Those unconventional threats might include cyber-ops, lone-wolf terrorists, energy and infrastructure threats, and information warfare — challenges ill suited to a response from NATO's prized "mobile and deployable" forces, and for which proportional responses are difficult to devise.
For example, models of multiple organ failure are difficult to devise.
There are still complaints that it is difficult to devise a survey that is appropriate for every institution.
A direct effort to outlaw the Rangers' approach would require separate rules for forwards and defencemen, which would be difficult to devise and virtually impossible to enforce.
Good, careful, and controlled field experiments are a relative rarity in political science; it's difficult to devise and execute rigorous studies outside of the laboratory.
Unfortunately, if you are not already holding such stocks, it is difficult to devise a trading strategy to profit from the seasonal pattern.
In fact, the recommendations on calcium are now so high that it is difficult to devise practical diets that meet them.
The truth is that it is difficult to devise a credible plan not merely to boost the lowest wages (a thorny enough problem) but to win a rise for the bulk of the workforce.
Yet it's been difficult to devise regulations governing this noise, because scientists have not fully understood how sounds reach the baleen whales' ear bones.
However, it will be difficult to devise a data compression technique based on CS for such cases without a thorough understanding of its performance, reconstruction accuracy, practical implementation and generality.
When comparing the performance of different compression methods, it is difficult to devise a comparison strategy between different compression methods that allows easy predictions since lossy compression performance and accuracy are in general highly data dependent.
