Definition and Framework for Contagion and Divergence Effect Modeling

2016 ◽  
Author(s):  
Piotr Jaworski
Keyword(s):  
Divergence Effect

scholarly journals Modal coupling and crosstalk due to turbulence and divergence on free space THz links using multiple orbital angular momentum beams

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhe Zhao ◽  
Runzhou Zhang ◽  
Hao Song ◽  
Kai Pang ◽  
Ahmed Almaiman ◽  
...  
Keyword(s):  
Angular Momentum ◽  
Atmospheric Turbulence ◽  
Channel Capacity ◽  
Orbital Angular Momentum ◽  
Beam Waist ◽  
Modal Coupling ◽  
Divergence Effect ◽  
Power Leakage ◽  
Calm Weather ◽  
Bad Weather

AbstractOrbital-angular-momentum (OAM) multiplexing has been utilized to increase the channel capacity in both millimeter-wave and optical domains. Terahertz (THz) wireless communication is attracting increasing attention due to its broadband spectral resources. Thus, it might be valuable to explore the system performance of THz OAM links to further increase the channel capacity. In this paper, we study through simulations the fundamental system-degrading effects when using multiple OAM beams in THz communications links under atmospheric turbulence. We simulate and analyze the effects of divergence, turbulence, limited-size aperture, and misalignment on the signal power and crosstalk of THz OAM links. We find through simulations that the system-degrading effects are different in two scenarios with atmosphere turbulence: (a) when we consider the same strength of phasefront distortion, faster divergence (i.e., lower frequency; smaller beam waist) leads to higher power leakage from the transmitted mode to neighbouring modes; and (b) however, when we consider the same atmospheric turbulence, the divergence effect tends to affect the power leakage much less, and the power leakage increases as the frequency, beam waist, or OAM order increases. Simulation results show that: (i) the crosstalk to the neighbouring mode remains < − 15 dB for a 1-km link under calm weather, when we transmit OAM + 4 at 0.5 THz with a beam waist of 1 m; (ii) for the 3-OAM-multiplexed THz links, the signal-to-interference ratio (SIR) increases by ~ 5–7 dB if the mode spacing increases by 1, and SIR decreases with the multiplexed mode number; and (iii) limited aperture size and misalignment lead to power leakage to other modes under calm weather, while it tends to be unobtrusive under bad weather.

scholarly journals The Influence of Binaural Room Impulse Responses on Externalization in Virtual Reality Scenarios

2021 ◽  
Vol 11 (21) ◽  
pp. 10198
Author(s):  
Song Li ◽  
Roman Schlieper ◽  
Aly Tobbala ◽  
Jürgen Peissig
Keyword(s):  
Virtual Reality ◽  
Acoustic Properties ◽  
Auditory Information ◽  
Impulse Responses ◽  
The Real ◽  
Visual Impression ◽  
Sound Image ◽  
Divergence Effect

A headphone-based virtual sound image can not be perceived as perfectly externalized if the acoustic of the synthesized room does not match that of the real listening environment. This effect has been well explored and is known as the room divergence effect (RDE). The RDE is important for perceived externalization of virtual sounds if listeners are aware of the room-related auditory information provided by the listening environment. In the case of virtual reality (VR) applications, users get a visual impression of the virtual room, but may not be aware of the auditory information of this room. It is unknown whether the acoustic congruence between the synthesized (binaurally rendered) room and the visual-only virtual listening environment is important for externalization. VR-based psychoacoustic experiments were performed and the results reveal that perceived externalization of virtual sounds depends on listeners’ expectations of the acoustic of the visual-only virtual room. The virtual sound images can be perceived as externalized, although there is an acoustic divergence between the binaurally synthesized room and the visual-only virtual listening environment. However, the “correct” room information in binaural sounds may lead to degraded externalization if the acoustic properties of the room do not match listeners’ expectations.

