Description for some variables

[sajadspeed]

Hello
I wanted to know what exactly do the following variables do?

public int scanTime = 1000;
private long changeTime = 1000;
private int focusTime = 300;
private long sleepTime = 2000;

I realized focusTime sets the time for each focus of the camera, but I did not notice the rest.
If you can explain completely and accurately, thank you very much.