scholarly journals Estimation of the Present Status of the Species Based on the Theoretical Bounds of Environmental Noise Intensity: An Illustration Through a Big Abundance Data and Simulation

2021 ◽  
Author(s):  
Ayan Paul ◽  
Nabakumar Ghosh ◽  
Sabyasachi Bhattacharya
Keyword(s):  
Logistic Model ◽  
Noise Intensity ◽  
Research Work ◽  
Growth Trait ◽  
Environmental Noise ◽  
Logistic Growth ◽  
Intensity Level ◽  
Intensity Parameter ◽  
Small Magnitude ◽  
Current Time

Abstract Sibly et al. (2005) described that most species have a fundamental characteristic to follow the theta-logistic growth trait with the convex downward trend. The fundamental yardstick of this research work builds under the deterministic setup, whereas the involvement of the external noise in any growth system is inevitable. But, the involvement of external affairs in any species growth can't be well judged only through its density dependence; it requires a further assessment. So, we frame the theta-logistic model with the stochastic analog in two directions, i.e., the discrete and continuous setup. The analysis of the discrete stochastic model is manifested by the bifurcation analysis, which shows that the attainment of the chaotic regime enhances with the increase in noise intensity level. Although the role of chaos in species extinction is debatable, a literature survey suggests that chaos with stochasticity accelerates the extinction of species. Similarly, in the case of the continuous version, we performed a theoretical study on the stochastic theta-logistic model to provide a critical value of the noise intensity parameter. This threshold magnitude act as the sustainability criteria of any species environmental tolerability. In this connection, we use the data of four major taxonomic groups, i.e., Bird, Insect, Mammal, and Fish, from the GPDD database and classify the species based on environmental sensitivity. The high sensitive species have a low tolerance level, associated with the small magnitude of environmental noise intensity parameter. Moreover, the simulation prediction model on these four taxonomic classes also shows that the overall extinction probability of the Bird is almost negligible for the current time window.

scholarly journals Forecasting COVID-19 cases in Algeria using logistic growth and polynomial regression models

2021 ◽  
Author(s):  
Mohamed LOUNIS ◽  
Babu Malavika
Keyword(s):  
Regression Model ◽  
Logistic Model ◽  
Polynomial Regression ◽  
Logistic Growth ◽  
The Novel ◽  
Logistic Growth Model ◽  
Polynomial Regression Models ◽  
Using Data ◽  
Novel Coronavirus ◽  
Polynomial Regression Model

Abstract The novel Coronavirus respiratory disease 2019 (COVID-19) is still expanding through the world since it started in Wuhan (China) on December 2019 reporting a number of more than 84.4 millions cases and 1.8 millions deaths on January 3rd 2021.In this work and to forecast the COVID-19 cases in Algeria, we used two models: the logistic growth model and the polynomial regression model using data of COVID-19 cases reported by the Algerian ministry of health from February 25th to December 2nd, 2020. Results showed that the polynomial regression model fitted better the data of COVID-19 in Algeria the Logistic model. The first model estimated the number of cases on January, 19th 2021 at 387673 cases. This model could help the Algerian authorities in the fighting against this disease.

scholarly journals Psi-Caputo Logistic Population Growth Model

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Muath Awadalla ◽  
Yves Yannick Yameni Noupoue ◽  
Kinda Abu Asbeh
Keyword(s):  
Population Growth ◽  
Fractional Derivative ◽  
Carrying Capacity ◽  
Chinese Population ◽  
Logistic Model ◽  
Logistic Equation ◽  
Logistic Growth ◽  
Growth Equation ◽  
Uniqueness Of The Solution ◽  
Better Than

This article studies modeling of a population growth by logistic equation when the population carrying capacity K tends to infinity. Results are obtained using fractional calculus theories. A fractional derivative known as psi-Caputo plays a substantial role in the study. We proved existence and uniqueness of the solution to the problem using the psi-Caputo fractional derivative. The Chinese population, whose carrying capacity, K, tends to infinity, is used as evidence to prove that the proposed approach is appropriate and performs better than the usual logistic growth equation for a population with a large carrying capacity. A psi-Caputo logistic model with the kernel function x + 1 performed the best as it minimized the error rate to 3.20% with a fractional order of derivative α  = 1.6455.

scholarly journals An Improved Logistic Model Illustrating Microcystis aeruginosa Growth Under Different Turbulent Mixing Conditions

Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 669
Author(s):  
Haiping Zhang ◽  
Fan Huang ◽  
Feipeng Li ◽  
Zhujun Gu ◽  
Ruihong Chen ◽  
...  
Keyword(s):  
Microcystis Aeruginosa ◽  
Growth Model ◽  
Turbulent Mixing ◽  
Logistic Model ◽  
Logistic Equation ◽  
Logistic Growth ◽  
Turbulence Mixing ◽  
Population Dynamics Models ◽  
Dynamics Models ◽  
Relationship Of

