scholarly journals Application of a Semi-Empirical Dynamic Model to Forecast the Propagation of the COVID-19 Epidemics in Spain

Forecasting ◽  
2020 ◽  
Vol 2 (4) ◽  
pp. 452-469
Author(s):  
Juan Carlos Mora ◽  
Sandra Pérez ◽  
Alla Dvorzhak
Keyword(s):  
Mathematical Model ◽  
Intensive Care ◽  
Good Accuracy ◽  
Logistic Map ◽  
Semiempirical Model ◽  
The Third ◽  
Third Phase ◽  
Daily Rate ◽  
Semi Empirical ◽  
The Mathematical Model

A semiempirical model, based in the logistic map, was developed to forecast the different phases of the COVID-19 epidemic. This paper shows the mathematical model and a proposal for its calibration. Specific results are shown for Spain. Four phases were considered: non-controlled evolution; total lock-down; partial easing of the lock-down; and a phased lock-down easing. For no control the model predicted the infection of a 25% of the Spanish population, 1 million would need intensive care and 700,000 direct deaths. For total lock-down the model predicted 194,000 symptomatic infected, 85,700 hospitalized, 8600 patients needing an Intensive Care Unit (ICU) and 19,500 deaths. The peak was predicted between the 29 March/3 April. For the third phase, with a daily rate r=1.03, the model predicted 400,000 infections and 46,000±15,000 deaths. The real r was below 1%, and a revision with updated parameters provided a prediction of 250,000 infected and 29,000±15,000 deaths. The reported values by the end of May were 282,870 infected and 28,552 deaths. After easing of the lock-down the model predicted that the health system would not saturate if r was kept below 1.02. This model provided good accuracy during epidemics development.

Development of a Mathematical Model for Performance Prediction of Planing Catamaran in Calm Water

2019 ◽  
Vol 161 (A2) ◽  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Performance Prediction ◽  
Data Evaluation ◽  
Empirical Equations ◽  
Calm Water ◽  
Semi Empirical ◽  
The Mathematical Model ◽  
Comparison With Experimental Data

In this paper, an attempt has been made to predict the performance of a planing catamaran using a mathematical model. Catamarans subjected to a common hydrodynamic lift, have an extra lift between the two asymmetric half bodies. In order to develop a mathematical model for performance prediction of planing catamarans, existing formulas for hydrodynamic lift calculation must be modified. Existing empirical and semi-empirical equations in the literature have been implemented and compared against available experimental data. Evaluation of lift in comparison with experimental data has been documented. Parameters influencing the interaction between demi-hulls and separation effects have been analyzed. The mathematical model for planing catamarans has been developed based on Savitsky’s method and results have been compared against experimental data. Finally, the effects of variation in hull geometry such as deadrise angle and distance between two half bodies on equilibrium trim angle, resistance and wetted surface have been examined.

scholarly journals Optimization of the power supply system for connection of the end user to electric grids according to the scheme of the third category of reliability

2018 ◽  
Vol 58 ◽  
pp. 02011
Author(s):  
Ivan Bandurin ◽  
Alexey Khaimin
Keyword(s):  
Mathematical Model ◽  
Power System ◽  
Power Supply ◽  
Power Supply System ◽  
Supply System ◽  
End User ◽  
The Third ◽  
Electric Grids ◽  
The Mathematical Model ◽  
Optimal Type

The article first developed a mathematical model of optimization of the power supply system for connection of the end user to electric grids according to the scheme of the third category of reliability. The mathematical model allows to choose the optimal type and brand power system equipment.

scholarly journals A simple mathematical model for Batesian mimicry

2005 ◽  
Vol 2005 (1) ◽  
pp. 87-92 ◽  
Author(s):  
Terence R. Blows ◽  
Barry J. Wimmer
Keyword(s):  
Mathematical Model ◽  
Full Range ◽  
Logistic Map ◽  
Period Doubling ◽  
Species Interaction ◽  
Batesian Mimicry ◽  
Simple Mathematical Model ◽  
Predator Prey ◽  
The Mathematical Model ◽  
Period Doubling Bifurcations

A simple mathematical model is presented for Batesian mimicry, which occurs when a harmless species (mimic) is morphologically similar to another species (model) that is noxious or distasteful to predators, thus gaining a measure of protection. Although mathematical models for species interaction, such as predator-prey or competition, are well known, there is no similar literature on mimicry. The mathematical model developed here is a one-dimensional iterated map which has the full range of dynamic behavior present in the logistic map, depending on the values of its parameters. The dynamics ranges from a stable fixed point and stable cycles through chaotic dynamics achieved through a sequence of period doubling bifurcations.

