Modeling the Systematic Uncertainty of Photogrammetric Tracking of Human Motion

1997 ◽  
Vol 119 (2) ◽  
pp. 358-361 ◽  
Author(s):  
S. B. Bortolami ◽  
P. O. Riley ◽  
D. E. Krebs
Keyword(s):  
Uncertainty Modeling ◽  
Human Locomotion ◽  
Human Motion ◽  
Tracking Data ◽  
Total Uncertainty ◽  
Rotation Matrices ◽  
Self Consistent ◽  
Consistent Manner ◽  
Set Up ◽  
Derivatives Of

We address bias errors of photogrammetric tracking of four SELSPOT-II® cameras using active marker photogrammetry in a 2 m × 2 m × 2 m viewing volume for human locomotion measurements. We present uncertainty modeling regarding the first stage of equipment set up, which provides the camera frame to global frame rotation matrices and the distances among cameras. We also characterize the uncertainty due to the camera distortions of the bare system as compared to published performances achieved with a camera correction procedure. The particular approach is to qualify performances of photogrammetric tracking during routine operation and to identify the nature and magnitude of the uncertainty due to equipment set up and camera distortions as part of the total uncertainty in a self-consistent manner. We found that uncertainty of the camera frame to global frame rotation matrices produced rotation of the image and uncorrected camera hardware uncertainty produced dilatation or compression of the image twice the magnitude of that seen with camera correction. However, camera resolution remains as an equally important factor limiting the accuracy of photogrammetric tracking that can not be easily reduced numerically. In conclusion, the analysis elucidates how uncertainty propagates to numerical derivatives of the tracking data and prepares the groundwork for future development.

scholarly journals Magnetohydrodynamics in a cylindrical shearing box

2019 ◽  
Vol 71 (5) ◽  
Author(s):  
Takeru K Suzuki ◽  
Tetsuo Taki ◽  
Scott S Suriano
Keyword(s):  
Mhd Equations ◽  
Radial Dependence ◽  
Mhd Turbulence ◽  
Magnetorotational Instability ◽  
Mhd Simulations ◽  
Self Consistent ◽  
Consistent Manner ◽  
Set Up ◽  
Isothermal Equation ◽  
Physical Quantities

ABSTRACT We develop a framework for magnetohydrodynamical (MHD) simulations in a local cylindrical shearing box by extending the formulation of the Cartesian shearing box. We construct shearing-periodic conditions at the radial boundaries of a simulation box from the conservation relations of the basic MHD equations, taking into account the explicit radial dependence of physical quantities. We demonstrate quasi-steady mass accretion, which cannot be handled by the standard Cartesian shearing box model, with an ideal MHD simulation in a vertically unstratified cylindrical shearing box for up to 200 rotations. In this demonstrative run we set up (i) net vertical magnetic flux, (ii) a locally isothermal equation of state, and (iii) a sub-Keplerian equilibrium rotation, whereas the sound velocity and the initial Alfvén velocity have the same radial dependence as that of the Keplerian velocity. Inward mass accretion is induced to balance the outward angular momentum flux of the MHD turbulence triggered by the magnetorotational instability in a self-consistent manner. We discuss detailed physical properties of the saturated magnetic field, in comparison to the results of a Cartesian shearing box simulation.

scholarly journals Developing a BIM-Based MUVR Treadmill System for Architectural Design Review and Collaboration

2021 ◽  
Vol 11 (15) ◽  
pp. 6881
Author(s):  
Calvin Chung Wai Keung ◽  
Jung In Kim ◽  
Qiao Min Ong
Keyword(s):  
Architectural Design ◽  
Human Locomotion ◽  
Virtual Space ◽  
Design Stage ◽  
Design Review ◽  
Team Members ◽  
Physical Constraints ◽  
Simulated Environment ◽  
Set Up ◽  
High Level

Virtual reality (VR) is quickly becoming the medium of choice for various architecture, engineering, and construction applications, such as design visualization, construction planning, and safety training. In particular, this technology offers an immersive experience to enhance the way architects review their design with team members. Traditionally, VR has used a desktop PC or workstation setup inside a room, yielding the risk of two users bump into each other while using multiuser VR (MUVR) applications. MUVR offers shared experiences that disrupt the conventional single-user VR setup, where multiple users can communicate and interact in the same virtual space, providing more realistic scenarios for architects in the design stage. However, this shared virtual environment introduces challenges regarding limited human locomotion and interactions, due to physical constraints of normal room spaces. This study thus presented a system framework that integrates MUVR applications into omnidirectional treadmills. The treadmills allow users an immersive walking experience in the simulated environment, without space constraints or hurt potentialities. A prototype was set up and tested in several scenarios by practitioners and students. The validated MUVR treadmill system aims to promote high-level immersion in architectural design review and collaboration.

