scholarly journals Revisiting the Lognormal Modelling of Shadowing Effects during Wireless Communications by Means of the α-μ/α-μ Composite Distribution

Modelling ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 197-209
Author(s):  
Luan C. S. M. Ozelim ◽  
Ugo S. Dias ◽  
Pushpa N. Rathie
Keyword(s):  
Closed Form ◽  
Point Of View ◽  
Real Field ◽  
Inverse Gamma ◽  
Slow Fading ◽  
Fast Fading ◽  
Shadowing Effects ◽  
Stochastic Phenomena ◽  
Open Question ◽  
Composite Distribution

Properly modeling the shadowing effects during wireless transmissions is crucial to perform the network quality assessment. From a mathematical point of view, using composite distributions allows one to combine both fast fading and slow fading stochastic phenomena. Numerous statistical distributions have been used to account for the fast fading effects. On the other hand, even though several studies indicate the adequacy of the Lognormal distributon (LNd) as a shadowing model, they also reveal this distribution renders some analytic tractability issues. Past works include the combination of Rayleigh and Weibull distributions with LNd. Due to the difficulty inherent to obtaining closed form expressions for the probability density functions involved, other authors approximated LNd as a Gamma distribution, creating Nakagami-m/Gamma and Rayleigh/Gamma composite distributions. In order to better mimic the LNd, approximations using the inverse Gamma and the inverse Nakagami-m distributions have also been considered. Although all these alternatives were discussed, it is still an open question how to effectively use the LNd in the compound models and still get closed-form results. We present a novel understanding on how the α-μ distribution can be reduced to a LNd by a limiting procedure, overcoming the analytic intractability inherent to Lognormal fading processes. Interestingly, new closed-form and series representations for the PDF and CDF of the composite distributions are derived. We build computational codes to evaluate all the expression hereby derived as well as model real field trial results by the equations developed. The accuracy of the codes and of the model are remarkable.

scholarly journals The effectiveness of talent management strategies in the development of human resources teaching from the point of view of the leaders and members of the faculty of Taibah University

2019 ◽  
Vol 3 (15) ◽  
Author(s):  
Badrya Abdullah Al-Skran
Keyword(s):  
Professional Development ◽  
Human Resources ◽  
Human Resource Development ◽  
Human Resource ◽  
Management Strategies ◽  
Resource Development ◽  
Talent Management ◽  
Point Of View ◽  
The University ◽  
Open Question

The study aimed to identify the effectiveness of talent management strategies in human resource development at the University of Taibah, And to develop the necessary scientific solutions and recommendations, which can contribute to enhancing the effectiveness of talent management strategies in human resource development. Using the descriptive approach, study sample consisted of 67 leader, the leader of the 95 representing the entire community of the original study, and88member of the faculty members out of 365. The study relied on questionnaire tool, included thirty-eight parts, distributed over four axes, polarization, the discovery, the professional development, and the retention. In addition to an open question. The study found a range of results, which are; The general grade of the effectiveness of talent management strategies in human resources development at the University of Taibah from the perspective of leaders and members of the faculty average, is a mean 3.13.The polarization strategy is the most effective in the talent management in the development of human resources at the University of Taibah, a mean 3.35. The second was professional development with an average (3.17) and third discovery with an average of (3.09) The retention strategy came to be the least strategy in the talent management effectiveness in human resource development at the University of Taibah, a mean 2.93.In light of the results , a number of recommendations and suggestions.

scholarly journals How the Chemical Properties of GBCAs Influence Their Safety Profiles In Vivo

Molecules ◽  
2021 ◽  
Vol 27 (1) ◽  
pp. 58
Author(s):  
Quyen N. Do ◽  
Robert E. Lenkinski ◽  
Gyula Tircso ◽  
Zoltan Kovacs
Keyword(s):  
Human Brain ◽  
Chemical Properties ◽  
Point Of View ◽  
Water Soluble ◽  
Soluble Form ◽  
Clinical Implications ◽  
Kinetic Properties ◽  
Gadolinium Retention ◽  
Open Question

