146 5.8 S OF T WARE E NGINEERING AND T ESTING MONITORING AND CONTROL FOR DESIGN Software project management is crucial to the success of a project. The basic task is to plan the detailed implementation of the development process to ensure that the cost and quality objectives are met. It specifies what is needed to meet the cost, quality, and schedule objectives. For this purpose we need monitoring and control. Monitoring obtains information from the development process and exerts the required control over it. Figure 5.27 shows where monitoring and control is carried out in project management: FIGURE 5.27 Phases of Project Management Monitoring and control systems are an important class of a real-time system. They check sensors and provide information about the system's environment and take actions depending on the sensor reading. Monitoring systems take action when some exceptional sensor value is detected. Control systems continuously control hardware actuators depending on the value of associated sensors. Consider the following example: A burglar alarm system is to be implemented for a building. This uses several different types of sensors. These include movement detectors in individual rooms, window sensors on ground floor windows, which detect if a window has been broken, and door sensors, which detect a door opening on corridor doors. There are 50 window sensors, 30 door sensors, and 200 movement detectors in the system. When a sensor detects the presence of an intruder, the system automatically calls the local police and, using a voice synthesizer, reports the location of the alarm. It switches on lights in the rooms around the active sensor and sets off an audible alarm. The alarm system is normally powered by the main power source but is equipped with a battery backup. Power loss is detected using a separate power circuit monitor that monitors the main voltage. It interrupts the alarm system when a voltage drop is detected.