Question 1: In figure 1, why data set 1 is higher than data set 2, where data set 1 is for android and data set 2 is for window mobile.

Answer: The authors mention that most of users for window mobile phone do not actually use it as a mobile. They use it as a PC. Otherwise, users for Android phone use it as a mobile phone. That’s why the usage for voice when using Android phone is much higher window mobile. The authors think people who buy window mobile phone have motivation for other applications rather than voice.

Question 2: The equation the presenter show in his presentation calculates for just one application at one time. How to solve the problem when using many applications at the same time?

Answer: In the paper, the authors use another complex equation to make summation for many applications.

Question 3: Is it fair to compare energy usage between Android platform and Window Mobile platform since different platforms have different mechanisms to manage the energy?

Answer: The point in this paper is not to compare between Android platform and Window Mobile platform. It did not say which is better and which is worse. It gave solution for prediction. They use android because it’s open source and only it could support the battery level sensing. Moreover, half of the authors are from Microsoft so it’s easy for them to deploy the window mobile and do experiments.