The extracellular class of gadolinium-based contrast agents (GBCAs) is an essential tool for clinical diagnosis and disease management. In order to better understand the issues associated with GBCA administration and gadolinium retention and deposition in the human brain, the chemical properties of GBCAs such as relative thermodynamic and kinetic stabilities and their likelihood of forming gadolinium deposits in vivo will be reviewed. The chemical form of gadolinium causing the hyperintensity is an open question. On the basis of estimates of total gadolinium concentration present, it is highly unlikely that the intact chelate is causing the T1 hyperintensities observed in the human brain. Although it is possible that there is a water-soluble form of gadolinium that has high relaxitvity present, our experience indicates that the insoluble gadolinium-based agents/salts could have high relaxivities on the surface of the solid due to higher water access. This review assesses the safety of GBCAs from a chemical point of view based on their thermodynamic and kinetic properties, discusses how these properties influence in vivo behavior, and highlights some clinical implications regarding the development of future imaging agents.

Aminergic fluorescence in the cephalopod brain

1980 ◽  
Vol 291 (1046) ◽  
pp. 127-145 ◽  
Keyword(s):  
Glyoxylic Acid ◽  
Green Fluorescence ◽  
Histochemical Technique ◽  
Yellow Fluorescence ◽  
Slow Fading ◽  
Fast Fading ◽  
Photographic Evidence

A fluorescence histochemical technique with glyoxylic acid has been employed to locate the catecholamines noradrenalin and dopamine and the indolealkylamine 5-hydroxytryptamine (5HT) in the brains of a number of genera of cephalopods. The slow-fading green fluorescence typical of noradrenalin and dopamine was located in the neuropil of most lobes and in some of the cell bodies of the superior and posterior buccal lobes, the median basal, magnocellular and vasomotor lobes. Fast-fading fluorescence typical of 5HT was associated with green fluorescence in the neuropil of the peduncle, anterior basal, olfactory, subpedunculate, subvertical, precommissural, superior buccal, optic, pedal and brachial lobes. Only the optic gland displayed yellow fluorescence alone. Photographic evidence is presented to emphasize that in the cephalopod brain the fluorescence is not uniformly distributed. The possibility that noradrenalin, dopamine and 5HT have specific neurotransmitter functions is discussed.

scholarly journals The Deceleration of Radio/Light Transmission; A Collision Mechanism Dependent Radio Signal Emission, Transmission, and Reception

2021 ◽  
Author(s):  
Jing Zhang
Keyword(s):  
Light Transmission ◽  
Radio Signal ◽  
Slow Fading ◽  
Fast Fading ◽  
Before And After ◽  
Radio Signals ◽  
Electron Photon ◽  
The Relationship ◽  
Group Pattern ◽  
Collision Mechanism

Abstract The fast and slow fading of radio signal transmissions or laser beam itself and its spare light confirm the presence of two kinds of collisions --- electron-photon and photon-photon collision. Photon transmissions of radio signals are either in consecutive dense photon groups in slow fading process or widespread group pattern in fast fading form. The photon transmission shapes are irregular and dynamical changes. The radio frequency shift and the wavelength reduction by the calculation demonstrate decelerations of radio/light transmission speeds due to the gradual reduced distance between two consecutive photon groups along the transmission pathway. Photons from radio signals are able to affect electron movements in radio signal receiving process and electrons able to kick photons into space during radio signal emission. The pattern of free electron movement under the influence of local electromagnetic force in antenna is consistent with the randomly dynamic changes of radio signal in space. The fast fading is due to the collision of consecutive photon groups of signals in slow fading with free photons in space. The mathematical equation for the relationship between light/radio transmission speeds before and after photons collisions is established. The equation is confirmed by the calculations of well-known difference of light transmission speeds in different media. The gravities from Earth and Sun play little role during light/radio transmission.

scholarly journals The Deceleration of Radio/Light Transmission; A Collision Mechanism Dependent Radio Signal Emission, Transmission, and Reception

