preprocess.dataset = function()
{   
    csv.file = "spambase.data"
    
    dataset = read.csv(file.path(orig.dir, csv.file),
                       header = FALSE)
    
    colnames(dataset) = c("word_freq_make", "word_freq_address", "word_freq_all",
                          "word_freq_3d", "word_freq_our", "word_freq_over", 
                          "word_freq_remove", "word_freq_internet", 
                          "word_freq_order", "word_freq_mail", "word_freq_receive",
                          "word_freq_will", "word_freq_people", "word_freq_report",
                          "word_freq_addresses", "word_freq_free", 
                          "word_freq_business", "word_freq_email", "word_freq_you",
                          "word_freq_credit", "word_freq_your", "word_freq_font",
                          "word_freq_000", "word_freq_money", "word_freq_hp",
                          "word_freq_hpl", "word_freq_george", "word_freq_650",
                          "word_freq_lab", "word_freq_labs", "word_freq_telnet",
                          "word_freq_857", "word_freq_data", "word_freq_415", 
                          "word_freq_85", "word_freq_technology", "word_freq_1999",
                          "word_freq_parts", "word_freq_pm", "word_freq_direct",
                          "word_freq_cs", "word_freq_meeting", "word_freq_original",
                          "word_freq_project", "word_freq_re", "word_freq_edu",
                          "word_freq_table", "word_freq_conference", "char_freq_;",
                          "char_freq_(", "char_freq_[", "char_freq_!", "char_freq_$",
                          "char_freq_#", "capital_run_length_average", 
                          "capital_run_length_longest", "capital_run_length_total",
                          "class")
    
    dataset = dataset %>% 
        mutate(class = factor(class))

    return(dataset)
}