scholarly journals Set-Valued Control Approach Applied to a COVID-19 Model with Screening and Saturated Treatment Function

Complexity ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Mohamed Elhia ◽  
Lahoucine Boujallal ◽  
Meryem Alkama ◽  
Omar Balatif ◽  
Mostafa Rachik
Keyword(s):  
Continuous Selection ◽  
Model Parameters ◽  
Viability Theory ◽  
Nonlinear Mathematical Model ◽  
The Real ◽  
Control Approach ◽  
Treatment Function ◽  
Reported Data ◽  
Saturated Treatment ◽  
Selection Of

The purpose of this paper is modelling and controlling the spread of COVID-19 disease in Morocco. A nonlinear mathematical model with two subclasses of infectious individuals is proposed. The population is divided into five classes, namely, susceptible (S), exposed (E), undiagnosed infectious ( I n c ), diagnosed patients ( I c ), and removed individuals. To reflect the real dynamic of the COVID-19 transmission in Morocco, the real reported data are used for estimating model parameters. Two controls representing screening effort and limited treatment are considered. Based on viability theory and set-valued analysis, a Lyapunov function is constructed such that both exposed and infected populations are decreased to zero asymptotically. The corresponding controls are derived via a continuous selection of adequately designed feedback map. Numerical simulations are presented with three scenarios (cases when each control is used alone and the case when two controls are combined). Our results show that when only one control is to be applied, screening is the most effective in decreasing the number of people in the three infected compartments, whereas combining both controls is found to be highly effective and leads to a significant improvement in the epidemiological situation of Morocco. To the best of our knowledge, this work is the first one that applies the set-valued approach to a controlled COVID-19 model which agrees with the observed cases in Morocco.

scholarly journals A Theoretical Model for the Transmission Dynamics of the Buruli Ulcer with Saturated Treatment

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Ebenezer Bonyah ◽  
Isaac Dontwi ◽  
Farai Nyabadza
Keyword(s):  
Human Population ◽  
Reproduction Number ◽  
Buruli Ulcer ◽  
Coupled System ◽  
Model Parameters ◽  
The Public ◽  
Treatment Function ◽  
Medical Facilities ◽  
The Stability ◽  
Saturated Treatment

The management of the Buruli ulcer (BU) in Africa is often accompanied by limited resources, delays in treatment, and macilent capacity in medical facilities. These challenges limit the number of infected individuals that access medical facilities. While most of the mathematical models with treatment assume a treatment function proportional to the number of infected individuals, in settings with such limitations, this assumption may not be valid. To capture these challenges, a mathematical model of the Buruli ulcer with a saturated treatment function is developed and studied. The model is a coupled system of two submodels for the human population and the environment. We examine the stability of the submodels and carry out numerical simulations. The model analysis is carried out in terms of the reproduction number of the submodel of environmental dynamics. The dynamics of the human population submodel, are found to occur at the steady states of the submodel of environmental dynamics. Sensitivity analysis is carried out on the model parameters and it is observed that the BU epidemic is driven by the dynamics of the environment. The model suggests that more effort should be focused on environmental management. The paper is concluded by discussing the public implications of the results.

scholarly journals Parameter Optimization for Real-World ENSO Forecast in an Intermediate Coupled Model

2019 ◽  
Vol 147 (5) ◽  
pp. 1429-1445 ◽  
Author(s):  
Yuchu Zhao ◽  
Zhengyu Liu ◽  
Fei Zheng ◽  
Yishuai Jin
Keyword(s):  
Data Assimilation ◽  
Parameter Optimization ◽  
Real World ◽  
Climate Models ◽  
Coupled Model ◽  
Prediction Skill ◽  
Model Parameters ◽  
Real World Data ◽  
The Real ◽  
Advection Term

Abstract We performed parameter estimation in the Zebiak–Cane model for the real-world scenario using the approach of ensemble Kalman filter (EnKF) data assimilation and the observational data of sea surface temperature and wind stress analyses. With real-world data assimilation in the coupled model, our study shows that model parameters converge toward stable values. Furthermore, the new parameters improve the real-world ENSO prediction skill, with the skill improved most by the parameter of the highest climate sensitivity (gam2), which controls the strength of anomalous upwelling advection term in the SST equation. The improved prediction skill is found to be contributed mainly by the improvement in the model dynamics, and second by the improvement in the initial field. Finally, geographic-dependent parameter optimization further improves the prediction skill across all the regions. Our study suggests that parameter optimization using ensemble data assimilation may provide an effective strategy to improve climate models and their real-world climate predictions in the future.