2021 ◽  
Author(s):  
Jing Zhang
Keyword(s):  
Light Transmission ◽  
Radio Signal ◽  
Slow Fading ◽  
Fast Fading ◽  
Before And After ◽  
Radio Signals ◽  
Electron Photon ◽  
The Relationship ◽  
Group Pattern ◽  
Collision Mechanism

Abstract The fast and slow fading of radio signal transmissions or laser beam itself and its spare light confirm the presence of two kinds of collisions --- electron-photon and photon-photon collision. Photon transmissions of radio signals are either in consecutive dense photon groups in slow fading process or widespread group pattern in fast fading form. The photon transmission shapes are irregular and dynamical changes. The radio frequency shift and the wavelength reduction by the calculation demonstrate decelerations of radio/light transmission speeds due to the gradual reduced distance between two consecutive photon groups along the transmission pathway. Photons from radio signals are able to affect electron movements in radio signal receiving process and electrons able to kick photons into space during radio signal emission. The pattern of free electron movement under the influence of local electromagnetic force in antenna is consistent with the randomly dynamic changes of radio signal in space. The fast fading is due to the collision of consecutive photon groups of signals in slow fading with free photons in space. The mathematical equation for the relationship between light/radio transmission speeds before and after photons collisions is established. The equation is confirmed by the calculations of well-known difference of light transmission speeds in different media. The gravities from Earth and Sun play little role during light/radio transmission.

scholarly journals GEOMETRIC WEIGHT-SHIFTING OPERATORS ON HILBERT MODULAR FORMS IN CHARACTERISTIC p

2021 ◽  
pp. 1-60
Author(s):  
Fred Diamond
Keyword(s):  
Modular Forms ◽  
Point Of View ◽  
Real Field ◽  
Hilbert Modular Forms ◽  
Prior Work ◽  
Characteristic P ◽  
Hilbert Modular ◽  
Totally Real ◽  
Weight Shifting ◽  
Geometric Weight

Abstract We carry out a thorough study of weight-shifting operators on Hilbert modular forms in characteristic p, generalising the author’s prior work with Sasaki to the case where p is ramified in the totally real field. In particular, we use the partial Hasse invariants and Kodaira–Spencer filtrations defined by Reduzzi and Xiao to improve on Andreatta and Goren’s construction of partial $\Theta $ -operators, obtaining ones whose effect on weights is optimal from the point of view of geometric Serre weight conjectures. Furthermore, we describe the kernels of partial $\Theta $ -operators in terms of images of geometrically constructed partial Frobenius operators. Finally, we apply our results to prove a partial positivity result for minimal weights of mod p Hilbert modular forms.

scholarly journals Geometric Rényi Divergence and its Applications in Quantum Channel Capacities

2021 ◽  
Author(s):  
Kun Fang ◽  
Hamza Fawzi
Keyword(s):  
Quantum Information ◽  
Quantum Channel ◽  
Distance Measure ◽  
Point Of View ◽  
Information Measures ◽  
Rényi Divergence ◽  
A Chain ◽  
The Right ◽  
Almost All ◽  
Open Question

AbstractHaving a distance measure between quantum states satisfying the right properties is of fundamental importance in all areas of quantum information. In this work, we present a systematic study of the geometric Rényi divergence (GRD), also known as the maximal Rényi divergence, from the point of view of quantum information theory. We show that this divergence, together with its extension to channels, has many appealing structural properties, which are not satisfied by other quantum Rényi divergences. For example we prove a chain rule inequality that immediately implies the “amortization collapse” for the geometric Rényi divergence, addressing an open question by Berta et al. [Letters in Mathematical Physics 110:2277–2336, 2020, Equation (55)] in the area of quantum channel discrimination. As applications, we explore various channel capacity problems and construct new channel information measures based on the geometric Rényi divergence, sharpening the previously best-known bounds based on the max-relative entropy while still keeping the new bounds single-letter and efficiently computable. A plethora of examples are investigated and the improvements are evident for almost all cases.

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