To overcome the limitations of the normal logistic equation, we aimed to improve the logistic model under hydrodynamic conditions for the examination of the responses of cyanobacterium, coupled turbulence mixing, and growth of cyanobacterium in population dynamics models. Selecting Microcystis aeruginosa and experimenting with the ideal conditions in a laboratory beaker, the chlorophyll-a concentration reached the corresponding maximum under each turbulent condition compared with the control. According to the experiment results, the theory of mass transfer, turbulence mixing, and the logistic equation are organically combined. The improved logistic growth model of Microcystis aeruginosa and competition growth model in the symbiont Scenedesmus quadricauda under turbulent conditions were established. Using the MATLAB multi-parameter surface fitting device, both models produced good fitting effects, with R > 0.95, proving that the results fit the models, and demonstrating the relationship of the unity of nutrient transfer and algae growth affected by turbulence mixing. With continuous increases in turbulent mixing, the fitted curve became smoother and steadier. Algae stimulated by turbulence accelerate reproduction and fission to achieve population dominance. The improved logistic model quantitatively explains the Microcystis aeruginosa response to turbulence and provides a basis to represent ecological and biogeochemical processes in enclosed eutrophic water bodies.

A Study of Noise Impact on the Stability of Electrostatic MEMS

2020 ◽  
Vol 15 (11) ◽  
Author(s):  
Yan Qiao ◽  
Wei Xu ◽  
Hongxia Zhang ◽  
Qin Guo ◽  
Eihab Abdel-Rahman
Keyword(s):  
Noise Intensity ◽  
Initial Conditions ◽  
Basins Of Attraction ◽  
Low Noise ◽  
Intensity Level ◽  
Lumped Mass ◽  
Mass Model ◽  
Restoring Force ◽  
Electrostatic Mems ◽  
The Stability

Abstract Noise-induced motions are a significant source of uncertainty in the response of micro-electromechanical systems (MEMS). This is particularly the case for electrostatic MEMS where electrical and mechanical sources contribute to noise and can result in sudden and drastic loss of stability. This paper investigates the effects of noise processes on the stability of electrostatic MEMS via a lumped-mass model that accounts for uncertainty in mass, mechanical restoring force, bias voltage, and AC voltage amplitude. We evaluated the stationary probability density function (PDF) of the resonator response and its basins of attraction in the presence noise and compared them to that those obtained under deterministic excitations only. We found that the presence of noise was most significant in the vicinity of resonance. Even low noise intensity levels caused stochastic jumps between co-existing orbits away from bifurcation points. Moderate noise intensity levels were found to destroy the basins of attraction of the larger orbits. Higher noise intensity levels were found to destroy the basins of attraction of smaller orbits, dominate the dynamic response, and occasionally lead to pull-in. The probabilities of pull-in of the resonator under different noise intensity level are calculated, which are sensitive to the initial conditions.

Stochastic resonance induced by a multiplicative periodic signal in a logistic growth model with correlated noises

Open Physics ◽  
2009 ◽  
Vol 7 (3) ◽  
Author(s):  
Chunyan Bai ◽  
Luchun Du ◽  
Dongcheng Mei
Keyword(s):  
Stochastic Resonance ◽  
Growth Model ◽  
Noise Intensity ◽  
Critical Phenomenon ◽  
Fixed Ratio ◽  
Logistic Growth ◽  
Periodic Signal ◽  
Logistic Growth Model ◽  
Multiplicative Periodic Signal ◽  
Correlated Noises

AbstractThe stochastic resonance (SR) phenomenon induced by a multiplicative periodic signal in a logistic growth model with correlated noises is studied by using the theory of signal-to-noise ratio (SNR) in the adiabatic limit. The expressions of the SNR are obtained. The effects of multiplicative noise intensity α and additive noise intensity D, and correlated intensity λ on the SNR are discussed respectively. It is found that the existence of a maximum in the SNR is the identifying characteristic of the SR phenomena. In comparison with the SR induced by additive periodic signal, some new features are found: (1) When SNR as a function of λ for fixed ratio of α and D, the varying of α can induce a stochastic multi-resonance, and can induce a re-entrant transition of the peaks in SNR vs λ; (2) There exhibits a doubly critical phenomenon for SNR vs D and λ, i.e., the increasing of D (or λ) can induce the critical phenomenon for SNR with respect to λ (or D); (3) The doubly stochastic resonance effect appears when α and D are simultaneously varying in SNR, i.e., the increment of one noise intensity can help the SR on another noise intensity come forth.

An Evaluation of Potential Yield of Indium Recycled from Waste Mobile Phone in China

2016 ◽  
Vol 847 ◽  
pp. 335-343 ◽  
Author(s):  
Heng Guang Wang ◽  
Yu Feng Wu ◽  
Yi Fan Gu ◽  
Xian Zhong Mu
Keyword(s):  
Mobile Phone ◽  
Mobile Phones ◽  
Logistic Model ◽  
Cell Phone ◽  
Research Work ◽  
Policy Recommendations ◽  
Relevant Research ◽  
Potential Yield ◽  
Main Factors ◽  
Conduction Properties

