How are fuses related to earthquake design?
In buildings constructed to withstand earthquakes, the members in the building have "fuses" which are designed to fail before the vital members are damaged.
What does a power spectral density function tell you about a signal?
The power spectral density function breaks down a signal into different frequencies over time and shows the underlying frequencies that compose a signal.
How can I send data from one activity to another in my Android program.
You would need to send the data as an intent when calling the other activity.