Gabriela Mistral

1946 ◽  
Vol 3 (02) ◽  
pp. 168-189
Author(s):  
Margaret J. Bates
Keyword(s):  
Nobel Prize ◽  
Gabriela Mistral ◽  
The Real ◽  
Spanish Speaking ◽  
Fundamental Reason ◽  
Selection Of

When, on November sixteenth last, the newspapers announced the awarding of the Nobel Prize for literature to a Chilean poetess, Gabriela Mistral, the news came as a surprise to many Americans, who, although they considered themselves well read, had never heard her name. The fundamental reason we know so little of this remarkable woman who enjoys such a great popularity in the Spanish-speaking world, not only for her words but for her deeds, is because the limited number of her poems which have been translated into English, by heavy hands, for the most part, allow hardly a glimmer of the real Mistral to shine through them. Of course, all translation of poetry is difficult but that of Gabriela extremely so because of her unique selection of words. She has created a plant that does not grow on English soil.

scholarly journals Continuous Selection of the Fastest Growing Species in the Chemostat

2008 ◽  
Vol 41 (2) ◽  
pp. 9707-9712 ◽  
Author(s):  
Pierre Masci ◽  
Olivier Bernard ◽  
Frédéric Grognard
Keyword(s):  
Continuous Selection ◽  
Selection Of

scholarly journals Stability and Bogdanov-Takens Bifurcation of an SIS Epidemic Model with Saturated Treatment Function

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Yanju Xiao ◽  
Weipeng Zhang ◽  
Guifeng Deng ◽  
Zhehua Liu
Keyword(s):  
Sufficient Conditions ◽  
Global Dynamics ◽  
Sis Model ◽  
Delayed Treatment ◽  
Sis Epidemic Model ◽  
Treatment Function ◽  
Lyapunov Coefficient ◽  
Saturated Treatment ◽  
Theoretical Results ◽  
Disease Free

This paper introduces the global dynamics of an SIS model with bilinear incidence rate and saturated treatment function. The treatment function is a continuous and differential function which shows the effect of delayed treatment when the rate of treatment is lower and the number of infected individuals is getting larger. Sufficient conditions for the existence and global asymptotic stability of the disease-free and endemic equilibria are given in this paper. The first Lyapunov coefficient is computed to determine various types of Hopf bifurcation, such as subcritical or supercritical. By some complex algebra, the Bogdanov-Takens normal form and the three types of bifurcation curves are derived. Finally, mathematical analysis and numerical simulations are given to support our theoretical results.

scholarly journals On the ship course-keeping control system design by using robust feedback linearization

2013 ◽  
Vol 20 (1) ◽  
pp. 70-76 ◽  
Author(s):  
Zenon Zwierzewicz
Keyword(s):  
Feedback Linearization ◽  
High Performance ◽  
Linearization Method ◽  
Model Parameters ◽  
Control System Design ◽  
Control Approach ◽  
Ship Model ◽  
Control Techniques ◽  
System Nonlinearity ◽  
Ship Autopilot

Abstract In the paper the problem of ship autopilot design based on feedback linearization method combined with the robust control approach, is considered. At first the nonlinear ship model (of Norrbin type) is linearized with the use of the simple system nonlinearity cancellation. Next, bearing in mind that exact values of the model parameters are not known, the ensuing inaccuracies are taken as disturbances acting on the system. Thereby is obtained a linear system with an extra term representing the uncertainty which can be treated by using robust, H∞ optimal control techniques. The performed simulations of ship course-changing process confirmed a high performance of the proposed controller despite the assumed significant errors of its parameters.

scholarly journals Strategi Kampanye Gubernur Basuki Tjahaja Purnama-Djarot Saiful Hidayat Dalam Menghadapi Pilkada Dki Jakarta 2017

2018 ◽  
Vol 10 (2) ◽  
pp. 142
Author(s):  
Rahmadya Putra Nugraha ◽  
Anastasya Christy Puspitasari
Keyword(s):  
Social Construction ◽  
Descriptive Analysis ◽  
Social Reality ◽  
Social Situation ◽  
Analysis Method ◽  
Campaign Strategy ◽  
The Real ◽  
Qualitative Descriptive ◽  
Gubernatorial Election ◽  
Selection Of

