Simple MonteCarlo simulation

montecarlo.R

####### load required packages and ste seed ########

library(mc2d) #for PERT distribution
library(ggplot2) #for plotting
set.seed(1501)

DDoS <- 10 #Number of DDoS attacks per year
software_cost <- 100000 #Cost of new technology
DDoS_new <- runif(n=1000,min=3,max=6) #Num of attacks after investment 
downtime_min <- 2 
downtime_max <- 24
downtime_avg <- 6
downtime_cost <- 1000
brand_damage_min <- 50000
brand_damage_max <- 150000

####### without investment ########

no_invest <- rpois(n=1000,DDoS) * (runif(n=1000,min=brand_damage_min,
                                 max=brand_damage_max) +
                        rpert(1000,downtime_min,downtime_avg,downtime_max,
                              4)*downtime_cost) 

print(paste("Without investment Annualised Loss Expectancy at the 10th Percentile is",
            round(quantile(no_invest,.1),2),", ",round(median(no_invest,.1),2),
            " at the Median", "& ",round(quantile(no_invest,.9),2),
            " at the 90th Percentile"))

######## with investment ########

invest <- rpois(n=1000,DDoS_new) * (runif(n=1000,min=brand_damage_min,
                                 max=brand_damage_max) +
                             rpert(1000,downtime_min,downtime_avg,downtime_max,
                                   4)*downtime_cost) + software_cost

print(paste("With investment Annualised Loss Expectancy at the 10th Percentile is",
            round(quantile(invest,.1),2),", ",round(median(invest,.1),2),
            " at the Median", "& ",round(quantile(invest,.9),2),
            " at the 90th Percentile"))

####### plot the distributions of the monte carlo simulations #######

ALE <- data.frame(investment = c(rep("Investment",1000),rep("No Investment",1000)),
                  Cost=c(invest/100000,no_invest/100000))

ggplot(ALE,aes(x=Cost))+geom_density(aes(fill=factor(investment),
                                               colour=factor(investment)),
                                           alpha=0.4)+
  scale_colour_manual("",values=c("Investment"="black","No Investment"="red"))+
  scale_fill_manual("",values=c("Investment"="black","No Investment"="red"))+
  xlab("Cost (£100,000)")+
  ylab("Density")+
  ggtitle("The Effect of an £100k Investment on Annualised Loss Expectancy")