard ISO-25178. The results show that the fractal dimension is a powerful tool to depict the nature of the surface texture of the investigated coatings. Moreover, it is found that the traditional amplitude roughness parameters depend strongly on the range of the measurement field as well as the datasets' resolution, whereas the fractal dimension is rather invariant to the scales of the measured datasets. Finally, the correlation between the fractal dimension and roughness parameters is given at the end of this paper.

scholarly journals HIDDEN SCALE IN QUANTUM MECHANICS

2009 ◽  
Vol 24 (27) ◽  
pp. 2203-2211 ◽  
Author(s):  
PULAK RANJAN GIRI
Keyword(s):  
Wave Packet ◽  
Quantum Particle ◽  
Dimensional Space ◽  
Free Particle ◽  
Three Dimensional ◽  
Particle Systems ◽  
Quantum Mechanical ◽  
Scale Invariant ◽  
Mechanical Models ◽  
Three Dimensional Space

We show that the intriguing localization of a free particle wave-packet is possible due to a hidden scale present in the system. Self-adjoint extensions (SAE) is responsible for introducing this scale in quantum mechanical models through the nontrivial boundary conditions. We discuss a couple of classically scale invariant free particle systems to illustrate the issue. In this context it has been shown that a free quantum particle moving on a full line may have localized wave-packet around the origin. As a generalization, it has also been shown that particles moving on a portion of a plane or on a portion of a three-dimensional space can have unusual localized wave-packet.

scholarly journals SHORT-TIME EXISTENCE FOR SCALE-INVARIANT HAMILTONIAN WAVES

2006 ◽  
Vol 03 (02) ◽  
pp. 247-267 ◽  
Author(s):  
JOHN K. HUNTER
Keyword(s):  
Rayleigh Waves ◽  
Evolution Equations ◽  
Hyperbolic Surface ◽  
Smooth Solutions ◽  
Scale Invariant ◽  
Weakly Nonlinear ◽  
Hamiltonian Evolution ◽  
Short Time ◽  
Nonlinear Scale ◽  
Time Existence

We prove short-time existence of smooth solutions for a class of nonlinear, and in general spatially nonlocal, Hamiltonian evolution equations that describe the self-interaction of weakly nonlinear scale-invariant waves. These equations include ones that describe weakly nonlinear hyperbolic surface waves, such as nonlinear Rayleigh waves in elasticity.

scholarly journals Scale-Invariant Drain Current in Nano-FETs

2010 ◽  
Vol 10 ◽  
pp. 49-61 ◽  
Author(s):  
Ulrich Wulf ◽  
Hans Richter
Keyword(s):  
Low Temperatures ◽  
Transport Model ◽  
Characteristic Length ◽  
Three Dimensional ◽  
Drain Current ◽  
Drain Voltage ◽  
Scale Invariant ◽  
Electron Channel ◽  
Long Channel ◽  
Strong Barrier

Starting from a three-dimensional transport model in the Landauer-Buttiker formalism we derive a scale-invariant expression for the drain current in a nano-transistor. Apart from dimensionless external parameters representing temperature, gate-, and drain voltage the normalized drain current depends on two dimensionless transistor parameters which are the characteristic length l and -width w of the electron channel. The latter quantities are the physical length and -width of the channel in units of the scaling length = ~(2mF )1=2. Here F is the Fermi energy in the source contact and m is the eective mass in the electron channel. In the limit of wide transistors and low temperatures we evaluate the scale-invariant IDVD characteristics as a function of the characteristic length. In the strong barrier regime, i. e. for l & 20 long-channel behavior is found. At weaker barriers source-drain tunneling leads to increasingly signicant deviations from the long-channel behavior. We compare with experimental results.

Study on Integrated Setup System with Computer Vision for Breast Cancer Radiotherapy

2011 ◽  
Vol 328-330 ◽  
pp. 2333-2336
Author(s):  
Lei Tong ◽  
Chao Hua Zhu ◽  
Zhi Qiang He
Keyword(s):  
Breast Cancer ◽  
Three Dimensional ◽  
Setup Error ◽  
Multiple Characteristic ◽  
Scale Invariant ◽  
Verification Method ◽  
Searching Strategy ◽  
Breast Cancer Radiotherapy ◽  
Time Calculation ◽  
Fractional Irradiation

Purpose: To discuss a setup verification method based on computer stereo vision for the repeat setup in breast cancer fractional irradiation. Methods and Materials: A photogrammetric system is composed of two cameras and one computer. First, multiple characteristic markers’ coordinates are gotten by the two cameras, then the three-dimensional coordinates of the markers are calculated according to the basic principle of binocular calculated, which can construct breast and chest surface stereo features shape, thus the setup error can judge and correct before radiation therapy. At the tracking process, we use SITF (Scale Invariant Feature Transform) as the registration algorithm, which has strong robustness and accurate matching performance, meanwhile, dynamic choice matching image and local searching strategy are used in the process of calculation and mergence in order to make the target image matching more precisely. Results: Experimental results show that in breast cancer fractional irradiation, the system can accurately display setup error and can achieve real-time calculation. Conclusion: The proposed method can reduce setup error in breast cancer fractional irradiation, and has good stability and high precision.

scholarly journals MicroCT analysis of connectivity in porous structures: optimizing data acquisition and analytical methods in the context of tissue engineering

2020 ◽  
Vol 17 (165) ◽  
pp. 20190833
Author(s):  
Malavika Nair ◽  
Jennifer H. Shepherd ◽  
Serena M. Best ◽  
Ruth E. Cameron
Keyword(s):  
Tissue Engineering ◽  
Analytical Methods ◽  
Large Scale ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Data Capture ◽  
Pixel Size ◽  
Scale Invariant ◽  
Structural Anisotropy

Micro-computed X-ray tomography (MicroCT) is one of the most powerful techniques available for the three-dimensional characterization of complex multi-phase or porous microarchitectures. The imaging and analysis of porous networks are of particular interest in tissue engineering due to the ability to predict various large-scale cellular phenomena through the micro-scale characterization of the structure. However, optimizing the parameters for MicroCT data capture and analyses requires a careful balance of feature resolution and computational constraints while ensuring that a structurally representative section is imaged and analysed. In this work, artificial datasets were used to evaluate the validity of current analytical methods by considering the effect of noise and pixel size arising from the data capture, and intrinsic structural anisotropy and heterogeneity. A novel ‘segmented percolation method’ was developed to exclude the effect of anomalous, non-representative features within the datasets, allowing for scale-invariant structural parameters to be obtained consistently and without manual intervention for the first time. Finally, an in-depth assessment of the imaging and analytical procedures are presented by considering percolation events such as micro-particle filtration and cell sieving within the context of tissue engineering. Along with the novel guidelines established for general pixel size selection for MicroCT, we also report our determination of 3 μm as the definitive pixel size for use in analysing connectivity for tissue engineering applications.

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