scholarly journals Multi-chain Fudan-CCDC model for COVID-19 – a revisit to Singapore’s case

2020 ◽  
Author(s):  
Hanshuang Pan ◽  
Nian Shao ◽  
Yue Yan ◽  
Xinyue Luo ◽  
Shufen Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Penalty Function ◽  
Prevention And Control ◽  
World Wide ◽  
Data Fitting ◽  
Chain Model ◽  
Single Chain ◽  
Simulation Results ◽  
Different Characteristics ◽  
And Control

AbstractBackgroundCOVID-19 has been impacting on the whole world critically and constantly since late December 2019. Rapidly increasing infections has raised intense world-wide attention. How to model the evolution of COVID-19 effectively and efficiently is of great significance for prevention and control.MethodsWe propose the multi-chain Fudan-CCDC model based on the original single-chain model in [8] to describe the evolution of COVID-19 in Singapore. Multi-chains can be considered as the superposition of several single chains with different characteristics. We identify parameters of models by minimizing the penalty function.ResultsThe numerical simulation results exhibit the multichain model performs well on data fitting. Though unsteady the increments are, they could still fall within the range of ±25% fluctuation from simulation results. It is predicted by multi-chain models that Singapore are experiencing a nonnegligible risk of explosive outbreak, thus stronger measures are urgently needed to contain the epidemic.ConclusionThe multi-chain Fudan-CCDC model provides an effective way to early detect the appearance of imported infectors and super spreaders and forecast a second outbreak. It can also explain the data in those countries where the single-chain model shows deviation from the data.

scholarly journals Multi-chain Fudan-CCDC model for COVID-19 in Iran

2020 ◽  
Author(s):  
Hanshuang Pan ◽  
Nian Shao ◽  
Yue Yan ◽  
Xinyue Luo ◽  
Ali Ahmadi ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Prevention And Control ◽  
Data Fitting ◽  
Chain Model ◽  
Single Chain ◽  
Epidemic Curve ◽  
The World ◽  
Simulation Results ◽  
Fitting In ◽  
And Control

AbstractBackgroundCOVID-19 has been deeply affecting people’s lives all over the world. It is significant for prevention and control to model the evolution effectively and efficiently.MethodsWe first propose the multi-chain Fudan-CCDC model which is based on the original Fudan-CCDC model to describe the revival of COVID-19 in some countries. Multi-chains are considered as the superposition of distinctive single chains. Parameter identification is carried out by minimizing the penalty function.ResultsFrom results of numerical simulations, the multi-chain model performs well on data fitting and reasonably interprets the revival phenomena. The band of ±25% fluctuation of simulation results could contain most seemly unsteady increments.ConclusionThe multi-chain model has better performance on data fitting in revival situations compared with the single-chain model. It is predicted by the three-chain model with data by Apr 21 that the epidemic curve of Iran would level off on round May 10, and the final cumulative confirmed cases would be around 88820. The upper bound of the 95% confidence interval would be around 96000.

Numerical Simulation of Blasting-Induced Damage in Grouting Curtain of Sandstone Aquifer for Vertical Shaft

2015 ◽  
Vol 723 ◽  
pp. 271-278
Author(s):  
Yu Liang Zhou ◽  
Dong Feng Yuan ◽  
Jun Zheng ◽  
Hua Wang
Keyword(s):  
Numerical Simulation ◽  
Prevention And Control ◽  
Damage Zone ◽  
Surrounding Rock ◽  
Damage Effect ◽  
Vertical Shaft ◽  
Control Methods ◽  
Sandstone Aquifer ◽  
And Control ◽  
Dynamic Damage

To provide a theoretical basis for water prevention and control methods and reasonable supporting techniques for vertical shaft, and to ensure the shaft construction to pass the sandstone aquifer safely and rapidly, numerical simulation using dynamic damage constitutive model, which was a user-defined constitutive modules in FLAC3D, a lagrangian analysis code in three dimensions, has been applied to investigate the dynamic damage effect in the surrounding rock of the grouting curtain near the driving working face for vertical shaft excavated by blasting. The results indicate that the distribution of the damage zone in the surrounding rock of the shaft, which decreases the effective thickness of the grouting curtain, was like a ellip-se, and that the depth of the damage zone in the surrounding rock of the shaft grouting curtain is fewer than that of the driving face floor. It can be concluded that the centre part of the driving face floor, especially the cutting hole zones, and the shaft wall in the greater horizontal stress side are the " key parts " for shaft water prevention and control methods.

