protected String extractType(Engine engine) {
        if (engine.type() == Engine.Type.NONE) {
            return "none";
        } else if (engine.type() == Engine.Type.MAMDANI || engine.type() == Engine.Type.LARSEN) {
            return "mamdani";
        } else if (engine.type() == Engine.Type.TAKAGI_SUGENO) {
            return "sugeno";
        } else if (engine.type() == Engine.Type.TSUKAMOTO) {
            return "tsukamoto";
        } else if (engine.type() == Engine.Type.INVERSE_TSUKAMOTO) {
            return "inverse tsukamoto";
        }
        return "unknown";
    }