scholarly journals Analysis of the real number of infected people by COVID-19: A system dynamics approach

PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0245728
Author(s):  
Bo Hu ◽  
Matthias Dehmer ◽  
Frank Emmert-Streib ◽  
Bo Zhang
Keyword(s):  
System Dynamics ◽  
Accurate Estimate ◽  
Management Tools ◽  
Monte Carlo Optimization ◽  
Infected People ◽  
Numerical Development ◽  
Daily Data ◽  
Spread Dynamics ◽  
Novel Virus ◽  
Considerable Period

At the beginning of 2020, the COVID-19 pandemic was able to spread quickly in Wuhan and in the province of Hubei due to a lack of experience with this novel virus. Additionally, authories had no proven experience with applying insufficient medical, communication and crisis management tools. For a considerable period of time, the actual number of people infected was unknown. There were great uncertainties regarding the dynamics and spread of the Covid-19 virus infection. In this paper, we develop a system dynamics model for the three connected regions (Wuhan, Hubei excl. Wuhan, China excl. Hubei) to understand the infection and spread dynamics of the virus and provide a more accurate estimate of the number of infected people in Wuhan and discuss the necessity and effectivity of protective measures against this epidemic, such as the quarantines imposed throughout China. We use the statistics of confirmed cases of China excl. Hubei. Also the daily data on travel activity within China was utilized, in order to determine the actual numerical development of the infected people in Wuhan City and Hubei Province. We used a multivariate Monte Carlo optimization to parameterize the model to match the official statistics. In particular, we used the model to calculate the infections, which had already broken out, but were not diagnosed for various reasons.

scholarly journals Introducing a strategic perspective in lean thinking applications through system dynamics modelling: the dynamic Value Stream Map

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Guido Noto ◽  
Federico Cosenz
Keyword(s):  
System Dynamics ◽  
Management Practices ◽  
System Structure ◽  
Illustrative Case ◽  
Management Tools ◽  
Lean Thinking ◽  
Content Type ◽  
Value Stream ◽  
Strategic Perspective ◽  
Value Stream Map

PurposeLean Thinking is an operation management discipline which aims to identify, map and analyse the activities forming a process to detect “value waste” and outline the most effective flow of activities to execute in sequence. Process mapping is often developed in lean projects through the use of the Value Stream Map (VSM). Like many other management tools, the VSM adopts a static and non-systemic perspective in the representation of an organizational process. This may result in the implementation of Lean projects inconsistent with the overall organizational long-term strategy, thus leading to dysfunctional performance. In order to overcome this limit, the paper suggests combining VSM with System Dynamics (SD) modelling.Design/methodology/approachThe paper is based on a review of the literature on VSM. This review is matched with an analysis of SD modelling principles aimed at explaining the practical and theoretical contribution of this approach to operation and strategic management practices. An illustrative case study is then provided to explore the practical implications of the proposed approach.FindingsOur results show that SD modelling provides robust methodological support to VSM and Lean Thinking due to its inner characteristics, namely: simulation, systemic view, explicit link between system structure and behaviour and effective visual representation.Originality/valueThis research proposes a novel approach to design VSMs aimed at fostering a strategic perspective in Lean Thinking applications. Such an approach connects two fields of research and practice – i.e. VSM and SD modelling – which have traditionally been kept separated or, at least, partially combined for specific organizational sub-systems, thereby neglecting a broader strategic view of the entire process system.

scholarly journals Visualized System Dynamics models as Information and Planning Tools

10.28945/2693 ◽  
2003 ◽  
Author(s):  
Hanne-Lovise Skartveit ◽  
Katherine J. Goodnow ◽  
Magnhild Viste
Keyword(s):  
System Dynamics ◽  
Dynamic Models ◽  
System Dynamic ◽  
Time System ◽  
Management Tools ◽  
Client Group ◽  
Stocks And Flows ◽  
Graphic Complexity ◽  
New Research ◽  
Dynamics Models

In this paper, we describe the use of visualization of system dynamics models as client information and management tools. System dynamics is a methodology for analyzing and understanding how complex systems change over time. System dynamic models have been developed for a broad range of information to client applications - from resource management problems to the mapping of stocks and flows on factory floors. The problem faced by many users of system dynamic models is their graphic complexity for users not trained in the field. This paper addresses new research into visualization of system dynamics models to make client information more efficient and accessible. This research involves the use of narrative, video and sound embedded in statistical material. This paper also considers one particular client group - that of politicians, planners and civil society in developing countries.

scholarly journals The Infection Rate of COVID-19 in Wuhan, China: Combined Analysis of Population Samples (Preprint)

2020 ◽  
Author(s):  
Hui-Qi Qu ◽  
Zhangkai Jason Cheng ◽  
Zhifeng Duan ◽  
Lifeng Tian ◽  
Hakon Hakonarson
Keyword(s):  
Mortality Rate ◽  
Infection Rate ◽  
Case Fatality ◽  
Mortality Rates ◽  
Accurate Estimate ◽  
Combined Analysis ◽  
Infected People ◽  
Health Measures ◽  
Asymptomatic Infections ◽  
Combined Infection

