Three Belgian researchers (U. of Liege) look at one unified approach to on-line dynamic security assessment and control to enable a power system to withstand unexpected contingencies without experiencing voltage or transient instabilities. The problem has greatly increased since deregulation, when utilities are being operated much closer to their limits in order to generate private profit. Their approach is called Single Machine Equivalent, SIME to its friends, and is a hybrid direct-temporal method that processes information about the system behavior in order to get one-shot stability assessment in the same way as direct methods. Preventative SIME relies on time-domain programs to get information about simulated stability scenarios of anticipated contingencies, and emergency SIME uses real-time measurements that take into account the actual occurrence of a contingency. Annotation copyrighted by Book News, Inc., Portland, OR