Mathematical Model and Numerical Simulation of the Concrete Regenerator

2011 ◽  
Vol 347-353 ◽  
pp. 1184-1192 ◽  
Author(s):  
Zhong Zhu Qiu ◽  
Shao Lin Gong ◽  
Peng Li ◽  
Wen Wen Guo
Keyword(s):  
Mathematical Model ◽  
Cross Sections ◽  
Heat Storage ◽  
Thermal Storage ◽  
Simulation Software ◽  
Test Model ◽  
Storage Element ◽  
The Third ◽  
Simulation Results ◽  
The Mathematical Model

In this paper, the mathematical model of Concrete Thermal Storage Element was introduced, then simulation software FLUENT was used to simulate Concrete Thermal Storage Elements of different cross sections, square, triangle, hexagon and test model. According to the simulation results, the hexagon section regenerator gets the best performance of heat storage, followed by the test model, square section regenerator is the third one, and last is triangle section regenerator.

scholarly journals Testing the classifier adapted to recognize the languages of works based on the Latin alphabet

2021 ◽  
pp. 83-94
Author(s):  
Zafar Usmanov ◽  
◽  
Abdunabi Kosimov ◽  
Keyword(s):  
Machine Learning ◽  
Mathematical Model ◽  
Learning Algorithm ◽  
Automatic Recognition ◽  
Machine Learning Algorithm ◽  
The Third ◽  
Optimal Value ◽  
Minimum Distances ◽  
Homogeneity Hypothesis ◽  
The Mathematical Model

Using the example of a model collection of 10 texts in five languages (English, German, Spanish, Italian, and French) using Latin graphics, the article establishes the applicability of the γ-classifier for automatic recognition of the language of a work based on the frequency of 26 common Latin alphabetic letters. The mathematical model of the γ-classifier is represented as a triad. Its first component is a digital portrait (DP) of the text - the distribution of the frequency of alphabetic unigrams in the text; the second component is formulas for calculating the distances between the DP texts and the third is a machine learning algorithm that implements the hypothesis of “homogeneity” of works written in one language and “heterogeneity” of works written in different languages. The tuning of the algorithm using a table of paired distances between all products of the model collection consisted in determining an optimal value of the real parameter γ, for which the error of violation of the “homogeneity” hypothesis is minimized. The γ-classifier trained on the texts of the model collection showed a high, 100% accuracy in recognizing the languages of the works. For testing the classifier, an additional six random texts were selected, of which five were in the same languages as the texts of the model collection. By the method of the nearest (in terms of distance) neighbor, all new texts confirmed their homogeneity with the corresponding pairs of monolingual works. The sixth text in Romanian showed its heterogeneity in relation to all elements of the collection. At the same time, it showed closeness in minimum distances, first of all, to two texts in Spanish and then to two works in Italian.

Modeling and Simulation of a Co-current Rotary Dryer

2016 ◽  
Vol 12 (2) ◽  
pp. 189-194 ◽  
Author(s):  
Zhi-gang Huang ◽  
Yun-xuan Weng ◽  
Nan Fu ◽  
Zong-qiang Fu ◽  
Dong Li ◽  
...  
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Moisture Content ◽  
Mathematical Models ◽  
Modeling And Simulation ◽  
Air Temperature ◽  
Good Accuracy ◽  
Rotary Dryer ◽  
Simulation Results ◽  
The Mathematical Model

Abstract Mathematical models including mass and energy conservation were developed in order to predict the outlet particles temperature and moisture. As the inlet air temperature increased, the outlet particles temperature increased as well and the outlet particles moisture decreased quickly. The outlet particles temperature and moisture changed a little as a function of the speed of rotation at the low inlet air temperature, while the outlet particles temperature and moisture increased very apparently with the speed of rotation increased at the high inlet air temperature. The error of the simulation results compared to the experimental data showed good accuracy for particles temperature and moisture content. The mathematical model performs well to predict the outlet particles temperature and moisture content.