scholarly journals Entropic measure unveils country competitiveness and product specialization in the World trade web

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Gianluca Teza ◽  
Michele Caraglio ◽  
Attilio L. Stella
Keyword(s):  
Iterative Scheme ◽  
Entropy Function ◽  
Bipartite Networks ◽  
Complexity Measures ◽  
Wide Range ◽  
Self Consistent ◽  
Set Up ◽  
Technical Features ◽  
Country Competitiveness ◽  
Entropic Measure

AbstractWe show how the Shannon entropy function can be used as a basis to set up complexity measures weighting the economic efficiency of countries and the specialization of products beyond bare diversification. This entropy function guarantees the existence of a fixed point which is rapidly reached by an iterative scheme converging to our self-consistent measures. Our approach naturally allows to decompose into inter-sectorial and intra-sectorial contributions the country competitivity measure if products are partitioned into larger categories. Besides outlining the technical features and advantages of the method, we describe a wide range of results arising from the analysis of the obtained rankings and we benchmark these observations against those established with other economical parameters. These comparisons allow to partition countries and products into various main typologies, with well-revealed characterizing features. Our methods have wide applicability to general problems of ranking in bipartite networks.

Two in one: bifunctional derivatives of trolox acting as antimalarial and antioxidant agents

2020 ◽  
Vol 12 (20) ◽  
pp. 1845-1854
Author(s):  
Florence Souard ◽  
Edwige Nicolle ◽  
Delphine Cressend ◽  
Alexis Valentin ◽  
Ahcène Boumendjel
Keyword(s):  
Antioxidant Activity ◽  
Ascorbic Acid ◽  
In Vivo Studies ◽  
Chemical Libraries ◽  
Falciparum Strain ◽  
Antioxidant Agents ◽  
One Step ◽  
Set Up ◽  
Derivatives Of

Background: The aim of the present work was to set-up compounds that are able to act simultaneously as antimalarial and antioxidants. Trolox, a known antioxidant was chosen as a core structure to ensure the antioxidant activity and contribute to antiplasmodial effect. Results: Ten compounds were prepared in one step and evaluated on chloroquino-sensitive (3D7) and chloroquino-resistant (FcB1) strains of Plasmodium falciparum. The most active compound (3d) shows antiplasmodial activity in the range of chloroquine against chloroquino-sensitive and chloroquino-resistant P. falciparum strain. The antioxidant activity of (3d) was conducted through four tests and was found to be more potent than trolox itself and L-ascorbic acid. Conclusion: Compound (3d) can be considered as an excellent lead molecule for further in vivo studies. This study paves the way for building large chemical libraries to be investigated in the field of malaria.

scholarly journals SteadEye-Head—Improving MARG-Sensor Based Head Orientation Measurements Through Eye Tracking Data

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2759 ◽  
Author(s):  
Lukas Wöhle ◽  
Marion Gebhard
Keyword(s):  
Data Fusion ◽  
Eye Tracking ◽  
Medical Diagnostics ◽  
Human Motion ◽  
Rehabilitation Robotics ◽  
Sensor Data ◽  
Head Orientation ◽  
Human Motion Analysis ◽  
Tracking Data ◽  
Sensor Data Fusion

This paper presents the use of eye tracking data in Magnetic AngularRate Gravity (MARG)-sensor based head orientation estimation. The approach presented here can be deployed in any motion measurement that includes MARG and eye tracking sensors (e.g., rehabilitation robotics or medical diagnostics). The challenge in these mostly indoor applications is the presence of magnetic field disturbances at the location of the MARG-sensor. In this work, eye tracking data (visual fixations) are used to enable zero orientation change updates in the MARG-sensor data fusion chain. The approach is based on a MARG-sensor data fusion filter, an online visual fixation detection algorithm as well as a dynamic angular rate threshold estimation for low latency and adaptive head motion noise parameterization. In this work we use an adaptation of Madgwicks gradient descent filter for MARG-sensor data fusion, but the approach could be used with any other data fusion process. The presented approach does not rely on additional stationary or local environmental references and is therefore self-contained. The proposed system is benchmarked against a Qualisys motion capture system, a gold standard in human motion analysis, showing improved heading accuracy for the MARG-sensor data fusion up to a factor of 0.5 while magnetic disturbance is present.

scholarly journals Direct simulation on nonlinear thermokinetic phenomena due to induced-charge electroosmosis

