Stability study on geometrical time lag dynamic model for infectious diseases

2021 ◽  
Author(s):  
Guobin Zeng ◽  
Linli Zhang ◽  
Yanni Chen
Author(s):  
Pavel Syrovátka

The article is focused on the analysis of impact of the final consumer for milk on the price development on the fluid milk processing market. The impact research was based on the dynamic model of intermediate demand function in inverse form. There were examined two approaches for the dynamisation of developed models – the implicit and explicit approach. Implicit dynamic model, which was developed on the base of linear inverse demand function with time lag explanatory variable, wasn’t acceptable in the view of the achieved results of statistical and economical verification. According to this developed model, the quarterly lag in the examined vertical demand linkage did not play statistically significant role. Among explicit dynamic models, the best model with respect to results of T-test of B2 parameter got the following form:pt = +18.8854 – 0.8636 · qt* + 0.1783 · t – 2.7336 · 10–3 · t2; (t = 1, 2, ..., 32).This developed model with the explicit dynamisation fit theoretical economical condition of Law of diminishing demand and its transmission in the researched section of the product vertical – milk. The intensity of the impact of final consumer demand for milk on the price development on the market for fluid milk processing was evaluated on the base of value of B2 and on base of elasticity coefficient FPt(qt*). In view of B2, the rise of the consumer demand for milk by 1 litre implied the decrease in the prices of litre of milk on the market for fluid milk processing approximately by 0.90 CZK. According to FPt(qt*), the increase of the consumer demand for milk by 1 % bring out in average the fall of the prices per litre of milk on the fluid milk processing market by almost 0.60 %.


2020 ◽  
pp. 133-156
Author(s):  
Anar Rzayev ◽  
Anastasiia Samoilikova

The article focuses on the level and dynamics of innovation financing in Azerbaijan and Ukraine compared to the world level and the places of Azerbaijan and Ukraine in the Global Innovation Index and trends in their positioning in the dynamics. The analysis reveals negative dynamics in both countries in this sphere. The innovation financing structure's role as a factor of economic growth and international reproductive relations development is substantiated. The dependence of the country's economic growth level (GDP growth per capita) on the value of expenditures on innovation financed by various sectors of the economy (government, the private non-profit sector, foreign investors and the higher education sector) is studied. The study consists of data for 12 European countries for 2007-2017 (limited calculations in 2017 due to the availability of information on open portals of the World Bank, the EU Statistical Office). At the first stage, the distribution of the relevant indicators was evaluated using the Shapiro-Wilk test. Based on these results the method of calculating the correlation coefficient is chosen: Pearson – for indices that are subject to the ordinary distribution law or Spearman – for indices that are not subject to the ordinary distribution law. A correlation analysis regarding the strength and nature of the relationship between relevant indices and the dynamics of GDP per capita in these countries is performed to identify the duration of time lags, after which this relationship is the most statistically significant. In the second stage, there are three types of regression models for estimating panel data to identify the impact on the economic growth dynamics of innovations financed by different economic sectors: 1) with fixed effects (based on the least-squares method); 2) with random effects (based on the general least squares method (GLS); 3) dynamic model for estimation of Arellano-Bond panel data, which considers time lags (based on the general method of moments (GMM)). In the third stage, using Wald's tests, Breusch-Pagan and Hausman, the adequate model specification is chosen. When choosing a dynamic model of Arellano-Bond, the Sargan test is performed to validate the parameters. The control variables in all three types of models consider net inflows and outflows of foreign investment, inflation (GDP deflator) and labour force participation rate (% of total population ages 15-64). The second and third stages of the study obtained the results as follows. It is empirically confirmed that a 1% increase in the share of government sector-funded R&D expenditures leads to a decrease in annual GDP growth per capita by an average of 0.15% (excluding time), business sector – to the increase by 0.13% with a time lag of 2 years, thanks to foreign sources – to the increase by 0.1% (without time lag); higher education sector – to the decrease by 0.78% (without time lag). It is substantiated that the state should reduce the share of direct investment in innovation. At the same time, it should focus on effective legislation, motivating the business sector and foreign investors to increase investment in research and development to stimulate economic growth in Azerbaijan and Ukraine and the development of international reproductive relations. Keywords business sector, correlation analysis, dynamic model, economic growth, financial regulations, financing structure, foreign sources, GERD, government sector, influence formalization, innovation, regression model, R&D.


2020 ◽  
Author(s):  
Habibolah Arasteh rad ◽  
Arshia Badi

AbstractBackgroundIn this paper, the SEIR dynamic model will be used to model the epidemic of coronvirus (2019-nCoV)disease. The SEIR model has been used to model infectious diseases in Malaysia.Then, the spread and control of the disease is simulated applying a PID controller. The results of this study show that the implementation of strict restrictions such as quarantine, social distancing and closure of gathering centers is effective in controlling the disease. Using the results and analyzing them, it was found that early and strict implementation of strict restrictions such as quarantine, social distance and closure of centers with a high percentage of community is very important to control this disease and prevent irreparable economic losses and depreciation of medical staff.ObjectiveModeling the prevalence and control of corona-virus (2019-nCoV)and the impact of government actions using control engineering methods.MethodIn this study, the SEIR dynamic model was used and the common data on the prevalence of the virus in Wuhan, China and Malaysia were used. As an example, the use of control target schemes is simulated in this paper.ResultsThe findings of this study use control methods and forecasting in control engineering to provide a clear picture of macro-decisions for different governments in the field of infectious diseases.ConclusionManagement and control schemes such as travel restrictions, quarantine, social distance and closure of offices, higher education institutions must be implemented immediately to prevent major economic and social losses. The implementation of these restrictions should not be delayed during the outbreak of corona-virus(2019-nCoV) infectious diseases.


2020 ◽  
Vol 3 (1) ◽  
pp. 018-022
Author(s):  
Liu Junjie ◽  
Wang Ke ◽  
Deng Zhiyong ◽  
Cao Jinming ◽  
Zhao Bin

2008 ◽  
Vol 45 ◽  
pp. 147-160 ◽  
Author(s):  
Jörg Schaber ◽  
Edda Klipp

Volume is a highly regulated property of cells, because it critically affects intracellular concentration. In the present chapter, we focus on the short-term volume regulation in yeast as a consequence of a shift in extracellular osmotic conditions. We review a basic thermodynamic framework to model volume and solute flows. In addition, we try to select a model for turgor, which is an important hydrodynamic property, especially in walled cells. Finally, we demonstrate the validity of the presented approach by fitting the dynamic model to a time course of volume change upon osmotic shock in yeast.


1982 ◽  
Vol 15 (2) ◽  
pp. 421-438 ◽  
Author(s):  
John G. Corcoran ◽  
Stanton G. Axline

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