In recent years, users replace their mobile phone more and more frequently, therefore, the number of waste mobile phones has been increasing year by year. In 2014, the number was more than 1 billion units. Indium, that has unique optical transparency and electrical conduction properties, is a necessary element in the screen of mobile phone. The potential yield of indium recycled from waste mobile phone is considerable. Recycling indium from waste mobile phones can alleviate the constraints of indium resources while gaining great economic benefit. However, there is no relevant research work to evaluate the potential yield of indium in the waste cell phone. This paper explores the main factors that constraint the efficiency of recycling by predicting potential yield of indium recycled from waste mobile phone, and puts forward the corresponding policy recommendations. The results are based on the Logistic model and Stock-base model and a survey. The results show that the potential yield of indium recycled from waste mobile phone from 2015 to 2035 will increase from 8.7 tonnes to 10.2 tonnes in China. However, the recovery rate of waste mobile phone is very low, the actual available amount is far lower than the potential yield of indium. The main factors that constrain the efficiency of recycling are: (1) it is difficult to guarantee information security; (2) the existing recycling system is not perfect; (3) the technology of recycling indium needs to be improved.

scholarly journals Fitting a logistic growth model to yield traits of lettuce cultivars growing in summer

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Fernanda Carini ◽  
Alberto Cargnelutti-Filho ◽  
Jéssica Maronez De Souza ◽  
Rafael Vieira Pezzini ◽  
Cassiane Ubessi ◽  
...  
Keyword(s):  
Confidence Intervals ◽  
Growth Model ◽  
Iterative Process ◽  
Logistic Model ◽  
Goodness Of Fit ◽  
Least Squares Method ◽  
Logistic Growth ◽  
Model Parameters ◽  
Yield Traits ◽  
Logistic Growth Model

The objective of this study was to fit a logistic model to fresh and dry matters of leaves and fresh and dry matters of shoots of four lettuce cultivars to describe growth in summer. Cultivars Crocantela, Elisa, Rubinela, and Vera were evaluated in the summer of 2017 and 2018, in soil in protected environment and in soilless system. Seven days after transplantation, fresh and dry leaf matters and fresh and dry shoot matters of 8 plants were weighed every 4 days. The model parameters were estimated using the software R, using the least squares method and iterative process of Gauss-Newton. We also estimated the confidence intervals of the parameters, verified the assumptions of the models, calculated the goodness-of-fit measures and the critical points, and quantified the parametric and intrinsic nonlinearities. The logistic growth model fitted well to fresh and dry leaf and shoot matters of cultivars Crocantela, Elisa, Rubinela, and Vera and is indicated to describe the growth of lettuce.

Effects of Noise Intensity on Visual Target-Detection Performance

1972 ◽  
Vol 14 (2) ◽  
pp. 181-185 ◽  
Author(s):  
Harold D. Warneb ◽  
Norman W. Heimstra
Keyword(s):  
Target Detection ◽  
Noise Intensity ◽  
Target Location ◽  
Visual Target ◽  
Visual Display ◽  
Detection Performance ◽  
Difficulty Level ◽  
Intensity Level ◽  
Detection Error ◽  
Target Locations

The purpose of the present study was to determine the effects of continuous white noise on visual target-detection performance. The variables manipulated were noise-intensity level, display-difficulty level, and target location. Four noise levels were utilized: 0, 80, 90, and 100 db. The 0-db. level served as the control condition. Display difficulty was defined in terms of the number of nontarget, or background, display elements. Three levels of difficulty were used: 8, 16, and 32 background letter characters. The target locations examined were the central and peripheral regions of the visual display. Twenty subjects were tested under all conditions. Both detection time and detection error were recorded. The results indicated that noise-intensity and display-difficulty level were significantly interrelated with respect to detection speed but not to detection error.

THE RELAXATION TIME AND THE CORRELATION FUNCTION FOR A LOGISTIC GROWTH SYSTEM DRIVEN BY COLORED CROSS-CORRELATION NOISES

2008 ◽  
Vol 08 (02) ◽  
pp. L213-L228
Author(s):  
CAN-JUN WANG ◽  
DONG-CHENG MEI
Keyword(s):  
Correlation Function ◽  
Relaxation Time ◽  
Tumor Cell ◽  
Noise Intensity ◽  
Multiplicative Noise ◽  
Gaussian White Noise ◽  
Operator Method ◽  
Logistic Growth ◽  
Arbitrary Initial Condition ◽  
Growth System

The associated relaxation time Tc and the normalized correlation function C(s) are investigated in the logistic growth system, which is used to describe a tumor cell growth process, driven by two Gaussian white noise sources and the correlation between the additive and multiplicative noise. The expression of Tc and C(s), which is the function of noise parameters (additive noise intensity α, multiplicative noise intensity D, correlation intensity λ and correlation time τ), is obtained by using the projection operator method. After introducing noise intensity ratio, a dimensionless parameter R = α/D, and performing the numerical computations, the two case are analyzed: (1) In the growth case, λ and τ play opposite roles on the Tc and the C(s). It must emphasize that there is a minimal evolution velocity to appear and the tumor cell numbers is hard to evolve from an arbitrary initial condition to the maximum. (2) In the decay case, λ and τ play same roles on the Tc and the C(s). There is a maximal evolution velocity to appear. The noises induce different responses of tumor cells between the growth and decay case.

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