BACKGROUND The coronavirus disease (COVID-19) pandemic began in Wuhan, China, in December 2019. Wuhan had a much higher mortality rate than the rest of China. However, a large number of asymptomatic infections in Wuhan may have never been diagnosed, contributing to an overestimated mortality rate. OBJECTIVE This study aims to obtain an accurate estimate of infections in Wuhan using internet data. METHODS In this study, we performed a combined analysis of the infection rate among evacuated foreign citizens to estimate the infection rate in Wuhan in late January and early February. RESULTS Based on our analysis, the combined infection rate of the foreign evacuees was 0.013 (95% CI 0.008-0.022). Therefore, we estimate the number of infected people in Wuhan to be 143,000 (range 88,000-242,000), which is significantly higher than previous estimates. Our study indicates that a large number of infections in Wuhan were not diagnosed, which has resulted in an overestimated case fatality rate. CONCLUSIONS Increased awareness of the original infection rate of Wuhan is critical for proper public health measures at all levels, as well as to eliminate panic caused by overestimated mortality rates that may bias health policy actions by the authorities.

scholarly journals CBRR Model for Predicting the Dynamics of the COVID-19 Epidemic in Real Time

Mathematics ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 1727
Author(s):  
Victor Zakharov ◽  
Yulia Balykina ◽  
Ovanes Petrosian ◽  
Hongwei Gao
Keyword(s):  
Case Based Reasoning ◽  
Short Term ◽  
Infected People ◽  
The United Kingdom ◽  
Spread Dynamics ◽  
The Usa ◽  
Spread Parameters ◽  
Increasing Demand ◽  
Short Term Forecasting ◽  
Case Based

Because of the lack of reliable information on the spread parameters of COVID-19, there is an increasing demand for new approaches to efficiently predict the dynamics of new virus spread under uncertainty. The study presented in this paper is based on the Case-Based Reasoning method used in statistical analysis, forecasting and decision making in the field of public health and epidemiology. A new mathematical Case-Based Rate Reasoning model (CBRR) has been built for the short-term forecasting of coronavirus spread dynamics under uncertainty. The model allows for predicting future values of the increase in the percentage of new cases for a period of 2–3 weeks. Information on the dynamics of the total number of infected people in previous periods in Italy, Spain, France, and the United Kingdom was used. Simulation results confirmed the possibility of using the proposed approach for constructing short-term forecasts of coronavirus spread dynamics. The main finding of this study is that using the proposed approach for Russia showed that the deviation of the predicted total number of confirmed cases from the actual one was within 0.3%. For the USA, the deviation was 0.23%.

Planning Methodological Framework for Humanitarian Aid System in Colombia

2019 ◽  
pp. 245-262
Author(s):  
Feizar Javier Rueda-Velasco ◽  
Karol Moreno-Valbuena ◽  
Leonardo Gonzalez-Rodriguez
Keyword(s):  
Project Management ◽  
Response Time ◽  
System Dynamics ◽  
Humanitarian Aid ◽  
Humanitarian Logistics ◽  
Management Approach ◽  
Methodological Framework ◽  
Management Tools ◽  
Operational Strategies ◽  
System Response Time

This chapter proposes a planning methodological framework for humanitarian aid. The proposal combines project management tools and system dynamics to evaluate the effect of different operational strategies on the total system response time. System dynamics allows identifying humanitarian aid sub-systems and the feedback loops between them. The project management approach enables to recognize the response activities in each sub-system, to estimate the response time for each activity and the resources requirements. Also, the system dynamics tools enable the response times simulation under variability conditions. The proposal is tested in a retrospective way on the 1999 “Eje Cafetero” earthquake in Colombia. Additionally, the methodology framework provides a novelty approach to represent humanitarian logistics operations as a project. Finally, the integration of project representation, strategies selection, and system dynamic simulation is not enough studied in the humanitarian logistics field.

Effect of ambient temperature on incidence of tuberculosis and effect modification by meteorological factors in Jinan, China during 2012-2015: A time-series analysis

2019 ◽  
Author(s):  
Runze Ye ◽  
Liangliang Cui ◽  
Jingwen Zhou ◽  
Meihua Wang ◽  
Chongqi Jia ◽  
...  
Keyword(s):  
Meteorological Factors ◽  
Sunshine Duration ◽  
Effect Modification ◽  
Effect Of Temperature ◽  
Delayed Effect ◽  
Cold Effect ◽  
Infected People ◽  
Distributed Lag ◽  
Daily Data ◽  
Increased Risk

Abstract Objective For assessing the nonlinearity and delayed effect of temperature on incidence of tuberculosis and effect modification by meteorology factors, daily data on meteorological factors, air pollutants and incidence were obtained in Jinan, China, from 2012 to 2015.Methods A distributed lag non-linear model (DLNM) combined with quasi-Poisson regression model was employed to assess the associations. We further built a series of weather-stratified models to assess the effect modification by meteorological factors.Results The correlation between tuberculosis cases and daily average temperature (Tmean) was negatively nonlinear with a delayed effect. At the current day (lag 0), the increase of Tmean decreased the risk of tuberculosis incidence; over lag 0-70 days, the decrease of low Tmean and the increase of the high Tmean both indicated the increased risk of TB. The cold temperature showed an immediate effect at the current day, with a harvesting effect in the following days. The effect modifications by relative humidity, wind speed and sunshine duration were observed. Conclusion The cold effect accelerates the onset of potentially infected people in the short term. It is necessary to consider effect modification by meteorological factors in assessing temperature effects on incidence of tuberculosis. Which might shed light on the strategy of tuberculosis prevention and control.

