preprocessDataset = function()
{   
    csv.file = "breast-cancer-wisconsin.data"
    
    dataset = read.csv(paste0(orig.dir, "/", csv.file), header=FALSE)
    
    colnames(dataset) = c("Sample code number", "Clump Thickness", 
                          "Uniformity of Cell Size", "Uniformity of Cell Shape", 
                          "Marginal Adhesion", "Single Epithelial Cell Size", 
                          "Bare Nuclei", "Bland Chromatin", "Normal Nucleoli", 
                          "Mitoses", "Class")
    
    dataset = dataset %>% select(-`Sample code number`) %>%
              filter(`Bare Nuclei` != "?") %>%
              mutate(Class=factor(Class), 
                     `Bare Nuclei`=as.integer(`Bare Nuclei`)) %>%
              droplevels()
    
    return(dataset)
}