public RuleBase() {
        // create our two dimensional array that will store our pre-defined fuzzy rules
        // start by creating rules for the temperature sensor
        this.tempRules = new LinkedHashMap<>();
        this.ultrasonicRules = new LinkedHashMap<>();

        // look up table for temperature sensor
        // parameters: key, value
        this.tempRules.put(very_cold, "Very cold"); // 
        this.tempRules.put(moderately_cold, "Cold");
        this.tempRules.put(moderately_warm, "Warm");
        this.tempRules.put(moderately_hot, "Hot");
        this.tempRules.put(very_hot, "Very hot");
        
        this.ultrasonicRules.put(away, "Away");
        this.ultrasonicRules.put(present, "Present");
        this.ultrasonicRules.put(away_2, "Away");
    }