Simulation of management systems of forest infrastructure

2015 ◽  
Vol 5 (2) ◽  
pp. 177-187
Author(s):  
Васильев ◽  
Oleg Vasilyev ◽  
Корныльева ◽  
Yuliya Kornylyeva
Keyword(s):  
System Dynamics ◽  
Discrete Event Simulation ◽  
Input Data ◽  
Discrete Event ◽  
Agent Based Modeling ◽  
Management Systems ◽  
Center Problem ◽  
Management Tools ◽  
Agent Based ◽  
Event Simulation

The article considers the possibility of a modern and rapidly developing management tools – simulation, allows to obtain detailed statistics on various aspects of the system, depending on the input data. The basic modeling approaches: system dynamics, discrete-event simulation, and agent-based modeling. Forestry breeding and seed center problem to be solved with the help of simulation are substantiated. Examples of problems in other areas of forestry, which can be solved with the help of this tool, are given.

Evaluation of labor hiring policies in construction projects performance using system dynamics

2019 ◽  
Vol 69 (1) ◽  
pp. 22-43 ◽  
Author(s):  
Soroush Abbaspour ◽  
Shahin Dabirian
Keyword(s):  
System Dynamics ◽  
Construction Projects ◽  
Accurate Estimate ◽  
Project Performance ◽  
Earned Value ◽  
Time Intervals ◽  
Holistic View ◽  
Content Type ◽  
Considerable Impact ◽  
Hiring Policies

Purpose The purpose of this paper is to assess different labor hiring policies for construction projects using system dynamics (SD) which have a considerable impact on project performance. Time intervals and work crew composition are two such policies. Through the implementation of a variety of policies, a managerial opportunity presents itself for the effective allocation of human resources and improvement in project performance. Design/methodology/approach The study developed a dynamic model to assess different labor hiring policies using SD based on literature. To further distinguish between findings, the effects of the applied policies on performance were considered using earned value management. Based on a real case for validating the model, the paper discusses the potential benefits of the model, including: having a systematic and holistic view, considering dynamic the labor need and allocation, identifying alternative strategies for performance improvement and simulating the reality of the projects in a virtual model. Findings The achieved simulation results show how different hiring policies affect project performance. This research model can aid decision makers to assess labor hiring policies in various time intervals with different compositions and assist them in selecting the best policies for effective implementation of project. Originality/value The proposed model would be a major attempt using SD to model labor hiring policies more accurate in construction projects performance. In fact, an accurate estimate of labor needed, along with the proper planning and implementing of various labor hiring policies, presents a managerial opportunity whereby the effective allocation of workforces can be optimized leading to drastic improvement in project performance.

scholarly journals The Infection Rate of COVID-19 in Wuhan, China: Combined Analysis of Population Samples

10.2196/20914 ◽  
2020 ◽  
Vol 22 (8) ◽  
pp. e20914
Author(s):  
Hui-Qi Qu ◽  
Zhangkai Jason Cheng ◽  
Zhifeng Duan ◽  
Lifeng Tian ◽  
Hakon Hakonarson
Keyword(s):  
Mortality Rate ◽  
Infection Rate ◽  
Case Fatality ◽  
Mortality Rates ◽  
Accurate Estimate ◽  
Combined Analysis ◽  
Infected People ◽  
Health Measures ◽  
Asymptomatic Infections ◽  
Combined Infection

Background The coronavirus disease (COVID-19) pandemic began in Wuhan, China, in December 2019. Wuhan had a much higher mortality rate than the rest of China. However, a large number of asymptomatic infections in Wuhan may have never been diagnosed, contributing to an overestimated mortality rate. Objective This study aims to obtain an accurate estimate of infections in Wuhan using internet data. Methods In this study, we performed a combined analysis of the infection rate among evacuated foreign citizens to estimate the infection rate in Wuhan in late January and early February. Results Based on our analysis, the combined infection rate of the foreign evacuees was 0.013 (95% CI 0.008-0.022). Therefore, we estimate the number of infected people in Wuhan to be 143,000 (range 88,000-242,000), which is significantly higher than previous estimates. Our study indicates that a large number of infections in Wuhan were not diagnosed, which has resulted in an overestimated case fatality rate. Conclusions Increased awareness of the original infection rate of Wuhan is critical for proper public health measures at all levels, as well as to eliminate panic caused by overestimated mortality rates that may bias health policy actions by the authorities.

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