A Framework for Situation-Aware Adaptation of Service-Based Applications

Requirements For Situation-Aware Adaptation

To describe the requirements for situation-aware adaptation, we consider a crisis management scenario, which focuses on crisis situations related to a nuclear accident. Consider for example the case of a nuclear accident that caused radiation leakage and a grid of radiation sensors that monitors radiation levels in the area around the plant. The emergency plan prescribes that the Civil Protection Service subscribes to all sensors in a certain perimeter around the plant in order to detect the movement of the radioactive cloud. An extraordinary situation could be that in a short time after the accident, the wind increases and changes direction (e.g., North-West direction) while the weather forecast indicates that the wind direction will remain the same for the rest of the day. The ideal reaction to this situation, both in terms of cost and load processing, would be for the system to be subscribed at the right time only to events coming from sensors located south-east of the plant and are in a certain distance from it, which depends on the wind’s velocity or other weather conditions like humidity. Based on the information gathered from radiation sensors, authorities expect that certain cities south-east of the plant will be affected and need to inform people in these areas to follow some precautions or evacuate the area. This is normally done by transmitting TV and Radio messages, however, in the extraordinary situation in which there is a power loss, a proper reaction would be to deploy police forces and inform people using manual means such as speakerphones.

By studying similar scenarios identified within the PLAY FP7 ICT project (www.play-project.eu), we summarize the following requirements for situation-aware adaptivity (Table 1).