Mathematical modelling of downflow floating medium filter (DFF) with in-line flocculation arrangement

1996 ◽  
Vol 34 (3-4) ◽  
pp. 355-362
Author(s):  
H. H. Ngo ◽  
S. Vigneswaran ◽  
V. Jegatheesan
Keyword(s):  
Mathematical Model ◽  
Suspended Solids ◽  
Filtration Velocity ◽  
Velocity Filter ◽  
Set Up ◽  
Filter Particle ◽  
Semi Empirical ◽  
Filter Bed ◽  
The Mathematical Model ◽  
Attachment Coefficient

A laboratory-scale set-up consisting of rapid mixing device and floating medium filter was used to study the use of a downflow floating medium filter (DFF) with an in-line flocculation arrangement as a static flocculator and a prefilter. The semi-empirical mathematical model formulated incorporates flocculation within the filter, particle/floc attachment onto the filter and the detachment of flocs from the medium. The mathematical model for filtration takes into account the expansion of the filter bed. The removal efficiency of DFF and headloss development were successfully simulated for different conditions of filtration velocity, filter depth and influent suspended solids (SS). The values of attachment coefficient apβ and headloss coefficient β′ were found to be independent of filtration velocity, filter depth and influent SS concentration.

MEMRISTOR MODEL AND ITS APPLICATION FOR CHAOS GENERATION

2012 ◽  
Vol 22 (08) ◽  
pp. 1250205 ◽  
Author(s):  
LIDAN WANG ◽  
EMMANUEL DRAKAKIS ◽  
SHUKAI DUAN ◽  
PENGFEI HE ◽  
XIAOFENG LIAO
Keyword(s):  
Mathematical Model ◽  
Chaotic System ◽  
Initial Conditions ◽  
Third Order ◽  
Nonlinear Part ◽  
The Third ◽  
Simulation Results ◽  
Application Fields ◽  
Model C ◽  
The Mathematical Model

This paper contributes to the understanding of memristor operation and its possible application fields through: (a) derivation of a complete mathematical model for the HP memristor which takes into consideration the inter-dependence between memristance, charge and flux along with the boundary and initial conditions of operation; (b) an introduction of detailed charge- and flux-controlled SPICE memristor models realizing the proposed mathematical memristor model; (c) The incorporation of the memristor model in the SPICE realization of a third-order chaotic system where a single HP memristor acts as the nonlinear part of the system. Simulation results are provided to validate the mathematical model and the synthesis and operation of the third-order chaotic system.

Modelling and design of friction damper used for the control of vibration in a gas-turbine blade - a microslip approach

2007 ◽  
Vol 221 (8) ◽  
pp. 887-895
Author(s):  
P V Ramaiah ◽  
G Krishnaiah
Keyword(s):  
Mathematical Model ◽  
Turbine Blade ◽  
Experimental Test ◽  
Contact Region ◽  
Modal Parameters ◽  
Second Phase ◽  
Rigid Surface ◽  
Friction Damper ◽  
The Third ◽  
Third Phase

The paper deals with modelling and design of a friction damper. This has been done in four phases. In the first phase, modal analysis is performed to determine the modal parameters of turbine blade. In the second phase, a mathematical model for the contact region of damper and rigid surface has been developed using microslip approach. This model has the ability to account for microslip in the contact region. In the third phase, a mathematical model for the combined blade with damper is developed and in the fourth phase the damper is designed. The results of the combined blade with damper model are confirmed by experimental test.

DEVELOPMENT OF A MATHEMATICAL MODEL FOR PERFORMANCE PREDICTION OF PLANING CATAMARAN IN CALM WATER

2021 ◽  
Vol 161 (A2) ◽  
Author(s):  
A Ghassemzadeh ◽  
A Dashtimanesh ◽  
M Habibiasl ◽  
P Sahoo
Keyword(s):  
Experimental Data ◽  
Mathematical Model ◽  
Performance Prediction ◽  
Data Evaluation ◽  
Empirical Equations ◽  
Calm Water ◽  
Semi Empirical ◽  
The Mathematical Model ◽  
Comparison With Experimental Data

In this paper, an attempt has been made to predict the performance of a planing catamaran using a mathematical model. Catamarans subjected to a common hydrodynamic lift, have an extra lift between the two asymmetric half bodies. In order to develop a mathematical model for performance prediction of planing catamarans, existing formulas for hydrodynamic lift calculation must be modified. Existing empirical and semi-empirical equations in the literature have been implemented and compared against available experimental data. Evaluation of lift in comparison with experimental data has been documented. Parameters influencing the interaction between demi-hulls and separation effects have been analyzed. The mathematical model for planing catamarans has been developed based on Savitsky’s method and results have been compared against experimental data. Finally, the effects of variation in hull geometry such as deadrise angle and distance between two half bodies on equilibrium trim angle, resistance and wetted surface have been examined.

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