recording systems and speech-to-text translation software) may make this approach less practical and viable in time-pressured, fast-paced operations. Psycho-physiological measures also serve as process indices of operator SA by providing an assessment of the relationship between human performance and a corrected change in the operator's physiology. In other words, cognitive activity is associated with changes in the operator's physiological states. For example, the operator's overall functional state (as assessed using psycho-physiological measures, such as electroencephalography data, eyeblinks, and cardiac activity) may provide an indication as to whether the operator is sleep fatigued at one end of the continuum, or mentally overloaded at the other end. Other psycho-physiological measures, such as event-related potentials, event-related desynchronization, transient heart rate, and electrodermal activity, may be useful for evaluating an operator's perception of critical environmental cues, that is, to determine if the operator has detected and perceived a task-relevant stimulus. In addition, it is also possible to use psycho-physiological measures to monitor operators' environmental expectancies, that is, their physiological responses to upcoming events, as a measure of their current level of SA. Multi-faceted approach to measurement The multivariate nature of SA significantly complicates its quantification and measurement, as it is conceivable that a metric may only tap into one aspect of the operator's SA. Further, studies have shown that different types of SA measures do not always correlate strongly with each other. Accordingly, rather than rely on a single approach or metric, valid and reliable measurement of SA should utilize a battery of distinct yet related measures that complement each other. Such a multi-faced approach to SA measurement capitalizes on the strengths of each measure while minimizing the limitations inherent in each. Limitations Situation awareness is limited by sensory input and available attention, by the individual's knowledge and experience, and by their ability to analyse the available information effectively. Attention is a limited resource, and may be reduced by distraction and task loading. Comprehension of the situation and projection of future status depend heavily on relevant knowledge, understanding, and experience in similar environments. Team SA is less limited by these factors, as there is a wider knowledge and experience base, but it is limited by the effectiveness of communication within the team. Training Following Endsley's paradigm and with cognitive resource management model with neurofeedback techniques, Spanish Pedagogist María Gabriela López García (2010) implemented and developed a new SA training pattern. The first organization to