A note on the divergence effect and the Lagrangian-mean surface elevation in periodic water waves

1988 ◽  
Vol 189 ◽  
pp. 235-242 ◽  
Author(s):  
M. E. Mcintyre
Keyword(s):  
Free Surface ◽  
Velocity Field ◽  
Gravity Waves ◽  
Water Waves ◽  
Wave Amplitude ◽  
Exact Expression ◽  
Mean Velocity ◽  
Surface Gravity Waves ◽  
Generalized Lagrangian ◽  
Divergence Effect

Longuet-Higgins’ exact expression for the increase in the Lagrangian-mean elevation of the free surface due to the presence of periodic, irrotational surface gravity waves is rederived from generalized Lagrangian-mean theory. The raising of the Lagrangian-mean surface as wave amplitude builds up illustrates the non-zero divergence of the Lagrangian-mean velocity field in an incompressible fluid.

scholarly journals A cut-off low in southern South America: dynamic and thermodynamic processes

2011 ◽  
Vol 26 (4) ◽  
pp. 503-514 ◽  
Author(s):  
Alejandro Anibal Godoy ◽  
Norma Edit Possia ◽  
Claudia Marcela Campetella ◽  
Yanina García Skabar
Keyword(s):  
Lower Troposphere ◽  
Pressure System ◽  
Horizontal Advection ◽  
The Andes ◽  
The Pacific ◽  
Divergence Effect ◽  
The Pacific Ocean ◽  
Cutoff Low ◽  
Upper Level ◽  
Thermodynamic Processes

The dynamic and thermodynamic processes involved in the life cycle of a cutoff low occurred in March 2007 are studied. These processes are analyzed using the vorticity and thermodynamic equations and a set of analyses generated with the BRAMS model. The main processes that explain the segregation of the subtropical part of the trough are the horizontal advection of cyclonic vorticity at high levels and warm horizontal advection at middle levels, both over the Pacific Ocean extending south to the Patagonia region, building the ridge located upstream of the trough. Increased intensity of the upper level low pressure system is mainly explained by intensification of the ridges down and upstream. The divergence effect is opposed to the horizontal advection of vorticity which explains the stagnation of the cut-off low windward of the Andes. The decay stage is dominated by warm vertical advection. Assuming the conservation of potential vorticity the analysis of parcel trajectories , allowed detecting the entrance of stratospheric air to middle levels of the lower troposphere around the cut-off low.

scholarly journals The Self-Other Divergence Effect for Doping Likelihood: Mediation by Guilt and Moderation by Moral Agency and Values

2020 ◽  
Vol 42 (5) ◽  
pp. 417-423 ◽  
Author(s):  
Christopher Ring ◽  
Maria Kavussanu ◽  
Benjamin Walters
Keyword(s):  
Repeated Measures ◽  
Moral Agency ◽  
The Self ◽  
Repeated Measures Design ◽  
In Doping ◽  
Quasi Experimental ◽  
Divergence Effect ◽  
Independent Variable ◽  
Rugby Players

Objectives: Self–other divergence refers to individuals judging themselves to be different from others. The authors investigated doping-related self-other divergence.Design: The authors used a quasi-experimental repeated-measures design to compare the effects of an independent variable (perspective: self, other) on doping likelihood and guilt. Method: Rugby players rated doping likelihood and guilt in situations describing two perspectives: self (their own behavior and feelings) and other (another player’s behavior and feelings). They also completed measures of moral agency, identity, perfectionism, and values (moral traits). Results: Doping likelihood was lower and guilt was higher for self-based ratings compared with other-based ratings. The self–other difference in doping likelihood was mediated by guilt and moderated by moral traits (larger for athletes with higher agency and values). Agency and values were more strongly related to self than other doping likelihood. Conclusions: Other-referenced measures differed from self-referenced measures of doping likelihood and guilt, indicating that it is wrong to presume equivalence of measurement.

scholarly journals The Xbox/Kinect use in poststroke rehabilitation settings: a systematic review

2020 ◽  
Vol 78 (6) ◽  
pp. 361-369
Author(s):  
Túlio Brandão XAVIER-ROCHA ◽  
Lara CARNEIRO ◽  
Gustavo Celestino MARTINS ◽  
Guanis de Barros VILELA-JÚNIOR ◽  
Ricardo Pablo PASSOS ◽  
...  
Keyword(s):  
Virtual Reality ◽  
Postural Balance ◽  
Research Strategy ◽  
Eligibility Criteria ◽  
Stroke Treatment ◽  
Technology Application ◽  
Rehabilitation Programs ◽  
Divergence Effect ◽  
Xbox Kinect ◽  
Clinical Conditions