The selection of the 2017 DKI Jakarta governor was attended by 3 candidates, including the pair Agus Harimurti - Sylviana Murni, the pair Basuki Tjahaja Purnama - Djarot Saiful Hidayat and the couple Anies Baswedan - Sandiaga Uno. Basuki Tjahaj Purnama - Djarot Saiful Hidayat is a pair of incumbent governors who again competed in this gubernatorial election. The researcher focused on research to find out how the strategy used by the incumbent governor pair in facing the 2017 DKI Jakarta gubernatorial election. In this case, the author uses the Constructivist paradigm, namely, the truth of a social reality seen as a result of social construction, and the truth of a social reality is relative. The type of research used is descriptive, which describes a social situation as it is by using a qualitative descriptive analysis method. Based on this research regarding the campaign strategy of Basuki Tjahaja Purnama - Djarot Saiful Hidayat in facing the gubernatorial election, the researchers concluded that the pair Basuki Tjahaja Purnama - Djarot Saiful Hidayat possessed and re-demonstrated the real program that was directly felt by the community and also maximized the entire media to socialize their upcoming programs. Pemilihan gubernur DKI Jakarta 2017 diikuti oleh 3 pasangan calon antara lain pasangan Agus Harimurti – Sylviana Murni, Basuki Tjahaja Purnama – Djarot Saiful Hidayat dan Anies Baswedan – Sandiaga Uno. Pasangan Basuki Tjahaj Purnama – Djarot Saiful Hidayat adalah pasangan gubernur petahana yang kembali bersaing dalam pemilihan gubernur ini. Peneliti memfokuskan penelitian untuk mengetahui bagaimana strategi yang digunakan oleh pasangan gubernur petahana dalam menghadapi pemilihan gubernur DKI Jakarta 2017 ini. Dalam hal ini, penulis menggunakan paradigma Konstruktivis yaitu,  kebenaran suatu realitas sosial dilihat sebagai hasil konstruksi sosial, dan kebenaran suatu realitas sosial bersifat relatif.  Tipe penelitian yang digunakan dalam penelitian yaitu deskriptif, yang menggambarkan suatu keadaan sosial secara apa adanya dengan menggunakan metode analisis deskriptif kualitatif. Berdasarkan penelitian ini mengenai strategi kampanye Basuki Tjahaja Purnama – Djarot Saiful Hidayat dalam menghadapi pemilihan gubernur, maka peneliti membuat kesimpulan bahwa pasangan Basuki Tjahaja Purnama - Djarot Saiful Hidayat memiliki dan menunjukkan kembali program nyata yang sudah dirasakan langsung oleh masyarakat dan juga pasangan ini memaksimalkan seluruh media untuk mensosialisasikan program mereka yang akan datang.

scholarly journals Learning Personalized Itemset Mapping for Cross-Domain Recommendation

2020 ◽  
Author(s):  
Yinan Zhang ◽  
Yong Liu ◽  
Peng Han ◽  
Chunyan Miao ◽  
Lizhen Cui ◽  
...  
Keyword(s):  
Single Domain ◽  
Model Parameters ◽  
The Real ◽  
Cross Domain ◽  
Proposed Model ◽  
Latent Space ◽  
Learning Parameter ◽  
Generation Procedure ◽  
Over Time

Cross-domain recommendation methods usually transfer knowledge across different domains implicitly, by sharing model parameters or learning parameter mappings in the latent space. Differing from previous studies, this paper focuses on learning explicit mapping between a user's behaviors (i.e. interaction itemsets) in different domains during the same temporal period. In this paper, we propose a novel deep cross-domain recommendation model, called Cycle Generation Networks (CGN). Specifically, CGN employs two generators to construct the dual-direction personalized itemset mapping between a user's behaviors in two different domains over time. The generators are learned by optimizing the distance between the generated itemset and the real interacted itemset, as well as the cycle-consistent loss defined based on the dual-direction generation procedure. We have performed extensive experiments on real datasets to demonstrate the effectiveness of the proposed model, comparing with existing single-domain and cross-domain recommendation methods.

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