2018 ◽  
Vol 855 ◽  
pp. 736-769 ◽  
Author(s):  
Hideyuki Sugioka
Keyword(s):  
Electric Field ◽  
Vortex Flow ◽  
Direct Simulation ◽  
General Phenomenon ◽  
Dielectric Particles ◽  
Self Consistent ◽  
Physics Simulation ◽  
Normal Diffusion ◽  
Consistent Manner ◽  
The Stokes Equation

Previously, we proposed a novel mechanism to produce a nonlinear thermokinetic phenomenon (NTKP) around a metal cylinder in an electrolyte on the basis of analytical discussion. In this study, by using a non-steady direct multi-physics simulation technique based on the Stokes equation coupled with the electroosmotic equation that considers normal diffusion, electrophoresis and thermal diffusion, we directly verify the NTKP and show that the original driving force is the excess ions pressed on the particle by the thermokinetic force and that the NTKP vortex flow around the particle is generated by the interaction between the excess ion and the electric field that is made by the excess ions and/or the Seebeck electric field due to the blocking boundary condition on the wall. Namely, two types of NTKP exist and they are explained in a self-consistent manner by our new theory. In addition, through the discussion of a dielectric particle, we show that the NTKP is a general phenomenon that can be found in both metal and dielectric particles. We believe that our findings provide a new unified viewpoint to understand complex thermokinetic phenomena near metal and dielectric particles.

RESONANT THz EMISSION IN A GRATING-COUPLED QUANTUM WELL DRIVEN BY DC CURRENT

2003 ◽  
Vol 17 (31n32) ◽  
pp. 6067-6071 ◽  
Author(s):  
S. K. HONG ◽  
I. V. SMETANIN ◽  
H. HAN
Keyword(s):  
Quantum Well ◽  
Emission Spectra ◽  
Two Dimensional ◽  
Purcell Effect ◽  
Resonant Enhancement ◽  
Self Consistent ◽  
Consistent Manner ◽  
Dc Current ◽  
Coupled Quantum Well

THz emission spectra from a grating-coupled two-dimensional plasmon system driven by DC current are calculated in a self-consistent manner. The emission peaks show strong resonant enhancement due to Smith–Purcell effect.

Chiral effects in the scattering of electrons by molecules

1996 ◽  
Vol 74 (11-12) ◽  
pp. 920-924 ◽  
Author(s):  
D. G. Thompson
Keyword(s):  
Physical Mechanism ◽  
Closed Shell ◽  
Spin Orbit ◽  
Polarized Electrons ◽  
Invariance Properties ◽  
Inversion Time ◽  
Consistent Manner ◽  
Chiral Effects ◽  
Set Up ◽  
Considerable Discussion

There are a number of scattering phenomena that depend on the "handedness" of the scattering system. In this paper we concentrate on the elastic scattering of polarized electrons by closed-shell molecules and consider mainly the property of electron optic dichroism. The effects can be fully analysed using the general invariance properties of the scattering matrix under spatial inversion, time reversal, and rotations. However, there is still considerable discussion about the physical mechanism causing the effects. Among the models proposed are two involving the spin–orbit interaction; in one the bound orbitals are perturbed, and in the other the incident electron. In this paper we show how these two approaches can be combined in a unified treatment. We set up the scattering equation including exchange and spin–orbit in a consistent manner and identify which terms contribute to the chiral effects.

RENORMALIZATION AND BOLTZMANN EQUATIONS IN THERMAL QUANTUM FIELD THEORY

1995 ◽  
Vol 10 (11) ◽  
pp. 1693-1700 ◽  
Author(s):  
H. CHU ◽  
H. UMEZAWA
Keyword(s):  
Boltzmann Equation ◽  
Renormalization Scheme ◽  
Quantum Field Theories ◽  
Quantum Field ◽  
Boltzmann Equations ◽  
Self Energy ◽  
Spatially Inhomogeneous ◽  
Thermo Field Dynamics ◽  
Self Consistent ◽  
Consistent Manner

The renormalization scheme in nonequilibrium thermal quantum field theories is reexamined. Instead of the self-energy diagonalization scheme, we propose to diagonalize Green’s function at equal time. This eliminates the problem of on-shell definition related to time-dependent energies and spatially inhomogeneous situations, and yields a Boltzmann equation that contains memory effect. The new diagonalization scheme and the derivation of the Boltzmann equation from it can be applied to any thermal situation. It allows the treatment of a nonequilibrium problem beyond perturbational calculations in a self-consistent manner. The results are applicable to both thermo field dynamics and the closed time path formalism.

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