Numerical Simulation of Slope Excavation in Highway Renovation and Expansion Project

2014 ◽  
Vol 580-583 ◽  
pp. 827-830
Author(s):  
Gen Chuan Luo ◽  
Zhong Ming He ◽  
Xin Luo ◽  
Qing Guo Hu
Keyword(s):  
Numerical Simulation ◽  
Stability Analysis ◽  
Stress And Strain ◽  
Regular Pattern ◽  
Expansion Process ◽  
Excavation Process ◽  
Slope Excavation ◽  
Object Use ◽  
Simulation Results ◽  
And Control

Slope stability analysis requires detect and control the stress and strain timely. Familiar with the slope‘s stress and strain changes in excavation process has important guiding significance for the actual construction. In this paper, choose a slope in Guangxi freeway renovation and expansion process as the research object. Use FLAC3D to analysis the stress and displacement simulation results of this slope excavation step by step. Summarize the excavation regular pattern.

scholarly journals Resources for Infection Prevention and Control on the World Wide Web

2009 ◽  
Vol 48 (11) ◽  
pp. 1585-1595 ◽  
Author(s):  
Laura E. Johnson ◽  
Katherine Reyes ◽  
Marcus J. Zervos
Keyword(s):  
World Wide Web ◽  
Prevention And Control ◽  
Infection Prevention ◽  
World Wide ◽  
Infection Prevention And Control ◽  
The World ◽  
And Control

scholarly journals Numerical Simulation and Experimental Study on Shaped Charge Warhead of Guided Ammunition

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Guangsong Ma ◽  
Guanglin He
Keyword(s):  
Numerical Simulation ◽  
Cone Angle ◽  
Shaped Charge ◽  
Liner Material ◽  
Penetration Ability ◽  
Simulation And Experiment ◽  
Control Section ◽  
Simulation Results ◽  
And Control ◽  
Shaped Charge Jet

To study the jet penetration capability of shaped charge warhead of guided ammunition, a variable cone angle-shaped charge liner was designed. LS-DYNA software is used to simulate the penetration capability of shaped charge warhead with three different metal materials (copper, steel, and aluminum). Numerical simulation results show that the velocity of the shaped charge jet formed by the three kinds of materials is v aluminum > v copper > v steel , and the residual velocity after penetration is V steel > V aluminum > V copper , the time when the jet starts to break is tcopper > tsteel > taluminum, and the penetration completion time is Tcopper < Taluminum < Tsteel; therefore, according to the numerical simulation results, copper was selected as the liner material, and the principle prototype is made for the experiment. The results of numerical simulation and experiment show that the shaped charge warhead with copper shaped charge liner has good penetration ability and after-effect damage ability to steel target after penetrating the guidance section, steering gear section, and control section.

scholarly journals COVID-19 in Singapore: Another story of success

2020 ◽  
pp. 2050001 ◽  
Author(s):  
Yue Yan ◽  
Hanshuang Pan ◽  
Nian Shao ◽  
Yan Xuan ◽  
Shufen Wang ◽  
...  
Keyword(s):  
East Asia ◽  
Prevention And Control ◽  
Source Term ◽  
Data Fitting ◽  
Isolation Rate ◽  
The Future ◽  
And Control

In this paper, we develop the Fudan-CCDC model by adding a source term to describe the imported infectors. The model is applied to analyze the situation of COVID-19 in East Asia, and then in Singapore. By data fitting, our model reveals that Singapore has a much higher isolation rate and earlier quarantine measures compared to other countries. We conclude that Singapore has been doing extraordinarily well on epidemic prevention and control. Finally we discuss the specific measures in Singapore’s success, and suggest other countries to learn from the Singapore’s style, so as to be well prepared in the future.

scholarly journals Optimal Operation of Building Microgrids with Rooftop Greenhouse Under Component Outages in Islanded Mode

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1930
Author(s):  
Se-Hyeok Choi ◽  
Akhtar Hussain ◽  
Hak-Man Kim
Keyword(s):  
Numerical Simulation ◽  
Optimal Operation ◽  
Weight Matrix ◽  
Normal Operation ◽  
Control Parameters ◽  
Available Energy ◽  
Local Resources ◽  
Islanded Mode ◽  
Simulation Results ◽  
And Control

