Despite its importance, the mechanics of bedrock erosion are not well understood because channel form, river hydraulics, sediment transport, and erosion mechanics coevolve over relatively long time scales that prevent direct observations, and because erosive events occur intermittently and are difficult and dangerous to measure.
The problem of tracking multiple intermittently speaking speakers is difficult as some distinct problems must be addressed.
The resource of DTSN is limited and intermittently connected to make DTSN difficult.
During her actual study sessions, Brianna either studied alone, reviewing her notes, scanning various digital resources, and doing practice problems, or with a group of friends in the library where she typically had on her headphones while surrounded by classmates who intermittently helped one another out on difficult problems.
However, the beating phenomena, in which certain frequency components of the noise vanish intermittently, may make the adaptive frequency estimation difficult.
It is a difficult and long day with Sophie waking intermittently and screaming before falling asleep again.
While Hardy is undeniably commanding as Reggie, in the more difficult role of Ronnie, he is only intermittently effective.
Furthermore, animals with latent infection that have developed an immune response may intermittently or no longer shed the organism and are therefore difficult to detect.
As the night goes on, this is becoming a bit more difficult to sustain, as fuel trucks will appear more intermittently.
The rain fell intermittently, as did the ball from nervous and greasy fingers, so it was difficult to see the quality through the drizzle of simple errors at Twickenham, unforced in the main.
