smallpox epidemics using a computational model利用一个计算机模型预防天花课件

Preventing Smallpox Epidemics Using a Computational Model By Chintan Hossain and Hiren Patel Facts About Smallpox nSymptoms occur in stages nHighly contagious (causes epidemics) nFatal in 30% cases nThere is a vaccine - Death may occur GOAL (Objective) nPrevent smallpox epidemics via. vaccination. nVaccinate as few as possible because: 1. Minimize reactions 2. Reduce cost HYPOTHESISHYPOTHESIS: Vaccinating certain percentage : Vaccinating certain percentage of the population may be sufficient to of the population may be sufficient to prevent a smallpox epidemic.prevent a smallpox epidemic. Stages of Smallpox nNormal (Susceptible) nImmune (or vaccinated) nIncubation nFirst Stage nEarly Symptoms nLate Symptoms nDeath Vaccination Contraction 14 days3 days9 days Recovery 9 days 0.1% chance / day 0.5% chance / day 3.0% chance / day Normal (Susceptible) Incubation Death First Stage Late Symptoms Early Symptoms Immune Vaccinated Our Model: Social Networks nCliques Represent: Families Workplaces School Our Society Generator Algorithm nUse random numbers to pick a family size. nGenerate a clique of that size. nRepeat to create more families. nUse a similar technique to generate schools and workplaces. uSchools and workplaces connect existing vertices, not new vertices. Our Model Comes Alive! n MARKOV GRAPH + SOCIETY NETWORK SIMULATION nAdvance time 1 day uSpread Disease uAdvance Stages uDeath Normal (Susceptible) Infected Stage Vaccinated / Immune Death FIRST Spread EARLYLATE Incubation DEAD Procedure nRun the society generator nVaccinate k% of people with most friends (vertices with the greatest degree) uControl: k = 0% uVariable: Vary percent, k, vaccinated nRandomly, infect one person. nRun simulation, and observe results (percent infect and length of epidemic) OUR PROGRAM Results n n Epidemics Epidemics intensify, intensify, reach a reach a peak, and peak, and then vanishthen vanish n n Vaccination Vaccination reduces reduces intensity intensity and speed.and speed. Results (cont) nVaccinating more people decreases the % infected nThe % infected becomes small if over 50% are vaccinated. Conclusion nVaccinating 50% of the population effectively prevents epidemics. nVaccinating less than 50% may not prevent an epidemic, but it reduces the severity and speed of the epidemic. n n This model can be use