An optimal operation scheme for a building microgrid with a rooftop greenhouse in islanded mode is proposed in this paper. In islanded mode, the fulfillment of entire demand is challenging due to the absence of connection with the utility grid and the scarcity of local resources. The situation becomes more challenging when one or more pieces of equipment fail during the islanded mode. Therefore, in addition to islanded mode operation, component outage and recovery are also considered in this paper. In order to use the available energy efficiently, prioritization of building loads and control parameters of the greenhouse are proposed. A priority weight matrix is adopted to decide the supply of energy to fulfill the requirements of control parameters in the case of insufficient energy. In addition to the normal operation bounds, new bounds are defined to operate the control parameters if the resources are not sufficient. Additional penalties are imposed if the new bounds are chosen, due to violation of the normal operation range. The microgrid system is rescheduled if any component outage or recovery is detected from the outage point to the end of the scheduling horizon. The performance of the proposed method is evaluated by carrying out several simulations including component outage, component recovery, and simultaneous outage of two or more types of equipment. Numerical simulation results have demonstrated the effectiveness of the proposed operation scheme for optimal operation of building microgrids with a rooftop greenhouse in islanded mode.

GMS Numerical Simulation of Crude Oil Pollution Caused by Some Oil Pipeline Leak

2012 ◽  
Vol 488-489 ◽  
pp. 1076-1081
Author(s):  
Jian Hua Ye ◽  
Yu Feng Ren ◽  
Shu Kun Luo
Keyword(s):  
Numerical Simulation ◽  
Environmental Monitoring ◽  
Crude Oil ◽  
Groundwater Pollution ◽  
Prevention And Control ◽  
Groundwater Modeling ◽  
Oil Pollution ◽  
Oil Pipeline ◽  
Crude Oil Pollution ◽  
And Control

We have used Groundwater Modeling System (GMS) to numerical simulate the groundwater pollution migration caused by crude oil leak in the research regions. The result of the numerical simulation shows those 40 years after the crude oil leak, the contaminative area of pollutant reaches 46595 m3, and then the pollutant doesn’t arrive the pumping well. The density of the pollutants is less than 0.01mg/L. Therefore, we suggest that pipeline projects should make a specific effective plan for groundwater environmental monitoring for the sake of providing reference to institute relative countermeasure for prevention and control groundwater pollution.

Method of the Safety Early Warning on Hazard Installations

2010 ◽  
Vol 34-35 ◽  
pp. 806-810
Author(s):  
Jing Zhang
Keyword(s):  
Quantitative Analysis ◽  
Early Warning ◽  
Prevention And Control ◽  
Processing System ◽  
Actual Situation ◽  
Information Processing Model ◽  
Effective Combination ◽  
Simulation Results ◽  
And Control ◽  
And Diffusion

The early warning can improve the monitoring and management of the hazard installations, realize the prevention and control in advance. Many early warning methods do not have the forecast and simulation of the hazard consequences and early warning information is not comprehensive. The hazard installations warning process and hazard assessment technology are analyzed and studied, and qualitative analysis and quantitative analysis are carried out. With the effective combination of hazard consequences and early warning technology, the processing system of hazard installation early warning process information is presented, the hazard installation early warning information processing model is designed, the hazard installation early warning is improved, and the accuracy and efficiency of early warning is improved. With examples, the hazard consequences of leak and diffusion are simulated. Experiments prove that the early warning simulation structure and early warning method are effective, and that the simulation results are close to the actual situation with better application value.

scholarly journals Preliminary Basic Research on the Optimization of Oil Spill Prevention and Control Design Based on Numerical Simulation Technology for Zhoushan Ma’ao Port Area

2021 ◽  
Author(s):  
Junyan Dong ◽  
Zhibo Tang ◽  
Hanbao Chen
Keyword(s):  
Numerical Simulation ◽  
Oil Spill ◽  
Prevention And Control ◽  
Control Design ◽  
Basic Research ◽  
Port Area ◽  
And Control ◽  
The Relationship ◽  
Control Designs ◽  
Related Process

This paper gives a general overview of relevant studies about oil spill emergency control designs, analyzes and discusses the structure, function and main contents of these designs. Besides, the paper proposes an integrated and practical design of emergency response steps, with related process. Taking the port area of Ma’ao as a case, this paper comprehensively studies the relationship between the time of rescue vessels arriving at the oil spill location and the range of the port that can be covered by these vessels as well as the protection facilities required for the relevant shoreline.

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