ABSTRACT Background: Active games based on virtual reality have been widely used in the rehabilitation of many clinical conditions. However, studies on the use of Xbox/Kinect are rare, and technology application in stroke treatment is not clear yet. Objective: To verify the outcomes (O) analyzed in randomized controlled trials (C; S) that investigated the use of Xbox/Kinect (I) in patients with stroke (P). Methods: This is a systematic literature review that meets PRISMA standards and the eligibility criteria according to the PICOS strategy. The search procedure was performed by two researchers. The research strategy was repeated in case of divergence. Effect size was calculated by Cohen's formula and Hopkins rank. The risk of individual bias was assessed using PEDro Score and Higgins Classification. Results: The main outcomes were postural balance and activities of daily living, with four studies addressing these variables. However, only one study showed the effect of Xbox/Kinect intervention on balance as large, as in two other studies evaluating manual dexterity and depression, respectively. Conclusion: The greater use of Xbox/Kinect in treating patients after stroke is in recovery of balance and motor function, and the evidence support its application. These findings enable the use of virtual reality technology through Xbox/Kinect in rehabilitation programs, focusing on postural balance and motor skills. However, conclusive results are still not possible. Therefore, caution in the use of this technology is required.

Seismogram synthesis for radially layered media using the generalized reflection/transmission coefficients method: Theory and applications to acoustic logging

Geophysics ◽  
1996 ◽  
Vol 61 (4) ◽  
pp. 1150-1159 ◽  
Author(s):  
Xiaofei Chen ◽  
Youli Quan ◽  
Jerry M. Harris
Keyword(s):  
Seismic Profiles ◽  
P Waves ◽  
Transmission Coefficients ◽  
Full Waveform ◽  
Hankel Functions ◽  
Damaged Zone ◽  
Divergence Effect ◽  
Zone Velocity ◽  
New Formulation ◽  
Sonic Logging

A new method based on generalized reflection and transmission coefficients is proposed to calculate the synthetic seismograms in radially multilayered media. This method can be used to efficiently simulate full waveform acoustic logs and crosswell seismic profiles in situations where we need to consider borehole effects. The new formulation is tested by comparing our numerical results with previous available work and shows excellent agreement. Because of the use of the normalized Hankel functions and the normalization factors, this new algorithm for computing seismograms is stable numerically even for high‐frequency problems. To show the applicability of this new approach to full waveform sonic logging, we apply it to investigate the effects of complex invaded zones on the geometrical spreading and attenuation estimation for P‐waves. We find that a damaged zone (its velocity is slower than the unperturbed formation velocity) exhibits a convergence effect on the P‐waves, and a flushed zone (velocity is faster than the unperturbed formation velocity) exhibits a divergence effect on the P‐waves.

Instrumentation for Total Reflection Fluorescent X-Ray Spectrometry

1991 ◽  
Vol 35 (B) ◽  
pp. 933-940
Author(s):  
Tadashi Utaka ◽  
Tomoya Arai
Keyword(s):  
Surface Roughness ◽  
Lower Limit ◽  
Limit Of Detection ◽  
Incident Beam ◽  
Silicon Wafers ◽  
Total Reflection ◽  
Angular Divergence ◽  
X Ray ◽  
Divergence Effect ◽  
Beam Surface

AbstractThis article describes the instrumentation for a total reflection fluorescent x-ray spectrometer. The reflecting intensity and the angular divergence were studied with respect to various kinds of monochromators. Using silicon wafers, the angular divergence effect of the incident beam, surface roughness influences and the smoothing of background x-ray intensity for the improvement of the lower limit of detection were investigated.

scholarly journals Divergence of sun-rays by atmospheric refraction at large solar zenith angles

2004 ◽  
Vol 4 (2) ◽  
pp. 2037-2054
Author(s):  
R. Uhl ◽  
T. Reddmann
Keyword(s):  
Solar Irradiance ◽  
Rayleigh Scattering ◽  
Optical Transmittance ◽  
Optical Path ◽  
Spherically Symmetric ◽  
Atmospheric Refraction ◽  
Relative Enhancement ◽  
Photolysis Rates ◽  
Divergence Effect

Abstract. For the determination of photolysis rates at large zenith angles it has been demonstrated that refraction by the earth's atmosphere must be taken into account. In fact, due to the modified optical path the optical transmittance is thereby increased in most instances. Here we show that in addition the divergence of sun-rays, which is also caused by refraction but which reduces the direct solar irradiance, should not be neglected. Our calculations are based on a spherically symmetric atmosphere and include extinction by Rayleigh scattering, ozone, and background aerosol. For rays with 10 km tangent altitude the divergence yields a reduction of about 10% to 40% at solar zenith angles of 91° to 96°. Moreover, we find that the divergence effect can completely cancel the relative enhancement caused by the increase of transmittance.

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