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Estimating the instantaneous reproduction number(R_(t))by using particle filter

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Infectious Disease modelling 2023年第4期8卷 1002-1014页

作者： Yong Sul Won Woo-Sik Son Sunhwa Choi Jong-Hoon Kim National Institute for Mathematical Sciences DaejeonSouth Korea International Vaccine Institute SeoulSouth Korea

Background:Monitoring the transmission of coronavirus disease 2019(COVID-19)requires accurate estimation of the effective reproduction number(Rt).However,existing methods for calculating Rt may yield biased estimates if important real-world factors,such as delays in confirmation,pre-symptomatic transmissions,or imperfect data observation,are not ***:To include real-world factors,we expanded the susceptible-exposed-infectiousrecovered(SEIR)model by incorporating pre-symptomatic(P)and asymptomatic(A)states,creating the SEPIAR *** utilizing both stochastic and deterministic versions of the model,and incorporating predetermined time series of Rt,we generated simulated datasets that simulate real-world challenges in estimating *** then compared the performance of our proposed particle filtering method for estimating Rt with the existing EpiEstim approach based on renewal ***:The particle filtering method accurately estimated Rt even in the presence of data with delays,pre-symptomatic transmission,and imperfect *** evaluating via the root mean square error(RMSE)metric,the performance of the particle filtering method was better in general and was comparable to the EpiEstim approach if perfectly deconvolved infection time series were provided,and substantially better when Rt exhibited short-term fluctuations and the data was right ***:The SEPIAR model,in conjunction with the particle filtering method,offers a reliable tool for predicting the transmission trend of COVID-19 and assessing the impact of intervention *** approach enables enhanced monitoring of COVID-19 transmission and can inform public health policies aimed at controlling the spread of the disease.

关键词： Particle filter Sequential Monte Carlo Effective reproduction number COVID-19 transmission model Compartment model

Assessing the mechanism of citywide test-trace-isolate Zero-COVID policy and exit strategy of COVID-19 pandemic

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Infectious Diseases of Poverty 2022年第5期11卷 97-98页

作者： Pei Yuan Yi Tan Liu Yang Elena Arufo Nicholas H.Ogden Guojing Yang Haixia Lu Zhigui Lin Weichuan Lin Wenjun Ma Meng Fan Kaifa Wang Jianhe Shen Tianmu Chen Huaiping Zhu Laboratory of Mathematical Parallel Systems(LAMPS) Department of Mathematics and StatisticsYork University4700 Keele StreetTorontoON M3J1P3Canada Key Laboratory of Tropical Translational Medicine of Ministry of Education and School of Tropical Medicine and Laboratory Medicine The First Afliated Hospital of Hainan Medical UniversityHainan Medical UniversityHaikouHainanChina 不详

Background:Countries that aimed for eliminating the cases of COVID-19 with test-trace-isolate policy are found to have lower infections,deaths,and better economic performance,compared with those that opted for other mitigation ***,the continuous evolution of new strains has raised the question of whether COVID-19 eradication is still possible given the limited public health response capacity and fatigue of the *** aim to investigate the mechanism of the Zero-COVID policy on outbreak containment,and to explore the possibility of eradication of Omicron transmission using the citywide test-trace-isolate(CTTI)***:We develop a compartmental model incorporating the CTTI Zero-COVID policy to understand how it contributes to the SARS-CoV-2 *** employ our model to mimic the Delta outbreak in Fujian Province,China,from September 10 to October 9,2021,and the Omicron outbreak in Jilin Province,China for the period from March 1 to April 1,*** and sensitivity analyses were conducted using dynamical system and Latin Hypercube Sampling/Partial Rank Correlation Coefcient(PRCC).Results:Calibration results of the model estimate the Fujian Delta outbreak can end in 30(95%confdence interval CI:28–33)days,after 10(95%CI:9–11)rounds of citywide *** emerging Jilin Omicron outbreak may achieve zero COVID cases in 50(95%CI:41–57)days if supported with sufcient public health resources and population compliance,which shows the efectiveness of the CTTI Zero-COVID ***:The CTTI policy shows the capacity for the eradication of the Delta outbreaks and also the Omicron ***,the implementation of radical CTTI is challenging,which requires routine monitoring for early detection,adequate testing capacity,efcient contact tracing,and high isolation compliance,which constrain its benefts in regions with limited ***,these challenges become even more acute in the face of more contagious variant

关键词： COVID-19 transmission model Zero-COVID policy Citywide testing Test-trace-isolate Exit strategy

International chicken trade and increased risk for introducing or reintroducing highly pathogenic avian influenza A (H5N1) to uninfected countries

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Infectious Disease modelling 2017年第4期2卷 412-418页

作者： Jennifer M.Radin Richard A.Shaffer Suzanne P.Lindsay Maria Rosario GAraneta Rema Raman James H.Fowler Joint Doctoral Program in Public Health(Epidemiology) San Diego State University/University of CaliforniaSan DiegoLa JollaCA 92093USA Division of Epidemiology and Biostatistics San Diego State UniversitySan DiegoCA 92182USA Department of Family and Preventive Medicine University of CaliforniaSan DiegoLa JollaCA 92093USA Department of Political Sciences University of CaliforniaSan DiegoLa JollaCA 92093USA Division of Medical Genetics University of CaliforniaSan DiegoLa JollaCA 92093USA

Every year billions of chickens are shipped thousands of miles around the globe in order to meet the ever increasing demands for this cheap and nutritious protein ***,transporting chickens internationally can also increase the chance for introducing zoonotic viruses,such as highly pathogenic avian influenza A(H5N1)to new *** study used a retrospective analysis of poultry trading data from 2003 through 2011 to assess the risk of H5N1 poultry infection in an importing *** found that the risk of infection in an importing country increased by a factor of 1.3(95%CI:1.1e1.5)for every 10-fold increase in live chickens imported from countries experiencing at least one H5N1 poultry case during that *** results suggest that the risk in a particular country can be significantly reduced if imports from countries experiencing an outbreak are decreased during the year of infection or if biosecurity measures such as screening,vaccination,and infection control practices are *** findings show that limiting trade of live chickens or increasing infection control practices during contagious periods may be an important step in reducing the spread of H5N1 and other emerging avian influenza viruses.

关键词： Highly pathogenic avian influenza A(H5N1) Poultry trade transmission model Zoonotic disease

Minimization of Electric Power Losses on 132 kV and 220 kV Uganda Electricity transmission Lines

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Energy and Power Engineering 2023年第2期15卷 127-150页

作者： Ounyesiga Living Stephen Ndubuisi Nnamchi Kelechi John Ukagwu Abubakar Abdulkarim Zaid Oluwadurotimi Jagun Department of Electrical Telecom and Computer Engineering SEAS Kampala International University Kampala Uganda Department of Mechanical Engineering SEAS Kampala International University Kampala Uganda Department of Electrical Engineering Faculty of Engineering Ahmadu Bello University Zaria Nigeria Department of Computer Engineering Olabisi Onabanjo University Ago-Iwoye Nigeria

The classical minimization of power losses in transmission lines is dominated by artificial intelligence techniques, which do not guarantee global optimum amidst local minima. Revolutionary and evolutionary techniques are encumbered with sophisticated transformations, which weaken the techniques. Power loss minimization is crucial to the efficient design and operation of power transmission lines. Minimization of losses is one way to meet steady grid supply, especially at peak demand. Thus, this paper has presented a gradient technique to obtain optimal variables and values from the power loss model, which efficiently minimizes power losses by modifying the traditional power loss model that combines Ohm and Corona losses. Optimality tests showed that the unmodified model does not support the minimization of power losses on transmission lines as the Hessian matrix portrayed the maximization of power losses. However, the modified model is consistent with the gradient method of optimization, which yielded optimum variables and values from the power loss model developed in this study. The unmodified (modified) models for Bujagali-Kawanda 220 kV and Masaka West-Mbarara North 132 kV transmission lines in Uganda showed maximum power losses of 0.406 (0.391) and 0.452 (0.446) kW/km/phase respectively. These results indicate that the modified model is superior to the unmodified model in minimizing power losses in the transmission lines and should be implemented for the efficient design and operation of power transmission lines within and outside Uganda for the same transmission voltages.

关键词： Minimization Power Losses transmission Lines Corona and Ohms Losses transmission model

Estimating the basic reproductive ratio for the Ebola outbreak in Liberia and Sierra Leone

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Infectious Diseases of Poverty 2015年第1期4卷 114-121页

作者： Adnan Khan Mahim Naveed Muhammad Dur-e-Ahmad Mudassar Imran Department of Mathematics Lahore University of Management SciencesLahorePakistan Department of Mathematics State University of New York at PlattsburghPlattsburghNYUSA Department of Mathematics Waterloo UniversityWaterlooONCanada Department of Mathematics and Natural Sciences GULF University for Science and TechnologyMubarak Al-AbdullahWest MishrefKuwait

Background:Ebola virus disease has reemerged as a major public health crisis in Africa,with isolated cases also observed globally,during the current ***:To estimate the basic reproductive ratio R0,which is a measure of the severity of the outbreak,we developed a SEIR(susceptible-exposed-infected-recovered)type deterministic model,and used data from the Centers for Disease Control and Prevention(CDC),for the Ebola outbreak in Liberia and Sierra *** different data sets are available:one with raw reported data and one with corrected data(as the CDC suspects under-reporting).Results:Using a deterministic ordinary differential equation transmission model for Ebola epidemic,the basic reproductive ratio R0 for Liberia resulted to be 1.757 and 1.9 for corrected and uncorrected case data,*** Sierra Leone,R0 resulted to be 1.492 and 1.362 for corrected and uncorrected case data,*** each of the two cases we considered,the estimate for the basic reproductive ratio was initially greater than unity leading to an epidemic ***:We obtained robust estimates for the value of R0 associated with the 2014 Ebola outbreak,and showed that there is close agreement between our estimates of *** of our model also showed that effective isolation is required,with the contact rate in isolation less than one quarter of that for the infected non-isolated population,and that the fraction of high-risk individuals must be brought to less than 10%of the overall susceptible population,in order to bring the value of R0 to less than 1,and hence control the outbreak.

关键词： Epidemiology Ebola virus disease transmission model Basic reproductive ratio